Electronically controllable pneumatic braking system with a reversing relay valve for venting and venting a spring brake cylinder of a vehicle

Abstract

The invention relates to an electronically controllable pneumatic braking system for a vehicle, comprising at least a first service brake circuit with a first service brake pressure modulator and an electronic service brake control unit. Furthermore, the electronically controllable pneumatic braking system comprises a parking brake device. The parking brake device comprises a parking brake module and a reversing relay valve for venting and bleeding at least one first spring-loaded brake cylinder of the vehicle. The reversing relay valve has a first control port, a second control port, a working port, a supply port, and a vent port. The second control port is connected to an electro-pneumatic valve arrangement for receiving a second control pressure, wherein the electro-pneumatic valve arrangement is controlled by an electronic control unit that is independent of the electronic service brake control unit.The reversing relay valve is configured to vent the spring brake cylinder in the event that the first and second control ports are vented and a supply pressure is applied to the first supply port.

Description

The invention relates to an electronically controllable pneumatic brake system for a vehicle, in particular a commercial vehicle. The invention further relates to a method for controlling a vehicle, in particular a commercial vehicle, having an electronically controllable pneumatic brake system, a vehicle comprising such a brake system and a use of a reversing relay valve for supplying and venting a spring-loaded brake cylinder of a vehicle.Modern commercial vehicles frequently have an electropneumatic brake system. Spring-loaded brakes are part of the brake system as parking brakes. These are also referred to as parking brakes. The parking brakes act by spring force and can be released or fixed by venting spring-loaded brake cylinders. Within a service brake system, valves for regulating the service brake pressure are electronically activated. The valves can be provided in so-called axle modulators or outside the same. The axle modulators can be automated or partially automated and / or can be electronically controlled by an autonomous unit. The parking brakes are also controlled electronically. It is known in particular that the ventilation or venting of the spring-loaded brake cylinders is regulated by actuating a solenoid valve. The spring-loaded brake cylinders can be combined with service brake cylinders, so that the spring-loaded brake and the service brake act on the same brake pistons. In order to avoid a mechanical overload of the brake pistons by adding brake forces from the service brakes and the spring-loaded brakes, suitable structural measures can be taken. If the service brakes are actuated while the parking brakes are active, the spring-loaded brake cylinders are simultaneously ventilated in order to avoid the addition of the braking forces. Such a function is also referred to as an "anti-compound function".In electropneumatic brake systems for modern vehicles, safety concepts are of high relevance. In particular in the case of vehicles having automated or partially automated driving functions, braking functions must remain available at least to a limited extent even in the event of a fault or a power failure of a control unit. Only in this way can the safety of the vehicle, its occupants and further road users be guaranteed. For this purpose, it is known to provide redundancy levels which can still provide an at least limited braking function even in the event of failure of a primary system.A redundancy level is also desired for the parking brake, since vehicles can be safely parked only with the parking brake engaged in most cases. In order to expand the functionality and, in particular, independently of the occurrence of a fault in one of the various levels, be it the operating level or a redundancy level of the brake system, to be able to vent the corresponding spring-loaded cylinders of the parking brake and thus to be able to shut down the vehicle safely, it is desirable that the spring-loaded brake cylinders can be actuated via two independent paths in order to vent them. This is intended to increase the range of functions and the operational readiness of the vehicle in order to be able to ensure reliable parking of the vehicle even in the event of one or more faults in the brake system.DE 10 2021 122 497 A1 discloses a method for operating an electropneumatic brake system for a vehicle, wherein the brake system comprises a service brake system and a parking brake system, wherein the parking brake system comprises at least one spring brake cylinder. The method is characterized by the steps of: providing a control signal for holding a spring accumulator venting pressure venting the at least one spring accumulator brake cylinder by a control unit, interrupting the provision of the control signal in the event of a fault and / or a power failure and / or a diagnostic event of the control unit, thereby automatically ending the holding of the spring accumulator venting pressure for venting the at least one spring accumulator brake cylinder, thereby triggering a spring accumulator failure braking of the vehicle by the parking brake system, wherein the venting of the spring accumulator venting pressure takes place by a service brake venting function of the service brake system. The service brake venting function enables at least one venting path, which is opened in particular continuously or temporarily interrupted, in the service brake system for venting the at least one spring brake cylinder. The service brake venting function is implemented in particular by a valve in the service brake system, preferably an outlet valve and / or a further outlet valve.Further partially redundant systems are known from DE 10 2022 101 142 A1, DE 10 2021 122 498 A1, DE 10 2021 122 499 A1, DE 10 2020 132 875 A1 and EP 3 145 769 B1.Even if a redundant possibility for engaging a parking brake is already created by known systems, there is a need for further improvements. In particular, in the aforementioned known possibilities, assembly and production costs can be high, since the connection to the service brake system may require long line paths. In addition, the achievable system dynamics can be limited.It is therefore an object of the present invention to specify an electronically controllable pneumatic brake system having an improved parking brake device, which makes it possible to vent a spring-loaded brake cylinder easily and / or reliably even in the case of redundancy.The object is achieved by the features of the independent claims. Preferred embodiments are the subject of the dependent claims.In a first aspect of the invention, the object is achieved by an electronically controllable pneumatic brake system for a vehicle, in particular a commercial vehicle, according to claim 1. The electronically controllable pneumatic brake system has at least one first service brake circuit with a first service brake pressure modulator. The service brake pressure modulator has at least one first service brake pressure connection for controlling a service brake pressure for at least one first service brake actuator of the vehicle, wherein the service brake pressure modulator is connected to a first compressed air supply for receiving supply pressure. The electronically controllable pneumatic brake system also has an electronic service brake control unit which is connected to the service brake pressure modulator and provides primary switching signals at the latter for switching at least one electromagnetic valve of the first service brake pressure modulator. In addition, the electronically controllable pneumatic brake system has a parking brake device. The parking brake device comprises a parking brake module having a parking brake pressure port, wherein the parking brake module is configured to provide a parking brake pressure at the parking brake pressure port. In addition, the parking brake device comprises a reversing relay valve for supplying and venting at least one first spring-loaded brake cylinder of the vehicle. The reversing relay valve has a first control connection, a second control connection, a working connection, at least one first supply connection and a vent. The first control port is connected to the parking brake pressure port for receiving the parking brake pressure, the working port is connected to the spring brake cylinder, and the second control port is connected to an electropneumatic valve arrangement for receiving a second control pressure, wherein the electropneumatic valve arrangement is actuated by an electronic control unit which is independent of the parking brake module. The second control pressure is different from the service brake pressure and preferably independent thereof. The reversing relay valve is configured to vent the spring-loaded brake cylinder for a case in which the first control connection is vented, the second control connection is vented and a supply pressure is present at the first supply connection, and to vent the spring-loaded brake cylinder for a case in which the first and the second control connection are vented and a supply pressure is present at the first supply connection.The inventors have recognized that with a parking brake device which has, in addition to the parking brake module, a reversing relay valve, wherein the reversing relay valve has at least two control connections, the at least first spring-loaded brake cylinder can be vented in two ways which are independent of one another, in order thus to fix a parking brake associated with the first spring-loaded brake cylinder. It should be understood that the reversing relay valve can be controlled via the first control connection in a known manner, i.e. when a control pressure is present at the first control connection, the first spring-loaded brake cylinder is ventilated, and when no control pressure is present, the first spring-loaded brake cylinder is ventilated. The second control port, on the other hand, can be understood as a control port with an inverse function, i.e. by applying a second control pressure to the second control port, it can be achieved that the spring brake cylinder is ventilated even if the first control port is ventilated. The inventors have recognized that by interconnecting the second control port with an electro-pneumatic valve arrangement that is actuated by an electronic control unit that is independent of the parking brake module, the second control port can also be actuated in a case in which a fault occurs in the parking brake module, and thus the vehicle can be safely parked by venting the spring-loaded brake cylinder. The parking brake module, which can also be referred to as an electronic parking brake module, is to be regarded as a primary unit of the parking brake device, which is normally configured to