1. Engine Design
Classifications

2. Engine Classifications
Even though basic parts are the same, design differences can change the way engines operate and how they are repaired
For this reason, you must be able to classify engines

3. Common Engine Classifications
Cylinder arrangement
Number of cylinders
Cooling system type
Valve location
Camshaft location
Type of fuel burned
Type of aspiration

4. Cylinder Arrangement
Refers to the position of the cylinders in relation to the crankshaft
There are five basic cylinder arrangements:
inline
V-type
slant
W-type
opposed

5. Cylinder Arrangement

6. Number of Cylinders
Most car and truck engines have either 4, 6, or 8 cylinders
Some may have 3, 5, 10, 12, or 16 cylinders
Engine power and smoothness are enhanced by using more cylinders

7. Cooling System Type There are two types of cooling systems:
Liquid cooling system
surrounds the cylinder with coolant
coolant carries combustion heat out of the cylinder head and engine block
Air cooling system
circulates air over cooling fins on the cylinders
air removes heat from the cylinders

8. Cooling System Type
A. Air cooling
B. Liquid cooling

9. Fuel Type Engines are classified by the type of fuel used: Gasoline
Diesel
Liquefied petroleum gas (LPG),
gasohol (10% alcohol, 90% gasoline), and pure alcohol may also be used

10. Valve Location Engines are classified by the location of the valves:
L-head engine
also called a flat head engine
I-head engine
also called an overhead valve (OHV) engine

11. Both the intake and exhaust valves are in the block
L-Head Engine
Both the intake and exhaust valves are in the block

12. Both valves are in the cylinder head
I-Head Engine
Both valves are in the cylinder head

13. Camshaft Location
There are two basic locations for the engine camshaft:
Camshaft located in the block
cam-in-block engine
Camshaft located in the cylinder head
overhead cam (OHC) engine

14. Cam-in-Block Engine
Uses push rods to transfer motion to the rocker arms and valves
Also called an overhead valve (OHV) engine

15. Camshaft is located in the top of the cylinder head
Overhead Cam Engine
Camshaft is located in the top of the cylinder head

16. Overhead Cam Engine Single overhead cam (SOHC) engine
uses only one camshaft per cylinder head
Dual overhead cam (DOHC) engine
uses two camshafts per cylinder head
One operates the intake valves, while the other operates the exhaust
Animation Link

17. Type of Aspiration
Supercharger – Pump driven by crankshaft forces air into engine.
Turbocharger – Pump driven by exhaust gases forces air into engine.

18. Alternative Engines
Vehicles generally use internal combustion, 4-stroke cycle, reciprocating piston engines
Alternative engines include all other engine types that may be used to power a vehicle

19. Rotary Engine

20. Rotary Engine Operation

21. Used on some of the first automobiles
Steam Engine
Used on some of the first automobiles

22. Gas Turbine

23. Typical Automotive
Engines

24. Provides the lowest center of gravity of any piston engine
Horizontally Opposed
Provides the lowest center of gravity of any piston engine

25. Features four chain-driven camshafts and 32 valves
Overhead Cam V-8
Features four chain-driven camshafts and 32 valves

26. Inline SOHC
This 16-valve, four-cylinder engine has a belt-driven camshaft and a balance shaft

27. This engine uses many aluminum parts
Fuel-Injected V-8
This engine uses many aluminum parts

28. Each cylinder head contains two camshafts
DOHC V-6
Each cylinder head contains two camshafts

29. Note the reciprocating assembly and the valve train
V-8 Engine
Note the reciprocating assembly and the valve train

30. Six-cylinder engine with a rear drive belt for the injection pump
Inline Diesel
Six-cylinder engine with a rear drive belt for the injection pump

31. Two roller chains drive the overhead camshafts
V-12 Engine
Two roller chains drive the overhead camshafts

32. The End