Detecting and avoiding pinch events

Abstract

The invention relates to a device (1) for detecting a pinch event in a motor-operated closing system of a vehicle (2), comprising a sensor electrode (3) at least partially surrounding at its edge an opening (O) of the vehicle (2) that is closable by at least one closing element (4) and a reference sensor electrode (15). A control device (5) is provided, which control device (5) comprises: -In the charging process, a potential is applied to the sensor electrode (3) and the reference sensor electrode (15), and in the discharging process, a ground potential (GND) is applied to the sensor electrode (3) and the reference sensor electrode (15), respectively. - detecting the time required for the potential of the sensor electrode (3) and the reference sensor electrode (15) to reach a minimum threshold value caused by a backflow of charge due to the ground potential (GND); - calculating the difference between the time required for the sensor electrode (3) and the time required for the reference sensor electrode (15); configured to conclude that a pinch event is imminent if this difference exceeds a defined threshold such that the duration detected for the sensor electrode (3) deviates from a defined standard duration or from a standard duration detected in a state in which a pinch event is detected as not imminent.

Description

[Technical field]

[0001] The invention relates to a device for detecting a pinch event in a motor-operated closing system of a vehicle according to the preamble of claim 1. [Background technology]

[0002] Furthermore, the present invention also relates to a method of operating such an apparatus and to an apparatus for avoiding a pinch event in a motor-operated closing system of a vehicle.

[0003] From the patent application DE 10 200 03 133 A1 a device for avoiding pinching events in a motor-operated closing system of a vehicle is known. The device comprises a sensor electrode which at least partially surrounds at its edge an opening in the vehicle which can be closed by a closing element. Furthermore, the device comprises a microcontroller, a measurement pin connected to the microcontroller and to the sensor electrode, and a control pin connected to the microcontroller and to the sensor electrode via a high impedance electrical resistor. The microcontroller is configured to apply a potential to the sensor electrode via the control pin and to simultaneously measure the potential of the sensor electrode and the distribution of negative charges on the sensor electrode with the measurement pin. When the potential measured at the measurement pin reaches a defined threshold, the microcontroller applies a ground potential to the control pin, so that charges flow back from the sensor electrode. Furthermore, the microcontroller is configured to detect the time required from the reaching of the threshold potential to the reaching of a minimum threshold caused by the backflow of charges and to conclude that a pinching event is imminent if the detected time deviates from a defined standard time required or from a standard time required that is detected in a state in which a pinching event is not detected as imminent. [Patent Document 1] DE 10 2020 002 817 A1

[0004] Furthermore, from the patent document 2, a device for controlling and monitoring a motorized window pane of a motor vehicle, movable between an open position and a closed position, is known. The device includes a sensor with a sensor electrode, which generates an electric field in the opening area of ​​a closure element. Furthermore, in the device, a control device is connected to the sensor, which detects a change in the capacitance of the sensor electrode and provides a control signal, the control device detecting a change in the capacitance of the sensor electrode based on the presence of a wet film on the closure element. [Patent Document 2] DE 10 2004 002 415 A1

[0005] Patent document 3 describes an anti-pinch device for detecting the presence of an object in a sensing area. The anti-pinch device comprises a housing part, a ground electrode embedded in the housing part, and a sensor electrode disposed at a distance from the ground electrode and embedded in the housing part. The sensor electrode and the ground electrode are charged to different potentials. The housing part is manufactured from a non-conductive material and insulates the sensor electrode with respect to the ground electrode. Furthermore, the anti-pinch device comprises a zone of reduced stiffness between the ground electrode and the sensor electrode, the zone of reduced stiffness being disposed in the housing part and co-extruded together with the housing part. The zone of reduced stiffness is also provided in the form of a void in the housing part or in the form of a material with a higher elasticity than the material of the housing part, the material with a higher elasticity being manufactured from foam rubber. The housing part comprises a conductive region surrounding the sensor electrode and a conductive region surrounding the ground electrode. Furthermore, the anti-pinch device comprises a device for creating an input signal applied to the sensor electrode and for receiving an output signal from the sensor electrode. The device can receive two output signals, the output signal changing in response to a change in capacitance between the sensor electrode and the ground electrode when a dielectric is present in the sensing region, and the output signal changing in response to a change in capacitance between the sensor electrode and the ground electrode when a non-conductive object is present based on a change in the mutual position of the sensor electrode and the ground electrode. [Patent Document 3] EP 1 154 110 A2 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention is based on the problem of providing, compared to the prior art, an improved device for detecting a pinch event in a motor-operated closing system of a vehicle, an improved method of operating such a device, and an improved device for avoiding a pinch event in a motor-operated closing system of a vehicle. [Means for solving the problem]

