Air conditioning unit and motor vehicle with such an air conditioning unit

Abstract

The present invention relates to an air conditioning unit (1) for a motor vehicle (2). The essential aspect of the invention is that the air conditioning unit (1) is designed as a modular unit and comprises at least the following components: - a fresh air duct (4) and a fluidically separated recirculated air duct (5), - a blower (12) through which both fresh air (6) in the fresh air duct (4) and recirculated air (7) in the recirculated air duct (5) can be conveyed, - an evaporator (15) for cooling the recirculated air (7) in the recirculated air duct (5) and for cooling the fresh air (6) in the fresh air duct (4), - a heating device (18) for heating the recirculated air (7) in the recirculated air duct (5) and for heating the fresh air (6) in the fresh air duct (4), - a dehumidification device (21) which is arranged in the recirculation duct (5) and is designed to dehumidify the recirculated air (7). This allows for the provision of a space-optimized, energy-saving and cost-effective air conditioning unit (1).

Description

[0001] The present invention relates to an air conditioning unit for a motor vehicle, according to the preamble of claim 1. The invention further relates to a motor vehicle with such an air conditioning unit.

[0002] DE 10 2010 035 740 A1 discloses an air conditioning system for a motor vehicle in which, in at least one operating state, a fresh air stream can be conveyed in a first stream and, simultaneously, a recirculated air stream can be conveyed in a second stream that is hydraulically separated from the first stream. An evaporator is arranged in the recirculated air stream, with the fresh air stream flowing into the recirculated air stream upstream of the evaporator, bypassing the evaporator.

[0003] WO 2019 / 069 579 A1 discloses a device for humidity control with an adsorber. Switching elements allow switching between an adsorption mode and a desorption mode.

[0004] JP 2003-291625A discloses an air conditioning system for vehicles with a housing in which an interior air duct is formed, including an interior heat exchanger for heat radiation, an interior heat exchanger for heat absorption, an outside air inlet, an interior air inlet, a floor fan, a heating duct connected to the interior heat exchanger, a heating bypass duct bypassing the interior heat exchanger, and an air mixing flap for switching the air duct of the heating duct and the heating bypass duct. The air conditioning system is also equipped with an evaporative air duct through which the outside air introduced into the interior air duct is directed to the interior heat exchanger for heat absorption, and with an air bypass duct through which the outside air introduced into the interior air duct bypasses the interior heat exchanger.

[0005] US Patent 2019 / 0 092 143 A1 discloses a vehicle air conditioning system in which a flow channel arranged downstream of a temperature control device branches into a first flow channel and a second flow channel. The first flow channel includes a windshield-side flow channel connected to a windshield-side air outlet opening and an adsorbent-side flow channel connected to an adsorbent inlet section.

[0006] DE 10 2010 022 441 A1 discloses a motor vehicle interior air treatment device with a fresh air / recirculated air switch, the fresh air inlet of which is connected to the outside air and the recirculated air inlet of which is connected to a dehumidifier.

[0007] US patent 2022 / 0144046A1 discloses an air conditioning system for electric vehicles. The thermal load on the air conditioning system is reduced through the use of desiccant-coated heat exchangers. Energy efficiency is improved by utilizing the waste heat generated during the cooling of an electronic device when the desiccant-coated heat exchanger is regenerated.

[0008] When air conditioning a passenger compartment in a motor vehicle, especially a battery-electric vehicle, the aim is to minimize unnecessary energy consumption in order to maximize driving range. However, heating operation, particularly in cold ambient temperatures, is extremely energy-intensive because, unlike vehicles with combustion engines, very little waste heat can be utilized.

[0009] For this reason, it is desirable to use as much recirculated air from the passenger compartment as possible to minimize unnecessary heating of fresh air drawn in from outside. However, using recirculated air from the passenger compartment is only possible to a limited extent, as the vehicle occupants release moisture that can lead to an increased risk of window fogging, at least in the medium term.

[0010] For this reason, air conditioning units with dehumidification devices, i.e. drying devices, are already known in order to dry or dehumidify the air taken from a passenger compartment before it is returned to the passenger compartment and thereby at least reduce the risk of windows fogging up.

[0011] However, a disadvantage of the air conditioning units known from the state of the art is their comparatively large installation space requirement and the associated comparatively high costs.

[0012] The present invention therefore deals with the problem of providing an improved or at least an alternative embodiment for an air conditioning device of the generic type, by means of which the disadvantages known from the prior art can at least be reduced.

