WO2021160298A1 - Système de freinage à sûreté intégrée - Google Patents

Système de freinage à sûreté intégrée Download PDF

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Publication number
WO2021160298A1
WO2021160298A1 PCT/EP2020/072284 EP2020072284W WO2021160298A1 WO 2021160298 A1 WO2021160298 A1 WO 2021160298A1 EP 2020072284 W EP2020072284 W EP 2020072284W WO 2021160298 A1 WO2021160298 A1 WO 2021160298A1
Authority
WO
WIPO (PCT)
Prior art keywords
seal
brake system
master cylinder
pressure chamber
simulator
Prior art date
Application number
PCT/EP2020/072284
Other languages
German (de)
English (en)
Inventor
Heinz Leiber
Thomas Leiber
Anton Van Zanten
Original Assignee
Ipgate Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from PCT/EP2020/053667 external-priority patent/WO2020165295A1/fr
Priority claimed from PCT/EP2020/053666 external-priority patent/WO2020165294A2/fr
Application filed by Ipgate Ag filed Critical Ipgate Ag
Priority to DE112020006702.5T priority Critical patent/DE112020006702A5/de
Publication of WO2021160298A1 publication Critical patent/WO2021160298A1/fr

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Classifications

    • 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
    • B60T13/12—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 the fluid being liquid
    • B60T13/14—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 the fluid being liquid using accumulators or reservoirs fed by pumps
    • 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
    • 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
    • B60T8/34—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 having a fluid pressure regulator responsive to a speed condition
    • B60T8/40—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 having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/4072—Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking
    • B60T8/4081—Systems with stroke simulating devices for driver input
    • 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
    • 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
    • B60T2270/413—Plausibility monitoring, cross check, redundancy

