EGR VALVE for SCANIA

Exhaust Gas Recirculation system is used to reduce the emission of nitrogen oxide in exhaust gas. When the engine is operating under load, the EGR valve opens, allowing a small amount of exhaust gas to enter the intake manifold and enter the combustion chamber with the combustible mixture. At idle the EGR valve is closed and almost no exhaust gas is recirculated to the engine. Automobile exhaust gas is a non-flammable gas and does not participate in combustion in the combustion chamber. It reduces the combustion temperature and pressure by absorbing part of the heat generated by combustion to reduce the amount of nitrogen oxide produced. The amount of exhaust gas entering the combustion chamber increases with the increase of engine speed and load

Exhaust gas recirculation is a method that leads part of the exhaust gas to the inhaled fresh air and returns to the inside of the cylinder for recirculation to participate in combustion during the working process of the engine, and its role is to reduce NOx emissions. Therefore, the exhaust gas can absorb part of the heat generated by combustion and take it out of the cylinder, and has a certain dilution effect on the mixture, so it reduces the maximum temperature and oxygen content of the engine combustion, thereby reducing the amount of NOx compounds generated.

In order to ensure that the amount of exhaust gas recirculation does not have an excessive impact on engine performance, modern electronically controlled engines also adopt a closed-loop control strategy for exhaust gas recirculation, and set the EGR valve position sensor at the exhaust gas recirculation valve to perform closed-loop modified feedback control on the actual amount of exhaust gas recirculation.