Method for determining brake pressure and brake device actuated with pressure medium

Abstract

The invention relates to a method for determining or estimating a first brake pressure (p1) for a first brake actuator (4) for at least one first wheel (1A), said first brake actuator comprising a pressure-medium-actuated brake device (80), a brake pressure needs to be established on the first wheel during a braking process and / or during the implementation of a control for processing a wheel speed signal, and a first wheel speed sensor is absent on the first wheel, although the first wheel rotational speed sensor (5A) is present, the first wheel rotational speed signal (n1) is not provided or the error-free first wheel rotational speed signal is not provided, the method comprises at least the following steps: a) determining, measuring or estimating a second brake pressure (p2) for a second brake actuator (4) of at least one second wheel (1B), the brake device (80) comprising the second brake actuator, during the braking process and / or during the implementation of the control, a second wheel rotational speed sensor (5b) is associated with the second wheel, which second wheel rotational speed sensor provides a wheel rotational speed signal (n2), and b) the first brake pressure (p1) is determined or estimated as a function of the second brake pressure (p2).

Description

Technical Field

[0001] The invention relates to a method for controlling a braking device of a vehicle according to claim 1 and to a braking device of a vehicle according to claim 15 . Background Art

[0002] Modern brake systems include a vehicle dynamics control system, which includes functions such as drive slip control (ASR), anti-lock braking system (ABS) and / or electronic stability program (ESP). The invention relates to an ESP controller for a motor vehicle, which has hierarchically organized basic functions, which include at least one vehicle dynamics controller (GMR) and an anti-lock braking system (ABS or ABSplus), and which can have further basic functions or systems, such as ASR, MSR, EBV, ICC, BA, etc., wherein the vehicle dynamics controller (GMR controller) is the superior of the other basic functions or systems and calculates an additional yaw moment (ΔM).

[0003] There is also a requirement for redundant design of the vehicle dynamics control system. In other words, even in the event of a functional loss of the vehicle dynamics control system, at least preliminary vehicle dynamics control should still be possible, so that the vehicle stability or deceleration capability can be at least partially maintained. In particular, vehicles with (partial) automated driving functions relieve the driver of driving tasks and driving responsibilities at least for a limited time, i.e., can be operated autonomously, and the vehicle must be able to continue driving the vehicle in the event of any fault until the driver takes over the vehicle again. The resulting system characteristic "fail-operable" requires that the basic functions of the vehicle must be ensured, especially at the implementation level, at least with functional restrictions. For brake control in autonomous driving operation, this means that in the event of any fault, the service brake device must still be able to be operated in an electronically controlled manner, so that the vehicle dynamics control functions (such as ABS, ASR and ESP) can still be implemented, although possibly with restrictions.

[0004] In this context, driving dynamics control systems and ABS in particular are very important. Thus, high requirements are placed on ABS in terms of its availability. That is, in conventional vehicles, ABS can be simply turned off in the event of a fault and the driver can be made aware of the turn-off in order to urge the driver to drive more carefully. In the case of autonomous or semi-autonomous driving, the vehicle system remains fully responsible for a long period of time or even permanently. A common fault condition that causes ABS to turn off in conventional vehicles is the failure of the wheel signal, which is used by ABS for slip detection and slip regulation on the corresponding vehicle wheels. In order to prevent this fault condition, the corresponding wheel sensor device (possibly including the input line) can be designed redundantly. However, this redundancy brings high costs. Alternatively, in the case of failure of the wheel signal for the front wheels, for example, the regulation on the wheels of the front axle can be turned off and concentrated on the wheels of the rear axle in order to at least prevent oversteering. However, in many cases, such as in the case of autonomous or semi-autonomous driving, the stability limitation caused by this solution is unacceptable.

[0005] Although redundancy of all components of an electropneumatic service brake system for the purpose of creating complete redundancy is effective in order to achieve functionality even in the event of a fault, it is disadvantageous in terms of costs, installation space and weight, especially in terms of mass production. Summary of the invention

[0006] The invention is based on the object of specifying a technical solution which is not susceptible to failures of the wheel signals.

[0007] This object is achieved according to the invention by the features of claims 1 and 15 .

[0008] According to a first aspect of the invention, a method is provided for determining or estimating a first brake pressure of a first brake actuator for at least one first wheel, a brake device actuated by a pressure medium comprising the first brake actuator, a brake pressure buildup at the first wheel during a braking process and / or during the implementation of a regulation for processing a wheel speed signal, and a first wheel speed sensor is not present at the first wheel or the first wheel speed sensor is present but does not provide a first wheel speed signal or does not provide an error-free first wheel speed signal, wherein the method comprises at least the following steps:

[0009] a) determining, measuring or estimating a second brake pressure of a second brake actuator for at least one second wheel, the brake device comprising the second brake actuator, during a braking process and / or during the implementation of the regulation, the second wheel being assigned a second wheel speed sensor which supplies, for example, error-free wheel speed signals, and

[0010] b) Determining or estimating the first brake pressure as a function of the second brake pressure.

[0011] In an expanded manner, in particular, the method can also include the step of controlling the output of a first brake pressure to the first brake actuator during a braking process and / or when implementing a regulation. Thus, in particular, the first brake pressure determined or estimated by means of the method is used to actuate the first brake actuator during a braking process and / or when implementing a regulation. In particular, the method can also include the step of identifying a failure of the first wheel speed signal or an error in the first wheel speed signal and / or identifying a first position of a first wheel on the vehicle that is associated with the first wheel speed sensor. The brake device, which will be described later, can also be constructed accordingly.

[0012] The detection of a failure or an error in the first wheel speed signal of the first wheel speed sensor can be realized, for example, by a plausibility check, which is performed in particular by comparison with a wheel speed signal provided by another wheel speed sensor. Therefore, the failure or error of the first wheel speed signal includes the implausible first wheel speed signal. In particular, the determination, measurement or estimation of the second brake pressure for the second brake actuator is performed at the second wheel which is not affected by the failure or error of the first wheel speed signal.

[0013] In particular, the method may further comprise the step of checking whether the second wheel speed signal is error-free, wherein if error-free, the second wheel speed signal is used for determining, estimating or calculating the second brake pressure, and otherwise, the second wheel speed signal is not used for determining, estimating or calculating the second brake pressure.

[0014] Furthermore, the present invention takes into account the case in which no wheel speed sensor is arranged at all on at least one first wheel, so that the first wheel speed sensor is missing there. This is because in such a case too, no first wheel speed signal can be provided. The absence of a first wheel speed sensor can be present in particular at all wheels of an axle whose wheel speed is then generally not sensed.

[0015] In other words, in both cases, namely in the case where a first wheel speed sensor is generally not provided on the at least one first wheel and in the case where a wheel speed sensor is present on the at least one first wheel but the wheel speed sensor does not provide a wheel speed signal or provides an erroneous wheel speed signal, the following result occurs, namely that the first wheel rotation signal for the at least one first wheel cannot be used to perform regulation and / or for a braking process.

[0016] In both cases, the invention provides an alternative strategy in order to still enable (wheel-individual) regulation at wheels that are not rotational speed-sensed or cannot be rotational speed-sensed, which regulation requires a wheel rotational speed signal as an input signal, such as an ABS regulation.

[0017] One embodiment of the present invention recognizes that knowing the position of a first wheel on the vehicle can be advantageous in order to identify at least one suitable second wheel on the vehicle (or its position on the vehicle), whose second brake pressure can then be used as a basis for determining or estimating the first brake pressure.

[0018] In the simplest case, a second brake pressure of a second brake actuator for at least one second brake actuator or a time profile of the second brake pressure is “copied” essentially identically in order to be used as a substitute for the first brake pressure of a first brake actuator for at least one first wheel. Otherwise, the second brake pressure can also be varied in order to be used as a substitute for the first brake pressure. Thus, the invention compensates for a failure of at least one wheel speed signal so that control can be carried out without significant loss of control quality.

[0019] However, the method and the braking device according to the invention, which will be described below, avoid using a second wheel speed signal of a second wheel speed sensor that is functioning properly or not affected by a failure as a substitute signal for a failed first wheel speed signal and then determining or estimating the first brake pressure based on the second wheel speed signal. The reason for this is that the transfer of the second wheel speed of the second wheel to the first wheel on the same axle or another axle would result in an unsatisfactory control quality.

[0020] In particular, the control can include a vehicle dynamics control system (ESP) and / or a brake slip control system (ABS) and / or a drive slip control system (ASR), which has subordinate brake slip control functions and / or drive slip control functions and / or rollover protection functions.

[0021] In the method, a selection may also be made among the wheels of the vehicle in order to identify at least one second wheel suitable for determining or estimating the first brake pressure of the first brake actuator for the at least one first wheel.

[0022] According to one development, in the method a wheel which is arranged on the same axle as the first wheel can be used as the second wheel.

[0023] Alternatively, in the method, a wheel arranged on another axle relative to the axle on which at least one first wheel is arranged can be used as the second wheel. Here, a wheel arranged on the same vehicle side or on another vehicle side relative to the vehicle side of at least one first wheel can be used as the second wheel.

[0024] In the method, a friction coefficient difference detection can also be carried out during the braking process and / or when carrying out the control in order to detect a friction coefficient difference situation.

[0025] Particularly preferably, in the method, a determination or estimation of the first brake pressure for the at least one first wheel is also carried out during the braking process as a function of the detected friction coefficient difference situation.

