Valve assembly

Abstract

The invention relates to a valve assembly (1) comprising a valve (2) and a processor unit (3). The valve (2) has a valve housing (4), a valve spool (5) and an actuator (7) with an electrical servomotor (8). The actuator (7) is set up to exert a displacing force (F) on the valve spool (5) by means of its electrical servomotor (8) such that the valve spool (5) is displaced within the valve housing (4) into at least one end position. A current consumption of the electrical servomotor (8) increases when the valve spool (5) has reached the at least one end position. The processor unit (3) is set up to sense a variation over time in the current consumption of the electrical servomotor (8) and to detect that the valve spool (5) is in the at least one end position when the processor unit (3) finds that the sensed variation over time in the current consumption increases at least by a fixed amount.

Description

[0001] Valve arrangement

[0002] The invention relates to a valve arrangement. A further claim is directed to a thermal management system comprising the valve arrangement.

[0003] Electric vehicles require a cooling system to dissipate the power losses of their units (battery, electric motor, reduction gear, bearings, etc.) and electronic components (inverters, DC / DC converters, DC-AC converters, etc.) during operation and when charging the battery. Electric vehicles typically have multiple cooling circuits, some of which can be linked together to form a thermal management system. Typically, a water-glycol mixture circulates in a coolant circuit, dissipating the lost heat to the environment. Another cooling circuit includes a heat pump or air conditioning system for cooling the passenger compartment or supporting heat dissipation from the units. Some systems provide a third cooling circuit for dissipating heat from the transmission's lubrication and cooling oil system.

[0004] Controlling the heat flows requires devices that direct the fluid flows in different directions or assign them to different circuits. Commonly used are solenoid-operated valves in 2 / 3, 2 / 4, or 3 / 4-way designs, which are connected in various combinations to create the intended coolant circuits. Also known are rotary slide valves with stepper motor control, which enable the circuits to be connected. This function can also be implemented with axial slide valves.

[0005] The position of a valve spool of such a valve must be known for the proper functioning of the cooling system. This can be achieved by integrating additional sensors. Alternatively, the valve actuator (e.g., a stepper motor) can already incorporate this sensor technology. Depending on the design or type of sensor, this can ensure a precise determination of the position of the valve spool and thus also a diagnosis of the valve's functionality by detecting the discrete position of the valve spool. However, this requires additional processing and evaluation of the additional signals, as well as complex hardware installation and increased space requirements. Both of these are particularly costly.

[0006] One object of the present invention can be seen in providing a technology that avoids the disadvantages described above and, in particular, enables a particularly simple determination of a valve spool position. This object is achieved by the subject matter of the independent patent claims. Advantageous embodiments are the subject matter of the dependent claims, the following description, and the figures.

[0007] To avoid additional sensors, the invention proposes using data and signals that are already present or available and, in particular, ensuring the necessary diagnostic requirement by means of clever evaluation and assessment. According to one embodiment, a coolant distribution module with axial slide valves with DC servo motors is proposed. Such a coolant distribution module, which is also referred to below as a valve arrangement, enables a simple detection of a valve slide position, a diagnosis of the valve condition and automatic calibration. The valve arrangement according to the invention can be used for a method for calibrating the axial valve slide position by determining an end position of the valve slide without additional sensors. Furthermore, the valve arrangement according to the invention can be used for a method for diagnosing and eliminating piston seizure or stiffness on the piston.

[0008] The present invention is based in particular on the finding that the power of the servomotor is directly proportional to its current consumption. Thus, the servomotor has a relatively constant power requirement when moving the valve spool. This power requirement depends, in particular, only on the resistance of the valve spool or its piston. Thus, the current consumption also remains relatively constant. However, as soon as one of the two end positions is reached, the current consumption of the servomotor increases, so that by evaluating the current curve over time (current consumption gradient), this point can be determined as the end position. The same applies to the opposite direction of movement of the valve spool.

