Research Progress on Vapor Injection Heat Pump System for Electric Vehicles

Vapor injection is an effective method to improve the performance of heat pump system for electric vehicles at low temperature. This paper gives a detailed overview of the main research on vapor injection technology. Flash tank cycle (FTC) and internal heat exchanger cycle (IHXC) are two typical vapor injection cycles. The two cycles are discussed and compared in detail. At the same time, the influence of injection port and injection pressure on the system is also analyzed, which provides direction for system optimization. Based on the literature research, the possible future research directions are proposed and discussed.