Abstract: A turbocharged diesel engine was altered to a duel fuel engine with intake pre-mixed methanol. Heat release rate calculation program of duel fuel engine based on cylinder pressure was written by Matlab. And test was conducted to study the duel fuel engine. The results show that while the methanol mixing ratio increases, ignition delay period of mixing fuel, the ratio of pre-mixed combustion and the peak of heat release rate increase, but the combustion duration decreases at all loads of low speed and middle and low loads of high speed. At high load of high speed, the timing of combustion is advanced significantly and the heat release rate curve shows multiple peaks when the methanol mixing ratio is high. The heat release time can be delayed; the peak of heat release rate and the maximum rate of pressure rise can be decreased by delaying fuel injection advance angle.

Key words: vehicle engineering, diesel engine, methanol, heat release rate, combustion characteristics

摘要： 对一台涡轮增压柴油机进行了改造，实现了柴油机进气预混甲醇双燃料燃烧。利用MATLAB软件编写了基于实测气缸压力的双燃料发动机放热规律计算程序，并对柴油机进气预混甲醇进行了试验研究。结果表明：在低转速全负荷和高转速中低负荷时，随着甲醇掺烧比的增加，柴油滞燃期延长，预混燃烧比例增大，放热率峰值增高，燃烧持续期缩短；在高转速大负荷时，较大的甲醇掺烧比会造成放热始点的大幅提前，放热率呈现多个峰值，出现了压力波动；适当推迟供油可以推迟放热始点并降低放热率峰值和最大压力升高率。

关键词: 车辆工程, 柴油机, 甲醇, 放热规律, 燃烧特性