How much heat is utilized to produce brake power from the total heat generated in combustion chamber?

How much amount of heat is utilized to produce brake power from the total heat generated in combustion chamber?

Options:

a. 50-60%
b. 20-25%
c. 80-85%
d. 5-10%

Correct Answer: b. 20-25%

Explanation:

In internal combustion engines, the temperature of gases produced due to combustion is around 2000-2500 0C. This high temperature can burn the lubrication oil in the cylinder and may also damage the weldings of the engine. Thus to reduce this temperature to an optimum temperature, the engine cooling system is provided. I C engines can work more efficiently at 100-150 0C. Thus the cooling system maintains the temperature of I C engine around 100-150 0C. So the 30-35% of total heat generated in combustion chamber is removed by cooling system and 50-60% of total heat is carried away by exhaust gases. Therefore, only 20-25% of total heat is generated is used to produce brake power that is useful work.