METHOD FOR DETERMINING A STARTING CONDITION FOR CLEANING A BRAKE DISK, METHOD FOR CLEANING A BRAKE DISK AND DATA PROCESSING DEVICE

Abstract

The disclosure relates to a method for determining a starting condition for cleaning a brake disk. A first step (S1) of this method determines that an amount of rust on the brake disk exceeds a defined threshold. Additionally, an energy quantity being necessary for removing the amount of rust from the brake disk is determined (S2). In a further step (S3), a distribution of brake energy over a current drive is estimated by using at least one parameter describing historic driving behavior and at least one parameter characterizing the current drive cycle. Subsequently, a starting speed and a starting brake force request is derived (S4). Additionally, a method for cleaning a brake disk is presented which comprises the determination of a starting condition for cleaning the brake disk by the method mentioned before. Moreover, a data processing device comprising means for carrying out said methods is explained.

Claims

1. Method for determining a starting condition for cleaning a brake disk, the method comprising determining that an amount of rust on the brake disk exceeds a defined threshold, determining an energy quantity being necessary for removing the amount of rust from the brake disk by pressing at least one corresponding brake pad against the brake disk, estimating a distribution of brake energy over a current drive cycle by using at least one parameter describing historic driving behavior and at least one parameter characterizing the current drive cycle, and deriving a starting speed and a starting brake force request from the distribution of brake energy, the starting speed and the starting brake force being determined such that the energy quantity to remove the determined amount of rust is fully applied to the brake disk during the current drive cycle.

2. The method of claim 1, wherein the amount of rust on the brake disk is determined by a rust formation model.

3. The method of claim 1, wherein the energy quantity to remove the amount of rust is determined by a rust removal model.

4. The method of claim 1, wherein a speed range does not comprise the starting speed.

5. The method of claim 1, wherein the historic driving behavior is described by a parameter relating to the occurrence of braking events per distance unit in function of a vehicle speed.

6. The method of claim 1, wherein the historic driving behavior is described by a parameter relating to the duration of historic braking events.

7. The method of claim 1, wherein the historic driving behavior is described by a parameter relating to a historic deceleration action.

8. The method of claim 1, wherein the historic driving behavior is described by a parameter relating to a distance or to a speed relative to a front vehicle.

9. The method of claim 1, wherein the historic driving behavior is described by a parameter relating to a historic speed relative to a corresponding speed limit.

10. The method of claim 1, wherein the historic driving behavior is described by a parameter relating to a historic power demand relative to a road slope.

11. The method of claim 1, wherein the current drive cycle is described by a parameter relating to at least one of a distance covered by the drive cycle, a slope distribution or a speed limit distribution.

12. The method of claim 1, wherein the current drive cycle is described by a parameter relating to a real time traffic situation.

13. The method of claim 1, wherein the at least one parameter describing historic driving behavior or the at least one parameter characterizing the current drive cycle is updated during the drive cycle.

14. A method for cleaning a brake disk, the method comprising: determining a starting condition for cleaning the brake disk, wherein the determining comprises: determining that an amount of rust on the brake disk exceeds a defined threshold, determining an energy quantity being necessary for removing the amount of rust from the brake disk by pressing at least one corresponding brake pad against the brake disk, estimating a distribution of brake energy over a current drive cycle by using at least one parameter describing historic driving behavior and at least one parameter characterizing the current drive cycle, and deriving a starting speed and a starting brake force request from the distribution of brake energy, the starting speed and the starting brake force being determined such that the energy quantity to remove the determined amount of rust is fully applied to the brake disk during the current drive cycle; and starting a brake disk cleaning procedure once the starting condition is detected during a drive cycle.

15. A data processing device comprising: one or more components configured to clean a brake disk, wherein a cleaning the brake disk comprises: determining a starting condition for cleaning the brake disk, wherein the determining comprises: determining that an amount of rust on the brake disk exceeds a defined threshold, determining an energy quantity being necessary for removing the amount of rust from the brake disk by pressing at least one corresponding brake pad against the brake disk, estimating a distribution of brake energy over a current drive cycle by using at least one parameter describing historic driving behavior and at least one parameter characterizing the current drive cycle, and deriving a starting speed and a starting brake force request from the distribution of brake energy, the starting speed and the starting brake force being determined such that the energy quantity to remove the determined amount of rust is fully applied to the brake disk during the current drive cycle; and starting a brake disk cleaning procedure once the starting condition is detected during a drive cycle.