[0026] For example, in the method, a wheel arranged on the same axle as the at least one first wheel is used as the second wheel and a determination or estimation of a first brake pressure of a first brake actuator for the at least one first wheel is also performed based on the identified friction coefficient difference condition.

[0027] Particularly preferably, in the method, a determination or estimation of an axle load of an axle and / or an axle load distribution of an axle is also performed. A determination or estimation of a first brake pressure for at least one first wheel can then also be performed as a function of the determined or estimated axle load or as a function of the determined or estimated axle load distribution.

[0028] In particular, in the method, a wheel which is arranged on another axle relative to an axle on which at least one first wheel is arranged but on the same vehicle side as the at least one first wheel is used as a second wheel, and a determination or estimation of a first brake pressure of a first brake actuator for the at least one first wheel is also performed based on a determined or estimated axle load or based on a determined or estimated axle load distribution.

[0029] According to another aspect, the invention also comprises a computer program with a program code for carrying out the method according to the above when the computer program is executed on a processor device.

[0030] In another aspect of the invention, a controller or a controller system is also proposed, which has a processor device and a memory, which contains the computer program. The controller or the controller system can be a component of a braking device of a vehicle described below.

[0031] In another aspect of the invention, a pressure medium-actuated brake device of a vehicle is proposed, the brake device being provided with at least one regulating device which receives and processes wheel speed signals of wheel speed sensors as input signals, wherein a brake actuator of the brake device is respectively assigned to the wheels of the vehicle and a wheel speed sensor of the brake device is respectively assigned to at least some of the wheels of the vehicle, the wheel speed sensor generating a wheel speed signal corresponding to the wheel speed, and wherein the brake device is designed to:

[0032] a) determining or estimating a first brake pressure of a first brake actuator for at least one first wheel, the brake device comprising the first brake actuator, at which a brake pressure build-up is required during a braking process and / or during the implementation of a regulation for processing a wheel speed signal, and at which a first wheel speed sensor is not present or is present but does not provide a first wheel speed signal or does not provide an error-free first wheel speed signal, and

[0033] b) determining, measuring or estimating a second brake pressure of a second brake actuator for at least one second wheel, the braking device comprising the second brake actuator, during a braking process and / or during the implementation of the regulation, the second wheel being assigned a second wheel speed sensor which supplies, for example, error-free wheel speed signals, and

[0034] c) Determining or estimating the first brake pressure as a function of the second brake pressure.

[0035] Furthermore, the pressure-medium-actuated brake device may preferably be designed to generate a first brake pressure and to control the input of the first brake pressure into a first brake actuator of at least one first wheel.

[0036] In particular, the control can include a vehicle dynamics control system (ESP) and / or a brake slip control system (ABS) and / or a drive slip control system (ASR), which has subordinate brake slip control functions and / or drive slip control functions and / or rollover protection functions.

[0037] Furthermore, the brake device may be designed to select among the wheels of the vehicle in order to identify at least one second wheel suitable for determining or estimating the first brake pressure of the first brake actuator for the at least one first wheel.

[0038] The second wheel may also be a wheel arranged on the same axle as the first wheel.

[0039] Alternatively, the second wheel can be a wheel arranged on another axle relative to the axle on which at least one first wheel is arranged. Here, the second wheel can especially be a wheel arranged on the same vehicle side or on another vehicle side relative to the vehicle side of at least one first wheel.

[0040] According to an extension, the brake device can be configured to perform friction coefficient difference identification during the braking process for identifying a friction coefficient difference situation. In particular, the brake device can be configured to perform a determination or estimation of the first brake pressure during the braking process also as a function of the identified friction coefficient difference situation.

[0041] The second wheel may be a wheel which is arranged on the same axle as the at least one first wheel, and the brake device may be designed to also determine or estimate the first brake pressure as a function of the detected friction coefficient difference situation.

[0042] Particularly preferably, the braking device is designed to carry out a determination or estimation of the axle load of the axle and / or the axle load distribution of the axle.

[0043] In this case, the brake device may be designed to also determine or estimate a first brake pressure for at least one first wheel as a function of a determined or estimated axle load or as a function of a determined or estimated axle load distribution.

[0044] In particular, the second wheel can then be a wheel which is arranged on another axle relative to the axle on which the at least one first wheel is arranged, but on the same vehicle side as the at least one first wheel, and the braking device can be constructed to perform a determination or estimation of the first brake pressure also as a function of a determined or estimated axle load or as a function of a determined or estimated axle load distribution.

[0045] In the brake device, the regulation can be implemented in at least one electronic controller or an electronic controller system. For example, a primary electronic controller and a secondary electronic controller can be provided, wherein the regulation is implemented in the primary controller and / or in the secondary controller. In an expanded manner, at least some of the wheel speed sensors, preferably all of the wheel speed sensors, can be connected to the primary controller and / or to the secondary controller in order to transmit wheel speed signals.

[0046] Particularly preferably, the brake device is an electropneumatic brake device with brake pressure regulation. Such a brake device is also referred to as an electronically controlled brake system (EBS). Preferably, a pneumatic service brake cylinder is used as the brake actuator. However, the present invention is not limited to electropneumatic brake devices. The present invention can also be implemented in any type of brake device that is operated by a pressure medium and is electric, such as an electrohydraulic brake device.

[0047] Thus, for example, a friction coefficient difference detection can be performed on one axle of the vehicle, in which wheel speed sensors on both sides of the axle provide wheel speed signals. Now, in addition to a second brake pressure of a second brake actuator for at least one second wheel arranged on the same axle as the at least one first wheel, information about the detected friction coefficient difference situation is taken into account or used for determining, calculating or estimating a first brake pressure of a first brake actuator for at least one first wheel, whose first wheel speed sensor does not provide a wheel speed signal.

[0048] One embodiment of the method or of the braking device takes into account in particular a braking process in which a braking intervention is carried out on all wheels of the vehicle in order to brake the vehicle. In this braking process, the control can be active, which does not include a stability intervention, but includes, for example, a brake slip control intervention (ABS) and / or a rollover protection intervention.

[0049] In this case, the first brake pressure of a first brake actuator for at least one first wheel, whose first wheel speed sensor does not provide a wheel speed signal, can be determined, calculated or estimated based on the second brake pressure of a second brake actuator for at least one second wheel on the same vehicle side but on another axle (with a wheel speed sensor that is functioning properly or provides a wheel speed signal), thereby, for example, taking into account friction coefficient differences. In addition, the first brake pressure of the first brake actuator for at least one first wheel can be determined, calculated or estimated based on the axle load ratio between the axle with the at least one first wheel and the other axle with the at least one second wheel. In this case, the axle loads of one axle and of the other axle can be measured or estimated.

[0050] Optionally, when a bend is detected, the contact force shift toward the outside of the bend can also be taken into account and, depending on whether the defective wheel speed sensor is located on the inside or outside of the bend, the brake pressure can be relatively increased on the outside of the bend or reduced on the inside of the bend.

[0051] The method and the brake device also include an embodiment in which, for the first wheels on an axle, although two pressure regulating channels for wheel-individual regulation of wheel brake pressures may optionally be provided, no wheel speed sensor is arranged or provided on any of the first wheels of the axle. Then, since no wheel speed signal is available for all first wheels on the axle, the axle load ratio and / or the axle loads of the two axles relative to at least one other axle are preferably measured or estimated. Then, the (common) first brake pressure of the first brake actuator for the first wheels of the one axle can be determined, estimated or calculated, for example, based on the second brake pressure on the same side of the second brake actuator for the second wheel on the other axle and based on the axle load ratio or based on the axle load.

[0052] For example, the method and the braking device also include an embodiment in which only a stability intervention is performed by the vehicle dynamics control system (ESP), for example in order to react to an impending oversteering or understeering of the vehicle, without, for example, performing a braking intervention on all wheels of the vehicle in order to brake the vehicle.

[0053] In this case, the vehicle dynamics control (ESP) calculates the desired value for the brake pressure of certain wheels of the vehicle and the maximum permissible slip for these wheels from the rotation rate control deviation. If at least one of the wheels is a first wheel on an axle whose wheel speed sensor does not provide a wheel speed signal, then no slip control can be performed on this at least one first wheel. In this case, for example, a friction coefficient difference detection cannot be performed on another axle whose wheel provides a valid wheel speed signal, because, for example, not all wheels are braked on this other axle during the ESP intervention, and it is also not necessary to perform a friction coefficient difference detection on the other axle, because individual wheel braking is the control target in this case.

[0054] In this embodiment, if, for example, an ESP intervention is performed on the rear axle to prevent understeering of the vehicle, for example, a higher brake pressure is controlled in the brake actuator of the wheel on the inside of the curve of the rear axle than in the brake actuator of the wheel on the outside of the curve of the rear axle. If the wheel speed sensor of the wheel on the outside of the curve does not provide or cannot provide a wheel speed signal, the brake pressure is set on the wheel on the inside of the curve according to the relevant slip set value for the wheel on the inside of the curve. A brake pressure that is lower than the brake pressure of the wheel on the inside of the curve is then set on the wheel on the outside of the curve. If the wheel speed sensor of the wheel on the inside of the curve does not provide a wheel speed signal, the brake pressure is set on the wheel on the outside of the curve according to, for example, a reduced slip set value. A higher brake pressure is set on the wheel on the inside of the curve than on the wheel on the outside of the curve.

