Petrol Engine vs Diesel Engine : 12 X Difference Between Diesel Engine and Petrol Engine

Petrol Engine vs Diesel Engine How's Better? Petrol engine and diesel engine are the two types of engine being used till today. They are being categories based on the type of fuel they used for combustion.

Other than just there are multiple differences between these two engines and we developed a comprehensive comparison of both engines.

Petrol Engine vs Diesel Engine

Petrol Engine vs Diesel Engine 

We have developed a comprehensive 12 point difference between Diesel Engine vs Petrol Engine. This article will discuss following point for finding the diesel vs petrol engine differences.

• Suction Stroke
• Fuel Supply
• Pressure
• Fuel Ignition
• Working Cycle
• Compression Ratio
• Starting
• Weight Cost
• Thermal Efficiency
• Speed
• Cost 
• Application

Suction Strokes of Each Engine

First and biggest point in petrol engine vs diesel engine is the suction stroke of both engines. A mixture of air and fuel is drawn inside the combustion chamber of petrol engine while in the case of diesel engine only air is drawn in during suction stroke.

Fuel Supply of Diesel Engine vs Petrol Engine

Just like suction stroke the how fuel in supplied of each engine is a major point of diesel engine vs petrol engine comparison. 

In petrol engine carburetor is used to prepare the mixture of air and fuel and inject it into engine while fuel line in used in diesel engine which inject only a fine spray of fuel in engine at the end of compression stroke. 

Maximum Pressure Inside The Engine

At the end of compression stroke there is pressure on 10 bar in petrol engine and 35 bar in diesel engine

Fuel Ignition System of Engine

Petrol engine have a spark plug to ignite the air fuel mixture while in diesel engine highly compressed air have temperature about 600 degree C which is enough to ignite the fuel.

Working Cycle of Each Engine

Combustion of fuel in petrol engine happens at constant volume that is it work on OTTO cycle while in diesel engine combustion happens at constant pressure that means it work on Diesel cycle

Compression ratio of Diesel Engine vs Petrol Engine

Petrol engine small compression ratio of about 6 to 10 but diesel engine have high compression ratio of about 15 to 25

Starting of Petrol Engine vs Diesel Engine

Petrol engines are easy to start than diesel engine because less compression ratio

Weight of Both Engine

For higher compression heavy head is needed that’s why diesel engine are heavier than petrol engines

Cost of Engine

Due to light weight and cheap fuel petrol engines are cost effective than diesel engine and maintenance cost of petrol engine is also less than the diesel engine. 

Thermal efficiency of Diesel vs Petrol Engine

Comparing the thermal efficiency for diesel engine vs petrol engine shows that the thermal efficiency of petrol engine is about 26 % whereas thermal efficiency of diesel engine is about 40 %

Speed of Petrol vs Diesel Engine

Petrol engines are high speed engines and diesel  engines are low speed engines

Applications of Diesel Engine vs Petrol Engine

Last point in petrol engine vs diesel engine differences is the application of both engines. Light duty vehicles like motor bike and car have petrol engines whereas heavy duty vehicles have diesel engine.