汽车专业毕业设计外文翻译
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Automobile Brake SystemThe braking system is the most important system in cars. If the brakes fail, theresult can be disastrous. Brakes are actually energy conversion devices, whichconvert the kinetic energy (momentum) of the vehicle into thermal energy(heat).When stepping on the brakes, the driver commands a stopping force tentimes as powerful as the force that puts the car in motion. The braking systemcan exert thousands of pounds of pressure on each of the four brakes.Two complete independent braking systems are used on the car. They are theservice brake and the parking brake.The service brake acts to slow, stop, or hold the vehicle during normal driving.They are foot-operated by the driver depressing and releasing the brake pedal.The primary purpose of the parking brake is to hold the vehicle stationary whileit is unattended. The parking brake is mechanically operated by when a separateparking brake foot pedal or hand lever is set.The brake system is composed of the following basic c omponents: the “master cylinder” which is located under the hood, and is directly connected to the brake pedal, converts driver foot’s mechanical pressure into hydraulic pressure. Steel “brake lines” and flexible “brake hoses” connect the master cylinder to the cylinders” located at each wheel. Brake fluid, specially designed to work inextreme conditions, fills the system. “Shoes” and “pads” are pushed by cylinders to contact the “drums” and “rotors” thus causing drag, which (hopefully) slows the car.The typical brake system consists of disk brakes in front and either disk ordrum brakes in the rear connected by a system of tubes and hoses that link thebrake at each wheel to the master cylinder (Figure).Basically, all car brakes are friction brakes. When the driver applies the brake, the control device forces brake shoes, or pads, against the rotating brake drum or disks at wheel. Friction between the shoes or pads and the drums or disks then slows or stops the wheel so that the car is braked.In most modern brake systems (see Figure 15.1), there is a fluid-filled cylinder, called master cylinder, which contains two separate sections, there is a piston in each section and both pistons are connected to a brake pedal in the driver compartment. When the brake is pushed down, brake fluid is sent from the master cylinder to the wheels.At the wheels, the fluid pushes shoes, or pads, against revolving drums or disks. The friction between the stationary shoes, or pads, and the revolving drums or disks slows and stops them. This slows or stops the revolving wheels, which, in turn, slow or stop the car.The brake fluid reservoir is on top of the master cylinder. Most cars todayhave a transparent reservoir so that you can see the level without opening the cover. The brake fluid level will drop slightly as the brake pads wear. This is a normal condition and no cause for concern. If the level drops noticeably over ashort period of time or goes down to about two thirds full, have your brakes checked as soon as possible. Keep the reservoir covered except for the amount of time you need to fill it and never leave a cam of brake fluid uncovered. Brakefluid must maintain a very high boiling point. Exposure to air will cause the fluidto absorb moisture which will lower that boiling point.The brake fluid travels from the master cylinder to the wheels through a seriesof steel tubes and reinforced rubber hoses. Rubber hoses are only used in places that require flexibility, such as at the front wheels, which move up and down as well as steer. The rest of the system uses non-corrosive seamless steel tubing with special fittings at all attachment points. If a steel line requires a repair, thebest procedure is to replace the compete line. If this is not practical, a line can be repaired using special splice fittings that are made for brake system repair. You must never use copper tubing to repair a brake system. They are dangerous and illegal.Drum brakes, it consists of the brake drum, an expander, pull back springs, a stationary back plate, two shoes with friction linings, and anchor pins. The stationary back plate is secured to the flange of the axle housing or to thesteering knuckle. The brake drum is mounted on the wheel hub. There is a clearance between the inner surface of the drum and the shoe lining. To apply brakes, the driver pushes pedal, the expander expands the shoes and presses them to the drum. Friction between the brake drum and the friction linings brakes the wheels and the vehicle stops. To release brakes, the driver release the pedal, the pull back spring retracts the shoes thus permitting free rotation of the wheels.Disk brakes, it has a metal disk instead of a drum. A flat shoe, or disk-brake pad,is located on each side of the disk. The shoes squeeze the rotatin g disk to stopthe car. Fluid from the master cylinder forces the pistons to move in, toward the disk. This action pushes the friction pads tightly against the disk. The friction between the shoes and disk slows and stops it. This provides the braking action. Pistons are made of either plastic or metal. There are three general types of disk brakes. They are the floating-caliper type, the fixed-caliper type, and thesliding-caliper type. Floating-caliper and sliding-caliper disk brakes use a single piston. Fixed-caliper disk brakes have either two or four pistons.The brake system assemblies are actuated by mechanical, hydraulic or pneumatic devices. The mechanical leverage is used in the parking brakes fittedin all automobile. When the brake pedal is depressed, the rod pushes the pistonof brake master cylinder which presses the fluid. The fluid flows through the pipelines to the power brake unit and then to the wheel cylinder. The fluidpressure expands the cylinder pistons thus pressing the shoes to the drum or disk.If the pedal is released, the piston returns to the initialposition, the pull backsprings retract the shoes, the fluid is forced back to the master cylinder andbraking ceases.The primary purpose of the parking brake is to hold the vehicle stationary whileit is unattended. The parking brake is mechanically operated by the driver when a separate parking braking hand lever is set. The hand brake is normally usedwhen the car has already stopped. A lever is pulled and the rear brakes are approached and locked in the “on” position. The car may now be left without fear of its rolling away. When the driver wants to move the car again, he mustpress a button before the lever can be released. The hand brake must also be ableto stop the car in the event of the foot brake failing. For this reason, it is separatefrom the foot brake uses cable or rods instead of the hydraulic system.Anti-lock Brake SystemAnti-lock brake systems make braking safer and more convenient, Anti-lockbrake systems modulate brake system hydraulic pressure to prevent the brakesfrom locking and the tires from skidding on slippery pavement or during a panicstop.Anti-lock brake systems have been used on aircraft for years, and some domesticcar were offered with an early form of anti-lock braking in late 1990’s. Recently, several automakers have introduced more sophisticated anti-lock system. Investigations in Europe, where anti-lock brakin g systems have been availablefor a decade, have led one manufacture to state that the number of trafficaccidents could be reduced by seven and a half percent if all cars had anti-lock brakes. So some sources predict that all cars will offer anti-lock brakes toimprove the safety of the car.Anti-lock systems modulate brake application force several times per second tohold the tires at a controlled amount of slip; all systems accomplish this inbasically the same way. One or more speed sensors generate alternating currentsignal whose frequency increases with the wheel rotational speed. An electroniccontrol unit continuously monitors these signals and if the frequency of a signaldrops too rapidly indicating that a wheel is about to lock, the control unitinstructs a modulating device to reduce hydraulic pressure to the brake at theaffected wheel. When sensor signals indicate the wheel is again rotatingnormally, the control unit allows increased hydraulic pressure to the brake. Thisrelease-a pply cycle occurs several time per second to “pump” the brakes like driver might but at a much faster rate.In addition to their basic operation, anti-lock systems have two other things incommon. First, they do not operate until the brakes are applied with enoughforce to lock or nearly lock a wheel. At all other times, the system stands readyto function but does not interfere with normal braking. Second, if the anti-locksystem fail in any way, the brakes continue to operate without anti-lockcapability. A warning light on the instrument panel alerts the driver when aproblem exists in the anti-lock system.The current Bosch component Anti-lock Braking System (ABSⅡ), is a second generation design wildly used by European automakers such as BWM,Mercedes-Benz and Porsche. ABSⅡ system consists of : four wheel speedsensor, electronic control unit and modulator assembly.A speed sensor is fitted at each wheel sends signals about wheel rotation tocontrol unit. Each speed sensor consists of a sensor unit and a gear wheel. Thefront sensor mounts to the steering knuckle and its gear wheel is pressed onto thestub axle that rotates with the wheel. The rear sensor mounts the rear suspension member and its gear wheel is pressed onto the axle. The sensor itself is awinding with a magnetic core. The core creates a magnetic field around the winding, and as the teeth of the gear wheel move through this field, an alternating current is induced inthe winding. The control unit monitors the rate o change in this frequency to determine impending brake lockup.divided into three parts: signal processing,The control unit’s function can belogic and safety circuitry. The signal processing section is the converter that receives the alternating current signals form the speed sensors and converts them into digital form for the logic section. The logic section then analyzes thedigitized signals to calculate any brake pressure changes needed. If impending lockup is sensed, the logic section sends commands to the modulator assembly. Modulator assemblyThe hydraulic modulator assembly regulates pressure to the wheel brakes when it receives commands from the control utuit. The modulator assembly can maintain or reduce pressure over the level it receives from the master cylinder, it also can never apply the brakes by itself. The modulator assembly consists of threehigh-speed electric solenoid valves, two fluid reservoirs and a turn deliverypump equipped with inlet and outlet check valves. The modulator electrical connector and controlling relays are concealed under a plastic cover of the assembly.Each front wheel is served by electric solenoid valve modulated independentlyby the control unit. The rear brakes are served by a single solenoid valve and modulated together using the select-low principle. During anti-braking system operation, the control unit cycles the solenoid valves to either hold or release pressure the brake lines. When pressure is released from the brake lines during anti-braking operation, it is routed to a fluid reservoir. There is one reservoir for the front brake circuit. The reservoirs are low-pressure accumulators that storefluid under slight spring pressure until the return delivery pump can return the fluid through the brake lines to the master cylinder.汽车制动系统制动系统是汽车上最重要的系统。
附录:英汉对照Automotive oxygen sensor failure andinspection of the commonThe automotive industry is currently in the international application of the sensor on one of the largest markets, and the oxygen sensor reported the number of patents, ranking the first in automotive sensors. Oxygen sensor installed in the vehicle exhaust pipe, use it to detect the oxygen content in exhaust port. Oxygen sensor and thus can be obtained in accordance with the signal, put it back to the control system tofine-tune the fuel injection, so that A / F control at best, not only greatly reduces emissions and saves energy. At present, the practical application of the oxygen sensor has zirconia dioxide oxygen sensors and the two oxygen sensors. And common oxygen sensor and a single lead, double-lead and lead of three points; single pin for Zirconia oxygen sensor; double lead for the titanium dioxide oxygen sensor;three-lead type for the heating oxygen zirconia sensors, in principle, lead the way on three of the oxygen sensor is not a substitute for use. Are one of the most widely used type of zirconia oxygen sensor.First, zirconia oxygen sensor structureIn the use of three-way catalytic converters to reduce exhaust pollution on the engine, oxygen sensors are essential components. Oxygen sensor is located in the first section of the exhaust pipe, catalytic converter at the front. There is a Oxygen Sensor zirconia (a ceramic) components manufacturers, all of its outside has a layer ofthin-plated platinum. Zirconia ceramic plated body at one end with a thin layer of platinum closed. Into the protection of the latter was set, and installed in a metal body. Further protect the protection of the role of sets played and sensor can be installed on the exhaust manifold. Ceramic exhaust external exposure, and the internal atmosphere and the environment the same.This component has a very high temperature resistance, low temperature so do not allow current through. However, when high temperature, because of the air and exhaust gas oxygen concentration difference, oxygen ions can, through this component. This raises the potential difference, platinum to enlarge. In this way,air-fuel ratio lower than the theoretical air-fuel ratio (thick), the components in the oxygen sensor in (air) outside (the atmosphere) between the oxygen concentration has a greater bad. Thus, the sensors have a relatively strong one voltage (Johnson V). On the other hand, if the rare gas mixture, air and exhaust gas oxygen concentration difference between the very small, have a sensor, there is only one relatively weak voltage (near 0 volts).Because once the mixture of air-fuel ratio deviation from the theoretical air-fuel ratio, ternary catalysts for CO, HC and NOX purification capacity will be a sharp decline, it is installed at the exhaust pipe oxygen sensor for detecting oxygen concentration in the exhaust, and ECU the issue of feedback signal, and then by theECU to control fuel injection amount of injector change, which will control the mixture at the air-fuel ratio near the theoretical value.Two, automotive oxygen sensor working principleOxygen sensor installed in the exhaust manifold, it can detect the concentration of oxygen in the exhaust, air-fuel ratio calculated, and the results sent to the ECU.For example:1, exhaust gas oxygen concentration in the high –When emissions are significant when the percentage of oxygen, ECU will accordingly determine the air-fuel ratio, and that is very dilute mixture.2, exhaust gas oxygen concentration in the low –When the percentage of oxygen in the exhaust very, ECU to determine air-fuel ratio will accordingly small, that is very strong mixture. Temperature higher than300 ℃, the ceramic materials used for the iron conductor. Under these conditions, if the percentage of oxygen sensors on both sides of the different content will have a voltage change at both ends. Two types of environment (air-side and exhaust side) of the different measurements of the oxygen content of these changes tell ECU, exhaust at the oxygen content in the remainder of the generation of harmful emissions to ensure that combustion is not appropriate percentage. Ceramic materials at temperatures lower than 300 ℃are non-linear, and thus the sensor is not a useful signal transmission. ECU has a special function, that is, heating machine at pm (open-loop operation) to stop the adjustment of the mixture. Sensors equipped with heating elements to reach operating temperature quickly. When current flows through the heating elements, it reduces the iron to make ceramics become conductors of time, and which makes the sensor can be installed in the exhaust pipe of the site later.In the three-way catalytic purifier Medium, ECU using data from the oxygen sensor to regulate the air-fuel ratio, but the method of standard Carburetor EFI device somewhat different.At EFI device, EFI's ECU fuel injection through the increase or decrease from the injected fuel volume, adjusting air-fuel ratio. If the ECU from the oxygen sensor detects the mixture too thick, it will gradually reduce the amount of fuel injection, the mixture of on-thinning. Therefore the actual air-fuel ratio becomes greater than the theoretical air-fuel ratio (more dilute). When this happens, ECU through the oxygen sensor to detect the truth, it will start a gradual increase in the volume of spray. In this way, air-fuel ratio is too low, some will Luan (more dense) until the air-fuel ratio lower than the theoretical. Thus, the cycle repeated, ECU main cloud in this way, constant changes in air-fuel ratio, the actual air-fuel ratio near the theoretical air-fuel ratio.Carburetor in the use of the device, are entered by regulating air intake air-fuel ratio of air-conditioning. Mixture theory is usually air-fuel ratio to maintain a little thick. ECU within the air-fuel ratio oxygen sensor has been the information, and manipulation, according to the actual air-fuel ratio EBCU (electronically controlled intake valve) regulator into the carburetor air intake volume. If mixture is too strong, it allows more air to enter to-thinning: If mixture is too thin, it allows less air to enter,so that moreThird, the common automotive oxygen sensor faultOnce the oxygen sensor fails, the electronic fuel injection system will enable the computer should not be the oxygen concentration in the exhaust pipe of the information, and therefore should not be on the air-fuel ratio feedback control, the engine will increase fuel consumption and exhaust pollution, engine idle speed instability, lack of fire, such as fault-surge situation. Therefore, it is necessary to troubleshoot in a timely manner or replaced.1, oxygen sensor poisoningOxygen sensor poisoning and are often more difficult to control emerging as a fault, in particular, are often the use of leaded petrol cars, even the new oxygen sensor, and can only be the work of thousands of kilometers. If only minor lead poisoning, and then use a box of unleaded petrol, will be able to eliminate the surface of oxygen sensor lead to the resumption of normal work. But often because of excessive exhaust temperature, which lead intrusion in their internal and impede the spread of oxygen ions to oxygen sensor failure can only be replaced at this time.In addition, the oxygen sensor silicon poisoning happened is common. In general, gasoline and lubricants containing silicon compounds generated by combustion silica, silicon rubber seal gasket improper use of silicone emitting gas,will cause the oxygen sensor failure, and therefore want to use good quality fuel and lubricants .Right to choose the repair and installation of rubber gaskets, coated on the sensor not to require the use of factory and other than the anti-solvent, etc.2, carbon depositionNot because of engine combustion, in the carbon deposition formed on the surface of oxygen sensor, oxygen sensor or the internal into the sediment, such as oil or dust will impede or block the external air into the oxygen sensor internal to oxygen sensor signal output inaccurate, ECU should not timely correct air-fuel ratio. Soot produced, mainly for increased fuel consumption, emission levels were significantly increased. At this point, if the sediment removal will restore normal working.3, oxygen sensor ceramic fragmentsCeramic oxygen sensor hardware and crisp, with a hard object by knocking or washing with a strong air currents blowing all its fragmentation and possible failure. Therefore, be particularly careful when handling and found that the timely replacement of problem.4, heater resistance wire blownThe heating-type oxygen sensor, if the resistance heater wire ablation, it is difficult to make sensors to reach normal operating temperature and the loss of role.5, oxygen sensor breaking off the internal circuits.Four, automotive oxygen sensor method1, oxygen sensor heater resistance checkUnplug the oxygen sensor wiring harness plug, use a multimeter resistance measurement file in the oxygen sensor heater terminal access-chu-chu with Ground between access resistance and its resistance to 4-40Ω (refer to specific modelspecification). Such as not meeting the standard, should be the replacement of oxygen sensor.2, oxygen sensor voltage feedback measurementMeasurement of oxygen sensor feedback voltage should unplug the oxygen sensor wiring harness plug, the control circuit models, the feedback from the oxygen sensor voltage output terminal on a thin wire leads, and then plug harness plugs well, in the engine operation , measured from the pinout on the feedback voltage (some models can also be inner socket fault detection by a voltage of oxygen sensor feedback, such as the production of Toyota cars can be a series of fault detection from the socket terminal OX1 or OX2 directly measured oxygen sensor feedback voltage). Oxygen sensor feedback on the test voltage, it is best to use with low-range (typically 2V) and high impedance (resistance greater than 10MΩ) multimeter pointer type. Detection of specific methods are as follows: 1) hot cars engine to normal operating temperature (or after the start-up speed of 2500r/min running 2min); 2) will file a negative voltage multimeter table T then fault detection within the socket or the battery negative electrode E1 is fault detection table T then the socket jack OX1 or OX2, or receive oxygen sensor wiring harness plug on the No. | round; 3) to allow the engine to maintain speed around 2500r/min operation voltage meter at the same time check whether the pointer back and forth between 0-1V swing, with a note of voltage meter pointer 10s the number of swing. Under normal circumstances, with the feedback control, the oxygen sensor feedback voltage will be 0.45V at changing up and down, 10s in the number of feedback voltage changes should not be less than 8 times. If less than 8 times, then oxygen sensor feedback control system or not working properly because the surface of oxygen sensor are possible there is carbon deposition, so that lower sensitivity. In this regard, should be allowed to 2500r/min engine speed operation of about 2min, to clear the surface of the carbon deposition oxygen sensor, and then check the feedback voltage. If the removal of carbon deposition may change after the voltage meter pointer is still slow, then oxygen sensor damaged, or have computer feedback control circuit fault. 4) check whether the damaged oxygen sensor Unplug the oxygen sensor wiring harness plug, so that oxygen sensor is no longer connected with the computer, feedback control system is in a state ofopen-loop control. The multimeter voltage pen table file is directly related to oxygen sensor feedback voltage output terminal connected to the negative form of good Ground pen. Measurement of engine operation at the feedback voltage, the first intake pipe was torn off and then up at the mandatory crankcase ventilation hose vacuum tube or other artificially dilute the mixture to form, at the same time watch voltage meter, the pointer should be dropped readings. Was torn off and then connected to the pipeline, and then unplug the water temperature sensor connector, a 4-8KΩ in place of the resistance temperature sensor, the formation of artificially dense mixture, at the same time watch voltage meter, the indicator reading should be increased. Can also be used, or a sudden release the accelerator pedal down approach to change the concentration of the mixture, in sudden pedal down to accelerate, the mixture变浓, feedback voltage should be increased; sudden release when the accelerator pedal,mixed gas-thinning, feedback voltage should be decreased. If the oxygen sensor feedback voltage without the above changes show that the oxygen sensor has been damaged. In addition, the titanium dioxide-type oxygen sensor using the above method at the time, if a good oxygen sensor output voltage to 2.5V as the center should be up and down fluctuations. Otherwise, the sensor can be removed and exposed to the air, cooling the resistance value after the measurement. If a large resistance value that sensor is ok, or should replace the sensor. 5) oxygen sensor to check the color appearance Removed from the exhaust pipe on oxygen sensors, sensors to check whether the shell to plug up the vents, ceramic core whether or not broken. If damaged, replace the oxygen sensor should be. By observing the top part of the oxygen sensor can also determine the color breakdown:①light gray top: This is the normal color of the oxygen sensor; ②white top: pollution from silicon, oxygen sensor must be replaced at this time; ③brown top: pollution by lead, if serious, we must replace the oxygen sensor; ④black top: caused by carbon deposition, carbon deposition in the exclusion of engine failure, the general oxygen sensor can automatically clear up the accumulatedcarbon. Conclusion: for energy conservation and the prevention of pollution from motor vehicles, most developed countries in the West aerobic sensors installed on my car is loaded oxygen sensor must be used. China's automobile industry with foreign countries, one of the main gap, but also in automotive sensors. Therefore, we can come to promote the use of oxygen sensor is very optimistic about the prospects.汽车氧传感器的常见故障及检查汽车行业是目前在国际上应用传感器最大的市场之一,而氧传感器申报的专利数,居汽车传感器的首位。
