INFINITI M35 2007 Factory Service Manual

ATC-20
REFRIGERATION SYSTEM
Revision: 2007 April2007 M35/M45
REFRIGERATION SYSTEMPFP:KA990
Refrigerant CycleNJS000FZ
REFRIGERANT FLOW
The refrigerant flows from the compressor, through the condenser with liquid tank, through the evaporator, and
back to the compressor. The refrigerant evaporation in the evaporator is controlled by an externally equalized
expansion valve, located inside the evaporator case.
FREEZE PROTECTION
To prevent evaporator frozen up, the evaporator air temperature is monitored, and the voltage signal to the
unified meter and A/C amp. will make the A/C relay go OFF and stop the compressor.
Refrigerant System ProtectionNJS000G0
REFRIGERANT PRESSURE SENSOR
The refrigerant system is protected against excessively high- or low-pressures by the refrigerant pressure sen-
sor, located on the liquid tank. If the system pressure rises above, or falls below the specifications, the refriger-
ant pressure sensor detects the pressure inside the refrigerant line and sends the voltage signal to the ECM.
ECM makes the A/C relay go OFF and stops the compressor when pressure on the high-pressure side
detected by refrigerant pressure sensor is over about 3,119 kPa (31.8 kg/cm
2 , 452 psi), or below about 118
kPa (1.2 kg/cm
2 , 17 psi).
PRESSURE RELIEF VALVE
The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor.
When the pressure of refrigerant in the system increases to an unusual level [more than 3,628 kPa (37 kg/cm
2
, 526 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into the
atmosphere.
RJIA1552E

REFRIGERATION SYSTEM
ATC-21
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2007 April2007 M35/M45
Variable Displacement CompressorNJS000G1
GENERAL INFORMATION
1. The variable compressor provides refrigerant control under varying conditions. During cold winters, it may
not produce high refrigerant pressure discharge (compared to previous units) when used with air condi-
tioning systems.
2. For air conditioning systems with the compressor, the clutch remains engaged unless: the system main
switch, fan switch or ignition switch is turned OFF. When ambient (outside) temperatures are low or when
the amount of refrigerant is insufficient, the clutch is disengaged to protect the compressor.

ATC-22
REFRIGERATION SYSTEM
Revision: 2007 April2007 M35/M45
DESCRIPTION
General
The variable compressor is a swash plate type that changes piston stroke in response to the required cooling
capacity.
The tilt of the swash plate allows the piston’s stroke to change so that refrigerant discharge continuously
change from approx. 0 to 171 cm
3 (0 to 10.4 cu in).
RJIA4209E

REFRIGERATION SYSTEM
ATC-23
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2007 April2007 M35/M45
Operation
1. Control Valve
–By changing high-pressure valve lift amount, built-in electronic control valve executes the following:
 Controls high-pressure valve discharge amount.
 Changes crankcase pressure in compressor.
 Changes angle of swash plate.
–Amount of high-pressure valve lift is determined by factors below.
 Low-pressure applied to diaphragm
 Spring load of set spring
 Balance of magnetic force generated in magnet coil
–Electronic control valve (ECV) magnet coil receives electric signal (duty control) from unified meter and A/
C amp. Then, magnetic force generated by electric current is changed to control high-pressure valve lift
amount.
2. Maximum Cooling
High-pressure valve is closed by magnetic force generated by electric signal sent from unified meter and
A/C amp. At this time, cylinder moves full stroke due to pressure balance between inside crankcase (Pc)
and suction line (Ps).
Under this condition, the swash plate is set to the maximum stroke position.
3. Capacity Control
When no electric signal is sent from unified meter and A/C amp. (current: OFF), high-pressure valve is
opened by spring force.
Since suction pressure is low, it makes the suction port close and the discharge port open. Thus, crank-
case pressure becomes high as high-pressure enters the crankcase.
–The force acts around the link near the swash plate, and is generated by the pressure difference before
and behind the piston.
–The thrust flange and link are located where the piston generates the highest pressure. Piston pressure is
between suction pressure Ps and discharge pressure Pd, which is close to suction pressure Ps. If crank-
case pressure Pc rises due to capacity control, the force around the link makes the swash plate angle
decrease and also the piston stroke decrease. In other words, crankcase pressure increase triggers pres-
SJIA0547E

ATC-24
REFRIGERATION SYSTEM
Revision: 2007 April2007 M35/M45
sure difference between the piston and the crankcase. The pressure difference changes the angle of the
swash plate.
SJIA0548E

REFRIGERATION SYSTEM
ATC-25
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2007 April2007 M35/M45
Component LayoutNJS000G2
SJIA1785E

ATC-26
LUBRICANT
Revision: 2007 April2007 M35/M45
LUBRICANTPFP:KLG00
Maintenance of Lubricant Quantity in CompressorNJS000G3
The lubricant in the compressor circulates through the system with the refrigerant. Add lubricant to compres-
sor when replacing any component or after a large refrigerant leakage occurred. It is important to maintain the
specified amount.
If lubricant quantity is not maintained properly, the following malfunctions may result:

Lack of lubricant: May lead to a seized compressor.

