What is the working principle of the EGR valve

EGR is the abbreviation of engine exhaust gas recirculation system, and the EGR valve is a main control part in the entire EGR system. The working principle of the EGR system is to cool the exhaust gas in the engine exhaust pipe through the pipeline and radiator, and then enter the engine intake system through the EGR valve. After the exhaust gas and air are mixed, it enters the cylinder and burns, because part of the exhaust gas participates in the combustion. , Can effectively reduce the formation of nitrogen oxides in the exhaust of the engine, lower the combustion temperature of the engine, and achieve the effect of reducing the exhaust emissions of the engine.
The EGR valve is generally intervened in the engine's mid-to-high speed range. When the engine is idling and low-speed, the EGR system does not work. The EGR valve is controlled by a computer. This can accurately control the amount of exhaust gas entering and prevent the exhaust gas from entering. Mostly affect the normal operation of the engine.