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Nissan Leaf. Manual - part 757

SYSTEM

HAC-31

< SYSTEM DESCRIPTION >

[AUTO A/C (WITH HEAT PUMP)]

HAC

• The automatic air conditioning system is controlled by the control functions of the A/C auto amp., VCM, AV

control unit, heat pump control unit and TCU.

• The A/C system operations are input from the A/C auto amp. switches (A/C control).

• The A/C auto amp. sends various display information to VCM via EV CAN communication.

• VCM sends information received from the A/C auto amp. to the AV control unit via EV CAN communication.

• AV control unit displays the A/C status on the display, based on the information received from VCM.

• A/C auto amp. transmits each type of request signals to PTC heater, electric compressor and heat pump

control unit via LIN communication for controlling the PTC heater, electric compressor and heat pump sys-

tem.

CONTROL BY A/C AUTO AMP.

•

HAC-32, "AUTOMATIC AIR CONDITIONING SYSTEM : Temperature Control"

•

HAC-32, "AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control"

•

HAC-32, "AUTOMATIC AIR CONDITIONING SYSTEM : Air Flow Control"

•

HAC-33, "AUTOMATIC AIR CONDITIONING SYSTEM : Air Inlet Control"

•

HAC-34, "AUTOMATIC AIR CONDITIONING SYSTEM : Compressor Control"

•

HAC-35, "AUTOMATIC AIR CONDITIONING SYSTEM : Door Control"

•

HAC-37, "AUTOMATIC AIR CONDITIONING SYSTEM : PTC Heater Control"

•

HAC-37, "AUTOMATIC AIR CONDITIONING SYSTEM : Heat Pump System Control"

• Cooling fan control: A/C auto amp. calculates the necessary cooling fan speed during air conditioner opera-

tion, and requests the cooling fan operation by transmitting the cooling fan speed request signal via EV CAN

communication to VCM. For details of cooling fan control, refer to

EVC-53, "HIGH VOLTAGE SYSTEM

COOLING CONTROL : System Description"

• Input data processing

- Ambient temperature correction

• The A/C auto amp. inputs the temperature detected with the ambient sensor as the ambient temperature.

• The A/C auto amp. internally processes the ambient temperature data is two data types: data for A/C control

and data for ambient temperature display.

• When the vehicle speed is 30 km/h or less, if the effects of radiator heat and other factors result in a sudden

increase in detected ambient temperature, the A/C auto amp. performs delay correction so that the recog-

nized temperature rises slowly. Correction is performed so that the change is recognized quickly when the

ambient temperature drops.

• When the temperature detected by the ambient sensor is less than approximately –20

°C, no correction is

performed for the data for A/C control.

• When the temperature detected by the ambient sensor is less than approximately –29

°C, no correction is

performed for the data for ambient temperature display.

- Interior air temperature correction

• The A/C auto amp. inputs the temperature detected by the in-vehicle sensor as the interior air temperature.

• In order to prevent effects from uneven temperatures inside the vehicle and from external disruptions, the A/

C auto amp. performs correction so that the recognized interior air temperature changes slowly. The A/C

auto amp. performs the correction so that the recognized interior temperature changes according to the dif-

ference between the detected interior temperature and the recognized interior temperature. If the difference

is large, the changes occur quickly, and becomes slower as the difference becomes smaller.

- Intake temperature correction

• The A/C auto amp. inputs the temperature detected with the intake sensor as the air temperature after pass-

ing through the evaporator.

• In order to prevent effects from uneven intake temperatures and from external disruptions, the A/C auto

amp. performs correction so that the recognized intake air temperature changes slowly. The A/C auto amp.

performs the correction so that the recognized intake temperature changes according to the difference

between the detected intake temperature and the recognized intake temperature. If the difference is large,

the changes occur quickly, and becomes slower as the difference becomes smaller.

- Sunload amount correction

• The A/C auto amp. inputs the sunload detected by the sunload sensor.

