Method for operating a braking system for a motor vehicle, corresponding braking system and computer program product

Abstract

The invention relates to a method for operating a braking system (1) for a motor vehicle, wherein the braking system (1) has an operating element (9) for specifying a braking force to be set. It is provided that, depending on a state variable of a drive device provided for driving the motor vehicle, a noise-generating operation of the braking system (1) is carried out at least temporarily, independently of the braking force to be set. The invention further relates to a braking system (1) for a motor vehicle and a computer program product.

Description

[0001] The invention relates to a method for operating a braking system for a motor vehicle, wherein the braking system has an operating element, particularly one that can be displaced along a displacement path, for specifying a braking force to be set. The invention further relates to a braking system for a motor vehicle and a computer program product.

[0002] For example, DE 10 2016 217 144 A1 is known from the prior art. This describes a method for haptic information feedback to a brake pedal of a motor vehicle. It involves comparing a current stability index describing the current driving situation with a stored critical stability index, whereby haptic information feedback is applied to the brake pedal of the motor vehicle if the ratio of the current stability index to the critical stability index exceeds a predetermined limit.

[0003] Furthermore, the document DE 10 2013 213 050 A1 discloses a method for regulating the restoring force of a control unit of motor vehicles. The control unit can be, for example, an accelerator pedal or a throttle grip, wherein actuation of the control unit by applying an actuating force causes a deflection of the control unit. A restoring force acts on the control unit, wherein the restoring force is directed opposite to the actuating force and in the direction of the initial position of the control unit, and wherein the control unit is deflected by a deflection angle. A desired angle of the deflection of the control unit is determined by a control loop, as is a current deflection of the control unit. The restoring force on the control unit is modulated depending on the difference between the current deflection and the desired angle.

[0004] It is an object of the invention to propose a method for operating a braking system for a motor vehicle, which has advantages over known methods, in particular provides a clearly recognizable feedback about a state of a system of the motor vehicle for a user of the motor vehicle.

[0005] This is achieved according to the invention with a method for operating a braking system for a motor vehicle having the features of claim 1. It is provided that, depending on a state variable of a drive device provided for driving the motor vehicle, a noise-generating operation of the braking system is carried out at least temporarily independently of the braking force to be set.

[0006] Advantageous embodiments with useful further developments of the invention are specified in the dependent claims. It should be noted that the exemplary embodiments explained in the description are not limiting; rather, any variations of the features disclosed in the description, the claims, and the figures are feasible.

[0007] The method serves to operate the braking system. The braking system is preferably a component of the motor vehicle, but can of course also be separate from it, in particular up to the point where the braking system is installed on or in the motor vehicle. The braking system serves to decelerate the motor vehicle, thus providing a braking force acting on at least one wheel of the motor vehicle. The braking force is applied to the at least one wheel by means of a wheel brake. Preferably, there are several wheels and accordingly several wheel brakes, wherein each of the wheel brakes is provided and designed to apply the braking force to one of the wheels.

[0008] The braking system can have any number of wheel brakes, with each of the wheel brakes being assigned to one of several wheels of the motor vehicle. Wherever this description refers to the wheel brake or the at least one wheel brake, the explanations are always transferable to one another. Explanations relating to the at least one wheel brake are therefore transferable to the wheel brake, and explanations relating to the wheel brake are transferable to the at least one wheel brake. If multiple wheel brakes are present, the explanations relating to the wheel brake are transferable to each of the multiple wheel brakes. The braking system is present as the service brake of the motor vehicle or at least forms a component of such a service brake.

[0009] The braking system features a control element for adjusting the braking force applied to the wheel by the wheel brake. The control element can be actuated by the user of the motor vehicle, preferably along the displacement path. The control element is located in an interior of the motor vehicle, but at least is accessible to the user from within the interior. For example, it is in the form of a brake pedal, meaning it is designed and constructed for foot operation by the user.