[0007] This problem is solved according to the invention by - a device having the features of claim 1 for detecting a pinching event in a motor-operated closing system of a vehicle, - a method having the characteristics as recited in claim 9, - a device for avoiding pinch events in a motor-operated closing system of a vehicle, the device having the features according to claim 10; is solved by:

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

[0009] The device for detecting a pinch event in a motor-operated closing system of a vehicle comprises a sensor electrode at least partially surrounding an opening in the vehicle closeable by at least one closing element at its edge, the sensor electrode being arranged on a sealing element at least partially surrounding the opening.

[0010] According to the invention, a reference sensor electrode is provided which at least partially surrounds the vehicle opening at its edge, the reference sensor electrode being arranged on the sealing element at a distance from the sensor electrode and at a greater distance from the opening than the sensor electrode, and a control device is provided which is configured to apply a potential to the sensor electrode and the reference sensor electrode in a charging process and a ground potential in a discharging process, respectively, and to detect the time required for the potentials of the sensor electrode and the reference sensor electrode to reach a minimum threshold value caused by a backflow of charge by the ground potential, respectively, and is further configured to calculate the difference between the time required for the sensor electrode and the time required for the reference sensor electrode and to conclude that a pinch event is imminent if this difference exceeds a defined threshold value and if the time required for the sensor electrode deviates from a defined standard time required or from a standard time required for detection in a state in which a pinch event is not detected as imminent.

[0011] The device is adapted for use in a vehicle to detect a pinch event, for example between a closure element and a vehicle structure at least partially surrounding an edge of the closure element, for example a motor-operated window pane and a vehicle structure at least partially surrounding an edge of the window opening, or a motor-operated vehicle door and a vehicle structure at least partially surrounding an edge of the vehicle door.

[0012] The safety requirements for so-called window regulator entrapment protection in vehicles demand a high level of reactivity that cannot be ensured, for example, with known current-based entrapment protection. This is due, in particular, to the relatively high stiffness of the test object for testing the entrapment protection of 65 N / mm. In this case, the test object represents, for example, the characteristics of a child's finger. Furthermore, the reaction performance of known entrapment protection systems is strongly limited by the time constant of the system, which indicates the time required for the window glass to react from the control of the window regulator motor. With frameless vehicle doors, in particular, the difficulty is that the freely positionable test object angle and test angle position make it impossible to ensure guidance of the window glass in the upper block. This also applies to door entrapment protection systems.

[0013] In contrast, the device according to the invention allows for a preventive jam protection, which allows a reaction without the occurrence of a jam force. This means that before a jam force occurs, objects and body parts can be detected in the window guide or door opening and in dangerous jam areas, for example near the seal. This allows compliance with the future safety requirements FMVSS-118. In this case, the device can be realized with particularly low material and expenditure. Here, the detection takes place contactlessly as well as contactlessly and is made particularly robust. The detection range is, for example, 0.5 cm to 5 cm. In particular, a high robustness is achieved compared to capacitive systems due to the continuous recalibration of the discharge time, i.e. the time required for the potential to reach the minimum threshold value caused by the backflow of the charge. Here, a very high robustness against humidity and system changes is obtained. This robustness is also achieved by the fact that the synchronization of the position of the window glass with the activation of the jam protection, which is made possible by this position, is only possible in the dangerous area. It is also not necessary for the jam object to be connected to ground potential.

