内燃机是将燃料的热能转变为机械能的原动机。燃料在内燃机气缸中所放出的总热量,只有40％左右能转变为机械功。其它部分均以不同的热传递方式最终散失于发动机之外,这部分散失的热量一般包括: (1)传递给冷却介质(如冷却水、冷却空气以及润滑油等)的热量Q_c; The internal combustion engine is a prime mover that converts the thermal energy of the fuel into mechanical energy. Only 40% of the total heat released by the fuel in the cylinder of the internal combustion engine can be converted into mechanical work. The other parts are ultimately lost in the engine by different heat transfer methods, this part of the heat loss include: (1) the heat transferred to the cooling medium (such as cooling water, cooling air and lubricating oil, etc.) Q_c;