汽油机NO_x的形成及控制

FORMATION AND CONTROLS OF NO_x EMISSIONS OF GASOLINE ENGINE

对NO的生成机理进行了分析 对以下因素———燃空当量比、燃烧产物高温区停留时间、点火提前角、负荷、转速及冷却水温与混合气温度对NO生成的影响进行了详细讨论 最后提出了降低NOx 排放的各种控制措施 ,其中包括适当推迟点火提前角、降低冷却水温、通过进气喷水增加进气湿度、降低压缩比、排气再循环以及在机外加催化器

The forming mechanism of NO is analyzed. The following factors--excess air ratio, retention period of the combustion products in the high temperature area, ignition advance angle, load, speed and temperature of the cooling water and the gas mixture, which have great effect on NO x , are discussed in detail. Measures are provided to reduce NO x emissions, such as delaying the ignition advance angle properly, decreasing the temperature of the cooling water, increasing the intake humidity by the intake water spray, reducing the compression ratio, adopting EGR and mounting catalytic converter outside the engine. In addition, putting absorbent materials in the exhaust system and adopting intake valve total variable cam adjusting system can also lower NO x emissions greatly.