WO2022161654A1 - Verfahren zur steuerung einer elektronisch schlupfregelbaren fremdkraftbremsanlage mit redundanter bremsdruckerzeugung - Google Patents
Verfahren zur steuerung einer elektronisch schlupfregelbaren fremdkraftbremsanlage mit redundanter bremsdruckerzeugung Download PDFInfo
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- WO2022161654A1 WO2022161654A1 PCT/EP2021/080313 EP2021080313W WO2022161654A1 WO 2022161654 A1 WO2022161654 A1 WO 2022161654A1 EP 2021080313 W EP2021080313 W EP 2021080313W WO 2022161654 A1 WO2022161654 A1 WO 2022161654A1
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- pressure
- brake
- pressure medium
- delivery device
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- 238000000034 method Methods 0.000 title claims abstract description 45
- 230000009467 reduction Effects 0.000 claims description 42
- 230000004913 activation Effects 0.000 claims description 8
- 238000006073 displacement reaction Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 abstract description 2
- 238000007599 discharging Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 21
- 230000000875 corresponding effect Effects 0.000 description 10
- 230000008569 process Effects 0.000 description 6
- 230000001276 controlling effect Effects 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 210000003205 muscle Anatomy 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- 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
- B60T8/34—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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
- B60T17/18—Safety devices; Monitoring
- B60T17/22—Devices for monitoring or checking brake systems; Signal devices
- B60T17/221—Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems
- B60T17/222—Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems by filling or bleeding of hydraulic systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/40—Failsafe aspects of brake control systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
- B60Y2400/00—Special features of vehicle units
- B60Y2400/81—Braking systems
Definitions
- the invention relates to a method for controlling an electronically slip-controllable power brake system with redundant brake pressure generation according to the features of the preamble of claim 1.
- externally powered brake systems can have a hydraulic fallback level in addition to their brake pressure supply. Even in the event of a failure of the power supply and/or the electronics, this allows the driver to build up conventional braking pressure using muscle power.
- FIG. 1 shows a hydraulic layout, known from the prior art, of an electronically slip-controllable power brake system with redundant brake pressure generation, as is the basis for the following invention.
- This known power brake system (10) includes, among other things, a braking request detection device, via which a braking request can be specified by the driver.
- a master brake cylinder (14) that can be actuated via a pedal (12) and has, for example, two pressure chambers (16a, 16b). The latter are each connected to a brake circuit (18a, 18b).
- braking pressure can be built up by muscle power via the master brake cylinder (14).
- One of the pressure chambers (16a) is also connected to a pedal feel simulator (20), which provides the driver with haptic feedback when the pedal (12) is actuated.
- the externally powered brake system (10) also has a brake pressure generator (22) with a first pressure medium delivery device (24) for building up a brake pressure that correlates with the specified braking request. There is also a brake pressure modulator (26) with a second pressure medium delivery device (28) for wheel-specific control of the brake pressure.
- the pressure medium conveying devices (24, 28) are arranged together with associated directional control valves in hydraulic units (30a, 30b), which are physically separate from one another in the embodiment variant shown, but are in hydraulic contact with one another.
- Both the brake pressure generator (22) and the brake pressure modulator (26) can be supplied with hydraulic pressure medium via a common reservoir (32) of the power brake system (10) arranged on the master brake cylinder (14).
- the brake pressure generator (22) and the brake pressure modulator (26) are connected in parallel to the two brake circuits (18a, 18b).
- a plurality of wheel brakes (34 ad) are in contact with these brake circuits (18a, 18b).
- a large number of directional control valves are provided to control pressure medium connections between the components of the externally powered brake system (10).
- An electrically controllable simulator valve (36) is provided to control the connection of the master brake cylinder (14) to the pedal feel simulator (20).
- Circuit separating valves (38a, 38b) are also present, each of which controls a connection between a pressure chamber (16a, 16b) of the master brake cylinder (14) and an associated brake circuit (18a, 18b). These circuit separating valves (38a, 38b) are normally open and block this connection in the electrically controlled state, ie in the normal state of the power brake system (10).
