Method for determining a lower current threshold of a strip conductor of a solenoid coil of a solenoid valve for a valve unit which is fluidically connected to a pressurized fluid reservoir, device, and vehicle
Patent Information
- Application Number
- EP2023700686
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-03-03
- Filing Date
- 2023-01-10
- Publication Date
- 2025-01-08
- Estimated Expiration
- 2043-01-10
AI Technical Summary
Current valve units with solenoid valves in hydrogen storage systems for vehicles consume excessive electrical energy due to continuous current flow required to keep the magnetic valve open, and technical tolerances lead to varying current needs, resulting in inefficient power usage.
A method to determine the lower current threshold value of a solenoid coil's current band by actively energizing and de-energizing the coil based on detected current thresholds, using a pulsating current to maintain the armature in a fully open position, thereby minimizing power consumption.
This method allows for the efficient determination and maintenance of the lower current threshold value, reducing power consumption of solenoid valves, especially in hydrogen fuel cell vehicles, by ensuring only the necessary minimum current is used to keep the valve open, thereby minimizing energy expenditure.
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] title
[0003] Method for determining a lower current threshold value of a current band of a solenoid coil of an il for a valve unit communicating with a fluid. as well as
[0004] State of the art
[0005] In order to store hydrogen for operation in a vehicle, several compressed gas tanks can be installed in the vehicle. These compressed gas tanks are each equipped with a multifunctional valve unit, the main function of which is to close the respective compressed gas tank when the vehicle is not in use. For this purpose, the valve units are usually equipped with a self-closing solenoid valve. If no current flows through a solenoid coil of the solenoid valve, the solenoid valve closes automatically, e.g. due to a spring force. This behavior is necessary for safety reasons, but has the disadvantage that current must constantly flow through the solenoid coil during ferry operation to keep the solenoid valve open. This permanently consumes a small amount of electrical energy.
[0006] It's a constant effort to keep the actual electrical power required by a component as low as possible. Furthermore, valve units and solenoid valves within valve units are subject to technical tolerances, so the current that must flow through the solenoid coil to keep the solenoid valve open can vary.
[0007] Disclosure of the invention The present invention shows a method according to the features of claim 1, a device according to the features of claim 10, and a vehicle according to the features of claim 11.
[0008] Further features and details of the invention emerge from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the device according to the invention and the vehicle according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.
[0009] According to a first aspect, the present invention shows a method for determining (at least) a lower current threshold value of a current band of a magnetic coil of a magnetic valve for a valve unit fluidly communicating with a pressure fluid reservoir, in particular of a vehicle, wherein when an electric current flows through the magnetic coil at the level of the current band, an armature of the magnetic valve that is movable by the magnetic coil can be held in a fully open position, wherein the movable armature comprises at least one movement state when transferred between a closed position of the armature and the fully open position of the armature and a rest state in the fully open position.The method comprises, as one step, actively energizing the solenoid coil of the solenoid valve, wherein the active energization of the solenoid coil of the solenoid valve is switched off upon detection of an electrical current flowing through the solenoid coil at the level of an upper current threshold of the current band. Furthermore, the method comprises, as one step, actively energizing the solenoid coil of the solenoid valve again by the electrical energy source upon detection, in particular upon detection of an undershoot, of an electrical current flowing through the solenoid coil at the level of a definable, variable current threshold that is lower than the upper current threshold. Furthermore, a step of the method according to the invention is changing the level of the definable, variable current threshold or changing the level of the definable, variable current threshold and (additionally) changing the level of the upper current threshold.Furthermore, a further step of the method is a continuous measurement of a measurement signal, in particular a continuous measurement of a measurement signal and an evaluation of the measurement signal, to detect a change in the state of the armature of the solenoid valve between the at least one movement state and the rest state of the armature. Furthermore, the method comprises, as a step, determining (at least) the lower current threshold of the current band based on the definable, variable current threshold when the change in the state of the armature of the solenoid valve is detected, in particular was detected (in advance) due to the change in the definable, variable current threshold.
[0010] The process steps described above and below can, where technically feasible, be carried out individually, together, simply, multiple times, in parallel and / or consecutively in any order.
[0011] In particular, it is also conceivable that the method according to the invention and / or the device according to the invention is used to determine (at least) a lower current threshold value of a current band of a magnetic coil of a magnetic valve for a valve unit of a stationary energy unit, for example a power generator or a fuel cell heater, which valve unit is in fluid communication with a pressure fluid reservoir.
