CN109195843B - Method for operating a hydraulic brake system, hydraulic brake system - Google Patents
Method for operating a hydraulic brake system, hydraulic brake system Download PDFInfo
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- CN109195843B CN109195843B CN201780034438.3A CN201780034438A CN109195843B CN 109195843 B CN109195843 B CN 109195843B CN 201780034438 A CN201780034438 A CN 201780034438A CN 109195843 B CN109195843 B CN 109195843B
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- 238000000034 method Methods 0.000 title claims abstract description 25
- 230000006870 function Effects 0.000 description 16
- 230000000694 effects Effects 0.000 description 8
- 208000006011 Stroke Diseases 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 230000000875 corresponding effect Effects 0.000 description 5
- 238000000418 atomic force spectrum Methods 0.000 description 4
- 230000002596 correlated effect Effects 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 230000003416 augmentation Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 230000035807 sensation Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000004308 accommodation Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
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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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/662—Electrical control in fluid-pressure brake systems characterised by specified functions of the control system components
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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
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
- B60T13/686—Electrical control in fluid-pressure brake systems by electrically-controlled valves in hydraulic systems or parts thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T7/00—Brake-action initiating means
- B60T7/02—Brake-action initiating means for personal initiation
- B60T7/04—Brake-action initiating means for personal initiation foot actuated
- B60T7/042—Brake-action initiating means for personal initiation foot actuated by electrical means, e.g. using travel or force sensors
-
- 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
- B60T8/48—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 connecting the brake actuator to an alternative or additional source of fluid pressure, e.g. traction control systems
- B60T8/4809—Traction control, stability control, using both the wheel brakes and other automatic braking systems
- B60T8/4827—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems
- B60T8/4863—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Regulating Braking Force (AREA)
- Braking Systems And Boosters (AREA)
Abstract
The invention relates to a method for operating a hydraulic brake system (1) of a motor vehicle, wherein the brake system (1) has a brake pedal (2), a master brake cylinder (3) coupled to the brake pedal (2), and at least one brake circuit (4) having at least one wheel brake (9), wherein a brake force boost is automatically set as a function of a brake pedal actuation. It is provided that the brake force boost is generated at least by means of an operable booster (12) in the brake circuit (4) as a function of a brake pedal actuation on the one hand and as a function of the pressure of the hydraulic pressure in the master brake cylinder (3) or in the wheel brakes (9) on the other hand.
Description
The invention relates to a method for operating a hydraulic brake system of a motor vehicle, wherein the brake system has a brake pedal, a master brake cylinder coupled to the brake pedal, and at least one brake circuit having at least one wheel brake, wherein a brake boosting is automatically set as a function of a brake pedal actuation.
The invention further relates to a corresponding hydraulic brake system having at least one brake force intensifying device, by means of which a brake force intensification can be set.
Background
Methods and brake systems of the type mentioned at the outset are known from the prior art. Motor vehicles are usually equipped with a hydraulic brake system which allows the individual wheels to generate a braking force when the driver of the motor vehicle actuates a brake pedal. In general, a brake force booster, which is generally embodied as a vacuum brake force booster, is assigned to the master brake cylinder and introduces the force exerted by the driver on the brake pedal into the hydraulic brake system or into the hydraulic circuit in an increased manner, so that, for example, a legally required service braking effect is achieved. The brake force booster thus provides the necessary assistance force and at the same time produces a brake pedal sensation which is customary to the driver and has a clearly defined reaction force characteristic curve. This characteristic curve usually has a deceleration determined by the mechanical design of the vacuum brake booster before the perceptibly increased reaction force counteracts the driver. Such a time is also referred to as a jump time (JumpIn-Zeitpunkt) or jump effect (JumpIn-Effekt): at this moment, the reaction force rises accordingly.
The known vacuum brake booster furthermore ensures, according to its operating principle with respect to force support, that: despite the change in the volumetric capacity of the individual wheel brakes, there is always a correlation and reproducibility between the pedal force and the braking force or vehicle deceleration for the driver.
