WO2020020757A1

WO2020020757A1 - Control apparatus and method for operating a brake system of a vehicle

Info

Publication number: WO2020020757A1
Application number: PCT/EP2019/069457
Authority: WO
Inventors: Marcus BUCHER; Yasutaka NAGAKURA
Original assignee: Robert Bosch Gmbh
Priority date: 2018-07-24
Filing date: 2019-07-18
Publication date: 2020-01-30
Also published as: CN112424038A; CN112424038B; DE102018212276A1

Abstract

The invention relates to a control apparatus (50) for at least one pump (26) of a brake system of a vehicle having an electronic device (52), which is designed to determine at least one set point value in respect of a set point speed of at least one pump (26), and to control (S2) the at least one pump (26) according to the determined set point value such that brake fluid can be pumped from at least one storage chamber (20, 30), hydraulically connected to the respective pump (26) on the intake side, into the at least one wheel brake cylinder (16) such that at least one brake pressure in the at least one wheel brake cylinder (16) can be increased, wherein the electronic device (16) is additionally designed to re-determine (S0) a respective pressure-volume relation (V_(P)) of at least one brake circuit, comprising the at least one pump (26), of the brake system, and to determine the at least one set point value under additional consideration of the re-determined pressure-volume relation (V(P)) of at least the brake circuit comprising the respective pump (26). The invention further relates to a method for operating a brake system of a vehicle.

Description

description

title

Control device and method for operating a braking system

vehicle

The invention relates to a control device for at least one pump of a brake system of a vehicle and a brake system for a vehicle. Furthermore, the invention relates to a method for operating a brake system of a vehicle.

State of the art

DE 10 2012 222 974 A1 describes a method for operating a brake system of a vehicle and a correspondingly designed one

Control device. When the method is carried out, a desired vehicle deceleration requested by a driver of the vehicle is preferably effected exclusively by means of a generator operation of an electric motor of the vehicle. In order to use only the

regenerative operation of the electric motor caused braking of the

To limit or prevent an undesired build-up of brake pressure in a vehicle in at least one wheel brake cylinder of the brake system, the driver presses it out of a master brake cylinder of the brake system when requesting the desired vehicle deceleration

Brake fluid volume shifted into at least one storage chamber by opening at least one valve. As soon as the requested target vehicle deceleration can no longer be achieved solely by the generator operation of the electric motor, the brake fluid volume shifted into the at least one storage chamber is at least partially pumped into at least one of the wheel brake cylinders by means of at least one pump of the brake system. Disclosure of the invention

The invention provides a control device for at least one pump of a brake system of a vehicle with the features of claim 1, a brake system for a vehicle with the features of claim 6 and a method for operating a brake system of a vehicle with the features of claim 7.

Advantages of the invention

The present invention provides easily implementable options for adapting an operation of at least one pump of a brake system of a vehicle to at least one current hydraulic rigidity of at least one brake circuit of the brake system comprising the at least one pump. The present invention likewise effects an adaptation of the operation of the at least one pump to at least one air gap at least in the brake circuit comprising the at least one pump. The present invention ensures that even if there is a significant deviation of the at least one current hydraulic stiffness from its standard value and / or at least a pronounced air gap by means of the operation of the at least one pump adapted using the present invention, at least one to realize the brake pressure increase to be brought about The amount of brake fluid required for a wheel brake cylinder is reliably pumped into the at least one wheel brake cylinder. A desired vehicle deceleration of the vehicle requested by a driver of the vehicle and / or an automatic speed control device of the vehicle can thus be brought about in such a way that the driver does not have any (perceptible / perceptible)

Delay deviations or delay fluctuations noticed. The present invention thus contributes to improving braking comfort on the respective vehicle.

From the start-up of a brake system, when controlling its at least one pump, only a ratio between one in at least one brake circuit comprising the at least one pump becomes conventional the pressure of the brake system is assumed at a (simultaneously) present brake fluid volume equal to a predetermined standard relation. However, production deviations can affect the hydraulic rigidity of the braking system. The hydraulic

Rigidity often changes even after the brake system has been started up. In particular, aging effects and / or a temperature can increase

ongoing changes to the hydraulic rigidity of the lead. However, the present invention brings about an advantageous "correction" of

Production deviations, temperature fluctuations and / or

Aging effects, or their effects on the hydraulic rigidity of the braking system.

