7/21/2019 2stroke Petrol & Diesel Engine

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  Malwa Institute of Science & Technology, Indore

Experiment No. 2

Aim: Study of two stroke petrol & diesel engine.

Apparatus required: Model of cross section of 2 stroke petrol engine.

Working:  In two stroke engines, the inlet, transfer & exhausted ports are covered &

uncovered by moving piston. he following operation takes place in two strokes or in one cycle o

the engine.

(1)  Charge transfer & sa!enging:

!hen piston is nearer to crankshaft "#$%, the transfer port is uncovered by piston. '

mixture of air & fuel "in case of petrol engine (air "in case of diesel engine as a charge,

slightly compressed in the crank)case, enters through the transfer port & drives out the

 burnt gases of the previous cycle through the exhaust port. In two stroke engine, the piston

is made deflected. herefore, the incoming charge is directed upward, aid in sweeping of

the burnt gases out of the cylinder. his operation is known as scavenging.

(2) Compression & sution:

's piston moves upward, both transfer port & exhausted port are covered by piston & the charge

"in case of petrol engine (air "in case of diesel engine trapped in the cylinder is compressed by

the pistons upward movement. 't the same time, the partial vacuum is created into crank)case, thsuction port open by moving crank & the fresh charge enters the crank)case.

(")Com#ustion & po$er:

 Petrol Engine: !hen the piston reaches at its end of stroke nearer to cylinder head or at

$%, a high intensity spark plug ignites the charge & initiates the combustion in the

cylinder. he burning of charge generates the pressure in the cylinder.

 Diesel Engine: !hen the piston reaches at its end of stroke nearer to cylinder head or at

$%, the fuel in*ector in*ects the fuel on the hot compressed air & initiates the combustion

in the cylinder. he burning of charge generates the pressure in the cylinder. 

7/21/2019 2stroke Petrol & Diesel Engine

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  Malwa Institute of Science & Technology, Indore

(%) Exhaust:

's piston descends through about +- of the expansion stroke, the exhaust port is

uncovered by piston, & the combustion gases leave the cylinder by pressure difference & a

the same time, underside of piston causes compression of charge taken in to crank)case.

Appiation:

a 2 stroke engine are used, where simplicity & low cost is main considerations.

 b cc)/cc engines are used in mopeds.

c 0cc)0cc engines are used in scooters & bikes.

d 'lso used in small electric generator sets.