EP3898377B1 - Valve assembly and method for controlling the air suspension level of a rail vehicle - Google Patents

Description

technical field

The invention relates to a valve arrangement and a method for controlling the air suspension level of a rail vehicle.

State of the art

In the prior art, the use of air suspension for rail vehicles is known in principle. Such air suspension systems are usually implemented in rail vehicles in the form of air spring bellows arranged between the car body and the running gear or bogie of a car and serve as secondary suspension for the elastic mounting of the car body relative to the running gear or bogie. They largely decouple the car body from unevenness in the track system through the passive suspension properties and compressibility of the statically loaded air spring bellows and/or their actively controlled loading and venting during driving. Actively controlled pressurization and venting of the spring bellows also makes it possible to compensate for changes in the level caused by changes in the load on a wagon, i.e. the relative height of the wagon body relative to the chassis frame.

the DE 22 16 544 C3 discloses air suspension for rail vehicles in which the loading and venting of an air suspension device is controlled by means of a level control valve actuated mechanically via a lever and a measuring linkage connected to the car body and the running gear. Such a purely mechanical valve control arrangement is structurally relatively complex and due to the mechanical control in the control behavior at the same time inflexible and only constructively changeable. In the technical control design of such a purely mechanical valve control arrangement, there is also a design conflict between the fastest possible control behavior in the event of significant changes in the load - for example when loading a wagon or when people enter the platform while stationary - on the one hand and a control that is as air-saving as possible and designed to be rather slow-acting when driving - for example in the case of purely short-term shocks due to unevenness in the track system - on the other hand. the AU 001983018195B discloses a comparable technical solution with an air control valve actuated mechanically via a lever and a linkage connected to the car body and the running gear.

the DE 296 20 200 U1 discloses an electronic control for air suspension for rail vehicles with an electropneumatic valve, in which the height of a vehicle body relative to a bogie or chassis is detected by means of a height sensor that delivers an electrical measurement signal to control electronics. In order to avoid the design conflict already explained, the response time or characteristics of the system in stationary operation versus driving operation are switched by means of control electronics. The functioning of the control device should be designed in such a way that, on the one hand, when the vehicle is stationary (static loads), a very precise height position of the vehicle body can be set, while on the other hand, while driving (dynamic loads), a non-reaction to, for example, rolling movements is achieved. A concrete control model for the two operating modes is from the DE 296 20 200 U1 not disclosed for this.

The Austrian publication AT 503 256 B1 and the documents associated with it as a common priority application WO2007/104370 A1 and EP 1 993 862 B1 disclose various designs of an electronic air spring control for a rail vehicle with a valve that can be actuated mechanically via a linkage. In order to avoid the design conflict between the fastest possible control behavior in the event of load changes when stationary and air-saving control when driving, the documents disclose the additional arrangement of a control valve or a controllable switching means in the connecting line between the mechanically actuated valve and at least one air spring to enable a Throttling of the air exchange between the mechanically operable valve and the at least one air spring. Alternatively, the documents also disclose the arrangement of two control valves or controllable switching means, each in the supply and exhaust air line of the mechanically actuated valve. The air spring controls disclosed by these publications are structurally relatively complex and require a relatively large amount of space because the electrically or electronically controllable switching means or control valves are only provided as additional means in addition to the mechanically actuatable valve. The pressurization and venting is primarily controlled by the valve, which can be actuated mechanically via a linkage, as a result of which the system is designed to be relatively inflexible in terms of function and construction. For example, it is not possible to act on the air spring independently of the existing carriage lift, for example for pure leveling on high platforms. The mechanical actuation via a linkage and lever is also subject to relatively high wear due to the design. Finally, the documents do not disclose any control model for the electrical or electronic actuation of the additional control valves or controllable switching means for throttling the air exchange. Such must be based on the by the AT503256B1 ,

WO2007/104370 A1 and EP 1 993 862 B1 disclosed prior art to be developed.

