Various strokes are performed in internal combustion engine to get work done up to our requirement. To complete suction and exhaust stroke, there are some valves used which are known as suction valve and exhaust valve. Suction valve allow the fresh charge of air-fuel mixture inside the cylinder, where it is compressed and burnt by other parts. Due to combustion process large heat is developed and it makes exhaust valve very hot as burnt gases are escape from this valve to atmosphere.
As exhaust valve of an internal combustion engine is subjected to very high temperatures, it is therefore necessary to cool it down for the better performance of engine. Following ways can cool exhaust valve in,
01) By providing a suitable number of jets on the channel through which cold water directs from the radiator are pumped. The water flowing from these jets or nozzles in contact with the areas adjacent to the exhaust valve and exhaust port, which are thus cooled.
02) An improved Cooling can also be achieved if cooling jackets are provided more elaborately near exhaust valve and exhaust port.
03) By filling a part of the stem of the exhaust valve by sodium, we can achieve better Cooling. The solid melts at high temperature (Near about 750 degree centigrade) and is thrown up and down due to the motion of the exhaust valve. The heat from the hot region is thus conveyed to the comparatively cold region. Sodium is good conductor of heat and has a high boiling point. (750 degree centigrade)
It is more important to keep all the parts in workable limits for the better efficiency of the internal combustion engine. As a mechanical engineer, we have to take care of all our various machines and components.
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