气门相位对高膨胀比发动机性能影响的研究

在1台几何压缩比为12的双独立可变凸轮相位汽油机上,在转速1 500~5 500 r/min、全负荷工况下进行了不同进排气相位对发动机输出扭矩、燃油消耗率、爆震倾向影响的试验研究,分析了不同转速下进排气相位优化的规律以及对发动机性能的影响。试验结果表明,采用可变相位技术后,低速时扭矩提高超过8%,中高速时功率增长达10%~14.8%,转速在4 500 r/min以下燃油消耗率平均降低5%,在2 000 r/min时最低燃油消耗率达到250 g/(kW.h)。

The Influence of Cam Phasing on Engine Performance with High Expansion Ratio

On a dual-independent variable valve timing gasoline engine with a compression ratio of 12,the influences of different intake and exhaust phases on output torque,specific fuel consumption and knock tendency under full loads at the speed range from 1 500 r/min to 5 500 r/min were researched.The cam phase optimization and its influence on engine performance under different speeds were analyzed.The results show that the variable valve timing system can improve the engine performance effectively.At low speed,the output torque increases by 8%.At middle and high speed,the power increases by 10%-14.8%.At the speed of 4 500 r/min or lower,the specific fuel consumption decreases by 5% in average.At the speed of 2 000 r/min,the minimal specific fuel consumption reaches to 250 g/(kW·h).