What are the main components of the idle speed control system?

Idle speed control system consists of sensor, ECU and actuator. Among them, the executive mechanism of the idle speed control system is the idle speed control valve (ISCV). The basic principle of idle speed control system is that the engine control system has the function of maintaining normal idle speed, that is, idle speed control function. The traditional idle speed control mode is original manual control or mechanical control, while modern new cars usually adopt ECU intelligent control. The ROM of the engine control module ECU stores the optimal idle speed (target speed) in various idle states. When the engine is idling, the ECU determines the target speed according to the engine state parameters detected by the sensor, calculates the difference between the target speed and the actual speed, determines the control quantity, drives the idling control device, makes the actual speed close to the target speed, and changes the intake air. The control mode of idle speed control system is divided into two parts according to the control mode. One is the throttle direct-acting type, which controls the closed position of the throttle. The actuator adjusts the throttle opening through the throttle control mechanism to achieve the purpose of controlling the idle air intake. The other is the bypass air type, which controls the air flow of the throttle bypass channel. The actuator adjusts the air intake of the bypass air passage by changing the position of the bypass control valve, thus realizing idle speed control. Both of these forms control the airflow by adjusting the cross-sectional area of the intake passage to achieve the purpose of idle speed adjustment.