Application of Automotive Electronic Control Technology in Automotive Safety

Abstract: With the improvement of people's living standards and the maturity of automobile production and assembly technology, cars have gradually entered the ordinary family. As the most important means of transportation in modern society, the automobile not only brings speed, but also gives people the respect and pursuit of quality life. At the same time, it also brings many security risks. The data shows that in 2011, the number of deaths caused by traffic accidents in China was 62,000, and the death rate from traffic accidents ranked first in the world. Therefore, car safety is becoming more and more important.

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1 Introduction

With the rapid development of electronic information science and technology in recent years, intelligent electronic technology has been promoted from the field of traditional household appliances to the field of automotive intelligent control, greatly improving the comfort, operability and safety of automobiles. Since the German Carl Fritridge Bentz invented the world's first three-wheeled car in 1886, car safety and car development have followed. The safety of car driving in today's society is the most concerned issue for consumers. A Visteon company conducted a survey that showed that car safety is at the core of customer demand for cars. Most consumers believe that car safety is more important than car power, comfort and economy. Focus on car safety, not only for drivers and passengers, but also for more people on the road. This article will introduce the application of in-vehicle intelligent electronic control technology to improve the safety control technology of car safety with easy-to-understand text.

2. Automotive electronic anti-skid control system

The automotive electronic anti-skid control mainly includes three aspects of control: anti-skid, anti-skid and anti-skid. The car anti-skid control system is a safety accessory on the car that protects passengers and vehicles from side slip, deviation, loss of steering and slippage during braking, starting, acceleration and steering. The role of greatly reducing the probability of traffic accidents caused by braking, driving, etc.

2.1 Anti-locked Braking System (ABS)

When the car is braking, the tires provide friction to stop the car. And because the static friction (tire rotation) is much greater than the sliding friction (tire slip), the ABS system allows the car to get more friction to stop it faster. The anti-lock brake system (ABS) of the automobile brake is used when the vehicle is in emergency braking on any road surface. The intelligent electronic system of the vehicle receives the signal of the wheel speed sensor, automatically controls and adjusts the braking force of the wheel, so that the wheel is in rotation and sliding. The critical state prevents the wheels from being completely locked, so that the wheels get the maximum braking friction and get the best braking effect. In this way, the deviation, side slip, and loss of steering ability during braking are avoided, and the handling performance and stability performance of the automobile are improved (as shown in FIG. 1). At the same time, the car can also obtain the maximum braking force, shorten the braking distance by 30%, improve the braking performance of the car, and is of great significance to ensure the safety of the car.

In short, the era of “artificial brakes” has passed, and the highly intelligent ABS gives us a lot of protection in driving safety. Shortening the braking distance by 30% will undoubtedly become a life-saving straw in many cases. The brakes ensure that the direction is controllable and provide driving protection.

2.2 AccelerationSlip Regulation (ASR)

When the car starts or accelerates, especially when driving on special roads with less friction such as rain, snow, hail, road freezing, etc., the driving wheel slipping often occurs, which is very dangerous on the mountain road. In order to ensure the safety and stability of the car, the control wheel does not slip, mainly receives the wheel speed sensor signal through the vehicle vehicle intelligent control unit, controls the electronic ignition part of the engine and the oil supply, usually by changing the throttle opening and the ignition advance angle. The way to adjust the output torque of the engine to ensure maximum adhesion and traction between the wheel and the ground, so that the slip rate of the wheel reaches the optimal range (15% ~ 20%). If the wheel slips out of control, the car will lose control. Therefore, don't think that the wheel will be dangerous when it is braked. The wheel will slip when it starts.

2.3 Vehicle Electronic Stability System (ESP)

Vehicle Electronic Stability System (EPS) When the vehicle is turning, braking or slipping, the electronic control unit ECU receives the steering angle sensor (the steering angle for detecting the steering wheel), the wheel speed sensor (monitoring the rotational speed of each wheel), G (Skip) sensor (monitoring the state of the car body rotating around the vertical axis), yaw rate (lateral acceleration) sensor (measuring the centrifugal force when the car turns), deceleration sensor, analyzing, calculating and judging the running state of the vehicle Then, an instruction is issued to transmit the hydraulic pressure generated by the pressure pump in the brake actuator to the wheel cylinder of the corresponding wheel brake. Thereby, the control of the front wheel side slip and the rear wheel side slip is realized, so that the vehicle does not deviate from the correct travel track. For example, when the rear wheel of the car is skidding, the ESP system immediately applies the braking force to the outer front wheel that is turning, and quickly braking the front wheel to produce an opposite torque to ensure that the car is in the original lane. Driving; when the front wheel of the car is "floating". The ESP system applies braking force to the two rear wheels and quickly brakes the rear wheels to keep the car in the original lane. It is not difficult to see that the vehicle electronic stability system (EPS) is a further extension of the traditional ABS (anti-lock braking system), ASR (drive anti-skid system), the most important feature of ESP is its initiative, if ABS is passively reacting Then ESP can prevent it from happening. More intelligent to improve the stability and safety of the car.

2.4 Emergency Brake Aid System (ElementalBattle Academy, referred to as BAS)

Since a large number of drivers will be indecisive in an emergency, braking measures cannot be effectively taken. Braking system performance can not be effectively played, the braking distance is significantly extended. In order to shorten the braking distance in the case of emergency braking, Mercedes-Benz has developed a brake assist system (BAS). Since 1997, this system has become the standard assembly for all Mercedes-Benz cars. The specific workflow is shown in Figure 2.

Mercedes-Benz has thoroughly tested the function and mode of operation of the Brake Assist System (BAS). For example: in the driving simulator: here, the driver will encounter a dangerous situation without warning, at which point they must implement emergency braking. On dry roads, if the brake assist system is not used, most testers need a braking distance of up to 73 meters to completely stop the car with a speed of 100 kilometers per hour. With this system, the car stopped completely after only 40 meters. This is equivalent to a braking distance reduction of approximately 45%.

The new car equipped with this system reduced the frequency of accidents by 8 percent in the event of a crash and reduced the frequency of accidents by 30 percent in the case of pedestrian accidents.

3.Airbag protection system (Supplemental InflatableRestraintSystem, SRS for short)

The impact of the car and the obstruction is the first collision, and the impact of the person and the corresponding component on the car is the second collision. Generally, the collision occurs in the first 60 ms of the collision, and the casualty is caused by the second collision. After the first collision of the car occurs, before the second collision occurs, the sensor senses the collision strength of the car and transmits it to the controller. The ECU of the SRS receives and processes the signal of the sensor. When the ECU of the SRS determines that it is necessary to open the airbag, The ignition signal is immediately triggered to trigger the gas generator. After the gas generator is ignited, a large amount of gas is quickly generated and the airbag is quickly deployed. The entire inflation process of the airbag takes about 30 ms to complete the entire working process of the airbag, blocking the occupant (mainly front, side, knee) The collision between the part and the head and the corresponding component in the vehicle absorbs the kinetic energy of the occupant through the damping effect of the exhaust throttle on the airbag, thereby hitting the purpose of protecting the occupant.