Method for activating mechanism in brake booster in braking system, and braking system

Abstract

To provide a method for activating a mechanism in a brake booster in a braking system.SOLUTION: The method includes the steps of: detecting whether or not there is no driver braking request after a previous braking operation by a brake booster; detecting, by a controller, a malfunction of the brake booster; and if the driver braking request has ended, or if there is no longer a driver braking request, increasing, by a pressure regulator, a predetermined minimum pressure in a brake master cylinder system, so as to return, by this mechanism, a brake master cylinder to a neutral position with reduced braking action or a neutral position with no braking action in one brake element, and in this case, activating, by the controller, the pressure regulator.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for activating a mechanism in a brake booster of a braking system and to a braking system. [Background technology]

[0002] When a brake booster is used, the return spring can displace the brake master cylinder back to the neutral position after a braking process, thereby reducing the brake pressure again. The return spring can be mounted on the housing of the brake master cylinder and limit the path of movement of the brake master cylinder in the direction of increasing the brake pressure. In other words, the brake cylinder piston can only move toward the brake master cylinder mainly until the return spring is compressed. Therefore, the return spring can be of a limited length and can impinge on a sealing sphere in the low-pressure hole of the pot / cylinder housing.

[0003] Usually, the return of the transmission in the brake booster can be ensured by a single return spring for mechanical backup, where the so-called backup can be related to a motor failure, for example in the event of a power failure of the motor, in which case the return spring can take over the return movement of the brake master cylinder and the return movement of the transmission unit that would otherwise be moved by the motor for the return, thereby releasing the brake application position of the brake master cylinder.

[0004] It is also known to use electromechanical pressure controllers in braking systems. An electronic stability program (ESP) can similarly use valves, circular reservoirs, and pumps to increase or decrease pressure at each wheel. A primary pressure controller can be located upstream of the ESP and act on the pistons of a tandem brake master cylinder (TMC) to increase pressure in response to braking demand, which can also be obtained via an external command (by-wire). In the case of pressure increase, the pressure controller can be similarly controlled and operated, but in this case, the pressure controller can be additionally pushed back (to the brake neutral position) by the brake pressure and a return spring provided for it. Returning the leak hole in the TMC until it opens can be necessary whenever there is no braking demand.

[0005] Patent document 1 describes a braking device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] German Patent Application Publication No. 102011112957 Summary of the Invention

[0007] The present invention provides a method for activating a mechanism in a brake booster of a braking system according to claim 1 and a braking system according to claim 9.

[0008] Advantageous further configurations are the subject of the dependent claims.

[0009] The basic idea of ​​the present invention is to provide a method for activating a mechanism in a brake booster and a brake system, in which the return of the brake booster mechanism to a neutral braking position can be achieved without a return spring.

[0010] According to the present invention, a method for activating a mechanism in a brake booster of a brake system includes detecting, using a control device in a vehicle, whether the driver's braking request has ended after a previous braking process by the brake booster or whether there is no driver's braking request in the brake booster after a previous braking process by the brake booster, detecting a malfunction of the brake booster by the control device, and, if the driver's braking request has ended or is no longer present, increasing a predetermined minimum pressure in the brake master cylinder device by a pressure regulator, thereby returning the mechanism, and thereby the brake master cylinder, to a neutral position with reduced braking effect or no braking effect in one brake element, wherein the pressure regulator is activated by the control device.

[0011] The pressure regulator may be included in the brake booster, may be external thereto, may be a separate device, or the driving stability system (ESP) may take on the role of pressure regulator (in this case, if there are multiple pressure regulators, the ESP may be referred to as a further pressure regulator).

[0012] Activation may be such a position adjustment or movement of a mechanism that activates or deactivates the braking action in a friction brake, for example, returning the brake master cylinder of a brake booster from a braking position in which the friction brake is active to a neutral position.

[0013] The control device may be separate from the brake booster and may be, for example, a control device for an electronic stability program (ESP).

[0014] Advantageously, the brake booster mechanism can be reset without the use of a return spring.

[0015] A malfunction can be a complete or partial failure of the function of the brake booster, for example a complete or partial failure of the electric motor that can effect recovery.

[0016] The pressure regulator may be connected to or include a pump and reservoir for hydraulic fluid, and may provide a specific fluid volume to increase or decrease a specific pressure in the brake master cylinder, which in turn provides a pressure that resists movement for braking action in the brake master cylinder.