fix the parking brake of the vehicle. Via the second control connection of the reversing relay valve, a possibility is created which is redundant to the parking brake module and which enables the parking brake to be fixed if a fault occurs in the parking brake module.In a preferred development, the reversing relay valve has a third control connection. The third control port is connected to the first service brake pressure port for receiving the service brake pressure. The reversing relay valve is configured to vent the spring brake cylinder for a case in which the first control connection and the third control connection are vented, the second control connection is vented or vented, and a supply pressure is present at the first supply connection, to vent the spring brake cylinder, and / or to vent the third control connection and a supply pressure is present at the first supply connection, to vent the spring brake cylinder for a case in which the second and the third control connections are vented, the first control connection is vented and a supply pressure is present at the first supply connection, to vent the spring brake cylinder. It should be understood that the third control connection of the reversing relay valve is provided and configured in particular to provide an anti-compound function. If the service brakes are actuated when the parking brake is fixed, i.e. when the spring-loaded brake cylinder is vented, the third control connection is charged or vented with the service brake pressure. By venting the third control connection, the first spring brake cylinder is ventilated and the associated parking brake is released. It should also be understood that the compressed air provided by the reversing relay valve to ventilate the spring brake cylinder is proportional to the service brake pressure provided at the third control port. Furthermore, it should be understood that a simultaneous application of service brake pressure at the third control connection and of a second control pressure at the second control connection has no influence on the anti-compound function of the reversing relay valve.Preferably, the service brake pressure modulator and the service brake electronic control unit are integrated in one module. It is preferred that the service brake pressure modulator and the electronic service brake control unit are shown as a structural unit. The service brake pressure modulator and the electronic service brake control unit are preferably units of a primary system of the electronically controllable pneumatic brake system. The service brake pressure modulator is preferably a rear axle operating brake pressure modulator, that is to say a service brake pressure modulator which is configured to control a service brake pressure for at least one first service brake actuator at a rear axle of the vehicle.The electropneumatic valve arrangement is preferably independent of a service brake function of the electronically controllable pneumatic brake system. The electro-pneumatic valve arrangement is preferably independent of the service brake system. Although the electropneumatic valve arrangement can receive supply pressure from a compressed air supply assigned to the service brake function, it is independent of pressures controlled by the service brake function. Preferably, the electropneumatic valve arrangement is also not actuated by an electronic control unit assigned to the service brake function.Furthermore, the electropneumatic valve arrangement is preferably bistable. This means that it has at least two stable switching positions and holds these switching positions in each case even if an energization is omitted. In the event of a fault, which leads to a failure of the voltage supply provided for the electropneumatic valve arrangement, the switching position of the electropneumatic valve arrangement does not change as a result of the omission, so that a previously possibly controlled pressure can remain controlled further even if the energization is omitted.The electropneumatic valve arrangement preferably has a relay valve with a relay valve supply connection, a relay valve working connection and a relay valve control connection. The relay valve working port is preferably connected to the second control port of the reversing relay valve. The electropneumatic valve arrangement preferably has a first electromagnetic switching valve which is configured to pass, with current, compressed air from the first compressed air supply to the relay valve control connection. It should be understood in this respect that a first input of the first electromagnetic switching valve is preferably connected to the first compressed air supply, and that a first output of the first electromagnetic switching valve is preferably connected to the relay valve control connection. The first electromagnetic switching valve is preferably controlled by the electronic control unit, which is independent of the parking brake module. The first electromagnetic switching valve may be a 2 / 2-way valve or a 3 / 2-way valve. If the first electromagnetic switching valve is now actuated or energized, the first electromagnetic switching valve switches into a position in which compressed air can flow from the first compressed air supply to the relay valve control connection, so that the relay valve is actuated. When the relay valve is actuated, it opens and opens a flow path between the relay valve supply port and the relay valve working port. The compressed air then reaches the second control terminal of the reversing relay valve as a second control pressure from the relay valve working terminal. The relay valve supply connection is preferably connected at least to the first compressed air supply.In a preferred development, the electropneumatic valve arrangement has a second electromagnetic switching valve. The second electromagnetic switching valve has a passage position and a venting position. Preferably, the second electromagnetic switching valve is de-energized in the open position and connects the relay valve working connection to the relay valve control connection in the open position. The second electromagnetic switching valve is thus preferably configured to provide a self-holding function for the relay valve. Consequently, in order to ventilate the second control connection of the reversing relay valve, the first electromagnetic switching valve does not have to be permanently energized. A brief energizing of the first electromagnetic switching valve is sufficient, after which the relay valve remains actuated on account of the self-holding function and in the open position, as a result of which the second control connection of the reversing relay valve remains aerated. Only when the second electromagnetic switching valve is activated or energized, it preferably switches into the venting position. In the venting position, the self-holding function of the relay valve is interrupted and the second control connection of the reversing relay valve is no longer vented. The second electromagnetic switching valve is preferably designed as a 3 / 2-way valve. The second electromagnetic switching valve is preferably controlled by the electronic control unit, which is independent of the parking brake module.Preferably, a dual supply check valve is arranged upstream of the relay valve supply connection, wherein a first dual supply check valve inlet is connected to the first compressed air supply, and a second dual supply check valve inlet is connected to a second compressed air supply. The first compressed air supply is preferably independent of the second compressed air supply. If the first compressed air supply is idle or empty, i.e. has a fault, for example, compressed air can continue to be provided from the second compressed air supply at the relay valve supply connection. The second compressed air supply can be a compressed air supply for a redundancy brake pressure modulator of the electronically controllable pneumatic brake system or another compressed air supply which is independent of the first compressed air supply.In a preferred development, the electropneumatic valve arrangement has a select-low valve and a pneumatically switchable valve with a pneumatic control connection. The pneumatically switchable valve preferably has a passage position and a venting position. The select-low valve preferably has a first select input, a second select input and a select output. The first select input is preferably connected to the pneumatically switchable valve, the second select input is preferably connected to the first electromagnetic switching valve, and the select output is preferably connected to the relay valve control connection. The pneumatically switchable valve is preferably configured to vent the first select input in response to a pneumatic control pressure at the pneumatic control port. It should be understood that the select-low valve is designed in such a way that the lower of the pressures present at the two select inputs is always output via the select output. The select-low valve is preferably configured to connect that select inlet to the select outlet at which the lower pressure is present. Thus, if no pressure is present at one of the two select inputs or at both select inputs, no pressure is present at the select output as well. If no pressure is present at the select output, no pressure is present at the relay valve control connection either, unless the self-holding function described above has been initiated beforehand. If no pressure is applied to the relay valve control port, the relay valve remains or switches to a closed position in which the flow path between the relay valve supply port and the relay valve working port is closed.The pneumatic control connection of the pneumatically switchable valve is preferably connected to the first service brake pressure connection or a brake pressure connection of a front axle brake pressure modulator or a brake pressure connection of a redundancy brake pressure modulator for receiving a pneumatic control pressure. If the service brakes are therefore actuated, the pneumatically switchable valve is actuated with a brake pressure either by the service brake pressure modulator, the front axle brake pressure modulator or the redundancy brake pressure modulator, wherein it should be understood that the brake pressures, by the service brake pressure modulator, the front axle brake pressure modulator and the redundancy brake pressure modulator, can have different pressure levels. In response to a brake pressure at the pneumatic control port, the pneumatically switchable valve preferably switches into the venting position and thus vents the first select input. As a result, no pressure is present at the select output.It is preferred that the first electromagnetic switching valve is connected to the first service brake pressure connection or a brake pressure connection of a front axle brake pressure modulator or a brake pressure connection of a redundancy brake pressure modulator, wherein