[0010] Without operation by the user, the control element is in an initial position. From this position, it can be moved by the user to a position different from the initial position, namely by applying an operating force. The braking system is intended and designed to exert a counterforce on the control element that is opposite to the operating force and is directed towards a displacement of the control element towards its initial position. If the counterforce is greater than the operating force, the control element is moved towards its initial position, in particular back to its initial position. For example, the counterforce is generated using a spring element connected to the control element.

[0011] The braking system, for example, has a master brake cylinder in which a master brake piston is displaceably arranged. The master brake piston, together with the master brake cylinder, limits a brake fluid volume that is variable, with its size depending on the position of the master brake piston. The master brake piston is coupled to the control element, which—as already mentioned—is, for example, the brake pedal. Using the control element, the user of the motor vehicle can set a desired braking force, which is referred to below as the specified braking force and is preferably fixedly related to a specified braking pressure.

[0012] The braking system is preferably an electro-hydraulic braking system. This means that in at least one operating mode of the braking system, the brake fluid present in the brake fluid volume does not directly provide the actual braking pressure applied to the wheel brake when the operating element is actuated, or at most provides a portion of it. Rather, when the operating element is actuated by the user of the motor vehicle, the specified braking pressure is determined and, from this, a target braking pressure is subsequently determined, to which the actual braking pressure applied to the wheel brake is set. The specified braking force is determined, for example, using at least one sensor which is assigned to the operating element and / or the master brake piston and / or the master brake cylinder and / or a simulator cylinder in which a simulator piston is displaceably arranged.

[0013] The sensor can be designed, for example, as a position sensor or as a pressure sensor. In the former case, the sensor is used to determine the position of the control element or the actuation distance of the control element by which the control element is displaced when actuated. Additionally or alternatively, the pressure present in the master brake cylinder is measured using the sensor. The specified brake pressure is then determined from the variable measured by the sensor, for example the position of the control element, the actuation distance and / or the pressure. The target brake pressure is determined from the specified brake pressure; for example, the target brake pressure is set equal to the specified brake pressure. An actual brake pressure that corresponds to the target brake pressure is then applied or set at the wheel brake.

[0014] The actual brake pressure is provided, for example, by a brake pressure source, which is preferably in the form of a pump, in particular an electrically operated pump. At least temporarily, the brake fluid volume is not, or at least not directly, fluidically connected to the wheel brake. In order to nevertheless provide the driver of the motor vehicle with haptic feedback when operating the control element, a brake force simulator is preferably assigned to the master brake cylinder. This simulator has a simulator piston, which is displaceably arranged in a simulator cylinder and is supported on a wall of the simulator cylinder via a spring element, thus subjecting it to spring force.

[0015] The simulator piston, together with the simulator cylinder, defines a simulator fluid volume that is variable, similar to the brake fluid volume. The size of the simulator fluid volume depends on the position of the simulator piston. The simulator fluid volume is fluidly connected to the brake fluid volume. When the control element is actuated, the brake fluid volume decreases, and brake fluid present in the brake fluid volume is supplied to the simulator fluid volume. The simulator fluid volume increases accordingly, causing the simulator piston to deflect against the spring force.

[0016] Depending on the spring force, which may depend on the deflection of the simulator piston, the flow connection between the simulator fluid volume and the brake fluid volume exerts a counterforce on the control element, which counteracts the operating force applied by the vehicle user. Accordingly, the driver receives haptic feedback via the control element, which essentially depends on the deflection of the control element from its initial or rest position.

[0017] To provide a fallback in the event of a brake system defect, for example, a failure of the brake pressure source, a direct flow connection is preferably provided between the master brake cylinder and the wheel brake. With such a brake system design, the actual brake pressure can be built up when the control element on the wheel brake is actuated, even in the event of a brake system defect. However, this requires the vehicle operator to apply a significantly greater operating force to the control element than usual.

