Principle of electronic accelerator pedal for BMW car

BMW uses an electronic accelerator pedal.

The electronic accelerator transmits the signal of the depth and speed of the accelerator pedal through the position sensor, and this signal will be received and interpreted by the on-board microcomputer, and then a control command will be issued, requiring the accelerator to open the angle it should open quickly or gently according to the command. This process is accurate and fast. There will be no mechanical wear problem. Electronic throttle control system is mainly composed of accelerator pedal, pedal displacement sensor, ECU (electronic control unit), data bus, servo motor and throttle actuator. The displacement sensor is installed in the accelerator pedal to monitor the position of the accelerator pedal at any time. When it is detected that the height position of the accelerator pedal changes, the information will be sent to the ECU instantly. The ECU will calculate and process these information and data information from other systems to calculate a control signal, which will be sent to the servo motor relay through the line. The servo motor drives the accelerator actuator, and the data bus is responsible for the communication between the system ECU and other ECU. Because the electronic throttle system adjusts the throttle through ECU, various functions can be set to improve driving safety and comfort, among which ASR (traction control system) and speed control system (cruise control system) are the most common. In the current EFI engine, electronic throttle can further improve the fuel saving and emission performance of the engine, because it controls the door of engine power adjustment. So the electronic throttle can play many roles. We know that controlling the throttle opening can control the flow of combustible mixture and change the speed and power of the engine to meet the needs of automobile driving. The traditional engine throttle control mechanism works through a cable (soft steel wire) or a pull rod. One end of the cable is connected with the accelerator pedal, and the other end is connected with the accelerator linkage plate. However, the application of this traditional throttle valve is limited and lacks accuracy. With the rapid development of automotive electronic technology, Electronic Throttle (EGAS) came into being. Compared with the traditional throttle, the obvious point of electronic throttle is that it can replace cable or pull rod with wire harness, install micro-motor on the throttle side, and drive the throttle opening with motor. The so-called "wire transmission" means replacing the original mechanical transmission mechanism with wire. But this is only the surface of the electronic throttle, and its essence and function are not enough to be analyzed only by connecting lines instead. Electronic throttle control system is mainly composed of accelerator pedal, pedal displacement sensor, ECU (electronic control unit), data bus, servo motor and throttle actuator. The displacement sensor is installed in the accelerator pedal to monitor the position of the accelerator pedal at any time. When it is detected that the height position of the accelerator pedal changes, the information will be sent to the ECU instantly. The ECU will calculate and process these information and data information from other systems to calculate a control signal, which will be sent to the servo motor relay through the line. The servo motor drives the accelerator actuator, and the data bus is responsible for the communication between the system ECU and other ECU. Because the electronic throttle system adjusts the throttle through ECU, various functions can be set to improve driving safety and comfort, among which ASR (traction control system) and speed control system (cruise control system) are the most common. When the ASR system senses the wheel speed, the ECU calculates the slip rate according to the position of the accelerator pedal, the wheel speed and the steering angle of the steering wheel, and adjusts the mixture flow by reducing the throttle opening to reduce the engine power and achieve the control purpose. In ASR system, electronic throttle plays a key role, which involves the functions of speed control and idle speed control in the whole ASR system, so that the system can execute instructions quickly and accurately. That is, when the electronic throttle system receives the instruction from ASR system, its instruction for throttle control only comes from ASR, which can avoid the driver's misoperation. When the driver uses the speed control system, the speed sensor inputs a speed signal to the ECU, and then the ECU outputs an instruction to the servo motor to control the throttle opening. In such a system, the throttle opening of the engine is automatically adjusted by the control system according to the change of driving resistance to keep the driving speed stable. Therefore, the electronic throttle system can also be compatible with the cruise control function. In the current EFI engine, in addition to the above functions, the electronic throttle can further improve the fuel saving and emission performance of the engine, because it controls the door of engine power adjustment. So the electronic throttle can play many roles. I'm afraid many friends are not interested in technical details, so I'll simply talk about what role the electronic throttle can play in polo: 1, which is more fuel-efficient than the traditional throttle; 2. Full combustion and cleaner emission; 3, causing the throttle to lag! This is not an advantage! ! Other things like ASR (traction control system) and speed control system (cruise control) are meaningless without our car. All the students who drive the electronic throttle of Chery A3 have the same feeling, and no matter how you