Cooling is a necessary requirement of an I.C. Engine.
The combustion of air-fuel mixture generates 2500 degree centigrade temperature in the engine cylinder.
Cooling will remove the generated heat.
To withstand such a high temperature we have to use very high melting point material for construction of the engine.
Platinum, a metal which has one of the highest melting points, melts at above 1800 degree centigrade.
Practically, you can’t use this material due to many reasons.
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It has been practically found that out of total heat generated by internal combustion engine due to combustion of fuel; only 30% of heat is converted into useful work.
Out of remaining 70% about 40 % is carried by exhaust gases into the atmosphere during the exhaust stroke.
The suitable arrangement requires passing the rest of 30% into the atmosphere.
Why is Cooling required in Internal Combustion Engine?
In addition to overheating, large temperature differences may lead to distortion of the engine components due to set up of thermal stresses.
If the cooling system is not provided to an internal combustion engine, the lubricating oil film would break down and the lubricating oil will decompose to give gummy and carbon deposits.
In lack of cooling system, a complete seizure of the piston, bearing and other important parts will occur.
This requires more frequent replacements of the components.
It will also increase the repairing cost and breakdown period. It reduces engine life considerably.
The volumetric efficiency of the engine lowers with an increase in temperature.
This promotes pre-ignition and tendency of the engine to detonate.
Cooling can be achieved by Air or Water.
So, the two main properties desired of an efficient cooling system are,
01) It must be capable of removing only about 30% of the heat generated in the combustion chamber.
Too much heat removal will lower the thermal efficiency of the engine.
02) It should remove heat at a fast rate when the engine is hot.
It is also required to be very slow cooling at the starting of the engine so that the different working parts of the internal combustion engine reach their operating temperature in a short time period.
If you are using the water cooled engine, then are little chances of freezing of water in cold weather conditions.
It happens when we keep engine without use for very long time.
To overcome this problem, we have to mix anti freezers in cooling water.
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