JP2020037391A - Method for actuating brake system and brake system - Google Patents

Abstract

To provide a method for actuating a brake system for an automobile.SOLUTION: The method for actuating a brake system includes steps of: calculating a first brake liquid volume (V) moved from a brake master cylinder (10) into the brake system (1) by an operation of a brake pedal (2) by a driver in an automobile; calculating second brake liquid volumes (V) in wheel brake cylinders (26, 28, 30 and 31) of the brake system (1); and calculating a third brake liquid volume (V) in at least one storage chamber (20 or 22) of the brake system (1) by using the calculated first brake liquid volume (V) and the calculated second brake liquid volumes (V).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for operating an automotive brake system. Furthermore, the invention relates to a brake system for a motor vehicle.

  Conventional methods for operating the brake system include evaluating or determining a brake fluid volume in one of the reservoirs of the brake system.

  In electrically actuated and hybrid vehicle braking systems, braking force is provided by both regenerative braking torque generated by the electric machine and hydraulic braking torque generated by the braking system.

  In this case, in various driving situations, in order to obtain a stable braking force even in the case of a regenerative operation of the vehicle, the regenerative brake torque and the brake torque generated by the hydraulic pressure can be coordinated.

  Within the range of purely regenerative braking, the brake fluid volume is moved into at least one reservoir of the brake system in order to prevent the occurrence of hydraulic braking torque. Thereafter, at a later point in time, the pump may be used to reduce the regenerative braking torque and to convey the hydraulic braking torque to move the brake fluid volume in the at least one storage chamber back into the braking system. Operated. To avoid excessive movement of the brake fluid volume into the at least one storage chamber, it is necessary to evaluate or calculate the brake fluid volume in the at least one storage chamber.

  In a conventional ESP system, the volume flow flowing through a valve into at least one storage chamber is calculated according to Bernoulli's principle. However, in the case of brake torque coordination, the rear exhaust valve of the brake system is continuously open, so that the pressure between the rear exhaust valve and the reservoir is directly compensated, which results in the Bernoulli equation The pressure difference is not high enough to calculate the volume flow on the basis.

  Even if a sufficiently high pressure difference is detected by dynamic action, the pressure estimation based on this is inaccurate, so that it is not possible to calculate the volume flow with the required accuracy.

  Patent Literature 1 discloses an automotive brake system including a brake master cylinder, a first brake circuit including a first storage chamber, a first wheel brake cylinder, and a second wheel brake cylinder. In this case, the first wheel brake cylinder is hydraulically connected to the first storage chamber via a first wheel discharge valve, and the second wheel brake cylinder is connected to the second wheel discharge valve via a second wheel discharge valve. Is hydraulically coupled to the storage chamber.

DE 10 2016 208 529 A1

  The present invention provides a method for operating a vehicle brake system. The method includes calculating a first brake fluid volume moved from a brake master cylinder into the brake system by operating a brake pedal by a vehicle driver. The method further includes calculating a second brake fluid volume within the wheel brake cylinder of the brake system.

  The method further includes calculating a third brake fluid volume in at least one storage chamber of the brake system using the calculated first brake fluid volume and the calculated second brake fluid volume. Contains.

  The present invention further calculates a first brake fluid volume moved from the brake master cylinder into the brake system by operating a brake pedal by a driver of the vehicle, and calculates a second brake fluid in a wheel brake cylinder of the brake system. Calculating a third brake fluid volume in the at least one storage chamber of the brake system using the calculated first brake fluid volume and the calculated second brake fluid volume; Provided is a vehicle brake system including an installed arithmetic unit.

  The idea of the present invention is that the first brake fluid volume moved from the brake master cylinder into the brake system when the driver operates the brake pedal, and the second brake fluid volume in the wheel brake cylinder of the brake system. Use to calculate a third brake fluid volume in at least one reservoir of the brake system, thereby enabling a more accurate calculation of a third brake fluid volume in at least one reservoir of the brake system. It is to do.