• When the sunload suddenly changes, for example when entering and leaving a tunnel, correction is per-

formed so that the recognized sunload of the A/C auto amp. changes slowly.

- Set temperature correction

The A/C auto amp. controls the interior temperature so that it is always at the optimum level, and performs

correction so that the temperature felt by the passengers matches the target temperature set with the tem-

perature control switch, according to the ambient temperature detected by the ambient sensor.

CONTROL BY VCM

HAC-32

< SYSTEM DESCRIPTION >

[AUTO A/C (WITH HEAT PUMP)]

SYSTEM

For details of cooling fan control, refer to

EVC-53, "HIGH VOLTAGE SYSTEM COOLING CONTROL : System

Description"

AUTOMATIC AIR CONDITIONING SYSTEM : Temperature Control

INFOID:0000000010121752

• When power switch is in the ON position, A/C auto amp. always

automatically controls temperature regardless of air conditioner

operational state.

• A/C auto amp. calculates the target air mix door opening angle

according to set temperature, in-vehicle temperature, ambient tem-

perature, and sunload.

• Air mix door is controlled according to the comparison of current air

mix door opening angle and target air mix door opening angle.

• Regardless of in-vehicle temperature, ambient temperature, and

sunload, air mix door is fixed at the fully cold position when set

temperature is 16.0

°C, and at the fully hot position when set tem-

perature is 30.0

°C.

AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control

INFOID:0000000010121753

• While air outlet is in automatic control, A/C auto amp. selects the

mode door position depending on a target air mix door angle and

outlet air temperature calculated from sunload.

• When FOOT is set for the air outlet, the outlet is set to D/F to pre-

vent windshield fogging only when the ambient temperature is

extremely low (

−13°C or less).

• When the ON/OFF switch is pressed during air conditioner opera-

tion, the air outlet is fixed at the position where the ON/OFF switch

is pressed.

AUTOMATIC AIR CONDITIONING SYSTEM : Air Flow Control

INFOID:0000000010121754

DESCRIPTION

• A/C auto amp. changes gate voltage to power transistor and controls air flow continuously based on target

air flow. When air flow is to be increased, voltage to blower fan motor increases gradually for preventing a

sudden increase of air flow.

AUTOMATIC AIR FLOW CONTROL

• A/C auto amp. determines target air flow according to target air mix door opening angle.

• A/C auto amp. changes voltage to power transistor gate and controls air flow in a continuous range (no

steps) so that target air flow is achieved. At this time, the voltage applied to the blower fan motor is changed

at the rate of 1.0 V per second in order to prevent any sudden changes in air flow.

• When air outlet is VENT or B/L, the minimum air flow is changed

depending on sunload.

STARTING AIR FLOW CONTROL

JPIIA0633GB

JMIIA0710GB

JMIIA1129GB

SYSTEM

HAC-33

< SYSTEM DESCRIPTION >

[AUTO A/C (WITH HEAT PUMP)]

HAC

When blower fan motor is activated, A/C auto amp. changes the volt-

age to the power transistor gate, and gradually increases the voltage

to the blower fan motor, in order to prevent a sudden increase in dis-

charge air flow (approximately 10.5 seconds for air flow to reach HI

from LOW).

NOTE:

When outlet is DEF, air flow control at motor start is not performed.

AUTO MODE STARTING AIR FLOW CONTROL

When the blower fan motor is activated by the AUTO control, voltage

to blower fan motor increases gradually and then the amount of air

flow increases gradually. (Approximately 138 seconds for air flow to

reach HI from LOW)

STARTING AIR FLOW CONTROL AT HIGH INTERIOR AIR TEMPERATURE

When evaporator temperature is high [intake air temperature sensor value is 35

°C (95°F) or more], to prevent

a hot discharged air flow, A/C auto amp. suspends blower motor activation for approximately three seconds so

that evaporator is cooled by refrigerant.