Definitions

  • the present invention relates to a hydraulic brake system which is protected against failures.
  • the requirements, especially safety requirements have a major influence on the design of a braking system and increase with the degree of automation (levels zero to five of the SAE J3016 standard) of the motor vehicle.
  • level one or higher e.g. for an adaptive cruise control
  • the braking force must be guaranteed even without the driver of a vehicle operating the brake pedal.
  • This requires at least one pressure supply device in a hydraulic brake system and a correspondingly designed electronic sensor and control unit.
  • the acceptance of defects also depends on the level of automation. In level two, individual errors are allowed if braking with at least approx. 0.3 g is possible, while in level three braking with at least approx. 0.5 g should be guaranteed in the case of individual errors.
  • ABS / ESP function must also be guaranteed in the event of a single fault.
  • double faults are accepted when the probability of failure based on ppm and FIT data is low. It is desirable if double faults with total brake failure do not occur.
  • the present invention relates to a brake system with two brake circuits. At least the requirements of level two according to the SAE J3016 standard are preferably met, with individual errors being able to be recognized in good time through redundancies and diagnoses, and double errors having an extremely low failure probability.
  • the invention relates to a brake system for a vehicle, comprising the following components: - At least one hydraulic brake circuit BK1, BK2 with at least one hydraulically acting wheel brake RB1, RB2, RB3, RB4;
  • At least one pressure supply device DV which is connected to a brake circuit BK1, BK2 via a hydraulic line;
  • a hydraulic brake pedal system with a master cylinder with at least one pressure chamber, of which a hydraulic output is switchably coupled to at least one brake circuit BK1, BK2 via a feed switching valve FV, and wherein the master cylinder is coupled to a reservoir VB via at least one opening via a hydraulic connection is; optionally where a failure of a pressure chamber seal of the at least one pressure chamber of the master cylinder is secured by at least one redundancy and where the failure of the pressure chamber seal or the redundancy of the pressure chamber seal of the at least one pressure chamber of the master cylinder can be diagnosed.
  • Aspect 2 Brake system according to aspect 1, further comprising a switching valve SV1, SV2, SV3, SV4 for each hydraulically acting wheel brake RB1, RB2, RB3, RB4, which each have a hydraulically acting wheel brake RB1, RB2, RB3, RB4 with one of the two brake circuits BK1 , BK2 switchable connects.
  • a switching valve SV1, SV2, SV3, SV4 for each hydraulically acting wheel brake RB1, RB2, RB3, RB4 which each have a hydraulically acting wheel brake RB1, RB2, RB3, RB4 with one of the two brake circuits BK1 , BK2 switchable connects.
  • Aspect 3 Brake system according to aspect 1 or 2, further comprising at least one hydraulic connection between the two brake circuits BK1, BK2 that can be switched via at least one bypass switching valve BPI.
  • Aspect 4 Brake system according to one of the preceding aspects, wherein the brake system has a single master cylinder SHZ.
  • Aspect 5 Brake system according to one of the preceding aspects, wherein the brake system has a control and regulating unit ECU.
  • Aspect 6 Brake system according to one of the preceding aspects, wherein the master cylinder has a force travel sensor KWS for determining the pedal force and / or wherein the master cylinder has a pressure transducer for sensing the pressure in at least one pressure chamber of the master cylinder, the brake system optionally having at least one pedal travel sensor Spl, Sp2 having.
  • Aspect 7 Brake system according to one of the preceding aspects, wherein at least one pressure chamber 4a of the hydraulic brake pedal system is connected to a travel simulator pressure chamber WSD of a travel simulator WS via a hydraulic valve circuit.
  • Aspect 8 Brake system according to aspect 7, wherein the at least one pressure chamber 4a of the hydraulic brake pedal system is connected to the path simulator pressure chamber WSD in the path simulator WS via a parallel connection of a check valve RV2 closing towards the path simulator WS and a second throttle Dr2.
  • Aspect 9 Brake system according to aspect 7 or 8, wherein a failure of a pressure chamber seal of the path simulator pressure chamber WSD is secured by at least one further redundancy and the failure of the pressure chamber seal of the path simulator pressure chamber WSD or the redundancy of the pressure chamber seal of the path simulator pressure chamber WSD can be diagnosed.
  • Aspect 10 Brake system according to one of aspects 7 to 9, the travel simulator WS having a travel simulator piston WSK.
  • Aspect 11 Brake system according to aspect 10, wherein the travel simulator piston WSK has at least one recess B7, which connects the travel simulator pressure chamber WSD to the travel simulator housing WSG via at least one opening cross-section in the outer surface of the travel simulator piston WSK.
  • Aspect 12 Brake system according to aspect 10 or 11, wherein the path simulator piston WSK has at least one redundant recess B7r, which connects a path simulator empty space WSL in the path simulator WS via at least one further opening cross-section in the outer surface of the path simulator piston WSK with the path simulator housing WSG.
  • Aspect 13 Brake system according to aspect 11 or 12, wherein the recess B7 or the recesses in the travel simulator piston WSK represent a third throttle Dr3.
  • Aspect 14 Brake system according to one of aspects 12 to 13, wherein the redundant cutout B7r or the redundant cutouts in the travel simulator piston WSK represent a third redundant throttle Dr3r.
  • Aspect 15 Brake system according to one of aspects 10 to 14, wherein the path simulator housing WSG has at least one first path simulator seal D3, which serves to seal the path simulator pressure chamber WSD, in particular wherein the at least first path simulator seal D3 in a pressureless starting position of the path simulator piston WSK, the path simulator pressure chamber WSD against the WSL seals off path simulator empty space.
  • Aspect 16 Brake system according to one of aspects 10 to 15, wherein the travel simulator housing WSG has at least one second travel simulator seal D3r, which the Pressure chamber sealing of the path simulator pressure chamber WSD is used, in particular wherein the at least one second path simulator seal D3r seals the path simulator pressure chamber WSD from the path simulator empty space WSL from a certain position of the path simulator piston WSK.
  • Aspect 17 Brake system according to aspect 16, if dependent on aspects 11, 12 and 15, wherein the at least one recess B7 and the at least one redundant recess B7r are arranged in the travel simulator piston WSK in such a way that the at least one opening cross-section is not in any position of the travel simulator piston WSK in the outer surface of the travel simulator piston WSK for the at least one recess B7 and the at least one further opening cross-section in the outer surface of the travel simulator piston WSK for the at least one redundant recess B7r are located between the at least first travel simulator seal D3 and the at least second travel simulator seal D3r.
  • Aspect 18 Brake system according to aspect 17, wherein the first travel simulator seal D3 and the second travel simulator seal D3r are arranged in such a way and the brake system is designed in such a way that for vehicle decelerations greater than 0.5m / s 2 , 0.6m / s 2 , 0.7m / s 2 , 0.8m / s 2 , 0.9m / s 2 , 1.0m / s 2 , 1.1m / s 2 , 1.2m / s 2 , 1.3m / s 2 , 1.4m / s 2 or 1.5m / s 2 the minimum a recess B7 of the travel simulator piston WSK is located between the at least one first travel simulator seal D3 and the at least one second travel simulator seal D3r.
  • Aspect 19 Brake system according to aspect 17 or 18, wherein the at least one first travel simulator seal D3 and the at least one second travel simulator seal D3r are the pressure chamber seal of the travel simulator pressure chamber WSD.
  • Aspect 20 Brake system according to one of aspects 17 to 19, wherein the first travel simulator seal D3 is the pressure chamber seal of the travel simulator pressure chamber WSD if the at least one redundant recess B7r is located between the at least one first travel simulator seal D3 and the at least one second travel simulator seal D3r.
  • Aspect 21 Brake system according to one of aspects 17 to 20, wherein the second travel simulator seal D3r is the pressure chamber seal of the travel simulator pressure chamber WSD when the at least one recess B7 is located between the at least one first travel simulator seal D3 and the at least one second travel simulator seal D3r.
  • Aspect 22 Brake system according to one of aspects 17 to 21, with a leaky first travel simulator seal D3 and a tight second travel simulator seal D3r a throttled leakage flow from the travel simulator pressure chamber WSD via the at least one recess B7 and an annular gap in a rear area between the travel simulator piston WSK and the Path simulator housing WSG and via the at least one redundant recess B7r into the path simulator empty space WSL if the at least one redundant recess B7r is located between the at least one first path simulator seal D3 and the at least one second path simulator seal D3r, with the rear area facing the path simulator pressure chamber WSD Area is meant.
  • Aspect 23 Brake system according to one of aspects 17 to 22, with a tight first travel simulator seal D3 and a leaky second travel simulator seal D3r a throttled leakage flow from the travel simulator pressure chamber WSD via the at least one recess B7 and via the at least one redundant recess B7r and a further annular gap in a front area between the path simulator piston WSK and the path simulator housing WSG into the path simulator empty space WSL if the at least one recess B7 is located between the at least one first path simulator seal D3 and the at least one second path simulator seal D3r, with the front area facing the path simulator empty space WSL Area is meant.
  • Aspect 24 Brake system according to one of aspects 17 to 23, the leakage caused by a leaky first path simulator seal D3 or a leaky second path simulator seal D3r from the path simulator pressure chamber WSD into the path simulator empty space WSL is throttled in such a way that, on the one hand, a pedal force-path characteristic is reversed shifts no more than 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm and on the other hand the leakage can be diagnosed.
  • Aspect 25 Brake system according to one of Aspects 17 to 24, wherein the third throttle Dr3 and the third redundant throttle Dr3r have different hydraulic resistances.
  • Aspect 26 Brake system according to one of aspects 17 to 25, wherein the control and regulating unit ECU is adapted to diagnose the failure of the first travel simulator seal D3 and / or the failure of the second travel simulator seal D3r, optionally using the pressure supply device DV.
  • Aspect 27 Brake system according to aspect 26, wherein the force travel sensor KWS is not used for diagnosis.
  • Aspect 28 Brake system according to one of aspects 17 to 27, wherein the control and regulation unit ECU is adapted to the failure of the first travel simulator seal D3 and / or the failure of the second travel simulator seal D3r using the force travel sensor KWS and / or the pressure transducer diagnose.
  • Aspect 29 Brake system according to one of the preceding aspects, wherein the opening is sealed by at least one primary seal D2 and optionally at least one secondary seal D1.
  • Aspect 30 Brake system according to one of the preceding aspects, the hydraulic connection having a parallel connection of a throttle Drl and a check valve RV1 closing towards the reservoir VB.
  • Aspect 31 Brake system according to aspect 29 or 30, wherein the primary seal D2 is the pressure chamber seal of the at least one pressure chamber of the master cylinder.
  • Aspect 32 Brake system according to one of aspects 29 to 31, the control and regulation unit ECU being adapted to diagnose the failure of the primary seal D2 using the force displacement sensor KWS and / or the pressure transducer.
  • Aspect 33 Brake system according to one of aspects 30 to 32, if dependent on aspect 30, wherein the throttle Drl and the non-return valve RV1 closing towards the reservoir VB are the redundancy of the pressure chamber seal of the at least one pressure chamber of the master cylinder.
  • Aspect 34 Brake system according to aspect 33, wherein the control and regulating unit ECU is adapted to diagnose the failure of the redundancy of the pressure chamber seal, optionally using the pressure supply device DV.
  • Aspect 35 Brake system according to one of aspects 29 to 34, the control and regulation unit ECU being adapted to diagnose a failure of the secondary seal Dl, optionally using the pressure supply device DV.
  • Aspect 36 Brake system according to one of the preceding aspects, wherein the storage container VB has a level sensor via which the fill level of the storage container can be detected.
  • Aspect 37 Brake system according to aspect 36, wherein a failure of the secondary seal Dl can be diagnosed via the level sensor of the storage container VB, in particular as part of maintenance, during which a pressure of, for example, approximately 5 bar is generated in the storage container VB.
  • Aspect 38 Brake system according to one of Aspects 34 to 37, wherein the force travel sensor KWS is not used for diagnosis.
  • Aspect 39 Brake system according to one of the preceding aspects, wherein the master cylinder has at least one secondary seal Dir which is redundant to the secondary seal D1.
  • Aspect 40 Brake system according to aspect 39, wherein the master cylinder has a further opening between the secondary seal Dl and the redundant secondary seal Dir, which is connected to the reservoir VB via a further throttle Dr4.
  • Aspect 41 Brake system according to one of the preceding aspects, wherein the master cylinder has at least one primary seal D2r which is redundant to the primary seal D2 and which serves to seal the pressure chamber.
  • Aspect 42 Brake system according to one of aspects 39 to 41, the hydraulic connection having a valve VD which shuts off above a predetermined limit volume flow in the direction of flow from the master cylinder to the reservoir VB and is always open in the counterflow direction.
  • Aspect 43 Brake system according to aspect 41 or 42, wherein the control and regulating unit ECU is adapted to diagnose a failure of the redundant primary seal D2r using the force travel sensor KWS and / or the pressure transducer.
  • Aspect 44 Brake system according to aspect 42 or 43, wherein the control and regulating unit ECU is adapted to diagnose a failure of the valve VD ZU, optionally using the pressure supply device DV.
  • Aspect 45 Brake system according to one of the preceding aspects, the hydraulic connection having a switchable solenoid valve 17.
  • Aspect 46 Brake system according to aspect 45, wherein the master cylinder has at least one redundant primary seal D2r, the master cylinder having at least one further opening between the at least one redundant primary seal D2r and the at least one primary seal D2, which can also be switched via the switchable solenoid valve 17 with the Reservoir VB is connected.
  • Aspect 47 Brake system according to aspect 45 or 46, wherein the master cylinder between the at least one redundant secondary seal Dir and the at least one secondary seal Dl has at least one further opening which is connected to the reservoir VB via a further throttle Dr4.
  • Aspect 48 Brake system according to one of aspects 45 to 47, the control and regulation unit ECU being adapted to diagnose a failure of the switchable solenoid valve 17 using the force displacement sensor KWS.
  • Aspect 49 Brake system according to one of aspects 45 to 47, the control and regulating unit ECU being adapted to diagnose a failure of the switchable solenoid valve 17, optionally using the pressure supply device DV, the force displacement sensor KWS not being used for diagnosis.
  • Aspect 50 Brake system according to aspect 29, wherein the hydraulic connection has a parallel connection of a throttle Drla and a non-return valve RV1 closing towards the reservoir VB.
  • Aspect 51 Brake system according to aspect 50, wherein the master cylinder has at least one primary seal D2r redundant to the primary seal D2, the master cylinder having at least one further opening B2 between the at least one redundant primary seal D2r and the at least one primary seal D2, which via a further throttle Drl is connected to the reservoir VB.
  • Aspect 52 Brake system according to aspect 51, wherein the redundant primary seal D2r is the pressure chamber seal of the at least one pressure chamber 4a of the master cylinder.
  • Aspect 53 Brake system according to aspect 51 or 52, wherein the further throttle Drl has a hydraulic resistance which, in the event of a leaky redundant primary seal D2r and a tight primary seal D2, is on the one hand so great that a pedal force-travel characteristic is not more than 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm and on the other hand is so small that the leakage can be diagnosed by the further throttle Drl.
  • the further throttle Drl has a hydraulic resistance which, in the event of a leaky redundant primary seal D2r and a tight primary seal D2, is on the one hand so great that a pedal force-travel characteristic is not more than 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm and on the other hand is so small that the leakage can be diagnosed by the further throttle Drl.
  • Aspect 54 Brake system according to one of aspects 51 to 53, wherein the further throttle Drl is the redundancy of the pressure chamber seal of the at least one pressure chamber of the master cylinder.
  • Aspect 55 Brake system according to one of aspects 50 to 54, wherein the throttle Drla has a lower hydraulic resistance than the further throttle Drl.
  • Aspect 56 Brake system according to one of aspects 51 to 55, with a leaky primary seal D2 and leaky redundant primary seal D2r, the feed switching valve FV can be opened completely, partially or pulsed and a dynamic pressure via volume delivery of the at least one pressure supply device DV and via the throttle Drla can be generated in the pressure chamber 4a of the master cylinder, which counteracts a failure of the brake pedal 1.
