Nissan Primera P11. Instruction — part 484
A/C SWITCH COMPENSATION
The auto amplifier alters the air mix door position and air flow volume according to a signal emitted from the
A/C switch.
When the A/C switch is “ON”, the auto amplifier compensates for the PBR’s input signal and moves the air
mix door toward the “HOT” side.
YHA297
A/C control panel PTC
In-vehicle sensor
Ambient sensor
Sunload sensor
Sunload compensation
Auto amplifier
Air mix door position arith-
metic circuit
Output signal pro-
cess
Air mix door
motor
PBR
A/C control panel
A/C switch
KHA115
Air
mix
door
opening
ratio
(%)
100
15
0
Air mix door position arithmetic value
A/C switchcompensation specifications
0
100
(%)
SYSTEM DESCRIPTION
AUTO
Control System Auto Amplifier (Auto amp.)
(Cont’d)
HA-89
Control System Output Components
AIR MIX DOOR CONTROL (Automatic temperature control)
Component parts
Air mix door control system components are:
1) Auto amplifier
2) Ambient sensor
3) In-vehicle sensor
4) Sunload sensor
5) Air mix door motor (PBR)
6) A/C switch
System operation
The air mix door is automatically controlled so that in-vehicle temperature is maintained to the set tempera-
ture. The temperature set by the PTC (Potentio Temperature Control) and the temperature detected by the
in-vehicle sensor and ambient sensor are compensated by the sunload sensor signal. The auto amplifier then
determines the air mix door position. The air mix door position detected by the PBR is compensated by the
ON-OFF operation of the A/C switch. The air mix door position determined by the auto amplifier is compared
with that detected by the PBR. The auto amplifier then transmits the signal to the air mix door motor in order
to activate it.
KHA116
Auto amplifier
PTC
In-vehicle sensor
Ambient
sensor
sunload
sensor
PBR
A/C switch
Constant voltage
transformation
Air mix door posi-
tion arithmetic cir-
cuit
Sunload compen-
sation
Air mix door posi-
tion detection
A/C switch com-
pensation
Air mix
door motor
SYSTEM DESCRIPTION
AUTO
HA-90
Air mix door control specifications
SENSOR INPUT PROCESS
The auto amplifier detects the voltage produced by each sensor,
the PBR and fixed resistor. The fixed resistor is built into the auto
amplifier. 12-volt power voltage is first converted to approxi-
mately 5 volts by the constant voltage circuit where it is then
applied to the ground line of the auto amplifier via the fixed
resistor and the sensor. In this manner, the auto amplifier moni-
tors the voltages of the fixed resistor, each sensor and the PBR
to determine sensor input.
SHA497CB
A/C switch OFF
A/C switch ON
V
oltage
(V)
Condition
PTC: 25°C (77°F)
Fan switch Auto
Withoutsunload
Ambient
temperature °C (°F)
Air mix door opening angle
In vehicle temperature °C (°F)
0.5
1.0
1.5
2.0
2.5
3.0
PBRresistance (k
Ω
)
2.4
2.3
2.2
2.1
2.0
1.9
(59)
(68)
(77)
(86)
(95)
(104)
-20 (-4)
-10 (-4)
0 (32)
10(50)
20 (68)
25 (77)
30(86)
40 (104)
54.5
RHA790A
Auto amplifier
Constant-voltage
circuit
Fixed resistor
Detection of sen-
sor voltage
Each sensor
SYSTEM DESCRIPTION
AUTO
Control System Output Components (Cont’d)
HA-91
OPERATION OF AIR MIX DOOR MOTOR
●
Example
p
1
When the temperature in the vehicle is lower than the set
temperature.
When the temperature in the vehicle is low, in-vehicle sen-
sor resistance is great and the input voltage to the auto
amplifier becomes great. As a result, the voltage from the air
mix door position arithmetic circuit also becomes great.
When this voltage is greater than the voltage from the PBR,
comparator (1), Tr
p
1
and Tr
p
4
turn ON.
Accordingly terminal No.
p
12
becomes
!
and terminal No.
p
13
becomes
@
. The air mix door motor rotates clockwise and
the air mix door moves toward the “HOT” side.
As the air mix door moves toward the “HOT” side, the volt-
age from the PBR becomes greater and consequently
becomes equal to that from the air mix door position arith-
metic circuit. As a result, comparator (1) turns OFF and the
air mix door motor stops.
RHA514DB
Auto amp.
Comparator
(1)
Air mix door
position arith-
metic circuit
Air mix
door
motor
PBR
Comparator
(2)
SHA568CB
Auto amp.
Comparator
(1)
Air mix door
position
arithmetic
circuit
PBR
Comparator
(2)
Air mix
door
motor
SYSTEM DESCRIPTION
AUTO
Control System Output Components (Cont’d)
HA-92
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст