air conditioning INFINITI QX56 2011 Factory Manual PDF

HAC-12
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
COMPONENT PARTS
Aspirator
INFOID:0000000006275856
The aspirator generates the vacuum by the air blown from the heater
& cooling unit and draws the air of the passenger room to the front
in-vehicle sensor area via the aspirator duct.
Front Blower MotorINFOID:0000000006275857
The front blower motor utilizes a brush-less motor with a rotating
magnet. Quietness is improved comparing to a conventional motor
(brush motor) that rotates coil while brush functions as contact
points.
Front display Front display indicates operation status of ACCS (advanced climate control
system).
Heater & cooling unit as-
sembly Ionizer Ionizer generates an approximately equal proportional amount of positive
and negative ions in the air.
Preset switch Preset switch is integrated with front A/C control and AV operation switch.
Front A/C control operation signal is transmitted from preset switch to AV
control unit via communication line.
Component Description
RJIA1804E
RJIA2467J
ZHA152H
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COMPONENT PARTSHAC-13
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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Rear Blower MotorINFOID:0000000006275858
The rear blower motor utilizes a brush-less motor with a rotating
magnet. Quietness is improved comp aring to a conventional motor
(brush motor) that rotates coil while brush functions as contact
points.
Refrigerant Pressure SensorINFOID:0000000006275859
Description
Refrigerant pressure sensor is installed to upper porti on of liquid tank. The refrigerant pressure sensor con-
verts high-pressure side refrigerant pressure into vo ltage and outputs it to ECM. ECM operates cooling system
protection and idle speed control according to voltage value that is input.
Structure and operation
The refrigerant pressure sensor is a capacitance type sensor. It consists of a pressure detection area and a
signal processing area. The pressure detection area, wh ich is a variable capacity condenser, changes internal
static capacitance according to pressure force. The signal processing area detects the static capacitance of
the pressure detection area, converts the static capacitance into a voltage value, and transmits the voltage
value to ECM.
RJIA2467J
ZHA152H
PBIB2657E
Revision: 2010 May2011 QX56

HAC-14
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
SYSTEM
FRONT AUTOMATIC AIR CONDITIONING SYSTEM
FRONT AUTOMATIC AIR CONDITION
ING SYSTEM : System DiagramINFOID:0000000006275860
FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : System DescriptionINFOID:0000000006275861
 Front automatic air conditioning system is controlled by each function of A/C auto amp., ECM and IPDM E/
R.
Control by A/C auto amp.- HAC-15, "FRONT AUTOMATIC AIR CONDITIONING SYSTEM : Air Flow Control"
-HAC-16, "FRONT AUTOMATIC AIR CONDITIONING SYSTEM : Air Inlet Control"
JMIIA0816GB
Revision: 2010 May2011 QX56

SYSTEMHAC-15
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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- HAC-17, "FRONT AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control"
-HAC-17, "FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Compressor Control"
-HAC-18, "FRONT AUTOMATIC AIR CONDITION ING SYSTEM : Door Control"
-HAC-21, "FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Temperature Control"
- Correction for input value of each sensor
Ambient sensor (setting temperature correction) 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.
Front in-vehicle sensor [in-vehicle temperature (front side) correction]
 Passenger room temperature (front side) detected by front in-vehicle sensor is corrected for each front air
conditioning control (driver side and passenger side)
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 temperat ure 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 correc ted for each air conditioning control (driver side and
passenger side).
 A/C auto amp. performs correction to change recogni tion sunload amount of A/C auto amp. slowly when
sunload amount changes quickly, for exampl e when entering or exiting a tunnel.
Control by ECM
- Cooling fan control
Refer to EC-41, "
COOLING FAN CONTROL : System Description".
- Air conditioning cut control.
Refer to EC-47, "
AIR CONDITIONING CUT CONTRO L : System Description".
Control by IPDM E/R- Relay control
Refer to PCS-5, "
RELAY CONTROL SYSTEM : System Description".
- Cooling fan control
Refer to PCS-8, "
POWER CONTROL SYSTEM : System Description".
 Front A/C control (preset switch) transmits the co mmands for front 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.
FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Air Flow ControlINFOID:0000000006275862
DESCRIPTION
 A/C auto amp. changes duty ratio of blower motor dr ive signal and controls air flow continuously. When air
flow is increased, duty ratio of front blower moto r control signal gradually increases to prevent a sudden
increase in air flow.
 In addition to manual control and automatic control, air flow control is consist of starting fan speed control,
low coolant temperature starting control, high in-vehi cle 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 front air mix door opening angle.
 A/C auto amp. changes duty ratio of front blower moto r control signal and controls the air flow continuously
so that air flow matches to target air flow.
Revision: 2010 May2011 QX56