[0009] In this sense, according to a first aspect of the invention, a valve arrangement is proposed that comprises a valve and a processor unit. The valve has a valve housing, a valve spool, and an actuator with an electric servomotor. The actuator is configured to exert a displacement force on the valve spool by means of its electric servomotor, so that the valve spool is displaced within the valve housing into at least one end position. The displacement / positioning of the valve spool can be carried out, for example, by means of a linear actuator with a spindle gear or by means of a linear motor with direct drive of the piston.

[0010] In particular, the valve spool can be moved back and forth in an axial direction within the valve housing by means of the actuator. The axial direction refers to a longitudinal axis of the valve housing and / or the valve spool. A current consumption of the electric actuator motor increases when the valve spool has reached at least one end position. The processor unit is configured to record a temporal profile of the current consumption of the electric actuator motor and to detect that the valve spool is in at least one end position when the processor unit recognizes that the recorded temporal profile of the current consumption increases by at least a specified degree. This degree of increase in current consumption over time can, for example, be stored in a database to which the processor unit can access.

[0011] The valve spool can, in particular, be designed such that in the respective end position, further movement is restricted or requires an increasing displacement force, or a fixed stop prevents further movement and thus a defined end position is determined. In this sense, according to a further embodiment, a stop buffer restricts further displacement of the valve spool or causes an increase (this increase can be progressive or exponential or linear) in the displacement force when the valve spool has reached the at least one end position. Alternatively, a mechanical stop element can prevent further displacement of the valve spool when the valve spool has reached the at least one end position.

[0012] The dimensions of the actuator are selected such that, during the displacement of the valve spool, the actuator's power limit is utilized, in particular, to a maximum of 60%. In this sense, according to a further embodiment, the actuator is dimensioned such that its maximum permissible power is not reached while the actuator is displacing the valve spool to the first end position or the second end position.

[0013] In particular, the actuator is configured to exert the displacement force on the valve spool by means of its electric servomotor, so that the valve spool is displaced within the valve housing selectively into a first end position or into a second end position. When the valve spool is in the first end position, a first end face of the valve spool is located, in particular, in a first end region on a corresponding first end side of the valve housing. When the valve spool is in the second end position, a second end face of the valve spool is located, in particular, in a second end region on a corresponding second end side of the valve housing.

[0014] By comparing the two end positions, simple calibration or adjustment is possible. The running time of the valve spool to move from one end position to the next is relatively constant or can be compared using a characteristic map, whereby the time or duration between the two end positions can be used as a useful basis for function or error diagnosis. Using this characteristic map, it is possible to perform a trend analysis that allows conclusions to be drawn about the position and condition of the valve and thus enables error detection. In this sense, according to a further embodiment, the actuator is designed to exert the displacement force on the valve spool by means of its electric servomotor, so that the valve spool is moved within the valve housing into a first end position and into a second end position.The processor unit is configured to access time information that describes the target time period within which the valve spool is moved by the actuator from the first switching position to the second switching position and vice versa when the valve is functioning properly. Furthermore, the processor unit is configured to determine the position of the valve spool based on the time information. The processor unit can also be configured to obtain the time information from data from a characteristic map.

[0015] In the event of a fault (e.g., stiffness, contamination, or jamming of the valve spool or piston), the running time changes so that, depending on the result (shorter or longer), the cause of the fault can be narrowed down and appropriate remedial measures can be initiated. In this sense, according to a further embodiment, the processor unit is configured to determine, based on the time information, whether the valve is fully functional or malfunctioning. The processor unit compares an actually measured period, within which the recorded temporal profile of the current consumption has increased by at least the specified degree, with the target period.

[0016] If the running time suddenly becomes shorter, it can be assumed that the valve piston is blocked. In this sense, according to a further embodiment, the processor unit is configured to detect that the valve spool is blocked within the valve housing, instead of being in the first end position or the second end position as intended, if the target period is several times longer than the actually measured period.

