METHOD FOR CONTROLLING A HEATING, VENTILATION AND AIR CONDITIONING SYSTEM OF A VEHICLE

Abstract

In a method for controlling a heating, ventilation and air conditioning system of a vehicle, a total air flow is generated by means of a fan. The total air flow is divided into partial air flows which are conducted via outlet openings into several selected zones of a vehicle cab of the vehicle. Furthermore, a predefined proportion of the total air flow is set as a partial air flow, wherein the predefined proportion is established using a manually operated, central control device of the heating, ventilation and air conditioning system. A corresponding heating, ventilation and air conditioning system for a vehicle is also described.

Claims

1. A method for controlling a heating, ventilation and air conditioning system of a vehicle, wherein a total air flow is generated by means of a fan and the total air flow is divided into partial air flows which are conducted via outlet openings into several selected zones of a vehicle cab of the vehicle, wherein a predefined proportion of the total air flow is set as a partial air flow for one of said several selected zones, wherein the predefined proportion is established using a manually operated, central control device of the heating, ventilation and air conditioning system.

2. The method as claimed in claim 1, wherein predefined proportions for said partial air flows for different zones of the vehicle cab are depicted on a display.

3. The method as claimed in claim 1, wherein to establish proportions, several values between a minimum value and a maximum value are predefined for selection.

4. The method as claimed in claim 3, wherein when a first proportion for one partial air flow is increased, a second proportion for another partial air flow is reduced.

5. The method as claimed in claim 4, wherein amongst the partial air flows, the partial air flow with largest proportion of the total air flow is selected for reduction.

6. The method as claimed in claim 5, wherein on selection of the partial air flow for reduction, an environmental parameter or a vehicle state is taken into account.

7. The method as claimed in claim 6, wherein if an exterior temperature is below a limit value, a proportion of the partial air flow for deicing of a front windscreen is not reduced below a minimum proportion.

8. A heating, ventilation and air conditioning system for a vehicle, comprising a fan for generating a total air flow, a distribution device for dividing the total air flow into partial air flows for several selected zones of a vehicle cab, and outlet openings for conducting the partial air flows to the selected zones, wherein the distribution device is configured for setting a predefined proportion of the total air flow as a partial air flow, and a manually adjustable central control device to establish the predefined proportion.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0024] The method and system are now described below in more detail as an example with reference to the drawings. The drawings show:

[0025] FIG. 1 a diagrammatic extract of an exemplary embodiment of an HVAC system with a control device and a display,

[0026] FIG. 1a a schematic block diagram of the heating, ventilation and air conditioning system,

[0027] FIG. 2 a simplified flow diagram of an exemplary embodiment of a method according to the invention, and

[0028] FIG. 3a-h a diagrammatic depiction of an extract of a display of the exemplary embodiment according to FIG. 1 in various operating states.

DETAILED DESCRIPTION

[0029] FIG. 1 shows diagrammatically an extract of an HVAC system 10. This shows a control device 12 and a display 14 which are formed by means of a touchscreen 16. The touchscreen 16 is arranged in a dashboard 18 of the motor vehicle, easily within the reach of a driver. In alternative embodiments, the display may comprise a screen, a head-up display, liquid crystal elements, fluorescence elements, light-emitting diodes or similar. The control device 12 then comprises for example rotary knobs, buttons or keys for entering values and changing operating states of the HVAC system 10.

[0030] The HVAC system 10 furthermore comprises components shown in FIG. 1a, such as a fan 82 for generating a total air flow for a vehicle cab or passenger cell, a heater and a cooling system 84 for tempering the total air flow to a predefined temperature, and a distribution device 86 with air pipes, air ducts and branches for conducting partial air flows of the total air flow via outlet openings or vents 88.sub.1-88.sub.3 into a footwell zone, an upper body zone and a front windscreen zone. As well as these three zones, further horizontal zones may be provided such as a head zone, or vertically separated zones such as for example a driver's zone, a passenger's zone or a rear zone (all not shown). In particular, the distribution device 86 comprises choke elements, for example flaps, whichdepending on control settingcan assume not only a first closed end position and a second fully open end position, but also several further intermediate positions, each with different passage opening for partial air flows. With the choke elements, the air volume per time unit and hence the proportion of the total air flow for each of the partial air flows can be adjusted. A specific proportion of the total air flow is conducted into each of the three zones depending on the setting of the choke elements. Furthermore, an electronic control device is provided for controlling the choke elements and the other components of the HVAC system 10.

[0031] The display 14 comprises a display field for the current time 20, an exterior temperature 22, a set interior temperature 24, and a code for a fan power 26. The display 14 also contains a display field for each of the predefined proportions of the partial air flow. Note the front windscreen zone display field 28, the upper body zone display field 30 and the footwell zone display field 32. As shown in FIG. 1, the proportion of the total air flow for the partial air flow for the front windscreen zone is currently 100%, while the proportions of the total air flow for the partial air flows for the upper body zone and the footwell zone each amount to 0% and hence are switched off. The display furthermore contains other display fields (not shown), for example for values and settings of a seat heater, a parking heater and similar. Depending on the operating state of the HVAC system 10 or actuation of the control device 12 by a user, a position, arrangement or form of display fields can also be changed by the control device.

