Page 1817 of 2395

3. Capacity Control=NBHA0087S0203IRefrigerant pressure on suction side is low during high speed driving or when ambient or interior tempera-
ture is low.
IThe bellows expands when refrigerant pressure on the suction pressure side drops below approximately
177 kPa (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.
IThe 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
DESCRIPTION
V-6 Variable Displacement Compressor (Cont'd)
HA-18
Page 1818 of 2395
Component LayoutNBHA0012
RHA451G
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
DESCRIPTION
Component Layout
HA-19
Page 1819 of 2395

IntroductionNBHA0013AIR CONDITIONER LAN SYSTEM OVERVIEW CONTROL SYSTEMNBHA0013S01The LAN system consists of auto amp., air mix door motor and mode door motor.
A configuration of these components is shown in the diagram below.
RHA439G
FeaturesNBHA0014SYSTEM CONSTRUCTION (LAN)NBHA0014S08A small network is constructed between the auto amplifier, air mix door motor and mode door motor. The auto
amplifier and motors are connected by data transmission lines and motor power supply lines. The LAN net-
work is built through the ground circuits of the two motors.
Addresses, motor opening angle signals, motor stop signals and error checking messages are all transmitted
through the data transmission lines connecting the auto amplifier and two motors.
The following functions are contained in LCUs built into the air mix door motor and the mode door motor.
IAddress
IMotor opening angle signals
IData transmission
IMotor stop and drive decision
IOpening angle sensor (PBR function)
IComparison
IDecision (Auto amplifier indicated value and motor opening angle comparison)
RHA440GA
OperationNBHA0014S0801The auto amplifier receives data from each of the sensors. The amplifier sends air mix door and mode door
opening angle data to the air mix door motor LCU and mode door motor LCU.
The air mix door motor and mode door motor read their respective signals according to the address signal.
Opening angle indication signals received from the auto amplifier and each of the motor position sensors are
compared by the LCUs in each motor with the existing decision and opening angles. Subsequently, HOT/
COLD or DEFROST/VENT operation is selected. The new selection data is returned to the auto amplifier.
DESCRIPTION
Introduction
HA-20
Page 1820 of 2395

RHA441GA
Transmission Data and Transmission OrderNBHA0014S0802Amplifier data is transmitted consecutively to each of the door motors following the form shown in figure below.
Start: Initial compulsory signal sent to each of the door motors.
Address: Data sent from the auto amplifier is selected according to data-based decisions made by the air mix
door motor and mode door motor.
If the addresses are identical, the opening angle data and error check signals are received by the door motor
LCUs. The LCUs then make the appropriate error decision. If the opening angle data is normal, door control
begins.
If an error exists, the received data is rejected and corrected data received. Finally, door control is based upon
the corrected opening angle data.
Opening angle: Data that shows the indicated door opening angle of each door motor.
Error check: Procedure by which sent and received data is checked for errors. Error data is then compiled.
The error check prevents corrupted data from being used by the air mix door motor and mode door motor.
Error data can be related to the following problems.
IAbnormal electrical frequency
IPoor electrical connections
ISignal leakage from transmission lines
ISignal level fluctuation
Stop signal: At the end of each transmission, a stop operation, in-operation, or internal problem message is
delivered to the auto amplifier. This completes one data transmission and control cycle.
RHA442G
Air Mix Door Control (Automatic Temperature Control)NBHA0014S0803The air mix door is automatically controlled so that in-vehicle temperature is maintained at a predetermined
value by: The temperature setting, ambient temperature, in-vehicle temperature and amount of sunload.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
DESCRIPTION
Features (Cont'd)
HA-21
Page 1821 of 2395

Fan Speed ControlNBHA0014S0804Blower speed is automatically controlled based on temperature setting, ambient temperature, in-vehicle
temperature, intake temperature, amount of sunload and air mix door position.
With FAN switch set to ªAUTOº, the blower motor starts to gradually increase air flow volume.
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flow-
ing.
Intake Door ControlNBHA0014S0805The intake doors are automatically controlled by: The temperature setting, ambient temperature, in-vehicle
temperature, intake temperature, amount of sunload and ON-OFF operation of the compressor.
Outlet Door ControlNBHA0014S0806The outlet door is automatically controlled by: The temperature setting, ambient temperature, in-vehicle
temperature, intake temperature and amount of sunload.
Magnet Clutch ControlNBHA0014S0807The ECM controls compressor operation using input signals from the throttle position sensor and auto ampli-
fier.
Self-diagnostic SystemNBHA0014S0808The self-diagnostic system is built into the auto amplifier (LCU) to quickly locate the cause of problems.
DESCRIPTION
Features (Cont'd)
HA-22
Page 1822 of 2395
Overview of Control System=NBHA0015The control system consists of input sensors, switches, the automatic amplifier (microcomputer) and outputs.
The relationship of these components is shown in the diagram below:
RHA856H
Control OperationNBHA0016
RHA452GA
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
DESCRIPTION
Overview of Control System
HA-23
Page 1823 of 2395

RHA328HA
DISPLAY SCREENNBHA0016S01Displays the operational status of the system.
AUTO SWITCHNBHA0016S02The compressor, intake doors, air mix door, outlet doors, and blower speed are automatically controlled so
that the in-vehicle temperature will reach, and be maintained at the set temperature selected by the operator.
ECON SWITCHNBHA0016S03By pressing the ECON switch, the display should indicate ECON and the compressor always turns OFF. With
the compressor OFF, the system will not remove heat (cool) or de-humidify. The system will maintain the in-
vehicle temperature at the set temperature when the set temperature is above the ambient (outside) tempera-
ture. The system will set the intake doors to the outside air position.
TEMPERATURE SWITCH (POTENTIO TEMPERATURE CONTROL) WITHOUT NAVIGATION
SYSTEM
NBHA0016S04Increases or decreases the set temperature.
OFF SWITCHNBHA0016S05The compressor and blower are OFF, the intake doors are set to the outside air position, and the air outlet
doors are set to the foot (80% foot and 20% defrost) position.
FAN SWITCHNBHA0016S06Manually controls the blower speed. Four speeds are available for manual control (as shown on the display
screen):
low
, medium low, medium high, high
RECIRCULATION (REC) SWITCHNBHA0016S07OFF position: Outside air is drawn into the passenger compartment.
ON position: Interior air is recirculated inside the vehicle.
DEFROSTER (DEF) SWITCHNBHA0016S08Positions the air outlet doors to the defrost position. Also positions the intake doors to the outside air position.
MODE SWITCHNBHA0016S09Controls the air discharge outlets.
TEMPERATURE DIAL (POTENTIO TEMPERATURE CONTROL) WITH NAVIGATION SYSTEMNBHA0016S10Increases or decreases the set temperature.
AMB (AMBIENT) SWITCH (WITH NAVIGATION SYSTEM)NBHA0016S11Shows the ambient (outside) air temperature on the display screen for 5 seconds.
DESCRIPTION
Control Operation (Cont'd)
HA-24
Page 1824 of 2395
Discharge Air FlowNBHA0017
RHA043G
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
DESCRIPTION
Discharge Air Flow
HA-25