The control system of electronically controlled engine is simply composed of three parts: sensor, electronic control unit ECU and actuator, in which ECU undertakes? Brain? Function, as far as use is concerned, is a microcomputer controller dedicated to the engine. Like ordinary computers, it consists of microprocessor (CPU), memory (ROM, RAM), input/output interface (I/O), analog-to-digital converter (A/D) and large-scale integrated circuits such as shaping and driving.
When ECM is working, the working state information of various parts of the engine is collected through various sensors (including temperature sensor, pressure sensor, speed sensor, flow sensor, position sensor, oxygen sensor, knock sensor, etc.). ) and send it to ECU through transmission line. After receiving these signals, ECU will analyze all kinds of signals, and then know what state the functions of engine components are in and how they operate. The program stored in ROM is written on the basis of accurate calculation and a large number of experimental data graphs. This inherent program is constantly compared and calculated with the signals collected from various sensors when the engine is working. The results of comparison and calculation are used for closed-loop control of engine ignition, air-fuel ratio, idle speed and exhaust gas recirculation. (Photo/Text/Photo: Pacific Auto Network Dong Peng)