[0017] A longer running time can be concluded that the piston is stiff, whereby the average power of the actuator will also increase, resulting in higher current consumption of the actuator. In this sense, according to a further embodiment, the processor unit is configured to detect that the valve spool must overcome unintended resistances while being moved from the first end position to the second end position or vice versa if the actually measured period exceeds the target period by a specified limit. This specified limit can, for example, be stored in a database to which the processor unit can access.

[0018] If a malfunction is detected, appropriate countermeasures can be initiated. For example, an attempt can be made to move the valve spool by repeating a previous reverse movement. Alternatively or additionally, the servomotor can also be controlled such that the actuator exerts a shaking motion on the valve spool. In this sense, according to a further embodiment, the processor unit is configured to control the servomotor in such a way that a detected valve malfunction is counteracted.

[0019] If these measures fail to remedy the situation, an error message and possibly a message can be generated in the system. In this sense, according to a further embodiment, the processor unit is configured to generate an error message and transmit it to a higher-level control module (for example, an electronic control unit of the motor vehicle; in English: Electronic Control Unit ECU) if the detected valve malfunction could not be counteracted by controlling the actuator.

[0020] In addition, an attempt can be made to achieve a defined piston position in order to achieve calculable conditions. In this sense, according to a further embodiment, the processor unit is configured to control the servomotor such that the actuator moves the valve spool into a safety position so that the valve is in a calculable state. This safety position can be defined and stored in a database to which the processor unit can access. According to a second aspect of the invention, an energy distribution system or a thermal management system is proposed. The thermal management system comprises at least one valve according to the first aspect of the invention. Furthermore, the thermal management system can comprise at least one coolant pump. Furthermore, at least two connections for line harnesses can be provided.The line bundles are fluidically connected to the components to be supplied with coolant and form a closed coolant circuit, with a return line from the components being fluidically connected to the suction side of the coolant pump(s). At least one coolant pump serves to circulate the coolant within the coolant circuit. At least two coolant pumps can be integrated into the coolant circuit in series. This allows the pressure level within the cooling circuit to be increased. Alternatively, a parallel connection of at least two coolant pumps can be provided. A combination of series and parallel connection is also feasible, depending on the objectives or requirements of the components.

[0021] According to a third aspect of the invention, a method for determining a position of a valve spool is provided. According to the method, a valve arrangement according to the first aspect of the invention or a thermal management system according to the second aspect of the invention is provided. The method further comprises the steps

[0022] - Recording a temporal progression of the current consumption of the electric actuator and

[0023] - Detecting that the valve spool is in the at least one end position when the processor unit detects that the detected temporal profile of the current consumption increases by at least a specified degree.

[0024] The embodiments described in connection with the valve arrangement according to the first aspect of the invention are also analogously applicable to the method according to the third aspect of the invention. Thus, according to one embodiment of the method, time information can be accessed which describes the target period within which the valve spool is moved by the actuator from the first switching position to the second switching position and vice versa when the valve is functioning properly. Furthermore, based on the time information, the position of the valve spool can be determined. The time information can be obtained, in particular, from data from a characteristic map.

[0025] According to a further embodiment, it can be determined based on the time information whether the valve is fully functional or malfunctioning by comparing an actually measured period, within which the detected temporal profile of the current consumption has increased by at least the specified degree, with the target period. Furthermore, it can be detected that the valve spool is blocked within the valve housing instead of being in the first end position or in the second end position if the target period is many times longer than the actually measured period. In the event of a malfunction, the actuator motor can be controlled in such a way that the detected valve malfunction is counteracted. If the detected valve malfunction could not be counteracted by controlling the actuator motor, an error message can be generated and transmitted to a higher-level control module.In addition, the actuator can be controlled in such a way that the actuator moves the valve spool into a safety position so that the valve is in a predictable state.

[0026] In the following, embodiments of the invention are explained in more detail with reference to the schematic drawing, wherein identical or similar elements are provided with the same reference numerals.

