Method for controlling vehicle seat valves

Abstract

This invention relates to a method for operating a vehicle seat valve, wherein the piston of the vehicle seat valve moves from a closed position to an open position or vice versa by applying voltage to a drive mechanism, particularly an electromagnetic drive mechanism. The power of the drive mechanism is adjusted via an effective voltage that can be varied by pulse width modulation of a pulse voltage having a constant frequency. To move the piston from its closed position toward its open position, the duty cycle of the pulse width modulation is first increased from a resting duty cycle, particularly 0%, to an initial duty cycle of less than 100%, particularly less than 50%, and then increased to a final duty cycle, particularly to 100%, after the piston reaches the open position and / or upon detection of an obstruction preventing the piston from moving before reaching its open position.

Description

Technical Field

[0001] This invention relates to a method for operating a vehicle seat valve. The invention also relates to a controller for implementing the method for at least one vehicle seat valve, and a vehicle seat having at least one vehicle seat valve and such a controller. Background Technology

[0002] In particular, seats installed in vehicles sometimes have at least one functional device that can be operated by fluid pressure. These functional devices range from their ergonomic adaptability to massage functions. In addition to electric actuators, hydraulically or pneumatically operated inflators are used for this purpose. Such inflators, also known as "airbags," include at least one cavity that is as fluid-sealed as possible, and mechanical work is caused by its volume changes based on filling and emptying.

[0003] The compressor used to establish the necessary fluid pressure can be placed, for example, inside or outside the vehicle seat, to achieve very low-noise operation of the expander. Its supply is mostly via hoses connected to the compressor in a fluid-guiding manner. Each hose is equipped with at least one vehicle seat valve, through which the targeted filling and evacuation of the corresponding expander can be controlled, for example. As the number of expanders increases, the number of vehicle seat valves required for operation increases accordingly. For this purpose, such vehicle seat valves can be combined into units in the form of valve bodies. Regarding the construction of such vehicle seat valves, a vehicle seat valve with a linearly movable piston is typically used.

[0004] DE102013225690A2 discloses a vehicle seat in which a backrest component hinged to a seat portion has multiple pneumatic inflators. These inflators can be filled with compressed air by a compressor, wherein the introduction and export of compressed air are controlled by a vehicle seat valve disposed between the compressor and the inflators in a fluid-guiding manner. These vehicle seat valves, configured as solenoid valves, have corresponding electromagnetic actuation mechanisms, which can be controlled by a controller connected thereto.

[0005] Typically, the drive mechanism of a vehicle seat valve is energized, causing the piston that cuts off or enables fluid flow to move linearly from a closed position to an open position, and / or vice versa. In practical applications, this can sometimes generate noticeable switching noise, particularly from the piston, accelerated by its drive mechanism, abutting against a motion limiter on its structure. Summary of the Invention

[0006] In this context, the objective of the present invention is to further develop a method for operating this type of vehicle seat valve, such that the switching noise of the vehicle seat valve is minimized at least during normal operation.

[0007] According to the present invention, the solution to the task lies in a method having measures according to the present invention. Furthermore, the task is solved by a controller according to the present invention for implementing the method according to the present invention, and by a vehicle seat having features according to the present invention.

[0008] Now, regarding the method proposed according to the invention, the power of the drive mechanism is adjusted via an effective voltage that can be changed by pulse width modulation (PWM). Specifically, a pulse voltage with a constant frequency forms the output basis, wherein the effective voltage ultimately applied to the drive mechanism of the vehicle seat valve is changed to a corresponding desired value only by manipulating the duty cycle of the pulse width modulation of the pulse voltage.

