AIR DISTRIBUTION SYSTEM Volvo XC90 I

AIR DISTRIBUTION SYSTEM

See: AIR DISTRIBUTION SYSTEM

Scheme 300

The fan wheel is the radial type with a guide vane rim on the outer edge. The fan wheel is balanced using steel clips.

The blower fan motor is a permanent magnet type fan.

The blower fan has stepless electronic control.

The power unit is mounted under the fan unit. The power unit can be removed.

Scheme 301

The filter is located after the fan to also clean recirculated air. The filter is coded, that is, designed so that it cannot be installed incorrectly.

There are two types of filter.

1. Particle filter
2. Multi-filter.

The multi-filter filters particles in the same way as the particle filter. The multi-filter contains active carbon which reduces the influx of gases (bad odors) into the passenger compartment.

The multi-filter is only available for vehicles with electronic climate control (ECC) and then in combination with the air quality sensor (AQS).

Note. The climate control system has either a particle filter or a multi-filter, never both.

Scheme 302

In order to heat the air in the passenger compartment, the heating system uses the heat that is generated by the engine. The heat exchanger is connected to the cooling system for the engine. The outlet connection for the heat exchanger is located directly on the engine at the point where the pressure and temperature of the coolant are highest. The coolant flows through the cooling ducts for the engine block and on into the heat exchanger. The return flow is connected to the return pipe on the suction side of the water pump.

The heat exchanger comprises a pipe loop through which the engine coolant flows. The pipe has flanges that provide heat to the airflow.

Engine coolant constantly flows through the heat exchanger. There is no valve to regulate the flow. The selected temperature is achieved using dampers for the right and left-hand sides of the car installed upstream of the heater element. These control the amount of air to be warmed. There is also a damper after the heater element which guides air out into the passenger compartment through the various vents.

Scheme 303

Vehicles with engine B8444S have an electric pump in the coolant circuit to ensure a comfortable level of heating is supplied to the passenger compartment. The electric pump increases the amount of coolant the flows through the heat exchanger. The pump is located in the engine compartment within the front fender in front of the front left wheel housing.

Scheme 304

1. Control module
2. Water pump
3. Fan shroud
4. Fuel pump (FP) (in front of the fuel tank)
5. Heat exchanger

Gasoline driven vehicles can use a parking heater with timer function.

The additional heater/parking heater are positioned inside the front fenders, in front of the front left wheel arch.

The heater consists of

1. the heater unit
2. the combustion preheater module (CPM)
3. the exhaust system
4. the air intake
5. the water pump.

The heater is connected to

1. the engine cooling system
2. the vehicle fuel tank
3. central electronic module (CEM).

Both versions have a fuel pump (FP) located on the right-hand side in front of the fuel tank.

Vehicles with the parking heater function use the turn signal lamp stalk to control the heater. The information appears in the driver information module (DIM).

Scheme 305

1. Heat exchanger
2. Damper motor, temperature, left
3. Blower fan
4. Damper motor, fresh air intake and recirculation damper
5. Power unit for blower fan motor
6. Particle filter or multi-filter
7. Damper motor, ventilation and floor (also defroster for MCC)
8. Damper motor, temperature, right
9. Damper motor, defroster (only ECC)
10. Air quality sensor (AQS)
11. Evaporator temperature sensor.

Scheme 306

There are five main components in the climate control system

1. evaporator
2. receiver drier
3. compressor
4. condenser
5. expansion valve.

The system is filled with a suitable quantity of refrigerant and oil. The role of the oil is to lubricate and seal the compressor (piston and cylinder).

A fluorescent leak-tracing agent is added to the refrigerant. The leak-tracing agent makes it possible to trace leaks using UV light.

Scheme 307

Included in the climate control system

1. Compressor
2. Condenser
3. Engine cooling fan (the same cooling fan used by the engine cooling system)
4. Receiver drier
5. Expansion valve
6. Evaporator
7. Blower fan.

Explanation

A - High pressure, warm fluid

B - Low pressure, cold fluid

C - Low pressure, cold gas

D - High pressure, warm gas

Dark arrow - Warm air

Light arrow - Cold air

The system is divided into

1. a low pressure side (B, C)
2. a high pressure side (A, D).

The two sides are separated by the compressor (1) and the expansion valve (5). The evaporator (6) is located on the low pressure side and the condenser (2) is on the high pressure side.

The design of the climate control system in a vehicle is based on the laws of nature, which mean that liquids evaporate when they are subjected to a temperature increase or a reduction in pressure and that heat is absorbed during this process.

If the hot vapor is then cooled again, the heat that has been absorbed is released and the gas reverts to liquid form. This process is repeated as many times as necessary, so that "cooling is produced" continually. This is the same type of process as used in refrigerators, for example.