DE102022202189A1 - Method for determining a lower current threshold value of a current band of a magnet coil of a magnet valve for a valve unit, device and vehicle that communicates fluidly with a pressurized fluid reservoir - Google Patents

Abstract

Method for determining a lower current threshold value (US) of a current band (B) of a magnet coil (2) of a magnet valve, the method having:- active energizing of the magnet coil (2) of the magnet valve, the active energization of the magnet coil (2) of the magnet valve being detection of an electric current flowing through the magnet coil (2) at the level of an upper current threshold value (OS) of the current band (B) is switched off, and renewed active energization of the magnet coil (2) of the magnet valve by the electrical energy source when an electric current through the magnet coil is detected (2) flowing electrical current at the level of a definable, changeable current threshold value, - changing (10) the level of the definable, changeable current threshold value, - permanent measurement (20) of a 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 quiescent state of the armature,- determining (40) the lower current threshold value (US) of the current band (B) based on the definable, changeable current threshold value if the change in the state of the armature of the magnet valve due to the change in the definable, changeable current threshold value is detected (30).

Description

State of the art

In order to store hydrogen for operating a vehicle, multiple 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 shut off 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 magnetic coil of the magnetic valve, the magnetic valve closes automatically, e.g. by spring force. This behavior is necessary for safety reasons, but has the disadvantage that current must flow through the solenoid coil continuously when the vehicle is being driven in order to keep the solenoid valve open. As a result, a small amount of electrical energy is permanently consumed.

It is a constant effort to keep the actual required electrical power of a component particularly low. Furthermore, valve units or solenoid valves of the valve units are subject to technical tolerances, so that a current which has to flow through the solenoid coil in order to keep the solenoid valve open can vary.

Disclosure of 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.

Further features and details of the invention result from the dependent claims, the description and the drawings. Features and details that are 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 the disclosure of the individual aspects of the invention is or can always be referred to alternately.

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 fluid-communicating valve unit with a pressure fluid reservoir, in particular of a vehicle, with an electric current flowing through the magnetic coil at the level of the current band an armature of the magnet valve that can be moved by the magnet coil can be held in a fully open position, the movable armature including at least one state of motion when transferring between a closed position of the armature and the fully open position of the armature, and a state of rest in the fully open position. As a step, the method includes actively energizing the magnet coil of the magnet valve, the active energization of the magnet coil of the magnet valve being switched off when an electric current flowing through the magnet coil is detected at the level of an upper current threshold value of the current band. The method also includes, as a step, a renewed, active energizing of the magnetic coil of the magnetic valve by the electrical energy source when it is detected, in particular when it is detected that the electric current flowing through the magnetic coil has fallen below a definable, changeable current threshold value, which is lower than the upper one Current threshold is. Furthermore, one step of the method according to the invention is changing the level of the definable, variable current threshold value or changing the level of the definable, variable current threshold value and (additionally) changing the level of the upper current threshold value. In addition, a further step of the method is a permanent measurement of a measurement signal, in particular a permanent 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. In addition, the method includes as a step a determination of (at least) the lower current threshold value of the current band based on the definable, changeable current threshold value if the change in the state of the armature of the magnet valve due to the change in the definable, changeable current threshold value is detected, in particular (in advance of time) was detected .

The method steps described above and below can, insofar as technically reasonable, be carried out individually, together, once, several times, in parallel and/or one after the other in any order.

In particular, it is also conceivable that the method according to the invention and/or the device according to the invention for determining (at least) a lower current threshold value of a current band of a magnet coil of a magnet valve for a valve unit of a stationary energy unit that communicates fluidly with a pressurized fluid reservoir, e.g. a power generator or a fuel cell heating system, is used .

The valve unit is in particular with at least one pressure fluid reservoir, for example. The vehicle ges or a stationary energy unit, fluidically connectable or connected.