[0027] Fig. 1 a is a longitudinal sectional view of an embodiment of a valve arrangement according to the present invention,

[0028] Fig. 1 b is a force-displacement diagram for a valve of the valve arrangement according to Fig. 1a,

[0029] Fig. 1 c shows a current-time diagram for the valve arrangement according to Fig. 1 a, Fig. 2a shows the valve arrangement according to Fig. 1a with a first alternative valve,

[0030] Fig. 2b is a force-displacement diagram for the valve from Fig. 2a,

[0031] Fig. 3a the valve arrangement according to Fig. 1 a with a second alternative valve,

[0032] Fig. 3b is a force-displacement diagram for the valve from Fig. 3a,

[0033] Fig. 4 shows an embodiment of a thermal management system according to the invention with two valve arrangements according to Fig. 1a or Fig. 2a or Fig. 3a and

[0034] Fig. 5 shows a variation of the thermal management system according to Fig. 4.

[0035] Fig. 1 a shows a valve arrangement 1 comprising a valve 2 and a processor unit 3. The valve 2 in turn comprises a valve housing 4, a valve spool 5 with a piston 6 attached thereto, and an actuator 7 with an electric servomotor 8. The actuator 7 exerts a displacement force F on the valve spool 5 by means of its electric servomotor 8. The actuator 7 can, for example, be designed as a linear actuator which is configured to exert the displacement force F on the valve spool 5 either directly or via a spindle gear.

[0036] The displacement force F can cause the valve spool 5 to be displaced back and forth within the valve housing 4. The displacement force F can act in a first axial direction x1 of the valve spool 5, such that the valve spool 5 is displaced into a first end position. The displacement force F can also act in a second axial direction x2 of the valve spool 5, such that the valve spool 5 is displaced into a second end position. When the valve spool 5 is in the first end position, a first end face 9 of the piston 6 of the valve spool 5 is located in a first end region on a corresponding first end face S1 of the valve housing 4. When the valve spool 5 is in the second end position, however, a second end face 9 of the valve spool 5 is located in a second end region on a corresponding second end face S2 of the valve housing 4.

[0037] A first stop buffer 11 is arranged in the first end region on the first end face S1. A second stop buffer 12 is arranged in the second end region on the second end face S2. In the exemplary embodiment shown in Fig. 1a, both stop buffers 11, 12 are formed by a rubber spring with a progressive characteristic curve. As soon as the first end face 9 of the piston 6 has reached the first stop buffer 11 and touches it, the valve spool 5 is in the first end position. Depending on the stiffness of the first stop buffer 11, the valve spool 5 can be displaced a little further in the first axial direction x1 against a restoring force of the first stop buffer 11. However, this requires an increased displacement force F. Analogously, the valve spool 5 is in the second end position as soon as the second end face 10 of the piston 6 has reached the second stop buffer 12 and touches it.Depending on the rigidity of the second stop buffer 12, the valve spool 5 can be displaced a little further in the second axial direction x2 against a restoring force of the second stop buffer 12. However, this requires an increased displacement force F. The two stop buffers 11, 12 thus limit further displacement of the valve spool 5 and thereby cause a progressive increase in the displacement force F.

[0038] In an alternative embodiment, the two stop buffers 11, 12 can be omitted and the valve housing 4 can be constructed correspondingly shorter if necessary. In this case, a first inner end face 15 of the valve housing 4 can form a mechanical stop element which prevents further displacement of the valve spool 5 as soon as the first end face 9 of the piston 6 of the valve spool 5 has reached the first inner end face 15 of the valve housing 4 and touches it. Analogously, a second inner end face 16 of the valve housing 4 can form a mechanical stop element which prevents further displacement of the valve spool 5 as soon as the second end face 10 of the piston 6 of the valve spool 5 has reached the second inner end face 16 of the valve housing 4 and touches it.