[0012] The valve unit is in particular fluidically connectable or connected to at least one pressure fluid reservoir, for example of the vehicle or a stationary energy unit.
[0013] The fully open position of the armature is understood in particular to be a position of the armature in which the flow of a fluid through the valve unit, in particular through a fluid channel of the valve unit, is maximum. In the fully open position, the armature of the solenoid valve is in the rest state, i.e. at rest or essentially at rest. The armature of the solenoid valve can also be understood as a magnet armature. In particular, the state of movement of the armature is understood to be a state of the armature in which the armature moves, in particular along an axis of the armature, e.g. from the closed position to the fully open position. In other words, the armature is not at rest in the state of movement. The closed position of the armature is understood in particular to be a position of the armature in which the flow of a fluid through the valve unit, in particular through a fluid channel of the valve unit, is not maximum, e.g. minimal.
[0014] If a change in the state of the solenoid valve's armature, which occurred due to a change in the definable, variable current threshold, has been detected, the lower current threshold is determined, in particular based on this definable, variable current threshold, in such a way that the movable armature is held in the fully open position at the resulting lower current threshold. The term "based" in "the lower current threshold is determined, in particular, based on this definable, variable current threshold" is intended to express, in particular, that this definable, variable current threshold is, for example, multiplied by a factor, or an offset is added, or, for example, the previous definable, variable current threshold is used as the lower current threshold.
[0015] The active energization of the solenoid coil of the solenoid valve, the deactivation of the active energization of the solenoid coil upon detection or recording of the upper current threshold of the current band, and the renewed, active energization of the solenoid coil upon detection or recording of the definable, variable current threshold are particularly repetitive processes of the method according to the invention. In other words, the solenoid coil of the solenoid valve can be actively energized in a pulsating manner. This can cause a dynamic change in the inductance of the solenoid coil when the armature starts moving. The electric current flowing through the solenoid coil during pulsating, active energization can have a periodic waveform, in particular a sawtooth-like or essentially sawtooth-like current waveform or a sinusoidal current waveform.The pulsating, active energization of the solenoid coil of the solenoid valve is carried out in particular to determine the lower current threshold using the method according to the invention (calibration mode). However, the solenoid coil of the solenoid valve can also be pulsatingly, actively energized, particularly during normal operation of the solenoid valve, to (permanently) hold the movable armature of the solenoid valve in the fully open position. Advantageously, the pulsating energization of the solenoid coil of the solenoid valve makes it particularly easy to achieve an average permissible current for the solenoid coil. The electrical energy for the active energization can be provided by an electrochemical storage device, e.g., a vehicle battery.
[0016] The active energization of the solenoid coil of the solenoid valve can be switched on and off by controlling an electrical switch, e.g. a field-effect transistor.
[0017] With the method according to the invention, at least the respective lower current threshold value of a current band required to hold a respective solenoid valve of a plurality of solenoid valves in the fully open position for keeping the respective solenoid valve open can be determined particularly easily and / or quickly and / or reliably. With the respective determined lower current threshold value, the current consumption of a respective solenoid valve of the plurality of solenoid valves, e.g., of solenoid valves on hydrogen cylinders of a fuel cell vehicle, can be particularly advantageously low, preferably minimized. In particular, each solenoid valve is energized only with the necessary lower minimum electrical current (or lower minimum current intensity) of the current band.Preferably, the lower current threshold of the current band for a solenoid coil is a lower minimum current threshold of the current band or a substantially lower minimum current threshold of the current band at which the armature of the solenoid valve can (just) be maintained or held in the fully open position.
[0018] With the method according to the invention, in addition to the lower current threshold, the upper current threshold can also be determined, in particular as a function of the determined lower current threshold. Thus, the current consumption of a respective solenoid valve of the plurality of solenoid valves, e.g., solenoid valves on hydrogen cylinders of a fuel cell vehicle, for keeping the respective armatures (fully) open can be particularly low, especially when the solenoid coils of the solenoid valves are actively energized in a pulsating manner during normal operation of the solenoid valves.
[0019] The change in the state of the armature between the moving state and the rest state can also be understood as a state transition. It can be advantageous if, in a method according to the invention, the change in the state of the armature is a change of the armature from the rest state to the moving state or a change of the armature from the moving state to the rest state.