  • Aspect 57 Brake system according to aspect 29, wherein the hydraulic connection of the opening of the master cylinder to the reservoir VB consists only of one line and in particular does not contain any valves or throttles.
  • Aspect 58 Brake system according to aspect 57, wherein the master cylinder has at least one primary seal D2r redundant to the primary seal D2, the master cylinder having at least one further opening between the at least one redundant primary seal D2r and the at least one primary seal D2, which is connected to the reservoir via a throttle VB is connected.
  • Aspect 59 Brake system according to aspect 58, wherein the redundant primary seal D2r is the pressure chamber seal of the at least one pressure chamber of the master cylinder.
  • Aspect 60 Brake system according to aspect 58 or 59, wherein the throttle has a hydraulic resistance which, in the event of a leaky redundant primary seal D2r and a tight primary seal D2, is on the one hand so large that a pedal force-travel characteristic does not change by more than 0.1mm, 0.2mm , 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm, and on the other hand is so small that the leakage through the throttle can be diagnosed.
  • Aspect 61 Brake system according to one of aspects 58 to 60, wherein the throttle is the redundancy of the pressure chamber seal of the at least one pressure chamber of the master cylinder.
  • Aspect 62 Brake system according to one of aspects 51 to 56 or 58 to 61, the control and regulation unit ECU being adapted to diagnose the failure of the redundant primary seal D2r using the force displacement sensor KWS and / or the pressure transducer.
  • Aspect 63 Brake system according to aspect 62, wherein the force travel sensor KWS is not used for diagnosis.
  • Aspect 64 Brake system according to one of aspects 17 to 63, with a hydraulic resistance of the throttle Drl acting as redundancy for the pressure chamber sealing in the connection to the master cylinder on the reservoir VB and the hydraulic resistances of the throttles Dr3, Dr3r of the cutouts and redundant cutouts of the path simulator WS are designed in such a way that a leak can be assigned either to the pressure chamber seal D2, D2r of the master cylinder or to the travel simulator seal D3, D3r.
  • Aspect 65 Brake system according to one of aspects 17 to 64, wherein a hydraulic resistance of the throttle Drl acting as redundancy for the pressure chamber seal in the Connection to the master cylinder on the reservoir VB, a hydraulic resistance of the throttle Dr3 of the at least one recess and a hydraulic resistance of the further throttle Dr3r of the at least one redundant recess of the path simulator WS are designed in such a way that a leak in the pressure chamber seal D2, D2r of the master cylinder, the first path simulator seal D3 or the second path simulator seal D3r can be assigned, optionally the vehicle deceleration can be taken into account.
  • Aspect 66 Brake system according to one of the preceding aspects, wherein each hydraulically acting wheel brake RB1, RB2, RB3, RB4 is assigned a switchable inlet valve EV, and wherein the switching valves AV are connected to the reservoir VB for each hydraulically acting wheel brake RB1, RB2, RB3, RB4 is.
  • Aspect 67 Brake system according to one of the preceding aspects, wherein the brake system furthermore has at least one hydraulic connection, switchable via at least one outlet switching valve ZAV, between at least one of the brake circuits BK1, BK2 and the reservoir VB.
  • Aspect 68 Brake system according to aspect 67, wherein the pressure is reduced in the at least one hydraulically acting wheel brake RB1, RB2, RB3, RB4 by opening the outlet switching valve ZAV and the associated switching valve SV1, SV2, SV3, SV4.
  • Aspect 69 Brake system according to aspect 67 or 68, wherein the two hydraulic brake circuits BK1, BK2 are connected to one another via the bypass switching valve BPI and a further bypass switching valve BP2, which are connected in series, the outlet switching valve ZAV with a line section between the two bypass switching valves BPI, BP2 is connected.
  • Aspect 70 Brake system according to one of the preceding aspects, wherein the pressure reduction in the at least one hydraulically acting wheel brake RB1, RB2, RB3, RB4 can take place via the master cylinder.
  • Aspect 71 Brake system according to one of the preceding aspects, wherein the brake system has a first return spring RF 1 and optionally a second return spring RF2, wherein the second return spring RF2 counteracts a possible pedal failure.
  • Aspect 72 Brake system according to one of the preceding aspects, the at least one pressure chamber of the master cylinder being connected to the feed switching valve FV via an interposed back pressure valve 19.
  • Aspect 73 Brake system according to aspect 72, wherein the back pressure valve 19 at pressures above a predetermined pressure, which from the master cylinder in the direction of the feed switching valve FV go out, acts as a throttle in the direction of the feed switching valve FV and does not exert any significant throttling effect in the opposite direction.
  • Aspect 74 Brake system according to one of the preceding aspects, the brake system having at least two hydraulic brake circuits BK1, BK2.
  • Aspect 75 Brake system according to one of the preceding aspects, wherein a brake pedal 1 of the hydraulic brake pedal system acts on a master cylinder piston 3 in the master cylinder via an intermediate tappet 2a and a spring FKWS.
  • Aspect 76 Brake system according to one of the preceding aspects, wherein the master cylinder has at least one travel sensor Spl for detecting the engagement travel of the master cylinder piston 3.
  • Aspect 77 Brake system according to one of the preceding aspects, the master cylinder having at least one further travel sensor Sp2 for detecting the engagement travel of the intermediate tappet 2a.
  • Aspect 78 Brake system according to one of the preceding aspects, the master cylinder having a redundant displacement sensor Spl.l for detecting the engagement path of the master cylinder piston 3 and a further redundant displacement sensor Sp2.1 for detecting the engagement path of the intermediate tappet 2a.
  • Aspect 79 Brake system according to one of the preceding aspects, wherein a pedal force is calculated from the difference in the engagement paths of master cylinder piston 3 and intermediate tappet 2a and a force-displacement characteristic of the spring FKWS between master cylinder piston 3 and intermediate tappet 2a.
  • Fig. La shows a first possible embodiment of the brake system according to the invention in a minimal valve arrangement in the HCU with a bypass switching valve BPI and a central outlet switching valve ZAV.
  • Fig. Lb shows a second possible embodiment of the brake system according to the invention in an expanded valve arrangement in the HCE1 with two bypass switching valves (BPI and BP2), two (central) outlet switching valves (ZAV1, ZAV2), and a separating valve TV.
  • Fig. 2 shows the structure of a diagnostic valve V D.
  • Fig. 3a shows an embodiment according to the invention for the connection between the single master cylinder and the storage container VB with two throttles (Drl, Dr4) and a check valve RV1 and a redundant secondary di rectification Dir.
  • 3b shows an embodiment according to the invention for the connection between the individual master cylinder and the storage container VB with diagnostic valve VD and a redundant one
  • 3c shows an embodiment according to the invention for the connection between the individual master cylinder and the storage container VB with a storage container shut-off valve 17, a throttle Dr4 and a redundant primary D2r and secondary seal Dir with another return spring RF2 and a path simulator WS.
  • FIG. 3e shows an embodiment according to the invention for the connection between the individual master cylinder and the storage container VB with two throttles (Drl, Dr4) and a check valve RV1 and a redundant primary seal D2r.
  • FIG. 3e shows an embodiment according to the invention of a travel simulator WS with two seals (D3, D3r), a travel simulator piston WSK with two recesses (B7, B7r) and two throttles (Dr3, Dr3r).
  • Fig. 3e details the force travel sensor system with redundant pedal travel sensors Spl.l, Sp2.1.
  • FIG. 4a shows an embodiment according to the invention with a single master cylinder unit SHZ and a two-circuit double-stroke piston pump with four check valves (RV3, RV4, RV5, RV6).
  • FIG. 4b shows an embodiment according to the invention with a single master cylinder unit SHZ and a two-circuit double-stroke piston pump with three check valves (RV4, RV5, RV6) and a solenoid valve PD1.
  • Fig. 4c shows an embodiment with a single master cylinder unit SHZ and a two-circuit double piston pump with four solenoid valves (PD1, PD2, PD3, PD4).
  • 5a shows an embodiment according to the invention with a conventional tandem master cylinder unit THZ and a two-circuit double-stroke piston pump with four check valves (RV3, RV4, RV5, RV6).
  • 5b shows an embodiment according to the invention with a tandem master cylinder unit THZ with a tappet and a two-circuit double-stroke piston pump with four check valves (RV3, RV4, RV5, RV6).
  • Fig. La shows elements of a hydraulic brake system with a single master cylinder unit SHZ with brake pedal 1, single master cylinder and reservoir VB of a pressure supply device DV, an electronic control unit ECU and a (not shown) wheel brake RB1, RB2, RB3, RB4 each with a wheel cylinder RZ1, RZ2, RZ3, RZ4.
  • Two wheel cylinders RZ1, RZ2 are each connected to a first brake circuit BK1 via a switching valve SV1, SV2 and a further two wheel cylinders RZ3, RZ4 are each connected to a second brake circuit BK2 via a switching valve SV3, SV4.
  • two or more switching valves can also be provided per wheel cylinder.
  • the pressure supply device DV comprises a pump and a brushless direct current motor, which optionally has a redundant winding and / or is connected to the electronic control unit ECU via 2 ⁇ 3 phases.
  • the pump can be a plunger pump (not shown) with a spindle drive or a rotary pump, whereby the rotary pump can in turn be designed as a multi-piston pump (eg as a three-piston pump) or as a gear pump.
  • the pressure supply device DV can be connected to the first brake circuit BK1 via a check valve RV3 closing towards the pressure supply device DV.
  • the pressure supply device DV can be connected directly (without RV3) to the first brake circuit BK1.
  • One or more check valves can be integrated in the multi-piston pump.
  • a solenoid valve (not shown) is required instead of the check valve RV3.
  • the plunger or rotary pump can be connected to the storage container VB.
  • the two brake circuits (BK1 and BK2) are connected via a switchable bypass switching valve BPI.
  • the second brake circuit BK2 is connected to the reservoir VB via a switchable central outlet switching valve ZAV and to a hydraulic output of the pressure chamber of the individual master cylinder via a switchable feed switching valve FV.
  • a double master cylinder with a corresponding connection such as, for example, in FIG. 5a or FIG. 5b, can also be used for additional increased security.
  • the pressure in one of the two brake circuits e.g. BK2 can be measured by a pressure sensor (e.g. DG) on this brake circuit (e.g. BK2) and transferred to the ECU.
  • a pressure sensor e.g. DG
  • further pressures in the brake circuits e.g. BK1
  • further pressures in the brake circuits e.g. BK1 can be measured via further pressure sensors (e.g. DG2) and transferred to the ECU.
  • the hydraulic system with the wheel cylinders RZ1, RZ2, RZ3, RZ4, the switching valves SV1, SV2, SV3, SV4, the two brake circuits BK1, BK2, the pressure sensors (DG1, DG2), the bypass switching valve BPI, the central outlet switching valve ZAV, the The pressure supply device DV and, if present, the check valve RV3 can be combined in a so-called hydraulic control unit HCU.
  • the hydraulic control unit HCU has just one pressure supply DV.
  • a travel simulator WS with or without a switchable travel simulator isolating valve 14 can also be connected to a further hydraulic output of the individual master cylinder (or to the hydraulic line between the feed switching valve FV and the individual master cylinder).
  • the travel simulator can transmit a certain pedal travel force characteristic to the brake pedal 1 via a slave piston, which can be disengaged against an arrangement of return springs by pressing the foot on the brake pedal 1, for example.
  • the hydraulic connection of the path simulator WS to the individual master cylinder can, as shown in Fig. La, e.g. via a parallel connection with a throttle Dr2 and a check valve RV2 or in another way.
  • the pedal movement can be reduced when pressure is built up via throttle Dr2 and when the path simulator WS is emptied, the throttle Dr2 can be bypassed via the check valve RV2.
  • the coupling takes place as "brake-by-wire" via the redundant pedal travel sensors, the ECU and the pressure supply device DV, which when the switching valves SV1, SV2, SV3, SV4 are open, the bypass switching valve BPI is open and the central outlet switching valve ZAV is closed from the brake fluid volume Feed reservoir VB into the wheel cylinders RZ1, RZ2, RZ3, RZ4 of both brake circuits BK1, BK2 and thereby build up brake pressure.
  • the bypass switching valve BPI can also be closed during regular braking if only the wheel cylinders RZ1, RZ2 in the first brake circuit BK1 are to be used for braking.
  • a target pressure can be regulated as a function of the pedal travel via the at least one pressure sensor DG in one of the brake circuits BK1, BK2, and / or pulse width modulation of the switching valves SV1, SV2, SV3, SV4 and / or the bypass valve BPI.
  • the driver Via the travel simulator WS and the return spring RF in the individual master cylinder, the driver receives a certain pedal travel force characteristic, which can preferably always be the same as possible and independent of the brake pressures in the brake circuits BK1, BK2.
  • the combination of travel simulator WS and restoring spring RF in the “brake-by-wire” system counteracts the breakdown of the brake pedal and brings the pedal back into a defined starting position after the foot is pressed.
  • the recovery of braking energy (recuperation) in the electric traction motors can thus be decoupled from the brake pedal 1.
  • the pedal travel force characteristic is not influenced even in the non-regular case, for example in the event of a brake circuit failure.
  • the central outlet switching valve ZAV can be opened, especially when using a rotary pump.
  • the switching valves SV1, SV2, SV3, SV4 and / or the bypass switching valves BPI, BP2 are completely or depending on the desired pressure reduction gradient via pulse width modulation (PWM) or short stops (e.g. after a time At or after a differential pressure Dr) or otherwise opened.
  • PWM pulse width modulation
  • Dr differential pressure
  • the exchange of brake fluid between the pressure chamber of the individual master cylinder and the reservoir VB can take place through, for example, radial sniffing openings in the piston 3 and in the individual master cylinder as well as via a hydraulic connection.
  • This hydraulic connection can take place, as in FIG. 1 a, by a parallel connection of a throttle Drl and a check valve RV1 or in some other way.
  • the pressure chamber in the individual master cylinder can be sealed using a primary seal D2 and a secondary seal Dl and other redundant seals, not shown, with the primary seal D2 in particular being attached in the individual master cylinder or on the piston 3 of the individual master cylinder.
  • ABS is the following: the controller signals during pressure build-P in that a brake cylinder (eg RZ1) of a wheel, for example the criterion of met too much brake pressure, the pressure build up P may be stopped on the observation of the wheel or (optionally after such an observation time) the brake pressure can be reduced by reducing the pressure P ab. Since the feed switching valve FV remains closed and, depending on the design, the pump cannot take up any volume from the brake circuits in the pressure supply device DV, opening the central outlet switching valve ZAV is the only possible way of reducing pressure P ab .
  • a brake cylinder eg RZ1
  • the pressure build up P may be stopped on the observation of the wheel or (optionally after such an observation time) the brake pressure can be reduced by reducing the pressure P ab. Since the feed switching valve FV remains closed and, depending on the design, the pump cannot take up any volume from the brake circuits in the pressure supply device DV, opening the central outlet switching valve ZAV is the only possible way of reducing pressure P ab .
  • braking can also be carried out by the driver via the pressure supply device DV without the driver having to operate the pedal, with the brake pedal 1 being controlled by the then closed feed switching valve FV Engagement is hydraulically decoupled.
  • the “brake-by-wire” braking system according to the invention with path simulator WS, electromotive pressure supply device DV and ABS / ESP functionality can be referred to as a so-called one-box system. Due to the high degree of integration of such a one-box system, the installation space, weight and costs of the entire structural unit can be reduced and installation and logistics can also be optimized.
  • the valves FV, BPI, SV1, SV2, SV3, SV4 can be designed as normally open solenoid valves, while the valves ZA V and, if present, the travel simulator isolating valve 14 are preferably normally closed solenoid valves.
  • the switching valves SV1, SV2, SV3, SV4 are preferably connected via their output side to the respective wheel cylinders RZ1, RZ2, RZ3, RZ4, so that each switching valve SV1, SV2, SV3, SV4 in the event of a fault, e.g. if its electrical connection fails the pressure in the respective wheel cylinder RZ1, RZ2, RZ3, RZ4 opens itself.
  • This valve configuration can in particular ensure that if there is no power supply, the brake pedal 1 can be hydraulically coupled to the wheel cylinders RZ1, RZ2, RZ3, RZ4 via the open feed switching valve FV and brake pressure can be built up. If the path simulator isolating valve 14, which is closed when deenergized, is present, the path simulator WS can also be decoupled from the brake pedal 1, as a result of which, for example, approx. 40% pedal travel can be saved.