the first electromagnetic switching valve is configured to pass a brake pressure to the relay valve control connection without current. It is particularly preferred in this respect that the first electromagnetic switching valve is designed as a 3 / 2-way valve. A first inlet of the first electromagnetic switching valve is, as already described above, preferably connected to the first compressed air supply. A second input of the first electromagnetic switching valve is preferably connected to the service brake pressure connection or a brake pressure connection of a front axle brake pressure modulator or a brake pressure connection of a redundancy brake pressure modulator. In particular, it is preferred that the first output of the first electromagnetic switching valve is connected to the second select input. The brake pressure preferably does not pass directly to the relay valve control connection, but rather it is preferred that the select-low valve is arranged between the first output of the first electromagnetic switching valve and the relay valve control connection.Preferably, the electro-pneumatic valve arrangement comprises a double venting check valve. A first double ventilation check valve inlet is preferably connected to the first electromagnetic switching valve, in particular to the first outlet of the first electromagnetic switching valve. A second double venting check valve inlet is preferably connected to the relay valve working connection. A venting double check valve outlet is preferably connected to the second control connection of the reversing relay valve. It should be understood that the double ventilation check valve is designed to always discharge the greater of the pressures present at the two double ventilation check valve inputs via the double ventilation check valve output. The double ventilation check valve is preferably configured to connect that double ventilation check valve inlet to the double ventilation check valve outlet at which the higher pressure is present. In particular, it is preferred that the first electromagnetic switching valve, preferably the second input of the first electromagnetic switching valve, is connected to a brake pressure connection of a front axle brake pressure modulator. If the first service brake circuit or the service brake pressure modulator or the electronic service brake control unit fails or has a fault, the brake pressure from the front axle brake pressure modulator can be provided as a second control pressure at the second control connection of the reversing relay valve via the first electromagnetic switching valve and the ventilation double check valve, in order thus to additionally brake the vehicle by venting the spring brake cylinder.Preferably, the reversing relay valve has at least one open position and one closed position. In the open position, the reversing relay valve is preferably configured to open a ventilation path between the first supply connection and the working connection for ventilating the spring brake cylinder. In the closed position in the reversing relay valve, it is preferably configured to open a venting path between the working connection and the venting for venting the spring brake cylinder. Preferably, the reversing relay valve comprises a reversing relay valve piston which is configured to be moved between the open position and the closed position. Depending on the pressure equilibrium, intermediate positions are also provided.Preferably, the first supply connection of the reversing relay valve is connected to the first compressed air supply for supplying the reversing relay valve with compressed air. In a preferred development, the reversing relay valve has a second supply connection which is connected to a second compressed air supply. The provision of two supply connections on the reversing relay valve, which are each supplied by a compressed air supply, can further increase the reliability of the brake system, which remains airable even in the event of failure of one of the compressed air supplies of the spring-loaded brake cylinders.The electronically controllable pneumatic brake system preferably has a first voltage source and a second voltage source, wherein the first voltage source is provided for supplying the electronic service brake control unit with electrical voltage, and wherein the second voltage source is provided for supplying the electronic control unit with electrical voltage. Preferably, the first voltage source supplies, alternatively or additionally, the parking brake module with electrical voltage. The provision of mutually independent voltage sources can further increase the reliability of the brake system, since a failure of an individual voltage source does not cause a total failure of the parking brake device.The electronically controllable pneumatic brake system preferably has a redundancy brake pressure modulator and an electronic redundancy brake control unit. The redundant brake pressure modulator is preferably connected to the redundant brake electronic control unit and preferably receives secondary switching signals from the redundant brake electronic control unit for switching at least one electromagnetic valve of the redundant brake pressure modulator. The electropneumatic valve arrangement is preferably actuated by the electronic redundancy brake control unit. The redundant brake pressure modulator and the electronic redundant operating brake control unit are preferably units of a secondary system of the electronically controllable pneumatic brake system. The secondary system is preferably designed to control a service brake pressure for the at least first service brake actuator of the vehicle if a fault is determined in the primary system. The secondary system then preferably forms a redundancy level for the primary system, which is provided in particular in vehicles with a high degree of automation.In a second aspect of the invention, the object mentioned at the beginning is achieved by a method for controlling a vehicle, in particular a commercial vehicle, having an electronically controllable pneumatic brake system, preferably according to one of the above-described preferred embodiments of an electronically controllable pneumatic brake system according to the first aspect of the invention. The method comprises supplying a first supply connection of a reversing relay valve of a parking brake device with compressed air, wherein the reversing relay valve is configured to vent and vent at least one first spring brake cylinder of the vehicle. The method comprises venting a first control connection of the reversing relay valve with a parking brake pressure of a parking brake module of the parking brake device, so that the spring-loaded brake cylinder is ventilated. It should thus be understood that the vehicle is in a driving state and the parking brakes are released. In an operating case, for braking the vehicle, a service brake pressure for at least one first service brake actuator of the vehicle is preferably controlled by a first service brake pressure modulator. In a fault case, in which a fault has been determined in the parking brake device and / or the parking brake module, which at least partially prevents the parking brake pressure from being controlled, an electropneumatic valve arrangement having an electronic control unit, which is independent of the parking brake module, is actuated for venting a second control connection of the reversing relay valve with a second control pressure, so that the spring-loaded brake cylinder is vented. The method preferably alternatively or additionally comprises, in a fault case in which a fault in the service brake pressure modulator and / or in an electronic service brake control unit which is connected to the service brake modulator and provides primary switching signals at the latter for switching at least one electromagnetic valve of the first service brake pressure modulator, has been determined, wherein the fault is a fault which at least partially prevents braking in an operating level of the vehicle, the electropneumatic valve arrangement having the electronic control unit, which is independent of the parking brake module, being actuated for venting the second control connection of the reversing relay valve with one or the second control pressure, such that the spring accumulator brake cylinder is vented. It should be understood that by metered venting of the spring brake cylinder, the vehicle can be braked and stopped reliably. If a parking brake module of the parking brake device is still functional, wherein the parking brake module is configured to provide a parking brake pressure at a parking brake pressure connection which is connected to the first control connection of the reversing relay valve, the spring-loaded brake cylinder can also be ventilated by venting the first control connection of the reversing relay valve and the vehicle can thus be braked and stopped reliably.For an anti-compound function, the method preferably comprises supplying the first supply connection of the reversing relay valve with compressed air, activating the electropneumatic valve arrangement with the electronic control unit, which is independent of the parking brake module, for venting the second control connection of the reversing relay valve with a second control pressure, and venting a third control connection of the reversing relay valve, which is connected to a first service brake pressure connection of the service brake pressure modulator, with a service brake pressure from the service brake pressure modulator, so that the spring brake cylinder is vented as a result. It should be understood that the anti-compound function is activated, for example, in a state in which the vehicle is stopped and in which the parking brakes of the vehicle are set. By venting the spring brake cylinder, the associated parking brake can be released.According to a third aspect of the invention, the object mentioned at the beginning is achieved by a vehicle, in particular a commercial vehicle, having a front axle, at least one first rear axle and an electronically controllable pneumatic brake system according to one of the above-described preferred embodiments of an electronically controllable pneumatic brake system according to the first aspect of the invention.It should be understood that the electronically controllable pneumatic brake system according to the first aspect of the invention and the utility vehicle according to the third aspect of the invention can have the same and similar sub-aspects as laid down in particular in the dependent claims. Preferably, the first service brake circuit is a rear axle service brake circuit. The first service brake pressure modulator is preferably a rear axle operating brake pressure modulator which has at least one first service brake pressure connection for controlling a service brake pressure for at least one first service brake actuator at a rear axle of the vehicle.In a fourth aspect of the invention, the