[0055] In this embodiment, if, for example, an ESP intervention is performed on the front axle to prevent oversteering of the vehicle, a high slip and a reduction in the lateral guiding forces are the objectives of the control strategy. If the relevant wheel speed sensor does not provide a wheel speed signal at the wheel to be controlled, the slip cannot be limited. Excessive slip can lead to locking of this wheel, which is in accordance with the control strategy in this case, but then the tire wear increases. In order to reduce the tire wear, the brake pressure can be reduced at the affected wheel, so that the brake locking of this wheel is also reduced as a result.

[0056] For example, the method and the braking device also include embodiments in which, during a braking process, a braking intervention is carried out at all wheels of the vehicle in order to brake the vehicle and (simultaneously) a stability intervention is carried out by means of vehicle dynamics control (ESP).

[0057] If, for example, an impending understeering of the vehicle is to be prevented by a brake intervention on the rear axle and the first wheel speed sensor of the first wheel on the rear axle is not able to provide a wheel speed signal, a friction coefficient difference detection is preferably performed, for example, on the front axle and a friction coefficient difference situation is detected thereby. A first brake pressure for the first brake actuator on the rear axle is then determined or estimated based on the detected friction coefficient difference situation on the front axle.

[0058] According to another specific embodiment, the contact forces of all wheels can also be estimated or ascertained, for example by axle load measurement of a sprung air suspension, which then supplies the axle loads to an electronic control unit (for example a brake control unit) for further processing, for example via a CAN data bus. A model integrated in the control unit can then ascertain the dynamic axle load shifts during the braking process and / or during the intervention control (for example by means of a detected lateral acceleration of the vehicle, a detected yaw angle or a detected yaw rate), so that the effects of the dynamic axle load shifts during the braking process and / or during the intervention control can also be taken into account when ascertaining the first brake pressure.

[0059] Therefore, preferably, a first brake pressure of a first brake actuator for at least one first wheel, at which brake pressure needs to be built up during the braking process and / or during the implementation of the regulation, is estimated or determined also as a function of dynamic axle load shifts occurring during the braking process and / or during the implementation of the regulation.

[0060] According to a further development of this embodiment, the friction coefficient between the wheels of the axle and the roadway can be estimated during braking using all wheel speed sensors that provide correct wheel speed signals. A first brake pressure is then calculated for a first wheel that does not have a wheel speed signal or has a faulty wheel speed signal, also based on the estimated wheel contact force of the first wheel and the friction coefficient of the wheel on the same vehicle side that provides correct wheel speed signals.

[0061] In addition, when determining the first brake pressure p1 , it can also be taken into account that when driving around a bend, the wheels on the outside of the bend rotate faster (for example by means of a measured rotation rate).

[0062] According to another embodiment, the vehicle can have an additional rear axle, but no wheel speed sensor is installed on the additional rear axle, but each wheel of the additional rear axle has its own pressure control channel in the brake device. This can be, for example, a commercial vehicle in which the front axle is a steering axle and each wheel has its own wheel speed sensor and its own brake pressure control channel. For example, the first rear axle has a wheel speed sensor and its own brake pressure control channel and an axle load sensor for each wheel, which detects the axle load of the first rear axle. Since, for example, in the case of ABS control, the brake pressure of the wheels of the second rear axle cannot be adapted as a function of the wheel speed, since there is no wheel speed information there, these brake pressures are "first brake pressures" in the sense of the term used so far.

[0063] In this case, the first brake pressure p1R on the right wheel of the second rear axle whose speed is not sensed can be determined, for example, based on the second brake pressure p2R of the right wheel on the same side of the first rear axle and based on the axle load ratio between the first and second rear axles. Similarly, the first brake pressure p1L on the left wheel of the second rear axle whose speed is not sensed can be determined, for example, based on the second brake pressure p2L of the left wheel on the same side of the first rear axle and based on the axle load ratio between the first and second rear axles.

[0064] Advantageous expansion schemes of the present invention are derived from the claims, the specification and the drawings. The advantages of the features and the combination of multiple features mentioned in the opening part of this specification are only exemplary and can act alternatively or cumulatively without necessarily being achieved by the embodiments according to the present invention. Other features can be known from the drawings, especially from the shown geometries and the relative sizes of multiple components relative to each other and their relative arrangement and functional connection. The combination of features of different embodiments of the present invention or the combination of features of different claims may also deviate from the selected reference relationship of the claims and be inspired by this. This also involves the following features: the features are shown in separate drawings or mentioned in the description of these drawings. These features can also be combined with features of different claims. Features for other embodiments of the present invention listed in the claims can also be omitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Below, an embodiment of the present invention is shown in the drawings and explained in more detail in the following description. In the drawings:

[0066] Figure 1 A schematic circuit diagram of a preferred embodiment of an electropneumatic service brake device as a preferred embodiment of the present invention is shown, wherein a pneumatic connection is shown there;

[0067] Figure 2 Show Figure 1 A schematic circuit diagram of a service brake device of , wherein electrical connections and partially pneumatic connections are shown there;

[0068] Figure 3 Show Figure 1 and Figure 2 A schematic cross-sectional view of a service brake valve device of an electro-pneumatic service brake device according to a preferred embodiment of the present invention in a "driving" position;

[0069] Figure 4 Shown implemented in Figure 1 and Figure 2 A schematic diagram of a functional unit of ABS regulation implemented in an electronic pneumatic service brake device;

[0070] Figure 5 Show with the help of Figure 1 and Figure 2 A schematic diagram of a brake pressure variation curve over time of a braking process performed by an electronic pneumatic service brake device;

[0071] Figure 6 A flow chart of a method for an electropneumatic service brake device according to a preferred specific embodiment is shown. DETAILED DESCRIPTION

[0072] Figure 1 A schematic circuit diagram of an electropneumatic service brake device 80 is shown as a preferred embodiment of the brake device according to the invention, wherein the pneumatic connections are shown there, and Figure 2 Show Figure 1 Schematic circuit diagram of an electropneumatic service brake device 80 , wherein electrical connections and partially pneumatic connections are shown there. The following description of the electropneumatic service brake device 80 relates to two figures.

[0073] A first axle 2A, for example a front axle VA, and a second axle 2B, for example a rear axle HA, are shown. The first axle 2A has a first wheel 1A and a second wheel 2B, each arranged on different vehicle sides, and the second axle 2B has a third wheel 1C and a fourth wheel 2D, each arranged on different vehicle sides. Wheels 1A, 1B, 1C and 1D are each assigned a pneumatic wheel brake actuator 4, which is designed as a pneumatic service brake cylinder in the example shown. Such a pneumatic wheel brake actuator 4 is arranged on each wheel 1 and, in this case, actuates a disk brake 3, for example, in order to generate a braking force.

[0074] To carry out a service braking process, the pneumatic wheel brake actuator 4 is loaded with a brake pressure p VA or p HA , whereby friction occurs in the disc brake 3, which results in a braking torque. In addition, a brake disc brake 3 is provided on the wheels 1A-1D. Figure 2 The wheel speed sensors shown in the figure, i.e., a first wheel speed sensor 5A is provided on the first wheel 1A, a second wheel speed sensor 5B is provided on the second wheel 1B, a third wheel speed sensor 5C is provided on the third wheel 1C, and a fourth wheel speed sensor 5D is provided on the fourth wheel 1D, so as to detect the wheel speeds of the four wheels 1A-1D and process the wheel speeds in more advanced functions (such as ABS, ASR and / or ESP).

[0075] In this illustration, for the sake of clarity, illustrations of other components of the vehicle and in particular illustrations of axle structures or brake structures are omitted. In addition, brake structures and vehicle structures of this type should not be regarded as limitations on the subject matter of the present invention. Brake structures and vehicle structures of this type are used only as examples to illustrate the mode of action of the subject matter according to the present invention. More precisely, alternative structural possibilities of the electronic pneumatic service brake device can also be considered, for example, instead of the disc brake 3 shown, a drum brake can be considered. Other embodiments of the vehicle can also be considered. Therefore, for example, more than one front axle or rear axle VA, HA can be provided, that is, more than two axles can be provided as a whole.

[0076] Next, an electropneumatic service brake device 80 will now be described which has a compressed air reservoir 10 which supplies compressed air to various components 18 , 20 , 24 , 82 of the electropneumatic service brake device 80 via supply lines 14 , 14 a , 14 b , 14 c .

[0077] Here, a component is Figure 3 1 , the schematically illustrated electropneumatic service brake valve device 18 is in the form of a foot brake module, for example, which is connected to the supply line 14 via a supply input 15. Compressed air is thus supplied to the service brake valve device 18. In addition, the service brake valve device 18 has a pneumatic control input 19, via which the service brake valve device can receive a pneumatic control pressure p St The service brake valve device 18 is then pneumatically controlled by means of the pneumatic control pressure. In addition, the service brake valve device 18 has two pneumatic control outputs 16, 17, via which the service brake valve device can control the first pneumatic brake control pressure p 1 and / or the second pneumatic brake control pressure p 2 The control outputs are into the pneumatic control lines 22 , 23 .

