DE102015212188A1 - Method for operating an on-board brake system with an electric motor and control device for at least one electric motor of an on-board brake system - Google Patents

Abstract

The invention relates to a method for operating an on-board brake system with an electric motor, comprising the steps of: determining at least one brake default quantity (s) with respect to a requested target vehicle deceleration and executing the requested target vehicle deceleration at least temporarily using the electric motor, by at least one target magnitude with respect to a desired engine braking torque to be effected taking into account a predetermined or defined characteristic curve (k) and the at least one brake specification variable (s) is determined and the electric motor is driven accordingly, wherein at least once setting (P) of the characteristic (k) taking into account at least current information (I1) with respect to at least one clearance of at least one wheel brake cylinder of the brake system and / or at least one volume-pressure relation of at least one brake circuit of the brake system. Likewise, the invention relates to a control device for at least one electric motor of an on-board brake system. Furthermore, the invention relates to an electric motor for an on-board brake system and a brake system for a vehicle.

Description

The invention relates to a method for operating an on-board brake system with an electric motor. Likewise, the invention relates to a control device for at least one electric motor of an on-board brake system. Furthermore, the invention relates to an electric motor for an on-board brake system and a brake system for a vehicle.

State of the art

The DE 10 2012 211 278 A1 , the DE 10 2012 222 974 A1 and the DE 10 2012 222 978 A1 describe methods for operating on-board brake systems and appropriately designed control devices. In performing one of the respective methods, a desired vehicle deceleration requested by a driver of a vehicle equipped with the operated braking system is preferably effected solely by means of a recuperative operation of an electric motor designed to brake the vehicle. In order to limit or prevent an undesirable build up of brake pressure in at least one wheel brake cylinder of the brake system during recuperative operation of the electric motor, a brake fluid volume forced out by the driver upon request of the target vehicle deceleration from a master brake cylinder of the brake system is opened by opening at least one valve in at least one storage volume postponed. At the same time, the driver's braking request is fulfilled by the electric motor being driven, taking into account the desired vehicle deceleration requested by the driver, such that the requested desired vehicle deceleration is at least partially effected by means of the electric motor.

Disclosure of the invention

The invention provides a method for operating an on-board brake system with an electric motor having the features of claim 1, a control device for at least one electric motor of an on-board brake system with the features of claim 5, an electric motor for an on-board brake system with the features of claim 9 and Braking system for a vehicle with the features of claim 10.

Advantages of the invention

The present invention provides easily realizable possibilities for effecting an at least one-off adaptation of a relation between the requested target vehicle deceleration and the actual engine braking torque caused by the electric motor such that the driver automatically fulfills his request for the target vehicle deceleration to at least one clearance and / or at least one a current hydraulic stiffness of at least one brake circuit adapts. In particular, the present invention also provides a periodic / regular or continuous adaptation of the relation between the requested target vehicle deceleration and the actual engine braking torque of the electric motor. As will be explained in more detail below, in a use of the present invention, the driver is also during a braking, the requested target vehicle deceleration is effected solely by means of the electric motor, stimulated his request the target vehicle deceleration to the at least one clearance and / or the adjust current hydraulic stiffness of the at least one brake circuit. This ensures that at a transition of the braking system from a purely recuperative braking mode (in which the requested target vehicle deceleration is effected solely by the electric motor) or a combined hydraulic-recuperative braking mode (in which the requested target vehicle deceleration partially by means of the electric motor and partially caused by a brake pressure increase in the at least one wheel brake cylinder) in a purely hydraulic braking mode (in which the requested target vehicle deceleration is carried out only by a corresponding increase in brake pressure in the at least one wheel brake cylinder of the brake system) the driver no (noticeable / noticeable) deceleration fluctuation noticed. This improves braking comfort of the brake system equipped with the electric motor.