[0018] Due to increasingly stringent emissions legislation for motor vehicles, driving a motor vehicle will in future only be permitted when the drive system is fully operational, and in particular, only when the vehicle's catalytic converter is fully preheated. This can be achieved, for example, by only allowing a gearshift lever or gear selector lever to be moved from a parked position once this condition is met. The user is typically informed via a display that they are not yet permitted to drive off. Today's gear selector levers usually no longer have a shift gate. Therefore, they are only moved forward or backward to select the current driving mode.

[0019] If the user of the motor vehicle fails to notice the display informing them that the vehicle is not yet ready to drive, they will attempt to make it ready to drive by moving the gearshift lever, but this will not be successful. This can have a negative impact on the user's mood. For this reason, a different procedure is chosen to indicate to the user that the vehicle is not ready to drive. This is by at least temporarily operating the noise-generating braking system, dependent on the state of the drive system, independently of the braking force to be set. In this way, the user receives immediate and comprehensible feedback on the state of the drive system via the control element, which they must operate anyway to drive.

[0020] Since the described procedure is preferably only performed when the motor vehicle is stationary, i.e., before the motor vehicle starts moving or can start moving, the driving operation of the motor vehicle is not adversely affected. Rather, the noise-generating operation of the braking system is only performed while the motor vehicle is stationary or while movement of the motor vehicle is prohibited. The user of the motor vehicle receives direct feedback on the status of the drive system via an additional sensory impression via the control element.

[0021] Noise-generating operation of the braking system means operating the braking system in such a way that it produces a noise that is easily recognizable and clearly audible to the user in the motor vehicle. Operating the braking system as a result of actuating a control element, for example, does not fall under this; rather, the noise should be generated independently of such actuation or the braking force to be set resulting from the actuation. Preferably, provision is made for operating the braking system to generate a fixed noise or a fixed noise sequence consisting of several noises, in particular a specific tone or a specific tone sequence consisting of several tones. For example, at a specific value of the state variable, the same noise is always generated, which evokes a specific impression in the user of the motor vehicle.This provides plausible feedback.

[0022] The noise sequence comprises, for example, a plurality of noises, each of the noises being assigned a specific noise parameter. In particular, different components of the braking system are operated for different noises and / or the braking system is operated to achieve different volumes. For example, a first noise in the noise sequence is generated with a first volume and a second noise in the noise sequence is generated with a second volume different from the first volume. One of the volumes can also be zero. For example, the noise sequence comprises a plurality of first noises with a volume different from zero, with a second noise with the lower second volume, in particular a volume of zero, being generated between every two of the first noises.

[0023] This braking system operation clearly and unmistakably indicates to the driver that the drive system, and thus the vehicle, is ready for operation. This creates an emotional bond between the user and the vehicle and avoids the adverse effects described above.

[0024] A further development of the invention provides that a state variable of an exhaust gas aftertreatment device of the drive device is used as the state variable. The drive device serves to drive the motor vehicle, thus providing a drive torque directed toward driving the motor vehicle. For this purpose, the drive device has a drive unit that at least partially generates the drive torque. The drive unit is embodied, for example, as an exhaust-generating drive unit, in particular as an internal combustion engine, or as an electric traction motor.

[0025] In the case of an internal combustion engine, the drive device has, in addition to the drive unit, an exhaust gas aftertreatment device to which the exhaust gas generated by the internal combustion engine is fed. The exhaust gas aftertreatment device serves to aftertreat the exhaust gas before it is discharged towards the external environment of the motor vehicle, in particular into the external environment. At least one state variable of the exhaust gas aftertreatment device is then used to carry out the noise-generating operation of the braking system, thus providing the driver with immediate feedback about the operating state. In particular, the braking system is used to deliberately generate a noise, preferably periodically, provided the state variable is less than a threshold value. If, however, it is greater than or equal to the threshold value, the braking system is no longer operated to generate the noise.

