不同点火时刻下天然气掺氢缸内直喷发动机燃烧与排放特性.PDFVIP

第24卷(2006)第5期 内 燃 机 学 报 Vol.24(2006)No.5 TransactionsofCSICE 文章编号:1000-0909(2006)05-0394-08 24-066 不同点火时刻下天然气掺氢缸内直喷发动机燃烧 与排放特性· 王金华，黄佐华，刘 兵，曾 科，余金荣，蒋德明 (西安交通大学动力工程多相流国家重点实验室，陕西西安710049) 摘要:在缸内直喷火花点火发动机上开展了天然气掺混0%一18%氢气的混合燃料不同点火时刻下的试验研 究。结果表明:对于给定的喷射时刻和喷射持续期，点火时刻对发动机性能、燃烧和排放有较大影响，喷射结 束时刻与点火时刻的间隔对直喷天然气发动机极为重要，喷射结束时刻与点火时刻的间隔缩短时，混合气分 层程度高，燃烧速率快，热效率高。最大放热率等燃烧特征参数随点火时刻的提前而增加。HC排放随点火 时刻的提前而下降，CO:和NO二排放随点火时刻的提前而增加，NO二排放的增加在大点火提前角下更明显。 掺氢可降低HC排放，对CO和CO:排放影响不大。掺氢量大于10%时可提高天然气发动机热效率。 关键词:天然气;氢气;点火时刻;燃烧;排放;缸内直喷 中图分类号:TK421.2 文献标志码:A CombustionandEmissionCharacteristicsofaDirect-InjectionEngineFueled withNaturalGas/HydrogenBlendsunderVariousIgnitionTimings WANGJin-hua，M ANGZuo-hua,LIUBing,ZENGKe,YUJin-rong，JIANGDe-ming (StateKeyLaboratoryofMultiphaseFlowinPowerEngineering,XianJiaotongUniversity,Xian710049，China) Abstract;Inthispaper,anexperimentalstudyoncombustionandemissioncharacteristicsinadirect-in- jectionspark-ignitedenginefueledwithCNG/hydrogenblendsundervariousignitiontimingswasinvesti- gated.Theresultsshowthattheignitiontiminghassignificantinfluenceonengineperformance，combus- tionandemissions.Theintervalbetweentheendoffuelinjectionandignitiontimingisaveryimportant parameterofthedirect-injectionnaturalgasengine.Theturbulenceflowincombustionchambergenerated bythefueljetmaintainshighandrelativestrongmixturestratificationispresentedwhendecreasingthein- tervalbetweentheendofinjectionandtheignitiontiming,givingfastburningrateandhighthermaleffi- ciency.Themaximumrateofheatreleaseincreasewiththeadvanceofignitiontiminganditgiveslittle variationwithhydrogenadditionunderthesameignitiontiming.Thisindi