- a provided plunger outlet valve (40) couples the first pressure medium delivery device (24) controllably to the reservoir (32) of the power brake system (10). This plunger outlet valve (40) is closed in the basic position and opens the corresponding pressure medium connection in the electrically controlled state.
- Plunger isolation valves (42a, 42b) are also provided to control a pressure medium connection from the first pressure medium delivery device (24) to one of the brake circuits (18a, 18b). They are open in the electrically controlled state.
- a so-called circuit pressure control valve (44a, 44b) is provided for each brake circuit (18a, 18b).
- the valve is a normally open valve that can be actuated in the closing direction by electrical control.
- High-pressure switching valves (46a, 46b) are arranged in parallel with the circuit pressure control valves (44a, 44b). They are used to control the supply of the second pressure medium delivery device (28) with pressure medium from the reservoir (32). They are normally closed.
- Each wheel brake (34a-d) is also assigned a controllable pressure build-up valve (48a-d) and a similar pressure reduction valve (50a-d) for the wheel-specific adjustment of the brake pressure.
- valves mentioned are designed either as switching or as control valves. Switching valves take either one or the other valve position, while control valves can also be placed in intermediate positions to throttle the flow of pressure medium if necessary.
- the controllability of a directional control valve can be seen in the symbolic representation of the directional control valves in FIG. 1 using a valve actuator provided with a diagonal arrow.
- the circuit pressure control valves (44a, 44b) and the pressure build-up valves (48a-d) are designed as control valves; the other valves are switching valves.
- the power brake system (10) also includes electronic control units (52a, 52b) which are assigned to the brake pressure generator (22) or the brake pressure modulator (26). They control the respective pressure medium conveying devices and/or the valves explained as required and, for this purpose, record signals from sensors which record the driving status of the vehicle, the current traffic situation and/or measured variables within the power brake system (10).
- a path measuring sensor (64) of the power brake system (10) which detects an actuation path of the pedal (12) and also to pressure sensors (61a, 61b) for detecting the pressure from the master brake cylinder (14) or from the first Pressure medium conveyor (24) generated pressures.
- the two control units (52a, 52b) communicate electronically with one another. They can also be combined into an electronic control unit.
- the first pressure medium conveying device (24) of the brake pressure generator (22) is a plunger piston (54) or displacer which is movably accommodated in a plunger cylinder (56) and guided axially therein.
- the plunger piston (54) can be displaced by an electric drive (58) within the plunger cylinder (56) in a pressure build-up direction or in a pressure reduction direction directed opposite thereto.
- the movement of the displacer ends in the pressure build-up direction at a so-called outer reversal point and in the pressure reduction direction at a so-called inner reversal point.
- the volume of a working chamber (60) enclosed by the plunger piston (54) and the plunger cylinder (56) changes with the movement of the plunger piston.
- the volume of the working chamber (60) decreases when the plunger (54) moves in the pressure-increasing direction and conversely increases when the plunger (54) moves in the pressure-reducing direction.
- a pressure-volume characteristic of the externally powered brake system (10) indicates a pressure change in the connected brake circuit (18a, 18b) as a function of the volume of pressure medium displaced by this first pressure medium delivery device (24).
- the characteristic curve is largely determined structurally by the design of the brake circuit (18a, 18b) and the dimensions of the plunger piston (54) or the plunger cylinder (56) of the first pressure medium delivery device (24) and is stored digitally in the electronic control unit (52).
- the second pressure medium conveying device (28), on the other hand, is a pump that conveys pressure medium continuously or in cycles.
- it can therefore be a piston or gear pump, which is also driven by an electrically controllable motor (62).
- a braking request requires the setting of a brake pressure that is higher than a maximum pressure p(max) that can be provided by the brake pressure generator alone.
