Analysis of electronic control technology in automotive electronic systems

The rapid development of automotive electronic control technology mainly depends on the following three factors: First, thanks to the rapid development of transistor technology, large-scale integrated circuit technology, computer technology and network technology, the cost continues to decrease, and the control function becomes more and more powerful, providing good conditions for the development of automotive electronic control technology; second, due to the increasingly stringent regulations formulated by governments of various countries, automobile manufacturers are forced to adopt advanced electronic control technology to meet the regulatory requirements in terms of fuel economy, safety and emission performance; third, users' increasingly high demands for automobile safety, comfort, power, economy, etc. have prompted automobile manufacturers to adopt more electronic control technology and enhance the competitiveness of their products in the market.

The development process of automotive electronic control technology can be roughly divided into three stages: electronic circuit control, microcomputer control, and vehicle-mounted local area network control. The first stage (1953-1975): analog electronic circuit control stage, that is, the use of discrete electronic components or integrated circuits to form electronic controllers for control. Automotive electronic equipment mainly uses discrete electronic components to form electronic controllers, thus opening the prelude to the automotive electronics era.

The second stage (1976-1999): microcomputer control stage, that is, the use of analog computers or digital computers for control, and the development of control technology towards intelligence. Automotive electronic equipment generally uses 8-bit, 16-bit or 32-bit word-length microprocessors for control, and mainly develops and manufactures dedicated independent control systems and integrated control systems. The third stage (2000 to present): vehicle-mounted LAN control stage, that is, the use of vehicle-mounted LAN (Local Area Network) to control automotive electrical and electronic control systems. Domestic and foreign mid- and high-end cars have begun to use vehicle-mounted LAN technology.

Modern cars are increasingly integrating single control systems into centralized control systems. Control system integration can simplify the entire system and facilitate the comprehensive coordinated control of complex systems with multiple variables and multiple targets. However, the integration of control systems requires microprocessors with stronger computing power and faster speeds, so microprocessors have also evolved from 8-bit, 16-bit, and 32-bit to 64-bit.

As the number of electronic devices in cars increases dramatically, car circuits become more and more complex. In order to reduce the number of connecting wires, modern cars widely use vehicle network technology, changing the past dedicated line system of one line for one use to a system of multiple lines for one line. Network technology can be used to connect various electronic control units, smart sensors, smart meters, etc. in the car, thereby forming a controller area network inside the car and realizing information resource sharing among various systems. This not only simplifies wiring, reduces the number of electrical nodes and the amount of wires used, but also increases the reliability of information transmission.

A smart car is a comprehensive system that integrates environmental perception, planning and decision-making, multi-level assisted driving and other functions. It concentrates on the use of computers, intelligent sensors, information fusion, communications, artificial intelligence and automatic control technologies, and is a typical high-tech complex.

Intelligent Transportation System (ITS) is a real-time, accurate and efficient integrated transportation and management system established by effectively integrating advanced information technology, communication technology, sensor technology, control technology and computer technology into the entire transportation management system. The combination of intelligent transportation technology and intelligent automobile technology can realize the automatic selection of the best driving route for automobiles and automatic driving of automobiles. The intelligence of automobiles and transportation represents the development direction of future automobiles and future transportation.

The so-called modular design means that in order to develop different products with multiple functions, it is not necessary to design each product separately, but to carefully design multiple modules and combine them in different ways to form different products, so as to solve the contradiction between product variety, specifications, manufacturing cycle and cost. With the increasingly fierce competition in the automobile market, in order to meet the personalized needs of users, automobile manufacturers need to launch more new models, and the development cycle of new models is getting shorter and shorter. The use of modular design technology of electronic control system can shorten the development cycle, improve the quality of developed products, reduce development costs, and effectively improve the reliability of automotive electronic control systems and even the entire vehicle.

Each electronic control system in a car is composed of three parts: sensors and switch devices, electronic control units and actuators (actuators). These three parts are connected by wires to form an electronic control system. Detect the flow of fluids such as gases and liquids, such as air flow sensors used in engine electronic fuel injection systems; refrigerant flow sensors used in automatic air conditioning systems, etc.

Detect the rotation angle of the rotating object or the displacement of the moving object, such as the crankshaft position sensor, camshaft position sensor, throttle position sensor used in the engine electronic fuel injection and microcomputer controlled ignition system; steering wheel angle sensor used in electronic stability program; vehicle height sensor used in electronic control suspension system; EGR valve position sensor used in exhaust gas recirculation system, etc.

Detect the pressure of the medium being measured, such as the intake manifold pressure sensor, atmospheric pressure sensor, exhaust pressure sensor used in the engine electronic fuel injection system; used for the oil pressure sensor in the anti-skid system, etc. Detect the temperature of the medium being measured, such as the engine coolant temperature sensor, intake temperature sensor, exhaust temperature sensor, fuel temperature sensor used in the engine electronic fuel injection and microcomputer-controlled ignition system; used for the in-vehicle temperature sensor used in the automatic air conditioning control system, etc.

Detect the concentration of the measured medium, such as oxygen sensors used in engine electronic fuel injection systems; alcohol concentration sensors used in safety control systems, etc. Detect the rotation speed of the measured rotating object or the speed of the moving object, such as engine speed sensors used in engine electronic fuel injection and microcomputer-controlled ignition systems; wheel speed sensors used in anti-lock braking systems, vehicle speed sensors used in electronically controlled automatic transmissions, etc.

Detect the acceleration of the object being measured, such as the longitudinal and lateral acceleration sensors of automobiles used in electronic stability programs; the vertical acceleration sensors of the vehicle body used in electronically controlled suspension systems, etc. The automotive electronic control unit is referred to as the electronic control unit, also known as the automotive electronic controller or automotive electronic control component, commonly known as the "car computer". The electronic control unit is an electronic control device composed of a single-chip microcomputer as the core, with powerful mathematical operations, logical judgment, data processing and data management functions.

The electronic control unit is the control center of the automotive electronic control system. Its main function is to analyze and process various information collected by sensors and issue control instructions to the controlled device (i.e. actuator or actuator). The actuator, also known as the actuator, is the actuator of the electronic control system. The function of the actuator is to receive instructions from the electronic control unit (ECU) and complete specific execution actions. The actuators of the automotive electronic control system are usually motors, solenoid valves, etc. Different automotive electronic control systems use different numbers and types of actuators.

The actuators of the engine's electronically controlled fuel injection system include an electric fuel pump and an electromagnetic fuel injector; the actuator of the engine's idle control system is the idle control valve; the actuator of the gasoline evaporative pollution control system's vapor recovery system is the activated carbon canister solenoid valve; the actuators of the microcomputer-controlled ignition system include an ignition controller and an ignition coil; the actuators of the anti-lock braking system include a two-position, two-way solenoid valve or a three-position, three-way solenoid valve, and an oil return pump motor; the actuator of the airbag system is the airbag igniter; the actuators of the electronically controlled automatic transmission include a shift solenoid valve, an oil pressure control solenoid valve, and a locking solenoid valve; the actuators of the automobile's electronically controlled suspension system are an air compressor, a shock absorber damping and spring stiffness adjustment motor, and a height control solenoid valve, etc.