Ultrasonic ranging system designPublication title: Sensor Review. Bradford: 1993.Vol.ABSTRACT: Ultrasonic ranging technology has wide using worth in many fields, such as the industrial locale, vehicle navigation and sonar engineering. Now it has been used in level measurement, self-guided autonomous vehicles, fieldwork robots automotive navigation, air and underwater target detection, identification, location and so on. So there is an important practicing meaning to learn the ranging theory and ways deeply. To improve the precision of the ultrasonic ranging system in hand, satisfy the request of the engineering personnel for the ranging precision, the bound and the usage, a portable ultrasonic ranging system based on the single chip processor was developed.Keywords: Ultrasound, Ranging System, Single Chip Processor1. IntroductiveWith the development of science and technology, the improvement of people’s standard of living, speeding up the development and construction of the city. Urban drainage system have greatly developed their situation is construction improving. However, due to historical reasons many unpredictable factors in the synthesis of her time, the city drainage system. In particular drainage system often lags behind urban construction. Therefore, there are often good building excavation has been building facilities to upgrade the drainage system phenomenon. It brought to the city sewage, and it is clear to the city sewage and drainage culvert in the sewage treatment system.Co mfort is very important to people’s lives. Mobile robots designed to clear the drainage culvert and the automatic control system Free sewage culvert clear guarantee robots, the robot is designed to clear the culvert sewage to the core. Control system is the core component of the development of ultrasonic range finder. Therefore, it is very important to design a good ultrasonic range finder.2. A principle of ultrasonic distance measurementThe application of AT89C51:SCM is a major piece of computer components are integrated into the chip micro-computer. It is a multi-interface and counting on the micro-controller integration, and intelligence products are widely used in industrial automation. and MCS-51 microcontroller is a typical and representative.Microcontrollers are used in a multitude of commercial applications such as modems, motor-control systems, air conditioner control systems, automotive engine and among others. The high processing speed and enhanced peripheral set of these microcontrollers make them suitable for such high-speed event-based applications. However, these critical application domains also require that these microcontrollers are highly reliable. The high reliability and low market risks can be ensured by a robust testing process and a proper tools environment for the validation of these microcontrollers both at the component and at the system level. Intel Plaform Engineering department developed an object-oriented multi-threaded test environment for the validation of its AT89C51 automotive microcontrollers. The goals of this environment was not only to provide a robust testing environment for the AT89C51 automotive microcontrollers, but to develop an environment which can be easily extended and reused for the validation of several other future microcontrollers. The environment was developed in conjunction with Microsoft Foundation Classes(AT89C51).1.1 Features* Compatible with MCS-51 Products* 2Kbytes of Reprogrammable Flash MemoryEndurance: 1,000Write/Erase Cycles* 2.7V to 6V Operating Range* Fully Static operation: 0Hz to 24MHz* Two-level program memory lock* 128x8-bit internal RAM* 15programmable I/O lines* Two 16-bit timer/counters* Six interrupt sources*Programmable serial UART channel* Direct LED drive output* On-chip analog comparator* Low power idle and power down modes1.2 DescriptionThe AT89C2051 is a low-voltage, high-performance CMOS 8-bit microcomputer with 2Kbytes of flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high density nonvolatile memory technology and is compatible with the industry standard MCS-51 instruction set and pinout. By combining a versatile 8-bit CPU with flash on a monolithic chip, the Atmel AT89C2051 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications.The AT89C2051 provides the following standard features: 2Kbytes of flash,128bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator and clock circuitry. In addition, the AT89C2051 is designed with static logicfor operation down to zero frequency and supports two software selectable power saving modes. The idle mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The power down mode saves the RAM contents but freezer the oscillator disabling all other chip functions until the next hardware reset.1.3 Pin Configuration1.4 Pin DescriptionVCC Supply voltage.GND Ground.Prot 1Prot 1 is an 8-bit bidirectional I/O port. Port pins P1.2 to P1.7 provide internal pullups. P1.0 and P1.1 require external pullups. P1.0 and P1.1 also serve as the positive input (AIN0) and the negative input (AIN1), respectively, of the on-chip precision analog comparator. The port 1 output buffers can sink 20mA and can drive LED displays directly. When 1s are written to port 1 pins, they can be used as inputs. When pins P1.2 to P1.7 are used as input and are externally pulled low, they will source current (IIL) because of the internal pullups.Port 3Port 3 pins P3.0 to P3.5, P3.7 are seven bidirectional I/O pins with internal pullups. P3.6 is hard-wired as an input to the output of the on-chip comparator and is not accessible as a general purpose I/O pin. The port 3 output buffers can sink 20mA. When 1s are written to port 3 pins they are pulled high by the internal pullups and can be used as inputs. As inputs, port 3 pins that are externally being pulled low will source current (IIL) because of the pullups.Port 3 also serves the functions of various special features of the AT89C2051 as listed below.1.5 Programming the FlashThe AT89C2051 is shipped with the 2 Kbytes of on-chip PEROM code memory array in the erased state (i.e., contents=FFH) and ready to be programmed. The code memory array is programmed one byte at a time. Once the array is programmed, to re-program any non-blank byte, the entire memory array needs to be erased electrically.Internal address counter: the AT89C2051 contains an internal PEROM address counter which is always reset to 000H on the rising edge of RST and is advanced applying a positive going pulse to pin XTAL1.Programming algorithm: to program the AT89C2051, the following sequence is recommended.1. power-up sequence:Apply power between VCC and GND pins Set RST and XTAL1 to GNDWith all other pins floating , wait for greater than 10 milliseconds2. Set pin RST to ‘H’ set pin P3.2 to ‘H’3. Apply the appropriate combination of ‘H’ or ‘L’ logic to pins P3.3, P3.4, P3.5,P3.7 to select one of the programming operations shown in the PEROM programming modes table.To program and Verify the Array:4. Apply data for code byte at location 000H to P1.0 to P1.7.5.Raise RST to 12V to enable programming.5. Pulse P3.2 once to program a byte in the PEROM array or the lock bits. The byte-write cycle is self-timed and typically takes 1.2ms.6. To verify the programmed data, lower RST from 12V to logic ‘H’ level and set pins P3.3 to P3.7 to the appropriate levels. Output data can be read at the port P1 pins.7. To program a byte at the next address location, pulse XTAL1 pin once to advance the internal address counter. Apply new data to the port P1 pins.8. Repeat steps 5 through 8, changing data and advancing the address counter for the entire 2 Kbytes array or until the end of the object file is reached.9. Power-off sequence: set XTAL1 to ‘L’ set RST to ‘L’Float all other I/O pins Turn VCC power off2.1 The principle of piezoelectric ultrasonic generatorPiezoelectric ultrasonic generator is the use of piezoelectric crystal resonators to work. Ultrasonic generator, the internal structure as shown, it has two piezoelectric chip and a resonance plate. When it’s two plus pulse signal, the frequency equal to the intrinsic piezoelectric oscillation frequency chip, the chip will happen piezoelectric resonance, and promote the development of plate vibration resonance, ultrasound is generated. Conversely, it will be for vibration suppression of piezoelectric chip, the mechanical energy is converted to electrical signals, then it becomes the ultrasonic receiver.The traditional way to determine the moment of the echo’s arrival is based on thresholding the received signal with a fixed reference. The threshold is chosen well above the noise level, whereas the moment of arrival of an echo is defined as the first moment the echo signal surpasses that threshold. The intensity of an echo reflecting from an object strongly depends on the object’s nature, size and distance from the sensor. Further, the time interval from the echo’s starting point to the moment when it surpasses the threshold changes with the intensity of the echo. As a consequence, a considerable error may occur even two echoes with different intensities arriving exactly at the same time will surpass the threshold at different moments. The stronger one will surpass the threshold earlier than the weaker, so it will be considered as belonging to a nearer object.2.2 The principle of ultrasonic distance measurementUltrasonic transmitter in a direction to launch ultrasound, in the moment to launch the beginning of time at the same time, the spread of ultrasound in the air, obstacles on his way to return immediately, the ultrasonic reflected wave received by the receiverimmediately stop the clock. Ultrasound in the air as the propagation velocity of 340m/s, according to the timer records the time t, we can calculate the distance between the launch distance barrier(s), that is: s=340t / 23. Ultrasonic Ranging System for the Second Circuit DesignSystem is characterized by single-chip microcomputer to control the use of ultrasonic transmitter and ultrasonic receiver since the launch from time to time, single-chip selection of 875, economic-to-use, and the chip has 4K of ROM, to facilitate programming.3.1 40 kHz ultrasonic pulse generated with the launchRanging system using the ultrasonic sensor of piezoelectric ceramic sensorsUCM40, its operating voltage of the pulse signal is 40kHz, which by the single-chip implementation of the following procedures to generate.puzel: mov 14h, # 12h; ultrasonic firing continued 200msHere: cpl p1.0; output 40kHz square wavenop;nop;nop;djnz 14h, here;retRanging in front of single-chip termination circuit P1.0 input port, single chip implementation of the above procedure, the P1.0 port in a 40kHz pulse output signal, after amplification transistor T, the drive to launch the first ultrasonic UCM40T, issued 40kHz ultrasonic pulse, and the continued launch of 200ms. Ranging the right and the left side of the circuit, respectively, then input port P1.1 and P1.2, the working principle and circuit in front of the same location.3.2 Reception and processing of ultrasonicUsed to receive the first launch of the first pair UCM40R, the ultrasonic pulse modulation signal into an alternating voltage, the op-amp amplification IC1A and after polarization IC1B to IC2. IC2 is locked loop with audio decoder chip LM567, internal voltage-controlled oscillator center frequency of f0=1/1.1R8C3, capacitor C4 determinetheir target bandwidth. R8-conditioning in the launch of the high jump 8 feet into a low-level, as interrupt request signals to the single-chip processing.Ranging in front of single-chip termination circuit output port INT0 interrupt the highest priority, right or left location of the output circuit with output gate IC3A access INT1 port single-chip, while single-chip P1.3 and P1.4 received input IC3A, interrupted by the process to identify the source of inquiry to deal with, interrupt priority level for the first left right after. Part of the source code is as follows:Receivel: push pswpush accclr ex1; related external interrupt 1jnb p1.1, right; P1.1 pin to 0, ranging from right to interrupt service routine circuitjnb p1.2, left; P1.2 pin to 0, to the left ranging circuit interrupt service routinereturn: SETB EX1; open external interrupt 1pop accpop pswretiright: …; right location entrance circuit interrupt service routineAjmp Returnleft: …; left ranging entrance circuit interrupt service routineAjmp Return3.3 The calculation of ultrasonic propagation timeWhen you start firing at the same time start the single-chip circuitry within the timer T0, the use of timer counting function records the time and the launch of ultrasonic reflected wave received time. When you receive the ultrasonic reflected wave, the receiver circuit output a negative jump in the end of INT0 or INT1 interrupt request generates a signal, single-chip microcomputer in response to external interrupt request, the implementation of the external interrupt service subroutine, read the time difference, calculating the distance. Some of its source code is as follows:RECEIVE0: PUSH PSWPUSH ACCCLR EX0; related external interrupt 0MOV R7, TH0; read the time valueMOV R6, TL0CLR CMOV A, R6SUBB A, #0BBH; calculate the time differenceMOV 31H, A; storage resultsMOV A, R7SUBB A, # 3CHMOV 30H, ASETB EX0; open external interrupt 0\POP ACCPOP PSWRETIFor a flat target, a distance measurement consists of two phases: a coarse measurement and a fine measurement:Step 1: Transmission of one pulse train to produce a simple ultrasonic wave.Step 2: Changing the gain of both echo amplifiers according to equation, until the echo is detected.Step 3: Detection of the amplitudes and zero-crossing times of both echoes.Step 4: Setting the gains of both echo amplifiers to normalize the output at, say 3 volts. Setting the period of the next pulses according to the: period of echoes. Setting the time window according to the data of step 2.Step 5: Sending two pulse trains to produce an interfered wave. Testing the zero-crossing times and amplitudes of the echoes. If phase inversion occurs in the echo, determine to otherwise calculate to by interpolation using the amplitudes near the trough. Derive t sub m1 and t sub m2.Step 6: Calculation of the distance y using equation.4、The ultrasonic ranging system software designSoftware is divided into two parts, the main program and interrupt service routine. Completion of the work of the main program is initialized, each sequence of ultrasonic transmitting and receiving control.Interrupt service routines from time to time to complete three of the rotation direction of ultrasonic launch, the main external interrupt service subroutine to read the value of completion time, distance calculation, the results of the output and so on.5、ConclusionsRequired measuring range of 30cm-200cm objects inside the plane to do a number of measurements found that the maximum error is 0.5cm, and good reproducibility. Single-chip design can be seen on the ultrasonic ranging system has a hardware structure is simple, reliable, small features such as measurement error. Therefore, it can be used not only for mobile robot can be used in other detection system.Thoughts: As for why the receiver do not have the transistor amplifier circuit, because the magnification well, integrated amplifier, but also with automatic gain control level, magnification to 76dB, the center frequency is 38k to 40k, is exactly resonant ultrasonic sensors frequency.6、Parking sensor6.1 Parking sensor introductionReversing radar, full name is "reversing the anti-collision radar, also known as" parking assist device, car parking or reversing the safety of assistive devices, ultrasonic sensors(commonly known as probes), controls and displays (or buzzer)and other components. To inform the driver around the obstacle to the sound or a moreintuitive display to lift the driver parking, reversing and start the vehicle around tovisit the distress caused by, and to help the driver to remove the vision deadends and blurred vision defects and improve driving safety.6.2 Reversing radar detection principleReversing radar, according to high-speed flight of the bats in thenight, not collided with any obstacle principles of design anddevelopment. Probe mounted on the rear bumper, according to different price and brand, the probe only ranging from two, three, four, six, eight,respectively, pipe around. The probe radiation, 45-degree angle up and downabout the search target. The greatest advantage is to explore lower than the bumper of the driver from the rear window is difficult to see obstacles, and the police, suchas flower beds, children playing in the squatting on the car.Display parking sensor installed in the rear view mirror, it constantlyremind drivers to car distance behindthe object distance to the dangerous distance, the buzzer starts singing, allow the driver to stop. When the gear lever linked into reverse gear, reversing radar, auto-start the work, the working range of 0.3 to 2.0 meters, so stop when the driver was very practical. Reversing radar is equivalent to an ultrasound probe for ultrasonic probe can be divided into two categories: First, Electrical, ultrasonic, the second is to use mechanical means to produce ultrasound, in view of the more commonly used piezoelectric ultrasonic generator, it has two power chips and a soundingboard, plus apulse signal when the poles, its frequency equal to the intrinsic oscillation frequency of the piezoelectric pressure chip will be resonant and drivenby the vibration of the sounding board, the mechanical energy into electrical signal, which became the ultrasonic probe works. In order to better study Ultrasonic and use up, people have to design and manufacture of ultrasonic sound, the ultrasonic probe tobe used in the use of car parking sensor. With this principle in a non-contactdetection technology for distance measurement is simple, convenient and rapid, easyto do real-time control, distance accuracy of practical industrial requirements. Parking sensor for ranging send out ultrasonic signal at a givenmoment, and shot in the face of the measured object back to the signal wave, reversing radar receiver to use statistics in the ultrasonic signal from the transmitter to receive echo signals calculate the propagation velocity in the medium, which can calculate the distance of the probe and to detect objects.6.3 Reversing radar functionality and performanceParking sensor can be divided into the LCD distance display, audible alarm, and azimuth directions, voice prompts, automatic probe detection function is complete, reversing radar distance, audible alarm, position-indicating function. A good performance reversing radar, its main properties include: (1) sensitivity, whether theresponse fast enough when there is an obstacle. (2) the existence of blind spots. (3) detection distance range.6.4 Each part of the roleReversing radar has the following effects: (1) ultrasonic sensor: used tolaunch and receive ultrasonic signals, ultrasonic sensors canmeasure distance. (2) host: after the launch of the sine wave pulse to the ultrasonic sensors, and process the received signal, to calculate the distance value, the data and monitor communication. (3) display or abuzzer: the receivinghost from the data, and display the distance value and provide differentlevels according to the distance from the alarm sound.6.5 Cautions1, the installation height: general ground: car before the installation of 45 ~55: 50 ~ 65cmcar after installation. 2, regular cleaningof the probe to prevent the fill. 3, do not use the hardstuff the probe surface cover will produce false positives or ranging allowed toprobe surface coverage, such as mud. 4, winter to avoid freezing. 5, 6 / 8 probe reversing radar before and after the probe is not free to swap may cause the ChangMing false positive problem. 6, note that the probe mounting orientation, in accordance with UP installation upward. 7, the probe is not recommended to install sheetmetal, sheet metal vibration will cause the probe resonance, resulting in false positives.超声测距系统设计原文出处:传感器文摘布拉福德:1993年超声测距技术在工业现场、车辆导航、水声工程等领域具有广泛的应用价值,目前已应用于物位测量、机器人自动导航以及空气中与水下的目标探测、识别、定位等场合。