[0009] In other words, the pulse voltage, existing as a DC voltage, is periodically switched on and off within its frequency range, wherein the duration of each on-off cycle is obtained by dividing 1 second by a preset frequency in Hertz (Hz) (cycle duration = 1 / frequency [Hz]). The duty cycle refers to the ratio of the final pulse duration (on) to the cycle duration; for example, a 50% duty cycle changes the cycle duration of the pulse voltage to an effective voltage with pulse duration (on) and interval (off) of equal length. Starting with a cycle duration of 3.0 milliseconds (ms) as a simple example, the pulse duration and interval are each 1.5 ms. Furthermore, as a simple example, a 12-volt (V) pulse voltage can be changed to 6V by pulse width modulation with a 50% duty cycle. For example, a 75% duty cycle will change the pulse voltage from 12V to 9V, while a 25% duty cycle will achieve a change from 12V to 3V. In this way, the power of the drive mechanism can be adjusted solely by pulse width modulation of the pulse voltage and the resulting effective voltage applied to the drive mechanism, even by setting a 0% duty cycle up to 0V.

[0010] To move the piston from its closed position to its open position, the pulse width modulation duty cycle is first increased from the rest duty cycle to an initial duty cycle of less than 100%, preferably less than 50%. In this way, the actuation mechanism of the vehicle seat valve is initially supplied with an effective voltage lower than the pulse voltage, thus reducing its power accordingly. Only after the piston reaches the open position is the rest duty cycle increased to the final duty cycle, which is preferably 100%. Therefore, the actuation mechanism utilizes its full power only after the piston reaches the open position. Alternatively or supplementarily, if an obstruction hindering piston movement is identified before the piston reaches its open position, the rest duty cycle can be increased to the final duty cycle.

[0011] The resulting advantage is significantly lower noise operation of the vehicle seat valve. This is essentially due to the reduced power of its drive mechanism as the piston begins to move toward its open position, preventing the drive mechanism from striking the movement restriction parts of its structure with maximum force.

[0012] Here, for example, the duty cycle is increased to the final duty cycle only after a defined time period following the increase from the initial static duty cycle, after which the piston is typically expected to reach its open position. At this point, the piston is already against the area of ​​its motion restriction, so increasing to the final duty cycle only causes the piston to exert a similarly increased clamping force in the motion restriction area, thereby generating absolutely no mechanical noise. This also ensures that, regardless of overcoming any imperceptible movement blockage of the piston caused by factors such as temperature and / or other influences, the initial duty cycle cannot generate a sufficiently high starting force for the drive mechanism. Although this would generate corresponding noise from the piston moving with a correspondingly higher power or acceleration when impacting the motion restriction on the piston structure, this ensures the continued function of the vehicle seat valve outside of normal operation without such blockage.

[0013] If at least one device is available for identifying piston movement blockage, the initial duty cycle can be increased to the final duty cycle, or at least toward the final duty cycle, at the moment the piston movement blockage is identified. In practice, the identification device can utilize movement blockage during the increase of the initial duty cycle to monitor the success of this measure, thereby stopping further increase of the initial duty cycle toward the final duty cycle, for example, if the blockage has been identified as resolved, in order to largely minimize noise generation from the piston, which would otherwise be moving with increased efficiency and thus resting against its movement limit.

[0014] According to a particularly preferred further improvement of the basic inventive concept described above, the initial duty cycle can be linearly increased to an intermediate duty cycle. Here, the intermediate duty cycle lies between the initial duty cycle and the final duty cycle and is, in this respect, less than the final duty cycle. The initial duty cycle is linearly increased to the intermediate duty cycle within a first time period, which may end after or before the moment the piston reaches its open position while in motion. Therefore, this increase can be implemented while the piston is still moving or after the piston has reached its open position. Of course, the moment the piston reaches its open position can also fall within the time period during which the initial duty cycle is increased to the intermediate duty cycle, thus the increase begins before the piston reaches its open position and ends after it reaches the open position.

[0015] Based on this, the intermediate duty cycle can therefore be linearly increased to the final duty cycle before or after reaching the piston's open position. This increase occurs during a second time period following the first. This second time period can be shorter than the first. By increasing the intermediate duty cycle to the final duty cycle, it is ensured that even if the intermediate duty cycle cannot generate sufficient power in the drive mechanism to provide the starting force required to overcome the blockage, the piston will still move into its open position relative to the possible blockage.

