Infiniti M35/M45 Y50. Manual - part 118

REFRIGERATION SYSTEM

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ATC

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

sure difference between the piston and the crankcase. The pressure difference changes the angle of the
swash plate.

SJIA0548E

REFRIGERATION SYSTEM

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ATC

Component Layout

NJS000G2

SJIA1785E

ATC-26

LUBRICANT

LUBRICANT

PFP:KLG00

Maintenance of Lubricant Quantity in Compressor

NJS000G3

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

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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 

ATC-27, "LUBRICANT ADJUSTING PROCEDURE FOR COMPRESSOR REPLACE-

MENT"

 .

NO

>> GO TO 

ATC-27, "LUBRICANT ADJUSTING PROCEDURE FOR COMPONENTS REPLACE-

MENT EXCEPT COMPRESSOR"

 .

Name

: Nissan A/C System Oil Type S