废乞再循环系统EGR解析.doc

废乞再循环系统EGR解析(EGR) engine control computer ECU according to engine speed, load (solar term door opening), temperature, gas flow rate, the exhaust temperature control electromagnetic valve timely open, intake manifold vacuum degree through the electromagnetic valve into the EGR valve vacuum membrane chamber, pull rod EGR diaphragm valve is opened, a small part of the exhaust gas in the EGR valve into the intake system, and the mixture into the cylinder combustion in after. A small part of the exhaust gas into the cylinder to participate in mixed gas combustion, reducing the temperature in the cylinder combustion, because NOX is generated in high temperature conditions, the inhibition of the generation of NOX, thereby reducing the content of NOX in the exhaust gas. However, excessive exhaust gas recirculation, participation, fire performance will affect the mixture, thus affecting the engine power, especially in the engine idle, low speed, small load and cooler, exhaust gas recirculation will significantly affect the engine performance. So, when the engine is in the idle, low speed, small load and cooler, exhaust gas recirculation ECU control does not participate in, avoid engine performance affected; when the engine over speed, and a certain load reaches a certain temperature, the ECU control part of exhaust gas recirculation less participation, and the amount of exhaust gas recirculation, participation and according to different engine speed, load, temperature and exhaust gas temperature is different, in order to achieve the lowest NOX in exhaust gas.(废气再循环)发动机控制电脑即ECU根据发动机的转速、负荷(节气门开度)、温度、进气流量、排气温度控制电磁阀适时地打开，进气管真空度经电磁阀进入EGR阀真空膜室，膜片拉杆将EGR阀门打开，排气中的少部分废气经EGR阀进入进气系统，与混合气混合后进入气缸参与燃烧。少部分废气进入气缸参与混合气的燃烧，降低了燃烧时气缸中的温度，因NOX是在高温富氧的条件下生成的，故抑制了NOX的生成，从而降低了废气中的NOX的含量。但是，过度的废气参与再循环，将会影响混合气的着火、性能，从而影响发动机的动力性，特别是在发动机怠速、低速、小负荷及冷机时，再循环的废气会明显地影响发动机性能。所以，当发动机在怠速、低速、小负荷及冷机时，ECU控制废气不参与再循环，避免