In an advantageous embodiment of the control device

Electronic device designed to at least once the respective pressure-volume relationship of the brake circuit of the brake system comprising the at least one pump, taking into account at least one pressure variable provided to the electronic device with respect to a

To redetermine the master brake cylinder pressure in a master brake cylinder of the brake system and at least one adjustment path variable provided to the electronic device with respect to an adjustment path of at least one adjustable piston of the master brake cylinder. In particular, an evaluation of the at least one pressure variable together with the at least one adjustment path variable can be used to reliably determine whether a previously determined pressure-volume ratio still corresponds to the current hydraulic rigidity of at least the brake circuit comprising the respective pump. A subsequent redefinition of the pressure-volume relationship can thus ensure that it is adapted to the current hydraulic rigidity again as required.

In a further advantageous embodiment of the control device, the electronic device is designed to take into account at least one of the electronic devices, which is predetermined or at least

Specified target motor deceleration variable with respect to a target motor deceleration to be brought about by means of at least one electric motor, and at least one target operating variable of the respective electric motor, and to control the at least one electric motor in accordance with at least its specified target operating variable such that the vehicle can be braked by means of a generator operation of the at least one electric motor with an actual engine deceleration caused by the at least one electric motor and corresponding to at least its specified target operating variable. The embodiment of the control device described here can thus also be used for recuperative braking of the vehicle.

As an advantageous development of the control device, the

Electronics device can also be designed to determine the at least one target operating variable with additional consideration of the newly determined pressure-volume ratio. As will be explained in more detail below, this embodiment of the control device also excites the driver during one

Braking, the requested target vehicle deceleration is effected exclusively by the generator operation of the at least one electric motor, to adapt its requirement of the target vehicle deceleration to the current hydraulic rigidity and / or to the at least one air gap.

The electronic device is preferably additionally designed to take into account the at least one target pressure difference variable with respect to the brake pressure increase to be brought about in the at least one wheel brake cylinder and / or the at least one target motor deceleration variable with regard to the target motor deceleration to be brought about by means of the at least one electric motor, taking into account at least one Brake target size with respect to one of a driver of the vehicle or an automatic one

Speed control device to set requested target vehicle deceleration of the vehicle. The control device is thus versatile.

In addition, the control device can also be used for autonomous or semi-autonomous driving of the vehicle.

The advantages described above are also ensured in a brake system for a vehicle with such a control device, the at least one pump which can be controlled by means of the control device and the at least one on the delivery side on the at least one pump hydraulically connected wheel brake cylinder and the at least one storage chamber hydraulically connected on the suction side to the at least one pump.

Furthermore, executing a corresponding method for operating a brake system of a vehicle also creates the advantages described above. It is expressly pointed out that the method for operating a brake system of a vehicle can be further developed in accordance with the above-described embodiments of the control device.

Brief description of the drawings

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

Fig. La to lc a flow chart, a calculation scheme and a

Coordinate system for explaining a first embodiment of the method for operating a brake system of a vehicle;

2a and 2b are schematic partial representations of a brake system for

Explain a second embodiment of the method for operating a brake system of a vehicle; and

Fig. 3 is a schematic representation of an embodiment of the

Control device for at least one pump of a brake system of a vehicle.

Embodiments of the invention

La to lc show a flowchart, a calculation scheme and a

Coordinate system for explaining a first embodiment of the method for operating a brake system of a vehicle. The method described below cannot be carried out either on a specific brake system type of the brake system or on a special vehicle type / motor vehicle type of the one equipped with the brake system

Vehicle / motor vehicle limited.

The method has a method step S1, which is preferably carried out whenever at least one brake pressure in at least one wheel brake cylinder of the brake system hydraulically connected to at least one pump is to be increased by means of the at least one pump. For this purpose, at least one target variable with respect to a respective target speed of the at least one pump is defined in method step S1. The at least one target size can e.g. the desired target speed of the at least one pump and / or a target current of a current output to at least one pump motor of the at least one pump. However, the examples given here for the at least one target variable are not to be interpreted conclusively. The at least one target variable is set in method step S1 at least under

Taking into account a brake pressure increase to be brought about in the at least one wheel brake cylinder.

