Detection and prevention of a pinching event

Abstract

Device (1) for detecting a jamming event of a motor-operated locking system of a vehicle (2) - with a sensor electrode (3) which surrounds at least section by section an opening (O) of the vehicle (2) which can be closed by means of at least one closing element (4), wherein - the sensor electrode (3) is arranged in a sealing element (10) that at least partially surrounds the opening (O), characterized in that - a reference sensor electrode (15) is provided which surrounds the opening (O) of the vehicle (2) at least section by section on the side, - the reference sensor electrode (15) is arranged at a distance from the sensor electrode (3) in the sealing element (10) and has a greater distance to the opening (O) than the sensor electrode (3), - a control unit (5) is provided which is designed, - to apply an electrical potential to the sensor electrode (3) and the reference sensor electrode (15) respectively for a charging process and a ground potential (GND) for a discharging process, - to record the time period until a minimum threshold value of the electrical potential for the sensor electrode (3) and the reference sensor electrode (15) is reached, caused by a backflow of charges via the ground potential (GND), - to determine a difference between the time duration recorded for the sensor electrode (3) and the time duration recorded for the reference sensor electrode (15) and - then, if the difference exceeds a predetermined threshold and if the time period recorded for the sensor electrode (3) deviates from a predetermined standard time period or a standard time period recorded in a state without an imminent entrapment event, to conclude that an imminent entrapment event is imminent.

Description

[0001] The invention relates to a device for detecting a jamming event of a motor-operated locking system of a vehicle according to the preamble of claim 1.

[0002] The invention further relates to a method for operating such a device and a device for preventing a jamming event of a motor-operated locking system of a vehicle.

[0003] From DE 10 2020 002 817 A1, a device for preventing a pinching event in a motorized locking system of a vehicle is known. The device comprises a sensor electrode which surrounds at least a portion of the vehicle's opening, which can be closed by means of a locking element, at its periphery. The device further comprises a microcontroller, a measuring pin coupled to the microcontroller and the sensor electrode, and a control pin coupled to the microcontroller and, via a high-resistance electrical resistor, to the sensor electrode. The microcontroller is configured to apply an electrical potential to the sensor electrode via the control pin and simultaneously to measure the electrical potential of the sensor electrode and the distribution of negative charges on the sensor electrode at the measuring pin.As soon as the electrical potential measured at the sensor pin reaches a predefined threshold, the microcontroller applies an electrical ground potential to the control pin, causing charges to flow back from the sensor electrode. Furthermore, the microcontroller is configured to detect the time interval from reaching the threshold until a minimum threshold value of the electrical potential is reached (due to the charge flow back), and if the detected time interval deviates from a predefined interval or from a standard interval recorded in a state without an imminent clamping event, it infers that a clamping event is imminent.

[0004] Furthermore, DE 10 2004 002 415 A1 discloses a device for controlling and monitoring an electrically driven window pane of a motor vehicle that can be moved between an open and a closed position. The device comprises a sensor that includes a sensor electrode which generates an electric field in an opening area of ​​the locking element. The device further comprises a control unit connected to the sensor that detects a change in the capacitance of the sensor electrode and provides a control signal, wherein the control unit detects a capacitive change of the sensor electrode due to the presence of a layer of moisture on the locking element.

[0005] EP 1 154 110 A2 describes an anti-pinch device for detecting the presence of an object in a scanning area. The anti-pinch device comprises a body section, a ground electrode embedded in the body section, and a sensor electrode spaced apart from the ground electrode and embedded in the body section. The sensor electrode and the ground electrode are charged to different electrical potentials. The body section is made of an electrically non-conductive material to insulate the sensor electrode from the ground electrode. The anti-pinch device further comprises a reduced-stiffness zone located between the ground electrode and the sensor electrode, the reduced-stiffness zone being located within the body section and co-extruded with it.Furthermore, the zone of reduced stiffness is provided in the form of an air gap within the body section or in the form of a material with higher elasticity than that of the body section, wherein the material with higher elasticity is made of foam rubber. The body section comprises an electrically conductive area surrounding the sensor electrode and an electrically conductive area surrounding the ground electrode. Additionally, the pinch protection includes a device for generating input signals applied to the sensor electrode and for receiving output signals from the sensor electrode.The device is capable of receiving both output signals, wherein the output signals change depending on a change in capacitance between the sensor electrode and the ground electrode in the case of the presence of a dielectric object in the scanning area, and the output signals change depending on a change in capacitance between the sensor electrode and the ground electrode in the case of the presence of a non-conductive object due to a change in the relative position of the sensor electrode and the ground electrode.