In an advantageous embodiment of the method, at least one lateral acceleration of the vehicle during a time interval after a last brake pressure build-up in the at least one wheel brake cylinder is determined as the at least one current information regarding the at least one clearance of the at least one wheel brake cylinder. Subsequently, the at least one lateral acceleration as the at least one current information regarding a probability for the presence of the at least one clearance in the at least one wheel brake cylinder, a size of at least one clearance and / or one to overcome the respective clearance in the at least one wheel brake cylinder to be introduced additional volume be evaluated. Taking into account at least one of the enumerated variables in the (re) determination of the characteristic curve automatically creates a relationship between the requested target vehicle deceleration and the actual actual engine braking torque so that the driver, when requesting the target vehicle deceleration, has an additional (to overcome of the possibly present at least one Clearance sufficient) brake fluid volume from the master cylinder shifts. The additional volume of brake fluid can thus be cached during execution of the target vehicle deceleration exclusively by means of the electric motor in at least one memory of the brake system, so that at a deactivation of the electric motor and a subsequent execution of the requested target vehicle deceleration exclusively by means of a brake pressure build-up in the at least one Wheel brake cylinder is the additional volume of brake fluid to overcome the at least one clearance in it.

In a further advantageous embodiment of the method, as the at least one actual information relating to the at least one volume-pressure relation of the at least one brake circuit occurring delay difference, pressure difference and / or braking torque difference at a transition of the brake system from a first operating mode of the brake system, in which a previously requested desired vehicle deceleration is first met exclusively or partially by means of the electric motor, in a second operating mode of the brake system, in which the previously requested desired vehicle deceleration is later fulfilled exclusively by means of the at least one wheel brake cylinder. In particular, it can be seen from a delay difference occurring in such a transition, whether a hydraulic rigidity of the at least one brake circuit is below the (not yet currently adapted) characteristic curve. By means of a subsequent (re) definition of the characteristic line taking into account the at least one current information, the characteristic curve can subsequently be adapted such that a desired adaptation of the characteristic curve to the current hydraulic rigidity of the at least one brake circuit is present.

As a supplement or as an alternative to the previously described embodiments, as the at least one actual information relating to the at least one volume-pressure relation of the at least one brake circuit, a relation between a time increase of an adjustment path of at least one of the driver at a previous request of a target Vehicle deceleration adjusted brake actuator and an increase in time of at least one brake pressure in the at least one wheel brake cylinder can be determined. On the basis of such a relationship, it is above all recognizable whether the current hydraulic rigidity of the at least one wheel brake cylinder is above the (not yet updated) characteristic curve. In this case too, the desired adaptation of the characteristic curve to the current hydraulic rigidity of the at least one brake circuit can be created by means of (re) definition of the characteristic curve.

The advantages described above are also ensured in a corresponding control device for at least one electric motor of an on-board brake system. It should be noted that the control device according to the above-described embodiments of the method for operating an on-board brake system with an electric motor can be further developed.

Further, an electric motor for an on-vehicle brake system and a brake system for a vehicle each provided with such a control device also provide the advantages described above. Also in this case, the control device according to the above-described embodiments of the method for operating an on-board brake system can be further developed.

Brief description of the drawings

Further features and advantages of the present invention will be explained below with reference to the figures. Show it:

1a and 1b Coordinate systems for explaining a first embodiment of the method for operating an on-board brake system with an electric motor;

2 a coordinate system for explaining a second embodiment of the method for operating an on-board brake system with an electric motor; and

3 a schematic representation of an embodiment of the control device for at least one electric motor of an on-board brake system.

Embodiments of the invention

In the following, various embodiments of the method for operating an on-board brake system with an electric motor and a control device for at least one electric motor of an on-board brake system will be described. An executability of the described methods and a usability of the corresponding control device are limited neither to a specific brake system type of the on-board brake system nor to a specific vehicle type / type of vehicle of the vehicle / motor vehicle equipped therewith. For example, the methods of operating each of the in the DE 10 2012 211 278 A1 , of the DE 10 2012 222 974 A1 and the DE 10 2012 222 978 A1 described conventional brake systems are executed. The embodiments of the method for operating an on-board brake system with an electric motor described below can also be combined with the conventional methods described in the publications. In addition, the control device can be used in any of the conventional brake systems described.

