Brake system of a motor vehicle having a permanent brake device

Abstract

The invention discloses a brake system (2) of a motor vehicle, comprising an electropneumatic service brake device (EBS) which comprises at least the following: at least one encoder device (100, 490), which is configured to generate an electrical service brake request signal (150) as a function of a service brake request which represents a target braking force (Fs) or a target braking torque (Ms), and to generate at least one pneumatic control pressure (101, 102); a friction brake having at least one service brake cylinder (14, 24); an electronic controller (490); an electropneumatic valve device (300, 400) which is controlled by the electronic controller (490) as a function of the electrical service brake request signal (150) and which has a quantity-boosting valve (340, 420) having a pneumatic control input (345, 425) and a pneumatic output (18, 380) connected to the at least one service brake cylinder (14, 24); and a first solenoid valve (350, 450), designed in particular as a monostable 2 / 2-way solenoid valve, as a pilot valve for the quantity-boosting valve (340, 420), which is configured to supply the at least one pneumatic control pressure (101, 102) to the pneumatic control input (345, 425) of the quantity-boosting valve (340, 420) in a pass-through position and, in a blocking position, blocks this supply. According to the invention, the brake system (2) further comprises a permanent brake device (4, 19), wherein the electronic controller (490) is configured to determine a maximum possible permanent braking force (Fdmax) or a maximum possible permanent braking torque (Mdmax) by the permanent brake device (4, 19) as a function of the current driving state of the motor vehicle, and to compare the target braking force with the maximum possible permanent braking force or to compare the target braking torque with the maximum possible permanent braking torque, and in particular to exclusively actuate the first solenoid valve (350, 450) in order to switch the first

Description

[0001] 2024PF00046 10.12.2024

[0002] 1

[0003] DESCRIPTION

[0004] Braking system of a motor vehicle with continuous braking device

[0005] The invention relates to a braking system of a motor vehicle, in particular a towing vehicle configured for coupling at least one trailer, comprising an electropneumatic service braking device according to the preamble of claim 1, and to a motor vehicle with a braking system according to claim 17.

[0006] A brake system of this type, known as an EBS brake system, is described, for example, in the Robert Bosch GmbH Automotive Handbook, April 2002, ISBN 3-528-13876-9. The standard EBS brake system comprises a foot brake module, an electronic control unit, two single-channel pressure control modules on the front axle, a dual-channel pressure control module on the rear axle, and a trailer control valve for controlling the trailer brakes. Integrated into each pressure control module, in addition to a relay valve and the inlet / outlet solenoid valve combination that controls it, is a backup solenoid valve. Normally, this backup solenoid valve is energized and in its closed position to hold back the backup control pressure generated by the foot brake module. Only in the event of a fault or failure of the primary electronic control unit does it switch to its open position, allowing the backup control pressure to reach the relay valve so that the relay can then be controlled pneumatically on a secondary basis.However, the construction of such pressure control modules is relatively complex.

[0007] With the increasing electrification of vehicles, commercial vehicles are also being equipped as purely electric vehicles or hybrid vehicles, each with at least one electric motor. This motor is connected to the wheels on one of the vehicle axles, can be operated as a motor and as a generator, and can therefore also be used as a wear-free continuous brake in generator mode. In generator mode, the vehicle's kinetic energy is converted into electrical energy, which can be used to charge an electrical energy storage device in a process called recuperation. 2024PF00046 10.12.2024

[0008] 2

[0009] In addition to their service brakes with hydraulically actuated friction brakes, heavy commercial vehicles are usually also equipped with a wear-free continuous braking system in the form of a hydrodynamic or electrodynamic retarder, which allows the vehicle to decelerate without using the friction brakes. When a retarder is engaged, the vehicle's kinetic energy is converted into heat, which is dissipated into the ambient air by a suitable cooling system. The braking force of a retarder depends on the current driving condition of the commercial vehicle, particularly the vehicle speed or the rotational speed of the drive shaft, for example, the output shaft of a transmission, to which a retarder rotor is connected. A disadvantage of such a retarder, however, is the time delay with which braking force can be built up after a service brake application.Furthermore, a commercial vehicle with a retarder cannot be braked to a standstill, so the friction brakes must be engaged at the latest after reaching or falling below a certain speed threshold.

[0010] The object of the invention is to provide a braking system with an electropneumatic service brake device with friction brakes and a wear-free continuous braking device, which is of simple design. The invention also aims to provide a motor vehicle, in particular a towing vehicle configured for coupling at least one trailer, equipped with such a braking system.

[0011] This problem is solved by the features of claims 1 and 17.

[0012] Further embodiments of the invention are specified in the dependent claims.

[0013] Disclosure of the invention

[0014] The invention presents a braking system for a motor vehicle, in particular a towing vehicle configured for coupling at least one trailer, comprising an electropneumatic service brake device which has at least the following: 2024PF00046 10.12.2024

[0015] 3 a) At least one sensor device configured to generate, depending on a service brake request representing a target braking force or a target braking torque, a1) an electrical service brake request signal, and a2) at least one pneumatic control pressure, b) a friction brake with at least one service brake cylinder, c) an electronic control unit, d) an electropneumatic valve device controlled by the electronic control unit depending on the electrical service brake request signal, comprising d1) a flow-amplifying valve with a pneumatic control input and a pneumatic output connected to the at least one service brake cylinder, and d2) a first solenoid valve, in particular designed as a monostable 2 / 2-way solenoid valve, as a pilot valve for the flow-amplifying valve, which is configured,to supply at least one pneumatic control pressure to the pneumatic control input of the flow-enhancing valve in a flow-through position and to block this supply in a blocking position.

[0016] The sensor device can, in particular, comprise a foot brake module with a foot brake pedal and at least one electrical channel (electrical brake force sensor) in which an electrical signal is generated in an electrical channel dependent on the driver, on which the electrical service brake request signal is based, and in which at least one pneumatic control pressure is generated in at least one pneumatic channel. Alternatively or additionally, the electrical service brake request signal can also be generated by a driver assistance control system or by an autopilot control system.

[0017] The friction brake can, in particular, comprise several wheel friction brakes and also several wheel service brake cylinders, wherein one wheel friction brake, for example a disc brake, is actuated by one wheel service brake cylinder.

[0018] The invention then proposes that 2024PF00046 10.12.2024

[0019] 4 e) the braking system further comprises a continuous braking device, wherein f) the electronic control is configured to f1) determine a maximum possible continuous braking force or a maximum possible continuous braking torque by the continuous braking device depending on the current driving state of the vehicle, and to f2) compare the target braking force with the maximum possible continuous braking force or to compare the target braking torque with the maximum possible continuous braking torque, and to f3) in particular, exclusively actuate the first solenoid valve in order to switch the first solenoid valve to the open position or to the closed position depending on the comparison.

[0020] The first solenoid valve or electropneumatic valve assembly is preferably configured to either maintain the pneumatic control pressure generated by the sensor or allow it to pass through to the flow-boosting valve, but not to reduce it. While the first solenoid valve is connected to the flow-boosting valve like a typical backup solenoid valve of a pressure control module, it is controlled differently from a backup valve, particularly by the electronic control unit. Therefore, the first solenoid valve can maintain the pneumatic control pressure generated by the sensor in the closed position and allow it to pass through in the open position, but it cannot reduce it.A reduction in the pneumatic control pressure is therefore preferably only possible via the sensor device, for example by actuating the foot brake pedal if the sensor device includes a foot brake module. Consequently, the electropneumatic valve device does not require an outlet solenoid valve as is common in pressure control modules, which simplifies the design of the electropneumatic valve device.

[0021] In other words, the electronic control and the electropneumatic valve assembly are configured such that the electronic control only needs to switch or actuate (energize or de-energize) the first solenoid valve of the electropneumatic valve assembly in order to move the first solenoid valve, depending on the comparison, into the open position or into the 2024PF00046 10.12.2024

[0022] 5

[0023] The locking position is switched so that the friction brake is activated or deactivated depending on the comparison. The target braking force or torque is then applied, depending on the comparison, by the friction brake alone, by the continuous braking device and the friction brake, or by the continuous braking device alone. Since such a brake combination requires the electronic control to switch only one solenoid valve of the electropneumatic valve assembly—namely, only the first solenoid valve—the design of the electropneumatic valve assembly is simplified.

[0024] If the electropneumatic valve assembly is designed to include (only) a second, in particular monostable, solenoid valve, which is optionally provided here, then the electropneumatic valve assembly and the electronic control are configured so that switching of this second solenoid valve is omitted during brake biending. This reduces switching wear.

[0025] According to a preferred embodiment, the electropneumatic valve device comprises only the first solenoid valve and the second solenoid valve as solenoid valves.

[0026] The second solenoid valve, which is particularly monostable, can be connected to a compressed air reservoir via a supply port and to the pneumatic control input of the volume-enhancing valve via an output port, and is preferably configured to establish a connection between the pneumatic control port of the volume-enhancing valve and the supply port in a first switching position and to block this connection in a second switching position, wherein the second switching position in particular represents a basic position of the second solenoid valve.

[0027] Preferably, the electropneumatic valve assembly therefore comprises only the first and second solenoid valves as solenoid valves or as pilot valves for the flow-amplifying valve, and is particularly designed as a single unit. This unit preferably integrates at least the first solenoid valve, the second solenoid valve, and the flow-amplifying valve. The flow-amplifying valve is particularly a relay valve or includes one. 2024PF00046 10.12.2024

[0028] 6

[0029] The first solenoid valve and the second solenoid valve can be connected in parallel or in series with respect to the pneumatic control port of the flow-enhancing valve.

[0030] The second solenoid valve can be designed as a 2 / 2-way solenoid valve or as a 3 / 2-way solenoid valve, depending in particular on whether the first solenoid valve and the second solenoid valve are connected in parallel or in series with respect to the pneumatic control port of the flow-enhancing valve in the electropneumatic valve assembly.

[0031] According to a further development, the electronic control unit can be configured to switch the first solenoid valve to the closed position and the second solenoid valve, in particular, exclusively to the first switching position, in order to execute at least one driver assistance function such as electronic stability program (ESP) and / or adaptive cruise control (ACC) and / or hill start assist (HSA), in which the at least one service brake cylinder is vented at least partially independently of the electrical brake request signal and / or the pneumatic control pressure. The optional second solenoid valve of the electropneumatic valve assembly is therefore preferably controlled or switched by the electronic control unit exclusively within the scope of at least one driver assistance function.

[0032] Determining the maximum possible continuous braking force or torque by the continuous braking system, depending on the vehicle's current driving condition, requires the use of sensors to detect parameters such as the vehicle's current speed and transmit corresponding sensor values ​​to the electronic control unit so that it can perform the calculation. Such sensors could include, for example, wheel speed sensors.

[0033] According to one embodiment, the electronic control can be configured to exclusively control the first solenoid valve to a) switch it into the closed position when the target braking force is less than or equal to the maximum possible continuous braking force, or when the target braking torque is less than or equal to the maximum possible continuous braking torque, and to 2024PF00046 10.12.2024

[0034] 7 b) to switch to the through position when the target braking force is greater by a differential braking force in relation to the maximum possible continuous braking force, or when the target braking torque is greater by a differential braking torque in relation to the maximum possible continuous braking torque, such that in particular only the differential braking force or the differential braking torque is generated by venting the at least one service brake cylinder.

[0035] According to further training, the electronic control can be configured to switch the first solenoid valve exclusively between the closed position and the open position in order to modulate the pneumatic control pressure for the quantity-enhancing valve, especially in the sense of a vehicle stability control system such as ASR, ABS and / or ESP.

[0036] The electronic control system can also manage the continuous braking system and the electro-pneumatic service brake system so that the target braking force or torque is primarily generated by the continuous braking system and secondarily by the friction brake. This also reduces wear on the friction brake.

[0037] Preferably, the continuous braking device comprises at least one electric machine connected to the wheels on a vehicle axle, operable at least in generator mode and in particular also in motor mode, and controlled by the electronic control system, which in generator mode brakes the motor vehicle and thereby recharges an electrical energy storage device of the motor vehicle in a recuperative manner, at least partially recovering the kinetic energy of the motor vehicle.

[0038] Alternatively or additionally, the continuous braking device can include a hydrodynamic or electrodynamic retarder, which builds up the continuous braking force or continuous braking torque with a time delay in response to the service brake request.

[0039] Preferably, the braking system can be a) a front axle module assigned to the service brake pressure in service brake cylinders of a front axle of the motor vehicle, and / or 2024PF00046 10.12.2024

[0040] 8 b) comprise a rear axle module assigned to the service brake pressure in service brake cylinders of at least one rear axle of the motor vehicle, and / or b) comprise a trailer control valve (TCV) or trailer control module (TCM) assigned to the brake pressure in brake cylinders of a trailer of the motor vehicle.

[0041] The front axle module and / or the rear axle module can integrate an electropneumatic valve assembly as described above into the trailer control valve (TCV) and / or the trailer control module (TCM), or the front axle module and / or the rear axle module and / or the trailer control valve (TCV) and / or the trailer control module (TCM) can be formed by such an electropneumatic valve assembly. This makes these modules simpler in design than known pressure control modules that perform identical or similar functions, or even more functions.

[0042] For further development, ABS pressure control valves can be installed in the brake lines between the front axle module and the front wheel brake cylinders and / or between the rear axle module and the rear wheel brake cylinders to control the brake pressure at the rear axle individually for each wheel or side by side. These ABS pressure control valves can be controlled by the electronic control unit.

[0043] As an alternative to a rear axle module described above, the braking system can include a pressure control module, in particular a 2-channel module, assigned to the service brake pressure in service brake cylinders of a rear axle of the motor vehicle, which is controlled by the electronic control unit and configured to regulate the service brake pressure at the rear axle.

[0044] In general, a braking force difference AF between the target braking force Fs and the maximum possible continuous braking force Fdmax of the continuous braking device, for example an electric motor and / or a retarder, can be compensated for by at least one module that can actuate the friction brake, controlled by the electronic control unit. This at least one module can optionally be the front axle module, the rear axle module, the pressure control module, and / or the trailer control valve or trailer control module. 2024PF00046 10.12.2024

[0045] 9

[0046] Based on this, the electronic control of the braking system can then be configured so that, in response to the service brake request, it selectively a) controls at least one of the following modules in such a way that only this at least one module generates the target braking force or the target braking torque: a1) The front axle module, and / or a2) the rear axle module or the pressure control module (200, PCM), and / or a3) trailer control valve (TCV) or the trailer control module (TCM), and that b) after the time delay (At) has elapsed, it controls the at least one module in order to reduce the braking force or the braking torque generated by the at least one module, in particular to the extent that the retarder is able to apply a braking force or a braking torque.

[0047] For example, the electronic control unit can activate the front axle module alone, or the front axle module and trailer control valve (TCV), or the trailer control module (TCM) to apply the target braking force or braking torque (alone). After the time delay (At) has elapsed, it can then activate this module or these modules to reduce the braking force or braking torque generated by the module or these modules, particularly to the extent that the retarder is capable of applying a braking force or braking torque. In this procedure, the rear axle module or the pressure control module on the rear axle is therefore not actuated, thus conserving the friction brake on the rear axle.

[0048] Therefore, the electronic control is preferably configured such that, upon receiving a service brake request, it switches the first solenoid valve to the open position only in the at least one module (front axle module and / or rear axle module and / or trailer control valve or trailer control module) by which the target braking force or target braking torque (alone) is generated, and then, after the time delay caused by the retarder as a continuous braking device, it actuates the at least one module to apply the braking force or braking torque generated by the at least one module. 2024PF00046 10.12.2024

[0049] 10 especially to reduce to the extent that the retarder is able to apply a braking force or braking torque.

[0050] This measure compensates for the time-delayed generation of braking force or braking torque by the retarder, because until the time delay expires, the target braking force or torque is applied solely by the pressure control module on the rear axle, or by the pressure control module on the rear axle and the trailer control valve (TCV) or the trailer control module (TCM). Braking of the vehicle with the full target braking force or torque is then guaranteed at all times. After the time delay in the retarder's response to the service brake request has elapsed, a brake bonding process is therefore carried out between the retarder and the pressure control module on the rear axle until the retarder can deliver the target braking force or torque on its own.

[0051] The electronic control can be configured to switch the (optional) second solenoid valve of the electropneumatic valve assembly to the second switching position or to hold it in the second switching position in response to the service brake request, thus blocking the connection between the compressed air supply and the pneumatic control input of the volume-enhancing valve.

[0052] In general, the temporal compensation of the delay At of the retarder with respect to its ability to generate a continuous braking force after its activation by the electronic control can be achieved by activating any of the modules or any combination of modules, in particular the front axle module and / or the rear axle module or the pressure control module and / or the trailer control valve or the trailer control module TCM, in order to generate the target braking force or target braking torque until the time delay At has elapsed (alone) using the friction brake.

[0053] As already indicated above, the first solenoid valve or electropneumatic valve assembly is configured so that it can only maintain or pass through the flow-enhancing valve, but not reduce, the at least one pneumatic control pressure generated by the sensor assembly.

