Internal combustion (ic) engines. An internal combustion engine (ICE) is a heat engine where the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit.

1. Southern University Bangladesh
Course Title: Mechanical Engineering Fundamentals
Course Teacher: Ridoanur Rahaman
Prepared by:
Anowar Hossain Rana
Topic: Internal Combustion (IC) Engines
Department of Computer Science and Engineering (CSE)
cxranabd@gmail.com www.cxrana.com

2. INTRODUCTION
It is an engine in which combustion of fuel take place inside the engine. When the
fuel burns inside the engine cylinder, it generates a high temperature and pressure.
This high pressure force is exerted on the piston (A device which free to moves
inside the cylinder and transmit the pressure force to crank by use of connecting rod),
which used to rotate the wheels of vehicle. In these engines we can use only gases
and high volatile fuel like petrol, diesel. These engines are generally used in
automobile industries, generation of electric power etc.
In these engines there is a sequence of processes:
 compression
 combustion
 expansion
 exhaust / induction

4. There are two basic mechanical designs to achieve these four processes in
either:
four strokes of the piston - hence the 4-stroke engine, or
two strokes of the piston - hence 2-stroke engines.
Pictured here is an animation showing the basic
mechanics of how an internal combustion engine works.
Animated graphic by Sarah Gerrity

5. ADVANTAGES OF I.C. ENGINE
 It has overall high efficiency over E.C. engine.
 These engines are compact and required less space.
 Initial cost of I.C. engine is lower than E.C. engine.
 This engine easily starts in cold because of it uses high volatile fuel.

6. Types of I.C. Engine
According to number of stroke:
Two stroke engine
Four stroke engine
According to design of engine:
Piston engine
Rotary engine
According to design of engine:
Diesel engine
Petrol engine
Gas engine
Electric engine

7. According to method of ignition:
 Compression ignition engine
 Spark ignition engine
According to number of cylinder:
 Single cylinder engine
 Multi-cylinder engine
According to air intake process:
 Naturally aspirated
 Supercharged engine
 Turbocharged engine

8. APPLICATIONS OF IC ENGINES
I.C. engines have many applications, including:
 Road vehicles(e.g. scooter , motorcycle , buses etc.)
 Aircraft
 Motorboats
 Small machines, such as lawn mowers, chainsaws and portable engine-
generators

9. DIFFERENT PARTS OF I.C. ENGINE
Parts common to both diesel & petrol engine
 Cylinder
 Cylinder head
 Piston
 Piston Rings
 Connecting rod
 Crankshaft
 Crank
 Engine bearing
 Crankcase
 Flywheel
 Governor
 Valves
Parts common to Petrol engine only
 Spark plug
 Carburetor
Parts common to Diesel engine only
 Injector

11. COMPARISON CHARTS
2 Stroke Engine 4 Stroke Engine
Its piston makes two strokes in the engine Its piston makes four strokes in the engine
Loud Quieter
Less efficient, hence environmentally
unfriendly
Efficient, hence environmentally friendly
Relatively cheaper as they don’t have valves
Relatively expensive because of the
complexity of incorporating valves
Produce high power for a relatively short
period
Produce low power for a long period
The extra oil required to mix with fuel
makes them expensive to maintain
Doesn’t require oil in the fuel

12. Four Stroke

13. ENGINE PERFORMANCE
Efficiency:
Mechanical Efficiency = Brake Power (bhp)/ Engine Power (hp)
Thermal Efficiency = Engine Power (hp) / Fuel Power (hp)
Overall Efficiency = Mechancal x Thermal
An Engine is not 100% efficient (typical efficiency is about 30%). Because it
has some losses
Heat loss to cooling water 30%
Heat loss to exhaust gases 30%
Heat loss to lubricating oil 5%
Heat loss due to friction of mechanical
components
5%
Useful brake power available from
engine
30%
Total Heat Input to the engine 100%

14. THANK YOU ALL