Procedure for the operation of a braking device for motor vehicles and braking device

Abstract

Method for operating a braking device (1) for motor vehicles, in particular for commercial vehicles, wherein the air pressure is detected along a trailer supply line (10.1) for venting a parking brake of a trailer and a trailer control line (10.2) for venting a service brake of a trailer by means of at least one first pressure sensor (8.1) and transmitted in the form of an electrical signal to an electronic control unit (3) of the motor vehicle, so that in the event of a faulty pressure change behavior an open trailer supply line (10.1) and / or an open trailer control line (10.2) is detected.

Description

[0001] The invention relates to a method for operating a braking device for motor vehicles, in particular for commercial vehicles, wherein the air pressure along a trailer supply line and / or a trailer control line is detected by means of at least one first pressure sensor and transmitted in the form of an electrical signal to an electronic control unit of the motor vehicle. Furthermore, the invention relates to a braking device for motor vehicles, in particular for commercial vehicles.

[0002] Parking brakes (also called handbrakes) of commercial vehicles, including trailers and rail vehicles, are now regularly equipped with spring brake cylinders which, in the release position, pressurise a spring compression chamber with compressed air and thus keep the spring tensioned, while for parking braking the spring compression chamber is vented, i.e. connected to atmospheric pressure, so that the brake cylinder generates a braking force under the action of the spring (cf. Bosch, Automotive Handbook, 22nd edition, Düsseldorf, 1995, p. 648).

[0003] Known methods for determining the coupling state of a truck with an electro-pneumatic braking system, as disclosed in DE 42 00 302 C2, are limited to the analysis of the temporal course of a pressure increase in a pressure line.

[0004] From DE 199 55 798 A1 a device for trailer detection is also known, whereby this device detects whether the pneumatic pressure hoses are connected to the towing vehicle or not.

[0005] For the proper operation of a braking system, it is essential that the electric parking brake can be released automatically. Such automatic parking brake release is particularly desirable in stop-and-go traffic or similar applications. However, without a quick check for the presence of a trailer or the coupling status of a trailer, the parking brake release process may be delayed and aborted, resulting in a significant loss of pressure.

[0006] It is therefore the object of the present invention to advantageously further develop a method for operating a braking device of the type mentioned above, in particular to the extent that a braking device can be monitored comparatively easily and quickly with regard to pressure conditions, so that proper operation of the braking device can be ensured. Furthermore, it is the object of the present invention to further develop a braking device in such a way, in particular to the extent that the braking device has a simple design and simultaneously enables comprehensive monitoring of the system.

[0007] This object is achieved according to the invention by a method having the features of claim 1 and a braking device having the features of claim 8. According to this method, a method for operating a braking device for motor vehicles, in particular for commercial vehicles, is provided, wherein along a trailer supply line for ventilating a parking brake of a trailer and / or a trailer control line for ventilating a service brake of a trailer, the air pressure is detected by means of at least one first pressure sensor and transmitted in the form of an electrical signal to an electronic control unit of the motor vehicle, so that in the event of a faulty pressure change behavior, an open trailer supply line and / or an open trailer control line is detected.

[0008] The invention is based on the basic idea that the method can be used to monitor the braking device of motor vehicles during operation, preferably automatically, in particular by means of the electronic control unit and at least one pressure transducer or pressure sensor.

[0009] For this purpose, a pneumatic pressure can preferably be detected at an output of the preferably pneumatic braking device, in particular at a trailer coupling.

[0010] In this sense, in the event of a faulty pressure change behavior, an open trailer supply line and / or an open trailer control line is automatically detected.

[0011] It is thus possible that a faulty coupling state between the towing vehicle and the trailer is detected, in particular independently, by the system, in particular the electronic control unit in conjunction with the at least one first pressure sensor.

[0012] If necessary, the system, in particular the electronic control unit, can automatically initiate appropriate countermeasures or protective measures.

[0013] In particular, the automatic monitoring of the condition of the braking system of the motor vehicle or the coupling with the trailer can be triggered by various types of electrical signals.

[0014] Among other things, data relating to the vehicle condition of the motor vehicle, such as the position of the accelerator pedal or the clutch pedal, transmission information, vehicle speed, distance information to other road users or the like, as well as any combination of such information, can be processed and used by the electronic control unit to trigger an automatic check of the operational capability of the braking system.

[0015] It is also possible for the electronic control unit to carry out a manually triggered check of the operational readiness of the motor vehicle by sending a corresponding input element or electrical signal to the electronic control unit via a manually operated smartphone, a touchscreen or other control elements.

[0016] Thus, using the electronic control unit and at least one first pressure sensor, it is possible to provide a variety of monitoring and control options for the operation of the motor vehicle or the braking system. Electronic monitoring of the coupling status for a trailer is also possible.

[0017] It is provided that along a trailer supply line for ventilating a parking brake of a trailer and a trailer control line for ventilating a service brake of a trailer, the air pressure is detected by means of at least one first pressure sensor and transmitted in the form of an electrical signal to an electronic control unit of the motor vehicle.

[0018] Preferably, the trailer supply line provides compressed air as needed to supply the parking brake of the coupled trailer.

