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GENERALCOMMENTSOFAUTOMOBILEENGINEENGINEISTHESOURCEOFAUTOMOTIVESOFAR,AUTOMOTIVEENGINESAREALLPOWEREDBYHEATEXCEPTFORAFEWOFAUTOMOTIVESDRIVEDBYELECTRICITYMODERNAUTOMOTIVEENGINESARECALLEDINTERNALCOMBUSTIONENGINESBECAUSEFUELBURNSINSIDETHEENGINETHEENGINECONVERTSTHEBURNINGFUELSTHERMALENERGYTOMECHANICALENERGYBYCOOLINGSYSTEMSLIQUIDCOOLEDENGINESANDAIRCOOLEDENGINESAREBEINGUSEDLIQUIDCOOLEDENGINESARETHEMOSTCOMMONINTHEDIESELINDUSTRYBYFUELSYSTEMGASOLINEDIESELANDPROPANEFUELSYSTEMSARECURRENTLYUSEDINAWIDEVARIETYOFENGINESBYIGNITIONMETHODGASENGINESUSETHESPARKELECTRICALIGNITIONDIESELENGINESUSETHEHEATFROBDCTOTDCITVARIESWITHCYLINDERBORESIZE,LENGTHOFPISTONSTROKE,ANDNUMBSYSTEMINJECTIONTHECALORYOFDIESELENGINECOMEFROMTHEFUELEMBLAZEDBYTHECOMPRESSEDAIRTHEDIESELENGINECOMPRESSIONRATIONISMUCHBIGGERTHANTHEGASENGINEITSSUFFICIENTCALORYISFROMTHEFUELBURNEDBYTHEPRESSEDAIRBYVALVEARRANGEMENTFOURTYPESOFVALVEARRANGEMENTSHAVEBEENUSEDINGASOLINEANDDIESELENGINESOFTHEFOURTYPESL,T,F,ANDIHEADS,THEIHEADISCOMMONLYUSEDONDIESELENGINESBYCYLINDERARRANGEMENTENGINEBLOCKCONFIGURATIONORCYLINDERARRANGEMENTDEPENDSONCYLINDERBLOCKDESIGNCYLINDERSMAYBEARRANGEDINASTRAIGHTLINEONEBEHINDTHEOTHERTHEMOSTCOMMONINLINEDESIGNSARETHEFOURANDSIXCYLINDERENGINESTHEVTYPEOFCYLINDERARRANGEMENTUSESTWOBANKSOFCYLINDERSARRANGEDINA60TO90VDESIGNTHEMOSTCOMMONEXAMPLESARETHOSEWITHTWOBANKSOFTHREETOEIGHTCYLINDERSEACHTHEOPPOSEDENGINEUSESTWOBANKSOFCYLINDERSOPPOSITEEACHOTHERWITHTHECRANKSHAFTINBETWEENENGINECLASSIFICATIONACCORDINGTOTHEDIFFERENCESOFTHEPISTONMOVEMENT,THEPISTONINTENALCOMBUSITIONENGINEWILLBECLASSIFIEDRECIPROCATINGINTENALCOMBUSITIONENGINEANDROTARYPISTONINTENALCOMBUSITIONENGINETHENWEWILLINTRODUCEWORKINGPRINCIPLEDIAGRAMOFRECIPROCATINGINTERNALCOMBUSTIONENGINEEXCEPTFORTHEWANKELROTARY,ENGINE,ALLPRODUCTIONAUTOMOTIVEENGINESARETHERECIPROCATING,ORPISTON,DESIGNRECIPROCATINGMEANS“UPANDDOWN“OR“BACKANDFORTH“ITISTHISUPANDDOWNACTIONOFAPISTONINACYLINDERTHATGIVESTHERECIPROCATINGENGINEITSNAMEALMOSTALLENGINESOFTHISTYPEAREBUILTUPONACYLINDERBLOCK,ORENGINEBLOCKTHEBLOCKISANIRONORALUMINUMCASTINGTHATCONTAINSTHEENGINECYLINDERSTHETOPOFTHEBLOCKISCOVEREDWITHTHECYLINDERHEAD,WHICHFORMSTHECOMBUSTIONCHAMBERSTHEBOTTOMOFTHEBLOCKISCOVEREDWITHANOILPAN,OROILSUMPAMAJOREXCEPTIONTOTHISTYPEOFENGINEONSTRUCTIONISTHEAIRCOOLEDVOLKWAGENENGINEITISREPRESENTATIVEOFTHEHORIZONTALLYOPPOSEDAIRCOOLEDENGINESUSEDBYPORSCHE,CHEVROLETCORVAIR,ANDSOMEOTHERAUTOMOBILEMANUFACTURERSINYEARSPASTPOWERISPRODUCEDBYTHEINLINEMOTIONOFAPISTONINACYLINDERHOWEVER,THISLINEARMOTIONMUSTBECHANGEDTOROTATINGMOTIONTOTURNTHEWHEELSOFACARORTRUCKTHEPISTONISATTACHEDTOTHETOPOFACONNECTINGRODBYAPIN,CALLEDAPISTONPINORWRISTPINTHECONNECTINGRODTRANSMITSTHEUPANDDOWNMOTIONOFTHEPISTONTOTHECRANKSHAFT,WHICHCHANGESITTOROTATINGMOTIONTHECONNECTINGRODISMOUNTEDONTHECRANKSHAFTWITHLARGEBEARINGSCALLEDRODBEARINGSSIMILARBEARINGS,CALLEDMAINBEARINGS,AREUSEDTOMOUNTTHECRANKSHAFTINTHEBLOCKTHECRANKSHAFTCHANGESTHERECIPROCATINGMOTIONOFTHEPISTONSTOROTATINGMOTIONTHECOMBUSTIBLEMIXTUREOFGASOLINEANDAIRENTERSTHECYLINDERSTHROUGHVALVESAUTOMOTIVEENGINESUSEPOPPETVALVESTHEVALVESCANBEINTHECYLINDERHEADORINTHEBLOCKTHEOPENINGANDCLOSINGOFTHEVALVESISCONTROLLEDBYACAMSHAFTLOBESONTHECAMSHAFTPUSHTHEVALVESOPENASTHECAMSHAFTROTATESASPRINGCLOSESEACHVALVEWHENTHELOBEISNOTHOLDINGITOPENTHEMOSTCOMMONARRANGEMENTSOFENGINECYLINDERSANDVALVESAREDISCUSSEDLATERTHEBASICSINGLECYLINDERENGINECONSISTSOFACYLINDERENGINEBLOCK,AMOVABLEPISTONINSIDETHISCYLINDER,ACONNECTINGRODATTACHEDATTHETOPENDTOTHEPISTONANDATTHEBOTTOMTOTHEOFFSETPORTIONOFACRANKSHAFT,ACAMSHAFTTOOPERATETHETWOVALVESINTAKEANDEXHAUST,ANDACYLINDERHEADAFLYWHEELISATTACHEDTOONEENDOFTHECRANKSHAFTTHEOTHERENDOFTHECRANKSHAFTHASAGEARTODRIVETHECAMSHAFTGEARTHECAMSHAFTGEARISTWICEASLARGEASTHECRANKSHAFTGEARTHISDRIVESTHECAMSHAFTATHALFTHESPEEDOFTHECRANKSHAFTONFOURSTROKECYCLEENGINES,THECRANKSHAFTANDCAMSHAFTRUNATTHESAMESPEEDENERGYCONVERSIONTHEINTERNALCOMBUSTIONDIESELENGINEISADEVICEUSEDTOCONVERTTHECHEMICALENERGYOFTHEFUELINTOHEATENERGYANDTHENCONVERTTHISHEATENERGYINTOUSABLEMECHANICALENERGYTHISISACHIEVEDBYCOMBININGTHEAPPROPRIATEAMOUNTSOFAIRANDFUELANDBURNINGTHEMINANENCLOSEDCYLINDERATACONTROLLEDRATEAMOVABLEPISTONINTHECYLINDERISFORCEDDOWNBYTHEEXPANDINGGASESOFCOMBUSTIONTHEMOVABLEPISTONINCYLINDERISCONNECTEDTOTHETOPOFACONNECTINGRODTHEBOTTOMOFTHECONNECTEDRODISATTACHEDTOTHEOFFSETPORTIONISTRANSFERREDTOTHECRANKSHAFT,ASTHEPISTONISFORCEDDOWN,THISOFFSETPORTIONOFACRANKSHAFT,TOROTATETHERECIPROCATINGBACKANDFORTHORUPANDDOWNMOVEMENTOFTHEPISTONISCONVERTEDTOROTARYTURNINGMOTIONOFTHECRANKSHAFT,WHICHSUPPLIESTHEPOWERTODRIVETHEVEHICLEINGENERALANAVERAGEAIRFUELRATIOFORGOODCOMBUSTIONISABOUT15PARTSOFAIRTO1PARTOFFUELBYWEIGHTHOWEVER,THEDIESELENGINEALWAYSTAKESINAFULLCHARGEOFAIRSINCETHEREISNOTHROTTLEPLATEINMOSTSYSTEMS,BUTONLYASMALLPARTOFTHISAIRISUSEDATLOWORIDLEENGINESPEEDSAIRCONSISTSOFABOUT20PERCENTOXYGENWHILETHEREMAINING80PERCENTISMOSTLYNITROGENTHISMEANSTHAT,FOREVERYGALLONOFFUELBURNED,THEOXYGENIN9,000TO10,000GALLONSOFAIRISREQUIREDFOURSTROKECYCLEGASOLINEBYITSELFWILLNOTBURN,ITMUSTBEMIXEDWITHOXYGENAIRTHISBURNINGISCALLEDCOMBUSTIONANDISAWAYOFRELEASINGTHEENERGYSTOREDINTHEAIRFUELMIXTURETODOANYUSEFULWORKINANENGINE,THEAIRFUELMIXTUREMUSTBECOMPRESSEDANDBURNEDINASEALEDCHAMBERHERETHECOMBUSTIONENERGYCANWORKONTHEMOVABLEPISTONTOPRODUCEMECHANICALENERGYTHECOMBUSTIONCHAMBERMUSTBESEALEDASTIGHTLYASPOSSIBLEFOREFFICIENTENGINEOPERATIONANYLEAKAGEFROMTHECOMBUSTIONCHAMBERALLOWSPARTOFTHECOMBUSTIONENERGYTODISSIPATEWITHOUTADDINGTOTHEMECHANICALENERGYDEVELOPEDBYTHEPISTONMOVEMENTTHE4STROKEENGINEISALSOCALLEDTHEOTTOCYCLEENGINE,INHONOROFTHEGERMANENGINEER,DRNIKOLAUSOTTO,WHOFIRSTAPPLIEDTHEPRINCIPLEIN1876INTHE4STROKEENGINE,FOURSTROKESOFTHEPISTONINTHECYLINDERAREREQUIREDTOCOMPLETEONEFULLOPERATINGCYCLETWOSTROKESUPANDTWOSTROKESDOWNEACHSTROKEISNAMEDAFTERTHEACTIONITPERFORMSINTAKE,COMPRESSION,POWER,ANDEXHAUST1、INTAKESTROKEASTHEPISTONMOVESDOWN,THEVAPORIZED,MIXTUREOFFUELANDAIRENTERSTHECYLINDERPASTTHEOPENINTAKEVALVE2、COMPRESSIONSTROKETHEPISTONRETURNSUP,THEINTAKEVALVECLOSES,THEMIXTUREISCOMPRESSEDWITHINTHECOMBUSTIONCHAMBER,ANDIGNITEDBYASPARK3、POWERSTROKETHEEXPANDINGGASESOFCOMBUSTIONFORCETHEPISTONDOWNINTHECYLINDERTHEEXHAUSTVALVEOPENSNEARTHEBOTTOMOFTHESTROKE4、EXHAUSTSTROKETHEPISTONMOVESBACKUPWITHTHEEXHAUSTVALVEOPEN,ANDTHEBURNEDGASESAREPUSHEDOUTTOPREPAREFORTHENEXTINTAKESTROKETHEINTAKEVALVEUSUALLYOPENSJUSTBEFORETHETOPOFTHEEXHAUSTSTROKETHIS4STROKECYCLEISCONTINUOUSLYREPEATEDINEVERYCYLINDERASLONGASTHEENGINEREMAINSRUNNINGTWOSTROKECYCLETHETWOSTROKECYCLEDIESELENGINECOMPLETESALLFOUREVENTSINTAKE,COMPRESSION