WO2022096299A1 - STEUERVORRICHTUNG UND VERFAHREN ZUM BESTIMMEN EINER p-V-CHARAKTERISTIK ZUMINDEST EINES RADBREMSZYLINDERS EINES BREMSSYSTEMS EINES FAHRZEUGS - Google Patents
STEUERVORRICHTUNG UND VERFAHREN ZUM BESTIMMEN EINER p-V-CHARAKTERISTIK ZUMINDEST EINES RADBREMSZYLINDERS EINES BREMSSYSTEMS EINES FAHRZEUGS Download PDFInfo
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- WO2022096299A1 WO2022096299A1 PCT/EP2021/079483 EP2021079483W WO2022096299A1 WO 2022096299 A1 WO2022096299 A1 WO 2022096299A1 EP 2021079483 W EP2021079483 W EP 2021079483W WO 2022096299 A1 WO2022096299 A1 WO 2022096299A1
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- Prior art keywords
- pressure
- wheel
- brake cylinder
- wheel brake
- valve
- Prior art date
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- 238000000034 method Methods 0.000 title claims abstract description 52
- 238000005259 measurement Methods 0.000 claims abstract description 23
- 239000012530 fluid Substances 0.000 claims description 22
- 238000011144 upstream manufacturing Methods 0.000 claims description 14
- 238000002955 isolation Methods 0.000 claims description 6
- 230000001960 triggered effect Effects 0.000 claims description 4
- 238000007789 sealing Methods 0.000 description 7
- 238000006073 displacement reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000005236 sound signal Effects 0.000 description 2
- 230000003679 aging effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000740 bleeding effect Effects 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 238000013022 venting Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
- B60T17/18—Safety devices; Monitoring
- B60T17/22—Devices for monitoring or checking brake systems; Signal devices
- B60T17/221—Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
- B60T17/18—Safety devices; Monitoring
- B60T17/22—Devices for monitoring or checking brake systems; Signal devices
- B60T17/221—Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems
- B60T17/222—Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems by filling or bleeding of hydraulic systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
- B60T13/683—Electrical control in fluid-pressure brake systems by electrically-controlled valves in pneumatic systems or parts thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
- B60T8/88—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means
- B60T8/885—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means using electrical circuitry
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/10—ABS control systems
- B60T2270/14—ABS control systems hydraulic model
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/20—ASR control systems
- B60T2270/203—ASR control systems hydraulic system components
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/30—ESP control system
- B60T2270/306—ESP control system hydraulic system components
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/40—Failsafe aspects of brake control systems
- B60T2270/406—Test-mode; Self-diagnosis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
- B60Y2400/00—Special features of vehicle units
- B60Y2400/81—Braking systems
Definitions
- the invention relates to a method for determining a p-V characteristic of at least one wheel brake cylinder of a braking system of a vehicle.
- the invention also relates to a control device for a braking system of a vehicle and a braking system for a vehicle.
- 1a to 1e show coordinate systems for explaining a conventional procedure for defining a p-V characteristic of at least one wheel brake cylinder of a vehicle brake system.
- the conventional procedure described below is known to the applicant as internal prior art.
- the abscissa is in each case a time axis t.
- a pressure p present in a first wheel brake cylinder of the vehicle's own braking system is reproduced by means of the ordinate of the coordinate system in FIG. (However, the vehicle's own brake system has three more wheel brake cylinders .)
- the ordinate of the coordinate system in Fig. lc a current intensity li npu t2-4 of the control signals output to the three other wheel inlet valves of the three other wheel brake cylinders is reproduced.
- the ordinate of the coordinate system in FIG . 4 of the control signals output to the three other wheel outlet valves of the three other wheel brake cylinders. While the wheel inlet valves are normally open valves, the wheel outlet valves are normally closed valves.
- the pressure p present in the first wheel brake cylinder is increased during a measurement time interval AtM.
- the brake pressure increase in the first wheel brake cylinder is brought about by moving brake fluid via the open-controlled first wheel inlet valve into the first wheel brake cylinder, while the other three wheel inlet valves and all four wheel outlet valves are closed during the measuring time interval AtM.
- a volume variable reflecting a current volume in the first wheel brake cylinder and a pressure variable reflecting the current pressure p in the first wheel brake cylinder are determined at least once during the measuring time interval AtM.