[0054] The electronic control can also be configured to control the continuous braking device in order to increase the braking force generated by the continuous braking device or the braking force from 2024PF00046 10.12.2024

[0055] 11. The braking torque generated by the continuous braking device is reduced when the electronic control system detects that the service brake request and / or the at least one pneumatic control pressure and / or the target braking force or the target braking torque is or has been reduced. This measure takes into account the fact that, as described above, the first solenoid valve or the electropneumatic valve assembly cannot reduce the at least one pneumatic control pressure generated by the sensor. The continuous braking device, controlled by the electronic control system, can then advantageously compensate for this reduction.Therefore, due to the control by the electronic control system, the continuous braking force or the continuous braking torque generated by the continuous braking device is reduced, in particular according to the reduction of the service brake requirement and / or the at least one pneumatic control pressure and / or the target braking force or the target braking torque.

[0056] The invention also relates to a motor vehicle, in particular a towing vehicle configured for coupling at least one trailer, which is equipped with a braking system described above.

[0057] Drawings

[0058] The drawings illustrate exemplary embodiments of the invention. The drawings show

[0059] Fig. 1 shows a schematic representation of a drive train of a motor vehicle which is equipped with a braking system according to a preferred embodiment of the invention, with an electric motor and a retarder;

[0060] Fig. 2 shows a schematic representation of a braking system according to a preferred embodiment of the invention;

[0061] Fig. 3 is a schematic representation of details of the brake system from Fig. 2;

[0062] Fig. 4 shows an embodiment of a front axle module or a trailer control valve or trailer control module of the brake system of Fig. 2; 2024PF00046 10.12.2024

[0063] 12

[0064] Fig. 5 shows another embodiment of a front axle module or a trailer control valve or trailer control module of the brake system of Fig. 2;

[0065] Fig. 6 is a diagram showing the course of the braking force F over time t when the electric machine of Fig. 1 is used as a continuous brake in generator mode during a braking process;

[0066] Fig. 7 shows another diagram in which the course of the braking force FB over time t is shown when the electric machine of Fig. 1 is used as a continuous brake in generator operation during a braking process;

[0067] Fig. 8 shows another diagram in which the course of the braking force FB over time t is shown when the electric machine of Fig. 1 is used as a continuous brake in generator mode during a braking process.

[0068] Fig. 9 is a diagram showing the course of the braking force FB over time t when the retarder of Fig. 1 is used as a continuous brake during a braking process;

[0069] Fig. 10 is a diagram showing the course of the braking force FB over time t when the retarder of Fig. 1 is used as a continuous brake during a braking process.

[0070] Description of the exemplary implementations

[0071] Fig. 1 schematically shows a drive train 1 of a motor vehicle, in particular a towing vehicle configured for pulling or coupling at least one trailer, which is equipped with a braking system 2 according to a preferred embodiment of the invention.

[0072] The drivetrain 1 comprises a rear axle drivetrain with an internal combustion engine, which here, for example, drives the wheels of a rear axle 20, and a front axle drivetrain with an electric motor 4, which here, for example, drives the wheels of a front axle 10 in motor mode and brakes in generator mode. 2024PF00046 10.12.2024

[0073] 13

[0074] The towing vehicle is, for example, a hybrid vehicle that can be driven either by the internal combustion engine 3 and / or the electric motor 4. In the rear axle drivetrain, the internal combustion engine 3 drives the wheels of the rear axle 20 via a clutch 5, a gearbox 6, a driveshaft 7, a first axle differential 8, and two first drive shafts 9. In the front axle drivetrain, the electric motor 4 is connected to the wheels of the rear axle 20 via a drive shaft 11, a second axle differential 12, and two second drive shafts 13, providing either driving or braking power.

[0075] In motor mode, the electric machine 4 is supplied with electrical energy by an electrical energy storage device 22. In generator mode, the electric machine 4 supplies the electrical energy storage device 15 with electrical energy (recuperation), for which the kinetic energy of the towing vehicle and optionally of at least one coupled trailer is used. Therefore, the electric machine 4 can be assigned not only to the drive train 1 but also to the braking system 2 of the towing vehicle and, in this case, represents, for example, part of a continuous braking device of the braking system 2, a further part of which is formed by a hydrodynamic or electrodynamic retarder 19, which is connected to an output shaft 21 of the transmission 6 and thus also to the rear axle drive train.

[0076] Fig. 2 shows, as a preferred embodiment of the brake system 2, an electronic braking system (EBS) according to an embodiment suitable for use in a commercial vehicle such as a (long-haul) truck, a tractor unit (with or without a trailer), a bus, etc. The EBS comprises a foot brake module (FBM) 100, a pressure control module (PCM) 200, and a trailer control valve (TCV) 300. The FBM 100 includes a pneumatic output port 110 and an input interface 130, for example, a foot brake pedal for receiving a service brake request.

[0077] The FBM 100 then generates one or more pneumatic control pressures 101, 102 in one or more pneumatic channels at the one or more pneumatic output ports 110 based on the service brake request (e.g., based on an actuation by the driver). The solid lines connecting the FBM 100 to the trailer control valve TCL 300 and the pressure control module PCM 200 refer to the embodiment with only one pneumatic output port 110, while the dashed lines 2024PF00046 10.12.2024

[0078] The 14 solid lines connecting the FBM 100 with the trailer control valve TCL 300 and the pressure control module PCM 200 refer to the embodiment with two pneumatic output ports 110 providing a first control pressure 101 and a second control pressure 102, one of which controls the trailer control valve TCL 300 and the other the pressure control module PCM 200. The PCM 200 pressure control module comprises a first channel port 210, a second channel port 220, and a pneumatic control port 230. The first channel port 210 provides a first channel output 201, the second channel port 220 provides a second channel output 202, and the pneumatic control port 230 can be connected to the first channel port 210 and / or the second channel port 220 to provide pneumatic control based on the (first or second) control pressure 101, 102 (from the FBM 100).

[0079] The TCV 300 trailer control valve comprises a pneumatic input port 310, an electronic input port 320, a pressure sensor 330, and a trailer coupling port 380 for a trailer, which is connected to a coupling head "brake" for a trailer brake line. In a secondary mode, the pneumatic input port 310 can be connected to one of the pneumatic output ports 110 to pneumatically control the trailer's brake pressure. In another primary mode, the TCV 300 trailer control valve is designed to control the trailer's brake pressure based on an electrical or electronic service brake request signal 150 at an electrical input port 320, with the pressure sensor 330 being used to regulate the brake pressure to a target brake pressure.

[0080] The electrical or electronic service brake request signal 150 can be based on the signal generated by the electrical channel of the foot brake module 100 FBM, which in turn originates from a service brake request by the driver through actuation of the input interface 130. Based on this electrical signal from the foot brake module 100 FBM, the electrical / electronic service brake request signal 150 is then generated, for example, in an electronic control unit 490, such as an electronic brake control unit. Alternatively or additionally, the electrical / electronic service brake request signal 150 can be generated based on an external service brake request. 2024PF00046 10.12.2024

[0081] 15

[0082] The external service brake request, or the electrical service brake request signal, can originate from driver assistance systems such as a vehicle stability function (e.g., ESP, TCS, ABS, ASR) or an assistance system (e.g., ACC, HSA), or from an autopilot system with autonomous driving functions. The FBM 100 foot brake module can generate the electrical service brake request signal(s) in an electrical channel based on the driver actuating an input interface 130, for example, a foot brake pedal. An autonomous driving system can also generate the electronic brake signal(s).

[0083] A cost-effective EBS braking system is preferably implemented here by replacing a pneumatic dual-channel foot brake module (FBM) with a pneumatic single-channel foot brake module (FBM 100) with only one pneumatic channel. The FBM 100 foot brake module, for example, has only one pneumatic channel and one electrical channel. By omitting a second pneumatic channel, costs can be saved (fewer pneumatic lines and valve components are required in the FBM). The same applies to the trailer control valve (TCV 300), which also eliminates one pneumatic control circuit and includes an electrical control circuit to electrically (directly) actuate integrated solenoid valves via the electrical input port 320.

[0084] In another embodiment, instead of a trailer control valve TCV 300, a trailer control module TCM with its own integrated control and regulation electronics can also be present in the brake system 2, wherein the integrated solenoid valves are then controlled by this integrated control and regulation electronics depending on the electrical service brake request signal 150.

[0085] The embodiments are not limited to a foot brake module 100 FBM with only one pneumatic and one electrical channel each. According to further embodiments, the foot brake module 100 FBM can be a pneumatic dual-channel FBM with two pneumatic channels or control circuits, which make it possible to control different axles or the trailer independently of each other.