[0078] Furthermore, the service brake valve device 18 has a service brake actuation mechanism 94, such as a brake pedal, via which a driver's braking request can be input. Figure 3 The brake value transmitter 86 shown in FIG. 8 , which is particularly electrical and works in a contactless manner, detects the driver's braking request in the electrical channel of the service brake valve device and controls the input of the braking request as an actuation-dependent electrical actuation signal BS into the primary control connection SV1, as shown in FIG. Figure 2As shown. The electric actuation signal BS is then controlled via the primary control connection SV1 into the primary electronic brake control device 40, which is formed here, for example, by an electronic EBS controller. The primary electronic brake control device 40 then generates a first electric brake request signal S1 as a function of the actuation signal BS, in which higher-level functions, such as the braking force distribution in relation to the axle load, are also taken into account. In this respect, the first electric brake request signal S1 can also be different for the front axle VA and the rear axle HA or be formed in an axle-dependent manner.

[0079] The service brake valve device 18 has a housing in which a tappet piston 91 is received in an axially movable manner, and the tappet piston has a tappet receiving portion 92 that protrudes through a cover opening of the housing cover. A tappet, not shown here, protrudes from above into the tappet receiving portion 92, and the tappet is connected to a service brake operating mechanism 94, which is in the form of a foot brake plate, for example. Therefore, when the driver operates the service brake operating mechanism 94, the tappet is pressed into the tappet receiving portion 92 and the tappet piston 91 is moved by the operating force. Figure 3 The tappet piston 91 preferably transmits the actuating force via a tappet piston compression spring 102 to the control piston 12 , which is likewise supported in the housing 2 in an axially movable manner.

[0080] Furthermore, the control piston 85 is mechanically operatively connected to the tappet piston 91 via a tappet piston rod 87, wherein when the tappet piston rod 87 has reached the bottom of the sleeve 103, for example when the tappet piston 91 is moved toward the control piston 85 due to an actuation of the service brake actuation mechanism 94, the tappet piston rod 87 is connected to the tappet piston 91 and can be axially stopped in the end of the control piston 85 that is configured as a cup-shaped sleeve 103. On the other hand, when the tappet piston 91 moves away from the control piston 85, the tappet piston rod 87 can slide in the sleeve 103.

[0081] On the other side of the control piston 85, an outlet seat of a double-seat valve 88 is formed on the piston rod of the control piston 85, which outlet seat seals against or lifts off the cup-shaped and hollow valve body of the double-seat valve 88, which is supported in the housing so that it can move in the axial direction, and which outlet seat releases the flow cross section between the working chamber 98 and the head-side through-opening in the valve body, which leads to the exhaust port 99. The working chamber 98 is connected to the control outputs 16, 17, and these are connected to the control lines 22, 23, which in turn are connected to the pneumatic control inputs 95, 96 of the pressure regulating module 20. In simplified form, the control outputs 16, 17 are arranged in one connection in the drawing, but in reality there are two separate control outputs 16, 17.

[0082] In the service brake valve device 18, a control chamber 90 is formed between a tappet piston 91 and a surface of the control piston 85 that faces the tappet piston. In this case, the pneumatic control inlet 19 opens into the control chamber 90 at the housing.

[0083] The control line 13 and thus the control output 84 of the solenoid valve device 82 are also connected to the pneumatic control input 19, and the solenoid valve device is connected at its supply input 83 to a supply line 14a connected to the compressed air reservoir 10. In addition, a supply input 15 is also present on the housing of the service brake valve device 18, to which the supply line 14 is connected and which is connected to the reservoir chamber 89 of the service brake valve device 18.

[0084] The valve body is pressed against the inlet seat of the double seat valve 88 by means of a valve body compression spring, which is supported on the bottom of the housing and on the inside of the valve body, and the inlet seat is formed on the radial inner edge of the central through hole of the other inner wall of the housing. In the state in which the valve body is lifted from the inlet seat against the action of the valve body compression spring, the flow cross section between the supply inlet 15 or the reserve chamber 89 and the working chamber 98 is released, which allows compressed air at the reserve pressure to flow into the control outputs 16, 17, i.e. into the control lines 22, 23, in order to charge the wheel brake actuators 4 of the axle concerned or the brake circuit concerned (front axle brake circuit and rear axle brake circuit).

[0085] exist Figure 3 , the “driving” position of the service brake valve device 18 is shown, in which the outlet seat is lifted from the valve body and the control outputs 16, 17 and therefore also the wheel brake actuator 4 connected thereto are connected to the exhaust port 99. The active pneumatic wheel brake actuator 4 is thereby released.

[0086] according to Figure 1 and Figure 2The pressure regulating module 20 is known, for example, from "Kraftfahrtechnisches Taschenbuch", 24th edition, April 2002, Robert Bosch GmbH, page 763, in particular Figure E. In this case, for example, each channel of the two-channel pressure regulating module 20 (here, for example, the front axle channel and the rear axle channel) contains an electromagnetic backup valve, which is controlled by the primary electronic brake control device 40, wherein each backup valve is connected to the pneumatic control input 95, 96. On the output side, the backup valve is connected to the pneumatic control input of the integrated relay valve. Such a backup valve is switched to its blocked position in the state in which it is energized by the primary electronic brake control device 40, that is, in the case of an intact electric service brake circuit, and the pneumatic brake control pressure present at the backup valve is thereby suppressed. In the energized state, the backup valve switches into its passage position, whereby the pneumatic brake pressure can act on the relay valve, which then, based on the reserve pressure controlled from the compressed air reservoir 10 into the pressure regulating module 20, increases the pneumatic brake pressure in a quantitatively enhanced manner and then acts as the front axle brake pressure p VA and rear axle brake pressure p HA At the pressure output of the pressure regulating module 20, a control output is given into lines 26, 27 which are connected to the wheel brake actuator 4 via a pressure control valve 28. Preferably, the pressure control valve 28 is connected to a primary control connection SV1 and a secondary control connection SV2.

[0087] In addition, the pressure regulating module 20 comprises an inlet-outlet-solenoid valve combination, which is controlled by an integrated electronic pressure regulating module controller and which is connected on the output side to the pneumatic control input of the relay valve. The relay valve can therefore be loaded either by a pneumatic brake control pressure which is controlled through a non-energized standby valve control or by a pneumatic brake control pressure which is generated electrically by controlling the inlet-outlet-solenoid valve combination with the aid of the integrated electronic pressure regulating module controller. The pressure regulating module controller is connected via an electrical control input 97 to the primary control connection SV1, to which the primary electronic brake control device 40 is also connected, whereby the pressure regulating module controller can be controlled by the primary electronic brake control device 40 or can be supplied with a control signal.

[0088] In addition, a pressure sensor is integrated into such a pressure control module 20 for measuring the actual brake pressure p VA or p HAThe actual brake pressure measured by the pressure sensor is then compared in the sense of pressure regulation with a desired brake pressure, which is represented by a first electric brake request signal S1, which is input into the primary control connection SV1 controlled by the primary electronic brake control 40. For this purpose, the electronic pressure regulation module controller of the pressure regulation module 20 includes a corresponding pressure regulation routine.

[0089] The solenoid valve device 82 can realize the filling or exhaust of the control chamber 90 in an electronically controlled manner and is electrically controlled by the secondary electronic brake control device 41. For this purpose, the solenoid valve device 82 is connected to the secondary control connection SV2 via an electrical control input, which is formed here, for example, by a second CAN data bus.

[0090] In particular, the primary electronic brake control device 40, the electrical / electronic part of the pressure regulating module 20 and the brake value transmitter 86 of the service brake valve device 18 are connected to the primary control connection part SV1, which is independent of the secondary control connection part and is unrelated to the secondary control connection part SV2, and the secondary electronic brake control device 41 and the solenoid valve device 82 are connected to the secondary control connection part.

[0091] In particular, a data connection 101 may be provided between the primary electronic brake control device 40 and the secondary electronic brake control device 41, in particular for data exchange and signal exchange and / or for the purpose of mutual monitoring. In particular, the actuation signal BS and / or the first electric brake request signal S1 may also be controlled to be input into the secondary electronic brake control device 41 and / or the second electric brake request signal S2 may be controlled to be input into the primary electronic brake control device 40 via the data connection 101. For this purpose, the integrity of the primary electronic brake control device 40 and the secondary electronic brake control device 41 is not necessary, since the signals are preferably only circulated.

[0092] Preferably, except in Figure 3 In addition to the exhaust port 100 shown in FIG. 1 , the solenoid valve device 82 also has at least one pressure sensor (not shown here) for measuring the pneumatic control pressure p at the control output 84. ST , so that in combination with a corresponding algorithm in the secondary electronic brake control device 41 to which the actual value is reported, a control pressure p of the control output can be realized or preferably also executed. ST The secondary electronic brake control device 41 controls the solenoid valve device 82 via the secondary control connection SV2 by means of the second electric brake request signal S2, wherein the solenoid valve device 82 then generates a pneumatic control pressure p at the control output 84 according to the second electric brake request signal S2. ST .

[0093] For example, in the solenoid valve device 82, an electro-pneumatic proportional valve can ensure that the output control pressure p is controlled at the control output terminal 84 (proportionally) according to the second electric brake request signal S2. St , wherein charging and exhausting can also be performed. In another embodiment not shown here, an inlet / outlet valve combination consisting of, for example, two 2 / 2-way solenoid valves can be provided, wherein the inlet valve connected to the supply input 83 is closed when not energized and opens when energized, while the outlet valve is opened when not energized and closed when energized. According to another embodiment, a 2 / 3-way solenoid valve as a charging and exhausting valve having a charging position and an exhausting position can also be used as the solenoid valve device 82 in combination with a 2 / 2-way solenoid valve as a holding valve, which holds the pressure at the control output in its blocked position.