[0016] After the piston reaches its open position, the final duty cycle can be reduced to the holding duty cycle either directly or abruptly after a defined period of time. Since the piston is in its open position at the latest after the final duty cycle is reached, the excessive power of the drive mechanism at that moment can be reduced accordingly by decreasing the final duty cycle. Here, the holding duty cycle to be reduced can be chosen such that the piston remains in its open position under any circumstances. Typically, the piston moves into its open position against a restoring force, which can be generated, for example, at least partially by a mechanical spring mechanism. This restoring force is, for example, specifically used to move the piston back to its closed position when needed. In this context, the holding duty cycle is chosen such that the piston continues to remain in its previously occupied open position even when subjected to a restoring force. In other words, ideally, a balance is achieved here between the effects of the interaction between the driving force exerted on the piston by the drive mechanism and the restoring force applied to the piston in the opposite direction, resulting in the piston remaining in its open position. Of course, the driving force of the drive mechanism can be slightly greater than the reset force, for example, 2% to 10% greater, so as to ensure the piston is in its open position under any circumstances (for example, also under temporary, effects and / or events affecting the piston position).

[0017] The vehicle seat valve is used to switch fluid flow, preferably compressed air. This means that fluid flow can occur when the vehicle seat valve is open (piston open position) and is blocked in its closed state (piston closed position). In this respect, the vehicle seat valve, as a switching unit, only knows two states. The present invention specifies that the fluid pressure of the fluid flow that can be switched through the vehicle seat valve can be detected. In particular, when fluid pressure downstream of the piston is detected, the state of the piston in its closed and / or open positions can be described. Therefore, an increase in the detected fluid pressure can, for example, indicate that the piston is on its path to or has reached its open position. Within the scope of the method according to the invention, an obstruction preventing the piston from moving toward its open position can therefore be identified, for example, based on the disappearance of a anticipated change in fluid pressure during operation of the drive mechanism.

[0018] Regarding the piston's rearward movement from its open position to its closed position, the present invention proposes additional measures to enable these measures to be implemented with the lowest possible noise:

[0019] Therefore, the piston can preferably first overcome the restoring force to move from its closed position toward its open position. The restoring force can be generated at least partially by a mechanical spring mechanism. Now, in order for the piston to move back from its open position toward its closed position, the duty cycle can be reduced to such an extent as it begins to move backward, until the driving force exerted on the piston by the drive mechanism is less than the restoring force applied to the piston in the opposite direction. By maintaining the reduction in duty cycle and the accompanying reduction in the driving force of the drive mechanism, the restoring force applied to the piston becomes sufficient from a certain value to make the piston move back from its open position toward its closed position. Because the piston does not accelerate at full power of the drive mechanism, the energy generated by the piston when it reaches the closed position in the area of ​​its motion limitation is correspondingly less, thereby significantly reducing noise generation.

[0020] It is conceivable that the fluid pressure acting on the piston as it is lifted from its open position increases the restoring force that would otherwise be loading the piston. Therefore, within the scope of this invention, it is specified that the fluid pressure increasing the restoring force during the piston's return movement toward its closed position can be detected, wherein the duty cycle is thus reduced to such an extent that the driving force acting on the piston by the drive mechanism is less than the restoring force increased by the fluid pressure when the piston is loaded in the opposite direction. In other words, measures to further refine the method according to the invention also take into account the possible influence of fluid pressure on the piston, so that the low-noise return of the piston to its closed position will keep the duty cycle reduced to a value that is as practical as possible and, in this respect, ideal.

[0021] Preferably, the reduction of the duty cycle back to the stationary duty cycle can be performed linearly. This means that the duty cycle is reduced constantly over, for example, a predetermined time period. Here, the reduction is carried out in such a way that the stationary duty cycle is reached once the piston is in its closed position. Alternatively, the reduction can be carried out such that the stationary duty cycle is only reached after the piston is in its closed position. This ensures that the piston never moves back to its closed position with the full height of the restoring force, which would otherwise cause corresponding noise upon reaching the movement restriction in its structure.

