What is the working principle of the exhaust valve?
1 Answers
The exhaust valve, also known as the oil-gas separator or pressure control valve, is installed between the compressor outlet and the condenser inlet. It improves the heat transfer efficiency in the condenser and evaporator by separating oil and gas, which is particularly important for systems where the lubricating oil and working medium have poor mutual solubility. Working principle of the exhaust valve: The high-pressure gas from the compressor, including gaseous working medium and lubricating oil, enters the exhaust valve and flows into the guide vane of the exhaust valve. The gas spirals along the guide vane, and the lubricating oil is separated from the working medium gas by centrifugal force and gravity, flowing down along the inner wall of the cylinder. The working medium gas is discharged from the exhaust valve through the central pipe via a multi-baffle structure. 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. Function of the exhaust valve: It allows a portion of the exhaust gas to recirculate into the cylinder for combustion. This small amount of exhaust gas lowers the combustion temperature in the cylinder. Since NOX is generated under high-temperature and oxygen-rich conditions, this process inhibits NOX formation, thereby reducing NOX emissions. When the throttle reaches a certain opening, the exhaust valve opens, channeling exhaust gas from the cylinder to the intake pipe, which then re-enters the cylinder for recirculation and combustion. This ensures complete combustion of exhaust gases and purifies the air.
