What is the working principle of the Passat 1.8T exhaust valve?

[LeKinsley]

Passat 1.8T exhaust valve working principle and function are as follows: Working principle: The high-pressure gas from the compressor enters the exhaust valve and then flows into the guide vane of the exhaust valve, moving in a spiral pattern along the guide vane. Through centrifugal force and gravity, the lubricating oil is separated from the working gas and flows down along the inner wall of the cylinder. The working gas is then discharged from the exhaust valve through the central pipe via multiple baffles. The separated lubricating oil accumulates at the bottom of the oil separator and can be periodically drained or automatically returned to the compressor's crankshaft using a float valve. Function of the exhaust valve: It allows a small portion of the exhaust gas to be recirculated into the combustion chamber. This small amount of exhaust gas lowers the combustion temperature in the cylinder. Since NOX is generated under high-temperature and oxygen-rich conditions, the recirculation of exhaust gas inhibits the formation of NOX, thereby reducing the NOX content in the exhaust emissions.