|PETROL (SPARK IGNITION) ENGINE||DIESEL (COMPRESSION IGNITION) ENGINE|
|Petrol engine works on Otto cycle.||Diesel engine works on Diesel cycle.|
|In petrol engine, a mixture of petrol and air is admitted into the cylinder during suction stroke with the help of carburetor.||Diesel is injected directly into combustion chamber at high pressure at the end of compression stroke.|
Carburetor is eliminated but high
pressure fuel pump and injector is
|Throttle valve in carburetor controls the quantity of mixture introduced in combustion chamber.||Quantity of fuel is regulated by fuel pump.|
|Petrol engine requires an ignition|
system with spark plug in combustion chamber.
|No spark plug is combustion of fuel is spontaneous due to very high pressure and temperature|
in combustion chamber.
|Compression ratio is about 6 to 10.5.||Compression ratio is about 14 to 22.|
|Higher r.p.m. due to lighter weight.||Maximum r.p.m. is lower.|
|Maximum efficiency is lower (about|
30 %) due to low compression ratio.
|Higher efficiency (about 40 %) due to higher compression ratio.|
|Engine can be easily startėd due to low compression ratio.||Engine cannot be started easily due to high compression ratio.|
|Petrol engine is lighter in weight.||Diesel engine is heavier due to higher pressure.|
|Petrol engines are generally employed in light duty vehicles like scooters, cars etc.||Diesel engines are generally employed in heavy vehicles like bus, truck etc.|
APPLICATION OF IC ENGINE
Four stroke petrol engine :
These engines are generally used in light vehicles such as passenger cars, scooters etc.
Two stroke petrol engine :
These engines are generally used in light vehicles such as scooters, motor cycles as it is light and compact.
Four stroke diesel engine :
These engines are generally used in heavy duty vehicles such as buses, trucks, tractors, pumping sets, diesel locomotives and in I.C. engine power plants etc.
Two stroke diesel engine :
These engines are generally employed in marine propulsion.