- the p-V characteristic of the first wheel brake cylinder can then be determined based on the at least one volume variable and the at least one pressure variable.
- the invention creates a method for determining a p-V characteristic of at least one wheel brake cylinder of a brake system of a vehicle with the features of claim 1, a control device for a brake system of a vehicle with the features of claim 7 and a brake system for a vehicle with the features of claim 10 .
- the present invention creates improved options for precisely and error-free determining a pV characteristic of at least one wheel brake cylinder of a braking system of a vehicle, such as an elasticity of the at least one wheel brake cylinder and/or a stiffness of the at least one wheel brake cylinder.
- a wheel-specific/wheel-brake cylinder-specific pV characteristic of a single wheel-brake cylinder can be determined precisely and reliably using the present invention (for all wheel brake cylinders of the respective brake system).
- the possibilities created by means of the present invention can determine/measure the pV characteristic independently or independently adapt a value stored as a pV characteristic to the actual pV characteristic of the at least one wheel brake cylinder.
- the determined or adapted PV characteristic of the at least one wheel brake cylinder can then be stored directly in a control device or on a storage unit. While using the conventional procedure described above, such processes can only be reliably carried out in a workshop during a development and application process of the respective brake system, since individual wheel brake lines of the brake system have to be screwed on and / or special high-priced devices are required, the present invention makes it possible even outside of a Workshop a reliable determination of the pV characteristics of at least one wheel brake cylinder.
- the present invention creates possibilities for checking a quality and a tolerance level of at least the wheel brake cylinders of a brake system installed on a vehicle by executing a routine.
- a further particular advantage of the present invention is that by using it, the p-V characteristic of the at least one wheel brake cylinder can be redetermined/corrected again and again during operation of the respective brake system without a visit to the workshop being necessary. This is associated with considerable cost savings, with the performance of the respective brake system being able to be kept at a high level through the repeatedly verified or corrected knowledge of the p-V characteristic of the at least one wheel brake cylinder.
- the “true” p-V relationship can be determined again and again, which means that the effects of aging effects on the brake system can be counteracted (in particular without having to bleed again on at least one wheel brake cylinder of the respective brake system).
- a partial volume pressure present in a partial volume of the brake system delimited by the at least one closed isolating valve increases to at least the limit pressure by means of a driver braking force exerted on a brake pedal of the brake system and/or by means of operation of a motorized brake pressure build-up device - equal to 25 bar is increased, with the at least one separating valve being opened at the beginning of a second pressure increase interval, whereby brake fluid with the averaged pressure build-up gradient greater than or equal to 50 bar/second from the partial volume (48) via the at least one separating valve (28a) to the at least one wheel inlet valve ( 30a) is postponed.
- the procedure described in this paragraph enables the desired pressure to be obtained successively on the at least one isolating valve and on the at least one wheel inlet valve during the pressure increase interval, wherein the at least one wheel inlet valve, at least one check valve arranged parallel to the at least one wheel inlet valve and the at least one isolating valve are sealed so reliably that they have no influence whatsoever on the increase in Have pressure in the at least one wheel brake cylinder during the measurement interval.
- the pressure present in the at least one wheel brake cylinder is reduced during a pressure reduction interval by draining brake fluid from the at least one wheel brake cylinder via at least one wheel outlet valve of the brake system arranged downstream of the at least one wheel brake cylinder. Draining brake fluid via the at least one wheel outlet valve has no effect on the reliable sealing effected during the pressure increase interval of the at least one wheel inlet valve, the at least one check valve and/or the at least one isolating valve.
- the pressure present in the at least one wheel brake cylinder can be increased during the measuring time interval with an averaged pressure build-up gradient of less than or equal to 35 bar/second.
- Such a “slow” increase in pressure enables the at least one volume variable and at the same time the at least one pressure variable to be determined precisely, so that the p-V characteristic can be defined very precisely.
- the at least one wheel inlet valve, the at least one check valve and/or the at least one isolating valve are therefore already in their respective closed positions before the measurement time interval, so that during the displacement of brake fluid into the at least one wheel brake cylinder carried out in the measurement time interval, no brake fluid volume is recorded due to insufficient sealing of the at least one wheel inlet valve, the at least one check valve and/or the at least one isolating valve is "lost". This allows more precise knowledge of the brake fluid volume that has been displaced in the at least one wheel brake cylinder, and thus also a more precise and more reliable definition of the pV characteristic.