[0094] Such a solenoid valve device 82 can be used in particular in each of the above-described embodiments in combination with a pressure sensor and a control pressure regulator in order to regulate the pneumatic control pressure p present at the control output 84. St , the control pressure regulator is implemented in the secondary electronic brake control device 41 .

[0095] In addition, the electronic pneumatic service brake valve device 80 includes a driver assistance system 93, such as an automatic driving device or an emergency brake assistance device, which can automatically generate a braking request, and the braking request is then represented by an auxiliary braking request signal AS, which is here, for example, controlled to be input into the primary electronic brake control device 40 and the secondary electronic brake control device 41, such as Figure 2 As shown. Alternatively, the auxiliary brake request signal AS can also be controlled to be input only into the secondary electronic brake control device 41. With the help of the automatic driving device, at least partially autonomous driving can be achieved.

[0096] Routines for driver assistance system 93 may also be implemented in primary electronic brake control unit 40 and / or in secondary electronic brake control unit 41 .

[0097] In addition, the primary electronic brake control device 40 is supplied with electric energy by a primary supply source 52 , which is independent of a secondary supply source 58 , which supplies electric energy to the secondary electronic brake control device 41 .

[0098] In particular, the wheel speed signals of the first, second, third and fourth wheel speed sensors are controlled and inputted not only into the primary electronic brake control device 40 but also into the secondary electronic brake control device 41 via signal connections not shown here. Preferably, since the routines of the driving dynamics control ESP with the subordinate brake slip control function (ABS) and drive slip control function (ASR) and rollover protection function (ROP) are implemented not only in the primary electronic brake control device 40 but also in the secondary electronic brake control device 41, the two brake control devices 40 and 41 can control and regulate these functions separately.

[0099] In the following, a normal operating mode, a first redundancy level and a second redundancy level of the electropneumatic service brake device are now described.

[0100] Normal operation mode

[0101] Driver brake

[0102] When the driver actuates the service brake actuation mechanism 94 of the service brake valve device 18 (which corresponds to the driver's braking request), the degree of actuation of two redundant brake value transmitters 86 is measured in the intact main electric service brake circuit, which are preferably arranged axially one after another and preferably function in a contactless manner. The electric actuation signal BS detected by the brake value transmitter 86 is generated in the electric channel of the service brake valve device 18, the electric actuation signal is made compatible with the data bus, and the electric actuation signal is controlled to be input into the primary electronic brake control device 40 via the primary control connection PV1. Since higher-level functions, such as axle load-dependent braking force distribution, are implemented in the primary electronic brake control device 40, a first brake request signal S1 is generated there for the front axle VA and the rear axle HA based on the electric actuation signal BS and the first brake request signal is controlled to be input into the relevant channel of the pressure regulating module 20 and the trailer control module 24. There, a brake pressure p is then generated for the front axle VA via an integrated solenoid valve and a relay valve based on the corresponding brake request signal S1. VA and the brake pressure p for the rear axle HA HA , and controls the brake pressure for the front axle and the brake pressure for the rear axle via the pressure control valve 28, which is opened here, to be input into the wheel brake actuator 4 in order to implement the required service braking. Similarly, the trailer control module 24, which is also configured as a pressure regulating module, converts the first brake request signal S1 into a trailer brake pressure p 挂车 This trailer brake pressure is then fed in a controlled manner into a possibly coupled trailer via a coupling head “trailer” (not shown here).

[0103] In the secondary pneumatic brake circuit, for example, the brake pressure p for the front axle VA is used as the pneumatic control pressure. VA The trailer control module 24 is actuated pneumatically, but the pneumatic control pressure is suppressed by the energized and therefore closed integrated backup valve and is therefore not realized.

[0104] If excessive brake slip occurs in the event of braking requested by the driver, the primary electronic brake control device 40 controls the pressure control valve 28 (connected to the primary control connection SV1 and to the secondary control connection SV2) Figure 2 ), in which the ABS routine is preferably implemented in order to adjust the brake pressure wheel by wheel until the brake slip becomes permissible. The same naturally also applies to the wheel-individual control / regulation of the brake pressure within the framework of the driving dynamics control ESP.

[0105] In parallel, in the case of a driver's braking request, in the secondary pneumatic service brake circuit or in the two pneumatic channels of the service brake valve device 18, the tappet piston 91 moves downward, wherein the tappet piston 91 is pressed against the bottom of the cup sleeve 103 and the control piston 85 also moves downward until the outlet seat seals against the valve body and thus closes the connection between the control outputs 16, 17 for the pneumatic service brake circuit and the exhaust connection 99, so that no further exhaust of the associated wheel brake actuator 4 can take place. In the case of further actuation of the service brake actuation mechanism 94 according to the driver's braking request, the valve body is then pressed downward by the outlet seat resting on the valve body while being lifted from the inlet seat. As a result, compressed air at a reserve pressure passes from the reserve chamber 89 into the working chamber 98 and from there into the control outputs 16, 17 for the pneumatic service brake circuit or into the associated wheel brake actuator 4 in order to charge the wheel brake actuator and thus compress the wheel brake actuator. This is pure driver braking, wherein, due to the operating force applied by the driver to the service brake operating mechanism 94 according to the driver's braking request, a first operating force F1 is applied to the control piston 85 via the plunger piston compression spring 102, which ultimately adjusts the control piston to its inflated position.

[0106] In the case of such braking initiated purely by a driver braking request, the solenoid valve device 82 is controlled by means of the secondary electronic brake control device 41 to a vented state in which the control chamber 90 is connected to the atmosphere in order to avoid pressure effects that could occur due to expansion of the control chamber 90. The secondary electronic brake control device 41 receives instructions for this from the primary electronic brake control device 41, for example, via the data connection 101.

[0107] However, since the main electric service brake circuit is intact, the first and second brake control pressures p1 and p2 present at the control output terminals 16, 17 and controlled via control lines 22, 23 to be input into the pneumatic control input terminals 95, 96 of the pressure regulating module 20 are suppressed in the pressure regulating module 20 at the backup valve which is then energized and therefore closed, and are not transmitted to the integrated relay valve.

[0108] Therefore, with an intact primary electric service brake circuit, the secondary pneumatic service brake circuit is inoperative.

[0109] Automatic / autonomous braking

[0110] In the following, the following situation is now considered: in this situation, the driver does not apply a braking request and therefore does not operate the service brake operating mechanism 94, but the driver assistance system 93 controls the input of the auxiliary braking request signal AS not only to the primary electronic brake control device 40 but also to the secondary electronic brake control device 41, such as Figure 2 shown.

[0111] Here, the primary electronic brake control device 40 can generate a first electric brake request signal S1 based on the auxiliary brake request signal AS, and the first electric brake request signal is then converted into a corresponding brake pressure p in the electric service brake circuit through the pressure regulating module 20 and the trailer control module 24 in the manner described above. VA 、p HA and p 挂车 The auxiliary brake request signal AS is therefore then implemented via an intact electric service brake circuit or an intact pressure control module 20 .

[0112] In parallel or simultaneously therewith, the secondary electronic brake control device 41 generates a second electric brake request signal S2 based on the auxiliary brake request signal AS, which is input into the solenoid valve device 82 via the secondary control connection SV2, and the solenoid valve device is subsequently adjusted to the charging state and thereby generates a pneumatic control pressure p St , the control chamber 90 is loaded with the pneumatic control pressure. The control pressure p that prevails in the controller 90 is then St The reaction is to the push rod piston 91 which limits the control pressure, and therefore to the service brake operating mechanism 94, which the driver can feel at his foot (pedal reaction) when he touches the service brake operating mechanism 94. Therefore, the driver can feel the introduction of automatic braking at his foot.

[0113] Then, depending on the pneumatic control pressure p that is input into the control chamber 90, StDepending on the modulation of the control piston 85, it is possible to set a defined second actuation force F2 on the control piston 85. As described above in the case of the first actuation force F1, the second actuation force F2 ensures the generation of a first and a second pneumatic brake control pressure p1, p2, which are controlled to be input into the pressure regulating module 20 at the control outputs 16, 17 and via the control lines 22, 23, and which preferably act on the control piston 85 in parallel and in the same direction with respect to the first actuation force F1. However, there, the first and the second pneumatic brake control pressures p1, p2 are suppressed by the backup valve, which is energized by the primary electronic brake control device 40 and thus remains closed, and therefore (initially) have no effect. However, if the backup valve is de-energized due to a defect in the electric service brake circuit and is thus opened, the first and the second pneumatic brake control pressures p1, p2 can immediately act on the integrated relay valve in the pressure regulating module 20.

[0114] Combination of driver braking and autonomous / automatic braking

[0115] In addition, the following situation can also be considered: in this situation, for example, when the driver brakes due to an emergency braking situation, but the braking request of the driver assistance system is greater than the driver's braking request, braking should not only be carried out according to the driver's braking request, but also according to the automatically generated braking request. The driver assistance system is, for example, in the form of an emergency brake assistant or an automatic driving device.

[0116] Then, a brake pressure p is built up in the electric service brake circuit controlled by the primary electronic brake control device 40 mainly based on the auxiliary brake request signal AS. VA or p HA In other words, in the main electric service brake circuit, the driver's braking request is overridden by the braking request of the driver assistance system.

