四气门汽油机分层EGR的试验研究

针对可以产生较强滚流运动的1.6 L四气门产品汽油机,设计了一套独特的分层废气再循环(EGR)装置。通过废气导入管将废气引到进气阀处,利用缸内气体滚流运动,实现废气与新鲜可燃混合气分层。在发动机台架上通过试验详细地研究该分层EGR装置对汽油机性能和燃烧的影响。试验结果表明,采用该装置后,相比于传统的EGR方式,EGR 率有所增加,在大量降低NOx排放同时,经济性有所改善, CO和HC排放有所降低,燃烧效率提高,但点火时刻应适当提前。

STUDY ON STRATIFIED EGR FOR SI ENGINE WITH 4-VALVE

A special device to produce stratified exhaust gas recycled (EGR) was designed on one SI engine with 4-valve and with a chamber which could give intensive tumble in cylinder. The device had a pilot to introduce exhaust gas into cylinder by one side of intake port. Thus the exhaust gas entered into cylinder with the tumble to divide the two parts of mixture. One part was composed of exhaust gas and fresh charge, and the other part was only made of fresh charge. The engine was tested on bench. The testing results showed that compared with the conventional EGR system, the stratified one had higher EGR rate, better fuel economy and burning efficiency, as well as lower CO and HC emissions with reduction of NOx emission. However, the new EGR system should be ignited in advance.