A fully open position of the armature is to be understood in particular as 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 at a maximum. In the fully open position, the armature of the solenoid valve is in the quiescent state, i. H. at rest or substantially at rest. The armature of the solenoid valve can also be understood as a magnet armature. In particular, a state of movement of the armature is to be understood as a state of the armature in which the armature moves, in particular along an axis of the armature, for example from the closed position to the fully open position. In other words, the armature is not at rest in the moving state. The closed position of the armature is to be understood in particular as 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 at a maximum, for example at a minimum.

If a change in the state of the armature of the solenoid valve, which occurred due to the change in the definable, changeable current threshold value, has been detected, the lower current threshold value is determined in particular based on this definable, changeable current threshold value in such a way that the movable armature at the lower current threshold value determined therefrom in the fully open position. The expression “based” in “the lower current threshold value is determined in particular based on this definable, changeable current threshold value” is intended to express in particular that this definable, changeable current threshold value is, for example, multiplied by a factor, or an offset is added, or, for example, the previous, definable, changeable current threshold value is used as the lower current threshold value.

The active energizing of the magnetic coil of the magnetic valve, the switching off of the active energizing of the magnetic coil when the upper current threshold value of the current band is detected or detected, and when the definable, changeable current threshold value is recognized or detected, the renewed, active energizing of the magnetic coil is in particular a repeating process of the method according to the invention. In other words, the magnetic coil of the magnetic valve can be actively energized in a pulsating manner. A dynamic change in the inductance of the magnetic coil can thus be brought about when the armature starts to move. The electrical current flowing through the magnetic coil can have a periodic waveform, in particular a sawtooth-like or essentially sawtooth-like current waveform, or else a sinusoidal current waveform in the case of pulsating, active energizing. The pulsating, active energizing of the magnet coil of the magnet valve takes place in particular to determine the lower current threshold value by means of the method according to the invention (calibration mode).

However, the magnetic coil of the magnetic valve can in particular also be actively energized in a pulsating manner during normal operation of the magnetic valve in order to (permanently) hold the movable armature of the magnetic valve in the fully open position. Advantageously, a mean current that is permissible for the magnet coil can be implemented in a particularly simple manner by the pulsating energization of the magnet coil of the magnet valve. The electrical energy for the active energizing can be provided by an electrochemical store, for example a battery in the vehicle.

The active energizing of the magnetic coil of the magnetic valve can be switched on and off by actuating an electrical switch, for example a field effect transistor.

With the method according to the invention, at least the respective lower current threshold value of a current band required for holding a respective solenoid valve in 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, power consumption of a respective solenoid valve of the plurality of solenoid valves, for example solenoid valves on hydrogen cylinders of a fuel cell vehicle, can be particularly advantageously low, preferably minimized. In particular, each solenoid valve is only supplied with the necessary, lower minimum electrical current (or lower minimum current intensity) of the current band. Preferably, the lower current band current threshold for a solenoid coil is a lower minimum current band current threshold or a substantially lower minimum current band current threshold at which the armature of the solenoid valve can (barely) be held in the fully open position.

In addition to the lower current threshold value, the method according to the invention can also be used to determine the upper current threshold value, in particular as a function of the determined lower current threshold value. Thus, the power consumption of a respective solenoid valve of the plurality of solenoid valves, e.g net coils of the solenoid valves are actively energized in a pulsating manner in normal operation of the solenoid valves.

The change in state of the armature between the moving state and the resting state of the armature can also be understood as a state transition. It can be advantageous if, in a method according to the invention, the state change of the armature is a change of the armature from the rest state to the movement state or a change of the armature from the movement state to the rest state.

In particular, the definable, changeable current threshold value can be understood as a temporary lower current threshold value of the current band in order to be able to determine the lower current threshold value of the current band for normal operation of the solenoid valve.