[0019] Furthermore, it is preferably provided that the trailer control line provides compressed air as required to supply the service brake of the coupled trailer.

[0020] Thus, an air pressure or a pneumatic pressure change in the trailer supply line and / or the trailer control line can be detected and observed using at least one first pressure sensor.

[0021] A leak such as a faulty coupling condition of the trailer, due to which compressed air can escape from the trailer supply line and / or the trailer control line, can therefore preferably be detected automatically during operation.

[0022] Thus, in the event of a faulty pressure change behavior, an open trailer supply line and / or an open trailer control line is detected.

[0023] In addition, other technical problems in connection with the braking system can be detected, which lead to a deviating, in particular a faulty, pressure change behavior.

[0024] A pressure change behavior can generally be a change in pneumatic pressure in the form of a pressure increase or a pressure decrease, as well as a constant pneumatic pressure.

[0025] It can further be provided that the faulty pressure change behavior is detected if the measured air pressure deviates from a predeterminable pressure change threshold value within a predeterminable period of time.

[0026] In the sense of the present invention, a pressure change threshold can always also be a pressure change threshold range.

[0027] A pressure change threshold can be a threshold regarding an expected pressure increase, pressure decrease or constant pressure.

[0028] In particular, a pressure drop or pressure increase may occur within the specified period, causing the measured air pressure to deviate from a predefined, expected pressure change threshold or pressure change threshold range. In this case, an incorrect pressure change behavior is present.

[0029] An incorrect pressure change behavior therefore describes in particular a behavior of the pneumatic pressure within the brake system that does not move within expected, predetermined limits.

[0030] It can be provided that when the parking brake of the trailer is released and the trailer supply line and / or the trailer control line is torn off, there is a faulty pressure change behavior if the measured air pressure change corresponds to a pressure change value that is greater than the predeterminable pressure drop threshold value.

[0031] In particular, the pressure drop threshold may be an expected pressure drop threshold range.

[0032] The parking brake is released and thus pressurized with compressed air. If the trailer supply line and / or the trailer control line are broken or not properly connected to the trailer, a pressure drop will occur.

[0033] If this measured pressure change value of the pressure drop after the amount has been calculated exceeds the predefined pressure drop threshold or pressure drop threshold range, there is an incorrect pressure change behavior.

[0034] In terms of the absolute value of pressure change, a pressure drop after the mathematical absolute value has been calculated results in a positive pressure change value.

[0035] The absolute pressure change value describes the change in air pressure within a specified or specifiable period of time, in particular at at least two different points in time.

[0036] A measured change in air pressure thus results from at least two measured values ​​which are recorded at the beginning and at the end of a predetermined waiting time by means of the at least one first pressure sensor.

[0037] In particular, it can be provided that the detectable pressure change value can be calculated by means of a computational model independently of the vehicle-specific design of the pneumatic system.

[0038] It is also conceivable that the determination of a flow resistance of the trailer supply line or the trailer control line is possible at a low pneumatic pressure, for example between 100 and 500 mbar, so that in particular the volumes of the trailer's pneumatic lines are negligible.

[0039] Furthermore, it can be provided that in the case of the parking brake of the trailer being engaged, after the ventilation of the trailer supply line and / or the trailer control line and a trailer supply line or trailer control line not being connected, an incorrect pressure change behavior occurs if the measured air pressure change corresponds to a pressure change value that is smaller than the predeterminable pressure increase threshold value.

[0040] If the parking brake is engaged, the trailer supply line and / or the trailer control line are vented first. If the trailer supply line is not connected, an incorrect pressure change behavior can be detected if the measured air pressure change is smaller than the previously defined pressure increase threshold.

[0041] In this sense, the pressure increase threshold or pressure increase threshold range corresponds to an expected increase in air pressure.

[0042] In this way, in particular, an incorrect pressure change behavior in the trailer supply line due to a deviation from an expected pressure change threshold value or a pressure drop threshold value or a pressure increase threshold value can be determined.

[0043] A slow drop in pressure in the trailer control line and / or in the trailer supply line can also indicate an incorrect pressure change behavior and thus a malfunction of the braking system.

[0044] Furthermore, it can be provided that, in order to detect a faulty compressed air change behavior in the trailer control line, a pneumatic test pulse is generated by means of a first switching valve in connection with the trailer supply line and / or a pneumatic test pulse is generated along an inlet and an outlet of a second switching valve in connection with the trailer control line.

[0045] In this case, a predeterminable period of time or a predeterminable waiting time for recording pressure values ​​in an extended form can be provided in order to enable or take into account, in particular, switching of the second switching valve for recording measured values.

[0046] In particular, it can be provided that the input and the output of the second switching valve are connected to one another and the pneumatic test pulse can be generated by means of an inlet valve and / or a vent valve or by means of an electrical brake signal.

[0047] The first switching valve is preferably fluidly connected to the trailer supply line.

[0048] The second switching valve is preferably fluidly connected to the trailer control line.

[0049] A test pulse can be understood as a specific, definable compressed air pulse.

[0050] In particular, a pneumatic test pulse in the form of a compressed air pulse can be used to detect a compressed air change behavior in the trailer control line by means of the at least one first compressed air sensor.

