重型商用车怠速与爬坡工况对空调制冷性能的影响

Research on Air-Conditioning Refrigeration Performance of Heavy Commercial Vehicles Under Idling and Climbing Conditions

重型商用车空调系统的制冷性能受到具体行车工况以及发动机舱布置的严重制约。基于Star CCM+与AMESim分别建立了某重型商用车的整车热流场模型与空调系统制冷模型,针对重型商用车空调系统在高温怠速与大转矩爬坡工况下的制冷性能进行了仿真分析,并在环境风洞内进行了试验验证,研究了压缩机速比、冷凝器进风温度及流量、鼓风机转速等因素对空调系统性能的影响。结果表明:空调系统仿真结果与试验结果吻合较好,最大误差为4.7%;鼓风机在5000 r/min时可为空调风道提供470 m3/h的风量,怠速工况下冷凝器进风侧平均流速为2.77 m/s,而机舱内的热回流会严重影响空调系统的COP与高低压;针对B车型优化版与Base版,系统的COP较A车型分别下降8.3%和15.8%。

The refrigeration performance of the air-conditioning system in heavy commercial vehicles is severely constrained by specific driving conditions and the engine compartment layout.The thermal-flow field model and AC cooling system model of a heavy-duty truck are built using Star CCM+and AMESim,respectively.The refrigeration performance is analyzed through simulations under high-temperature idling and high-torque climbing conditions.Experimental validation is conducted in an environmental wind tunnel.The effects of compressor speed ratio,condenser inlet air temperature and flow rate,and blower speed on the refrigeration performance are investigated.The simulation results of the air conditioning system are in good agreement with the bench test results,with a maximum error of 4.7%.At 5000 r/min,the blower can provide an air flow rate of 470 m3/h for the air conditioning duct.Under the idle condition,the average flow rate on the inlet side of the condenser is 2.77 m/s.However,thermal reverse flow in the engine compartment severely affects the COP and the high and low pressures of the air conditioning system.For the optimized and base versions of the B-type vehicle,the system COP decreases by 8.3%and 15.8%,respectively,compared to the A-type vehicle.