16. A data processing device comprising: one or more components configured to determine a starting condition for cleaning a brake disk, wherein a determining the starting condition for cleaning the brake disk comprises: determining that an amount of rust on the brake disk exceeds a defined threshold, determining an energy quantity being necessary for removing the amount of rust from the brake disk by pressing at least one corresponding brake pad against the brake disk, estimating a distribution of brake energy over a current drive cycle by using at least one parameter describing historic driving behavior and at least one parameter characterizing the current drive cycle, and deriving a starting speed and a starting brake force request from the distribution of brake energy, the starting speed and the starting brake force being determined such that the energy quantity to remove the determined amount of rust is fully applied to the brake disk during the current drive cycle.

Description

[0043] Examples of the invention will be described in the following with reference to the following drawings:

[0044] FIG. 1 shows a data processing device according to the present disclosure comprising means for carrying out the method for determining a starting condition for cleaning a brake disk of the present disclosure and comprising means for carrying out the method for cleaning a brake disk of the present disclosure, wherein also input parameters and output parameters are presented,

[0045] FIG. 2 shows the method for cleaning a brake disk of the present disclosure comprising the method for determining a starting condition for cleaning a brake disk of the present disclosure,

[0046] FIG. 3 shows an example of a parameter describing historic driving behavior, and

[0047] FIG. 4 shows a representation of an estimation of a brake energy distribution.

[0048] The figures are merely schematic representations and serve only to illustrate examples of the invention. Identical or equivalent elements are in principle provided with the same reference signs.

[0049] FIG. 1 shows a data processing device 10 comprising means for carrying out the method for determining a starting condition for cleaning a brake disk and for carrying out the method for cleaning a brake disk.

[0050] The data processing device 10 comprises a brake force allocation unit 12.

[0051] The brake force allocation unit 12 is connected to a foundation brake controller 14 and an electric traction motor controller 16.

[0052] The brake force allocation unit 12 and its connections are configured such that the brake force allocation unit 12 is able to selectively send a brake force request to the foundation brake controller 14 and/or the electric traction motor controller 16. Additionally, the electric traction motor controller 16 can provide operational conditions of the electric traction motor to the brake force allocation unit 12.

[0053] An example of such operational conditions is the achievable lowest limit of negative torque which is a function of speed, and temperature. This parameter restricts the torque being available for regenerative braking.

[0054] Furthermore, the brake force allocation unit 12 is configured for receiving a brake force request 18 as an input parameter. The brake force request 18 can be generated by a human driver by pressing a brake pedal or by an autonomous driver or a partly autonomous driver. A partly autonomous driver for example comprises an adaptive cruise control unit being able to generate a brake force request. A fully autonomous driver is for example a driving control unit of a fully autonomous vehicle.

[0055] The brake force allocation unit 12 is further configured to receive a vehicle speed 20 and operational conditions 22 being operational conditions of an electric storage device and an engine as input parameters.

[0056] In more detail, the operational conditions 22 are received from control units of the electric storage device and the engine respectively.

[0057] For example, an operational condition 22 of the electric storage device may describe that its state-of-charge is full. In such a case, regenerative braking is not possible.

[0058] An operational condition 22 of the engine for example relates to the achievable lowest limit of negative torque which is a function of speed and temperature. This parameter describes a braking effect being achievable by an engine drag torque.

[0059] Thus, the brake force allocation unit 12 is configured for sending a brake force request to at least one of the foundation brake controller 14 and an electric traction motor controller 16 in function of the above input parameters and operational conditions.

[0060] Moreover, the data processing device 10 comprises a rust prediction unit 24.

[0061] The rust prediction unit 24 is configured such that a rust formation model and a rust removal model can be run thereon.

[0062] Furthermore, the rust prediction unit 24 is configured to receive a system time parameter 26 and at least one environmental condition parameter 28. In the present example, the environmental condition parameter 28 comprises a value relating to an ambient temperature and a value relating to humidity.

[0063] Additionally, the rust prediction unit 24 is configured for receiving a brake request for the foundation brake controller 14 as an input parameter.

[0064] The rust formation model uses the system time parameter 26 and the environmental condition parameter 28 as input parameters to estimate an amount of rust being formed on the brake disk.

[0065] The rust removal model predicts an amount of rust which is removed from the brake disk by evaluating the brake request for the foundation brake controller 14.

[0066] Since on the rust prediction unit 24 both the rust formation model and the rust removal model are run, the rust prediction unit 24 is able to always provide an estimation of a current amount of rust being present on the brake disk.