[0117] In parallel with this, on the one hand, a first actuation force F1 from the driver's braking request and a second actuation force F2 from the automatically generated braking request act in the same direction and in parallel on the control piston 85 of the service brake valve device 18, wherein the actuation forces F1, F2 are added at the control piston 85 and then the first pneumatic brake control pressure p1 and the second pneumatic brake control pressure p2 are controlled to be output via the control lines 22, 23 at the control output ends 16, 17 to the pneumatic control input ends 95, 96 of the pressure regulating module 20, but are suppressed there by the backup valve energized by the primary electronic brake control device 40.

[0118] First redundancy level

[0119] If a defect or a fault now occurs in the main electric service brake circuit, for example due to a defect or failure of the electrical / electronic parts of the primary supply source 52, the primary electronic brake control device 40 and / or the pressure regulating module 20, the two backup valves integrated in the pressure regulating module 20 are de-energized and thus switched to their open position, so that in the event of a braking request by the driver assistance system 93, i.e. after the generation of the second electric brake request signal S2, the first and second brake control pressures p1, p2 already present there can then control the integrated relay valve in question, so that a braking pressure p1 for the front axle VA can be generated. VA and the brake pressure p for the rear axle HA HA Since the brake pressure p for the front axle is VA is used as pneumatic control pressure for the trailer control module 24 and can also generate the trailer brake pressure p 挂车 , so that a possibly coupled trailer can also be braked.

[0120] In the first redundancy level, it is therefore assumed that the secondary electronic brake control device 40 is intact, since otherwise it would not be possible to generate the second electric brake request signal S2 and to form the first and second brake control pressures p1 and p2 accordingly.

[0121] For wheel-specific adaptation of the brake pressure p VA and p HA For example, within the framework of brake slip control ABS, drive slip control ASR and / or driving dynamics control ESP, the intact secondary electronic brake control device 41 can individually control the pressure control valve 28 via the secondary control connection SV2 (“pressure hold”, “pressure reduction”, “pressure increase”).

[0122] Therefore, in the first redundancy level, in the event of a failed electric service brake circuit, electrical redundancy is formed in the then active first and second pneumatic brake circuits by the first and second pneumatic brake control pressures p1 and p2, since the first and second pneumatic brake control pressures p1 and p2 are then generated electrically and automatically by means of the secondary electronic brake control device 40.

[0123] In addition, in the event of a failed electric service brake circuit, the first and second pneumatic brake control pressures p1 and p2 realize an automatic braking request in the first and second pneumatic brake circuits that are then also effective, wherein, in the event of a failed electric service brake circuit, the first and second pneumatic brake control pressures p1 and p2 can then immediately take effect because the first and second pneumatic brake control pressures have already been generated according to the auxiliary brake request signal AS and are then also already present at the backup valve of the pressure regulating module 20.

[0124] Second level of redundancy

[0125] If, starting from the state of the electro-pneumatic service brake device 18 in the first redundancy level, that is, if the primary electronic brake control device 40 fails, a defect or fault now also occurs in the control of the pneumatic service brake circuit by the secondary electronic brake control device 41 and the solenoid valve device 82, then the first and second pneumatic brake control pressures p1 and p2 can no longer be generated electrically, so that autonomous or automatic service braking can then no longer be performed by the driver assistance system 93.

[0126] The pneumatic service brake circuit can then only be controlled by the driver's braking request and the first and second pneumatic brake control pressures p1 and p2 that are then generated mechanically. Since the backup valve in the pressure regulating module 20 is then de-energized and thus switched into its passage position, the first and second pneumatic brake control pressures p1 and p2 result in a brake pressure p1 for the front axle in the pressure regulating module 20. VA and the brake pressure p for the rear axle HA HA Generation of the braking pressure p preferably for the front axle VA VA is used as pneumatic control pressure for the trailer control module 24 and can also generate the trailer brake pressure p 挂车 , so that a trailer which may be coupled to the vehicle can also be braked.

[0127] However, since all electric service brake circuits have failed, pressure regulation and actuation of the pressure control valve 28 are no longer possible, so that wheel-by-wheel individual regulation of the brake pressure p VA and p HA .

[0128] Therefore, as described above, the electro-pneumatic service brake device 80 and in particular the secondary electronic brake control device 41 (through corresponding programming), the solenoid valve device 82 and the service brake valve device 18 are constructed in such a way that the first and second pneumatic brake control pressures p1 and p2 are generated, for example, in accordance with each automatically generated auxiliary brake request signal AS, which represents an autonomous or automatic braking request, and are then immediately and directly present at the (still) closed solenoid standby valve of the pressure regulating module 20.

[0129] Therefore, regardless of whether the driver is currently requesting braking and / or automatic braking, the first pneumatic brake control pressure p1 and the second pneumatic brake control pressure p2 are always already present in the pressure regulating module 20 and can therefore immediately ensure the brake pressure p1 after a failure of the electric service brake circuit. VA 、p HA and p 挂车 The production of.

[0130] However, in order to reduce the wear on the solenoid valve device 82 and on the service brake valve device 18 (which, as mentioned above, are activated in practice in every case of an autonomous or automatic braking request) and in order to reduce the acoustic loads generated thereby, it is preferred that the auxiliary brake request signal AS is activated only when the magnitude of the automatic or autonomous braking request represented by the auxiliary brake request signal AS is greater than the limit brake request a. 极限 When the value of p is reached, the pneumatic control pressure p is generated electrically St and / or the first and second pneumatic brake control pressures p1 and p2 . This limitation can be achieved, for example, by corresponding programming of the secondary electronic brake control device 41 .

[0131] Therefore, preferably, the limit braking requirement a 极限 Is a deceleration that is not equal to zero or represents such, for example -3m / s 2 Therefore, if the required deceleration is -4m / s 2 If an automatic or autonomous braking request (deceleration) is made, the first and second pneumatic brake control pressures p1 and p2 are generated electrically. On the contrary, at only -2 m / s 2 In the event of an automatic or autonomous braking request (deceleration), the first and second pneumatic brake control pressures are not generated electrically.

[0132] However, alternatively, the limit braking requirement a 极限 It can also be equal to zero, wherein the first and second pneumatic brake control pressures p1 and p2 are then generated electrically in the event of any requested autonomous or automatic braking with a magnitude greater than zero.

[0133] The first and second pneumatic brake control pressures p1 and p2 can also be generated and input into the pneumatic control inputs 95 and 96 of the pressure regulating module 20 in a controlled manner according to at least the following variables:

[0134] a) The mass ratio between the towing vehicle and the trailer;

[0135] b) the axle loads of the rear axle HA and the front axle VA or the axle load ratio between the rear axle HA and the front axle VA,

[0136] c) The number of pneumatic channels of the service brake valve assembly.

[0137] Sensor redundancy

[0138] If, for example, the signal connection between the wheel speed sensors 5A-5D and the primary electronic brake control unit 40 and / or the secondary electronic brake control unit 41 is faulty or disturbed, for example, if a plug of the relevant wheel speed sensor 5A-5D connected to the signal line falls off or has a contact fault or the signal line itself has an interruption, problems may arise in the regulation, in particular the ABS regulation, which is preferably fully integrated into the primary electronic brake control unit 40 and the secondary electronic brake control unit 41, respectively.

[0139] exist Figure 4 , the functional units "signal processing", "ABS" and "brake pressure determination" are shown, which determine the individual brake pressures for wheel brake actuators 4 during a braking process assumed here within the framework of brake slip control (ABS). These functional units are implemented in program code and can be arranged either in a distributed manner or in Figure 1 and Figure 2 The service brake device 80 is distributed, for example, to the primary control device 40, the secondary control device and / or the electronic controller of the pressure regulating module 20, or is respectively completely integrated in only one of these control devices and respectively completely integrated in at least two of these control devices.

[0140] Then, Figure 4 The operation of the brake slip control (ABS) is shown in the case of a failure of the wheel speed signal, in particular due to one of the above-mentioned problems. Figure 4 In the example shown, it is assumed that the wheel rotation signal of the first wheel speed sensor 5A assigned to the first wheel 1A (e.g. the left front wheel) fails. Therefore, all other wheel speed sensors 5B, 5C and 5D can control the input of the corresponding wheel speed signals to the signal processing, which is integrated into the two control devices 40 and 41, respectively, while this is not the case for the first wheel speed signal of the first wheel speed sensor 5A, which is Figure 4 Indicated by a horizontal bar.

[0141] Then, although the functional unit "signal processing" can calculate the wheel speeds of the second, third and fourth wheels 1B, 1C and 1D and the vehicle speed from the wheel speed signal, it cannot calculate the wheel speed of the first wheel 1A. Figure 4 The functional unit “ABS” then calculates the individual desired brake pressures for the three wheels 1A-1C from the vehicle speed and the wheel speeds of the three wheels 1A, 2A and 3A, and then refers to Figure 1 and Figure 2In an embodiment of the service brake device 80 of FIG. 1 , these desired brake pressures are input as desired brake pressure signals into the pressure control module 20 in order, for example, to adjust these desired brake pressures to the brake actuators 4 in each case within the framework of brake pressure control. Since the actual brake pressure can be measured in the pressure control module 20 by means of an integrated pressure sensor, the actual brake pressure can be fed back to the "brake pressure determination" functional unit in order to implement brake pressure control. Thus, the actual brake pressures present in the wheel brake actuators 4 of the first, second and third wheels 1A, 1B and 1C and the corresponding desired brake pressures are known during ABS control.

