When the combustion of fuel takes place in cylinder of internal combustion engine, a very high temperature is developed. It is, therefore necessary to extract some of the heat from cylinder to atmosphere. It will avoid damage to the cylinder and piston. Heat also burns lubrication oil and form carbon. There is possibility of seizure of piston inside the cylinder, which will lead to more break down and repairing cost. To avoid this, cooling is necessary.
Air Cooling is mostly used in motorcycles, scooters where the forward motion of the machine gives a good velocity of air to cool the engine. Air Cooling is also provided in small industrial engines. In bigger unit a circulating fan is employed. But the fan absorbs 5% of the power developed by the engine.
Air Cooling is the simplest method in which the heat is carried out by the air flowing over and around the engine cylinder. In this system a current of air is Made to blow past the outside of cylinder barrel whose outer surface is area has been considerably increased by providing radiating fins. The cooling fins are arranged so that they are perpendicular to the axis of the cylinder.
In this system there is no such problem as corrosion or clogging of the radiator occurs, since there is no radiator is used (Radiator is used in water cooled Engines). There is also a complete absence of water freezing in cold weather conditions as in water-cooled engine.
Air Cooling is particularly advantageous where there are extreme climatic conditions as arctic or where there is lack of water as in deserts. It gives less Starting troubles.
Beside above advantages, this cooling system has some disadvantages also. Air-cooled engines on the average have limited size, non-uniform cooling and Higher working temperatures. They also produce more noise, gives a less petrol economy, lower maximum allowable compression ratio and lower output.
In next post, you will come to know about water-cooling of internal combustion engine.
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