The friction of the orbiting scroll leads to large power consumption and low energy efficiency of the scroll compressor. The common methods to solve this problem are high cost and a complex process. Considering special structures and operating principles to apply the coating technology on the scroll compressor is a new subject. Given the material of the orbiting scroll being aluminum alloy, the unbalanced magnetron sputtering technology for the orbiting scroll of the scroll compressor was chosen and the Cr transition layer was coated to enhance the bonding strength. Moreover, we innovatively performed an experiment to verify the feasibility of unbalanced magnetron sputtering film coating technology for the diamond-like carbon film coated in the scroll compressor. This article elaborates the parameter test methods of the film properties before and after experiments and the experimental system components. The results showed that the diamond-like carbon film has low coefficient and high bonding strength, which renders it a good wear-reducing effect and an excellent self-lubricating property. Due to the thin film layer and high operating temperature, the thickness should be increased to raise the abrasion resistance. The refrigeration system with the scroll compressor coated with the diamond-like carbon film can satisfy the national standard conditions with low Vickers hardness. Its performance was improved at low speed. Therefore, the unbalanced magnetron sputtering with increased Cr bond layer is a feasible and appropriate technology for coating diamond-like carbon film.

The valve motion strongly couples with the differential pressure between the cylinder and the suction and discharge plenum, which has a significant influence on the performance of the refrigerator compressor. To examine the interaction between the pressure and the reed valve motion, this paper presents an experimental investigation into the inner workings of the refrigerator compressor, particularly the p-V diagram and the motion of the suction valve. The refrigerator compressor was modified to conveniently mount the sensors. Three pressure sensors were installed to measure the p-V diagram and pressure pulsation, while a strain gauge was employed to measure the motion of the suction valve. The interaction between the differential pressure and the valve motion were clearly observed from the experimental results. It was found that there was a considerable power loss up to 14.5% in the suction process under experimental conditions. The sticky force of the oil had a significant effect on both the motion of the suction valve and the suction phase of the compressor. The delayed opening of the reed valve increased the amplitude of the pressure pulsation in the suction plenum. The experimental method which integrates the pressure variety and the valve movement proposed in this paper could contribute to the efficient testing and the optimization of the refrigerator compressor.

The refrigerant mass flow rate of a refrigerator compressor can only be measured by a mass flow meter and heat balance method. This paper focuses on the expansion and compression phase in which the compressor cylinder is closed, and proposes a measurement method of instantaneous mass flow of the refrigerator compressor. The comparison of the experimental pressure variation in the p–V diagram and the theoretical adiabatic process implied that the expansion and compression process of the refrigerator compressor approximated the adiabatic process. Based on the approximations and the experimental p–V diagram, a calculation method for refrigerant mass in the cylinder during the expansion and compression phase is proposed. Subsequently, the mass flow of the refrigerator compressor can be obtained. Furthermore, compared with experimental data and based on the method proposed in this paper, the error of the mass flow rate obtained is less than 3.13%. Based on this calculation method and the experimental p–V diagram, the influence of suction pressure on compressor performance is investigated.

Frosting and fogging of automobile windshields is a common problem that emerges in daily driving. It is important and essential to quickly and completely defrost the windshield for safety purposes. In this study, a three-dimensional mathematical model was applied to investigate the flow distribution and flow characteristics on the windshield of a medium-size Model N800 truck. The simulation results were first compared with experimental data. The results showed that the simulation model could reliably predict the defrosting performance on the windshield. This model was then used to optimize the design of the defrosting duct that comprised the main part of the defroster. It was found that the guide plate and outlet position of the defrosting duct were the two major factors affecting the defrosting performance. Therefore, the guide plate was first optimized and the defrosting performance was analyzed. The results showed that the average pressure loss dropped by 21.56%, while the defrosting efficiency at the front white zone was improved to 89%. The position of the outlet of the airflow was further studied. The results showed that the defrosting efficiency at the front zone could be further improved to 99%.

The material property of orbiting scroll surface, mainly affects the life and performance of scroll compressors. Generally, the anodic oxide film (AOF) is used in the surface treatment of the domestic orbiting scroll, which has numerous drawbacks such as poor adhesion of the film-substrate and easy wear failure. In this paper, a process producing the diamond-like carbon film (DLCF) on the surface of an orbiting scroll by unbalanced magnetron sputtering technology was proposed based on the mechanical characteristics of the scroll compressor and the surface treatment method of the orbiting scroll. The friction coefficient, microhardness, film-substrate adhesion and other performances of the AOF and DLCF were analyzed from the data measured by various test facilities. The refrigeration capacity, power and volumetric efficiency of compressors with different coatings were analyzed and compared by tests under different operating conditions with fixed values of refrigerant charge and oil content. The surface morphology of the coatings was then studied by scanning electron microscope to identify the microstructure after the operation. The results showed that a more even and dense surface was obtained by the DLCF compared with the AOF, which improved the wear resistance of the surface. The surface friction coefficient was only 0.11 as the Cr transition layer markedly enhanced the bonding strength. The DLCF displayed more properties of graphite with the thickness of only 0.73 μ m. The volumetric efficiency of the compressor under the nominal operating condition increased by 5.8%.