Structure and function of idle speed control valve

The idle control valve is located on the throttle body. When idling, the throttle valve is almost completely closed. The types of idle control valves include mechanical type, solenoid valve type, rotary valve type and stepping motor type. Because of their different principles and structures, there are many kinds. When the idle load of the engine increases, ECU will control the idle control valve to increase the air intake, so as to improve the idle speed and prevent the engine from being unstable or flameout; When the engine idle load decreases, ECU will control the idle control valve to reduce the intake air, thus reducing the idle speed and preventing the idle speed from being too high. The idle speed control valve is installed on the vent hole next to the throttle. According to the ignition signal, the idle speed controller will make the idle speed control valve act in time when the engine speed is lower than 750 rpm to increase the engine speed, and stop acting when the engine speed exceeds 1050 rpm. In vehicles equipped with air conditioning system, this control valve is also called idle acceleration valve. When the air-conditioning compressor operates, it will produce engine load, reduce the engine idle speed, and the idle speed control valve will act accordingly to keep the idle speed stable. When the working parameters of the engine deviate from the normal value, the idle speed control valve adjusts the idle speed by controlling the amount of air bypassing the throttle body. After the engine is started, the idle speed control valve will be opened for a period of time, and the increase of air intake will increase the engine idle speed by about 150 -300 rpm. When the engine coolant temperature is low, the idle speed control valve will open to obtain a suitable fast idle speed. According to different coolant temperatures, the computer controls the position of the plunger of the idle control valve by changing the signal intensity transmitted to the idle control valve. The electromagnetic idle control valve is actually an electromagnetic coil. The ECU controls the current of the coil and the opening of the control valve through the duty ratio. Rotary valve idle speed control valve is an electric idle speed control valve. The idle speed control valve of stepping motor is the most widely used. It can adjust the idle speed by controlling the amount of air bypassing the throttle to achieve the ideal idle speed. In addition, there is a paraffin idle speed control valve, which mainly uses the principle of paraffin low temperature opening to improve the idle speed of the engine. As the temperature increases, the slide valve decreases to stabilize the idle speed. The idle speed control valve is also equipped with an idle speed adjustment screw for adjusting the idle speed.