object mentioned at the beginning is achieved by using a reversing relay valve for supplying and venting at least one first spring-loaded brake cylinder of a vehicle. The reversing relay valve has a first control connection, a second control connection, a working connection, at least one first supply connection and a vent. The first control port is connected to a parking brake pressure port of a parking brake module for receiving a parking brake pressure. The second control port is connected to an electro-pneumatic valve arrangement for receiving a second control pressure, wherein the electro-pneumatic valve arrangement is actuated by an electronic control unit which is independent of the parking brake module.Embodiments of the invention will now be described below with reference to the drawings. These are not necessarily intended to represent the embodiments to scale, but rather the drawings are embodied in schematic and / or slightly distorted form, if this is useful for explanation. With regard to additions to the teachings that can be directly recognized from the drawings, reference is made to the relevant prior art. It should be understood that various modifications and changes may be made to the form and detail of an embodiment without departing from the general spirit of the invention. The features of the invention disclosed in the description, in the drawings and in the claims can be essential for the development of the invention both individually and in any combination. Moreover, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or detail of the preferred embodiments shown and described below, or limited to an object that would be limited compared to the object claimed in the claims. In the case of specified rated ranges, values lying within the stated limits should also be disclosed as limit values and can be used and claimed as desired. For the sake of simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar function.Further advantages, features and details of the invention are apparent from the following description of the preferred embodiments and from the drawings, in which: FIG. 1 shows a schematic illustration of a first exemplary embodiment of the electronically controllable pneumatic brake system; FIG. 2 shows a schematic illustration of a second exemplary embodiment of the electronically controllable pneumatic brake system; FIG. 3 shows a schematic illustration of a third exemplary embodiment of the electronically controllable pneumatic brake system; and FIGS. 4A-4E show switching positions of a reversing relay valve.FIG. 1 shows an electronically controllable pneumatic brake system 100 having a parking brake device 1. the electronically controllable pneumatic brake system 100 is used in the present case in a vehicle 300 designed as a commercial vehicle 302, which is shown here in a highly schematic manner. In particular, a first axle 101 of the vehicle 300 is schematically illustrated. The first axle 101 is preferably a first rear axle 102 of the vehicle 300.The electronically controllable pneumatic brake system 100 here has a first service brake actuator 106 and a second service brake actuator 107 for one wheel of the vehicle 300 in each case. A first service brake circuit 103, in particular a first rear axle operating brake circuit 104, is provided for supplying the first and the second service brake actuators 106, 107. The first and second service brake actuators 106, 107 may also be referred to as first and second rear axle operational brake actuators 106, 107. The first service brake circuit 103 is supplied with supply pressure pV from a first compressed air supply 108.In addition to the service brake actuators 106, 107, the brake system 100 has a first spring-loaded brake cylinder 110 and a second spring-loaded brake cylinder 112. In particular, the service brake actuators 106, 107 each comprise a spring brake cylinder 110, 112 and are designed as double-acting brake actuators, which are also referred to as tri-stop cylinders. The spring-loaded brake cylinders 110, 112 are designed to apply the brakes of the vehicle 300 when they are depressurized or depressurized. The spring-loaded brake cylinders 110, 112 can thus advantageously be used as a parking brake, which does not have to be supplied with compressed air for braking the first axle 101. To release the wheels, the spring-loaded brake cylinders 110, 112 must be ventilated.The first service brake circuit 103 has a first service brake pressure modulator 105. The service brake pressure modulator 105 has a first service brake pressure connection p 21 for controlling a service brake pressure pB for the first service brake actuator 106 of the vehicle 300. The service brake pressure modulator 105 has a second service brake pressure connection p 22 for controlling a service brake pressure pB for the second service brake actuator 107 of the vehicle 300. In other embodiments, however, the first service brake pressure connection p 21 and the second service brake pressure connection p 22 can also be combined and the first service brake pressure modulator 105 can thus be designed as a single-channel axle modulator. For receiving a supply pressure pV, the service brake pressure modulator 105 has a compressed air supply connection p 1, via which the service brake pressure modulator 105 is connected to the first compressed air supply 108.The brake system 100 comprises an electronic service brake control unit ECU 1 connected to the service brake pressure modulator 105. The electronic service brake control unit ECU 1 is configured to provide primary switching signals PS to the service brake pressure modulator 105 for switching at least one electromagnetic valve (not shown) of the first service brake pressure modulator 105. The service brake electronic control unit ECU 1 preferably receives brake request signals of a driver or a virtual driver (not shown), based on which the service brake electronic control unit ECU 1 outputs the primary switching signals PS to the service brake pressure modulator 105. Preferably, the service brake electronic control unit ECU 1 is connected via a vehicle bus to an autonomous driving unit (virtual driver) and receives maneuver-related data (not shown) therefrom.The parking brake device 1 has a parking brake module 2 and a reversing relay valve 4. The parking brake module 2 has a parking brake pressure port p 52, at which it can provide a parking brake pressure pF. The parking brake module 2 preferably responds to a parking request or a driving-off request of a driver or a virtual driver (not shown). In response to a start request or during driving, the parking brake module 2 is preferably configured to provide the parking brake pressure pF. If the driver wishes to park, compressed air is no longer provided at the parking brake pressure connection p 52, and as a result the reversing relay valve 4 vents the spring-loaded brake cylinders 110, 112.The reversing relay valve 4 has a first control port p 43 connected to the parking brake pressure port p 52. The parking brake pressure port p 52 is connected to the first control port p 43 via a parking brake pressure air line 113. The first control port p 43 is configured to receive the parking brake pressure pF provided at the parking brake pressure port p 52. The reversing relay valve 4 further has a second control terminal p42. The reversing relay valve 4 is connected via the second control connection p 42 to an electropneumatic valve arrangement 6. In addition, the reversing relay valve 4 according to FIG. 1 has a third control connection p 41. The third control port p 41 is connected to the first service brake pressure port p 21, in particular via a first service brake pressure air line 120. The third control port p 41 is configured to receive a service brake pressure pB from the service brake pressure modulator 105. It should be understood that the third control port p 41 can also be connected to the second service brake pressure port p 22, or, if the service brake pressure modulator 105 is designed as a single-channel axle modulator, to a combined service brake pressure port.The reversing relay valve 4 also has a first supply connection p 11, a second supply connection p 12, a working connection p 2 and a vent p 3. The first supply connection p 11 is connected to the first compressed air supply 108. The second supply connection p 12 is connected to a second compressed air supply 109. The reversing relay valve 4 is thus supplied with compressed air both from the first compressed air supply 108 and from the second compressed air supply 109. Even in the event of failure of one of the compressed air supplies 108, 109, the reversing relay valve 4 is accordingly still supplied with compressed air.The working connection p 2 is connected to the first and the second spring-loaded brake cylinders 110, 112. For venting the first and second spring-loaded brake cylinders 110, 112, the reversing relay valve 4 provides a working pressure pA at the working connection p 2. By providing the working pressure pA, the reversing relay valve 4 vents the spring-loaded brake cylinders 110, 112 and thus releases the parking brake of the vehicle 300. To engage the parking brake of vehicle 300, reversing relay valve 4 may vent spring-loaded brake cylinders 110, 112. For this purpose, the reversing relay valve 4 can connect the spring-loaded brake cylinders 110, 112 to the vent p 3 in a fluid-conducting manner.The electropneumatic valve arrangement 6 has a relay valve 8 according to FIG. 1. The relay valve 8 has a relay valve supply connection 8.1, a relay valve working connection 8.2, a relay valve control connection 8.3 and a relay valve venting connection, not shown here. The relay valve supply connection 8.1 is connected via a double supply check valve 10 to the first compressed air supply 108 and the second compressed air supply 109. It should be understood that the dual reservoir check valve 10 is optional. The dual supply check valve 10 has a first dual supply check valve inlet 10.1, which is connected to the first compressed air supply 108, a second dual supply check valve inlet 10.2, which is connected to the second compressed air supply 109, and a dual supply check valve outlet 10.3, which is connected to the relay valve supply connection 8.1. The dual supply check valve 10 is designed in such a way that the greater of the pressures present at the two dual supply check valve inputs 10.1, 10.2 is always output via the dual supply check valve output 10.3. Thus, if a fault occurs in one of the two compressed air supplies 108, 109, the relay valve 8 can continue to be supplied with compressed air. If no double supply check valve 10 is provided, the relay valve supply connection 8.1 is preferably connected to the first compressed air supply 108. It should be understood that if no double supply check valve 10 is provided, the relay valve supply connection 8.1 can also be connected to the second compressed air supply 109. The relay valve working connection 8.2 of the relay