The reference made here to the DE 10 2012 211 278 A1 , the DE 10 2012 222 974 A1 and the DE 10 2012 222 978 A1 for the feasibility of the embodiments of the method for operating an on-board brake system with an electric motor and the usability of the corresponding control device is to be interpreted only as an example. The embodiments of the method for operating an on-board brake system with an electric motor and the corresponding control device can be used for (almost) any brake system of a vehicle with an electric motor. The electric motor can be understood to mean an (electric) engine by means of which an actual engine braking torque can be exerted on at least one wheel of the respective vehicle and / or at least one axle of the respective vehicle so that the vehicle is caused by at least the actual engine braking torque Actual vehicle deceleration slowed or decelerated to a standstill. The electric motor can in particular be designed so that by means of its (recuperative / regenerative) operation for braking the vehicle, a kinetic energy of the vehicle can be converted into electrical energy and stored on a storage unit / battery. As an alternative or as a supplement thereto, the electric motor can also be a drive motor for (optionally) accelerating the vehicle. It should be noted, however, that a feasibility of the electric motor is not limited to a particular type of engine.

1a and 1b show coordinate systems for explaining a first embodiment of the method for operating an on-board brake system with an electric motor.

When carrying out the method described below, (when a brake actuation element / brake pedal is actuated by a driver of the vehicle) at least one brake specification variable with respect to a desired vehicle deceleration requested by the driver is determined. The at least one brake specification variable may, for example, correspond to an actuation strength of the actuation of the brake actuation element / brake pedal by the driver. In particular, an adjustment path of the brake operating element / brake pedal, an adjustment path of a driver brake power transmission component connected to the brake operating element / brake pedal and / or a driver braking force exerted by the driver on the brake operating element / brake pedal can be determined as the at least one brake default variable. At least one brake actuation element sensor, such as, for example, a brake pedal travel sensor, a rod travel sensor, a differential travel sensor and / or a driver brake force sensor, may be used to determine the at least one brake specification variable. The thus determined at least one brake specification amount usually corresponds to an amount of the requested target vehicle deceleration, which the driver requests by the operational strength of his operation of the brake operating member / brake pedal.

The requested target vehicle deceleration is performed at least temporarily using the electric motor. This has the advantage that by means of the operation of the electric motor for braking the vehicle, a kinetic energy of the vehicle is converted into electrical energy. The electrical energy obtained by means of the regenerative / recuperative operation of the electric motor can be temporarily stored in at least one storage unit / battery of the vehicle and recalled later if necessary. Performing the requested target vehicle deceleration at least at times using the electric motor thus reduces energy consumption of the vehicle, and possibly also pollutant emission of the vehicle, during a journey.

Preferably, the requested target vehicle deceleration is as often as possible carried out exclusively by means of the electric motor, in order to obtain as much electrical energy as possible in this way. However, the electric motor for braking the vehicle can only be used if the at least one storage unit / battery is not yet fully charged and the vehicle is traveling at a speed of at least one minimum speed necessary for regenerative / recuperative operation of the electric motor.

It is therefore usually not possible to brake the vehicle only by means of the electric motor to its standstill. The equipped with the electric motor vehicle brake system therefore usually includes at least one wheel brake cylinder which is connected via at least one brake circuit to a master cylinder of the brake system. Thus, as soon as the electric motor for braking the vehicle is no longer usable, by means of a brake pressure build-up in the at least one wheel brake cylinder, an actual friction braking torque Mhyd of at least a wheel brake cylinder on the at least one wheel of the vehicle to be effected so that the attributable actual engine braking torque Mm of the electric motor by means of the (re-effected) actual friction braking torque Mhyd of the at least one wheel brake cylinder is compensated.

This process is often called a "blind". This can also be described by the fact that the brake system from a first operating mode, in which the requested target vehicle deceleration (almost / up to a residual Reibbremsmoment the at least one wheel brake cylinder of almost zero) is met exclusively by means of the electric motor, in a second operating mode is transferred, being met in the second operating mode, the requested target vehicle deceleration (substantially) exclusively by means of at least one wheel brake cylinder. In the following, the first operating mode is referred to as purely recuperative braking mode and the second operating mode as purely hydraulic braking mode.

Preferably, in the method described here, the requested target vehicle deceleration, if the at least one storage unit / battery is not fully charged and / or the speed of the vehicle is above the necessary for regenerative / recuperative operation of the electric motor minimum speed (almost / up to the residual friction braking torque of the at least one wheel brake cylinder of almost zero) is effected exclusively by means of the electric motor. This is done by setting at least one desired value with respect to a desired engine braking torque to be effected by the electric motor on the at least one wheel of the vehicle and / or the at least one axle of the vehicle, taking into account a predetermined or defined characteristic k and the at least one brake specification variable , Subsequently, the electric motor is controlled such that the requested target vehicle deceleration (at least partially / except for the residual friction braking torque of the at least one wheel brake cylinder of almost zero) by means of the target engine braking torque corresponding to the at least one wheel and / or the at least one Axis caused actual engine braking torque Mm is performed.