[0020] In particular, the definable, variable current threshold can be understood as a temporary lower current threshold of the current band in order to be able to determine the lower current threshold of the current band for normal operation of the solenoid valve.
[0021] In addition to switching off the active current supply to the solenoid coil of the solenoid valve when detecting the electrical current flowing through the solenoid coil at the level of the upper current threshold of the
[0022] A freewheeling circuit connected in parallel to the solenoid coil can be switched to electrically conductive ("closed") at the same time or essentially at the same time, so that the electrical current flowing through the solenoid coil of the solenoid valve can be dissipated particularly advantageously due to the ohmic resistance of the solenoid coil. The freewheeling circuit has, for example, a "freewheeling transistor" for electrically conductive switching of the freewheeling circuit. In particular, the freewheeling circuit is switched to electrically non-conductive ("open") during the active energization of the solenoid coil of the solenoid valve. A device according to the invention can have such a freewheeling circuit.
[0023] The time interval during which the solenoid valve's solenoid coil is actively energized is also referred to as the rise interval. The time interval from the active energization of the solenoid coil being switched off when the upper current threshold is detected until the solenoid coil is actively energized again when the definable, adjustable current threshold or the lower current threshold is detected is also referred to as the fall interval. The fall interval can also be referred to as the freewheeling interval if a freewheeling circuit is used.
[0024] Over the course of a solenoid valve's lifetime, its properties can change, necessitating the lower current threshold and / or upper current threshold used to operate the solenoid valve or the solenoid coil of the solenoid valve, i.e., the current band, to be adjusted so that the solenoid valve or a valve unit with such a solenoid valve can operate particularly advantageously and energy consumption is particularly low. Advantageously, a device according to the invention can be configured to determine, and if necessary, adjust, a particularly advantageous lower current threshold and / or upper current threshold at regular intervals. In other words, self-calibration can take place.
[0025] The method according to the invention advantageously takes advantage of the fact that a change in the inductance of the magnetic coil occurs when the state of the armature changes between the moving state and the rest state, since the inductance of the magnetic coil depends, among other things, on the distance between the armature and the magnetic coil. A movement of the armature can thus itself cause a change in the current profile of the electrical current flowing through the magnetic coil compared to the resting armature. In particular, the change in the state of the armature of the solenoid valve between the at least one moving state and the resting state of the armature can be recognized or detected based on the change in the current profile. The change in the current profile can be used as an indicator of the movement of the armature.
[0026] It can be advantageous if, in a method according to the invention, the level of the definable, variable current threshold is temporarily increased stepwise and / or temporarily decreased stepwise to change the level of the definable, variable current threshold for determining the lower current threshold. Thus, a change in the state of the armature of the solenoid valve between the at least one movement state and the rest state of the armature can be triggered in a particularly simple manner in order to detect movement of the armature. In addition to at least temporarily increasing the level of the definable, variable current threshold, the upper current threshold can also be increased stepwise at the same time to determine the lower current threshold.In addition to at least temporarily gradually reducing the level of the definable, variable current threshold, the upper current threshold can also be gradually reduced at the same time to determine the lower current threshold. In other words, in particular, a shift in the current band can occur to determine the lower current threshold. Thus, the lower current threshold can be determined particularly quickly.
[0027] Advantageously, in a method according to the invention for detecting the change in state of the armature of the solenoid valve between the at least one moving state and the rest state of the armature, the electrical current flowing through the solenoid coil can be considered as the measurement signal. In other words, the current profile of the electrical current flowing through the solenoid coil can be considered. Thus, when a change in the current profile of the electrical current flowing through the solenoid coil is detected, it is particularly easy to infer a change in the state of the armature of the solenoid valve. The electrical current flowing through the solenoid coil can be understood in particular as the electrical current flowing directly through the solenoid coil. However, it is also conceivable that a current dependent on the electrical current flowing through the solenoid coil is considered as the measurement signal.
[0028] Advantageously, in a method according to the invention for detecting the change in state of the armature, a time constant of the current flowing through the solenoid coil of the solenoid valve can be considered. The decay of the electrical current flowing through the solenoid coil after the electrical current flowing through the solenoid coil is switched off (upon detection of the upper current threshold) follows an exponential curve. The time constant for the exponential curve can be determined from the ratio of the ohmic resistance, in particular the ohmic resistance of the solenoid coil, and the inductance of the solenoid coil of the solenoid valve. If the inductance decreases, e.g., because the armature releases from the stop of the valve unit, the time constant of the exponential decay also decreases. This time constant can be determined, for example, using a suitable filter routine, e.g., using a Taylor series.Thus, a change in the state of the armature between the rest state and the moving state can lead to a noticeable change in the time constant.