[0086] Fig. 3 shows further details of a preferred embodiment of the brake system 2 (EBS) of Fig. 2 in a towing vehicle, wherein the foot brake module FBM 100 is shown here 2024PF00046 10.12.2024

[0087] For example, 16 is a foot brake module FBM 100, which has only a single pneumatic channel and therefore only a single output port 110 for the single pneumatic control pressure 101. The exemplary towing vehicle has a front axle 10 (e.g., steered axle) with front axle brake cylinders 14 (on both sides) and at least one rear axle 20 (e.g., driven axle) with rear axle brake cylinders 24 (on both sides). Each brake cylinder 14, 24, or each wheel, can be equipped with corresponding wheel speed sensors 16, 26 to determine the respective wheel speeds on the front axle 10 and / or the at least one rear axle 20. In addition, brake pad wear sensors 17, 27 are installed to determine the respective brake pad wear values ​​on the front axle 10 and / or the at least one rear axle 20.

[0088] The front axle brake cylinders 14 and the rear axle brake cylinders 24, as well as the brake actuators operated by them, such as the disc brakes shown in Fig. 1, form components of a friction brake of the braking system.

[0089] According to the illustrated embodiment, the brake system 2 further comprises a first compressed air reservoir 15 for providing a first supply pressure 115 for the (here only) pneumatic channel of the foot brake module FBM 100, a second compressed air reservoir 25 for providing a second supply pressure 215 for the pressure control module PCM 200, a third compressed air reservoir 35 for providing a third supply pressure 315 for the trailer control valve TCV 300.

[0090] According to the illustrated embodiment, the brake system 2 further comprises a front axle module 400 with an inlet port 410 and a relay valve 420, which is supplied with the first supply pressure 115 from the first compressed air reservoir 15. The inlet port 410 is connected to the pneumatic outlet port 110 of the foot brake module FBM 100 to control brake pressure at the front wheel brake cylinders 14 of the front axle 10. In addition, pressure regulating valves PCV 18 are installed on each side of the front axle 10 between the front axle module 400 and the respective front wheel brake cylinders 14.

[0091] For example, no pressure control valves (PCVs) are installed on the rear axle 20. Instead, the first channel outlet 201 is for one rear wheel brake cylinder 24 on one side of the rear axle 20, and the second channel outlet 202 is for the other rear wheel brake cylinder 24 on the other (opposite) side of the rear axle 2024PF00046 10.12.2024

[0092] 17

[0093] 20 provided. The pressure control module PCM 200 thus controls the brake pressure at the rear axle 20. For this purpose, the pressure control module PCM 200 includes an integrated electronic control unit 270, which is designed to receive the electronic service brake request signal 150 and, on the basis of which, preferably generate side-specific rear wheel brake pressures at the first channel output 201 and the second channel output 202 for the rear wheel brake cylinders 24.

[0094] The PCM 200 pressure control module can further comprise a first pressure sensor 216 for detecting the rear wheel brake pressure at the first channel port 210, a second pressure sensor 226 for detecting the rear wheel brake pressure at the second channel port 220, a first relay valve 217, a second relay valve 227, and an inlet for the second supply pressure 215. Based on the pressure signal from the first pressure sensor 216, which represents the first actual brake pressure, the electronic control unit 270 can regulate a first target brake pressure at the first channel port 210, and based on the pressure signal from the second pressure sensor 226, which represents the second actual brake pressure, it can regulate a second target brake pressure at the second channel port 220.

[0095] The first relay valve 217 and the second relay valve 227 generate these rear wheel brake pressures on the basis of the first supply pressure 115 and the second supply pressure 215 respectively, depending on a pneumatic actuation by an inlet-outlet solenoid valve combination, which is controlled by the integrated electronic control unit 270 depending on the service brake request signal 150.

[0096] Furthermore, embodiments allow stability systems such as ABS and / or ESP and / or TCS to perform wheel-specific braking interventions (brake actuations), for which the determined wheel speed information can be used. To adjust individual brake pressures, the pressure control valves PCV 18 can be used on the front axle 10, and on the rear axle 20, the integrated electronic control unit 270 can independently control the rear brake cylinders 24 via the two channels (first channel output 201 and / or second channel output 202) to adjust individual rear brake pressures for each side.

[0097] Thus, there are two separate service brake circuits: a first service brake circuit for the front axle 10, which includes the front axle modulator 400, and a second 2024PF00046 10.12.2024

[0098] 18

[0099] Service brake circuit for the rear axle 20, which includes the pressure control module PCM 200.

[0100] In addition to the described electronic control, pneumatic control of the service brake pressures on the rear axle is also possible in exemplary embodiments. For this purpose, the pressure control module PCM 200 is configured such that the pneumatic backup port 230 can be connected to the first channel port 210 and / or the second channel port 220 via an integrated backup solenoid valve. These backup solenoid valves, which, for example, open without power in the event of a fault and close when energized under normal circumstances, control the pneumatic control pressure 101 present at the pneumatic backup port 230 up to the pneumatic control ports of the two relay valves 217 and 227 when electrical control by the electronic control unit 270 is not possible. As described above, the pneumatic control pressure 101 is generated by the foot brake module FBM 100.The PCM 200 pressure control module is therefore normally or primarily electrically or electronically controlled by the service brake request signal 150 and secondarily or redundantly by the pneumatic control pressure 101.

[0101] The front axle module 400 and the trailer control valve TCV 300 also offer two independent operating modes. Both the front axle module 400 and the trailer control valve TCV 300 each contain a relay valve 340, 420, which in a first or primary operating mode can be pneumatically controlled by the control pressure 101 received from the FBM 100. The relay valves 340, 420 in the front axle module 400 and in the trailer control valve TCV 300 increase the air volume to achieve sufficient braking effect in the front wheel brake cylinders 14 and in the trailer, respectively.

[0102] In further embodiments, a rear axle module can be arranged on the rear axle 20 instead of the pressure control module PCM 200, which is constructed like the front axle module 400 and then supplies the rear wheel brake cylinders 24 with brake pressure, wherein (ABS) pressure control valves can also be arranged in the brake lines between the rear axle module and the rear wheel brake cylinders 24 in order to be able to control the brake pressure individually for each wheel or side by side.

[0103] The relay valve 340 of the trailer control valve TCV 300 is supplied by the third supply pressure 315, which is present at a supply port 370 2024PF00046 10.12.2024

[0104] 19 supplied with compressed air, and depending on the pneumatic control pressure present at a pneumatic control port 345, 101 controls a trailer brake pressure to a trailer coupling port 380, which is connected to a coupling head “brake”.

[0105] While the front axle module 400 does not require a pressure sensor because the PCV 18 pressure control valves can control individual brake pressures on each side, the trailer control valve TCV 300, for example, includes a pressure sensor 330, which is used in the second or secondary operating mode explained in more detail below. However, the front axle module 400 can also optionally include a pressure sensor.

[0106] The trailer control valve 300 TCV can also be configured for a parking brake function and then have a corresponding input port for requesting a parking brake. Thus, there can be three input ports: a pneumatic input port 310, an electrical input port 320 for electrical / electronic signals, and an input for the parking brake. The parking brake input can be designed to activate the relay valve 340 to provide a parking brake function for the trailer. The parking brake function can activate the brake on the trailer independently of the activation at the pneumatic input port 310 (i.e., independently of the control pressure 101 received, e.g., from the FBM).

[0107] Figures 4 and 5 show both the trailer control valve TCV 300 and the front axle modulator 400. Each enables the pneumatic control described above, in which the control pressure 101 of the foot brake module FBM 100 is used for the pneumatic control of the respective integrated relay valves 340 and 420. This pneumatic control will be used in the first or primary operating mode mentioned above. The second or secondary (backup) operating mode, however, is electronically controlled. For this purpose, the trailer control valve TCV 300 and / or the front axle module 400 includes a first solenoid valve 350 or 450 for opening and / or closing the respective

[0108] Inlet ports 310, 410 and a second solenoid valve 360, 460 for opening and / or closing the respective supply ports 370, 470 (for the third / first supply pressure 315, 115). The first solenoid valve 350, 450 (e.g., designed as a 2 / 2-way solenoid valve) and the second solenoid valve 360, 460 can be configured in a 2024PF00046 10.12.2024

[0109] 20

[0110] The solenoid valves can be arranged in series (see Fig. 4) or in parallel (see Fig. 5). In the series connection of Fig. 4, the second solenoid valve 360, 460 is designed as a 3 / 2-way solenoid valve. In the parallel connection of Fig. 5, the second solenoid valve 360, 460 is also designed as a 2 / 2-way solenoid valve. The series or parallel connection of the two solenoid valves 350, 450 and 360, 460, respectively, is therefore defined by their arrangement in relation to the pneumatic control port 345, 425 of the respective relay valve 340, 420.

