What is the working principle of an engine exhaust valve?
1 Answers
High-pressure gas (gaseous working medium and lubricating oil) 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 vane. Through centrifugal force and gravity, the lubricating oil is separated from the working medium gas and flows down along the inner wall of the cylinder. The working medium gas is then discharged from the exhaust valve through a multi-hole baffle via the central pipe. The separated lubricating oil accumulates at the bottom of the oil separator and can be periodically drained or automatically returned to the compressor's crankcase using a float valve. Symptoms of a damaged exhaust valve: 1. Affects engine performance: When the exhaust valve is damaged, it cannot control the amount of exhaust gas recirculation. Excessive exhaust gas participating in recirculation will affect the concentration of the air-fuel mixture, leading to issues such as difficulty starting, engine shaking, unstable idle speed, and weak acceleration, which impair engine performance. 2. Oil burning and blue smoke: A damaged exhaust valve can cause the engine to burn oil, resulting in blue smoke from the exhaust pipe. The exhaust valve functions to separate oil and gas; under normal operation, it only draws in exhaust gas and not oil. When the exhaust valve is damaged, it loses its oil-gas separation function, potentially drawing in oil along with the gas, allowing oil to enter the combustion chamber and causing oil burning and blue smoke.