[0014] In the case of devices using only active sensor electrodes, the environmental characteristics forming the so-called baseline are determined by the same sensor electrodes as slow low-pass values, from which fast low-pass values ​​are also formed, and thus a difference value is calculated. It is therefore not possible to distinguish whether changes occur locally in the pinch area or over a wider area, for example due to external electric and magnetic fields. To avoid false detections, therefore, a high threshold must be set, which must be exceeded in the measurements performed by the sensor electrodes, resulting in a low sensitivity. This possible sensitivity is additionally reduced by the interaction of the sensor electrodes with the charge distribution of the vehicle body, since stronger electric field interactions than those caused by the pinched object can occur. A pinched object remaining in the pinch area cannot be detected, since the baseline is continuously adapted to the actual conditions currently present. In contrast, the present device uses a reference sensor electrode to calculate the environmental characteristics and from which a robust baseline is calculated, thereby allowing the use of lower threshold values ​​at the same time as a high robustness against false detections. Thus, being able to react to smaller differential values ​​advantageously increases the sensitivity of the device, reduces sluggishness in detecting a pinch event, and reduces the number of false positives. It also makes it possible to distinguish between local interactions of the pinch area acting preferentially on one electrode and interactions due to external influences acting on both electrodes (e.g. interactions between the sensor electrodes and the charge distribution on the vehicle body, external electric and magnetic fields, etc.), i.e. it is possible to distinguish between local and wide-area events.

[0015] In a possible embodiment of the device, the control device is further configured to periodically stagger the charging and discharging processes of the sensor electrode and the reference sensor electrode, so that the start of the charging and discharging processes of the sensor electrode occurs after the end of the charging and discharging processes of the reference sensor electrode, or vice versa, so that one of both electrodes is always inactive, effectively and easily avoiding mutual interference of the electrodes when detecting measured values.

[0016] In a further possible embodiment of the device, the sensor electrode is arranged on the inner sealing lip of the sealing element and the reference sensor electrode is arranged on the outer sealing lip of the sealing element, which allows a simple and protected integration of both electrodes, with the reference sensor electrode being arranged close to the sensor electrode but not directly facing the clamping area and / or not being arranged in the clamping area.

[0017] In a further possible embodiment of the device, the control device and the sensor electrode are connected to a first measurement pin, and the control device and the reference sensor electrode are connected to a second measurement pin. Furthermore, the control device is connected to a first control pin, the sensor electrode is connected to the first control pin via a high impedance electrical resistor, the control device is connected to a second control pin, and the reference sensor electrode is connected to the second control pin via a high impedance electrical resistor. The control device is configured to apply respective potentials to the sensor electrode and the reference sensor electrode via the first control pin and the second control pin, to simultaneously measure the potential of the sensor electrode and the distribution of negative charges on the sensor electrode at the first measurement pin, and to simultaneously measure the potential of the reference sensor electrode and the distribution of negative charges on the reference sensor electrode at the second measurement pin. Furthermore, the control device is configured to apply a ground potential to the control pin as soon as the potential measured at the control pin reaches a respective defined threshold, thereby causing charges to flow back from the sensor electrode and the reference sensor electrode, and to detect the time taken for the potentials of the sensor electrode and the reference sensor electrode to reach a threshold and a minimum threshold caused by the backflow of charges, respectively. This embodiment is characterized by an easily realizable structure, reliable operation, and high robustness against disturbances, and can be realized with low material costs and expenses.

[0018] In a further possible embodiment of the device, the sensor electrode and the reference sensor electrode are each connected to ground potential via an electric capacitor.

[0019] In a further possible embodiment of the device, the sensor electrode and the reference sensor electrode are configured as a sensor cable with an electrical conductor and a surrounding electrical insulator. This allows a particularly simple, long-lasting and cost-effective configuration of the sensor electrode and the reference sensor electrode. It is therefore also easily possible to integrate both electrodes into the sealing element.

[0020] In a further possible embodiment of the device, a shield electrode for shielding the sensor electrode and the reference sensor electrode against occurring interferences is arranged on a vehicle frame element or on a vehicle roof bar that at least partially surrounds the opening. The shield electrode then allows shielding against interferences occurring on the opposite side of the measuring area, so that insensitivity of the device to interferences can be achieved. Arranging the shield electrode in the vehicle frame element or in the vehicle roof bar ensures a reliable function of the shield electrode on the one hand and allows easy installation in the vehicle interior on the other hand.

[0021] In a further possible embodiment of the device, the control device is further configured to conclude that a pinching event is imminent if, during the closing operation of the closing element, the closing element is additionally found to be in a defined danger area, thus making it possible to avoid false triggering of the pinching protection, in particular if, during the closing operation of the closing element, a pinching object moves out of the area between the closing element and the surrounding vehicle structure.