[0142] In addition, the "brake pressure determination" functional unit receives information about the axle load of the first axle 2A (here: front axle VA) and the axle load of the second axle 2B (here: rear axle HA) from axle load sensors respectively installed there. Alternatively, without axle load sensing, values ​​for the axle loads or for the axle load ratios can also be estimated from other detected values.

[0143] Furthermore, the “brake pressure determination” functional unit can determine within the framework of friction coefficient difference detection from the wheel speed sensors 5C of the third wheel 1C and the wheel speed sensors 5D of the fourth wheel 1D on the second axle 2A whether a friction coefficient difference situation exists during the braking process, i.e. whether the road friction coefficient μL between the wheels 1A, 1C on the left side of the vehicle and the road is different from the road friction coefficient μR between the wheels 1B, 1D on the right side of the vehicle and the road. Because in the case of wheel-individual brake pressure determination within the framework of ABS control, in the case of significant differences in the road friction coefficients μR and μL, different brake pressures need to be set or adjusted for the wheels on the left side of the vehicle and on the right side of the vehicle, so that the vehicle does not rotate about its vertical axis during the braking process.

[0144] Preferably, in the functional unit "brake pressure determination", the first brake pressure of the sensor of the brake actuator 4 for the first wheel 1A, which initially could not be determined due to the lack of wheel speed information from the first wheel speed sensor, is determined in the following way: for example, the second brake pressure of the brake actuator 4 for the second wheel 1B arranged on the same first axle 2A as the first wheel 1A is used as the basis for the determination.

[0145] This can be achieved, for example, by using a second actual brake pressure measured internally, for example, in the pressure control module 20 or a second desired brake pressure of the brake actuator for the second wheel 1B calculated by the functional unit "ABS" or using a corresponding time profile. Alternatively, the first brake pressure p1 of the brake actuator 4 for the first wheel 1A can be determined not only as a function of the second actual / desired brake pressure p2, but also as a function of the measured or estimated axle loads of the first axle 2A and the second axle 2B and / or as a function of the roadway friction coefficients μR and μL on the right and left sides of the vehicle.

[0146] exist Figure 5 , the time profile of the second brake pressure p2 of the wheel brake actuator 4 for the second wheel 1B during the braking process formed by the functional unit “ABS” is shown on the left, and the first brake pressure p1 determined according to the above method for the wheel brake actuator 4 for the first wheel 1A is shown on the right. The time profile shown there marks an ABS control cycle, which is produced by the typical alternation of a brake pressure reduction and a brake pressure increase. Preferably, the first brake pressure p1 of the brake actuator 4 for the first wheel 1A is determined here not only on the basis of the second brake pressure p2, but also on the basis of the road friction coefficients μR and μL estimated from the wheel speed signals of the wheel speed sensors 5C and 5D of the wheels 1C and 1D on the second axle 2B (here: the rear axle HA) on the right and left sides of the vehicle.

[0147] If there is no significant difference between the roadway friction coefficients μR and μL on the right and left sides of the vehicle, the average time profile for the first brake pressure, which is drawn in a solid line, is determined. In this case, the time profile of the second brake pressure p2 is essentially "copied" in order to simulate the time profile of the first brake pressure p1, which is unknown due to the lack of wheel speed information.

[0148] If the friction coefficient difference detection indicates that a friction coefficient difference situation exists during the braking process, and it is detected that the roadway friction coefficient μR between the wheels 1B, 1D on the right side of the vehicle and the roadway is significantly greater than the roadway friction coefficient μL between the wheels 1A, 1C on the left side of the vehicle and the roadway, then the first brake pressure p1 is determined to be Figure 5 The time profile shown on the right in dashed lines in FIG. 1 is greater than the time profile of the second brake pressure p2 in terms of average value. In other words, the "copied" time profile of the second brake pressure p2 is then increased by an offset Δp in order to prevent the vehicle from rotating about the vehicle height axis during the ABS-controlled braking process.

[0149] Otherwise, if the friction coefficient difference detection indicates that a friction coefficient difference situation exists during the braking process, and it is detected that the road friction coefficient μL between the wheels 1A, 1C on the left side of the vehicle and the road is significantly greater than the road friction coefficient μR between the wheels 1B, 1D on the right side of the vehicle and the road, then the first brake pressure p1 is determined to be 1 / 200 Nm. Figure 5 The time profile drawn in dashed lines on the right in FIG. 1 is smaller than the time profile of the second brake pressure p2 in terms of average value. In other words, the “copied” time profile of the second brake pressure p2 is then reduced by an offset Δp.

[0150] Since the second brake pressure p2 is the brake pressure regulated by the ABS control, the first wheel 1A is then braked by the method described above also with the "copied", regulated first brake pressure p1. The actually unknown time profile of the first brake pressure is then substantially simulated by the time profile of the second brake pressure p2 generated by the ABS control. Optionally or as required, this simulated time profile of the first brake pressure p1 can be adapted according to the identified friction coefficient difference conditions and / or according to the measured or estimated axle load.

[0151] Below, refer to Figure 6 Flowchart 200 of FIG. 5 illustrates how the program code of the method reacts to a failure of the wheel speed signal of first wheel speed sensor 5A.

[0152] In step 201, the wheel speeds n1-n4 of the first, second, third and fourth wheel speed sensors 5A, 5B, 5C and 5D are read into the ABS control, and in step 202 it is checked whether at least one of the wheel speeds cannot be read in because the corresponding wheel speed signal is missing or erroneous.

[0153] If the check in step 202 shows that all four wheel speeds n1-n4 can be detected without error ("yes"), then in step 203, these wheel speeds are read in and evaluated for performing normal ABS control. Otherwise ("no"), if, for example, the first wheel speed n1 of the first wheel speed sensor 5A cannot be detected, then in step 204, the first brake pressure p1 is determined based on the brake pressure p2 formed based on the detected second wheel speed n2, for example, in the above description in conjunction with Figure 5 As described.

[0154] In a further, now optional step 205, the simulated first brake pressure p1 of the brake actuator 4 for the first wheel 1A on the (one) first axle 2A is adapted as a function of the result of the friction coefficient difference detection, i.e., as a function of whether a friction coefficient difference situation is detected, for example, based on the wheel speed signal detected on the (other) second axle 2B. As a result, any detected friction coefficient difference situation is incorporated into the determination of the first brake pressure p1.

[0155] In a further step, likewise optional step 206 , a simulated first brake pressure p1 of brake actuator 4 for first wheel 1A on a first axle(s) 2A is adapted as a function of the detected or estimated axle load.

[0156] Finally, in step 208 , the first brake pressure p1 , which is optionally adapted and simulates the second brake pressure p2 , is converted, for example, into Figure 1 and Figure 2 The control target value of the pressure control module 20 is input to the brake actuator 4 of the first wheel 1A. As described above, steps 205 and 206 are optional in the method and can also be performed in any order, in particular in reverse order.

[0157] According to further specific embodiments, which are not described in detail here, no wheel speed sensor may be provided on at least one axle of the vehicle, for example on the second rear axle, so that no wheel speed signal is present there either. In such a configuration, step 202 of the method is then omitted, since it is already known that no wheel speed information is present for a specific wheel. However, wheel brake actuators for such wheels may also generate wheel-individual brake pressures if these wheel-individual brake pressures are determined as a function of at least one brake pressure of another axle, in particular by means of step 204 and optionally by means of steps 205 and 206.

[0158] In this case, the first brake pressure p1R on the right wheel of the second rear axle whose speed is not sensed can be determined, for example, based on the second brake pressure p2R of the right wheel on the same side of the first rear axle and based on the axle load ratio between the first and second rear axles. Similarly, the first brake pressure p1L on the left wheel of the second rear axle whose speed is not sensed can be determined, for example, based on the second brake pressure p2L of the left wheel on the same side of the first rear axle and based on the axle load ratio between the first and second rear axles.

[0159] Reference numerals list

[0160] 1A First Wheel

[0161] 1B Second wheel

[0162] 1C The third wheel

[0163] 1D The fourth wheel

[0164] 2A First axle

[0165] 2B Second axle

[0166] 3 Disc brakes

[0167] 4 Wheel brake actuator

[0168] 5A First wheel speed sensor

[0169] 5B Second wheel speed sensor

[0170] 5C Third wheel speed sensor

[0171] 5D 4th wheel speed sensor

[0172] 10 Compressed air reservoir

[0173] 13 Control circuit

[0174] 14 Supply lines

[0175] 14a Supply line

[0176] 14b Supply line

[0177] 14c Supply line

[0178] 15 Supply input (foot brake module)

[0179] 16 Control output (foot brake module, interface for VA and trailer)

[0180] 17 Control output (foot brake module, interface for HA)

[0181] 18 Service brake valve assembly

[0182] 19 Control input of the foot brake module

[0183] 20 Pressure regulation module

[0184] 22 Control line (for VA and trailer module 24)

[0185] 23 Control line (for HA)

[0186] 24 Trailer Control Module

[0187] 26 lines

[0188] 27 lines

[0189] 28 Pressure control valve

[0190] 29 Braking lines

[0191] 40 Primary electronic brake control device

[0192] 41 Secondary electronic brake control unit

[0193] 50 Brake line (to trailer)

[0194] 52 Primary supply sources

[0195] 58 Secondary Supply Sources

[0196] 80 Electro-pneumatic service brake

[0197] 82 Solenoid valve device

[0198] 83 Supply input terminal (solenoid valve device)

[0199] 84 Control output terminal (solenoid valve device)