An example of the characteristic k is in the coordinate system of 1a entered. In the coordinate system of 1a An abscissa represents a bar path s as an example of the at least one brake default quantity, while an ordinate indicates a brake torque M. (Instead of the braking torque M, the at least one setpoint variable can also be another characteristic of an operation of the electric motor.)

The characteristic curve k can be rewritten as a function which fixes the desired engine braking torque of the electric motor (directly or via the at least one setpoint variable) to be effected in the purely recuperative braking mode as a function of the at least one brake specification variable. The characteristic curve k is preferably based on an output characteristic curve stored before / during startup of the brake system, by means of which an output relation between the at least one brake specification value and the desired engine braking torque to be effected in the purely recuperative braking mode is determined (directly or indirectly) in that the setpoint engine braking torque defined for the purely recuperative braking mode corresponds (substantially) to the actual friction braking torque Mhyd produced by means of the at least one respective brake specification variable in the purely hydraulic braking mode. This can also be described by the fact that the output characteristic curve (essentially) corresponds to an original / initial hydraulic rigidity of the at least one brake circuit before / during startup of the brake system, from which an output ratio between the at least one brake specification variable (or an in In this case, the brake fluid volume displaced from the master brake cylinder into the brake fluid volume displaced by at least one brake circuit) and the actual friction brake torque Mhyd produced in the purely hydraulic braking mode results.

In a preferred embodiment of the method described here, as soon as the electric motor can no longer be used regeneratively / recuperatively, the (dispensing) actual engine braking torque Mm of the electric motor is replaced by an actual friction braking torque Mhyd of the at least one wheel brake cylinder. This process is in 1b depicted:
The coordinate system of 1b has as its abscissa a time axis t, while an ordinate of the coordinate system of 1b a total braking torque Mtotal exerted on the vehicle from the actual engine braking torque Mm and the actual friction braking torque Mhyd. In the example of 1b is the requested target vehicle deceleration (except for possibly the residual Reibbremsmoment the at least one wheel brake cylinder of approximately zero) effected exclusively by means of the electric motor up to a time t1. The total braking torque Mtotal is thus (almost) equal to the actual engine braking torque Mm up to the time t1. This can also be described by the fact that the brake system is present in the purely recuperative braking mode until time t1.

Preferably, in the purely recuperative braking mode, a brake fluid volume forced out by the driver when requesting the target vehicle deceleration (actuation of the brake operating member / brake pedal) from the master cylinder of the brake system is at least one memory of the brake system (eg a low-pressure storage chamber) temporarily stored. Possibilities for carrying out the purely recuperative braking mode, for example, in DE 10 2012 211 278 A1 , of the DE 10 2012 222 974 A1 and in the DE 10 2012 222 978 A1 described.

From time t1, the brake system is transferred from the pure recuperative braking mode to the purely hydraulic braking mode. For example, for this purpose, the electric motor is deactivated, while the cached brake fluid volume in the at least one brake circuit (and thus in the at least one wheel brake cylinder) is transferred. From the time t1, therefore, an increase of the actual friction braking torque Mhyd of the at least one wheel brake cylinder begins until the time t2. Until the time t3, the electric motor is "shut down". From time t3, the total braking torque Mtotal is thus equal to the actual friction braking torque Mhyd of the at least one wheel brake cylinder.

However, the hydraulic rigidity of the at least one brake circuit often changes after the startup of the brake system. In particular, aging effects and / or a temperature can lead to sustained changes in the hydraulic rigidity of the at least one brake circuit. In the example of 1b For example, the hydraulic rigidity of the at least one brake circuit has a change that requires a larger volume of brake fluid to effect a particular brake pressure (versus the original / initial hydraulic stiffness). While before / at the time of operation of the brake system from the time t1 in the at least one brake circuit back transferred brake fluid volume would cause a "standard Reibbremsmoment" Mhyd0, the actual friction braking Mhyd of at least one wheel brake cylinder at time t3 is significantly smaller.

