喷射参数对二甲醚PPCCI发动机燃烧与排放特性的影响.pdf

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1、第38卷第5期内燃机工程V01．38No．52017年10月ChineseInternalCombustionEngineEngineeringOctober．2017文章编号：1000--0925(2017)05一0022一06380096喷射参数对二甲醚PPCCI发动机燃烧与排放特性的影响杨武林，王春海，黄震(上海交通大学动力机械与工程教育部重点实验室，上海200240)InfluencesofInjectionParametersonCombustionandEmissionCharacteristicsinaDimethylEtherPPCCIEngineY

2、ANGWulin，WANGChunhai，HUANGZhen(MinistryKeyLaboratoryofPowerMachineryandEngineering，ShanghaiJiaoTongUniversity，Shanghai200240，China)Abstract：Theeffectsofpilotinjectiontiming，pilotinjectionquantity，injectionpressureandmaininjectiontimingonthepartialpremixedchargecompressionignition(PPCCI

3、)combustionandemissionsofasixcylinders，electronicallycontrolledcommonraildimethylether(DME)enginewereinvestigated．Resultsshowthat，withtheadvanceofthepilotinjectiontiming，thepeakcylinderpressureisreduced，andthecombustionheatreleaseischangedfromthetwo—stagemodetothethree—stagemodeofPPCCI

4、；inaddition，NO，emissionisreduced，andHCandCOemissionsareincreased．Withtheincreaseofpilotinjectionquantity，thepeakcylinderpressureandthereactionratesofcoolflameandthermalflameofthePCCIareincreased，HCandC0emissionsarealsoincreased，whileNO：emissionisdecreased．Withthedecreaseofinjectionpres

5、sure，thepeakvalueofheatreleaserateofthePCCIisincreasedandthestartofthemaininjectiondiffusioncombustionisdelayed，thepeakheatreleaserateofthemaininjectiondiffusionissignificantlyreduced；furthermore，N0。emissionissignificantlydecreasedwhileHCandCOemissionsareincreaseddramatically．Withthede

6、layofthemaininjectiontiming，thereislittlechangeinthePCCI，thestartofthemaininjectiondiffusioncombustionisdelayedsignificantly，thepeakpressureandthepeakheatreleaseratearedecreased；moreover，NO。emissionissignificantlydecreasedwhileHCandCOemissionsarejncreased．摘要：在一台6缸增压电控共轨二甲醚发动机上进行试验，研究了预

7、喷时刻、预喷燃料量、喷射压力、主喷时刻等喷射参数对二甲醚部分预混合充量压缩燃烧(PPCCI)发动机燃烧与排放特性的影响。试验结果表明：随预喷时刻提前，缸内压力峰值降低，二甲醚发动机缸内燃烧由两阶段放热转变为PPCCI三阶段放热，氮氧化物(N0。)排放显著降低，HC和CO排放升高；随预喷射燃料量增加，缸内压力峰值及预混合燃烧的冷焰反应和热焰反应速率明显增大，No，排放逐渐降低，HC和Co排放显著升高；随喷射压力降低，预混合燃烧热焰反应速率增加，主喷扩散燃烧始点推迟，扩散燃烧放热率峰值和No。排放明显降低，HC和CO排放升高；随主喷时刻推迟，预喷预混合燃烧几乎没有变