why cooling of ic engine requried.....??

               We know that in case of Internal Combustion engines, combustion of air and fuel takes
place inside the engine cylinder and hot gases are generated. The temperature of gases
will be around 2300-2500°C. This is a very high temperature and may result into burning
of oil film between the moving parts and may result into seizing or welding of the same.
So, this temperature must be reduced to about 150-200°C at which the engine will work
most efficiently. Too much cooling is also not desirable since it reduces the thermal
efficiency. So, the object of cooling system is to keep the engine running at its most
efficient operating temperature

.
              It is to be noted that the engine is quite inefficient when it is cold and hence the cooling
system is designed in such a way that it prevents cooling when the engine is warming up
and till it attains to maximum efficient operating temperature, then it starts cooling.
It is also to be noted that :
                    (a) About 20-25% of total heat generated is used for producing brake power
                         (useful work).
                    (b) Cooling system is designed to remove 30-35% of total heat.
                    (c) Remaining heat is lost in friction and carried away by exhaust gases.
                          Objectives

Heat engines generate mechanical power by extracting energy from heat flows, much as a water wheel extracts mechanical power from a flow of mass falling through a distance. Engines are inefficient, so more heat energy enters the engine than comes out as mechanical power; the difference is waste heat which must be removed. Internal combustion engines remove waste heat through cool intake air, hot exhaust gases, and explicit engine cooling.

Engines with higher efficiency have more energy leave as mechanical motion and less as waste heat. Some waste heat is essential: it guides heat through the engine, much as a water wheel works only if there is some exit velocity (energy) in the waste water to carry it away and make room for more water. Thus, all heat engines need cooling to operate.

Cooling is also needed because high temperatures damage engine materials and lubricants. Internal-combustion engines burn fuel hotter than the melting temperature of engine materials, and hot enough to set fire to lubricants. Engine cooling removes energy fast enough to keep temperatures low so the engine can survive.

Some high-efficiency engines run without explicit cooling and with only accidental heat loss, a design called adiabatic. For example, 10,000 mile-per-gallon "cars" for the Shell economy challenge are insulated, both to transfer as much energy as possible from hot gases to mechanical motion, and to reduce reheat losses when restarting^{[citation needed]}. Such engines can achieve high efficiency but compromise power output, duty cycle, engine weight, durability, and emissions.




It is important for an air-cooled engine to utilize fins for effective engine cooling to maintain uniform temperature in the 
cylinder periphery. Many experimental works has been done to improve the heat release of the cylinder and fin efficiency.  In 
this study, heat release of an IC engine cylinder cooling fins with six numbers of fins having pitch of 10 mm and 20 mm are 
calculated numerically using commercially available CFD tool Ansys Fluent. The IC engine is initially at 150  and the heat 
release from the cylinder is analyzed at a wind velocity of 0 km/h. The heat release from the cylinder which is calculated 
numerically is validated with the experimental results. With the help of the available numerically results, the design of the I.C 
engine cooling fins can be modified for improving the heat release and efficiency. 







         

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