As per the engines, the heat produced by the combustion of fuel in the engine cylinder is not converted into useful power at the crankshaft completely and the typical distribution of fuel energy is as follows:
If the heat is not removed from the cylinders, it would result in the pre-ignition of the charge.
The following are some reasons, why we need cooling systems in an Engine.
There are generally two types of Engine Cooling System are there, and those are the following:
The basic principle involved in this method is to have a current of air flowing continuously over the heated metal surface from where the heat is to be removed.
The heat dissipated depends upon the following factors:
The surface area of the metal which is in contact with the air should be increased for effective cooling and this can be done by using fins over the barrels.
These fins are either cast as an integral part of the cylinder finned barrels or inserted over the cylinder barrel.
Baffles are used sometimes to increase the contact area still further.
Because of their better thermal conductivity, the usage of copper and steel alloys has also been made to improve the heat transfer.
These are some advantages of Air Cooling System:
Also, there are some disadvantages of using Air Cooling System and those are:
The cooling medium used is "water" in the water cooling system.
In this, engine cylinders are surrounded by water jackets through which the cooling water flows. Heat flows from the cylinder walls into the water which goes to the radiator where it loses its heat to the air.
To avoid the frozen water in the engine during the winter season, antifreeze is added to the water.
By adding antifreeze, the water did not free and circulate through the system.
Note: Antifreeze + Water= Coolant
Usually, some antifreeze is added to the cooling water, due to which it is often referred to as coolant.
Water cooling systems are of two types :
It is a cooling system that works under Gravity.
The parts of the Thermosyphon Cooling System are:
A very simple system, which was used in many early automobiles is obsolete now. It consists of a radiator connected to the engine through flexible hoses.
In this system, the circulation of water is obtained from the difference in densities of the hot and the cold regions of cooling water.
The circulating water gets heat from the engine cylinders, thereby cooling the same.
The same heat in the water is then dissipated into the atmosphere, through the radiator, by mainly conduction and convection.
Therefore, the circulating water becomes cold by the time it reaches the collector tank of the radiator. The same water is then circulated through the engine to collect heat from the cylinders.
Some of the thermosyphon systems also had fans mounted behind the radiator and driven by belt and pulleys from the crankshaft, to assist the flow of cooling air.
The advantages of Thermosyphon Cooling System are as follows:
The disadvantages of Thermosyphon Cooling System are as follows:
It is a cooling system that works with a pump.
The Components of the Pump Circulation system are as follows.
This system is similar to the thermosyphon System described above with the only difference that a pump is used for the circulation of coolant and a thermostat is employed to control the flow of coolant. The pump is driven using a belt from the engine crankshaft.
The coolant is to be passed through the hose pipes and travel throughout the system. The thermostat plays a vital role in increasing the life of the radiator.
If the temperature of the coolant is less than 80°C, then the coolant does not enter into the radiator and it passes throughout the system with the help of bypass Pipe.
If the temperature of the coolant is more than 80°C, then the Thermostat valve opens and it sends the hot coolant into the radiator.
Now, the cooling fan is placed just before the radiator tubes and is attached to the crankshaft assembly to cool the coolant.
Due to the fan, the heat from the coolant is escaped from the tubes and after cooling the coolant, it is again underflowed through the hose pipe.
Here, the Centrifugal Pump is used to circulate the water throughout the system with high pressure so that the hot coolant cools at a faster rate.
In this way, the coolant will travels throughout the system and the hot gases do not affect the engine cylinders.
This is a detailed explanation of the Pump Circulation System in IC Engines. If you have any doubt, feel free to ask in the comments section.