[0051] Preferably, a coupling can be provided between the trailer supply line and the second switching valve so that an air pressure can be used to control the second switching valve.

[0052] A pneumatic test pulse or a compressed air pulse can be generated along the trailer control line, in particular through the inlet valve and / or a vent valve or by means of an electrical brake signal.

[0053] In this sense, the inlet valve and the vent valve are preferably fluidly connected to the second switching valve.

[0054] Furthermore, a brake pedal can be provided and actuated to generate an electrical brake signal in order to trigger a pneumatic test pulse along the compressed air control line.

[0055] Furthermore, it can be provided that the first switching valve is provided in connection with the trailer supply line, which is switched to the venting state by means of the control unit if a faulty pressure change behavior is detected in the trailer supply line and / or the trailer control line.

[0056] In general, and particularly independent of the application of a test pulse to detect faulty pressure change behavior in the trailer control line, the first switching valve can be switched to the venting state if faulty pressure change behavior is detected in the trailer supply line and / or the trailer control line.

[0057] In particular, a protective function is provided for the braking system so that a parking brake of the trailer is automatically vented and applied as soon as an incorrect pressure change behavior is detected.

[0058] Preferably, a coupling between the compressed air supply line and the second switching valve can be provided for this purpose such that the second switching valve is controlled in conjunction with the compressed air control line as a function of the air pressure in the trailer supply line.

[0059] Preferably, an electrical connection is further provided between the electronic control unit and the first switching valve.

[0060] The electronic control unit can switch the first switching valve to the venting state as needed if an incorrect pressure change behavior is detected in the trailer supply line and / or in the trailer control line.

[0061] By switching the first switching valve, in particular into a venting state, the trailer supply line is vented.

[0062] A malfunction, such as a leak, can be detected by means of at least one first pressure sensor as soon as an unexpected change or an unexpected lack of change in the air pressure in the trailer supply line and / or in the trailer control line is detected.

[0063] Depending on the air pressure in the trailer supply line, the second switching valve is switched to a separated state or to a pass-through state using the coupling line.

[0064] A protection function of the towing vehicle against a loss of pressure and a related loss of braking power is available using the second switching valve.

[0065] In this sense, the second switching valve can be designed as a shut-off valve, in particular in the form of a towing vehicle protection valve.

[0066] Preferably, the method for detecting a faulty pressure change behavior in conjunction with, for example, a start-up detection can be triggered or initiated by the electronic control unit, preferably automatically triggered.

[0067] Thus, a compressed air change behavior along the trailer supply line and / or the trailer control line can preferably be observed and monitored automatically with the aid of the at least one first compressed air sensor and the electronic control unit.

[0068] In a secondary aspect, a braking device for motor vehicles, in particular for commercial vehicles, is provided.

[0069] The braking device is provided with at least one compressed air connection, an electronic control unit, at least one input element, at least one first switching valve, at least one first pressure sensor and a first trailer coupling unit and a second trailer coupling unit.

[0070] The electronic control unit is connected, in particular electrically connected, to the input element, a control input of the first switching valve and the first pressure sensor.

[0071] A trailer supply line is provided such that an output of the first switching valve is connected to the first trailer coupling unit.

[0072] Furthermore, a trailer control line is provided and the first pressure sensor is connected to the trailer supply line and / or the trailer control line.

[0073] The input element is preferably provided as an electrical input signal, which in particular can fulfill the usual function of a switch for triggering a switching signal.

[0074] In particular, the input element can be triggered as an electrical signal by a start detection or other data of the motor vehicle resulting from the operating state of the motor vehicle.

[0075] In this way, data from a variety of sensors in a motor vehicle as well as from the field of autonomous driving can be processed, for example distances to other road users, in order to trigger an input element in the form of an electrical signal as needed.

[0076] Alternatively, the input element can be considered as an input switch for manual or automatic operation.

[0077] In particular, if manual operation of the input switch is provided, the input element can be designed in the form of a smartphone, a touchscreen or a comparable component.

[0078] The braking device can be connected to any compressed air source via the compressed air connection.

[0079] Both the supply of treated compressed air and the supply of fresh compressed air and adequate compressed air treatment within the braking system are conceivable.

[0080] In the sense of the present invention, a pressure sensor can be designed as a sensor, a (pressure) switch or a comparable element for the qualitative or quantitative detection or recognition, in particular of a pneumatic pressure in a compressed air line.

[0081] A trailer supply line is provided such that an output of the switching valve is connected to the first trailer coupling unit. The first trailer coupling unit is intended, in particular, for coupling to a parking brake of the trailer.

[0082] A trailer control line is provided such that an output of the second switching valve is connected to the second trailer coupling unit. The second trailer coupling unit is intended, in particular, for coupling to a service brake of the trailer.

[0083] The braking device according to the invention is based on the basic idea that, by means of an electronic control unit and at least one pressure sensor, a plurality of monitoring and control options for the operation of the motor vehicle or the braking device can be provided, in particular a monitoring of the coupling state for a trailer and a towing vehicle protection function.

[0084] This enables electronic monitoring of the coupling status for a trailer as well as a towing vehicle protection function.

