Cooling system
Due to burning of fuel in combustion chamber of internal combustion engine, only 25% of heat is converted into mechanical energy out of total heat generated.
Loss of the energy passes through exhaust gases, cylinder walls is removed by means of cooling system of the engine.
Otherwise, it would result in the pre-ignition of the charge, burnt up of lubricant thereby scoring of cylinder, binding of pistons, bearing and warping of valve.
Too much cooling of the engine result in decreased thermal efficiency reduced fuel Vapourisation. so the temperature neither keeps the engine too hot nor too cold.
Purpose of cooling system
1) cools the engine and saves it from overheating.
2) Maintain normal temperature under all operating loads and speeds.
Types of Cooling system
There are two types of cooling system applicable in automobile engines. they are as under.
1) Air cooling system
2) Water cooling system
1) Air cooling system
The outer surface of the cylinders and cylinder heads. consists of fins which increase area of contact with the air.
By increasing the fins area, the air cooling will be more. By providing the fan, the mass of air flowing over the fins can be increased.
Merits
1) Power loss is saved better.
2) It is lighter .
3) Power loss is saved better.
4) Freezing and vapour of water are omitted.
5) In cooled countries, it gives better service.
6) Simple engines design resulting in low production cost.
7) Engine warms up more quickly.
8) Installation is easier.
Demerits
1) Such as system is suitable only for low horse power engine.
2) Non uniform cooling.
3) Heat transfer to air is only by conduction.
4) More noise.
5) Require fast riding.
6) Not suitable for multi cylinder engine.
2) Water cooling system
In this system the cooling water flows through the jackets made around the cylinder block, combustion chamber and valve ports.
The heat is absorbed from the cylinder. The radiator is used for storing cooling water which is circulated.
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