[0039] The actuator 8 is dimensioned such that during the above-described displacement of the valve spool 5 into the first or second end position, the performance limit of the actuator 8 is utilized to a maximum of 60%. Fig. 1 b shows a curve of the displacement force F that the actuator 7 must exert on the valve spool 5 in order to move the valve spool 5 along its piston travel s from the first end position to the second end position and vice versa, as well as beyond. The displacement force F is largely constant and only increases exponentially in the region of the two end positions when the piston 6 has reached the first stop buffer 11 or the second stop buffer 12. In order to displace the valve spool 5 as described above by means of the actuator 7, the actuator 8 must be energized. Fig. 1 c shows a diagram in which a graph 14 represents a corresponding temporal current consumption I (t) of the electric actuator 8.The values ​​of the current consumption I (t) increase when the valve spool 5 has reached the first or second end position and is to be moved further beyond it.

[0040] The processor unit 3 can record a time profile 14 of the current consumption I of the electric actuator motor 8. If the processor unit 3 detects that the recorded time profile 14 of the current consumption I increases by at least a specified degree, then it can detect or determine that the valve slide 5 is in one of the two end positions. This degree The increase in current consumption I over time t can be stored, for example, in a database 13, to which the processor unit 3 can access can take hold. The degree of the increase in current consumption I over time t can be illustrated graphically by a gradient of the graph 14. In Fig. 1 c, an increased gradient 18 in the region of the first end position is shown as an example. The value of this gradient corresponds to — . The processor unit 3 accesses time information 17, which can be stored in the database 13, for example in the form of characteristic map data. The time information 17 describes the target period tm within which the valve spool 5 is moved by means of the actuator 7 from the first switching position to the second switching position and vice versa when the valve 2 is functioning correctly. Based on the time information 17, the processor unit 3 can determine the position of the valve spool 5.

[0041] In the event of a fault (e.g. if the piston 6 is stiff, dirty or jammed), the running time changes so that, depending on the result (shorter or longer), the cause of the fault can be narrowed down and appropriate remedial measures can be initiated. The processor unit 3 can compare an actually measured period tmi, within which the recorded temporal profile of the current consumption l(t) has increased by at least the specified degree, with the target period tm. The actually measured period tmi can be contained in the time information 17. The actually measured period tmi can also be determined by the processor unit 3 itself. Based on the comparison between the actually measured period tmi and the target period tm, the processor unit 3 can determine whether the valve 2 is fully functional or has a malfunction.

[0042] If the target period tm is many times longer than the actually measured period tmi, then the processor unit 3 detects that the valve spool 5 is blocked within the valve housing 4 instead of being in the first end position or in the second end position. If the actually measured period tmi exceeds the target period tm by a specified limit value tnm, then the processor unit 3 detects that the valve spool 4 has to overcome unforeseen resistances, i.e. is stiff, while being moved from the first end position to the second end position or vice versa. This specified limit value tiim can, for example, be stored in the database 13, which the processor unit 3 can access. If the processor unit 3 detects a malfunction, the processor unit 3 can initiate suitable countermeasures, e.g. a repeat with a previous backward movement, shaking or the like.If these measures do not remedy the situation, an error entry and possibly a message can be generated in the system. To this end, the processor unit 3 can generate an error message and transmit it to a higher-level control module (for example, to an electronic control unit 19 of the motor vehicle; in English: Electronic Control Unit ECU). In addition, an attempt can be made to achieve a defined piston position in order to achieve calculable conditions. To this end, the processor unit 3 can control the servo motor 8 such that the actuator 7 moves the valve spool 5 into a safety position Ssavety, so that the valve 2 is in a calculable state. This safety position Ssavety can be defined and stored in the database 13.