- the pressure present in the at least one wheel brake cylinder before the at least one pressure increase interval, can be increased during a clearance closing interval to a clearance closing pressure greater than or equal to 40 bar, and then and before the at least one pressure increase interval, the pressure present in the at least one wheel brake cylinder be reduced to an outlet pressure of less than or equal to 5 bar.
- the electronic device can also be designed and/or programmed to cause during a first pressure increase interval or to detect on the basis of at least one sensor signal that is provided that a partial volume pressure present in a partial volume of the brake system that is delimited by the at least one closed isolating valve at least at the end of the first pressure increase interval by means of a brake pedal of the braking system exerted driver braking force and/or by means of operation of a motorized brake pressure build-up device is increased to at least the limit pressure greater than or equal to 25 bar, and at the beginning of a second pressure increase interval to open the at least one isolating valve in such a way that a brake fluid displacement with the averaged pressure build-up gradient greater than or equal to 50 bar/ Second is triggered from the partial volume via the at least one isolation valve to the at least
- the electronic device can be designed and/or programmed to control a motorized plunger device integrated into the brake system, an electromechanical brake booster upstream of a master brake cylinder of the brake system, or a pump motor of at least one pump of the brake system as the motorized brake pressure buildup device during the first pressure increase interval in such a way that the partial volume pressure is increased by means of the controlled motorized brake pressure build-up device at least at the end of the first pressure increase interval to at least the limit pressure greater than or equal to 25 bar.
- the advantages described above are also ensured in a corresponding brake system for a vehicle with such a control device, the at least one wheel brake cylinder, and the at least one wheel inlet valve arranged upstream of the at least one wheel brake cylinder and/or the at least one separating valve arranged upstream of the at least one wheel brake cylinder.
- the braking system can also be developed according to the above-explained embodiments of the method.
- 1a to 1e coordinate systems for explaining a conventional procedure for defining a pV characteristic of at least one wheel brake cylinder of a vehicle brake system
- 2a to 2k a schematic representation of a brake system and coordinate systems for explaining an embodiment of the method for determining a pV characteristic of at least one wheel brake cylinder of the brake system
- Fig. 3 is a schematic representation of an embodiment of
- FIGS. 2a to 2k show a schematic representation of a brake system and coordinate systems for explaining an embodiment of the method for determining a p-V characteristic of at least one wheel brake cylinder of the brake system.
- FIG. 2a shows an example of a brake system of a vehicle for which the method described below for determining a p-V characteristic of at least one wheel brake cylinder 10a can be used. It is pointed out, however, that the method described below is not limited to the brake system type shown schematically in FIG. 2a or to a special vehicle type/motor vehicle type of the vehicle/motor vehicle equipped with the respective brake system. For example, the total number of exactly four wheel brake cylinders 10a to 10d of the brake system shown in FIG. 2a is only to be interpreted as an example.
- a first wheel brake cylinder 10a and a second wheel brake cylinder 10b are connected to a first brake circuit of the brake system, while a third wheel brake cylinder 10c and a fourth wheel brake cylinder 10d are connected to the second brake circuit of the brake system.
- a wheel-specific/wheel-brake cylinder-specific pV characteristic of the first wheel brake cylinder 10a is determined.
- the method described below can also be carried out correspondingly for the other three wheel brake cylinders 10b to 10d.
- a pV characteristic of more than just one of the wheel brake cylinders 10a to 10d can also be defined.
- this also applies to a vehicle/motor vehicle with fewer or more than four wheel brake cylinders 10a to 10d, such as on a 3-axle vehicle.
- the embodiment of the method reproduced by means of FIGS. 2a to 2k begins, for example, with a closing of a clearance of at least the first wheel brake cylinder 10a by increasing at least the pressure present in the first wheel brake cylinder 10a to a clearance closing pressure greater than or equal to 40 bar during a so-called clearance closing interval Atdearance will.