  • All solenoid valves in particular the ZAV, can each be designed as a redundant valve and / or with a redundant coil and / or with redundant control, whereby the probability of a valve failure can be reduced.
  • valves FV, BPI, SV1, SV2, SV3, SV4 can be opened and the valves ZAV and, if present, the travel simulator isolating valve 14 can be closed so that brake pressure can be built up by actuating the brake pedal.
  • the bypass switching valve BPI can be closed and sufficient brake pressure can be built up in the second brake circuit BK2 by pressing the brake pedal 1.
  • the brake system can have various sensors, in particular pressure sensors DG, DG2, redundant pedal travel sensors (Spl and Sp2) for determining the pedal travel, a force travel sensor KWS in the piston of the individual master cylinder for determining a force-pedal travel characteristic, a level sensor element 6 for determining the level of the Have brake fluid in the reservoir VB, a yaw rate sensor GWS for ESP interventions, for example, or other sensors (for example a temperature sensor), the sensor values of which can be transmitted to the electronic control unit ECU.
  • sensors DG, DG2, redundant pedal travel sensors (Spl and Sp2) for determining the pedal travel
  • a force travel sensor KWS in the piston of the individual master cylinder for determining a force-pedal travel characteristic
  • a level sensor element 6 for determining the level of the Have brake fluid in the reservoir VB
  • GWS for ESP interventions
  • other sensors for example a temperature sensor
  • a pressure sensor (not shown) can be integrated into the individual master cylinder, which can detect the pressure in the pressure chamber and transmit it to the ECU.
  • all solenoid valves in particular valves SV1, SV2, SV3, SV4, BPI, ZAV, FV, 14, can be switched by the electronic control unit ECU, preferably via a redundant electronic control or via a redundant coil.
  • the electronic control unit ECU can be attached to the hydraulic control unit HCU and preferably connected to the vehicle's electrical system via a connector 13, with bus communication being implemented, for example, via FlexRay or CAN or in some other way can.
  • the redundant pedal travel sensors can be implemented in different ways.
  • two sensor rods are moved by an extension of the single master cylinder piston 3, which act on the redundant pedal travel sensors (Spl and Sp2).
  • 3 locking elements can be accommodated in an extension of the piston.
  • the redundant pedal travel sensors (Spl and Sp2) can also be coupled with two pistons and a spring between the two pistons. This has the advantage that it can be used to measure the force displacement with additional advantages in error analysis, e.g. with regard to a jammed piston 3, see also DE102010050132.
  • a loss of braking force caused by a leaky seal in one of the wheel cylinders RZ1, RZ2, RZ3, RZ4 can be determined by a comparison with a predetermined pressure-volume characteristic for the pressure build-up P, which depends on various boundary conditions such as valve positions, temperature, ventilation of the brake system , Clearance of the wheel brakes RB1, RB2, RB3, RB4 etc. can depend on the additional loss volume uptake or the additional volume delivery of the pressure supply device DV can be recognized.
  • the wheel cylinder in which the loss of braking force occurs can be localized via the following diagnosis: After the pressure P up has been built up , all switching valves SV1, SV2, SV3, SV4 are open and the pressure supply device DV does not continue to operate if there is residual pressure in the brake circuits BK1, BK2 energized. After closing the bypass switching valve BPI, the pressure measured by the pressure sensor DG in the second brake circuit BK2 can be examined. If the pressure drops, wheel cylinders RZ3 and / or RZ4 must be leaking. By closing switching valve SV3, for example, a leak in the wheel cylinder RZ4 can be detected when the pressure drops, or a leak in the wheel cylinder RZ3 when the pressure is constant.
  • the wheel cylinders RZ3 and RZ4 can be recognized as tight.
  • the bypass switching valve BPI is opened and the switching valves SV1, SV3 and SV4 are closed. If the pressure drops, the leak in the wheel cylinder RZ2 can be detected, while at constant pressure the leak in the wheel cylinder RZ1 can be detected.
  • the associated switching valve e.g. SV1 can be closed before each braking operation until the unit is replaced in the service department, so that two or three wheel cylinders (e.g.
  • RZ2, RZ3, RZ4) with reduced but sufficient braking force can be decelerated for level two of autonomous driving. If a slight leakage is found in a wheel cylinder as described above, the leakage can be compensated for by means of replenishment via the pressure supply device DV as an alternative to shutting down the wheel cylinder.
  • the tightness of the central outlet switching valve ZAV and the feed switching valve FV can be checked, preferably at standstill with or without volume delivery via the pressure supply device DV, with alternately closed and opened valves ZAV and FV. If a possible leak can be localized, for example, via a pressure oscillation from the pressure supply device DV and an interaction between the level sensor element 6 in the storage container VB and pedal movement in the ZAV or FV, the following measures can be distinguished: In the case of a blockage, e.g.
  • the bypass switching valve BPI the switching valves SV3 and SV4 in the second brake circuit BK2 and the central outlet switching valve ZAV can be closed, whereby the leakage of the feed switching valve FV in principle Possible detuning of the pedal characteristics in the individual master cylinder can be prevented and sufficient brake pressure can still be built up in the first brake circuit BK1 via the pressure supply device DV.
  • the same procedure can be used as in the case of a leak at FV.
  • the bypass switching valve BPI can be closed and is still sufficient via the pressure supply device DV in the first brake circuit BK1 Braking force, especially for level two in autonomous driving, can be built up.
  • the so-called diagonal distribution of the braking force on the four wheels of the vehicle can be particularly advantageous, which leads to greater braking compared to the distribution of the brake circuits BK1, BK2 on the front and rear axles of the vehicle can (e.g. approx. 50% with the diagonal division compared to approx.
  • Diagonal distribution of the braking force means that a brake circuit has a front brake on one side of the vehicle and the rear brake assigned to the other side of the vehicle.
  • the wheel brakes of the other diagonals are correspondingly assigned to the second brake circuit.
  • the bypass switching valve BPI can be closed and the feed switching valve FV opened so that the Brake pedal 1 still sufficient brake pressure can be built up in the second brake circuit BK2.
  • the travel simulator isolating valve 14 can also be closed, whereby e.g. approx. 40% pedal travel can be saved.
  • the second brake circuit can be decoupled by closing the switching valves SV3 and SV4, the central outlet switching valve ZAV, and the bypass switching valve BPI. Since a detuning of the pedal travel characteristic in the individual master cylinder can be prevented in this way, sufficient brake pressure can still be built up in the first brake circuit BK1 via the pressure supply device DV.
  • the braking force in the wheel brakes RB1, RB2, RB3, RB4 can be further increased by pressing the brake pedal 1 after the switching valves SV3, SV4 in the second brake circuit BK2 have opened. If the leakage flow in the feed switching valve FV is small and one of the wheel brakes RB1, RB2, RB3, RB4 is blocked during emergency braking, ABS control can take place via the central outlet switching valve ZAV and the pressure supply unit DV.
  • a pressure sensor for example DG
  • a further pressure sensor for example DG2 in one of the brake circuits BK1, BK2 can be used, if available.
  • the pressure in the brake circuits BK1, BK2 can also be regulated via the electrical current in the motor of the pressure supply device DV according to predetermined current-pressure relationships (e.g. maps) stored in the ECU , whereby these current-pressure relationships can include dependencies of various boundary conditions, e.g. pressure build-up P up or pressure drop P down, solenoid valve positions, temperature, etc.
  • the brake fluid in the master cylinder can leak, which can uncontrollably influence the pedal travel (here: increase) and too much brake pressure and brake-by-wire so that it can cause undesirable hard braking.
  • the master cylinder be a single master cylinder, whereby the use of a tandem master cylinder is also possible.
  • the individual master cylinder can be connected to the storage container VB, as for example in FIG.
  • the leakage flow is blocked by the check valve RV1 and throttled by the throttle Drl in such a way that only an insignificantly small piston or pedal movement results, which causes the "brake-by-wire" - Braking only marginally disturbs.
  • the throttle Drl can be designed, for example, so that the pedal movement caused by the leak is approx. 0.2 mm / s. With an average braking time of approx. 3s to decelerate a vehicle at 100km / h with 1g, the pedal travel can be detuned by 0.6mm, which is small and negligible compared to the entire pedal stroke.
  • throttle Drl The combination of throttle Drl and check valve RV1 can therefore be seen as redundancy for sealing the pressure chamber via the primary seal D2.
  • the check valve RV1 enables a quick filling of the brake system with brake fluid as well as a quick venting via opened venting screws on the wheel cylinders RZ1, RZ2, RZ3, RZ4.
  • the throttle Drl also enables volume compensation in the event of temperature changes.
  • a critical double fault consisting of a leaky primary seal D2 and the additional sleeping single fault of a leaky secondary seal Dl, in which the leakage can no longer be throttled by the throttle Drl, can be caused by additional (not shown) redundant primary and / or secondary di be intercepted.
  • the tightness of the secondary seal Dl can be monitored regularly (for example at every parking stop) by means of a diagnosis.
  • the leak can be clearly assigned to the secondary seal D1.
  • the method in one of these cases can be implemented as follows, for example: Is achieved by appropriate valve switching after the vehicle has been parked and in particular when the brake pedal is actuated (i.e. when the brake pedal 1 is released) the residual pressure in the brake system via the open feed switching valve FV into the individual master cylinder, whereby the master cylinder piston 3 is moved into its starting position, in which brake fluid can be exchanged between the master cylinder and the reservoir VB (e.g. for Filling or sniffing), the tightness of the entire brake system can be checked during a time of 10s, for example, using the pressure change detected by the pressure sensor DG, with a pressure drop detected being able to indicate a tightness.
  • the individual master cylinder can be subjected to a constant pressure of 20 bar for a certain time via the pressure supply device DV.
  • the delivery rate can be determined, for example, via the change in angle in the motor of the pressure supply device DV detected by the rotor position sensor. If this is greater than the known delivery rate of the throttle Drl at 20 bar, for example, then the secondary seal Dl can be assessed as leaky. A double fault with a leaky primary D2 and secondary seal Dl can therefore only occur in the unlikely event that both seals Dl, D2 fail at the same time while driving.
  • a detected leak may not, under certain circumstances, be clearly assigned to the secondary seal Dl of the individual master cylinder, since the leak can also be due to a leaky path simulator seal D3 of the path simulator WS, which is caused by the Throttling through the leaky travel simulator seal D3 and via a further throttle Dr3 in at least one recess B7r in a travel simulator piston WSK, which connects a travel simulator empty space WSL via at least one opening cross-section in the outer surface of the travel simulator piston WSK with the travel simulator housing WSG in such a way that regardless of the position of the travel simulator piston WSK, the at least one opening cross-section or the opening cross-sections are located between the travel simulator seal D3 and a further redundant seal D3r in the travel simulator housing WSG, likewise to a small extent, the braking effect and can only lead to an insignificant influencing leakage flow.
  • the diagnosis for the tightness of the primary seal D2 can be carried out during braking by the force travel sensor KWS and the pedal travel sensors (Spl, Sp2).
  • the diagnosis can be made via the pressure sensor in the individual master cylinder and the pedal travel sensors (Spl, Sp2).
  • the storage container VB can have two mutually redundant fluid chambers.
  • the reservoir VB has a float 8 with a sensor target 7 in at least one fluid chamber, which, together with a level sensor element 6 on the PCB 5 of the electronic control unit ECU adjacent to the reservoir VB, can measure the level of the brake fluid in the reservoir VB almost continuously.
  • small leaks can also be detected redundantly in the brake circuit, for example leaks from Dl or from one of the wheel cylinders RZ1-RZ4.
  • the integration of the filling level sensor element 6 in the electronic control unit ECU can reduce costs.
  • FIG. 1b shows a further embodiment of a brake system which, compared to FIG.
  • the further bypass switching valve BP2 can be used in the second brake circuit BK2 in such a way that the second brake circuit BK2 with the wheel cylinders RZ3 and RZ4 can be decoupled from the rest of the brake system in the event of a fault in the second brake circuit BK2. As shown in Fig.
  • the second bypass switching valve BP2 can be used in the hydraulic line between the first bypass switching valve BPI and the pressure sensor DG in the second brake circuit BK2, the central outlet switching valve ZAV then via the second bypass switching valve BP2 can be connected to the second brake circuit BK2.
  • the combination of the two bypass switching valves BPI, BP2 can be used as Safety gate (SIG) may also be designated in a possible extension by the separation valve TV.
  • SIG Safety gate
  • the isolating valve TV can be used in the first brake circuit BK1 in such a way that the first brake circuit BK1 with the wheel cylinders RZ 1 and RZ2 can be decoupled from the rest of the brake system in the event of a fault (e.g. double faults RZ and SV) in the first brake circuit BK1.
  • a fault e.g. double faults RZ and SV
  • the isolating valve TV can be used in the hydraulic line between the pressure supply device DV or, if present, the check valve RV3 or a solenoid valve on the pressure supply device DV and the switching valves SV1, SV2 of the first brake circuit BK1.
  • a redundant pressure sensor DG2, not shown, can be coupled to the first brake circuit BK1.
  • the further central outlet switching valve ZAV2 can be used in the brake system in such a way that pressure in the brake system can be reduced redundantly to the central outlet switching valve ZAV.
  • it can for example be connected to the hydraulic line between the separating valve TV and the pressure supply device DV or, if present, the check valve RV3 or a solenoid valve on the pressure supply device DV.
  • the ZAV and ZAV2 should be connected to separate parts of the storage container VB.
  • ZAV2 can also be connected to the storage container VB via a further opening in the main cylinder and an annular sniffer opening in the piston 3.
  • the second bypass switching valve BP2 and the isolating valve TV can be designed as normally open solenoid valves, while the further central outlet switching valve ZAV2 can be designed as normally closed solenoid valve.
  • the output side of the second bypass switching valve BP2 and the isolating valve TV can also be connected to the second brake circuit BK2 or to the first brake circuit BK1 in such a way that, in the event of a valve control failure (e.g. when there is no current), the residual pressure causes them to flow into the Brake circuits BK1, BK2 can be opened.
  • the further central outlet switching valve ZAV2 also has the advantage that the pressure reduction P ab can be regulated independently during a vehicle dynamics intervention (e.g. ABS) in two wheel cylinders (RZ1, RZ2 or RZ3, RZ4) per brake circuit BK1, BK2.
  • a vehicle dynamics intervention e.g. ABS
  • RZ1, RZ2 or RZ3, RZ4 per brake circuit BK1, BK2.
  • the second bypass switching valve BP2 can increase safety if the feed switching valve FV can no longer be closed (for example due to a dirt particle or a fault in the electrical connection).
  • the individual master cylinder can be decoupled from the brake system and sufficient brake pressure can still be built up in the first brake circuit BK1 via the pressure supply device DV.
  • the pressure reduction P ab can take place, for example, via the further (central) outlet switching valve ZAV2.
  • the braking force can also be increased further after the opening of the second bypass switching valve BP2 by pressing the brake pedal 1 in the second brake circuit BK2. In this way, for example, a braking effect of approx.
  • the individual master cylinder can have further redundant primary and / or secondary seals, in particular a redundant primary seal D2r shown in FIG. 1b, which represents the redundancy for the pressure chamber seal.
  • the sniffer opening in the individual master cylinder between the primary seal D2 and the secondary seal Dl can be connected to the storage container VB via a so-called diagnostic valve VD, which is shown in FIG. 2 and described further below.
  • VD diagnostic valve
  • the pressure reduction P ab in the brake circuits BK1, BK2 cannot take place via the (central) outlet switching valves (ZAV and, if present, ZAV2) pressure can be reduced via the open feed switching valve FV and the individual master cylinder in the reservoir VB .
  • the pressure reduction P ab can take place in such a way that the limit volume flow of the diagnostic valve VD is not exceeded and the diagnostic valve VD thus remains open during depressurization.
  • the diagnosis described in Fig. 1a for monitoring the sealing of the master cylinder ie the tightness of the secondary di rect Dl, can be carried out in a similar manner via the diagnostic valve VD, the pressure supply device DV deliberately promoting volume flows above the closing volume flow from VD into the master cylinder because when the diagnostic valve VD is closed, the tightness can be determined via a pressure curve detected by the pressure sensor DG.
