喷射正时和喷油持续期对正丁醇-正辛醇双燃料发动机性能的影响

Effects of Start of Injection Timing and Injection Duration on the Performance of a N-butanol and N-octanol Dual-fuel Engine

将正丁醇、正辛醇分别作为预混合直喷燃料应用于双燃料发动机中,并利用KIVA4-CHEMKIN程序研究喷射正时和喷油持续期对正丁醇-正辛醇双燃料发动机燃烧及排放特性的影响。结果表明:喷射正时从5°提前到-10°时,可以提高发动机的缸内平均压力、热释放率(heat re⁃lease rate,HRR)峰值和平均指示压力(indicated mean effective pressure,IMEP),减少CO排放量,但会使最大压力升高率和NOx排放量增加。当喷射正时进一步提前到-15°时,会导致机械损失增加,IMEP下降。延长喷油持续期可以降低缸内平均压力、HRR峰值、最大压力升高率和NOx排放量,提高IMEP,但会使CO排放量先减少后增加。

N-butanol and n-octanol were used as premixed and direct injection fuels respectively in a dual-fuel engine.The effects of start of injection(SOI)timing,and injection duration on the combustion and emission characteristics of n-butanol and n-octanol dual-fuel engines were investigated with KIVA4-CHEMKIN code.The results show that when the SOI timing is advanced from 5°to-10°,the in-cylinder average pressure,peak heat release rate(HRR),and the indicated mean effective pressure(IMEP)of the engine is increased,and the CO emission is reduced,however the maximum pressure rise rate(MPRR)and NOx emission become higher.When the SOI timing is further advanced to-15°,the IMEP decreases due to the increased mechanical loss.Prolonging the injection duration could reduce the in-cylinder average pressure,peak HRR,MPRR and NOx emission in the cylinder,and improve IMEP.However,the CO emission decreases first and then increases.