[0026] A further development of the invention provides that a temperature of the exhaust gas aftertreatment device is used as the state variable. The exhaust gas aftertreatment device comprises, for example, a vehicle catalytic converter and / or a particulate filter. The vehicle catalytic converter serves to catalytically convert at least one pollutant into a less hazardous product. The conversion rate at which this conversion occurs depends in particular on the temperature of the exhaust gas aftertreatment device. If the temperature corresponds to the operating temperature of the exhaust gas aftertreatment device, a comparatively high conversion rate is achieved. If the temperature deviates from the operating temperature, in particular if it is lower, the conversion rate also decreases.

[0027] To ensure adequate conversion of the pollutant into less hazardous products, it is necessary for the exhaust gas aftertreatment system to be at a temperature that at least approximately corresponds to its operating temperature. Heating of the exhaust gas aftertreatment system, in which the temperature changes toward the operating temperature, occurs, for example, through the exhaust gas of the internal combustion engine itself or by means of a heating device operated for this purpose. The described procedure enables plausible feedback to the user that the vehicle is not yet ready to drive.

[0028] A further development of the invention provides that during noise-generating operation of the braking system, at least one of the following components of the braking system is controlled to generate a noise: inlet valve, outlet valve, simulator valve, isolating valve, diagnostic valve, and actuator of a brake pressure source. The inlet valve serves to supply brake fluid to one or more wheel brakes, while the outlet valve discharges the brake fluid from one or more wheel brakes. The isolating valve is fluidically arranged between the master brake cylinder and the at least one wheel brake. In other words, the master brake cylinder is fluidically connected to the wheel brake via the isolating valve. For example, the isolating valve is fluidly connected to the wheel brake via the inlet valve, so that when the inlet valve and the isolating valve are open, brake fluid can flow from the master brake cylinder towards the wheel brake.

[0029] The simulator valve provides a fluidic connection between the simulator cylinder and the master brake cylinder. This means that the simulator cylinder is fluidically connected to the master brake cylinder via the simulator valve. When the simulator valve is closed, the simulator cylinder is fluidically decoupled from the master brake cylinder, so that at least no brake fluid can flow from the master brake cylinder toward the simulator cylinder or into the simulator cylinder. The diagnostic valve, for example, is fluidically arranged between a brake fluid reservoir and the master brake cylinder.

[0030] The brake pressure source serves to provide brake fluid at a specific pressure for the at least one wheel brake. The brake pressure source preferably has a pump that can be driven by the actuator. The actuator is in particular in the form of an electric motor. Provision can be made to control only one or precisely one of the mentioned components to generate the noise. Preferably, however, several or even all of the mentioned components are controlled, in particular to achieve the noise sequence. For example, the sounds of the noise sequence are generated using different components. This achieves the advantages already mentioned.

[0031] A further development of the invention provides that, during the noise-generating operation of the braking system, a component of the braking system is used that is attached to a resonator body. In order to generate a clearly audible noise using the braking system, the component that is operated for this purpose is attached to the resonator body. The resonator body is essentially any component of the motor vehicle that is suitable for transmitting the noise generated by the component into the interior of the motor vehicle, or even transmitting it in an amplified manner. For example, the resonator body is a component of the motor vehicle with a low mass compared to its length and sufficient vibration capability. This again serves to achieve the advantages already mentioned.

[0032] A further development of the invention provides that a wall, in particular a bulkhead, of the motor vehicle is used as the resonator body. The wall is preferably designed with a comparatively thin wall thickness so that it effectively transmits the noise generated by the braking system. In particular, the wall borders the interior of the motor vehicle, i.e., delimits it or is arranged within it. The wall is preferably a bulkhead of the motor vehicle, which can also be referred to as a firewall. The bulkhead separates the interior of the motor vehicle from an engine compartment, for example. The braking system or the component of the braking system is attached to the wall on the side facing away from the interior, in particular is attached in a sound-transmitting manner. This results in particularly effective introduction of the noise into the interior of the motor vehicle, so that the driver can clearly perceive it.

