The automatic expansion valve is designed to maintain what?

The automatic expansion valve is specifically engineered to maintain constant evaporator pressure. This is achieved through a feedback mechanism that adjusts the valve opening based on the pressure within the evaporator system. By maintaining a consistent pressure, the valve ensures optimal performance of the refrigeration cycle, allowing for efficient heat absorption and effective temperature control.

In contrast, the other options—constant evaporator temperature, constant refrigerant flow, and constant evaporator superheat—are not the primary functions of the automatic expansion valve. While these factors can be influenced by the valve's operation, the main design purpose is centered on controlling the evaporator pressure to create a stable environment for proper refrigerant phase transition. This stability is crucial for maximizing system efficiency and preventing issues such as refrigerant starvation or flooding.