[0017] The neutral position may correspond to a range for the brake master cylinder position in which the braking force on the brakes may be reduced or non-existent. That is, if the brakes are to be released, the brake master cylinder can be displaced from the brake position to the neutral position by a return spring. The brake master cylinder may be connected to another spring in the cylinder housing. The return spring may have a radius smaller than the radius of the cylinder housing, in which case the cylinder housing itself may have cylindrical symmetry relative to the main direction of extension. In this case, the storage device may be a volume receiver of the brake cylinder, which allows a temporary slight increase in wheel brake pressure if a more suitable storage device is not available.

[0018] In this method, the validity of information (data relating to the state and position of the brake mechanism) accessible to the driving stability system (ESP) in the fallback (state for resetting the brake mechanism) is checked for the reset function of the brake booster to obtain a validity check that triggers the reset by the pressure regulator.

[0019] According to an advantageous embodiment of the method, the malfunction of the brake booster concerns the return of said mechanism to a neutral position by the brake booster.

[0020] When such malfunctions occur, the ability to reset the mechanism may be reduced or even eliminated.

[0021] According to an advantageous embodiment of the method, the detection of the driver's braking request can be performed by the brake booster, and the transmission of information to the control device regarding the presence or termination of the driver's braking request is performed by the brake booster.

[0022] It may be even more advantageous if the brake booster itself then communicates whether the driver's braking request has ended and whether a return should be made.

[0023] According to an advantageous embodiment of the method, the detection of the driver's braking request by the brake booster is exceptional.

[0024] In the event of a complete failure, recovery can still be effected by corresponding pressure increase of the pressure regulator, which may advantageously include a reservoir for the hydraulic fluid and a pump for the driving stability system or other systems.

[0025] According to an advantageous embodiment of the method, the pressure in the brake master cylinder is detected by the control device and compared with a predetermined cylinder pressure, and if the pressure in the brake master cylinder is greater than or equal to the predetermined cylinder pressure and there is no driver braking request, the previous braking process and the need for resumption are recognized.

[0026] In this case, high internal pressure may remain in the cylinder housing, which should be advantageously released by the return. The residual pressure in the cylinder initially pushes the piston back by itself until the hydraulic force on the piston and the frictional forces in the mechanism and the associated transmission are counterbalanced. At this point, a volume flow in the cylinder can be maintained, for example by a pump in the ESP or pressure controller, to further push the mechanism and piston back toward the neutral position. This allows a return force in the piston that is greater than the frictional force (pressure in the direction of braking action).

[0027] According to an advantageous embodiment of the method, the driver recognizes that there is a braking desire and, by means of the pressure regulator or by means of a further pressure regulator, pushes the mechanism into a braking position for the braking process.

[0028] Advantageously, braking can also be effected by a pressure regulator. The pressure boost of the ESP system can be induced by a valve at either the wheel or the TMC, and can then be induced to only one side of the TMC piston.

[0029] According to an advantageous embodiment of the method, the control device is a control device of a vehicle stability system.

[0030] According to an advantageous embodiment of the method, the control device infers that there is a driver braking desire based on information about the vehicle being stopped and / or based on the pedal position of the accelerator pedal of the vehicle and / or based on the position of the brake pedal and / or based on detection of the speed and / or speed gradient of the vehicle.

[0031] The above data and parameters can be detected by sensor devices in the vehicle.

[0032] The function of recovery by the pressure regulator, preferably by the driving stability system (ESP), may be necessary if the brake booster fails and cannot be recovered by its own electric motor. For this reason, the ESP, and in particular its control device, can monitor in the vehicle whether the brake booster is always available.

[0033] If the brake booster is still able to transmit a valid driver braking request, the ESP can use this to decide whether or not it is necessary to push back the mechanism when the driver braking request ends.

[0034] If the brake booster is unable to provide reliable information regarding the driver's braking desire, several signals may be available for the ESP to process in order to perform a plausibility check as to whether reversion is necessary.

[0035] These signals that the control device can obtain to activate the reversion function, in particular to operate the pressure regulator and perform reversion, may be information regarding the presence of a driver braking request, measured brake master cylinder pressure, an active brake light switch (which infers the braking request), accelerator pedal position from which it can be read whether to accelerate (i.e. not decelerate) or brake, or vehicle stop information.