Disclosure of the invention
In the method according to the invention for operating a hydraulic brake system of a motor vehicle, which has a brake pedal, a master brake cylinder coupled to the brake pedal, and at least one brake circuit with at least one wheel brake, wherein a brake force boost is automatically set as a function of a brake pedal actuation, the method is characterized in that the brake force boost is generated at least by means of an actuatable pressure booster in the brake circuit as a function of a brake pedal actuation on the one hand and as a function of a hydraulic pressure in the master brake cylinder or in the wheel brake on the other hand.
This method has the advantage that the brake force boost can be generated by a controllable brake force booster device, that is to say by a brake force booster device which is mechanically decoupled from the brake pedal, without an undesirable feel for the driver occurring at the brake pedal. In particular, by the method according to the invention: a correlation between the pedal force and the vehicle deceleration is ensured so that the driver always obtains a reliable feeling when driving the vehicle. According to the invention, this is achieved by: the brake force boost is generated at least by means of an actuatable pressure booster in the brake circuit, on the one hand as a function of the brake pedal actuation and, on the other hand, as a function of the pressure of the hydraulic pressure in the master brake cylinder or in the wheel brakes. By actuating the pressure booster as a function of the brake pedal actuation on the one hand and as a function of the pressure in the master brake cylinder or in the wheel brakes on the other hand, it is ensured that: on the one hand, a desired volume is introduced into the individual wheel brakes in order to generate a desired braking force; on the other hand, the pressure in the master brake cylinder is maintained or adjusted in such a way that the driver has a familiar driving experience.
According to a preferred further development of the invention, it is provided that the brake pedal actuation is detected by means of a pedal travel sensor. It is therefore provided that the brake pedal operation is detected by a travel sensor. In this case, the pedal travel is measured and the pressure booster is actuated as a function thereof, in particular a target or target pressure for the master brake cylinder is determined therefrom, and a driver reaction force is determined therefrom.
For this purpose, it is preferably provided that the target pressure or the reaction force is determined as a function of the detected brake pedal actuation by means of a characteristic map and/or a characteristic curve.
Furthermore, a setpoint pressure for the wheel brakes is preferably determined as a function of the brake pedal actuation. The target pressure of the wheel brakes is thus determined by the brake pedal actuation or the detected pedal travel. This is achieved in particular alternatively or in addition to determining or determining the target pressure of the master brake cylinder. The respectively determined target pressures are used as target quantities in the actuation of the pressure booster, so that, in particular when only one of the target quantities is used (preferably the target pressure of the master brake cylinder, alternatively the target pressure of the wheel brakes), the target quantities are suitably adapted to achieve a correlated change of the two target quantities when the other, then not adjusted, target quantities have not been reached or exceeded.
Preferably, the pressure booster is actuated as a function of the actuation of the brake pedal as a function of the desired volumetric capacity of the wheel brake. Knowing the volume storage of the brake circuit, in particular of the wheel brakes, the pressure booster is actuated in such a way that the volume which is not required for the pressure build-up in the master brake cylinder is displaced into the brake circuit or into the individual wheel brakes. The pressure regulation taking into account the pressure in the master brake cylinder is preferably superimposed on the volume, during which both the actuation of the pressure booster and the actuation of one or more valves of the brake circuit are suitably adapted in order to maintain or adjust the pressure in the brake circuit and in the master brake cylinder in such a way that the desired brake pedal reaction force characteristic is achieved at the desired wheel pressure. The reaction force characteristic curve or the set pressure characteristic curve of the master brake cylinder with respect to the pedal travel should be formed such that the pedal force profile of the vacuum brake booster is simulated in order to provide the driver with a familiar pedal feel.
The pressure booster is actuated for this purpose as a function of a target pressure characteristic curve or setpoint pressure characteristic curve for the brake master cylinder or wheel brake, which provides the corresponding pedal feel.
The target pressure characteristic curve is preferably shifted by an offset value as a function of the idle stroke, in particular as a function of the prefill and/or air gap of the brake circuit. In particular, it is thereby achieved that the pressure in the master brake cylinder is maintained or kept at 0 bar until the jump-in time without pressure, and the reaction force then does not increase. A conventional pedal force profile which is desirable for the driver is thus achieved. The increase in the pedal force up to the jump force is preferably effected by elastic means, which are assigned in particular to the brake pedal. The offset value is in particular determined as the difference between the stroke of the predetermined hydraulic pressure, which is in particular reached at the end of the jump, and the stroke stored in the theoretical characteristic curve. The hydraulic pressure to be achieved does not necessarily have to be the pressure at the end of the jump, but can alternatively also be any hydraulic pressure below this value.
Furthermore, it is preferably provided that a stiffness factor of the brake circuit is determined in addition to the offset value and is applied to the target pressure characteristic curve. In particular, the target pressure characteristic curve is shifted by the offset value in such a way that the theoretical pressure and the actual pressure overlap at the jump point in time. Then, the stiffness coefficient is specifically determined by the quotient, and is converted back by the bias transition. From the stiffness coefficients, scaling coefficients are derived, which are applied to the target pressure characteristic curve, thereby resulting in a current target pressure characteristic curve. It is thus ensured that the pedal force and the wheel pressure/wheel movement are correlated as in conventional vehicles with vacuum brake force boosters, and that the stiffness of the brake system and the changed volume requirement only result in a change in the pedal travel at the desired deceleration.
The brake system according to the invention for a hydraulic brake system of a motor vehicle has a brake pedal, a master brake cylinder coupled to the brake pedal, and at least one brake circuit having at least one wheel brake, wherein at least one brake force booster device is assigned to the brake circuit. The brake system is characterized in that the brake force booster device has a controllable pressure booster, which is controlled by a specifically arranged controller, which is designed to: the supercharger is operated according to the method according to the invention. The advantages already mentioned arise in this case. The brake pedal is preferably assigned an elastic device which ensures that the braking force or the reaction force increases until the jump force is reached.
The master brake cylinder and/or the wheel brakes preferably each have at least one hydraulic pressure sensor for detecting the hydraulic pressure present in the master brake cylinder or in the wheel brakes.
Furthermore, it is preferably provided that a pedal travel sensor is assigned to the brake pedal, so that a brake pedal actuation is determined by monitoring the brake pedal movement and in particular the travel covered by the brake pedal.
It is also preferably provided that the brake circuit has at least one switchable valve which can be actuated between the master brake cylinder and the wheel brakes. The switching valve is open, in particular, in the currentless state, so that the brake pressure at the wheel brake can be increased at any time by the pedal actuation. If the switching valve is supplied with current, it closes the connection between the brake circuit and the master brake cylinder, so that pressure cannot escape from the brake circuit. The switching valve is coupled in particular to the pressure booster on the outlet side, so that when the pressure booster is actuated, the pressure generated in the brake circuit is held or increased in the brake circuit by the switching valve.
Further advantages and preferred features and combinations of features result in particular from the preceding description. The invention will be further explained below with the aid of the figures. To this end, it is shown that:
figure 1 braking system of a motor vehicle in a simplified illustration,
FIG. 2 is a drawing for explaining the brake force augmentation, an
Fig. 3 is a diagram for explaining an advantageous method for operating the brake system.
Fig. 1 shows a hydraulic brake system 1 in a simplified representation, which is used for a motor vehicle not shown in detail here. The brake system 1 is actuated by the driver of the motor vehicle via a brake pedal 2 when he wishes to start a braking process or to start decelerating the motor vehicle. The brake pedal 2 is coupled to the master brake cylinder 3. The brake pedal 2 can be coupled directly or indirectly via a joint drive to the master brake cylinder 3 for displacing a piston in the master brake cylinder for generating a hydraulic pressure.
