Air cooling System:

In this type of cooling system, the heat, which is conducted to the outer parts of the engine, is radiated and conducted away by the stream of air, which is obtained from the atmosphere. In order to have efficient cooling by means of air, providing fins around the cylinder and cylinder head increases the contact area. The fins are metallic ridges, which are formed during the casting of the cylinder and cylinder head The amount of heat carried off by the air-cooling depends upon the following factors:

i) The total area of the fin surfaces,

ii) The velocity and amount of the cooling air and

iii) The temperature of the fins and of the cooling air.

Air-cooling is mostly tractors of less horsepower, motorcycles, scooters, small cars and small aircraft engines where the forward motion of the machine gives good velocity to cool the engine. Air cooling is also provided in some small industrial engines. In this system, individual cylinders are generally employed to provide ample cooling area by providing fins. A blower is used to provide air.

Advantages of air cooled engines:

i) Its design of air-cooled engine is simple.

ii) It is lighter in weight than water-cooled engines due to the absence of water jackets, radiators, circulating pump and the weight of the cooling water.

iii) It is cheaper to manufacture.

iv) It needs less care and maintenance.

v) This system of cooling is particularly advantageous where there are extreme climatic conditions in the arctic or where there is scarcity of water as in deserts.

vi) No risk of damage from frost, such as cracking of cylinder jackets or radiator water tubes