[0111] The first solenoid valve 350, 450 can be a monostable valve where the open position is the stable (spring-loaded) default position (e.g., when it is de-energized). Similarly, the second solenoid valve 360, 460 can be a monostable valve where the open position is the stable default position (e.g., when it is de-energized). In this setting, pneumatic control is the primary operating mode.

[0112] The first solenoid valve 350, 450 can therefore function as a holding or releasing valve to decouple the pneumatic inlet port 310, 410 from the pneumatic control port 345, 425 of the relay valve 340, 420 and thus maintain the respective state of the relay valve 340, 420 (holding state) when the second solenoid valve 360, 460 remains in its switching position. The second solenoid valve 360, 460 can be an inlet valve that applies the respective supply pressure 115, 315 to the pneumatic control port 345, 425 of the relay valve 340, 420 (applied state) and thus activates a brake pressure increase in the front wheel brake cylinders 14 and / or at the trailer coupling port 380. The holding position can be used to brake the trailer independently of any action by the driver (e.g., as a stretch brake), while the applied position can be used to set a predetermined braking force when stopped, e.g.to keep the vehicle combination of towing vehicle and trailer stationary.

[0113] The first solenoid valve 350, 450 and the second solenoid valve 360, 460 are controlled by the electronic control unit 490, which can adjust the brake pressure at the front wheel brake cylinders 14 or at the trailer coupling connection 380 based on the electrical / electronic brake signals 150 (i.e., an actuation stage of the foot brake module FBM 100 and / or the external brake request). 2024PF00046 10.12.2024

[0114] 21

[0115] The front axle module 400 and / or the trailer control valve TCV 300 can be designed without their own integrated control unit, which then controls, for example, the first solenoid valve 350, 450 and the second solenoid valve 360, 460 depending on the service brake request signal 150, but can also contain such a unit.

[0116] Preferably, the front axle module 400 and / or the trailer control valve 300 TCV therefore includes the pneumatic relay valve 340, 420 as well as the first and second solenoid valves 350, 360 or 450, 460 and thus enables at least the following functions:

[0117] - Control of the brake pressure output by the relay valve 340, 420 depending on the pneumatic control pressure 101, which is generated here by the pneumatic channel at the pneumatic output port 110 of the foot brake module 100 FBM depending on the driver, when, as shown in Fig. 4 and Fig. 5, the first solenoid valve 350, 420 is switched from the closed position to the open position and the second solenoid valve 360, 460 is switched to or held in the closed position, which includes an increase or decrease of this brake pressure,

[0118] - an increase in the brake pressure output by the relay valve 340, 420 when the second solenoid valve 360, 460 is switched to the open position (supply pressure is allowed through) and the first solenoid valve 350, 450 is switched to the closed position,

[0119] - a blocking or holding function when both solenoid valves 350, 450 and 360, 460 are switched to the blocked position.

[0120] Since there is preferably no venting in the front axle module 400 and / or in the trailer control module TCV 300, the control pressure 101 set by the driver via the input interface 130 represents a lower limit for the control pressure applied to the pneumatic control port of the relay valve 340, 420. The same applies to the trailer brake pressure, which is controlled by the trailer control valve TCV 300 with the same valve arrangement. Like conventional trailer control valves TCV, the TCV 300 can include an integrated parking brake function, but in this case, it only has single-circuit pneumatic control of the service brake functions. Unlike conventional trailer control valves or trailer control modules, 2024PF00046 10.12.2024

[0121] 22 the embodiments therefore do not have two independent pneumatic controls for the service brake functions.

[0122] The FBM 100 is preferably designed as shown in Fig. 2, which also has only a single pneumatic channel and an electrical brake force sensor in an electrical channel for measuring the driver's service brake request and for generating an electrical signal on which the electrical or electronic service brake request signal 150 is based.

[0123] On the other hand, the PCM 200 pressure control module contains an integrated control unit 270 (an electronic control unit, ECU) and a two-channel pressure modulator.

[0124] The embodiments thus offer all the functions of an electronically controlled braking system (EBS). In particular, they can also process external braking requests, e.g., from adaptive cruise control (ACC), hill start assist (HSA), or an autopilot system with autonomous driving functions, which frequently requests axle or trailer brake pressure. Likewise, ESP interventions for targeted braking of the vehicle itself and / or the trailer can be processed accordingly. Furthermore, the electronic control unit 490 can implement load-dependent brake pressures by outputting different service brake request signals 150, depending on the load, to the front axle module 400 on the front axle 10 and to the pressure control module PCM 200 on the rear axle 20.

[0125] Both the retarder 19 and the electric motor 4 operating in generator mode can be actuated by the electronic control unit 490, particularly in response to the service brake request signal 150, to produce a continuous braking effect. For this purpose, these components are connected to the electronic control unit 490 via signal lines (not shown). Due to its design, the retarder 19 reacts to the moment of actuation with a time delay At, after which the continuous braking effect begins. Optionally, the electronic control unit 490 can actuate the retarder 19 and / or the electric motor 4 operating in generator mode as a continuous brake.

[0126] For example, the electronic control unit 490 is configured by implemented algorithms to determine a maximum possible continuous braking force Fd or a maximum possible continuous braking torque Md by the continuous braking device 2024PF00046 10.12.2024

[0127] 23

[0128] (Retarder 19 and / or electric motor 4) depending on the current driving state of the vehicle. The current driving state of the vehicle includes, for example, the current driving speed, which is determined, for example, on the basis of the wheel speed signals from the wheel speed sensors 16, 26, which are already connected to the electronic control unit in order to execute driver assistance functions implemented there.

[0129] The electrical signal, determined by actuation of the input interface 130, and the electrical signal generated in the electrical channel of the foot brake module 100 FBM, or the service brake request signal 150, represent the target braking force Fs or the target braking torque Ms with which the vehicle is to be decelerated. Therefore, a value representing the target braking force Fs or the target braking torque Ms is available to the electronic control unit 490.

[0130] Furthermore, for example, 490 algorithms are stored in the electronic control system, which are used to compare the target braking force Fs with the maximum possible continuous braking force Fd or to compare the target braking torque Ms with the maximum possible continuous braking torque Md.

[0131] For example, the electronic control unit 490 also implements algorithms that exclusively control the first solenoid valve 350, 450 of the front axle module 400 and / or the aforementioned rear axle module (constructed like the front axle module 400) and / or trailer control valve 300 TCV, switching it to the open or closed position depending on the comparison. The second solenoid valve 360, 460, however, is switched to the second switching position by the electronic control unit 490 independently of the comparison, or held in the second switching position, thus blocking the connection between the compressed air supply and the pneumatic control input of the relay valve 340, 420.

[0132] The target braking force Fs or the target braking torque Ms is then applied, depending on the comparison in the sense of a brake combination, by the friction brake alone, by the continuous braking device and by the friction brake, or by the continuous braking device alone. For such a brake combination, switching of only the first solenoid valve 350, 450 by the electronic control unit 490 is therefore provided. 2024PF00046 10.12.2024

[0133] 24

[0134] This procedure, implemented in the electronic control unit 490, will be explained below using examples.

[0135] Fig. 6 shows, as an example, a diagram in which the course of the braking force FB over time t is shown when the electric machine 4 of Fig. 1 is used as a continuous brake in generator operation during a braking process.

[0136] Figure 6 indicates:

[0137] - the solid line represents the target braking force Fs according to the service brake requirement, which here, for example, is entered into the foot brake module 100 FBM via interface 130,

[0138] - the dashed line represents, for example, the maximum continuous braking force Fdmax that can be applied by the electric machine 4 in generator mode, in relation to the current driving state of the motor vehicle, which is ideally assumed to be constant over time t,

[0139] - the dotted line represents the time course of the continuous braking force Fd applied by the electric machine 4 in generator operation, and

[0140] - the dashed line represents the time course of the braking force F, which the friction brake applies here, for example, via the front axle module 400, the pressure control module 200 PCM and the trailer control valve 300 TCV.

[0141] At time tO, the service brake actuation signal 150 is generated, whereupon the electronic control unit 490 switches the first solenoid valve 350, 450 in the front axle module 400 and in the trailer control valve 300 TCV to the closed position or holds it in the closed position, for example by energizing it, because it has determined that at this time tO the target braking force Fs can be applied solely by the electric motor 4 in generator mode. The second solenoid valve 360, 460 in these modules 400, 300 is held in the second switching position by the electronic control unit 490, so that the pneumatic control connection 345, 425 of the relay valve 340, 420 cannot be pressurized by the respective compressed air reservoir 15 or 35. The electronic control unit 490 also omits (initially) the activation of the pressure control module 200 PCM to generate brake pressures in the rear wheel brake cylinders 24. 2024PF00046 10.12.2024

[0142] 25

[0143] The friction brake, which can be actuated here by the front axle module 400, the pressure control module 200 PCM and / or the trailer control valve 300 TCV, therefore remains deactivated for the time being.

