Refrigerant charge is one of the most important factors affecting the performance of the transcritical CO₂ automotive air conditioning system. In the presented study, a transcritical CO₂ automotive air conditioning system test bench was set up, and the effect of normalized charge on the temperature, pressure and system performance were studied. A novel standard for judging the appropriate normalized charge was proposed. Meanwhile, the pressure-enthalpy diagrams under different charge was shown. Moreover, the influence of the ambient temperature and the compressor frequency on the charge characteristic were also experimentally studied and analyzed. Results revealed that the discharge temperature, the suction temperature and the temperature before the EXV were the optimal parameters to judge the charge characteristic. As the ambient temperature and compressor speed increased, the required charge amount decreased. It was concluded that the optimal normalized charge range of the transcritical CO₂ air-conditioning system was recommended to be set between 0.111 and 0.321. The results provide good guides in charge of automobile air conditioning system.

制冷剂充注是影响跨临界CO ₂汽车空调系统性能的最重要因素之一。在本研究中，跨临界CO ₂建立了汽车空调系统试验台，研究了归一化装料对温度，压力和系统性能的影响。提出了一种新的判断适当归一化电荷的标准。同时，给出了不同充量下的压焓图。此外，还通过实验研究和分析了环境温度和压缩机频率对充气特性的影响。结果表明，放电温度，吸入温度和EXV之前的温度是判断充电特性的最佳参数。随着环境温度和压缩机速度的增加，所需的充气量减少。结论是跨临界CO ₂的最佳归一化电荷范围建议将空调系统设置在0.111和0.321之间。结果为指导汽车空调系统提供了很好的指导。