[0033] A further development of the invention provides that the component of the braking system with switchable damping is attached to the resonator body, and the damping is set to a lower value during noise-generating operation of the braking system than during non-noise-generating operation. During noise-generating operation, the component should generate a clearly audible noise. However, when the component is operated outside of noise-generating operation, noise should generally be avoided.

[0034] For this reason, it is preferably provided to fasten the component with the switchable damping to the resonator body, for example to the wall. A fastening means is arranged between the component and the resonator body, which holds the component to the resonator body. The fastening means is adjustable in terms of its damping; for example, a first setting results in lower damping and a second setting in higher damping. If the noise is to be generated using the braking system, the first setting is selected and set; otherwise, the second setting is selected. This prevents unwanted noise generation, but ensures that the desired noise generation is clearly audible to the user.

[0035] A further development of the invention provides that, during noise-generating operation of the braking system, several components of the braking system are controlled according to a stored control pattern for generating the noise. The control pattern contains the noise or the sequence of noises to be generated by the braking system or its components. The control pattern thus contains, for example, a sequence of several noises, as already described for the sequence of noises. With such a defined control pattern, the user of the motor vehicle can be provided with a clear indication of the state of the drive device.

[0036] The invention further relates to a braking system for a motor vehicle, in particular for implementing the method according to the explanations in the context of this description, comprising an operating element, in particular displaceable along a displacement path, for specifying a braking force to be set. The braking system is provided and configured to carry out noise-generating operation of the braking system, at least temporarily independent of the braking force to be set, depending on a state variable of a drive device provided for driving the motor vehicle.

[0037] The advantages of such a braking system design or such a procedure have already been pointed out. Both the braking system for a motor vehicle and the method for its operation can be further developed according to the explanations in the description, so reference is made to these in this regard.

[0038] The invention naturally also relates to a motor vehicle with such a braking system. Preferably, a noise-generating component of the braking system is attached to the resonator body of the motor vehicle. Preferably, the wall, for example, the bulkhead, is used as the resonator body.

[0039] The invention also relates to a computer program product comprising instructions that cause the braking system to execute the explained method according to the embodiments of this description. Regarding the advantages and possible advantageous developments, reference is made to the entire description.

[0040] The features and feature combinations described in the description, in particular the features and feature combinations described in the following description of the figures and / or shown in the figures, can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention. Thus, embodiments are also considered to be encompassed by the invention that are not explicitly shown or explained in the description and / or the figures, but which follow from or can be derived from the explained embodiments.

[0041] The invention will be explained in more detail below with reference to the exemplary embodiments shown in the drawings, without limiting the invention. Fig. 1 a schematic representation of a braking system for a motor vehicle.

[0042] The Fig.1 shows a schematic representation of a braking system 1 for a motor vehicle, which has a master brake cylinder 2, a brake force simulator 3, a brake pressure source 4, and wheel brakes 5, 6, 7, and 8. The number of wheel brakes is, of course, arbitrary. In the illustrated embodiment, four wheel brakes 5, 6, 7, and 8 are provided; however, a higher or lower number of wheel brakes may also be present. In the exemplary embodiment, wheel brakes 5 and 7 are assigned to wheels of a first wheel axle, in particular a front wheel axle, and wheel brakes 6 and 8 are assigned to wheels of a second wheel axle, in particular a rear wheel axle of the motor vehicle.

[0043] The master brake cylinder 2 is assigned an operating element 9, which is designed here as a brake pedal. The operating element 9 is coupled to a master brake piston 10, for example, via a lever connection. The master brake piston 10 is arranged displaceably in the master brake cylinder 2. In the illustrated embodiment, in addition to the master brake piston 10, a further brake piston 11 is arranged in the master brake cylinder 2. However, this is optional.

