Method for controlling an air conditioning unit with adaptive learning pilot control unit and electrically driven motor vehicle with such an air conditioning unit

Abstract

Method for controlling an air conditioning unit (10) of an electrically driven motor vehicle, wherein the air conditioning unit (10) is designed with an evaporator (14) for cooling air which is passed through a cold path (16) of the air conditioning unit (10); a heating register (18) for heating air which is passed through a warm path (20) of the air conditioning unit (10), wherein the first heat exchanger (14) and the second heat exchanger (18) are integrated in a refrigerant circuit (22), an additional heating element (24) arranged in the warm path (20) downstream of the second heat exchanger (18) for further heating the air, several movable temperature flaps (26, 28), and an adaptive learning feedforward control unit (34); the method comprising the following steps: Providing conveyed cooled air downstream of the first heat exchanger (14) and conveyed heated air downstream of the additional heating element (24), adjusting the temperature flaps (26, 28) such that an air outlet temperature of a conditioned air (kL) at an outlet (30) directed towards a footwell in the motor vehicle is greater by a target temperature difference than an air outlet temperature of the conditioned air (kL) at an outlet (32) directed towards an upper body space in the motor vehicle, characterized in that in the method, the additional heating element (24) and the temperature flaps (26, 28) are controlled based on at least two detected boundary condition values ​​(RW1, RW2) by means of the pilot control unit (34) such that the target temperature difference is adjusted, wherein the additional heating element (24) and the temperature flaps (26, 28) are set directly to a stored respective setting value (EWA; EWB; EWx), from which it is known due to an adaptive learning phase that the achievement of the target temperature difference is ensured and wherein stored, previously learned setting values ​​(EWA, EWB) are adapted based on a learning phase during operation of the motor vehicle.

Description

[0001] The invention relates to a method according to the preamble of claim 1 for controlling an air conditioning unit. The air conditioning unit can be configured to supply conditioned air to the interior of an electrically powered motor vehicle and can be designed with: a first heat exchanger, in particular an evaporator, for cooling air that is passed through a cold path of the air conditioning unit; a second heat exchanger, in particular a heating register, for heating air which is passed through a warm path of the air conditioning unit, wherein the first heat exchanger and the second heat exchanger are integrated in a refrigerant circuit, an additional heating element arranged in the warm path downstream of the second heat exchanger for further heating the air, and with a plurality of movable temperature flaps configured to provide cooled air conveyed downstream of the first heat exchanger and heated air conveyed downstream of the additional heating element such that an air outlet temperature of the conditioned air at an outlet vent directed toward a footwell in the motor vehicle, in particular a foot outlet, is greater by a target temperature difference than the air outlet temperature of the conditioned air at an outlet vent directed toward an upper body area in the motor vehicle, in particular a head outlet. The invention further relates to an electric motor vehicle with such an air conditioning unit.

[0002] Such a method is known, for example, from DE 10 2020 205 246 A1.

[0003] From DE 10 2010 000 727 A1 a method and a device for climate control for an interior of a motor vehicle are known, in which input data of temperature differences at outlet nozzles are taken into account.

[0004] DE 10 2008 026 354 A1 discloses an automatic climate control system for a motor vehicle that can learn optimal settings.

[0005] Furthermore, for further information on the state of the art, reference is made to DE 10 2017 202 872 A1, DE 10 2006 027 995 A1, DE 10 2009 059 983 A1 and DE 10 2019 124 054 A1.

[0006] In conventional air conditioning systems, heated air and unheated air are mixed in a mixing chamber using so-called mixing flaps or temperature flaps to achieve a stratification effect. The air from the foot vents should be warmer than the air from the head vents, as this is known to be more comfortable for the occupants. To achieve such stratification at a desired temperature, the auxiliary heating element in the heating path must regulate a specific temperature using several temperature sensors. The setpoint for this temperature is iteratively adjusted so that the target temperature is reached with the desired stratification.

[0007] Such a rule-based process requires constant readjustment, which requires temperature control with temperature sensors. Accordingly, the control process is rather complex and slow or sluggish, so it takes a long time to find the right setting and adjust the target temperature accordingly.