[0022] In a method according to the invention for operating the previously mentioned device, a potential is applied to the sensor electrode and a ground potential is applied to the reference sensor electrode in a charging process and a ground potential is applied to the reference sensor electrode in a discharging process, respectively, and the time required for the potential of the sensor electrode and the reference sensor electrode to reach a minimum threshold caused by the backflow of charge by the ground potential is detected, and the difference between the time required for the sensor electrode and the time required for the reference sensor electrode is calculated and it is concluded that a pinch event is imminent if this difference exceeds a defined threshold and if the time required for the sensor electrode deviates from a defined standard time or from a standard time detected in a state where a pinch event is detected as not imminent.

[0023] The method uses a reference sensor electrode to calculate the environmental characteristics and a robust baseline therefrom, allowing the use of lower thresholds while at the same time increasing robustness against false positives. The method is therefore advantageously more sensitive, less sluggish in detecting pinch events and less likely to produce false positives, due to the ability to react to smaller differential values. It is also possible to distinguish between local interactions of the pinch area acting preferentially on one electrode and interactions due to external influences acting on both electrodes (e.g. interaction of the sensor electrode with the charge distribution of the vehicle body, external electric and magnetic fields, etc.). In other words, it is possible to distinguish between local and global events.

[0024] The device according to the invention for avoiding a pinch event in a motor-operated closing system of a vehicle comprises the already mentioned device for detecting a pinch event and at least one control device for controlling the motor drive of the closing element, which control device is configured to stop and / or reverse the closing movement of the closing element if a pinch event is imminent. The device allows a particularly reliable avoidance of a pinch event while minimizing false detections and false activations.

[0025] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic electrical circuit diagram of an apparatus for detecting a pinch event in a motor-operated closing system of a vehicle. [Diagram 2] FIG. [Diagram 3] 3 shows a schematic perspective cross-section of a part of the vehicle according to FIG. 2 in the region of the vehicle structure and sealing elements; [Figure 4] 1 shows a schematic perspective cross-section of a portion of a vehicle door in the region of a sealing element; [Diagram 5] 4 is a flow chart of a possible embodiment of a method for detecting a pinch event in a motorized closing system of a vehicle. [Figure 6] 4 is a flow chart of a possible embodiment of a method for avoiding a pinch event in a motorized closing system of a vehicle. [Figure 7] FIG. 1 is a schematic diagram of a vehicle door having a window opening and a window glass. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Corresponding parts are labeled with the same reference numerals in all figures.

[0028] FIG. 1 shows an electrical circuit diagram of a possible embodiment of a device 1 for detecting a pinch event in a motor-operated closing system of a vehicle 2, which is shown in detail in FIG.

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

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

[0031] Here, the sensor electrode 3 and the reference sensor electrode 15 together at least partially surround the opening O and are arranged in a sealing element 10 which is illustrated in detail in FIGS.

[0032] Furthermore, the device 1 comprises a control device 5, such as a microcontroller, a measurement pin 6 connected to the control device 5 and to the sensor electrode 3, and a control pin 8 connected to the control device 5 and to the sensor electrode 3 via a high impedance electrical resistor 7.

[0033] Furthermore, the device 1 comprises a measurement pin 16 connected to the control device 5 and to the reference sensor electrode 15, and a control pin 18 connected to the control device 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 are connected to the ground potential GND of the vehicle 2 via electric capacitors 9, 19, respectively. In an embodiment not shown in detail, the capacitors 9, 19 may be omitted.

[0035] The sensor electrode 3 and the reference sensor electrode 15 are configured as sensor cables with electrical conductors 3.1, 15.1 and surrounding electrical insulators 3.2, 15.2, respectively. The electrical conductors 3.1, 15.1 are configured as copper conductors, for example, and the electrical insulators 3.2, 15.2 are configured as plastic or rubber insulators, for example. 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 configured identically in order to improve the comparability of the measurement results detected by them.