The Austrian publication AT 508 044 A1 and the documents associated with it as a common priority application WO2010/115739 A1 and EP 2 416 997 B1 disclose a method for controlling an air spring arrangement of a vehicle, in which a height control behavior assigned to a specific state of the vehicle is set by activating at least one valve of the air spring arrangement, which can be an electronically controllable proportional valve. Discrete status parameters are derived from the status of the vehicle and are combined into parameter sets, with each parameter set being assigned a defined height control behavior. The height control behavior is specified and set in a targeted manner by changing a defined step-like progression of valve characteristics of the proportional valve on the basis of the limited number of parameter sets. The behavior of the proportional valve is shown here in the simulation of a mechanically actuated valve exclusively as a function of the control deviation. The realization of an electronic control with non-linear valve characteristics with a The step-like progression defined requires the prior modeling of corresponding control profiles as a series of fixed values in relation to the discretized state parameters, with the corresponding measured values having to be collected in time-consuming preliminary tests and the required manipulated variables for each desired valve characteristic curve having to be determined iteratively, for example. Furthermore, the specification of a fixed control profile as a series of fixed values has the further disadvantage that disturbance variables not covered by the respective control profile (e.g. changed ambient and system temperatures or component tolerances caused by wear effects) cannot or only insufficiently be taken into account.

Disclosure of Invention

The invention is based on the object of avoiding the disadvantages presented. In particular, a system for controlling the air suspension level of a rail vehicle that is simple in terms of design and can be easily parameterized is to be provided.

The object is achieved according to the invention by a valve arrangement according to claim 1 and a method according to claim 12. Advantageous developments of the invention are specified in the dependent claims.

The core of the invention is a valve arrangement for controlling the air suspension level of a rail vehicle, comprising a proportional directional control valve, a sensor means for continuously detecting a distance variable representing the distance between a car body and a chassis or bogie of the rail vehicle, and a digital control device, the control device being set up by programming is used to determine a control deviation based on the actual distance detected by the sensor means and a comparison with a predeterminable target distance and for the continuous generation of manipulated variables as a linear function of the determined control deviation and the car body travel speed. A suitable sensor means continuously detects a distance variable representing the distance between a car body and a chassis or bogie of the rail vehicle and converts this into a suitable electrical signal that can be processed by the digital control device. This can be, for example, an angle sensor that detects the distance of the car body from the chassis or bogie via a mechanical linkage by means of a lever, as is shown by the DE 296 20 200 U1 or the WO2010/115739 A1 is revealed. Such an angle sensor can continuously output the distance variable electrically as an analog signal or as an incremental signal to the control device. In the first case, the sensor signal is then discretized by the digital control device. Other suitable sensor means continuously detect the distance variable, for example inductively or optically, and output this to the control device as an analog or incremental electrical signal value. The control deviation is determined by continuously comparing the actual distance detected by the sensor means—which represents the controlled variable within the closed control loop—with the definable target distance—which represents the reference variable within the closed control loop. The control deviation can be taken into account within the linear control function, for example as a proportional component (P element or P component). The car body travel speed corresponds to the change in the control deviation over time (rate of change) and can be taken into account within the linear control function, for example as a differential quotient corresponding to the change in the control deviation over time and therefore as a differential component (D element or D component).