[0008] The object underlying the invention is to provide a method for controlling an air conditioning unit which enables quick and efficient adjustment in order to achieve a desired temperature stratification.

[0009] This object is achieved by a method for controlling an air conditioning unit and an electrically powered motor vehicle having the features of the respective independent patent claim. Advantageous embodiments with expedient further developments are specified in the dependent patent claims.

[0010] The invention therefore proposes an air conditioning unit which is designed to supply conditioned air to the interior of an electrically driven motor vehicle, comprising a first heat exchanger, in particular an evaporator, for cooling air which is passed through a cold path of the air conditioning unit; a second heat exchanger, in particular a heating register, for heating air which is passed through a warm path of the air conditioning unit, wherein the first heat exchanger and the second heat exchanger are integrated in a refrigerant circuit, an additional heating element arranged in the warm path downstream of the second heat exchanger for further heating the air, and with a plurality of movable temperature flaps which are configured to provide cooled air conveyed downstream of the first heat exchanger and heated air conveyed downstream of the additional heating element in such a way that an air outlet temperature of the conditioned air at an outlet directed towards a footwell in the motor vehicle, in particular a foot outlet, is greater by a target temperature difference than the air outlet temperature of the conditioned air at an outlet directed towards an upper body space in the motor vehicle, in particular a head outlet.It is provided that it is further designed with an adaptive learning pilot control unit which is designed to control the additional heating element and / or the temperature flaps based on at least two detected boundary condition values ​​in such a way that the target temperature difference is set.

[0011] Using such a pilot control unit, it is possible to adjust the auxiliary heating element and / or the temperature dampers to the desired positions, based on boundary condition values ​​derived from previously learned parameters, essentially directly and without an iterative process. This eliminates the need for specific temperature sensors assigned to the auxiliary heating element, simplifying the design and saving costs. Furthermore, the desired temperature difference can be adjusted more quickly than through an iterative control process.

[0012] For the air conditioning unit, the boundary condition values ​​can be selected from a group of values ​​recorded before or during operation of the vehicle: ambient temperature, air mass flow in the air conditioning unit, target temperature in the vehicle interior, air outlet temperature after the first heat exchanger, air outlet temperature after the second heat exchanger, and air outlet temperature after the auxiliary heating element. Such values ​​are typically available in a higher-level vehicle control unit and can be used for pre-control of the auxiliary heating element. The values ​​mentioned here are examples and can be combined as desired, allowing the desired result to be quickly achieved when setting the target temperature difference.

[0013] For the air conditioning unit, the target temperature difference can be 8 K to 16 K, in particular 10 K to 14 K, preferably 12 K. A target temperature difference in these ranges is perceived as pleasant by most people or vehicle occupants in the vehicle interior, which is the case both in colder and warmer ambient temperatures.

[0014] In the air conditioning unit, the pilot control unit can have a memory unit configured to store boundary condition values ​​and associated setting values ​​for the auxiliary heating element and / or the temperature flaps. The boundary condition values ​​and setting values ​​can be stored, for example, in a type of map or table. This allows for rapid access to discrete values ​​to achieve rapid adjustment of the target temperature difference.

[0015] In the air conditioning unit, the pilot control unit can be configured to set the additional heating element and / or the temperature flaps directly to a respective setting value stored in the memory unit, which is known, due to an adaptive learning phase, to ensure that the target temperature difference is achieved.

[0016] In the air conditioning unit, the pilot control unit can be configured to adapt previously learned setting values ​​stored in the memory unit based on a learning phase during operation of the motor vehicle. This ensures that, for example, a basic setting existing upon delivery of a motor vehicle can be improved through further learning during operation of the motor vehicle.

[0017] In the air conditioning unit, the pilot control unit can further be configured to store additional setting values ​​based on a learning phase during operation of the motor vehicle, while retaining previously stored setting values. This allows not only a basic setting to be adjusted, but also, for example, additional setting values ​​to be included in a map or table.

