Answer / prasad

In case of diesel engine,
1. calorific value is less,
2. diesel engine utilises power for itself for pumping and
compressing fluid whereas in case of petrol engines spark
is produce to burn the charge so that reduces the power
loss.

Answer / balachandran

my friend the question u have asked is not complete .A petrol and diesel engine should be compared for a given parameter ,other wise how we can compare?.any way I am assuming that for same capacity.suppose consider a 1000CC petrol and diesel engine.Usually petrol will have more power becz,petrol engine produces more heat at the combustion chamber as petrol having more calorific value .moreover heat losses will be more in the cases of diesel engine than petrol engine such as compresion losses,turbulent loses,exhaust loses...Any way even though the compression ratio is high for diesel engine it wont contribute to increased power ,but an increased torque,thats why diesel engines have high torque than petrol engines for same capacity,still dobt existing mail me at bala300587@gmail.com

Answer / ravi gupta

actually per kg petrol has higher calorific value than
diesel ...so it produces greater heat energy ...the heat
produced by diesel engine goes mostly in the form of torque
due to larger
length of stoke ...whereas a petrol engine produces more rvs
than torque...therefore we usually say that a petrol engine
has higher power than diesel engine..also as losses are more
in a diesel engine like compression losses which are absent
in petrol engine..

Answer / lokesh

A petrol engine revs higher, which allows it to burn more fuel and output more power.

Answer / kashif haider naqvi

yes balachdran is right although diesel engine has high
compression ratio, its responsbility is to produce only
torque.
followiing things are responsible:
ignition by spark plug
comparatiively less loses
uniform burning.


kahf haider naqvi
WEC,PAK.

Answer / manju.m

Check the Calorific Value of both the fuel, you will get
the answere,...

Diesel has more calorific value than petrol

Answer / bejoy

sorry guys i won't agree to u guys...
i would say the question itslef is incomplete as normally
diesel engine is more efficient than a petrol
engine(surprise!!??)

yes..diesle engines do require a lot of maintenance due to
its his vibration and operating temperature etc.. if not
maintained the efficiency goes well below that of a petrol
engine..
at same cc.. a diesel engine has more efficiency..infact its
efficiency can be made a lot better still by adding
turbochargers annd VVT and using CRDi etc..

the reason is that in diesel engines better combustion
occurs(higher compression+more air)..
take care..

Answer / manju.m

Its a pretty simple question,...
as you know the calorific value of Petrol and Diesel (34.8
MJ/L and 38.6 MJ/L)

burning diesel will give you more energy than petrol,...
more energy means more power,

check the calorific value of petrol and diesel, that will
give you the ans for your question

Answer / rakesh tomar

Although there is more compression ratio in diesel engine
but
1.there is non uniform burning of air fuel mixture
2.Less turbulance in engine
3.less energy extracted by diesel than petrol

Answer / saravanan

diesel engine having less self ignition temperature compared
to petrol engine hence the diesel engine having more
compression ratio because ignited so that's why
compression ratio is high compared to petrol engine

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