- Diesel engine only draws air during suction stroke.
- The fuel is injected in the form of fine spray.
- Combustion of fuel takes place at constant pressure.
- The diesel engine are heavier and costlier.
- Starting of diesel engine is difficult due to high compression ratio.
- The maintenance cost of it is large.
- They are low speed engines.
- They are generally employed in heavy duty vehicles.
- They are high speed engines than diesel engines.
- They draw mixture of petrol and air.
- Charge is ignited with plug.
- Starting of petrol engine is more easier than diesel engine.
- They have low compression ratio.
- In petrol engines combustion of fuel take place at constant volume.
- They are generally employed in light duty vehicles.
- Running cost is high.