[0036] The reactivation function can be activated if the brake master cylinder pressure is greater than zero or greater than a predetermined minimum value, if the brake booster does not transmit a driver braking request, and / or, as another option, if the driver braking request information measured directly in the ESP does not indicate a driver braking request (e.g., via an external brake light switch), if the accelerator pedal position is greater than 0%, and / or if a stall is detected (the ESP can pre-store a certain volume in the reservoir and directly start the function when the accelerator pedal position is greater than 0%). Such information and signals can trigger the reactivation function, especially in the event of a malfunction of the driver braking request function. The ESP preferably receives the accelerator pedal position as a percentage between 0% and 100%. If the ESP displays an accelerator pedal position greater than 0%, the ESP can interpret this as meaning that the driver does not want to brake. If the driver wishes to brake, the ESP has the task of boosting wheel pressure as quickly as possible as a recovery measure in the event of failure of the primary pressure controller (for braking action of the brake pedal or the brake booster mechanism). Only when the ESP knows that the driver does not wish to brake can the recovery function be activated. The ESP has a small reservoir that can be filled. The ESP's objective is to keep the reservoir as empty as possible during normal operation, so that in the event of ABS braking the ESP has an empty reservoir from which it can release wheel pressure.

[0037] Thus, if the primary actuator fails, the ESP can act as a backup controller to boost wheel pressure according to the driver's braking request. The reservoir design can be modified to use a partially filled reservoir as the target fill value. After the driver's braking has ended, the primary actuator (brake pedal action and / or brake booster activation) may need to be fully restored, which may require additional volume. If the ESP already has this volume thanks to clever reservoir management, there is no need to draw it from the reservoir beforehand.

[0038] Furthermore, it may be desirable to return the brake booster mechanism to its neutral position using a return function other than driver braking (in this case, the return pressure in the brake master cylinder can be increased via a pressure regulator). If the ESP measures the driver's braking request externally and directly, it can use the ESP to detect the driver's braking request and to utilize information regarding the presence or absence of a driver's braking request. If the accelerator pedal is depressed, it may be possible to infer from this that the driver intends to accelerate but not brake. Depending on the vehicle, for example, speed information detected by the sensor device can be used to increase wheel pressure when the pedal is depressed while stationary, or to directly utilize additional volume for return during startup by pre-filling the reservoir for the pressure regulator. Here, in the event of a primary actuator failure, there is a driver's braking request. When the vehicle is stationary, there is no effect on vehicle dynamics, but if the driver wants to brake, for example, at 10 bar, the ESP will increase the pressure in the wheels by 20 bar to store more volume in the wheels. In this way, the wheels are automatically used as a reservoir to ensure there is sufficient volume to push back the failed primary actuator afterwards.

[0039] By applying the return via a pressure regulator, the length of the structure can be reduced by eliminating or miniaturizing the return spring. Further, cost savings can be achieved by saving on the spring.

[0040] According to the present invention, the braking system comprises a brake booster and a control device, wherein the brake booster is connectable to the control device, or includes the control device and is connectable to a pressure regulator, or includes the pressure regulator, wherein the control device is arranged to detect whether the driver's braking request has ended after the previous braking process by the brake booster, or whether there is no driver's braking request in the brake booster after the previous braking process by the brake booster, and wherein the control device is arranged to detect a malfunction of the brake booster if the driver's braking request has ended or if there is no driver's braking request any more, and to increase a predetermined minimum pressure in the brake master cylinder device by the pressure regulator, thereby returning the mechanism, and thereby the brake master cylinder of the brake booster, to a neutral position with reduced braking effect or no braking effect in one brake element, and the pressure regulator is operable by the control device.

[0041] According to an advantageous embodiment of the brake system, the control device comprises a control device for a vehicle stability system.

[0042] The braking system may also be characterized by the features and advantages discussed in connection with the present method, or vice versa.

[0043] Further features and advantages of embodiments of the present invention will become apparent from the following description, which refers to the accompanying drawings.

[0044] The invention will now be explained in more detail using embodiments illustrated in the schematic diagrams of the drawings. [Brief explanation of the drawings]

[0045] [Figure 1] 1 is a schematic diagram of a braking system according to one embodiment of the present invention. [Figure 2] 2 is a block diagram of method steps of a method for activating a mechanism in a brake booster in a braking system according to one embodiment of the present invention; [Figure 3] FIG. 6 is a block diagram of method steps of a method for activating a mechanism in a brake booster in a braking system according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0046] In the drawings, like reference numbers indicate identical or functionally identical elements.