- This maximum pressure is through the power of the drive (58) of the displacer and the volume of the working chamber (60) set.
- the second pressure medium delivery device (28) of the brake pressure modulator (26) is used to boost the existing brake pressure.
- the second pressure medium delivery device (28) is put into operation or driven.
- a relief line could be provided which connects the working chamber (60) of the plunger cylinder (56) to the reservoir (32) and is opened by the plunger piston (54) as soon as it has reached or passed its inner reversal point. Nevertheless, the brake pressure reduction would then also take place abruptly and cause an uncomfortable drop in vehicle deceleration and unwanted operating noise.
- the invention therefore proposes a method with which this residual pressure in the brake circuit (18a, 18b) can be reduced in a controlled manner using the existing components. Potential operating noises are avoided, without the need for additional pressure medium-controlling components or modifications to the existing components.
- the proposed method is implemented in terms of control technology and can therefore be implemented in a particularly cost-effective manner.
- the drawing includes a total of 4 figures, of which the
- Invention underlying power brake system (10) shows in a starting position
- FIG. 4 shows an alternative method to the method according to FIG. 2 using diagrams in FIGS. 4a - 4d.
- the power brake system (10) shown in FIG. 1 forms the basis of the method according to the invention explained below. Their structure and function have already been discussed in the introduction to the description.
- the power brake system (10) is in an active mode, ie the power supply is intact and there are no mechanical faults in the components. Consequently, the directional control valves assume the positions shown in FIG. Accordingly, the simulator valve (36), ie the valve in the pressure medium connection from a pressure chamber (16a, 16b) of the master brake cylinder (14) to a pedal feel simulator (20), is open.
- the circuit isolating valves (38a, 38b) for controlling pressure medium connections of the pressure medium chambers (18a, 18b) of the master brake cylinder (14) with the brake circuits (18a, 18b) are in the blocked position.
- the driver is therefore decoupled from the generation of brake pressure in the wheel brakes (34a-d) and simply specifies the braking request by actuating the pedal (12).
- the braking request is determined by means of the path measuring sensor system (64), which detects a path covered by the pedal (12), converts it into an electronic signal and transmits it to the electronic control unit (52a).
- the plunger outlet valve (40) is closed and thus the pressure medium connection of the first pressure medium delivery device (24) to the reservoir (32) is blocked, while the plunger isolating valves (42a, 42b) are open and the circuit pressure control valves (44a, 44b) are closed. At least one of the wheel brakes (34a - 34d) is subjected to braking pressure.
- the plunger piston (54) of the brake pressure generator (22) has been actuated by its drive (58) in the pressure build-up direction and is therefore located at its outer reversal point in the plunger cylinder (56). Consequently, the working chamber (60) has a minimal volume.
- the second brake pressure delivery device (28) of the brake pressure modulator (26) sucked in additional volume from the reservoir (32) to increase the brake pressure and delivered it to the at least one brake circuit (18a, 18b).
- This is done via an existing pressure medium connection, which, starting from the reservoir (32), via a check valve (66) placed downstream of this reservoir and via the electrically controlled and therefore open high-pressure switching valve (46a, 46b), leads to the suction side of this second pressure medium delivery device (28).
- the pressure build-up valves (48a-d) assigned to the wheel brakes (34a-d) are open and the pressure reduction valves (50a-d) are closed.
- the delivery of additional pressure medium by the second pressure medium delivery device (28) may have taken place, for example, because it had become necessary during a braking operation to adapt the brake pressure in the wheel brakes (32a-d) to the slip conditions on one or more wheels of the vehicle and/or because the brake pressure generator (22) had displaced the maximum possible volume of pressure medium without being able to set the brake pressure corresponding to the braking request.
- this constellation has meant that the pressure-volume characteristic curve of the externally powered brake system (10), which is inherently constructively fixed, has shifted towards higher pressures. This characteristic curve shift is reversed in a controlled manner with the procedure described below.
