ENGINE :
The term engine is associated with generation of power with help of some mechanism. Various mechanisms are associated in a single unit of different units to get useful work or power. Thus, engine is a very broad term.
Mainly, the engines are classified in to two categories according to the combustion process.
- External Combustion Engine.
- Internal Combustion Engine
EXTERNAL COMBUSTION ENGINES :
In an external combustion engine (E.C. Engine) the combustion of fuel takes place in different unit or section and the power is generated in other unit or section. External combustion engines are generally used in power plants for generation electricity. For example , consider a power plant generating electricity with the help of coal. Here, the combustion of fuel takes place in firing chamber and with help of this energy water is converted in to steam or vapour. This steam or vapour is transferred to other unit of plant with help of pipes and then imparted on turbine vanes. The turbine rotates and we get mechanical work as output which is further used to generate electricity. Thus, combustion process is occurred in combustion chamber and the power is generated in unit where the turbine is located. So External Combustion Engines are relatively larger in size in comparison with Internal Combustion Engines.
INTERNAL COMBUSTION ENGINES :
In Internal Combustion Engines (I.C. Engine) the power is generated in the same unit or section where the combustion takes place. So Internal Combustion engines are widely used in Automotive applications. The mechanism used to generate power is different than external combustion engines. For example, in four stroke gasoline engine the power is generated in by association of suction stroke, compression stroke, expansion stroke and exhaust stroke respectively. Internal Combustion Engines are relatively smaller than External Combustion Engines so they are most convenient to be used for mobile application such as Automotive.