Excessive lubricant: Inadequate cooling (thermal exchange interference)
LUBRICANT
LUBRICANT RETURN OPERATION
Adjust the lubricant quantity according to the test group shown below.
1. CHECK LUBRICANT RETURN OPERATION
Can lubricant return operation be performed?

A/C system works properly.

There is no evidence of a large amount of lubricant leakage.
CAUTION:
If excessive lubricant leakage is noted, never perform the lubricant return operation.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2. PERFORM LUBRICANT RETURN OPERATION, PROCEEDING AS FOLLOWS
1. Start the engine, and set to the following conditions:
–Engine speed: Idling to 1,200 rpm
–A/C switch: ON
–Blower speed: Max. position
–Temp. control: Optional [Set so that intake air temperature is 25 to 30°C (77 to 86°F).]
–Intake position: Recirculation (REC)
2. Perform lubricant return operation for about 10 minutes.
3. Stop the engine.
>> GO TO 3.
3. CHECK REPLACEMENT PART
Should the compressor be replaced?
YES >> GO TO AT C - 2 7 , "LUBRICANT ADJUSTING PROCEDURE FOR COMPRESSOR REPLACE-
MENT" .
NO >> GO TO AT C - 2 7 , "
LUBRICANT ADJUSTING PROCEDURE FOR COMPONENTS REPLACE-
MENT EXCEPT COMPRESSOR" . Name : Nissan A/C System Oil Type S

LUBRICANT
ATC-27
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2007 April2007 M35/M45
LUBRICANT ADJUSTING PROCEDURE FOR COMPONENTS REPLACEMENT EXCEPT COM-
PRESSOR
After replacing any of the following major components, add the correct amount of lubricant to the system.
Amount of lubricant to be added:
*1: If the refrigerant leak is small, no addition of lubricant is needed.
LUBRICANT ADJUSTING PROCEDURE FOR COMPRESSOR REPLACEMENT
1. Before connecting recovery/recycling recharging equipment to vehicle, check recovery/recycling recharg-
ing equipment gauges. No refrigerant pressure should be displayed. If NG, recover refrigerant from equip-
ment lines.
2. Connect recovery/recycling recharging equipment to vehicle. Confirm refrigerant purity in supply tank
using recovery/recycling recharging equipment and refrigerant identifier. If NG, refer to AT C - 7 , "
CONTAM-
INATED REFRIGERANT" .
3. Confirm refrigerant purity in vehicle A/C system using recovery/recycling recharging equipment and refrig-
erant identifier. If NG, refer to AT C - 7 , "
CONTAMINATED REFRIGERANT" .
4. Discharge refrigerant into the refrigerant recovery/recycling equipment. Measure lubricant discharged into
the recovery/recycling equipment.
5. Drain the lubricant from the old (removed) compressor into a graduated container and recover the amount
of lubricant drained.
6. Drain the lubricant from the new compressor into a separate, clean container.
7. Measure an amount of new lubricant installed equal to amount drained from old compressor. Add this
lubricant to new compressor through the suction port opening.
8. Measure an amount of new lubricant equal to the amount recovered during discharging. Add this lubricant
to new compressor through the suction port opening.
9. If the liquid tank also needs to be replaced, add another 5 m (0.2 US fl oz., 0.2 Imp fl oz.) of lubricant at
this time.
Do not add this 5 m (0.2 US fl oz., 0.2 Imp fl oz.) of lubricant when replaces the compressor only.
Part replacedLubricant to be added to system
Remarks
Amount of lubricant
m (US fl oz., Imp fl oz.)
Evaporator 75 (2.5, 2.6) —
Condenser 35 (1.2, 1.2) —
Liquid tank 10 (0.3, 0.4) —
In case of refrigerant leak30 (1.0, 1.1) Large leak
—
Small leak
*1

ATC-28
LUBRICANT
Revision: 2007 April2007 M35/M45
RJIA3578E

AIR CONDITIONER CONTROL
ATC-29
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: 2007 April2007 M35/M45
AIR CONDITIONER CONTROLPFP:27500
Description of Air Conditioner LAN Control SystemNJS000G4
The LAN (Local Area Network) system consists of unified meter and A/C amp., mode door motors, air mix
door motors, upper ventilator door motor and intake door motor.
A configuration of these components is shown in the figure below.
System ConstructionNJS000G5
A small network is constructed between the unified meter and A/C amp., mode door motors, air mix door
motors, upper ventilator door motor and intake door motor. The unified meter and A/C amp. and motors are
connected by data transmission lines and motor power supply lines. The LAN network is built through the
ground circuits of each door motor.
Addresses, motor opening angle signals, motor stop signals and error checking messages are all transmitted
through the data transmission lines connecting the unified meter and A/C amp. and each door motor.
The following functions are contained in LCUs built into the mode door motors, the air mix door motors, the
upper ventilator door motor and the intake door motor.

Address

Motor opening angle signals

Data transmission

Motor stop and drive decision

Opening angle sensor (PBR function)

Comparison

Decision (Unified meter and A/C amp. indicated value and motor opening angle comparison)
RJIA4016E
RJIA4017E