[0047] FIG. 1 is a schematic diagram of a braking system according to one embodiment of the present invention.

[0048] A brake system 1 is shown which comprises a brake booster 10 and a control device SE, in which the brake booster 10 can be connected to or includes the control device SE and can be connected to or includes a pressure regulator (not shown), in which the control device SE is arranged to detect whether the driver's braking request has ended after the previous braking process by the brake booster 10 or whether there is no driver's braking request in the brake booster 10 after the previous braking process by the brake booster 10, and the control device SE is further arranged to detect a malfunction of the brake booster 10 if the driver's braking request has ended or if there is no driver's braking request any more, and to increase a predetermined minimum pressure in the brake master cylinder device HZE by means of the pressure regulator, thereby returning the mechanism and thereby the brake master cylinder of the brake booster 10 to a neutral position with reduced braking effect in one brake element or to a neutral position with no braking effect, in which case the pressure regulator can be operated by the control device SE. The mechanism can be operated by means of an electric motor EM, which may, however, be deactivated in the event of a brake booster malfunction.

[0049] FIG. 2 is a block diagram of method steps of a method for activating a mechanism in a brake booster in a braking system according to one embodiment of the present invention.

[0050] If in a first step A1 it is determined that the brake booster malfunctions, but that the driver's braking request detection and the vehicle and brake booster network are still functioning (j), then in a further step A2 the driving stability system (ESP) can measure the pressure in the brake master cylinder and determine whether it is greater than zero. In the rest position of the pressure regulator / primary actuator / TMC, the TMC's leakage hole should be open, which connects the TMC and the brake circuit to a reservoir at atmospheric pressure, so that said pressure can advantageously be zero (atmospheric pressure) in the rest position. Therefore, the brake system can be pressureless in the target state.

[0051] The control device can detect the pressure in the brake master cylinder and compare it with a predetermined cylinder pressure (as a reference value), in which case if the pressure in the brake master cylinder is greater than or equal to the predetermined cylinder pressure and there is no driver braking request, a previous braking process and the need for resumption are recognized.

[0052] If this is not the case (n), step A2 can be repeated, preferably multiple times. However, if this is the case (pressure is greater than zero) (j), the brake booster can transmit the driver's braking request via the network in a further step A3, preferably to the driving stability system (ESP). If the transmission is successful (j), the ESP can initiate HBC (Hydraulic Boost Failure Compensation) in a further step A5. Otherwise (n), the ESP initiates the recovery function (A4). If the pressure in the TMC / brake circuit measured within the ESP is already zero, this means that the pressure regulator / primary actuator did not trap pressure at the moment of failure. Therefore, the recovery function can be omitted. HBC is the name of a driver assistance function in the event of a primary pressure controller failure. If the ESP receives a driver braking request, even if pressure remains trapped after the primary actuator failure, the driver's braking request can have higher priority than the primary actuator recovery. In this case, the goal may be to first have the ESP realize the driver's braking request, and in a second step, if there is no driver's braking request, to restore the primary actuator.

[0053] FIG. 3 is a block diagram of method steps of a method for activating a mechanism in a brake booster in a braking system according to another embodiment of the present invention.

[0054] If the first step B1 determines that the brake booster has malfunctioned (j), i.e., if it determines that the brake booster has not initiated a recovery and the driver's braking request has not been transmitted via the vehicle's network, then in a further step B2, the driving stability system (ESP) can measure the pressure in the brake master cylinder to determine whether it is greater than zero. If this is not the case (n), step B2 can be repeated, preferably multiple times. However, if this is the case (pressure greater than zero) (j), then the brake booster can determine in a further step B3 whether there is a driver's braking request, preferably if this is detected by a signal plausibility check in the ESP by matching certain signals and / or parameters from the vehicle, the driving stability system, and / or the brake booster. If a braking request is detected (j), then in a further step B5, the ESP can start a hydraulic boost failure compensation (HBC). Otherwise (n), the ESP initiates the recovery function (B4). If the pressure remains trapped after the primary actuator failure, but the ESP receives a driver braking request, the driver's braking request has a higher priority than the recovery of the primary actuator. The goal here can be to have the ESP first realize the driver's braking request and, in a second step, recover the primary actuator if there is no driver braking request. If the pressure in the TMC / brake circuit measured in the ESP is already zero, this means that the pressure controller / primary actuator did not trap pressure at the moment of failure. Therefore, the recovery function activation can be omitted.

