This study analyzed the thermal balance of a turbocharged gasoline direct injection engine with intake air humidification and studied the reason why intake air humidification improved the thermal efficiency of the basic engine. The results showed that since the evaporation of the introduced water absorbed heat in the intake port that caused the decrease of the temperature of the intake air, and the specific heat capacity of working medium increased with intake air humidification. Therefore, an apparent decrease in the in-cylinder temperature. Each energy loss can be affected by intake air humidification in different degrees, among which the exhaust loss and heat transfer loss decreased evidently, while pumping loss and friction loss increased to some extent. Furthermore, the sum of the decrease of exhaust loss and heat transfer loss was higher than the sum of the increase of pumping loss and friction loss, hence, the thermal efficiency of the basic gasoline engine increased when the benefit gained from intake air humidification was greater than the negative impact.

本研究分析了具有进气加湿功能的涡轮增压汽油直喷发动机的热平衡，并研究了进气加湿提高基本发动机的热效率的原因。结果表明，由于引入的水的蒸发吸收了进气口中的热量，从而导致进气温度降低，并且工作介质的比热随进气增湿而增加。因此，缸内温度明显降低。每种能量损失都会受到进气加湿的不同程度影响，其中排气损失和传热损失明显减少，而泵送损失和摩擦损失则有所增加。此外，