Chapter 4Engine Construction & Principles of Operationpage 63

Gasoline EnginesA gasoline fueled engine is a mechanism designed to transform the chemical energy of burning fuel into mechanical energy. Single cylinderMulti-cylinderV-inline-RotaryAll have similar Fuel systems, Cooling and lubrication systems.

Simple Engine operationIntakefuel/airCompressioncompress itPowerSparkExhaustget rid of it

http://auto.howstuffworks.com/engine1.htm4 Cycles

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GasolineHydroCarbon (HC)Refined from PetroleumMust: Ignite readilyBurn CleanlyResist detonationVaporize easilyw/o impeding flow- Be free of dirt

GasolineAssign Octane # 87-89-93Higher # for higher compressionShelf lifeLeaded/Lead FreeTetraethyl leadAdditivesEthanolMethanolether

Gas MUST Burn QuicklyNot over 10% EthanolLiquid gas burns cold & Slow

Fuel is AtomizedMust be in mist/vapor/atomizedIncrease surface areaDroplets (Spray paint, Air brush, mist)

Explosion must be containedNeed to contain to perform workTubeSliding plugCapInlet\OutletDirect the flame/explosion

Further ImprovementsLimit area of ExplosionTube = CylinderSliding Plug = PistonCap = HeadInlet/Outlet = Valves

Basics for an EngineSystems of the engineMechanicalCarburetionIgnitionCoolingLubrication

Cylinder BlockFrame of engineKeeps parts in alignmentIron or AluminumHoles BoredCooling finsWater Jacket

CrankshaftMajor Rotating partChanges Reciprocating motion into rotary motionFly Wheel/SnoutOutputCounter weightsCrank pin / connecting rod journalThrowKey way

CrankcaseRigidHold sealsHold oilExtreme pressure

PistonSliding plugExpands during operationRing groovesPiston pin/wrist pinHead constructions

Pistons

Connecting Piston to CrankshaftWrist PinRetaining clipsConnecting RodBearingsCapRetainerBolts

Intake & Exhaust PortsPorts (openings)PassagesCapped w/ poppet valves

Poppet Valves4 stroke enginesDoor waysPop openSit in Valve guides

Valve Spring AssemblyHolds valve in placeCloses valveValveSpringRetainerKeeper

Valve Lifters/TappetsRides on CamshaftTaps/Lifts ValvesSome adjustable

Cam ShaftControls OPENING of valvesDuration (time)Reach (distance) crank speed

www. http://auto.howstuffworks.com/camshaft.htm

Fly Wheelsmoothes engine operationMagnets cast intoKey way/grooveMetal fins coolingClutch

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