Internal Combustion Engine(IC Engine)

Any machine which derives heat energy from the combustion of fuel and coverts part of this energy into mechanical work is known as a heat engine. Heat engines are mainly divided into two groups, viz., external combustion engine and internal combustion engine.

In the case of external combustion engines, the combustion of fuel takes place outside the cylinder as in the case of steam engines. The other examples of external combustion engines are hot air engine, steam turbines and closed cycle gas turbines. In external combustion engines, first the heat of combustion is transferred to the working fluid outside the cylinder and then the fluid is expanded to develop the power.

The other types of engines, which are extensively used in practice, are internal combustion engines.

In internal combustion engines, the combustion of fuel in the presence of air takes place inside the cylinder and products of combustion directly act on piston to develop the power. The internal combustion engines are further classified as petrol engines, diesel engines and gas engines according to the type of fuel used.

These are commonly used for road vehicles, locomotives and several industrial applications. The maximum capacity of these engines is limited.

The internal combustion engines offer some special advantages over external combustion engines in smaller power ranges.

1. The thermal efficiency is high.

2. 'The horse power developed per unit weight of engine is high.

3. Starting is easy and quick.

4. It offers greater mechanical simplicity.

5. It requires less space.

6. The capital cost is low.