- FIG. 2 comprises a total of four diagrams 2a-2d arranged one above the other, which show the course of parameters relevant to the method in a time-synchronous manner with respect to one another.
- the uppermost diagram 2a of FIG. 2 represents pressure profiles. It shows a total of two characteristic curves, of which a first pressure characteristic curve (68a) shows the time profile of the pressure in the working chamber (60) of the first pressure medium delivery device (24), i.e. the brake pressure generator ( 22), while the second pressure characteristic curve (68b) illustrates the course of the brake pressure in one of the wheel brakes (34a-d) and thus, in a figurative sense, the specified braking request.
- a first pressure characteristic curve (68a) shows the time profile of the pressure in the working chamber (60) of the first pressure medium delivery device (24), i.e. the brake pressure generator ( 22)
- the second pressure characteristic curve (68b) illustrates the course of the brake pressure in one of the wheel brakes (34a-d) and thus, in a figurative sense, the specified braking request.
- a first volume characteristic (70a) indicates the volume displaced by the first pressure medium delivery device (24), i.e. the brake pressure generator (22), and the second volume characteristic (70b) indicates the volume displaced by the second pressure medium delivery device (28), i.e the brake pressure modulator (26).
- diagram 2b with the signal characteristic (72) also illustrates the electrical activation of the plunger outlet valve (40) in the pressure medium connection of the first pressure medium delivery device (24) to the reservoir (32). Since this is a normally closed switching valve, this signal characteristic (72) indicates when the plunger outlet valve (40) is electrically controlled and thus opened.
- FIG. 2c shows the differential pressure curve (74) over time of a differential pressure which is applied to the circuit pressure control valve (44a, 44b) of a brake circuit (18a, 18b).
- This differential pressure corresponds to the pressure difference between the pressure at a pressure medium inlet and a pressure medium outlet of this circuit pressure control valve (44a, 44b), with the pressure medium inlet facing the wheel brake (34a-d) due to the flow direction of the pressure medium, while the pressure medium outlet faces the first pressure medium delivery device (24). is. If the displayed differential pressure is high, the circuit pressure control valve (44a, 44b) has a relatively small or no throttle cross section and if the differential pressure is zero, the circuit pressure control valve (44a, 44b) is in the open position.
- time axes in the diagrams in FIG. 2 are each subdivided into a total of 6 time phases, which are numbered t1 to t6.
- a pressure build-up takes place in at least one wheel brake (34a-d) of a brake circuit (18a, 18b) in a first time phase t1.
- This pressure build-up takes place steadily and evenly, i.e. along a straight ramp that rises from bottom left to top right.
- the pressure medium volume is conveyed to the wheel brake (34a-d) by the first pressure medium conveying device (24), ie the brake pressure generator (22).
- the circuit pressure control valve (44a, 44b) is not electrically controlled and is therefore open, so that, according to FIG. 2c, there is no differential pressure at this directional control valve.
- the second pressure medium delivery device (28) of the brake pressure modulator (26) is not required during this first time phase t1.
- Your drive (58) is not electrically controlled and consequently its speed, according to FIG. 2d, is zero.
- the brake pressure already prevailing in the wheel brake (34a-d) is increased.
- the pressure medium required for this can no longer be made available by the first pressure medium delivery device (24) of the brake pressure generator (22) because its displacer has already reached its outer reversal point or is close to this outer reversal point. Consequently, the electronic control unit (52a) of the brake pressure generator (22) sends a corresponding request signal to the electronic control unit (52b) of the brake pressure modulator (26). This then controls the motor (62) of the second pressure medium delivery device (28). According to FIG. 2d, the motor (62) rotates, for example, at a constant speed and drives the second pressure medium delivery device (28) accordingly. That conveys a constantly increasing volume of pressure medium to the affected wheel brake (34a-d) (diagram 2b) and the pressure in this wheel brake (34a-d) increases to a maximum (diagram 2a).