[0144] At time t1, the time course of the target braking force Fs intersects the time course of the maximum continuous braking force Fdmax that can be applied by the electric machine 4, so that the limit of the continuous brake is reached.

[0145] From time t1 onwards, the friction brake of the continuous brake must therefore be engaged to meet the increasing service brake demand from this point onwards. The electronic control unit 490 then calculates the additional braking force required by the friction brake as the difference between the target braking force Fs and the maximum possible continuous braking force Fdmax, which must then be provided by the friction brake as compensation.

[0146] At time t2, the electronic control unit activates the friction brake, for example by switching the first solenoid valve 350, 450 of the front axle module 400 and also the trailer control valve 300 TCV to the open position, specifically by allowing air to flow. This enables the pneumatic control pressure 101 generated in the foot brake module 100 FBM to be applied to the pneumatic control port 345, 425 of the respective relay valve 340, 420, thus generating brake pressure in the front axle brake cylinders 14 and in the trailer brake cylinders. Simultaneously, the electronic control unit can also activate the pressure control module 200 PCM to generate brake pressure in the rear wheel brake cylinders 24.

[0147] The second solenoid valve 360, 460 in the modules 400, 300 is preferably held in the second switching position by the electronic control 490 at all times.

[0148] Fig. 7 shows another example, a further diagram illustrating the braking force FB over time t when the electric machine from Fig. 1 is used in generator mode during a braking process. The solid, dotted, dashed, and dash-dotted lines each represent the curve already described above for Fig. 6. 2024PF00046 10.12.2024

[0149] 26

[0150] The brake request is also to occur at time tO, at which time the first solenoid valve 350, 450 of the front axle module 400 and the trailer control valve 300 TCV is held in the closed position, for example, by energizing it. The second solenoid valve 360, 460 in these modules 400, 300 is held in the second switching position by the electronic control unit 490, so that the pneumatic control connection 345, 425 of the relay valve 340, 420 cannot be pressurized by the respective compressed air reservoir 15 or 35. Furthermore, the pressure control module 200 PCM for generating brake pressures in the rear wheel brake cylinders 24 is (initially) not activated by the electronic control unit 490. This is because the maximum continuous braking force Fdmax that can be applied by the electric machine 4 in generator operation is still sufficient at time tO to apply the target braking force on its own.

[0151] In contrast to Fig. 6, here, for example, the maximum continuous braking force Fdmax that can be applied by the electric machine 4 in generator operation is greater than the target braking force Fs at least until time t2, so that the electronic control 490 must temporarily reduce the continuous braking force Fd of the electric motor 4 in order to adapt it to the target braking force Fs.

[0152] Let us now assume that at time t1 the maximum continuous braking force Fdmax that can be applied by the electric machine 4 in generator mode is reduced, for example because the vehicle's speed has (significantly) decreased. Then, from time t2 onwards, the friction brake must be engaged by the electronic control unit. This engagement essentially results in the same control actions by the electronic control unit 490 as already described in Fig. 6 for the first solenoid valve 350, 450 and the second solenoid valve 360, 460 and the pressure control module 200 PCM, in order to activate the friction brake to compensate for the insufficient continuous braking force Fd.Therefore, here too, only the first solenoid valve 350, 450 in the front axle module and in the trailer control valve 300 TCV is switched to the open position, for example by a respective discharge, while the second switching position of the second solenoid valve 360, 460, which was already in the initial position, remains unchanged. 2024PF00046 10.12.2024.

[0153] 27

[0154] It is clear that the compensation of the braking force difference AF between the target braking force Fs and the maximum possible continuous braking force Fdmax of the continuous braking device, here for example the electric motor 4, can be carried out by at least one module that can actuate the friction brake, controlled by the electronic control unit 490. This at least one module can optionally be the front axle module 400, the pressure control module 200 PCM and / or the trailer control valve 300 TCV.

[0155] Fig. 8 shows a diagram in which the course of the braking force FB over time t is shown when the electric machine 4 of Fig. 1 is used as a continuous brake during a braking process.

[0156] Figure 8 indicates:

[0157] - the solid line represents the target braking force Fs according to the service brake requirement, which here, for example, is entered into the foot brake module 100 FBM via interface 130,

[0158] - the dashed line represents, for example, the maximum continuous braking force Fdmax that can be applied by the electric machine 4 in generator mode, in relation to the current driving state of the motor vehicle, which is ideally assumed to be constant over time t,

[0159] - the dotted line represents the time course of the continuous braking force Fd applied by the electric machine 4 in generator operation, and

[0160] - the dashed line represents the time course of the braking force F, which the friction brake applies here, for example, via the front axle module 400, the pressure control module 200 PCM and the trailer control valve 300 TCV.

[0161] At time tO, the service brake actuation signal 150 is generated, whereupon the electronic control unit 490 switches the first solenoid valve 350, 450 in the front axle module 400 and in the trailer control valve 300 TCV to the closed position or holds it in the closed position, for example by energizing it, because it has determined that at this time tO the target braking force Fs can be applied solely by the continuous braking force Fd generated by the electric motor 4 in generator mode. The second solenoid valve 360, 460 in these modules 400, 300 is held in the second switching position by the electronic control unit 490, so that the pneumatic 2024PF00046 10.12.2024

[0162] 28

[0163] Control ports 345, 425 of relay valves 340, 420 cannot be vented by the respective compressed air reservoir 15 or 35. Furthermore, the electronic control unit 490 does not (initially) activate the pressure control module 200 PCM to generate brake pressures in the rear wheel brake cylinders 24.

[0164] The friction brake, which can be actuated here by the front axle module 400, the pressure control module 200 PCM and / or the trailer control valve 300 TCV, therefore remains deactivated for the time being.

[0165] At time t1, the time course of the target braking force Fs intersects the time course of the maximum continuous braking force Fdmax that can be applied by the electric machine 4, so that the limit of the continuous brake is reached.

[0166] From time t1 onwards, the friction brake of the continuous brake must therefore be engaged to meet the increasing service brake demand from this point onwards. The electronic control unit 490 then calculates the additional braking force required by the friction brake as the difference between the target braking force Fs and the maximum possible continuous braking force Fdmax, which must then be applied compensatorily by the friction brake as the braking force Fr of the friction brake.

[0167] At time t2, the electronic control unit activates the friction brake, for example by switching the first solenoid valve 350, 450 of the front axle module 400 and also the trailer control valve 300 TCV to the open position, specifically by allowing air to flow. This enables the pneumatic control pressure 101 generated in the foot brake module 100 FBM to be applied to the pneumatic control port 345, 425 of the respective relay valve 340, 420, thus generating brake pressure in the front axle brake cylinders 14 and in the trailer brake cylinders. Simultaneously, the electronic control unit can also activate the pressure control module 200 PCM to generate brake pressure in the rear wheel brake cylinders 24. The second solenoid valve 360, 460 in the modules 400, 300 is preferably held in the second switching position by the electronic control 490 at all times.

[0168] At time t2b, the total braking force Fg, as the sum of the continuous braking force Fd and the braking force Fr of the friction brake, corresponds to the target braking force 2024PF00046 10.12.2024

[0169] 29

[0170] Fs, whereby the first solenoid valve 350, 450 is then switched into the closed position, for example by energizing it.

[0171] At time t3, the driver reduces the service brake request via interface 130, which corresponds to a reduction in the target braking force Fs. From time t4 onwards, the continuous braking force Fd is reduced, for example, to the same extent as the target braking force Fs is reduced, since neither the first solenoid valve 350, 450 nor the second solenoid valve 360, 460 are configured and controllable to reduce the control pressure 101. Although a reduction in the partial braking force Fr applied by the pressure control module 200 PCM would be possible here, this case will not be considered for the example illustrated. Therefore, the control pressure 101 is "locked in" or held by the first solenoid valve 350, 450, which is switched to the closed position, so that the braking force Fr of the friction brake remains (initially) constant even after time t3.The reduction of the target braking force Fs is then achieved, for example, solely by a corresponding reduction of the continuous braking force Fd. At time t5, the continuous braking force Fd applied by the continuous brake, here for example by the electric machine 4 in generator mode, is reduced to zero in order to adjust the total braking force Fg, consisting of the continuous braking force Fd and the braking force Fr of the friction brake, to the further decreasing target braking force Fs.