The master brake cylinder 3 is hydraulically connected to a brake circuit 4. In principle, the brake system 1 can also have more than just one brake circuit 4. In the present case, the brake circuit 4 has a high-pressure switching valve 5 and a switching valve 6, which are connected in parallel to one another. The high-pressure switching valve 5 is embodied in a currentless, closed manner like the switching valve 6. Following the high-pressure switching valve 5 is a discharge valve 7, which is likewise embodied in a currentless, closed manner. After the switching valve 6 is an inlet valve 8, which is designed to be open without current. Both the outlet valve 7 and the inlet valve 8 are hydraulically connected to a wheel brake 9 of the brake system, which is assigned to one of the wheels of the motor vehicle. The wheel brake 9 is constructed in a conventional manner and has for this purpose in particular at least one brake piston which is mounted so as to be movable in a brake caliper and which can be actuated by means of hydraulic pressure from the brake circuit 4 in order to be pressed against a brake disk connected to the wheel in a rotationally fixed manner. The brake disk is clamped in particular between the brake linings of the wheel brake 9 which are arranged opposite one another, as a result of which friction between the brake linings and the brake disk is produced, which friction, depending on the hydraulic braking force, leads to a braking torque at the wheel. Furthermore, the wheel brakes 9 are assigned pressure sensors 10, which monitor the pressure of the hydraulic pressure in the wheel brakes. Likewise, a pressure sensor 11 is assigned to the master brake cylinder 3, which pressure sensor determines or detects the pressure of the master brake cylinder. Between the high-pressure switching valve 5 and the outlet valve 7, the suction side of a pressure booster 12 is also hydraulically connected, wherein the pressure booster 12 is connected on the pressure side between the switching valve 6 and the inlet valve 8 into the brake circuit 4. The pressure booster 12 is configured according to the present exemplary embodiment as an electrically motor-driven pump which can at any time boost the hydraulic pressure between the switching valve and the inlet valve 8 or the wheel brake 9 when it is actuated correspondingly by the control 13 of the brake system 1.
In the actuated/energized state, the high-pressure switching valve 5 is opened in the direction of the supercharger 12, wherein the outlet valve 7 is opened in the direction of the high-pressure switching valve 7 or the supercharger 12 in the actuated or actuated state. The switching valve 6 is opened in the actuated state in the direction of the master brake cylinder 3 and in the direction of the inlet valve 8. Likewise, the inlet valve 8 is opened in both directions, i.e. toward the switching valve 6 and toward the wheel brakes 9.
By means of the method described below, which is carried out by the control unit 13, the closed brake system 1 described here for electric and vacuum-free brake force boosting ensures a correlation between pedal force and vehicle deceleration. In this case, the basic components of an ESP system can be used. In particular, the valves 4, 6, 7, 8 and the pressure booster 12 are already part of ESP systems, so that the additional structural expenditure for carrying out the method is particularly low.
According to the present exemplary embodiment, a normally provided vacuum brake booster, which is connected between the brake pedal 2 and the master brake cylinder 3, is missing. Instead, the brake force boosting or support is automatically carried out by means of the pressure booster 12. Since the reaction force acting on the brake pedal 2 against the driver must be set over the pedal travel of the brake pedal 2 in order to generate the brake force augmentation by means of the pressure difference over the changeover valve 6, the driver always experiences a sensible correlation between the pedal force or reaction force and the brake force or vehicle deceleration.
The available brake fluid volume of the brake system 1 is preset in relation to the pedal travel of the brake pedal 2, so that an increased volume accommodation of the wheel brakes 9 results, for example, in a lower wheel pressure or brake pressure and thus in a lower vehicle deceleration. The pressure in the master brake cylinder and thus the reaction force acting against the brake pedal 2 or against the driver is set in accordance with the setpoint characteristic of the master brake cylinder 3. The correlation or reproducibility between the reaction force and the vehicle deceleration is therefore no longer present in the event of a volume fluctuation of, for example, more than 30%. Without further measures, the brake system 1 is therefore unable to simultaneously achieve a target setpoint pressure of the master brake cylinder, which leads to a corresponding reaction force, and a target setpoint pressure of the wheel brakes 9, which leads to a corresponding deceleration of the motor vehicle.
The correlation between the reaction force and the vehicle deceleration is thereby ensured by the method described below: when the additional or non-adjusted target quantity is not reached or exceeded, the target quantities are suitably adapted so that a correlated change of the two target quantities is reached, by using only one of the existing target quantities, preferably the setpoint pressure of the master brake cylinder or alternatively the setpoint pressure of the wheel brakes 9.
