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根据汽车空调系统的工作原理、导致空调系统出现结霜现象的几种情况,对市场上某款商务车夏季出现的蒸发器结霜现象进行问题分析、实车测试,最终找到症结所在,解决结霜问题。 相似文献
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正确使用1.汽车空调使用前,应先起动发动机后开启空调,以免因起动机起动负荷过大而造成起动困难。2.普通空调的操作盘上有温度开关和风量开关,使用时必须使低温挡配合高风速挡、高温挡配合低风速挡,以防因蒸发器结霜而降低空调制冷效果。3.汽车在阳光下停放时间过长时,车内温度 相似文献
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六、SD压缩机的产品规格(见下表) 七、变排量压缩机的开发 在定排量压缩机及采用热力膨胀阀的制冷系统中(简称为TXV系统),采用反馈作用控制膨胀阀的开度,以维持蒸发器出口过热度恒定,防止压缩机发生液击。当工况变化时,膨胀阀的开度周期性波动(振荡),使出风温度波动,加上用温控器控制离合器的吸合以防止蒸发器结霜,进一步造成空调工况的波动,并增加噪声,对汽车动力有冲击,影响车辆 相似文献
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本文搭建了采用逆循环化霜的跨临界CO_2电动汽车空调系统实验台。通过对各参数点温度和压力变化的分析,研究了空调系统在结霜过程的性能和参数变化特性。通过记录化霜时间和实时霜层摄像探究了化霜的效果,进行连续结霜—化霜实验,探究了首次化霜对二次结霜情况和化霜时间的影响。实验结果表明,空调系统连续运行结霜150min后,制热量分别下降22.6%和15.6%。第二次结霜速度比第一次更慢,第一次化霜时长为420s,第二次化霜时长为120s,仅为第一次化霜时间的28.5%。逆循环化霜效果十分理想,将成为未来电动汽车空调最合理有效的化霜方式之一。 相似文献
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针对纯电动汽车热泵型空调除湿问题,提出两种除湿模式——双蒸发器(双蒸)热泵除湿模式和单室内蒸发器(单蒸)热泵除湿模式,通过模拟实际工况进行除湿性能试验研究,对比分析了两种除湿模式的除湿速率、出风温度和系统除湿热泵性能系数。结果显示,蒸发压力是除湿效果的重要影响因素,通过调节压缩机转速、电子膨胀阀(EXV)开度控制蒸发压力,可避免结霜和无除湿效果的发生,且在有除湿效果的蒸发压力范围内改变蒸发压力可调节除湿的速率;在满足除湿要求的前提下,双蒸除湿模式可以大幅提高出风温度以提升车室内舒适度。 相似文献
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青藏铁路昆仑山隧道防冻胀结构研究 总被引:2,自引:0,他引:2
结合青藏铁路昆仑山隧道,分析了多年冻土地区隧道冻胀产生的原因,提出了“一次衬砌+防水隔热层+二次衬砌”的新型防冻胀结构型式。通过对昆仑山隧道现场气温、地温和洞内围岩温度、冻胀力、初期支护和二次衬砌应力等一系列的测试表明,该结构安全可靠,昆仑山隧道的建成使多年冻土隧道的修建技术取得了长足的进步. 相似文献
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Jahedul Islam Chowdhury Bao Kha Nguyen David Thornhill 《International Journal of Automotive Technology》2017,18(4):589-601
The supercritical Organic Rankine Cycle (ORC) for the Waste Heat Recovery (WHR) from Internal Combustion (IC) engines has been a growing research area in recent years, driven by the aim to enhance the thermal efficiency of the ORC and engine. Simulation of a supercritical ORC-WHR system before a real-time application is important as high pressure in the system may lead to concerns about safety and availability of components. In the ORC-WHR system, the evaporator is the main contributor to thermal inertia of the system and is considered to be the critical component since the heat transfer of this device influences the efficiency of the system. Since the thermo-physical properties of the fluid at supercritical pressures are dependent on temperature, it is necessary to consider the variations in properties of the working fluid. The wellknown Finite Volume (FV) discretization method is generally used to take those property changes into account. However, a FV model of the evaporator in steady state condition cannot be used to predict the thermal inertia of the cycle when it is subjected to transient heat sources. In this paper, a dynamic FV model of the evaporator has been developed and integrated with other components in the ORC-WHR system. The stability and transient responses along with the performance of the ORC-WHR system for the transient heat source are investigated and are also included in this paper. 相似文献
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多孔混凝土材料组成与路用性能研究 总被引:3,自引:0,他引:3
提出了路面多孔混凝土透水基层材料的配合比设计方法,试验表明该种材料具有较高的强度及透水能力。通过试验及机理分析得出其具有较小的温度及干燥收缩性、良好的抗冻性等路用性能。 相似文献
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In this study, a parallel flow condenser and laminated evaporator for an automotive air-conditioning system were modified
to improve performance. Gas-liquid separation type condensers, in which the condenser and receiver drier are integrated, and
one-tank laminated type evaporators were developed, and their performances were investigated experimentally using HFC-134a.
Heat transfer characteristics in the condenser are examined by means of air temperature, air velocity entering the condenser
and inlet pressure of the refrigerant; heat transfer characteristics in the evaporator are examined by means of air temperature,
relative humidity, flow rate of air, outlet pressure of refrigerant and superheat. Pressure drops for both evaporator and
condenser are also measured, and correlations for pressure drop are derived for the condenser and evaporator, respectively.
Air velocity and mass flow rate of the refrigerant have a significant effect on the overall heat transfer coefficient, and
flow pass is not significantly influenced by the cooling capacity of the condenser. The overall heat transfer coefficient
of the evaporator increases as air flow rate, air temperature and relative humidity increases. 相似文献