AIR FLOW CONTROL AT MODE DOOR MOTOR OPERATION

If the mode motor starts when the air flow corresponds to a voltage of 8.6 V or more applied to the blower fan

motor, the A/C auto amp. performs control that fixes the voltage applied to the blower fan motor at 8.5 V, tem-

porarily decreasing the air flow and ensuring that the mode door operates smoothly.

MANUAL AIR FLOW CONTROL

When the fan switch is operated, automatic control is cancelled and the desired fan speed (1 – 7) can be

selected.

AUTOMATIC AIR CONDITIONING SYSTEM : Air Inlet Control

INFOID:0000000010121755

• Manual control by the intake switch is given priority for inlet selection.

• When the DEF switch is pressed, the inlet is fixed at fresh air intake.

• During automatic inlet control, when the electric compressor is ON and the ambient temperature is high, the

intake is fixed at recirculation.

• When the A/C system is OFF, the inlet is fixed at fresh air intake.

JMIIA1130GB

JSIIA1775GB

Voltage applied to blower fan motor (V)

Mode switch

VENT, B/L

FOOT, D/F

DEF

Fan speed
(When manual
control is selected)

1st

4.0

2nd

5.4

5.2

5.3

3rd

6.8

6.3

6.7

4th

8.3

7.5

8.0

5th

9.7

8.7

9.3

6th

11.1

9.8

10.7

7th

12.5

11.0

12.5

HAC-34

< SYSTEM DESCRIPTION >

[AUTO A/C (WITH HEAT PUMP)]

SYSTEM

• Other than the above, during automatic inlet control the A/C auto amplifier switches the intake control status

according to the A/C ON/OFF judgment status (A/C switch indicator lamp status), amount of discharged air,

outlet operating status and ambient temperature.

AUTOMATIC AIR CONDITIONING SYSTEM : Electric Power Distribution Control

INFOID:0000000010121756

DESCRIPTION

• Based on the vehicle status, battery remaining energy, and other factors, VCM calculates the electrical

power needed to operate the A/C system, and sends this value to the A/C auto amp. via EV CAN communi-

cation.

• Based on the ambient sensor signal, inlet position, outlet position, target air mix door position, and other

information, the A/C auto amp. calculates the electrical power used by the electric compressor and PTC ele-

ment heater. If the total exceeds the electric power consumption permitted by the VCM, then the operating

rate of the electric compressor and PTC element heater are reduced to lower the power consumption.

WARM-UP AND COOL-DOWN CONTROL

For the first 10 minutes after the power switch is turned ON, heating/cooling operation at maximum capacity is

possible based on a judgment by the A/C auto amp. (however this does not occur in ECO mode).

AUTOMATIC AIR CONDITIONING SYSTEM : Compressor Control

INFOID:0000000010121757

DESCRIPTION

• When the conditions for electric compressor operation are met while the blower fan motor is operating, then

based on the various input signals, the A/C auto amplifier calculates the electric compressor target speed

that produces the target temperature [cooler (dehumidified) mode: 4 to 12°C, heater mode: target outlet tem-

perature + corrected temperature value*] for the evaporator outlet temperature [cooler (dehumidified) mode]

or the inner condenser temperature (heater mode). It then sends a speed request signal to the electric com-

pressor via LIN communication and commands the speed.

NOTE:

*: The corrected temperature during heater mode is calculated by the A/C auto amplifier according to the

ambient temperature.

• The electric compressor receives the A/C auto amp. command and controls the motor speed by means of its

built-in inverter circuit, then transmits this status by LIN communications.

Evaporator Protection Control

A/C ON/OFF judg-

ment status (A/C

switch indicator lamp

status)

Mode

switch

Ambient temperature (temperature detected by ambient sensor)

°C or less

°C or more

VENT

B/L

30% recirculation

Control according to the target air mix door position

FOOT

D/F

Fresh air intake

OFF

VENT

B/L

30% recirculation

Fresh air intake

FOOT

D/F

Fresh air intake

JMIIA0711GB

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