  • the hydraulic connection between the individual master cylinder and the storage container VB can also be replaced by the connection with the diagnostic valve VD from FIG.
  • a redundant primary seal D2r can be used to protect the primary seal D2 in the main cylinder, which, in contrast to FIG. 1 a, is not protected by a throttle / check valve combination (Drl, RV1).
  • the diagnosis for the tightness of the primary seal D2 (and the travel simulator seal D3) can be carried out during braking by the force travel sensor KWS and the pedal travel sensors (Spl, Sp2). Alternatively, the diagnosis can be made via the pressure sensor in the individual master cylinder and the pedal travel sensors (Spl, Sp2).
  • FIG. 2 shows a possible embodiment for a back pressure valve which can be used as a diagnostic valve VD ZB in FIG.
  • the back pressure valve can have two openings, wherein one of the two openings can have a valve seat and preferably an opening cross section that is larger than the other opening. Furthermore, it can have a plunger with sealing ball 18, the plunger being clamped in the valve housing by a spring F in the case of no fluid flow in such a way that the sealing ball 18 cannot close the valve seat of the preferably larger opening. If, on the other hand, a liquid flows through the opening with a valve seat via the opening without a valve seat, the predetermined geometry of the openings, valve seat and sealing ball 18 above a so-called closing volume flow can cause a dynamic pressure which presses the sealing ball 18 into the valve seat and thus the valve in this direction closes.
  • the diagnostic valve VD closes at volume flows above the closing volume flow, it can open again in the same flow direction if it falls below a further opening volume flow predetermined by the design of VD. In the other direction of flow, brake fluid can be conveyed through the valve without closing.
  • 3a-c, 3e show different embodiments according to the invention for a so-called fail-safe single master cylinder unit SHZ in a brake system according to the invention, wherein the safeguards described below can also be used in a tandem master cylinder unit THZ.
  • the respective individual master cylinder units SHZ described in connection with FIGS. 3a-c, 3e can be used in the brake systems according to FIGS. La-b, FIGS. 4a-c and 5a-b.
  • FIG. 3a shows an embodiment of a single master cylinder unit SHZ which, compared to that in FIG.
  • the master cylinder also has a further opening between the secondary seal Dl and the redundant secondary seal Dir, which is connected to the storage container VB via a throttle Dr4. By virtue of this connection, the tightness of the secondary seal Dl can also be diagnosed.
  • FIG. 3b shows an embodiment of a single master cylinder unit SHZ which, with regard to the connection of the master cylinder to the storage container VB, corresponds to that in FIG.
  • FIG. 3c shows an embodiment of a single master cylinder unit SHZ which has a redundant primary seal D2r and optionally a redundant secondary seal Dir.
  • the master cylinder can have a further opening between the primary seal D2 and the redundant primary seal D2r, both openings being connected via a hydraulic line, which in turn is connected to the via a switchable reservoir shut-off valve 17 Reservoir VB is connected.
  • the storage container shut-off valve 17 can be viewed as a redundancy for the pressure chamber seal, since it can be closed when one of the primary seals (D2, D2r) is leakproof.
  • the storage container shut-off valve 17 in FIG. 3c can be designed as a normally open solenoid valve. This means that the brake system can easily be filled and vented even when the power is off.
  • FIG. 3e shows a further embodiment according to the invention of a single master cylinder unit SHZ, the master cylinder housing 4 having at least one recess B1, also called a sniffer opening or opening, and optionally the master cylinder piston 3 having recesses B4, which are arranged and designed in this way are that the at least one pressure chamber 4a of the master cylinder, also called the master cylinder pressure chamber, is connected to the reservoir VB via a hydraulic line HL1 in a starting position of the brake pedal 1 predetermined by the piston stop KA, in particular when the brake pedal 1 is not actuated.
  • the master cylinder housing 4 having at least one recess B1, also called a sniffer opening or opening
  • the master cylinder piston 3 having recesses B4 which are arranged and designed in this way are that the at least one pressure chamber 4a of the master cylinder, also called the master cylinder pressure chamber, is connected to the reservoir VB via a hydraulic line HL1 in a starting position of the brake pedal 1 predetermined by the piston stop KA, in
  • the hydraulic line HL1 can contain a parallel connection of a throttle Drla and a check valve RV1 closing towards the storage container VB.
  • the brake system can be filled and vented through the hydraulic line HL1, sniffer opening B1 and recesses B4 in the master cylinder piston.
  • the main cylinder housing 4 has at least one primary seal D2 and at least one secondary seal D1, the at least one recess B1 lying between the primary seal D2 and the secondary seal D1. Furthermore, the master cylinder housing 4 has at least one redundant primary seal D2r, the master cylinder housing 4 having a further recess B2 between the primary seal D2 and the at least one redundant primary seal D2r, which is connected to the storage container VB via a hydraulic line HL2 and a further throttle Drl .
  • the hydraulic lines HL1 and HL2 can be connected via a common line piece, as shown in FIG. 3e, or separately, preferably to a chamber of the storage container VB.
  • the sealing of the master cylinder pressure chamber 4a in the master cylinder can be realized via a primary seal D2 and a secondary seal Dl as well as a further redundant primary seal D2r, in particular the redundant primary seal D2r from a certain brake pedal travel from which the recesses B4 in the master cylinder piston 3 the recess B2 between the primary seal D2 and the redundant primary seal D2r as well as the redundant primary seal D2r has passed, which represents the pressure chamber seal of the master cylinder.
  • the further throttle Drl in the hydraulic line HL2 can be viewed as redundancy for the pressure chamber sealing of the master cylinder by the redundant primary seal D2r, since if the primary seal D2r leaks and the primary seal D2 is intact, the brake fluid flow from the master cylinder pressure chamber 4a through the hydraulic line HL2 to the reservoir VB in this way that reduces the braking effect only insignificantly is affected.
  • the further throttle Drl can have a hydraulic resistance which, in the case of a leaky redundant primary seal D2r and a tight primary seal D2, is on the one hand so large that a pedal force-travel characteristic is not more than 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5 mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm and on the other hand is so small that the leakage can be diagnosed through the further throttle Drl.
  • a hydraulic output of the master cylinder can be connected to a travel simulator WS.
  • the master cylinder housing 4 can have a further recess B3 on the output side (i.e. when the brake pedal 1 is fully depressed), which is connected to the travel simulator WS via a hydraulic line HL3.
  • the hydraulic line between the feed switching valve FV and the main cylinder housing 4 can also be connected to the path simulator WS. As shown in Fig.
  • this hydraulic connection of the master cylinder to the path simulator can include a parallel connection of a throttle Dr2 and a non-return valve RV2 closing towards the path simulator WS, the two parallel hydraulic paths of this parallel connection each via a recess B5, B6 in the path simulator housing WSG can be connected to a path simulator pressure chamber WSD.
  • the two parallel hydraulic paths can be connected to the path simulator pressure chamber WSD via a common line piece and a recess, e.g. B5, in the path simulator housing WSG.
  • the travel simulator WS can transmit a certain pedal travel force characteristic to the brake pedal 1 via a travel simulator piston WSK, which can be disengaged against an arrangement of return springs 9 by pressing the foot on the brake pedal 1, for example.
  • the brake fluid volume flows from the master cylinder pressure chamber 4a, for example, through the hydraulic output B3, through the hydraulic line HL3 with throttle Dr2 and through the recess B5 of the path simulator WS into the path simulator pressure chamber WSD.
  • the brake pedal movement can be delayed via the throttle Dr2 and when the brake pedal 1 is released, the throttle Dr2 can be bypassed via the non-return valve RV2 for rapid emptying of the travel simulator WS.
  • the Driver Via the path simulator WS and the return spring RF in the main cylinder, the Driver a certain pedal travel force characteristic, which can preferably always be the same as possible and independent of the brake pressures in the brake circuits BK1, BK2.
  • the combination of travel simulator WS and return spring RF in the “brake-by-wire” system counteracts a failure of the brake pedal 1, e.g.
  • a brake circuit (BK1 or BK2) fails, and brings the brake pedal 1 back to a defined position after the foot is pressed Starting position back, the brake fluid volume flowing from the travel simulator pressure chamber WSD back into the master cylinder pressure chamber 4a. If the master cylinder piston 3 of the individual master cylinder unit SHZ returns to the defined starting position after the foot has been pressed on the brake pedal 1, brake fluid can also be exchanged between the master cylinder pressure chamber 4a of the master cylinder and the reservoir VB through recesses B4 in the master cylinder piston 3 and recess Bl in the master cylinder and via a hydraulic line HL1 (e.g. for thermal compensation).
  • the travel simulator WS has a travel simulator piston WSK which, as in FIG. 3e, is moved against a spring assembly when brake fluid is pushed into the travel simulator pressure chamber WSD via the master cylinder.
  • the path simulator piston WSK can have at least one recess or recesses B7 which connect the path simulator pressure chamber WSD to the path simulator housing WSG via at least one opening cross-section in the outer surface of the path simulator piston WSK, i.e. brake fluid from the path simulator pressure chamber WSD can reach the inner surface via the at least one recess or recess B7 of the path simulator housing WSG.
  • the path simulator piston WSK can have at least one redundant recess or redundant recesses B7r, which also connects the path simulator pressure chamber WSD to the path simulator housing WSG via at least one further opening cross-section in the outer surface of the path simulator piston WSK, ie brake fluid in the vicinity of the at least one further opening cross-section between the path simulator housing WSG and the path simulator piston WSK can flow into the path simulator empty space WSL via the at least one redundant cutout or the redundant cutouts B7r.
  • Each of the cutouts B7 and the redundant cutouts B7r represents a throttle in the following sense:
  • Each of the at least one cutout B7 in the travel simulator piston WSK can each contain a third throttle Dr3 and each of the at least one redundant recess B7r in the travel simulator piston WSK can contain a third redundant throttle Dr3r.
  • some or all of these third throttles Dr3 or third redundant throttles Dr3r can also be implemented by orifices.
  • the cutouts B7, B7r can also already have a corresponding throttle or diaphragm effect due to their geometry.
  • the number of cutouts B7 can be equal to or different from the number of redundant cutouts B7r.
  • the recesses B7 can be distributed over the angle of the cylindrical travel simulator piston WSK.
  • the redundant cutouts B7r can also be distributed over the angle of the cylindrical travel simulator piston WSK.
  • the opening cross-sections of the recesses B7 are preferably arranged at one and the same height of the travel simulator piston WSK (intended as a cylinder) and the further opening cross-sections of the redundant recesses B7r are also preferably arranged at another same height of the travel simulator piston WSK.
  • the overall throttling effect (also referred to as the third throttle Dr3) of these cutouts B7r is important, and in the case of several redundant cutouts B7r, the overall throttling effect (also referred to as the third redundant throttle Dr3r) of these redundant cutouts B7r is important at. It is therefore sufficient in the following to describe the case of a cutout B7 and a redundant cutout B7r.
  • the travel simulator housing WSG has at least one first travel simulator seal D3 (also called the primary seal of the travel simulator), which serves to seal the pressure chamber of the travel simulator pressure chamber WSD, in particular with the at least first travel simulator seal D3 in an unpressurized starting position (e.g. when the brake pedal 1 is not actuated) of the travel simulator piston seals against the path simulator empty space WSL.
  • the travel simulator housing WSG has at least one second travel simulator seal D3r (also called redundant primary seal of the travel simulator), which also serves to seal the travel simulator pressure chamber WSD, in particular with the at least one second travel simulator seal D3r starting from a certain position of the travel simulator piston WSK the travel simulator pressure chamber against the travel simulator pressure chamber WSL seals.
  • This certain position of the travel simulator piston WSK is reached when the other Opening cross-section of the redundant recess B7r in the lateral surface of the travel simulator piston WSK which has passed at least one second travel simulator seal or the second travel simulator seals D3r. Only the case of a first travel simulator seal D3 and a second travel simulator seal D3r is detailed below.
  • the at least one recess B7 and the at least one redundant recess B7r in the path simulator piston WSK are placed in such a way that, in no position of the path simulator piston WSK, the at least one opening cross-section in the outer surface of the path simulator piston WSK for the at least one recess B7 and the at least one further opening cross-section in the The outer surface of the travel simulator piston WSK for the at least one redundant recess B7r is located between the at least first travel simulator seal D3 and the at least second travel simulator seal D3r.
  • the redundant recess B7r is located between the first travel simulator seal D3 and the second travel simulator seal D3r. If the path simulator pressure chamber WSD is filled with brake fluid, the path simulator piston WSK moves, in the normal case. If the path simulator piston WSK is moved far enough (ie from a certain position), the recess B7 of the path simulator piston WSK is between the first path simulator seal D3 and the second path simulator seal D3r, while the redundant recess B7r of the path simulator piston WSK is the space between the first path simulator seal D3 and the second travel simulator seal D3r has left.
  • the travel simulator pressure chamber WSD is sealed by the first travel simulator seal D3. If, with the displacement simulator piston WSK, the recess B7 is located between the first displacement simulator seal D3 and the second displacement simulator seal D3r, the displacement simulator pressure chamber WSD is sealed by the second displacement simulator seal D3r. In this With regard to this, the first travel simulator seal D3 and the second travel simulator seal D3r can be seen as a pressure chamber seal for the travel simulator pressure chamber WSD.
  • the placement of the first travel simulator seal D3 and the second travel simulator seal D3r in the travel simulator housing WSG is advantageously such that even with many braking operations in the lower vehicle deceleration range , e.g. from 0.5m / s 2 , 0.6m / s 2 , 0.7m / s 2 , 0.8m / s 2 , 0.9m / s 2 , 1.0m / s 2 , 1.1m / s 2 , 1.2m / s 2 , 1.3m / s 2 , 1.4m / s 2 or 1.5m / s 2 , the recess of the
  • Travel simulator piston B7 is already located between the first travel simulator seal D3 and the second travel simulator seal D3r.
  • a throttled leakage flow from the path simulator pressure chamber WSD via the at least one recess B7 and an annular gap in a rear area between the path simulator piston WSK and the path simulator housing WSG and via the at least one redundant recess B7r into the Path simulator empty space WSL takes place when the at least one redundant recess B7r is located between the at least one first path simulator seal D3 and the at least one second path simulator seal D3r, the rear area meaning an area facing the path simulator pressure chamber WSD.
  • the leakage flow can be throttled here in particular by a parallel connection of the hydraulic resistance of the at least one recess B7 and the hydraulic resistance of the annular gap in the rear area of the travel simulator piston WSK.
  • a throttled leakage flow from the travel simulator pressure chamber WSD via the at least one recess B7 and via the at least one redundant recess B7r and a further annular gap in a front area between the travel simulator piston WSK and the travel simulator housing WSG take place in the path simulator empty space WSL if the at least one recess B7 is located between the at least one first path simulator seal D3 and the at least one second path simulator seal D3r, with the front area being one of the Path simulator empty space WSL facing area is meant.
  • the leakage flow can be throttled here in particular by a parallel connection of the hydraulic resistance of the at least one redundant recess B7r and the hydraulic resistance of the annular gap in the front area of the travel simulator piston WSK.
  • the leakage caused by a leaky first path simulator seal D3 (with a tight second path simulator seal D3r) or by a leaky second path simulator seal D3r (with a tight first path simulator seal D3) from the path simulator pressure chamber WSD into the path simulator empty space WSL can be throttled in such a way that, on the one hand, a Characteristic shifts by no more than 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm and on the other hand the leakage can be diagnosed.
  • the third throttle Dr3 and the third redundant throttle Dr3r have different hydraulic resistances.