[0013] This problem is solved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0014] The present invention is based on the general concept of designing, for the first time, a known air conditioning unit with a heating element and evaporator, and a previously spatially separate dehumidification unit (i.e., drying unit), as a combined unit in which the evaporator, heating element, and dehumidification unit are integrated in a common housing. The air conditioning unit according to the invention for a motor vehicle has a recirculating air duct and a fluidically separate fresh air duct. Fresh air from outside can be supplied to a passenger compartment via the fresh air duct, while air drawn from the passenger compartment via the recirculating air duct is processed in the air conditioning unit, for example, dehumidified, heated, or cooled, and then supplied back to the passenger compartment.Furthermore, a blower is provided, which can convey both fresh air in the fresh air duct and recirculated air in the recirculated air duct. Such a blower can, for example, have two blower units, a first blower unit in the fresh air duct and a separate or functionally connected second blower unit in the recirculated air duct. This makes it possible to convey both fresh air in the fresh air duct and recirculated air in the recirculated air duct by means of the blower units, whereby, of course, by switching off or reducing the speed of one of the two blower units, only fresh air in the fresh air duct or only recirculated air in the recirculated air duct can be conveyed. The air conditioning unit according to the invention also has an evaporator for cooling the recirculated air in the recirculated air duct and for cooling the fresh air in the fresh air duct.It is also conceivable that the evaporator has two evaporator units, a first evaporator unit being arranged in the fresh air duct and a second evaporator unit being arranged in the recirculated air duct. The first and second evaporator units can be operated independently. The air conditioning unit according to the invention also has a heating device for heating the recirculated air in the recirculated air duct and for heating the fresh air in the fresh air duct. Here, too, it is conceivable that the heating device has two heating units, a first heating unit being arranged in the fresh air duct and a second heating unit being arranged in the recirculated air duct, whereby either or alternatively fresh air in the fresh air duct and / or recirculated air in the recirculated air duct can be heated. Furthermore, a dehumidification device, i.e., a drying device, is arranged in the recirculated air duct, which is designed to dehumidify the recirculated air.Since the fresh air in the fresh air duct is usually relatively dry and therefore does not need to pass through the dehumidification unit, the dehumidification unit can be located entirely within the recirculation duct and used there to dry the air drawn in from the passenger compartment. This allows for increased recirculation operation with lower energy consumption, especially at cold outside temperatures, without increasing the risk of window fogging, as the dehumidification unit located in the recirculation duct removes the moisture emitted by the vehicle occupants in the passenger compartment into the surrounding environment.

[0015] By combining the fan, evaporator, heating unit, dehumidification unit, and recirculation / fresh air duct into the air conditioning unit according to the invention, it can be equipped with a common housing. This not only reduces the number of parts but also, consequently, storage, logistics, and assembly costs. Furthermore, such a combined air conditioning unit allows for a significantly more compact design, thus saving valuable installation space, which is already limited in modern vehicles.

[0016] However, the greatest advantage of the air conditioning device according to the invention lies in the fact that it allows for the use of an increased proportion of recirculated air, especially at cold ambient temperatures, thereby saving considerable energy compared to heating fresh air drawn in from the outside and comparatively cold air.

[0017] In an advantageous embodiment of the air conditioning unit according to the invention, the recirculation duct is arranged below the fresh air duct in the installed state. This makes it possible to position the fresh air duct, which is usually connected to ventilation nozzles and / or defrost nozzles, i.e., an upper area of ​​the passenger compartment, correctly in relation to the recirculation duct, which is usually connected to footwell nozzles and / or rear air vents. Such a dual-layer arrangement also allows the fresh air duct to be preferably connected to ventilation nozzles located on the dashboard and / or below the windshield, so that the vehicle occupants in the passenger compartment are always supplied with fresh air in the head area. Since the fresh air drawn in from outside also typically has a lower humidity level, this effectively prevents the windows from fogging up.By positioning the recirculating air duct below the fresh air duct, the dehumidification unit located within the recirculating air duct can be more easily connected to the surrounding environment via a drain. This allows for the simple disposal of the water separated from the recirculated air without having to bypass a fresh air duct located, for example, below the recirculating air duct. Alternatively, the dehumidification unit could be designed in two stages: a first stage for dehumidifying the recirculated air and a second stage for removing the water.

[0018] In a further advantageous embodiment of the air conditioning unit according to the invention, the dehumidification unit is arranged upstream of the heating unit. This offers the significant advantage that already dehumidified air is heated by the heating unit, which is considerably more energy-efficient compared to heating humid air.