The method described here also has a method step SO in which a respective pressure-volume relationship of at least one brake circuit of the brake system comprising the at least one pump is newly determined. The pressure-volume relation is to be understood as a relation which represents a relationship between a pressure p present in at least the brake circuit of the brake system comprising the at least one pump at a (simultaneously) brake fluid volume V present therein. The pressure-volume relationship can include at least one pressure-volume factor or be a pressure-volume characteristic. The ratio between the pressure p present in at least the brake circuit of the brake system comprising the at least one pump and (simultaneously) therein

present brake fluid volume V is often referred to as hydraulic rigidity. When the brake system is started up, a ratio between the brake circuit of the brake system comprising at least one pump is conventionally used existing pressure p and the (simultaneously) present brake fluid volume V are equal to a predetermined standard relation. However, the actual relationship between the pressure p present in at least the brake circuit of the brake system comprising the at least one pump and the (simultaneously) therein

present brake fluid volume V, e.g. owing to

Production deviations, temperature influences and / or aging effects, deviate from the standard relation. Using method step SO, the pressure-volume relation can be redetermined, possibly deviating from the standard relation. Method step SO is carried out at least once during operation of the brake system. Method step SO is preferred during the operation of the brake system

repeated periodically / regularly. Advantageous options for executing method step SO are described below.

After the at least one execution of the method step SO, when the at least one brake pressure in the at least one wheel brake cylinder is subsequently increased by means of the at least one pump when the method step S1 is carried out, the at least one target variable is at least taken into account, taking into account the newly determined pressure-volume ratio of the brake circuit comprising the respective pump. Thus, not only the one to be effected in the at least one wheel brake cylinder

Brake pressure increase, but also the newly determined pressure-volume ratio of at least the brake circuit comprising the respective pump when determining the at least one target variable. If the newly determined pressure-volume relation indicates that, in comparison with the standard relation, a larger brake fluid volume V is required to effect a certain pressure p, the at least one target variable corresponding to a target speed of the at least increased compared to the standard relation set a pump. Accordingly, it is advantageous if, insofar as the newly determined pressure-volume relation indicates that, in comparison with the standard relation, only a smaller brake fluid volume V is required to effect a certain pressure p, which reduced at least one target quantity corresponding to one compared to the standard relation Target speed of the at least one pump is determined. In a method step S2 carried out after method step S1, the at least one pump is controlled in accordance with its specified target size in such a way that the at least one pump with an actual rotational speed corresponding to its target size from at least one brake fluid

hydraulically connected to the respective pump on the suction side

Storage chamber pumps into the at least one wheel brake cylinder. The at least one brake pressure in the at least one wheel brake cylinder of the brake system hydraulically connected to the at least one pump on the delivery side is increased in this way by means of the at least one pump. The at least one storage chamber hydraulically connected on the suction side to the respective pump can e.g. at least one

Low pressure storage chamber and / or a brake fluid reservoir.

If, due to a change in the hydraulic stiffness compared to the standard relation, a larger volume of brake fluid V is required to effect a certain pressure p, taking the newly determined pressure-volume relation into account when driving the at least one pump will result in an advantageous acceleration of the actual rotation rate of the at least one pump. Thus, despite the change in hydraulic rigidity, enough brake fluid is pumped by means of the at least one pump. Accordingly, if, due to a change in the hydraulic rigidity compared to the standard relation, a smaller volume of brake fluid V is sufficient to effect a certain pressure p, the fact that the newly determined pressure-volume relation is taken into account when the at least one pump is actuated reduces the actual Rotation rate of at least one pump reached. This ensures that despite the change in hydraulic rigidity, not too much brake fluid is pumped by means of the at least one pump.

The method described here brings about an adaptation of the operation of the at least one pump to the actually existing ratio between the pressure p present in at least the brake circuit of the brake system comprising the at least one pump and the (simultaneously) therein

available brake fluid volume V, or to the current hydraulic rigidity of the brake system. When executing the described here The actual rotation rate of the at least one pump is adjusted in such a way that, despite a possible change in the hydraulic rigidity of the brake system, this leads to the effect of the respective target pressure (as brake pressure) in the

at least one wheel brake cylinder of the brake system to be pumped

Brake fluid volume is reliably pumped by means of the at least one pump, but is not exceeded. Too little deceleration of the vehicle due to pumping too little brake fluid into the at least one wheel brake cylinder, excessive braking of the vehicle due to pumping too much brake fluid into the at least one wheel brake cylinder, or fluctuations in deceleration are therefore hardly possible when the method described here is carried out fear.

Conventional pump controls generally only take into account the standard relation when controlling the at least one pump. Therefore, pump controls according to the prior art often cause either an insufficient brake pressure increase if, in comparison with the standard relation, a larger brake fluid volume V is required to produce a certain pressure p, or an excessive brake pressure increase, if a smaller one compared to the standard relation

Brake fluid volume V is sufficient to cause a certain pressure p. The method described here overcomes this disadvantage of conventional pump controls and thus reduces a frequency of deviations between the target pressure desired in the at least one wheel brake cylinder and the brake pressure actually caused therein compared to the prior art. In this way, the method described here creates an advantageous “correction” of production deviations, temperature fluctuations and / or aging effects, or of their effects

Effects on the hydraulic rigidity of the braking system.

