电动车跨临界CO₂ 热系统多解耦合诱发 控制失效机制

To investigate the discharge pressure issue in transcritical CO₂ thermal systems for electric vehicles under conventional high-precision empirical formula prediction methods and clarify the mechanism of mult-i solution coupling induced control failure, the control failure in such transcritical CO₂ thermal systems under variable operating conditions is compared and analyzed.By deeply examining the variable correlations in conventional optimal pressure control methods and the multi-solution convergence characteristics of dynamic system control, the mechanism underlying control failure in CO₂ thermal systems during dynamic operation of electric vehicles is fundamentally revealed. Based on this, a control method to suppress dynamic failure under variable conditions in electric vehicle CO₂ thermal systems is proposed.The results indicate that the initial boundary conditions affect the convergence of CO₂ dynamic control. Under failure modes, the system's energy efficiency ratio decreases by nearly 30%.The coupling characteristics between the gas cooler outlet and the expansion valve inlet temperatures, determined by the thermophysical properties of supercritical CO₂, may be the direct cause of thermodynamic multi-solutions and dynamic failure. The proposed control method enables effective convergence to the desired operating condition among multiple solutions during dynamic operation. It provides theoretical insights into pressure control issues in automotive transcritical CO₂ air conditioning systems.