[0085] In this sense, a motor vehicle, in particular a commercial vehicle, is preferably understood to mean a towing vehicle with at least one trailer.

[0086] By means of the electronic control unit, electrification in the sense of the braking device according to the invention is available, so that additional functionalities can be provided compared to conventional, in particular primarily manually controllable, braking systems.

[0087] Additional functionalities may include monitoring the proper operation of the braking system, automated control in various operating modes such as stop-and-go operation or delivery operation, as well as protective functions in the event of failure or malfunction of individual parts of the braking system.

[0088] This not only allows monitoring the coupling status of a towing vehicle with a trailer, but also allows automatic or semi-automatic activation of protective mechanisms in the event of malfunctions affecting the coupling mechanism.

[0089] An integration or combined design of the braking device according to the invention can be provided in conjunction with an air treatment device, an electric parking brake, an electronic braking system or an anti-lock braking system.

[0090] In particular, it can be provided that the at least one first pressure sensor is an external pressure sensor which is pneumatically and electrically connected to the braking device, preferably to a parking braking device.

[0091] According to the present invention, the at least one first pressure sensor can be electrically integrated into a parking brake system, wherein a pneumatic connection to the trailer supply line or the trailer control line is provided.

[0092] Furthermore, the first pressure sensor can also be provided as an external pressure sensor which is electrically and pneumatically connected to the parking brake or the braking device.

[0093] The electronic control unit is connected to the input element, a control input of the switching valve and the first pressure sensor.

[0094] Preferably, the control unit is electrically connected to the various components of the braking device in order to be able to process a large number of data, such as switch and valve positions as well as measured values ​​from sensors.

[0095] The control unit represents a central control means for receiving, processing and transmitting data or signals, in particular for the automatic or semi-automatic control of the braking device.

[0096] A trailer supply line is provided such that an output of the first switching valve is connected to the first trailer coupling unit.

[0097] In this way, the first trailer coupling unit can be ventilated, i.e. supplied with compressed air, or vented depending on the switching state of the first switching valve.

[0098] Compressed air can thus be provided for a parking brake, in particular a spring-loaded parking brake, of a trailer on the first trailer coupling unit.

[0099] The first switching valve can be provided in particular as an electrically controllable, bistable switching valve.

[0100] It is further provided that the braking device has a second switching valve, wherein the trailer control line is provided such that an output of the second switching valve is connected to the second trailer coupling unit.

[0101] The second switching valve can be designed, among other things, as a shut-off valve, in particular a towing vehicle protection valve.

[0102] Basically, the task of the second switching valve is to provide a pneumatic connection to the second trailer coupling unit as needed.

[0103] The first pressure sensor can be connected to the output of the first switching valve or to the output of the second switching valve.

[0104] A trailer control line is provided such that an output of the second switching valve is connected to the second trailer coupling unit.

[0105] In particular, compressed air can be provided to the second trailer coupling unit for a service brake of the trailer using the trailer control line.

[0106] The second switching valve may be provided as a component of the towing vehicle protection valve.

[0107] Using the second switching valve, a connection to the trailer control line can be interrupted if, for example, an unwanted pressure loss or a leak occurs in the trailer supply line.

[0108] In this way, an air pressure or a pressure change behavior, i.e. a change in the air pressure, in the trailer supply line and / or in the trailer control line can be measured or monitored.

[0109] In the context of the present invention, a pressure change behavior is to be understood in particular as meaning that, depending on the intended use of the trailer supply line or the trailer control line, a specific behavior of the air pressure is to be expected during operation of the braking device.

[0110] Accordingly, deviations from the expected pressure change behavior indicate a leak or other faults in the pneumatic circuit, in particular the trailer supply line and / or the trailer control line.

[0111] An expected pressure change behavior can be both the change of an air pressure and the maintenance of a certain air pressure during operation.

[0112] An incorrect pressure change behavior in the trailer supply line can be understood as meaning that no fluid pressure or air pressure can be generated in the trailer supply line or that an existing fluid pressure in the trailer supply line drops or rises unexpectedly.

[0113] For example, there may be an incorrect pressure change behavior in the trailer supply line if a trailer is to be connected to the first trailer coupling unit and no air pressure can be built up in the trailer supply line.

[0114] This means that the coupling status between the towing vehicle and the trailer can be determined or monitored.

[0115] A leak or other irregular pressure change behavior in the trailer supply line, e.g. an unexpected pressure drop, can also be detected in this way, whereby protective measures can then preferably be initiated by means of the control unit.

[0116] Alternatively, the first pressure sensor can be provided in the trailer control line in connection with the output of the second switching valve in order to be able to determine a pressure change behavior at the second trailer coupling unit.

[0117] For example, an incorrect pressure change behavior in the trailer control line means that an expected pressure change at the inlet of the second switching valve between the outlet of the second switching valve and the second trailer coupling unit cannot be detected or that an unexpected pressure change can be detected.

[0118] The expected pressure change can be derived from the operation of control elements such as a brake pedal or an electrical brake signal and processed in the control unit.

