PETROL ENGINE AND DIESEL ENGINE

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  The main difference between petrol and a diesel engine is the way they work and Use their fuels. What happens in a petrol engine is that at first the fuel is mixed with air, then piston compresses it and after compression it is ignited by spark plugs.

There is also a lot of difference between petrol and diesel engine and these are as follows:

• The petrol engine works on Otto cycle whereas diesel engine works on diesel cycle.
• In petrol engine the air and petrol are mixed in carburetor and it enters into the cylinder.
• In diesel engine the fuel is first fed into the cylinder by a fuel injector and then gets mixed with air inside the cylinder.
• In petrol engine first the compression of air and petrol is done and then it is ignited by an electric spark.
• In diesel engine only the charge of air is compressed and ignition is done by the heat of compressed air.
• The compression ratio in petrol engine is low as compared with the diesel engine.
• The power developed in petrol engine is low due to lower compression ratio.
• In diesel engine the power developed is more due to higher compression ratio.
• Petrol engine is fitted with spark plug whereas diesel engine is fitted with a fuel injector.
• In petrol engine the fuel that burns has high volatility. In diesel engine the fuel of less volatility is burnt.
• Petrol engines are used in light weight vehicles like car, motorcycles, scooters etc.
• Diesel engines are used in heavy vehicles like buses, trucks, locomotives etc.
• Fuel consumption in petrol engine is higher than the diesel engine.
• Petrol engine is lighter whereas diesel engine is heavier.
• Frequent overhauling is required in petrol engine but overhauling of diesel engine is done after a long time.
• There is lesser starting problem in petrol engine as compared with diesel engine.
• Petrol engine has lowered initial and maintenance cost but the initial and maintenance cost of diesel engine is high.

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  Gasoline (American English) or petrol (British English) is a transparent petroleum-derived liquid that is used primarily as a fuel in spark-ignited internal combustion engines.

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  Diesel fuel itself acts as a lubricant for the fuel pump and delivery system as well as the valve train. Running thin, low viscosity gasoline through a diesel fuel system would starve it for lubrication and cause those sensitive components to rub together, eventually destroying them.

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  The diesel engine (also known as a compression-ignition or CI engine), named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel, which is injected into the combustion chamber, is caused by the elevated temperature of the air in the cylinder due to the mechanical compression (adiabatic compression).

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  GASOLINE ENGINE  has an internal-combustion engine that burns gasoline; most automobiles are driven by gasoline engines.

• Chemical analysis and production. The bulk of a typical gasoline consists of a homogeneous mixture of small, relatively lightweight hydrocarbons with between 4 and 12 carbon atoms per molecule (commonly referred to as C4–C12). It is a mixture of paraffins ( alkanes ), olefins ( alkenes) and cycloalkanes (naphthene).

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  Fuel gas is any one of a number of fuels that under ordinary conditions are gaseous. Many fuel gases are composed of hydrocarbons (such as methane or propane), hydrogen, carbon monoxide, or mixtures thereof.

Difference Between Petrol and Diesel Engine in Tabular Form

S.No	Petrol Engine	Diesel Engine
1.	The petrol engine works on Otto cycle i.e. on constant volume.	The diesel engine works on diesel cycle i.e. on constant pressure.
2.	The air and petrol are mixed in the carburetor before they enter into the cylinder.	The fuel is fed into the cylinder by a fuel injector and is mixed with air inside the cylinder.
3.	The petrol engine compresses a mixture of air and petrol which is ignited by an electric spark.	The diesel engine compresses only a charge of air and ignition is done by the heat of compression.
4.	Compression ratio is low.	Compression ratio is higher in diesel engine.
5.	Less power is produced due to lower compression ratio.	Due to higher compression ratio more power is produced.
6.	Petrol engine is fitted with a spark plug	It is fitted with a fuel injector.
7.	Burns fuel that has high volatility.	Burns fuel that has low volatility.
8.	They are used in light vehicles which requires less power. Eg: car, jeep, motorcycle, scooters etc.	They are used in heavy vehicles which require high power. Eg: bushes, trucks, locomotive etc.
9.	Fuel consumption in petrol engine is high.	Fuel consumption in diesel engine is less.
10.	Lighter	Heavier
11.	Petrol engine requires frequent overhauling.	Overhauling of diesel engine is done after a long time.
12.	Lesser starting problem.	Greater starting problem.
13.	Lower initial cost.	Higher initial cost.
14.	Lower maintenance cost.	Higher maintenance cost.