A radiator is a mechanical device which dissipates the heat produced in engine to the outside of an automobile. In automobiles, radiator with other devices makes a cooling system. The dissipation of heat is done by the fan. There are mainly two types of cooling systems in automobiles, air cooled system and water cooled system.
- Water cooled system
- The main source of heat is concentrated at the engine block and cylinder head. A required quantity of water is supplied around these parts to cool them.
- Water is pumped-up with the help of a pump. To circulate the water continuously around these parts, the pump is connected to the crankshaft by a pulley.
- Heat is carried by the water which are passed through the pipes. A radiator in the cooling system requires a constant rate of airflow through its core. When the automobile is running air flows through its core due to the velocity of the automobile.
- Application of fan
- When the automobile is in rest the constant rate is maintained by using a fan which dissipates the heat from the radiator.
- Fan used for this is driven by engine, so the fuel is wasted in this to run the fan separately by the engine. To overcome this some cars are fitted with viscous coupling operated by a temperature sensor valve that detaches the fan till it attains a set point.
- Some automobiles have an electric fan which is coupled by temperature sensor. It lets the engine warm up quickly and the radiator is enclosed by a thermostat, which is placed over the pump. Thermostat contains a valve worked by a section filled with wax.
- When engine gets the rated temperature, wax present in chamber melts and expands, which forces the valve to open allowing coolant through the radiator. When engine is cooled the valve closes again.
- An antifreeze is added to the water in the cooling system in order to prevent water from expanding when it heats. Ethylene glycol is added as an antifreeze with water.
- Air cooled system
- Air cooled system is a very simple system that uses fins on the cylinder head and cylinder block to dissipate from the engine.
- A duct runs on the fins, and a fan blows air through the duct to dissipate heat from the fins.
- Air flow by fan is controlled by a temperature sensor and maintains a constant temperature.
In water cooled and air cooled systems, a small radiator is attached which cools the engine oil of an automobile.
Radiator plays a major role in cooling system of an automobile and it uses a fan which controls the heat dissipation. As fans are used in both type of cooling systems, we can say that fans play an important role in automobile making.