进气稀释策略是优化发动机性能的重要手段,针对稀释气体的热作用和稀释作用对发动机性能的影响展开了深入的研究。结果表明,热作用和稀释作用均使得缸内燃烧温度降低、放热率峰值降低、燃烧持续期变长、放热相位推迟，同时使NO_x 排放降低，但THC排放增大。热作用会使整机经济性恶化，而稀释作用则使整机经济性提高，稀释作用使经济性提高的主要原因在于其提高了工质的等熵指数。

The intake dilution strategy is an important method to optimize engine performance. The influences of diluted gas thermal and dilution effect on engine performance were deeply researched. The results show that both thermal and dilution effects result in the decrease of incylinder combustion temperature and peak heat release rate, the prolonging of combustion duration, the delay of heat release phase, the reduction of NO_x emission and the increase of THC emission. The thermal effect will deteriorate the engine economy, while the dilution effect will improve it due to the isentropic index increase of working substance.