[0006] The invention is based on the objective of providing a device for detecting an entrapment event of a motor-operated locking system of a vehicle that is improved compared to the prior art, an improved method for operating such a device and an improved device for preventing an entrapment event of a motor-operated locking system of a vehicle.

[0007] The problem is solved according to the invention by - a device for detecting a jamming event of a motor-operated locking system of a vehicle, which has the features specified in claim 1, - a method which has the features specified in claim 9, and - by a device for preventing a jamming event of a motor-operated locking system of a vehicle, which has the features specified in claim 10.

[0008] Advantageous embodiments of the invention are the subject of the dependent claims.

[0009] A device for detecting a pinching event in a motorized locking system of a vehicle comprises a sensor electrode which surrounds at least a portion of the vehicle's opening, which can be closed by means of at least one locking element. The sensor electrode is arranged in a sealing element that at least partially surrounds the opening.

[0010] According to the invention, a reference sensor electrode is provided which surrounds the opening of the vehicle at least partially at its edge, wherein the reference sensor electrode is arranged in the sealing element at a distance from the sensor electrode and has a greater distance to the opening than the sensor electrode. Furthermore, a control unit is provided which is configured to apply an electrical potential to the sensor electrode and the reference sensor electrode, respectively, for a charging process and a ground potential, respectively, for a discharging process, and to measure the time period until a minimum threshold value of the electrical potential for the sensor electrode and the reference sensor electrode is reached, caused by a backflow of charges via the ground potential.The control unit is further designed to determine a difference between the time recorded for the sensor electrode and the time recorded for the reference sensor electrode, and then, if the difference exceeds a predetermined threshold and if the time recorded for the sensor electrode deviates from a predetermined standard time or a standard time recorded in a state without an imminent pinching event, to conclude that a pinching event is imminent.

[0011] The device is intended, for example, for use in a vehicle to detect a pinching event between the locking element and a vehicle structure that at least partially surrounds the locking element at its edges. This could include, for example, a motor-operated window pane and a vehicle structure that at least partially surrounds a window opening at its edges, or a motor-operated vehicle door and a vehicle structure that at least partially surrounds the vehicle door at its edges.

[0012] Safety requirements for so-called window regulator anti-pinch protection in vehicles demand a high level of responsiveness, which cannot be guaranteed by, for example, a known current-based anti-pinch system. This is primarily due to the relatively high stiffness of the test object used to test the anti-pinch protection, which is 65 N / mm. The test object represents, for example, the characteristics of a child's finger. Furthermore, the responsiveness of known anti-pinch systems is severely limited by a system time constant, which describes the time it takes for a window regulator motor to be controlled and the window pane to react. With frameless vehicle doors, a particular challenge is that guiding the window pane in the upper block cannot be ensured by freely positionable test object angles and angles. This also applies to door anti-pinch systems.

[0013] In contrast, the device according to the invention enables preventive anti-pinch protection, allowing a reaction without the occurrence of a pinching force. This means that objects and body parts in a window frame or door opening and in a critical pinch zone, for example near the seal, can be detected before a pinching force occurs. Thus, the future safety requirement FMVSS-118 can be met. The device can be manufactured with particularly low material and cost expenditure. Detection is contactless and non-contact, and the device is exceptionally robust. The detection range is, for example, 0.5 cm to 5 cm.In particular, increased robustness compared to capacitive systems is achieved through continuous recalibration of the discharge time, i.e., the time it takes to reach the minimum threshold of the electrical potential caused by the backflow of charges. This results in very high robustness against moisture and system changes. Furthermore, robustness is achieved through possible synchronization with the position of a window pane, thus enabling the anti-pinch protection to be activated only in critical areas. It is also not necessary for an object that could be trapped to be connected to ground potential.

