Controlling The Climate In The Passenger Compartment

Fig 1: View Of Passenger Compartment Climate Control Components

Courtesy of VOLVO CARS CORPORATION

The way in which the climate in the passenger compartment is regulated depends on the type of climate control module (CCM) in the car.

ECC

Electronic climate control means that either manual settings or the AUTO function can be used. In the latter case the control module automatically regulates heat, air conditioning, recirculation and air distribution until the selected temperature is achieved.

Manual climate control (MCC)

Manual climate control means that heat, air conditioning, recirculation and air distribution must be selected manually.

Climate control module (CCM) (3/112) regulates the following:

Activation of the air conditioning (A/C) compressor (8/3) using a request via the controller area network (CAN) to the engine control module (ECM) (4/46)
Controlling the damper motors. For ECC (6/48), (6/95), (6/96), (6/102) and (6/103). For MCC (6/48), (6/95), (6/102) and (6/103)
The speed of the blower fan (6/28) using a request to the central electronic module (CEM) (4/56) via the controller area network (CAN).

The climate control module (CCM) regulates the climate in the passenger compartment based on the following input signals:

Passenger compartment temperature, signal from the passenger compartment temperature sensor (6/117)
Outside temperature, signal from the outside temperature sensor (7/69) via the central electronic module (CEM) on the controller area network (CAN)
Evaporator temperature (only ECC), signal from evaporator temperature sensor (7/41).
Status of the side window, signals from the driver door module (DDM) (3/126) and passenger door module (PCM) (3/127) via the controller area network (CAN)
Status of the doors, signal from the central electronic module (CEM) via the controller area network (CAN)
The sun intensity, signal from sun sensor (7/12) via the central electronic module (CEM). After structure week 200746, there are 2 signals, one for the right-hand side and one for the left-hand side.
Speed, signal from the brake control module (BCM) (4/16) via the controller area network (CAN)
Status of the windshield wipers, signal from the steering wheel module (SWM) (3/254) via the controller area network (CAN).

The climate control module (CCM) (for ECC) uses information about the status of the side windows and doors to determine how it should compensate for changes in the passenger compartment temperature. If any side windows or doors are opened, the climate control module (CCM) will not compensate for a change in the passenger compartment temperature. Instead it maintains the same level of climate control for the compressor and blower fan as before.

The climate control module (CCM) (for ECC) uses the signal from the steering wheel module (SWM) indicating that the windshield wipers are on. This is to regulate the blower fan and the damper motor to remove any mist from the inside of the windshield when it rains.

For vehicles manufactured before structure week 200745, the following applies:

The climate control module (CCM) (for ECC) uses the signal from the sun sensor to compensate for high sun intensity. This is done by lowering the temperature of the ventilation air, altering air distribution and increasing the speed of the blower fan.

For vehicles manufactured after structure week 200746, the following applies:

The Climate control module (CCM) (for ECC) registers the sun intensity on the left and right sides. Using these signals, the Climate control module (CCM) compensates for the high sun intensity.

This is done by reducing the temperature of the ventilation air on the affected side. The distribution of air is altered and the speed of the passenger compartment fan is increased.

The climate control module (CCM) (for ECC) uses the signal from the evaporator temperature sensor to control the activation of the air conditioning (A/C) compressor. If the signal from the evaporator temperature sensor indicates an evaporator temperature below 6 °C, the compressor is not permitted to start because of the risk of freezing.

To maintain a constant flow of air in the passenger compartment, the climate control module (CCM) (for ECC) uses the speed signal from the brake control module (BCM) to regulate the speed of the blower fan. Generally, as the speed of the car increases the speed of the blower fan decreases.

At higher speeds the flow of air into the fresh air damper is adjusted.

When adjusting the climate settings manually, such as setting the temperature, this is displayed on the infotainment control module (ICM). The climate control module (CCM) transmits a signal to the infotainment control module (ICM) (16/1) via the controller area network (CAN).

Electrical additional heater

Climate control module (CCM) (3/112) checks the function of the electrical additional heater.

The central electronic module (CEM) transmits information regularly to the climate control module (CCM), for example, about the permitted size of the output voltage.