4 Stroke Engine cycle

1. 4 Stroke Engine cycle Part 1 http://www.youtube.com/watch?v=4HPV73v7Ub8

2. 4 Stroke Engine cycle

3. Engine displacement • A cylinders displacement is the volume of the cylinder when the piston is at BDC. • It is the sum of the displacement of each cylinder. • It is defined as the volume of air/fuel mixture an engine can draw in.

4. Engine displacement Ex: 700 cc (cubic centimetres) 1000 cc = 1 Litre

5. Engine displacement Example : Vehicle has 4 cylinders : Each cylinder has a volume of 700cc : 700cc X 4 = 2800cc : 2800cc = 2.8 Litre

6. Torque • Torque is the term used to describe a rotating force. • More torque generally means a car can accelerate faster • Torque is the actual reading of how “hard” and with how much “Force” the engine turns.

7. Horsepower • Horsepower: 1 hp = 33,000 lb-ft / min • One horsepower is the ability to lift 33000 pounds one foot in one minute • The horsepower specification for an engine tells you how much power the engine can produce.  • Horsepower is the rate at which the engine does work

8. Horsepower calculations Formula: • HORSEPOWER = (TORQUE * RPM) / 5252 • A engine that makes 300 pound-feet of torque at 4,000 RPM produces • [(300 x 4,000) / 5,252] 228 horsepower at 4,000 RPM

9. Torque and Horsepower • Think about: • Torque being how hard you can pound away on bicycle pedals • Horsepower being how fast you can spin the bicycle pedals.

10. Recap • What is engine displacement? • What is horsepower? • What is Torque? • What are the different parts of an engine?

11. The 4 stroke cycle • http://www.youtube.com/watch?v=60QX5RY_ohQ&feature=related • Part 2

12. The four-stroke engine Spark plug Exhaust valve Inlet valve Cylinder Piston

13. Piston, connecting rod, crankshaft • Is a can-shaped part closely fitted inside the cylinder. • Piston rings consist of compression rings and oil rings. • Crankshaft takes the up-down motion of the piston and convertors it to a rotation motion • Connecting rod connects the piston to the crankshaft.

14. What is the 4 Stroke cycle? • The 4 Stroke engine cycle consist of these: 1) Intake 180degree 2) Compression 180 degree 3) Power/ Combustion 180 degree 4) Exhaust 180 degree • Total engine revolution 720 degree • One complete engine cycle consists of 4 engine strokes.

15. Intake • The Intake Stroke consist of the piston travelling down. • Intake valves are open to allow Air/Fuel mixture to come into the combustion chamber.

16. Intake system • Intake plastic ducts • Intake manifolds

17. Intake system

18. Intake system • Fuel injectors are electronically controlled valves that spray fuel to mix with air. • Creating that air fuel mixture

19. Spark plugs • It is an electrical device that fits into the cylinder head and ignites air fuel mixtures.

20. The four-stroke engine Inlet valve open Exhaust valve closed INTAKE STROKE

21. The four-stroke engine Inlet valve open Exhaust valve closed INTAKE STROKE Piston down

22. The four-stroke engine Fuel in Inlet valve open Exhaust valve closed INTAKE STROKE Piston down

23. The four-stroke engine Fuel in Exhaust valve closed Inlet valve open INTAKE STROKE Piston down

24. Recap • What is the purpose of the intake system? • What is the purpose of the spark plug? • What is the purpose of the fuel injector? • What is happening during the intake stroke?

25. 4 Stroke engine • Part 3 • http://www.youtube.com/watch?v=q4Bk2TJJ6TM

26. Compression • Compression stroke consist of the piston travelling back up. • Both intake and exhaust valves are closed • Air fuel mixture is now being compressed

27. The four-stroke engine Piston up Exhaust valve closed Inlet valve closed COMPRESSION STROKE

28. The four-stroke engine Piston up Inlet valve closed Exhaust valve closed COMPRESSION STROKE

29. The four-stroke engine Piston up Inlet valve closed Exhaust valve closed COMPRESSION STROKE

30. Combustion/Power • The piston is now at the TDC • Spark plug ignites, creating a spark that ignites the compressed air fuel mixture. • Explosion is created and the piston is forced back down. • Hence the Power stroke • Both valves are still closed

31. The four-stroke engine Inlet valve closed Exhaust valve closed BANG POWER STROKE

32. The four-stroke engine Inlet valve closed Exhaust valve closed Piston down powerfully POWER STROKE

33. The four-stroke engine Inlet valve closed Exhaust valve closed POWER STROKE Piston down powerfully

34. The four-stroke engine Inlet valve closed Exhaust valve closed POWER STROKE

35. Exhaust • Exhaust stroke the piston is travelling up • Exhaust valve is open • Intake valve is Closed • Exhaust gases being pushed out by piston

36. The four-stroke engine Inlet valve closed Exhaust valve closed EXHAUST STROKE

37. The four-stroke engine Piston up Inlet valve closed Exhaust valve open Exhaust gases out EXHAUST STROKE

38. The four-stroke engine Piston up Inlet valve closed Exhaust valve open Exhaust gases out EXHAUST STROKE

39. The four-stroke engine Inlet valve open Exhaust valve closed INTAKE STROKE

40. And so the cycle continues!!

41. Exhaust system • The exhaust system is needed to provide a pathway for exhaust fumes to be filtered and to reduce noise. • Exhaust manifold • Catalytic convertor • Muffler

43. Recap • What is the purpose of the compression stroke and what is happening • What is the purpose of the power stroke and what is happening? • What is happening during the exhaust stroke? • What is the purpose of the exhaust system?

44. Video of 4 Stroke cycle http://www.youtube.com/watch?v=IYWUWMmimjQ&feature=related http://videos.howstuffworks.com/auto/car-parts-videos-playlist.htm#video-30374

45. QUIZ

46. 4 Stroke cycle • http://www.youtube.com/watch?v=YB_JCUw9SoU&feature=related