[0014] In devices using only one active sensor electrode, environmental properties forming a baseline are determined by the same sensor electrode as a slow low-pass filter. A fast low-pass filter is then derived from this same filter to calculate a difference value. This makes it impossible to distinguish whether changes are local to the clamping area or global, caused, for example, by external electric and magnetic fields. To avoid false detection, a high threshold must be set and exceeded during the measurement performed with the sensor electrode, resulting in low sensitivity. Interactions between the sensor electrode and the charge distribution of a vehicle body further reduce the potential sensitivity, as stronger field interactions can occur than those caused by the clamping object itself.Objects trapped within the entrapment zone cannot be detected due to the continuous adaptation of the baseline to the prevailing state. In contrast, the present device, by using a reference sensor electrode to determine environmental properties and thus establishing a robust baseline, allows for the use of lower threshold values ​​while maintaining high robustness against false detections. This enables the device to react to smaller differential values, resulting advantageously in increased sensitivity, reduced inertia in detecting an entrapment event, and a decrease in the number of false detections.A distinction can also be made between local interactions in the clamping area, which primarily affect one of the electrodes, and interactions caused by external influences that affect both electrodes, such as interactions of the sensor electrode with the charge distribution of the vehicle body and external electric and magnetic fields. This means that it is possible to differentiate between local and global events.

[0015] In one possible embodiment of the device, the control unit is further configured to periodically stagger the charging and discharging processes for the sensor electrode and the reference sensor electrode such that the charging and discharging process of the sensor electrode starts after the charging and discharging process of the reference sensor electrode is complete, or vice versa. Thus, one of the two electrodes is always inactive, effectively and easily preventing mutual interference between the electrodes during measurement.

[0016] In another possible embodiment of the device, the sensor electrode is arranged in an inner sealing lip of the sealing element, and the reference sensor electrode is arranged in an outer sealing lip of the sealing element. This allows for simple and protected integration of the two electrodes, with the reference sensor electrode being located near the sensor electrode but not directly facing or located within the clamping area.

[0017] In another possible embodiment of the device, the control unit and the sensor electrode are coupled to a first measuring pin, and the control unit and the reference sensor electrode are coupled to a second measuring pin. Furthermore, the control unit and the sensor electrode are coupled to the first control pin via a high-resistance electrical resistor, and the control unit and the reference sensor electrode are coupled to the second control pin via a high-resistance electrical resistor.The control unit is designed to apply the respective electrical potential to the sensor electrode and the reference sensor electrode via the first control pin and the second control pin, to simultaneously measure the electrical potential of the sensor electrode and a distribution of negative charges on the sensor electrode at the first measuring pin, and to simultaneously measure the electrical potential of the reference sensor electrode and a distribution of negative charges on the reference sensor electrode at the second measuring pin.Furthermore, the control unit is designed to apply the electrical ground potential to the control pins as soon as the electrical potentials measured at the measuring pins reach a predefined threshold value, causing the charges to flow back from the sensor electrode and the reference sensor electrode. The unit also records the respective time interval from reaching the threshold value until the minimum threshold value of the electrical potential for the sensor electrode and the reference sensor electrode is reached, as caused by the charge flow back. This design is characterized by its simple construction, reliable operation, and high robustness against disturbances, and can be implemented with minimal material and cost expenditure.

[0018] In another possible embodiment of the device, the sensor electrode and the reference sensor electrode are each coupled to the ground potential via an electrical capacitor.

[0019] In another possible embodiment of the device, the sensor electrode and the reference sensor electrode are designed as sensor cables with an electrical conductor and surrounding electrical insulation. This allows for a particularly simple, durable, and cost-effective design of the sensor electrode and reference sensor electrode. Furthermore, it enables easy integration of both electrodes into the sealing element.

[0020] In another possible embodiment of the device, a shielding electrode is arranged in a vehicle frame element or roof rail that at least partially surrounds the opening, protecting the sensor electrode and the reference sensor electrode from interference. The shielding electrode provides protection against interference occurring on a side facing away from the measuring area, thereby rendering the device insensitive to interference. By arranging the shielding electrode in the vehicle frame element or roof rail, reliable operation of the shielding electrode is ensured, and simple integration into a vehicle is possible.

[0021] In another possible embodiment of the device, the control unit is further configured to detect an imminent entrapment event if, during the activated closing movement of the locking element, it is determined that the locking element is located in a predefined critical area. This prevents false activations of the anti-pinch protection, particularly when an object capable of being trapped is moved from an area between the locking element and the surrounding vehicle structure during the closing movement of the locking element.

[0022] In the inventive method for operating the aforementioned device, the electrical potential is applied to the sensor electrode and the reference sensor electrode, respectively, for the charging process and for the discharging process. The time until a minimum threshold value of the electrical potential is reached for both the sensor electrode and the reference sensor electrode is recorded. This threshold value is then determined. Furthermore, a difference is calculated between the time recorded for the sensor electrode and the time recorded for the reference sensor electrode. If this difference exceeds a predetermined threshold value, and if the time recorded for the sensor electrode deviates from a predetermined standard time or from a standard time recorded in a state without an imminent clamping event, an imminent clamping event is inferred.

