1. Four-Stroke Engine Basics
Cars
Trucks
Semis
Tractors
Airplanes
Motorcycles
Lawnmowers

2. The Basics A four-stroke engine: Is an internal combustion engine
Converts gasoline into motion
Is the most common car engine type
Is relatively efficient 20%
4 piston strokes per cycle
2 crankshaft revolutions per cycle

3. Basic Components Camshaft Intake Valve Exhaust Valve Spark Plug
Valve Cover
Spark Plug
Intake Port
Exhaust Port
Head
Piston
Connecting Rod
Coolant
Rod Bearings
Engine Block
Crankshaft
Oil Pan
Oil Sump

4. The 4-Stroke Cycle 1. Intake 2. 3. Compression 4. Combustion Exhaust
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5. Intake process of filling the cylinder with the proper air-fuel mixture through the intake valve.
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6. Compression the process of compressing the air-fuel mixture in the cylinder to make it more combustible
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7. Combustion the process of igniting the compressed air-fuel mixture to create motion and the over all power of the engine.
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8. Exhaust the process of releasing the exhaust out of the cylinder through the exhaust valve.

9. How Stuff Works Animation

10. Engine Block- cast in one piece
Engine Block- cast in one piece. The basis for most of the parts of the engine.
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11. Valve Cover- Protects the valves and the valve springs
Valve Cover- Protects the valves and the valve springs. Keeps dirt out and lubricating oil in.

12. Head- a platform containing most of the parts of the combustion chamber.

13. Intake Valve- opens at the proper time to let in air and fuel.
Intake Port- the passageway in a cylinder head for the fuel and air to pass through.

14. Exhaust Valve- open at the proper time to release the exhaust Exhaust Port- the passageway in a cylinder head, for the exhaust to pass through

15. Valve Guide
Controls the position of the valves

16. Lubrication
Oil Pan where the oil is collected and recirculated primarily for lubricating the crankshaft and rod bearing
Oil Sump where the oil is stored for lubrication

17. Camshaft- a round shaft with lobes, that rotates to open and close the fuel and exhaust valves. Aligned with crankshaft gear for proper timing

18. Spark Plug a device, inserted into the combustion chamber for firing an electrical spark to ignite air-fuel mixture

19. Cylinder
Three types
Cast aluminum
Cast aluminum with cast iron sleeve
Cast iron
Usually use a cross-hatch finish to improves ring lubrication

20. Piston the part of the engine that moves up and down in the cylinder converting the gasoline into motion

21. Piston Rings-Keep tight seal against cylinder wall

22. Ring Grooves
Ring grooves are machined grooves in the piston designed to hold the rings.
Ring lands are the areas of the piston between the ring grooves.
The clearance between the rings and the ring lands is critical.

23. Connecting Rod- links the piston to the crankshaft.
Rod Bearing- used to reduce friction to the rod and crankshaft

24. Crankshaft- converts the up and down (linear) motion of the piston into a turning, or rotating motion

25. Crankcase Breather
Maintains pressure in the crankcase at less than ambient pressure to assist in the control of oil consumption.
Excessive blow by renders the breather useless.
Old engines vent to the atmosphere.
New engines vent to the carburetor.

26. Application
Now that you understand the basics of four-stroke engines, how can you use this information in the real world?
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Quiz

27. Lets take a quiz to see what you have learned!
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Quiz

28. 1. The ____ controls the amount of intake and the release of exhaust. a. head b. valves c. coolant d. connecting rod

29. The _____ Cycle is the ignition of the compressed fuel-air mixture.
a. Exhaust
b. Combustion
c. Compression
d. Intake

30. The most common type of engine?
a. diesel engines
b. 2-stroke engines
c. rotary engines
d. 4-stroke engines

31. What part of the engine converts up and down motion into a rotation motion?
a. crankshaft
b. piston
c. valve cover
d. camshaft

32. What is the name of the part listed?
a. intake valve
b. piston
c. oil pan
d. spark plug

33. Congratulations! That is the end of your quiz, and the end of your lesson on four-stroke engines.
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34. Four Stroke Chart
Stroke
Piston Movement
Intake Valve
Exhaust Valve

35. Compare & Contrast 2 & 4 Cycle Engines