Detecting and preventing a trapping event

A method for detecting a trapping event of a motor-actuatable closing system of a vehicle using a device comprising a sensor electrode and a reference sensor electrode, wherein the sensor electrode at least partially surrounds an edge of a vehicle opening closable by a closure element, wherein the sensor electrode is arranged in a sealing element at least partially surrounding the opening, wherein the reference sensor electrode at least partially surrounding the edge of the opening of the vehicle, wherein the reference sensor electrode is arranged spaced apart from the sensor electrode in the sealing element and has a greater spacing from the opening than the sensor electrode, the method comprising:

• applying an electrical potential to the sensor electrode for a charging process and to apply a ground potential to the reference sensor electrode for a discharging process,
• detecting, for the charging process, a first period of time until a first minimum threshold for an electrical potential for the sensor electrode is reached;
• detecting, for the discharging process, a second period of time until a second minimum threshold for an electrical potential for the reference sensor electrode is reached, wherein the first and second minimum thresholds are produced by a back flow of charges across the ground potential;
• determining a difference between the first and second periods of time detected, and
• inferring that a trapping event is imminent if the determined difference between the first and second periods of time exceeds a predefined threshold and if the first period of time detected for the sensor electrode deviates from a predefined standard period of time or deviates from a standard period of time detected in a state that has been detected without an imminent trapping event.

A device for preventing a trapping event of a motor-actuatable closing system of a vehicle, the device comprising:

• a device for detecting a trapping event of a motor-actuatable closing system of a vehicle, the device for detecting comprising
• a sensor electrode at least partially surrounding an edge of a vehicle opening closable by a closure element, wherein the sensor electrode is arranged in a sealing element at least partially surrounding the opening;
• a reference sensor electrode at least partially surrounding the edge of the opening of the vehicle, wherein the reference sensor electrode is arranged spaced apart from the sensor electrode in the sealing element and has a greater spacing from the opening than the sensor electrode;
• and
• a control unit configured to
• apply an electrical potential to the sensor electrode for a charging process and to apply a ground potential to the reference sensor electrode for a discharging process,
• detect, for the charging process, a first period of time until a first minimum threshold for an electrical potential for the sensor electrode is reached, and detect, for the discharging process, a second period of time until a second minimum threshold for an electrical potential for the reference sensor electrode is reached, wherein the first and second minimum thresholds are produced by a back flow of charges across the ground potential,
• determine a difference between the first and second periods of time detected, and
• infer that a trapping event is imminent if the determined difference between the first and second periods of time exceeds a predefined threshold and if the first period of time detected for the sensor electrode deviates from a predefined standard period of time or deviates from a standard period of time detected in a state that has been detected
• without an imminent trapping event;
• and
• a further control unit configured to control, responsive to inferring that the trapping event is imminent, a motor drive of the closure elements to stop reverse a closing movement of the closure element.