The respective pressure-volume ratio of at least the brake circuit of the brake system comprising the at least one pump can be at least once, taking into account at least one determined pressure variable P _MC with respect to a master brake cylinder pressure P _MC in a master brake cylinder of the brake system and at least one determined displacement path variable SMC with respect to an adjustment path SMC at least one adjustable piston of the master brake cylinder can be redetermined. This is shown by way of example using the calculation scheme in FIG. 1b.

The at least one print variable P _MC is, for example, the

Master cylinder pressure PMC, or a pre-pressure corresponding to the master cylinder pressure PMC, which is determined by means of a pressure sensor connected to the master cylinder, is evaluated. The at least one adjustment path size SMC is the adjustment path SMC of the rod piston of the

Master brake cylinder, or the adjustment path of an output piston arranged upstream of the rod piston, which is determined, for example, by means of a rod displacement sensor and / or a differential displacement sensor. A normal pressure p _n0 rmai is derived from a predetermined characteristic curve on the basis of the at least one adjustment _path variable SMC. By means of a difference between the normal pressure p _n0 rmai and the master brake cylinder pressure P _MC and a difference between a time derivative of the normal pressure p _n0 rmai and a time derivative of the master brake cylinder pressure P _MC , the pressure-volume pressure is, as shown schematically in FIG. Relation redetermined.

In the coordinate system of FIG. 1c, an abscissa indicates a pressure p (in bar) present in at least one partial volume of the braking system, while an abscissa indicates a pressure p in at least the partial volume of the

Brake system present brake fluid volume V of the brake system (in milliliters) is reproduced. A pressure-volume relation V (p) is shown in the coordinate system of FIG. 1c. As is also shown in the coordinate system of FIG. 1c, a pressure-volume factor k can be derived from the pressure-volume relation V (p) for small pressure differences. The following applies to the pressure values p of the pressure-volume relation V (p) according to equation (Eq. 1):

(Eq. 1) p = a * V * k where a is a gradient of the pressure-volume relation V (p) at a certain point. The same applies to the volume values of the pressure-volume relation V (p) equation (Eq. 2) with:

(Eq. 2) V = - One to realize a desired front wheel target pressure PF _A (as

Brake pressure) in the wheel brake cylinders of a front axle of the

Vehicle / motor vehicle and a desired rear wheel target pressure PR _A (as brake pressure) in the wheel brake cylinders of a rear axle of the

Vehicle / motor vehicle by means of the setpoint volume flow q _pU mp to be brought about by means of the at least one pump can thus in method step S1 according to

Equation (Eq. 3) can be determined with:

where (in bar / milliliter) is a constant / stiffness of the wheel brake cylinder of the front axle, CR _A (in bar / milliliter) is a constant / stiffness of the wheel brake cylinder of the rear axle and q _{driver is} one that the driver simultaneously removes from the

Master brake cylinder volume flow is pushed out. The volume flow q _driver simultaneously pushed out of the master brake cylinder by the _driver results from the equation (Eq. 4) with:

where dMc is a diameter of the master brake cylinder and SMC is the adjustment path of the at least one adjustable piston of the master brake cylinder.

For comparison, a state of the art known internally to the applicant is also represented by means of an equation (Eq. 5), in which the setpoint size of the at least one pump is based on the setpoint volume flow q _P ump- _P determined according to equation (Eq. 5) rior-art is determined:

2a and 2b show schematic partial representations of a brake system for explaining a second embodiment of the method for operating a brake system of a vehicle. The method schematically reproduced with the aid of FIGS. 2a and 2b is a further development of the previously described embodiment. Thus, even when the brake system shown in FIGS. 2a and 2b is operated, the pressure-volume relationship is redetermined at least once.

When the method described below is carried out, when a brake actuation element / brake pedal 10 is actuated by a driver of the vehicle, at least one braking specification variable is determined with respect to a target vehicle deceleration of the vehicle requested by the driver. In particular, an adjustment path of the brake actuation element / brake pedal 10, an adjustment path of a driver brake force transmission component connected to the brake actuation element / brake pedal and / or a driver brake force 12 exerted by the driver on the brake actuation element / brake pedal 10 can be determined as the at least one brake specification variable. At least one brake actuation element sensor 14, such as, for example, a brake pedal travel sensor, a rod travel sensor, a differential travel sensor and / or a driver brake force sensor, can be used to determine the at least one brake specification variable. Alternatively, the at least one brake specification variable can also be from an automatic one

Speed control device may be issued.

