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2026. 6. 30. 작업

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Does AC usage change based on blower speed?

처리 내용

AC load absolutely varies with blower speed. On most modern vehicles (like your CRV, without an orifice tube) the amount of liquid refrigerant metered into the evaporator is controled by a Thermal Expansion Valve, or "TXV". The TXV takes it's cue from the temperature of the evaporator core. Here's a great desciption of (stationary) TXV operation Critical here is the pressure balance operation of the TXV: TXV Pressure Balance EquationTXV P1+P4 = P2+P3 P1 = Bulb Pressure (Opening Force) P2 = Evaporator Pressure (Closing Force) P3 = Superheat Spring Pressure (Closing Force) P4 = Liquid Pressure (Opening Force) Note that the "bulb" (P1) is a sealed system, with a refrigerant inside, but unrelated to the refrigerant in the rest of the system. The bulb is physically buried in the evaporator core, and reads the temperature of the core by thermal conductivity. The pressure inside the bulb rises as the core temperature increases. This pressure cooperates with the head pressure to open the TXV a