GB2093983A

GB2093983A - Control unit for a heating and ventilating or air conditioning system of a motor vehicle

Info

Publication number: GB2093983A
Application number: GB8205784A
Authority: GB
Original assignee: Ford Motor Co Ltd; Ford Motor Co
Current assignee: Ford Motor Co Ltd; Ford Motor Co
Priority date: 1981-02-28
Filing date: 1982-02-26
Publication date: 1982-09-08
Also published as: FR2500794A1; JPS57198114A; DE3107722A1

Abstract

A control unit for a vehicle heating and ventilating or air conditioning system includes a temperature selector switch 2 for automatic control of a flap 4 and a programme selector 6. The latter is a push button unit having several buttons 11 each operative to set a predetermined combination of the positions of flaps 12, 13 and the speed of a blower 9. This simplifies control in that the driver need only select the desired temperature and press a button which is readily identifiable with the prevailing weather conditions. <IMAGE>

Description

SPECIFICATION Control unit for a heating and ventilating system of a motor vehicle The invention relates to a control unit for a heating and ventilating system of a motor vehicle having a plurality of control elements, and connected to a plurality of power or servo assisted regulating or setting devices.

Control units of this type are already known from German Auslegeschrift 2,654,357 and German Auslegeschrift 2,654,552. The control elements for the various regulating circuits are, in these cases, designed as multi-stage rotary switches and the various circuits are linked to one another differently in different positions of the control elements in order to bring about predetermined positions of air flaps adjustable via power assisted setting devices, or predetermined settings of a multi-speed blower or fan.

These known control units have the disadvantage that they are difficult to master for the driver of a motor vehicle. The driver has to find out either from the operating manual or from experience, the positions of the control elements which are recommended for particular climatic conditions or which turn out to be favourable.

When the particular climatic conditions arise, the driver has to make appropriate selection of the functional positions on the various control elements.

Observations and investigations as to the extent to which a driver of a motor vehicle is conversant with the proper operation of a plurality of control elements of a control unit for a heating and ventilating system of a motor vehicle, have revealed that the majority of drivers only arrive at an acceptable setting of the heating and ventilating system after a considerable time and only after having tried a plurality of different positions.

The present invention seeks to provide a control unit in which the operator is relieved of burden of having to select the position of a plurality of control elements in order to select settings appropriate to any particular set of climatic conditions.

According to the present invention, there is provided a control unit for a heating and ventilating system ofa motor vehicle as herein set forth in Claim 1.

Preferred features of the invention are set forth in Claims 2 to 11.

The driver of a motor vehicle now has only to select the desired passenger compartment temperature and to press one of a plurality of push buttons appropriate to the prevailing climatic conditions. The temperature selector, as known per se, automatically controls the proportion of air flowing past a heat exchanger prior to entering the passenger compartment so as to regulate the interior temperature. This control, as known per se, can be effected in a circuit in which feed back is derived from a temperature sensor within the passenger compartment to regulate the position of a temperature adjuster flap.

The push buttons may conveniently be labelled in accordance with the climatic conditions to which they relate. For example the push buttons may be labelled with wording or symbols to indicate if the weather is very hot, temperate or very cold. In addition, it is preferred to provide a button to switch off the whole system to isolate the interior of the car from the ambient atmosphere, for the example in the event of external pollution. It is also desirable to provide a programme specifically for demisting or defrosting the windscreen.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows, next to one another, the block set of diagrams for the temperature selection control and the programme selection control of a control unit of the invention, Figure 2 shows a schematic vertical section through a motor vehicle to illustrate the heating and air conditioning system for a motor vehicle and the control unit, Figure 3 shows a view of the control unit provided within the passenger compartment, Figure 4 shows a table of the climatic conditions to which the different programmes relate, and Figures 5 to 9 show schematic sections through the heating and air conditioning system illustrating the positions adopted by the system when different programme push buttons have been selected.

Figure 1 shows a control unit for a heating and air conditioning system of a motor vehicle which consists of a temperature selection control circuit 1 and of a programme selection circuit 5. The temperature selection control circuit 1 comprises a temperature selector switch 2, an interior temperature sensor 3 and a temperature flap adjuster 4. The programme selection circuit 5 comprises a programme selection part 6, and air distributor flap adjuster 7, a circulating air flap adjuster 8, the circuit of the blower 9 and the circuit of the compressor 10.

As is evident from Figure 2, the heating and air conditioning system of a motor vehicle consists ot' a conventional arrangement of an evaporator, a blower of a heat exchanger and a distributor housing with various air flaps. To decribe the present control unit, it is merely necessary to refer to a few of the components of the heating and air conditioning system, so that only these have been given reference numerals.

The control unit of the invention, with its temperature selector switch 2 and its programme selection part 6, is located on the dashboard of the motor vehicle. As is evident from Figure 3, the control unit has five push buttons 11 which are designated by appropriate symbols and which are assigned to various characteristic climatic conditions.

Since the temperature selection control circuit 1 can be assumed to be known, only the essential elements of the programme switching circuit 5 will be described in detail. This circuit includes an air distributor flap 12 which controls the distribution of the air quantity between the footwell and the demister nozzles. There is also included a circulating air flap 13, a blower 9 and a compressor 10.

