1. ENGINE DESIGN AND OPERATION

2. ENGINE CLASSIFICATIONS n VALVE ARRANGEMENT n CAMSHAFT LOCATION n IGNITION TYPE n CYLINDER ARRANGEMENT n NUMBER OF CYLINDERS n CYCLES

3. HOW THE ENGINE WORKS

4. CRANKSHAFT

5. PISTON and ROD n Cast Piston n Forged Piston

6. PISTON CONFIGURATIONS n Inline 6 n Inline 4 n Opposed 4 n V-6 n V-8

7. DEFINITIONS n TDC –Top Dead Center –Piston at top of stroke. n BDC –Bottom Dead Center –Piston at Bottom of stroke. n STROKE –TDC to BDC –BDC to TDC –180 degrees of crankshaft rotation n FOUR CYCLE (Stroke) –4 x 180 = 720 degrees to make one complete cycle.

8. FOUR STROKE CYCLE n Intake Compression Compression n Power n Exhaust

9. INTAKE STROKE n Intake valve open n Exhaust valve closed n piston traveling down from TDC to BDC n Air is being forced into the cylinder by the difference between atmospheric and cylinder pressure

10. VACUUM DEFINITION n Any pressure less than atmospheric in a sealed or semi-sealed container n Approximately 14.7 psi at sea level

11. COMPRESSION STROKE n Both valves closed n Piston traveling up BDC to TDC n Compressing the air- fuel mixture

12. POWER STROKE n Both valves closed n Spark plug ignites the air fuel mixture n Piston is being pushed down by the expanding gases from TDC to BDC

13. EXHAUST STROKE n Exhaust valve open n Intake valve closed n Piston traveling up from BDC to TDC forcing the burnt exhaust gases from the cylinder

14. n At TDC the engine has returned to its starting point.

15. ENGINE MEASUREMENTS n BORE –BORE GREATER THAN STROKE IS OVERSQUARE n DISPLACEMENT –VOLUME OF CYLINDER BETWEEN TDC AND BDC n COMPRESSION RATIO –RATIO OF CYLINDER VOLUME AT TDC VERSUS BDC

16. ENGINE EFFICIENCY n THERMAL EFFICIENCY –Relationship between power output and the heat energy in the fuel n MECHANICAL EFFICIENCY –Relationship between the engine power delivered and the power that would be delivered if there was no friction, etc. n VOLUMETRIC EFFICIENCY –Relationship of air taken into the cylinder versus amount required to fill the chamber

17. CAMSHAFTS n Camshafts turn at one half crankshaft speed. n Camshafts can be driven with a gear, chain and sprocket, or toothed belt. RK

18. Valve Train

19. That’s All Folks!