Difference between diesel and petrol engine

Diesel Engine:

• 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.

Petrol engines:

• 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.