Infiniti QX56 (Z62). Manual - part 783

 

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Infiniti QX56 (Z62). Manual - part 783

 

 

SYSTEM

HAC-23

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

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REAR AUTOMATIC AIR CONDITIONING SYSTEM : System Diagram

INFOID:0000000006275869

REAR AUTOMATIC AIR CONDITIONING SYSTEM : System Description

INFOID:0000000006275870

• Rear automatic air conditioning system is controlled by each function of A/C auto amp..

Control by A/C auto amp.

-

HAC-24, "REAR AUTOMATIC AIR CONDITIONING SYSTEM : Air Flow Control"

-

HAC-25, "REAR AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control"

-

HAC-26, "REAR AUTOMATIC AIR CONDITIONING SYSTEM : Door Control"

-

HAC-27, "REAR AUTOMATIC AIR CONDITIONING SYSTEM : Temperature Control"

- Correction for input value of each sensor

Ambient sensor (setting temperature correction)

JMIIA0818GB

HAC-24

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

SYSTEM

• A/C auto amp. controls passenger room temperature so that the optimum level always matches the temper-

ature level that passenger may feel. Correction is applied to the target temperature that is set using temper-
ature control dial, according to ambient temperature detected by ambient sensor.

Rear in-vehicle sensor [in-vehicle temperature (rear side) correction]

• Passenger room temperature (rear side) detected by rear in-vehicle sensor is corrected for each rear auto-

matic air conditioning control.

Intake sensor (intake temperature correction)

• A/C auto amp. performs correction to change recognition intake temperature of A/C auto amp. quickly when

difference is large between recognition intake temperature and intake temperature detected by intake tem-
perature sensor. The correction is performed to change recognition intake temperature slowly when differ-
ence is small.

Sunload sensor (sunload amount correction)

• Sunload amount detected by sunload sensor is corrected for each rear automatic air conditioning control.
• A/C auto amp. performs correction to change recognition sunload amount of A/C auto amp. slowly when

sunload amount changes quickly, for example when entering or exiting a tunnel.

• Front control

Operation by front controller

- Front A/C control (preset switch) transmits the commands for rear automatic air conditioning system opera-

tion to AV control unit via communication line, then AV control unit transmits the commands to A/C auto amp.
via CAN communication. A/C auto amp. transmits each indication information to AV control unit via CAN
communication. AV control unit displays each indication information that is received.

Operation by rear controller

- Rear A/C control transmits the commands for rear automatic air conditioning system operation to A/C auto

amp. via communication line.

REAR AUTOMATIC AIR CONDITIONING SYSTEM : Air Flow Control

INFOID:0000000006275871

DESCRIPTION

• A/C auto amp. changes duty ratio of blower motor drive signal and controls air flow continuously. When air

flow is increased, duty ratio of rear blower motor control signal gradually increases to prevent a sudden
increase in air flow. 

• In addition to manual control and automatic control, air flow control is compose of starting fan speed control,

low coolant temperature starting control, high in-vehicle temperature starting control and fan speed control at
door motor operation

AUTOMATIC AIR FLOW CONTROL

• A/C auto amp. decides target air flow depending on target rear air mix door opening angle. 
• A/C auto amp. changes duty ratio of rear blower motor control signal and controls the air flow continuously

so that air flow matches to target air flow. 

• When air outlet is VENT or B/L, the minimum air flow is changed

depending on sunload.

STARTING AIR FLOW CONTROL

JMIIA0738GB

SYSTEM

HAC-25

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

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• When rear blower motor is activated, A/C auto amp. gradually

increases duty ratio of rear blower motor control signal to prevent a
sudden increase in discharge air flow.

• It takes approximately 8 seconds for air flow to reach HI from LOW. 

LOW COOLANT TEMPERATURE STARTING CONTROL

If the engine coolant temperature is 56

°

C (133

°

F) or less, to prevent

a cold discharged air flow, A/C auto amp. suspends rear blower
motor activation for the maximum 150 seconds depending on target
rear air mix door opening angle. After this, rear blower motor control
signal is increased gradually, and rear blower motor is activated.

HIGH IN-VEHICLE TEMPERATURE STARTING CONTROL

When front evaporator fin temperature is high [intake sensor value is 35

°

C (95

°

F) or more], to prevent a hot

discharged air flow, A/C auto amp. suspends rear blower motor activation for approximately 3 seconds so that
rear evaporator is cooled by refrigerant. 

FAN SPEED CONTROL AT DOOR MOTOR OPERATION

When rear mode door motor is activated while air flow is more than the specified value, A/C auto amp.
reduces temporarily fan speed wo that rear mode door moves smoothly. 

REAR AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control

INFOID:0000000006275872

• While air outlet is in automatic control, A/C auto amp. selects the

rear mode door position depending on a target rear air mix door
angle and outlet air temperature calculated from sunload.

JMIIA0739GB

JMIIA0740GB

JMIIA0733GB

HAC-26

< SYSTEM DESCRIPTION >

[AUTOMATIC AIR CONDITIONING]

SYSTEM

REAR AUTOMATIC AIR CONDITIONING SYSTEM : Door Control

INFOID:0000000006275873

DOOR MOTOR CONTROL

• LCU (Local Control Unit) is built in to each door motor. And detects door position by PBR (Potentio Balance

Resistor).

• A/C auto amp. communicates with each LCU via communication line. And receives each door position feed

back signal from each LCU.

• Each LCU controls each door to the appropriate position depending on the control signal from A/C auto amp.

when the door movement is complete, transmits the signal of door movement completion to A/C auto amp.

SWITCHES AND THEIR CONTROL FUNCTION

JMIIA0729GB

1.

Rear blower motor

2.

Rear evaporator

3.

Rear air mix door

4.

Rear heater core

5.

Rear mode door

Recirculation air

Rear ventilator

Rear A/C foot

Switch/Dial position

Door position

Rear mode door

Rear air mix door

AUTO switch

Front A/C control

AUTO

Rear A/C control

JMIIA0744ZZ

 

 

 

 

 

 

 

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