,POWER,ANDEXHAUSTINONEREVOLUTIONOFTHECRANKSHAFTORTWOSTROKESOFTHEPISTONASERIESOFPORTSOROPENINGSISARRANGEDAROUNDTHECYLINDERINSUCHAPOSITIONTHATTHEPORTSAREOPENWHENTHEPISTONISATTHEBOTTOMOFITSSTROKEABLOWERFORCESAIRINTOTHECYLINDERTHROUGHTHEOPENPORTSEXPELLINGALLREMAININGEXHAUSTGASESPASTTHEOPENEXHAUSTVALVESANDFILLINGTHECYLINDERWITHAIRTHISISCALLEDSCAVENGINGASTHEPISTONMOVESUP,THEEXHAUSTVALVESCLOSEANDTHEPISTONCOVERSTHEPORTSTHEAIRTRAPPEDABOVETHEPISTONISCOMPRESSEDTONCOVERSTHEPORTSTHEAIRTRAPPEDABOVETHEPISTONISCOMPRESSEDSINCETHEEXHAUSTVALVEISCLOSEDJUSTBEFORETHEPISTONREACHESTOPDEADCENTER,THEREQUIREDAMOUNTOFFUELISINJECTEDINTOTHECYLINDERTHEHEATGENERATEDBYCOMPRESSINGTHEAIRIGNITESTHEFUELALMOSTIMMEDIATELYCOMBUSTIONCONTINUESUNTILTHEFUELINJECTEDHASBEENBURNEDTHEPRESSURERESULTINGFROMCOMBUSTIONFORCESTHEPISTONDOWNWARDONTHEPOWERSTROKEWHENTHEPISTONISAPPROXIMATELYFALFWAYDOWN,THEEXHAUSTVALVESAREOPENED,ALLOWINGTHEEXHAUSTGASESTOESCAPEFURTHERDOWNWARDMOVEMENTUNCOVERSTHEINLETPORTS,CAUSINGFRESHAIRTOENTERTHECYLINDERANDEXPELTHEEXHAUSTGASESTHEENTIREPROCEDUREISTHENREPEATED,ASTHEENGINECONTINUESTORUNTHEDIFFERENCESOFTHETWOINTENALCOMBUSTIONENGINEITCOULDBEASSUMEDTHATATWOCYCLEENGINEWITHTHESAMENUMBEROFCYLINDERS,THESAMEDISPLACEMENT,COMPRESSIONRATIO,ANDSPEEDASAFOURCYCLEENGINEWOULDHAVETWICETHEPOWERSINCEITHASTWICEASMANYPOWERHOWEVER,THISISNOTTHECASE,SINCEBOTHTHEPOWERANDCOMPRESSIONSTROKESARESHORTENEDTOALLOWSCAVENGINGTOTAKEPLACETHETWOCYCLEENGINEALSOREQUIRESABLOWER,WHICHTAKESENGINEPOWERTODRIVEABOUT160DEGREESOUTOFEACH360DEGREESOFCRANKSHAFTROTATIONAREREQUIREDFOREXHAUSTGASEXPULSIONANDFRESHAIRINTAKESCAVENGINGINATWOCYCLEENGINEABOUT415DEGREESOFEACH720DEGREESOFCRANKSHAFTROTATIONINAFOURCYCLEENGINEAREREQUIREDFORINTAKEANDEXHAUSTTHESEFIGURESINDICATETHATABOUT445OFCRANKROTATIONISUSEDFORTHEPOWERPRODUCINGEVENTSINTHETWOCYCLEENGINE,WHILEABOUT59OFCRANKROTATIONISUSEDFORTHESEPURPOSESINTHEFOURCYCLEENGINEFRICTIONLOSSESARECONSEQUENTLYGREATERINTHEFOURCYCLEENGINEHEATLOSSES,HOWEVER,AREGREATERINTHETWOCYCLEENGINETHOUGHBOTHTHEEXHAUSTANDTHECOOLINGSYSTEMSINSPITEOFTHESEDIFFERENCES,BOTHENGINETYPESENJOYPROMINENTUSEWORLDWIDEENGINECONSTRUCTIONCYLINDERBLOCKTHECYLINDERBLOCKISCASTINONEPIECEUSUALLY,THISISTHELARGESTANDTHEMOSTCOMPLICATEDSINGLEPIECEOFMETALINTHEAUTOMOBILETHECYLINDERBLOCKISACOMPLICATEDCASTINGMADEOFGRAYIRONCASTIRONORALUMINUMITCONTAINSTHECYLINDERSANDTHEWATERJACKETSTHATSURROUNDTHEMTOMAKETHECYLINDERBLOCK,ASANDFORMCALLEDAMOLDISMADETHENMOLTENMETALISPOUREDINTOTHEMOLDWHENTHEMETALHASCOOLEDTHESANDMOLDISBROKENUPANDREMOVEDTHISLEAVESTHETOUGHCYLINDERBLOCKCASTINGTHECASTINGTHECASTINGISTHENCLEANEDANDMACHINEDTOMAKETHEFINISHEDBLOCKCYLINDERBLOCKSFORDIESELENGINESAREVERYSIMILARTOTHOSEFORSPARKIGNITIONENGINESTHEBASICDIFFERENCEISTHATTHEDIESELENGINECYLINDERBLOCKISHEAVIERANDSTRONGERTHISISBECAUSEOFTHEHIGHERPRESSURESDEVELOPEDINTHEDIESELENGINECYLINDERSSEVERALENGINESHAVEALUMINUMCYLINDERBLOCKSALUMINUMISRELATIVELYLIGHTMETAL,WEIGHINGMUCHLESSTHANCASTIRONALSO,ALUMINUMCONDUCTSHEATMORERAPIDLYTHANCASTSOFTTOUSEASCYLINDERWALLMATERIALITWEARSTOORAPIDLYTHEREFORE,ALUMINUMCYLINDERBLOCKSMUSTHAVECASTIRONCYLINDERLINERSORBECASTFROMANALUMINUMALLOYTHATHASSILICONPARTICLESINITSOMEMANUFACTURESMAKEANALUMINUMCYLINDERBLOCKTHATDOESNOTHAVECYLINDERLINERS,ORSLEEVESINSTEAD,THEALUMINUMISLOADEDWITHSILICONPARTICLESSILICONISAVERYHARDMATERIALAFTERTHECYLINDERBLOCKISCAST,THECYLINDERSAREHONEDTHENTHEYARETREATEDWITHACHEMICALTHATETCHESEATSAWAY,THESURFACEALUMINUMTHISLEAVESONLYTHESILICONPARTICLESEXPOSEDTHEPISTONANDRINGSSLIDEONTHESILICONWITHMINIMUMWEARPISTONTHEPISTONCONVERTSTHEPOTENTIALENERGYOFTHEFUELINTOTHEKINETICENERGYTHATTURNSTHECRANKSHAFTTHEPISTONISACYLINDRICALSHAPEDHOLLOWPARTTHATMOVESUPANDDOWNINSIDETHEENGINESCYLINDERITHASGROOVESAROUNDITSPERIMETERNEARTHETOPWHERETHERINGAREPLACEDTHEPISTONFITSSNUGLYINTHECYLINDERITHASGROOVESAROUNDITSPERIMETERNEARTHETOPWHERETHERINGSAREPLACEDTHEPISTONFITSSNUGLYINTHECYLINDERTHEPISTONSATEUSEDTOENSUREASNUG“AIRTIGHT”FITTHEPISTONINYOURENGINESCYLINDERARESIMILARTOYOURLEGSWHENYOURIDEABICYCLETHINKOFYOURLEGSASPISTONSTHEYGOUPANDDOWNONTHEPEDALS,PROVIDINGPOWERPEDALSARELIKETHECONNECTINGRODSTHEYARE“ATTACHED”TOYOURLEGSTHEPEDALSAREATTACHEDTOTHEBICYCLECRANKWHICHISLIKETHECRANKSHAFT,BECAUSEITTURNSTHEWHEELSTOREVERSETHIS,THEPISTONSLEGSAREATTACHEDTOTHECONNECTINGRODSPEDALSWHICHAREATTACHEDTOTHECRANKSHAFTTHEBICYCLERANKTHEPOWERFROMTHECOMBUSTIONINTHECYLINDERSPOWERSTHEFROMTHECOMBUSTIONRODSTOTURNTHECRANKSHAFTCONNECTINGRODTHECONNECTINGRODSHOWNINISMADEOFFORGEDHIGHSTRENGTHSTEELITTRANSMITSFORCEANDMOTIONFROMTHEPISTONTOTHECRANKPINONTHECRANKSHAFTASTEELPISTONPIN,OR“WRISTPIN”,CONNECTSTHESMALLENDOFTHECONNECTINGRODSOMERODSHAVEALOCKBOLTINTHESMALLENDASTHEPISTONMOVESUPANDDOWNINTHECYLINDER,THEPINROCKSBACKANDFORTHINTHEHOLE,ORBORE,INTHEPISTONTHEBIGENDOFTHECONNECTINGRODISATTACHEDTOACRANKPINBYARODBEARINGCAPCONNECTINGRODANDRODBEARINGCAPSAREASSEMBLEDDURINGMANUFACTURETHENTHEHOLDFORTHEBEARINGISBOREDWITHTHECAPINPLACETHISISCALLEDLINEBRINGITMAKEEACHRODANDITSCAPAMATCHEDSETUSUALLY,THESAMENUMBERISSTAMPEDONTHERODANDCAPTHISPREVENTSTHECAPSSETTINGMIXEDDURINGENGINESERVICEIFTHECAPSAREMIXED,THEBEARINGBOREWILLNOTBEROUNDANENGINEASSEMBLEDWITHTHERODBEARINGCAPSSWITCHEDWILLPROBABLYLOCKTHECRANKSHAFTIFTHECRANKSHAFTTURNS,THEBEARINGWILLPROBABLYHAVEIMPROPERCLEARANCEANDEARLYBEARINGFAILUREWILLRESULTANOTHERREASONFORKEEPINGTHECAPANDRODMATCHEDISTOPREVENTENGINEUNBALANCEANDUNWANTEDVIBRATIONALLCONNECTINGRODSINANENGINEMUSTBEASLIGHTASPOSSIBLEBUTTHEYMUSTALLWEIGHTHESAMEIFONERODISHEAVIERTHANTHEOTHER,THEENGINEWILLVIBRATETHISCOULDDAMAGETHEENGINECRANKSHAFTTHECRANKSHAFTTHENMAINROTATINGMEMBER,ORSHAFT,INTHEENGINEITHASCRANKPINS,TOWHICHTHECONNECTINGRODFROMTHEPISTONSAREATTACHEDDURINGTHEPOWERSTROKES,THECONNECTINGRODSFORCETHECRANKPINSANDTHEREFORETHECRANKSHAFTTOROTATETHERECIPROCATINGMOTIONOFTHEPISTONSISCHANGEDTOROTARYMOTIONASTHECRANKSHAFTSPINSTHISROTARYMOTIONISTRANSMITTEDTHROUGHTHEPOWERTRAINTOTHECARWHEELSTHECRANKSHAFTISASTRONG,ONEPIECECASTING,ORFORGING,ORHEATTREATEDALLOYSTEELITMUSTBESTRONGTOTAKETHEDOWNWARDFORCEOFPOWERSTROKESWITHOUTEXCESSIVEBENDINGITMUSTBEBALANCEDSOTHEENGINEWILLRUNWITHOUTEXCESSIVEVIBRATIONENGINEDISPLACEMENTTHEFREQUENTLYUSEDENGINESPECIFICATIONSAREENGINEDISPLACEMENTANDCOMPRESSIONRATIODISPLACEMENTANDCOMPRESSIONRATIONARERELATEDTOEACHOTHER,ASWEWILLLEARNINTHEFOLLOWINGPARAGRAPHSBYDISPLACEMENTENGINEDISPLACEMENTISTHEAMOUNTOFAIRDISPLACEDBYTHEPISTONWHENITMOVESFROTHEELECTRICALIGNITIONSYSTEMCAUSESASPARKACROSSTHESPARKPLUGELECTRODESINTHECYLINDERATTHEENDOFTHECOMPRESSIONSTROKE,WHICHIGNITESTHEVAPORIZEDFUELANDAIRMIXTUREMCOMPRESSINGTHEAIRTOIGNITETHEFUELWHENITISINJECTEDINTOTHECYLINDERATTHEENDOFTHECOMPRESSIONRATIOSAREMUCHHIGHERTHANGASOLINEENGINECOMPRESSIONRATIOS,SUFFICIENTHEATISGENERATEDBYCOMPRESSINGTHEAIRTOIGNITETHEFUEROFCYLINDERSENGINESARECLASSIFIEDASLOW,MEDIUM,HIGH,ANDSUPERHIGHSPEEDCOMMONLYUSEDTOINDICATEENGINESIZE,THISSPECIFICATIONISREALLYAMEASUREMENTOFCYLINDERVOLUMETHENUMBEROFCYLINDERSISAFACTORINDETERMININGDISPLACEMENT,BUTTHEARRANGEMENTOFTHECYLINDERSORVALVESISNOTENGINEDISPLACEMENTISCALCULATEDBYMULTIPLYINGTHENUMBEROFCYLINDERSINTHEENGINEBYTHETOTALENGINEDISPLACEMENTISTHEVOLUMEDISPLACEDBYALLTHEPISTONSTHEDISPLACEMENTOFONECYLINDERISTHESPACETHROUGHWHICHTHEPISTONSTOPSURFACEMOVESASITTRAVELSFROMTHEBOTTOMOFITSSTROKEBOTTOMDEADCENTERTOTHETOPOFITSSTROKETOPDEADCENTERITISTHEVOLUMEDISPLACEDBYTHECYLINDERBYONEPISTONSTROKEPISTONDISPLACEMENTCANBECALCULATEDASFOLLOWS1DIVIDETHEBORECYLINDERDIAMETERBYTWOTHISGIVESYOUTHERADIUSOFTHEBORE2SQUARETHERADIUSMULTIPLYITBYITSELF3MULTIPLYTHESQUAREOFTHERADIUSBY31416PIORTOFINDTHEAREAOFTHECYLINDERCROSSSECTION4MULTIPLYTHEAREAOFTHECYLINDERCROSSSECTIONBYTHELENGTHOFTHESTROKEYOUNOWKNOWTHEPISTONDISPLACEMENTFORONECYLINDERMULTIPLYTHISBYTHENUMBEROFCYLINDERSTODETERMINETHETOTALENGINEDISPLACEMENTTHEFORMULAFORTHECOMPLETEPROCEDUREREADSSTROKENOOFCYLINDERSDISPLACEMENTR2COMPRESSIONRATIOTHISSPECIFICATIONCOMPARESTHETOTALCYLINDERVOLUMETOTHEVOLUMEOFONLYTHECOMBUSTIONCHAMBERTOTALCYLINDERVOLUMEMAYSEEMTOBETHESAMEASPISTONDISPLACEMENT,BUTITISNOTTOTALCYLINDERVOLUMETHECOMBUSTIONCHAMBERVOLUMEWITHTHEPISTONATTOPDEADCENTERISOFTENCALLEDTHECLEARANCEVOLUMECOMPRESSIONRATIOISTHETOTALVOLUMEOFACYLINDERDIVIDEDBYITSCLEARANCEVOLUMEIFTHECLEARANCEVOLUMEISONEEIGHTHOFTHETOTALCYLINDERVOLUME,THECOMPRESSIONRATIOIS88TO1THEFORMULAISASFOLLOWSCOMPRESSIONRATIOOLUMECLEARNCVTTINTHEORY,THEHIGHERTHECOMPRESSIONRATIO,THEGREATERTHEEFFICIENCYOFTHEENGINE,ANDTHEMOREPOWERANENGINEWILLDEVELOPFROMAGIVENQUANTITYOFFUELTHEREASONFORTHISISTHATCOMBUSTIONTAKESPLACEFASTERBECAUSETHEFUELMOLECULESAREMORETIGHTLYPACKEDANDTHEFLAMEOFCOMBUSTIONTRAVELSMORERAPIDLYBUTTHEREAREPRACTICALLIMITSTOHOWHIGHACOMPRESSIONRATIOCANBEBECAUSEOFTHEUNAVAILABILITYOFHIGHOCTANEFUEL,MOSTGASOLINEBURNINGENGINESARERESTRICTEDTOACOMPRESSIONRATION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