[0036] The control device 5 is configured to apply a potential to the sensor electrode 3 via the control pin 8, and at the same time measure the potential of the sensor electrode 3 and the resulting distribution of negative charges on the sensor electrode 3 with the measurement pin 6. At this time, when the potential measured with the measurement pin 6 reaches a defined threshold, the control device 5 applies a ground potential GND to the control pin 8, which causes the negative and positive charges to flow back from the sensor electrode 3. In this case, the control device 5 detects the time required from when the potential reaches the threshold to when it reaches the minimum threshold caused by the backflow of charges.

[0037] Furthermore, the control device 5 is configured to apply a potential to the reference sensor electrode 15 via the control pin 18, similar to the procedure for the sensor electrode 3, and at the same time measure the potential of the reference sensor electrode 15 and the resulting distribution of negative charges on the reference sensor electrode 15 with the measurement pin 16. In this case, when the potential measured with the measurement pin 16 reaches a specified threshold, the control device 5 applies a ground potential GND to the control pin 18, which causes the negative and positive charges to flow back from the reference sensor electrode 15. In this case too, the control device 5 detects the time required from when the potential reaches the threshold to when it reaches the minimum threshold caused by the backflow of charges.

[0038] By means of the reference sensor electrode 15, environmental characteristics are then calculated which form the so-called baseline. This baseline represents the external global basic conditions, i.e. influences acting on both the sensor electrode 3 and the reference sensor electrode 15. These influences are, for example, the interaction of the sensor electrode 3 and the reference sensor electrode 15 with the charge distribution of the vehicle body, external charge distributions, external electric and magnetic fields, etc. It is then assumed in particular that the external global changes take place significantly slower than the cycle time used, for example .about.50 μs.

[0039] The charging and discharging processes of the sensor electrode 3 and the reference sensor electrode 15 are cyclically staggered such that the start of the charging and discharging process of the sensor electrode 3 occurs after the end of the charging and discharging process of the reference sensor electrode 15 and vice versa, i.e. one of both electrodes is always inactive, thus avoiding mutual interference of the electrodes.

[0040] Furthermore, the difference between the duration detected for the sensor electrode 3 and the duration detected for the reference sensor electrode 15 is calculated. If the difference exceeds a defined threshold such that the duration detected for the sensor electrode 3 deviates from a defined standard duration or from a standard duration detected in a state where a pinch event is detected as not imminent, the controller 5 concludes that a pinch event is imminent.

[0041] This deviation from the standard time required is due to the external influence of the object (e.g. a human limb) fixing a negative charge in the sensor electrode 3, thereby preventing backflow and resulting in non-uniformity in the charge distribution in the sensor electrode 3.

[0042] By comparing the measurements detected by the sensor electrodes 3 with a baseline, differences of local origin, e.g. the approach of a body part, can be reliably detected. This allows for high robustness and makes local slow effects (>50 ms) more stable to be detected. Calibration of the sensor electrodes 3 to the environment by slow low-pass filters is not required.

[0043] 2 shows a partial side view of a vehicle 2, which is equipped with a frameless vehicle door (not shown). In a vehicle door of this kind, a closure element 4 configured as a window pane is sealed by at least one sealing element 10 which at least partially surrounds an opening O (here a window opening) at its edge in the closed state of the vehicle door and in the closed state of the window pane. In the illustrated embodiment, the sealing element 10 is arranged in the vehicle structure 11 which is formed by a roof bar.

[0044] Figure 3 shows a schematic perspective view of a section of a part of the vehicle 2 according to Figure 2 in the region of the vehicle structure 11 and the sealing element 10. Here, the sealing element 10 is configured as a so-called bubble-shaped roof seal.

[0045] In order to detect an impending pinch event and thereby avoid a pinch event between the window pane and the sealing element 10 according to the description of figure 1, the sensor electrode 3 is arranged in the sealing element 10 completely and directly surrounded by the sealing material 10.1 or alternatively in the cavity 10.2, whereby the sensor electrode 3 is arranged in particular on the inner sealing lip of the sealing element 10.

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

[0047] Furthermore, a shield electrode 13 for shielding the sensor electrode 3 and the reference sensor electrode 15 against occurring interferences is arranged in the region of the vehicle structure 11 configured as a roof bar. Alternatively, the shield electrode 13 may be configured as a shielded cable with an electrical conductor (e.g. a copper conductor) and an electrical insulator (e.g. a plastic or rubber insulator) surrounding it.