valve 8 is connected to the second control connection p42, in particular via a control pressure air line 130. A second control pressure pS2 can be controlled by the relay valve 8 at the second control connection p42 via the control pressure air line 130.According to FIG. 1, the electropneumatic valve arrangement 6 furthermore has a first electromagnetic switching valve SV-A. The first electromagnetic switching valve SV-A is designed as a 2 / 2-way valve according to FIG. 1 and has an open position and a closed position. The first electromagnetic switching valve SV-A is de-energized in the closed position and energized in the open position. In the open position, the electromagnetic switching valve SV-A connects the first compressed air supply 108 to the relay valve control connection 8.3. The first electromagnetic switching valve SV-A is electronically controlled by an electronic control unit ECU 2. The electronic control unit ECU 2 is a control unit independent of the parking brake module 2. The electronic control unit ECU 2 is a control unit independent of the service brake electronic control unit ECU 1.If a fault has been determined in the parking brake module 2, in particular if the parking brake module 2 actuates a parking brake pressure pF, although parking of the vehicle 300 by the driver or virtual driver is desired, the electronic control unit ECU 2 actuates an electronic switching signal to the first electromagnetic switching valve SV-A, such that the first electromagnetic switching valve SV-A switches from the closed position into the open position. In the open position of the first electromagnetic switching valve SV-A, compressed air reaches the relay valve control connection 8.3 from the first compressed air supply 108. When the relay valve 8 is actuated by the first electromagnetic switching valve SV-A, it switches into an open position and opens a flow path between the relay valve supply connection 8.1 and the relay valve working connection 8.2. The compressed air then reaches the second control connection p 42 as a second control pressure pS 2 via the control pressure air line 130 from the relay valve 8. The reversing relay valve 4 is configured to vent the first and the second spring brake cylinders 110, 112 for a case in which the first and the second control connections p 43, p 42 are vented, the third control connection p 41 is vented and a supply pressure is applied to the first supply connection p 11. Thus, in this case, the parking brake of the vehicle 300 can be engaged and the vehicle can be safely parked even if a fault is present in the parking brake module 2.In addition, in the event of a fault in the first service brake circuit 103, for example a fault in the first service brake pressure modulator 105, which has the result that the vehicle 300 can no longer be braked via the first axle 101 and no service brake pressure pB is present at the third control connection p 41, the vehicle 300 can be braked as an auxiliary means by controlling the second control pressure pS 2 at the second control connection p 42 of the reversing relay valve 4.The electro-pneumatic valve arrangement 6 further comprises a second electromagnetic switching valve SV-B. The second electromagnetic switching valve SV-B is designed as a 3 / 2-way valve. The second electromagnetic switching valve SV-B has a passing position and a venting position. The second electromagnetic switching valve SV-B is de-energized in the open position and energized in the vent position. In the open position, the second electromagnetic switching valve SV-B connects the relay valve working connection 8.2 to the relay valve control connection 8.3. Consequently, the second electromagnetic switching valve SV-B enables compressed air to be fed back from the relay valve working connection 8.2 to the relay valve control connection 8.3, so that the relay valve 8 remains activated until the second electromagnetic switching valve SV-B switches from the open position into the closed position. The second electromagnetic switching valve SV-B is also controlled by the electronic control unit ECU 2.Thus, if the second control connection p 42 of the reversing relay valve 4 is to be ventilated, it is sufficient to actuate the first electromagnetic switching valve SV-A for a short time, so that the relay valve 8 is actuated. The relay valve 8 then remains activated on the basis of the "loop" or the return. If ventilation of the second control port p 42 is no longer desired, the second electromagnetic switching valve SV-B can be controlled by the electronic control unit ECU 2, so that it switches into the venting position and the return is interrupted.For detecting a pressure in the control pressure air line 130, the brake system 100 has a first pressure sensor 40. The first pressure sensor 40 is connected to the electronic control unit ECU 2 and provides signals corresponding to the respectively detected pressure to the electronic control unit ECU 2. The electronic control unit ECU 2 is designed to determine which pressure or whether a pressure is present in the control pressure air line 130 using the signals of the first pressure sensor 40. In the embodiment shown, the electronic control unit ECU 2 can thus determine whether a second control pressure pS 2 is present at the second control connection p 42 of the reversing relay valve 4. This makes it possible to check whether the electropneumatic valve arrangement 6 is functional or has a fault.The electronic service brake control unit ECU 1 is supplied with electrical voltage from a first voltage source 115. The first voltage source 115 is furthermore also connected to the parking brake module 2 and is configured to supply the parking brake module with electrical voltage. The electronic control unit ECU 2, on the other hand, is supplied with electrical voltage by a second voltage source 114. The separate power supply of the electronic service brake control unit ECU 1 and the electronic control unit ECU 2 prevents a failure of one of the voltage sources 114, 115 from resulting in a total failure of the parking brake device 1. The electronic control unit ECU 2 is independent of the first voltage source 115. The electronic control unit ECU 2 is independent of the electronic service brake control unit ECU 1.The exemplary embodiment of FIG. 2 differs from the exemplary embodiment of FIG. 1 in particular in the electropneumatic valve arrangement 6. the electropneumatic valve arrangement 6 has here, in addition to the first electromagnetic switching valve SV-A, which is designed here as a 3 / 2-way valve, the second electromagnetic switching valve SV-B, the relay valve 8 and the reservoir double check valve 10, a select-low valve SLV, a pneumatically switchable valve INV and a venting double check valve 14.The pneumatically switchable valve INV is designed as a 3 / 2-way valve according to FIG. 2 and has a passage position and a venting position. The pneumatically switchable valve INV is pressureless in the passage position and pressurized in the venting position. The pneumatically switchable valve INV has a first outlet INV.1, a first inlet INV.2, a venting outlet INV.3 and a pneumatic control connection INV.4. The select-low valve SLV has a first select input SLV.1, a second select input SLV.2 and a select output SLV.3. The first select input SLV.1 is connected to the pneumatically switchable valve INV, in particular to the first output INV.1 of the pneumatically switchable valve INV. The pneumatically switchable valve INV is configured to vent the first select input SLV.1 in response to a pneumatic control pressure pnS at the pneumatic control connection INV.4, i.e. when the pneumatically switchable valve INV is pressurized. For this purpose, the pneumatically switchable valve INV switches into the venting position, i.e. into a position in which the first outlet INV.1 is connected to the venting outlet INV.3.The select-low valve SLV is configured to output the lower of the pressures present at the two select inputs SLV.1, SLV.2 via the select output SLV.3. If the first select input SLV.1 is now vented, no pressure is applied via the select output SLV.3. The select output SLV.3 is connected to the relay valve control connection 8.3 with the interposition of a nonreturn valve 50. If, therefore, no pressure is output via the select output SLV.3, the relay valve 8 cannot be activated initially. Only when both the first select inlet SLV.1 and the second select inlet SLV.2 are aerated can the relay valve 8 be activated initially. The relay valve 8 then remains activated until the second electromagnetic switching valve SV-B is activated and the return from the relay valve working connection 8.2 to the relay valve control connection 8.3 is thus interrupted. The check valve 50 is configured to block the compressed air in the "loop", so that the compressed air cannot escape via the select-low valve SLV and the vent output INV.3.According to FIG. 2, the pneumatic control port INV.4 of the pneumatically switchable valve INV is connected to a brake pressure port p200 of a front axle brake pressure modulator 150. It should be understood that the pneumatic control port INV.4 can also be connected to the first service brake pressure port p 21, the second service brake pressure port p 22, or a brake pressure port of a redundancy brake pressure modulator. The pneumatic control port INV.4 is configured to receive a brake pressure from the front axle brake pressure modulator 150 as a pneumatic control pressure pnS. If the service brakes are therefore actuated, the pneumatically switchable valve INV is actuated with a brake pressure by the front axle brake pressure modulator 150. In response to a brake pressure at the pneumatic control port INV.4, the pneumatically switchable valve INV switches into the venting position and thus vents the first select input SLV.1. Since the pneumatic control port INV.4 of the pneumatically switchable valve INV is connected to the brake pressure port p200 of the front axle brake pressure modulator 150, the pneumatically switchable valve INV can also be activated when the first service brake pressure modulator 105 has a fault.As already described above, the first electromagnetic switching valve SV-A according to FIG. 2 is designed as a 3 / 2-way valve. The electromagnetic switching valve SV-A has a first input SV-A.1, a second input SV-A.2, a first output SV-A.3 and an electronic control connection SV-A.4. The first inlet SV-A.1 of the first electromagnetic switching valve SV-A is connected to the first compressed air supply 108. The second input SV-A.2 of the first electromagnetic switching valve SV-A is connected to the brake pressure connection p200 of the front axle brake pressure modulator 150. It should be understood that the second inlet SV-A.2 of the first electromagnetic switching valve SV-A can also be connected to the first service brake pressure connection p21, the second service brake pressure connection p22 or a brake pressure connection of a redundancy brake pressure modulator. The