[0043] Fig. 2a shows the valve arrangement according to Fig. 1a, wherein the valve 2 has been replaced by an alternative valve 2'. The valve 2' according to Fig. 2a is basically constructed in the same way as the valve 2 according to Fig. 1a. However, instead of the rubber springs 11, 12, the valve 2' according to Fig. 2a has two air springs 11', 12' with a progressive characteristic curve as stop buffers. Fig. 2b shows a curve of the displacement force F that the actuator 7 must exert on the valve spool 5 in order to move the valve spool 5 along its piston travel s from the first end position to the second end position and vice versa. The displacement force F is largely constant and only increases exponentially in the region of the two end positions when the piston 6 has reached the first air spring 11' or the second air spring 12'. Compared to the rubber springs 11, 12 according to Fig. 1a, the progressive increase of the displacement force F is lower in the air springs 11', 12' according to Fig. 2a.

[0044] Fig. 3a shows the valve arrangement according to Fig. 1a, wherein the valve 2 has been replaced by another alternative valve 2". The valve 2" according to Fig. 3a is basically constructed in the same way as the valve 2 according to Fig. 1a. However, instead of the rubber springs 11, 12, the valve 2" according to Fig. 3a has two mechanical springs 11", 12" with a linear characteristic curve as stop buffers. Fig. 3b shows a curve of the displacement force F that the actuator 7 must exert on the valve spool 5 in order to move the valve spool 5 along its piston travel s from the first end position to the second end position and vice versa. The displacement force F is largely constant and only increases linearly in the region of the two end positions when the piston 6 has reached the first mechanical spring 11" or the second mechanical spring 12".

[0045] Fig. 4 shows a thermal management system 20 with two valve assemblies 1, as shown, for example, in Fig. 1a. In the exemplary embodiment shown, the thermal management system 20 further comprises a coolant pump 21, a heat exchanger 22, a cooler or radiator 23 and components 24 to be cooled. The protruding elements 1 and 21 to 25 of the thermal management system 20 are fluidly connected to one another in a closed coolant circuit 25. The coolant pump 21 ensures that a coolant circulates within the coolant circuit 25. The coolant absorbs heat from the elements 24 to be cooled and can be recooled by the heat exchanger 23 and / or the radiator 23. By means of the two valve assemblies 1, fluid flows can be divided or directed between the elements 24 to be cooled, the coolant pump 21, the heat exchanger 22 and the radiator 23.

[0046] Fig. 5 shows a variation 20' of the thermal management system 20 shown in Fig. 4. The thermal management system 20' shown in Fig. 4 comprises a separate, independent battery cooling circuit 26 with an optional BMS cooling system 27 (BMS stands for battery management system) and an integrated electronic component 28 (e.g., an on-board charger OBC) with a pump and heat exchanger. Fig. 4 shows two different variants of the battery cooling circuit 26.

[0047] Reference symbol

[0048] — Degree of increase in current consumption over time

[0049] I Current consumption s Piston travel

[0050] Ssavety safety position

[0051] 51 first front side

[0052] 52 second end face tlim limit value tm target period tmi actually measured period z time x1 first axial direction x2 second axial direction

[0053] 1 valve arrangement

[0054] 2 valve

[0055] 2' alternative valve

[0056] 2" additional alternative valve

[0057] 3 Processor unit

[0058] 4 valve housings

[0059] 5 valve slides

[0060] 6 pistons

[0061] 7 Actuator

[0062] 8 electric actuator

[0063] 9 first frontal surface

[0064] 10 second front face

[0065] 11 first rubber spring

[0066] 12 second rubber spring

[0067] 11 ' first air spring

[0068] 12' second air spring

[0069] 11 “ first mechanical spring

[0070] 12“ second mechanical spring database temporal course of current consumption first mechanical stop element second mechanical stop element time information

[0071] Slope electronic control unit

[0072] Thermal management system ' Thermal management system coolant pump

[0073] heat exchanger

[0074] Radiator components to be cooled Coolant circuit separate battery cooling circuit

