GB2562249A

GB2562249A - Vehicle climate system

Info

Publication number: GB2562249A
Application number: GB1707412.1A
Authority: GB
Inventors: Keith Baker Roger; Simoes Mauro
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2017-05-09
Filing date: 2017-05-09
Publication date: 2018-11-14
Also published as: GB201707412D0

Abstract

A method and system are described for controlling a vehicle climate system in a vehicle having at least two zones, which may be driver and passenger zones. A controller is configured to determine first and second target air flow temperatures for first and second zones respectively, and determine whether the second zone is occupied. If the second zone is unoccupied, the controller calculates at least one characteristic of air flow, such as air flow rate or air flow distribution over screen, foot and face regions. The first target temperature value and a measured temperature value, but not the second target temperature value, are included in the calculation. The controller then instructs a heating, ventilation and air conditioning (HVAC) unit to provide an air flow with the calculated characteristic to both zones. Occupancy may be detected with a seatbelt, pressure, infrared or door sensor, or with a camera.

Description

VEHICLE CLIMATE SYSTEM

TECHNICAL FIELD

The present disclosure relates to a vehicle climate system. Particularly, but not exclusively, the disclosure relates to vehicle climate systems that provide zoned temperature control. Aspects of the invention relate to a method for controlling a vehicle climate system, to a vehicle climate system, and to a vehicle.

BACKGROUND

Existing vehicle climate systems typically provide air flow that is distributed between different regions inside the vehicle. For example the air flow can be provided to a face region, a foot region and/or a screen region, typically by directing air flow from a heating ventilation and air conditioning (HVAC) unit between different outlets. The distribution of air flow can be based on a setting selected by a person in the vehicle (for example 100% of air flow to a screen region, or 80% of air flow to a foot region and 20% of air flow to a face region).

Typically the distribution of air flow between regions in the vehicle is also based on a user-selected temperature setting. It is known that vehicle occupant concentration and comfort improves when the air flow provided to a face region is of a lower temperature than air flow provided to a foot region. For example vehicle occupants are typically comfortable with face region vent temperatures between 24-27 degrees Celsius and foot region vent temperatures between 34-38 degrees Celsius. Accordingly, it is known for vehicle climate systems to alter the distribution of air flow for a given user-selected temperature setting such that the air flow to the face region is reduced as compared to the foot region. This is illustrated by the graph shown in figure 1. The example of figure 1 shows that for air temperatures over about 16 degrees Celsius, the distribution is automatically changed such that some portion of the air flow has to be directed towards the foot region in addition to the face region. As the temperature increases, more air flow is directed towards the foot region relative to the face region. By around 38 degrees Celsius, substantially all the air flow is distributed towards the foot region.

Typically HVAC units in known vehicle climate systems provide an air flow, which is then distributed between the different regions. The air flow rate (i.e. the volume of air delivered by the HVAC unit per unit time) can be changed by altering the speed of fans within the HVAC unit. The air flow is also a function of temperature, and in particular is typically based on the difference between the actual temperature of the vehicle interior and the user-selected temperature setting.

Some vehicle climate systems also facilitate zoned temperature control, by providing air flow having a different temperature to different zones in the vehicle. For example a vehicle may have a left zone and a right zone (for example corresponding to a zone occupied by a driver and a zone occupied by a passenger), or a front zone and a rear zone (for example corresponding to front and rear seats), or combinations thereof. Persons in each zone can provide a temperature setting for their zone via a suitable input, and in response the HVAC unit can be configured to provide air flow to each zone having a temperature corresponding to the respective temperature setting for that zone.

Whilst the temperature can be set to different values for different zones in such systems, the distribution (i.e. the proportion of air flow being delivered to the face, foot and screen regions respectively) is typically not variable for different zones. Because the distribution is typically based at least in part on temperature settings as noted above, in systems having zoned temperature control, the distribution is typically a compromise based on the temperature setting for each zone.

