Influence of asymmetrical features of scroll plates on thermodynamic processes and orbiting scroll dynamic characteristics of electric vehicle scroll compressors

Abstract

The electric scroll compressor is the main energy-consuming component of the thermal management system of electric vehicles and has been widely used for this application. To meet the needs of the entire vehicle, the scroll compressor is developing towards miniaturization. However, this trend often causes the compressor to have shorter scroll wraps and may require high rotational speeds for operation. As a result, changes in the structures of scroll plates have already appeared, including different lengths between fixed and orbiting scroll wraps, an off-center discharge port, asymmetrically positioned bypass ports, a crescent groove at the start of the orbiting scroll, and scroll wrap offsetting. Although these features, referred to as asymmetrical features in this paper, fundamentally change the thermodynamic process within the scroll chambers and dynamic characteristics of the orbiting scroll plate, no study has comprehensively discussed them or their impacts. Clarifying the mechanism and extent of these features is a worthwhile endeavor that will help guide the future design and optimization of scroll plates. Therefore, a mathematical model of the thermodynamic process and dynamic analysis was established in this study. An experiment was then conducted to confirm the model validation. Four working conditions under different pressure ratios and rotational speeds were selected to perform the simulation. The impacts of the working conditions and asymmetrical features on pressure and temperature changes within the scroll chambers and changes in the forces and moments acting on the orbiting scroll plate were compared and analyzed.