why petrol engines have more power than diesel engines of same capacity?

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why petrol engines have more power than diesel engines of
same capacity?

Question Posted / balachandran

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why petrol engines have more power than diesel engines of same capacity?..

Answer / kiran

in petrol engines otto cycle is being used. for 2 cylinders
of same capacity (i.e same compression ratio) work done by
otto cycle is more than diesel cycle as the area bounded by
the otto cycle is more than diesel for same compression
ratio. but due to high pressure after compression in otto
cycles, its compression ratio is kept usually less so that
the maximum pressure is limited .

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why petrol engines have more power than diesel engines of same capacity?..

Answer / navas o t

friends...........
what is power.....? power is directly proportional to rpm, ie at lower rpm power is less. As diesel engine is concerned its rpm is limited because of smoke rejection(incomplete combustion in higher rpm's). so when we consider same capacity
engines petrol engine gives more rpm hence more power.

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why petrol engines have more power than diesel engines of same capacity?..

Answer / shantanu singh

friends...

in petrol engines we use carburator. which provides
homogeneous mixture of fuel & air. thus a good combustion.
but in diesel engine we have fuel injectors & the mixing of
air & fuel depends upon turbulence in the chamber. so not a
proper homogeneous mixture hence combustion is relatively
poor. power is directly related to rate of combustion.
hence petrol engines produce more power.

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why petrol engines have more power than diesel engines of same capacity?..

Answer / praveen

due to high calorific value of petrol.

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3 No

why petrol engines have more power than diesel engines of same capacity?..

Answer / dhamu

Guys!
I have read all ur ans but none of u said about compression ratio????????
for SI engine the CR = 7:1 to 14:1
for CI engine CR = 16:1 to 22:1
so basically very lean air fuel mixture is used for CI thats y diesel engine produces less power than petrol.

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why petrol engines have more power than diesel engines of same capacity?..

Answer / priya

In petrol engine there is pre mixing of fuel and air in carburetor that's y it has high speed.! then diesel

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why petrol engines have more power than diesel engines of same capacity?..

Answer / moosa alias mohasin

hi,
thre are two points

1 calorific value of petrol is more than diesel
2 compression ratio of petrol engine is less than diesel engine .so petrol engine need less power to work

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why petrol engines have more power than diesel engines of same capacity?..

Answer / valram faujdar

wrong question,deisel engine have more power than petrol due to its high compression ratio

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why petrol engines have more power than diesel engines of same capacity?..

Answer / kuldeep singh

i think this question itself is wrong, bcz diesel engine has more power than petrol engine of same capacity, bcz of the fact that compression ratio in diesel engine is more than the petrol engine. which results in greater release of power

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why petrol engines have more power than diesel engines of same capacity?..

Answer / arun shall

If capacity is same, the heat addition will be higher in
petrol engine due to constant volume heat addition
process,but heat rejection will be same for both,thus petrol
engine gives high power....its directly evident from pv
digram of otto and diesel cycles

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1 Yes

4 No