Difference Between Petrol and Diesel Engines

 

Difference Between Petrol and Diesel Engines

Both the diesel engine and the petrol engine are internal combustion engines. However, there are several differences between them, which are listed in the table below:

The Difference Based On	Petrol Engine	Diesel Engine
Definition	A petrol engine is an internal combustion engine that ignites the fuel using spark-ignition technology.	A diesel engine is an internal combustion engine that ignites the fuel using compression-ignition technology.
Working Cycle	The petrol engine operates on the Otto cycle.	The diesel engine operates on the diesel cycle.
Major Components	The engine cylinder, piston, spark plug, carburetor, and intake and exhaust valve are the essential components of a petrol engine.	The combustion chamber and cylinder, fuel injector, piston, intake, and exhaust valve are the essential components of a diesel engine.
Method of Ignition	The petrol engine uses an electric spark plug to generate an electric arc that ignites the fuel.	In a diesel engine, the high temperature of hot, compressed air ignites the fuel.
Air-fuel mixing	A carburetor is used in petrol engines to combine the fuel and air before introducing them to the engine cylinder.	The air and fuel are mixed inside the engine cylinder of a diesel engine. There is no carburetor in diesel engines.
Fuel volatility	Petrol engines run on highly volatile fuels such as petrol.	Diesel engines operate on low-volatility fuels.
Consumption of Fuel	Petrol engines require more fuel to generate the same amount of power.	Diesel engines use less fuel than other engines.
Engine Weight	A petrol engine is lightweight.	Diesel engines weigh a lot.
Starting Price	An initial investment in a petrol engine is lower.	A diesel engine is expensive to purchase new.
Maintenance	Regular maintenance is needed for petrol engines.	Less frequent maintenance is needed for diesel engines.
Cost of Maintenance	Petrol engines are inexpensive to maintain.	Diesel engines are expensive to maintain.
Power Produced	A petrol engine generates comparatively less power.	A diesel engine generates a lot of power.
Compression Ratio	A petrol engine has a relatively low compression ratio.	There is a high compression ratio in diesel engines.
Thermal Efficiency	A typical petrol engine has a thermal efficiency of about 26%.	A diesel engine has a thermal efficiency of about 40%.
Starting	Petrol engines have a low compression ratio, making them easy to start.	Due to its high compression ratio, diesel engines require a little more effort to start.
Speed	Petrol engines generally have high speeds.	Diesel engines generally have low speeds.
Noise & Vibrations	Petrol engines tend to be quieter and vibrate less.	Diesel engines are very noisy and vibrate a lot.
Environment-related Effects	Petrol engines produce relatively fewer environmental pollutants.	Diesel engines pollute the environment quite a bit.
Availability of Torque	The petrol engines have a limited amount of available torque.	Diesel engines have a comparatively high torque output.
Applications	Petrol engines are generally used in light vehicles like bikes, cars, etc.	Diesel engines are used in heavy vehicles like buses, trucks, trains, etc.

Wrapping It Up

Internal combustion engines are found in both petrol and diesel vehicles. Both engines have a four-stroke combustion cycle. However, they have different structures and roles. A diesel engine uses compression, while a petrol engine uses spark plugs.

It is clear that the examples provided above also differ in terms of their properties and functions. It is generally considered that gasoline vehicles are more affordable, quieter, and require fewer repairs and maintenance. Unlike gasoline-powered cars, diesel vehicles are more fuel-efficient and have a longer life cycle.

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