The climatic conditions assigned to the different programme buttons can clearly be seen, without detailed explanation, from the table in Figure 4.

The function of the heating and air conditioning system of a motor vehicle, which is operated by a control unit of the invention, will now be described in more detail with reference to Figures 5to9.

When the push button 11, labelled "off" is actuated, the circulating air flap 13 is brought into the position for causing air circulation, in which position it prevents fresh air from entering the passenger compartment. The "off" button also shuts off the blower and the compressor so that essentially the whole system is shut down. It is believed that the manner in which the actuation of the push button controls the various elements will be clear to a person skilled in the art without detailed description. As an example, the push buttons may be electrical push buttons associated with electrical relays directly operating servo motors which set the various flaps to the desired positions and which appropriately switch on the compressor and the blower to the correct speed.

Alternatively, hybrid systems may be employed wherein solenoid operated valves may control vacuum operated servo motors to set the positions of the individual flaps.

When the push button with the labelled "hot conditioning" is actuated, the circulating air flap 13 is brought into its position for circulating the air while the air distributor flap 12 is set to a position in which it directs 90% of the air flow to the upper, side and middle nozzles and only 10% of the air flow to the footwells, the blower 9 being switched to maximum power and the compressor 10 switched on.

When the push button labelled "normal conditioning" is actuated, the circulating air flap is set into its position for letting in fresh air and the air distributor flap 12 is set to a position in which it distributes the air flow to all outlets, that is to say to the demister nozzles, the side and middle nozzles and the footwell outlets. The blower in this case is set to 50% of maximum speed and the compressor 10 is switched on.

When the push button labelled "cold conditioning" is depressed, the air flaps adopt the same positions for normal conditioning but the blower speed is increased to 75% of maximum speed and if provided the compressor 10 of the air conditioning system is switched off.

Finally, when the push button labelled "defrosting" is actuated, the air distributor flap 12 is set to direct the entire air flow to the demister nozzles and to the side and middle noules while the footwell outlets are closed. In this case, the blower is operated at maximum speed and if air conditioning is provided the compressor is switched on in order to dehumidify the fresh air in the event that it is excessively moist.

It is evident from the foregoing description that the driver of a vehicle need only actuate a push button which is readily recognisable as relating to the prevailing climatic conditions, in order to select the optimum combination of blower speed and flap positions to provide maximum passenger comfort. The invention therefore, considerabiy simplifies the task of controlling the heating system.

Claims

1. A control unit for a heating and ventilating system of a motor vehicle having a plurality of control elements connected to a plurality of power or servo assisted setting devices, the control unit comprising a temperature selector control for setting the desired temperature in a control circuit which further comprises a temperature sensor and a temperature flap adjuster, and a programme selector control for setting the speed of a multi-speed blower, and the positions of power or servo assisted setting devices associated with an air distributor flap and a circulating air flap, wherein the programme selector control comprises a plurality of push buttons each operative to set a predetermined combination of blower speed, air distributor flap position and circulating air flap position appropriate to predetermined climatic conditions.

2. A control unit according to Claim 1 in which the programme selector control includes a first push button operative to switch off the blower and to set the circulating air flap for recirculation.

3. A control unit as claimed in Claim 2 for a vehicle fitted with air conditioning, in which the said first push button is operative to switch off the compressor.

4. A control unit according to anypreceding claim, in which the programme selector control includes a push button, hereinafter termed the second push button, operative to locate the circulating air flap in the circulating air position and to set the air distributor flap to direct 90% of the air flow to the side and middle nozzles and 10% of the air flow to the footwell outlets and to set the blower to maximum speed.

5. A control unit as claimed in Claim 4 for use in a motor vehicle fitted with air conditioning in which the said second push button is operative to switch on the compressor.

6. A control unit as claimed in any preceding claim wherein the programme selector control comprises a push button, hereinafter termed the third push button, operative to set the circulating air flap to direct fresh air into the passenger compartment, to set the air distributor flap to direct the air flow substantially equally to all outlets and to set the blower to half speed.

7. A control unit as claimed in Claim 3, for use in a motor vehicle fitted with air conditioning, wherein the said third push button is operative to switch on the compressor.

8. A control unit as claimed in any preceding claim in which the programme selector control includes a push button, hereinafter termed the fourth push button, operative to set the circulating air flap to direct fresh air into the vehicle passenger compartment, to set the air distributor flap to distribute the air flow substantially equally to all outlets and to set the blower to threequarters of maximum speed.

9. A control unit as claimed in Claim 8 for use in a motor vehicle fitted with air conditioning, in which the said fourth push button is operative to switch off the compressor.

10. A control unit as claimed in any preceding claim in which the programme selector control includes a push button, hereinafter termed the fifth push button, operative to set the position of the air distributor flap to shut off the air flow to the footwell and to set the blower to maximum speed.

11. A control unit as claimed in Claim 10 for use in a motor vehicle fitted with air conditioning, in which the said fifth push button is operative to switch on the compressor.

12. A control unit for a motor vehicle, constructed, arranged and adapted to operate substantially as-herein before described with reference to and as illustrated in the accompanying drawings.