- the pressure in the brake circuit (18a, 18b) or in the wheel brake (34a-d) connected to it is controlled by electrical actuation of the circuit pressure control valve (44a, 44b). For this purpose, this successively reduces the throttle cross-section down to zero, as a result of which the pressure drop between its pressure medium inlet and its pressure medium outlet, as can be seen in FIG. 2c, rises uniformly to a maximum.
- the pressure in the working chamber (60) of the first pressure medium delivery device (24) drops to atmospheric pressure level (diagram 2a). The reason for this is that the second pressure medium delivery device (28), i.e.
- the brake pressure modulator (26) draws in the pressure medium required for the pressure build-up from the reservoir (32) and the corresponding suction path via the open plunger isolation valve (42a, 42b) is connected to this first pressure medium delivery device ( 24) is connected. Atmospheric pressure prevails in the reservoir (32). Due to the pressure medium being conveyed to the wheel brake (34a-d) by the second pressure medium conveying device (28), the pressure-volume characteristic of the externally powered brake system (10) no longer matches the structurally specified pressure-volume characteristic of the first pressure medium conveying device (24). As explained above, the latter has shifted towards higher pressures. This condition can be determined by the electronic control unit (52a, 52b) of the power brake system (10) as part of a regular check of the characteristics.
- the measured actual value for the brake pressure and the actual value for the pumped pressure medium volume calculated from the operating parameters of the brake pressure generator (22) were compared with the known target values of the structurally specified pressure-volume characteristic curve of the first pressure medium pumping device (24). If the discrepancy found is greater than a specified limit value, this discrepancy is not tolerable and must be corrected. More on that later.
- the throttling effect of the circuit pressure control valve (44a, 44b) is regulated in time phase t3.2 in such a way that a pressure level is set in the working chamber (60) which, according to the illustration, corresponds to the maximum pressure p(max) that the first pressure medium delivery device (24) can build up at all due to the design in the brake circuit (18a, 18b).
- P(max) is entered in FIG. 2a as a horizontal line. Instead of p(max), any pressure lower than p(max) could also be set.
- the circuit pressure control valve (44a, 44b) is brought into its open position in a controlled manner, i.e. its electrical activation is abandoned. Pressure medium from the wheel brake (34a-d) thus flows into the working chamber (60) of the first pressure medium delivery device (24).
- the drive (58) of the first pressure medium conveying device (24) is electrically activated and the displacer is thus actuated in the pressure reduction direction, ie in the direction of its inner reversal point.
- this displacer-controlled pressure reduction phase continues through actuation of the drive (58) of the first pressure medium delivery device (24) in the direction of the inner reversal point.
- the pressure reduction follows unchanged the ramp function explained above and can be seen from the diagram in FIG. 2a.
- the circuit pressure control valve (44a, 44b) is electrically activated again on the basis of this incoming electronic information.
- the circuit pressure control valve (44a, 44b) is brought into a throttle position by the corresponding control signal, in which the set throttle cross section corresponds to a brake pressure assigned to the position of the plunger piston (54) in the plunger cylinder (56).
- the plunger outlet valve (40) is controlled in parallel and is thus brought from its blocked position into its open position.
- this pressure reduction could in principle also be controlled via the movement of the plunger piston (54).
- the retracting plunger (54) travels over the orifice and only fully releases the relief line when it has reached the inner reversal point.
- This differential pressure is now gradually reduced to zero or to the present driver's braking request by a linear change in the electrical actuation of this circuit pressure control valve (44a, 44b) by the electronic control unit (52b), see FIG. 2c.
- this circuit pressure control valve (44a, 44b) gradually releases its maximum throttle cross section again until finally the residual pressure remaining in the brake circuit (18a, 18b) has been completely reduced according to the diagram in FIG. 2a.
- This reduction in brake pressure also takes place steadily or continuously, so that its previous course continues without transition. As a result, there are no noises or changes in deceleration that can be perceived by the vehicle occupants.