- the brake linings of all wheel brake cylinders 10a to 10d can be completely applied during the air gap closing interval Atdearance by means of a pressure build-up effected in the wheel brake cylinders 10a to 10d, which ensures that the air play of the wheel brake cylinders 10a to 10d does not affect the method steps described below.
- the pressure build-up brought about at least in the first wheel brake cylinder 10a during the clearance closing interval Atdearance can in particular be greater than or equal to 80 bar, for example greater than or equal to 120 bar, specifically greater than or equal to 180 bar.
- the numerical values given here are only to be interpreted as examples.
- the brake system shown schematically in FIG. 2a has, for example, a motorized plunger device 12 as a motorized brake pressure build-up device for bringing about the brake pressure build-up at least in the first wheel brake cylinder 10a during the clearance closing interval Atdearance.
- the motorized plunger device 12 can in particular be a piston-cylinder device integrated into the braking system, such as in particular an I PB (Integrated Power Brake) device.
- motorized brake pressure build-up devices such as an electromechanical brake booster upstream of a master brake cylinder 14 of the brake system or a pump motor of at least one pump of the brake system, can also be used to cause the brake pressure build-up at least in the first wheel brake cylinder 10a can be used or shared during the air gap closing interval Atdearance.
- a driver braking force exerted on a brake pedal 16 of the brake system which can be detected in particular by means of a rod travel sensor 18 and/or by means of a differential travel sensor 20, can also be used or shared to bring about the pressure build-up at least in the first wheel brake cylinder 10a .
- a pressure build-up caused by the driver braking force at least in master brake cylinder 14 and/or a volume displaced by the driver braking force can then be reliably estimated from the driver braking force, usually using a characteristic curve stored on a computer. It is therefore often not necessary to use a sensor to measure the volume displaced by the driver braking force.
- a driver of the respective vehicle, or an operator or mechanic can also be prompted by means of a light signal, an audio signal and/or an image display to exert a correspondingly high driver braking force on the brake pedal 16 of his vehicle.
- the coordinate systems of FIGS. 2b to 2k each have a time axis t as the abscissa.
- the coordinate system in FIG. 2b has a pressure pi2 present on/in the motorized plunger device 12 as the ordinate, while the ordinate of the coordinate system in FIG. 2c indicates an adjustment path x of a piston of the motorized plunger device 12 from its initial position.
- the adjustment path x can be determined, for example, by means of a rotor position sensor 22 of a motor 24 of the motorized plunger device 12 .
- the motor 24 of the motorized plunger device 12 can also be equipped with a motor current sensor 26 .
- the motorized plunger device 12 is connected to the first brake circuit of the brake system via a first isolating valve 28a and to the second brake circuit of the brake system via a second isolating valve 28b.
- the coordinate systems of FIGS. 2d and 2e indicate, by means of their ordinates, a current intensity hsa of a control signal output to the first cut valve 28a and a current intensity hsb of a control signal output to the second cut valve 28b.
- the isolating valves 28a and 28b are each normally closed valves.
- each wheel brake cylinder 10a to 10d is preceded by a wheel inlet valve 30a to 30d and a wheel outlet valve 32a to 32d is arranged downstream. While the wheel inlet valves 30a to 30d are normally open valves, the wheel outlet valves 32a to 32d are normally closed valves.
- the ordinate of the coordinate system in FIG. 2f shows a current intensity Loa of a control signal which is output to a first wheel inlet valve 30a arranged upstream of the first wheel brake cylinder 10a.
- the current strengths Isob-sod of the control signals provided to the other wheel inlet valves 30b to 30d are represented by the ordinate of the coordinate system of FIG. 2g.
- a first wheel outlet valve 32a arranged downstream of first wheel brake cylinder 10a is activated by means of a control signal whose current intensity 132a is shown by means of the ordinate of the coordinate system in FIG. 2h.
- the current strengths l32b-32d of the control signals of the other wheel outlet valves 32b to 32d are indicated by means of the ordinate of the coordinate system of FIG. 2i.
- the first brake circuit of the brake system of FIG. 2a is also connected to master brake cylinder 10 via a first decoupling valve 34a, while its second brake circuit is connected to master brake cylinder 10 via a second decoupling valve 34b.
- the decoupling valves 34a and 34b are each normally open valves.