[0023] Due to the use of a reference sensor electrode to determine environmental properties and the resulting robust baseline, this method allows for the use of lower threshold values ​​while simultaneously achieving high robustness against false detections. This enables responses to smaller differential values, advantageously leading to increased sensitivity, reduced inertia in detecting a pinching event, and a decrease in the number of false detections. Furthermore, the method can differentiate between local interactions within the pinching area, which primarily affect one of the electrodes, and interactions caused by external influences that affect both electrodes, such as interactions between the sensor electrode and the charge distribution of the vehicle body, as well as external electric and magnetic fields. In other words, it is possible to distinguish between local and global events.

[0024] The device according to the invention for preventing a jamming event in a motorized locking system of a vehicle comprises a previously mentioned device for detecting a jamming event and at least one control unit for controlling a motor drive of the locking element, wherein the control unit is configured to stop and / or reverse a closing movement of the locking element when a jamming event is imminent. The device enables particularly reliable prevention of jamming events while simultaneously minimizing false detections and false triggering.

[0025] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0026] This shows: Fig. 1. Schematic electrical circuit diagram of a device for detecting a jamming event in a motor-operated locking system of a vehicle, Fig. 2 schematically a section of a side view of a vehicle, Fig. 3. Schematically, a perspective view of a sectional representation of a section of the vehicle according to Fig. 2 in the area of ​​a vehicle structure and a sealing element, Fig. 4 schematically a perspective view of a sectional representation of a section of a vehicle door in the area of ​​a sealing element, Fig. 5 schematically a flowchart of a possible embodiment of a method for detecting a jamming event of a motor-operated locking system of a vehicle, Fig. 6 schematically a flowchart of a possible embodiment of a method for preventing a jamming event of a motor-operated locking system of a vehicle and Fig. 7 schematically a vehicle door with a window opening and a window pane.

[0027] Corresponding parts are marked with the same reference symbols in all figures.

[0028] In Fig. Figure 1 is an electrical circuit diagram of a possible embodiment of a device 1 for detecting a jamming event of a motor-operated locking system of a [unclear] Fig. Vehicle 2 is shown in more detail.

[0029] The device 1 comprises a sensor electrode 3, which is connected by means of at least one closure element 4 (shown in Fig. 7) closable opening O (shown in Fig. 2) surrounds the vehicle 2 at least partially along its outer edge. The sensor electrode 3, for example, has a length of more than 0.1 m up to 5 m.

[0030] The device 1 further comprises a reference sensor electrode 15, which also surrounds the closable opening O of the vehicle 2 at least partially along its edge. The reference sensor electrode 15 is arranged at a greater distance from the opening O than the sensor electrode 3.

[0031] The sensor electrode 3 and the reference sensor electrode 15 are together in a housing that at least partially surrounds the opening O and is located in the Fig. 2 to 5 sealing element 10 shown in more detail.

[0032] The device 1 further comprises a control unit 5, for example a microcontroller, a measuring pin 6 coupled to the control unit 5 and the sensor electrode 3, and a control pin 8 coupled to the control unit 5 and to the sensor electrode 3 via a high-impedance electrical resistor 7.

[0033] Furthermore, the device 1 comprises a measuring pin 16 coupled to the control unit 5 and the reference sensor electrode 15, and a control pin 18 coupled to the control unit 5 and to the reference sensor electrode 15 via a high-impedance electrical resistor 17.

[0034] The sensor electrode 3 and the reference sensor electrode 15 can each be coupled to the ground potential GND of the vehicle 2 via an electrical capacitor 9, 19. In embodiments not shown in detail, the capacitors 9, 19 can be omitted.

[0035] The sensor electrode 3 and the reference sensor electrode 15 are each configured as sensor cables with an electrical conductor 3.1, 15.1 and surrounding electrical insulation 3.2, 15.2. The electrical conductors 3.1, 15.1 are, for example, copper conductors, and the electrical insulations 3.2, 15.2 are, for example, plastic or rubber insulation. The sensor cables each have a diameter of, for example, 0.5 mm to 2 mm. In particular, the sensor electrode 3 and the reference sensor electrode 15 are identical to each other to facilitate comparability of the measured results.

