Mazda 6. Manual - part 88

CONTROL SYSTEM

U–25

A/C correction

•

When the A/C compressor is switched from A/C ON mode to OFF mode, the basic opening angle of the air mix
actuator is switched from the A/C ON mode opening angle to the A/C OFF mode opening angle. This prevents
a rise in airflow temperature. In addition, this correction retards the air mix actuator operation to prevent a
sudden drop in airflow temperature.

MAX HOT and MAX COLD correction

•

When the temperature is set to MAX HOT (temperature setting dial is turned to the right), air mix actuator is
completely open (100%), when set to MAX COLD (temperature setting dial is turned to the left), it is firmly
closed.

Coolant temperature correction

•

There are cases where the engine coolant temperature is lowered when continuously idling in extremely low
outside temperature. To prevent lower airflow temperature in this situation, the climate control unit adjusts the
HOT air mix actuator to opening according to the engine coolant temperature. However, coolant temperature
correction does not operate when the ambient temperature is above 10

C {50

F}.

A6E8540T002

Air mix actuator opening angle delay

A/C mode

Air mix actuator opening angle correction amount

HOT

COLD

Time

U–26

CONTROL SYSTEM

Fail-safe function

•

When the potentiometer of air mix actuator is malfunctioning, the air mix door is fixed. Under this situation, if
the ignition switch is turned to the ON/LOCK position, the air mix door is controlled to be fully opened (MAX
HOT) or closed (MAX COLD) based on the ambient temperature. In addition, the door is fully closed (MAX
COLD) at the set temperature MAX COLD (15.0: European (L.H.D. U.K.) specs. 18.0: GCC specs.), and fully
opened (MAX HOT) at the set temperature MAX HOT (29.0: European (L.H.D. U.K.) specs. 32.0: GCC specs.).

•

If the air mix door locks and the target air mix actuator opening angle is not reached within 20 seconds, the air
mix actuator drive signal is stopped to prevent burning the motor.

End Of Sie

AIRFLOW VOLUME CONTROL

A6E854001044T05

•

Airflow volume is controlled by the power MOS FET so that the passenger compartment temperature remains
at the target temperature (control computation value T2).

•

Control computation value T2 is the target temperature in the cabin set by the climate control unit based on
differences between set temperature and input temperature from the sensors.

A6E8540T003

Ambient temperature

MAX COLD

MAX HOT

A6E8540T043

Fan switch

Set temperature

Airflow mode

Ambient temperature

Cabin temperature

Sunlight intensity

Coolant temperature

Signals

Climate control unit

Output

Feedback

Power MOS FET

Operation

Blower motor

Airflow volume changes

CONTROL SYSTEM

U–27

Airflow Volume Automatic Control

•

Based on the set temperature, the ambient temperature, and sunlight intensity, the climate control unit
calculates the blower motor voltage characteristic (AUTO voltage). It compares the differences among this
voltage characteristic, and the target temperature (control computation value T2) and then determines the
voltage to be applied to the blower motor.

Correction
Coolant temperature correction (warm-up correction)

•

To prevent a large volume of cold air from blowing through the ventilation outlets when the engine is started in
winter, coolant temperature control links the blower motor voltage to the rise in engine coolant temperature.
However, coolant temperature correction does not operate when the defroster correction is running, when the
cabin temperature is above 20

C {68

F}, or when airflow is in VENT mode.

A6E8540T044

Transition period

Stable period

When cooling

When heating

Increases/decreases linearly with sunlight intensity

Blower motor applied voltage characteristic

Blower motor applied voltage

Control computain value T2

MAX-HI

MIDDLE-HI

AUTO-HI

A6E8540T004

Rise to auto voltage

Blower motor applied voltage

Coolant temperature

Low

High

U–28

CONTROL SYSTEM

Mild start correction

•

To prevent a large volume of warm air from blowing through the ventilation outlets when the blower motor is
started in summer, the voltage applied to the blower motor is restricted for 3 seconds after it starts. However,
mild start correction does not operate when the passenger compartment temperature is below 20

C {68

F}, or

when airflow is in any mode other than VENT.

MAX HOT and MAX COLD correction

•

When the temperature is set to 29.0 (European (L.H.D. U.K.) specs.) or 32.0 (GCC specs.), the applied voltage
of the blower motor is set at AUTO-HI, when at 15.0 (European (L.H.D. U.K.) specs.) or 18.0 (GCC specs.), the
applied voltage of the blower motor is set at MAX-HI. However, when in water temperature correction, MAX
HOT correction does not take place.

Windshield mist prevention correction

•

To prevent the air blown from the defroster when the heater is started in winter from clouding the windows, the
blower motor and the A/C signal output are switched off for 6 seconds after the ignition is turned to the ON
position. This control only operates if the airflow is in HEAT, HEAT/DEF, or DEFROSTER mode.

Start compensation correction

•

When the blower motor is started at 3.2 V, it is run at a voltage of 4.4 V for 2 seconds to help it stabilize at the
target voltage.

Defroster correction

•

To improve defrosting and heating, 2.0 V is added to the AUTO voltage calculated airflow volume automatic
control when the defroster switch is turned on.

Fail-safe function

•

If the blower motor is started with more than 4.4 V, a surge will occur and the motor may burn. To prevent this,
the voltage applied to the blower motor is regulated to 4.4 V for 1 second when it is started.

A6E8540T005

Rises to auto voltage

Blower motor applied voltage

Time

Correction

Set temperature

Blower motor applied voltage

MAX HOT

29.0 (European (L.H.D. U.K.) specs.)

32.0 (GCC specs.)

12.1 (V): AUTO-HI

MAX COLD

15.0 (European (L.H.D. U.K.) specs.)

18.0 (GCC specs.)

B+: MAX-HI

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