Internal Combustion Engine
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 1/43
Internal Combustion Engine
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 2/43
Engine
A device which produces power
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 3/43
Introduction
Combustion
A process to convert chemical energy
contained in the fuel into thermal energyEngine
A device which produces power
Heat Engine
A device which produces power from heat
energy which is produced from chemical energy
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 4/43
Classifications of Heat Engines
External Combustion (EC) Engine
The combustion takes place at out side the
cylinder.Eg: Steam engines
External Combustion (IC) Engine
The combustion takes place at inside the
cylinder.
Eg: petrol engines, Diesel engines
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 5/43
Classifications of IC Engines
Based on cycle of operations:
Two Stroke Cycle Engine
Four Stroke Cycle Engine
Based on cycle of combustion:
Otto Cycle
Diesel Cycle
Dual CycleBased on Number of cylinders:
Single cylinder engines
Multi cylinder engines
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 6/43
Classifications of IC Engines cont…
Based on arrangement of cylinders:
Horizontal Engine
Vertical Engine
V- type Engine
Radial type Engine
Based on fuel used:
Diesel Engine Petrol Engine
Gas engine
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 7/43
Classifications of IC Engines cont…
Based on speed:
Low speed Engines
Medium speed Engine
High speed Engine
Based on Method of ignitions:
Spark Ignition Engines
Compression Ignition EnginesBased on Method of Cooling:
Air Cooled Engines
Water Cooled Engines
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 8/43
Classifications of IC Engines cont…
Based on speed:
Low speed Engines
Medium speed Engine
High speed Engine
Based on Method of ignitions:
Spark Ignition Engines
Compression Ignition EnginesBased on Method of Cooling:
Air Cooled Engines
Water Cooled Engines
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 9/43
Classifications of IC Engines cont…
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 10/43
Parts of IC Engines
Parts common to both Petrol and Diesel engine:
1. cylinder 2. Cylinder head
3. Piston 4. Piston rings
5. Gudgeon pin 6. Connecting rod7. crankshaft 8. Crank
9. Engine bearing 10. Crank case
11. Flywheel 12. Governor
13. Valves and valve operating mechanism.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 11/43
Parts of IC Engines cont…
Parts for Petrol engines only:
1. Spark plugs
2. Carburetor
3. Fuel pump
Parts for Diesel engines only:
1. Fuel pump
2. Injector
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 12/43
Parts of IC Engines cont…
Cylinder:
where the piston moves up and down.
Hard grade cast iron.
Cylinder Head:
It placed at top of the cylinder to cover the
oneside of the cylinder.
Piston:
cylindrical piece of metal that moves up and
down the cylinder.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 13/43
Parts of IC Engines cont…
Piston rings:
It rounds the piston.
Cast iron.
Their main function is to provide a good sealing
fit between the piston and cylinder .
prevent fuel/air from leaking into the sump
prevent oil from entering the combustionchamber
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 14/43
Parts of IC Engines cont…
Combustion chamber:
Area where combustion and compression takes
place.
Connecting rod: It transmits the piston load to the crank to
convert the reciprocating motion of the piston
into rotary motion of the crankshaft.
Gudgeon pin
It supports and allows the connecting rod to
swivel.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 15/43
Parts of IC Engines cont…
Crankshaft:
It converts the reciprocating motion of the
piston into the rotary motion
Spark plug:
supplies spark for the fuel/air mixture.
Inlet Valves:
Admits the air or mixture of air and fuel intoengine cylinder.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 16/43
Parts of IC Engines cont…
Outlet Valves
Discharge the product of combustion.
Flywheel
In engine it takes care of fluctuations of speed
during thermodynamic cycle.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 17/43
Parts of IC Engines cont…
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 18/43
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 19/43
Terms connected with IC Engine
Bore:
Diameter of the cylinder or diameter of the
piston face
Top Dead Center (TDC):
The Maximum position of the piston inside the
cylinder
Bottom Dead Center (BDC): The Minimum position of the piston inside the
cylinder
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 20/43
Terms connected with IC Engine cont…
Clearance volume:
Minimum volume in the combustion chamber
with piston at TDC.
