中文摘要：

在一台重载柴油机上，对柴油／甲醇二元燃料燃烧不同甲醇替代率下发动机的进气成分、气体排放特性和燃料效率进行了研究。结果表明，随着甲醇替代率的增加，发动机进气流量、NOx排放和折合当量燃油消耗率依次减小，而发动机过量空气系数、HC和CO排放以及有效热效率持续增加。在甲醇替代率达到30％时，NOx排放和燃料效率同时取得最优效果；NOx平均下降了34．51％，折合当量燃油消耗率最低仅为181．85g／（kW．h），整体平均下降了6．03％，有效热效率平均提高了6．40％。

英文摘要：

Diesel/methanol dual fuel combustion was realized on a heavy duty diesel engine, and the characteristics of inlet gas composition, gas emissions and fuel efficiency were studied at different methanol substitution ratios. Results show that air input, NOx emission and brake specific fuel consumption decrease with the increase of methanol substitution ratio, while excess air coefficient, HC and CO emission and brake thermal efficiency increase continuously. NOx emission and fuel efficiency gain the best at 30% of methanol substitution ratio. In this case, the NOx emission decrease by 34.51% averagely and the lowest brake specific equivalent fuel consumption is only 181.85g/（kW.h） with a mean decrease of 6.03%, the brake thermal efficiency increase by 6.40% on average.