英文资料SuspensionSuspension is the term given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. Suspension systems serve a dual purpose –contributing to the car's roadholding/handling and braking for good active safety and driving pleasure, and keeping vehicle occupants comfortable and reasonably well isolated from road noise, bumps, and vibrations,etc. These goals are generally at odds, so the tuning of suspensions involves finding the right compromise. It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, because all the forces acting on the vehicle do so through the contact patches of the tires. The suspension also protects the vehicle itself and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different.Leaf springs have been around since the early Egyptians.Ancient military engineers used leaf springs in the form of bows to power their siege engines, with little success at first. The use of leaf springs in catapults was later refined and made to work years later. Springs were not only made of metal, a sturdy tree branch could be used as a spring, such as with a bow.Horse drawn vehiclesBy the early 19th century most British horse carriages were equipped with springs; wooden springs in the case of light one-horse vehicles to avoid taxation, and steel springs in larger vehicles. These were made of low-carbon steel and usually took the form of multiple layer leaf springs.[1]The British steel springs were not well suited for use on America's rough roads of the time, and could even cause coaches to collapse if cornered too fast. In the 1820s, the Abbot Downing Company of Concord, New Hampshire developed a system whereby the bodies of stagecoaches were supported on leather straps called "thoroughbraces", which gave a swinging motion instead of the jolting up and down of a spring suspension (the stagecoach itself was sometimes called a "thoroughbrace")AutomobilesAutomobiles were initially developed as self-propelled versions of horse drawn vehicles. However, horse drawn vehicles had been designed for relatively slow speeds and their suspension was not well suited to the higher speeds permitted by the internal combustion engine.In 1903 Mors of Germany first fitted an automobile with shock absorbers. In 1920 Leyland used torsion bars in a suspension system. In 1922 independent front suspension was pioneered on the Lancia Lambda and became more common in mass market cars from 1932.[2]Important propertiesSpring rateThe spring rate (or suspension rate) is a component in setting the vehicle's ride height or its location in the suspension stroke. Vehicles which carry heavy loads will often have heavier springs to compensate for the additional weight that would otherwise collapse a vehicle to the bottom of its travel (stroke). Heavier springs are also used in performance applications where the loading conditions experienced are more extreme. Springs that are too hard or too soft cause the suspension to become ineffective because they fail to properly isolate the vehicle from the road. Vehicles that commonly experience suspension loads heavier than normal have heavy or hard springs with a spring rate close to the upper limit for that vehicle's weight. This allows the vehicle to perform properly under a heavy load when control is limited by the inertia of the load. Riding in an empty truck used for carrying loads can be uncomfortable for passengers because of its high spring rate relative to the weight of the vehicle. A race car would also be described as having heavy springs and would also be uncomfortably bumpy. However, even though we say they both have heavy springs, the actual spring rates for a 2000 lb race car and a 10,000 lb truck are very different. A luxury car, taxi, or passenger bus would be described as having soft springs. Vehicles with worn out or damaged springs ride lower to the ground which reduces the overall amount of compression available to the suspension and increases the amount of body lean. Performance vehicles can sometimes have spring rate requirements other than vehicle weight and load.Mathematics of the spring rateSpring rate is a ratio used to measure how resistant a spring is to being compressed or expanded during the spring's deflection. The magnitude of the spring force increases as deflection increases according to Hooke's Law. Briefly, this can be stated aswhereF is the force the spring exertsk is the spring rate of the spring.x is the displacement from equilibrium length i.e. the length at which the spring is neither compressed or stretched.Spring rate is confined to a narrow interval by the weight of the vehicle,load the vehicle will carry, and to a lesser extent by suspension geometry and performance desires.Spring rates typically have units of N/mm (or lbf/in). An example of a linear spring rate is 500 lbf/in. For every inch the spring is compressed, it exerts 500 lbf. Anon-linear spring rate is one for which the relation between the spring's compression and the force exerted cannot be fitted adequately to a linear model. For example, the first inch exerts 500 lbf force, the second inch exerts an additional 550 lbf (for a total of 1050 lbf), the third inch exerts another 600 lbf (for a total of 1650 lbf). In contrast a 500 lbf/in linear spring compressed to 3 inches will only exert 1500 lbf.The spring rate of a coil spring may be calculated by a simple algebraic equation or it may be measured in a spring testing machine. The spring constant k can be calculated as follows:where d is the wire diameter, G is the spring's shear modulus (e.g., about 12,000,000 lbf/in² or 80 GPa for steel), and N is the number of wraps and D is the diameter of the coil.Wheel rateWheel rate is the effective spring rate when measured at the wheel. This is as opposed to simply measuring the spring rate alone.Wheel rate is usually equal to or considerably less than the spring rate. Commonly, springs are mounted on control arms, swing arms or some other pivoting suspension member. Consider the example above where the spring rate was calculated to be500 lbs/inch, if you were to move the wheel 1 inch (without moving the car), the spring more than likely compresses a smaller amount. Lets assume the spring moved 0.75 inches, the lever arm ratio would be 0.75 to 1. The wheel rate is calculated by taking the square of the ratio (0.5625) times the spring rate. Squaring the ratio is because the ratio has two effects on the wheel rate. The ratio applies to both the force and distance traveled.Wheel rate on independent suspension is fairly straight-forward. However, special consideration must be taken with some non-independent suspension designs. Take the case of the straight axle. When viewed from the front or rear, the wheel rate can be measured by the means above. Yet because the wheels are not independent, when viewed from the side under acceleration or braking the pivot point is at infinity (because both wheels have moved) and the spring is directly inline with the wheel contact patch. The result is often that the effective wheel rate under cornering is different from what it is under acceleration and braking. This variation in wheel rate may be minimized by locating the spring as close to the wheel as possible.Roll couple percentageRoll couple percentage is the effective wheel rates, in roll, of each axle of the vehicle just as a ratio of the vehicle's total roll rate. Roll Couple Percentage is critical in accurately balancing the handling of a vehicle. It is commonly adjusted through the use of anti-roll bars, but can also be changed through the use of different springs.A vehicle with a roll couple percentage of 70% will transfer 70% of its sprung weight transfer at the front of the vehicle during cornering. This is also commonly known as "Total Lateral Load Transfer Distribution" or "TLLTD".Weight transferWeight transfer during cornering, acceleration or braking is usually calculated per individual wheel and compared with the static weights for the same wheels.The total amount of weight transfer is only affected by 4 factors: the distance between wheel centers (wheelbase in the case of braking, or track width in the case of cornering) the height of the center of gravity, the mass of the vehicle, and the amount of acceleration experienced.The speed at which weight transfer occurs as well as through which components it transfers is complex and is determined by many factors including but not limited to roll center height, spring and damper rates, anti-roll bar stiffness and the kinematic design of the suspension links.Unsprung weight transferUnsprung weight transfer is calculated based on the weight of the vehicle's components that are not supported by the springs. This includes tires, wheels, brakes, spindles, half the control arm's weight and other components. These components are then (for calculation purposes) assumed to be connected to a vehicle with zero sprung weight. They are then put through the same dynamic loads. The weight transfer for cornering in the front would be equal to the total unsprung front weight times theG-Force times the front unsprung center of gravity height divided by the front track width. The same is true for the rear.Suspension typeDependent suspensions include:∙Satchell link∙Panhard rod∙Watt's linkage∙WOBLink∙Mumford linkage∙Live axle∙Twist beam∙Beam axle∙leaf springs used for location (transverse or longitudinal)The variety of independent systems is greater and includes:∙Swing axle∙Sliding pillar∙MacPherson strut/Chapman strut∙Upper and lower A-arm (double wishbone)∙multi-link suspension∙semi-trailing arm suspension∙swinging arm∙leaf springsArmoured fighting vehicle suspensionMilitary AFVs, including tanks, have specialized suspension requirements. They can weigh more than seventy tons and are required to move at high speed over very rough ground. Their suspension components must be protected from land mines and antitank weapons. Tracked AFVs can have as many as nine road wheels on each side. Many wheeled AFVs have six or eight wheels, to help them ride over rough and soft ground. The earliest tanks of the Great War had fixed suspensions—with no movement whatsoever. This unsatisfactory situation was improved with leaf spring suspensions adopted from agricultural machinery, but even these had very limited travel. Speeds increased due to more powerful engines, and the quality of ride had to be improved. In the 1930s, the Christie suspension was developed, which allowed the use of coil springs inside a vehicle's armoured hull, by redirecting the direction of travel using a bell crank. Horstmann suspension was a variation which used a combination of bell crank and exterior coil springs, in use from the 1930s to the 1990s.By the Second World War the other common type was torsion-bar suspension, getting spring force from twisting bars inside the hull—this had less travel than the Christie type, but was significantly more compact, allowing the installation of larger turret rings and heavier main armament. The torsion-bar suspension, sometimes including shock absorbers, has been the dominant heavy armored vehicle suspension since the Second World War.中文翻译悬吊系统(亦称悬挂系统或悬载系统)是描述一种由弹簧、减震筒和连杆所构成的车用系统,用于连接车辆与其车轮。
外文文献原稿和译文原稿A New Type Car -- Hybrid Electric VehicleWith skyrocketing fuel prices and changes in weather patterns, many car manufacturers claimed to develop the kind of vehicles that will increase the mileage and reduce the emissions. Hybrid car is a kind of vehicle which can meet above requirements. A hybrid car features a small fuel-efficient gas engine combined with an electric motor that assists the engine.The reasons of building such a complicated machine are twofold: to reduce tailpipe emissions and to improve mileage. Firstly, hybrid cars are good for the environment. They can reduce smog by 90 percent and they use far less gasoline than conventional cars. Meanwhile, hybrid cars burn less gasoline per mile, so they release fewer greenhouse gases. Secondly, hybrid cars are economical. Hybrid cars, which run on gas and electricity, can get up to 55 to 60 miles per gallon in city driving, while a typical SUV might use three times as much gas for the same distance! There are three reasons can mainly account for that: 1) Hybrid engines are much smaller than those on conventional cars. A hybrid car engine is to accommodate the 99% of driving time when a car is not going up hills or accelerating quickly. When extra acceleration power is needed, it relies on the battery to provide additional force. 2) Hybrid gasoline engine can shut off when the car is stopped and run off their electric motor and battery.3) Hybrid cars often recover braking energy. Electric motors could take the lost kinetic energy in braking and use it to charge the battery. Furthermore, hybrids are better than all-electric cars because hybrid car batteries recharge as you drive so there is no need to plug in. Most electric cars need to be recharged every 50-100miles. Also, most electric cars cannot go faster than 50-60 mph, while hybrids can.Hybrid cars bridge the gap between electric and gasoline-powered cars by traveling further and driving faster and hybrid gas-electric cars are proving to be a feasible alternative at a time of high gas prices. So, in my opinion, hybrid cars will have a bright future.How Does Hybrid Electric Vehicle Work?You probably own a gasoline or diesel-engine car. You may have heard of electric vehicles too. A hybrid vehicle or hybrid electric vehicle (HEV) is a combination of both. Hybrid vehicles utilize two or more sources of energy for propulsion. In the case of HEVs, a combustion engine and an electric motor are used.How it works depends on the type of drive train it has. A hybrid vehicle can either have a parallel or series or parallel-series drive train.Parallel HybridThe parallel hybrid car has a gas tank, a combustion engine, transmission,electric motor, and batteries.A parallel hybrid is designed to run directly from either the combustion engine or the electric motor. It can run using both the engine and the motor. As a conventional vehicle, the parallel hybrid draws its power from the combustion engine which will then drive the transmission that turns the wheels. If it is using the electric motor, the car draws its power from the batteries. The energy from the batteries will then power the electric motor that drives the transmission and turns the wheel.Both the combustion engine and the electric motor are used at the same time during quick acceleration, on steep ascend, or when either the engine or the motor needs additional boost.Since the engine is directly connected to the wheels in a parallel drive train, it eliminates the inefficiency of converting mechanical energy into electrical energy and back. This makes a very effective vehicle to drive on the highway.Series HybridThe series hybrid car also has a gas tank, a combustion engine, transmission, electric motor, and batteries with the addition of the generator. The generator can be the electric motor or it can be another separate component.The series configuration is the simplest among the 3. The engine is not connected to the transmission rather it is connected to the electric motor. This means that the transmission can be driven only by the electric motor which draws its energy from the battery pack, the engine or the generator.A hybrid car with a series drive train is more suited for city driving conditions since the engine will not be subjected to the varying speed demands (stop, go, and idle) that contributes to fuel consumption.Series-Parallel HybridThe series-parallel configuration solves the individual problems of the parallel and series hybrid. By combining the 2 designs, the transmission can be directly connected to the engine or can be separated for optimum fuel consumption. The Toyota Prius and the Ford Escape Hybrid use this technology.Honda’s hybridFor those of you who have toyed with the idea of buying a hybrid but were discouraged by the price, you are not alone. In fact, despite the growing concern for the environment, not to mention the skyrocketing price of gas, hybrid cars still only represent a small percentage of global car sales, and a major reason for this is the cost.Hybrids are considered the wave of the future because they not only reduce emissions, addressing the issue of climate change, but they get great gas mileage, an important consideration with the current price of oil. It should be noted that hybrids can also improve the power of the engine, which compromises any advantages in fuel efficiency and emissions. Whatever the application, however, the technology makes the cars more expensive.Because of this, they are the vehicle of choice for only a small niche of people who can afford them, and they currently enjoy a special status amongst the image conscious celebrity-set. For most average consumers, however, they are not an option.That may soon change.Honda Motor Corporation, one of the largest car manufacturers in the world and a leader in fuel efficient technology, has unveiled it’s plan to introduce a low-cost hybrid by 2009. If they can pull it off, they hope to make the hybrid a more mainstream car that will be more appealing to the general public, with the ultimate goal of achieving greater sales and broader appeal than their current incarnation.This, of course, is making Detroit nervous, and may signal a need for American car makers to start making greener and more fuel efficient vehicles, something they could afford to ignore in the past because hybrid cars weren’t worth their attention (due to such a small market share) while gas-guzzling SUVs have such high profit margins.Honda, meanwhile, has had to confront a growing need to compete with Toyota, which has not only grown to be the world’s largest automaker, but makes the car that has become synonymous with the hybrid movement, the Prius. Honda is therefore faced with the seemingly insurmountable task of challenging Toyota’s dominance in the market.Concurrently, Toyota is racing to lower production costs on the Prius, as well, which would hopefully result in a lower cost to the consumer. All eyes are on a potentially favorable car buyers market in 2009.In the meantime, with even adamant global warming naysayers warming up (no pun intended) to the possibilities of an ecological disaster on the horizon, maybe it’s time that we got over our need to drive huge SUVs and start moderating our fuel consumption.Then again, as gas prices hovering around $4.00 and with no ceiling in sight, we may have little choice in the matter.Engine Operating PrinciplesMost automobile dngines are internal combustion, reciprocating 4-stroke gasoline engines, but other types have been used, including the diesel, the rotary ( Wankel ) , the 2-srtoke, and stratified charge.Reciprocating means up and down or banck and forth, It is the up and down action of a piston in the cylinder blick, or engine block. The blick is an iron or aluminum casting that contains engine cylinders and passges called water jackets for coolant circulation. The top of the block is covered with the cylinder head. Which forms the combustion chanber. The bottom of the block is covered with an oil pan or oil sump.Power is produced by the linear motion of a piston in a cylinder. However, this linear motion must be changed into rotary motion to turn the wheels of cars of trucks. The piston is attached to the top of a connecting rod by a pin, called a piston pin or wrist pin. The bottom of the connecting rod is attached to the crankshaft. The connecting rod transmits the up-and-down motion of the piston to the crankshaft, which changes it into rotary motion.The connecting rod is mounted on the crankshaft with large beaings called rodbearings. Similar bearings, called main bearings, are used to mount the crankshaft in the block. Shown in Fig. 1-1The diameter of the cylinder is called the engine bore. Displacement and compression ratio are two frequently used engine specifications. Displacement indicates engine size, and compression ratio compares the total cylinder volume to compression chamber volume.The term stroke is used to describe the movement of the iston within the cylinder, as well as the distance of piston travel. Depending on the type of engine the operating cycle may require either two or four strokes to complete. The 4-stroke engine is also called Otto cycle engine, in honor of the German engineer, Dr. Nikolaus Otto, who first applied the principle in 1876. In the 4-stroke engine, four strokes of the piston in the cylinder are required to complete one full operating cycle. Each stroke is named after the action it performs intake, compression, power, and exhaust in that order, shown in Fig1-2.1、Intake strokeAs the piston moves down, the vaporized mixture of fuel and air enters the cylinder through open intake valve. To obtain the maximum filling of the cylinder the intake valve opens about 10°before t.b.c., giving 20°overlap. The inlet valve remains open until some 50°after b.d.c. to take advantage of incoming mixture.2、 Compression strokeThe piston turns up, the intake valve closes, the mixture is compressed within the combustion chamber, while the pressure rise to about 1Mpa, depending on various factors including the compression ratio, throttle opening and engine speed. Near the top of the stroke the mixture is ignited by a spark which bridges the gap of the spark plug.3、 Power strokeThe expanding gases of combustion produces a rise in pressure of the gas to some 3.5Mpa, and the piston is forced down in the cylinder. The exhaust valve opens near the bottom of the stroke.4、Exhust strokeThe piston moves back up with the exhaust valve open some 50°before b.d.d., allowing the pressure within the cylinder to fall and to reduce ‘back’pressure on the piston during the exhaust stroke, and the burned gases are pushed out to prepare for the next intake stroke.The intake valve usually opens just before the exhaust stroke. This 4-stroke cycle is continuously repeared in every as long as the engineremains running.A 2-stroke engine also goes through four actions to complete one operating cycle.However, the intake and the compression actions are combined in one seroke, and the power and exhaust actions are combined in the other stroke. The term2-stroke cycle or 2-stroke is preferred to the term 2-cycle, which is really not accurate.In automobile engines, all pistons are attached to a single crankshaft. The more cylinders an engine has, the more power strokes produced for cach revolution. This means that an 8-cylinder engine runs more smoothly bdcause the power atrokes arecloser together in time and in degrees of engine rotation.The cylinders of multi-cylinder automotive engines arranged in one of three ways. 1、Inline engines use a single block of cylinder.Most 4-cylinder and any 6-cylinder engines are of this design. The cylinders do not have to be vertical. They can be inclined either side.2、V-type engines use two equal bands of cylinders, usually inclined 60degrees or 90degrees from the cach other. Most V-type engines have 6 or 8 cylinders, although V-4 and V-12 engines have been built.3、Horizontally opposed or pancake engines have two equal banks of cylinders 180degreeas apart. These space saving engine designs are often air-cooled, and are found in the Chevrolet Carvair, Porsches, Subaus, and V olkswagens. Subaus design is liquid cooled.Late-model V olkswagen vans use a liquid-cooled version of the air cooled VWhorizontally opposed engine.译文新型汽车----混合动力汽车在油价飞涨的今天,汽车制造商被要求发展一种排放低,行驶里程长的汽车。