[0048] When using a shield electrode 13, the sensor electrode 3 and the reference sensor electrode 15 are connected to the ground potential GND, for example without via the capacitors 9, 19. The shield electrode 13 is in particular connected to the ground potential GND and is in particular arranged between the sensor electrode 3 and the edge of the opening O.

[0049] The detection of an impending pinching event is carried out in the illustrated embodiment of the device 1 in a similar manner to the described detection according to Fig. 1, with the shield electrode 13 providing shielding against disturbances occurring on the opposite side of the oriented, in particular downwardly oriented, measurement area, so that insensitivity of the device 1 to disturbances is achieved.

[0050] 4 shows a perspective view of a section of a part of a vehicle door 12 in the region of the sealing element 10, the vehicle door 12 being configured as a so-called frame door, the frame of which forms the vehicle structure 11 in which the sealing element 10 for sealing against the window pane in the closed state is arranged. The sealing element 10 is hereby configured as a frame seal of the frame of the vehicle door 12.

[0051] In order to detect a pinch event between the window pane and the sealing element 10 by sensing an impending pinch event according to the description of figure 1, the sensor electrode 3 and the reference sensor electrode 15 are arranged in the sealing element 10 either completely and directly surrounded by the sealing material 10.1 or in the cavity 10.2. In this case, the reference sensor electrode 15 is arranged at a greater distance to the opening O than the sensor electrode 3.

[0052] Furthermore, a shield electrode 13 for shielding the sensor electrode 3 and the reference sensor electrode 15 against occurring interferences is arranged in the region of the vehicle structure 11 configured as a frame of the vehicle door 12. Alternatively, the shield electrode 13 may be configured as a shielded cable having an electrical conductor (e.g. a copper conductor) and an electrical insulator (e.g. a plastic or rubber insulator) surrounding it.

[0053] When using a shield electrode 13, the sensor electrode 3 and the reference sensor electrode 15 are connected to the ground potential GND, for example without via the capacitors 9, 19. The shield electrode 13 is in particular connected to the ground potential GND and is in particular arranged between the sensor electrode 3 and the edge of the opening O.

[0054] The detection of an impending pinching event is carried out in the illustrated embodiment of the device 1 in a similar manner to the described detection according to Fig. 1, with the shield electrode 13 providing shielding against disturbances occurring on the opposite side of the oriented, in particular downwardly oriented, measurement area, so that insensitivity of the device 1 to disturbances is achieved.

[0055] FIG. 5 shows a flow chart of a possible embodiment of a method for detecting a pinch event in a motorized closing system of a vehicle 2 .

[0056] Initially, in a first step S1, a charging step is performed in which a positive potential is applied to the reference sensor electrode 15 via the control pin 18, whereby a negative charge is transferred to the reference sensor electrode 15. At the same time, at the measurement pin 16, the potential of the reference sensor electrode 15 and the resulting distribution of negative charges on the reference sensor electrode 15 are measured.

[0057] In a first branch V1 it is checked whether the potential measured at the measuring pin 16 reaches a defined threshold value. If this is not the case (indicated by the "No" branch N1), the charging phase continues to be carried out.

[0058] If the potential measured at the measuring pin 16 reaches a defined threshold (indicated by the "Yes" branch J1), the control device 5 applies the ground potential GND to the control pin 18 in a second step S2, which starts the discharge phase and causes negative and positive charges to flow back from the reference sensor electrode 15. In this case, the control device 5 detects the time taken from when the potential reaches the threshold to when it reaches the minimum threshold caused by the backflow of charges. Before the start of the discharge phase, a timer reset is performed.

[0059] The discharge phase is then carried out until a minimum threshold is reached. In a second branch V2, the control device 5 checks whether the minimum threshold has been reached. If this is not the case (indicated by the "No" branch N2), a timer is incremented in a third step S3.

[0060] On the other hand, if the minimum threshold has been reached (indicated by "Yes" branch J2), then in a fourth step S4 the timer value, ie the measured elapsed time, is made equal to the residual charge.

[0061] Subsequently, in a fifth step S5, an asymmetric filtering of the timer value is performed by an asymmetric low-pass filter, in order to weight the shortening of the discharge time more strongly, so that a relationship with the distance of the detectable object can be established.