  • the advantage can then consist in the fact that a leak can be assigned to either the first travel simulator seal D3 or the second travel simulator seal D3r on the basis of leakage flows of different sizes.
  • the physical reason is that without the parallel connection of hydraulic resistors, only the series connection of the hydraulic resistance of the third throttle and the hydraulic resistance of the third redundant throttle Dr3r would be important. In this case, the leakage path would always be the same regardless of the position of the travel simulator piston WSK, and a leak could not be clearly assigned to the first travel simulator seal D3 or the second travel simulator seal D3r.
  • a plurality of cutouts B7 and / or a plurality of redundant cutouts B7r with a respective throttling effect can prove to be advantageous in that individual cutouts B7, B7r can become blocked.
  • Such several (redundant) recesses B7, B7r can thus be seen as redundancy for the redundancy of the travel simulator pressure chamber seal and are particularly beneficial to safety.
  • the pedal travel sensors Spl, Sp2 can be implemented in different ways. InFig. 3e, the pedal travel sensors Spl, Sp2 are coupled to the intermediate tappet 2a, the master cylinder piston 3 and a spring FKWS between the master cylinder piston 3 and the intermediate tappet 2a.
  • the brake pedal 1 of the hydraulic brake pedal system can act on the master cylinder piston 3 in the master cylinder via the intermediate tappet 2a and the spring FKWS.
  • the FKWS spring can be pretensioned.
  • the master cylinder can have at least one displacement sensor Spl for detecting the engagement path of the master cylinder piston 3 and at least one further displacement sensor Sp2 for detecting the engagement path of the intermediate tappet 2a.
  • the intermediate tappet 2a exerts a force on the spring FKWS. If this force is greater than the preload of the spring FKWS, then there is a shift between the intermediate tappet 2a and the master cylinder piston 3. This shift can be calculated using the pedal travel sensors (Spl and Sp2). If the characteristics of the spring FKWS are known, the spring force can be determined from the displacement between the intermediate tappet 2a and the master cylinder piston 3. Given known friction conditions between the intermediate tappet 2a and the master cylinder piston 3, the force which the pedal tappet 2 exerts on the intermediate tappet 2a can then be calculated.
  • the force with which the driver operates the brake pedal 1 can be calculated from the force which the pedal tappet 2 exerts on the intermediate tappet 2a.
  • the displacement of the brake pedal 1 or the driver's foot can be determined with the pedal travel sensor Sp2.
  • the pedal characteristic that is to say the force-path characteristic of the brake pedal 1
  • a pedal force can be calculated from the difference in the engagement paths of the master cylinder piston 3 and the intermediate tappet 2a as well as a force-displacement characteristic of the spring FKWS between the master cylinder piston 3 and the intermediate tappet 2a.
  • the pedal travel sensor Spl can be supplemented by a redundant pedal travel sensor Spl.l for the purpose of redundant detection of the engagement travel of the master cylinder piston 3.
  • the pedal travel sensor Sp2 can also be supplemented by a redundant pedal travel sensor Sp2.1 for the purpose of redundant detection of the engagement travel of the intermediate tappet 2a.
  • the calculated pedal characteristic corresponds to a defined pedal characteristic. If the calculated pedal characteristic deviates from the defined pedal characteristic, then, taking tolerances into account, there is an error.
  • Double faults such as a leak in both main cylinder seals (D2 and D2r), can still be detected.
  • a double fault is understood here to mean that two component faults that are not subject to the same fault origin occur at the same time.
  • the throttle Drla in the hydraulic line HL1 is provided in the event that, for example, both master cylinder seals (D2 and D2r) are leaking.
  • the feed switching valve FV is opened in this case, whereby brake fluid from the pressure supply device DV (not shown, see e.g. Fig. La) through the feed switching valve FV into the pressure chamber 4a of the master cylinder and through the leaky master cylinder seals (D2 and D2r ), about the Ausspamng Bl and flows into the reservoir VB via the hydraulic line HL1 with throttle Drla.
  • This creates a dynamic pressure via the throttle Drla which increases the pressure in the master cylinder pressure chamber 4a and thus the brake pedal force.
  • the pressure in the master cylinder pressure chamber 4a and thus the force level of the brake pedal 1 can be raised to the normal level via the control of the pressure supply device (DV, not shown, see Fig.
  • a non-return valve RV1 closing towards the reservoir VB is provided, which enables rapid filling of the brake system with brake fluid and rapid venting via open venting screws on the wheel cylinders RZ1, RZ2, RZ3, RZ4.
  • the throttle Drla also enables volume compensation in the event of temperature changes. Compared to the further throttle Drl, the throttle Drla can have a lower hydraulic resistance.
  • the brake system can have various sensors, redundant pedal travel sensors Spl.l, Sp2.1 for determining the pedal travel, a force travel sensor (KWS, see description Fig. La) in the piston 3 of the master cylinder for determining a force-pedal travel characteristic, a level sensor element 6 to determine the level of the
  • a pressure sensor (not shown) can be integrated in the master cylinder, which can detect the pressure in the master cylinder pressure chamber 4a and transmit it to the ECU.
  • a critical fault consisting of a leaky primary seal D2 can be intercepted by a further redundant primary seal D2r.
  • the sealing of the master cylinder pressure chamber 4a takes place by the redundant primary seal D2r of the master cylinder.
  • the leak in the primary seal D2 can be detected.
  • the method can be implemented as follows, for example: In the event of a leak in the redundant primary seal D2r of the master cylinder pressure chamber 4a, the loss of brake fluid volume from the master cylinder pressure chamber 4a is transferred to the reservoir VB the hydraulic lines HL1, HL2, delayed by a throttle Drl in the hydraulic line HL2.
  • the leakage current from the throttle Drl is throttled in such a way that only an insignificantly small piston or pedal movement results, which only insignificantly disrupts the “brake-by-wire” braking.
  • the throttle Drl can, for example, be designed so that the pedal movement caused by the leakage is approx. 0.2mm / s.
  • an average braking time of approx. 3s to decelerate a vehicle at 100km / h with 1g the pedal travel can be detuned by 0.6mm, which is small and negligible compared to the entire pedal stroke.
  • the HL1 hydraulic line enables the brake system to be quickly filled with brake fluid and vented, and also enables volume compensation in the event of temperature changes.
  • the leakage current just described due to a leaky redundant primary seal D2r can be detected in the following way. If the master cylinder pressure chamber 4a is closed by the redundant primary seal D2r, then an increase in the travel of the master cylinder piston 3 also includes a defined increase in the signal from the force-travel sensor KWS. If the redundant primary seal D2r of the master cylinder is leaking, then the increase in the signal from the force-displacement sensor KWS is smaller than the defined increase in the force-displacement sensor signal. Conversely, if the increase in the signal from the force-displacement sensor KWS is smaller than the defined increase in the force-displacement sensor signal, then this indicates a leak in the redundant primary seal D2r of the master cylinder.
  • the primary seal D2 of the master cylinder fails, ie if the primary seal D2 leaks, the brake fluid may leak in the master cylinder pressure chamber 4a, which uncontrollably influences the pedal travel (here: increase) and, via "brake-by-wire", too much brake pressure and thus undesirable cause hard braking. If this is greater than the known delivery rate of the throttle Drl at the existing pressure in the master cylinder pressure chamber 4a, e.g. 20 bar, then the primary seal D2 can be assessed as leaky.
  • the redundant recess B7r of the path simulator piston WSK is located between the first path simulator seal D3 and the second path simulator seal D3r, and if the second path simulator seal D3r is intact, the first path simulator seal D3 is leaking, then a leakage flow of brake fluid flows from the path simulator pressure chamber WSD through the third redundant throttle Dr3r into the path simulator empty space WSL.
  • the redundant third throttle Dr3r can be dimensioned so small that the leakage current is so low that the pedal movement caused by the leakage is approx. 0.2mm / s. With an average braking time of approx.
  • the pedal travel can be detuned by 0.6mm, which is small and negligible compared to the entire pedal stroke. If the path simulator piston WSK is in the same position and the first path simulator seal D3 is intact, the second path simulator seal D3r leaks, then the seal of the path simulator pressure chamber WSD remains intact.
  • the leakage current just described due to a leaky first displacement simulator seal D3 can be recognized in the following way. If the path simulator pressure chamber WSD is normally closed by the first path simulator seal D3, then an increase in the path of the master cylinder piston 3 also includes a defined increase in the signal from the force-path sensor KWS, with a possible leakage current from the master cylinder pressure chamber 4a through the hydraulic line HL2 with throttle Drl and hydraulic line HL1 to the reservoir VB must be taken into account. If the first displacement simulator seal D3 of the displacement simulator WS is leaking, then the increase in the signal from the force-displacement sensor KWS is smaller than the defined increase in the force-displacement sensor signal. Conversely, if the increase in the signal from the force-displacement sensor KWS is smaller than the defined increase in the force-displacement sensor signal, then this indicates a leak in the first displacement simulator seal D3 of the displacement simulator WS.
  • the third throttle Dr3 can be dimensioned so small that the leakage current is so small that the pedal movement caused by the leakage is approx. 0.2mm / s. With an average braking time of approx. 3s to decelerate a vehicle at 100km / h with 1g, the pedal travel can be detuned by 0.6mm, which is small and negligible compared to the entire pedal stroke. If WSK is in the same position of the travel simulator piston, and if the second one is intact Travel simulator seal D3r, the first travel simulator seal D3 leaking, then the seal of the travel simulator pressure chamber WSD remains intact.
  • the leakage current just described due to a leaky second travel simulator seal D3r can be recognized in the following way. If the path simulator pressure chamber WSD is normally closed by the second path simulator seal D3r, then an increase in the path of the master cylinder piston 3 also includes a defined increase in the signal from the force-path sensor KWS, with a possible leakage flow from the master cylinder pressure chamber 4a through the hydraulic line HL2 with throttle Drl and hydraulic line HL1 to the reservoir VB must be taken into account. If the second displacement simulator seal D3r is leaky, the increase in the signal from the force-displacement sensor KWS is smaller than the defined increase in the force-displacement sensor signal. Conversely, if the increase in the signal from the force-displacement sensor KWS is smaller than the defined increase in the force-displacement sensor signal, then this indicates a leak in the second displacement simulator seal D3r of the displacement simulator WS.
  • a detected leak in the redundant primary seal D2r of the master cylinder analogous to the diagnosis just described cannot, under certain circumstances, be clearly assigned to the redundant primary seal D2r of the master cylinder, since the leak can also be due to a leaky first travel simulator seal D3 or a leaky second travel simulator seal D3r.
  • different designs of the hydraulic resistances for the different throttles (Drl, Dr3 and Dr3r) can lead to different leakage flows through the different throttles (Drl or Dr3 and Dr3r) can be set, whereby the diagnosis just described can then localize the leakage in the seals (D2r, D3 or D3r) of the master cylinder pressure chamber 4a more precisely.
  • the hydraulic resistance of the throttle Drl acting as redundancy for the pressure chamber seal in the connection to the master cylinder on the reservoir VB and the hydraulic resistances of the third (redundant) throttles Dr3, Dr3r of the cutouts or redundant cutouts of the path simulator WS can be designed in such a way that a leak can be assigned either to the pressure chamber seal (D2, D2r) of the master cylinder or to the travel simulator seal (D3, D3r).
  • the hydraulic resistance of the throttle Drl acting as redundancy for the pressure chamber sealing in the connection to the master cylinder on the reservoir VB, the hydraulic resistance of the throttle Dr3 of the at least one recess and the hydraulic resistance of the further throttle Dr3r of the at least one redundant recess of the path simulator WS can be be designed so that a leak in the pressure chamber seal (D2, D2r) of the master cylinder, the first travel simulator seal D3 or the second travel simulator seal D3r can be assigned.
  • the vehicle deceleration can optionally also be taken into account here.
  • the hydraulic connection of the opening of the main cylinder between the at least one primary seal D2 and the at least one secondary seal Dl to the reservoir VB consists here of only one line, which in particular does not contain any valves or throttles.
  • the main cylinder also has at least one primary seal D2r redundant to the primary seal D2, the main cylinder having at least one further opening between the at least one redundant primary seal D2r and the at least one primary seal D2, which is connected to the storage container VB via a throttle.
  • the redundant primary seal D2r represents the pressure chamber seal of the at least one pressure chamber of the master cylinder.
  • the throttle can have a hydraulic resistance which, if the redundant primary seal D2r and the tight primary seal D2 are leaking, is so great that a pedal force-travel characteristic is established by no more than 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm, and on the other hand is so small that the leakage through the throttle can be diagnosed.
  • the throttle can thus be seen as a redundancy of the pressure chamber seal of the at least one pressure chamber of the master cylinder.
  • the secondary di rectification Dl represents Sealing of the main cylinder to the outside. If the secondary seal Dl leaks, the main cylinder and / or the storage container VB can empty to the outside. The risk of such emptying exists especially when the vehicle is stationary for a long period of time. When the vehicle is started, however, the fill level in the storage container VB can be queried via the fill level sensor element 6 and a sufficient fill level can be ensured. Any leakage can thus be diagnosed.
  • a redundant secondary seal can also be used as redundancy to seal off the master cylinder from the outside.
  • a lack of safety in general means here that an individual failure of an element of the brake system is protected by redundancy and the failure of the element of the brake system or the failure of the redundancy can be determined by means of a diagnosis.
  • a single failure is a failure (or failure) of only one element of the braking system.
  • Double failures or double failures or multiple failures (or multiple failures), on the other hand, denote failures (or errors) of two or more elements of the braking system.
  • double or multiple errors can be accepted if their occurrence is very unlikely.
  • double faults which can lead to total failure of the braking system, should be avoided in a fail-safe system.
  • Double errors in a fail-safe system can be avoided if so-called dormant single errors, which lead to double errors with a further single error, are secured or recognized by redundancy with additional diagnosis.
  • a fail-safe single master cylinder requires that the pressure chamber seal of the master cylinder is fail-safe.
  • the pressure chamber of an individual master cylinder is sealed, for example, by the primary seal D2 of the individual master cylinder.
  • An individual failure of the seal of the individual master cylinder pressure chamber for example caused by a leaky primary seal D2, can lead to a total failure of the brake system.
  • the desired safety failure therefore requires at least one redundancy for the pressure chamber seal and at least one diagnosis of the pressure chamber seal or the redundancy of the pressure chamber seal.
  • a fail-safe master cylinder can be used in stages three to four in accordance with the SAE J3016 standard. The required at least one redundancy for the pressure chamber sealing can, for example
  • redundancies can be combined in a meaningful way to increase the safety.
  • a redundancy (combination Drl / RVl or storage tank shut-off valve 17) in the connection of the master cylinder to the storage tank VB, further redundant primary seals (e.g. D2r) can be used.
  • D2r further redundant primary seals
  • a combination of the combination Drl / RVl and reservoir shut-off valve 17 is also conceivable.
  • the at least one diagnosis of the pressure chamber seal or the redundancy of the pressure chamber seal can be implemented as a diagnosis of the pressure chamber seal, e.g.
  • the throttle / check valve combination (Dr3, RV1) can be diagnosed as described above via the residual pressure in the brake system or via the pressure supply device DV when the vehicle is stationary, preferably when parking, by the return to the reservoir VB, which can be determined, for example, from the delivery volume of the pressure supply device DV and / or from the change in level in the reservoir VB, is compared with the expected blocking by the check valve RV1 and the throttling by the throttle Drl; or as in Fig. 3c, the tightness of the switchable storage tank shut-off valve 17, possibly including the level sensor in the Reservoir VB, can be checked.
  • the safety can be increased by diagnoses which are made during braking and thus in particular several times while driving.