[0172] It is understood that, in relation to this example, instead of or in addition to the electric machine 4, the retarder 19 could also be controlled accordingly by the electronic control unit 490 in order to reduce the continuous braking force Fd.

[0173] Fig. 9 shows a diagram in which the course of the braking force FB over time t is shown when the retarder 19 of Fig. 1 is used as a continuous brake during a braking process.

[0174] Figure 9 indicates:

[0175] - the solid line represents the target braking force Fs according to the service brake requirement, which here, for example, is entered into the foot brake module 100 FBM via interface 130,

[0176] - the dashed line represents the braking force F applied by the friction brake, here for example solely by the pressure control module 200 PCM via control by the electronic control unit 490, 2024PF00046 10.12.2024

[0177] 30

[0178] - the dotted line represents the time course of the continuous braking force Fd applied by the retarder 19, which, due to its design, only becomes effective after a time delay At, and

[0179] - the dashed line represents the time course of the braking force F, which the friction brake applies here, for example, via the front axle module 400 and the trailer control valve 300 TCV.

[0180] At time tO, the service brake actuation signal 150 is generated, whereupon the electronic control unit 490 switches the first solenoid valve 350, 450 in the front axle module 400 and in the trailer control valve 300 TCV to the closed position or holds it in the closed position, for example by energizing it. The second solenoid valve 360, 460 in these modules 400, 300 is held in the second switching position by the electronic control unit 490, so that the pneumatic control connection 345, 425 of the relay valve 340, 420 cannot be pressurized by the respective compressed air reservoir 15 or 35.

[0181] At time tO, the electronic control unit also activates the retarder 19 to generate a continuous braking force Fd. However, due to the time delay At, the retarder 19 can only begin building up the continuous braking force Fd at the later time t1.

[0182] To bridge this time delay At, the pressure control module 200 PCM on the rear axle 20 is, for example, controlled by the electronic control at time tO to generate a brake pressure in the rear wheel brake cylinders 24, which preferably applies the entire target braking force Fs there, until the retarder 19 can begin building up the continuous braking force Fd at the later time t1.

[0183] From time t1, the electronic control unit 490 reduces the brake pressure acting in the rear wheel brake cylinders 24 by controlling, for example, the pressure control module 200 PCM, in order to reduce the braking force F acting there, to the extent that the retarder 19 is able to apply the continuous braking force Fd from time t1. This means that, for example, from time t1, the target braking force Fs is the sum of the time-increasing continuous braking force Fd that can be applied by the retarder 19 and the 2024PF00046 10.12.2024

[0184] 31 time decreasing braking force F of the friction brake, which is generated by the pressure control module 200 PCM on the rear axle 20.

[0185] Activating the pressure control module 200 PCM on the rear axle 20 therefore compensates for the time delay At that lies between the activation of the retarder at time tO and the onset of the continuous braking force Fd by the retarder 19 at time t1. It is clear that this time compensation can be achieved by any of the modules or by any combination of modules, including, in particular, the front axle module 400 and / or the trailer control valve 300 TCV, or even by all modules 200, 300, and 400.

[0186] In general, i.e., with regard to the entire time course t, in the embodiment described with reference to Fig. 9, the electronic control unit does not activate the front axle module 400 and the trailer control valve 300 TCV; that is, the first solenoid valve 350, 450 in the front axle module 400 and in the trailer control valve 300 TCV is held in the closed position by the electronic control unit 490, for example by energizing it. The second solenoid valve 360, 460 is also held in the second switching position at all times.

[0187] Fig. 10 shows another diagram illustrating the braking force FB over time t when the retarder 19 from Fig. 1 is used during a braking process. The solid, dotted, dashed, and dash-dotted lines each represent the curve already described above for Fig. 9.

[0188] In contrast to the example in Fig. 8, after time tO the target braking force Fs exceeds the braking force F that can be applied by the pressure control module 200 PCM, so that from time t01 the front axle module 400 and, for example, also the trailer control valve TCV are activated by the electronic control unit 490 to apply the remaining differential force AF to the target braking force. This activation is effected by switching the respective first solenoid valve 350, 450 to the open position, here for example by allowing flow, while the respective second solenoid valve 360, 460 remains in the second switching position.

[0189] After the time delay At has elapsed, after which the retarder 19 can only begin to build up the continuous braking force Fd at time t1, 2024PF00046 then controls 10.12.2024

[0190] 32 The electronic control unit 490, for example, only activates the pressure control module 200 PCM on the rear axle 20 to reduce the brake pressure and thus the braking force F applied by it to the extent that the retarder is able to increase the continuous braking force Fd over time t. In contrast, the braking force F applied by the front axle module 400 and the trailer control module, for example, remains constant.

[0191] The examples above demonstrate that by activating (energizing or de-energizing) or changing the switching state of only the first solenoid valve 350, 450 in the front axle module 400 and / or in the trailer control module 300 TCV, the friction brake can be activated by a brake pressure or pressures which are at most as high as the maximum brake pressure generated in the relay valve 340, 420 based on the control pressure 101. For higher brake pressures, the second solenoid valve 360, 460 in the front axle module 400 and / or in the trailer control module 300 TCV can be switched to the first switching position instead or additionally.

[0192] The electro-pneumatic valve assembly integrated in the front axle module 400 and / or in the trailer control module 300 TCV, consisting of the first solenoid valve 350, 450, the second solenoid valve 360, 460 as pilot valves and the relay valve 340, 420, can then be used to generate the braking force component AF in the sense of compensation, which corresponds to a difference between the target braking force Fs and a continuous braking force Fd or the maximum possible continuous braking force Fdmax of a continuous braking device.

[0193] Overall, the electropneumatic valve assembly, consisting of the first solenoid valve 350, 450, the second solenoid valve 360, 460 as pilot valves, and the relay valve 340, 420, allows for the creation of simple modules 300, 400, which then use the friction brake compensatorily in relation to the continuous brake, with minimal switching effort required from the solenoid valves. 2024PF00046 10.12.2024

[0194] 33

[0195] LIST OF REFERENCE MARKS

[0196] 1 Powertrain

[0197] 2 Brake system

[0198] 3 Internal combustion engine

[0199] 4 Electric machine

[0200] 5 Clutch

[0201] 6 gearboxes

[0202] 7 Cardan shaft

[0203] 8 first axle differential

[0204] 9 first drive shafts

[0205] 10 Front axle

[0206] 11 Drive shaft

[0207] 12 second axle differential

[0208] 13 second drive shafts

[0209] 14 front wheel brake cylinders

[0210] 15 first compressed air storage

[0211] 16. 26 wheel speed sensors

[0212] 17. 27 Brake pad wear sensors

[0213] 18 Pressure Control Valve(s) (PCV)

[0214] 19 Retarder

[0215] 20 Rear axle

[0216] 21 Output shaft gearbox

[0217] 22 electrical energy storage devices

[0218] 24 rear wheel brake cylinders

[0219] 25 second compressed air reservoir

[0220] 35 third compressed air storage tank 2024PF00046 10.12.2024

[0221] 34

[0222] 100 Foot Brake Module (FBM)

[0223] 101, 102 Tax pressure(s)

[0224] 110, 111, 112 pneumatic output connections

[0225] 115, 215, 315 supply pressures

[0226] 121, 122 first and second pressure control circuits

[0227] 130 Input interface

[0228] 150 electrical / electronic brake request signal

[0229] 200 Pressure Control Module (PCM)

[0230] 201 first channel output

[0231] 202 Second channel output

[0232] 210 first canal connection

[0233] 215 second supply pressure

[0234] 220 second channel connection

[0235] 216, 226 pressure sensors

[0236] 217, 227 Relay valves

[0237] 230 pneumatic backup connection

[0238] 270 electronic controller (ECU)

[0239] 300 Trailer Control Valve (TCV)

[0240] 310 pneumatic inlet connection

[0241] 320 electrical input connection

[0242] 330,430 pressure sensors

[0243] 340 Relay valve

[0244] 345 pneumatic control connection

[0245] 350 first solenoid valve

[0246] 360 second solenoid valve

[0247] 365 third solenoid valve 2024PF00046 10.12.2024

[0248] 35

[0249] 370 Supply connection

[0250] 380 Trailer hitch connection

[0251] 385 Supply connection

[0252] 390 monostable pneumatic valve

[0253] 400 Front axle module

[0254] 410 Input connection

[0255] 420 Relay valve

[0256] 425 Control connection

[0257] 450 first solenoid valve

[0258] 460 second solenoid valve

[0259] 470 Supply connection

[0260] 490 electronic control

[0261] At time delay of the retarder

[0262] FB Braking force

[0263] Fd continuous braking force

[0264] Fr Braking force of the friction brake

[0265] Fg Total braking force as the sum of the continuous braking force Fd and the

