利用EGR控制甲醇发动机负荷

Load Control of a Methanol Engine by Using EGR

将一台2,L柴油机改装成点火式甲醇发动机,在该发动机上做了仅利用EGR(废气再循环)控制负荷的试验研究.试验时节气门全开,仅用废气和甲醇喷射量来调节负荷.试验中选择了多个点火提前角,寻找了每个点火提前角下的爆震对应的最小EGR率和转矩波动对应的最大EGR率,以及利用EGR可控的负荷范围.结果显示,在18,°CA BTDC点火时最大转矩达到153.4,N.m,在39,°CA BTDC点火时最小转矩达到55.5,N.m;点火提前角增大,最小EGR率逐渐增大,最大EGR率先增大后减小;点火提前角增大,最大转矩逐渐降低,最小转矩先增大后减小,且中间有波动;通过油耗分析,发现功率在14,kW以上,可以通过调整点火提前角来降低燃料消耗率,而功率小于14,kW之后通过调整点火提前角降低燃料消耗率不明显.

A 2 L diesel engine was modified into a spark ignition methanol engine, and the experiment on load control by using EGR was done on the engine. Throttle was full open in the experiment, and only exhaust gas and methanol quantity were used to adjust engine load. Several ignition timings were chosen in the research, and the minimum EGR rate corresponding to knock, the maximum EGR rate corresponding to torque fluctuation and the load range controlled by using EGR were found. The results show that the maximum torque reaches 153.4 N · m at the ignition timing of 18 ° CA BTDC, and the minimum torque reaches 55.5 N · m at the ignition timing of 39 ° CA BTDC. When ignition timing is advanced, the minimum EGR rate increases, while the maximum EGR rate first increases and then decreases; when ignition timing is advanced, the maximum torque decreases, while the minimum torque first increases and then decreases and some fluctuations appear. According to the analysis of fuel consumption, when power is higher than 14 kW, fuel consumption can be reduced by adjusting ignition timing, but when power is lower than 14 kW, fuel consumption cannot be effectively reduced by adjusting ignition timing.