Automotive MarketingFirst, the auto parts network management conceptAmerican auto parts of automobile fittings dealer Raymond is located in a suburban Atlanta, American and other accessories, this shop to shop and its characteristics, but is online transactions, and car accessories sales related services are available on the Internet. This distributior store of salespeople have extensive network of knowledge, they patiently helped no online trading experience of customer finish on the Internet. If the customer need, they also can be free of imparting knowledge of online transactions. In order to reflect the rapid and convenient online sales, they provide 24-hour services, if the customer questions, they always strive to reply in 15 minutes. The customer need, sitting at home before entering the store sells computer, then the website can complete all want to do, watch shop fittings, download the pictures, auto prices, orders, etc. Then, you can sit at home or in his own maintenance shop of door-to-door salesman received by car accessories.Online transaction does have many advantages. To save time, this is obvious. In this way, said dealers trade become a way to attract customers, people gradually accept it and approved. At the same time, the online trading reduced many expenses, including the staff, management, marketing, etc, and save the cost of expenses on auto parts price on the customer benefit.This is the foreign auto accessories sales of a networked management. This through the Internet and e-commerce fulfillment of our country, and online business, the auto parts marketing MVP has important significance. From the current situation of auto parts, auto sales network throughout the circulation of construction is not perfect, or in an internal network condition. The network Settings are mostly for enterprise internal coordination and daily management, instead of e-commerce.China's online accessories sales prospects from abroad, also can be the development of auto parts online sales of enlightenment. In the foreign auto accessories sales, how to do? "" zero kilometers sales How to provide the most satisfactory service to customers? With the Internet, these two problems can greatly alleviate. Now, especially developed countries around the world through the Internet to buy auto accessories are expanding quickly.Second, the auto parts network management advantagesOnline purchase of auto parts for car dealers and customers, whether for auto parts manufacturing enterprise, it is a good thing. First, for auto parts manufacturing enterprise, the Internet can more easily collect customers to buy auto parts in the process of the various issues, and timely information feedback to the auto parts manufacturing enterprises. According to the above analysis, the enterprise can produce customer purchase intention, thus producing according with market demand as the auto parts. This saves time and cost, and snatch market opportunities. Secondly, the use of Internet information and convenient services, manufacturing enterprises can promptly informed accessories vendors inventory and sales, thereby adjusting their production and auto parts allocation plan. Auto accessories vendors reduce inventory, accelerate the cash flow, obtained satisfactory returns. For users, they can through the Internet, like "menu" optional choose oneself need auto parts.The market information for auto parts manufacturing enterprise and the seller is important, and can be easily obtained through the Internet. Internet auto parts vendors canprovide customers to production enterprise of real-time field information. The demand of information can help to reduce automobile accessories sales production enterprise charges, which usually cost will account for auto parts price of around 15% final sales. If the promotion costs, the cost is higher proportion. In fact, the Internet can also play a role of advertising.Before that, the sellers of auto parts distribution has always sold in part, and another part of the poor. Money is part of the occupied fee is caused to sell the car accessories. Through the Internet, the production enterprises and vendors can be avoided in production and sales market sales bad auto parts. With the advent of the Internet and convenient service, not only saves time and cost, and more importantly, the Internet can cause a concept of change, auto parts manufacturing enterprise, distributors and customers to be stuck nearlier more.Third, China's automobile fittings network management development trendChina's auto accessories network management and e-commerce, has started to present development trend. Many of the current domestic large and medium-sized car repair enterprises established computer management system, realized the internal network. This covers the entire network maintenance services. To receive from business, dispatching material inspection. Computerized control can be made to understand the undertakings in real-time monitoring, which can form, and greatly improve the efficiency of the staff, more important is to replace manual accounting and management, strengthen accessories.Meanwhile, some large scale, the current operating performance good car accessories dealers also introduced a computerized management. Because of automotive products, so use variety of such management software, the personnel must be higher requirements after a period of training to mount guard. Such auto parts management network covers the whole process of operation. From the incoming, retail and wholesale price is determined according to the models, and such Numbers classified management, finally to do account settlement and delivery, and XiaoZhang. Chain-like management make better dealer has put the network management of the whole FenXiaoDian to it, formed a certain scale of network connection. Many automobile fittings all dealers from network management gained good returns. The most prominent feature is reflected in the commodity, through the network management allocations, can reach twice the result with half the effort.In addition, in recent years the old car accessories circulation system gradually broken, auto parts market, constantly mature vigorous development. Some far-sighted insight, the operator has felt the network era, and start a near the market network. Like changchun automobile fittings, west of Beijing automobile fittings, Shanghai auto parts market such as the city of virtual network construction and the development of the market for 2000. But the reality is that the network is quite childish, but certainly not realize online trading and service.With the quickening pace of "two", the personage inside course of study to commend "trinity" sales mode in the earth gradually. For example, in the choice of Shanghai general dealers, whether to have "trinity" sales ability to determine the object, such as a "trinity" whole car accessories sales mode is a microcosm of network flow field. Because it includes from truckload sale, spare parts supply and maintenance.Mention auto parts network management and e-commerce, somebody thinks, car accessories telephone shopping is actually e-commerce, because only communicationplatform between different, the operation is basically the same. Actually this kind of understanding is not accurate, phone business and e-commerce is more like Cousins, in many ways, phone business congenital deficiency. First, consumers from the phone in understanding the information is limited, can fully satisfy customer's requirements. Secondly, if advertisers, or printing accessories for customers, due to the directory of accessories sales, cost of printing more and more high, but slow renewal speed. In addition, on the telephone exchanges, due to the environment, voice, speaking, the influence of factors, make telephone service personnel difficulty and error rates increased. Just as phone business, management content in depth and breadth aspect further development will be limited.Fourth,Auto parts distribution system and network management of constructionAuto parts distribution system and network management of construction iis now a successful online trading tangible products such as books, audio and video products, clothing, etc., and auto parts as a certain scientific and technological content, some products are statemandatory standard industrial products, to achieve on-line transactions, compared with other industrial products, have their advantages, sellers and buyers as long as posted on the Internet and input information about auto parts, such as vehicles, cars, parts name, part number, manufacture, price, quantity, etc., you can sell online or purchase.To truly realize the concept of e-commerce online sales, buyers and sellers in addition to solving the "integrity" issues, but also must establish a complete set of efficient logistics distribution system.Speaking before the factors that limit development of electronic commerce, nothing more than a means of payment, security authentication, the real make up, will find car parts logistics and distribution system is the most difficult, the most facile, the most expensive one.Many auto parts e-commerce companies are trying to find the existing physical network, such as postal services, courier and even newspaper delivery company as a delivery system.However, a suitable auto parts distribution and e-commerce system should look like?The conditions of physical network can be transformed into an auto parts distribution system of e-commerce will be the lowest cost?Five, Auto parts network management is the only way for the development and reform of the road networkThe Chinese auto parts sales development should be appropriate for the situation in China, with Chinese characteristics, the way the Internet business. Indeed, the United States, network operators have achieved great success, but we can not ignore this brilliant behind the social basis of the United States strong material foundation. As early as 100 years ago, the U.S. has established a comprehensive road, rail, postal services, courier delivery system combining; today's society, Americans have been accustomed to "free currency trading." It can be said that today's Internet economy development in the United States should be a very natural result and is more than 200 years the United States as a free market economy based on natural product. Like a child to climb from the start with their bare hands, and then learn to walk, over time learned to run naturally. As the development of China, only two aspects of payment and delivery has become a fatal problem "bottleneck." How to combine the development of China's national conditions and characteristics of the Internet, be able to realistically do something practical auto parts network operators today is the development of priority. China'sauto parts e-commerce and enterprise network operators must follow the joint and it should be a very natural result is more than 200 years the United States as a free market economy based on natural product. Like a child to climb from the start with their bare hands, and then learn to walk, over time learned to run naturally. As the development of China, only two aspects of payment and distribution has become a fatal problem "bottleneck."How to combine the development of China's national conditions and characteristics of the Internet, Being able to realistically do something practical auto parts network operators today is the development of priority.汽车营销一、汽车配件网络化经营的概念美国汽车配件经销商雷蒙德的汽车配件店位于美国亚特兰大市的一个郊外,这个小店与别的配件店并无二致,但其特色是网上交易,任何与汽车配件销售相关的服务均可在互联网上实现。
Development of Integrated Motor Assist Hybrid System:Development of the ‘Insight’, a Personal Hybrid Coupe Kaoru Aoki, Shigetaka Kuroda, Shigemasa Kajiwara,Hiromitsu Sato and Yoshio YamamotoHonda R&D Co.,Ltd. Copyright ©2000 Society of Automotive Engineers, Inc.ABSTRACTThis paper presents the technical approach used to design and develop the powerplant for the Honda Insight, a new motor assist hybrid vehicle with an overall development objective of just half the fuel consumption of the current Civic over a wide range of driving conditions. Fuel consumption of 35km/L (Japanese 10-15 mode), and 3.4L/100km (98/69/EC) was realized. To achieve this, a new Integrated Motor Assist (IMA) hybrid power plant system was developed, incorporating many new technologies for packaging and integrating the motor assist system and for improving engine thermal efficiency. This was developed in combination with a new lightweight aluminum body with low aerodynamic resistance. Environmental performance goals also included the simultaneous achievement of low emissions (half the Japanese year 2000 standards, and half the EU2000 standards), high efficiency, and recyclability. Fullconsideration was also given to key consumer attributes, including crash safety performance, handling, and driving performance.1.INTRODUCTIONTo reduce the automobile’s impact on society and the environment requires that it be increasingly cleaner and more energy efficient. The issues of energy conservation, ambient air quality, and reduction in CO2 emissions are increasing raised as global environmental concerns. One solution for dealing with these issues is the hybrid automobile. Honda has developed and introduced to several major markets worldwide the Insight, a new generation of vehicle design. The Insight combines a hybrid power train with advanced body technology features to meet an overall goal of achieving the highest fuel economy practical.The hybrid power train is a motor assist parallel configuration, termed IMA for ‘Integrated Motor Assist’. This power train combines a highly efficient electric motor with a new small displacement VTEC engine, a lightweight aluminum body, and improved aerodynamics to realize 3.4L/100km (CO2:80g/km) on 98/69/EC fuel economy. Low emissions performance was also targeted with emission levels achieving the EU2000.In addition to recapturing deceleration energy, the integrated motor provides high torque assist during typical urban driving accelerations. This allows a significant reduction in engine displacement and higherengine efficiency. Sustained hill climbing performance and high speed cruising capability are assured by a power-toweight ratio of approximately 56kW per metric ton. New engine technology includes the application of a new VTEC (Variable valve Timing and valve lift, Electronic Control) cylinder head design promoting high efficiency and fast catalyst activation, and a new lean NOx catalyst system which promotes lean burn combustion and a reduction in emissions. Extensive friction and weight reducing features are also applied.2.DEVELOPMENT TARGETS AND CONCEPTDevelopment was aimed at the achievement of extremely low fuel consumption. We set a target of twice the fuel economy of the current production Civic, Honda’s representative high fuel economy car at 7.0 L/100km (93/116/ EC). As a result, the Insight has the lowest fuel consumption in the world, among gasoline passenger cars.Exhaust emission performance often tends to be sacrificed for the sake of low fuel consumption. However, we also decided to match the low emissions performance achieved by other mass production cars. Consideration was also given to recyclability (another important environmental issue), crash safety performance, and the basic car characteristics including handling and styling.Summarizing the above, our development targets were as follows:The best fuel consumption performance in the world∙Ultra-low exhaust emissions∙Superior recyclability∙The world's highest level of crash safety performance∙Advanced styling∙Practical features and responsive handling∙Comfortable two-seat configuration with personal utility space3.POLICIES FOR FUEL CONSUMPTION REDUCTIONIn order to establish the technical approach for achieving the fuel consumption target, we conducted a detailed analysis of the energy consumption of the base car, a Civic equipped with a 1.5 liter engine. We found that it was useful to divide the targeted efficiency gains roughly into thirds, as shown in Fig. 1, in order to achieve the low fuel consumption and numerous other above-mentioned goals. These divisions are as follows.∙Improvement of the heat efficiency of the engine itself∙Recovery of braking energy and employment of idle stop using a hybrid power plant∙Car body technologies including reduction of weight and reduced aerodynamic and rolling resistance.Figure 1. Target of double the fuel economy of CIVICAiming to establish a benchmark for 21st century automobile power trains, we developed this new Integrated Motor Assist power train. This power train simultaneously achieves both extremely low fuel consumption of 3.4L/100km, and low exhaust gas emission performance, befitting a next-generation car.This paper reports on the newly developed IMA system, including the lean burn engine, electric motor, power control unit, battery technology, and exhaust emission control technology used in the "Honda Insight". 4.AIM OF THE IMA SYSTEMWhile developing this next-generation IMA hybrid system, we incorporated as many currently achievable technologies and techniques as possible, in order to achieve the "world's lowest fuel consumption".The following four system development themes were established in order to meet this target.1.Recovery of deceleration energy2.Improvement of the efficiency of the enginee of idle stop system4.Reduction of power train size and weight5.OVERVIEW OF THE IMA SYSTEM5.1. SYSTEM CONFIGURATION –As shown in Fig. 2, the IMA system uses the engine as the main power source and an electric motor as an auxiliary power source when accelerating. Using a motor as an auxiliary power source simplifies the overall system and makes it possible to use a compact and lightweight motor, battery, and power control unit (PCU).Figure 2. IMA SystemA permanent magnet DC brushless motor is located between the engine and the transmission. When decelerating, the rate of deceleration is calculated for each gear and the PCU controls the motor to generate electricity (recover energy), which charges a nickel-metal hydride battery. When accelerating, the amount of auxiliary power provided (hereaftercalled "assist") is calculated from the throttle opening, engine parameters, and battery state of charge. The PCU controls the amount of current flowing from the battery to the drive motor5.2.RECOVERY OF DECELERATION ENERGY –Recoveringdeceleration energy through regeneration makes it possible tosupplement the engine’s output during acceleration and reduce theamount of fuel consumed. Reducing resistance due to runninglosses, including engine frictional losses, increases the availableenergy for regeneration. In particular, minimizing the enginedisplacement is an effective means of reducing friction. Enginedisplacement reduction also has several other benefits, such asweight reduction and increased thermal efficiency. The IMAsystem effectively increases the amount of regeneration duringdeceleration by optimizing the engine and transmissionspecifications.5.3.REDUCTION OF ENGINE DISPLACEMENT –Reducingengine displacement is a very important factor in improving fueleconomy of a hybrid drive train. However, modern automobileshave to perform over a wide dynamic range. Reducing thedisplacement is equivalent to lowering the basic performancecharacteristics of the car. As shown in the output characteristicsgraph in Fig. 3, the IMA system assists the engine in the low rpmrange by utilizing the hightorque performance characteristic of electric motors. The motor can increase overall toruque by over 50% in the lower rpm range used in normal driving. Output in the high rpm range is increased by using a Variable valve Timing and valve lift Electronic Control (VTEC) engine. Thus sufficient peak power is assured and makes it possible to use a new, small displacement 1.0 liter engine.Figure 3.Engine speed (rpm) Output performance of IMA SYSTEM Assist from the electric motor while accelerating is a very efficient means of reducing the amount of fuel consumed.5.4.ACHIEVING LEAN BURN ENGINE OPERATION –Assistfrom the electric motor, based upon the throttle opening, creates quite linear torque characteristics. This, in turn, improves driveability. In addition, motor assist is also provided undermoderate load conditions to broaden the lean-burn operating range, bringing out the full potential of the newly developed lean burn engine.5.5.IDLE STOP SYSTEM – Stopping the engine rather than idling atstops is also an effective means for reducing fuel consumption. In order to restart the engine with the minimum amount of fuel consumption, the engine is quickly cranked to 600 rpm or more by the hightorque integrated motor before ignition occurs, as shown in Fig. 4. This makes it possible to minimize the amount of fuel consumed, in addition to the fuel saved by not running the engine at idle.There