[0044] The master brake piston 10, together with the master brake cylinder 2, encloses a brake fluid volume 12. This volume is fluidly connected to a simulator fluid volume 13 of the brake force simulator 3. The simulator fluid volume 13 is delimited by a simulator piston 14 together with a simulator cylinder 15, in which the simulator piston 14 is displaceably arranged. The simulator piston 14 is preferably spring-loaded by at least one spring element 16. The spring element 16 exerts a spring force on the simulator piston 14, which counteracts an increase in the simulator fluid volume 13.

[0045] A sensor (not shown here) is assigned to the master brake cylinder 2 and / or the control element 9, by means of which a preset brake pressure is determined upon actuation of the control element 9 and, from this, a target brake pressure is determined. Subsequently, an actual brake pressure generated by the brake pressure source 4, which corresponds to the target brake pressure, is applied to at least one wheel brake 5, 6, 7, and 8. The brake pressure source 4 is illustrated here by way of example as a pump, which is driven or can be driven by an electric motor 17.

[0046] A switching valve 18, which can also be referred to as a simulator valve, is arranged fluidically between the brake fluid volume 12 and the simulator fluid volume 13. A check valve 19 is arranged fluidically parallel to the switching valve 18. The check valve 19 is designed such that it opens in the direction of the wheel brake 5, 6, 7, or 8, thus allowing a flow of brake fluid from the simulator fluid volume 13, but preventing a flow toward the simulator fluid volume 13.

[0047] Inlet valves 20, 21, 220 and 23 are assigned to the wheel brakes 5, 6, 7 and 8, namely the inlet valve 20 to the wheel brake 5, the inlet valve 21 to the wheel brake 6, the inlet valve 22 to the wheel brake 7 and the inlet valve 23 to the wheel brake 8. Furthermore, outlet valves 24, 25, 26 and 27 are assigned to the wheel brakes 5, 6, 7 and 8, namely the outlet valve 24 to the wheel brake 5, the outlet valve 25 to the wheel brake 6, the outlet valve 26 to the wheel brake 7 and the outlet valve 27 to the wheel brake 8.

[0048] In addition, the brake system 1 has isolation valves 28, 29, 30 and 31. The inlet valves 20 and 21 are connected in parallel in terms of flow to the isolation valves 28 and 29 and via these to the master brake cylinder 2 and the brake pressure source 4, more precisely via the isolation valve 28 to the master brake cylinder 2 and via the isolation valve 29 to the brake pressure source 4. Analogously, the inlet valves 22 and 23 are connected in parallel in terms of flow to the isolation valves 30 and 31 and via these to the master brake cylinder 2 and the brake pressure source 4, more precisely via the isolation valve 30 to the brake pressure source 4 and via the isolation valve 31 to the master brake cylinder 2.

[0049] This means that the isolation valves 28 and 31 are each connected to the master brake cylinder 2, in particular the isolation valve 28 to the brake fluid volume 12, and the isolation valve 31 either also to the brake fluid volume 12 or to another brake fluid volume 32 located on the side of the brake piston 11 facing away from the brake fluid volume 12. The brake fluid volume 32 is limited by the brake piston 11 together with the master brake cylinder 2.

[0050] The separating valves 29 and 30 are fluidically connected in parallel to the brake pressure source 4. The outlet valve 24 is fluidically connected between the inlet valve 20 and the wheel brake 5, the outlet valve 25 is fluidically connected between the inlet valve 21 and the wheel brake, the outlet valve 26 is fluidically connected between the inlet valve 22 and the wheel brake 7, and the outlet valve 27 is fluidically connected between the inlet valve 23 and the wheel brake 8.

[0051] Via the outlet valves 24, 25, 26, and 27, the respective wheel brakes 5, 6, 7, and 8 are fluidly connected to a brake fluid reservoir 33. This reservoir is also fluidly connected to the brake pressure source 4 via a check valve 34 and to the master brake cylinder 2 via a valve arrangement 35. The valve arrangement 35 comprises, for example, a switching valve 36 and a check valve 37, which are fluidly connected to one another. The switching valve 36 is preferably a diagnostic valve, which is actuated in particular during a diagnosis of the brake system 1.

