What is the function of the EGR valve?
1 Answers
The function of the Exhaust Gas Recirculation (EGR) system is to reduce the emission of nitrogen oxides (NOX) in the exhaust. When the engine is operating under load, the EGR valve opens, allowing a small amount of exhaust gas to enter the intake manifold and mix with the combustible mixture before entering the combustion chamber. During idle, the EGR valve closes, and almost no exhaust gas is recirculated back into the engine. The EGR system primarily works through the following principles: 1. The CO2 and water vapor in the EGR significantly increase the specific heat capacity of the working medium. 2. The addition of exhaust gas also dilutes the oxygen concentration in the original mixture, slowing down the combustion speed. 3. It reduces both the peak and average temperatures during combustion, disrupting the favorable conditions for NO formation, thereby greatly reducing NOX emissions.