The actual friction braking torque Mhyd of the at least one wheel brake cylinder established at the time t2 is therefore also smaller than the actual engine braking torque Mm of the electric motor present up to the instant t1. The total braking torque Mtotal thus experiences between the times t2 to t3 a braking torque difference Δ, so that even a brake torque difference corresponding delay difference at the transition of the brake system from the purely recuperative braking mode in the purely hydraulic braking mode is determined.

By means of the method described here, however, a repeated occurrence of a significant delay difference in a transition from the purely recuperative braking mode into the purely hydraulic braking mode can be prevented. For this purpose, the characteristic curve k is determined at least once (new) taking into account at least one current information I1 relating to at least one volume-pressure relation of the at least one brake circuit of the brake system. By way of example, in the embodiment of the 1a and 1b the delay difference occurring at the transition of the brake system from the purely recuperative braking mode into the purely hydraulic braking mode is determined as the at least one actual information I1 with respect to the at least one volume-pressure relation of the at least one brake circuit. The subsequent at least one (new) setting of the characteristic k taking into account the at least one current information I1 is indicated by the arrow P in the 1a played. (As an alternative or in addition to a delay difference, a corresponding pressure and / or braking torque difference can also be used.)

By means of the graph I1 as the at least one current information I1 is in 1a indicated that the altered hydraulic stiffness of the brake system requires a larger volume of brake fluid to effect a particular actual friction brake torque Mhyd (versus the output ratio). However, due to the at least one (new) definition of the characteristic k taking into account the at least one current information I1, the characteristic k (as a newly defined characteristic kc) can be adapted to the changed hydraulic rigidity of the at least one brake circuit. The driver is thus already in the purely recuperative braking mode by the "reduction of the characteristic k" excited to squeeze out more brake fluid from the master cylinder to effect a certain target vehicle deceleration. Thus it is ensured that also with a subsequent transition from the purely recuperative Braking mode in the purely hydraulic braking mode is sufficient brake fluid for complete blending of the applicable actual engine braking torque Mm (by building an actual friction brake torque Mhyd equal to the actual engine braking torque Mm) is available. In the 1a reproduced adaptation of the characteristic k thus leads to the fact that in the next braking, a newly defined characteristic curve kc better adapted to the actual hydraulic rigidity present.

By means of a repeated determination of the characteristic curve k in the manner described above, a continuous adaptation of the characteristic k can also be carried out. Since a change in the hydraulic stiffness of the at least one brake circuit is usually not abrupt, but over a longer period of time, the adjustment of the characteristic can already be done after braking, in which the delay difference occurring during the transition from the purely recuperative braking mode in the pure hydraulic brake mode is still so low that it is imperceptible to the driver. Therefore, a driver notices when using the means of 1a and 1b reproduced method even after the occurrence of significant aging effects that affect the hydraulic stiffness of the at least one brake circuit, little delay fluctuations in the transition from the purely recuperative braking mode in the purely hydraulic braking mode. A braking comfort of the vehicle's brake system is thus still guaranteed even after a long-time commissioning or after a long operation.

2 shows a coordinate system for explaining a second embodiment of the method for operating an on-board brake system with an electric motor. Also in the coordinate system of 2 An abscissa represents a bar path s as an example of the at least one brake default quantity, while an ordinate indicates a brake torque M.

In addition to differences in the method of 2 compared with the previously described embodiment. It is noted, however, that the procedure of 2 may also include the previously mentioned process steps.

In the embodiment of the 2 is as the at least one current information I2 with respect to the at least one volume-pressure relation of the at least one brake circuit, a relation between an increase in the rod travel s and an increase in time at least one brake pressure in the at least one wheel brake cylinder (or the resulting actual friction brake Mhyd of at least one wheel brake cylinder) during at least one executed in the purely hydraulic braking mode braking determined. In this way, it is also possible to determine a graph I 2 for the hydraulic rigidity of the at least one brake circuit during the at least one braking performed in the purely hydraulic braking mode. In addition, instead of the rod path s, another variable with respect to an adjustment path of at least one brake actuation element adjusted by the driver when requesting the desired vehicle deceleration or a driver brake force transmission component connected thereto can also be evaluated.