[0022] The method according to the invention provides a very simple way to influence the movement of a piston in a vehicle seat valve in such a way that generally perceptible noise is significantly reduced or even completely avoided. By adjusting the duty cycle of the pulse width modulation of the pulse voltage, the force acting on the piston and causing it to move can be kept within a consistently suitable range that ensures piston movement but avoids moving the piston with excessively high driving forces. In addition to the potential noise reduction, this also results in a significant reduction in wear on the piston and / or its structural movement restraints.

[0023] Furthermore, the present invention relates to a controller for implementing the method according to the invention for at least one vehicle seat valve.

[0024] The present invention also relates to a vehicle seat having at least one vehicle seat valve and a controller according to the present invention.

[0025] The advantages obtained by the controller and / or vehicle seat according to the invention have been described in detail in conjunction with the method according to the invention, so as to avoid repetition here, see the corresponding embodiments. Attached Figure Description

[0026] The invention will now be described in detail with reference to the illustrative embodiments shown. In the accompanying drawings:

[0027] Figure 1 A schematic process illustrating the method according to the invention for moving a piston of a vehicle seat valve to its open position, and...

[0028] Figure 2 A schematic process is shown for a method according to the invention for moving a piston of a vehicle seat valve to its closed position. Detailed Implementation

[0029] Figure 1 This illustrates a simple schematic process according to the invention for moving a piston of a vehicle seat valve (not shown in detail). Here, by means of a first function... Figure 1a only illustrates the operation of the vehicle seat valve, thereby obtaining an effective voltage applied to the drive mechanism of the actuating piston. The drive mechanism is preferably an electromagnetic drive mechanism.

[0030] The method according to the invention is based on a pulsed voltage with a constant frequency, to which a correspondingly variable effective voltage can be applied to the drive mechanism via pulse width modulation (PWM). By varying the effective voltage, the power of the drive mechanism that actively moves the piston to its closed position can be adjusted accordingly. For this purpose, the duty cycle D of the pulse width modulation is changed in the manner described below:

[0031] When the piston begins to move, it is in its closed position. In the closed position, the piston is loaded and held in place by, for example, a mechanical spring mechanism. In the closed position, the resting duty cycle D1 is 0%, resulting in an effective voltage of 0.0 volts (V) applied to the drive mechanism. Now, in order to move the piston from its closed position to its open position, for example, after a time t of 20 milliseconds (ms), the resting duty cycle D1 is suddenly increased to the starting duty cycle D2. Here, the starting duty cycle D2 is examplely 30%, thus a pulse voltage of approximately 30% is now applied to the drive mechanism as an effective voltage.

[0032] The initial duty cycle D2 is chosen in principle such that the piston moves from its closed position toward its open position in the opposite direction to the restoring force applied to it during normal operation. An initial duty cycle D1 may already be sufficient to move the piston into its open position, as the piston reaches the open position with only a small speed and force due to the reduced power of the drive mechanism. As a result, especially with a correspondingly gentle contact with the motion restraints on its structure, the resulting noise generation is minimized.

[0033] To overcome the potential movement blockage of the piston, the initial duty cycle D2 is increased to an intermediate duty cycle D3 during the first time period T1 of 60 ms (purely illustrative in this case). Exemplarily, the intermediate duty cycle D3 is currently 60%, such that 60% of the pulse voltage is now applied to the drive mechanism as an effective voltage. In this respect, it is advantageous to linearly increase to the intermediate duty cycle D3 because the parallel increase in driving force of the drive mechanism, in the event of potential piston movement blockage, will at some point reach a level sufficient to overcome the blockage and thus move the piston to its open position. Simultaneously, only a portion of the maximum possible pulse voltage is applied to the drive mechanism as an effective voltage, thereby also producing potentially higher, but always very low, noise.

[0034] If there is no motion blockage, the piston, already in its open position due to the initial duty cycle D2, is only further pressed against the motion restriction part of its structure by this measure, thus generating absolutely no noise. In this regard, increasing the initial duty cycle D2 to the intermediate duty cycle D3 should be understood as a protective measure to ensure that the piston is not held in its closed position due to motion blockage.