  This results from the fact that when the driver operates the brake pedal, the compensating connection of the brake master cylinder is closed, thus making the brake system a closed system. As a result, the volume of the brake fluid moved from the brake master cylinder into the brake system by operating the brake pedal is present either in the wheel brake cylinder of the brake system or in at least one storage chamber. Thus, an accurate calculation of the volume of the brake fluid in at least one storage compartment of the brake system can be made taking into account the aforementioned components.

  Advantageous embodiments and further configurations are evident from the dependent claims and the description with reference to the figures.

  According to an advantageous further configuration, calculating the first volume of brake fluid moved from the brake master cylinder into the brake system by operating the brake pedal by the driver of the motor vehicle comprises determining the diameter of the brake master cylinder, the pedal As implemented using the displacement distance of the output rod of the brake system coupled to the brake pedal, detected by the stroke sensor, and the displacement distance of the output rod for closing the compensating connection of the brake master cylinder. It is configured. In this way, the displacement distance detected by the pedal stroke sensor can be used to advantageously enable an accurate calculation of the volume of brake fluid transferred from the brake master cylinder into the brake system.

  According to another advantageous further configuration, calculating the second brake fluid volume in the wheel brake cylinder of the brake system uses the brake fluid pressure in the wheel brake cylinder and the stiffness of the brake system. It is configured to be implemented. In this way, an accurate calculation of the brake fluid volume in the wheel brake cylinder can be advantageously provided.

  According to another advantageous further development, the second brake fluid volume in the wheel brake cylinder of the brake system is divided into the brake fluid volume in the wheel brake cylinder of the front axle of the motor vehicle and the brake fluid volume in the wheel brake cylinder of the rear axle. It is configured to calculate by adding the brake fluid volume. In this way, the use of data on the brake fluid volume of all wheel brake cylinders allows for an accurate determination of the brake fluid volume in the wheel brake cylinders.

  According to a further advantageous further development, the brake fluid pressure in the wheel brake cylinder of the front axle is measured by a pressure sensor in the region of the brake master cylinder, the brake fluid pressure in the wheel brake cylinder of the rear axle being determined. It corresponds to the brake fluid pressure in at least one storage chamber of the brake system and is configured such that the brake fluid pressure in the rear axle wheel brake cylinder is between 1.2 bar and 1.6 bar. .

  Based on the measurement of the brake fluid pressure at the front axle by the pressure sensor and the fact that the brake fluid pressure in the region of the rear axle corresponds to the brake fluid pressure in at least one storage chamber, the brake in the wheel brake cylinder is An exact specification of the hydraulic pressure can be advantageously provided.

  According to another advantageous further development, the calculation of the third brake fluid volume in the at least one reservoir of the brake system is performed by calculating the difference between the first brake fluid volume and the second brake fluid volume. It is constituted so that it may be implemented. Therefore, since the driver can operate the brake pedal to accurately identify the volume of the brake fluid moved from the brake master cylinder into the brake system and the volume of the brake fluid in the wheel brake cylinder, at least one storage An accurate calculation of the volume of the brake fluid in the room can be scheduled in an advantageous manner.

  According to a further advantageous further refinement, the regeneration generated by the electric machine when the calculated third brake fluid volume in the at least one storage compartment of the brake system is above a preset threshold value. The torque coordination between the brake torque and the brake torque generated by the hydraulic pressure by the brake system is terminated. In this way, an overfill of at least one reservoir of the brake system can be prevented in an advantageous manner.

  According to a further advantageous further development, the at least one reservoir is emptied if the calculated third brake fluid volume in the at least one reservoir of the brake system is above a preset threshold value. The pump is configured to operate the By operating the pump, the storage chamber can be emptied in an advantageous manner when it is determined that the threshold value has been exceeded.