[0119] The air pressure or the pressure change behavior in the trailer supply line or the trailer control line can be monitored in this way in order to detect a possible malfunction by means of the control unit and to initiate protective measures, for example by switching valves.

[0120] Furthermore, a coupling line is provided so that the trailer supply line is connected to a control input of the second switching valve.

[0121] The second switching valve can be switched depending on the air pressure or fluid pressure in the trailer supply line.

[0122] In the event of a drop in air pressure in the trailer supply line, the second switching valve is preferably switched to a disconnected state so that there is no connection between the inlet and the outlet of the second switching valve.

[0123] In this way, the trailer control line can be protected from an unexpected drop in air pressure in the event of a leak in the trailer supply line.

[0124] In addition to determining and checking the coupling state between the towing vehicle and the trailer, a towing vehicle protection function can also be provided by means of the braking device according to the invention.

[0125] Furthermore, it can be provided that the at least one first pressure sensor is provided in connection with an output of the first switching valve and at least one second pressure sensor is provided in connection with an output of the second switching valve.

[0126] In this sense, the braking device according to the invention can be designed with at least two pressure sensors, wherein a pressure change behavior in the trailer supply line and in the trailer control line can be determined independently of one another.

[0127] This allows, for example, a leak or malfunction in both the trailer supply line and the trailer control line to be reliably detected. All that's required is the use of a second pressure sensor in conjunction with the control unit.

[0128] Furthermore, the coupling state of the first trailer coupling unit and the second trailer coupling unit can also be determined.

[0129] Alternatively, it should be taken into account that when using a single first pressure sensor on the trailer control line, a leak or similar in the trailer supply line can also be detected.

[0130] Due to the coupling line and the resulting dependence of the switching state of the second switching valve on the air pressure in the trailer supply line, an incorrect pressure change behavior in the trailer supply line also causes a detectable deviation from the expected pressure change behavior in the trailer control line.

[0131] It can further be provided that at least one input element is provided in connection with the electronic control unit, so that the first switching valve can be switched by means of the input element, in particular can be switched electrically.

[0132] In the sense of electrification of the control of a braking system, a convenient and versatile automation or semi-automation can be implemented in this way.

[0133] For example, by actuating the input element in the form of a user input or by generating an input element as an electrical signal based on, for example, a start-up detection, a parking brake can be ventilated or vented by means of the first switching valve.

[0134] Alternatively, other functionalities of the input element can be implemented or conceivable using the centrally provided electronic control unit.

[0135] Furthermore, an inlet valve can be provided such that the inlet of the second switching valve is connected or connectable to an outlet of the inlet valve.

[0136] An inlet of the inlet valve can be connected or connectable in particular to the compressed air connection directly or indirectly, i.e. via other components of the pneumatic circuit, so that compressed air can be provided via the inlet valve.

[0137] In this way, compressed air can be supplied to the inlet of the second switching valve in a controlled manner via the inlet valve.

[0138] Furthermore, a vent valve may be provided such that an inlet of the vent valve is connected to the outlet of the inlet valve.

[0139] The inlet of the vent valve, like the inlet of the inlet valve, is connected or connectable to the inlet of the second switching valve.

[0140] Thus, the air pressure at the inlet of the second switching valve can be specifically adjusted or controlled by means of the inlet valve and the vent valve.

[0141] In addition, a stretch brake unit can be provided in conjunction with the electronic control unit, so that the inlet valve can be electrically switched via a control input and the vent valve can be electrically switched via a control input by means of the control unit.

[0142] In this sense, an anti-theft braking unit is provided to provide anti-theft braking functionality for the motor vehicle.

[0143] Using such an anti-drag brake unit, in particular for controlling the inlet valve and the vent valve by means of the control unit, compressed air can be specifically supplied via the second switching valve of the second trailer coupling unit for a service brake of the trailer.

[0144] By braking the trailer, preferably in stages, the vehicle can be stretched and thus stabilized.

[0145] Further details and advantages of the invention will now be explained with reference to an embodiment shown in more detail in the drawing.

[0146] It shows: Fig. 1 an embodiment of a braking device for motor vehicles with a first and second pressure sensor.

[0147] In Fig. 1 shows an embodiment of a braking device 1 for motor vehicles with a compressed air connection 2 and an electronic control unit 3.

[0148] Compressed air can be supplied to the braking device 1 via the compressed air connection 2 in order to be further used for the braking device 1, preferably after compressed air treatment to remove oil and moisture from the compressed air.

[0149] In particular, the compressed air connection 2 can be connected to any compressed air source.

[0150] Furthermore, the electronic control unit 3 represents a central control means. The control unit 3 is electrically connected to the other components of the braking device 1, such as valves, sensors, switches or other input elements 4.

[0151] In this sense, an input element 4 can be understood as a sensor, switch or the like, in particular as an electrical signal from the sensor, switch or the like to the electronic control unit 3, so that automatic monitoring of the braking device can be triggered as needed.

[0152] All signals and data can be fed to the control unit 3, processed in the control unit 3 and resulting control commands can be forwarded to at least one of the components of the braking device 1.

[0153] Furthermore, according to Fig. 1 shows an input element 4 and a first switching valve 5 with an inlet 5a, an outlet 5b, a control inlet 5c and a vent outlet 5d.