[0036] The control unit 5 is configured to apply an electrical potential to the sensor electrode 3 via control pin 8 and simultaneously measure the electrical potential of the sensor electrode 3 and the resulting distribution of negative charges on the sensor electrode 3 at measuring pin 6. As soon as the electrical potential measured at measuring pin 6 reaches a predefined threshold value, the control unit 5 applies the electrical ground potential (GND) to control pin 8, causing negative and positive charges to flow back from the sensor electrode 3. The control unit 5 records the time period from when the threshold value is reached until a minimum threshold value of the electrical potential is reached, caused by the return flow of charges.

[0037] Furthermore, the control unit 5 is configured, analogous to the procedure at the sensor electrode 3, to apply an electrical potential to the reference sensor electrode 15 via control pin 18 and simultaneously to measure the electrical potential of the reference sensor electrode 15 and the resulting distribution of negative charges on the reference sensor electrode 15 at measuring pin 16. As soon as the electrical potential measured at measuring pin 16 reaches a predetermined threshold value, the control unit 5 applies the electrical ground potential (GND) to control pin 18, causing negative and positive charges to flow back from the reference sensor electrode 15. Here, too, the control unit 5 records the time period from reaching the threshold value until a minimum threshold value of the electrical potential is reached, caused by the backflow of charges.

[0038] Here, environmental properties are determined using the reference sensor electrode 15, from which a so-called baseline is established. This baseline represents external global conditions, i.e., influences that act on both the sensor electrode 3 and the reference sensor electrode 15. These influences include, for example, interactions of the sensor electrode 3 and the reference sensor electrode 15 with the charge distribution of a vehicle body, external charge distributions, external electric and magnetic fields, etc. It is specifically assumed that an external global change occurs significantly more slowly than the cycle times used, for example, approximately 50 µs.

[0039] The charging and discharging processes for sensor electrode 3 and reference sensor electrode 15 are periodically staggered such that the charging and discharging process for sensor electrode 3 starts after the charging and discharging process for reference sensor electrode 15 is complete, or vice versa. This means that one of the two electrodes is always inactive, thus preventing mutual interference between the electrodes.

[0040] Furthermore, a difference is determined between the time recorded for sensor electrode 3 and the time recorded for reference sensor electrode 15. If the difference exceeds a predefined threshold and the time recorded for sensor electrode 3 deviates from a predefined standard time or from a standard time recorded in a state without an imminent entrapment event, the control unit 5 concludes that an imminent entrapment event is occurring.

[0041] This deviation from the standard duration results from the fact that negative charges are immobilized in the sensor electrode 3 by an external influence of an object, for example a human extremity, and thus prevented from flowing back, consequently causing inhomogeneities in a charge distribution within the sensor electrode 3.

[0042] By comparing the measured values ​​acquired by sensor electrode 3 with the baseline, differences of local origin, such as the approach of body parts, can be reliably determined. This enables high robustness and more stable detection of local, inert effects (> 50 ms). Calibration of sensor electrode 3 to the environment using slow low-pass filters is not required.

[0043] Fig. Figure 2 shows a section of a side view of a vehicle 2, which includes frameless vehicle doors (not shown). In such vehicle doors, sealing elements 4, designed as window panes, are sealed by means of at least one sealing element 10 that at least partially surrounds the opening O, in this case a window opening, at its edge, both when the vehicle door is closed and when the window pane is closed. In the illustrated embodiment, the sealing element 10 is arranged on a vehicle structure 11 formed by a roof beam.

[0044] In Fig. Figure 3 is a perspective view of a sectional representation of a section of vehicle 2 according to Fig. Figure 2 shows the area of ​​the vehicle structure 11, which is designed as a roof beam, and the sealing element 10. The sealing element 10 is designed as a roof seal with a so-called bubble shape.

[0045] To prevent a pinching event between the window pane and the sealing element 10 by detecting an imminent pinching event according to the description to Fig. 1 The sensor electrode 3 is arranged in the sealing element 10 completely and directly surrounded by a sealing material 10.1 or alternatively in a cavity 10.2. The sensor electrode 3 is, in particular, arranged in an inner sealing lip of the sealing element 10.

[0046] Furthermore, the reference sensor electrode 15 is completely and directly surrounded by the sealing material 10.1 in the sealing element 10 or alternatively in the cavity 10.2 such that it has a greater distance to the opening O than the sensor electrode 3. In particular, the reference sensor electrode 15 is arranged in an outer sealing lip of the sealing element 10.