[0029] Particularly advantageously, in a method according to the invention for detecting the change in state of the armature, a current frequency of the current flowing through the solenoid coil of the solenoid valve can be considered. For example, the time that elapses between the active energization of the solenoid coil of the solenoid valve by the electrical energy source upon detection of an electrical current flowing through the solenoid coil at a level of a definable, variable current threshold and a renewed, active energization upon detection of an electrical current flowing through the solenoid coil at a level of a definable, variable current threshold can be determined. In other words, the period duration can be determined and considered, in particular the period duration of a sawtooth-like or substantially sawtooth-like current waveform of the electrical current flowing through the solenoid coil.For example, if the time constant of the exponential curve of the electric current flowing through the solenoid coil decreases, this leads to a shortening of the decay interval, especially the freewheeling interval. Thus, a change in the state of the armature between the rest state and the moving state can advantageously lead to a noticeable change in the current frequency.
[0030] According to a further preferred embodiment, a method according to the invention for detecting the change in state of the armature can consider a frequency spectrum of the current flowing through the solenoid coil of the solenoid valve. For example, the current profile of the electric current flowing through the solenoid coil will exhibit a strictly exponential behavior when the armature is at rest, whereas a movement of the armature will lead to a deviation from the exponential behavior. Thus, a change in the state of the armature between the rest state and the moving state can advantageously lead to a detectable change in the frequency spectrum of the current profile.
[0031] Advantageously, in a method according to the invention, the upper current threshold of the current band can be adjusted to the specific lower current threshold of the current band of the solenoid valve. Thus, the energy consumption of a solenoid coil that is actively energized in a pulsating manner during normal operation of the solenoid valve can be particularly low. For example, the upper current threshold can be determined in such a way that a desired, average, permissible current value for the solenoid coil is obtained.
[0032] Particularly advantageously, in a method according to the invention for detecting the change in state of the armature of the solenoid valve, a value based on the measurement signal can be compared with a limit value. The limit value can also be understood as a threshold value.
[0033] According to a further preferred embodiment, a classification method can be applied in a method according to the invention for detecting the change in state of the armature of the solenoid valve. The classification method can be understood, in particular, as machine learning. Training data can be collected for this purpose. In particular, a statistical model is constructed using an algorithm based on the training data. This allows patterns and regularities in the training data to be recognized, and even unknown data to be evaluated.
[0034] According to a second aspect, the present invention provides a device for determining (at least) a lower current threshold of a current band of a solenoid coil of a solenoid valve for a valve unit fluidly communicating with a pressurized fluid reservoir, in particular of a vehicle. The device has an electrical energy source for providing electrical energy for actively energizing the solenoid coil of the solenoid valve. Furthermore, the device comprises a sensor for detecting an electrical current flowing through a solenoid coil of a solenoid valve. Furthermore, the device comprises a control unit for switching off the electrical current flowing through the solenoid coil of the solenoid valve when an upper current threshold of a current band of the solenoid valve is exceeded, and for actively energizing the solenoid coil of the solenoid valve when a definable, variable current threshold is undershot.The device further comprises a current variation unit for varying the level of the definable, variable current threshold, as well as a measuring unit for measuring a measurement signal to detect a change in the state of the armature of the solenoid valve between at least one moving state and a resting state of the armature. Furthermore, the device has a determination unit for determining (at least) the lower current threshold of the current band based on the definable, variable current threshold when the change in the state of the armature of the solenoid valve is detected due to the change in the definable, variable current threshold. Furthermore, the device is designed to carry out a method according to the invention for determining at least the lower current threshold of the current band for the solenoid coil of the solenoid valve of the valve unit of the pressure fluid reservoir, in particular of the vehicle.
[0035] The valve unit, in particular, has a housing for accommodating the solenoid valve. Furthermore, the valve unit, in particular, has a fluid inlet and a fluid outlet, wherein the fluid inlet is fluidically connectable to the fluid outlet by means of the solenoid valve via a fluid channel. Furthermore, the solenoid valve is, in particular, self-closing, i.e., when no current flows through a solenoid coil of the solenoid valve, the solenoid valve closes automatically, e.g., due to a spring force.
