What is an EGR Valve?

[LeRicardo]

EGR valve is an exhaust gas recirculation system, an exhaust purification device designed for nitrogen oxides (NOx), one of the harmful gases in engine emissions. Below is an introduction to the EGR system: 1. Function: The main component of the EGR system is the digital control EGR valve, which is installed on the right exhaust manifold. Its role is to independently and accurately control the amount of exhaust gas recirculated back to the engine, regardless of the manifold vacuum level. 2. Working Principle: The EGR valve controls the amount of exhaust gas flowing back from the exhaust manifold to the intake manifold through three metering holes of increasing diameters, creating various flow combinations. Each metering hole consists of a solenoid valve and a needle valve. When the solenoid valve is energized, the armature is magnetically pulled upward, opening the metering hole and the valve. The rotary needle valve ensures excellent sealing when the EGR valve is closed.