  According to another advantageous further development, when calculating the second brake fluid volume in the wheel brake cylinder of the brake system, the brake fluid volume in the first front wheel brake cylinder and the second front brake fluid volume are calculated. The brake fluid volume in the rear wheel brake cylinder, the brake fluid volume in the first rear wheel brake cylinder, and the brake fluid volume in the second rear wheel brake cylinder are calculated. In this way, the total volume of the brake fluid in all wheel brake cylinders of the brake system of the motor vehicle can be taken into account in an advantageous manner.

  The configurations described above and further configurations can be arbitrarily combined with one another.

  Other possible configurations, further configurations and implementations of the present invention also include combinations of the above-described components of the present invention or described with reference to the embodiments of the present invention, which have not been explicitly mentioned.

  The accompanying drawings are for a better understanding of the embodiments of the present invention. These drawings illustrate embodiments and are used in connection with the description which illustrates the principles and concepts of the present invention.

Other embodiments and many of the aforementioned advantages will be apparent in view of the drawings. The elements shown in the figures are not necessarily shown to scale with respect to one another.
1 is a hydraulic circuit diagram of a vehicle brake system according to an advantageous embodiment of the present invention; 4 is a flowchart of a method for operating a vehicle brake system according to the advantageous embodiment of the present invention.

  In the figures of the drawings, the same reference numbers refer to the same or functionally identical elements, components or components, unless stated to the contrary.

  FIG. 1 is a hydraulic circuit diagram of a vehicle brake system according to an advantageous embodiment of the present invention.

  The automotive brake system 1 includes a brake master cylinder 10, a first brake circuit 12 coupled to the brake master cylinder 10, and a second brake circuit 14 coupled to the brake master cylinder 10. ing.

The brake system 1 further includes an arithmetic unit 6 installed for calculating a _first brake fluid volume V1 moved from the brake master cylinder 10 into the brake system 1 by operating the brake pedal 2 by the driver of the vehicle. (See Equation (1)).

  D is the diameter of the brake master cylinder 10, s (output rod) is the displacement distance of the output rod 3 of the brake system 1 connected to the brake pedal 2, and s (compensation connection closed) is the compensation connection 4 of the brake master cylinder. Is the displacement distance of the output rod 3 for closing the output rod.

Further, the arithmetic unit 6 is provided for calculating the _second brake fluid volume V2 in the wheel brake cylinders 26, 28, 30, 31 of the brake system 1 (see Equation (2)).

  c (VA, Model) is the stiffness of the brake system in the region of the front axle, c (HA, Model) is the stiffness of the brake system in the region of the rear axle, dP is the pressure difference, and dt is the time interval.

Further, the arithmetic unit 6, first using the second and the brake fluid volume V ₂ and the calculated brake fluid volume V ₁ calculated, in at least one storage chamber 20, 22 of the brake system 1 first 3 are installed in order to calculate the brake fluid volume V ₃ (see equation (3)).

V ₃ = V ₁ −V ₂ Equation (3)

  Furthermore, the brake system 1 has a plurality of switchable valves 32, 33, 34, 35, 36, 37, 38, 39, 40, 41. These valves are known to those skilled in the art as to their location and functionality and will not be described in detail here.

  FIG. 2 is a flowchart of a method for operating a vehicle brake system according to an advantageous embodiment of the present invention.

In step S1, the first calculation of the brake fluid volume V ₁ that has moved from the brake master cylinder 10 to the brake system 1 by the vehicle driver operates the brake pedal 2. In step S2, it performs the second calculation of the brake fluid volume _{V 2} which is in the wheel brake cylinders 26,28,30,31 of the brake system 1.

In step S3, the first using a second brake fluid volume V ₂ and the calculated brake fluid volume V _1, a third brake in at least one storage chamber 20, 22 of the brake system 1 calculated to calculate the liquid product _{V 3.}

First calculation S1 of the brake fluid volume V ₁ that has moved from the brake master cylinder 10 to the brake system 1 by the vehicle driver operates the brake pedal 2, the diameter D of the brake master cylinder 10, a pedal stroke sensor 13 Using the displacement distance of the output rod 3 of the brake system 1 coupled to the brake pedal 2 and the displacement distance of the output rod 3 for closing the compensating connection 4 of the brake master cylinder, as detected by You.

