可变涡流对稀燃二次喷油火花点燃式发动机性能影响的研究

主要研究了火花点燃式发动机采用二次喷油技术实现稀薄燃烧时,可变涡流对燃油经济性的影响情况。研究结果表明,在负荷和涡流比较大时,采用较小的二次喷油比例可获得较好的燃油经济性。而在缸内不存在涡流运动时,则须采用较大的二次喷油比例才能获得较好的燃油经济性。在缸内气体存在一定强度的涡流运动时,发动机的比油耗随二次喷油正时的变化呈波动状变化;当涡流比为0时,喷油正时对发动机油耗率的影响则与有涡流运动存在时的情况明显不同。这说明涡流运动对二次喷油在缸内的分布存在明显的影响。

A Study on the Effect of Variable Swirl on Performance of a Lean Burn SI Engine with TEFI

The effect of variable swirl on the fuel consumption of SI engine when TEFI (Twice Electronic Fuel Injection) was adopted to lean burn combustion was studied. The results indicated that when there is swirl motion in the cylinder, less second injection leads to lower fuel consumption; when there is no swirl motion in the cylinder, more second injection leads to lower fuel consumption. When there is swirl motion in the cylinder, the relation between the fuel consumption and second fuel injection timing is sine or cosine; when the swirl ratio is zero, the relation between the fuel consumption and second fuel injection timing is obviously different from the former one. This demonstrated that swirl motion has effect on the distribution of the fuel by second injection in the cylinder.