The invention has recognized that this provides a system for controlling the air suspension level of a rail vehicle that is structurally simple and easy to parameterize. With a proportional directional control valve, all the pneumatic control functions required to control the air suspension level of a rail vehicle can be easily mapped in a single component, namely both the controlled pressurization of the air suspension device and the controlled venting of the air suspension device and finally also any desired shut-off of the air exchange in one certain loading or venting condition, for example when driving. Due to the implementation as a linear electronic control function of the determined control deviation and the vehicle body travel speed, there is also an effective and rapid adjustment of the changes in the level of the air suspension caused by changes in the loading of a wagon, i.e. the relative height of the vehicle body relative to the chassis frame or bogie is guaranteed without the need for complex parameterization. In particular, no complex modeling of a profile as a series of fixed values is required. Since the control deviation is determined in the simplest case by comparing the recorded actual distance with a single, fixed, definable value for the target distance, only one parameterization of this single fixed value (target distance) is required when using a standardized linear function at the same time. Due to the design as a closed control circuit (also referred to as a closed effective circuit) and the additional consideration of the vehicle body travel speed, the technical solution also has a very dynamic correction torque for compensating for disturbance variables that are not immediately detected. The digital control device required to implement the electronic control can also be easily integrated in a space-saving manner as a corresponding microcontroller in the housing of the proportional directional valve or a common housing for all components of the valve arrangement, for example as a "single-board computer (SBC)" in which all The electronic components required for operation (CPU, memory, input and output interfaces, A/D converters, DMA controllers, etc.) are combined on a single printed circuit board. The same applies to the sensor means, which can be integrated directly into the housing of the proportional directional valve or a common housing for all components of the valve arrangement, for example as an angle sensor, which can be actuated via a lever connected to a mechanical measuring linkage. The valve arrangement according to the invention can also be used to regulate the level of all pneumatically controllable air suspension devices for the suspension of a vehicle body or body in relation to a running gear or a chassis of vehicles, which allow regulated loading or venting, such as an air spring bellows, an arrangement of several air spring bellows or, for example, also an arrangement of one or more pneumatic suspension cylinders.

By including the car body travel acceleration as an additional control parameter of the linear function, a further increased dynamic and sensitivity of the response behavior of the valve arrangement is achieved. The car body travel acceleration corresponds to the change in the car body travel speed over time and can be taken into account within the linear control function, for example, as a further differential quotient corresponding to the change in the car body displacement speed over time and therefore as a further differential component.

The control behavior of the valve arrangement is made more flexible by the dynamics of the control function being selectable, specifiable or adjustable by changing the parameterization of individual control parameters or by setting a modification factor for the control effect, the manipulated variable or the detected actual distance. The changed parameterization takes place, for example, by setting a different target distance or setting or changing coefficients for one or more control parameters, i.e. the target distance, the control deviation, and/or the car body travel speed and/or the car body travel acceleration. Likewise, the dynamics of the control effect can alternatively be selected, specified or adjusted by setting a global modification factor for the control effect, the manipulated variable to be generated or the detected actual distance. In this case, the modification factor can be chosen to be damping or strengthening, so that the target dynamics of the regulation are reduced or increased as a percentage.

A more flexible control behavior of the valve arrangement is also achieved or further increased by the dynamics of the control function being selectable, specifiable or adjustable by intensity- and/or time-related filtering of the actual distance or the control deviation. Such filtering eliminates, for example, all actual distances or deviations below a definable size. In this case, the control responds only from a determinable actual distance or a determinable control deviation. Alternatively or cumulatively, the filtering can be designed as a temporal filtering, in which actual intervals or control deviations lead to control activity only after a determinable period of time. In this case, the control only responds to changes in the actual distances or control deviations with a specific time duration, as a result of which, for example, disturbance variables that only occur briefly (for example brief jolts when driving) are filtered out. Both filtering variants can also be combined with one another, so that the regulation only starts from an actual distance or a control deviation with a determinable size and a determinable time duration.

Since the dynamics of the control functions or the filtering can be selected, specified or adjusted based on the operating mode or the travel speed of the rail vehicle, a simple, automated assignment of different control dynamics to different operating modes is made possible. For example, a different target distance for stationary operation and driving operation can be specified automatically. Furthermore, increased control dynamics to compensate for load changes when stationary and slower control behavior with reduced air consumption when driving can be easily automated.

In a structurally advantageous embodiment of the valve arrangement, the proportional directional control valve is a 3-way proportional valve which has a venting position and an application position, each with continuously variable opening cross sections, and a blocking position. With such a directional control valve, all useful pneumatic control functions can be mapped simply and effectively, namely regulated pressurization of the air suspension device, regulated venting of the air suspension device and finally also blocking of the air exchange in a specific pressurized state of the air suspension device, for example to reduce the air consumption in the driving operation. When the air exchange is shut off while driving, the current loading of the air suspension device with a determinable pressure is "frozen" and this is limited to its passive suspension properties.

