The function of automobile electronic control system is to improve the overall performance of automobile, including power, economy, safety, comfort, maneuverability, passability and emission performance. Although the functions and quantity of the electronic control system are different for different models and grades of automobiles, the basic structure of the automobile electronic control system is composed of sensors (sensing software) and switch signals, electronic control unit ECU and actuator (actuator), which is the same feature of the electronic control system. (I) Engine Electronic Control Technology The engine electronic control technology also contains many contents, mainly consisting of three parts: the engine electronic control fuel injection system, the engine electronic control ignition timing system and the engine idle speed control system. Any equipment controlled by a microcomputer must not be composed of one or three basic components: sensor → control computer → actuator. Sensors are the eyes of computer control system, which are used to observe various physical and chemical quantities and convert these physical and chemical quantities into electrical signals that can be recognized by computers, such as water temperature sensors and air flow meters. Actuator is the hand of computer control system, which is used to execute various commands issued by computer. It can convert commands into specific actions of controlled objects, such as fuel injectors, idle motors, ignition coils, etc. The control computer is the headquarters of the whole control system, which is used to analyze and process all kinds of information, operate various actuators and complete the work of the whole system. (2) Electronic automatic transmission The electronic automatic transmission system, also known as ECT, consists of three subsystems: transmission system, hydraulic system and electronic control system. Among them, the assembly component composed of transmission system and hydraulic control system is usually called automatic transmission. The electronic control transmission consists of three parts: sensor and control switch, electronic control unit ECTECU and actuator. The function of electronic control system of automatic transmission: replacing oil pressure signal with electric signal and shifting valve with crisis treatment can realize the best control of shifting law, timely and accurately, better meet the driving requirements of automobile, help improve the working condition of engine, obtain the best power and economy, and reduce emission pollution. Working principle of automatic transmission electronic control system: the sensor provides signals such as vehicle speed and throttle opening. Based on this, the electronic control unit determines the shift or locking time, and then outputs the corresponding control signal to the solenoid valve. The solenoid valve can control the hydraulic control valve to complete the shift and locking instructions issued by the electronic control unit. The electronic control system is also equipped with a self-diagnosis device, which has the function of keeping the vehicle running for a long time when a fault occurs. (3) The basic composition of the electronic anti-lock braking device ABS: In addition to the original braking system (some vacuum booster devices do not have it), other devices such as hydraulic regulator (with hydraulic oil pump), wheel speed sensor, electronic control unit (ECU) and circuit are added. The function of ABS: 1) Effectively control the wheel slip rate; 2) the braking stability is improved; 3) Have the ability of fault self-diagnosis. The working principle of ABS: the wheel speed sensor detects the wheel speed and inputs the speed signal to ECU. The signal output by ECU alternately opens and closes the oil inlet and outlet valves, so as to control the brake pressure regulator and keep the wheel slip rate around 10%-20%, which is the best braking performance of the automobile and ensures good steering performance under emergency braking. (4) Electronic control airbag airbag composition: collision sensor, airbag ECU, inflation element and airbag. The function of airbag: to reduce the harm of huge inertial force to the driver and passengers in frontal collision. The working principle of airbag: when the car is hit by a high-speed collision in a certain angle range ahead, the collision sensor installed at the front end of the car and the protective collision sensor installed together with the SRS computer will detect the signal of sudden deceleration of the car and transmit the signal to the SRS computer; After mathematical calculation and logical judgment, the pre-designed program in SRS computer immediately sends an ignition instruction to the electric igniter (electric detonator) in SRS airbag module to detonate the electric detonator, and the igniter (priming agent) explodes when heated (that is, the heating wire is energized to ignite the priming agent). When the igniter explodes linearly, a large amount of heat will be generated quickly, and the inflator (sodium azide solid sheet) will release a large amount of nitrogen to rush into the airbag, and the airbag will burst open the decorative cover of the airbag assembly and bulge out to the driver, so that the driver's head and chest will be pressed against the airbag filled with gas, and the collision between the human body and the car parts will become elastic collision, and the kinetic energy generated by the collision of the human body will be absorbed through the deformation of the airbag, thus achieving the purpose of protecting the human body. (4) Electronic control suspension device: sensor, electronic control unit (ECU) and actuator. Function: 1) control of spring elastic coefficient (suspension stiffness) and damping coefficient of shock absorber; 2) Height adjustment function. Working principle: The sensor converts relevant signals into electrical signals and sends them to the electronic control unit, which controls actuators such as air springs to make adaptive adjustment through arithmetic processing to maintain the ride comfort and handling stability of the vehicle.