LPG/柴油双燃料发动机压缩比优化研究

采用燃料复合供给方式 ,在单缸直喷式柴油机上进行了LPG/柴油双燃料发动机压缩比的优化试验研究 ,对比分析了使用纯柴油和LPG/柴油双燃料的燃烧特性 ,着重研究分析了双燃料发动机在不同压缩比下的最高燃烧压力、最大压力升高率、压力循环波动及燃烧放热率 ,并以此为依据优选了双燃料发动机的压缩比。试验结果表明 :降低压缩比后 ,双燃料发动机的最高燃烧压力及最大压力升高率均有较大降低 ,同时压力循环波动变小 ,但滞燃期、燃烧持续期都会有所增加。经过优化 ,压缩比确定为 14.5时 ,ZH110 5W柴油机改燃LPG/柴油双燃料后在高负荷工况下无严重爆震现象 ,压力循环波动较小 ,且经济性较好 ,热效率损失不大

Study on the Compression Ratio Optimization of a LPG-Diesel Dual Fuel Engine

The investigation on compression ratio optimization of a LPG-diesel dual fuel single cylinder direct injection engine has been carried by using the compound fuel supply system. After comparing combustion characteristics of diesel fuel and LPG-diesel dual fuel, the maximum combustion pressure, maximum rate of pressure rise, cyclic pressure variation and heat release rate curve under different compressing ratios of the engine have been emphatically analyed. According to these results, the optimum compression ratio of dual fuel engine is selected. The experimental results show that the maximum combustion pressure, maximum pressure rise ratio as well as the cyclic variation of the engine decrease greatly when the engine compression ratio decreases, but the ignition delay period and combustion duration will increase. After Optimization, when the compression ratio of the LPG-diesel fuel engine is 14.5, for the engine ZH1105W under high load condition there is no serious deflagration, the cyclic pressure variation and losses of thermal efficiency decreases, the economy becomes better.