HAC-16
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
 When air outlet is VENT or B/L, the minimum air flow is changed
depending on sunload.
STARTING AIR FLOW CONTROL
 When front blower motor is activated, A/C auto amp. graduallyincreases duty ratio of front 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 front blower
motor activation for the maximum 150 seconds depending on target
front air mix door opening angle. After this, front blower motor control
signal is increased gradually, and front 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 front blower motor activation for approximately 3 seconds so that
front evaporator is cooled by refrigerant.
FAN SPEED CONTROL AT DOOR MOTOR OPERATION
When front mode door motor is activated while air flow is more than the specified value, A/C auto amp.
reduces temporarily fan speed wo that front mode door moves smoothly.
FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Air Inlet ControlINFOID:0000000006275863
The intake door is automatically controlled by the temperature set-
ting, ambient temperature, in-vehicle temperature (front side), intake
temperature, amount of sunload and ON/OFF operation of the com-
pressor.
Intake door automatic control selects FRE, 20% FRE, or REC
depending on a target front air mix door opening angle, based on in-
vehicle temperature (front side) , ambient temperature, and sunload.
JMIIA0735GB
JMIIA0736GB
JMIIA0737GB
JMIIA0732GB
Revision: 2010 May2011 QX56

SYSTEMHAC-17
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Air Outlet ControlINFOID:0000000006275864
 While air outlet is in automatic control, A/C auto amp. selects the
front mode door position depending on a target front air mix door
angle and outlet air temperature calculated from sunload.
 If ambient temperature is excessively low, D/F is selected to pre- vent windshield fogging when air outlet is set to FOOT.
FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Compressor Control
INFOID:0000000006275865
DESCRIPTION
 When the compressor activation condition is satisfied while blower motor is activated, A/C auto amp. trans-
mits A/C ON signal and blower fan ON signal to ECM via CAN communication.
 ECM judges that the compressor can be activated depending on each sensors state (refrigerant pressure sensor signal, and others). And transmits A/C compress or request signal to IPDM E/R via CAN communica-
tion.
 IPDM E/R turns A/C relay ON and activates the compressor depending on request from ECM.
COMPRESSOR PROTECTION CONTROL AT PRESSURE MALFUNCTION
When high-pressure side value that is detected by refri gerant pressure sensor is as per the following state,
ECM requests IPDM E/R to turn A/C relay OFF and stops the compressor.
 3.12 MPa (31.82 kg/cm
2, 452.4 psi) or more (When the engine speed is less than 1,500 rpm)
 2.74 MPa (27.95 kg/cm
2, 397.3 psi) or more (When the engine speed is 1,500 rpm or more)
 0.14 MPa (1.43 kg/cm
2, 20.3 psi) or less
COMPRESSOR OIL CIRCULATION CONTROL
When the engine starts while the engine coolant temperature is 56 °C (133 °F) or less, ECM activates the com-
pressor for approximately 6 seconds and circulates the compressor lubricant once.
LOW TEMPERATURE PROTECTION CONTROL
 When intake sensor detects that front evaporator fin temperature is
2.5 °C (37 °F) or less, A/C auto amp. requests ECM to turn com-
pressor OFF, and stops the compressor.
 When the front evaporator fin temperature returns to 5.0 °C (41 °F)
or more, the compressor is activated.
OPERATING RATE CONTROL
When set temperature is other than fully cold or air out let is “VENT”, “B/L” or “FOOT” A/C auto amp. controls
the compressor activation depending on ambient temperature.
AIR CONDITIONING CUT CONTROL
When set engine is running is excessively high load conditi on, ECM requests IPDM E/R to turn A/C relay OFF,
and stops the compressor. Refer to EC-47, "
AIR CONDITIONING CUT CONTRO L : System Description" for
details.
JMIIA0730GB
JMIIA0742GB
Revision: 2010 May2011 QX56

HAC-18
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
FRONT AUTOMATIC AIR CONDITION ING SYSTEM : Door Control
INFOID:0000000006275866
DOOR MOTOR CONTROL
 LCU (Local Control Unit) is built in to each door moto r. And detects door position by PBR (Potentio Balance
Resistor).
 A/C auto amp. communicates with each LCU via comm unication line. And receives each door position feed
back signal from each LCU.
 Each LCU controls each door to the appropriate pos ition 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
With ACCS (Advanced Climate Control System)
JMIIA0817GB
JMIIA0727ZZ
Revision: 2010 May2011 QX56

