Introduction of Idle Air Control Valve

FOR IMMEDIATE RELEASE
San Francisco, California, United States of America (Free-Press-Release.com) September 1, 2011 -- Idle air control valve owns throttle's bypass airway function. Besides that, under the control of the ECU, it can change the air volume entering the engine in terms of the engine's actual working condition. For example, the engine friction torque changes or other factors cause the engine's idle speed change, ECU can maintain a constant speed according to the received speed signal to control ISCV's opening.

Idle air control valve is installed in the bypass air hole of the throttle. According to the ignition signal, idle air control valve is controlled by the idle speed controller, when the engine speed is lower than 750RPM, it is time for the idle air control valve to take action so as to upgrade the engine speed. When the engine speed is over 1050RPM, idle air control valve will stop functioning. In the vehicles equipped with air-conditioning systems, idle air control valve is called as idle speed control valve. The reason is as follows, after air compressor is functioning, it will lead to the engine loaded, which can make the engine idling reduction, while idle air control valve is thus functioning along with these actions so as to maintain the idle stability.

In the cold start, the engine temperature is low, and the frictional resistance is also big. To reduce engine's warm-up time for the engine, the engine is gained the additional air through the idle air control valve (air volume is measured by the air flow sensor), the engine thus increases idle speed so that it can reduce the warm-up time. After the engine becomes warm, the air flowing through the idle air control valve is thus cut off, the inhaled air in the engine is changed to be supplied by the bypass channel in idle air control valve, so that the engine can be turned into the normal idle operating.

The common idle air control valve has two kinds of forms, namely, double-metallic-piece idle air control valve and paraffin idle air control valve. Paraffin idle air control valve is installed in the throttle, it controls the air bypass airway's cross-sectional area according to the engine cooling water temperature, while its control ability is from thermostatic paraffin's ability of thermal expansion and contraction. Importing engine's cooling water is the necessary condition in this form of the idle air control valve. In order to simplify the structure, most of paraffin idle air control valves use the cooling-pipe integrated structure.

What's more, the paraffin idle air control valve's specific operation is as follows, when the engine's cooling water temperature is low, the thermostatic paraffin would contract, the poppet valve would open under the action of the spring. With the increase of the temperature, the thermostatic paraffin would expanse, and thus pushing the connecting rod to make the poppet valve slowly closed, the engine's idle speed would thus slow down. After the engine is warmed, the poppet valve will completely close the air channel, the engine will be returned to normal idle speed.

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