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Transportation Technology. Engine Operation: 4 Stoke Cycle. C. Stemmler. 4 Four Stroke Engine. 4 Stroke Cycle. “cycle” is considered to be a repetitive series of operations
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Transportation Technology Engine Operation: 4 Stoke Cycle C. Stemmler 4 Four Stroke Engine
4 Stroke Cycle • “cycle” is considered to be a repetitive series of operations • 4 Stroke - requires the piston to move four times--up then down--four times to complete one cycle (two revolutions of the crankshaft) • most automotive & diesel truck engines are 4 stroke engines--due to emission laws
Intake valve 4 Stroke Cycle -- Intake Stroke • Piston Direction down TDC to BDC • Intake Valve open • Exhaust valve closed • Movement of gasesenters cylinder • Pressure 14 hg. of vacuum
Exhaust valve Compression Stroke • Piston Direction Up BDC to TDC • Intake Valve closed • Exhaust valve closed • Movement of gasessqueezed • Pressure 120 to 150 psi
Power Stroke • Piston Direction Down TDC to BDC • Intake Valve closed • Exhaust valve closed • Movement of gasesrapid expansion • Pressure 800 to 1000psi
Exhaust Stroke • Piston Direction Up BDC to TDC • Intake Valve closed • Exhaust valve open • Movement of gasesexpelled or pushed out • Pressure 20 to 30psi
4 Stroke Cycle - Complete • There are crankshaft revolutions in one cycle - which is degrees of crankshaft rotation rotation. two 720 180 • The crankshaft turns degrees during one stroke. once • The camshaft turns in one complete cycle - which is degrees of crankshaft rotation. 720