AIR CONDITIONING - Description

Description

The vehicle climate control system involves a duct/distributor unit with a heater. The air conditioning system includes the heater and has the function of producing cold, dehumidified air by switching on the compressor and the cooling system.

The climate control is operated by acting on the three knobs in the dashboard:

• the left knob controls mixing of hot and cold air;
• the right knob, mechanically operated via a cable, controls the opening of the flaps which regulate the distribution of air flows;
• the centre knob electrically controls the ventilation of the air at four different speeds;

The air recirculation button and the button for switching on the air conditioning compressor are located in the lower part of the control panel.

A dedicated control unit manages system operation by controlling:

• 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.

According to the setting, the control unit adjusts passenger compartment air intake speed by means of the fan motor and air temperature by a mixer actuator. It also controls flow distribution via another actuator and - lastly - the interior/exterior air recirculation function via a final actuator.

When required, the ECU automatically activates the cooling circuit and dehumidifies the air by operating the air conditioner compressor See E6021 COMPRESSOR ENGAGEMENT.

For more details Characteristic of working principle 5040 AIR CONDITIONING CASING AND COMPONENTS.

Recirculation brings about closing of windows See E3050 ELECTRIC FRONT WINDOWS and sun roof See 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 See E3050 ELECTRIC FRONT WINDOWS and sun roof See 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.

Automatic climate control

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.
• fan speed (varies continuously);
• activation of the compressor (air cooling 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 controls flow distribution via another actuator and - lastly - the interior/exterior air recirculation function via a final actuator.

When required, the ECU automatically activates the cooling circuit and dehumidifies the air by operating the air conditioner compressor See E6021 COMPRESSOR ENGAGEMENT.

1.9 JTD 8V, 1.9 JTD 16V · Automatic climate control

Description

On Diesel versions there is an additional electric heater which is switched on if the temperature of the coolant reaching the heater is low. See E6015 ADDITIONAL HEATER

Automatic climate control

Description

For more details Characteristic of working principle 5040 AIR CONDITIONING CASING AND COMPONENTS.

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.

3.2 V6 · GTA

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.
• fan speed (varies continuously);
• activation of the compressor (air cooling 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 controls flow distribution via another actuator and - lastly - the interior/exterior air recirculation function via a final actuator.

When required, the ECU automatically activates the cooling circuit and dehumidifies the air by operating the air conditioner compressor See E6021 COMPRESSOR ENGAGEMENT.

For more details Characteristic of working principle 5040 AIR CONDITIONING CASING AND COMPONENTS.

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 MAXIFUSE.