Nissan Primera P11. Manual — part 466
3. Capacity control
●
Refrigerant pressure on suction side is low during high speed driving or when ambient or interior tem-
perature is low.
●
The bellows expands when refrigerant pressure on the suction pressure side drops below approximately
177 kPa (1.77 bar, 1.8 kg/cm
2
, 26 psi).
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 swash plate, and is generated by the pressure difference
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 near suction pressure Ps. If
crankcase pressure Pc rises due to capacity control, the force around the journal pin makes the swash
plate angle decrease and also the piston stroke decrease. In other words, crankcase pressure increase
triggers pressure difference between the piston and the crankcase. The pressure difference changes the
angle of the swash plate.
RHA474C
Discharge port
Suction port
Crankcase
Low-pressure valve: Open
Valve position for lowering
crankcase pressure
Spring pressure
Cylinder pres-
sure
Crankcase pres-
sure
Forces needed to increase stroke
DESCRIPTION
CSV613 Variable Displacement Compressor
(Cont’d)
HA-17
Component Layout
KHA104
Side defroster nozzle
Defroster nozzle
Side defroster nozzle
Side ventilator duct
Center ventilator duct
Intake unit
Control assembly
(Heater)
Cooler unit
Fresh vent
control lever
Heater unit
Side ventilator duct
For Scandinavian models only:
Rear heater duct
(Whenremoving rear heater
duct, it is necessary
to remove frontseats.)
SEC. 270
⋅
271
⋅
272
⋅
273
Control assembly
(Air conditioner)
DESCRIPTION
HA-18
Control Operation
FAN CONTROL KNOB
This knob turns the fan ON and OFF, and controls fan speed.
MODE CONTROL KNOB
This knob controls the outlet air flow.
TEMPERATURE CONTROL KNOB
This knob allows adjustment of the temperature of the outlet air.
RECIRCULATION (REC) SWITCH
OFF position:
Outside air is drawn into the passenger compartment.
ON position:
Interior air is recirculated inside the vehicle.
The indicator lamp will also light.
Air Flow
FRESH VENT SYSTEM
This system is controlled by means of the fresh air vent lever which is mechanically linked to the fresh vent
door by the control cable.
Fresh vent air always comes from the center vent in any mode when the fresh air vent lever is set at the
blue dot position.
KHA105
Fan
control knob
Temperature
control knob
Mode
control knob
Mode
control knob
Temperature
control knob
Fan
control knob
Rear defroster
switch
Recirculation
switch
.
Rear defroster
switch
Recirculation
switch
LHD models
RHD models
KHA064
Fresh air vent
control lever
Set at blue dot position
To defroster
Heater core
Evaporator
Outside air
To floor
To floor
Fresh air vent con-
trol cable
DESCRIPTION
HEATER
HA-19
Introduction
The automatic temperature control (ATC) system provides automatic regulation of the discharged air tem-
perature and the discharged air volume (Blower speed).
The air outlet door, intake door and compressor magnet clutch are controlled by the manual operation of
each switch.
Features
Air mix door control (Automatic temperature control)
The air mix door is automatically controlled so that in-vehicle temperature will reach, and be maintained at
the operator selected “set temperature”. For a given set temperature, the air mix door position will depend
on: Ambient temperature, in-vehicle temperature, amount of sunload, set temperature and A/C switch sig-
nals.
Fan speed control
When the fan control switch is in the Auto position, the blower speed is automatically controlled, depending
on: Ambient temperature, in-vehicle temperature, amount of sunload, set temperature, and A/C switch sig-
nals. It is also controlled by the manual operation of the fan control switch.
Starting fan speed control
When engine coolant temperature is low, the air outlet door position is detected by the A/C control panel
and if this is set in B/L, FOOT or FOOT/DEF blower speed is controlled to prevent a large amount of cold
air from being discharged into the floor area.
Outlet door control
This can be selected by operation of the mode control knob.
Intake door control
This can be selected by changing the REC switch position.
Compressor magnet clutch control
System with CR-14 compressor
When the A/C switch is ON, the thermistor detects evaporator temperature. The thermo control amplifier
controls clutch ON/OFF operation depending on the evaporator temperature.
System with CSV613 compressor
Under normal operating conditions, when the A/C is switched on, the compressor runs continuously, and the
evaporator pressure, and therefore temperature, is controlled by the CSV613 variable displacement com-
pressor to prevent freeze up.
DESCRIPTION
AUTO
HA-20
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