EGR(国外英文资料).doc

EGR(国外英文资料) In order to adapt to the euro two standard, produced a lot of new devices, crankcase ventilation and exhaust gas recirculation is one, is the second. Exhaust gas recirculation mainly in order to reduce the content of nitrogen oxides in the exhaust gas of the crankcase ventilation in order to reduce oil carbon oxide content directly discharged into the atmosphere (also can reduce oil deterioration speed, balance the inside pressure and so on). What is the automobile exhaust gas recirculation system: Exhaust gas recirculation (EGR) system is used to reduce the emissions of nitrogen oxide (NOX) output. The nitrogen and oxygen chemical reaction will occur only at high temperature and high pressure to meet the above conditions of the engine combustion chamber temperature and pressure, especially in force during acceleration. When the engine is running in the load, the EGR valve is open, the small amount of exhaust gas into the intake manifold, and mix with combustible gas into the combustion chamber. Dongfeng Special vehicle chassis for example, Cummins EGR technology and Yuchai EGR technology has been widely applied in various types. The principle of application of EGR technology: NOX is generated in high temperature conditions, the inhibition of NOX formation, thereby reducing the content of NOX in the exhaust gas. However, excessive exhaust gas recirculation in the fire, and will affect the performance of the mixed gas, thus affecting the power of the engine, especially in engine idle, low speed, low load and cooler, the recirculated exhaust gas will significantly affect the engine performance. So, when the engine is at idle speed, low speed, small load and cooler, ECU does not participate in the control of exhaust gas recirculation, avoid the engine performance is affected; when the engine speed, and more than a certain load reaches a certain temperature, the ECU control part in exhaust gas recirculation, and the amount of exhaust gas recirculation in va