1. Engine Terminology Engine Dynamics The Four Strokes Lesson 6 March 2008

2. Spot Quiz  Laws of Mechanics  Top 5  Bottom 5  Applied Laws of Mechanics YouTube - 3D animation of a car engine

3.  the correct fuel charge must be delivered to the cylinder at the correct time.  ignition of the fuel charge must occur at the correct time.  the cylinder must be purged of spent gasses at the correct time. In order for an engine to function properly:

4. Simplified An easier way to remember is that an engine must have:  Spark  Fuel  Time

5. Engine breathing dynamics 1) Intake 2) Compression 3) Power 4) Exhaust

6. Crankshaft – stroke control In true terms, a stroke is the upward or downward movement of the piston in the cylinder from TDC to BDC once (1)

7. TDC - BDC BDC – means Bottom Dead Centre TDC – means Top Dead Centre

9. The ‘stroke' is the measurement between crankshaft main journal and connecting rod journal (throw) multiplied by 2

10. Crankshaft Rotation- 4 strokes 720 degrees (two revolutions) 0 - 180180-360360-540540-720

11. The 4 Events Intake (suck) Compression (squeeze) Power (bang) Exhaust (blow)

13. Camshaft-the breathing brain

14. Remember how the Crankshaft sees 720 degrees ? 0 - 180180-360360-540540-720

15. How the Camshaft views 720 degrees of Crankshaft rotation How many times did the camshaft turn to complete all four events?

16. Crank-Cam Connection Mechanical Valve Timing The camshaft is timed (aligned) to the crankshaft so that the valve ‘events’ occur during the appropriate ‘stroke’. This alignment must be precise or engine damage could occur.

17. Timing Marks (Cam and Crank in sync)

18. Remember Stroke is the piston moving from TDC to BDC once (controlled by crankshaft) Event is opening and closing of valves (controlled by camshaft and valve springs)

19. The 10 Pieces - Intake Stroke Cause and Effect (advanced diagnostics) Block Piston (rings) Wrist pin Connecting Rod Crankshaft Head Valve Spring Cam Belt (or other drive) Top EndBottom End

20. Intake Stroke and Event  Intake valve OPEN  Exhaust valve CLOSED  Piston on down stroke

21. The 10 Pieces-Compression Stroke Cause and Effect (advanced diagnostics) Block Piston (rings) Wrist pin Connecting Rod Crankshaft Head Valve Spring Cam Belt (or other drive) Top EndBottom End

22. Compression Stroke and Event  Both valves CLOSED  Piston on upward stroke

23. The 10 Pieces- Power Stroke Cause and Effect (advanced diagnostics) Block Piston (rings) Wrist pin Connecting Rod Crankshaft Head Valve Spring Cam Belt (or other drive) Top EndBottom End

24. Power Stroke and Event  Both valves CLOSED  Piston on downward stroke

25. The 10 Pieces-Exhaust Stroke Cause and Effect (advanced diagnostics) Block Piston (rings) Wrist pin Connecting Rod Crankshaft Head Valve Spring Cam Belt (or other drive) Top EndBottom End

26. Exhaust Stroke and Event  Intake valve CLOSED  Exhaust valve OPEN  Piston on upward stroke YouTube - How Engines Work YouTube - Soldiers blow up washing machine with a grenade