Find how much heat the coolant will absorb to reach 93 °C. Using the total heat produced by burning 5.5 gallons of gasoline find the excess heat.
Since you only have so much room for your coolant, a system is also in place for that coolant to transfer heat energy to the air before cycling back to the engine. Suppose you only have 3.00 kg of coolant.
- Find how much heat the coolant will absorb to reach 93 °C.
- Using the total heat produced by burning 5.5 gallons of gasoline (see b above), find the excess heat that must be transferred to the air.
The formula for calculating specific heat capacity problems is Q = cm^T, where the Q is the amount of heat absorbed, c is the specific heat capacity of the substance, m is the mass of the substance, and ^T is the change in temperature. If we only have 3 kilograms of coolant, the amount of heat that amount would be able to handle, to maintain an internal motor temperature of 93 degrees Celsius, would be this:
Q = (.000003 MJ/g x C)(3000 g)(68 C)
Q = .612 MJ
In your previous question, we calculated 5.5 gallons of gasoline would produce 726 MJ of heat energy. So, if we subtract the .612 MJ from that, that would be the amount of heat energy needing to be transferred to air:
726 MJ - .612 MJ = 725.388 MJ, to be transferred to air. This is a lot of heat energy to be transferred, but it is a well-known fact internal combustion engines lose most of the heat produced to external surroundings. Most will exit the system through the vehicles exhaust system.