[0154] The input element 4 is electrically connected to the control unit 3.

[0155] The first switching valve 5 is connected to the control unit 3 via the control input 5c.

[0156] Thus, the input element 4 can be used via the control unit 3 to switch the first switching valve 5.

[0157] The first switching valve 5 is according to Fig. 1 as a spring-loaded 3 / 2-way valve such that the output 5b is connected to the vent output 5d.

[0158] In particular, the first switching valve 5 can be provided as a bistable switching valve.

[0159] Furthermore, the braking device 1 has a first trailer coupling unit 9.1 and a second trailer coupling unit 9.2.

[0160] The first trailer coupling unit 9.1 is connected to the output 5b of the first switching valve 5 via a trailer supply line 10.1.

[0161] According to the switching state of the first switching valve 5 in Fig. 1, the trailer supply line is vented via the vent outlet 5d of the first switching valve 5.

[0162] Preferably, compressed air for ventilating a parking brake or spring-loaded parking brake of a trailer can be provided via the trailer supply line 10.1 on the first trailer coupling unit 9.1.

[0163] Furthermore, in Fig. 1 shows a second switching valve 7.

[0164] In particular, the second switching valve 7 in the sense of Fig. 1 in the form of a towing vehicle protection valve 6.

[0165] The second switching valve 7 has an inlet 7a, an outlet 7b and a control inlet 7c.

[0166] The inlet 7a of the second switching valve 7 is indirectly connected to the compressed air connection 2 via various pneumatic circuit components in such a way that, for example, by actuating a brake pedal, compressed air, in particular treated compressed air, can be supplied to the inlet 7a of the second switching valve.

[0167] The output 7b of the second switching valve 7 is connected to the second trailer coupling unit 9.2 via a trailer control line 10.2 in order to supply it with compressed air.

[0168] The second trailer coupling unit 9.2 can be provided in particular for providing compressed air for a service brake of a trailer.

[0169] According to Fig. 1, the second switching valve 7 is designed as a spring-loaded and normally closed or separated 2 / 2-way valve. In this sense, a connection is established between the inlet 7a and the outlet 7b of the second switching valve 7 in the switching state according to Fig. 1 separated.

[0170] The control input 7c of the second switching valve 7 is connected via a coupling line 12 to the trailer supply line 10.1 and the output 5b of the first switching valve 5.

[0171] Thus, switching of the second switching valve 7 can be effected by changing the air pressure or the fluid pressure in the trailer supply line 10.1.

[0172] In this sense, a pressure drop in the trailer supply line 10.1 or at the outlet 5b of the first switching valve 5 can lead to the second switching valve 7 being switched from a permeable switching position to the Fig. 1 shown, separate switching position.

[0173] According to Fig. 1, the switching position of the second switching valve 7 is coupled to the air pressure or the fluid pressure in the trailer supply line 10.1.

[0174] In addition, the braking device 1 is Fig. 1 with a first pressure transducer or pressure sensor 8.1 and a second pressure transducer or pressure sensor 8.2.

[0175] The first pressure sensor 8.1 is electrically connected to the control unit 3 and the trailer supply line 10.1, ie the first pressure sensor 8.1 detects the air pressure in the trailer supply line 10.1, at the output 5b of the switching valve 5 or at the first trailer coupling unit 9.1.

[0176] The second pressure sensor 8.2 is electrically connected to the control unit 3 and the trailer control line 10.2, ie the second pressure sensor 8.2 detects the air pressure in the trailer control line 10.2, at the output 7b of the second switching valve 7 or at the second trailer coupling unit 9.2.

[0177] By means of the first and second pressure sensors 8.1; 8.2, it can be determined whether a suitable air pressure for operating the motor vehicle is present in the trailer supply line 10.1 and / or the trailer control line 10.2.

[0178] In particular, the coupling state between the towing vehicle and the trailer at the first and second trailer coupling units 9.1; 9.2 can be derived from the air pressures in the trailer supply line 10.1 and the trailer control line 10.2.

[0179] This function can be understood as a trailer detection function.

[0180] If the first pressure sensor 8.1 in the trailer supply line 10.1 detects the air pressure or the pressure change behavior and the control unit 3 detects an incorrect pressure change behavior, suitable protective measures can be initiated by the control unit 3, for example.

[0181] The same applies in the event that the control unit 3 derives an incorrect pressure change behavior from the measured values ​​of the second pressure sensor 8.2 concerning the air pressure in the trailer control line 10.2.

[0182] If, during operation of the braking device 1 in a motor vehicle, an air pressure in the trailer supply line 10.1 drops unexpectedly, the second switching valve 7 is simultaneously switched over via the coupling line 12 at the control input 7c of the second switching valve 7.

[0183] This can be understood as a towing vehicle protection function, whereby a potentially possible pressure loss in the trailer control line 10.2 is prevented by switching the second switching valve 7 in the event of a pressure loss in the trailer supply line 10.1.

[0184] Furthermore, an incorrect pressure change behavior in the trailer supply line 10.1 may occur, for example, in the event of an unexpected pressure drop or if no pressure build-up or no sufficient pressure build-up can be detected in the trailer supply line 10.1 after the motor vehicle has been put into operation and the trailer is coupled.