Stroke:
Amount of vertical travel of the piston from bottom dead
center (BDC) to top dead center (TDC)
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 21/43
Terms connected with IC Engine cont…
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 22/43
Four Strokes of an Engines
The four strokes are:
1. Suction Stroke
2. Compression Stroke
3. Power Stroke
4. Exhaust Stroke
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 23/43
Working of Four Stroke Diesel Engine
Suction Stroke:
Piston moves from TDC to BDC.
The inlet valve is opened.
The exhaust valve is remained closed for
entire stroke.
Vacuum is created inside the cylinder, so air is
entered into the cylinder. Where volume is increased and pressure is
reduced.
Flywheel completes half revolution.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 24/43
Working of Four Stroke Diesel Engine
Suction Stroke
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 25/43
Working of Four Stroke Diesel Engine
Compression Stroke:
Piston moves from BDC to TDC.
The inlet and exhaust valves are kept in
closed condition.
Now the air is compressed inside the cylinder
to high pressure and temperature.
At end of the compression stroke the fuel isinjected by fuel injector. The fuel is atomised.
Flywheel completes one revolution.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 26/43
Working of Four Stroke Diesel Engine
Compression Stroke
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 27/43
Working of Four Stroke Diesel Engine
Power Stroke:
Piston moves from TDC to BDC.
The inlet and exhaust valves are kept in
closed condition.
Fuel is burnt by the high temperature of air
and makes a downward thrust.
The high power is transmitted to crankshaftthrough connecting rod.
Flywheel completes one and half revolution.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 28/43
Working of Four Stroke Diesel Engine
Power Stroke
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 29/43
Working of Four Stroke Diesel Engine
Exhaust Stroke:
Piston moves from BDC to TDC.
The inlet is kept in closed condition and
exhaust valves is in opened condition.
The burnt gas is allowed to go out of the
cylinder due to upward movement of the
piston. Flywheel completes two revolution.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 30/43
Working of Four Stroke Diesel Engine
Exhaust Stroke
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 31/43
Working of Four Stroke Diesel Engine
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 32/43
Working of Four Stroke Petrol Engine
The four strokes are:
1. Suction Stroke
2. Compression Stroke
3. Power Stroke
4. Exhaust Stroke
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 33/43
Working of Four Stroke Petrol Engine
The working principle is similar that of Dieselengine.
Replace the words
Air by air fuel mixture &Fuel injector by spark plug
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 34/43
Working of Four Stroke Petrol Engine
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 35/43
Working of Two Stroke Petrol Engine
Suction Stroke:
Inlet port is in opened condition.
Transfer and Exhaust Ports are in closed
condition.
Piston moves from BDC to TDC
The fuel/air mixture is drawn into the
crankcase by the vacuum created during theupward stroke of the piston.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 36/43
Working of Two Stroke Petrol Engine
Suction
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 37/43
Working of Two Stroke Petrol Engine
Compression Stroke:
Inlet port is in opened condition.
Transfer and Exhaust Ports are in closed
condition. Piston moves from BDC to TDC
The piston compresses fuel/air mixture which
is at top of the piston. At the same time , another intake stroke is
happening beneath the piston
The crank completes half revolution of rotation.
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 38/43
Working of Two Stroke Petrol Engine
Compression
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 39/43
Working of Two Stroke Petrol Engine
Power Stroke:
Inlet port is also in closed condition.
Transfer and Exhaust Ports are in closed
condition.
Piston moves from TDC to BDC
At the top of the stroke the spark plug ignites
the fuel mixture. The burning fuel expands, driving the piston
downward
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 40/43
Working of Two Stroke Petrol Engine
Power
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 41/43
Working of Two Stroke Petrol Engine
Exhaust Stroke:
Inlet port is in closed condition.
Transfer and Exhaust Ports are in opened
condition.
Piston moves from TDC to BDC
the compressed fuel/air mixture in the
crankcase is allowed to enter into the maincylinder through transfer port.
This freshly entered air fuel mixture expels
the exhaust gasses out the exhaust port,
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 42/43
Working of Two Stroke Petrol Engine
Exhaust
7/28/2019 Basic Mecanical Ic Engines
http://slidepdf.com/reader/full/basic-mecanical-ic-engines 43/43