[0019] In a further advantageous embodiment of the air conditioning unit according to the invention, the dehumidification unit is arranged upstream of the evaporator. This makes it possible to pre-dehumidify the recirculated air supplied to the evaporator as well as the recirculated air supplied to the heating unit, thereby reducing condensation in the evaporator and increasing the efficiency of the heating unit. This allows the entire air conditioning unit to be operated much more energy-efficiently.

[0020] In a particularly preferred embodiment of the air conditioning unit according to the invention, a first bypass channel bypassing a first heating unit of the heating device is arranged in the fresh air duct. This bypass channel includes a first guide device for dividing the fresh air flow between the first heating unit of the heating device and the first bypass channel. Specifically, this means that the heating device with a first heating unit is arranged in the fresh air duct, and a first bypass channel is provided for this first heating unit. The first guide device, which may, for example, comprise an adjustable slide or a rotatable or adjustable flap, allows the fresh air flow to be divided between the first heating unit of the heating device and the bypass channel bypassing the first heating unit.If, for example, heating the fresh air is not desired, the first heating unit of the heating system in the fresh air duct can be switched off and the first guide device adjusted so that the entire fresh air flow bypasses the first heating unit in the fresh air duct. Of course, a portion of the fresh air flow can also pass through the first heating unit; however, if the fresh air flow is entirely routed through the first bypass duct, pressure loss can be reduced.

[0021] In a particularly preferred embodiment of the air conditioning unit according to the invention, a second bypass channel bypassing the heating element or a second heating unit of the heating element is arranged in the recirculating air duct. This second bypass channel includes a second guide device for dividing the recirculated air flow between the second heating unit of the heating element and the second bypass channel. The second guide device can also, for example, have an adjustable slide or a rotatable or adjustable flap, which is adjusted by means of a corresponding drive, analogous to the first guide device. The second guide device thus also makes it possible, if heating of the recirculated air flowing in the recirculating air duct is not desired, to direct the air flowing in the duct completely through the second bypass channel and thereby reduce the pressure loss occurring in the recirculating air duct.

[0022] The present invention is further based on the general concept of equipping a motor vehicle with a passenger compartment and an air conditioning unit described in the preceding paragraphs, thereby transferring the advantages described with respect to the air conditioning unit according to the invention to the motor vehicle according to the invention. Specifically, these advantages lie in a significantly reduced installation space requirement due to the design of the air conditioning unit with evaporator, heating element, fan, and dehumidification unit as a single unit. This allows, for example, a housing comprising the recirculating air duct and the fresh air duct to be designed as a single-piece, and in particular even as a one-piece, component, for example, as an injection-molded plastic part.Due to the compact design of the air conditioning unit according to the invention, the dehumidification unit is not housed in a separate casing and installed separately in the vehicle, as was previously the case. A further major advantage of the air conditioning unit according to the invention is that the dehumidification unit, arranged in the recirculation duct, can dry recirculated air taken from the passenger compartment and humidified by the vehicle occupants, and then return it to the passenger compartment for temperature control. This allows the proportion of recirculated air to be significantly increased, which contributes to substantial energy savings, particularly at cold outside temperatures.

[0023] The vehicle is expediently designed as an electric vehicle. Particularly in electrically powered vehicles, cold outside temperatures not only place increased demands on the battery, but also result in increased energy consumption for heating the passenger compartment, which negatively impacts the achievable range. The air conditioning unit according to the invention makes it possible to dry the recirculated air extracted from the passenger compartment by means of the dehumidification device arranged in the recirculation duct and to supply it back to the passenger compartment at a pre-heated temperature, and in particular, at a pre-heated temperature. The dehumidification device and the resulting drying of the recirculated air not only reduce condensation in the evaporator, but also increase the efficiency of the heating system, since significantly more energy is required to heat humid air than to heat dry air.

[0024] Further important features and advantages of the invention will become apparent from the dependent claims, the drawing and the associated description of the figures based on the drawing.

[0025] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention. Components of a higher-level unit, such as a device, apparatus, or arrangement, mentioned above and those to be mentioned below, which are designated separately, can form separate parts or components of this unit or be integral areas or sections of this unit, even if this is depicted differently in the drawing.

[0026] A preferred embodiment of the invention is shown in the drawing and is explained in more detail in the following description.

[0027] The only Fig. Figure 1 shows a cross-sectional view through an air conditioning device according to the invention of a motor vehicle according to the invention.