[0067] The rust prediction unit 24 is connected to the brake force allocation unit 12 unit such that the estimation of the current amount of rust can be communicated from the rust prediction unit 24 to the brake force allocation unit 12.

[0068] The data processing device 10 further comprises a brake disk cleaning control unit 30 being configured for providing at least one starting condition for a brake disk cleaning procedure.

[0069] In the present example the at least one starting condition for a brake disk cleaning procedure comprises a starting speed and a starting brake force request.

[0070] The brake disk cleaning control unit 30 is connected to the brake force allocation unit 12 such that these starting conditions can be communicated.

[0071] In the present example, the starting conditions are not fixed, but calculated in function of parameters being provided by a drive cycle prediction unit 32 and a driving behavior history unit 34.

[0072] The drive cycle prediction unit 32 receives input parameters characterizing a current drive cycle from a navigation unit 36 and from a front radar unit 38 of the vehicle.

[0073] The drive cycle prediction unit 32 is further configured to generate an output parameter characterizing the current drive cycle in dependency of the mentioned input parameters.

[0074] In order to communicate the parameter characterizing the current drive cycle to the brake disk cleaning control unit 30, the brake disk cleaning control unit 30 and the drive cycle prediction unit 32 are connected.

[0075] The driving behavior history unit 34 uses a record of historic vehicle speed 40 and a record of historic brake force requests 42 as input parameters.

[0076] Additionally, historic road information 44 and historic results from front radar 38 are used.

[0077] Using the above input parameters, the driving behavior history unit 34 provides at least one parameter describing historic driving behavior to the brake disk cleaning control unit 30. To this end, the brake disk cleaning control unit 30 and the driving behavior history unit 34 are connected.

[0078] The data processing device 10 thus is configured for carrying out the method for determining a starting condition for cleaning a brake disk (cf. FIG. 2).

[0079] This method comprises a first step S1 which consists in determining that an amount of rust on the brake disk exceeds a defined threshold. This is done by running the rust formation model on the rust prediction unit 24. The defined threshold is also stored on the rust prediction unit 24.

[0080] In a second step S2, an energy quantity being necessary for removing the amount of rust from the brake disk by pressing at least one corresponding brake pad against the brake disk is determined. This is done by running the rust formation model on the rust prediction unit 24.

[0081] A third step S3 consists in estimating a distribution of brake energy over a current drive cycle by using at least one parameter describing historic driving behavior being provided by the driving behavior history unit 34 and at least one parameter characterizing the current drive cycle being provided by the drive cycle prediction unit 32.

[0082] In the present example, the current drive cycle, i.e. the remaining portion of the current drive cycle is described by a parameter relating to a distance covered by the drive cycle, a slope distribution of the drive cycle and a speed limit distribution over the drive cycle. These parameters are provided by the navigation unit 36.

[0083] Furthermore, the current drive cycle is described by a parameter relating to a real time traffic situation. This kind of information influences the route selected by the navigation unit 36, i.e. on the distance covered by the drive cycle and the slope distribution of the drive cycle. Moreover, the speed limit distribution can be adapted due to the real time traffic situation.

[0084] Thus, a characterization of the current drive cycle is available for the brake disk cleaning control unit 30.

[0085] An aspect of the historic driving behavior is described by a parameter relating to the occurrence of braking events per distance unit in function of a vehicle speed. This information forms part of the record of historic brake force requests 42. An exemplary representation is given in FIG. 3, wherein the vehicle speed is noted on the horizontal axis and the quantity of braking events per distance unit, here per kilometer, is noted on the vertical axis. A curve has been fitted through the points of measurement being indicated by crosses.

[0086] The historic driving behavior is also described by a parameter relating to the duration of historic braking events, e.g. an average duration. This information is also provided by the record of historic brake force requests 42.

[0087] Moreover, the historic driving behavior is described by a parameter relating to a historic deceleration action. In the present example, this parameter relates to an average historic brake pedal positon. This information is also provided by the record of historic brake force requests 42.

[0088] The historic driving behavior is additionally described by a parameter relating to a historic speed relative to a corresponding speed limit. This parameter can be imagined as an average offset from the speed limit, e.g. a few km/h below the speed limit. This information is provided by the records of historic vehicle speed 40.