[0075] BMS cooling integrated electronic component

Claims

Patent claims 1. Valve arrangement (1) comprising a valve (2) and a processor unit (3), wherein - the valve (2) comprises a valve housing (4), a valve slide (5) and an actuator (7) with an electric servomotor (8), - the actuator (7) is designed to exert a displacement force (F) on the valve slide (5) by means of its electric servomotor (8), so that the valve slide (5) is displaced within the valve housing (4) into at least one end position, - a current consumption (I) of the electric servomotor (8) increases when the valve slide (5) has reached at least one end position, and - the processor unit (3) is configured to record a time profile (14) of the current consumption (I) of the electric servomotor (8) and to detect that the valve slide (5) is in the at least one end position when the processor unit (3) detects that the recorded time profile (14) of the current consumption (I) increases by at least a predetermined degree (18).

2. Valve arrangement (1) according to claim 1, wherein - a stop buffer (11, 12) restricts further displacement of the valve slide (5) or causes an increase in the displacement force (F), or - a mechanical stop element (15, 16) prevents further displacement of the valve slide (5) when the valve slide (5) has reached at least one end position.

3. Valve arrangement (1) according to one of the preceding claims, wherein the servo motor (8) is dimensioned such that its maximum permissible power is not reached while the actuator (7) moves the valve slide (5) into the first end position or into the second end position.

4. Valve arrangement (1) according to one of the preceding claims, wherein - the actuator (7) is designed to exert the displacement force (F) on the valve slide (5) by means of its electric servomotor (8), so that the valve slide (5) is displaced within the valve housing (4) selectively into a first end position or into a second end position, and - the processor unit (3) is designed to - to access time information (17) which describes within which target period (tm) the valve slide (5) is moved by means of the actuator (7) from the first switching position to the second switching position and vice versa when the valve (2) is functioning properly, and - to determine the position of the valve spool (5) based on the time information (17).

5. Valve arrangement (1) according to claim 4, wherein the processor unit (3) is configured to determine, based on the time information, whether the valve (2) is fully functional or malfunctioning, by the processor unit (3) comparing an actually measured period (tmi), within which the detected temporal profile of the current consumption (l(t)) has increased by at least the specified degree (18), with the target period (tm).

6. Valve arrangement (1) according to claim 5, wherein the processor unit (3) is configured to detect that the valve spool (5) is blocked within the valve housing (4) instead of being in the first end position or in the second end position when the target period (tm) is many times longer than the actually measured period (tm).

7. Valve arrangement (1) according to claim 5 or 6, wherein the processor unit (3) is arranged to detect that the valve slide (4) must overcome unintended resistances while being displaced from the first end position to the second end position or vice versa, if the actually measured period (tmi) exceeds the target period (tm) by a predetermined limit value (tiim).

8. Valve arrangement (1) according to one of claims 5 to 7, wherein the processor unit (3) is designed to control the servo motor (8) in such a way that a detected malfunction of the valve (2) is counteracted.

9. Valve arrangement (1) according to claim 8, wherein the processor unit (3) is configured to generate an error message and to transmit it to a higher-level control module (19) if the detected malfunction of the valve (2) could not be counteracted by controlling the servo motor (7).

10. Valve arrangement (1) according to claim 8 or 9, wherein the processor unit (3) is configured to control the servo motor (8) such that the actuator (7) moves the valve slide (5) into a safety position (Ssavety), so that the valve (2) is in a predictable state.

11. Thermal management system (20; 21') comprising at least one valve arrangement (1) according to one of the preceding claims.

12. Method for determining a position of a valve spool (5), the method comprising the steps: - Providing a valve arrangement (1) according to one of claims 1 to 10 or a thermal management system (20; 20') according to claim 11, - detecting a time profile (14) of the current consumption (I) of the electric servo motor (8) and - Detecting that the valve slide (5) is in the at least one end position when the processor unit (3) detects that the detected temporal profile (14) of the current consumption (I) increases by at least a predetermined degree (18).

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