are many issues to be considered when performing idle stop. These include judging the driver's intent to stop, preparing for the restart, providing a smooth feeling of deceleration, and minimizing vibration of the car body when the engine stops.Figure 4.Time (sec) The number of cranking in the engine startThis IMA system results in the achievement of both very quick restarts and exceptionally smooth starts.6.MOTOR ASSIST MECHANISM6.1. DEVELOPMENT OBJECTIVES –By limiting the IMA motor functions to assistance and regeneration, development themes were established to achieve the following two points.1.A simple and compact structure2.A system weight of 10% (80 kg) or less of the completed car weight 6.2. THIN PROFILE DC BRUSHLESS MOTOR – A thin and compact DC brushless motor with engine assist and energy regeneration functions was coupled to the engine crank-shaft (Fig. 5).Figure 5. Section view of MotorThis is a high efficiency, compact, and lightweight permanent magnet-type three-phase synchronous electric motor with a maximum output of 10 kW. In addition to developing technologies to reduce the weight and increase efficiency, we also aimed to make the motor as thinas possible in order to achieve a compact power train. Lost wax precision casting process was used for the rotor, rotating by bending coupled to the crankshaft. This achieves high strength and lighter weight (approximately -20%) compared with normal cast products. For the rotor magnets, further improvements were made to the neodymium-sintered magnets used in the HONDA EV PLUS, realizing approximately 8% greater torque density and improved heat resistance. This design also results in a motor structure that does not require a cooling system. A split stator structure with salient pole centralized windings was developed and used to reduce the motor axial width. A split stator was adopted to drive the rotor. This makes it possible to use the salient pole centralized windings, which are both more compact and efficient than the conventional coil wave winding method, as shown in Fig. 6. In addition, centralized distribution bus rings (Fig. 7) formed from copper sheets were used for the harness that supplies electricity to the coils on both sides of the stator. This results in an extremely compact and simple structure. These improvements achieve an extremely thin motor with a width of only 60 mm. This represents a 40% reduction in width compared to conventional technology.Wave winding Salient pole windingFigure 6. Compare of windingFigure 7. Cut view of Motor6.3. NICKEL-METAL HYDRIDE (NI-MH) BATTERY – A nickel-metal hydride battery is used to store and provide electrical energy for the motor assist. This is an advanced battery which has already achieved proven results in the high specific energy version used for the HONDA EV PLUS electric vehicle. The hybrid vehicle battery features stable output characteristics, regardless of the state-of-chargestatus. It is also extremely durable in this application. The battery pack has an integrated structure consisting of 20 modules, each having sixD-size cells connected in series, arranged in a lattice formation. These 120 1.2 V cells are all connected in series for a total battery pack voltage of 144 V.6.4. POWER CONTROL UNIT (PCU) –The PCU performs precise control of motor assist/regeneration and supplies power to the 12 V power source. It has built-in cooling functions, which give it a lightweight, efficient and compact structure. Significant weight reduction was achieved by integrating an air cooling system using highly efficient cooling fins and a magnesium heat sink case.The inverter for the drive motor, which is the most important component within the PCU, has switching elements integrated into a single module for generating the three-phase AC current. These were separate components on the EV PLUS. The drive circuit has been miniaturized and converted to an IC using high density integration. These improvements have resulted not only in significant weight reduction, but have also improved the power conversion efficiency. Further, using phase control to drive the motor at very high efficiencies reduces the amount of heat produced and makes it possible to use a lightweight and simple air-cooling system. (Fig. 8)Figure 8.Inverter Cut view of PCU Heat Sink case7.ENGINE7.1. DEVELOPMENT OBJECTIVES – The following four points were set as development themes in order to achieve low fuel consumption over a wide range of operating conditions.1.Improvement of thermal efficiency2.Reduction of mechanical losses (-10% compared with conventionaldesigns )3.Reduction of size and weight (lightest weight in its class)4. Achievement of half the EU2000 standards7.2.ENGINE OVERVIEW AND SPECIFICATIONS –The enginespecifications are shown in Table 1 and the main new features and their purposes are shown in Table 2.First, a displacement of approximately 1000 cm3 was considered optimal for this vehicle with the IMA system, so a 3-cylinder engine was selected to minimize combustion chamber surface-to-volume ratio andmechanical losses. (Fig. 9)7.3.FUEL CONSUMPTION – Engine displacement could be reduceconsiderably in the motor assist powertrain because of the motor assist enhancement of low rpm torque, and also VTEC for sufficient peak power output from the engine. A key feature of this engine is the significant improvement in combustion efficiency through lean burn technology. Technologies adopted to make this possible include new intake swirl ports, which enhance the swirl (mixture formation) inside the cylinders. A compact combustion chamber and a high compression ratio also help by improving the indicated heat efficiency. This result in significantly shorter combustion times compared to conventional lean burn engines, allowing combustion in a leaner range with a higher air-fuel ratio. This significantly improves the fuel consumption.The new high swirl ports and compact combustion chamber are evolutions based on conventional VTEC lean burn technology. In the conventional VTEC engine, swirl is produced by keeping one intake valve closed in low speed operating conditions. However, in this engine the intake valves and intake ports are arranged more vertically to produce strong eddies in the mixture flowing into the cylinders.The conventional VTEC configuration has the inlet and exhaust rocker arms each supported by a separate rocker shaft. The new VTEC mechanism shown in Fig.10 combines these into a single rocker shaft, thus realizing a significant reduction in size. In addition, it narrows the valve included angle from 46° to 30°, allowing a high swirl port shape and a very compact combustion chamber.Figure 9. Cutaway view of engineFigure 10. Section view of cylinder7.4.REDUCTION OF MECHANICAL LOSS –In addition toimprovement of the indicated heat efficiency, reduction of mechanical loss is also important to improve fuel economy. To achieve this, the following the low friction technologies were used.∙Roller coaxial VTEC mechanism∙Piston micro-dimple treatment∙Offset cylinder structure∙Low tension piston rings∙Carburized connecting rodsThe roller coaxial VTEC structure (Fig. 11) is an adaptation of technology used in the Honda S2000 (high output sportscar engine) to a single-cam VTEC mechanism. The camshaft drive loss was reduced by 70% using a needle roller bearing in the area where the rocker arm slides on the camshaft. In addition, simultaneous reduction in both weight and size were achieved by incorporating the VTEC switching piston into the roller bearing inner shaft.Piston micro-dimple treatment consists of treating the surface of the piston skirt to create a micro-dimple surface. This increases the oil film retention performance and can reduce friction by approximately 30% when lowfriction oil is used.Figure 11. Section view of Roller VTECThese effects resulted in the development of a 0W-20 grade low viscosity oil that complies with ILSAC standards. The friction reducing effects of super-low viscosity oil were measured by engine motoring. These measurement results are shown in Fig. 12. In the current technology engine, the HTHS viscosity at the limit friction value was approximately 2.5 mPas. Being used together with the advanced low friction engine, the limit value was lower than the current technology engineThese low friction technologies have vastly reduced the overall engine friction, as shown in Fig. 13. In total, they have realized a reduction in friction of 10% or more compared to a conventional 1.0 liter engine design .Figure 12. Limit in friction reductionFigure 13. Engine friction7.5.WEIGHT REDUCTION – The structure and materials of almostall parts in this engine have been reviewed with the aim of creating the lightest engine in the world in the 1.0 liter class. This weight reduction extends even to the "skeleton structure technology" and "materials technology" fields carburized connecting rods as used on the S2000 (high output sportscar engine). Carburization strength enhancement technology contributes greatly to increasing engine operational speed. We applied this strength enhancement technology to create a slim connecting rod design for the IMA engine. This resulted in a weight reduction of approximately 30% compared to conventional connecting rods.Most oil pans are made of steel plate or aluminum alloy. Conventionalmagnesium materials have had problems withstanding the high temperatures of engine oil. In contrast to conventional materials, which experience a significant drop in creep strength at 120°C or higher, we have developed a new magnesium oil pan (Fig. 14) which ensures sufficient creep strength up to 150°C.Figure 14. Magnesium Oil PanThis oil pan is fastened using steel bolts with aluminum washers to prevent galvanic corrosion. The oil pan weight is 35% lighter than an aluminum oil pan, for a reduction in weight that is comparable to the ratio between the specific masses of the two metals.In order to expand the application of plastic parts, plastic materials were adopted for the intake manifold, cylinder head cover, water pump pulley, and intake system parts. These changes brought the discrete dry weight of the engine to less than 60 kg, which is the lightest weight in the world for the 1.0 liter class.7.6.EXHAUST EMISSION PERFORMANCE –Technology forsimultaneously achieving both lean burn and low exhaust emissions was adopted in this engine, achieving a notable reduction in NOx emissions.Combustion was improved by putting the exhaust system to the rear of the engine (Fig. 15). In addition, the exhaust manifold was integrated with the cylinder head and a NOx adsorption catalyst which reduces NOx emissions during lean burn operation was also newly developed.Figure 15. Section view of emission system7.6.1. Integrated Exhaust Manifold and Cylinder Head – Conventional cylinder heads have independent exhaust ports for each cylinder and a separate exhaust manifold acts to converge these exhaust ports into a single port is then mounted to the head. However, the new head on the Insight has a structure which converges the exhaust ports into a single port inside the head, as shown in Fig. 16. This greatly reduces the weight. In addition, the small heat radiating surface area reduces the exhaust gas heat loss, thus enabling early catalyst activation.Figure 16. View of Head7.6.2. Lean NOx Catalyst – The catalyst system on the Insight combinesa conventional three-way catalyst with NOx adsorbing materials. The NOx conversion mechanism of the newly developed catalyst is shown in Fig. 17. The NOx in the exhaust gas is adsorbed and separated by the NOx adsorption action of the catalyst during lean engine operating conditions. Conventional three-way catalyst operation reduces part of the NOx to nitrogen and oxidizes most of the HC and CO to CO2 and H2O during lean operation. However, since the exhaust gas contains large amounts of oxygen, there is relatively little NOx reduction with the three-way catalyst and most of the NOx is stored on the surface of the adsorbing material. When the exhaust is held at the theoretical air fuel ratio (stoichiometry) or richer air-fuel ratio, the adsorbed NOx is reduced to nitrogen using HC and CO as reducing agents. The adsorbent is regenerated at the same time. Thus, NOx, HC and CO are effectively converted using the three-way catalytic action of the catalyst combined with the NOx adsorber.This type of catalyst exhibits superior conversion performance during both lean operation and stoichiometric operation by switching betweenlean and stoichiometry operating conditions. It is essential to create a regenerative atmosphere before the NOx adsorption capacity becomes overloaded. This catalyst directly adsorbs NOx during lean burn engine operation and the adsorbed NOx is then reduced and exhausted as harmless nitrogen (N2) during stoichiometric operation.Figure 17. Exhaust gas purification mechanismThis catalyst is characterized by the direct adsorption of NOx to the catalyst surface during lean operation. Adsorption on the catalyst surface, instead of absorption as a compound inside the surface, facilitates conversion during reduction and also provides superior durability at high temperatures. This adsorptive type catalyst reduces NOx emissions during lean burn operation to 1/10 the level of the conventional three-way catalyst. It should be noted that the adsorption and conversion performance of this type of catalyst is sensitive to sulfur levels in the fuel, as sulfur can compete for the active NOx adsorbing sites. As a conventional three-way catalyst has virtually no NOx reduction during lean-operation, the lean burn operating range typically has to be reducedto keep NOx emissions down. Use of an adsorptive type catalyst maintains the full lean burn range and improves fuel economy, even while reducing NOx.This vehicle can also satisfy the EU2000 standards, making this a highly efficient lean burn engine that complies with exhaust emissions standards throughout the world.8.CONCLUSIONThis paper presents a general overview of the recently developed motor assist hybrid powertrain, as well as a description of its various components and its output and emission performance. This hybrid power train simultaneously achieves ultra low fuel consumption and low exhaust emissions. It also achieves a compact, lightweight power train layout. We believe this system advances 21st century automotive technology toward regional and global environmental goals. REFERENCES1.Aoki, Kaoru, et al.: "Development an Integrated Motor Assist HybridSystem", JSAE No. 98-99 1612.Yamaguchi, Tetsuro: "CVT Control in the HONDA Hybrid 'IMA'",No. 9908 JSAE SYMPOSIUM, Latest Motive Power Transmission Technologies '99, p.37403.Ohno, Hiroshi, et al.: "Development of a NOx Adsorptive ReactionType Three-Way Catalyst", HONDA R&D Technical Review, V ol. 11No. 2 (October 1999), p.45-504.Fukuo, Koichi, et al.: "Development of the Ultra Low FuelConsumption Hybrid Car 'Insight'", HONDA R&D Technical Review, V ol. 11 No. 2 (October 1999), p.1-85.Hideki Tanaka, et al .: "The Effect of 0W-20 Low Viscosity EngineOil on Fuel Economy”, SAE Paper No.1999-01-3468,Fuels and Lubricants meeting and Exposition, Toronto, Ontario, Canada, October 1999.6.Aoki, Kaoru, et al.: "An Integrated Motor Assist Hybrid System",SAE Paper No.2000-01-2059, Government / Industry Meeting, Washington, D.C., USA。
05/31/07Competition and Regulation in the Korean Automobile Insurance IndustryWondon Lee*Soga Ewedemi*** Associate Professor of Insurance, Daegu University, South Koreawlee@daegu.ac.kr** Professor of Finance, Clarion University of Pennsylvania, U.S.Aewedemi@1. IntroductionThe Korean property and liability insurance industry had assets of US$49 billion and direct premiums written of US$25 billion in 2005, which was the second largest market in Asia and 10th in the world (Swiss Re, 2006). Automobile insurance accounted for 35.2% of the total premiums written, which is the important business line in the Korean property and liability insurance industry.1Since the monopolized market was opened to all the property and liability insurance companies in 1983,2the average growth rate of direct premium is over 18%. This rapid growth rate is attributed mainly to the dramatic increase in automobile usage and compulsory automobile liability insurance.3However, automobile insurance has not been a profitable business since the advent of competition in the market in 1983. During 23 fiscal years including year 2005 the automobile insurance industry experienced underwriting profits only two times in 1997 and 1998. Although underwriting losses have been totally or partially offset by investment profits, the industry has been believed to experience chronic operating losses.4The huge aggregate losses have been based on complaints about a strict government regulation and demands for changes and improvements in the regulation, including increases in premium (the price of insurance). In fact the history of the Korean automobile insurance industry is the history of deregulation on the industry. However, in spite of the series of deregulation the situation has not been much improved.The continual unsatisfactory performance could be ascribed to the more fundamental problems in this industry. Unfortunately it is hard to find more thorough study and analysis to find the fundamental problems about the automobile insurance industry in Korea. In this paper, we extensively examine the Korean automobile insurance industry in the context of the1In 2005Korean property-liability insurance statistics shows that the share of direct premium of long-term insurance is 47.9%. However, long-term insurance is simply a product in which an assumed interest rate is used for rate-making and of which insurance period is usually greater than or equal to 3 years. Long-term insurance products have been usually developed for accidental and sickness insurance, general property insurance, and even individual annuity. Due to large premium income in nature long-term insurance has grown up rapidly since its advent in 1969. That is the reason why a portion of direct premium from automobile insurance is quite less than around 50% unlike other countries with the fully developed property-liability insurance industry.2Although some property and liability insurance companies were licensed to sell automobile insurance after the Korean War (1950-1953), there was no actual business due to a lack of experience and uncertainty about its profitability. In 1957 the growing social concern about protecting persons injured by automobile accidents led to establish Korea Automobile Insurance Company operated by the National Automobile Transportation Association. After 4 year operation the company went bankruptcy due to mismanagement. Right after that, in 1962, a new Korea Automobile Insurance Company was established in the form of an insurance pool by 10 property and liability insurance companies. The company was converted to a stock company in 1968. Since 1962, the Korean automobile insurance industry has been monopolized by one company under a strict government control until the industry was opened to 13 property and liability insurance companies including 2 foreign companies in 1983.3Compulsory automobile liability insurance for bodily injury began in 1963 and also liability for property damage was mandated in 2004.4The Korean property-liability insurance companies do not disclose investment profits attributable to the fund from the automobile insurance sector since they do not have separate investment accounts according to the business lines.structure-conduct-performance (S-C-P) framework of industrial organization.5We also analyze the regulatory environment in which this industry operates and the possible effects of regulation and deregulation on industry performance as well as on industry structure and conduct.The study begins with an analysis of the structure of the automobile insurance industry with a brief history. This chapter deals with market concentration, entry barriers, and economies of scale as well as production. The third chapter examines the pricing behavior of the industry under the tariff system imposed by the government and the price liberalization starting in 1994. The effects of antitrust law against a cartel-like pricing behavior are presented. Chapter 4 examines the performance of the automobile insurance industry in the context of profitability of business and affordability and availability of insurance coverage.In the final chapter, some policy implications are proposed based on the analyses and concluding remarks follow.2. The structure of the automobile insurance industryBrief historyIn Korea a true automobile insurance business has begun with the establishment of Korea Automobile Insurance Company (KAIC) in 1962, which was funded by 10 incumbent property and liability insurance companies. Before 1962 Korean property and liability insurance companies’ operation had been confined mainly to fire and marine insurance, even though they had licenses to sell automobile insurance. They thought automobile insurance was very risky and unprofitable business since the market was very small with about 30,000 cars in the country and there was no accumulated data for rate-making.However, growing public concerns about automobile accident victims forced property and liability insurance companies to make an insurance pool to provide automobile insurance coverage on a voluntary basis. The outcome was an insurance pool, so called KAIC, which was converted to a stock company in 1968. In 1963 following year of the establishment, bodily injury liability with a policy limit became compulsory by the law. Since 1963, with rising automobile usage, the automobile insurance has become increasingly important in Korean property and liability insurance industry. Till 1997, when the long-term insurance overtook, the automobile insurance had been the largest part of the Korean property and liability insurance industry. <Figure 1> shows the premium distribution by lines of property and liability insurance5The content of this approach is that exogenous basic conditions determine market structure and that there is unidirectional flow of causality from market structure, through conduct, to performance. (Reid, 1987)from 1963 to 2005.Since 1962, the automobile insurance industry had been monopolized by one company under a strong government control until the industry was opened to 13 property and liability insurance companies including 2 foreign companies in 1983. Even after being seemingly the open market, the automobile insurance industry had been heavily regulated. All companies were required to use government-authorized premium rates, providing the same products at the same price.6There had been no price competition in the Korean automobile insurance industry. New entries to the market were virtually prohibited by the vague provision, so called ‘Economic Need Test’,7by which the government has the sole power to give a license to sell the automobile insurance.However, the regulatory environment was drastically changing with the 1996 affiliation with OECD (Organization for Economic Cooperation and Development) and the 1997 financial crisis.8By OECD, as a quasi-regulator, and IMF, as a creditor, the Korean government was strongly advised or/and required to remove government controls over the financial activities. Deregulation by external forces was directed to an open competition. One of two major changes in regulation was to remove an ‘Economic Need Test’from a license rule. Now anybody can do an insurance business if clearly specified entry conditions are met. Secondly, price competition has started since August, 2000 when an expense loading of gross premium was liberalized. One year later the expected claims cost, pure premium, can be determined by6The rating bureau, Korea Insurance Development Institute, had made gross premium rates based upon whole industry data until 2001, when the liberalization of premium loadings was getting started by individual companies.7‘Economic Need Test’ means that the government arbitrarily judges whether the country needs another insurance company when a company applies for a insurance license.8In 1997 to overcome a possible moratorium, the Korean government borrowed emergency funds from IMF, IBRD, and ADB.an individual company based on its own loss experiences.