1. Basic Engine Operation & Construction
Purpose of an engine - To create power for a specific use!
Use for What?
Purpose of an Piston type engine - To create power for a specific use and
convert reciprocating power to rotary power
How do you create Power?
Easy !!
A Potato Gun !!! How does it work!!
Converting reciprocating power to rotary power is done with three basic parts
It’s just like
riding a bike !
What are other uses for straight line power ?
Rotary Power is more usefull !

2. External Combustion or Internal Combustion
Combustion: the act or process of burning, creating pressure for a specific use!
External Combustion:
Pressure/Power created outside of the engine
Ie: Steam Engines
Web Link
Internal Combustion:
Pressure/Power created inside of the engine
Ie: Four Stroke Cycle Engines
Web Link

3. Creating Internal Combustion
Vacuum – Low Pressure Area, air moves “High to Low”

4. Creating Internal Combustion
Compressing the
A/F mixture
makes it more volatile! Why?
Compression Creates
Energy
Heat
An super active
A/F mixture
Compress the A/F to much add !
Pre-Ignition!

5. Creating Internal Combustion
Ignition starts the burning
of the A/F mixture
Power – burning A/F mixture
Combustion Completed

6. Creating Internal Combustion
Remove the burnt
A/F Mixture via pressure
Start Over! How?
Done!

7. Welcome to the Four Stroke Cycle
Intake
Compression
Power
Exhaust
Animated 4 Stroke

8. Basic Engine Terminology

9. The Four Stroke Cycle
Intake - Intake valve opens, piston travels from TDC to BDC, creating a vacuum, drawing in air/fuel mixture into the combustion camber. Intake valve closes.
Compression - Both valves closed, piston travels from BDC to TDC compressing the air/fuel mixture. A volatile mixture, and heat are created.
Power - air/fuel mixture is ignited and begins to burn, and expands. the pressure forces the piston down from TDC to BDC causing the crankshaft to turn.
Exhaust - exhaust valve opens, piston moves from BDC to TDC forcing out the burnt gases remaining from the created power. Exhaust valve closes
CYCLE REPEATS

10. Engine Classification
Number of Cylinders: .
Cylinder Arrangements:
Valve Train types:
Fuel Types:
Cooling System:
Ignition Types:

11. Number of Cylinders & Cylinder Arrangements
Inline:
V-Type
Opposed
2, 4, 6
2, 4,6, 8, 10,12, 16
1, 2, 3, 4, 5, 6, 8
Animation Link
Cylinder Numbering
Firing Order:
the order in which each cylinder begins its power stroke

12. Other Piston Cylinder Arrangements
Radial
W12
Radial Animation

13. Engine Classification
Number of Cylinders: .
Cylinder Arrangements:
Valve Train types:
Fuel Types:
Cooling System:
Ignition Types:

14. Valve Train Types
L Head
T Head
F Head
I Head

15. How valves Open and Close
Briggs & Stratton L Head Design
Mechanically with
A Cam Lobe
Valve Timing with gear ratio’s
Camshaft
Crankshaft
Camshaft
Crankshaft
1 : 1
1 : 2

16. How valves Open and Close
T Head
F Head
I Head
Animated I Head

17. How valves Open and Close
Overhead Camshaft
DOHC
Double Over Head Cam

18. Engine Classification
Number of Cylinders: .
Cylinder Arrangements:
Valve Train types:
Fuel Types:
Cooling System:
Ignition Types:

19. Fuel Types Advantages Disadvantages Gasoline Propane Natural Gas
- different octane levels
- availability
- highest polluting
Gasoline
cost
low polluting
power loss 10%
availability
Propane
power loss 20%
availability
- carrying danger
- cost, cheapest
- very low polluting
Natural Gas
high octane
- Very low polluting
high cost
- poor fuel economy
Alcohol
cost, better fuel economy
lots power/torque
- long lasting
high polluting
engine cost
- noise / low RPM
Diesel

20. Engine Classification
Number of Cylinders: .
Cylinder Arrangements:
Valve Train types:
Fuel Types:
Cooling System:
Ignition Types:

21. Cooling System / Ignition Type
Air
Cooled
Spark
Liquid
Cooled
Compression

22. Other Engine Types Diesel Engine
Diesel Fuel oil – by product from the crude oil refining process.
- rated by cetane number, difficult to ignite
Compression
Air Only
Creating Heat
Power
Hot Air Ignites
Injected Diesel
Exhaust
Burnt A/F
Pushed Out
Intake
Air Only

23. Other Engine Types Diesel Engine Diesel Injectors must:
Enter correct amount of fuel
Be at the right time
Control the rate of fuel
Start and stop abruptly
Advantages
- cost, better fuel economy
- lots power/torque
- long lasting
Disadvantages
slow acceleration
low RPM
- engine cost
fuel system repairs
noise

24. Other Engine Types Two Stroke Cycle Basic operating principles
- similar to a 4 stroke, operating principles of Intake, Compression, Power and Exhaust.
- the above principles are completed in two strokes instead of four, stages are combined
How do you combined
4 strokes into 2 ?
Exhaust
Intake
Compression
Power

25. Other Engine Types Two Stroke Cycle Intake
- intake port is cleared by the piston
- Air/Fuel mixture is pushed into
the combustion chamber.
Compression
only occurs for aprox. 1/2
of the piston movement up
Compression

26. Other Engine Types Two Stroke Cycle Power
- only occurs for aprox. the first 1/2 of the piston moving down.
Exhaust
- exhaust port is cleared by the piston.
exhaust to escapes from the pressure
of the power stroke
Exhaust
CYCLE REPEATS
Animated 2 stroke

27. Other Engine Types Two Stroke Cycle Other Operating Principles
How is the A/F pushed into the combustion camber?
A/F mixture is drawn into the crankcase as the piston is moving up during the power stage by a vacuum in the crankcase, drawing in the air/fuel/oil mixture
Animated 2 stroke
As the moves down on the power stage, pressure is created in the crankcase, therefore forcing the A/F mixture into the combustion camber

28. Other Engine Types Two Stroke Cycle Advantages Disadvantages
less moving parts,
no valves
- runs at any angle
high revving
fast acceleration
Disadvantages
- high wear rate
- low torque
- lubrication needs to be mixed or injected
- high in pollutants

29. Other Engine Types Two Stroke Diesel
Similar operating principle of the two stoke gasoline engine.
However: the crankcase is not used to create pressure!
Air is forced by a blower!

30. Other Engine Types Two Stroke Diesel Advantages Disadvantages
- better fuel economy
- lots power/torque
- long lasting
- less moving parts
higher revving
faster acceleration
Disadvantages
- engine cost
- fuel system repairs
- noise

31. Other Engine Types Rotary Combustion Turbine / Jet engines
Not a reciprocating motor - motion of operation is already in rotary motion
Turbine / Jet engines
WANKEL ENGINES
Bingo! A Wankel!
Imagine a spinning triangular block inside a can!
The cambers on each side do not change volume.
However! If the triangle is turning of centre, the camber change volume as it rotates.

32. Other operating principles
Other Engine Types
Rotary Combustion
Basic Operating Principles – Stages
Stage 1 - rotor clears intake port, chamber increases in size, creating a vacuum drawing in A/F mixture
Other operating principles
- three chambers acting at the same time doing different stages
- some motors wth two rotors therefore six power thrust for one revolution
- power to crankshaft done with gears on an eccentric
- 3 to 1 ratio of rotor to crankshaft rotation
Stage 2 - rotor continues to rotate, intake port closed off, chamber begins to compress A/F mixture
Stage 3 - A/F mixture ignited by spark plug, burning creating power against rotor continuing rotary motion
Stage 4 - turning rotor uncovers exhaust port, forcing out exhaust gases as chamber is decreasing
STAGES REPEAT
Wankel Animation

33. Other Engine Types Rotary Combustion Advantages Disadvantages
- fewer moving parts
- less power loss to friction
- 1/2 size / hp of piston engine
- almost vibration less
- quite running
- great acceleration
- constant torque
- high RPM obtained
Disadvantages
rapid wear of appex seals
repair costs
- poor fuel economy
- high in air pollutants