- the ordinate of the coordinate system of Fig. 2j indicates a current Is4a of a control signal output to the first cutoff valve 34a
- the ordinate of the coordinate system of Fig. 2k indicates a current Is4b of a control signal output to the second cutoff valve 34b.
- all wheel brake cylinders 10a to 10d can be decoupled from the master brake cylinder 10, with the driver actuating the brake pedal 16 being able to brake in a simulator 38 via a simulator connection valve 36 if necessary.
- the master brake cylinder 14 can also be connected to a brake fluid reservoir 42 via a reservoir decoupling valve 40 .
- a pre-pressure sensor 44 can also be connected to master brake cylinder 14 .
- the closing of the clearances of the wheel brake cylinders 10a to 10d creates advantageous, reproducible conditions for carrying out the method steps described below, but is only an optional method step of the embodiment of the method described here.
- the pressure in the first wheel brake cylinder 10a is reduced to an initial pressure of less than or equal to 5 bar, preferably to an initial pressure equal to atmospheric pressure.
- a pressure exerted on at least the closed first wheel inlet valve 30a and/or the closed first separating valve 28a during at least one pressure increase interval Atincreasei and AtinC rease2 with an average pressure build-up gradient greater than or equal to 50 bar/second is increased to a limit pressure greater than or equal to 25 bar.
- the limit pressure can in particular be greater than or equal to 40 bar, for example greater than or equal to 60 bar, especially greater than or equal to 80 bar.
- the average pressure build-up gradient of the pressure increase in the first wheel brake cylinder 10a during the at least one pressure increase interval Atincreasei and Ati nC rease2 can be greater than or equal to 60 bar/second, eg greater than or equal to 70 bar/second, specifically greater than or equal to 80 bar/second.
- the averaged pressure build-up gradient can be a quotient of the pressure increase caused at the respective valve 28a or 30a during the respective pressure increase interval Atincreasei and Atincrease2 divided by a duration of the respective pressure increase interval Atincreasei and Atincrease2.
- the pressure exerted on at least the closed first wheel inlet valve 30a and/or the closed first separating valve 28a with the averaged Pressure build-up gradients greater than or equal to 50 bar/second up to the limit pressure greater than or equal to 25 bar causes pressurization of at least the first wheel inlet valve 30a, a first check valve 46a arranged parallel to the first wheel inlet valve 30a and the first isolating valve 28a during the at least one pressure increase interval Atincreasei and Ati nC release2 so that their valve bodies are pressed against the respective valve seat.
- the pressure with the average pressure build-up gradient greater than or equal to 50 bar/second up to the limit pressure greater than or equal to 25 bar can be applied to all closed isolating valves 28a and 28b and to all closed wheel inlet valves 30a to 30d during the at least one pressure increase interval Atincreasei and AtinC rease2 .
- this causes both a pressurization of the isolating valves 28a and 28b and a pressurization of the wheel inlet valves 30a to 30d and their check valves 46a to 46d arranged parallel to the respective wheel inlet valve 30a to 30d, whereby the valve bodies of the respective valves 28a and 28b, 30a to 30d and 46a to 46d are pressed against their respective valve seats and in this way the valves 28a and 28b, 30a to 30d and 46a to 46d are sealed.
- the valve bodies of the check valves 46a to 46d are pressed against their respective valve seat and the check valves 46a to 46d are thus closed in the best possible way.
- valves 28a and 28b, 30a to 30d and 46a to 46d which is effected in particular by means of the comparatively high pressure build-up gradient, prevents manufacturing tolerances, such as in particular manufacturing tolerances on the check valves, from occurring during a pressure build-up in the first wheel brake cylinder 10a, which is described below 46a to 46d, could result in leakage at an unreliably sealed valve, which could "lost" volume.
- the method steps executed during the at least one pressure increase interval Atincreasei and AtinC rease2 thus bring about an advantageous preconditioning of the valves 28a and 28b, 30a to 30d and 46a to 46d for precise and error-free determination of the pV characteristic.
- Partial volume 48 is a volume of the brake system that is delimited at least by the closed first isolating valve 28a (and optionally also by the closed second isolating valve 28b), so that by opening at least the first isolating valve 28a, brake fluid is displaced from the partial volume 48 to the closed first wheel inlet valve 30a can be triggered.
