绝佳的英文柴油机培训资料

《绝佳的英文柴油机培训资料》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、FourstrokecycletheoryIntakestrokePistonmovingdownIntakevalveopenExhaustvalveclosedCopyright2003GaryLewis-DaveCapitoloFourstrokecycletheoryCompressionstrokePistonmovingupIntakevalveclosedExhaustvalveclosedFourstrokecycletheoryPowerstrokePistonmovingdownIntakevalveclosedExhaustvalveclosedFourstrok

2、ecycletheoryExhauststrokePistonmovingupIntakevalveclosedExhaustvalveopenFourstrokecycletheoryEachstroketakes180°ofcrankshaftrotationtocompleteAllcylindersfirein720°ofcrankshaftrotation720dividedbynumberofcylinders=firingintervalOddfireV-6engine(90°blockwith120°rodjournals)FourstrokedieseltheoryC

3、ompressionignitionDieselfuellowvolatilityHighcompressionratiosproducetheheatnecessaryPre-chamberforvaporizationRotaryenginetheoryPistondwelltimePistontravelisataminimum...TDCandBDCCrankmoveshorizontallyPistonvelocityMaximumwhenrodis90°tocrankAccelerationMaximum30°earlierBestVEisobtainedbysynchro

4、nizingvalveopeningwithpistonspeedsOtherenginecyclesOverlapBothvalvesareopenEndofexhaust&startofintakeLowpressureinexhaustportBlowdownExhaustvalveopensbeforeBDCTohelpevacuatecylinderbeforepistonreversesPumpinglossesatendofexhauststrokeValveeventsIntakevalveopeningBTDCLowpressureincylinderIntakeva

5、lveclosingABDCCylinderpressureiseffectedbytimingExhaustvalveopeningBBDCResidualpressurehelpsblowdownExhaustvalveclosingATDCLowpressureinexhaustportdrawsairinEffectsonvalvetimingIntakevalveopeningLate–ReducedVEEarly–DilutionofintakewithexhaustIntakevalveclosingLate–ReducescylinderpressureEarly–In

6、creasescylinderpressureExhaustvalveopeningLate–PumpinglossesEarly–PowerreductionExhaustvalveclosingLate–ReducesvacuumEarly–ReducesVECombustionSparkignitionMaximumcylinderpressure15°ATDCTumbleandswirlMotionreducesmisfiresExcessmotioninhibitsflowAFR14.7:1atpartthrottle,12.5:1underloadCompressionig

7、nition18:1directinjection23:1pre-chambersforbetterstartingCrankingheatsairto600°FCompressionheatsareto800-1200°FDieselfuelsCetanevolatilitynumbers50-55Highercetane#1fuelforcoldweatherLowercetane#2fuelforwarmweatherParaffinse