降低火花点火发动机未燃碳氢方法的研究

INVESTIOATION ON REDUCTION METHOD OF UNBURNED HYDROCARBONS IN SPARK IGNITION ENGINES)

开展了不同顶岸间隙时火花点火发动机未燃碳氢排放的实验研究，并对顶岸间隙宽度对发动机动力性和经济性的影响进行了分析，认为最佳的顶岸间隙宽度应为１．３倍双壁激冷厚度，在此条件下火焰将传播进顶岸间隙内，烧掉其内积蓄的未燃碳氢量，这样既能达到有效降低发动机排气未燃碳氢（排气碳氢下降３５％～５０％），又不会对发动机的动力性和经济性产生较大影响（功率下降０．５％～１．５％，燃料消耗率增加１％～３％）。

The experimental study on unburned hydrocarbon emissions with different top-landcrevices was performed in spark ignition engine,and the influences of top-land crevice widthon engine power output and fuel economy were analyzed.It is concluded that the optimum en-gine top-land crevice width should be 1.3 times of the two-wall quenching distance 0. 32mm,in this case flame can get into the crevice and burns out the accumulated unburned hydrocar-bons in it,thus the engine exhaust hydrocarbons can be greatly reduced(35%～50%reduc-tion in hydrocarbons)and has less penalty on engine power output and fuel economy(0.5%～1.5%loss in power output and 1%～3%loss in fuel consumption).