- the above-described comparatively high averaged pressure build-up gradient greater than or equal to 50 bar/second can thus be brought about by opening at least the first separating valve 28a and possibly also the second separating valve 28b at the beginning of a second pressure increase interval Atincrease2.
- a "sudden pressure build-up" with the comparatively high averaged pressure increase gradient can be triggered at all wheel inlet valves 30a to 30d in this way.
- the "sudden pressure build-up" with the comparatively high average pressure increase gradient can also be brought about when the motorized plunger device 12, another type of motorized brake pressure build-up device used and/or the driver's braking force currently being exerted on the brake pedal 16 is not sufficient to cause a such high gradients is suitable.
- a comparatively inexpensive motorized plunger device 12 with a relatively low-power motor 24 or another inexpensive type of motorized brake pressure build-up device can also be advantageously used to carry out the method described here.
- the driver's braking force exerted on the brake pedal 16 can be used by means of the advantageous procedure described here to bring about the comparatively high averaged pressure build-up gradient, for which the driver of the respective vehicle may be prompted to actuate the brake pedal 16 by means of a light signal, an audio signal and an image display will.
- the isolating valves 28a and 28b are first opened "suddenly" in the method described here, which leads to a "rapid" pressure build-up at the wheel inlet valves 30a to 30d and their check valves 46a to 46d, whereby the valves 28a, 28b, 30a to 30d, 32a to 32d can be reliably sealed.
- the first wheel inlet valve 30a is then also opened.
- the pressure in first wheel brake cylinder 10a is reduced during a pressure reduction interval Atdecrease. This is done by draining brake fluid from the first wheel brake cylinder 10a via the first wheel outlet valve 32a.
- the first decoupling valve 34a can be opened briefly. The sealing of the valves 28a, 28b, 30a to 30d, 32a to 32d kept closed during the pressure reduction interval Atdecrease is thus not impaired by the pressure reduction in the first wheel brake cylinder 10a carried out during the pressure reduction interval Atdecrease.
- the pressure reduction in the first wheel brake cylinder 10a caused by the discharge of brake fluid from the first wheel brake cylinder 10a via the first wheel outlet valve 32a does not require the motorized plunger device 12 to be retracted, so that it is ensured at this point in time that a snifting hole of the motorized plunger device 12 is/remains closed .
- the pressure present in the first wheel brake cylinder 10a is increased during the measurement time interval Atmeasure by moving brake fluid via the first separating valve 28a and the first wheel inlet valve 30a into the first wheel brake cylinder 10a by means of the motorized plunger device 12 .
- a volume variable x representing a current volume in the first wheel brake cylinder 10a and a pressure variable p representing the current pressure in the first wheel brake cylinder 10a are determined at the same time.
- the pressure present in the first wheel brake cylinder 10a is preferably increased during the measurement time interval Atmeasure with an averaged pressure build-up gradient of less than or equal to 35 bar/second.
- the p-V course of the pressure present in the first wheel brake cylinder 10a can thus be recorded without any problems by means of a large number of measuring steps for the simultaneous determination of the pressure variable p and the volume variable x.
- the pressure in first wheel brake cylinder 10a can be measured as pressure variable p by means of a pressure sensor 50.
- the adjustment path x of the piston of the motorized plunger device 12 from its starting position, for example by means of the rotor position sensor 22 of the motor 24, can be determined as the volume variable x.
- the current volume in the first wheel brake cylinder 10a can be calculated using the displacement path x and a radius r of the piston of the motorized plunger device 12 . A volume flow measurement is therefore not necessary.
- the sealing effected during the at least one pressure increase interval Atincreasei and AtinC rease2 at least the first wheel inlet valve 30a, the first check valve 46a and the first isolating valve 28a ensures that the adjustment path x (essentially) corresponds to the current volume in the first wheel brake cylinder 10a is equivalent to.
- the pV characteristic of the first wheel brake cylinder 10a is determined taking into account the at least one volume variable x and the at least one pressure variable p.
- a single value or a pV characteristic can be specified as the pV characteristic.
- the determined pV characteristic can be a wheel-specific/wheel brake cylinder-specific pV characteristic.