In addition to switching off the active energization of the magnet coil of the magnet valve when the electric current flowing through the magnet coil is detected at the level of the upper current threshold value of the current range, a freewheeling circuit connected in parallel with the magnet coil can be switched to be electrically conductive ("closed") at the same time or essentially at the same time, so that the electrical current flowing through the magnetic coil of the magnetic valve can be reduced in a particularly advantageous manner due to the ohmic resistance of the magnetic coil. The freewheeling circuit has, for example, a “freewheeling transistor” for electrically conductive switching of the freewheeling circuit. In particular, the free-wheeling circuit is electrically non-conductive (“open”) during the active energization of the magnetic coil of the magnetic valve. A device according to the invention can have such a freewheeling circuit.

The time interval of the active energizing of the magnetic coil of the magnetic valve is in particular also referred to as the rise interval. The time interval from switching off the active energization of the magnet coil when the upper current threshold value has been detected until the magnet coil is actively energized again when the definable, changeable current threshold value or the lower current threshold value has been detected is also referred to as the fall interval . The dropout interval may also be referred to as the freewheeling interval when a freewheeling circuit is employed.

In the course of the service life of a solenoid valve, the properties of the solenoid valve can change, so that the lower current threshold value and/or the upper current threshold value, i. H. the current band, has to be adjusted so that the solenoid valve or a valve unit with such a solenoid valve can work particularly advantageously and the energy consumption is particularly low. Advantageously, a device according to the invention can be designed to determine and, if necessary, adapt a particularly advantageous lower current threshold value and/or upper current threshold value at regular time intervals. In other words, self-calibration can take place.

Advantageously, the method according to the invention makes use of the fact that when the armature changes its state between the moving state and the resting state, there is a change in the inductance of the magnet coil, since the inductance of the magnet coil depends, among other things, on the distance between the armature and the magnet coil. A movement of the armature can thus itself bring about a change in a current profile of the electrical current flowing through the magnet coil compared to the stationary armature. In particular, the 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 recognized or detected based on the change in the current profile. The change in the current flow can be used as an indicator of the movement of the armature.

It can be advantageous if, in a method according to the invention, the height of the definable, changeable current threshold value is temporarily increased in steps and/or temporarily decreased in steps to change the height of the definable, changeable current threshold value for determining the lower current threshold value. 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 thus be triggered in a particularly simple manner, in order to thus detect a movement of the armature. In addition to increasing the level of the definable, changeable current threshold value stepwise at least at times, the upper current threshold value can also be increased stepwise at the same time for determining the lower current threshold value. In addition to reducing the level of the definable, changeable current threshold value stepwise at least temporarily, the upper current threshold value can also be reduced stepwise at the same time for determining the lower current threshold value. In other words, the current band can in particular be shifted for determining the lower current threshold value. The lower current threshold value can thus be determined particularly quickly.

Advantageously, in an inventive method for detecting the State change of the armature of the solenoid valve between the at least one state of motion and the rest state of the armature as a measurement signal of the electric current flowing through the solenoid coil are considered. In other words, the course of the electric current flowing through the magnetic coil can be observed. Thus, when a change in the current profile of the electrical current flowing through the magnetic coil is detected, it is particularly easy to draw conclusions about a change in the state of the armature of the magnetic valve. The electric current flowing through the magnetic coil can be understood in particular as the electric current flowing directly through the magnetic coil. However, it is also conceivable that a current dependent on the electric current flowing through the magnetic coil is considered as the measurement signal.

A time constant of the current flowing through the magnet coil of the magnet valve can advantageously be considered in a method according to the invention for detecting the change in the state of the armature. The decay of the electric current flowing through the magnetic coil after the electric current flowing through the magnetic coil has been switched off (when the upper current threshold value is detected) follows an exponential course. The time constant for the exponential profile can be determined from the ratio of ohmic resistance, in particular ohmic resistance of the magnet coil, and the inductance of the magnet coil of the magnet valve. If the inductance decreases, e.g. because the armature detaches from the valve unit stop, the time constant of the exponential decay also decreases as a result. This time constant can be determined, for example, using a suitable filter routine, for example 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.

