1. Transportation Technology Engine Operation: 4 Stoke Cycle C. Stemmler 4 Four Stroke Engine

2. 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

3. 4 Stroke Cycle -- Intake Stroke ?Piston Directiondown TDC to BDC ?Intake Valveopen ?Exhaust valveclosed ?Movement of gases enters cylinder ?Pressure14 hg. of vacuum Intake valve

4. Compression Stroke ?Piston DirectionUp BDC to TDC ?Intake Valveclosed ?Exhaust valveclosed ?Movement of gases squeezed ?Pressure120 to 150 psi Exhaust valve

5. Power Stroke ?Piston DirectionDown TDC to BDC ?Intake Valveclosed ?Exhaust valveclosed ?Movement of gases rapid expansion ?Pressure800 to 1000 psi

6. Exhaust Stroke ?Piston DirectionUp BDC to TDC ?Intake Valveclosed ?Exhaust valveopen ?Movement of gases expelled or pushed out ?Pressure20 to 30 psi

7. ?The camshaft turns in one complete cycle - which is degrees of crankshaft rotation. ?The crankshaft turns degrees during one stroke. ?There are crankshaft revolutions in one cycle - which is degrees of crankshaft rotation rotation. 4 Stroke Cycle - Complete two 720 180 once 720