- the brake pressure modulator (26) returns to its passive state and any subsequent renewed build-up of brake pressure becomes conventional again, i.e. through an adapted electrical activation of the drive (58) of the first pressure medium delivery device (24) or the brake pressure generator (22) controlled.
- step (80) the deviation between the structurally specified pressure-volume target characteristic and the pressure-volume actual characteristic of the power brake system is determined. Various methods can be used for this.
- the actual value of a brake pressure is measured by means of the pressure sensor (61) in the brake circuit (18b) and compared with a target brake pressure.
- the desired brake pressure can be derived from the braking request and thus from the displacement signal of the displacement sensor system (64) coupled to the pedal (12) via the known pressure-volume characteristic curve of a power brake system (10). If this comparison reveals a discrepancy, the volume of pressure medium that has been additionally displaced into the brake circuit (18a, 18b) by the second pressure medium delivery device (28) is determined from the detected deviation via the known pressure-volume characteristic.
- the volume of pressure medium additionally displaced by the second pressure medium delivery device (28) can also be determined from the actuation time of the motor (62). for driving the second pressure medium delivery device (28) multiplied by the speed of the motor (62) and the known value of the volume of pressure medium displaced per revolution of the motor (62).
- Information about when and for how long the second pressure medium delivery device (28) was actuated can be derived from the request signal, which the control unit (52a) of the brake pressure generator (22) sent to the control unit (52b) of the brake pressure modulator (26).
- this value is compared with a definable limit value (88) in the following second step (82). Below this limit value, there is no need to carry out the method described, since the influence of the additionally displaced volume of pressure medium on the pressure-volume characteristic is then tolerable.
- the control method explained above or the alternative control method explained below is carried out, this being carried out as part of a braking process in progress, specifically when in the course of this braking process, the braking request is withdrawn.
- the implementation of the method is illustrated in FIG. 3 using the symbol with the reference number (86).
- FIGS. 4a-4d The alternative method mentioned for controlling a power brake system (10) with redundant generation of brake pressure is illustrated using a total of four diagrams in FIGS. 4a-4d. Comparable to those in FIG. 2, these diagrams are recorded synchronously with one another, divided into several time phases and represent the same course parameters, each plotted over time.
- braking pressure is also built up here by actuating the first pressure medium delivery device (24).
- the plunger outlet valve (40) is closed, the circuit pressure control valve (44a, 44b) is open, so that there is no differential pressure (FIG. 4c).
- the motor (62) of the second pressure medium delivery device (28) is not electrically controlled and therefore does not rotate.
- the existing brake pressure is increased during the second time phase t2.
- the pressure medium required for this is supplied by the second pressure medium delivery device (28), as can be seen from the volume characteristic in the diagram according to FIG. 4b and the speed characteristic of the motor (62) of the second pressure medium delivery device (28) according to FIG. 4d.
- the plunger outlet valve (40) is actuated electrically and thus opens the pressure medium connection of the first pressure medium delivery device (24) to the reservoir (32).
- the pressure in the working chamber (60) of the first pressure medium delivery device (24) and thus also at the pressure medium outlet of the circuit pressure control valve (44a, 44b) then returns to atmospheric pressure.
- the pressure difference dropping across these circuit pressure control valves (44a, 44b) is adjusted by an adapted electrical activation of the circuit pressure control valves (44a, 44b). Its amount depends on the brake pressure in the wheel brake (34a-d) or on the pressure present at the pressure medium inlet of this directional control valve.
- the brake pressure is continuously increased until it is higher than a maximum pressure p(max) that can be adjusted by the first pressure medium delivery device (24) in the brake circuit (18a, 18b) due to the design.
- the volume of pressure medium required for this is also provided by the second pressure medium delivery device (28), which is driven for this purpose (see FIGS. 4b and 4d).
- the differential pressure at the circuit pressure control valve (44a, 44b) also increases (FIG. 4c).
