温度对增压二甲醚发动机性能的影响

Effects of Temperature on Performance Characteristics of a Turbocharged DME Engine

以一台增压二甲醚发动机为研究对象,研究进气温度和燃料温度对二甲醚发动机性能的影响。试验结果表明,进气温度升高,燃烧滞燃期缩短,放热率曲线往前移,预混合燃烧的峰值降低,预混合燃烧在整个燃烧过程中所占比例减小;进气温度升高会导致发动机油耗率上升,排温升高,NOx排放增加。二甲醚燃料温度的影响比进气温度升高,燃料温度增加会导致发动机功率下降。额定工况点下,当燃料温度由28℃升高到40℃时,发动机的功率由192.1 k W下降到168 k W,下降12.0%。二甲醚温度每升高1℃,二甲醚发动机功率平均下降1.0%。

The effects of temperature on performance characteristics of a turbocharged DME engine were investigated.The results showed that performance characteristics had been greatly affected by intake temperature and DME fuel temperature.With the increasing of intake temperature,ignition delay period would be shorten,the ignition starting point would be shifted to early,the peak of pre-mixed combustion would be reduced,which resulting in lower proportion of pre-mixed combustion in whole combustion duration.It was also found that BSFC,the exhaust temperature and NOxemission would be greatly increased with the increasing of intake temperature.The effects of DME＇s temperature on performance was larger than that of intake temperature,the output power of DME engine would be reduced with DME temperature.At the rated engine speed,when the DME temperature of fuel pump inlet was increased form 28 ℃ to 40 ℃,132.2 k W to 121.6 k W,the output power of DME engine would be reduced from 192.1 k W to 168 k W,which reduced by 12% at the engine speed of 2 200 r / min.It means the output power would be reduced by 1% as 1 ℃ temperature increasing at the operating point of rated power.