[0018] Also proposed is an electrically powered motor vehicle with a refrigeration system and an air conditioning unit as described above. The pilot control unit of the air conditioning unit can be part of a computer unit assigned to the motor vehicle. The first and second heat exchangers can be connected to the refrigeration system of the motor vehicle.

[0019] It is additionally pointed out that the features mentioned above in connection with the air conditioning unit and the pilot control unit form the basis for the method according to the invention for controlling the air conditioning unit.

[0020] Further advantages and details of the invention will become apparent from the following description of embodiments with reference to the figures. Fig. 1 shows a simplified and schematic view of an air conditioning unit for an electrically powered motor vehicle.

[0021] In Fig. 1 shows a simplified and schematic representation of an air conditioning unit 10 for an electrically powered motor vehicle.

[0022] The air conditioning unit 10 is designed to supply conditioned air kL to an interior 12 of the motor vehicle, which is illustrated by the two curved contour arrows.

[0023] The air conditioning unit comprises a first heat exchanger 14, in particular an evaporator, for cooling air that is passed through a cold path 16 of the air conditioning unit 10. Furthermore, the air conditioning unit has a second heat exchanger 18, in particular a heating register, for heating air that is passed through a warm path 20 of the air conditioning unit 10.

[0024] The cold path 16 and the warm path 20 are implemented by corresponding ducts or pipes in the air conditioning unit. Air exiting the first heat exchanger 14, which is usually cooled and dehumidified, can be directed into either the cold path 16 or the warm path 20.

[0025] The first heat exchanger 14 and the second heat exchanger 18 are integrated into a refrigerant circuit 22, which is illustrated here only as a dash-dotted connecting line.

[0026] In the warm path 20, downstream of the second heat exchanger 18, at least one additional heating element 24 is arranged for further heating the air.

[0027] Furthermore, the air conditioning unit 10 comprises a plurality of movable temperature flaps 26, 28 which are designed to provide cooled air conveyed downstream of the first heat exchanger 14 and heated air conveyed downstream of the additional heating element 24 in such a way that an air outlet temperature of the conditioned air at an outlet 30, in particular a foot outlet, directed towards a footwell in the motor vehicle is greater by a target temperature difference than the air outlet temperature of the conditioned air at an outlet 32, in particular a head outlet, directed towards an upper body space in the motor vehicle.

[0028] The air conditioning unit 10 is further designed with an adaptive learning pilot control unit 34, which is configured to control the additional heating element 24 and / or the temperature flaps 26, 28 based on at least two detected boundary condition values ​​RW1, RW2 in such a way that the target temperature difference is set.

[0029] For the air conditioning unit 10, the boundary condition values ​​RW1, RW2 can be selected from a group of values ​​recorded during operation of the motor vehicle. For example, the boundary condition values ​​can relate to the following parameters: ambient temperature, air mass flow in the air conditioning unit 10, target temperature in the vehicle interior 12, air outlet temperature after the first heat exchanger 14, air outlet temperature after the second heat exchanger 18, and air outlet temperature after the additional heating element 24.

[0030] For this purpose, various sensors can be used on the vehicle. For example, corresponding temperature and / or pressure sensors t1 / p1, t2 / p2, t3 / p3 are illustrated for the air conditioning unit 10.

[0031] In the air conditioning unit 10, the pilot control unit 34 is particularly configured to adjust the target temperature difference such that it assumes a value of 8 K to 16 K, in particular 10 K to 14 K, preferably 12 K. In other words, the air flowing from the foot vent 30 into the interior 12 of the motor vehicle is 8 K to 16 K warmer than the air flowing from a head vent 32 into the interior 12. A temperature difference of 10 K to 14 K, and in particular 12 K, was perceived as particularly pleasant for vehicle occupants.

[0032] The pilot control unit 34 can have a storage unit 36 ​​configured to store boundary condition values ​​RW1, RW2 and associated setting values ​​EWA, EWB for the additional heating element 24 and / or for the temperature flaps 26, 28. The pilot control unit 34 is configured to directly adjust the additional heating element 24 and / or the temperature flaps 26, 28 to a respective setting value EWA, EWB stored in the storage unit 36, which is known, based on an adaptive learning phase, to ensure that the target temperature difference is achieved.

