System Description

DESCRIPTION

When the compressor activation condition is satisfied while blower motor is activated, A/C auto amp. transmits A/C ON signal and blower fan ON signal to ECM via CAN communication line.
ECM judges the conditions of each sensor (Refrigerant pressure sensor signal, accelerator position signal, etc.), and transmits the A/C compressor request signal to IPDM E/R via CAN communication line.
By receiving the A/C compressor request signal from ECM, IPDM E/R turns the A/C relay to ON, and activates the compressor. Refer to System Description .

CONTROL BY A/C AUTO AMP.

Low Temperature Protection Control

When intake sensor detects that evaporator fin temperature is [-5.0°C (23.0°F)] or less, A/C auto amp. requests ECM to turn the compressor OFF, and stops the compressor.

Courtesy of NISSAN NORTH AMERICA, INC.

When the air temperature returns to [1.0°C (33.8°F)] or more, the compressor is activated.

NOTE: Target temperature upper limit value of evaporator can be changed using "TARGET EVAPORATOR TEMP UPPER LIMIT SETTING" in "WORK SUPPORT" mode of CONSULT. Refer to Diagnosis Description .

Refrigerant Discharge Amount Control

When setting temperature is full cold or air outlet is other than DEF, A/C auto amp. controls the refrigerant discharge amount by adjust the duty ratio of ECV according to required amount of cooling capacity.
When evaporator temperature is target temperature upper limit value or more, A/C auto amp. increases the discharge amount.
When evaporator temperature is less than target temperature upper limit value, A/C auto amp. reduces the discharge amount.

NOTE: Target temperature upper limit value of evaporator can be changed using "TARGET EVAPORATOR TEMP UPPER LIMIT SETTING" in "WORK SUPPORT" mode of CONSULT. Refer to Diagnosis Description .

Compressor Oil Circulation Control

When the engine starts, A/C auto amp. activates the compressor for a few seconds and circulates the compressor oil once.

CONTROL BY ECM

Compressor Protection Control at Pressure Malfunction

The high-pressure side value that is detected by refrigerant pressure sensor is as per the following state, ECM requests IPDM E/R to turn A/C relay OFF and stop the compressor.

3.12 MPa (31.82 kg/cm2, 452.4 psi) or more (When the engine speed is less than 1, 500 rpm)
2.74 MPa (27.95 kg/cm2, 397.3 psi) or more (When the engine speed is 1, 500 rpm or more)
0.12 MPa (1.22 kg/cm2, 17.4 psi) or less

Air Conditioning Cut Control

When the engine condition is high load, ECM makes the A/C relay to OFF, and stops the compressor.