A current frequency of the current flowing through the magnet coil of the magnet valve can be considered with particular advantage in a method according to the invention for detecting the change in the state of the armature. For this purpose, for example, the time can be determined that elapses between the active energization of the magnetic coil of the magnetic valve by the electrical energy source when an electric current flowing through the magnetic coil is detected at the level of a definable, changeable current threshold value and a renewed active energization of the when a through the Solenoid flowing, electric current passes in the amount of a definable, changeable current threshold. In other words, the period can be determined and considered, in particular the period of a sawtooth-like or essentially sawtooth-like current profile of the electric current flowing through the magnet coil. For example, if the time constant of the exponential course of the electric current flowing through the magnet coil decreases, this leads to a time reduction in the decay interval, in particular the free-running interval. A change in the state of the armature between the state of rest and the state of movement can thus advantageously lead to a recognizable change in the current frequency.

According to a further preferred embodiment, a frequency spectrum of the current flowing through the magnet coil of the magnet valve can be considered in a method according to the invention for detecting the change in the state of the armature. For example, the course of the electric current flowing through the magnetic coil will show a strictly exponential behavior when the armature is stationary, whereas a movement of the armature will lead to a deviation from the exponential behavior. A change in the state of the armature between the state of rest and the state of movement can thus advantageously lead to a recognizable change in the frequency spectrum of the current profile.

In a method according to the invention, the upper current threshold value of the current band can advantageously be adapted to the determined lower current threshold value of the current band of the solenoid valve. The energy consumption of a magnet coil that is actively energized in a pulsating manner during normal operation of the magnet valve can thus be particularly low. For example, the upper current threshold value can be determined in such a way that a desired, average current value that is permissible for the magnet coil results.

In a method according to the invention for detecting the change in the state of the armature of the magnet valve, a value based on the measurement signal can be compared with a limit value with particular advantage. The limit value can also be understood as a threshold value.

According to a further preferred embodiment, a classification method can be used in a method according to the invention for detecting the change in the state of the armature of the magnet 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 built using an algorithm that is based on the training data. In this way, patterns and regularities can be recognized in the training data and also unknown data can be evaluated.

According to a second aspect, the present invention shows a device for determining (at least) a lower current threshold value of a current band of a magnet coil of a magnet valve for a valve unit that communicates fluidly 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 magnet coil of the magnet valve. The device also includes a sensor for detecting an electric current flowing through a magnetic coil of a magnetic valve. In addition, the device includes a control unit for switching off the electric current flowing through the magnetic coil of the magnetic valve when an upper current threshold value of a current band of the magnetic valve is exceeded, and for actively energizing the magnetic coil of the magnetic valve when a definable, changeable current threshold value is undershot. The device also includes a current changing unit for changing the level of the definable, changeable current threshold value, and a measuring unit for measuring a measuring signal for detecting a change in the state of the armature of the solenoid valve between at least one movement state and one rest state of the armature. The device also has a determination unit for determining (at least) the lower current threshold value of the current band based on the definable, variable current threshold value if the change in the state of the armature of the magnet valve is detected due to the change in the definable, variable current threshold value. In addition, the device is designed to carry out a method according to the invention for determining at least the lower current threshold value of the current band for the magnet coil of the magnet valve of the valve unit of the pressure fluid reservoir, in particular of the vehicle.

In particular, the valve unit has a housing for accommodating the solenoid valve. Furthermore, the valve unit has in particular a fluid inlet and a fluid outlet, wherein the fluid inlet can be fluidically connected to the fluid outlet by means of the solenoid valve via a fluid channel. In particular, the solenoid valve is also self-closing, i. H. if no current flows through a magnetic coil of the magnetic valve, the magnetic valve closes automatically, e.g. by spring force.