[0036] The electrical energy source is in particular a battery, e.g. a vehicle battery.
[0037] The sensor for detecting the electrical current flowing through the solenoid coil of the solenoid valve can, for example, be a current sensor.
[0038] The control unit is particularly designed to switch the active energization of the electrical current flowing through the solenoid coil of the solenoid valve on and / or off. Furthermore, the control unit can additionally be designed to switch a freewheeling circuit to electrically conductive and / or electrically non-conductive.
[0039] Furthermore, the device can have a memory, in particular a non-volatile memory, for storing lower current threshold values and / or for storing upper current threshold values and / or for storing (the) definable, variable current threshold value(s).
[0040] In particular, the device according to the invention is used to determine the lower current threshold value and / or the upper current threshold value of the current band of the solenoid coil of the solenoid valve for at least one valve unit fluidly communicating with a pressure fluid reservoir, for example a high-pressure hydrogen tank.
[0041] The device according to the second aspect of the invention thus has the same advantages as those already described for the method according to the first aspect of the invention.
[0042] According to a third aspect, the present invention provides a vehicle, wherein the vehicle has at least one pressure fluid reservoir with a valve unit having a solenoid valve for controlling a flow of a pressure fluid storable in the pressure fluid reservoir, in particular a plurality of pressure fluid reservoirs, each with a valve unit having a solenoid valve for controlling a flow of a pressure fluid storable in a respective pressure fluid reservoir of the plurality of pressure fluid reservoirs. Furthermore, the vehicle comprises a device designed according to the invention, wherein the device is further designed to determine at least the lower current threshold value for the solenoid valve of the valve unit for the at least one pressure fluid reservoir.In particular, when there are multiple pressure fluid reservoirs, the device according to the invention is designed to determine (at least) the lower current threshold value for the solenoid valve of the respective valve unit for at least two of the plurality of pressure fluid reservoirs. The vehicle can also be understood as a stationary energy unit.
[0043] The storable pressurized fluid can be, for example, gaseous hydrogen. In particular, the pressurized fluid is stored under high pressure in the pressurized fluid reservoir. Furthermore, the valve unit is arranged, in particular, directly on the pressurized fluid reservoir, for example, at a bottleneck of the pressurized fluid reservoir. The valve unit can also be used as a system isolation valve unit or as a valve unit for a fuel cell system.
[0044] The vehicle according to the third aspect of the invention thus has the same advantages as have already been described for the method according to the first aspect of the invention or the device according to the second aspect of the invention.
[0045] Further measures improving the invention will become apparent from the following description of some exemplary embodiments of the invention, which are schematically illustrated in the figures. All features and / or advantages apparent from the claims, the description, or the drawings, including design details, spatial arrangements, and method steps, may be essential to the invention both individually and in various combinations. It should be noted that the figures are merely descriptive and are not intended to limit the invention in any way.
[0046] They show schematically:
[0047] Fig. 1 is a flow chart,
[0048] Fig. 2 a device,
[0049] Fig. 3 a sawtooth current profile,
[0050] Fig. 4 shows a current profile through a magnetic coil before, during and after determining the lower current threshold, and Fig. 5 shows a vehicle.
[0051] In the following figures, identical reference numerals are used for the same technical features, even in different embodiments.
