Fuel is burnt inside the cylinder of an indoor combustion engine to supply power. The temperature produced on the facility stroke of an engine are often as high as 1600 ºC and this is often greater than freezing point of engine parts.. The best operating temperature of IC engines lie between 140 F and 200 ºF and hence cooling of an IC engine is very essential. . It is estimated that about 40% of heat content produced is passed to atmosphere via exhaust, 30% is removed by cooling and about 30% is employed to supply power.


1. To maintain optimum temperature of engine for efficient operation under all conditions.
2. To dissipate surplus heat for cover of engine components like cylinder, plate , piston, piston rings, and valves 3. To maintain the lubricating property of oil inside engine.
Methods of Cooling
1. Air cooled system
2. Water cooled system

                                         Air cooled engines are those engines during which heat is conducted from the working components of the engine to the atmosphere directly.
Principle of air cooling- The cylinder of an air cooled engine has fins to extend the world of contact of air for quick cooling. The cylinder is generally enclosed during a sheet casing called cowling. The fly wheel has blades projecting from its face, in order that it acts sort of a fan drawing air through a hole within the cowling and directed it round the finned cylinder. For maintenance of air cooled system, passage of air is kept clean by removing grasses etc. by a stiff brush of compressed air.
Advantages of Air Cooled Engine :
1. It is simple in design and construction
2. Water jackets, radiators, pump , thermostat, pipes, hoses aren't required.
3. It is more compact
4. Lighter in weight

1. There is uneven cooling of engine parts
2. Engine temperature is usually high during working period Air cooled engine
Engines using water as cooling medium are called water cooled engines. Water is circulated around the cylinders to soak up heat from the cylinder walls. The heated water is conducted through a radiator to get rid of the warmth and funky the water.
Methods of Water Cooling :
1. Open jacket or hopper method
2. Thermo siphon method
3. Forced circulation method
1. Open Jacket Method
There is a hopper or jacket containing water which surrounds the engine cylinder. Solong because the hopper contains water the engine continues to work satisfactorily. As soon because the water starts boiling it's replaced by cold water.. The hopper is large enough to run several hours without refilling. A drain plug is provided during a low accessible position for draining water as and when required.
2. Thermo Siphon Method :
It consists of a radiator, vessel , fan, temperature gauge and hose connections. The system is predicated on the principle that heated water which surrounds the cylinder becomes lighter and it rises upwards in liquid column. Hot water goes to the radiator where it passes through tubes surrounded by air. Circulation of water takes place thanks to the rationale that vessel and radiator are connected at each side i.e. at top and bottom. A fan is driven with the assistance of a V belt to suck air through tubes of the radiator unit, cooling radiator water. The disadvantage of the system is that circulation of water is greatly reduced by
accumulation of scale or foreign matter within the passage and consequently causing overheating of the engine.
3. Forced Circulation System :
In this method, a pump is employed to force water from radiator to the vessel of the engine. After circulating the whole run of vessel , water comes back to the radiatorwhere it loses its heat by the method of radiation. To maintain the right engine temperature, a thermostat valve is placed at the outer end of plate . Cooling liquid isby-passed through the vessel of th3e engine until the engine attains the specified temperature. The thermostat valve opens and therefore the by-pass is closed, allowing the water togo to the radiator. The system consists of the following components :
1. Water pump
2. Radiator
3. Fan
4. Fan-belt
5. Water jacket
6. Thermostat valve
7. Temperature gauge
7. Hose pipe
Water Pump :
It is a centrifugal pump. It draws the cooled water from bottom of the radiator and delivers it to the water jackets surrounding the engine.
Thermostat Valve :
It is an impact valve utilized in cooling system to regulate the flow of water when activated by a temperature signal.
The fan is mounted on the pump shaft. It is driven by an equivalent belt that drives the pump and dynamo. The purpose of radiator is to supply strong draft of air through the radiator to enhance engine cooling
Water jacket :
Water jackets are passages cored out round the engine cylinder also as round the valve opening Forced Circulation cooling system.
We hope that you will get some helpful knowledge about FUNCTION COOLING SYSTEM.