Petrol Engines OK

8/14/2019 Petrol Engines OK

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PETROL ENGINES


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PETROL ENGINES

Most engines use a fuel as their energy

store.The fuel is burnt to produce heat energy,which is

then converted into movement

What is an engine?It is a device for convert ing sto red energy

into usefu l work or movement.


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CLASSIFICATION OF ENGINES

Engines can be classified according to thefuel they use

ETROL ENGINES DIESEL ENGINE


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CLASSIFICATION OF ENGINES (Contd..)

Engines can also be classified according to

whether the fuel is burnt inside or outside the

engine

INTERNAL

COMBUSTION ENGINES

EXTERNALENGINES

(Steam Engine)


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engine

INTERNAL

COMBUSTION ENGINES

EXTERNALENGINES

(Steam Engine)


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engine

INTERNAL

COMBUSTION ENGINES

EXTERNALENGINES

(Steam Engine)


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TYPES OF PETROL ENGINES

7.Number of strokes used.

1.Number of cylinders

2.Cylinder arrangements

The Petrol engines may be classified according to

3.Valve arrangements

4.Speed of the engines

5.Cooling system

6.Lubrication system used


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HORIZONTAL ENGINE


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VERTICAL CYLINDER FOUR STROKE ENGINE


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VERTICAL CYLINDER TWO STROKE ENGINE


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14/61V TYPE STIRLING ENGINES


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SIX CYLINDER ENGINE


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ROTARY ENGINE


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WANKEL ENGINE/ROTARY ENGINE


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FOUR CYLINDER ENGINE

H i t ll d i


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Horizontally opposed engine


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RADIAL ENGINE


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INLET PORT

EXHAUST PORT

TRANSFER PORT

CYLINDER

SPARK PLUG


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TWO STROKE ENGINES

In this type of engines the cycle is completed in

two strokes.When the piston moves from B.D.C toT.D.C, the air and fuel mixture is taken inside the

crank case.

T D C position B D C position


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T D C

B D C

Strokeis the distance of the piston travels

from BDC to TDC

STROKE

This measurements are used to figure

the piston displacement

stroke


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When the piston moves from T.D.C to B.D.C the inlet

port is closed, the mixture is compressed and

transferred the into the cylinder through transfer port.

Inlet portexhaust port

piston

Transfer port


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When the piston moves from T.D.C to B.D.C the inlet

port is closed, the mixture is compressed and

transferred the into the cylinder through transfer port.


piston

Transfer port


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When the piston is moving upward ,the mixture is

compressed.

At the same time,air and fuel mixture is coming into the

crankcase.


Transfer port

NO FUEL MIXTURE AVAILABLE


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Compressed mixture

When the piston is moving upward ,the mixture is

compressed.

At the same time,air and fuel mixture is coming into the

crankcase.


Transfer port


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At the end of the compression stroke, a spark is

given by a spark plug.The fuel mixture expands

rapidly.A high power is produced. This powerforces the piston downwards.So the piston moves

from T.D.C to B.D.C

Burning the fuel mixture


Transfer port


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When the piston comes down, the exhaust port opens

and exhaust gases are going out.At the same time,the

transfer port also opens and the fresh mixture comesinside the cylinder

Thus the four strokes are completed in two strokes of the engine


Transfer port


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When the piston comes down, the exhaust port opens

and exhaust gases are going out.At the same time,the

transfer port also opens and the fresh mixture comesinside the cylinder

Thus the four strokes are completed in two strokes of the engine


Transfer port

exhaust port

Transfer port


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ADVANTAGES OF TWO STROKE ENGINES

1.Simple in construction

2.Easy to manufacture

3.Low cost

4.Simple lubrication system

5.Uniform power production

(one power stroke for every revolution of the crank shaft)

6.There is no separate valve operating mechanism

7.More power is produced


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DISADVANTAGES OF TWO STROKE PETROL ENGINES

1.It consumes more lubrication oil

2.Wear and tear more

3 Not suitable for heavy duty engines

4.More wastage (unburnt fuel may escape through port)

5.The dead gases can not be removed completely


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FOUR STROKE ENGINES


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Fig.

IN LET VALVE

OPEN POSITIONEXHAUST VALVE

CLOSE POSITION

FOUR STROKE ENGINES

FIRST STROKESUCTION STROKE

While the inlet valve is open ,the descending piston draws freshpetrol and air mixture into the cylinder.

FOUR STROKE ENGINES


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Fig.

IN LET VALVE


CLOSE POSITION

FOUR STROKE ENGINES



FOUR STROKE ENGINES


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Fig.

IN LET VALVE


CLOSE POSITION

FOUR STROKE ENGINES



FOUR STROKE ENGINES


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Fig.

IN LET VALVE


CLOSE POSITION

FOUR STROKE ENGINES




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SECOND STROKE-COMPRESSION STROKE

While the valves are closed,the rising piston

compresses the mixture to a pressure about 7-8atm;

the mixture is then ignited by the spark plug.

Fig.

IN LET VALVE

CLOSE POSITION

EXHAUST VALVE

CLOSE POSITION


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Fig.

IN LET VALVE

CLOSE POSITION

EXHAUST VALVE

CLOSE POSITION






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Fig.

IN LET VALVE

CLOSE POSITION

EXHAUST VALVE

CLOSE POSITION






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Fig.

IN LET VALVE

CLOSE POSITION

EXHAUST VALVE

CLOSE POSITION





THIRD STROKE POWER STROKE


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THIRD STROKE-POWER STROKE

While the valves are closed the pressure of the

burned gases of the combustion forces push thepiston downwards.

Fig.

IN LET VALVE

CLOSE POSITIONEXHAUST VALVE

OPEN POSITION


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FOURTH STROKE-EXHAUST STROKE

The exhaust valve is open and the rising

piston discharges the spent gases from thecylinder.

Fig.


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SUCTION STROKE


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COMPRESSION STROKE


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POWER STROKE


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1.Less fuel consumption

2.Thermal efficiency is more

ADVANTAGES OF FOUR STROKE ENGINES

3.More volumetric efficiency

4.Less wear and tear.


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DISADVANTAGES OF FOUR STROKE ENGINES

4.More complicated design.

1.More components

2.Separate valve operating mechanism is required.

3.More cost


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PISTON ARRANGEMENT IN TWIN CYLINDER ENGINE

CRANK SHAFTCONNECTING ROD


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PISTON ARRANGEMENT IN FOUR CYLINDER ENGINE


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PISTON ARRANGEMENT IN FIVE CYLINDER ENGINE


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PISTONPISTON RINGS

ISTON PIN BOSS

PISTON SKIRT

PISTON TOP

RING GROOVES

FIRE RING


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CYLINDER,PISTON, SPARK PLUG AND

VALVES ARRANGEMENT

Petrol Engines OK

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