  • Other redundant primary seals (e.g. D2r) in the master cylinder can also be diagnosed using the KWS force travel sensor or the pressure sensor in the pressure chamber of the master cylinder.
  • the path simulator WS should also be fail-safe.
  • a path simulator WS is fail-safe if the pressure chamber seal of the path simulator WS is fail-safe. In the regular case, that is to say in the absence of defects, the pressure chamber of the path simulator WS is sealed, for example, by the path simulator seal D3 of the path simulator WS.
  • a single failure of the seal of the travel simulator pressure chamber for example caused by a leaky travel simulator seal D3, can also lead to a total failure of the brake system.
  • the desired safety failure therefore requires at least one redundancy for the pressure chamber seal and at least one diagnosis of the pressure chamber seal or the redundancy of the pressure chamber seal.
  • the required at least one redundancy for the pressure chamber seal can be achieved, for example, by a second redundant travel simulator seal D3r; or as in Fig. la, Fig. 1b, Fig. 3a, Fig. 3b and Fig. 3c by a second redundant travel simulator seal D3r and the already described throttling of the leakage by the throttle Dr3 between the travel simulator D3 and the redundant travel simulator seal D3r, in this case with a slow pedal travel change; or as in Fig. 3e by a first travel simulator seal D3 and a second travel simulator seal D3r, as well as by a third throttle Dr3 and a redundant third throttle Dr3r, which together represent the redundancy by throttling the leakage.
  • the at least one diagnosis of the pressure chamber seal of the travel simulator or the redundancy of the pressure chamber seal can be implemented as a diagnosis of the pressure chamber seal, e.g.
  • the tightness of the travel simulator seal D3 with corresponding valve positions via the residual pressure in the brake system or via the pressure supply device DV when the vehicle is stationary, preferably when Parking, is monitored by the return to the storage container VB, which, for example, on the delivery volume of the
  • Pressure supply device DV and / or can be determined via the level change in the storage container VB is compared with the expected blocking by the check valve RV1 and the throttling by the throttles (Drl, Dr2), possibly including the level sensor in the storage container VB; or as in Fig. 3c, with the pressure supply device DV and corresponding valve positions (eg closed SV1, SV2, SV3, SV4, ZAV, 17 and open BPI, FV, 14) the tightness of the travel simulator seal D3, possibly including the level sensor in the storage container VB, can be checked.
  • the pressure supply device DV and corresponding valve positions eg closed SV1, SV2, SV3, SV4, ZAV, 17 and open BPI, FV, 14
  • diagnoses can be combined in a meaningful way.
  • a diagnosed leak in the coupled pressure chamber cannot generally be localized, as this can be caused, for example, by a leaky primary seal D2 of the master cylinder as well as by a leaky path simulator seal D3, D3r. This is sufficient for the failure of safety insofar as a diagnosed tightness in the coupled pressure chamber implies the tightness of both seals (D2, D3). If the path simulator isolating valve 14 is present, any leakage in the path simulator WS or the master cylinder can be localized.
  • An individual failure of the seal of the individual master cylinder to the outside e.g. a leaky secondary seal Dl, which can lead to a loss of brake fluid, can e.g. due to redundancy
  • the filling level sensor 6 in the storage container VB can also or additionally be used for leak detection.
  • the safety requirements for the sealing of the feed switching valve FV in the closed state i.e. the sealing of the feed switching valve FV, which in the regular case takes place, for example, by a seal in the valve seat, can also be weaker than for sealing the main cylinder pressure chamber, since the consequences of the faults are less critical.
  • security is guaranteed if at least one redundancy of the element and / or a failure of the element can be diagnosed.
  • a single failure of the seal of the feed switching valve FV which, for example, is caused by a dirt particle, impairs the “brake-by-wire” functionality and can detune the force-travel characteristics of the brake pedal system, can be caused, for example, by a redundancy - by another one connected in series (not shown in the figures)
  • Solenoid valve or as in Fig. La, Fig. 1b, Fig. 3a, Fig. 3b, Fig. 3c and already described by deactivating the second brake circuit BK2 by closing the solenoid valves ZAV, SV3, SV4, BPI or possibly ZAV, BPI , BP2, where there is still sufficient braking force via the first brake circuit BK1 (for example, depending on the wheel division, 50% braking effect) for
  • the tightness of the closed feed switching valve FV can be determined via the pressure supply device DV and changes in the pedal travel.
  • redundancies and diagnoses can be combined in various sensible ways.
  • FIG. 3d shows an exemplary pedal force-travel characteristic (21) of the brake pedal 1 of the individual master cylinder unit SHZ in FIG. 3c, the pedal travel Sp being indicated relative to the total pedal travel.
  • the restoring force of the brake pedal 1 is generated by a restoring spring RF1 in the master cylinder (range up to 10% in FIG.
  • a further return spring RF2 can be integrated in the master cylinder, which adjusts the gradient of the pedal force-travel characteristic of the brake pedal 1, e.g. from approx. 10% of the pedal travel increases.
  • a preferred embodiment of the brake system according to the invention can be derived from Fig. 3b, with the diagnostic valve VD in the connection of the master cylinder to the reservoir VB being dispensed with, ie the master cylinder is directly connected to the reservoir via the sniffing opening between the primary D2 and secondary seal Dl VB connected.
  • the single master cylinder in this embodiment is fail-safe thanks to the redundant primary seal D2r, the redundant travel simulator seal D3r and the force travel sensor KWS according to the definition above.
  • a leak in the secondary seal D1 can be diagnosed when the vehicle is stationary via the level sensor element 6 in the storage container VB or on the PCB.
  • the secondary seal Dl can be applied by applying compressed air to e.g. 5 bar in the storage tank
  • the travel simulator WS shown in Fig. 3e and / or the brake pedal system with the force travel sensor system with redundant pedal travel sensors Spl.l., Sp2.1 can also be used with other embodiments according to the invention, in particular those in Fig. La-b, Fig. 3a-c, Fig 4a-c, 5a-b, can be combined.
  • Fig. 4a shows a further embodiment of a brake system according to the invention, in comparison to Fig. La and Fig May have central rod, the piston via the central rod and a gear with an electromotive Drive can be moved in both directions.
  • the gearbox can be implemented as a ball screw drive and the electromotive drive can be implemented as a brushless DC motor or in some other way.
  • the respective designs of the pressure supply device DV described in connection with FIGS. 4a-c and 5a-b can be used in or with the systems according to the invention according to FIGS. La-b and FIGS. 3a-c.
  • connection of the wheel cylinders (e.g. RZ1, RZ2) to a brake circuit (e.g. BK1) can, as known in the prior art, take place via a switchable inlet valve (e.g. EVI, EV2), with the wheel cylinders (e.g. RZ1, RZ2) then via a switchable outlet switching valve (e.g. AVI, AV2) can be connected to the storage container VB.
  • the inlet valves or outlet switching valves can also be seen as switching valves.
  • the wheel cylinders (e.g. RZ3, RZ4) can be connected to a brake circuit (e.g. BK2) as in Fig. La and Fig central outlet switching valve ZAV and possible further valves can be switchably connected to the storage container VB.
  • a connection can reduce the number of solenoid valves, which can save costs.
  • One of the two pressure chambers of the double piston pump can be connected to the first brake circuit BK1 via a hydraulic output of the pump and via a check valve RV3 closing towards the pressure supply device DV and possible further valves. Furthermore, this pressure chamber can be connected to the storage container VB via a suction inlet (sniffer opening or opening) of the pump and a further non-return valve RV6 closing towards the storage container VB, as well as via possible further valves. The other pressure chamber can also be connected to the second brake circuit via a further hydraulic output of the pump and a non-return valve RV4 closing towards the pressure supply device DV, as well as possible further valves.
  • pressure chamber can also be connected to the storage container VB via a further suction inlet (sniffing opening or opening) of the pump and a further non-return valve RV5 closing towards the storage container VB, as well as possible further valves.
  • the pump with the two suction inlets and the two hydraulic outlets as well as the piston can be designed in such a way that in both directions of movement of the piston, ie both during Before and during the return stroke, brake fluid is pumped from the reservoir VB into at least one of the two brake circuits BK1, BK2 and thus brake pressure can be built up, whereby, by definition, the forward stroke denotes the direction of movement of the piston in which brake fluid is drawn from the pressure chamber facing away from the central rod of the piston (in Fig.
  • the return stroke denotes the direction of movement of the piston in which brake fluid is pushed out of the other pressure chamber (in Fig. 4a via RV4), whereby the piston effective area of the piston can be smaller compared to the piston effective area of the piston during the forward stroke.
  • the two brake circuits BK1, BK2 can be connected in a switchable manner as in FIG. La by a bypass switching valve BPI or as in FIG.
  • brake pressure can optionally be built up in the first brake circuit BK1 or in both brake circuits BK1, BK2.
  • Pressure supply device DV optionally brake pressure can be built up in the second brake circuit BK2 or in both brake circuits BK1, BK2.
  • the brake system according to the invention with a double stroke piston pump and an exemplary connection as in FIG. 4a can prove to be advantageous in this respect than the amount of time that can be saved, which then arises with a single-stroke piston pump when the piston is closed with the hydraulic outlet of the hydraulic outlet of the
  • braking pressure can be continuously provided in the brake circuits BK1, BK2 with the double-stroke piston pump in FIG. 4a by alternating forward and reverse strokes. In this way, in particular, the overall length of the double-piston pump can be reduced.
  • the brake system according to the invention with a double piston pump and an exemplary connection as in Fig. 4a can, on the other hand, prove to be advantageous insofar as the different sizes of effective piston areas during the forward and return strokes of the piston in the design of the transmission and the electric motor drive are used for so-called downsizing can.
  • a normal pressure range from pressures up to the so-called blocking pressure with a high coefficient of friction in the wheel / ground system of e.g. approx. 100-120 bar and on the other hand a higher pressure range from pressures up to e.g. approx. 200 bar -
  • the effective piston surfaces of the piston, the gearbox and the electric motor of the double-stroke piston pump can preferably be designed in such a way that pressures in the normal pressure range can still be adequately supported during the forward stroke, while pressures in the higher pressure range can only be supported by the smaller piston back.
  • Advance strokes with the larger rear side of the piston can prove to be particularly advantageous if, when filling the wheel cylinder, the brake clearance must first be overcome as quickly as possible, in which the brake pressure rises relatively slowly.
  • Return strokes with the smaller rear side of the piston can prove to be particularly advantageous when the pressure increases significantly after the clearance of the brakes has been overcome and less brake fluid volume has to be conveyed when the pressure rises sharply.
  • an empty pre-stroke when the pressure builds up P on, after a return stroke in the higher pressure range, an empty pre-stroke may be required, which means, for example, with closed switching valves (e.g. SV3, SV4) and inlet valves (e.g. EVI, EV2), a closed feed switching valve FV, if present, a preferably closed second bypass switching valve BP2, an opened first bypass switching valve BPI and an opened central outlet switching valve ZAV brake fluid can be conveyed from the pressure chamber with the larger piston effective area into the reservoir VB.
  • closed switching valves e.g. SV3, SV4
  • inlet valves e.g. EVI, EV2
  • FV closed feed switching valve
  • BP2 if present, a preferably closed second bypass switching valve BP2
  • an opened first bypass switching valve BPI and an opened central outlet switching valve ZAV brake fluid can be conveyed from the pressure chamber with the larger piston effective area into the reservoir VB.
  • Such an empty pre-stroke can take up to
  • a pressure reduction P ab such as an ABS intervention via outlet switching valves (e.g. AVI, AV2) per brake cylinder (e.g. RZ1, RZ2)
  • a pressure reduction P ab via the switching valves e.g.
  • SV3, SV4 and a central outlet switching valve ZAV, whereby the switching valves and / or the bypass switching valves BPI, BP2 can be controlled via pulse width modulation (PWM), are rated as advantageous with regard to the accuracy in pressure differences between the individual wheel cylinders RZ1, RZ2, RZ3, RZ4 and / or brake circuits BK1, BK2.
  • PWM pulse width modulation
  • the noise development can also be reduced to a certain minimum.
  • the piston of the double-stroke piston pump can be brought back to its starting position via its electric motor drive in the event of a complete pressure reduction P ab , with the brake fluid volume from the pressure chamber with the smaller piston effective area also via at least one of the bypass switching valves BPI, BP2 and the central outlet switching valve ZAV is promoted into the storage tank VB.
  • FIG. 4b shows a further embodiment in which, compared to FIG. 4a, the check valve RV3 at the pump outlet of the pressure chamber with the larger effective area is preferably replaced by a switchable solenoid valve PD1.
  • the brake circuits BK1, BK2 can be connected by a bypass switching valve BPI or by a series connection of two bypass switching valves BPI, BP2.
  • another switchable isolating valve TV can be used in the first brake circuit BK1.
  • the switchable solenoid valve PD1 With a forward stroke of the piston, the switchable solenoid valve PD1 can be opened and pressure can be built up in the brake circuits BK1, BK2, as in FIG. 4a. On the other hand, can be closed PD1 during a return stroke of the piston, the switchable solenoid valve must be so that during pressure build-P to no volume of brake fluid from the brake circuits BK1, BK2 conveyed back into the pressure chamber with the larger effective piston area.
  • the switchable solenoid valve whereby, for example brake fluid volume over open switching valves SV1, SV2, SV3, SV4, opened bypass switching valves BPI, in the embodiment in Fig.
  • FIG. 4a shows a further embodiment in which all check valves (RV3, RV4, RV5, RV6) are replaced by solenoid valves.
  • the brake circuits can be connected by a bypass switching valve BPI or by a series connection of two bypass switching valves BPI, BP2. In the embodiment in FIG.
  • the individual master cylinder which can also have a force displacement sensor KWS in the piston for the purpose of pedal force measurement, can also be connected directly to the first brake circuit BK1 via the feed switching valve FV, for example.
  • a redundant central outlet switching valve ZAV2 can be used, which is connected to the first brake circuit BK1, for example.
  • FIG. 4b shows a further embodiment which, compared to FIG. 4a, has a tandem cylinder THZ instead of a single master cylinder SHZ.
  • the piston 3 of the brake pedal device can be coupled via a first pressure chamber and a first return spring RF to a second, so-called floating piston SK, which in turn can be moved in a further pressure chamber against a second return spring RF3.
  • a first pressure chamber between the piston 3 and the floating piston SK of the tandem master cylinder THZ can be connected to the hydraulic line between the first bypass switching valve BPI and the central outlet switching valve ZAV via a hydraulic output and a first feed switching valve FV.
  • the path simulator WS can be connected to the tandem master cylinder TITZ via, for example, a further hydraulic output of the first pressure chamber and, if present, the path simulator separating valve 14.
  • the second pressure chamber of the tandem master cylinder TITZ can also be connected to the second brake circuit BK2 via a further hydraulic output and a second feed switching valve FV2 as well as possible further valves, the second feed switching valve FV2 for a fallback level preferably being designed as a normally open solenoid valve.
  • Both pressure chambers of the tandem master cylinder TITZ can each have a sniffer opening or opening which, for example, is sealed by at least one primary (D2, D5) and secondary di rectification (Dl, D4) and each, for example, as in FIG a throttle and a non-return valve closing towards the reservoir VB can be connected to the reservoir VB.
  • the hydraulic connections between the pressure chambers of the tandem master cylinder and the storage tank VB can also be used, as in Fig. 1b, Fig. 3b, via diagnostic valves (V D ) or, as in Fig. take place via a hydraulic line.
  • FIG. 5b shows a further embodiment which, compared to FIG. 5a, has a tandem master cylinder THZ with a tappet.
  • the piston 3 of the brake pedal device can be moved in a first pressure chamber between the piston 3 and the floating piston SK and coupled to a further tappet and a further piston, which in turn can be moved into a second pressure chamber against a return spring.
  • the hydraulic connection and the function of this tandem master cylinder THZ is as in FIG. 5a.
  • the check valve RV3 is connected to the back space of the floating piston SK via a further hydraulic line and a further opening in the tandem master cylinder.
  • Drl, Dr4 throttle in the connection between the main cylinder and the storage tank
  • Valve plate 21 Force-travel characteristic for the brake pedal KA piston stop

