Heat is generated in the I C engine due to combustion of fuel and rubbing of reciprocating parts, This heat needs to be removed from the engine to work the engine normally . If this heat is not removed the engine will cease to work ,because the molecules of the metal expands when heated , expand molecules increases friction between parts and over expansion of molecules results in struck of engine parts. Thus there is need of a system to remove excess heat from engine and maintain an optimum working temperature.
The engine cooling system works on the principle of second law of thermodynamic i.e heat transfer from a body of higher temperature to a body of lower temperature. The heat transfers in three mediums Conduction, convection , radiation.
When heat is exchanged between two metal bodies in contact it is conduction.
When a liquid is used as a medium of heat transfer this system is termed as convection. When air is used as a medium of heat transfer it is known as radiation.
the heat generated inside the IC engine is converted into work and an amount of heat is carried out by exhaust gases, to remove the left over heat a cooling system is required.
Currently there are two types of cooling systems used in automobile engines viz.
1. Air cooled.
2.liquid cooled.
Air cooled engine.
The air cooled system is ideal for single cylinder or v twin engine .In air cooled engine the atmospheric air carries away the heat generated by engine , The air acts as a medium of heat transfer in this types of engines.
Anti corrosion agent.
The engine cooling system works on the principle of second law of thermodynamic i.e heat transfer from a body of higher temperature to a body of lower temperature. The heat transfers in three mediums Conduction, convection , radiation.
When heat is exchanged between two metal bodies in contact it is conduction.
When a liquid is used as a medium of heat transfer this system is termed as convection. When air is used as a medium of heat transfer it is known as radiation.
the heat generated inside the IC engine is converted into work and an amount of heat is carried out by exhaust gases, to remove the left over heat a cooling system is required.
Currently there are two types of cooling systems used in automobile engines viz.
1. Air cooled.
2.liquid cooled.
Air cooled engine.
The air cooled system is ideal for single cylinder or v twin engine .In air cooled engine the atmospheric air carries away the heat generated by engine , The air acts as a medium of heat transfer in this types of engines.
Cooling fins are attached to engine block to enhance the cooling process, the cold atmospheric
air touches the cooling fins and carries away the heat waves (as shown in the above picture).
Limitations of air cooling system
The air cooled system can only be used in single cylinder or v twin engine of two wheeler only, because the air can't reach all the cylinder walls of multi cylinder engine. In cars there is no
enough contact of engine to the atmospheric air, Thus air cooling system is not suitable here.
Liquid cooled engine
In Liquid cooled engine a liquid (Water) is used to carry away the heat from engine.
In water cooled engine water is used as a medium to carry away the heat from engine.
The engine block has water ports or water jackets through which the cooling water passes.
additives in cooling water
The water alone is not sufficient for the engine cooling due to the following reasons.
- In cool weather areas the cooling water may get freeze.
- Water starts boiling and evaporates due to high engine temperature, .
- Water can corrode the engine parts.
- Anti freezing agent.
- Anti corrosion agent.
To lower the freezing temperature of cooling water an anti freezing agent is added, generally
Ethylene glycol is used as anti freezing agent. Ethylene glycol not only lowers the freezing point of
water, it also raises the boiling point of water.
To protect the metal parts of engine from corrosion, an anti corrosive agent is added in the coolant, generally silicates are added as anti corrosion agent.
The engine coolant is a composition of water , anti freezing agent and anti corrosion agent.
Working system
The cooling system consist of the following parts.
- Water jackets.
- Thermostat valve.
- Radiator.
- Radiator cap(pressure cap)
- Coolant tank.
- Cooling fan.
- Water pump.
after absorbing the heat the water becomes hot , the hot water is send to radiator for cooling. The
cooling fan cools the water in the radiator. Water pump is used to pump the cool water inside the engine.
The rest of the system will be explained in my next post please submit your mail id in the top box to get update about my new post. .