Similarly, the air flow rate is typically not variable for different zones (HVAC units typically comprise a single fan for altering the air flow rate to all zones of the vehicle). Accordingly the air flow is also a compromise based on the temperature settings for each zone (for example based on a difference between an actual temperature of the interior of the vehicle and the average of the temperature setting for each zone).

In other words, in vehicle climate systems that allow different temperature settings for different zones, the air flow distribution and the air flow are typically treated as a "single zone". Thus in situations in which the temperature setting for each zone is different, the compromise distribution and compromise air flow is often not ideal for any occupant. In such systems the only way to ensure the distribution is not a compromise it to manually select the same desired temperature for all zones in the vehicle.

It is an aim of the present invention to address disadvantages associated with the prior art.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide a method for controlling a vehicle climate system, a vehicle climate system, and a vehicle as claimed in the appended claims.

According to an aspect of the invention, there is provided a method for controlling a vehicle climate system in a vehicle having at least two zones; the method comprising: determining a first target air flow temperature value for a first zone; determining a second target air flow temperature value for a second zone; determining whether the second zone is occupied by a person; in the event that it is determined that the second zone is unoccupied: calculating at least one characteristic of air flow, wherein the first target air flow temperature value and a measured temperature value are included in the calculation and the second target air flow temperature value is omitted from the calculation; instructing the vehicle climate system to provide an air flow to the first and second zones having the calculated characteristic.

According to another aspect of the invention, there is provided a vehicle climate system for a vehicle having at least two zones, wherein the vehicle climate system comprises: a controller; and a heating, ventilation and air conditioning unit capable of providing air flow; wherein the controller is configured to: determine a first target air flow temperature for the first zone and a second target air flow temperature for a second zone; determine a first target air flow temperature value for a first zone; determine a second target air flow temperature value for a second zone; determine whether the second zone is occupied by a person; in the event that it is determined that the second zone is unoccupied: calculate at least one characteristic of air flow, wherein the first target air flow temperature value and a measured temperature value are included in the calculation and the second target air flow temperature value is omitted from the calculation; instruct the heating, ventilation and air conditioning unit to provide an air flow to the first and second zones having the calculated characteristic.

According to an embodiment, the at least one characteristic of the air flow may be one or more of: an air flow distribution (i.e. a distribution of the air flow over a plurality of regions in the vehicle, for example the relative proportions of air flow being directed to a screen region, a foot region and a face region); and an air flow rate.

Advantageously this embodiment of the invention calculates air flow characteristics differently to known systems in the event that no occupant (e.g. person) is detected in one of the zones. If no occupant for a particular zone is detected (e.g. it is determined that the zone is unoccupied), then the target temperature value for that zone is essentially ignored when calculating what the characteristics of the air flow from the vehicle climate system should be. Accordingly the resulting characteristics such as air flow distribution and air flow rate may be based only on the occupied zone(s) in the vehicle, rather than being a compromise based on the target air flow temperature values of both occupied and unoccupied zones. Consequently this embodiment of the invention allows for improved comfort for occupants in vehicles having zoned temperature control.

According to another embodiment, determining at least one of the first and second target airflow temperature values may be based on a user selected temperature value (e.g. an input indicating a desired temperature). For example the user-selected temperature setting may be input by a user (for example at a suitable input device in the vehicle, which may transmit the user selected temperature value), which is subsequently received by the vehicle climate system (for example by the controller).

It is noted this embodiment of the invention is particularly advantageous in situations in which an unoccupied zone has a target temperature value that is significantly different to the target temperature value of an occupied zone, for example if one of the unoccupied zones is subject to a high sun load (i.e. a high thermal load caused by solar radiation incident on the zone) but the occupied zone is not occupied. According to another embodiment, the controller may be configured to determining at least one of the first and second target airflow temperature values is based on a detected sun load, for example based on the output of a first sensor (e.g. a solar sensor) configured to measure the thermal load provided by the sun in one or more of the first and second zones. For example the controller may be configured to receive a first signal from the first sensor, the first signal indicating a sun load. In such cases this embodiment of the invention advantageously prevents the air flow having a compromise characteristic (e.g. distribution or rate) that is quite different to an optimal characteristic.