The requested target vehicle deceleration is carried out at least temporarily using at least one electric motor (not shown). The at least one electric motor can be understood to mean an (electric) motor which, by means of its generator operation, is used for

Braking the vehicle converts a kinetic energy of the vehicle into electrical energy and stores it in at least one storage unit / battery. For example, the at least one electric motor can also be a drive motor for (optionally) accelerating the vehicle. However, it is pointed out that the method described here cannot be carried out for a specific engine type of the at least one

Electric motor is limited.

The generator operation of the at least one electric motor for

Braking the vehicle has the advantage that the kinetic energy of the Vehicle after conversion into electrical energy can be used later if necessary. The effect of the requested target vehicle deceleration at least temporarily using the at least one electric motor thus reduces the vehicle's energy consumption and possibly also pollutant emissions during a journey. The requested target vehicle deceleration is preferably carried out as often as possible exclusively by means of the at least one electric motor, in order in this way to obtain as much electrical energy as possible. This is also referred to as operating the brake system in its purely recuperative braking mode, in which the requested target vehicle deceleration is (essentially) effected exclusively by means of the at least one electric motor.

However, the at least one electric motor can only be used to brake the vehicle if the at least one storage unit / battery is not yet fully charged and the vehicle is at a speed of at least one for operating the at least one as a generator

Electric motor necessary minimum speed runs. For this reason, the brake system is often also operated in its purely hydraulic brake mode, in which the requested target vehicle deceleration is (essentially) effected only by means of at least one wheel brake cylinder 16a and 16b of the brake system.

Fig. 2a shows the braking system in a situation at the beginning of a braking of the vehicle, the requested target vehicle deceleration, since the

at least one storage unit / battery is not fully charged and / or the speed of the vehicle is above that required to operate the at least one electric motor as a generator

Minimum speed is, by means of the purely recuperative braking mode. Taking into account the at least one braking specification variable, at least one target motor deceleration to be brought about by means of the at least one electric motor is determined (in total) equal to the requested target vehicle deceleration. In addition, a brake pressure increase to be brought about in the at least one wheel brake cylinder 16a and 16b is set to (almost) zero. In order to increase the respective brake pressure in the at least one wheel brake cylinder 16a and 16b of the brake system to (almost) zero despite the driver's actuation of the brake actuation element / brake pedal 10, in which brake fluid is pressed out of a master brake cylinder 18 of the brake system by means of the driver's braking force 12 limit, a volume of brake fluid pushed out of the master brake cylinder 18 of the brake system into at least one storage chamber 20 of the

Brake system shifted. This process is often called a

Called "blending". As an example, the volume of brake fluid pressed out of the master brake cylinder 18 of the brake system is shifted via at least one open wheel inlet valve 22 and at least one open wheel outlet valve 24 into at least one low-pressure storage chamber 20 of the brake system. As shown in Fig. 2a, at least one of the

Wheel intake valves 22 during the shifting of the

Master brake cylinder 18 of the brake system pushed out

Brake fluid volume can also be kept closed. The

Wheel brake cylinders 16a and 16b of the brake system thus exert almost no braking effect during the purely recuperative braking mode.

To brake the vehicle by means of the at least one electric motor, at least one desired operating variable of the respective electric motor is under

Taking into account the at least one target engine deceleration set.

In addition, at least the target operating variable is determined taking into account the newly determined pressure-volume ratio, for example the pressure-volume factor k. The at least one electric motor is then controlled in accordance with at least its specified target operating variable in such a way that by means of generator operation of the at least one electric motor, the vehicle is operated with one of the

effect at least one electric motor and is braked at least according to its specified target operating variable actual motor deceleration.

The at least one redetermination of the pressure-volume ratio, for example the pressure-volume factor k, and the determination of at least the desired operating variable with additional consideration of the newly determined pressure-volume ratio, the generator operation of the at least one Electric motor to the often deviating from a standard relation

adjusted hydraulic rigidity of the braking system. The driver thus becomes larger when compared to the standard relation

Brake fluid volume V is required to bring about a certain pressure p, to press out more brake fluid from the master brake cylinder 18 to effect the desired vehicle deceleration requested by it.

The driver becomes corresponding if, in comparison with the standard relation, a smaller brake fluid volume V for causing one

certain pressure p is sufficient to effect the desired vehicle deceleration requested less brake fluid from the

Push out master brake cylinder 18. That in the at least one

Storage chamber 20 displaced brake fluid volume thus corresponds to an amount adapted to the current hydraulic rigidity

Brake fluid which is used to effect the desired vehicle deceleration requested by the driver by means of the purely hydraulic braking mode

Wheel brake cylinders 16a and 16b would be transferred.