The electrical energy source is in particular a battery, for example a vehicle battery.

The sensor for detecting the electrical current flowing through the magnetic coil of the magnetic valve can be a current sensor, for example.

The control unit is designed in particular to switch on and/or switch off the active energizing of the electric current flowing through the magnetic coil of the magnetic valve. Furthermore, the control unit can additionally be designed to switch a freewheeling circuit to be electrically conductive and/or electrically non-conductive.

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 definable, changeable current threshold value(s).

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 magnet coil of the magnet valve for at least one valve unit that communicates fluidly with a pressurized fluid reservoir, e.g. a high-pressure hydrogen tank.

The device according to the second 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.

According to a third aspect, the present invention shows a vehicle, wherein the vehicle has at least one pressure fluid reservoir with a valve unit with a solenoid valve for controlling a flow of a pressure fluid that can be stored in the pressure fluid reservoir, in particular a plurality of pressure fluid reservoirs, each with a valve unit with a solenoid valve for controlling a flow a pressure fluid that can be stored in a respective pressure fluid reservoir of the plurality of pressure fluid reservoirs. The vehicle also includes a device designed according to the invention, the device also being 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, the device according to the invention is designed with several pressure fluid reservoirs to determine (at least) the lower current threshold value for the solenoid valve of the respective valve unit for at least two pressure fluid reservoirs of the plurality of pressure fluid reservoirs.

The vehicle can also be understood as a stationary energy unit.

The storable pressurized fluid can be gaseous hydrogen, for example. In particular, that is Pressure fluid stored under high pressure in the pressure fluid reservoir. Furthermore, the valve unit is in particular arranged directly on the pressure fluid reservoir, for example a bottle neck of the pressure 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.

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.

Further measures improving the invention result from the following description of some exemplary embodiments of the invention, which are shown schematically in the figures. All of the features and/or advantages resulting from the claims, the description or the drawings, including structural details, spatial arrangements and method steps, can be essential to the invention both on their own and in various combinations. It should be noted that the figures are only descriptive and are not intended to limit the invention in any way.

• 1 ein Ablaufdiagramm,
• 2 eine Vorrichtung,
• 3 ein sägezahnartiges Stromprofil,
• 4 einen Verlauf eines Stromes durch eine Magnetspule vor, während und nach dem Bestimmen des unteren Stromschwellwerts, und
• 5 ein Fahrzeug.

They show schematically:

• 1 a flowchart,
• 2 a device
• 3 a sawtooth current profile,
• 4 a course of a current through a magnetic coil before, during and after determining the lower current threshold value, and
• 5 a vehicle.

In the following figures, identical reference symbols are used for the same technical features, also from different exemplary embodiments.

