Fusion FWD V6-3.5L (2010)
Expansion Block/Orifice Tube: Description and Operation
Thermostatic Expansion Valve (TXV)
Air Conditioning
The refrigerant system components include the following:
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Pulley-driven A/C compressor (non-hybrid)
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Electric A/C compressor (hybrid)
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A/C clutch assembly (non-hybrid)
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A/C condenser core
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A/C evaporator core
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Receiver/drier cartridge
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Connecting refrigerant lines
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Thermostatic Expansion Valve (TXV)
The refrigerant system incorporates an A/C compressor controlled by the PCM through an A/C clutch relay. The HVAC module sends an A/C request
signal to the Instrument Cluster (IC), which relays the request to the PCM. An evaporator discharge air temperature sensor is used to disengage the A/C
compressor clutch when the evaporator core temperature falls below an acceptable temperature.
The A/C compressor clutch will only be engaged by the PCM if all of the following conditions are met:
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The HVAC module is set to a mode which provides an A/C request to the PCM via the IC.
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The evaporator discharge air temperature sensor is reading an acceptable temperature.
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The A/C pressure transducer is reading an acceptable pressure in the high side of the refrigerant system.
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The A/C compressor relay is switched to the closed position by the PCM.
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The engine coolant temperature is not excessively high.
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The PCM has not detected a Wide Open Throttle (WOT) condition.
NOTE: To prevent erroneous readings that can result from underhood heat sources, the PCM uses data from several sources to calculate ambient
temperature. The vehicle must be driven for a sufficient time, speed and distance after startup before the calculated ambient temperature is updated in the
PCM. If a vehicle is moved from a below-freezing environment to a warm environment (such as being moved from outside into a garage or when
delivered from a cold climate to a warm climate), the minimal amount of driving may not be sufficient for the calculated ambient temperature to be
updated. In this event, the PCM will believe the ambient temperature is too low for A/C operation and, to prevent an increased risk of compressor
slugging or damage, will not engage the A/C compressor in any mode. To manually reset the PCM calculated ambient temperature to the current
temperature, run the vehicle until the thermostat opens and then clear the PCM Keep Alive Memory (KAM). For the KAM resetting procedure, refer to
Computers and Control Systems Information. When the PCM KAM is reset, the ambient temperature will reset to the current higher value (a value closer
to actual surrounding conditions) and the A/C compressor will operate normally.
An A/C pressure relief valve is installed in the A/C compressor to protect the refrigerant system against excessively high refrigerant pressures.
Refrigerant flow into the evaporator core is metered by a TXV.
Thermostatic Expansion Valve (TXV)
The TXV is located between the evaporator core inlet and outlet tubes and the TXV manifold and tube assembly at the rear of the engine compartment.
The TXV provides a restriction to the flow of refrigerant from the high-pressure side of the refrigerant system and separates the low-pressure and
high-pressure sides of the refrigerant system. Refrigerant entering and exiting the evaporator core passes through the TXV through 2 separate flow paths.
An internal temperature sensing bulb senses the temperature of the refrigerant flowing out of the evaporator core and adjusts an internal pin-type valve to
meter the refrigerant flow into the evaporator core. The internal pin-type valve decreases the amount of refrigerant entering the evaporator core at lower
temperatures and increases the amount of refrigerant entering the evaporator core at higher temperatures.