2b shows the braking system from a point in time at which the desired vehicle deceleration requested by the driver can no longer be effected exclusively by means of the at least one electric motor. Therefore, the at least one electric motor is "shut down" and at the same time by means of at least one pump 26 brake fluid from the at least one

Storage chamber 20 pumped into the wheel brake cylinders 16a and 16b. The

Activation of at least one pump motor 28 of the at least one pump 26 takes place in accordance with the method of FIG. 1 explained above. This ensures that a respective actual speed of rotation of the at least one pump 26 corresponds to the current hydraulic rigidity of the brake system. The one in the

Wheel brake cylinders 16a and 16b desired target pressure can thus be achieved reliably and without delay fluctuations by means of the at least one pump 26. Since this also in the at least one storage chamber 20th

displaced brake fluid volume corresponds to the amount of brake fluid required to effect the requested target vehicle deceleration by means of the purely hydraulic brake mode in the wheel brake cylinders 16a and 16b, no additional brake fluid has to be supplied / sniffed during the operation of the at least one pump 26. Moreover As a rule, no unnecessary brake fluid has to be transferred from the at least one storage chamber 20 into a brake fluid reservoir 30 of the brake system after braking.

As soon as the requested target vehicle deceleration is achieved exclusively by means of the wheel brake cylinders 16a and 16b, the at least one pump 26 can be stopped and the at least one electric motor can be deactivated. From this point in time it can optionally be checked whether the transition of the braking system from its purely recuperative braking mode to its purely hydraulic braking mode is a (not requested by the driver)

Has caused deceleration difference on the vehicle. Sensors for determining the possible braking system occurring during the transition from its purely recuperative braking mode to its purely hydraulic braking mode

Delay differences are conventionally already installed on a vehicle. Also based on the occurrence of a deceleration difference (not equal to zero) when the brake system changes from its purely recuperative one

Braking mode in its purely hydraulic braking mode, it can be seen that the hydraulic rigidity of the braking system has changed and therefore it is advantageous to redetermine the pressure-volume ratio. Then, possibly using at least one pressure sensor / pre-pressure sensor 32 of the brake system, the pressure-volume relationship can be updated.

The advantageous activation of the at least one pump 26 below

Taking into account the current hydraulic rigidity of the brake system, it is ensured that the deceleration difference that may occur, or at least one, by means of the at least one pressure sensor / admission pressure sensor 32

determined pressure deviation, is not due to an “insufficient control” of the respective pump 26. Instead, due to the

Activation of the at least one pump 26, taking into account the newly determined pressure-volume ratio or the newly determined pressure-volume factor k, is based on an operation of the at least one pump 26 that is adapted to the current hydraulic rigidity. The method described here thus offers "protection" from an incorrect interpretation of a change in the current hydraulic stiffness of the braking system delay difference to be attributed as a result of an “insufficient activation” of the respective pump 26.

A vacuum brake booster 34, a high-pressure switching valve 36, are also optional elements of the brake system in FIGS. 2a and 2b

Switch valve 38 and a filter 40 shown.

Fig. 3 shows a schematic representation of an embodiment of the

Control device for at least one pump of a brake system of a vehicle.

The control device 50 shown schematically in FIG. 3 has one

Electronic device 52, which is designed, at least taking into account at least one setpoint pressure difference variable with respect to a brake pressure increase to be brought about in each case on at least one wheel brake cylinder hydraulically connected to the at least one pump 26, at least one setpoint quantity with respect to a respective setpoint speed of the at least one Determine pump 26. The at least one setpoint pressure difference variable can be specified for the electronic device 52 by an external control, such as an automatic speed control, or it can be defined by the electronic device 52. The

Electronics device 52 is additionally designed to redetermine at least once a respective pressure-volume relationship of at least one brake circuit of the brake system comprising the at least one pump 26, and the at least one target variable, taking into account at least the newly determined pressure-volume relationship determine the respective pump 26 comprising the brake circuit. In addition, the electronic device 52 is designed to control the at least one pump 26 by means of at least one pump control signal 54 in accordance with the specified target size in such a way that it operates using one of its target values

corresponding actual speed of the at least one controlled pump 26 brake fluid from at least one storage chamber hydraulically connected on the suction side to the respective pump 26 into the at least one

Wheel brake cylinder is pumpable / is pumped. In this way, there is / will be at least one brake pressure in the at least one wheel brake cylinder be increased / improved. The control device 50 described here thus also brings about the advantages already explained above.

