4 stroke engines | Tài liệu Môn Công nghệ kĩ thuật Ô tô Trường đại học sư phạm kỹ thuật TP. Hồ Chí Minh

Whatdoknowabout4‐strokeengines?
‐Theyareinternalcombustionengines.
‐Howaretheyusedincars?
‐Whatisthemostcommontypeofengineusedincars today?
‐Howabouttheefficiency?
‐Andthecost?
‐Whatabouttheirworkingcycle?
4– Strokeworkingcycle e
C‐D:Combustion Piston ssur Crankshaft re P C
B‐C:Compression 1.Intake
2.Compression
D‐E:Exhaust D A B Volume E
A‐B:Intake
3.Ignition/Combustion/ 4.Exhaust
Power/working Unit4: Four‐StrokeEngine
• Afour‐strokeengine:
– Isaninternalcombustionengine
– Convertsgasolineintomotion
– Isthemostcommoncarenginetype
– Isrelativelyefficient
– Isrelativelyinexpensive
BasicComponentsofFour‐StrokeEngines Camshaft IntakeValve ExhaustValve ValveCover SparkPlug IntakePort ExhaustPort Head Piston ConnectingRod EngineBlock Crankshaft Next Diagram Back
• A.IntakeValve‐ opensatthe
propertimetoletinairandfuel.
• C.IntakePort‐ thepassagewayin
acylinderheadforthefueland airtopassthrough.
• J.ExhaustValve‐ openatthe
propertimetoreleasethe exhaust
• L.ExhaustPort‐ thepassagewayin
acylinderhead,fortheexhaustto passthrough
• B.ValveCover‐ Protectsthe
valvesandthevalvesprings.
Keepsdirtoutandlubricatingoil Back in. ValveandRelatedParts Camshaft Valve stem Valve guide bushing Oil seal Valve face 44.5° Valve head or 45.5° Exhaust Intake valve valve Exhaust valve Intake valve Combustion chamber Back
• D.Head/cylinderhead‐ aplatform
containingmostofthepartsofthe combustionchamber. Back
• F.EngineBlock‐ castinonepiece.Thebasis
formostofthepartsoftheengine. Back
• I.Camshaft‐ aroundshaftwithlobes,thatrotatesto
openandclosetheintakeandexhaustvalves. Drivegears
IntakeCamshaft Timingbelt
ExhaustCamshaft Back Crankshaft
• K.SparkPlug‐ adevice,insertedintothe
combustionchamberforfiringanelectrical
sparktoigniteair‐fuelmixture Back
• M.Piston‐ thepartoftheenginethatmoves
upanddowninsidethecylinder. Back
• N.ConnectingRod‐ linksthepistontothe crankshaft.
Connectingrod Back
• P.Crankshaft‐ convertstheupanddownmotion
ofthepistonintoaturning,orrotatingmotion
Pistonrings Piston Pistonpin Back Connecting Crankshaft Crankshaft Flywheel  
rodbearing bearing journal The4‐StrokeCycle • 1. Intake • 2. Compression • 3. Combustion • 4. Exhaust Back Next
• Intake‐ processof fillingthecylinder withtheproperair‐ fuelmixturethrough theintakevalve. Back
• Compression‐ the processofcompressing
theair‐fuelmixturein
thecylindertomakeit morecombustible Back • Combustion‐the process of igniting the compressed air‐fuel mixture to create motion and the over all power of the engine. Back
• Exhaust‐ theprocess ofreleasingthe exhaustoutofthe cylinderthroughthe exhaustvalve. Back
• Letstakeaquiztoseewhatyouhavelearned! Back Quiz