[0047] Furthermore, a shielding electrode 13 is arranged to shield the sensor electrode 3 and the reference sensor electrode 15 from interference occurring in the area of ​​the vehicle structure 11, which is designed as a roof pillar. Alternatively, the shielding electrode 13 can also be designed as a shielding cable with an electrical conductor, for example a copper conductor, and surrounding electrical insulation, for example a plastic or rubber insulation.

[0048] When using the shielding electrode 13, the sensor electrode 3 and the reference sensor electrode 15 are, for example, not coupled to the electrical ground potential GND via the capacitors 9, 19. The shielding electrode 13 is specifically coupled to the ground potential GND and is arranged, in particular, between the sensor electrode 3 and the edge of the opening O.

[0049] In the illustrated embodiment of device 1, the detection of an imminent entrapment event is carried out analogously to the detection described above. Fig. 1, wherein the shielding electrode 13 provides a directed, in particular downward-directed, measuring range and shielding against disturbances occurring on a side facing away from the measuring range. Thus, the device 1 is rendered insensitive to disturbances.

[0050] Fig. Figure 4 shows a perspective view of a sectional representation of a section of a vehicle door 12 in the area of ​​a sealing element 10, wherein the vehicle door 12 is designed as a so-called frame door, the frame of which forms the vehicle structure 11, on which a sealing element 10 is arranged for sealing the window pane when closed. The sealing element 10 is designed as a frame seal of the frame of the vehicle door 12.

[0051] To detect an entrapment event between the window pane and the sealing element 10 by detecting an imminent entrapment event according to the description to Fig. In the case of 1, a sensor electrode 3 and a reference sensor electrode 15 are arranged in the sealing element 10, completely and directly surrounded by the sealing material 10.1 or in the cavity 10.2. The reference sensor electrode 15 is arranged such that it has a greater distance to the opening O than the sensor electrode 3.

[0052] Furthermore, a shielding electrode 13 is arranged to shield the sensor electrode 3 and the reference sensor electrode 15 from interference occurring in the area of ​​the vehicle structure 11, which is designed as the frame of the vehicle door 12. Alternatively, the shielding electrode 13 can also be designed as a shielding cable with an electrical conductor, for example a copper conductor, and an electrical insulation surrounding it, for example a plastic or rubber insulation.

[0053] When using the shielding electrode 13, the sensor electrode 3 and the reference sensor electrode 15 are, for example, not coupled to the electrical ground potential GND via the capacitors 9, 19. The shielding electrode 13 is specifically coupled to the ground potential GND and is arranged, in particular, between the sensor electrode 3 and the edge of the opening O.

[0054] In the illustrated embodiment of device 1, the detection of an imminent entrapment event is carried out analogously to the detection described above. Fig. 1, wherein the shielding electrode 13 provides a directed, in particular downward-directed, measuring range and shielding against disturbances occurring on a side facing away from the measuring range. Thus, the device 1 is rendered insensitive to disturbances.

[0055] Fig. Figure 5 shows a flowchart of a possible embodiment of a method for detecting a jamming event of a motor-operated locking system of a vehicle 2.

[0056] In the first process step S1, the charging phase is executed by applying a positive electrical potential to the reference sensor electrode 15 via control pin 18, causing negative charges to migrate onto the reference sensor electrode 15. Simultaneously, the electrical potential of the reference sensor electrode 15 and the resulting distribution of negative charges on the reference sensor electrode 15 are measured at measuring pin 16.

[0057] At the first branch V1, it is checked whether the electrical potential measured at measuring pin 16 has reached the specified threshold. If this is not the case, indicated by a "no" branch N1, the charging phase continues.

[0058] Once the electrical potential measured at pin 16 reaches the predefined threshold, represented by a yes branch J1, the control unit 5, in a second process step S2, applies the electrical ground potential GND to control pin 18, thus initiating the discharge phase and allowing negative and positive charges to flow back from the reference sensor electrode 15. The control unit 5 records the time from when the threshold is reached until the minimum threshold value of the electrical potential, caused by the charge flow back, is reached. A timer reset occurs before the discharge phase begins.

[0059] The discharge phase continues until the minimum threshold is reached. In a second branch V2, the control unit 5 checks whether the minimum threshold has been reached. If this is not the case, represented by a "no" branch N2, the timer is incremented in a third process step S3.

[0060] If, on the other hand, the minimum threshold value is reached, represented by a yes branch J2, a timer value, i.e. the measured time duration, is equated to a residual charge quantity in a fourth process step S4.