- an elasticity of the first wheel brake cylinder 10a according to Equation (Eq. 1) or a rigidity Z of the first wheel brake cylinder 10a according to Equation (Eq. 2) can be defined as the pV characteristic with:
- K and K' each reflect a correction value defined by the internal elasticity of the braking system or the internal rigidity of the braking system.
- FIG. 3 shows a schematic representation of an embodiment of the control device.
- a usability of the control device 52 described below is neither limited to a specific type of brake system nor to a special vehicle type/motor vehicle type of the vehicle/motor vehicle equipped with the respective brake system.
- Control device 52 has an electronic device 54, the first subunit 56 of which is designed and/or programmed to switch at least one wheel inlet valve of the brake system arranged upstream of at least one wheel brake cylinder of the brake system and/or at least one isolating valve of the respective brake system arranged upstream of the at least one wheel brake cylinder.
- the first subunit 56 can be designed/programmed in particular as a pressure regulator and valve control of the respective brake system.
- First sub-unit 56 is primarily designed and/or programmed for this purpose, prior to at least one measurement carried out to determine a p-V characteristic of the at least one wheel brake cylinder first during at least one pressure increase interval to increase a pressure exerted on at least the at least one closed wheel inlet valve and/or the at least one closed separating valve with an average pressure build-up gradient greater than or equal to 50 bar/second up to a limit pressure greater than or equal to 25 bar.
- Possibilities for bringing about the advantageous shifting of brake fluid into the at least one wheel brake cylinder have already been listed above.
- first subunit 56 increase a pressure present in the at least one wheel brake cylinder during a measurement time interval by moving brake fluid via the at least one wheel inlet valve and/or via the at least one isolating valve into the at least one wheel brake cylinder.
- a second subunit 58 of electronic device 54 is designed and/or programmed, taking into account at least one volume variable determined during the measuring time interval and reflecting a current volume in the at least one wheel brake cylinder and at least one volume variable determined at the same time and reflecting a current pressure in the at least one wheel brake cylinder Pressure size to set a p-V- characteristic of at least one wheel brake cylinder. Examples of volume size, pressure size, and p-V characteristics are given above.
- the recorded pressure and volume signals are processed, for example, using a suitable data analysis program such as Matlab or Python.
- a third sub-unit 60 of the electronic device 54 can also be designed/programmed for the plausibility check and data processing of the specified p-V characteristic.
- a p-V characteristic curve can be calculated by the third sub-unit 60 by using a fitting curve.
- the finished p-V characteristic and/or intermediate values and parameters that are still required can be stored either in a volatile memory 62 or in a non-volatile memory 64 .
- the pV characteristic of the at least one wheel brake cylinder can be determined either by a manual trigger 66 or by a radio trigger 68 be started. A corresponding start signal 70 is then output to all sub-units 56, 58 and 60 of the control device 52.
- the p-V characteristic can be determined without irritating the driver.
- the determined p-V characteristic of the at least one wheel brake cylinder can then be output to at least one brake system controller 72.
- the determined p-V characteristic can also be displayed in the vehicle or transmitted to a workshop by radio.
- a common pressure build-up in all four wheel brake cylinders 10a to 10d can be effected by brake fluid being transferred into the four wheel brake cylinders 10a to 10d via at least the open wheel inlet valves 30a to 30d with the wheel outlet valves 32a to 32d closed.