When using a proportional directional valve or a 3-way proportional valve, which assumes an open position in its rest position and thus also in the de-energized state and vents the air suspension device connected to it, a so-called "failsafe" function may be desired to ensure operational safety to prevent the system from venting in the event of a power failure. To implement such a fail-safe function, the vent connection of the proportional directional valve or the 3-way proportional valve is electronically controllable switching means downstream, which assumes a blocked position in the de-energized state and an open position in the actuated state. This reliably prevents unwanted venting of the valve and thus also of the entire system in the de-energized state. Such a switching means can be about a 2/2 switching valve.

Furthermore, fail-safe overpressure relief may be desired to further increase operational reliability. For this purpose, a working connection of the proportional directional valve or the 3-way proportional valve is connected via a connecting line to a combined charging/venting connection of at least one air suspension device and at the same time to the connecting line a measuring linkage that can be actuated mechanically via a lever and a measuring linkage connected to the car body and the running gear Switching means are arranged, which assumes a blocked position in its rest position and which switches from a lever position representing a determinable actual distance into an open position, connecting the connecting line to a vent outlet.

For connection to external electronic control systems, for example a higher-level train control, the control device is designed with at least one data communication interface that is compatible with at least one industrial protocol standard. This can be, for example, a wired fieldbus interface compatible with the industry standards Profibus, DeviceNet/ControlNet or CANopen, or a wired network interface (Industrial Ethernet) compatible with the industry standards Profinet, EtherNet/IP, Ethernet Powerlink or EtherCat. Such a data communication interface can be designed to be compatible with several protocol standards (data transmission protocols) at the same time. The data communication interface can also be in the form of a wireless data communication interface, such as an industrial WLAN interface (IWLAN).

For functional integration into external electronic control systems, for example a higher-level train control, the control device is set up in terms of programming for parameterization or for selecting, specifying or setting the dynamics of the control function or filtering via the data communication interface. This on the one hand enables remote parameterization or remote setting of the control dynamics via a higher-level train control. Furthermore, the functional integration of the valve arrangement enables a higher-level train control in that the control device receives the information about the current operating mode (driving mode/stationary mode) via the data communication interface and adjusts the control dynamics accordingly. Finally, this also enables interventions in the control dynamics at runtime by the higher-level train control system, for example by specifying a changed parameterization or dynamics of the control function or filtering for the control device at runtime.

A further safety function is provided by the fact that the proportional directional valve or 3/3-way proportional valve is designed with a sensor means for detecting the valve outlet pressure and the control device is programmed to determine a definable pressure drop and to generate an error signal and transmit it via the data communication interface. A defect in the air suspension device (e.g. a leak or the bursting of an air bag) results in a pressure drop on the working side of the proportional directional valve or 3-way proportional valve. This can be detected with a sensor means integrated into the valve for detecting the valve outlet pressure. In this case, the control device generates an error signal and transmits this via the data communication interface, for example to a higher-level train controller, as a result of which the vehicle driver or a control center are automatically informed of the defect.

A further core of the invention is a method for controlling the air suspension level of a rail vehicle with a proportional directional control valve, a sensor means for continuously detecting a distance variable representing the distance between the car body and a chassis or bogie, and a digital control device, with the control device using a comparison a control deviation is determined from the actual distances detected by the sensor means with a predeterminable target distance and a manipulated variable is continuously generated as a linear function of the determined control deviation and the car body travel speed becomes. The method ensures highly effective and rapid adjustment of the changes in the level of the air suspension caused by changes in the loading of a wagon, ie the relative height of the wagon body relative to the chassis frame or bogie, without the need for complex parameterization.

An increase in the possible dynamics and sensitivity of the response behavior of the control method is achieved by including the car body travel acceleration as an additional control parameter of the linear function.