According to another embodiment, the determination of the presence of a person in any particular zone may be based on the output of a second sensor, the second sensor configured to provide an indication of whether the second zone is occupied by a person. For example the controller may be configured to receive a signal from the second sensor, the second signal indicating whether the second zone is occupied by a passenger.

According to a further embodiment, the determination of the presence of an occupying person in any particular zone may be based on the output of either a seatbelt sensor associated with the zone or a door sensor associated with the zone. Advantageously such sensors are often employed in vehicles for other purposes, and thus do not have to be retrofitted in order to implement this embodiment of the invention. In one embodiment of the invention the detection may be based on the seatbelt sensors, or both the seatbelt sensors and door sensors. In an embodiment, determining whether the second zone is occupied by a person comprises determining, using received data from a door sensor, whether a door associated with the door sensor has been opened within a predetermined period of time, in one embodiment since one or more of: a time at which the door was unlocked; or a time at which the vehicle's ignition was switched on.

According to a still further embodiment, detection of the presence of a person in any particular zone is based on the output of at least one of an optical sensor (for example a camera of infrared sensor), and a pressure sensor associated with a seat in one of the zones. Advantageously such sensors provide enhanced accuracy in the determination of whether a person is occupying any particular zone.

According to an embodiment the at least two zones comprise a driver zone and a passenger zone.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a graph illustrating an automatic modification of air flow distribution according to vent temperature as known in the art.

Figure 2 is a top-down schematic of a vehicle having a plurality of zones, in which an embodiment of the invention can be implemented.

Figure 3 is a side-view schematic of a portion of the vehicle of figure 2.

Figure 4 is a method for controlling a vehicle climate system in accordance with an embodiment of the invention.

DETAILED DESCRIPTION

Figure 2 shows a schematic of a vehicle 200 having a plurality of zones 202, 204, 206 in which an embodiment of the invention can be implemented. Each zone 202, 204, 206 defines a portion of the interior (also referred to as the cabin) of the vehicle 200 that may be occupied by a person. As shown in Figure 2, the vehicle has three zones 202, 204, 206, including a driver zone 202, and front passenger zone 204 and a rear passenger zone 206.

Alternatively the vehicle 200 can have any zone configuration comprising at least two zones known in the art. An embodiment of the present invention may be applied to any configuration of zones in a vehicle for example, but not limited to: a single front zone and a single rear zone (for example a front zone corresponding to a combination of the driver zone 202 and front passenger zone 204 as shown in figure 2, with a rear zone 206); a single left-hand zone and a single right-hand zone (for example a left-hand zone corresponding to a combination of the driver zone 202 and a left-hand portion of the rear zone 206 as shown in figure 2, and a right-hand zone corresponding to a combination of the front passenger zone 204 and a right-hand portion of the rear zone 206 as shown in figure 2); a front left-hand zone, a front right-hand zone, a rear left-hand zone and a rear right-hand zone (for example zones corresponding to a driver zone 202, front passenger zone 204, left-hand portion of the rear passenger zone 206, and right-hand portion of rear passenger zone 206 as shown in figure 2); etc.

The vehicle 200 comprises a vehicle climate system comprising a heating, ventilation and air conditioning (HVAC) unit 208 configured to provide air to the interior of the vehicle 200, and a controller 209 coupled to the HVAC unit 208. The controller 209 is configured to control the HVAC unit. The vehicle 200 also comprises an interior temperature sensor 210 to measure the temperature of the interior of the vehicle 200. The controller 209 determines the temperature of the air delivered to each zone 202, 204, 206 by the HVAC unit 208, based on the temperature measured by the interior temperature sensor 210 and a target air flow temperature value associated with each zone 202, 204, 206. In an example the target air flow temperature value for each zone is based on a user-selected temperature setting that is transmitted to the controller 209.