first output SV-A.3 of the first electromagnetic switching valve SV-A is connected to the second select input SLV.2. The electronic control port SV-A.4 of the first electromagnetic switching valve SV-A is connected to the electronic control unit ECU2. The first electromagnetic switching valve SV-A is de-energized in a position in which the second input SV-A.2 is connected to the first output SV-A.3. The first electromagnetic switching valve SV-A is energized in a position in which the first input SV-A.1 is connected to the first output SV-A.3.If the service brakes are therefore actuated, the pneumatically switchable valve INV is actuated with a brake pressure from the front axle brake pressure modulator. The pneumatically switchable valve INV switches into the venting position and vents the first select input SLV.1. In addition, the brake pressure controlled by the front axle brake pressure modulator 150 is controlled through from the second input SV-A.2 of the first electromagnetic switching valve SV-A to the first output SV-A.3 of the first electromagnetic switching valve SV-A and reaches the second select input SLV.2. Thus, the first select input SLV.1 is vented and the second select input SLV.2 is vented, thereby venting the first select output SLV.3. As a result, the relay valve 8 cannot be initially actuated and no pressure is output from the relay valve 8 via the relay valve working connection 8.2.In order that a second control pressure pS2can nevertheless be provided at the second control connection p42of the reversing relay valve 4, the electropneumatic valve arrangement 6 has the venting double check valve 14. A first venting double check valve inlet 14.1 of the venting double check valve 14 is connected to the first electromagnetic switching valve SV-A, in particular to the first outlet SV-A.3 of the first electromagnetic switching valve SV-A. A second aeration double check valve inlet 14.2 of the aeration double check valve 14 is connected to the relay valve working connection 8.2. A venting double check valve outlet 14.3 of the venting double check valve 14 is connected to the second control connection p42 of the reversing relay valve 4. The double ventilation check valve 14 is designed to discharge the greater of the pressures present at the two double ventilation check valve inlets 14.1, 14.2 via the double ventilation check valve outlet 14.3.If the service brakes are actuated, the brake pressure controlled by the front axle brake pressure modulator 150 is controlled through from the second inlet SV-A.2 of the first electromagnetic switching valve SV-A to the first outlet SV-A.3 of the first electromagnetic switching valve SV-A and, in addition to the second select inlet SLV.2, is provided at the first venting double check valve inlet 14.1. Since a greater pressure is then present at the first venting double check valve inlet 14.1 than at the second venting double check valve inlet 14.2 (here, no pressure is present when the service brakes are actuated due to the pneumatically switchable valve INV), the venting double check valve 14 connects the first venting double check valve inlet 14.1 to the venting double check valve outlet 14.2. As a result, a second control pressure pS2 is provided at the second control port p42 of the reversing relay valve 4.The fact that a second control pressure pS2is present at the second control port p42of the reversing relay valve 4 is particularly expedient for this reason in order to additionally brake the vehicle 300 by venting the first and second spring brake cylinders in the event of a fault in which the first service brake circuit 103 or the first service brake pressure modulator 105 or the electronic service brake control unit ECU1 fails or has a fault, but the front axle brake pressure modulator 150 is still functional and can actuate at least one first front axle operating brake actuator (not shown).In the event of a fault in which both the first service brake pressure modulator 105 and / or the electronic service brake control unit ECU 1 fails or has a fault and the front axle brake pressure modulator 150 fails or has a fault, the first electromagnetic switching valve SV-A can be switched by the electronic control unit ECU 2 electronically actuating the first electromagnetic switching valve SV-A into the position in which the first input SV-A.1 of the first electromagnetic switching valve SV-A is connected to the first output SV-A.3 of the first electromagnetic switching valve SV-A. As a result, compressed air is passed from the first compressed air supply 108 to the second select inlet SLV.2 and the first venting double check valve inlet 14.1. In this case, compressed air is also present at the second venting double check valve inlet 14.2. Since the pneumatically switchable valve INV remains non-energized when the front axle brake pressure modulator 150 fails, it passes compressed air from the first compressed air supply 108 to the first select input SLV.1. Compressed air is then present at the select-low valve SLV both at the first select inlet SLV.1 and at the second select inlet SLV.2, as a result of which the first select outlet SLV.3 is also aerated. The relay valve 8 is controlled and switches into an open position and opens a flow path between the relay valve supply connection 8.1 and the relay valve working connection 8.2. The compressed air then reaches the second aeration double check valve inlet 14.2 from the relay valve working connection 8.2. The compressed air then reaches the second control connection p 42 of the reversing relay valve 4 from the venting double check valve outlet 14.3 as a second control pressure pS 2, as a result of which the vehicle 300 can be braked by venting the first and the second spring-loaded brake cylinder 110, 112.The exemplary embodiment of FIG. 3 differs from the exemplary embodiment of FIG. 2 in that the electropneumatic valve arrangement 6 does not have a double reservoir check valve 10. It should be understood that the exemplary embodiment of FIG. 1 can also be designed without a double reservoir check valve 10. By omitting the double reservoir check valve 10, space can be saved and the interconnection effort can be reduced.FIG. 4A shows a first switching state of the reversing relay valve 4 in an operating case when the parking brakes of the vehicle are fixed, i.e. the first and the second spring-loaded brake cylinders 110, 112 are vented. It should be understood that the construction of such reversing relay valves 4 is known from the prior art. The following explanations concerning the switching states of the reversing relay valve 4 are intended in particular to provide an understanding of the invention. The reversing relay valve 4 has the first control port p 43, the second control port p 42, the third control port p 41, the working port p 2, the first reservoir port p 11, and the vent p 3. It should be understood that the reversing relay valve 4 shown can also have the second supply connection p 12. For the interconnection of the connections, reference is made to the above description of the figures.The reversing relay valve 4 has an open position and a closed position. In the open position, the reversing relay valve 4 is configured to open a ventilation path 20 between the first supply connection p 11 and the working connection p 2 for ventilating the first and the second spring-loaded brake cylinder 110, 112. In the closed position in the reversing relay valve 4, it is preferably configured to open a venting path 30 between the working connection p 2 and the venting p 3 for venting the first and the second spring-loaded brake cylinder 110, 112. The reversing relay valve 4 has a reversing relay valve piston 35 which is configured to be moved between the open position and the closed position.According to FIG. 4A, the reversing relay valve 4 is in the closed position; consequently, the venting path 30 between the working connection p 2 and the venting p 3 is released and the first and the second spring-loaded brake cylinders 110, 112 are vented. In the operating case shown, neither the first, the second nor the third control connection p 43, p 42, p 41 are aerated. The vehicle 300 is thus in a parked state, the service brakes are not applied.FIG. 4B shows a second switching state of the reversing relay valve 4 in an operation case when the parking brakes of the vehicle 300 are released. For this purpose, the parking brake module 2 provides a parking brake pressure pF at the first control port p 43. The first control connection p 43 of the reversing relay valve 4 is thus vented. The parking brake pressure pF reaches from the first control connection p 43 into a first compressed air chamber 45 of the reversing relay valve 4. the pressure in the first compressed air chamber 45 causes the reversing relay valve piston 35 to be moved from the closed position into the open position, wherein FIG. 4B shows the open position. To move the reversing relay valve piston 35 from the closed position to the open position, the reversing relay valve piston 35 is pressed vertically downward by the pressure in the first compressed air chamber 45. The second control connection p 42 and the third control connection p 43 are vented in this switching state.In the open position, the reversing relay valve 4 opens a venting path 20 between the first supply connection p 11 and the working connection p 2, and the first and the second spring-loaded brake cylinders 110, 112 are vented. It should be understood that FIG. 4B shows a switching state in which the reversing relay valve 4 is not yet in a balanced position and the parking brakes are not yet fully released.In FIG. 4C, a third switching state of the reversing relay valve 4 is then shown in an operating case in which the reversing relay valve 4 is in a balanced position. The reversing relay valve 4 is in the open position and opens the venting path 20 between the first supply connection p 11 and the working connection p 2, so that the first and the second spring-loaded brake cylinders 110, 112 remain vented. The parking brakes are fully released and the vehicle 300 is in a driving state.FIG. 4D shows a fourth switching state of the reversing relay valve 4 in an operating case for an anti-compound function. The anti-compound function serves to avoid a mechanical overload of the brake pistons by adding brake forces from the service brakes and the spring-loaded brakes. It should be understood that the anti-compound function is used when the service brakes are actuated while the parking brakes are active. The first supply connection p 11 is supplied with compressed air. The first control port p 43 is vented. The second and third control ports p42, p41 are vented. The ventilation of the second and the third control connections p 42, p 41 results from the actuation of the service brakes (cf. the embodiment in this regard with respect to FIG. 2 ) or by actuation of the electropneumatic valve arrangement 6, in particular by actuation of the first electromagnetic switching