排气凸轮缓冲段型线对发动机动力性、经济性的影响

The Influence of the Shape of the Buffer Section of the Exhaust Cam on the Power and Economy of the Engine

结合某四缸自吸、电控共轨、带VVT顶置凸轮轴汽油发动机,通过调整排气凸轮轴缓冲段型线,保持ECU数据不变,通过理论计算与台架试验,对比2种状态的凸轮轴对发动机扭矩、油耗、排温的影响。结果显示:适当调整排气凸轮缓冲段型线,增大气门重叠角,对发动机动力性无影响;油耗有所降低;也存在部分工况点油耗增大的情况;发动机在高速、中大负荷排温会有所升高。

Combined with a four cylinder self-spriming,electronically controlled common rail,gasoline engine with VVT overhead camshaft,the influence of camshaft on engine torque,fuel consumption and exhaust temperature is compared to two kinds of state of the camshaft by adjusting the buffer section of exhaust camshaft and keeping ECU data unchanged through theoretical calculation and bench test.The results show that:adjusting the profile of the buffer section of the exhaust cam properly and increasing the valve overlap angle will have no effect on the engine power performance;the fuel consumption will be reduced,but also the fuel consumption will be increased at some operating points;the engine exhaust temperature will be increased at high speed,medium and large load.