Working principle of electronically controlled fuel injection system for Bosch me744 engine

Structure and working principle of electronically controlled gasoline injection system for engine

1. Structure of electronically controlled gasoline injection system of engine

The function of the electronically controlled gasoline injection system of the engine is to detect the working condition of the engine and accurately control the fuel injection quantity and timing. It is mainly composed of various sensors, various actuators and controllers (also called electronic control unit ECU).

The function of the sensor is to convert the working condition and state of the engine, the driving condition and state of the automobile and other physical quantities into electrical signals and transmit them to the ECU. Mainly through the air flow sensor. Crankshaft position sensor, engine speed sensor, throttle position sensor, oxygen sensor and knock sensor.

Actuator is used to execute various control instructions issued by engine ECU, mainly including electric fuel pump, fuel injector, idle speed control (ISC) valve, exhaust gas recirculation (EGR) valve and self-diagnosis system.

Controller is the core of electronic control system, which is mainly composed of central processing unit (CPU), random access memory (RAM), read-only memory (ROM), input-output interface circuit, driving circuit and engine control program solidified in ROM.

2. Working principle of engine electronic control system

Take the AJR engine of Santana 2000GSI car as an example, it adopts the motrornic-3.8.2 electronically controlled sequential multipoint fuel injection system (hereinafter referred to as the electronic control system) of BOSCH company in Germany. The fuel system and ignition system are controlled by the same electronic control unit (ECU)j220, and there is no distributor ignition system. The system uses a thermal air flowmeter to detect the intake flow of the engine, which can directly reflect the load of the engine. The crankshaft of the engine is equipped with a 1 signal trigger wheel with 60 teeth, which is used to silence the crank angle signal. The electronic control system can accurately control the air-fuel ratio and ignition time of the engine mixer according to the intake flow signal and the crank angle signal, thus greatly reducing the automobile exhaust pollution.