[0052] The braking system 1 is adjusted, at least temporarily, depending on a state variable of a drive direction of the motor vehicle (not shown here). Preferably, the braking system 1 is designed to generate a noise in a targeted manner, particularly if a state variable of the drive device 1 is less than a threshold value. However, if the state variable is equal to or greater than the threshold value, the noise generation is stopped.

[0053] The noise is generated in particular by periodically opening and closing at least some of the intake valves 20 to 23, the exhaust valves 24 to 27, the isolation valves 28, 29, 30, and 31, and the switching valve 18. The electric motor 17 can also be operated to generate noise. This provides a user of the motor vehicle with immediate and comprehensible acoustic feedback regarding the motor vehicle's readiness to drive. LIST OF REFERENCE SYMBOLS: 1 braking system 2 master brake cylinders 3 brake force simulator 4 Brake pressure source 5 wheel brake 6 wheel brake 7 Wheel brake 8 Wheel brake 9 Control element 10 master brake pistons 11 brake pistons 12 brake fluid volume 13 Simulator fluid volume 14 simulator pistons 15 simulator cylinders 16 spring element 17 Electric motor 18 Switching valve 19 Check valve 20 Inlet valve 21 Inlet valve 22 Inlet valve 23 Inlet valve 24 Exhaust valve 25 Exhaust valve 26 Exhaust valve 27 Exhaust valve 28 Isolating valve 29 Isolating valve 30 Isolating valve 31 Isolating valve 32 brake fluid volume 33 Brake fluid reservoir 34 Check valve 35 Valve arrangement 36 switching valve 37 Check valve QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2016 217 144 A1

[0002] DE 10 2013 213 050 A1

[0003]

Claims

[1] Method for operating a braking system (1) for a motor vehicle, wherein the braking system (1) has an operating element (9) for specifying a braking force to be set, characterized by that, depending on a state variable of a drive device provided for driving the motor vehicle, a noise-generating operation of the braking system (1) is carried out at least temporarily independently of the braking force to be set. [2] Method according to claim 1, characterized by that a state variable of an exhaust gas aftertreatment device of the drive device is used as the state variable. [3] Method according to one of the preceding claims, characterized by that a temperature of the exhaust gas aftertreatment device is used as the state variable. [4] Method according to one of the preceding claims, characterized bythat during the noise-generating operation of the braking system (1), at least one of the following components of the braking system (1) is controlled to generate a noise: inlet valve (20, 21, 22, 23), outlet valve (24, 25, 26, 27), simulator valve (18), isolating valve (28, 29, 30, 31), diagnostic valve (36) and actuator of a brake pressure source (4). [5] Method according to one of the preceding claims, characterized by that in the noise-generating operation of the braking system (1), a component of the braking system (1) is used which is attached to a resonator body. [6] Method according to one of the preceding claims, characterized by that a wall is used as the resonator body. [7] Method according to one of the preceding claims, characterized bythat the component of the braking system (1) with switchable damping is attached to the resonator body and the damping is set to a lower value during the noise-generating operation of the braking system (1) than outside the noise-generating operation. [8] Method according to one of the preceding claims, characterized by that during the noise-generating operation of the braking system (1), several components of the braking system (1) are controlled according to a stored control pattern to generate noise. [9] Braking system (1) for a motor vehicle, in particular for carrying out the method according to one or more of the preceding claims, with an operating element (9) for specifying a braking force to be set, characterized bythat the braking system (1) is provided and designed to carry out a noise-generating operation of the braking system (1) at least temporarily independently of the braking force to be set, depending on a state variable of a drive device provided for driving the motor vehicle. [10] Computer program product comprising instructions causing the braking system (1) according to claim 9 to carry out the method according to one or more of claims 1 to 8.

Images