[0035] To overcome the still significant motion blockage of the piston, which is either in its closed position or stuck on its path to the open position, the intermediate duty cycle D3 is now increased to the final duty cycle D4 during the second time period T2 (which is merely illustrative in this case) of 20 ms. As can be seen, the second time period T2 is significantly shorter than the first time period T1, thus, combined with the additional 40% increase in duty cycle D, the function during the second time period T2 is derived. Figure 1 The direction of a is significantly steeper.

[0036] By way of example only, the final duty cycle D4 is currently 100%, so that 100% of the pulse voltage is now applied as an effective voltage to the drive mechanism. In this respect, it is advantageous to linearly increase the final duty cycle D4 because the parallel increase in drive force of the drive mechanism will at some point reach a level sufficient to overcome the motion blockage and thus move the piston to its open position, in the event of a possible piston movement blockage. This also overcomes any potential movement blocks in the region of the piston's open position, allowing those blocks to eventually move to their open position. The piston speed and force generated by the significantly higher drive power of the drive mechanism can be accompanied by correspondingly greater noise generation in this scenario outside of normal operation, but this ensures that the piston moves to its open position under all circumstances.

[0037] Starting from the measures taken previously, the piston is now clearly in its open position. In the next step, the final duty cycle D4 is now abruptly reduced to a holding duty cycle D5. This holding duty cycle is, for example, 40%, so that 40% of the pulse voltage is now also applied to the drive mechanism as the effective voltage.

[0038] The duty cycle D5 is chosen in this way so that the piston is reliably held in its open position under any circumstances and the vehicle seat valve performs its intended function.

[0039] In principle, the fluid pressure acting on the piston can also be detected by the fluid flow that can be switched via the vehicle seat valve. As long as the duty cycle D used to introduce the piston out of its closed position is manipulated, but no expected change in fluid pressure is detected here, the first time period T1 can be shortened and / or the intermediate duty cycle D3 can be higher than the value shown here, for example, in order to overcome the apparent motion blockage of the piston as quickly as possible.

[0040] Figure 2 Using the second function in the same purely illustrative way Figure 1 b illustrates the process of a method according to the invention for repositioning the piston back to its closed position. As can be seen, the duty cycle D5 is initially, exemplarily, 40% in the open position of the piston. From there, the duty cycle D5 is maintained, exemplarily, reduced to the initial stationary duty cycle D1 of 0% after a third time period T3 following a 20 ms interval. Exemplarily, the third time period T3 is here 60 ms.

[0041] By applying a restoring force to the piston, at a certain point during the period when the duty cycle D5 is decreasing, the restoring force reaches a point greater than the current duty cycle D, thus allowing the piston to smoothly return to its closed position through the restoring force. Here, the third time period T3 is chosen such that, under normal circumstances, the restoring duty cycle D1 is reached either once the piston reaches its closed position or only after the piston has reached its closed position. In this way, the speed and force of the moving piston are further reduced to a minimum, resulting in a significant reduction in noise.

[0042] Of course, the fluid pressure that increases the restoring force of the loaded piston during its return movement toward its closed position can also be detected, and thus taken into account while maintaining the reduced duty cycle D5. This consideration can, for example, be expressed in a corresponding adaptation for the third time period T3.

[0043] List of reference numerals

[0044] 1a First function graph

[0045] 1b Second function graph

[0046] D is the duty cycle of pulse width modulation as a percentage.

[0047] D1 Static Duty Cycle

[0048] Duty cycle starts at D2

[0049] D3 intermediate duty cycle

[0050] D4 Final Duty Cycle

[0051] D5 maintains duty cycle

[0052] t is time in milliseconds [ms]

[0053] The first time period between T1D2 and D3

[0054] The second time period between T2D3 and D5

[0055] The third time period between T3D5 and D1

Claims

1. A method for operating a vehicle seat valve, wherein the piston of the vehicle seat valve is actively moved from a closed position to an open position or vice versa by applying voltage to a drive mechanism, characterized in that, The power of the drive mechanism is adjusted by means of an effective voltage that can be changed by pulse width modulation of a pulse voltage with a constant frequency. In order to move the piston from its closed position to its open position, the duty cycle (D) of the pulse width modulation is first increased from the rest duty cycle (D1) to an initial duty cycle (D2) of less than 100%, and then increased to the final duty cycle (D4) after the piston reaches the open position and / or when an obstruction preventing the piston from moving before reaching its open position is detected.

