Dynamic Behavior of the Discharge Valve in A Moving Coil Oil-free Linear Compressor for Refrigeration Cycle

In thermal control field, the linear compressor attracts a great deal of attention with the benefits of simple compactness structure, high efficiency and variable capacity. The discharge valve has a significant influence on the efficiency and reliability of the compressor and thus the investigation of discharge valve dynamics is greatly necessary. In this paper, an oil-free linear compressor is developed and a test system incorporated into the compressor performance test rig is set up to investigate the dynamics of the discharge valve. While varying linear compressor marked features, the movement of discharge valve is measured to figure out the marked features that influence the valve dynamics. The experimental results indicate that the high-frequency could increase the area of under the displacement curve, valve lift and compressor efficiency; High piston stroke have the similar phenomenon; from the p-V indicated diagram, the discharge power loss is higher than the suction power loss. The valve lift additional displacement fluctuations after piston reaches to the top dead center. This phenomenon can be improved by valve seat materials or surface roughness. According to the results, the design and optimization of the valve can be done with a clear aim and it also offers a new visual angle for capacity modulation of a compressor.