As the braking performed in the purely-hydraulic braking mode, any braking can be used in which the braking of the brake operating element / brake pedal is not restrained from the beginning of actuation of the brake operating element / brake pedal until the brake operating element / brake pedal is completely released. This is the case, for example, when braking at a low vehicle speed, e.g. when parking in and out, is requested, a temperature is too high and / or the at least one storage unit / battery is fully loaded.

In the example of 2 is the hydraulic rigidity of the at least one brake circuit above the (not yet updated) characteristic k. By means of in 2 figuratively reproduced redefinition of the characteristic k (as a newly-established / updated characteristic kc), however, an advantageous adaptation is possible even in such a situation.

For all the methods described above, the fact is exploited that during the respective braking, the hydraulic fluid is displaced only within the brake system. The above-described embodiments of the method for operating an on-board brake system with an electric motor may also be combined into a common method.

In addition, each of the embodiments described above, or a combination of the two embodiments, be further developed by the at least once (re) defining the characteristic additionally taking into account at least one current information regarding at least one clearance of at least one wheel brake cylinder of the brake system. An alternative definition of the characteristic curve taking into account the at least one actual information regarding the at least one clearance of the at least one wheel brake cylinder instead of taking into account the at least one actual information I1 or I2 with respect to the at least one volume-pressure relation of the at least one brake circuit is possible.

This can also be targeted to a short-term increase in volume of the brake system. The reason for such a short-term increase in the volume of the brake system is an increase in the so-called clearance, by means of which a distance of the brake disc to the brake pad is beschzeichenbar. This distance can increase significantly, for example, during long journeys without braking or when driving with large lateral acceleration.

Such an increase in the distance is responsive by at least one lateral acceleration of the vehicle during a time interval after a last Brake pressure build-up in the at least one wheel brake cylinder is determined as the at least one current information with respect to the at least one clearance of the at least one wheel brake cylinder. Likewise, a brakeless driving time after the last brake pressure build-up in the at least one wheel brake cylinder can be determined as the at least one current information regarding the at least one clearance of the at least one wheel brake cylinder. Subsequently, by means of the at least one current information about a possibly increased clearance in advance already the characteristic k be set so that a possibly worse response of the wheel brake cylinder by an additional volume of brake fluid to overcome the at least one clearance can be bypassed. The conventionally occurring poor response of the at least one wheel brake cylinder for achieving a desired braking effect can thus be avoided by means of the procedure described here. Sensors for determining the at least one lateral acceleration and / or the travel time after the last brake pressure build-up in the at least one wheel brake cylinder are conventionally already installed on a vehicle. To carry out the advantageous procedure described here, therefore, no additional sensors on the vehicle are necessary.

All embodiments described above are suitable for a continuous adaptation of the characteristic curve k over a plurality of braking operations, so that no deceleration fluctuations occur when there is a transition from a purely recuperative braking mode to a purely hydraulic braking mode of the brake system.

It should be noted that in all of the embodiments described above, veneering operations are also executable so as to have no effect on a braking distance of the vehicle. Further, a stiffness of the brake operating member / brake pedal can be adjusted so that the driver has an advantageous (standard) brake operation feeling (pedal feel) regardless of whether the requested target vehicle deceleration is purely recuperative or purely hydraulic. Possibilities for adjusting the rigidity of the brake operating member / brake pedal are already in the DE 10 2012 211 278 A1 , of the DE 10 2012 222 974 A1 and in the DE 10 2012 222 978 A1 described.

3 shows a schematic representation of an embodiment of the control device for at least one electric motor of an on-board brake system.

The control device 10 Can with a variety of engine types of an electric motor 12 interacting with an on-board brake system. For example, the control device 10 in one of the brake systems of DE 10 2012 211 278 A1 , of the DE 10 2012 222 974 A1 or the DE 10 2012 222 978 A1 be used.

The control device 10 has an electronics device 14 , which is designed to at least one target size with respect to one of the electric motor 12 Set (to at least one wheel of the vehicle equipped with the braking system and / or at least one axis of the vehicle) to be effected target engine braking torque. The determination of the at least one desired value takes place, for example, taking into account at least one provided brake specification signal 16 with respect to a requested vehicle deceleration requested by a driver of the vehicle. Alternatively, the electronic device 14 also be designed to the at least one target size, taking into account at least one provided engine command signal 18 with respect to (from another vehicle component 20 ) determined in consideration of the requested target vehicle deceleration and by means of the electric motor 12 to set the required engine deceleration. It is expressly pointed out here that the electronic device is designed to provide the at least one desired value taking into account the at least one provided brake specification signal 16 or the at least one provided engine command signal 18 and with the additional consideration of a (on a storage unit 22 ) stored characteristic k.