A more flexible control behavior is achieved in that the dynamics of the control function can be selected, specified or adjusted by changing the parameterization of individual control parameters or by setting a modification factor for the control effect, the manipulated variable or the actual distance.

A further flexibilization of the control behavior is achieved in that the dynamics of the control function can be selected, specified or adjusted by intensity- and/or time-related filtering of the actual distance or the control deviation.

A simple, automated assignment of different control dynamics to different operating modes is made possible by the dynamics of the control functions and/or the filtering being selectable, specifiable or adjustable based on the operating mode or the traveling speed of the rail vehicle.

Fig. 1

eine schematische Rückansicht eines Teilbereichs eines Schienenfahrzeugs mit einer Luftfederung und einer Ventilanordnung;

Fig. 2

ein schematisches Schaltbild einer Ventilanordnung gemäß Fig. 1 zur Regelung des Luftfederungsniveaus eines Schienenfahrzeugs;

Fig. 3

Fig. 2 ein Diagramm mit einem Kennfeld des Regelungsverhaltens der Ventilanordnung.

Further advantages of the invention are presented in more detail below together with the description of preferred exemplary embodiments of the invention with reference to the figures. Show it:

1

a schematic rear view of a portion of a rail vehicle with an air suspension and a valve assembly;

2

a schematic circuit diagram of a valve assembly according to 1 for controlling the air suspension level of a rail vehicle;

3

2 a diagram with a map of the control behavior of the valve arrangement.

1 shows a portion of a rail vehicle in a schematic rear view. The valve arrangement 1 is arranged in the lower area of a car body 2 . It is mechanically connected to the chassis frame 5 via the lever 3 and the measuring linkage 4 . The chassis frame 5 can also be designed as a bogie. An air suspension device, which is formed by the two air spring bellows 6 and 6', is arranged as secondary suspension between the chassis frame 5 and the car body 2. The current stroke h of the secondary suspension 6 is therefore identical to the respective distance of the car body 2 from the chassis frame 5. Alternatively, the secondary suspension can also be designed as a single spring bellows. Below the chassis frame 5, the primary suspension 7 is arranged, through which the wheel axle 8 and the two wheels 9 and 9' are resiliently mounted relative to the chassis 5. The current stroke h of the secondary suspension 6 depends on the current loading of the car body 2 and is mechanically represented by the respective position of the measuring linkage 4 and the lever 3 connected to it.

2 shows a schematic circuit diagram of the valve assembly 1 with the lever 3 and the in 2 measuring linkage 4 shown only partially and the air spring bellows 6 and 6'. The components of the valve arrangement 1 are in a common housing—designated by a dashed frame. The measuring linkage 4 is articulated via the lever 3 on this housing. The 3/3-way proportional valve 11 is arranged inside the connecting line 10 for pressurizing and venting the two air spring bellows 6 and 6 ′ which are arranged outside the housing of the valve arrangement 1 and are connected to it via the connecting line 10 . The 3/3-way proportional valve 11 can be controlled via the proportional magnet 12 against the spring load of the mechanical return spring 13 and connects the air spring bellows 6 and 6' via the connecting line 10, each with variable valve opening cross sections in a switching position with the compressed air source 14 and in its initial and rest position with the vent outlet 15. The compressed air source 14 can be a compressed air pump, a compressor or, for example, an intermediate compressed air reservoir. The 3/3-way proportional valve 11 can also be switched to a blocked center position via the proportional magnet 12, in which the connecting line 10 is completely shut off. In its rest position in the de-energized state, the 3/3-way proportional valve 11 is fully switched to its venting position, in which the connecting line 10 is connected to the venting outlet 15 without being throttled. The electronic control of the proportional magnet 12 takes place via a control device which is integrated into the valve arrangement 1 as a microcontroller 16 . The microcontroller 16 is designed as a "single-board computer (SBC)" in which all the electronic components required for operation (CPU, memory, input and output interfaces, A/D converters, DMA controllers, etc.) are on a single Circuit board are summarized. The microcontroller 16 receives a continuous electrical signal from the angle sensor 17, which represents the current distance h of the car body 2 from the running gear frame 5. For this purpose, the angle sensor 17 is mechanically connected to the lever 3 and detects the current actual distance via its respective position. The microcontroller 16 is programmed to determine a control deviation e based on the actual distance recorded and transmitted by the angle sensor by comparing it with a definable setpoint distance and for continuously generating manipulated variables u for actuating the proportional magnet 12 of the 3/3-way proportional valve 11 as a linear function of the determined control deviation e and the vehicle body travel speed ẋ that can be derived from the change in the actual distance over time. If the target distance specified at runtime is constant over time, the vehicle body travel speed can also be derived directly from the change over time in the determined control deviation e. The car body acceleration ẍ , which can be derived from the change in the car body travel speed x over time, can also be taken into account as a further control parameter. In this case, each control parameter can be designed to be parameterizable via coefficients k ₁ , k ₂ , k ₃ , so that u=f( k ₁ e, k ₂ ẋ, k ₃ ẍ ) applies.