The controller 209 is configured to instruct the HVAC unit 208 to provide air flow having a particular air flow rate. The HVAC unit 208 is able to alter the air flow rate by altering the speed of a fan or blower within the HVAC unit 208. Such functionality of the controller 209 occurs in a known manner.

Optionally the vehicle 200 comprises one or more further sensors selected from: an exterior temperature sensor 212 configured to measure the air temperature outside the vehicle 200; a solar sensor 214 configured to measure the thermal load provided by the sun (also referred to as "sun load") in one or more of the zones 202, 204, 206 (for example a photodiode); an HVAC unit sensor 216 configured to measure at least one of the temperature of an evaporator of the HVAC unit 208, a current supplied to a compressor of the HVAC unit 208, a water temperature and a refrigerant temperature. In this case the further sensors are configured to transmit their measurements to the controller 209, which then calculates the target air flow temperature value based on the output of one or more of the further sensors 212, 214, 216 in addition to the user-selected temperature setting. In an embodiment the calculation of the target air flow based on the output of the sensors and user-selected temperature setting occurs in a known manner. In one example the controller 209 can receive a signal from the HVAC unit sensor 216 indicating that the temperature of the evaporator is outside of a predetermined range, and calculate the target air flow temperature value based on the received signal, such that by heating air in accordance with the target airflow temperature value, the temperature of the evaporator may be brought back to within the predetermined range.

In an embodiment, the vehicle 200 further comprises one or more zone occupancy sensors 220, 222, 224, 226, 228, 230, 232, 234, 236, 238 configured to provide an indication of whether a zone 204, 206 is occupied by a person.

In some embodiments the zone occupancy sensors are seatbelt sensors 220, 222, 224 configured to provide an indication that an associated seatbelt is fastened or unfastened, from which it can be inferred that a person is or is not present in the zone respectively. Alternatively the zone occupancy sensors are door sensors 234, 236, 238 configured to provide an indication that a door associated with a zone 204, 206 has been recently opened. Advantageously, vehicles typically comprise pre-existing seatbelt sensors 220, 222, 224 and door sensors 234, 236, 238 for other purposes. Thus by using pre-existing seatbelt sensors 220, 222, 224 or door sensors 234, 236, 238 to detect zone occupancy, no additional sensors need to be installed in vehicles for the purpose of performing the method described below, thereby reducing cost and furthermore allowing the invention to be implemented in existing vehicles.

Alternatively the zone occupancy sensors are either: pressure sensors 226, 228, 230 situated in seats associated in the respective zones 204 (which measure pressure applied by a person on the seat when they sit in the seat), 206; or one or more optical sensors 232 (for example a camera or infra-red sensor) configured to detect the presence of a person in one or more of the zones 204, 206. Advantageously these options provide for more accurate determination of zone occupancy in the event that a person is present in a zone 204, 206 but has not fastened their seatbelt (for example if the vehicle is stationary) or recently opened a door. Optionally the zone occupancy sensors 220, 222, 224, 226, 228, 230, 232, 234, 236, 238 comprise a combination of different types of sensor selected from seatbelt sensors 220, 222, 224, door sensors 234, 236, 238, pressure sensors 226, 228, 230 and optical sensors 232.

The zone occupancy sensors 220, 222, 224, 226, 228, 230, 232, 234, 236, 238 are communicatively coupled to the controller 209, and transmit signals indicating whether a person is present in each zone 204, 206 to the controller 209.