1 schematically discloses a flow chart 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 e.g. 3 ) a solenoid coil 2 of a solenoid valve for a valve unit 100, e.g. 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 that can be moved by the magnetic coil 2 can be held or is held in a fully open position, the movable armature being able to move when it is transferred between a closed position of the Anchor 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. 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 also includes, as steps, in particular as repetitive steps, active energizing of the solenoid coil 2 of the solenoid valve, with the active energizing of the solenoid coil 2 of the solenoid valve upon detection of an electric current flowing through the magnet coil 2 in the amount of an upper current threshold value OS of the current band B is switched off, and renewed active energization of the magnet coil 2 of the magnet valve by the electrical energy source upon detection of an electric current flowing through the magnet coil 2 in Level of a definable, changeable current threshold value, which is lower than the upper current threshold value OS. Furthermore, for determining the lower current threshold value US or for determining the lower current threshold value US and the upper current threshold value OS, a measurement signal, e.g. the electric current flowing through the magnet coil 2, is used to detect a change in the state of the armature of the magnet valve between the at least one State of motion and the state of rest of the armature for the time of determining the lower current threshold US or for the time of determining the lower current threshold US and the upper current threshold OS continuously measured 20. In this example, it is assumed that the movable armature of the solenoid valve initially (at the start), ie for the current band B resulting from the upper current threshold value OS and the current, definable, changeable (starting) current threshold value, is held in a fully open position. As shown in the flowchart, for determining the lower current threshold value US or for determining the lower current threshold value US and the upper current threshold value OS, the level of the definable, changeable current threshold value is now so frequent, in particular repeatedly, by one (current) step reduced 10 or lowered until the change in the state of the armature of the solenoid valve, here in this example a change in the state of the armature from the idle state to the moving state, is detected (positive) on the basis of the change in the definable, changeable current threshold value 30. However, it is also conceivable that the upper current threshold value is also successively changed, in particular also reduced or increased. If the change in the state of the armature of the solenoid valve has been detected due to the change in the definable, changeable current threshold value, then the lower current threshold value US of the current band B is based on determined 40 from the definable, changeable current threshold value, in which case the upper current threshold value OS can also be determined or adjusted. In particular, the upper current threshold value OS is adapted to the specific lower current threshold value US of the current band B of the solenoid valve. For example, the previous, definable, changeable current threshold value can be determined as the lower current threshold value US of the current band B 40. In addition, in the method according to the invention, the determined lower current threshold value US and/or the determined upper current threshold value OS are stored in a memory in one step 50. Advantageously For example, a time constant and/or a frequency spectrum and/or a current frequency of the current flowing through the magnet coil of the magnet valve can be considered for detecting the change in the state of the armature. In addition, in an optional step, upon detection 60 that a definable minimum threshold value, e.g an error memory entry can be made 80.

2 discloses a device 220 for determining at least 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 of a magnet coil 2 of a magnet valve for a valve unit 100, e.g . 4 ). The device 220 has an electrical energy source 222, for example 12 volts - on-board voltage of the vehicle, for providing electrical energy for an active energizing of the magnetic coil 2 of the magnetic valve. Solenoid coil 2 is in 2 represented by an ohmic resistance and an (electrical) coil. Furthermore, the device 220 includes an ammeter as a sensor 224 for detecting an electric current flowing through a magnetic coil 2 of a magnetic valve. Furthermore, the device 220 comprises a control unit 226 for switching off the electric current flowing through the magnetic coil 2 of the magnetic valve when an upper current threshold value OS of a current band B of the magnetic valve is exceeded, and for actively energizing the magnetic coil (2) of the magnetic 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 switch on (active current supply) the electric current flowing through the magnetic coil 2 of the magnetic valve. In addition, for the time during which the electrical current flowing through the solenoid coil 2 of the solenoid valve is switched off, a "freewheeling transistor" 242 connected in parallel with the solenoid coil 2 can be switched on, e.g. by the control unit 226, so that the current flowing through the solenoid coil 2 of the solenoid valve particularly advantageously reduces the electrical current flowing due to the ohmic resistance. Device 220 also includes a current changing unit 228 for changing at least the level of the definable, changeable current threshold value and a measuring unit 230 for measuring and evaluating a measuring signal obtained by sensor 224 for detecting a change in the state of the armature of the solenoid valve between at least one movement state and one rest state of the armature . To detect the change in the state of the armature of the solenoid valve, a value based on the measurement signal can be compared with a limit value, for example. As an alternative or in addition to the comparison with a limit value, it is possible to use a classification method (machine learning; for example a neural network) to detect the change in the state of the armature of the solenoid valve. Device 220 also includes a determination unit 232 for determining at least the lower current threshold value US of current band B based on the definable, changeable current threshold value, wherein device 220 is designed to use a method according to the invention for determining at least the lower current threshold value US of current band B for the magnet coil 2 of the solenoid valve. In particular, the sensor 224 and/or the current changing unit 228 and/or the measuring unit 230 and/or the determining unit 232 can also be part of the control unit 226 . Device 220 can also have a memory, in particular non-volatile memory, for storing lower current threshold values US and/or for storing upper current threshold values OS and/or for storing definable, changeable current threshold value(s).