[0028] According to the Fig. Figure 1 comprises an air conditioning unit 1 according to the invention, which can be arranged in a motor vehicle 2 according to the invention, in particular an electric vehicle 3, and comprises a fresh air duct 4 and a recirculation duct 5. Fresh air 6 drawn in from an environment 9 flows into the fresh air duct 4, while recirculated air 7 drawn in from a passenger compartment 8 flows into the recirculation duct 5. The recirculation duct 5 is fluidically separated from the fresh air duct 4, for example by a partition 10, which can be part of a common housing 11.

[0029] Furthermore, the air conditioning unit 1 according to the invention has a blower 12, which can supply both fresh air 6 in the fresh air duct 4 and recirculated air 7 in the recirculated air duct 5. For this purpose, the blower 12 can, for example, have a first blower unit 13 and a second blower unit 14, wherein the first blower unit 13 is arranged in the fresh air duct 4 and the second blower unit 14 is arranged in the recirculated air duct 5. The two blower units 13, 14 can be operated independently of each other, so that the supply of fresh air 6 can take place independently of the supply of recirculated air 7.

[0030] Furthermore, an evaporator 15 is provided for cooling the recirculated air 7 in the recirculated air duct 5 and for cooling the fresh air 6 in the fresh air duct 4. Analogous to the blower 12, the evaporator 15 can also have a first evaporator unit 16, which is arranged in the fresh air duct 4 and is designed exclusively for cooling the fresh air 6, as well as a second evaporator unit 17, which is arranged in the recirculated air duct 5 and is designed exclusively for cooling the recirculated air 7.

[0031] Furthermore, the air conditioning unit 1 according to the invention comprises a heating device 18, which in turn may include a first heating unit 19 arranged in the fresh air duct 4 and a second heating unit 20 arranged in the recirculated air duct 5. This allows for independent heating of the fresh air 6 and the recirculated air 7. A dehumidification device 21 is also provided, which is arranged only in the recirculated air duct 5 and serves to dehumidify the recirculated air 7 taken from the passenger compartment 8. The dehumidification device 21 arranged in the recirculated air duct 5 makes it possible to dry the air humidified by the vehicle occupants in the passenger compartment 8 and thereby supply it back to the passenger compartment 8 without having to accept an increased risk of window fogging.Since the fresh air 6 drawn in from the environment 9 usually has a significantly lower moisture content, the dehumidification device 21 does not need to be placed in the fresh air duct 4, which saves costs.

[0032] In purely theoretical terms, it is of course also conceivable that the dehumidification device 21 also has two dehumidification units, of which a first dehumidification unit is arranged in the fresh air duct 4 and a second dehumidification unit in the recirculated air duct 5, which also makes it possible to dehumidify potentially moist fresh air 6.

[0033] As can be further seen, the evaporator 15 is arranged upstream of the heating device 18, while the dehumidification device 21 is arranged upstream of the evaporator 15. All of the aforementioned components 21, 15 and 18 are arranged downstream of the blower 12.

[0034] By integrating the blower 12, the evaporator 15, the heating unit 18 and the dehumidification unit 21 into a common housing 11, not only can the required installation space be significantly reduced, but a separate housing for a separately arranged dehumidification unit can also be eliminated, resulting in considerable cost savings.

[0035] If one considers the Fig. 1. Further, it can be seen that the recirculation duct 5 is located below the fresh air duct 4 and is connected to the passenger compartment 8 at its outlet, for example via footwell vents 22 and / or rear vents 23. The fresh air duct 4, in turn, is connected to ventilation vents 24 and / or defrost vents 25. The relatively dry fresh air 6 from the surroundings 9 can thus be discharged in the area of ​​the dashboard or windshield, thereby reducing the risk of windshield fogging and supplying fresh air to the head area of ​​the vehicle occupants. Conditioned recirculated air 7 can be supplied to the passenger compartment 8 via the footwell vents 22 or the rear vents 23 in a lower area where vehicle occupants do not typically breathe.

[0036] According to the Fig.In the fresh air duct 4, a first bypass duct 26 bypasses the first heating unit 19 of the heating device 18. This bypass duct 26 includes a first guide device 27 for dividing the fresh air flow between the first heating unit 19 and the first bypass duct 26. The first guide device 27 can, for example, have a slide or a flap, thereby completely closing or opening the bypass duct 26 as needed. If, for example, heating the passenger compartment 8 is not desired, the first guide device 27, with its slide or flap, can completely cover the first heating unit 19 of the heating device 18, causing the entire fresh air flow to pass exclusively through the first bypass duct 26 and thus reducing pressure loss.

