FRONT AUTOMATIC AIR CONDITIONING SYSTEM : System Description

WARNING: This page is about a different car, the 2011 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.

SYSTEM DIAGRAM

Fig 1: Front Automatic Air Conditioning System Description

Courtesy of NISSAN MOTOR CO., U.S.A.

DESCRIPTION

Front automatic air conditioning system is controlled by each function of A/C auto amp., BCM, ECM and IPDM E/R.
Each operation of front air conditioning system can be controlled by front A/C control (built-in A/C auto amp.).

CONTROL BY A/C AUTO AMP.

Ambient temperature correction

A/C auto amp. inputs the temperature detected by ambient sensor as the ambient temperature.
A/C auto amp. performs the correction of the temperature detected by ambient sensor for front air conditioning control.
A/C auto amp. selects and uses the initial value of ambient temperature data depending on the engine coolant temperature when turning the ignition switch from OFF to ON. The detection temperature of the ambient sensor is used when engine coolant temperature is low [less than approximately 56°C (133°F)]. The memory data (before the ignition switch is OFF) when the engine is warmed up [approximately 56°C (133°F) or more].
The correction of the ambient temperature is not performed when the detection temperature of the ambient temperature is less than approximately -20°C (-4°F).

Front in-vehicle temperature correction

A/C auto amp. inputs the temperature detected by front in-vehicle sensor as the front in-vehicle temperature.
A/C auto amp. performs the correction of the temperature detected by front in-vehicle sensor for front air conditioning control.
A/C auto amp. performs the correction so that the recognition passenger room temperature (front side) changes depending on the difference between the detected passenger room temperature (front side) and the recognition passenger room temperature (front side). If the difference is large, the changing is early. The changing becomes slow as the difference becomes small.

Intake temperature correction

A/C auto amp. inputs the temperature detected by intake sensor as the intake temperature (front evaporator temperature).
A/C auto amp. performs the correction of the temperature detected by intake sensor for front air conditioning control.
A/C auto amp. performs the correction so that the recognition intake temperature changes depending on the difference between the detected intake temperature and the recognition intake temperature. If the difference is large, the changing is early. The changing becomes slow as the difference becomes small.

Sunload amount correction

A/C auto amp. inputs the sunload amount detected by sunload sensor.
A/C auto amp. performs the correction of the sunload amount detected by sunload sensor for front air conditioning control.
When the sunload amount suddenly changes, for example when entering a tunnel, perform the correction so that the recognition sunload amount of the A/C auto amp. changes slowly.

Set temperature correction

A/C auto amp. performs the correction to the target temperature set by the temperature control switch so as to match the temperature felt by the passengers depending on the ambient temperature detected by ambient sensor and controls it so that the in-vehicle temperature is always the most suitable.

CONTROL BY BCM

"FRONT AUTOMATIC AIR CONDITIONING SYSTEM : COMPRESSOR CONTROL "

CONTROL BY ECM

"FRONT AUTOMATIC AIR CONDITIONING SYSTEM : COMPRESSOR CONTROL "
Cooling fan control. Refer to "COOLING FAN CONTROL : SYSTEM DESCRIPTION ".

CONTROL BY IPDM E/R

"FRONT AUTOMATIC AIR CONDITIONING SYSTEM : COMPRESSOR CONTROL "
Cooling fan control. Refer to "RELAY CONTROL SYSTEM : SYSTEM DESCRIPTION ".