<Table 1: Recent Status of the Korean Automobile Insurance Market>Number of Firms, Entry and Market concentrationIn 1983 when the automobile insurance market was shifted to a competitive market from the monopoly, 13 property and liability insurance companies including 2 foreign companies took part in the market. All domestic companies were stock companies. There is no mutual company in the Korean insurance market. Until 1999 when one foreign company withdrew an automobile insurance line, there had been no change in the number of firms in the automobile insurance industry. In year 2000 one domestic company went into bankruptcy.9Only 11 companies started year 2001.In 2001 the first automobile mono-line insurance company entered the market after the entry regulation was changed. Two more mono-line companies joined the automobile insurance industry in 2003. Mono-line companies attacked the market with lower prices by using tele-marketing and internet marketing channels. With the advent of mono-line companies, real price competition started in the Korean automobile insurance market. As of March, 2006, 14 out of 28 property and liability insurance companies sell automobile insurance in Korea.<Table 2: Market Concentration in Automobile Insurance Industry>9This company was actually a foreign company since the company was purchased by a foreign capital a year ago.* Korea Fair Trade Commission considers a market concentrated if CR1≥0.5 and CR3≥0.75. ** The Horizontal Merger Guidelines issued by the US Department of Justice and the Federal Trade Commission classify markets as under: 0<HHI<1000, not concentrated, 1000<HHI<1800, moderately concentrated, and 1800<HHI, concentrated.Scale economiesThere is a big range in the size (in terms of premiums written as well as assets) of insurance companies selling automobile insurance in Korea. There are 4 companies with total annual premiums of over 1 trillion KRW and 10 companies with less than 1 trillion KRW. The so-called “Big 4” companies account for about 70% of the market. Usually it is of interest to ask whether or not the larger companies have a cost advantage over the smaller companies. Substantial cost advantages could indicate barriers to entry and the possibility that large companies could set prices substantially above marginal cost without provoking competitive entry. However, it is hard to expect that kind of pricing behavior since there was no price competition in the market before year 2000 when the tariff system was partially lifted.If there are economies of scale present, we would expect the expense ratio to decline with firm size. The economies of scale analysis performed here relates expense ratios to directpremiums written of only 10 out of 14 companies.10(Year 1999) ER = 38.72 -0.0000035DPW(29.45) (-1.811)R2 = 0.29(Year 2000) ER = 40.99 -0.0000059DPW(13.69) (-1.601)R2 = 0.24(Year 2001) ER = 33.66 -0.0000012DPW(23.99) (-0.827)R2 = 0.08(Year 2002) ER = 34.14 -0.0000017DPW(19.88) (-0.976)R2 = 0.11(Year 2003) ER = 34.82 -0.0000026DPW(36.18) (-2.656)R2 = 0.47(Year 2004) ER = 33.48 -0.0000011DPW(20.91) (-0.749)R2 = 0.07(Year 2005) ER = 38.34 -0.0000043DPW(12.77) (-1.498)R2 = 0.22,where ER = Expense Ratio and DPW = Direct Premium Written.The results of simple regression analysis provide only weak evidence of scale economies. Although the coefficient of the premium volume variable is negative in all cases, it is significant at the 5 percent level only in year 2003. Adding one more variable, a ratio of net premium to10Since one in bankruptcy and three newly entered companies have shown abnormal expense ratios, these companies are excluded in the analysis.direct premium to reflect reinsurance activity does not yield any better results. Distribution Channels<Table 3: Premium Distribution by Channels in Automobile Insurance>(KRW in billions)<Table 4: Expense Ratios of On-line Company vs. Traditional Company<Table 5: Premium Share of On-line Products>3. The conduct in the industryHow price is setThe way in which the volume, quality, and range of products are determined4. The Performance of the IndustryProfitabilitySince 1983 when the automobile insurance business was opened to the incumbent property and liability insurers, the insurers have complained that they are consistently losing large sums of money in operating the automobile insurance line. If they successfully convinced regulators, they were allowed to increase premium rates and improved loss ratios and underwriting profits. However, discussions of premium rates have often been based on misinformation about profitability in the industry.A traditional profit measure used in the property and liability insurance industry is the combined ratio. This ratio is very handy and provides some useful information about the insurance industry. However, it has often led to incorrect conclusions about profitability. The combined ratio, which is the sum of the loss ratio and the underwriting expense ratio, is used as an indicator of profitability. The loss ratio is an estimate of expected payments for reported and unreported claims, expressed as a ratio to earned premiums.11The underwriting expense ratio considers the expenses associated with writing insurance policies expressed as a ratio to earned premiums. A combined ratio over 100% indicates an underwriting loss. However, an insurance company can have a combined ratio over 100% and still be profitable, due to the fact that the combined ratio does not take into account earnings from investment income, which can offset underwriting losses.<Figure 2> shows the combined ratios of the automobile insurance industry from year 1983 to year 2005.11It is conventional that expected claims payments include loss adjustment expenses which are incurred to investigate and settle claims. In Korea, however, these expenses, about 2% of earned premiums, are considered a part of underwriting expenses. This practice allows the insurers to underestimate loss reserves.As a way to correct the combined ratio for investment income the overall operating ratio was introduced. The operating ratio is the combined ratio minus the ratio of investment income to premiums earned. Investment income is usually allocated by line on the basis of reserves (Cummins and Weiss, 1991) because data are not directly available on the investment income attributable to a particular line. To allocate aggregate investment income to the automobile insurance line, we assume that the share of total investment income is proportional to the share of total invested assets on the basis of the sum of unearned premium reserve, loss reserve and contingency reserve for the automobile insurance line. <Figure 3> shows the operating ratios from year 1983 to year 2005.The operating ratio is obviously a better measure of profitability as long as the insurers earn investment income from their invested assets funded by reserves to offset underwriting losses.<Table 5> shows the estimated profitability of automobile insurance from year 1998 to year 2005. The reason we choose year 1998 is that market valuation in assets and loan quality classifications have been used in the Korean insurance industry since 1998. However, the fair valuation method is not used in reserve valuations. If the reserves are not discounted, the claim payments that may not be made for several years are recognized as costs in the current year, thereby understating annual income.<Table 6: Estimated Profitability of Automobile Insurance from 1998 to 2005>(KRW in billions)Note: Underwriting gains/losses and operating gains/losses may not add or subtract due to rounding.<Table 7: Estimated Profitability of Property and Liability Insurance (except Automobile and Long-term Insurance) from 1998 to 2005>(KRW in billions)<Table 8: Estimated Profitability of Property and Liability Insurance from 1998 to 2005>(KRW in billions)* A rate of return on invested assets was only 3.67% compared to 8.12% of year 1999 due to stock market depression.** Rate of returns on invested assets: 6.05%(1998), 6.62%(2001), 4.33%(2002), 5.03%(2003), 5.48%(2004), 5.11%(2005)Affordability and Availability5. Policy Implications and Concluding Remarks<References>Cummins, J. D. and M. A. Weiss, 1991, “The Structure, Conduct, and Regulation of the Property-Liability Insurance I ndustry,” The Financial Condition and Regulation of Insurance Companies, edited by: Kopcke, R. W. and R. E. Randall, Boston, Federal Reserve Bank of Boston, pp: 117-154.Joskow, Paul L., 1973, “Cartels, Competition and Regulation in the Property-Liability Insurance Industry,” The Bell Journal of Economics and Management Science, Vol. 4, No. 2, pp. 375-427.Reid, Gavin C,, 1987, Theories of Industrial Organization, Oxford, UK, Basil Blackwell Ltd. Scherer, F. M. and D. Ross, 1990, Industrial Market Structure and Economic Performance, 3rd edition, Boston, MA, Houghton Mifflin.Smallwood, Dennis E., 1975, “Competition, Regulation, and Product Quality in the Automobile Insurance Industry,” in Promoting Competition in Regulated Markets, edited by A. Phillips, Washington, D.C., The Brookings Institution.Swiss Re, 2006, “World Insurance in 2005,” Sigma, No. 5., p. 35.Viscusi, W. K., John M. Vernon, and Joseph E. Harrington, Jr., 1992, Economics of Regulation and Antitrust, Lexington, MA, D.C. Heath and Company.05/31/07竞争与监管在韩国汽车保险业Wondon李*苏我Ewedemi ***副教授保险,大邱大学,韩国教授wlee@daegu.ac.kr**的金融学教授,克拉里昂宾夕法尼亚大学,美国ewedemi@1。
毕业设计(论文)外文参考资料及译文译文题目:Fuel supply system for an Internal Combustion Engine内燃机的燃烧供应系统学生姓名:学号:专业:所在学院:指导教师:职称:2014年 02 月 24 日Fuel Supply System For An Internal Combustion EngineAbstractA pulsation damper is provided between and in series with a low pressure fuel system pipe and a high pressure pump of a fuel supply system. During startup of an engine,low pressure fuel supplied via the low pressure fuel system pipe is injected from an intake passage fuel injector. When the fuel pressure is equal to or less than a fuel pressure at which good startability can be maintained,the pulsation damper closes off communication between the high pressure fuel system pipe and the low pressure fuel system pipe using the spring force of a spring.Key words: Fuel supply system; An internal combustion engine ;A pulsation damper;A low pressure fuel system pipe and a high pressure pump;A fuel supply system for an internal combustion engine,comprising: a low pressure pump that is capable to pressurize fuel; a low pressure fuel supply passage that is capable to supply fuel that was pressurized by the low pressure pump to a low pressure fuel injection mechanism which injects fuel into an intake passage; a branch passage that branches off from the low pressure fuel supply passage and through which the fuel that was pressurized by the low pressure pump flows; a high pressure pump which is capable to pressurize the fuel supplied via the branch passage,the high pressure pump being driven by the internal combustion engine; a high pressure fuel supply passage that is capable to supply fuel that was pressurized by the high pressure to a high pressure fuel injection mechanism which injects fuel into a cylinder; and a pulsation reducing mechanism provided on an intake side of the high pressure pump,wherein,when the internal combustion engine is started by only injecting fuel from the low pressure supply passage into the intake passage,the pulsation reducing mechanism closes off communication between the low pressure fuel supply passage and the high pressure fuel supply passage until a pressure of fuel in the low pressure fuel supply passage reaches a predetermined pressure value required for starting the internal combustion engine.Background of the invention :1. Field of the InventionThe invention relates to a fuel supply system for an internal combustion engine provided with a fuel injection mechanism that injects fuel at high pressure into a cylinder (i.e.; a fuel injector for in-cylinder injection,hereinafter referred to as “in-cylinder f uel injector”) and a fuel injection mechanism that injects fuel into anintake passage or an intake port (i.e.,a fuel injector for intake passage injection,hereinafter referred to as “intake passage fuel injector”). More particularly,the invention relates to a fuel supply system that can improve startability of an internal combustion engine.2. Description of the Related ArtA gasoline engine is known which is provided with a fast fuel injection valve for injecting fuel into a combustion chamber of the engine (i.e.,an in-cylinder fuel injector) and a second fuel injection valve for injecting fuel into an intake passage (i.e.,an intake passage fuel injector),and divides the injected fuel between the in-cylinder fuel injector and the intake passage fuel injector according to the engine speed and engine load. Also,a direct injection gasoline engine is also known which is provided with only a fuel injection valve for injecting fuel into the combustion chamber of the engine (i.e.,an in-cylinder fuel injector). In a high pressure fuel system that includes an in-cylinder fuel injector,fuel of which the pressure has been increased by a high pressure fuel pump is supplied to the in-cylinder fuel injector via a delivery pipe. The in-cylinder fuel injector then injects the high pressure fuel into the combustion chamber of each cylinder of the internal combustion engine.In addition,a diesel engine is also known which has a common rail type fuel injection system. In this common rail type fuel injection system,fuel which has been increased in pressure by a high pressure fuel pump is stored in a common rail. The high pressure fuel is then injected into the combustion chamber of each cylinder of the diesel engine from the common rail by opening and closing an electromagnetic valve.In order to increase the pressure of (i.e.,pressurize) the fuel in this kind of internal combustion engine,a high pressure fuel pump is provided which is driven by a cam provided on a driveshaft that is connected to a crankshaft of the internal combustion engine.Japanese Patent Application Publication No. JP-A-2005-139923 describes a high pressure fuel supply system for an internal combustion engine that can reduce vibrational noise when only a small amount of fuel is required by the internal combustion engine,such as during idling,while being able to deliver the necessary amount of fuel over the entire operating range of the internal combustion engine. This high pressure fuel supply system for an internal combustion engine has a two single plunger type high pressure fuel pumps each of which have a spill valve that spills fuel drawn into a pressurizing chamber that is divided by a cylinder and a plunger thatmoves back and forth in the cylinder,from that pressurizing chamber. When fuel is pressurized and delivered from the pressurizing chamber to the high pressure fuel system,the amount of fuel delivered is adjusted by controlling the spill valve open and closed. One of these high pressure fuel pumps is a first high pressure fuel pump in which the lift amount of the plunger is small and the other high pressure fuel pump is a second high pressure fuel pump in which the lift amount of the plunger is large. In addition to these two high pressure fuel pumps,the high pressure fuel supply system for an internal combustion engine also includes control means. The control means controls the spill valve of each high pressure fuel pump according to the amount of fuel required by the internal combustion engine,such that fuel is pressurized and delivered using only the first high pressure fuel pump when the amount of required fuel is small,and fuel is pressurized and delivered using at least the second high pressure fuel pump when the amount of required fuel is large.According to this high pressure fuel supply system for an internal combustion engine,of the two high pressure fuel pumps,the first high pressure fuel pump has a plunger with a small lift amount so the rate of pressure increase is small and a large amount of water hammer is also self-suppressed. That is,with the high pressure fuel supply system,the vibrational noise produced when the required fuel quantity is small can be preferably reduced by controlling the spill valve of each of the high pressure fuel pumps so that only the first high pressure fuel pump is used when the amount of fuel required for the internal combustion engine is small such as during idling. On the other hand,the second high pressure fuel pump has a plunger with a large lift amount so pressurizing and delivering fuel using at least this second high pressure fuel pump also makes it possible to deliver the required fuel quantity when the amount of fuel required by the internal combustion engine increases to the point where it can no longer be delivered by the first high pressure fuel pump alone. That is,providing two high pressure fuel pumps having plungers with different lift amounts in this way enables the required amount of fuel to be delivered throughout the entire operating range of the internal combustion engine,while reducing vibrational noise when the amount of required fuel is small.In Japanese Patent Application Publication No. JP-A-2005-139923,the high pressure fuel supply system for a V-type 8 cylinder internal combustion engine having an in-cylinder fuel injector in each cylinder is provided with a high pressure fuel pump for each bank. Tip ends that branch off from a low pressure fuel passage whichis connected to the fuel tank are connected to galleries of these high pressure fuel pumps. For each bank,a pulsation damper is provided midway between the branch portion of the low pressure fuel passage and the portion that connects with the gallery. This pulsation damper suppresses the pulsation in the fuel pressure in the low pressure fuel passage when the high pressure fuel pump is operating. At engine startup in this kind of a direct injection engine having only an in-cylinder fuel injector,fuel is unable to be delivered by the high pressure fuel pump until the engine turns over. Therefore,low pressure fuel is delivered by a feed pump to the fuel injection for in-cylinder injection. Therefore,the pulsation damper is designed to provide communication between the high pressure pipe system and the low pressure pipe system. For example,FIG. 6 is a sectional view of such a pulsation damper 215 ,FIG.7 is a sectional view taken along line VII-VII of FIG. 6 ,and FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7. As shown in FIGS. 6 to 8,grooves 223 A,223 B,223 C,and 223 D are provided in an end face (i.e.,the upper surface in FIG. 8) that abuts against a contacting member 226 A of the pulsation damper 215 . Therefore,when the feed pressure is low,the spring 226 D presses the contacting member 226 A against the upper surface of the member that forms the inlet 222 and the outlet 224 . In this way,the structure is such that even if pressure is applied by the spring 226 D,the grooves 223 A,223 B,223 C,and 223 D enable fuel delivered from the inlet 222 (i.e.,the feed pump side) to flow into the outlet 224 (i.e.,the high pressure fuel pump side) as shown by the dotted line in FIG. 8. On the other hand,as described above,an engine is known which includes,for each cylinder,an in-cylinder fuel injector that injects fuel into a combustion chamber of the engine and an intake passage fuel injector that injects fuel into an intake passage. In this engine,fuel is injected divided between the in-cylinder fuel injector and the intake passage fuel injector according to the engine speed and the load on the internal combustion engine. This engine is also provided with the pulsation damper shown in FIGS. 6 to 8.However,in this kind of engine,the following problems occur when starting the engine by injecting fuel with an intake passage fuel injector. When fuel is delivered by a feed pump at engine startup,the volume of pipe that needs to be charged with fuel becomes significantly larger. That is,when the engine is started with fuel injected from the intake passage fuel injector,despite the fact that fuel can be delivered to the intake passage fuel injector with the feed pump by simply charging only the low pressure pipe with fuel,the pulsation damper is structured such that the high pressure pipe system and the low pressure pipe system are communicated or open to one another. Therefore,fuel is unable to be delivered to the intake passage fuel injector by the feed pump unless both the low pressure pipe and the high pressure pipe arecharged with fuel. As a result,it takes time for the feed pressure to rise,thereby adversely affecting startability (i.e.,increasing the start time).Summary of the inventionThis invention thus provides a fuel supply system for an internal combustion engine,which is capable of improving startability of an internal combustion engine that includes a fuel injection mechanism for injecting fuel at high pressure into a cylinder (i.e.,in-cylinder fuel injector) and a fuel injecting mechanism for injecting fuel into an intake passage or an intake port (i.e.,an intake passage fuel injector).A first aspect of the invention relates to a fuel supply system for an internal combustion engine which includes a low pressure fuel supply passage that supplies fuel that was pressurized by a low pressure pump to a low pressure fuel injection mechanism which injects fuel into an intake passage; a branch passage that branches off from the low pressure fuel supply passage and supplies fuel to a high pressure pump that is driven by the internal combustion engine; a high pressure fuel supply passage that supplies fuel that was pressurized by the high pressure pump to a high pressure fuel injection mechanism which injects fuel into a cylinder; and a pulsation reducing mechanism provided on the intake side of the high pressure pump. The pulsation reducing mechanism closes off communication between the low pressure fuel supply passage and the high pressure fuel supply passage when a pressure of fuel in the low pressure fuel supply passage is lower than a predetermined value.According to this first aspect,the high pressure pump which is driven by the internal combustion engine does not operate during startup of the internal combustion engine. In this case,the internal combustion engine is started by injecting fuel that has been pressurized by the low pressure pump from the low pressure fuel injection mechanism via the low pressure fuel supply passage. In this case,during startup of the internal combustion engine when the pressure of fuel in the low pressure fuel supply passage is low,the pulsation reducing mechanism closes off communication between the low pressure fuel supply passage and the high pressure fuel supply passage. Therefore,fuel can be delivered to the low pressure fuel injection mechanism simply by charging the low pressure fuel supply passage with fuel using the low pressure pump. Accordingly,there is no need to charge the high pressure fuel supply passage with fuel using the low pressure pump so the low pressure fuel supply passage and the branch passage that provides communication between the low pressure fuel supply passage and the high pressure pump can be charged with fuel quickly,and fuel can bequickly injected from the low pressure fuel injection mechanism. As a result,startability of an internal combustion engine provided with a fuel injection mechanism that injects fuel at high pressure into the cylinder and a fuel injection mechanism that injects fuel into the intake passage or intake port can be improved.内燃机的燃油供应系统摘要在低压燃油供应系统管道和燃油供应系统的高压泵之间有一系列的有节奏的脉动衰减节气阀。