Figure 3 is a schematic showing a side-view of a portion of the vehicle 200 shown in figure 2. The vehicle 200 has a plurality of different regions 302, 304, 306, for example a foot region 302, a face region 304 and a screen region 306. The regions extend between different zones 202, 204, 206. For example, the foot region 302, face region 304 and screen region 306 each extend across the driver zone 202 and the front passenger zone 204, such that each of the regions 302, 34, 306 is shared between the driver zone 202 and front passenger zone 204. In another example one or more of the regions 302, 304, 306 also extends into the rear passenger zone 206 - for example a foot region 302 is shared between the driver zone 202, front passenger zone 204 and rear passenger zone 206. Air is distributed to each region 302, 304, 306 from the HVAC unit 208 by means of one or more vents 301, 303, 305. For example air is distributed from the HVAC unit 208 to the foot region by means of one or more foot vents 301, to the face region by means of one or more face vents 303 and to the screen region by means of one or more screen vents 305. Whilst figure 3 shows vents 301, 303, 305 being present in one particular zone, for example a driver zone 202, it is noted that vents are provided in each of the zones 202, 204, 206 - for example air is distributed to a foot region 302 by one or more foot vents included in the driver zone 202, front passenger zone 204 and rear passenger zone 206. In order to change the air flow distribution, the controller 209 is configured to instruct the HVAC unit 208 to change the proportion of air flowing through the foot vents 301, face vents 303 and screen vents 305 respectively.

Figure 4 shows a method 400 for controlling a vehicle climate system in accordance with the invention. The method 400 is envisaged to be applied to the vehicle 200 described above in relation to figures 2 and 3, and in particular carried out by controller 209.

The method starts at step S402 in which a first target air flow temperature value is determined for a first zone 202 (for example the driver's zone). The determination is based on at least one of: a user-selected temperature setting for the first zone 202 that is transmitted to the controller 209; a sun load (e.g. a thermal load provided by the sun) indicated by the solar sensor 214; and a cabin temperature indicated by the interior temperature sensor 210.

At step S404, a second target air flow temperature value is determined for a second zone 204, 206 (for example a passenger zone). This determination is also based on at least one of: a user-selected temperature setting for the second zone 204, 206 that is transmitted to the controller 209; a sun load (e.g. a thermal load provided by the sun) indicated by the solar sensor 214; and a cabin temperature indicated by the interior temperature sensor 210.

At step S406, it is determined whether the second zone 204, 206 is occupied by a person. In some embodiments the determination involves querying the status of one or more seatbelt sensors 220, 222, 224 present in the second zone 204, 206. For example the seatbelt sensors 220, 222, 224 send a signal to the controller 209 indicating whether the seatbelt associated with each seatbelt sensor 220, 222, 224, is fastened. If the one or more seatbelt sensors 220, 222, 224 indicated that the associated seatbelts are fastened, the controller 209 assumes that the second zone 204, 206 is occupied by a person. If the one or more seatbelt sensors 220, 222, 224 indicated that the associated seatbelts are unfastened, the controller 209 assumes that the second zone 204, 206 is unoccupied.

Alternatively, or in addition, the determination of whether the second zone 204, 206 is occupied in S406, involves receiving a signal from one of the other zone occupancy sensors 226, 228, 230, 232, 234, 236, 238 discussed above. For example the determination may be based on a signal sent to the controller 209 from a pressure sensor 226, 228, 230, wherein the signal indicates the pressure measured by the pressure sensor 226, 228, 230 - if the measured pressure exceeds a pre-determined threshold, the controller 209 assumes that the second zone 204, 206 is occupied by a person; if the measured pressure does not exceeds the pre-determined threshold, the controller 209 assumes that the second zone 204, 206 is unoccupied. Similarly the determination may be based on a signal sent to the controller 209 from a door sensor 234, 236, 238, wherein the signal indicates whether an associated door for the second zone 204, 206 is open - if the signal indicates that a door in the second zone has been open within a predetermined period of time (for example since the last time the vehicle 200 was unlocked/switched on) the controller 209 assumes that the second zone 204, 206 is occupied by a person; if the signal indicates that the door has not been opened within the predetermined period of time, the controller 209 assumes that the second zone 204, 206 is unoccupied.