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Regulating Braking Force (AREA)

Abstract

L'invention concerne un système de freinage pour un véhicule, qui comprend un système de pédale de frein hydraulique comprenant un maître-cylindre ayant au moins une chambre de pression, dont une sortie hydraulique est couplée de manière commutable à au moins un circuit de freins par l'intermédiaire d'une soupape de commutation d'alimentation, et le maître-cylindre étant couplé à un réservoir par l'intermédiaire d'au moins une ouverture par l'intermédiaire d'une liaison hydraulique. Selon l'invention, un joint d'étanchéité de chambre de pression de la ou des chambres de pression du maître-cylindre est protégé contre une défaillance par au moins un élément redondant et la défaillance du joint d'étanchéité de chambre de pression ou de l'élément redondant du joint d'étanchéité de chambre de pression de la ou des chambres de pression du maître-cylindre peut être diagnostiquée.
PCT/EP2020/072284 2020-02-12 2020-08-07 Système de freinage à sûreté intégrée WO2021160298A1 (fr)

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DE112020006702.5T DE112020006702A5 (de) 2020-02-12 2020-08-07 Ausfallsicheres bremssystem

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EPPCT/EP2020/053668 2020-02-12
PCT/EP2020/053667 WO2020165295A1 (fr) 2019-02-12 2020-02-12 Système de freinage à sécurité intégrée
EPPCT/EP2020/053667 2020-02-12
EPPCT/EP2020/053666 2020-02-12
PCT/EP2020/053666 WO2020165294A2 (fr) 2019-02-12 2020-02-12 Système de freinage résistant aux défaillances
PCT/EP2020/053668 WO2020165296A1 (fr) 2019-02-12 2020-02-12 Dispositif d'alimentation en pression pourvu de pistons à double effet pour un système de freinage

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PCT/EP2020/072269 WO2021160296A1 (fr) 2020-02-12 2020-08-07 Système de freinage
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DE102022123532A1 (de) 2022-09-14 2024-03-14 Heinz Leiber Bremssystem sowie Ventil mit zuschaltbarer Haltekraft

Citations (5)

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Publication number Priority date Publication date Assignee Title
DE4340467A1 (de) * 1993-11-27 1995-06-01 Bosch Gmbh Robert Mit Fremdkraft arbeitende hydraulische Fahrzeugbremsanlage
DE102010050132A1 (de) 2010-11-03 2012-05-03 Ipgate Ag Betätigungsvorrichtung mit Wegsimulator
DE102013217954A1 (de) * 2013-09-09 2015-03-12 Continental Teves Ag & Co. Ohg Bremsanlage für ein Kraftfahrzeug und Betriebsverfahren
US20170106843A1 (en) * 2015-10-19 2017-04-20 Mando Corporation Method for diagnosing electric brake system
WO2019215032A1 (fr) * 2018-05-09 2019-11-14 Ipgate Ag Système de freinage

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10688979B2 (en) * 2015-03-16 2020-06-23 Ipgate Ag Brake system with floating piston-main brake cylinder unit with a novel type of MUX control (MUX 2.0) with at least one outlet valve, and method for regulating pressure

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4340467A1 (de) * 1993-11-27 1995-06-01 Bosch Gmbh Robert Mit Fremdkraft arbeitende hydraulische Fahrzeugbremsanlage
DE102010050132A1 (de) 2010-11-03 2012-05-03 Ipgate Ag Betätigungsvorrichtung mit Wegsimulator
DE102013217954A1 (de) * 2013-09-09 2015-03-12 Continental Teves Ag & Co. Ohg Bremsanlage für ein Kraftfahrzeug und Betriebsverfahren
US20170106843A1 (en) * 2015-10-19 2017-04-20 Mando Corporation Method for diagnosing electric brake system
WO2019215032A1 (fr) * 2018-05-09 2019-11-14 Ipgate Ag Système de freinage

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DE112020006706A5 (de) 2023-01-26
DE112020006702A5 (de) 2022-12-01
WO2021160297A1 (fr) 2021-08-19
WO2021160296A1 (fr) 2021-08-19

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