Sketching, concept development andautomotive designS ketching and its key role in concept design are identified, and the particular circumstances of automotive design described. A brief summary of work in the general field of concept sketching and visual thinking is presented. The particular characteristics of automotive design sketches; lines, crown lines, area lines, shading and colouring are described, and a delayering analysis undertaken. This demonstrates the primacy of form lines in the automotive design sketch. Observations, by video, of post-graduate students and six professional designers while sketching confirm the importance of the form lines in the design process, the interactive and iterative of concept development and the central role of the activity of sketching in this process. It is proposed that the design of CAD systems to support concept development must take account of importance of sketching activity.Keywords: conceptual design, drawing, visual thinking, automotive design, computer aided designMuch of the design theory and research work on sketching in design has been based on the domains of architectural design and engineering product design. None of it has drawn directly from the activities of automotive designers with the exception of Tovey. This is a specialised activity because of the particularities of the product form and, because of the high level of demarcation in the design and development process in the industry. Thus …computer aided has become a current phrase in the industry, by contrast with …computer aided design‟ in other fields. Work on computer aided styling has tended to concentrate on providing three dimensional alternatives to sketching, such as …virtual clay modelling‟ or simply conventional CAD surface modelling. There are many areas of apparent similarity between the activities of automotive designers and those of designers in other fields. A key question is the extent to which the work of design researchers in the other areas will translate to this specialist discipline, and the degree to which their apparently generic conclusions apply.Our investigations have been into the use of concept sketches by designers in the automotive industry. We have undertaken a number of formal exercises to observe designers and their methods in an effort to understand their techniques, and the content of their sketches. At the concept stage they use quick informal methods to provide an initial representation of the design. This representation of their ideas depends upon rapid direct techniques grounded in conventional methods based on pen and paper. It would seem that despite the availability of computer aided techniques to design- ers, none has been accepted by them as having equivalent utility.Our investigations have been into the use of concept sketches by designers in the automotive industry. We have undertaken a number of formal exercises to observe designers and theirmethods in an effort to understand their techniques, and the content of their sketches. At the concept stage they use quick informal methods to provide an initial representation of the design. This representation of their ideas depends upon rapid direct techniques grounded in conventional methods based on pen and paper. It would seem that despite the availability of computer aided techniques to designers, none has been accepted by them as having equivalent utility.These observations indicate that production of design ideas appears to depend upon the interaction with the concept sketches (as will be seen later, this confirms the observations of several previous researchers). The sketches are produced through the initial representation of form lines, and followed by shading to modify the shapes. The intention of this piece of research was to investigate whether or not these lines could form the basis for a CAD tool to produce 3D geometry from the sketches, and to see if the shading had the potential to provide secondary information to facilitate surface modification of this geometry. Moreover, the focus is very clearly on the very early, concept development stage of products in the automotive industry, the intention being that the easy availability of three dimensional geometry very early in this process can aid the development of concepts and speed up their communication to and evaluation by other parties in the development chain. For this reason, the types of sketches considered are those that occur in the very first stages of the automotive development process.1 Concept sketchesDesign sketches are different from …drawing from the object‟. They are not drawings of something that already exists, in front of the artist, as is the case with figure drawing, still life drawing and similar. Instead the designer is involved in a process of attempting to give external definition to an imagined, or only half imagined, suggestion for a design form.Prior work towards the understanding of the role of drawing in design was extensively summarised by Purcell and Gero4. This provides a comprehensive review of work relating to many types of drawing activity in the design process, including figures, diagrams and more general imagery. It is particularly sketches that we are concerned with hereThe sketches and other forms of drawing are languages for handling design ideas. The actual process of creating design ideas is usually envisaged as going on in the mind‟s eye and the drawings as attempts to reproduce the designer‟s mental images. The method is one of hand-eye co-ordination to produce the physical representation as a sketch on paper. Exercising this skill can be mentally relaxing, which in turn can reduce the inhibitions to the flow of thought. Whilst the designer is drawing there is a mental sifting and sorting of information, which can lead to design ideas. As soon as the image has been manifested in some concrete form such as a drawing or model (physical or computer) it becomes part of the information being handled to produce the next idea. The process is one of interactive generation.Different types of drawings are associated with different stages of the design process with one type, the relatively unstructured and ambiguous sketch occurring early in the process. Designers place great emphasis on the sketch often because it is thought to be associated with innovation and creativity. The conceptual stages of design are characterised by vague knowledge and shifting goals.One view of the purpose of concept sketches in the engineering domain is that they are intended to provide quicker communication and retrieval at the early stages of design, by providing combined visual and factual descriptions for improved evaluation and concept selection. A wider view is reported of the function of such drawings and related diagrams in the field of architectural design. The roles that designers ascribe to such representations in design include:●Generating concepts●Externalising and visualising problems●Facilitating problem solving and creative effort●Facilitating perception and translation of ideas●Representing real world artefacts that can be manipulated and reasoned with●Revising and refining ideas.In the engineering context three kinds of sketch have been identified.(1) The thinking sketch: used to focus and guide non-verbal thinking(2) The prescriptive sketch: used to direct a draftsman in making a finished drawing(3) The talking sketch: produced during exchanges between technical people in order to clarify complex and possibly confusing parts of the drawing.In the same context five levels of complexity have been identified for engineering concept sketches.Complexity level 1: Monochrome line drawing, no shading or colour, uniform line thickness Complexity level 2: Monochrome line drawing, no shading or colour.Line thicknesses vary to give emphasis. May include brief annotation. Complexity level 3: Monochrome with rough shading to suggest form.May be annotated.Complexity level 4: Line and shading, may include colour and graduation.Complexity level 5: Colour illustration to show what the productlooks like. Colour, shading, shadows, annotations, dimensions.This is similar to other codifications of levels of detail in representation for 2D models: Undetailed Diagrammatic drawings Abstract Schematic Representational Ideas sketching drawingsConcept drawingsMeasured drawings PackageGeneral ArrangementAxonometricDetailed Parts drawingsWe have identified a concept sketch as “a collection of visual cues sufficient to suggest the design to an informed observer”.The process of moving from an initially vague concept to a detailed design proposal can be likened to moving from an out of focus image to one that is fully detailed. The concept sketch as an initial representation of the out of focus design idea is clearly essential. In this definition, along with the others quoted above, the emphasis is placed on the sketch as perceived by others, not just the designer. Its private role, as a thinking aid to the designer is also essential, and other researchers have seen this as key to a successful visual thinking activity. Some of this work is discussed below.Figure 1 Example of line usage in a sketch.2 Visual thinkingDesign thinking, which is directed to specifying the visual form of a designed object, will of necessity involve visual representation. As McKim has shown visual thinking is greatly facilitated by representational procedures such as drawing in a three-way interaction of seeing, imaging and drawing. For architects this has been described so as to support abstraction and problem solving in a drawing based process.Similarly the analysis undertaken by Suwa, Purcell and Gero is grounded in the architecturaldomain. Their findings may be expressed as the following insights:(1) Sketches serve as an external memory in which to leave ideas for later inspection.(2) Sketches serve as a provider of visual cues for the association of functional issues.(3) Most importantly, sketches serve as a physical setting in which functional thoughts are constructed on the fly in a situated way.Also from the field of architecture, Schon and Wiggins have investigated kinds of seeing and their relationship with the design activity. They regard designing as a conversation with materials conducted in the medium of drawing, and crucially dependent on seeing. It is characterised as a reflective conversation with materials whose basic structure—seeing—moving—seeing—is an interaction of designing and discovery. Designers draw on paper, observing the evolving product of their work, employing different kinds of seeing (visual apprehensions, literal seeing), and as this is done discoveries are made. Features and relations are identified which cumulatively generate a fuller understanding, or …feel for‟the configuration with which she/he is working. They conclude that this involves attending to processes that computers are presently unable to reproduce.The work of Goldschmidt in this area, also based on architecture, is telling, and contains powerful insights. She deduces that designers invariably use imagery to generate new form combinations that they represent through sketching. Crucially, she adds that they also work in the opposite way; they sketch to generate images of forms in their minds. She asserts that interactive imagery through sketching is a rational mode of reasoning characterised by systematic exchanges between conceptual and figural arguments.Figure 3 Sketches producedIt is clear that the need for visualisation is recognised by almost all designers in diverse fields,from the arts to engineering. However, it is important to distinguish between that visual representation which is for the purposes of communication (with clients, colleagues or other interested parties) and that which is used for evaluation; that is to assess the quality of the design. Neither of these is what is meant by visual thinking. Rather it is the generation of new ideas, the reasoning that gives rise to them and facilitates the creation of form in designs (as opposed to their presentation).Sketches play an important role in the creative, explorative, open-ended phase of problem solving, facilitated by lateral transformations. As Garner notes: Pictorial representations, constructed during designing and taking the form of sketches, are important to designing because they impose both order and tangibility on the one hand, while on the other hand their ambiguity stimulates re-interpretation. The very lack of clarity may be important. It is apparent that there is a wealth of existing research concerning the concept sketch; the purpose it has, the media through which it is achieved and its potential for being supported by computers. There is, however, very little research directly pertaining to the automotive concept sketch and whether it is possible to support the production and use of them using computers. In an industry heavily committed to CAD and where there is an increasing pressure to reduce lead times it is an area full of research opportunity.。
Motors and gearboxesAs the world energy crisis, and the war and the energy consumption of oil -- and are full of energy, in one day, someday it will disappear without a trace. Oil is not in resources. So in oil consumption must be clean before finding a replacement. With the development of science and technology the progress of the society, people invented the electric car. Electric cars will become the most ideal of transportation.In the development of world each aspect is fruitful, especially with the automobile electronic technology and computer and rapid development of the information age. The electronic control technology in the car on a wide range of applications, the application of the electronic device, cars, and electronic technology not only to improve and enhance the quality and the traditional automobile electrical performance, but also improve the automobile fuel economy, performance, reliability and emissions purification. Widely used in automobile electronic products not only reduces the cost and reduce the complexity of the maintenance. From the fuel injection engine ignition devices, air control and emission control and fault diagnosis to the body auxiliary devices are generally used in electronic control technology, auto development mainly electromechanical integration. Widely used in automotive electronic control ignition system mainly electronic control fuel injection system, electronic control ignition system, electronic control automatic transmission, electronic control (ABS/ASR) control system, electronic control suspension system, electronic control power steering system, vehicle dynamic control system, the airbag systems, active belt system, electronic control system and the automatic air-conditioning and GPS navigation system etc. With the system response, the use function of quick car, high reliability, guarantees of engine power and reduce fuel consumptionand emission regulations meet standards.The car is essential to modern traffic tools. And electric cars bring us infinite joy will give us the physical and mental relaxation. Take for example, automatic transmission in road, can not on the clutch, can achieve automatic shift and engine flameout, not so effective improve the driving convenience lighten the fatigue strength. Automatic transmission consists mainly of hydraulic torque converter, gear transmission, pump, hydraulic control system, electronic control system and oil cooling system, etc. The electronic control of suspension is mainly used to cushion the impact of the body and the road to reduce vibration that car getting smooth-going and stability. When the vehicle in the car when the road uneven road can according to automatically adjust the height. When the car ratio of height, low set to gas or oil cylinder filling or oil. If is opposite, gas or diarrhea. To ensure and improve the level of driving cars driving stability. Variable force power steering system can significantly change the driver for the work efficiency and the state, so widely used in electric cars. VDC to vehicle performance has important function it can according to the need of active braking to change the wheels of the car, car motions of state and optimum control performance, and increased automobile adhesion, controlling and stability. Besides these, appear beyond 4WS 4WD electric cars can greatly improve the performance of the value and ascending simultaneously. ABS braking distance is reduced and can keep turning skills effectively improve the stability of the directions simultaneously reduce tyre wear. The airbag appear in large programs protected the driver and passenger's safety, and greatly reduce automobile in collision of drivers and passengers in the buffer, to protect the safety of life.Intelligent electronic technology in the bus to promote safe driving and that the other functions. The realization of automatic driving through various sensors. Except some smart cars equipped withmultiple outside sensors can fully perception of information and traffic facilities and to judge whether the vehicles and drivers in danger, has the independent pathfinding, navigation, avoid bump, no parking fees etc. Function. Effectively improve the safe transport of manipulation, reduce the pilot fatigue, improve passenger comfort. Of course battery electric vehicle is the key, the electric car battery mainly has: the use of lead-acid batteries, nickel cadmium battery, the battery, sodium sulfide sodium sulfide lithium battery, the battery, the battery, the flywheel zinc - air fuel cell and solar battery, the battery. In many kind of cells, the fuel cell is by far the most want to solve the problem of energy shortage car. Fuel cells have high pollution characteristics, different from other battery, the battery, need not only external constantly supply of fuel and electricity can continuously steadily. Fuel cell vehicles (FCEV) can be matched with the car engine performance and fuel economy and emission in the aspects of superior internal-combustion vehicles.Along with the computer and electronic product constantly upgrading electric car, open class in mature technology and perfected, that drive more safe, convenient and flexible, comfortable. Now, the electric car from ordinary consumers distance is still very far away, only a few people in bandwagon. Electric cars with traditional to compete in the market, the car will was electric cars and intelligent car replaced. This is the question that day after timing will come. ABS, GPS, and various new 4WD 4WS, electronic products and the modern era, excellent performance auto tacit understanding is tie-in, bring us unparalleled precision driving comfort and safety of driving.The role of transmissionThe output of the engine speed is very high, maximum power and maximum torque at a certain speed area. Engine in order to exert the best performance, it is necessary to have a variable-speed devices, to coordinate the engine speed and the actual wheel speed. Transmissionprocess in the car, in between the engine and the wheels have a different gear ratio, by shifting the engine can work at their best performance of state power. Transmissions are the development trend of more and more complex, increasingly high degree of automation, automatic transmission will be the mainstream of the future. Transmission typeAutomotive automatic transmission has three common forms: namely, Automatic Transmission (AT), mechanical stepless automatic transmission (CVT), electric-controlled mechanical automatic transmission (AMT). At present, the most widely used is the AT, AT almost become synonymous with automatic transmission.AT Torque by Torque, and planetary gear and hydraulic control system components, through the hydraulic transmission and gear portfolio approach to achieve variable-speed torque variation. One of Hydraulic Torque is the most important parts, which pump wheels, turbines and components, such as guide pulley of the transmission of both torque and the role of clutch.AT compared with, CVT save the complex and cumbersome combination of variable-speed gear transmission, but the two groups to carry out variable-speed drive pulley. By changing the driving wheel and driven wheel contact belt speed radius. Canceled because of gear, so the transmission ratio can change speed more smoothly, without shifting sense of the sudden jump.AMT and Automatic Transmission (AT) are the same class has automatic transmission. It is in general based on the manual transmission, through the installation of microcomputer-controlled electric device to replace the original finish by the manual operation of the clutch of separation, joint, and block transmission of the election, motion shift, automatic shift implementation.The general structure of automobile transmission1. Easy transmission of the basic structure: the shell, transmissionand manipulation of some parts.