3 discloses a sawtooth current profile of an electric current i _m flowing through a magnet coil 2 of a magnet valve over time t. When the electric current i _m flows through the magnetic coil 2 in the amount of a current band B defined by an upper current threshold value OS and a lower threshold value US, an armature of the magnetic valve that can be moved by the magnetic coil 2 can be Open position are held, while at the same time in a simple way an average permissible current for the magnetic coil can be realized without damaging the magnetic coil.

4 discloses a time course of a flowing through a magnetic coil 2 (sawtooth-like gen) electric current i _m before (see section (1)), during (see section (2)) and after (see section (3)) the determination of an (adapted) lower current threshold value US by means of a method or a device according to the invention 220. The current intensity i _m , _min designates a lower minimum current threshold value of the current band B of the magnet coil 2 of the magnet valve at which the armature of the magnet valve can (barely) be held or is held in the fully open position. In the course of the lifetime, in particular at the beginning of a lifetime, of a solenoid valve, properties of the solenoid valve can change, so that the lower current threshold value US used for the operation of the solenoid valve or the solenoid coil 2 and/or the upper current threshold value OS, ie the current band B, must be adjusted, so that the solenoid valve or a valve unit 100 can work particularly advantageously with such a solenoid valve and the energy consumption is particularly low. In section (1) of the in 4 With the current curve presented, 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, min} of the 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 height of the specifiable, changeable (lower) current threshold value is gradually reduced by means of the method or the device 220 according to the invention in order to change the height of the specifiable, changeable (lower) current threshold value for determining a (new, adapted) lower current threshold value US (see section (3) of the current curve). In addition to the gradual reduction in the level of the definable, changeable (lower) current threshold value, the upper current threshold value OS is also gradually reduced at the same time, in particular by the same value as the definable, changeable (lower) current threshold value US. In section (2) of the in 4 According to the current curve presented, the armature of the solenoid valve releases from a resting state in the fully open position when the definable, changeable (lower) current threshold value is less than the lower minimum current threshold value i _{m, min} , of the solenoid coil 2 of the solenoid valve (see circle). According to the invention, the loosening of the armature is recognized as a change in the state of the armature and, based on the definable, changeable current threshold value at which the change in state of the armature is recognized, a new lower current threshold value US of the current band B and a new upper current threshold value 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 level of current band B, the armature of the solenoid valve is held in the fully open position (see paragraph (3) of in 4 illustrated current course). In this example, the determined, adjusted lower current threshold value US in section (3) is greater than the definable, changeable (lower) current threshold value at which the state change of the armature was detected.

5 schematically discloses a vehicle 200, the vehicle 200 comprising two pressurized fluid reservoirs 210a, 210b, each with a valve unit 100 with a solenoid valve for controlling a flow of a pressurized fluid that can be stored in the respective pressurized fluid reservoir 210a, 210b. Vehicle 200 also has a device 220 designed according to the invention, device 220 also being designed to determine at least the lower current threshold value US for the solenoid valve of the respective valve unit 100 for the two pressurized fluid reservoirs 210a, 210b. In particular, the respective lower current threshold value required for keeping the respective solenoid valve (completely) open, in particular the lower minimum current threshold value, 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 heating system.