[0062] Steps S1 to S5 are then similarly performed for the sensor electrode 3 to form a suitably filtered timer value T2, ie the duration of the discharge.

[0063] As soon as the filtered timer value T1 for the reference sensor electrode 15 and the timer value T2 for the sensor electrode 3 are available, in a sixth step S6, a difference value is formed between both timer values ​​T1, T2, i.e. between the time determined for the sensor electrode 3 until the potential reaches the minimum threshold value and the time determined for the reference sensor electrode 15. The timer value T1 for the reference sensor electrode 15 is then subtracted from the timer value T2 for the sensor electrode 3.

[0064] In branch V3 it is checked whether the difference value is always negative, i.e. whether the timer value T1 of the reference sensor electrode 15 is always greater than the timer value T2 of the sensor electrode 3. If this is the case (indicated by branch J3 "yes"), in a seventh step S7 an offset calculation is performed with which the reference sensor electrode 15 is calibrated.

[0065] If the difference value is positive or always negative, i.e. if the timer value T1 of the reference sensor electrode 15 is smaller than the timer value T2 of the sensor electrode 3 (indicated by the "No" branch N3), then in an eighth step S8 the difference value is filtered using a low-pass filter.

[0066] Subsequently, in a further branch V4, it is checked whether the difference value exceeds a defined threshold value. If this is the case (indicated by the "yes" branch J4), it is concluded in a ninth step S9 that an object has been detected and that a pinching event is imminent. If this is not the case (indicated by the "no" branch N4), the method is resumed according to step S10.

[0067] The same filtering of the timer values ​​T1, T2 for the discharge times of both electrodes results in identical values ​​for certain environmental characteristics, from which it can be concluded that if the discharge times of the reference sensor electrode 15 and the sensor electrode 3 are the same, no object is present in the pinch area.

[0068] In FIG. 6 a flow chart of a possible embodiment of a method for avoiding a pinch event in a vehicle 2, in particular in a motorized window closing system, is shown.

[0069] The method follows immediately after the ninth step S9 of the method shown in figure 5, where in branch V5 it is checked whether there is a window close signal F. If this is not the case (indicated by the "no" branch N5), the method is started anew according to figure 5.

[0070] However, if a window close signal F is present and an object has been previously detected (indicated by "yes" branch J5), then in a further branch V6 it is checked whether the window glass position POS of the upper glass edge is within the danger area K, which is shown in detail in Fig. 7. If this is not the case (indicated by "no" branch N6), then it returns to the previous branch V5 and to the check whether a window close signal F is present.

[0071] On the other hand, if the window glass position POS is within the danger zone K (indicated by the "Yes" branch J6), then in an eleventh step S11 the movement of the window glass is stopped or reversed and a pinch event is avoided.

[0072] Figure 7 shows a vehicle door 12 with an opening O configured as a window opening and a closure element 4 configured as a window glass, which is configured according to the vehicle door 12 shown in Figure 4. At the lower part of the upper edge of the opening O a danger area K is shown, the lower edge of which shows in particular an area prone to pinching events between the upper edge of the window glass and the upper edge of the opening O.

Claims

1. A device (1) for detecting a pinch event in a motor operated closing system of a vehicle (2), comprising: - comprising a sensor electrode (3) at least partially surrounding, at its edge, an opening (O) in said vehicle (2) that is closable by at least one closure element (4), - said sensor electrode (3) is arranged on a sealing element (10) which at least partially surrounds said opening (O); In the device (1), a reference sensor electrode (15) is provided which at least partially surrounds said opening (O) of said vehicle (2) at its edge, the reference sensor electrode (15) is arranged on the sealing element (10) at a distance relative to the sensor electrode (3) and has a greater distance relative to the opening (O) than the sensor electrode (3); a control device (5) is provided, said control device (5) comprising: - applying a potential to the sensor electrode (3) and a ground potential (GND) to the reference sensor electrode (15) during the charging process and during the discharging process, respectively; - detecting the time required for the potential of the sensor electrode (3) and the reference sensor electrode (15) to reach a minimum threshold caused by the backflow of charges due to the ground potential (GND), - calculating the difference between the time taken for the sensor electrode (3) and the time taken for the reference sensor electrode (15), configured to conclude that a pinch event is imminent if said difference exceeds a defined threshold and said duration detected for said sensor electrodes (3) deviates from a defined standard duration or from a standard duration detected in a state in which a pinch event is detected as not imminent, The device (1), characterized in that

2. 2. The device (1) according to claim 1, further characterized in that the control device (5) is configured to periodically stagger the charging and discharging processes of the sensor electrode (3) and the reference sensor electrode (15) so that the charging and discharging processes of the sensor electrode (3) start after the charging and discharging processes of the reference sensor electrode (15) have ended or vice versa.