- Braking changes in the time phase t3 are corrected by electrically activating the circuit pressure control valve (44a, 44b).
- the circuit pressure control valve (44a, 44b) In connection with the plunger outlet valve (40), which is still open, pressure medium is discharged from the wheel brake (34a-d) via the first pressure medium delivery device (24) into the reservoir (32) of the power brake system (10) in the event of a pressure reduction, or in the event of a pressure build-up Pressure medium is drawn in from the second pressure medium delivery device (28) via the open high-pressure switching valve (46a, 46b) from the reservoir (32) and displaced to the wheel brake (34a-d).
- the circuit pressure control valve (44a, 44b) is understandably closed.
- pressure medium is drawn from the wheel brake(s) (34a-d) via the open or partially open circuit pressure control valve (44a, 44b), the working chamber (60) of the first pressure medium delivery device (24) and the plunger outlet valve (40), which is also open Drained reservoir (32).
- the brake pressure reduction is regulated by continuously adapting the corresponding electrical actuation of the circuit pressure control valve (44a, 44b) and is accordingly also referred to as the valve-controlled pressure reduction phase.
- the volume of the working chamber (60) is sufficient to fill the volume of pressure medium in the plunger cylinder (56).
- the electrical actuation of the plunger outlet valve (40) is withdrawn at the end of the time phase t4 to fully absorb the brake circuit (18a, 18b) for a further brake pressure reduction to zero.
- the plunger outlet valve (40) thus returns to its closed position and interrupts the pressure medium connection of the first pressure medium delivery device (24) to the reservoir (32).
- the electrical activation of the circuit pressure control valve (44a, 44b) is canceled.
- the further brake pressure reduction takes place in the time phase t5 by actuating the drive (58) of the first pressure medium delivery device (24) or by driving the plunger piston (54) in the pressure reduction direction. If this displacer has reached its inner reversal point, the brake pressure has reached zero and the pressure-volume characteristic of the power brake system (10) again agrees with the pressure-volume characteristic of the first pressure medium delivery device (24).
- the brake pressure would be reduced under valve control to the pressure level which corresponds to the corresponding position of the plunger piston (54) in the plunger cylinder (56) according to the known pressure-volume characteristic curve of the power brake system (10). Any residual pressure then still present in the brake circuit (18a, 18b) could then be reduced to atmospheric pressure by further retracting the displacer of the brake pressure generator (22) to its inner reversal point.
- FIGS. 2 and 4 show braking processes in which the braking pressure corresponding to the braking request is higher than the maximum pressure p(max), which is generated by the first pressure medium delivery device (24) in the brake circuit (18a, 18b). can.
- the latter is not a prerequisite for carrying out the method explained, since in power brake systems (10) braking processes can also occur in which the second pressure medium delivery device (28) pressure medium has been delivered to the brake circuit (18a, 18b) without this maximum pressure that can be provided by the first pressure medium delivery device (24) being reached.
- the trigger for carrying out the method on which the invention is based is therefore not the brake pressure in the brake circuit (18a, 18b), but rather the volume of pressure medium that has been pumped from the second pressure medium delivery device (28) into the brake circuit (18a, 18b) to generate the brake pressure .
- the method does not need to be carried out if this volume has a value below a limit value that can be set in the electronic control unit (52a, 52b). In this case, the deviation of the pressure-volume characteristic of the power brake system (10) from the pressure-volume characteristic of the first pressure medium delivery device (24) is still tolerable.
- a brake pressure reduction in a brake circuit (18a, 18b) of a power brake system (10) with redundant pressure supply includes a valve-controlled pressure reduction phase in which pressure medium is controlled by an electrical activation of a circuit pressure control valve (44a , 44b) to the reservoir (32).
- the pressure medium connection to the reservoir (32) can be routed via a line in which the plunger outlet valve (40) is located or via a relief line whose opening into the working chamber (60) is controlled by the plunger piston (54).
