Based on the strengths of polyoxymethylene dimethyl ethers (PODEn), F-T diesel and methanol, improving the energy conversion efficiency, an experiment was undertaken on modified CY25 diesel engine to study the effects of different methanol mass proportion on combustion characteristics with methanol/PODEn, methanol/F-T diesel premixed charge induced ignition mode. The results showed that with increasing methanol mass proportion, brake specific fuel consumption of methanol/PODEn combustion mode was increased and the effective thermal efficiency was decreased;but methanol/F-T diesel combustion mode is in the opposite trend when the methanol mass proportion is less than 60%. With increasing methanol mass proportion the combustion phase delay. In the maximum pressure and the maximum rate of instantaneous, the biggest ascending range of methanol/PODEn combustion mode reach 9.5%and 142% compared with original machine. And the biggest ascending range of methanol/F-T diesel combustion mode reach 4.24%and 99.7%.%针对甲醇、聚甲氧基二甲醚和F-T柴油的各自优势,为提高能量转化效率,在改造后的CY25防爆柴油机上研究甲醇质量比对甲醇/聚甲氧基二甲醚、甲醇/F-T柴油预混合引燃模式燃烧特性的影响.研究结果表明:随着甲醇质量比的增加,甲醇/聚甲氧基二甲醚燃烧模式的比油耗增大,有效热效率降低;在甲醇质量比小于60%时,随着甲醇质量比的增加,甲醇/F-T柴油燃烧模式的比油耗减少,有效热效率升高;随着甲醇质量比的增加,两种预混合引燃模式的燃烧相位均后移,与单燃料原机燃烧模式相比,甲醇/聚甲氧基二甲醚燃烧模式下的缸内压力峰值和瞬时放热率峰值的最大升幅分别为9.5%和142%,甲醇/F-T柴油燃烧模式下的缸内压力峰值和瞬时放热率峰值的最大升幅分别4.24%和99.7%.
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