- a sum of the p-V characteristics of the four wheel brake cylinders 10a to 10d is then compared with a specific p-V characteristic of all four wheel brake cylinders 10a to 10d, whereby a leak can be detected in one of the individual wheel measurements if there is a deviation.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US18/245,927 US20230382364A1 (en) | 2020-11-04 | 2021-10-25 | Control device and method for determining a p-v characteristic of at least one wheel brake cylinder of a brake system of a vehicle |
JP2023524321A JP2023547096A (ja) | 2020-11-04 | 2021-10-25 | 制御装置および車両のブレーキシステムの少なくとも1つの車輪ブレーキシリンダのp-V特性を決定するための方法 |
KR1020237018328A KR20230101847A (ko) | 2020-11-04 | 2021-10-25 | 차량의 브레이크 시스템의 적어도 하나의 휠 브레이크 실린더의 p-V 특성을 결정하기 위한 제어 장치 및 방법 |
CN202180074666.XA CN116390874A (zh) | 2020-11-04 | 2021-10-25 | 控制装置和为确定车辆制动系统至少一个车轮制动缸的p-V特性的方法 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE102020213860.5A DE102020213860A1 (de) | 2020-11-04 | 2020-11-04 | Steuervorrichtung und Verfahren zum Bestimmen einer p-V-Charakteristik zumindest eines Radbremszylinders eines Bremssystems eines Fahrzeugs |
DE102020213860.5 | 2020-11-04 |
Publications (1)
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WO2022096299A1 true WO2022096299A1 (de) | 2022-05-12 |
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PCT/EP2021/079483 WO2022096299A1 (de) | 2020-11-04 | 2021-10-25 | STEUERVORRICHTUNG UND VERFAHREN ZUM BESTIMMEN EINER p-V-CHARAKTERISTIK ZUMINDEST EINES RADBREMSZYLINDERS EINES BREMSSYSTEMS EINES FAHRZEUGS |
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US (1) | US20230382364A1 (de) |
JP (1) | JP2023547096A (de) |
KR (1) | KR20230101847A (de) |
CN (1) | CN116390874A (de) |
DE (1) | DE102020213860A1 (de) |
WO (1) | WO2022096299A1 (de) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102009028542A1 (de) * | 2009-08-14 | 2011-02-17 | Robert Bosch Gmbh | Verfahren und Vorrichtung zur Ansteuerung eines Bremssystems |
DE102013203189A1 (de) * | 2012-03-06 | 2013-09-12 | Continental Teves Ag & Co. Ohg | Verfahren zur Bestimmung einer Druck-Volumen-Kennlinie einer Radbremse |
DE102012210429A1 (de) * | 2012-06-20 | 2013-12-24 | Robert Bosch Gmbh | Verfahren zur Ermittlung der Druck-Volumencharakteristik von Fahrzeugbremsen |
DE102015204764A1 (de) * | 2015-03-17 | 2016-09-22 | Robert Bosch Gmbh | Verfahren zum Ermitteln einer Druck-Volumen-Charakteristik eines Bremssystems eines Fahrzeugs und Auswerte- und/oder Steuervorrichtung für zumindest eine Bremssystemkomponente eines Bremssystems eines Fahrzeugs |
-
2020
- 2020-11-04 DE DE102020213860.5A patent/DE102020213860A1/de active Pending
-
2021
- 2021-10-25 JP JP2023524321A patent/JP2023547096A/ja active Pending
- 2021-10-25 CN CN202180074666.XA patent/CN116390874A/zh active Pending
- 2021-10-25 WO PCT/EP2021/079483 patent/WO2022096299A1/de active Application Filing
- 2021-10-25 US US18/245,927 patent/US20230382364A1/en active Pending
- 2021-10-25 KR KR1020237018328A patent/KR20230101847A/ko unknown
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102009028542A1 (de) * | 2009-08-14 | 2011-02-17 | Robert Bosch Gmbh | Verfahren und Vorrichtung zur Ansteuerung eines Bremssystems |
DE102013203189A1 (de) * | 2012-03-06 | 2013-09-12 | Continental Teves Ag & Co. Ohg | Verfahren zur Bestimmung einer Druck-Volumen-Kennlinie einer Radbremse |
DE102012210429A1 (de) * | 2012-06-20 | 2013-12-24 | Robert Bosch Gmbh | Verfahren zur Ermittlung der Druck-Volumencharakteristik von Fahrzeugbremsen |
DE102015204764A1 (de) * | 2015-03-17 | 2016-09-22 | Robert Bosch Gmbh | Verfahren zum Ermitteln einer Druck-Volumen-Charakteristik eines Bremssystems eines Fahrzeugs und Auswerte- und/oder Steuervorrichtung für zumindest eine Bremssystemkomponente eines Bremssystems eines Fahrzeugs |
Also Published As
Publication number | Publication date |
---|---|
JP2023547096A (ja) | 2023-11-09 |
KR20230101847A (ko) | 2023-07-06 |
CN116390874A (zh) | 2023-07-04 |
US20230382364A1 (en) | 2023-11-30 |
DE102020213860A1 (de) | 2022-05-05 |
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