Infiniti FX35 / FX45. Manual - part 105

 

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Infiniti FX35 / FX45. Manual - part 105

 

 

ATC-16

< SERVICE INFORMATION >

PREPARATION

Commercial Service Tool

INFOID:0000000001328161

Service couplers
• High-pressure side coupler

(J-39500-20)

• Low-pressure side coupler

(J-39500-24)

Hose fitting to service hose:
M14 x 1.5 fitting is optional or perma-
nently attached.

(J-39650)
Refrigerant weight scale

For measuring of refrigerant
Fitting size: Thread size

1/2

-16 ACME

(J-39649)
Vacuum pump
(Including the isolator valve)

Capacity:
• Air displacement: 4 CFM
• Micron rating: 20 microns
• Oil capacity: 482 g (17 oz.)
Fitting size: Thread size

• 1/2

-16 ACME

Tool number

(Kent-Moore No.)

Tool name

Description

S-NT202

S-NT200

S-NT203

Tool name

Description

Refrigerant identifier equipment

Checking for refrigerant purity and 
system contamination

Power tool

For loosening bolts and nuts

RJIA0197E

PBIC0190E

REFRIGERATION SYSTEM

ATC-17

< SERVICE INFORMATION >

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REFRIGERATION SYSTEM

Refrigerant Cycle

INFOID:0000000001328162

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 auto amp. will make the A/C relay go OFF and stop the compressor.

Refrigerant System Protection

INFOID:0000000001328163

REFRIGERANT PRESSURE SENSOR

The refrigerant system is protected against excessively high- or low-pressure by the refrigerant pressure sen-
sor, located on the condenser. If the system pressure rises above, or falls below the specifications, the refrig-
erant 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 2,746 kPa (28 kg/cm

2

, 398 psi), or below about 134 kPa

(1.4 kg/cm

2

, 20 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 3,727 kPa (38 kg/
cm

2

, 540 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into

the atmosphere.

V-6 Variable Displacement Compressor

INFOID:0000000001328164

GENERAL INFORMATION

1.

The V-6 variable compressor differs from previous units. The outlet air temperatures of the V-6 variable
compressor do not drop too far below 5

°

C (41

°

F) when:

RJIA0849E

ATC-18

< SERVICE INFORMATION >

REFRIGERATION SYSTEM

Evaporator intake air temperature is less than 20

°

C (68

°

F).

Engine is running at speeds less than 1,500 rpm.
This is because the V-6 compressor provides a means of “capacity” control.

2.

The V-6 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
conditioning systems.

3.

A “clanking” sound may occasionally be heard during refrigerant charge. The sound indicates that the tilt
angle of the wobble (swash) plate has changed and is not a malfunction.

4.

For air conditioning systems with the V-6 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.

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 wobble (swash) plate allows the piston’s stroke to change so that refrigerant discharge continu-
ously change from 14.5 to 184 cm

3

 (0.885 to 11.228 cu in).

RJIA1260E

REFRIGERATION SYSTEM

ATC-19

< SERVICE INFORMATION >

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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 wobble (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 wobble (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 journal pin near the wobble (swash) plate, and is generated by the pressure dif-
ference before and behind the piston.

-

The drive lug and journal pin are located where the piston generates the highest pressure. Piston pres-
sure is between suction pressure Ps and discharge pressure Pd, which is close to suction pressure Ps. If
crankcase pressure Pc rises due to capacity control, the force around the journal pin makes the wobble
(swash) plate angle decrease and also the piston stroke decrease. In other words, crankcase pressure

SJIA0547E

 

 

 

 

 

 

 

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