drive it, you won't have a strong feeling of pushing back. Even if you step on the bottom to accelerate the floor oil, the speed will hesitate for a while and then slowly accelerate linearly. This is all because A3 uses an electronic throttle, and the acceleration is inherently delayed. Unlike some old cars, A3 uses a cable accelerator (some new cars now use cable). A 4S person once told me that the electronic throttle controller used in A3 is the same as that used in Audi A6. If what is said is true, it is normal. Audi A6 belongs to administrative vehicles, buses and commercial vehicles, which require comfort and smoothness. What matters is the linearity of the acceleration. If A3 uses the same electronic throttle, then the feeling of pushing back is completely suffocating under normal circumstances. Compared with the old-fashioned cable throttle, the biggest feature of electronic throttle is that it can control the throttle opening through ECU, rather than the driver directly controlling the throttle opening through the accelerator pedal. Obviously, this control mode through ECU can realize active control, and the action of throttle valve will not be completely the response of driver's action. The traditional cable accelerator has one end connected to the accelerator pedal and the other end connected to the throttle through a steel wire, and its transmission ratio is 1: 1. That is to say, the throttle opening is the angle we step on with our feet, but in many cases, the throttle should not be opened at such a large angle, so the throttle opening at this time is not necessarily the most scientific. Although this method is direct, its control accuracy is poor. The electronic throttle controls the opening of the throttle through cables or wire harnesses. On the surface, the traditional throttle cable is replaced by cable, but in essence it is not only a simple change of connection mode, but an automatic control function for the power output of the whole vehicle. When the driver steps on the accelerator when he needs to accelerate, the pedal position sensor will transmit the sensed signal to the ECU through the cable. After analysis and judgment, ECU will send instructions to the driving motor, and the driving motor will control the opening of the throttle valve to adjust the flow of combustible mixture. Under heavy load, the throttle opening is large, and a large amount of combustible mixture enters the cylinder. If the cable throttle is used, the throttle opening can only be controlled by stepping on the depth of the accelerator pedal. It is difficult to adjust the throttle opening to reach the theoretical air-fuel ratio, but the electronic throttle can analyze and compare all kinds of data collected by sensors through ECU, send out instructions to make the throttle actuator act and adjust the throttle to the optimal position, so as to reach the theoretical air-fuel ratio 14.7: 1 under different loads and working conditions, and make the fuel burn fully. In daily driving, we will meet some novice or unskilled drivers, who will suddenly step on the accelerator because of improper operation or some excessive drivers. We know that this operation is unscientific, which is not only bad for fuel economy, but also harmful to the engine. The throttle valve suddenly opens, which is the maximum load state of the engine. Full load will cause insufficient combustion of the engine, at the same time, the fuel injector will also increase the fuel injection, resulting in fuel waste, increasing engine load, shortening engine service life, and is not conducive to environmental protection. ECU can't control the throttle of the vehicle when the throttle is pulled, so it can only acquiesce in this misoperation, and at most it will make some adjustments in fuel injection, but it still can't solve the fundamental problem. For the electronic throttle, this is a piece of cake. At this time, the ECU will think that this is the driver's unscientific driving behavior, so it will issue an instruction to open the throttle at a certain speed, instead of synchronizing with the speed at which the driver steps on the throttle. This can not only protect the engine and improve fuel economy, but also make the driver feel very stable and impact-free, and improve the comfort of passengers. We can understand throttle as throttle (although it is not strictly correct, the actual effect is the same). The accelerator pedal of the electronic accelerator is a "fake accelerator", just a receiver. After receiving the driver's action of stepping on the accelerator, he will transmit the data such as the strength and amplitude of the action to the control unit for analysis, and then summarize the driver's intention of stepping on the accelerator, and then the control unit will control the accelerator motor to work according to the calculated actual accelerator opening instruction. It's easier to pull the throttle. There is a "line" directly connected to the throttle valve of the pedal. How much you step on, how much the throttle opens. Electronic throttle can judge the driver's intention according to the details of the action range of stepping on the throttle, so as to realize accurate control. Its advantage is that it will save fuel, be smoother, and be less prone to flameout and rush. One of his shortcomings is expensive, the other is delay, and the response is not as fast as the network cable. Third, the structure is complex and there is a problem of failure rate. The advantage of pulling the throttle is that it is direct and cheap, and the structure is very simple and basically won't break. The disadvantage is that the control is not accurate enough. A typical performance is that if the car with the throttle is small in displacement and low in idle speed, it is easy to stall at first, because you can't control the throttle accurately by hand. In fact, the effect of electronic throttle and cable throttle in actual use is better than that of cable, because the cable is directly reflected, so it is there as soon as you step on it. Unlike electronic throttle, Carnival is an example, and it is very fierce. Some cars still insist on using the cable throttle, because in some games that emphasize explosive power, there is a loss of 0. 