[0052] Figure 1 schematically discloses a flow diagram of a method for determining a lower current threshold value US or a lower current threshold value US and an upper current threshold value OS of a current band B (see, for example, Figure 3) of a magnetic coil 2 of a magnetic valve for a valve unit 100, for example of a vehicle 200, which is in fluid communication with a pressure fluid reservoir 21 Oa, 21 Ob (see, for example, Figure 4), wherein when an electric current flows through the magnetic coil 2 at the level of the current band B, an armature of the magnetic valve which is movable by the magnetic coil 2 can be held or is held in a fully open position, wherein the movable armature comprises at least one movement state when transferred between a closed position of the armature and the fully open position of the armature and a rest state in the fully open position.The method for determining the lower current threshold value US or the lower current threshold value US and the upper current threshold value OS of the current band B further comprises the steps, in particular the steps of repeating, of actively energizing the solenoid coil 2 of the solenoid valve, wherein the active energization of the solenoid coil 2 of the solenoid valve is switched off upon detection of an electrical current flowing through the solenoid coil 2 at the level of an upper current threshold value OS of the current band B, and a renewed, active energization of the solenoid coil 2 of the solenoid valve by the electrical energy source upon detection of an electrical current flowing through the solenoid coil 2 at the level of a definable, variable current threshold value which is lower than the upper current threshold value OS. Furthermore, a measurement signal, e.g.the electrical current flowing through the magnetic coil 2, in order to detect a change in the state of the armature of the magnetic valve between the at least one moving state and the rest state of the armature, is continuously measured for the time during which the lower current threshold value US is determined or for the time during which the lower current threshold value US and the upper current threshold value OS are determined 20. In this example, it is assumed that the movable armature of the magnetic valve is initially (at start), i.e. for the current band B resulting from the upper current threshold value OS and the current, definable, variable (start) current threshold value, held in a fully open position. As shown in the flow diagram, in order to determine the lower current threshold value US orFor determining the lower current threshold US and the upper current threshold OS, the level of the definable, variable current threshold is now reduced 10 or lowered by one (current) step so frequently, in particular repeatedly, until the change in state of the armature of the solenoid valve, here in this example a change in state of the armature from the rest state to the moving state, is (positively) detected 30 due to the change in the definable, variable current threshold. However, it is also conceivable that the upper current threshold is also successively changed, in particular reduced or increased.If the change in state of the armature of the solenoid valve has been detected due to the change in the definable, variable current threshold, the lower current threshold US of the current band B is determined 40 based on the definable, variable current threshold, wherein the upper current threshold OS can also be determined or adjusted. In particular, the upper current threshold OS is adjusted to the determined lower current threshold US of the current band B of the solenoid valve. For example, the previous, definable, variable current threshold can be determined 40 as the lower current threshold US of the current band B. Furthermore, in the method according to the invention, the determined lower current threshold US and / or the determined upper current threshold OS are stored in a memory 50 in one step.a time constant and / or a frequency spectrum and / or a current frequency of the current flowing through the solenoid coil of the solenoid valve can be considered. In addition, in an optional step, upon detection 60 of reaching a definable minimum threshold, e.g., 0 amperes, for the definable, variable current threshold, the determination of the lower current threshold US or the determination of the lower current threshold US and the upper current threshold OS can be aborted 70 and an error memory entry can be made 80.
[0053] Figure 2 discloses a device 220 for determining at least one lower current threshold value US or a lower current threshold value US and an upper current threshold value OS of a current band B of a solenoid coil 2 of a solenoid valve for a valve unit 100, for example of a vehicle 200, fluidly communicating with a pressurized fluid reservoir 210a, 210b (see, for example, Figure 4). The device 220 has an electrical energy source 222, for example 12 volt vehicle voltage, for providing electrical energy for actively energizing the solenoid coil 2 of the solenoid valve. The solenoid coil 2 is represented in Figure 2 by an ohmic resistor and an (electrical) coil. Furthermore, the device 220 comprises an ammeter as a sensor 224 for detecting an electrical current flowing through a solenoid coil 2 of a solenoid valve.The device 220 further comprises a control unit 226 for switching off the electrical current flowing through the solenoid coil 2 of the solenoid valve when an upper current threshold OS of a current band B of the solenoid valve is exceeded, and for actively energizing the solenoid coil (2) of the solenoid valve when a definable, variable current threshold is undershot. For example, the control unit 226 controls a field-effect transistor 241 to switch off or on (actively energize) the electrical current flowing through the solenoid coil 2 of the solenoid valve. In addition, a "freewheeling transistor" 242 connected in parallel to the solenoid coil 2 can be switched on, for example by the control unit 226, for the time during which the electrical current flowing through the solenoid coil 2 of the solenoid valve is switched off, so that the electrical current flowing through the solenoid coil 2 of the solenoid valve is particularly advantageously reduced due to the ohmic resistance.The device 220 further comprises a current variation unit 228 for varying at least the level of the definable, variable current threshold, as well as a measuring unit 230 for measuring and evaluating a measurement signal obtained by the sensor 224 to detect a change in the state of the armature of the solenoid valve between at least one moving state and a resting state of the armature. To detect the change in the state of the armature of the solenoid valve, for example, a value based on the measurement signal can be compared with a limit value. To detect the change in the state of the armature of the solenoid valve, the application of a classification method (machine learning; e.g., neural network) is possible as an alternative or in addition to the comparison with a limit value.In addition, the device 220 comprises a determination unit 232 for determining at least the lower current threshold US of the current band B based on the definable, variable current threshold, wherein the device 220 is designed to carry out a method according to the invention for determining at least the lower current threshold US of the current band B for the magnetic coil 2 of the solenoid valve. In particular, the sensor 224 and / or the current variation unit 228 and / or the measuring unit 230 and / or the determination unit 232 can also be part of the control unit 226. Furthermore, the device 220 can have a memory, in particular a non-volatile memory, for storing lower current thresholds US and / or for storing upper current thresholds OS and / or for storing the definable, variable current threshold(s).