Furthermore, the brake pedal 2 is assigned a pedal travel sensor 14, which monitors the movement of the brake pedal 2. Depending on the detected pedal travel of the brake pedal 2, the controller 3 first calculates a target pressure for achieving a desired reaction force on the brake pedal 2 with the aid of the characteristic curve to be used and dependent on the respective motor vehicle. Using knowledge of the volume capacity of brake system 1, it is controlled by the pilot control of pressure booster 12 in order to displace into brake circuit 4 a volume that is not required for the pressure build-up in master brake cylinder 3. The pressure regulation, which is expediently superimposed on the volume when the pressure sensor 11 is used, is expediently adapted not only to the actuation of the pressure booster 12 but also to the actuation of the switching valve 6.
A target pressure characteristic curve, which shows the target pressure or the target pressure of the master brake cylinder in particular over the movement path of the brake pedal 2 in order to simulate a pedal force profile or a reaction force profile of a vacuum brake booster, is formed in such a way that the driver, despite the automated brake force support without the vacuum brake booster, still obtains a familiar driving sensation to him. The so-called jump effect (Jumpln-Effekt) is achieved by: the target pressure characteristic of the master brake cylinder 3 is maintained at 0 bar until the jump-in time without pressure.
Fig. 2 shows three diagrams for this purpose in a simplified representation, each of which shows a pedal force F as a reaction force against the driver in relation to a pedal travel sPPressure p in the master brake cylinder 33And the pressure p of the wheel brake 99. It can be seen here that the pedal force F is2Starting from 0 and at a pressure p3And p9Respectively, starting from 0 bar. In the brake pedal 2 to the position s1The reaction force F2 is only increased in the first movement section by the resilient means (Befederung) 15 assigned to the brake pedal 2, which resilient means are only outlined in fig. 1. In order to overcome the stroke s1The jump effect is effective, just like the pressure p by means of the wheel brake 99As can be seen, the pressure rises from this moment. As already mentioned, at this point in time, the pressure p in the master brake cylinder 33First at 0 bar. After passing over a subsequent travel point s2Pedal force F after a jump-in effect2And the pressure p in the master brake cylinder 33It rises.
Fig. 3 shows how the setpoint pressure characteristic curve for the master brake cylinder 3 shown in fig. 2 is determined for the method in order to be perceptible to the driver for the familiar braking force characteristic at the brake pedal 2, the actual values or the actual characteristic curve being shown by a solid line and the setpoint values or the setpoint characteristic curve being shown by a dashed line.
First, it is determined (A) at which pedal path s the jump effect occurs(s)1). Utilize to thisThe corresponding value calculates the stroke progression Δ s from the theoretical pressure characteristic curve. In order to correctly set the jump effect into the pressure of the master brake cylinder 3, the target pressure for the master brake cylinder is 0 bar up to the resulting stroke. Thus, the pressure p in the master cylinder 33Is shifted by the offset value deltas in order to compensate for the pre-filling of the brake system 1 or possibly for the already increased air gap.
In the hydraulic brake system 1, the stiffness of the brake circuit 4 can also be varied. This can be balanced by a stiffness coefficient f. The stiffness coefficient is determined (B) by: the setpoint pressure characteristic of the wheel brake 9 is shifted by the determined offset Δ s, so that the setpoint pressure and the actual pressure overlap at this point in time or travel point, at which the jump effect occurs, as shown in fig. 3. The stiffness factor f is determined by the quotient of the formation factors and is converted back in the bias transition. Subsequently, this stiffness factor is applied as a scaling factor or scaling factor (Skalierungsfaktor) to the theoretical pressure characteristic curve of the master brake cylinder 3, and from this (C) a current target pressure characteristic curve K for the master brake cylinder 3 is determined online3. This ensures that the reaction force at the brake pedal 2 and the wheel pressure or the vehicle deceleration are correlated as in conventional vehicles with vacuum brake force boosters, and that the stiffness of the brake system 1 and the changed volume requirement only lead to a change in the pedal travel during the desired deceleration.