[0185] Faulty pressure change behavior in the trailer control line can occur if a brake pulse, which is also present in particular at an input 7a of the second switching valve 7, cannot be detected in the trailer control line 10.2.

[0186] Likewise, a slowly decreasing air pressure in the trailer control line 10.2 can indicate a leak or a faulty pressure change behavior, in response to which the control unit 3 can initiate appropriate countermeasures or protective measures.

[0187] In this sense, the electrical connection of the electronic control unit 3 with the components of the braking device 1 or of the motor vehicle is necessary so that the control unit 3 can compare data about, for example, the switching state of the valves as well as about the other components with the measurement data of the first and / or second pressure sensor 8.1; 8.2 and can determine an incorrect pressure change behavior.

[0188] According to Fig. 1 further shows an extension brake unit 11 in the sense of a further input element 4, i.e. as a source of an electrical signal to the control unit 3, and in electrical connection with the control unit 3.

[0189] In addition, Fig. 1 an inlet valve 11.1 and a vent valve 11.2, which can be controlled via the control unit 3, preferably by means of the extension brake unit 11.

[0190] For this purpose, a control input 11.1c of the inlet valve 11.1 and a control input 11.2c of the vent valve 11.2 are electrically connected to the control unit 3.

[0191] The inlet valve 11.1, as a normally separated 2 / 2-way valve, also has an inlet 11.1a and an outlet 11.1b.

[0192] The inlet 11.1a is supplied with compressed air via the compressed air connection 2 and other components of the pneumatic circuit.

[0193] The outlet 11.1b of the inlet valve 11.1 is according to Fig. 1 is connected or connectable to the inlet 7a of the second switching valve 7 via a double check valve of the towing vehicle protection valve 6.

[0194] In the sense of a conventional double check valve, the connection between the outlet 11.1b of the inlet valve 11.1 and the inlet 7a of the second switching valve 7 can be at least temporarily interrupted or separated depending on the pressure conditions at the intermediate double check valve.

[0195] The vent valve 11.2 has a Fig. 1 spring-loaded, normally open 2 / 2-way valve has an inlet 11.2a and a vent outlet 11.2b.

[0196] The inlet 11.2a of the vent valve 11.2 is connected to the outlet 11.1b of the inlet valve.

[0197] Likewise, the inlet 11.2a of the vent valve 11.2 is connected or connectable to the inlet 7a of the second switching valve 7 via the intermediate double check valve of the towing vehicle protection valve 6.

[0198] Since the inlet valve 11.1 and the vent valve 11.2 can be controlled via the stretch brake unit 11 and the control unit 3, ventilation or venting of the inlet 7a of the second switching valve 7 can be specifically adjusted.

[0199] In particular, an anti-drag braking action to stabilize the motor vehicle can be activated by means of the anti-drag braking unit 11 and carried out in a controlled manner using the electronic control unit 3 by controlling the inlet valve 11.1 and the vent valve 11.2 as required.

[0200] Furthermore, it can be provided that, in particular with the inlet valve 11.1 and / or the vent valve 11.2, a test pulse can be applied to the inlet 7a of the second switching valve 7 in order to detect an expected pressure change behavior in the trailer control line 10.2.

[0201] In this sense, an electrification of the braking device 1 is achieved, inter alia, by the control unit 3 according to Fig. 1 scored.

[0202] Alternatively, deviating from Fig. 1, only the first pressure sensor 8.1 may be provided in the trailer supply line 10.1 or in the trailer control line 10.2. In this case, the second pressure sensor 8.2 is omitted without replacement.

[0203] If the first pressure sensor 8.1 is provided in the trailer supply line 10.1, a pressure change behavior in the trailer supply line 10.1 can be detected and, if necessary, switching of the switching valve 5 can be initiated via the control unit 3.

[0204] If the first pressure sensor 8.1 is provided in the trailer control line 10.2, a pressure change behavior can be detected in the trailer control line 10.2 as well as in the trailer supply line 10.1.

[0205] An incorrect pressure change behavior in the trailer supply line 10.1, in particular a slow pressure drop or an insufficient air pressure build-up during commissioning, causes the second switching valve 7 to have a separate switching state via the coupling line 12.

[0206] As a result, an incorrect pressure change behavior in the trailer control line 10.2 due to the separately switched second switching valve 7, e.g. when the service brake of the trailer is actuated, can be determined using the first pressure sensor 8.1 in the trailer control line 10.2.