Subsequently, the electronics device 14 adapted to a motor control signal corresponding to the at least one desired size 24 to the electric motor 12 to output so that by means of the motor control signal 24 controlled electric motor 12 a the actual engine braking torque corresponding to the target engine braking torque on the at least one wheel and / or the at least one axis is effected / is effected.

The electronic device 14 is additionally designed to provide the characteristic k considering at least one current piece of information 26 to 30 with respect to at least one clearance of at least one wheel brake cylinder of the brake system and / or at least one volume-pressure relation of at least one brake circuit of the brake system reposition and (as a newly established characteristic kc on the memory unit 22 ) store. In the embodiment of the 3 is the electronic device 14 For example, designed to the characteristic k considering at least one provided lateral acceleration 26 the vehicle during a time interval after a last brake pressure build-up in the at least one wheel brake cylinder as the at least one current information 26 re-set and save with respect to the at least one clearance of the at least one wheel brake cylinder. Alternatively, the electronic device 14 also be designed for determining / measuring the at least one lateral acceleration. Of Furthermore, a brakeless travel time after the last brake pressure build-up in the at least one wheel brake cylinder can also be taken into account for the redefinition of the characteristic k.

Advantageously, the electronic device 14 Also designed to the characteristic k taking into account a self-determined or provided delay difference 28 which in a transition of the brake system from a first operating mode of the brake system (pure recuperative braking mode), in which a previously requested target vehicle deceleration is first satisfied solely by means of the electric motor, in a second operating mode of the brake system (pure-hydraulic braking mode), in which the previously requested target vehicle deceleration is later fulfilled exclusively by means of the at least one wheel brake cylinder, occurs as the at least one current information 28 re-set and save with respect to the at least one volume-pressure relation of the at least one brake circuit. Likewise, the electronic device 14 be designed to the characteristic k taking into account a relation 30 between an increase in time of an adjustment path of at least one brake actuation element displaced by the driver in a previous request for a target vehicle deceleration and an increase in time of at least one brake pressure in the at least one wheel brake cylinder (during the purely hydraulic braking mode) as the at least one actual information 30 re-set and save with respect to the at least one volume-pressure relation of the at least one brake circuit.

The control device 10 meets all the advantages listed above. It can be designed to carry out all of the method steps described above. The further effect also an electric motor 12 for an on-board brake system with such a control device 10 or a braking system for a vehicle with a corresponding control device 10 the above advantages.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The 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

• DE 102012211278 A1 [0002, 0014, 0015, 0026, 0043, 0045]
• DE 102012222974 A1 [0002, 0014, 0015, 0026, 0043, 0045]
• DE 102012222978 A1 [0002, 0014, 0015, 0026, 0043, 0045]

Claims (10)