The described method is advantageously used in the operating mode of a motor vehicle. However, it is also possible to store the average long-term value and to use it, if necessary, as a default, for example: in this case an online match cannot be applied. In the case of emergency braking or braking with high operating power, in which the delay time and the stagnation pressure may distort the determined result, for example, the evaluation is not possible. Even at extremely low temperatures, for example T < -30 ℃, calculations can be made due to the properties of the hydraulic medium used with increasing stagnation pressure effect and decreasing delivered power of the supercharger 12, so that the stored long-term values are then preferably used.
The method currently provides that the pressure of the master brake cylinder 3 is adjusted by adapting the wheel pressure or the pressure deviation of the wheel brakes 9; according to an alternative embodiment, it is provided that this is carried out in reverse, so that the adjustment of the wheel pressure or of the pressure in the wheel brake 9 is carried out by adapting the pressure deviation to the master brake cylinder 3.
Claims (10)
1. Method for operating a hydraulic brake system (1) of a motor vehicle, wherein the brake system (1) has a brake pedal (2), a master brake cylinder (3) coupled to the brake pedal (2), and at least one brake circuit (4) having at least one wheel brake (9), wherein a brake force boost is automatically set as a function of a brake pedal actuation, characterized in that the brake force boost is generated at least by means of an actuatable pressure booster (12) in the brake circuit (4) as a function of a brake pedal actuation on the one hand and as a function of a hydraulic pressure in the master brake cylinder (3) or in the wheel brake (9) on the other hand, wherein the pressure booster (12) is actuated as a function of a target pressure characteristic curve for the master brake cylinder (3) or for the wheel brake (9), wherein the target pressure characteristic curve is shifted by an offset value (Δ s) according to the idle stroke.
2. Method according to claim 1, characterized in that the brake pedal operation is detected by means of a pedal travel sensor (14).
3. Method according to claim 1 or 2, characterized in that a target pressure of the master brake cylinder (3) is determined as a function of the detected brake pedal actuation, wherein the target pressure is used as a target quantity in the actuation of the pressure booster.
4. A method according to claim 1 or 2, characterised in that a setpoint pressure for the wheel brakes (9) is determined as a function of a brake pedal operation, wherein the setpoint pressure is used as a target quantity in the actuation of the supercharger.
5. A method according to claim 1 or 2, characterised in that the supercharger (12) is operated as a function of the brake pedal operation in accordance with the desired volumetric capacity of the wheel brakes (9).
6. Method according to claim 1 or 2, characterized in that the target pressure characteristic curve is shifted by an offset value (Δ s) depending on the pre-filling and/or the air gap of the brake circuit (4).
7. Hydraulic brake system (1) for a motor vehicle, having a brake pedal (2), a master brake cylinder (3) coupled to the brake pedal (2), and having at least one brake circuit (4) having at least one wheel brake (9), wherein the brake circuit (4) is assigned at least one brake force intensifying apparatus, characterized in that the brake force intensifying apparatus has an actuatable pressure booster, which is actuated by an associated controller (13) which is designed to: operating the supercharger (12) according to the method according to any one of claims 1 to 6.
8. A brake system according to claim 7, characterized in that the master brake cylinder (3) and/or the wheel brakes (9) each have at least one hydraulic pressure sensor (10, 11).
9. A braking system according to claim 7 or 8, characterized in that the brake pedal (2) is provided with a pedal travel sensor (14).
