Heating & Ventilation: Overview Jaguar S-type I

Description and Operation

The heating and defrosting system

1. controls the vehicle air temperature and, during A/C operation, reduces the relative humidity of the air inside the vehicle.
2. delivers heated or cooled air to maintain the vehicle interior temperature and comfort level.
3. controls the A/C blower motor speed.
4. allows temperature to be adjusted individually by the driver and the passenger to maintain comfort.
5. uses a reheat method to provide conditioned air to the passenger compartment. All airflow from the blower motor passes through the A/C evaporator core. Temperature is regulated by reheating a portion of the air and blending it with the remaining cool air to achieve the desired temperature.
6. blends the air temperature by regulating the flow of engine coolant to separate halves of the heater core. A dual solenoid actuated valve is used to control the flow of coolant.

The blower motor draws outside air through the air inlet filter and duct during all system operations except for MAX A/C cooling (when recirculated air is used).

Scheme 18

Scheme 19

The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer it to air passing through the heater core. The heater core is separated into two sections. Air passing through one section is directed to the driver side of the vehicle, while air passing through the other section is directed to the passenger side of the vehicle. The heater core has separate inlet ports with a common outlet port.

Scheme 20

The A/C blower motor pulls air from the air inlet and forces it into the evaporator housing and plenum assembly which is attached to the instrument panel where it is mixed and distributed.

Scheme 21

The dual coolant valve regulates the flow of engine coolant to each half of the heater core. Two electric solenoids, Which are individually actuated by the heater control module, are the control elements. The valve contains five ports

1. inlet port-coolant from the engine
2. outlet port - coolant to driver side of heater core
3. outlet port - coolant to passenger side of heater core
4. return port - common coolant return from heater core
5. outlet port - coolant return to engine

Scheme 22

The auxiliary water pump is electrically driven and provides increased coolant flow during low engine speed operation. The pump is also used to circulate coolant after the engine is turned off under certain conditions.