What is the Function of a Car Exhaust Valve?

[Doug]

The function of a car exhaust valve is to allow a portion of the exhaust gases to recirculate back into the combustion chamber. This small amount of exhaust gas helps lower the temperature inside the cylinder during combustion. Since NOX (nitrogen oxides) are produced under high-temperature and oxygen-rich conditions, this process inhibits NOX formation, thereby reducing NOX emissions in the exhaust. Hazards of a Damaged Exhaust Valve: It loses its oil-gas separation function, causing oil to be sucked into the combustion chamber along with the intake air. This leads to oil burning and blue smoke emissions. Additionally, if the exhaust valve malfunctions or is damaged, it cannot properly control the exhaust gas recirculation rate. Excessive exhaust gas recirculation affects the air-fuel mixture concentration, resulting in difficulties starting the engine, engine shaking, unstable idling, poor acceleration, and overall reduced engine performance. Causes of Exhaust Valve Damage Include: Poor quality of the exhaust valve itself. Improper maintenance. Low-quality fuel.