The valve arrangement 1 also includes the electrically actuated switching valve 18. The switching valve 18 can be switched via the switching magnet 19 against the spring load by the mechanical return spring 20 and connects the vent connection 21 of the 3/3-way proportional valve 11 in its switching state with the vent outlet 15 and blocks the venting outlet 21 in its de-energized starting and resting position ("normal closed" = NC). In normal operation, the switching valve 18 is switched open via the microcontroller 16. In the event of a power failure, the switching valve 18 blocks automatically and thus prevents the venting of the 3/3-way proportional valve 11 and thus also of the entire system (including the air spring bellows 6 and 6' and the compressed air source 14, which can also be an intermediate pressure accumulator, for example ).

Finally, the valve arrangement 1 comprises the mechanically actuatable shut-off valve 22. This valve is closed in its resting state, but switches to an open position via mechanical actuation via the lever 3 from a lever position representing a specific stroke h, whereby the connecting line 10 is connected to the vent outlet 15 connects.

The microcontroller 16 is designed with a data communication interface 23 . The data communication point 23 is used for the data connection with a higher-level train control (in 2 not shown) via the data communication line 24. The data communication interface 23 can be used as a fieldbus interface (e.g. compatible with Profibus, DeviceNet/ControlNet or CANopen) or as an Industrial Ethernet interface (e.g. compatible with Profinet, EtherNet/IP, Ethernet Powerlink or EtherCat) configured. It can be designed to be compatible with several protocol standards at the same time. The microcontroller 16 can be integrated into a higher-level train control via the data communication interface 23, for example by the parameterization or setting of the dynamics of the control function or the filtering for the program-technical setup of the microcontroller 16 being selectable, specifiable or adjustable by the higher-level train control. Conversely, the microcontroller 16 can also be programmed to report process values to the higher-level train control, such as the actual distance.

The control behavior of an exemplary linear control function for determining the manipulated variable by the correspondingly programmed microcontroller 16 is in 3 shown as characteristic surface 25. In this case, the characteristic surface 25 represents the control space for the manipulated variable values u as a function of determined control deviation values e as a proportional element and car body travel speed values ẋ (dx) as a differential element of the exemplary linear control function.

Reference List

1

valve assembly

2

car body

3

lever

4

measuring linkage

5

Chassis & frame

6, 6'

air bag

7

primary suspension

8th

wheel axle

9.9'

wheel

10

connection line

11

3/3-way proportional valve

12

proportional solenoid

13.20

return spring

14

compressed air source

15

vent outlet

16

microcontroller

17

angle sensor

18

switching valve

19

shift magnet

21

vent port

22

shut-off valve

23

data communication interface

24

data communication line

25

characteristic surface

Claims (16)

