过量空气系数和点火正时对M100甲醇发动机性能影响研究

将一台4气门汽油机改装为燃用M100甲醇发动机，测量了甲醇发动机的动力性、经济性参数，研究了M100甲醇发动机性能随过量空气系数、点火提前角的变化规律。结果表明：转速为2 500 r/min、 部分负荷工况时，当过量空气系数一定，随点火提前角的增加，甲醇发动机的转矩增大，当量燃料消耗率下降，NO排放升高80%以上；相同工况时，当点火提前角一定，随过量空气系数的减小，发动机转矩增大，HC、CO排放明显增加。与燃用汽油相比，M100甲醇发动机外特性上的最大转矩增加约5.2%；在城市道路常用转速2 000 r/min，甲醇发动机按负荷特性运行，当量燃料消耗率低于原汽油机。

Effect of Excess Air Ratio and Ignition Timing on Performance of M100 Methanol Engine

The effects of excess air ratio and ignition timing on engine torque and break specific fuel consumption of a methanol engine transformed from a gasoline engine are studied, and the performance of M100 methanol engine is experimentally investigated. Results show that the engine torque increases with the increase in advanced ignition angle for a specified excess air ratio at 2 500 r/min, and the NO emission is increased by 80% when the fuel consumption decreases. When the excess air ratio decreases at a specified ignition time，the engine torque increases, and HC and CO emissions are significantly increased. The maximum torque is increased by 5.2% higher than that of original gasoline engine, and the brake specific fuel consumption is lower at speed of 2 000 r/min.