As an advantageous further development, the electronic device 52 is

Control device 50 of FIG. 3 also designed, at least under

Taking into account at least one target motor deceleration variable with respect to a target motor deceleration to be brought about by means of at least one electric motor 56, at least one target operating variable of the respective one

Set electric motor 56. The at least one setpoint motor deceleration variable can also be predetermined for the electronic device 52 by the external controller or specified by the electronic device 52. In addition, the electronic device 52 is designed to determine the at least one target operating variable with additional consideration of the newly determined pressure-volume ratio, and then to control the at least one electric motor 56 in accordance with at least its predetermined target operating variable by means of at least one motor control signal 58 such that by means of a generator operation of the at least one electric motor 56, the vehicle can be braked / braked with an actual engine deceleration caused by the at least one electric motor 56 and corresponding to at least its specified target operating variable. The control device can thus carry out all of the method steps described above.

Advantageously, the electronic device 52 is additionally designed to take into account the at least one setpoint pressure difference variable with regard to the increase in brake pressure to be effected in the at least one wheel brake cylinder and / or the at least one setpoint motor deceleration variable with respect to the setpoint motor deceleration to be effected by means of the respective electric motor 56 to determine at least one braking specification variable 60 with respect to a target vehicle deceleration of the vehicle requested by a driver of the vehicle. To provide the at least one

Brake specification size 60 suitable sensor systems have already been mentioned above.

The electronic device 52 can determine the respective pressure-volume relationship of at least the brake circuit of the brake system comprising the at least one pump 26, for example taking into account at least one of the brake systems Electronics device 52 provided print size 62 with respect to a

Master cylinder pressure in a master cylinder of the brake system and at least one provided to the electronic device 52

Adjustment path size 64 with respect to an adjustment path at least one

Redetermine the adjustable piston of the master brake cylinder. Also when the brake system changes from a purely recuperative braking mode, in which the requested target vehicle deceleration is effected exclusively by means of the at least one electric motor 56, to a purely hydraulic braking mode, in which the requested target vehicle deceleration is effected only by means of the at least one Wheel brake cylinder of the brake system is effected, occurring deceleration difference can be evaluated by means of the electronic device 52 to redefine the pressure-volume relationship. By advantageously controlling the at least one pump 26 by means of the

Electronic device 52 taking into account the current hydraulic rigidity of the braking system is a

Occurrence of a delay difference due to the pumping of an excessive amount of brake fluid, although in comparison with the standard relation a smaller volume of brake fluid V would be sufficient to produce a certain pressure p, or an insufficient amount of brake fluid, although a larger amount compared to the standard relation

Brake fluid volume V would be necessary to effect a certain pressure p prevented. A detected deceleration difference can thus be correctly interpreted as a change in the hydraulic rigidity of the brake system. There is no need to fear “learning” the wrong hydraulic stiffness of the braking system.

The advantages described above are also in a brake system for a vehicle with the control device 50, the at least one pump 26 which can be controlled by means of the control device 50, the at least one wheel brake cylinder hydraulically connected on the delivery side to the at least one pump 26 and the at least one on the suction side of the at least one Pump 26 hydraulically connected storage chamber guaranteed.

The usability of the control device 50 described above is not applicable to a specific brake system type of the brake system or to a specific one Vehicle type / vehicle type of the vehicle / motor vehicle equipped with the braking system is restricted.

Claims

Expectations

1. Control device (50) for at least one pump (26) of a brake system of a vehicle, comprising: an electronic device (52) which is designed to take into account at least one of the electronic devices (52) or specified by the electronic device (52) Desired pressure difference quantity with respect to one that is hydraulically connected on at least one pump (26) on the delivery side

Wheel brake cylinder (16a, 16b) to be effected in each case

Determine brake pressure increase at least one target value with respect to a respective target speed of the at least one pump (26), and to control the at least one pump (26) in accordance with the specified target size in such a way that by means of an operation corresponding to its target size The speed of the at least one controlled pump (26) brake fluid can be pumped from at least one storage chamber (20) hydraulically connected on the suction side to the respective pump into the at least one wheel brake cylinder (16a, 16b) such that at least one brake pressure in the at least one wheel brake cylinder (16a , 16b) can be increased; characterized in that the electronic device (52) is additionally designed to redetermine at least once a respective pressure-volume relationship of at least one brake circuit of the brake system comprising the at least one pump (26), and the at least one target variable with additional consideration to determine the newly determined pressure-volume ratio of at least the brake circuit comprising the respective pump (26).