1. Valve arrangement (1) for controlling the air suspension level of a rail vehicle, comprising a proportional directional control valve, a sensor means for continuously detecting a distance variable representing the distance between a car body (2) and a chassis or bogie of the rail vehicle, and a digital control device, characterized in that the control device is programmed to determine a control deviation on the basis of the actual distance detected by the sensor means and a comparison with a specifiable target distance, and to continuously generate manipulated variables as a linear function of the determined control deviation and the car body travel speed.
2. Valve arrangement (1) according to claim 1, characterized in that the car body travel acceleration is included as an additional control parameter of the linear function.
3. Valve arrangement (1) according to either claim 1 or claim 2, characterized in that the dynamics of the control function can be selected, specified or adjusted by modified parameterization of individual control parameters or by setting a modification factor for the control action, the manipulated variable or the actual distance.
4. Valve arrangement (1) according to any of claims 1 to 3, characterized in that the dynamics of the control function can be selected, specified or adjusted by intensity-related and/or time-related filtering of the actual distance or the control deviation.
5. Valve arrangement (1) according to either claim 3 or claim 4, characterized in that the dynamics of the control functions or the filtering can be selected, specified or adjusted on the basis of the operating mode or the travel speed of the rail vehicle.
6. Valve arrangement (1) according to any of claims 1 to 5, characterized in that the proportional directional valve is a 3-way proportional valve which has a venting position and an acting position, each with continuously variable opening cross sections, and a blocking position.
7. Valve arrangement (1) according to any of claims 1 to 6, characterized in that the proportional directional valve or the 3-way proportional valve assumes a venting position in the de-energized state and an electronically controllable switching means is arranged downstream of its venting connection, which switching means has a blocking position in the de-energized state and assumes an open position in the actuating position.
8. Valve arrangement (1) according to any of claims 1 to 7, characterized in that a working connection of the proportional directional valve or of the 3-way proportional valve is connected via a connecting line to a combined acting/venting connection of at least one air suspension device, and arranged together with the connecting line is a switching means, which can be mechanically actuated via a lever and a measuring linkage connected to the car body and the chassis, and which in its rest position assumes a blocking position, and which is switched from a lever position representing a definable actual distance into an open position, the switching means connecting the connecting line to a venting outlet.
9. Valve arrangement (1) according to any of claims 1 to 8, characterized in that the control device has at least one data communication interface which is compatible with at least one industrial protocol standard.
10. Valve arrangement (1) according to any of claims 3 to 5 and claim 9, characterized in that the control device is programmed to parameterize or to select, specify or adjust the dynamics of the control function or the filtering via the data communication interface.
11. Valve arrangement (1) according to either claim 9 or claim 10, characterized in that the proportional directional valve or the 3-way proportional valve has a sensor means for detecting the valve outlet pressure and the control device is programmed to determine a definable pressure drop and to generate an error signal and to transmit the signal via the data communication interface.
12. Method for controlling the air suspension level of a rail vehicle by means of a proportional directional control valve, a sensor means for continuously detecting a distance variable representing the distance between the car body (2) and a chassis or bogie, and a digital control device, characterized in that by means of the control device a control deviation is determined on the basis of a comparison of the actual distances detected by the sensor means with a specifiable target distance and a manipulated variable is continuously generated as a linear function of the determined control deviation and the car body travel speed.
13. Method according to claim 12, characterized in that the car body travel acceleration is included as an additional control parameter of the linear function.
14. Method according to either claim 12 or claim 13, characterized in that the dynamics of the control function can be selected, specified or adjusted by modified parameterization of individual control parameters or by setting a modification factor for the control action, the manipulated variable or the actual distance.
15. Method according to any of claims 12 to 14, characterized in that the dynamics of the control function can be selected, specified or adjusted by intensity-related and/or time-related filtering of the actual distance or the control deviation.
16. Method according to either claim 14 or claim 15, characterized in that the dynamics of the control functions and/or the filtering can be selected, specified or adjusted on the basis of the operating mode or the traveling speed of the rail vehicle.

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