E6020 Air conditioner (Automatic air conditioning)

Description

An automatic system manages the passenger compartment climate control, i.e. temperature and ventilation with recirculation and air flow orientation, with separate management of the temperature for the left and right hand sides of the passenger compartment.

A dedicated control unit manages system operation by controlling:

• air temperature at the driver/passenger vent;
• air distribution to the vents;
• speed of the fan (varies continuously);
• activation of the compressor (air refrigeration circuit);
• activation of air recirculation;
• The MAX-DEF fast defrost function (i.e. a set of actions which allow both the windscreen and the rearscreen to be demisted quickly);

The control unit sets the above parameters in order to adjust passenger compartment temperature to the required level. The system controls are located outside the control unit housing.

The following parameters/functions can be modified manually:

• fan speed
• distribution direction
• compressor disablement
• defrosting/demisting:
• recirculation

Manual selections always take precedence over automatic selections and are stored until the user deliberately cancels the command, allowing the automatic device to take control over the relevant function.

The control unit downloads information on interior and exterior temperature and climatic conditions via special sensors.

• exterior temperature sensor, locate on the driver's side door mirror. The sensor reading is downloaded by a control unit on the door and filtered as necessary; it is then sent via the CAN network to the climate control system ECU (to instrument panel and other appliances).
• lower mixed air temperature sensor (right and left);
• upper mixed air sensors (right and left);
• passenger compartment temperature sensor
• sunlight sensor, which measures the sun's rays on the windscreen;
• exhaust gas presence sensor (A.Q.S.: Air Quality Sensor):supplies a signal when the air pollution index exceeds a preset level of harmfulness. This signal turns on the recirculation to prevent polluted air entering the passenger compartment;
• demisting sensor, which detects the presence of water droplets (mist) on the inner surface of the windscreen; this information turns on the relevant demisting strategy., which alters the air and ventilation distribution pattern.

After processing the information, it adjusts passenger compartment air intake speed by means of the fan motor and air temperature by means of two mixer actuators (one for the right side and one for the left). it also sets flow distribution with another actuator and - lastly - interior air/exterior air recirculation via a final actuator.

When required, the ECU automatically activates the cooling circuit and dehumidifies the air by operating the air conditioner compressor Wiring diagram E6021 COMPRESSOR ACTIVATION .

For more details Characteristic of working principle 5040 Air conditioner box and components .

Note

Recirculation brings about closing of windows Wiring diagram E3050 FRONT WINDOW MECHANISM and sun roof Wiring diagram E3060 SUN ROOF . The air conditioning control unit downloads a signal from the gas presence sensor and activates the recirculation function to prevent polluted air from being taken into the passenger compartment. When normal conditions are restored, the climate control system ECU resets recirculation to the position prior to function activation. Because recirculation is activated under these conditions, a command is sent for automatic closure of the windows Wiring diagram E3050 FRONT WINDOW MECHANISM and sun roof Wiring diagram E3060 SUN ROOF .

The climate control system ECU receives a signal from the body computer to indicate that the windscreen washer is on and activates the recirculation function to prevent the liquid detergent smell from entering the passenger compartment.

The vehicle speed signal - received by the CAN network - is used to filter outdoor temperature and adjust ventilation and the dynamic air intake according to car speed.

The body computer continually downloads a battery voltage signal for comparison with its limit value. If the recorded battery voltage is lower than the threshold, the computer cuts in via the CAN network to send a signal to disable a series of appliances: this includes the fan control.

The climate control system ECU is supplied by an ignition-operated line protected by a fuse in the underfacia control unit; the fan is supplied by a line protected by a specific engine bay control unit fuse.

Description of operation

Climate control control unit M70 is supplied when the ignition is turned on (INT/A) at pin 25 of a line protected by fuse F31 from underfacia junction unit B2. ; it is supplied directly at pin 31 from a line protected by fuse F39 of underfacia control unit B2.

The supply for lighting the controls with the side lights on reaches pin 24 from the line protected by fuse F35 of underfacia control unit B2.

Pin 21 of M70 is earthed.

Control unit M70 is also connected to sensors K87 (right lower treated air - connector B - and left - connector A), K88 (right upper treated air - connector B - and left - connector A); these sensors receive a reference earth from pin 32 and send signals to pins 19, 20, 29 and 30 of M70.

Passenger comparment air sensorK89 also receives a reference earth from pin 32 and sends a signal to pin 37 of M70. Sensor K89 is fitted with a fan motor controlled by the ignition so that the temperature reading is not affected by the motionless and thus warmer air inside the dashboard.

The solar ray sensor K90 informs the control unit of the heat coming from rays: it receives a 5V supply from pin 38 control unit M70 and gives out two signals: to pin 39 for the right area and to pin 40 for the left area.

The exhaust gas presence sensor (A.Q.S.) K64 supplies a recirculation control signal when the air pollution exceeds pre-set levels: it is supplied at pin 1 from the line controlled by the ignition (INT/A) protected by fuse F31 of underfacia control unit B2. pin 2 is earthed and pin 3 sends a signal to pin 27 of M70.

Demisting sensor K03 is supplied at pin 2 of ignition-operated line (INT) protected by fuse F49 of underfacia control unit B2; Pin 1 is earthed and pin 3 sends a signal to pin 28 of M70.

The air conditioning system is equipped with one recirculation actuator (N82), two air blending actuators (N78 and N79) and two air districution actuators (N81 and N83).

Recirculation actuator N82 is controlled by control unit M70, via pins 1, 2, 3 and 4.

Mixing actuators N78 and N79 are controlled from control unit M70 via pins 5, 6, 7, 8 and 11, 12, 13 14 respectively.

Distribution actuator N80 is controlled from control unit M70 from pins 15, 16, 17 and 18.

An electronic governer controls fan N85 at different speeds via an earth command: this is ignition-operated (INT/A) from a line protected by fuse F31 of underfacia control unit B2. It receives a control signal from pin 33 of the control unit and returns a feedback signal to pin 9 of M70.

Fan N85 is supplied directly from a line protected by fuse F5 of engine bay control unit B1.

Pin 36 of M70 controls activation of compressor Wiring diagram E6021 COMPRESSOR ACTIVATION .

The outdoor temperature sensor is located on door mirror P60: the sensor is connected to the control unit on door H44 and thence, via the CAN network, to M70.

Pins 34 and 35 of control unit M70 connect to Body Computer M1 and node H44 via the CAN line and exchange the following signals:

• speedometer signal
• windscreen washer activation signal for recirculation activation
• window and sun-roof closure control
• battery voltage signal
• rear window activation signal

Wiring diagram

Components

Component location