2. Control device (50) according to claim 1, wherein the electronic device (52) is designed to at least once the respective pressure-volume relation of the at least one pump circuit (26) comprising the brake circuit of the brake system taking into account at least one to the electronic device ( 26) provided print size (62,

PMC) with respect to a master cylinder pressure (PMC) in one

Master brake cylinder (18) of the brake system and at least one adjustment path variable (64, SMC) provided to the electronic device (52) with respect to an adjustment path (SMC) of at least one adjustable piston of the master brake cylinder (18).

3. Control device (50) additionally for at least one electric motor (56) which can be used as a generator, according to claim 1 or 2, wherein the electronic device (52) is designed, at least below

Taking into account at least one of the electronic device (52) predetermined or determined by the electronic device (52) target motor deceleration variable with respect to a target motor deceleration to be brought about by means of the at least one electric motor (56) to define at least one target operating variable of the respective electric motor (56), and the to control at least one electric motor (56) in accordance with at least its specified target operating variable in such a way that by means of regenerative operation of the at least one electric motor (56), the vehicle is actual with an at least one electric motor (56) that corresponds to at least its specified target operating variable - Motor deceleration can be braked.

4. Control device (50) according to claim 3, wherein the electronic device (52) is designed to determine the at least one target operating variable with additional consideration of the newly determined pressure-volume ratio.

5. Control device (50) according to one of the preceding claims, wherein the electronic device (52) is additionally designed to effect the at least one setpoint pressure difference variable with respect to that in the at least one wheel brake cylinder (16a, 16b) Brake pressure increase and / or the at least one setpoint motor deceleration variable with respect to the setpoint motor deceleration to be brought about by means of the at least one electric motor (56)

Taking into account at least one braking specification variable (60) with regard to one of a driver of the vehicle or an automatic one

Speed control device to set requested target vehicle deceleration of the vehicle.

6. A braking system for a vehicle comprising: a control device (50) according to any one of the preceding claims; the at least one pump (26) which can be controlled by means of the control device (50); the at least one wheel brake cylinder (16a, 16b) hydraulically connected on the delivery side to the at least one pump (26); and the at least one storage chamber (20) hydraulically connected on the suction side to the at least one pump (26).

7. A method for operating a braking system of a vehicle, comprising the steps:

Increase at least one brake pressure in at least one hydraulically connected on the delivery side to at least one pump (26)

Wheel brake cylinder (16a, 16b) of the brake system by means of the at least one pump (26) by:

- Setting at least one target variable with respect to a respective target speed of the at least one pump (26) at least below

Taking into account a brake pressure increase (S1) to be effected in the at least one wheel brake cylinder (16a, 16b); and - Controlling the at least one pump (26) in accordance with the specified target size such that the at least one pump (26) with an actual speed corresponding to its target size brake fluid from at least one storage chamber hydraulically connected to the respective pump (26) on the suction side (20) in the at least one

Wheel brake cylinder (16a, 16b) pumps (S2); characterized by the steps: at least once redetermining a respective pressure-volume relationship of at least one brake circuit of the brake system (SO) comprising the at least one pump (26); wherein when the at least one brake pressure in the at least one wheel brake cylinder (16a, 16b) is subsequently increased by means of the at least one pump (26), the at least one target variable with additional consideration of the newly determined pressure-volume ratio of at least the respective pump (26) comprehensive brake circuit is determined.

8. The method according to claim 7, wherein the respective pressure-volume ratio of at least one comprising the at least one pump (26)

Brake circuit of the brake system at least once

Taking into account at least one determined pressure variable (62, PMC) with regard to a master brake cylinder pressure (PMC) in one

Master brake cylinder (18) of the brake system and at least one determined displacement path variable (64, SMC) with respect to an adjustment path (SMC) of at least one adjustable piston of the master brake cylinder (18) is newly determined.

9. The method according to claim 7 or 8 with the additional steps:

Determining at least one target operating variable for at least one electric motor (56) of the vehicle which can be used as a generator, at least taking into account a target motor deceleration to be brought about by means of the at least one electric motor (56); Activation of the at least one electric motor (56) in accordance with at least its specified target operating variable such that, by means of regenerative operation of the at least one electric motor (56), the vehicle with an actual motor deceleration caused by the at least one electric motor and corresponding to at least its specified target operating variable is braked.

10. The method according to claim 9, wherein the at least one target operating variable with additional consideration of the newly determined pressure volume

Relation is established.