0 seconds by using the electronic throttle is basically the decisive factor. But why is the electronic throttle good? The key is not the advantages listed above, but because the control of the electronic throttle is connected to the ECU and becomes a part of the electronic control of the whole vehicle, and the cable throttle is always outside the electronic control system of the whole vehicle. The biggest problem is that the cable throttle cannot be equipped with modules such as cruise control. Just like why drum brakes are eliminated, in fact, if heat exhaustion is not considered (the influence of heat exhaustion is really small in general driving environment), there is not much difference between using and using disc brakes of the same level. The drum brake can't be equipped with ESP (not if one of the four wheels is a drum brake), and the scanning frequency of the same ABS on the drum brake is only one third of that of the disc brake, which is the biggest disadvantage that the drum brake is doomed to be eliminated. Pull the throttle and drum brake, they are eliminated because they can't keep up with the development of other technologies. Simply put, the cable accelerator is purely mechanical, and the throttle control mechanism works through a cable or pull rod. One end of the cable or pull rod is connected with the accelerator pedal, and the other end is connected with the accelerator linkage plate. The electronic throttle is controlled by ECU computer and electronically controlled. When riders get together, I test drive my friend's Geely Emgrand EC7, using a pull-out throttle, which shows the advantages in power. The throttle is available at once, and the feeling of pushing back is available at any time, and I have experienced the carefree power that A3 does not have. By the way, this car is not easy to drive, the clutch is high and hard, the brake throttle is not stable, it is very tired to drive, the shift is also hard, the trip is short, the shift feeling is not clear, and I am always worried about hanging the wrong gear. Maybe it's because I am used to driving A3. It's so comfortable Is there any way to change the delay of the electronic throttle? Electronic throttle accelerator came into being: the principle of electronic throttle accelerator is simply put, electronic throttle accelerator was born to alleviate throttle lag. According to the characteristics of electronic throttle, electronic throttle has the following advantages: (1) amplifying throttle signal and improving static response. The so-called "acceleration" of electronic accelerator is mainly realized by improving the sensitivity of throttle response, which will amplify the input throttle signal by 50%. That is to say, at any time, the last 33% throttle signal is useless, and the throttle output is full throttle when the driver depresses the pedal 66%, which improves the throttle response sensitivity by 50%. However, the electronic throttle does not reduce the classification of throttle signals as many people say. In fact, the throttle signal is infinitely adjustable, only from the previous 1: 1 to 1. X is the amplification factor of the signal. (2) The acceleration of the acceleration signal is amplified to improve the dynamic response. When the accelerator pedal is depressed, the accelerator will calculate the change rate of the accelerator signal according to the depressed amplitude and time. The faster the change, the stronger the acceleration demand, and the accelerator will increase the change rate, and the final effect is better speed-up power. (3) Provide the wrong driving mode for ecu to adjust engine parameters. The electronic control unit of modern engines usually has the ability to adapt to the driving style. If the driver often steps on the accelerator quickly and deeply (commonly known as pulling speed), ecu will gradually think that the driver's style tends to be "intense", so that the engine will slowly adjust the accelerator and fuel injection system to obtain the best adjustment parameters of the engine under this style. After using the electronic throttle, even if the engine is driven according to the previous "gentle" driving style, the engine will still get a "fierce" driving experience, which is equivalent to cheating the ecu. Over time, the engine will automatically modify its parameters to adapt to this style. After installing the electronic throttle, the throttle may be too sensitive, the car is difficult to control, the maneuverability decreases, and the fuel consumption will definitely increase. Therefore, it is not recommended to install an electronic throttle on A3. Although A3 doesn't have a strong feeling of pushing back, which is related to the vehicle weight and engine displacement, its acceleration is linear and it lacks power in the initial stage. However, if you want to speed up, the stamina is still quite sufficient. Friends who are dissatisfied with A3 power suggest (all of them have been trained below): 1, and change to high-flow air filter (increase horsepower). 2. Rectifier (conducive to low-speed combustion and low-torque stable output). 3. Change the air inlet twice (increase horsepower). 4. Replace all synthetic engine oil (reduce the useless consumption of the engine, thus increasing the horsepower) 5. Replace the iridium spark plug (it has little effect on power improvement, but the benefits are the same as 2).