(1) Shell: Shell is the basic pieces of support for the installation of transmission and storage of all parts lubricants. Has installed its bearing on the precision boring. Transmission under varying load, so the stiffness of the shell should be enough, there is to strengthen the wall, the shape of the complex, as many castings (gray cast iron materials, commonly used HT200).In order to facilitate the installation, transmission and manipulation of some Split parts are frequently made, cover with the housing connected by bolts and reliable positioning. Shell has come on up, I put the oil, check oil foot mouth, should also be taken into heat dissipation.(2) Transmission parts: is the gear, shaft, bearings and other transmission parts. Geometry axis through strength, stiffness calculation. Mainly due to decide on the stiffness, while the carbon steel and alloy steel elastic modulus almost equal, so the general use of carbon steel (commonly used 45 steel). Only one gear with the shaft or axle load made serious only by steel. Shaft and gear for many spline connection (for neutral good, reliable transmission of power, a small compressive stress, etc.). Spline shaft bearing parts and let the surface hardening treatment by the Department. Shaft with rolling bearing supports many, easy lubrication, high efficiency, small radial clearance, axial positioning should be reliable. Many ways to use splash lubrication (υ> 25m / s, as long as the appropria te viscosity apparently succumbed to the wall).(3) to manipulate parts: the main components located inside the transmission cover.2. The composition of the structural characteristics of transmission: there is easy and efficient transmission, the advantagesof simple easy-to-use-Jun mine but a few files, i changed the scope of small (traction, speed small), file number should be taken only atcertain limited Cut used. If the increase in the scope of i, then increase the size so that transmission, axle span increase, both in order to increase the file-axis span of a few do not make too large, transmission can be formed. The composition of the so-called transmission, usually from both a combination of easy transmission, one of a few more files as the main transmission, less transmission known as the deputy. Transmission component of advantages:(1) can reduce the number of gears, and a few more files to reduce the number of gear the more obvious advantages. Easy compared with the transmission, it can shorten the length of shaft to reduce the transmission of the external size and weight, and can easily be more than one reverse. Into the file so the current number of files more than six hours, almost all transmission components.(2) transmiss ion: the rate of change of Ω than large: if the main transmission gear ratio change rate Ωzu = 3, Vice transmission Ωfu = 4 is Ω = 12; easy transmission arrangement Ω = 12, the structure is often difficult to reasonable.Composed of transmission of disadvantage:(1) file groups have correspondence between the transmission ratio, so that each file is not 2, (the speed and traction) are ideal.(2) manipulation of trouble shifting, and sometimes both want to manipulate some speed, if not for the flower arrangement will shift memory.In order to reduce the control action, it is best to shift the order. Calling attention to the grade for this presentation ten out files so that the first group of transmission ratio is greater than all of the first file group 11 to the majority of phase transformation from the stall speed of just fixing the main purpose of this is the only way most convenient. GM Hydra-MaticGeneral can be regarded as the founder of automotive automatic transmission has been. The world's first automatic transmission is usedin the United States in 1940 Oldsmobile automobile on a common, and it is a tandem structure of planetary gear transmission fluid control. Applies to the Cadillac STS-V's latest six-speed Hydra-Matic automatic transmission 6L80, may be regarded as the world's most advanced Automatic Transmission (AT) has been.Automatic Transmission For example, it has an internal gear is also divided, but the abolition of the clutch. The more gear, then shift, the better the ride comfort. At present, common automatic transmission are generally four-speed, that is, block has four forward. 6L80 has six forward gear, the number of teeth than the one block are separately 2.36,3 block 4.03,2 block 0.85,6 block 1.15,5 block 1.53,4 block 0.67. Obviously, it is more than 4-speed automatic transmission with a greater ratio and smaller ratio of the difference, it is more smooth when speed.Outside the block a few more besides, 6L80 also has a lot of unique special skills:Driver shift control system (DSC) - through its driver into a vehicle without the clutch from the automatic five-speed, high-performance手动挡. Drivers under the food stalls to the DSC on the location, the light touch can be specified at the scope of the neat, smooth implementation block addition and subtraction. The driver to switch control mode, the transmission control module monitors the vehicle speed, engine torque and gear used to decide whether to automatically add block to avoid damage to the powertrain. Each have a sliding gear on the clutch, can be carried out on all five gear engine braking.Performance computing systems down block (PAL) - in a row after a high-speed, stop升挡maintain engine braking. Transmission control module based on driving behavior to decide whether to activate the device. If the system found in the vehicle slowed down before turning, transmission may be even lower in order to avoid stall twoblock.Performance computing shift system (PAS) - turn off the accelerator in high-speed automatic adjustment of the level of acceleration gear, re-open at throttle-down power to elevate. Once the transmission control module to detect high levels of command, this function immediately.This transmission also reduced in the rugged mountain road "Shift Search," the stability of the shift functions, with the lower block BrakeAssist monitoring function, electronically controlled engine braking, as well as to adapt to these high-power, high torque engines are the new need a new dual-chip torque converter. In addition, SRX is also equipped with high-performance downhill Downgrade Detection Brake Assist.Chinese car market gearboxChina's auto market is in a transmission period of rapid development. 2007 Chinese sales of 8,791,500 motor vehicles, motor vehicle production in 2008 will exceed nine million sales, car sales in 2010 will reach 12.63 million. Size of the market in the automotive industry's rapid growth, China is faced with a major transmission industry opportunities. In 2006 the market scale of China's automobile transmission up to 300 billion yuan and more than 20% annual growth is expected in 2010 is expected to reach 60 billion yuan.汽车与变速箱随着世界能源危机的持续,以及战争和能源-----石油的消耗及汽车饱有量的增加,能源在一天一天下降,终有一天它会消失的无影无踪。
TransmissionBrakesBrake is a movement of vehicles or impede the movement of the trend components. According to brake torque generated in different ways, the brakes can be divided into: friction brake and retarder brakes, brake, broadly speaking, usually referred to the friction brake. At present all kinds of cars used by the brake drum brakes and can be divided into two major categories of disc brakes. Drum brake friction in the rotating components of the brake drum, and its work surface for the cylindrical surface of the rotating disc brake components for the brake disc, to end the work surface. In addition, under the rotating components of the installation of different positions, the brakes can be divided into the wheel brakes and brake two categories. Among them, the rotating wheels, brake components installed in thesolid-wheel or axle, brake torque that is a direct role in both sides of the wheels, respectively, for its general travel brake, and can also be used to brake the second and the car braking; rotating components of the brake-installed in the transmission of the transmission shaft, after its brake torque to be driven to the redistribution of the bridge on both sides of the wheel, generally used only for its cars in the system Retarded and dynamic braking.Drum brakes are within and outside the beam-type-two. The former brake drum to work within the cylindrical surface of the car on the wide application of the latter brake drum is the work of Outer cylindrical surface, only a handful of cars will be used in car brakes.Zhang-drum brakes, mainly by the brake drum (Xingzhuang Si pot, installed in the wheel, and synchronization with the rotating wheels), brake shoes, (arc-shaped parts, a group of two, shoes, with a lateral Nien Moment of friction brake lining film), fixed sales andbrake-cylinder, and so on. Brake, brake drum in the internal brake shoes, brake points from one end to bear the Prokinetic cylinder, around the other side of the fulcrum of its outward rotation, the pressure on the brake drum with a round face, then friction Torque.Disc brake mainly by the brake discand calipers. Among them, ventilated brake disc-andtwo-solid; mainly floating calipers clamp, fork-floating, such as several fixed-clamp. Braking system of new technologiesAs people of vehicle safety requirements and the continuous improvement of the rapid development of electronic technology, today's automobile braking system have taken place in the revolutionary progress. On the one hand, the brake system through a variety of sensors for real-time monitoring of the braking system braking to provide a more efficient and effective security assurances on the other hand, automobile braking systems and other systems constitute stretches of the regional network, in Implementation of intelligent brake control at the same time, but also further reduce the energy consumption of motor vehicles; addition, with new materials and new structure of the large number of applications, the reliability of its braking system has been further improved.制动器是产生阻碍车辆运动或运动趋势的力的部件。
摘要本文主要研究轻型汽车前独立悬架的设计分析方法以及轮胎磨损与悬架运动、前轮定位参数的关系。
首先对双横臂独立悬架的各主要组成部件如减振器的选型设计、横向稳定杆的设计校核、扭杆弹簧设计以及对双横臂式和麦弗逊式独立悬架的运动进行了分析,提出了相应的计算方法,编制了一套具有一定实用价值的前独立悬架设计分析软件。
并且采用前轮定位仪,进行了实验验证。
论文对双横臂独立悬架参数提出以减小轮胎磨损为优化目标,进行了优化设计。
提出了通过优选、调整悬架初始位置状态,以及优化确定转向横拉杆断开点位置的方法,来减小轮胎磨损。
同时采用正交实验的方法分析了双横臂独立悬架各结构参数和安装参数对悬架性能和轮胎磨损的影响,确定出最大的影响因素及次要因素。
然后从轮胎模型入手分析前轮定位参数同轮胎磨损的关系。
以轮胎磨损能量作为评价指标,选取刷子轮胎模型,对轮胎在稳态纵滑状态下、稳态纵滑侧偏状态下和边界条件下的轮胎磨损进行了分析研究,确定了量化模型。
并以轮胎侧偏角为中间变量,建立了前轮定位参数同轮胎磨损之间关系的数学模型,进行了计算机仿真计算。
从而可对悬架进行进一步的优化设计,以减小对轮胎磨损的影响,提高车辆的行驶性能和使用经济性。
关键词:汽车;独立悬架;轮胎磨损;定位参数悬架系统原理Kaoru Aoki, Shigetaka Kuroda, Shigemasa Kajiwara, Hiromitsu Sato and Yoshio YamamotoHonda R&D Co.,Ltd.悬架系统虽不是汽车运行不可或缺的部件,但有了它人们可以获得更佳的驾驶感受。
简单的说,它是车身与路面之见的桥梁。
悬架的行程涉及到悬浮于车轮之上的车架,传动系的相对位置。
就像横跨于旧金山海湾之上的金门大桥,它连接了海湾两侧。
去掉汽车上的悬架就像是你做一次冷水潜泳通过海湾一样,你可以平安的渡过整个秋天,但会疼痛会持续几周之久。
想想滑板吧!它直接接触路面你可以感受到每一块砖,裂隙及其撞击。
2010China International Automobile Manufacturing and Producing Facility ExpositionPreparation time: October 26-28, 2010Book booth Area: China International Exhibition Center (Old Hall)Theme: Gathering of Finest Facilities Origin of High-quality AutomobilesTotal Exhibition Area: 27,000m2Number of exhibitors: 600 exhibitors come from 30 countries and regions Number of audiences: 12,000 audiences from 60 countries and regionsExhibits Profile:Automotive Manufacturing: metal cutting, stamping casting and forging, welding and cutting,coating technologies and painting, assembly, monitoring and inspection, testing and experiments, automation and drives, logistics and supply chain, information technology, design and development, materials, heat treatment, new products.Parts Machining: Automotive parts and components processing of metal cutting, grinding, milling, drilling, machine tool equipment; stamping, forging, bending technology and equipment; automotive interior parts cutting, cutting, polyurethane foam technology and equipment; engine manufacturing plane equipment, measuring equipment; gear machining and bearing special equipment, laser cutting, marking technology and equipment, numerical control cutting tool, coating technology, metal processing oil.New energy, environmental protection, energy-saving technology equipment and products of automobiles;Schedule:Preparation time: October 24-25, 2010Opening ceremony: 10:00 AM October 26, 2010Opening time: October 26-28, 2010Move-out time: 16:00 PM October 28, 2010Cost of Exhibition:(Pairs of opening booths, plus 10%)Section A: Standard booth ¥16800/9 m2Section B:Standard booth ¥13800/ 9 m2Section C: Standard booth ¥9800/ 9 m2Indoor Ground(36m2 on hair):¥1280/ m2Same time activities: symposia, face-face trade fair,purchase introduction and products introduction.Sponsoring Units:China Council for the Promotion of Intermational Trade Authorization Unit:China International Economic and Technical Cooperation Consultants IncOrganization Unit:China International Economic and Technical Cooperation Consultants IncUndertaken Unit:China International Economic and Technical Cooperation Consultants IncDongdu International Exhibition (Beijing) Co., LtdSupport Unit:China Automotive Industry AssociationChina Society of Automotive EngineeringOfficial media:Automobile Manufacturing and Production Facility Exposition Exposition on-line:Exhibition contact:Room 1002,Floor 10,Nan Li Shi Lu 66, Xicheng District, Beijing, Postal Code100045 Telephone number:Tex number:Contact person:E-mail:Report after China International Automobile Manufacturing and Producing Facility ExpositionOverview of CIAMPFE:2009 China (Beijing) International Automobile Manufacturing and Producing Facility Exposition (CIAMPFE) has succeed in China(Beijing)International Exhibition Center from November the11th to13th. It received a positive response from the community and broad participation.China Automotive Industry Association and China Society of Automotive Engineering authoritative organizations expressed its support. The United States, Japan, Germany,Britain, South Korea, India, Belgium, Poland, Turkey and other countries embassy officials gave a high degree of attention and support, and they will continue to participate in next year's exposition.Scale of CIAMPFE:Influenced by the financial crisis, the first CIAMPFE covers a floor space of about 22000 square meters as planned, but the actual area is 14600 square meters . More than 268 exhibitors, including 39 enterprises are special equipment booth, which cover 6182 square meters, accounting for about 42.34% of the total area of the exhibition area.At the same time,three-days symposia, face-face trade fair,purchase introduction and products introduction meeting were held. It makes exhibitors and visitors got better communication and cooperation.Audiences of CIAMPFE:More than thirty companies were invited to visit: Germany's BMW, Beijing Benz - Daimler-Chrysler, Beijing Automotive Holdings, Beijing Hyundai, Beijing Foton, SAIC, Changchun FAW, Guangzhou Automobile Group, BYD Auto of Shenzhen, Yunnan Hongta, Chery of Anhui, Hebei Great Wall Motor, Tianjin Xiali, Zhejiang Geely Group, Hafei Motor, Zhengzhou Yutong, youth Automotive Group, Dongan Auto, Auman heavy-duty vehicles, Beijing Automotive Research Institute, the China Auto Parts Industry Company,No.1 Group of China Aviation Industry Corporation, China North Vehicle Research Institute, China Shipbuilding Industry, No.1 Group of China Tractor , South Korea Incheon, South Korea Ching Industrial Co., Ltd., Bosch, Denso Corporation, Delphi Corporation, Magna Group, Beijing Automotive Li Er, Dongfeng auto parts, Wuhu Lingyun Industrial, Central power, the United States and Germany auto parts and so on. In addition to the media and some exhibition counterparts, above 98% are professional visitors.Fen Xuehong, Purchasing Manager of BMW Automobile Co., LTD. said, "for the high-quality exhibitors, organizer's invitation is very professional.Such scale of automobile manufacturing industry chain is the first case in the international exhibition. Particularly it has brought new technologies and products for the automobile manufacturing technology and equipment, etc."Mao Dehe, Vice-president of Shenzhen BYD Auto Co., Ltd. Said, "all aspects of the exposition is good. After 3-day visit, I saw the advanced technology and equipment on international and domestic automobile manufacturing field , and the rapid development of domestic automobile manufacturing equipment and technology. On behalf of the industry's highest grade, there are international leading-edge technology and products on the exposition, it gives us China's own brand carmakera great harvest."Exhibitors' Experience:David Wang, the Sales Manager of IPG (Beijing) Fiber Laser Technology Co., Ltd. affirmed the professionalism of the exhibition, and said he will participate the next exposition, and had been booking an exhibition booth .Hao Gepp Ruite, director of Germany Wolf Group Asia District, accept CCTV network reporters said, "Although the exposition affected by the weather, exhibitors and spectators are not too much. The automobile industry for the ordinary people are not closely related, but the industry still come to visit. To enhance the Wolf Group's reputation in the industry, and we will continue to participate in next year's exposition. "Wu Wenzhi, executive director of South Korea's POSCO Specialty Steel Co., Ltd.received a number of media interview and said “CIAMPFE will expand Chinese market as anopportunity.”Li Lei, Sales Manager of Beijing High-tech Electrical and Mechanical Co., Ltd. accept CCTV interview, said: "The purpose of attending the exhibition is promoting products and expanding market share. CIAMPFE has clear conception and very professional. We believe that the organizer has applied good service. I hope the exposition will enlarge the scale and we can participate in next year's exhibition.China Daheng (Group) Co., Ltd.with a low-key appearance standard booths, but still attracted a lot of professional audience. The General Manager Jiang Zhengmin of Laser Engineering Branch contended frankly: Although the scale is not large, there is still a good harvest.Achievement of CIAMPFE:On-site turnover:¥61.78 millionAudiences number:7712Contract value:¥185,000,000Professional of the exhibitors:100%Professional of the audiences:98.68%Media index:0.42%2010年中国国际汽车制造及生产设备展览会准备时间:10月26-28,2010预订展位面积:中国国际展览中心(老馆)主题:最好的设施收集原产地高品质的汽车总展览面积:27,000平方米参展商数量:来自30个国家和地区600家参展商观众人数:12000来自60个国家和地区的观众展品范围:汽车制造:金属切削,冲压铸件和锻造,焊接和切割,涂装技术和涂装,总装,监督和检查,测试和实验,自动化和驱动器,物流及供应链,信息技术,设计和开发,材料,热处理,新产品。
On the vehicle sideslip angle estimation through neural networks: Numerical and experimental results.
S. Melzi,E. Sabbioni
Mechanical Systems and Signal Processing 25 (2011):14~28
电脑估计车辆侧滑角的数值和实验结果
S.梅尔兹,E.赛博毕宁
机械系统和信号处理2011年第25期:14~28
摘要
将稳定控制系统应用于差动制动内/外轮胎是现在对客车车辆的标准(电子稳定系统ESP、直接偏航力矩控制DYC)。
这些系统假设将两个偏航率(通常是衡量板)和侧滑角作为控制变量。
不幸的是后者的具体数值只有通过非常昂贵却不适合用于普通车辆的设备才可以实现直接被测量,因此只能估计其数值。
几个州的观察家最终将适应参数的参考车辆模型作为开发的目的。
然而侧滑角的估计还是一个悬而未决的问题。
为了避免有关参考模型参数识别/适应的问题,本文提出了分层神经网络方法估算侧滑角。
横向加速度、偏航角速率、速度和引导角,都可以作为普通传感器的输入值。
人脑中的神经网络的设计和定义的策略构成训练集通过数值模拟与七分布式光纤传感器的车辆模型都已经获得了。
在各种路面上神经网络性能和稳定已经通过处理实验数据获得和相应的车辆和提到几个处理演习(一步引导、电源、双车道变化等)得以证实。
结果通常显示估计和测量的侧滑角之间有良好的一致性。
1 介绍
稳定控制系统可以防止车辆的旋转和漂移。
实际上,在轮胎和道路之间的物理极限的附着力下驾驶汽车是一个极其困难的任务。
通常大部分司机不能处理这种情况和失去控制的车辆。
最近,为了提高车辆安全,稳定控制系统(ESP[1,2]; DYC[3,4])介绍了通过将差动制动/驱动扭矩应用到内/外轮胎来试图控制偏航力矩的方法。
横摆力矩控制系统(DYC)是基于偏航角速率反馈进行控制的。
在这种情况下,控制系统使车辆处于由司机转向输入和车辆速度控制的期望的偏航率[3,4]。
然而为了确保稳定,防止特别是在低摩擦路面上的车辆侧滑角变得太大是必要的[1,2]。
事实上由于非线性回旋力和轮胎滑移角之间的关系,转向角的变化几乎不改变偏航力矩。
因此两个偏航率和侧滑角的实现需要一个有效的稳定控制系统[1,2]。
不幸的是,能直接测量的侧滑角只能用特殊设备(光学传感器或GPS惯性传感器的组合),现在这种设备非常昂贵,不适合在普通汽车上实现。
因此, 必须在实时测量的基础上进行侧滑角估计,具体是测量横向/纵向加速度、角速度、引导角度和车轮角速度来估计车辆速度。
在主要是基于状态观测器/卡尔曼滤波器(5、6)的文学资料里, 提出了几个侧滑角估计策略。
因为国家观察员都基于一个参考车辆模型,他们只有准确已知模型参数的情况下,才可以提供一个令人满意的估计。
根据这种观点,轮胎特性尤其关键取决于附着条件、温度、磨损等特点。
轮胎转弯刚度的提出就是为了克服这些困难,适应观察员能够提供一个同步估计的侧滑角和附着条件[7,8]。
这种方法的弊端是一个更复杂的布局的估计量导致需要很高的计算工作量。
另一种方法可由代表神经网络由于其承受能力模型非线性系统,这样不需要一个参
考模型。
变量之间的关系表明,实际上车辆动力学的测量板测和侧滑角通常是纯粹的数值而它的结果则是从一个网络“学习”复制目标输出关联到一个特定的输入的训练过程。
在本文可以发现一些尝试应用神经网络技术对侧滑角估计。
在[9],侧滑角在即时k + 1,k, k -1,k - n的值是作为一个功能的横向加速度和角速度的估计。
从结果来看解决似乎很有前景,但车辆速度变化的影响(不包括在神经网络的输入变量)和对路面附着系数的问题仍未解决。
神经网络中表明不是基于一个非常规组传感器:输入到神经网络实际上是这些措施提供了四个双轴加速度计放置在对应的车身设计的每一个角落。
然而,即使在这种情况下,影响附着条件对神经网络性能仍无法解决。
本研究的目的是进一步调查这种应用神经网络的方法对侧滑角估计作为输入的可能性,通常只有测量获得了板测量(横向/纵向加速度、角速度,引导角和车辆速度)和考虑速度和附着状况的变化。
特别地, 因为这个架构显示有一个广泛的适用性动态表示问题,一个双层(或单隐层)神经网络设计才得以出现[11]。
在第一阶段的研究, 在一个分布式光纤传感器的车辆模型基础上进行了数值分析结果。
期间,一直在输入不同的的数值进入人工神经网络系统,直到得到满意的结果为止。
采用的训练集的特点是,在高/低粘附路面上演习不同谐波内容(步骤引导,横扫正弦驾驶),水平的横向加速度。
此外,选择包括输入之间的神经网络估计侧滑角已经决定。
随后,一旦确定了最佳输入和训练集, 在一个检测车辆的实际驾驶情况后处理获得的实验数据,实现人工神经网络性能和稳定。
特别是,大部分人的注意力都集中在神经网络的能力上,以提供在内外线性车辆响应范围内和在高或低摩擦路面上稳态或瞬态侧滑角的可靠的估计。
2 数值数据应用
在第一阶段的一个人工神经网络工作组进行训练和测试通过数值数据;这一阶段的主要目标是设计一个能够在不同的路面上提供准确和可靠的侧滑角估计的一个神经网络与一个合适的体系结构。
神经网络在动态仿真模块环境下实现一个简化的d段客车车辆模型生成信号的训练和测试;数值模型利用分布式光纤传感器的车辆模型来描述在水平面的位移的重心(c.o.g)偏航运动身体和四个轮子的旋转.基于括在车辆模型纵向和侧向加速度包的瞬时负载转移,以考虑每个轮胎在车削、加速和制动演习时候的垂直荷载的变化。
相反悬架阻尼和刚度总被忽视, 因为这个参数必须正确估计,所以除了之间的比率前/后辊刚度不同负载转移而转弯。
引导角,油门/刹车位置和齿轮被视为输入模型。
轮胎的交互作用模拟1996版的Pacejka 中频[14]中允许考虑滑移条件相结合。
摩擦系数是按比例复制的峰值摩擦系数从而改变的。
一旦确认通过与实验测量的比较,该模型用于生成一组训练演习,并提供一些数据来
检查网络系统的性能。
在这个过程中几个变量会应用到网络,特别是到向量的输入数据,直到得到与测量数据前的测试满意的结果。
2.1 网络的架构
一般来说一个神经网络[12,13]是MIMO非物质模型,其主要优势是在减少计算时间,其基本单位的乘坐被称为神经元,每一个神经元都能够执行简单的数学运算;神经元集成在一个可以实现一种并行计算结构里。
每个网络的特点是一定数量的参数所代表的收益和权重的神经元, 神经元是通过一个训练阶段决定的,该阶段是一组时间历史的输入信号是提供给网络和相应的目标值与输出网络本身,这个过程是反复地重复调整参数,直到输出匹配目标在所需的公差范围内。
除了数量的神经元之外,神经网络的架构定义的层数和神经元间的连接增加的复杂性往往导致高专业化的网络,该网络显示有限能力适应条件的不同的训练集(过度拟合)。
因此选择一个合适的体系结构是一个在准确性和灵活性之间妥协的结果,这最后的功能的特别利害关系的应用程序检查在这个工作因为只有有限数量的演习可以作为训练集,汽车车辆的工作条件可以作为变量对轮胎附着力也是如此。
提出的神经网络是一种前馈(信号从输入到输出的旅行没有内部循环),由10个隐藏的s形神经元和单个输出线性神经元构成。
附件外文原文。