[0207] In general, in this way, a preferably automatic monitoring of the braking device of a motor vehicle can be triggered by means of the electronic control unit 3 on the basis of at least one input element 4, in particular in the form of an electrical signal, e.g. a sensor, switch or the like in the context of a start-up detection. LIST OF REFERENCE SYMBOLS 1 braking device 2 compressed air connection 3 electronic control unit 4 Input element 5 Switching valve 5a Input of the switching valve 5b Output of the switching valve 5c Control input of the switching valve 5d Vent outlet of the switching valve 6 Towing vehicle protection valve 7 second switching valve 7a Input of the second switching valve 7b Output of the second switching valve 7c Control input of the second switching valve 8.1 first pressure sensor 8.2 second pressure sensor 9.1 first trailer coupling unit 9.2 second trailer coupling unit 10.1 Trailer supply line 10.2 Trailer control line 11 Stretch brake unit 11.1 Inlet valve 11.1a Inlet valve inlet 11.1b Outlet of the intake valve 11.2 Vent valve 11.2a Inlet of the vent valve 11.2b Outlet of the vent valve 12 Double check valve 13 Coupling line

Claims

[1] Method for operating a braking device (1) for motor vehicles, in particular for commercial vehicles, wherein the air pressure is detected by means of at least one first pressure sensor (8.1) along a trailer supply line (10.1) for ventilating a parking brake of a trailer and a trailer control line (10.2) for ventilating a service brake of a trailer and is transmitted in the form of an electrical signal to an electronic control unit (3) of the motor vehicle, so that in the event of a faulty pressure change behavior, an open trailer supply line (10.1) and / or an open trailer control line (10.2) is detected. [2] Method according to claim 1, characterized by that the faulty pressure change behavior is detected if the measured air pressure deviates from a predeterminable pressure change threshold value within a predeterminable period of time. [3] Method according to claim 1 or 2, characterized bythat when the parking brake of the trailer is released and the trailer supply line (10.1) and / or the trailer control line (10.2) is torn off, there is a faulty pressure change behavior if the measured air pressure change corresponds to a pressure change value which is greater than the predeterminable pressure drop threshold value. [4] Method according to one of the preceding claims, characterized by that in the case of the parking brake of the trailer being engaged, after the ventilation of the trailer supply line (10.1) and / or the trailer control line (10.2) and a trailer supply line (10.1) or trailer control line (10.2) not being connected, there is a faulty pressure change behavior if the measured air pressure change corresponds to a pressure change value which is smaller than the predeterminable pressure increase threshold value. [5] Method according to one of the preceding claims, characterized byin that, in order to detect a faulty compressed air change behavior in the trailer control line (10.2), a pneumatic test pulse is generated by means of a first switching valve (5) in connection with the trailer supply line (10.1) and / or a pneumatic test pulse is generated along an inlet (7a) and an outlet (7b) of a second switching valve (7) in connection with the trailer control line (10.2). [6] Method according to claim 5, characterized by that the inlet (7a) and the outlet (7b) of the second switching valve (7) are connected to one another and the pneumatic test pulse can be generated by means of an inlet valve (11.1) and / or a vent valve (11.2) or by means of an electrical brake signal. [7] Method according to claim 5 or 6, characterized bythat a first switching valve (5) is provided in connection with the trailer supply line (10.1), which is switched to the venting state by means of the control unit (3) when an incorrect pressure change behavior is detected in the trailer supply line (10.1) and / or the trailer control line (10.2). [8] Braking device (1) for motor vehicles, in particular for commercial vehicles, for operation according to a method according to one of the preceding claims, with at least one compressed air connection (2), an electronic control unit (3), at least one input element (4), at least one first switching valve (5), at least one first pressure sensor (8.1) and a first trailer coupling unit (9.1) and a second trailer coupling unit (9.2), wherein the electronic control unit (3) is connected to the input element (4), a control input (5c) of the first switching valve (5) and the first pressure sensor (8.1), wherein a trailer supply line (10.1) is provided such that an output (5b) of the first switching valve (5) is connected to the first trailer coupling unit (9.1), wherein a trailer control line (10.2) is provided, and wherein the first pressure sensor (8.1) is connected to the trailer supply line (10.1) and / or the trailer control line (10.2) is connected, . characterized by in that the braking device (1) has a second switching valve (7), wherein the trailer control line (10.2) is provided such that an output (7b) of the second switching valve (7) is connected to the second trailer coupling unit (9.2), wherein a coupling line (13) is provided such that the trailer supply line (10.1) is connected to a control input (7c) of the second switching valve (7). [9] Braking device (1) according to claim 8, characterized by that the at least one first pressure sensor (8.1) is provided in connection with an output (5b) of the first switching valve (5) and at least one second pressure sensor (8.2) is provided in connection with an output (7b) of the second switching valve (7). [10] Braking device (1) according to one of claims 8 or 9, characterized bythat the at least one input element (4) is provided in connection with the electronic control unit (3), so that the first switching valve (5) can be switched by means of the input element (4). [11] Braking device (1) according to one of claims 8 to 10, characterized by that an inlet valve (11.1) is provided such that the inlet (7a) of the second switching valve (7) is connected or connectable to an outlet (11.1b) of the inlet valve (11.1). [12] Braking device (1) according to claim 11, characterized by that a vent valve (11.2) is provided such that an inlet (11.2a) of the vent valve (11.2) is connected to the outlet (11.1b) of the inlet valve (11.1). [13] Braking device (1) according to claim 11 or 12, characterized bythat a stretch brake unit (11) is provided in conjunction with the electronic control unit (3), so that the inlet valve (11.1) can be electrically switched via a control input (11.1c) and / or the vent valve (11.2) can be electrically switched via a control input (11.2c) by means of the control unit (3).

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