[0055] Although the present invention has been fully described above with reference to preferred embodiments, it is not limited thereto and can be modified in many ways and aspects. [Explanation of symbols]

[0056] 1. Brake system 10 Brake booster A1: Steps to check whether the brake booster is malfunctioning, but the driver's braking request detection and the vehicle and brake booster network are still functioning. A2: Measure the pressure in the brake master cylinder to determine if it is greater than zero. A3 Step of transmitting driver's braking request to the driving stability system (ESP) A4 Steps to start the recovery function A5 Steps to start HBC B1 Step to determine if the brake booster is malfunctioning B2: Step for detecting whether the pressure in the brake master cylinder is greater than zero B3 Step to check if the driver has requested braking B4 Step to start the return function Steps to start B5 HBC F vehicle HZE brake master cylinder device SE control device

Claims

1. In a method for activating a mechanism within a brake booster (10) in a brake system (1), - Step (S1) of detecting, using a control device (SE) in the vehicle (F), whether the driver's braking request has ended since the previous braking process by the brake booster (10), or whether there is no driver braking request to the brake booster (10) since the previous braking process by the brake booster (10), - Step (S2) of detecting a malfunction in the brake booster (10) using the control device (SE), - Step (S3) of increasing the predetermined minimum pressure in the brake master cylinder device (HZE) by a pressure regulator once the driver braking request has ended or there are no more driver braking requests, thereby returning the mechanism and the brake master cylinder by this mechanism to a neutral position with reduced braking force in one brake element or a neutral position without braking force, in which case the pressure regulator is operated by the control device (SE), A method that includes this.

2. The method according to claim 1, wherein the malfunction of the brake booster (10) is related to the return of the mechanism to the neutral position by the brake booster (10).

3. The method according to claim 2, wherein the detection of the driver's braking request is functionally possible by the brake booster (10), and the transmission of information regarding whether or not a driver's braking request has been made to the control device (SE) is effective by the brake booster (10).

4. The method according to claim 2, wherein the detection of the driver's braking request by the brake booster (10) is exceptional.

5. The method according to any one of claims 1 to 4, wherein the control device (SE) detects the pressure in the brake master cylinder and compares it with a predetermined cylinder pressure, and if the pressure in the brake master cylinder is greater than or equal to the predetermined cylinder pressure, and there is no request for braking from the driver, the previous braking process and the need for return are recognized.

6. The method according to any one of claims 1 to 4, wherein, upon recognizing a driver request for braking, the mechanism is pushed to the brake position for the braking process by the pressure regulator or by a further pressure regulator.

7. The method according to any one of claims 1 to 4, wherein the control device is a control device for a vehicle stability system.

8. The method according to any one of claims 1 to 4, wherein the control device estimates that there is a driver braking request based on information regarding the stopping of the vehicle, and / or the pedal position of the vehicle's accelerator pedal, and / or the position of the brake pedal, and / or the detection of the vehicle's speed and / or speed gradient.

9. In a brake system (1) comprising a brake booster (10) and a control device (SE), the brake booster (10) is connectable to the control device (SE), or includes the control device (SE) and is connectable to a pressure regulator, or includes a pressure regulator, and the control device (SE) is installed to detect whether the driver's braking request has ended after the previous braking process by the brake booster (10), or whether there is no driver braking request to the brake booster (10) after the previous braking process by the brake booster (10), and further the control device (SE) is installed to detect whether the driver's braking request has ended after the previous braking process by the brake booster (10), and further the control device (SE) is installed to detect whether the driver's braking request has ended A brake system (1) is installed to detect a malfunction of the brake booster (10) if the brake request has ended or if there are no more driver brake requests, and to increase a predetermined minimum pressure in the brake master cylinder device (HZE) using the pressure regulator, thereby returning the mechanism, and by this mechanism, the brake master cylinder of the brake booster (10) to a neutral position with reduced braking force or a neutral position without braking force in one brake element, and the pressure regulator is operable by the control device (SE).

10. The brake system (1) according to claim 9, wherein the control device (SE) includes a control device (SE) for a vehicle stability system.

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