A/C COMPRESSOR CONTROL [FULL-AUTO AIR CONDITIONER]

id0740a1108000

Purpose

• The A/C compressor control switches the A/C compressor on/off according to the vehicle environment.

Function

• The A/C compressor control performs A/C compressor on/off determination based on the switch/dial operation built into the climate control unit, and signals from each sensor.

• The A/C compressor control has manual and auto controls.

• The A/C compressor control performs the following correction:

― Defroster correction

A/C compressor automatic control

• The climate control unit determines the A/C signal on/off in accordance with the air conditioner operation status such as A/C ON mode (A/C switch ON) or AUTO mode (AUTO switch ON).

• In A/C ON mode, the A/C signal (magnetic clutch) is turned on/off based on the ambient temperature and the temperature of the air passing through the evaporator.

• In AUTO mode, the A/C signal (magnetic clutch) is turned on/off based on the ambient temperature and the temperature of the air passing through the evaporator. The ambient temperature calculation value is calculated based on the ambient temperature, set temperature, cabin temperature, and sunlight intensity.

• When the ambient temperature is low, the A/C signal off temperature is set low to prevent window fogging.

A/C mode

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AUTO mode (except MZ-CD 1.6)

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A/C compressor manual control

• A/C ON or OFF mode is selected by operating the A/C switch.

A/C mode

Operation condition

A/C ON mode

A/C MODE (A/C display)

Fixed in A/C mode.

A/C OFF mode (No display)

Fixed in A/C OFF mode.

A/C mode	Operation condition
A/C ON mode	A/C MODE (A/C display)	Fixed in A/C mode.
A/C OFF mode (No display)	Fixed in A/C OFF mode.

Correction

Defroster correction (except MZ-CD 1.6)

• When the DEFROSTER switch is turned on, the system is switched to A/C ON mode and the A/C signal on/off temperature is set to 5.0/4.0 °C {41/39 °F} to improve defrosting. However, defroster correction is not performed with the ambient temperature correction.

Construction

• The A/C compressor control consists of the parts indicated in the following table:

Input device

Control part

Output device

•  A/C switch (climate control unit)

•  Mode switch (climate control unit)

•  Temperature control dial (climate control unit)

•  Refrigerant pressure sensor / switch

•  Solar radiation sensor

•  Passenger compartment temperature sensor

•  Evaporator temperature sensor

•  Ambient temperature sensor

•  Climate control unit

•  PCM

•  BCM

•  Instrument cluster

•  A/C relay

•  Magnetic clutch (A/C compressor)

Input device	Control part	Output device
• A/C switch (climate control unit) • Mode switch (climate control unit) • Temperature control dial (climate control unit) • Refrigerant pressure sensor / switch • Solar radiation sensor • Passenger compartment temperature sensor • Evaporator temperature sensor • Ambient temperature sensor	• Climate control unit • PCM • BCM • Instrument cluster	• A/C relay • Magnetic clutch (A/C compressor)

Operation

1. The climate control unit performs the A/C ON/OFF determination based on each switch/dial operation and signals from each sensor which changes according to the vehicle environment.

2. The climate control unit sends the A/C signal determined by the results and corrections of the A/C ON/OFF determination, and the refrigerant pressure signal input from the A/C pressure sensor to the PCM.

3. The PCM turns on the A/C relay based on the A/C signal and refrigerant pressure signal input, and the A/C compressor magnetic clutch turns on.

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