[0200] 85 Control piston

[0201] 86 Braking value transmitter

[0202] 87 Tappet piston rod

[0203] 88 Double seat valve

[0204] 89 Storage Room

[0205] 90 Control Room

[0206] 91 Tappet piston

[0207] 92 Tappet receiving portion

[0208] 93 Driver Assistance Systems

[0209] 94 Service brake operating mechanism

[0210] 95 Pneumatic control input

[0211] 96 Pneumatic control input

[0212] 97 Electrical control input

[0213] Studio 98

[0214] 99 Exhaust connection

[0215] 100 Exhaust

[0216] 101 Data Connection Department

[0217] 102 Push rod piston compression spring

[0218] 103 Sleeve

[0219] 200 Flowchart

[0220] 201-208 Methods and Steps

[0221] SV1 (electronic) primary control connections

[0222] SV2 (electronic) secondary control connection

[0223] HA rear axle

[0224] VA front axle

[0225] BS Electric control signal

[0226] AS auxiliary brake request signal

[0227] F1 First Force

[0228] F2 Second Force

[0229] S1 First electric brake request signal

[0230] S2 Second electric brake request signal

[0231] p1 First pneumatic brake control pressure

[0232] P2 Second pneumatic brake control pressure

[0233] pSt Pneumatic control pressure

[0234] pVA Brake pressure on the front axle

[0235] pHA Braking pressure at rear axle

[0236] p Trailer Trailer brake pressure.

Claims

1. A method for determining or estimating a first brake pressure (p1) of a first brake actuator (4) for at least one first wheel (1A), wherein a brake device (80) actuated by a pressure medium comprises the first brake actuator, at which a brake pressure needs to be built up during a braking process and / or during regulation of a wheel speed signal, and at which a first wheel speed sensor is not present or a first wheel speed sensor (5A) is present but does not provide a first wheel speed signal (n1) or does not provide an error-free first wheel speed signal, wherein: The method comprises at least the following steps: a) during the braking process and / or during the implementation of the regulation, determining, measuring or estimating a second brake pressure (p2) of a second brake actuator (4) for at least one second wheel (1B), the braking device (80) comprising the second brake actuator, the second wheel being assigned a second wheel speed sensor (5b) which provides a wheel speed signal (n2), and b) determining or estimating the first brake pressure (p1) as a function of the second brake pressure (p2).

2. The method according to claim 1, characterized in that The adjustment includes: a) a vehicle dynamics control system (ESP) with a subordinate brake slip control function and / or drive slip control function and / or rollover protection function, and / or b) Brake slip control (ABS), and / or c) Drive slip regulation (ASR).

3. The method according to claim 1 or 2, characterized in that: A selection is made among the wheels (1A-1D) of the vehicle in order to identify at least one second wheel suitable for determining or estimating a first brake pressure (p1) of a first brake actuator (4) for the at least one first wheel (1A).

4. The method according to any one of the preceding claims, characterized in that A wheel (1B) arranged on the same axle (2A) as the first wheel (1A) is used as a second wheel.

5. The method according to any one of claims 1 to 3, characterized in that A wheel (1C, 1D) arranged on another axle (2B) relative to the axle (2A) on which the at least one first wheel (1A) is arranged is used as a second wheel.

6. The method according to claim 5, characterized in that The vehicle side relative to the at least one first wheel (1A) is arranged at a) on the same side of the vehicle, or b) The wheels (1C, 1D) on the other vehicle side serve as second wheels.

7. The method according to any one of the preceding claims, characterized in that During the braking process and / or while the regulation is being performed, a friction coefficient difference detection is performed in order to detect a friction coefficient difference situation.

8. The method according to claim 7, characterized in that The determination or estimation of the first brake pressure (p1) is also performed as a function of the identified friction coefficient difference situation.

9. The method according to claims 4 and 8, characterized in that a) using a wheel (1B) arranged on the same axle (2A) as the at least one first wheel (1A) as a second wheel, and b) A determination or estimation of the first brake pressure (p1) is also carried out as a function of the detected friction coefficient difference situation.

10. The method according to any one of the preceding claims, characterized in that Determining or estimating the axle load of the axle and / or the axle load distribution of the axle (2A, 2B) is performed.

11. The method according to claim 10, characterized in that The determination or estimation of the first brake pressure (p1) is also carried out as a function of the determined or estimated axle load or as a function of the determined or estimated axle load distribution.

12. The method according to claims 6 and 11, characterized in that A wheel (1C) which is arranged on another axle (2B) relative to the axle (2A) on which the at least one first wheel (1A) is arranged but on the same vehicle side as the at least one first wheel (1A) is used as a second wheel, and determination or estimation of the first brake pressure (p1) is also performed based on a determined or estimated axle load or based on a determined or estimated axle load distribution. 13 . A computer program having a program code for carrying out the method according to claim 1 , when the computer program is executed on a processor device.

14. A controller or a controller system (40, 41) having a processor device and a memory, the memory containing a computer program according to claim 13.

15. A pressure medium-actuated brake device (80) of a vehicle, the brake device being provided with at least one regulating device which receives and processes wheel speed signals of wheel speed sensors (5A-5D) as input signals, wherein: A brake actuator (4) is respectively assigned to the wheels (1A-1D) of the vehicle and a wheel speed sensor (5A-5D) is respectively assigned to at least some of the wheels of the vehicle, the wheel speed sensor generating a wheel speed signal corresponding to the wheel speed, and wherein the brake device (80) is designed to: a) determining or estimating a first brake pressure (p1) of a first brake actuator (4) for at least one first wheel (1A), the brake device (80) comprising the first brake actuator, at which a brake pressure is to be built up during a braking process and / or during the implementation of a regulation of processing wheel speed signals (n1-n4), and at which a first wheel speed sensor is not present or a first wheel speed sensor (5A) is present but does not provide a first wheel speed signal (n1) or does not provide an error-free first wheel speed signal, and b) determining, measuring or estimating a second brake pressure (p2) of a second brake actuator (4) for at least one second wheel (1B) during the braking process and / or during the implementation of the regulation, the braking device (80) comprising the second brake actuator, the second wheel being assigned a second wheel speed sensor (5B) which provides a wheel speed signal (n2), and c) determining or estimating the first brake pressure (p1) as a function of the second brake pressure (p2).

16. The braking device according to claim 15, characterized in that: The adjustment includes: a) a vehicle dynamics control system (ESP) with a subordinate brake slip control function and / or drive slip control function and / or rollover protection function, and / or b) Brake slip control (ABS), and / or c) Drive slip regulation (ASR).

17. The braking device according to claim 15 or 16, characterized in that: The brake device is designed to select among the wheels (1A-1D) of the vehicle in order to identify at least one second wheel suitable for determining or estimating the first brake pressure (p1).

18. The braking device according to any one of claims 15 to 17, characterized in that: The second wheel is a wheel (1B) arranged on the same axle (2A) as the first wheel (1A).

19. The braking device according to any one of claims 15 to 17, characterized in that: The second wheel is a wheel (1C, 1D) arranged on another axle (2B) relative to the axle (2A) on which the at least one first wheel (1A) is arranged.

20. The braking device according to claim 19, characterized in that: The second wheel is arranged on the vehicle side relative to the at least one first wheel (1A). a) on the same side of the vehicle, or b) Wheels (1C, 1D) on the other vehicle side.

21. The braking device according to any one of claims 15 to 20, characterized in that The braking device is designed to carry out a friction coefficient difference detection during the braking process and / or during the implementation of the control in order to detect a friction coefficient difference situation.

22. The braking device according to claim 21, characterized in that: The brake device is designed to also determine or estimate the first brake pressure (p1) as a function of the detected friction coefficient difference situation.

23. The braking device according to claims 18 and 22, characterized in that a) the second wheel is a wheel (1B) arranged on the same axle (2A) as the at least one first wheel (1A), and b) The brake device (80) is designed to also determine or estimate the first brake pressure (p1) as a function of the detected friction coefficient difference situation.

24. The braking device according to any one of claims 15 to 23, characterized in that The brake device is designed to determine or estimate an axle load of the axle (2A, 2B) and / or an axle load distribution of the axle (2A, 2B).

25. The braking device according to claim 24, characterized in that The brake device is designed to determine or estimate the first brake pressure (p1) also as a function of a determined or estimated axle load or as a function of a determined or estimated axle load distribution.

26. The braking device according to claims 19 and 25, characterized in that a) the second wheel is a wheel (1C) arranged on another axle (2B) relative to the axle (2A) on which the at least one first wheel (1A) is arranged, but arranged on the same vehicle side as the at least one first wheel (1A), and b) The brake device (80) is designed to determine or estimate the first brake pressure (p1) also as a function of a determined or estimated axle load or as a function of a determined or estimated axle load distribution.

27. The braking device according to any one of claims 15 to 26, characterized in that The brake device is an electropneumatic brake device with brake pressure control.

28. The braking device according to any one of claims 15 to 27, characterized in that The regulation is carried out in at least one controller or controller system (40, 41) of the brake device (80).

29. The braking device according to claim 28, characterized in that A primary controller (40) and a secondary controller (41) are provided, wherein the regulation is carried out in the primary controller (40) and / or in the secondary controller (41).

30. The braking device according to claim 29, characterized in that: At least some of the wheel speed sensors (5A-5D) are connected to the primary controller (40) and / or to the secondary controller (41) to transmit wheel speed signals.

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