If the controller 209 determines that the second zone is occupied, the method proceeds to step S407 in which a characteristic of the air flow is calculated based on the target air flow temperature values of both the first and second zones. For example, the air flow distribution between the regions (for example face, foot and screen regions) is calculated based on the target air flow temperature values of both the first and second zones in the known manner, resulting in a compromise distribution as described above. In a further example the air flow rate is calculated based on the target air flow temperature values of both the first and second zones in the known manner (for example based on the difference between a measured cabin temperature and the average of the first and second target air flow temperature values), resulting in a compromise air flow rate as described above.

If the controller 209 determines that the second zone is unoccupied, the method proceeds to step S408 in which a characteristic is calculated based on the target temperature value of the first zone but not the second zone. In this case the second target air flow temperature value is ignored by the controller 209, and the second target air flow temperature value is omitted from calculation of the characteristic. For example, the air flow distribution between the regions (for example face, foot and screen regions) is calculated based only on the target air flow temperature value associated with the first zone 202 (e.g. the driver's zone) and not the target air flow temperature value associated with the second zone 204, 206 (e.g. a passenger's zone). In a further example the air flow rate provided by the HVAC unit 208 is calculated based only on the target air flow temperature value associated with the first zone 202 (e.g. the driver's zone) and not the target air flow temperature value associated with the second zone 204, 206.

In step S410, air flow having the calculated characteristic (e.g. air flow distribution or air flow rate) is provided by the vehicle climate system. For example the controller 209 instructs the HVAC unit 208 to provide the calculated air flow distribution in a manner known in the art (for example by causing the HVAC unit 208 to change the proportion of air flowing through the foot vents 301, face vents 303 and screen vents 305 respectively). In a further example the controller 209 instructs the HVAC unit 208 to provide the calculated air flow rate in a manner known in the art (for example by causing the HVAC unit to use a specific fan speed).

Advantageously, the above method results in improved comfort for persons in a first zone in the vehicle by ensuring that compromise air flow characteristics are only ever used when necessary, i.e. when a person is present in one of the other zones in the vehicle, and automatically optimising the air flow characteristics for the first zone when the one or more other zones are unoccupied regardless of the temperature setting provided in the one other zones. For example driver comfort is improved by automatically optimising air flow distribution and air flow rate for the driver's zone regardless of the target temperature(s) of any other zone(s) in the vehicle if there are no passengers in the vehicle.

In an embodiment, there is provided a computer readable medium (for example a transitory or non-transitory computer readable medium) comprising instructions which, when executed by a computer system present within a vehicle 200 (for example as may form a part of the controller 209), cause at least some and in some embodiments all of the steps of the method 400 above to be performed.

The above embodiments are provided as examples only. Further aspects of the invention will be understood from the appended claims.

Claims

1. A method for controlling a vehicle climate system in a vehicle having at least two zones; the method comprising: determining a first target air flow temperature value for a first zone; determining a second target air flow temperature value for a second zone; determining whether the second zone is occupied; in the event that it is determined that the second zone is unoccupied: calculating at least one characteristic of air flow, wherein the first target air flow temperature value and a measured temperature value are included in the calculation and the second target air flow temperature value is omitted from the calculation; instructing the vehicle climate system to provide an air flow to the first and second zones having the calculated characteristic.

2. The method of claim 1 wherein the at least one characteristic is an air flow rate.

3. The method of claim 1 or claim 2 wherein the at least one characteristic is an air flow distribution over a plurality of regions in the vehicle.

4. The method of any of claims 1 to 3, wherein determining at least one of the first and second target airflow temperature values is based on at least one of: a detected sun load; and a user selected temperature value.