3. - said sensor electrode (3) is arranged on the inner sealing lip of said sealing element (10); - said reference sensor electrode (15) is arranged on the outer sealing lip of said sealing element (10); Device (1) according to claim 1 or 2, characterized in that

4. - said control device (5) and said sensor electrode (3) are connected to a first measuring pin (6); - said control device (5) and said reference sensor electrode (15) are connected to a second measuring pin (16); - said control device (5) is connected to a first control pin (8), said sensor electrode (3) being connected to said first control pin (8) via a high impedance electrical resistor (7); - said control device (5) is connected to a second control pin (18), said reference sensor electrode (15) being connected to said second control pin (18) via a high impedance electrical resistor (17); said control device (5) - applying said potentials to said sensor electrode (3) and to said reference sensor electrode (15) via said first control pin (8) and said second control pin (18), respectively; - measuring simultaneously with the first measuring pin (6) the potential of the sensor electrode (3) and the distribution of negative charges on the sensor electrode (3), - measuring simultaneously with the second measuring pin (16) the potential of the reference sensor electrode (15) and the distribution of negative charges on the reference sensor electrode (15); - as soon as the potential measured at the measuring pins (6, 16) reaches a respective defined threshold, applying the ground potential (GND) to the control pins (8, 18), which causes charges to flow back from the sensor electrode (3) and the reference sensor electrode (15); - configured to detect the time taken for the potential of the sensor electrode (3) and the reference sensor electrode (15) to reach the threshold value and then reach a minimum threshold value caused by the backflow of charge, Device (1) according to any one of claims 1 to 3, characterized in that it

5. 5. The device (1) according to claim 1, characterized in that the sensor electrode (3) and the reference sensor electrode (15) are connected to the ground potential (GND) via electric capacitors (9, 19), respectively.

6. 6. The device (1) according to claim 1, wherein the sensor electrode (3) and the reference sensor electrode (15) are configured as a sensor cable having an electrical conductor (3.1, 15.1) and an electrical insulator (3.2, 15.2) surrounding it.

7. 7. The device (1) according to claim 1, characterized in that a shield electrode (13) for shielding the sensor electrode (3) and the reference sensor electrode (15) against occurring interferences is arranged in a frame element of the vehicle or in a roof bar of the vehicle at least partially surrounding the opening (O).

8. 2. The device (1) according to claim 1, characterized in that the control device (5) is further configured to conclude that a pinching event is imminent if, during the actuation of the closing movement of the closing element (4), the closing element (4) is found to be in a defined danger area (K).

9. A method for operating a device (1) according to any one of claims 1 to 8, comprising the steps of: - during the charging process, the potential is applied to the sensor electrode (3) and the reference sensor electrode (15), during the discharging process, the ground potential (GND) is applied to the sensor electrode (3) and the reference sensor electrode (15), the time required for the potential of the sensor electrode (3) and the reference sensor electrode (15) to reach a minimum threshold caused by the backflow of charges due to the ground potential (GND) is detected, the difference between the time taken for the sensor electrode (3) and the time taken for the reference sensor electrode (15) is calculated, - if said difference exceeds a defined threshold value and said duration detected for said sensor electrode (3) deviates from a defined standard duration or from a standard duration detected in a state where a pinch event is detected as not imminent, it is concluded that a pinch event is imminent; The method.

10. 1. A device for avoiding a pinch event in a motor operated closing system of a vehicle (2), comprising: - a device (1) for detecting a pinching event according to any one of claims 1 to 8, at least one control device for controlling the motor drive of said closure element (4), wherein the control device is configured to stop and / or reverse a closing movement of the closure element (4) if a pinching event is imminent.

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