Further, the brake fluid pressure at the second calculation S2 of the brake fluid volume _{V 2} which is in the wheel brake cylinders 26,28,30,31 of the brake system 1 is within the wheel brake cylinders 26,28,30,31, This is performed using the rigidity of the brake system 1.

Further, the second brake fluid volume _{V 2} in the wheel brake cylinder 26,28,30,31 of the brake system 1 comprises a brake fluid volume in the wheel brake cylinders 30, 31 of the front axle 24 of the motor vehicle, the rear axle It is calculated by adding the 25 brake fluid volumes in the wheel brake cylinders 26 and 28. The brake fluid pressure in the wheel brake cylinders 30, 31 of the front axle 24 is measured by a pressure sensor 5, preferably in the region of the brake master cylinder 10. Alternatively, the pressure sensor 5 may be located elsewhere in the brake system 1.

  The brake fluid pressure in the wheel brake cylinders 26, 28 of the rear axle 25 corresponds to the brake fluid pressure in at least one storage chamber 20, 22 of the brake system 1. The brake fluid pressure in the wheel brake cylinders 26, 28 of the rear axle 25 is preferably between 1.2 bar and 1.6 bar.

Third calculating S3 of the brake fluid volume V ₃ in at least one storage chamber 20, 22 of the brake system 1 is preferably the difference between the first brake fluid volume V ₁ and the second brake fluid volume V ₂ Is calculated.

The torque coordination between the regenerative braking torque generated by the electric machine (not shown) and the hydraulically generated braking torque by the brake system 1 is calculated by calculating at least one reservoir 20 of the brake system 1. , the third brake fluid volume V ₃ within 22 to terminate if it exceeds a preset threshold value. Calculated, the third brake fluid volume V ₃ in at least one storage chamber 20, 22 of the brake system 1, if it exceeds a preset threshold value, preferably, at least one storage chamber 20, 22 The pumps 42 and 43 for emptying are operated.

In the case of calculation S2 of the _second brake fluid volume V2 in the wheel brake cylinders 26, 28, 30, 31 of the brake system 1, the brake fluid volume in the first front wheel brake cylinder 30 and the second The brake fluid volume in the front wheel brake cylinder 31, the brake fluid volume in the first rear wheel brake cylinder 26, and the brake fluid volume in the second rear wheel brake cylinder 28 are calculated.

  Although the present invention has been described above based on advantageous embodiments, the present invention is not limited to this, and can be variously modified. In particular, the present invention can be variously modified or changed without departing from the gist of the invention.

  For example, the size, performance or configuration of the brake master cylinder, wheel brake cylinder, storage chamber may be adapted to the respective structural, organizational and / or control technical requirements.

DESCRIPTION OF SYMBOLS 1 Brake system 2 Brake pedal 3 Output rod 4 Compensation connection part 5 Pressure sensor 6 Computing device 10 Brake master cylinder 13 Pedal stroke sensor 20, 22 Storage chamber 24 Front axle 25 Rear axle 26 First rear wheel brake cylinder 28 Second calculating S3 of the rear wheel brake cylinder 30 first front wheel brake cylinder 31 and the second front wheel brake cylinders 42, 43 pump S1 first calculation of the brake fluid volume _{V 1} S2 second brake fluid volume _{V 2} second calculating V ₁ of the third brake fluid volume _{V 3} first brake fluid volume V ₂ second brake fluid volume V ₃ third brake fluid volume

Claims (10)

