在单缸柴油机上通过测量得到了燃用不同掺混比甲醇生物柴油时的燃烧示功图，对不同柴油机工况下甲醇生物柴油燃烧的循环变动进行了研究，分析了最大压力升高率循环变动系数（COV(dp/dφ)max）、平均指示压力循环变动系数（COVpmi）、最高燃烧压力的变动系数（COVpmax）、最高燃烧压力对应曲轴转角的标准偏差（SDφpmax）等循环变动的评价参数。研究结果表明：工况一定时，随着甲醇掺混比增加，COV(dp/dφ)max，COVpmi等循环变动系数均有所增大；与生物柴油相比，甲醇掺混比为10%和20%时循环变动系数变化较小，当甲醇掺混比为30%时，COV(dp/dφ)max增加了6.2%，COVpmi增加了24.2%，COVφpmax增加了8.4%；当甲醇掺混比不变时，随着转速的增加，COV(dp/dφ)max降低，COVpmi以及COVpmax先降低后增高；负荷增加时，各压力参数的循环变动系数均降低，SDφpmax略微上升。

The combustion indicator diagrams were measured on a single cylinder diesel engine fueled with different blended fuels of diesel and methanol. The combustion cyclic variation of blended fuel was studied under different conditions, which analyzed the evaluation parameters of cyclic variation such as the maximum pressure rise rate coefficient COV(dp/dφ)max the mean indicated pressure coefficient COVpmi, the maximum combustion pressure coefficient COVpmax and the standard error of its corresponding crank angle SDφpmax . The results show that COV(dp/dφ)max and COVpmi increase with the increase of methanol mixing ratio.Compared with biodiesel, the changes of cyclic variation coefficients are smaller when the mixing ratios are 10% and 20%.When the mixing ratio of methanol increases to 30%, the COV(dp/dφ)max increases by 6.2%, COVpmi increases by 24.2%, and  COVpmax increases by 8.4%. For the constant mixing ratio, COV(dp/dφ)max decreases and COVpmi and COVpmax first decrease and then increase with the increase of speed. With the increase of load, the cyclic variation coefficients of all pressure parameters decrease, but the corresponding standard error of maximum combustion pressure slightly increases.