[0054] Figure 3 discloses a sawtooth-like current profile of an electric current i flowing through a solenoid coil 2 of a solenoid valve. m over time t. When the electric current i flows m At the level of a current band B defined by an upper current threshold value OS and a lower threshold value US through the solenoid coil 2, an armature of the solenoid valve that can be moved by the solenoid coil 2 can be held in the fully open position by the pulsating current supply to the solenoid coil of the solenoid valve, wherein at the same time an average current permissible for the solenoid coil can be realized in a simple manner without damaging the solenoid coil.
[0055] Figure 4 discloses a time profile of a (sawtooth-like) electric current i flowing through a magnetic coil 2 mbefore (see section (1)), during (see section (2)) and after (see section (3)) the determination of an (adjusted) lower current threshold US by means of a method according to the invention or a device 220 according to the invention. The current intensity i m , mindenotes a lower minimum current threshold value of the current band B of the solenoid coil 2 of the solenoid valve at which the armature of the solenoid valve can (just) be maintained or held in the fully open position. Over the course of a solenoid valve's lifetime, particularly at the beginning of its lifetime, the properties of the solenoid valve can change, so that the lower current threshold value US and / or the upper current threshold value OS used for the operation of the solenoid valve or solenoid coil 2, i.e., the current band B, must be adjusted so that the solenoid valve or a valve unit 100 with such a solenoid valve can operate particularly advantageously and the energy consumption is particularly low. In section (1) of the current curve shown in Figure 4, the lower current threshold value US of the current band B of the solenoid coil 2 of the solenoid valve is higher than the lower minimum current threshold value i m , minthe solenoid coil 2 of the solenoid valve, so that electrical energy is unnecessarily consumed for holding the armature of the solenoid valve in a fully open position. In section (2), the level of the definable, variable (lower) current threshold is gradually reduced by means of the inventive method or device 220 in order to change the level of the definable, variable (lower) current threshold for determining a (new, adjusted) lower current threshold US (see section (3) of the current profile). In addition to the stepwise reduction of the level of the definable, variable (lower) current threshold, the upper current threshold OS is also gradually reduced at the same time, in particular by the same amount as the definable, variable (lower) current threshold US.In section (2) of the current curve shown in Figure 4, the armature of the solenoid valve is released from a rest state in the fully open position when the definable, variable (lower) current threshold is less than the lower minimum current threshold i. m, min of the solenoid coil 2 of the solenoid valve (see circling). According to the invention, the release of the armature is detected as a change in the state of the armature and, based on the definable, variable current threshold at which the change in the state of the armature is detected, a new lower current threshold US of the current band B and a new upper current threshold OS are determined, in particular determined in such a way that when the solenoid coil 2 of the solenoid valve is energized with a current intensity equal to the current band B, the armature of the solenoid valve is held in the fully open position (see section (3) of the current curve shown in Figure 4). In this example, the determined, adjusted lower current threshold US in section (3) is greater than the definable, variable (lower) current threshold at which the change in the state of the armature was detected.
[0056] Figure 5 schematically discloses a vehicle 200, wherein the vehicle 200 comprises two pressure fluid reservoirs 210a, 210b, each having a valve unit 100 with a solenoid valve for controlling a flow of a pressure fluid storable in the respective pressure fluid reservoir 210a, 210b. Furthermore, the vehicle 200 has a device 220 designed according to the invention, wherein the device 220 is further designed to determine at least the lower current threshold US for the solenoid valve of the respective valve unit 100 for the two pressure fluid reservoirs 210a, 210b. In particular, the respective lower current threshold required for keeping the respective solenoid valve (fully) open, in particular the lower minimum current threshold, can thus be determined by means of the method according to the invention. The vehicle 200 can also be understood as a stationary energy unit, for example, a power generator or a fuel cell heater.