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Regulating Braking Force (AREA)
- Braking Systems And Boosters (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2023544597A JP2024503920A (ja) | 2021-01-27 | 2021-11-02 | 冗長なブレーキ圧力発生を伴う電子式にスリップコントロール可能な非人力ブレーキ装置を制御する方法 |
US18/261,573 US20240083401A1 (en) | 2021-01-27 | 2021-11-02 | Method for controlling an electronically slip-controllable power-brake system with redundant generation of brake pressure |
KR1020237028608A KR20230135633A (ko) | 2021-01-27 | 2021-11-02 | 중복식 제동 압력 생성에 의한 전자식으로 슬립 제어가능한 외부 동력식 브레이크 시스템을 제어하기 위한 방법 |
CN202180092007.9A CN116745182A (zh) | 2021-01-27 | 2021-11-02 | 用于控制具有冗余的制动压力生成的以电子方式滑差可调的助力制动系统的方法 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE102021200697.3 | 2021-01-27 | ||
DE102021200697.3A DE102021200697A1 (de) | 2021-01-27 | 2021-01-27 | Verfahren zur Steuerung einer elektronisch schlupfregelbaren Fremdkraftbremsanlage mit redundanter Bremsdruckerzeugung |
Publications (1)
Publication Number | Publication Date |
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WO2022161654A1 true WO2022161654A1 (de) | 2022-08-04 |
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ID=78528950
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/EP2021/080313 WO2022161654A1 (de) | 2021-01-27 | 2021-11-02 | Verfahren zur steuerung einer elektronisch schlupfregelbaren fremdkraftbremsanlage mit redundanter bremsdruckerzeugung |
Country Status (6)
Country | Link |
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US (1) | US20240083401A1 (de) |
JP (1) | JP2024503920A (de) |
KR (1) | KR20230135633A (de) |
CN (1) | CN116745182A (de) |
DE (1) | DE102021200697A1 (de) |
WO (1) | WO2022161654A1 (de) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102013224870A1 (de) * | 2013-03-05 | 2014-09-11 | Continental Teves Ag & Co. Ohg | Bremsbetätigungseinheit |
KR20140135043A (ko) * | 2013-05-15 | 2014-11-25 | 현대모비스 주식회사 | Esc 통합형 제동 시스템 |
DE102015201331A1 (de) * | 2015-01-27 | 2016-07-28 | Continental Teves Ag & Co. Ohg | Verfahren zum Betrieb einer Bremsanlage sowie Bremsanlage |
-
2021
- 2021-01-27 DE DE102021200697.3A patent/DE102021200697A1/de active Pending
- 2021-11-02 WO PCT/EP2021/080313 patent/WO2022161654A1/de active Application Filing
- 2021-11-02 CN CN202180092007.9A patent/CN116745182A/zh active Pending
- 2021-11-02 KR KR1020237028608A patent/KR20230135633A/ko unknown
- 2021-11-02 US US18/261,573 patent/US20240083401A1/en active Pending
- 2021-11-02 JP JP2023544597A patent/JP2024503920A/ja active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102013224870A1 (de) * | 2013-03-05 | 2014-09-11 | Continental Teves Ag & Co. Ohg | Bremsbetätigungseinheit |
KR20140135043A (ko) * | 2013-05-15 | 2014-11-25 | 현대모비스 주식회사 | Esc 통합형 제동 시스템 |
DE102015201331A1 (de) * | 2015-01-27 | 2016-07-28 | Continental Teves Ag & Co. Ohg | Verfahren zum Betrieb einer Bremsanlage sowie Bremsanlage |
Also Published As
Publication number | Publication date |
---|---|
CN116745182A (zh) | 2023-09-12 |
JP2024503920A (ja) | 2024-01-29 |
US20240083401A1 (en) | 2024-03-14 |
DE102021200697A1 (de) | 2022-07-28 |
KR20230135633A (ko) | 2023-09-25 |
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