Claims (11)

Method for determining at least one lower current threshold value (US) of a current band (B) of a magnet coil (2) of a magnet valve for a valve unit (100) that communicates fluidly with a pressurized fluid reservoir (210a, 210b), in particular of a vehicle (200), wherein when a electrical current at the level of the current band (B) through the magnetic coil (2), an armature of the magnetic valve that can be moved by the magnetic coil (2) can be held in a fully open position, the movable armature being able to be held in a fully open position when the armature is switched between a closed position 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, the method having: - active energizing of the magnetic coil (2) of the magnetic valve, wherein the active energizing of the magnetic coil (2) of the magnetic valve upon detection of a through the magnetic coil ( 2) flowing electrical current is switched off at the level of an upper current threshold value (OS) of the current band (B), and renewed active energization of the solenoid coil (2) of the solenoid valve by the electrical energy source when an electrical current flowing through the solenoid coil (2) is detected Current in the amount of a definable, changeable current threshold, which is less than the upper current threshold (OS) is, - changing (10) the level of the definable, changeable current threshold value, - permanent measurement (20) of a measurement signal for detecting a change in the state of the armature of the magnetic valve between the at least one movement state and the rest state of the armature, - determining (40) at least the lower current threshold value (US) of the current band (B) based on the definable, changeable current threshold value if the change in the state of the armature of the magnet valve is detected due to the change in the definable, changeable current threshold value (30). procedure after claim 1 , characterized in that the height of the definable, changeable current threshold value is temporarily increased step by step and/or temporarily decreased stepwise for changing (10) the height of the definable, changeable current threshold value for determining (40) the lower current threshold value. Method according to one of the preceding claims, characterized in that for the detection (30) of the state change of the armature of the magnet valve between the at least one movement state and the rest state of the armature, the electric current flowing through the magnet coil (2) is considered as the measurement signal. Method according to one of the preceding claims, characterized in that a time constant of the current flowing through the magnet coil (2) of the magnet valve is considered for the detection (30) of the change in the state of the armature. Method according to one of the preceding claims, characterized in that a current frequency of the current flowing through the magnet coil (2) of the magnet valve is considered for the detection (30) of the change in the state of the armature. Method according to one of the preceding claims, characterized in that a frequency spectrum of the current flowing through the magnet coil (2) of the magnet valve is considered for the detection (30) of the change in the state of the armature. Method according to one of the preceding claims, characterized in that the upper current threshold value of the current band (B) is adapted to the determined lower current threshold value of the current band (B) of the solenoid valve. Method according to one of the preceding claims, characterized in that a value based on the measurement signal is compared with a limit value in order to detect (30) the change in the state of the armature of the magnet valve. Method according to one of the preceding claims, characterized in that a classification method is used to detect (30) the change in the state of the armature of the magnetic valve. Device (220) for determining at least one lower current threshold value (US) of a current band (B) of a magnet coil (2) of a magnet valve for a valve unit (100) communicating fluidly with a pressurized fluid reservoir (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 magnetic coil (2) of the magnetic valve, - a sensor (224) for detecting an electric current flowing through a magnetic coil (2) of a magnetic valve, - a control unit (226) for switching off the electric current flowing through the magnetic coil (2) of the magnetic valve when an upper current threshold value (OS) of a current band (B) of the magnetic valve is exceeded, and for actively energizing the magnetic coil (2) of the magnetic valve, if a definable, changeable current threshold value is undershot, - a current changing unit (228) for changing the level of the definable, changeable current threshold value, - a measuring unit (230) for measuring a measuring signal for detecting a change in the state of the armature of the solenoid valve between at least one state of movement and a state of rest of the armature, - A determination unit (232) for determining at least the lower current threshold value (US) of the current band (B) based on the definable, variable current threshold value when the change in the state of the armature of the magnet valve is detected due to the change in the definable, variable current threshold value, the device ( 220) is designed to carry out a method according to one of the preceding claims. Vehicle (200), the vehicle (200) having: - at least one pressure fluid reservoir (210a, 210b), each with a valve unit (100) with a solenoid valve for controlling a flow of a pressure fluid that can be stored in the pressure fluid reservoir (210a, 210b), - one after claim 10 trained device (220), wherein the device (220) is also designed to determine at least the lower current threshold value (US) for the solenoid valve of the valve unit (100) for the at least one pressure fluid reservoir (210a, 210b).

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