The document discusses internal combustion engines. It classifies internal combustion engines in 9 ways: by fuel type (petrol, diesel, gas), ignition type (spark, compression), number of strokes (2, 4), operating cycle (Otto, diesel, dual), speed (slow, medium, high), cooling system (air, water, evaporative), fuel injection method (carburetor, air, solid), number of cylinders (single, multi), and cylinder arrangement (vertical, horizontal, radial, in-line, V-type, opposite, opposite-piston). It also discusses the main components, cycles, and diagrams of 2-stroke and 4-stroke engines.

1. Internal Combustion Engines
The internal combustion engines are those
engines in which the combustion of fuel takes
place inside the engine cylinder. It is known as
IC engines.

2. Classification of IC Engines
1. According to the type of fuel used
(a) Petrol engines
(b) Diesel engines
(c) Gas engines
2. According to the method of igniting the fuel
(a) Spark ignition(SI) engines
(b) Compression ignition(CI) engines
(c) Hot spot ignition engines

3. Classification of IC Engines
3. According to the number of strokes per cycle
(a) Two stroke cycle engines
(b) Four stroke cycle engines
4. According to the cycle of operation
(a) Otto cycle engines
(b) Diesel cycle engines
(c) Dual combustion cycle engines

4. Classification of IC Engines
5. According to the speed of the engine
(a) Slow speed engines
(b) Medium speed engines
(c) High speed engines
6. According to the cooling system
(a) Air-cooled engines
(b) Water-cooled engines
(c) Evaporative cooling engines

5. Classification of IC Engines
7. According to the method of fuel injection
(a) Carburetor engines
(b) Air injection engines
(c) Solid injection engines
8. According to the number of cylinders
(a) Single cylinder engines
(b) Multi-cylinder engines

6. Classification of IC Engines
9. According to the arrangement of cylinders
(a) Vertical engines
(b) Horizontal engines
(c) Radial engines
(d) In-line multi-cylinder engines
(e) V-type multi-cylinder engines
(f) Opposite-cylinder engines
(g) Opposite-piston engines

7. Main components of IC Engines

8. 4-stroke engine

9. Theoretical and actual valve Timing diagram for 4-stroke
petrol engine

10. Actual valve Timing diagram for 4-stroke petrol
engine

11. Four-stroke cycle petrol engine

12. Actual indicator diagram for a
four-stroke cycle petrol engine

14. Four-stroke cycle diesel engine

15. Actual indicator diagram for a four-
stroke cycle diesel engine

16. 2-stroke engine

17. Two-stroke cycle diesel engine

18. Actual indicator diagram a two-stroke
cycle diesel engine

19. Two-stroke cycle petrol engine

20. Actual indicator diagram a two-stroke
cycle petrol engine

21. Advantages and disadvantages of
two-stroke over four-stroke cycle
engines