[0037] Similarly, a second bypass channel 28 bypassing the second heating unit 20 of the heating device 18 can also be arranged in the recirculation duct 5, with a second guide device 29 for dividing a recirculation flow between the second heating unit 20 of the heating device 18 and the second bypass channel 28. The second guide device 29 can also have an adjustable slide and / or an adjustable or rotatable flap.

[0038] The air conditioning unit 1 according to the invention allows for a particularly compact design, since the dehumidification unit, which was previously often arranged separately, is now an integral part of the air conditioning unit 1. Furthermore, by arranging the dehumidification unit 21 exclusively in the recirculation duct 5, a separate dehumidification unit in the fresh air duct 4 is unnecessary, as the fresh air 6 drawn in from the environment 9 typically has a significantly lower moisture content and does not require dehumidification. With the dehumidification unit 21 arranged in the recirculation duct 5, the recirculated air 7 can be treated and returned to the passenger compartment 8 without increasing the risk of window fogging. This allows for a higher proportion of recirculated air to be used when temperature-controlling the passenger compartment 8, particularly in cold weather conditions, which in turn enables energy-efficient operation of the motor vehicle 2 according to the invention.This is particularly advantageous if the motor vehicle 2 according to the invention is an electric vehicle 3, in which the range can thereby be increased. Reference symbol list 1. Air conditioning unit 2. Motor vehicle 3. Electric vehicle 4. Fresh air duct 5. Recirculation duct 6. Fresh air 7. Recirculated air 8. Passenger compartment 9. Surroundings 10. Partition wall 11. Housing 12. Blower 13. First blower unit 14. Second blower unit 15. Evaporator 16. First evaporator unit 17. Second evaporator unit 18. Heating system 19. First heating unit 20. Second heating unit 21. Dehumidification unit 22. Footwell jets 23. Rear jets 24. Air vents 25. Defrost vents 26. First bypass channel 27. First guidance system 28. Second bypass channel 29. Second guidance system

Claims

Air conditioning unit (1) for a motor vehicle (2), characterized in that the air conditioning unit (1) is designed as a modular unit and comprises at least the following components: - a fresh air duct (4) and a fluidically separated recirculated air duct (5), - a blower (12) through which both fresh air (6) in the fresh air duct (4) and recirculated air (7) in the recirculated air duct (5) can be conveyed, - an evaporator (15) for cooling the recirculated air (7) in the recirculated air duct (5) and for cooling the fresh air (6) in the fresh air duct (4), - a heating device (18) for heating the recirculated air (7) in the recirculated air duct (5) and for heating the fresh air (6) in the fresh air duct (4), - a dehumidification device (21) which is arranged in the recirculated air duct (5) and is designed to dehumidify the recirculated air (7). Air conditioning unit (1) according to claim 1, characterized in that the recirculating air duct (5) is arranged below the fresh air duct (4) in the installed state. Air conditioning unit (1) according to claim 1 or 2, characterized in that the dehumidification device (21) is arranged upstream of the heating device (18). Air conditioning unit (1) according to one of the preceding claims, characterized in that the dehumidification device (21) is arranged upstream of the evaporator (15). Air conditioning unit (1) according to one of the preceding claims, characterized in that a first bypass channel (26) bypassing a first heating unit (19) of the heating device (18) with a first guide device (27) for dividing a fresh air flow between the first heating unit (19) of the heating device (18) and the first bypass channel (26) is arranged in the fresh air duct (4). Air conditioning unit (1) according to claim 5, characterized in that the first guide device (27) has a slide or a flap. Air conditioning unit (1) according to one of the preceding claims, characterized in that a second bypass channel (28) bypassing a second heating unit (20) of the heating device (18) with a second guide device (29) for dividing a recirculated air flow between the second heating unit (20) of the heating device (18) and the second bypass channel (28) is arranged in the recirculated air channel (5). Air conditioning unit (1) according to claim 7, characterized in that the second guide device (29) has a slide or a flap. Air conditioning unit (1) according to one of the preceding claims, characterized in that the fresh air duct (4) is communicatively connected to ventilation nozzles (24) and / or defrost nozzles (25). Air conditioning unit (1) according to one of the preceding claims, characterized in that the recirculation duct (5) is connected to footwell nozzles (22) and / or rear nozzles (23) in a communicating manner. Motor vehicle (2) with a passenger compartment (8) and an air conditioning unit (1) according to one of the preceding claims. Motor vehicle (2) according to claim 11, characterized in that the motor vehicle (2) is designed as an electric vehicle (3).

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