1. Engine Construction & Principles of Operation page 63
Chapter 4
Engine Construction & Principles of Operation
page 63

2. Gasoline Engines
A gasoline fueled engine is a mechanism designed to transform the chemical energy of burning fuel into mechanical energy.
Single cylinder
Multi-cylinder
V-inline-
Rotary
All have similar Fuel systems, Cooling and lubrication systems.

3. Simple Engine operation
Intake
fuel/air
Compression
compress it
Power
Spark
Exhaust
get rid of it
4 Cycles

4. Gasoline HydroCarbon (HC) Refined from Petroleum Must: Ignite readily
Burn Cleanly
Resist detonation
Vaporize easily
w/o impeding flow-
Be free of dirt

5. Gasoline Assign Octane # 87-89-93 Higher # for higher compression
Shelf life
Leaded/Lead Free
Tetraethyl lead
Additives
Ethanol
Methanol
ether

6. Gas MUST Burn Quickly Not over 10% Ethanol
Liquid gas burns cold & Slow

7. Fuel is Atomized Must be in mist/vapor/atomized Increase surface area
Droplets
(Spray paint, Air brush, mist)

8. Explosion must be contained
Need to contain to perform work
Tube
Sliding plug
Cap
Inlet\Outlet
Direct the flame/explosion

9. Further Improvements Limit area of Explosion Tube = Cylinder
Sliding Plug = Piston
Cap = Head
Inlet/Outlet = Valves

10. Basics for an Engine Systems of the engine Mechanical Carburetion
Ignition
Cooling
Lubrication

11. Cylinder Block Frame of engine Keeps parts in alignment
Iron or Aluminum
Holes “Bored”
Cooling fins
Water Jacket

12. Crankshaft Major Rotating part
Changes Reciprocating motion into rotary motion
Fly Wheel/Snout
Output
Counter weights
Crank pin / connecting rod journal
Throw
Key way

13. Crankcase
Rigid
Hold seals
Hold oil
Extreme pressure

14. Piston Sliding plug Expands during operation Ring grooves
Piston pin/wrist pin
Head constructions

15. Pistons

16. Connecting Piston to Crankshaft
Wrist Pin
Retaining clips
Connecting Rod
Bearings
Cap
Retainer
Bolts

17. Intake & Exhaust Ports Ports (openings) Passages
                               
Intake & Exhaust Ports
Ports (openings)
Passages
Capped w/ poppet valves

18. Poppet Valves
4 stroke engines
Door ways
Pop open
Sit in Valve guides

19. Valve Spring Assembly Holds valve in place Closes valve Valve Spring
Retainer
Keeper

20. Valve Lifters/Tappets
Rides on Camshaft
Taps/Lifts Valves
Some adjustable

21. Cam Shaft Controls OPENING of valves Duration (time) Reach (distance)
½ crank speed
www.

22. Fly Wheel smoothes engine operation Magnets cast into Key way/groove
Metal fins
cooling
Clutch