valve SV-A (cf. the embodiment in this regard with respect to FIG. 1 ). The service brake pressure pB, which is present at the third control port p 41, reaches from the third control port p 41 into the first compressed air chamber 45 of the reversing relay valve 4. the pressure in the first compressed air chamber 45 causes the reversing relay valve piston 35 to be moved from the closed position into the open position, wherein FIG. 4D shows the open position.To move the reversing relay valve piston 35 from the closed position to the open position, the reversing relay valve piston 35 is pressed vertically downward by the pressure in the first compressed air chamber 45. In the open position, the first supply connection p 11 and the working connection p 2 are now connected to one another, so that the first and the second spring-loaded brake cylinders 110, 112 are ventilated while the service brakes are actuated. It should be understood that the application of a second control pressure pS2 to the second control connection p42 has no effect on the anti-compound function of the reversing relay valve 4. In addition, it should be understood that no application of a second control pressure pS2 to the second control connection p42 is necessary for the anti-compound function. For the anti-compound function, it is sufficient if the third control port p 41 is ventilated, as would be the case, for example, according to the exemplary embodiment of FIG. 1, if the service brakes are actuated with fixed parking brakes.FIG. 4E shows a fifth switching state of the reversing relay valve 4 in a first fault case. The fault event comprises a fault in the parking brake module 2 and / or in the first service brake circuit 103, in particular in the first service brake pressure modulator 105, and / or in the electronic service brake control unit ECU 1. In the event of failure of the parking brake module 2, the parking brake module 2 controls a parking brake pressure pF at the first control port p 43 even though the vehicle 300 is to be parked. In order that the vehicle 300 can nevertheless be parked safely, the second control port p 42 is ventilated in this case. When the reversing relay valve 4 is used in an electronically controllable pneumatic brake system 100 as shown in FIG. 1, the electro-pneumatic valve arrangement 6, in particular the first electromagnetic switching valve SV-A, is actuated by the electronic control unit ECU 2 in order to vent the second control connection p 42. Energized, the first electromagnetic switching valve SV-A switches into the open position, so that compressed air reaches the relay valve control connection 8.3 from the first compressed air supply 108. The relay valve 8 is thus controlled and subsequently controls the second control pressure pS2 at the second control connection p42 of the reversing relay valve 4. If the reversing relay valve 4 is used in an electronically controllable pneumatic brake system 100 as shown in FIG. 2 or 3, the first electromagnetic switching valve SV-A can likewise be switched by the electronic control unit ECU 2 into the position in which the first input SV-A.1 of the first electromagnetic switching valve SV-A is connected to the first output SV-A.3 of the first electromagnetic switching valve SV-A by electronically activating the first electromagnetic switching valve SV-A. As a result, compressed air is passed from the first compressed air supply 108 to the second select inlet SLV.2 and the first venting double check valve inlet 14.1. In this case, compressed air is also present at the second venting double check valve inlet 14.2. The pneumatically switchable valve INV namely controls the compressed air coming from the first compressed air supply 108 to the first select input SLV.1. Pressure is thus present both at the first select input SLV.1 and at the second select input SLV.2, so that pressure is also present at the select output SLV.3 and at the relay valve control connection 8.3. The relay valve 8 switches into the open position and controls pressure at the relay valve working connection 8.2 to the second venting double check valve inlet 14.2. From the venting double check valve outlet 14.3, the compressed air then reaches the second control connection p42 of the reversing relay valve 4 as a second control pressure pS2.The second control pressure pS2 which is present at the second control port p42 reaches from the second control port p42 into a second compressed air chamber 55 of the reversing relay valve. The pressure in the second pressurized air chamber 55 causes the reversing relay valve piston 35 to be moved from the open position to the closed position, with FIG. 4E showing the closed position. To move the reversing relay valve piston 35 from the open position to the closed position, the reversing relay valve piston 35 is pushed upward in the vertical direction by the pressure in the second compressed air chamber 55. In the closed position, the venting path 30 between the working connection p 2 and the venting p 3 is released, so that the first and the second spring-loaded brake cylinders 110, 112 can be discharged in a metered manner and the vehicle 300 can be braked and parked safely.Reference Sign (Part of Description)1 Parking brake device 2 Parking brake module 4 Reversing relay valve 6 Electropneumatic valve arrangement 8 Relay valve 8.1 Relay valve supply connection 8.2 Relay valve working connection 8.3 Relay valve control connection 10 Dual supply check valve 10.1 First dual supply check valve inlet 10.2 Second dual supply check valve inlet 10.3 Dual supply check valve outlet 14 Dual ventilation check valve 14.1 First dual ventilation check valve inlet 14.2 Second dual ventilation check valve inlet 14.3 Dual ventilation check valve outlet 20 Ventilation path 30 Ventilation path 35 Reversing relay valve piston 40 Pressure sensor 45 First compressed air chamber 50 Check valve 55 Second compressed air chamber 100 Electronically controllable pneumatic brake system 101 First axle 102 First rear axle 103 First service brake circuit 104 First rear axle operating brake circuit 105 First service brake pressure modulator 106 First service brake actuator 107 Second service brake actuator 108 First compressed air supply 109 Second compressed air supply 110 First compressed air chamber 100 Spring-loaded brake cylinder 112 Second spring-loaded brake cylinder 113 Parking brake pressure air line 114 Second voltage source 115 First voltage source 120 Service brake pressure air line 130 Control pressure air line 150 Front axle brake pressure modulator 300 Vehicle 302 Commercial vehicle ECU 1 Electronic service brake control unit ECU 2 Electronic control unit INV Pneumatically switchable valve INV.1 First output of the pneumatically switchable valve INV.2 First input of the pneumatically switchable valve INV.3 Venting output of the pneumatically switchable valve INV.4 Pneumatic control connection SLV Select-Low valve SLV.1 First select input SLV.2 Second select input SLV.3 Select output SV-A First electromagnetic switching valve SV-A.1 First input of the first electromagnetic switching valve sv-a.2 second input of the first electromagnetic switching valve SV-A.3 first output of the first electromagnetic switching valve SV-A.4 electronic control connection of the first electromagnetic switching valve SV-B second electromagnetic switching valve pA working pressure pB service brake pressure pF parking brake pressure pnS pneumatic control pressure PS primary switching signals pS2 second control pressure pV supply pressure p1 compressed air supply connection p2 working connection p3 venting p11 first supply connection p12 second supply connection p21 first service brake pressure connection p22 second service brake pressure connection p41 third control connection p42 second control connection p43 first control connection p52 parking brake pressure connection p200 brake pressure connection of the front axle brake pressure modulatorReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2021 122 497 A1

[0005] DE 10 2022 101 142 A1

[0006] DE 10 2021 122 498 A1

[0006] DE 10 2021 122 499 A1

[0006] DE 10 2020 132 875 A1

[0006] EP 3 145 769 B1

[0006]

Claims

Electronically controllable pneumatic brake system (100) for a vehicle (300), in particular commercial vehicle (302), having - at least one first service brake circuit (103) having a first service brake pressure modulator (105), wherein the service brake pressure modulator (105) has at least one first service brake pressure connection (p21) for controlling a service brake pressure (pB) for at least one first service brake actuator (106) of the vehicle (300), and wherein the service brake pressure modulator (105) is connected to a first compressed air supply (108) for receiving supply pressure (pV); - an electronic service brake control unit (ECU1) which is connected to the service brake pressure modulator (105) and provides primary switching signals (PS) at said service brake pressure modulator for switching at least one electromagnetic valve of the first service brake pressure modulator (105); and - a parking brake device (1), a parking brake module (2) having a parking brake pressure connection (p52), wherein the parking brake module (2) is configured to provide a parking brake pressure (pF) at the parking brake pressure connection (p52), and a reversing relay valve (4) for venting at least one first spring brake cylinder (110) of the vehicle (300), wherein the reversing relay valve (4) has a first control connection (p43), a second control connection (p42), a working connection (p2), at least one first reservoir connection (p11) and a vent (p3), wherein the first control connection (p43) is connected to the parking brake pressure connection (p52) for receiving the parking brake pressure (pF), the working connection (p2) is connected to the spring brake cylinder (110), the second control connection (p42) is connected to an electropneumatic valve arrangement (6) for receiving a second control pressure (pS2) different from the service brake pressure (pB), the electropneumatic valve arrangement (6) being actuated by an electronic control unit (ECU2) which is independent of the parking brake module (2), the reversing relay valve (4) being configured to ventilate the spring brake cylinder (110) for a case in which the first control connection (p43) is ventilated, the second control connection (p42) is ventilated and a supply pressure (pV) is applied to the first supply connection (p11), and for a case, in which the first control connection (p43) and the second control connection (p42) are vented and a supply pressure (pv) is applied to the first supply connection (p11) in order to vent the spring brake cylinder (110).Electronically controllable pneumatic brake system (100) according to Claim 1, wherein the reversing relay valve (4) has a third control connection (p41), which is connected to the first service brake pressure connection (p21) for receiving the service brake pressure (pB), wherein the reversing relay valve (4) is configured to ventilate the spring accumulator brake cylinder (110) in the event that the first control connection (p43) and the third control connection (p41) are ventilated, or is ventilated, and a supply pressure (pV) is applied to the first supply connection (p11); In a case in which the first control connection (p43) and the second control connection (p42) are vented, the third control connection (p41) is vented and a supply pressure (pV) is present at the first supply connection (p11), the spring brake cylinder (110) is vented; and in a case in which the second control connection (p43) and the third control connection (p41) are vented, the first control connection (p43) is vented and a supply pressure (pV) is present at the first supply connection (p11), the spring brake cylinder (110) is vented.Electronically controllable pneumatic brake system (100) according to one of the preceding claims, wherein the service brake pressure modulator (105) and the electronic service brake control unit (ECU1) are integrated in one module and are shown as a structural unit.Electronically controllable pneumatic brake system (100) according to one of the preceding claims, wherein the electropneumatic valve arrangement (6) is independent of a service brake function of the electronically controllable pneumatic brake system (100).Electronically controllable pneumatic brake system (100) according to one of the preceding claims, wherein the electropneumatic valve arrangement (6) is bistable and is preferably designed to hold the switching position assumed in the event of a power being omitted.Electronically controllable pneumatic brake system (100) according to one of the preceding claims, wherein the electropneumatic valve arrangement (6) has a relay valve (8), wherein the relay valve (8) has a relay valve supply connection (8.1), a relay valve working connection (8.2) and a relay valve control connection (8.3), wherein the relay valve working connection (8.2) is connected to the second control connection (p42) of the reversing relay valve (4), and wherein the electropneumatic valve arrangement (6) has a first electromagnetic switching valve (SV-A), which is configured to pass, with current, compressed air from the first compressed air supply (108) to the relay valve control connection (8.3).Electronically controllable pneumatic brake system (100) according to Claim 6, wherein the electropneumatic valve arrangement (6) has a second electromagnetic switching valve (SV-B), wherein the second electromagnetic switching valve (SV-B) has a passage position and a venting position, and wherein the second electromagnetic switching valve (SV-B) is in the passage position without current and connects the relay valve working connection (8.2) to the relay valve control connection (8.3).Electronically controllable pneumatic brake system (100) according to Claim 6 or 7, wherein a double supply check valve (10) is arranged upstream of the relay valve supply connection (8.1), and wherein a first double supply check valve inlet (10.1) is connected to the first compressed air supply (108), and a second double supply check valve inlet (10.2) is connected to a second compressed air supply (109).Electronically controllable pneumatic brake system (100) according to one of the preceding claims 6 to 8, wherein the electropneumatic valve arrangement has a select-low valve (SLV) and a pneumatically switchable valve (INV) with a pneumatic control connection (INV.4), wherein the pneumatically switchable valve (INV) has a through-flow position and a venting position, and wherein the select-low valve (SLV) has a first select input (SLV.1), a second select input (SLV.2) and a select output (SLV.3), wherein the first select input (SLV.1) with the pneumatically switchable valve (INV), the second select input (SLV.2) is connected to the first electromagnetic switching valve (SV-A) and the select output (SLV.3) is connected to the relay valve control connection (8.3), and wherein the pneumatically switchable valve (INV) is configured to vent the first select input (SLV.1) in response to a pneumatic control pressure (pnS) at the pneumatic control connection (INV.4).Electronically controllable pneumatic brake system (100) according to Claim 9, wherein the pneumatic control connection (INV.4) of the pneumatically switchable valve (INV) is connected to the first service brake pressure connection (p21) or a brake pressure connection (p200) of a front axle brake pressure modulator (150) or a brake pressure connection of a redundancy brake pressure modulator for receiving a pneumatic control pressure (pnS).Electronically controllable pneumatic brake system (100) according to one of the preceding claims, wherein the first electromagnetic switching valve (SV-A) is connected to the first service brake pressure connection (p21) or a brake pressure connection (p200) of a front axle brake pressure modulator (150) or a brake pressure connection of a redundancy brake pressure modulator, and wherein the first electromagnetic switching valve (SV-A) is configured to pass a brake pressure to the relay valve control connection (8.3) without current.Electronically controllable pneumatic brake system (100) according to claim 11, wherein the electropneumatic valve arrangement (6) has a double ventilation check valve (14), and wherein a first double ventilation check valve inlet (14.1) is connected to the first electromagnetic switching valve (SV-A), wherein a second double ventilation check valve inlet (14.2) is connected to the relay valve working connection (8.2), and wherein a double ventilation check valve outlet (14.3) is connected to the second control connection (p42) of the reversing relay valve (4).Electronically controllable pneumatic brake system (100) according to one of the preceding claims, wherein the reversing relay valve (4) has an open position and a closed position, wherein the reversing relay valve in the open position is configured to release a ventilation path (20) between the first supply connection (p11) and the working connection (p2) for ventilating the spring-loaded brake cylinder (110), and wherein the reversing relay valve (4) in the closed position is configured to release a ventilation path (30) between the working connection (p2) and the ventilation (p3) for ventilating the spring-loaded brake cylinder (110).Electronically controllable pneumatic brake system (100) according to one of the preceding claims, wherein the first supply connection (p11) of the reversing relay valve (4) is connected to the first compressed air supply (108) for supplying the reversing relay valve (4) with compressed air.Electronically controllable pneumatic brake system (100) according to one of the preceding claims, wherein the reversing relay valve (4) has a second supply connection (p12), which is connected to a second compressed air supply (109).Electronically controllable pneumatic brake system (100) according to one of the preceding claims, having a first voltage source (115) for electrically supplying the electronic service brake control unit (ECU1) and a second voltage source (114) for electrically supplying the electronic control unit (ECU2).Electronically controllable pneumatic brake system (100) according to one of the preceding claims, having a redundancy brake pressure modulator and an electronic redundancy brake control unit, wherein the redundancy brake pressure modulator is connected to the electronic redundancy brake control unit and receives secondary switching signals from the latter for switching at least one electromagnetic valve of the redundancy brake pressure modulator, and wherein the electropneumatic valve arrangement (6) is actuated by the electronic redundancy brake control unit.Method for controlling a vehicle (300), in particular commercial vehicle (302), with an electronically controllable pneumatic brake system (100), preferably according to one of the preceding claims, having the steps: - supplying a first supply connection (p11) of a reversing relay valve (4) of a parking brake device (1) with compressed air, wherein the reversing relay valve (4) is configured for venting and venting at least one first spring-loaded brake cylinder (110) of the vehicle (300); - venting a first control connection (p43) of the reversing relay valve (4) with a parking brake pressure (pF) of a parking brake module (2) of the parking brake device (1) such that the spring-loaded brake cylinder (110) is vented; wherein, in an operating case for braking the vehicle (300), a service brake pressure (pB) for at least one first service brake actuator (106) of the vehicle (300) is controlled by a first service brake pressure modulator (105); - wherein, in an error case in which an error has been determined in the parking brake device (1) which at least partially prevents the parking brake pressure (pF) from being controlled, an electropneumatic valve arrangement (6) having an electronic control unit (ECU 2), which is independent of the parking brake module (2), is controlled for ventilating a second control connection (p 42) of the reversing relay valve (4) with a second control pressure (pS 2), such that the spring brake cylinder (110) is vented.Method for controlling a vehicle according to claim 18, wherein for an anti-compound function: - the first supply connection of the reversing relay valve is supplied with compressed air, - the electropneumatic valve arrangement is actuated with the electronic control unit, which is independent of the parking brake module, for ventilating the second control connection of the reversing relay valve with a second control pressure, and - a third control connection of the reversing relay valve, which is connected to a first service brake pressure connection of the service brake pressure modulator, is ventilated with a service brake pressure from the service brake pressure modulator, so that the spring brake cylinder is ventilated.Vehicle (300), in particular commercial vehicle (302), having a front axle, a rear axle (102) and an electronically controllable pneumatic brake system (100) according to one of Claims 1 to 17.Use of a reversing relay valve (4) for supplying and venting at least one first spring-loaded brake cylinder (110) of a vehicle (300), wherein the reversing relay valve (4) has a first control connection (p43), a second control connection (p42), a working connection (p2), at least one first reservoir connection (p11) and a vent (p3), wherein the first control connection (p43) is connected to a parking brake pressure connection (p52) of a parking brake module (2) for receiving a parking brake pressure (pF); and wherein the second control connection (p42) is connected to an electropneumatic valve arrangement (6) for receiving a second control pressure (pS2) different from the service brake pressure (pB), wherein the electropneumatic valve arrangement (6) is actuated by an electronic control unit (ECU2) which is independent of the parking brake module (2).

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