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Nissan Leaf. Manual - part 806

COMPONENT PARTS

HAC-227

< SYSTEM DESCRIPTION >

[AUTO A/C (WITHOUT HEAT PUMP)]

HAC

• A scroll-type compressor is used. The motor drive force is used to rotate the moveable scroll and perform

refrigerant intake, compression, and discharge.

PTC Heater

INFOID:0000000010121940

• A PTC heater is used as the heat source for heating.

• Provides internal control circuit and performs LIN communication

with A/C auto amp.

• Based on the signals from A/C auto amp., the microcomputer

inside PTC heater controls the heater output by PWM

Note

NOTE:

• PWM (Pulse Width Modulation) is a system that controls current

and voltage by changing the duty ratio of a constant frequency

pulse wave.

• PWM is used as the adjustment method of output voltage when

inverter is used as a power supply for controlling motor speed.

• PWM changes voltage application time (pulse width) using a

semiconductor element and controls PTC heater.

• PTC stands for “Positive Temperature Coefficient”, and is a ceramic material with barium titanate as the pri-

mary component.

• When current is applied, it heats up. Upon reaching a certain tem-

perature (Curie temperature) the resistance suddenly increases,

limiting the current, and maintaining a constant amount of heating.

JSIIA1625GB

JMIIA2741ZZ

JSIIA1653GB

HAC-228

< SYSTEM DESCRIPTION >

[AUTO A/C (WITHOUT HEAT PUMP)]

SYSTEM

SYSTEM

AUTOMATIC AIR CONDITIONING SYSTEM
AUTOMATIC AIR CONDITIONING SYSTEM : System Description

INFOID:0000000010121941

SYSTEM DIAGRAM

DESCRIPTION

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

AV control unit.

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

• 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.

CONTROL BY A/C AUTO AMP.

•

HAC-229, "AUTOMATIC AIR CONDITIONING SYSTEM : Temperature Control"

•

HAC-230, "AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control"

•

HAC-230, "AUTOMATIC AIR CONDITIONING SYSTEM : Air Flow Control"

•

HAC-231, "AUTOMATIC AIR CONDITIONING SYSTEM : Air Inlet Control"

JSIIA1781GB

SYSTEM

HAC-229

< SYSTEM DESCRIPTION >

[AUTO A/C (WITHOUT HEAT PUMP)]

HAC

•

HAC-232, "AUTOMATIC AIR CONDITIONING SYSTEM : Compressor Control"

•

HAC-235, "AUTOMATIC AIR CONDITIONING SYSTEM : PTC Heater Control"

• 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

• For details of cooling fan control, refer to

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

tem Description"

AUTOMATIC AIR CONDITIONING SYSTEM : Temperature Control

INFOID:0000000010121942

• 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.

JPIIA0633GB

HAC-230

< SYSTEM DESCRIPTION >

[AUTO A/C (WITHOUT HEAT PUMP)]

SYSTEM

AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control

INFOID:0000000010121943

• 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:0000000010121944

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

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

JMIIA0710GB

JMIIA1129GB

JMIIA1130GB

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