5. The method of any preceding claim, wherein the determining of whether the second zone is occupied by a person comprises querying the status of a seatbelt sensor associated with the second zone.

6. The method of any preceding claim, wherein the determining of whether the second zone is occupied by a person comprises receiving data from a door sensor associated with the second zone.

7. The method of claim 6, wherein the determining of whether the second zone is occupied by a person comprises determining, using the received data, whether a door associated with the door sensor has been opened within a predetermined period of time.

8. The method of claim 7, wherein the determining of whether the second zone is occupied by a person comprises determining, using the received data, whether the door associated with the door sensor has been opened within a predetermined period of time since at least one of: a time at which the door was unlocked; and a time at which the vehicle's ignition was switched on.

9. The method of any preceding claim, wherein the determining of whether the second zone is occupied by a person comprises using at least one of: a pressure sensor in a seat associated with the second zone, a camera, and an infrared detector.

10. The method of any preceding claim wherein the at least two zones comprise a driver zone and a passenger zone.

11. The method of any of claims 3 and claims 4 to 10 when dependent on claim 3 wherein the plurality of regions comprise at least one of a screen region, a face region and a foot region.

12. A vehicle climate system for a vehicle having at least two zones, wherein the vehicle climate system comprises: a controller; and a heating, ventilation and air conditioning unit capable of providing air flow; wherein the controller is configured to: determine a first target air flow temperature value for a first zone; determine a second target air flow temperature value for a second zone; determine whether the second zone is occupied; in the event that it is determined that the second zone is unoccupied: calculate at least one characteristic of air flow, wherein the first target air flow temnerature value and a measured temnerature value are included in the calculation and the second target air flow temperature value is omitted from the calculation; instruct the heating, ventilation and air conditioning unit to provide an air flow to the first and second zones having the calculated characteristic.

13. The vehicle climate system of claim 12 wherein the at least one characteristic is an air flow rate.

14. The vehicle climate system of claim 12 or claim 13 wherein the at least one characteristic is an air flow distribution over a plurality of regions in a vehicle.

15. The vehicle climate system of any of claims 12 to 14, wherein the controller is further configured to: receive a first signal from a first sensor, the first signal indicating a sun load; determine at least one of the first and second target airflow temperature values based on the first signal.

16. The vehicle climate system of any of claims 12 to 15, wherein the controller is configured to: receive a user input indicating a desired temperature; determine at least one of the first and second target airflow temperature values based on the user input.

17. The vehicle climate system of any of claims 12 to 16, wherein the controller is configured to receive a further signal from a second sensor, the further signal indicating whether the second zone is occupied.

18. A vehicle comprising: at least two zones; a plurality of regions associated with the zones; and the vehicle climate system of any of claims 12 to 17.

19. The vehicle of claim 18 when dependent on claim 17, wherein the second sensor comprises a seatbelt sensor associated with associated with the second zone.

20. The vehicle of claim 18 or claim 19 when dependent on claim 17, wherein the second sensor comprises a door sensor associated with the second zone.

21. The vehicle of claim 20, wherein the controller is configured to determine whether the second zone is occupied by a person by determining, using the second signal, whether a door associated with the door sensor has been opened within a predetermined period of time.

22. The vehicle of claim 21, wherein the controller is configured to determine whether the second zone is occupied by a person by determining, using the second signal, whether the door associated with the door sensor has been opened within a predetermined period of time since at least one of: a time at which the door was unlocked; and a time at which the vehicle's ignition was switched on.

23. The vehicle of any of claims 19 to 22, or claim 18 when dependent on claim 17, wherein the second sensor comprises at least one of a pressure sensor in a seat associated with the second zone, a camera, and an infrared detector.

24. The vehicle of any of claims 18 to 23 wherein the at least two zones comprise a driver zone and a passenger zone.

25. The vehicle of any of claims 18 to 23 when dependent on claim 14 wherein the plurality of regions comprises at least one of a screen region, a face region and a foot region.