2. The method according to claim 1, characterized in that, The initial duty cycle (D2) is first linearly increased during the first time period (T1) to an intermediate duty cycle (D3) that is smaller than the final duty cycle (D4).

3. The method according to claim 2, characterized in that, The intermediate duty cycle (D3) is linearly increased to the final duty cycle (D4) during a second time period (T2) before or after the piston reaches the open position.

4. The method according to any one of claims 1 to 3, characterized in that, After the piston reaches the open position, the final duty cycle (D4) is reduced to the maintenance duty cycle (D5), so that the piston loaded with the reset force remains in its open position by the driving force of the reaction of the reset force by the drive mechanism.

5. The method according to any one of claims 1 to 3, characterized in that, The fluid pressure of the fluid flow that can be switched via the vehicle seat valve is detected, wherein the blockage preventing the piston from moving toward its open position is identified based on the disappearance of the expected change in fluid pressure during operation of the drive mechanism.

6. The method according to claim 4, characterized in that, The piston moves from its closed position toward its open position against the reset force, wherein, as the piston moves back from its open position toward its closed position, the holding duty cycle (D5) decreases to the extent that the driving force exerted on the piston by the drive mechanism is less than the reset force applied to the piston in the opposite direction.

7. The method according to claim 4, characterized in that, The fluid pressure that increases the reset force of the loaded piston during the piston's return movement toward its closed position is detected, wherein the holding duty cycle (D5) is reduced to such an extent that the driving force exerted on the piston by the drive mechanism is less than the reset force increased by the fluid pressure when the piston is loaded in the opposite direction.

8. The method according to claim 4, characterized in that, The duty cycle (D5) is linearly reduced to the stationary duty cycle (D1) such that the stationary duty cycle (D1) is reached either once the piston is in its closed position or after the piston is in its closed position.

9. The method according to claim 1, characterized in that, The driving mechanism is an electromagnetic driving mechanism.

10. The method according to claim 1, characterized in that, The static duty cycle (D1) is 0%.

11. The method according to claim 1, characterized in that, The initial duty cycle (D2) is less than 50%.

12. The method according to claim 1, characterized in that, The final duty cycle (D4) is 100%.

13. The method according to claim 1, characterized in that, The initial duty cycle (D2) is first linearly increased to an intermediate duty cycle (D3) that is smaller than the final duty cycle (D4) during a first time period (T1) before or after the piston reaches the open position.

14. The method according to claim 3, characterized in that, The second time period (T2) is shorter than the first time period (T1).

15. The method according to any one of claims 1 to 3, characterized in that, After the piston reaches the open position, the final duty cycle (D4) suddenly decreases to the maintenance duty cycle (D5), so that the piston loaded with the reset force remains in its open position due to the driving force of the reaction of the reset force by the drive mechanism.

16. The method according to claim 4, characterized in that, The restoring force is a restoring force caused by a mechanical spring mechanism.

17. The method according to claim 4, characterized in that, The piston moves from its closed position toward its open position against the restoring force caused by the mechanical spring mechanism, wherein, as the piston moves back from its open position toward its closed position, the holding duty cycle (D5) decreases to the extent that the driving force exerted on the piston by the drive mechanism is less than the restoring force applied to the piston in the opposite direction.

18. The method according to claim 4, characterized in that, During the piston's return movement toward its closed position or after reaching the closed position, the holding duty cycle (D5) linearly decreases to the resting duty cycle (D1), such that the resting duty cycle (D1) is reached either once the piston is in its closed position or after the piston is in its closed position.

19. A controller for implementing the method according to any one of claims 1 to 18 for at least one vehicle seat valve.

20. A vehicle seat having at least one vehicle seat valve and a controller according to claim 19.

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