1. Introduction to Engine Parts, Operation and Function
Chapter Lesson 1
Introduction to Engine Parts, Operation and Function

2. Engine Operation The engine is the source of power for the vehicle
It converts the energy stored in fuel into motion

3. Engine Operation
Fuel is burned inside the engine’s combustion chamber to produce heat
Heat causes expansion of gases in the engine
Expansion in the combustion chamber produces pressure
Engine components convert pressure into rotating motion

4. Engine Operation

5. Piston Travel (TDC, BDC)
Top dead center (TDC)
piston is at its highest point in the cylinder
Bottom dead center (BDC)
piston is at its lowest point in the cylinder
Piston stroke
distance the piston slides up or down from TDC to BDC

6. Piston Travel (TDC, BDC)

7. Four-Stroke Cycle Requires four piston strokes to complete one cycle
Every four strokes, the engine produces one power stroke
Two complete crankshaft rotations are required to complete the four-stroke cycle
Almost all automobiles use four-stroke-cycle engines

8. Intake Stroke Draws fuel and air into the engine Intake valve is open
Exhaust valve is closed
Piston slides down and forms a low pressure area in the cylinder
Atmospheric pressure pushes the air-fuel mixture into the cylinder

9. Compression Stroke
Compresses (squeezes) the air-fuel mixture, making it more combustible
Piston slides upward
Both valves are closed

10. Power Stroke
Burns the air-fuel mixture and pushes the piston down with tremendous force
Both valves are closed
Spark plug fires, igniting the air-fuel mixture
Pressure forms on the top of the piston
Piston is forced down, rotating the crankshaft

11. Exhaust Stroke Removes the burned gases from the cylinder
Piston moves upward
Intake valve is closed
Exhaust valve is open
Burned gases are pushed out the exhaust port

12. Four-Stroke Cycle

13. Engine Front End
Operates the engine camshaft and sometimes the oil pump, distributor, engine sensors, and diesel injection pump
Consists of a drive mechanism, a front cover, an oil seal, and a crankshaft damper

14. Camshaft Drive Needed to turn the camshaft at one-half engine speed
Often called the timing belt, timing chain, or timing gears because they time the camshaft with the crankshaft

15. Camshaft Drive
A belt-drive, chain-drive, or gear-drive may be used to turn the camshaft

16. Front Cover Bolts over the crankshaft snout
Holds an oil seal that seals the front of the crankshaft
When the engine uses a gear- or chain-type camshaft drive, the front cover may be called the timing cover

17. Engine Front End

18. Timing Belt
The front cover houses the front oil seal. The timing cover fits over the belt.

19. Timing chain and sprockets operate the camshaft in this engine

20. Crank Damper Heavy wheel on the crankshaft snout Mounted in rubber
Helps prevent crankshaft vibration and damage
Also called the harmonic balancer or vibration damper

21. Workbook Exercise Questions 1-6 and 45 – 47
Pages 145 – 147 and