Automobile electromechanical integration-car electronics is gradually becoming the basic feature of modern cars (especially cars). Engine electronic control is an important part of automobile electronic control. In order to adapt to the increasingly strict emission and safety regulations, it has been highly valued by domestic and foreign automobile manufacturers and has achieved unprecedented development. I. Overview The theoretical basis of modern car electric control technology is modern control theory. From the early classic control to the current intelligent control, the control theory has been widely used in automotive electronic control. There are PID control, optimal control, adaptive control, sliding mode control, fuzzy control, neural network control and predictive control. The development of modern control theory makes the electronic control system more adaptable to complex multivariable systems, time-varying systems and nonlinear systems. Even systems with less precise mathematical models can implement accurate and effective control. This is the prerequisite for the electronic control of the engine. In terms of its structure, the electronic control system is mainly composed of three parts: sensors, electronic control components (ECU), and actuators. The sensor is used as an input part to measure physical signals (temperature, pressure, etc.) and convert them into electrical signals; the role of the ECU is to receive the sensor's input signal and perform calculation processing according to the set program to output the processing results; Then the actuator is driven according to the electrical signal output by the ECU to change it as required. (1) Electronic Control Unit (ECU) The ECU is centered on a microcomputer. It also includes a front-end A / D converter, a digital signal buffer, and a rear-mounted signal amplifier. The microcomputer has fast calculation speed, high precision, real-time control, and multiple interrupt response functions. In addition to 8-bit and 16-bit microcomputers, 32-bit and 64-bit microcomputers have been gradually used. Moreover, not only general-purpose microcomputers and single-chip microcomputers, but also special automotive microcomputers have been developed. It is the rapid development of microcomputer technology that promotes the continuous improvement of automotive electronic control technology. It can be said that the current general trend of ECU development is the transition from single-system single-machine control to multi-system centralized control. In the near future, the automotive electronic control system will use computer network technology to connect the ECUs of the engine electronic control system, body electronic control system, chassis electronic control system, and information and communication systems to form a distributed computer network inside the machine Comprehensive control of automotive electronics. (2) Sensor The working conditions of automotive sensors are extremely harsh, so whether the sensors can work accurately and reliably is crucial. In recent years, in this field, theoretical research and material application have developed rapidly, and semiconductor and metal film technology, ceramic sintering technology, etc. have developed rapidly. There is no doubt that intelligence, integration and digitization will be the future development trend of sensors. (3) Actuator The actuator is used to accurately execute the command signal issued by the ECU. Therefore, the accuracy of the actuator work will ultimately affect the success or failure of the electronic control. Because of this, its work reliability and accuracy have always been the focus of research. At present, there are many types of actuators in automotive electronic control systems, including solenoid valves, motors, piezoelectric elements, igniters, electromagnetic relays, thermocouples, etc., and their structures and functions are not the same. The development direction of actuators is intelligent actuators and solid-state intelligent power devices. 2. Engine Electronic Control Technology and Application Engine electronic control technology can be divided into electronically controlled gasoline injection, electronic ignition, idle speed control, exhaust gas recirculation control, supercharging control, fault self-diagnosis, fault insurance, backup control and other control technologies. (1) Electronically Controlled Gasoline Injection (EFI) System The electronically controlled gasoline injection system (referred to as the electronic injection system for short) was developed in the late 1960s. Compared with the carburetor fuel supply system commonly used in the early days, its outstanding advantage is that the control of the air-fuel ratio is more precise, and the best air Fuel ratio; and electronic injection technology improves gasoline atomization and evaporation performance, better acceleration performance, engine power and torque increased significantly. At present, the EFI system mainly uses a combination of open-loop and closed-loop control (feedback control). Open-loop control is adopted for operating conditions such as warm-up, idling, etc. that require rich supply. In addition, the actual air-fuel ratio is measured by an oxygen sensor provided in the exhaust pipe for feedback control. The intake air volume is measured by the air flow meter or the absolute pressure sensor and the speed sensor of the intake manifold. The ECU determines the appropriate air-fuel ratio according to the cooling water temperature, intake air temperature, and oxygen sensor signal, etc., calculates the required fuel injection amount, and then Actuator (injector and circuit disconnect relay) controls. According to the different installation positions of the fuel injectors, the electric injection system can be divided into three types: single point injection (SPI), multi-point injection (MPI) and direct injection in the cylinder. 1 to 2 injectors for single-point injection are installed at the throttle of the intake pipe. In multi-point injection, each injector is installed in the intake manifold of each cylinder, so that the mixture of each cylinder is evenly distributed, so it is widely used in cars. In addition, according to the different injection timing, multi-point injection can be subdivided into three types: simultaneous injection, group injection and sequential injection. The sequential injection enables the injector to inject fuel according to the ignition sequence of each cylinder. Once, this method is better than the first two applications. In-cylinder direct injection, especially four-stroke gasoline engine in-cylinder direct injection is the cutting-edge technology in gasoline injection of current cars. It was first developed by Mitsubishi Corporation in Japan. Its fuel injector is installed on the cylinder head and directly injects gasoline into the cylinder during work Perform mixed combustion. The realization of direct injection technology has greatly reduced the fuel consumption of gasoline engines, and the more powerful point injection is more superior; at the same time, in conjunction with other mechanisms, the high air-fuel ratio lean combustion technology can be realized. (2) Electronic ignition control system As early as the early 20th century, the ignition system has been applied to automobile engines, from contact type, ordinary non-contact type, integrated circuit type, to the development of today's computer-controlled electronic ignition system. The computer-controlled electronic ignition system can control and maintain the engine ignition advance angle (ESA) within the optimal range, so that the ignition timing of the gasoline engine is closer to the ideal state, and further tap the potential of the engine. In the microcomputer-controlled ignition system, there is currently a distributorless ignition (DLI) system, which cancels the distributor in the ordinary microcomputer-controlled ignition system and changes the internal power distribution of each cylinder by the ECU. In this way, the high-voltage electricity generated by the ignition coil is directly sent to the spark plug for ignition without being distributed through the distributor. The non-distributor ignition system can eliminate the spark discharge phenomenon of the distributor head and the electrode on the cover side of the distributor, and reduce electromagnetic interference. Distributorless ignition system has two types of ignition at the same time and independent ignition of each cylinder according to the different ignition sequence. In the two-cylinder simultaneous ignition mode, one ignition coil is used for each two-cylinder group, and all cylinder bodies are divided into several groups to ignite sequentially according to the group; in the independent ignition mode of each cylinder, the spark plug of each cylinder is provided with a separate ignition coil (Especially with the appearance of the ultra-small plastic packaging ignition coil, making it integrated with the spark plug), so that each cylinder can turn on ignition in turn. In the ignition control of the engine, a combination of open-loop and closed-loop control is also used. The ignition timing in the starting phase is controlled by a special signal in the ECU. During normal operation, the knock feedback control is performed by adding a knock sensor, and the ignition timing is adjusted according to the feedback signal of the knock sensor so that the engine is in a critical knock state. Guangzhou Lufeng Electronic Technology Co. , Ltd. , https://www.lufengelectronics.com