[0032] The control device 12 contains control elements for switching the HVAC system 10 on or off (note control element 34), for activating or deactivating (note control element 36) an automatic regulation of the HVAC system 10, for increasing the predefined interior temperature (note control element 38), for reducing the predefined interior temperature (note control element 40), for increasing the fan power (note control element 42) and hence the total air flow, and for reducing the fan power (note control element 44). Furthermore, the control device contains a respective control element for increasing the proportion of the total air flow for the partial air flow for the front windscreen zone (note control element 46), for the upper body zone (note control element 48) and for the footwell zone (note control element 50). Amongst these control elements, in the state of the HVAC system 10 shown in FIG. 1, only those for the partial air flow for the upper body zone 48 and footwell zone 50 are activated, since the proportion of the total air flow for the partial air flow for the front windscreen zone is already 100% and therefore no further increase is possible. This activation is depicted by arrow symbols for the user.

[0033] Every time one of the activated control elements for partial flows 48, 50 is touched, the corresponding proportion is increased by 10%. In alternative embodiments, other step widths may be provided, such as for example 25% or 5% per activation, or alternatively or additionally an actuatable reduction of proportions. The control device 12 sets the choke elements according to the proportions predefined by the user. In parallel with the increase in a proportion, another proportion is reduced by the control device following established rules. For example, the rules establish a minimum value for one or more proportions so that these proportions cannot be reduced below the minimum value. Environmental parameters, in particular an external temperature or operating values of the vehicle or HVAC system 10, may also be taken into account. In this way, as well as a fan power, the respective proportions of the total air flow for the partial air flows for the front windscreen zone, upper body zone and footwell zone can be adjusted easily using the HVAC system 10.

[0034] FIG. 2 shows a simplified flow diagram of an exemplary embodiment of the method 60. The function and interaction of the components of the HVAC system 10 according to FIG. 1 are described below together with the method according to FIG. 2. Firstly, the control device 12 sets the established starting values for the fan power, i.e. the total air flow, and for the proportion of the total air flow for the partial air flows to the front windscreen zone, footwell zone and upper body zone. When the automatic system is activated, these values are permanently regulated by the control device 12 taking into account measured sensor values and established setpoints.

[0035] If a user wishes to increase the proportion Ai, he activates the corresponding control element 46, 48, 50. The control device detects the desired increase, step 62. Then the largest proportion A2 amongst the other proportions is determined 64. If a check 66 of the largest proportion A2 determined shows that this proportion is not the partial air flow proportion for the front windscreen zone, the determined proportion A2 is selected for reduction 68. If the determined proportion A2 is the partial air flow proportion for the front windscreen zone, it is checked 70 whether an exterior temperature T is below 4 C. and the proportion A2 is less than 30% of the total air flow. If this is not the case, the proportion A2 is selected for reduction 68. Otherwise, the second largest proportion A3 amongst the proportions not provided for increase is selected 72 for reduction. Finally, the selected proportion is reduced by 10% and the 10% increase in proportion Ai desired by the user is made by the control device. For this, the control device 12 adjusts the choke elements of the distribution device accordingly. This prevents the partial air flow proportion for the front windscreen zone from being reduced below 20% if the exterior temperature is less than 4 C. Adequate deicing of the front windscreen is always guaranteed.

[0036] For further description of the method 60 according to FIG. 2 and the HVAC system 10 according to FIG. 1, FIGS. 3a to 3h each show a diagrammatic depiction of an extract 80 of the display 14 in various operating states. Starting from the setting of the partial air flow proportions according to FIG. 1 at 100% for the front windscreen zone and 0% for the upper body zone and footwell zone, the user activates the control element 48 to increase the partial air flow proportion for the upper body zone. Since the proportion for the front windscreen zone is greater than 20% and greater than the proportion for the footwell zone, the control device reduces the proportion to the windscreen zone by 10% and increases the proportion to the upper body zone by 10%. FIG. 3a shows this state. The display fields 28, 30, 32 each show the set proportion for the user.

[0037] According to FIG. 3b, by activating the control element 50, the user has increased the partial air flow proportion to the footwell by 10%. According to FIG. 3c, by repeated actuation of the control elements for the upper body zone 48 and footwell zone 50, the corresponding partial air flow proportions are each increased to 30% of the total air flow. Following the rule described above, the proportion for the front windscreen zone is reduced accordingly.

[0038] In FIG. 3d, the proportion for the upper body zone has been increased by a further 10% to 40% of the total air flow. The proportion for the front windscreen zone has been reduced accordingly to 30% and is now precisely as large as the proportion for the footwell zone. When the proportion for the upper body zone is increased again according to FIGS. 3e to 50% by activation of the control element 48, the control device selects from the two other proportions of the same size, following a predefined order, the front windscreen zone for reduction. The exterior temperature, other environmental parameters or operating states of the HVAC system or vehicle may be taken into account. Alternatively, a random selection is possible between two other proportions of the same size.

[0039] According to FIG. 3f, a further increase in the partial air flow proportion for the upper body zone has been made to 60%. Since in this case the exterior temperature lies below 4 C. and the partial air flow proportion for the windscreen zone is only 20%, on a further increase in the proportion for the upper body zone, only the partial air flow proportion for the footwell zone is reduced. According to FIG. 3g, when the exterior temperature is below 4 C., finally a maximum increase in the proportion for the upper body zone to 80% is reached, while the proportion for the front windscreen zone is 20% and the proportion for the footwell zone is 0%. FIG. 3h depicts an operating state at an exterior temperature above 4 C. The proportion of the partial air flow for the upper body zone has been increased to 100% by repeated actuation of the control element 48, while the two other proportions have been reduced to 0% and hence switched off.

[0040] Obvious modifications and variations are possible in light of the above teachings. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.