[0089] Furthermore, the historic driving behavior is described by a parameter relating to a historic power demand relative to a road slope. The historic power demand is defined to be positive for power being provided by the engine or the electric traction machine of the vehicle. Power being provided to the vehicle, e.g. because it drives down a very steep road is defined to be negative. This information is part of the historic road information 44.

[0090] The historic driving behavior is further described by a parameter relating to a distance and/or to a speed relative to a front vehicle. Exemplary parameters can relate to an average historic distance or an average historic speed. This kind of information is provided by the front radar 38.

[0091] Taking into account, all the parameters characterizing the current drive cycle and relating to historic driving behavior, a distribution of brake energy over the current drive cycle can be estimated.

[0092] In more detail, the distance covered by the drive cycle, the corresponding slope distribution and the corresponding speed limits are known from the navigation unit 36.

[0093] Now the parameter relating to the historic speed relative to the speed limit is used in order to estimate a speed distribution over the current drive cycle.

[0094] Additionally, the parameter relating to the historic power demand relative to the road slope is applied to the slope distribution provided by the navigation unit 36, thus an estimated distribution of power demand over the current drive cycle is known. Based thereon, changes in power demand can be assessed and it is possible to evaluate which changes relate to a deceleration of the vehicle, i.e. are related to a braking activity. It is noted that due to the speed distribution mentioned above, it is known at which speed the braking event will take place.

[0095] A likelihood of a braking event can be further described by the average historic distance or an average historic speed relative to a front vehicle.

[0096] Furthermore, due to the above mentioned parameters concerning historic driving behavior, it is possible to estimate the quantity and duration of the braking events which will be used to realize the changes in power demand leading to the above decelerations. Due to the parameter relating to the historic brake pedal position, the intensity of the brake actuation can be estimated.

[0097] Thus, a distribution of brake energy over the current drive cycle can be estimated. An exemplary distribution is shown in FIG. 4, which shows a group of probability density functions for different speed ranges. On the horizontal axis the braking energy is noted.

[0098] Based thereon, in a fourth step S4, a starting speed and a starting brake force request is derived from the distribution of brake energy. The starting speed and the starting brake force request are determined such that the energy quantity being necessary for removing the determined amount of rust is fully applied to the brake disk during the current drive cycle. This means, that in a drive cycle of comparatively low speed, potentially a low starting speed is derived. If additionally, the parameters about the historic driving behavior show that the brake pedal has been pressed with rather high caution, also a comparatively low starting brake force request will be determined. In contrast thereto, for a drive cycle in which braking events of high intensity at high speed are to be expected, the starting speed may be comparatively high. The same applies to the starting brake force request.

[0099] Once the starting speed has been derived, a check is performed if it falls within a speed range which must not comprise the starting speed. In this case the starting speed may be corrected such that it falls just outside this speed range.

[0100] It is further noted that the at least one parameter describing the historic driving behavior and the parameters characterizing the current drive cycle are periodically updated during the drive cycle.

[0101] The data processing device 10 is also configured for carrying out the method for cleaning a brake disk (cf. FIG. 2).

[0102] This method determines the starting speed and the starting brake force by using the method for determining a starting condition for cleaning a brake disk comprising steps S1 to S4 as has been explained above.

[0103] The brake force allocation unit 12 starts a brake disk cleaning procedure once these starting conditions are met during a drive cycle. This constitutes a fifth step S5 if the initial numbering is continued.

[0104] The cleaning procedure is terminated once the rust is removed entirely or if the estimated amount of rust falls below a termination threshold.

[0105] Other variations to the disclosed examples can be understood and effected by those skilled in the art in practicing the claimed invention, from the study of the drawings, the disclosure, and the appended claims. In the claims the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items or steps recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope of the claims.

LIST OF REFERENCE SIGNS

[0106] 10 data processing device

[0107] 12 brake force allocation unit

[0108] 14 foundation brake controller

[0109] 16 electric traction motor controller

[0110] 18 brake force request

[0111] 20 vehicle speed

[0112] 22 operational conditions

[0113] 24 rust prediction unit

[0114] 26 system time parameter

[0115] 28 environmental condition parameter

[0116] 30 brake disk cleaning control unit

[0117] 32 drive cycle prediction unit

[0118] 34 driving behavior history unit

[0119] 36 navigation unit

[0120] 38 front radar unit

[0121] 40 record of historic vehicle speed

[0122] 42 record of historic brake force requests

[0123] 44 historic road information

[0124] S1 first step

[0125] S2 second step

[0126] S3 third step

[0127] S4 fourth step

[0128] S5 fifth step