The basic difference between diesel engine and petrol engine is that Diesel engine draws air during suction stroke, low-speed engine and costly than a petrol engine, while petrol engine draws a mixture of petrol and air and are high-speed engines.
Diesel Engine properties
- 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 is heavier and costlier.
- Starting of the diesel engine is difficult due to the high compression ratio.
- The maintenance cost of it is large.
- They are low-speed engines.
- They are generally employed in heavy-duty vehicles.
Petrol engines properties
- They are high-speed engines than diesel engines.
- They draw a mixture of petrol and air.
- The charge is ignited with plug.
- Starting of a petrol engine is easier than the diesel engine.
- They have a 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.