Claims
Claims 1. Procedure for determining at least one lower Current threshold (US) of a current band (B) of a solenoid coil (2) of a solenoid valve for a valve unit (100) fluid-communicating with a pressure fluid accumulator (210a, 210b), in particular of a vehicle (200), wherein when an electric current at the level of the current band (B) flows through the solenoid coil (2), an armature of the solenoid valve movable by the solenoid coil (2) is held in a fully open position, wherein the movable armature, when transitioning between a closed position of the armature and the fully open position of the armature, comprises at least one state of motion and, in the fully open position, a state of rest, wherein the method comprises: - active energizing of the solenoid coil (2) of the solenoid valve, wherein the active energizing of the solenoid coil (2) of the solenoid valve occurs upon detection of an electric current flowing through the solenoid coil (2) at the level of an upper The current threshold (OS) of the current band (B) is switched off, and the solenoid coil (2) of the solenoid valve is actively energized again by the electrical energy source when an electric current flowing through the solenoid coil (2) is detected at a level of a definable, variable current threshold which is lower than the upper current threshold (OS). - Changing (10) the level of the definable, variable current threshold, - continuous measurement (20) of a measurement signal to detect a change in the state of the armature of the solenoid valve between at least one moving state and the rest state of the armature, - Determining (40) at least the lower current threshold (US) of the current band (B) based on the definable, variable current threshold when the change in state of the solenoid valve armature is detected due to the change in the definable, variable current threshold (30). Method according to claim 1, characterized in that the level of the definable, variable current threshold is temporarily increased stepwise and / or temporarily decreased stepwise to change (10) the level of the definable, variable current threshold for determining (40) the lower current threshold. Method according to any of the preceding claims, characterized in that, for detecting (30) the change in state of the solenoid valve armature between the at least one moving state and the rest state of the armature, the electric current flowing through the solenoid coil (2) is considered as the measurement signal.A method according to any of the preceding claims, characterized in that a time constant of the current flowing through the solenoid coil (2) of the solenoid valve is considered for detecting (30) the change of state of the armature. A method according to any of the preceding claims, characterized in that a current frequency of the current flowing through the solenoid coil (2) of the solenoid valve is considered for detecting (30) the change of state of the armature. A method according to any of the preceding claims, characterized in that. that for detecting (30) the change of state of the armature, a frequency spectrum of the current flowing through the solenoid coil (2) of the solenoid valve is considered. Method according to one of the preceding claims, characterized in that the upper current threshold of the current band (B) is adapted to the determined lower current threshold of the current band (B) of the solenoid valve. Method according to one of the preceding claims, characterized in that, for detecting (30) the change of state of the armature of the solenoid valve, a value based on the measurement signal is compared with a limit value. Method according to one of the preceding claims, characterized in that, for detecting (30) the change of state of the armature of the solenoid valve, a classification method is applied. Device (220) for determining at least one lower Current threshold (US) of a current band (B) of a solenoid coil (2) of a solenoid valve for a valve unit (100) communicating with a pressure fluid accumulator (210a, 210b), in particular of a vehicle (200), wherein the device (220) comprises: - an electrical energy source (222) for providing electrical energy for actively energizing the solenoid coil (2) of the solenoid valve, - a sensor (224) for detecting an electric current flowing through a solenoid coil (2) of a solenoid valve, - a control unit (226) for switching off the electric current flowing through the solenoid coil (2) of the solenoid valve when an upper current threshold (OS) of a current band (B) of the solenoid valve is exceeded, as well as for actively energizing the solenoid coil (2) of the solenoid valve when a definable, variable current threshold is undershot, - a current change unit (228) for changing the level of the definable, variable current threshold, - a measuring unit (230) for measuring a measurement signal to detect a change in the state of the armature of the solenoid valve between at least one moving state and a rest state of the armature, - a determination unit (232) for determining at least the lower current threshold (US) of the current band (B) based on the definable, variable current threshold when the change in state of the solenoid valve armature is detected due to the change in the definable, variable current threshold, wherein the device (220) is configured to perform a method according to one of the preceding claims. Vehicle (200), wherein the vehicle (200) comprises: - at least one pressure fluid accumulator (210a, 210b) with one valve unit (100) each with a solenoid valve for controlling the flow of a pressure fluid that can be stored in the pressure fluid accumulator (210a, 210b), - a device (220) configured according to claim 10, wherein the device (220) is further configured to determine at least the lower current threshold (US) for the solenoid valve of the valve unit (100) for the at least one pressure fluid accumulator (210a, 210b).