[0061] Subsequently, in a fifth process step S5, an asymmetric filtering of the timer value is carried out using an asymmetric low-pass filter, whereby a reduction in the discharge time is weighted more heavily and thus a relationship to a distance of a detectable object can be established.

[0062] Subsequently, the process steps S1 to S5 are carried out analogously for the sensor electrode 3 and a correspondingly filtered timer value T2, i.e. a duration of the discharge, is generated.

[0063] Once the filtered timer value T1 for the reference sensor electrode 15 and the timer value T2 for the sensor electrode 3 are available, a difference value is calculated in a sixth process step S6 to determine the difference between the two timer values ​​T1 and T2, i.e., between the time recorded for sensor electrode 3 and the time recorded for reference sensor electrode 15 until the minimum threshold of the electrical potential is reached. This is done by subtracting the timer value T1 for reference sensor electrode 15 from the timer value T2 for sensor electrode 3.

[0064] In branch V3, it is checked whether the difference value is consistently negative, meaning that the timer value T1 of the reference sensor electrode 15 is consistently greater than the timer value T2 for the sensor electrode 3. If this is the case, represented by a "yes" branch J3, an offset calculation is performed in a seventh process step S7, and the reference sensor electrode 15 is calibrated using this calculation.

[0065] If the difference value is positive or consistently negative, i.e., the timer value T1 of the reference sensor electrode 15 is smaller than the timer value T2 for the sensor electrode 3, represented by a no branch N3, the difference value is filtered in an eighth process step S8 using a low-pass filter.

[0066] Subsequently, in a further branch V4, it is checked whether the difference value exceeds the predefined threshold. If this is the case, represented by a "yes" branch J4, an object is detected in a ninth process step S9, and a conclusion is drawn that an imminent entrapment event is occurring. If this is not the case, represented by a "no" branch N4, the process is restarted according to process step S10.

[0067] Because the filtering of the timer values ​​T1 and T2 for the discharge times is identical for both electrodes, identical values ​​result under constant environmental conditions. Therefore, if the discharge times of the reference sensor electrode 15 and the sensor electrode 3 are the same, it can be concluded that no object is present in the entrapment area.

[0068] In Fig. Figure 6 shows a flowchart of a possible embodiment of a method for preventing a jamming event of a motor-operated locking system of a vehicle 2, in particular a window pane.

[0069] This procedure follows directly from the ninth procedure step S9 of the in Fig. The procedure described in section 5 is followed, whereby a branch V5 checks whether a window closing signal F is present. If this is not the case, represented by a "no" branch N5, the procedure continues according to... Fig. 5 restarted.

[0070] However, if a window closing signal F is present and an object was previously detected, represented by a yes branch J5, a further branch V6 checks whether a window pane position POS of an upper pane edge is in a Fig. The critical area K, as shown in more detail in section 7, is located. If this is not the case, represented by a "no" branch N6, the system jumps back to the previous branch V5 and checks for the presence of the window closing signal F.

[0071] If, on the other hand, the window pane position POS is in the critical area K, represented by a Yes branch J6, in an eleventh process step S11 a movement of the window pane is stopped or reversed in order to avoid a jamming event.

[0072] Fig. Figure 7 shows a vehicle door 12 with an opening O designed as a window opening and a closing element 4 designed as a window pane, wherein the vehicle door 12 is designed according to the Fig.The vehicle door 12 shown in Figure 4 is designed as follows. A critical area K is shown below an upper edge of the opening O, wherein a lower edge of the critical area K represents in particular the area in which a pinching event between an upper edge of the window pane and the upper edge of the opening O is probable.

