Definition and types of engine with examples
Any device which can convert the heat energy of fuel into mechanical energy is known as engine or heat engine. It is basically a device that produces power. Engine is widely used in automobile industries and it is the heart of an automobile.
Classification of engine:
Engine may be classified into various types which are listed below:
Based on combustion of fuel:
(1) External combustion engine: Here, the working medium, the steam, is generated in a boiler, located outside the engine and allowed into the cylinder to operate the piston to do mechanical work.
(ii) Internal combustion engine: In internal combustion engine, the combustion of fuel takes place inside the engine cylinder and heat is generated within the cylinder.
According to fuel used:
(1) Diesel engine: These engines use diesel as the fuel. These are used in trucks, buses, cars, etc.
(2) Petrol engine These engines use petrol as fuel. These are used in bikes, sports cars, luxury cars, etc.
(3)Gas engine: These engines use CNG and LPG as the fuel. These are used in light motor vehicles.
(4)Electric engine: It is an eco-friendly engine. It doesn’t use any fuel to burn. It uses electric energy to rotate the wheel.
According to the ignition system:
(i) Spark ignition engine (Carburettor type engines): The mixture of air and fuel is drawn into the engine cylinder. Ignition of fuel is done by using a spark plug. The spark plug produces a spark and ignites the air-fuel mixture.
(ii) Compression ignition engine (injector type engines): In compression-ignition engines air is compressed into the engine cylinder. Due to this, the temperature of the compressed air rises to 700-900 C. At this stage diesel is sprayed into the cylinder in fine particles. Due to a very high temperature, the fuel gets ignited.
According to the stroke working cycle:
(i) Two-stroke engine: In a two-stroke engine, the crankshaft rotates one revolution in one time of
fuel burn.
(ii) Four-stroke engine: In four-stroke engine, the crankshaft rotates two revolutions in one time of fuel burn.
According to the number of cylinders:
(i) Single cylinder engine: Engine has only one cylinder and piston connected to the crankshaft.
(ii) Multi-cylinder engine: In this type of engine more than one cylinder and piston connected to the crankshaft.
According to the arrangement of the cylinder:
(i) In-line engine: Cylinders are positioned in a straight line one behind the other along the length of the crankshaft.
(ii) V-type engine: An engine with two cylinder banks inclined at an angle to each other and with one crankshaft known as a V-type engine.
(ii) Opposed cylinder engine: An engine with two cylinders banks opposite to each other on a single crankshaft (V-type engine with 180° angle between banks).
(iv) W-type engine: An engine same as V-type engine except with three banks of cylinders on the same crankshaft known
According to the cooling system:
(i) Water cooling
(ii) Air cooling
According to the design of the engine:
(i) Reciprocating engine (piston engine): In the reciprocating engine the pressure force generated by combustion exerted on the piston (A device which free to move in reciprocation inside the cylinder and it transmit the pressure force to the crankshaft by use of a connecting rod. So the crankshaft starts to rotate and rotates the wheel of the vehicle.
(ii) Rotary engine (Wankel engine): In a rotary engine, there is a rotor that is free to rotate. The pressure force generated by the burning of fuel is exerted on this rotor, so the rotor rotates and states to rotate the wheel of a vehicle.
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