10. A brake system according to claim 7 or 8, characterized in that the brake circuit (4) has at least one operable changeover valve (6) between the master brake cylinder (3) and the wheel brake (9).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102016209781.4A DE102016209781A1 (en) | 2016-06-03 | 2016-06-03 | Method for operating a hydraulic brake system, hydraulic brake system |
| DE102016209781.4 | 2016-06-03 | ||
| PCT/EP2017/058396 WO2017207147A1 (en) | 2016-06-03 | 2017-04-07 | Method for operating a hydraulic braking system, hydraulic braking system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109195843A CN109195843A (en) | 2019-01-11 |
| CN109195843B true CN109195843B (en) | 2021-10-22 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201780034438.3A Active CN109195843B (en) | 2016-06-03 | 2017-04-07 | Method for operating a hydraulic brake system, hydraulic brake system |
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| JP (1) | JP6886011B2 (en) |
| CN (1) | CN109195843B (en) |
| DE (1) | DE102016209781A1 (en) |
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| DE102018211051A1 (en) | 2018-07-04 | 2020-01-09 | Volkswagen Aktiengesellschaft | Method for controlling the braking force in an electro-hydraulic brake system of a motor vehicle |
| DE102021214646A1 (en) | 2021-12-17 | 2023-06-22 | Volkswagen Aktiengesellschaft | Braking method with reduced pedal travel, braking system and motor vehicle |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102991486A (en) * | 2011-09-12 | 2013-03-27 | 日立汽车系统株式会社 | Brake control apparatus |
| CN104395159A (en) * | 2012-08-23 | 2015-03-04 | 日立汽车系统株式会社 | Brake control device |
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|---|---|---|---|---|
| JPH0699797A (en) * | 1992-08-05 | 1994-04-12 | Nissan Motor Co Ltd | Brake control device |
| GB2321681B (en) * | 1997-02-03 | 2000-11-29 | Lucas Industries Ltd | Electronic braking system for vehicles |
| JP4244819B2 (en) * | 2004-02-18 | 2009-03-25 | 株式会社アドヴィックス | Braking device for vehicle |
| DE102011003144A1 (en) * | 2011-01-26 | 2012-07-26 | Robert Bosch Gmbh | Control device for a brake system of a vehicle, brake system and method for operating a brake system for a vehicle |
| DE102011075968A1 (en) * | 2011-05-17 | 2012-11-22 | Robert Bosch Gmbh | Control device for a brake system of a vehicle and method for operating a brake system of a vehicle |
| DE102011080431A1 (en) * | 2011-08-04 | 2013-02-07 | Robert Bosch Gmbh | Control device for a brake system of a vehicle, brake system for a vehicle and method for operating a brake system of a vehicle |
| DE102011087311A1 (en) * | 2011-11-29 | 2013-05-29 | Robert Bosch Gmbh | Control device for a brake system of a vehicle, brake system for a vehicle and method for operating a brake system of a vehicle |
| DE102011088942A1 (en) * | 2011-12-19 | 2013-06-20 | Robert Bosch Gmbh | Method for operating a recuperative braking system of a vehicle and control device for a recuperative braking system |
| DE102012209522A1 (en) * | 2012-06-06 | 2013-12-12 | Robert Bosch Gmbh | Method for operating a recuperative braking system of a vehicle and control device for a recuperative braking system of a vehicle |
| JP2014019266A (en) * | 2012-07-17 | 2014-02-03 | Hitachi Automotive Systems Ltd | Brake device for vehicle |
| KR101459448B1 (en) * | 2013-03-19 | 2014-11-07 | 현대자동차 주식회사 | Method for controlling braking of vehicle and system thereof |
| DE102013206324A1 (en) * | 2013-04-10 | 2014-10-16 | Robert Bosch Gmbh | Brake system for a vehicle and method for operating the brake system |
| CN105109472A (en) * | 2015-08-21 | 2015-12-02 | 奇瑞汽车股份有限公司 | Method and device for estimating hydraulic braking force of wheel cylinder |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102991486A (en) * | 2011-09-12 | 2013-03-27 | 日立汽车系统株式会社 | Brake control apparatus |
| CN104395159A (en) * | 2012-08-23 | 2015-03-04 | 日立汽车系统株式会社 | Brake control device |
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| Publication number | Publication date |
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| JP2019518660A (en) | 2019-07-04 |
| WO2017207147A1 (en) | 2017-12-07 |
| DE102016209781A1 (en) | 2017-12-07 |
| CN109195843A (en) | 2019-01-11 |
| JP6886011B2 (en) | 2021-06-16 |
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