Claims

[1] Device (1) for detecting a pinching event of a motor-operated locking system of a vehicle (2) - with a sensor electrode (3) which surrounds at least in sections an opening (O) of the vehicle (2) which can be closed by means of at least one closure element (4), wherein - the sensor electrode (3) is arranged in a sealing element (10) which at least partially surrounds the opening (O), characterized by , that - a reference sensor electrode (15) is provided which surrounds the opening (O) of the vehicle (2) at least in sections, - the reference sensor electrode (15) is arranged at a distance from the sensor electrode (3) in the sealing element (10) and has a greater distance from the opening (O) than the sensor electrode (3), - a control unit (5) is provided which is designed - applying an electrical potential for a charging process and a ground potential (GND) for a discharging process to the sensor electrode (3) and the reference sensor electrode (15), - to record a time period until a minimum threshold value of the electrical potential for the sensor electrode (3) and the reference sensor electrode (15) is reached, caused by a return flow of charges via the ground potential (GND), - to determine a difference between the time duration recorded for the sensor electrode (3) and the time duration recorded for the reference sensor electrode (15) and - to conclude that an imminent trapping event is imminent if the difference exceeds a predetermined threshold value and if the time duration recorded for the sensor electrode (3) deviates from a predetermined standard time duration or from a standard time duration recorded in a state without an imminent trapping event. [2] Device (1) according to claim 1, characterized by that the control unit (5) is further designed to carry out the charging process and the discharging process for the sensor electrode (3) and the reference sensor electrode (15) in a periodically offset manner such that the charging process and the discharging process of the sensor electrode (3) start after the charging process and the discharging process of the reference sensor electrode (15) have been completed, or vice versa. [3] Device (1) according to claim 1 or 2, characterized by , that - the sensor electrode (3) is arranged in an inner sealing lip of the sealing element (10) and - the reference sensor electrode (15) is arranged in an outer sealing lip of the sealing element (10). [4] Device (1) according to one of the preceding claims, characterized by , that - the control unit (5) and the sensor electrode (3) are coupled to a first measuring pin (6), - the control unit (5) and the reference sensor electrode (15) are coupled to a second measuring pin (16), - the control unit (5) is coupled to a first control pin (8) and the sensor electrode (3) is coupled to the first control pin (8) via a high-ohm electrical resistor (7), - the control unit (5) is coupled to a second control pin (18) and the reference sensor electrode (15) is coupled to the second control pin (18) via a high-ohm electrical resistor (17), - the control unit (5) is designed - to apply the respective electrical potential to the sensor electrode (3) and the reference sensor electrode (15) via the first control pin (8) and the second control pin (18), - to simultaneously measure the electrical potential of the sensor electrode (3) and a distribution of negative charges on the sensor electrode (3) at the first measuring pin (6), - to simultaneously measure the electrical potential of the reference sensor electrode (15) and a distribution of negative charges on the reference sensor electrode (15) at the second measuring pin (16), - as soon as the electrical potentials measured at the measuring pins (6, 16) reach a predetermined threshold value, the electrical ground potential (GND) is applied to the control pins (8, 18) so that the charges flow back from the sensor electrode (3) and the reference sensor electrode (15), and - to record the respective time period from the reaching of the threshold value until the reaching of a minimum threshold value of the electrical potential for the sensor electrode (3) and the reference sensor electrode (15) caused by the return flow of the charges. [5] Device (1) according to one of the preceding claims, characterized bythat the sensor electrode (3) and the reference sensor electrode (15) are each coupled to the ground potential (GND) via an electrical capacitor (9, 19). [6] Device (1) according to one of the preceding claims, characterized by that the sensor electrode (3) and the reference sensor electrode (15) are each designed as a sensor cable with an electrical conductor (3.1, 15.1) and an electrical insulation (3.2, 15.2) surrounding it. [7] Device (1) according to one of the preceding claims, characterized by that a shielding electrode (13) for shielding the sensor electrode (3) and the reference sensor electrode (15) against occurring interference is arranged in a vehicle frame element or vehicle roof pillar surrounding the opening (O) at least in sections. [8] Device (1) according to claim 1, characterized bythat the control unit (5) is further designed to conclude that an imminent pinching event is imminent if, in addition, when the closing movement of the closure element (4) is activated, it turns out that the closure element (4) is located in a predetermined critical area (K). [9] Method for operating a device (1) according to one of the preceding claims, wherein - the electrical potential for the charging process and the ground potential (GND) for the discharging process are applied to the sensor electrode (3) and the reference sensor electrode (15), respectively, - a time period is recorded until a minimum threshold value of the electrical potential for the sensor electrode (3) and the reference sensor electrode (15) is reached, caused by the return flow of the charges via the ground potential (GND), - a difference between the time duration recorded for the sensor electrode (3) and the time duration recorded for the reference sensor electrode (15) is determined and - if the difference exceeds a predetermined threshold value and if the time duration recorded for the sensor electrode (3) deviates from a predetermined standard time duration or from a standard time duration recorded in a state without an imminent pinching event, it is concluded that an imminent pinching event is occurring. [10] Device for preventing a pinching event of a motor-operated locking system of a vehicle (2), comprising - a device (1) for detecting a pinching event according to one of claims 1 to 8 and - at least one control unit for controlling a motor drive of the closure element (4), wherein the control unit is designed to stop and / or reverse a closing movement of the closure element (4) in the event of an imminent pinching event.

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