[0033] The pilot control unit 34 can further be configured to adapt previously learned setting values ​​EWA, EWB stored in the memory unit 36 ​​based on a learning phase during operation of the motor vehicle. This can, for example, result in a setting value EWA1 that is used instead of the setting value EWA.

[0034] The pilot control unit 34 can further be configured to store supplementary setting values ​​EWx based on a learning phase during operation of the motor vehicle while retaining previously stored setting values ​​EWA, EWB. Such a supplementary setting value EWx can, for example, be assigned to a further boundary condition or combination of boundary conditions RWn.

[0035] As already mentioned in the introduction, an electrically powered motor vehicle, represented here by its interior 12, can be equipped with a refrigeration system 22 and an air conditioning unit 10 described above. The pilot control unit 34 can be part of a computer unit associated with the motor vehicle, not shown here.

Claims

[1] Method for controlling an air conditioning unit (10) of an electrically driven motor vehicle, wherein the air conditioning unit (10) is designed with an evaporator (14) for cooling air which is passed through a cold path (16) of the air conditioning unit (10); a heating register (18) for heating air which is passed through a warm path (20) of the air conditioning unit (10), wherein the first heat exchanger (14) and the second heat exchanger (18) are integrated in a refrigerant circuit (22), an additional heating element (24) arranged in the warm path (20) downstream of the second heat exchanger (18) for further heating the air, several movable temperature flaps (26, 28), and an adaptive learning feedforward control unit (34); the method comprising the following steps: Providing conveyed cooled air downstream of the first heat exchanger (14) and conveyed heated air downstream of the additional heating element (24), adjusting the temperature flaps (26, 28) such that an air outlet temperature of a conditioned air (kL) at an outlet (30) directed towards a footwell in the motor vehicle is greater by a target temperature difference than an air outlet temperature of the conditioned air (kL) at an outlet (32) directed towards an upper body space in the motor vehicle characterized by that in the method, the additional heating element (24) and the temperature flaps (26, 28) are controlled based on at least two detected boundary condition values ​​(RW1, RW2) by means of the pilot control unit (34) in such a way that the target temperature difference is set, wherein the additional heating element (24) and the temperature flaps (26, 28) are set directly to a stored respective setting value (EWA; EWB; EWx), from which it is known due to an adaptive learning phase that the achievement of the target temperature difference is ensured and wherein stored, previously learned setting values ​​(EWA, EWB) are adapted based on a learning phase during operation of the motor vehicle. [2] Method according to claim 1, characterized by that the boundary condition values ​​(RW1, RW2) are selected from a group of values ​​recorded during operation of the motor vehicle: ambient temperature, air mass flow in the air conditioning unit (10), target temperature in the vehicle interior, air outlet temperature after the first heat exchanger (14), air outlet temperature after the second heat exchanger (18), and air outlet temperature after the additional heating element (24). [3] Method according to claim 1 or 2, characterized bythat the target temperature difference is 8 K to 16 K, in particular 10 K to 14 K, preferably 12 K. [4] Method according to one of the preceding claims, characterized by that the boundary condition values ​​(RW1, RW2) and associated setting values ​​(EWA; EWB, EWx) for the additional heating element (24) and for the temperature flaps (26, 28) are stored in a memory unit (36) of the pilot control unit (34). [5] Method according to one of the preceding claims, characterized by that additional setting values ​​(EWx) are stored based on a learning phase during the operation of the motor vehicle while maintaining previously stored setting values ​​(EWA, EWB). [6] Electrically driven motor vehicle with a refrigeration system (14, 18, 22) and an air conditioning unit (10), wherein the air conditioning unit (10) is designed to be controlled by the method according to one of the preceding claims. [7] Motor vehicle according to claim 6, wherein the pilot control unit (34) is part of a computer unit assigned to the motor vehicle.

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