1) External combustion Engine:
|Fig: External combustion Engine or EC Engine|
This is an engine in which the combustion or burning of fuel takes place outside of the cylinder. That’s why it is known as EC Engine. However, In this engine heat is obtained by burning of fuel, then it is used to convert the water or other low boiling temperature into steam. The steam is of high pressure and is used to rotate turbine. Fuels used in this engine may be solid, liquid or gas fuel . These types of engine are generally used to drive locomotive, ships, generation of electric power, also used in power plants,etc.
Advantages of External Combustion Engine:
- Higher Initial Torque.
- usability of cheap fuels like solid fuel.
- Flexibility as compared to IC Engine.
Disadvantages of External Combustion Engine:
- Engine takes more area i.e, Large size.
- It is heavy in weight.
- Combustion process takes long time.
2) Internal Combustion Engine:
|Fig: Internal Combustion Engine:|
This is an engine in which burning of fuel takes place inside the engine. That‘s why the name is Internal Combustion Engine. When the fuel burns inside the engine cylinder, it generates a high temperature and pressure.
This high pressure force is exerted on the piston (A device which free to moves inside the cylinder and transmit the pressure force to crank by use of connecting rod), which used to rotate the wheels of vehicle.
In these engines we can use only gases and high volatile fuel like petrol, diesel. Simple example: Automobile engine( Car and bikes,etc), generation of electric power, etc.
Advantages of Internal Combustion Engine:
- It has overall high efficiency over E.C. engine.
- These engines are compact and required less space.
- Initial cost of I.C. engine is lower than E.C. engine.
- This engine does not faces starting issues in cold because of it uses high volatile fuel.
- Combustion takes less time.
Disadvantages of Internal Combustion Engine:
- More complexity and less flexibility due to more moving parts in less space.
- Low power to weight and power to volume ratios.
- Can not use cheaper fuels eg solid fuels. However, only liquid or gaseous fuel of given specifications can be efficiently used. These fuels are relatively expensive.
- IC engines have reciprocating parts and hence balancing them is a problem and they are also susceptible to mechanical vibrations.
- High maintenance and lower combustion Efficiency.
- After a decade, the world may completely shift to electric vehicles due to increased pollution levels. Also statements regarding this are being made by several developed countries.