Method for operating an on-board brake system with an electric motor ( 12 ) comprising the steps of: determining at least one brake specification quantity (s) with respect to a desired vehicle deceleration of the vehicle requested by a driver of a vehicle equipped with the brake system; and executing the requested target vehicle deceleration at least temporarily using the electric motor ( 12 ) by - at least one desired quantity with respect to one of the electric motor ( 12 ) is set to at least one wheel of the vehicle and / or at least one axis of the vehicle to be effected target engine braking torque taking into account a predetermined or specified characteristic (k) and the at least one brake default size (s); and - the electric motor ( 12 ) is controlled such that the requested target vehicle deceleration is carried out at least partially by means of an actual engine braking torque (Mm) which corresponds to the desired engine braking torque and is effected on the at least one wheel and / or the at least one axle; characterized by the step: setting (P) of the characteristic curve (k) at least once taking into account at least one current information (I1, I2, 26 to 30 ) with respect to at least one clearance of at least one wheel brake cylinder of the brake system and / or at least one volume-pressure relation of at least one brake circuit of the brake system. The method of claim 1, wherein as the at least one up-to-date information ( 26 ) with respect to the at least one clearance of the at least one wheel brake cylinder at least one transverse acceleration ( 26 ) of the vehicle during a time interval after a last brake pressure build-up in the at least one wheel brake cylinder is determined. Method according to claim 1 or 2, wherein as the at least one up-to-date information (I1, 28 ) with respect to the at least one volume-pressure relation of the at least one brake circuit an occurring delay difference (I1, 28 ), Pressure difference and / or braking torque difference at a transition of the brake system from a first operating mode of the brake system, in which a previously requested target vehicle deceleration at first exclusively or partially by means of the electric motor ( 12 ) is satisfied, in a second operating mode of the brake system, in which the previously requested target vehicle deceleration is later met only by means of the at least one wheel brake cylinder, is determined. Method according to one of the preceding claims, wherein as the at least one current information (I2, 30 ) with respect to the at least one volume-pressure relation of the at least one brake circuit a relation (I2, 30 ) between an increase in time of a Verstellwegs (s) at least one of the driver in a previous request for a desired vehicle deceleration adjusted brake actuator and an increase in time of at least one brake pressure in the at least one wheel brake cylinder is determined. Control device ( 10 ) for at least one electric motor ( 12 ) an on-board brake system comprising: an electronic device ( 14 ), which is designed taking into account at least one provided brake specification signal ( 16 ) with respect to a desired vehicle deceleration requested by a driver of the vehicle equipped with the brake system or at least one provided engine specification signal ( 18 ) with reference to the requested target vehicle deceleration and by means of the electric motor ( 12 ) to be effected desired engine deceleration at least one target size with respect to one of the electric motor ( 12 ) to set at least one wheel of the vehicle and / or at least one axis of the vehicle to be effected target engine braking torque and one of the at least one desired size corresponding engine control signal ( 24 ) to the electric motor ( 12 ) so that by means of the motor control signal ( 24 ) controlled electric motor ( 12 ) an actual engine braking torque (Mm) corresponding to the desired engine braking torque can be transmitted to the at least one wheel and / or the at least one axle, wherein the electronic device ( 14 ) is designed, the at least one target size taking into account the at least one provided brake command signal ( 16 ) or the at least one provided engine command signal ( 18 ) and with additional consideration of a stored characteristic curve (k); characterized in that the electronic device ( 14 ) is designed in addition to the characteristic (k) taking into account at least one current information (I1, I2, 26 to 30 ) to set and store at least one clearance of at least one wheel brake cylinder of the brake system and / or at least one volume-pressure relation of at least one brake circuit of the brake system. Control device ( 10 ) according to claim 5, wherein the electronic device ( 14 ) is designed, the characteristic curve (k) taking into account at least one self-mediated or provided lateral acceleration ( 26 ) of the vehicle during a time interval after a last brake pressure build-up in the at least one wheel brake cylinder as the at least one current information ( 26 ) re-set and save with respect to the at least one clearance of the at least one wheel brake cylinder. Control device ( 10 ) according to claim 5 or 6, wherein the electronic device ( 14 ) is designed, the characteristic curve (k) taking into account a self-determined or provided delay difference (I1, 28 ), which at a transition of the brake system from a first operating mode of the brake system, in which a previously requested target vehicle deceleration first exclusively by means of the electric motor ( 12 ) is met, in a second operating mode of the brake system, in which the previously requested target vehicle deceleration is later met only by means of the at least one wheel brake cylinder occurs, as the at least one current information (I1, 28 ) to set and store with respect to the at least one volume-pressure relation of the at least one brake circuit. Control device ( 10 ) according to one of claims 5 to 7, wherein the electronic device ( 14 ) is designed to change the characteristic curve (k) taking into account a relation (I2, 30 ) between a time increase of an adjustment path (s) of at least one brake actuation element displaced by the driver in an earlier request of a target vehicle deceleration and an increase in time of at least one brake pressure in the at least one wheel brake cylinder as the at least one current information (I2, 30 ) to set and store with respect to the at least one volume-pressure relation of the at least one brake circuit. Electric motor ( 12 ) for an on-board brake system with a control device ( 10 ) according to any one of claims 5 to 8. Brake system for a vehicle with a control device ( 10 ) according to one of claims 5 to 8 or an electric motor ( 12 ) according to claim 9.

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