[0266] Braking force Fr of the friction brake

[0267] Md continuous braking torque

[0268] Fdmax maximum applicable continuous braking force

[0269] Mdmax maximum continuous braking torque

[0270] Fs target braking force

[0271] Ms target braking torque

Claims

2024PF00046 10.12.2024 36 PATENTANSPRÜCHE 1. Braking system (2) of a motor vehicle, in particular of a towing vehicle configured for coupling at least one trailer, comprising an electropneumatic service brake system (EBS) which has at least the following: a) At least one sensor device (100, 490) configured to generate, depending on a service brake request representing a target braking force (Fs) or a target braking torque (Ms), a1) an electrical service brake request signal (150), and a2) at least one pneumatic control pressure (101, 102), b) a friction brake with at least one service brake cylinder (14, 24), c) an electronic control unit (490), d) an electropneumatic valve device (300, 400) controlled by the electronic control unit (490) depending on the electrical service brake request signal (150), which d1) a flow-enhancing valve (340, 420) with a pneumatic control input (345, 425) and a pneumatic output (18,380) which is connected to the at least one service brake cylinder (14, 24), and d2) a first solenoid valve (350, 450) which is designed in particular as a monostable 2 / 2-way solenoid valve as a pilot valve for the volume-amplifying valve (340, 420), which is configured to supply the at least one pneumatic control pressure (101, 102) to the pneumatic control input (345, 425) of the volume-amplifying valve (340, 420) in a flow-through position and to block this supply in a blocking position, characterized in that e) the brake system (2) further comprises a continuous braking device (4, 19), wherein f) the electronic control (490) is configured to f1) determine a maximum possible continuous braking force (Fdmax) or a maximum possible continuous braking torque (Mdmax) by the continuous braking device (4, 19) depending on the current driving condition of the motor vehicle,and for f2) comparing the target braking force with the maximum possible continuous braking force or comparing the target braking torque with the maximum possible continuous braking torque, and for f3) in particular exclusively controlling the first solenoid valve (350, 450) in order to switch the first solenoid valve (350, 450) to the open position or to the closed position depending on the comparison. 2024PF00046 10.12.2024 37 2. Braking system according to claim 1, characterized in that the electronic control (490) is configured to control, in particular, only the first solenoid valve (350, 450) to a) switch it to the closed position when the target braking force (Fs) is less than or equal to the maximum possible continuous braking force (Fdmax), or when the target braking torque (Ms) is less than or equal to the maximum possible continuous braking torque (Mdmax), and to b) switch it to the open position when the target braking force (Fs) is greater than the maximum possible continuous braking force (Fdmax) by a differential braking force (AF), or when the target braking torque (Ms) is greater than the maximum possible continuous braking torque (Mdmax) by a differential braking torque (AM), such that, in particular, only the differential braking force (AF) or the differential braking torque (AM) is affected by a pressure increase. of at least one service brake cylinder (14, 24) is generated.

3. Brake system according to one of the preceding claims, characterized in that the electronic control (490) is configured to switch, in particular, the first solenoid valve (350, 450) exclusively between the closed position and the open position in order to modulate the pneumatic control pressure for the quantity-enhancing valve (340, 420).

4. Brake system according to one of the preceding claims, characterized in that the electropneumatic valve device (300, 400) comprises a second solenoid valve (360, 460), which is connected on one side to at least one compressed air reservoir (15, 35) via a supply port (370, 470) and on the other side to the pneumatic control input (345, 425) of the volume-enhancing valve (340, 420) via an output port, and which is configured to establish a connection between the pneumatic control port (345, 425) of the volume-enhancing valve (340, 420) and the supply port (370, 470) in a first switching position and to block this connection in a second switching position, wherein in particular the second switching position represents a basic position of the second solenoid valve (360, 460).

5. Brake system according to claim 4, characterized in that the electropneumatic valve assembly (300, 400) is configured as solenoid valves or as pilot valves for the 2024PF00046 10.12.2024 38 quantity-enhancing valve (340, 420) comprises only the first solenoid valve (350, 450) and the second solenoid valve (360, 460) and is designed in particular as a unit.

6. Brake system according to claim 4 or 5, characterized in that the first solenoid valve (350, 450) and the second solenoid valve (360, 460) are connected in parallel or in series with respect to the pneumatic control port (345, 425) of the quantity-enhancing valve (340, 420).

7. Brake system according to one of claims 4 to 6, characterized in that the electronic control unit (ECU) is configured to switch the first solenoid valve (350, 450) to the blocking position and the second solenoid valve (360, 460) in particular exclusively to the first switching position in order to perform a driver assistance function such as electronic stability program (ESP), adaptive cruise control (ACC) and / or hill start assist (HSA), in which at least one The service brake cylinder (14, 24) is vented at least partially independently of the service brake request signal (150) and / or the pneumatic control pressure (101, 102).

8. Braking system according to one of the preceding claims, characterized in that the electronic control (490) controls the continuous braking device (4, 19) and the electro-pneumatic service braking device (EBS), and that the target braking force or target braking torque is generated primarily by the continuous braking device (4, 19) and secondarily by the friction brake.

9. Braking system according to one of the preceding claims, characterized in that the continuous braking device comprises at least one electric machine (4) which is in drive connection with the wheels on a vehicle axle, which can be operated at least in generator mode and in particular also in motor mode and which is controlled by the electronic control (490), which in generator mode brakes the motor vehicle and thereby recharges an electrical energy storage device (22) of the motor vehicle in a recuperative manner with at least partial recovery of the kinetic energy of the motor vehicle.

10. Braking system according to one of the preceding claims, characterized in that the continuous braking device has a hydrodynamic or electrodynamic 2024PF00046 10.12.2024 39 Retarder (19) includes which, in response to the service brake request, builds up the continuous braking force or the continuous braking torque with a time delay (At).

11. Brake system according to one of the preceding claims, characterized in that it comprises a) a front axle module (400) assigned to the service brake pressure in service brake cylinders (14) of a front axle (10) of the motor vehicle, and / or b) a rear axle module assigned to the service brake pressure in service brake cylinders (24) of a rear axle (20) of the motor vehicle, and / or c) a trailer control valve (300, TCV) or trailer control module (TCM) assigned to the brake pressure in brake cylinders of a trailer of the motor vehicle, in which the electropneumatic valve device (300, 400) is integrated.

12. Brake system according to one of the preceding claims, characterized in that it comprises a pressure control module (200, PGM) in particular a 2-channel pressure control module (200, PGM) assigned to the service brake pressure in service brake cylinders (24) of a rear axle (20) of the motor vehicle, which is controlled by the electronic control unit (490) and is configured to control the service brake pressure at the rear axle (20).

13. Braking system according to claims 10 to 12, characterized in that the electronic control (490) is configured to selectively a) control at least one of the following modules in response to the service brake request such that only this at least one module generates the target braking force or the target braking torque: a1) The front axle module (400), and / or a2) the rear axle module or the pressure control module (200, PGM), and / or a3) trailer control valve (TCV) or the trailer control module (TCM), and that b) after the time delay (At) has elapsed, it controls the at least one module in order to reduce the braking force or the braking torque generated by the at least one module, in particular to the extent that the retarder (19) is able to apply a braking force or a braking torque.

14. Brake system according to one of claims 4 to 7 and according to claim 13, characterized in that the electronic control (490) is configured to activate the second solenoid valve (360, 460) in response to the service brake request. 2024PF00046 10.12.2024 40 electropneumatic valve device (300, 400) switches to the second switching position or holds in the second switching position.

15. Brake system according to one of the preceding claims, characterized in that the first solenoid valve (350, 450) and / or the electropneumatic valve assembly is configured such that it can only maintain or allow the pneumatic control pressure (101, 102) generated by the sensor device (100, FBM) to pass through to the quantity-enhancing valve (340, 420), but cannot reduce it.

16. Brake system according to claim 15, characterized in that the electronic control (490) is configured to actuate the continuous braking device (4, 19) to reduce the braking force (Fd) or braking torque (Md) generated by the continuous braking device (4, 19) when the electronic control (490) detects that the service brake request and / or the at least one pneumatic control pressure (101, 102) and / or the target braking force (Fs) or target braking torque (Ms) is reduced or has been reduced.

17. Motor vehicle, in particular a towing vehicle configured for coupling at least one trailer, characterized in that it is equipped with a braking system (2) according to at least one of the preceding claims.

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