A method for operating an automotive brake system (1), comprising:
Calculating a _first brake fluid volume (V ₁ ) moved from the brake master cylinder (10) into the brake system (1) by operating the brake pedal (2) by the driver of the vehicle (S1); ,
Calculating a _second brake fluid volume (V ₂ ) in the wheel brake cylinders (26, 28, 30, 31) of the brake system (1) (S2);
Using the calculated first brake fluid volume (V ₁ ) and the calculated second brake fluid volume (V ₂ ), at least one storage chamber (20, 22) of the brake system (1). (S3) calculating a _third brake fluid volume (V ₃ ) within
A method that includes Calculating the _first brake fluid volume (V ₁ ) moved from the brake master cylinder (10) into the brake system (1) by the driver of the vehicle operating the brake pedal (2). (S1) is the diameter (D) of the brake master cylinder (10) and the output rod of the brake system (1) coupled to the brake pedal (2), detected by a pedal stroke sensor (13). The displacement distance of (3) and the displacement distance of the output rod (3) for closing the compensating connection (4) of the brake master cylinder (10). 2. The method according to 1. The step (S2) of calculating the _second brake fluid volume (V ₂ ) in the wheel brake cylinders (26, 28, 30, 31) of the brake system (1) is performed by using the wheel brake cylinder (26). , 28, 30, 31) and the stiffness of the brake system (1). The second brake fluid volume (V ₂ ) in the wheel brake cylinders (26, 28, 30, 31) of the brake system (1) is transferred to the wheel brake cylinders (30) of the front axle (24) of the vehicle. , 31), and calculating by adding the brake fluid volume in the wheel brake cylinders (26, 28) of the rear axle (25).   The brake fluid pressure in the wheel brake cylinders (30, 31) of the front axle (24) is measured by a pressure sensor (5) in the area of the brake master cylinder (10), and the wheel brake of the rear axle (25) is measured. The brake fluid pressure in the cylinder (26, 28) corresponds to the brake fluid pressure in the at least one reservoir (20, 22) of the brake system (1), and the wheel of the rear axle (25) The method according to claim 4, characterized in that the brake fluid pressure in the brake cylinder (26, 28) is between 1.2 and 1.6 bar. The step (S3) of calculating the _third brake fluid volume (V ₃ ) in the at least one storage chamber (20, 22) of the brake system (1) is performed by the first brake fluid volume ( The method according to claim ₁ , wherein the method is performed by calculating a difference between V ₁ ) and the second brake fluid volume (V ₂ ). Determining whether the calculated third brake fluid volume (V ₃ ) in the at least one storage chamber (20, 22) of the brake system (1) is above a preset threshold; The torque coordination between the regenerative brake torque generated by the brake system and the brake torque generated hydraulically by the brake system (1) is terminated. Method. When the calculated third brake fluid volume (V ₃ ) in the at least one storage chamber (20, 22) of the brake system (1) exceeds a preset threshold value, 8. The method according to claim 1, further comprising operating a pump for emptying one storage chamber. 9. In the step (S2) of calculating the _second brake fluid volume (V ₂ ) in the wheel brake cylinders (26, 28, 30, 31) of the brake system (1), the first front wheel A brake fluid volume in the brake cylinder (30), a brake fluid volume in the second front wheel brake cylinder (31), a brake fluid volume in the first rear wheel brake cylinder (26), and a second 9. The method according to claim 1, further comprising calculating a brake fluid volume in the rear wheel brake cylinder. In the automotive brake system (1),
The first brake fluid volume (V ₁ ) moved from the brake master cylinder (10) into the brake system (1) by the driver of the vehicle operating the brake pedal (2) is calculated, and the brake system ( The second brake fluid volume (V ₂ ) in the wheel brake cylinders (26, 28, 30, 31) of ₁ ) is calculated, and the calculated _first brake fluid volume (V ₁ ) and the calculated second brake fluid volume (V ₁ ) are calculated. Using the second brake fluid volume (V ₂ ) to calculate a _third brake fluid volume (V ₃ ) in at least one storage chamber (20, 22) of the brake system (1). A brake system (1) including an installed arithmetic unit (6).

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