SYSTEMHAC-19
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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*: Inlet status is displayed by indi cator when activating automatic control
Without ACCS (Advanced Climate Control System)
1. Intake door 2. In-cabin microfilter 3. Blower motor
4. Evaporator 5. Air mix door (Driver side/Passenger
side)6. Heater core
7. Foot door 8. Ventilator door 9. Upper ventilator door
10. Defroster door Fresh air intake Recirculation air
Center ventilator Side ventilator Upper ventilator
Foot Rear foot Defroster
Switch/Dial position Door position
Ventilator door Foot
doorDefroster
door Intake
door Upper
ventilator
door Air mix
door
(Driver side) Air mix
door
(Passen-
ger
side)
AUTO switch AUTO — AUTO
MODE switch VENT H E N —
B/L I F N —
FOOT J G O — D/F J G O B —
DEF switch J E P B K —
Intake switch
*FRE — B —
REC — A —
Upper ventila- tor switch ON — L – M —
OFF — K —
Temperature control dial
(Driver side) DUAL
switch:
OFF18.0
°C (60 °F) — C
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO
32.0 °C (90 °F) — D
Temperature control dial
(Driver side) DUAL
switch:
ON18.0
°C (60 °F) — C —
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO—
32.0 °C (90 °F) — D —
Temperature control dial
(Passenger side) 18.0
°C (60 °F) — C
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO
32.0 °C (90 °F) — D
OFF switch AUTO —
Revision: 2010 May2011 QX56

HAC-20
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
1. Intake door 2. In-cabin microfilter 3. Blower motor
4. Evaporator 5. Air mix door (Driver side/Passenger
side)6. Heater core
7. Foot door 8. Ventilator door 9. Upper ventilator door
10. Defroster door Fresh air intake Recirculation air
Center ventilator Side ventilator Upper ventilator
Foot Rear foot Defroster
JMIIA0727ZZ
Switch/Dial position Door position
Ventilator door Foot
doorDefroster
door Intake
door Upper
ventilator door Air mix
door
(Driver side) Air mix
door
(Passen- ger
side)
AUTO switch AUTO — AUTO
MODE switch VENT H E N —
B/L I F N —
FOOT J G O — D/F J G O B —
DEF switch J EPBK —
FRE switch
*—B—
REC switch
*—A—
Upper ventila- tor switch ON — L – M —
OFF — K —
Revision: 2010 May2011 QX56

SYSTEMHAC-21
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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*: Inlet status is displayed by indi cator when activating automatic control
AIR DISTRIBUTION
FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Temperature Control
INFOID:0000000006275867
 When ignition switch is in the ON position, A/C auto amp. always
automatically controls temperatur e regardless of front air condi-
tioning operational state.
 A/C auto amp. calculates the target front air mix door opening angle depending on set temperature, in-vehicle temperature (front
side), ambient temperature, and sunload.
 Front air mix door is controlled depending on the comparison of current front air mix door opening angle and target front air mix
door opening angle.
 Regardless of in-vehicle temperature (front side), ambient temper- ature, and sunload, front air mix door is fixed at the fully cold posi-
tion when set temperature is 18.0 °C (60 °F), and at the fully hot
position when set temperature is 32.0 °C (90 °F).
FRONT AUTOMATIC AIR CONDITI ONING SYSTEM : Fail-safeINFOID:0000000006275868
FAIL-SAFE FUNCTION
Temperature
control dial
(Driver side) DUAL
switch:
OFF18.0
°C (60 °F) — C
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO
32.0 °C (90 °F) — D
Temperature control dial
(Driver side) DUAL
switch:
ON18.0
°C (60 °F) — C —
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO—
32.0 °C (90 °F) — D —
Temperature control dial
(Passenger
side) 18.0
°C (60 °F) — C
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO
32.0 °C (90 °F) — D
OFF switch AUTO —
Switch/Dial position
Door position
Ventilator door Foot
doorDefroster
door Intake
door Upper
ventilator door Air mix
door
(Driver side) Air mix
door
(Passen- ger
side)
Discharge air flow
Mode position Condition Air outlet/distribution
VENT FOOT DEF
Center Side Front Rear
DUAL and Up-
per ventilator
switch: OFF 50% 50% — — —
30% 30% 26% 14% —
— 14% 36% 23% 27%
— 12% 32% 20% 36%
—11%——89%
JMIIA0731GB
Revision: 2010 May2011 QX56