GB2483348A

GB2483348A - A fluid assembly and a method for controlling a pressure supply unit of the fluid assembly

Info

Publication number: GB2483348A
Application number: GB1114619.8A
Authority: GB
Inventors: Daniel Gosse
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-08-30
Filing date: 2011-08-23
Publication date: 2012-03-07
Also published as: FR2964161B1; DE102010039943A1; GB201114619D0; CN102410186A; CN102410186B; FR2964161A1

Abstract

A method for controlling a pressure supply unit 10, which includes a drive 12 and a pump 14, for a fluid assembly 1, wherein the drive 12 is controlled via control signals in order to implement a pressure and/or fluid delivery requirement. Physical magnitudes, such as the position, acceleration, speed or travel of a movable pump element or structure borne noise, fluid pressure or oscillations are captured and analysed to determine oscillation and/or pulsation emissions in operation, the control signals, such as the shape or duration of the voltage or current feed course, being changed so that the determined oscillation and/or pressure pulsation emissions in operation are below a predetermined limit value, while the efficiency remains essentially the same. Also claimed is the fluid assembly, a computer program product and a computer program to carry out the method.

Description

I

Description Title

Method for controlling a pressure supply unit for a fluid assembly, and corresponding fluid assembly

Prior art

The invention starts from a method for controlling a pressure supply unit for a fluid assembly according to the type of the independent Claim 1. The invention also concerns a fluid assembly, a computer program product and a data processing program to execute the method for controlling a pressure supply unit.

15!n patent application DE 10 2007 038 397 Al, for example, a brake system for a vehicle is described. The described brake system includes a master brake cylinder, a fluid control unit and at least one wheel brake, the fluid control unit, for brake pressure modulation, including, in at least one brake circuit, a changeover valve, a suction valve and a recirculating pump as the pressure supply unit, for each brake circuit. The fluid control unit also has, for each brake circuit, a sliding valve which is connected into a suction line between the recirculating pump and the master brake cylinder, the sliding valve limiting the effective pressure on a suction side of the recirculating pump to a specifiable maximum pressure value.

Disclosure of the invention

In contrast, the method according to the invention for controlling a pressure supply unit for a fluid assembly, and the fluid assembly according to the invention, with the features of the independent claims, have the advantage that oscillations and pulsations in operation in the medium to be conveyed are captured and analysed in order to make *1 operation with low noise and/or pulsation possible by varying the control of the pressure supply unit. In order to capture the oscillations in operation, various measurement methods can be used and various physical magnitudes can be captured and analysed.

This invention includes the use of a captured signal, on the basis of which the control of the pressure supply unit can be optimised with respect to noise emissions and/or conveying capacity.

The core of this invention is sensing the oscillations which are generated by driving the pressure supply unit for a fluid assembly, and using these signals to reduce the oscillations by adjusting electrical magnitudes to control the drive. In a version of the drive as a linear actuator with a movable armature and at least one fixed stator, currents which generate magnetic fields can be regulated by the at least one stator of the linear actuator, with the intended effect that the pressure supply unit works below or at the predetermined "noise limit". Other possibilities are sensing an armature position, e.g. by a capacitive measuring device, or detecting pulses in the medium to be conveyed by means of pressure sensors. Measuring the oscillations via acceleration sensors or piezo elements is also possible, but significantly more expensive than preferred use of structure-borne noise sensors, which are able, even at higher frequencies, to capture and analyse oscillations quickly enough and to make corresponding output signals available. Use of a microphone to capture noise is also possible, but may require high expenditure for filtering. The advantage of the structure-borne noise sensors is not only the high frequency range, but also the comparatively low price.

The method according to the invention for controlling a pressure supply unit, which includes a drive and a pump unit, for a fluid assembly controls the drive correspondingly via control signals in order to implement a pressure and/or fluid delivery requirement. According to the invention, physical magnitudes are captured and analysed to determine oscillation and/or pulsation emissions in operation, the control signals being changed so that the determined oscillation and/or pressure pulsation emissions in operation are below a predetermined limit value, while the efficiency remains essentially the same.

SI (I

The fluid assembly according to the invention includes a pressure supply unit with a drive and a pump unit, an analysis and control unit controlling the drive correspondingly via control signals in order to implement a pressure and/or fluid delivery requirement.

According to the invention, means of capturing physical magnitudes are provided, and the analysis and control unit analyses them to determine oscillation and/or pulsation emissions in operation, the analysis and control unit changing the control signals so that the determined oscillation and/or pressure pulsation emissions in operation are below a predetermined limit value, while the efficiency remains essentially the same.

The fluid assembly according to the invention, with the analysis and control unit, is designed to execute steps of the above-mentioned method, and of a computer program to control steps of the above-mentioned method, when the computer program is executed by the analysis and control unit. The analysis and control unit can primarily be understood as an electrical device such as a controller, which processes and analyses captured sensor signals. The analysis and control unit can have at least one interface, which can be in hardware and/or software form. In a hardware version, the interfaces can be, for example, part of a so-called system ASIC, which contains a very wide variety of functions of the device. However, it is also possible that the interlaces are separate, integrated circuits or consist at least partly of discrete components. In a software version, the interfaces can be software modules, which for example are present on a microcontroller as well as other software modules. A computer program product with program code which is stored on a machine-readable medium such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out the method according to one of the described embodiments when the program on the analysis and control unit is executed, is also advantageous.

By the means and further developments described in the dependent claims, advantageous improvements of the method given in the independent Claim 1 for controlling a pressure supply unit for a fluid assembly and of the fluid assembly given in the independent Claim 5 are possible. * I

It is specially advantageous that as physical magnitudes, position and/or acceleration and/or speed and/or travel of a movable pump element, and/or structure-borne noise and/or pressure and/or oscillations, are captured and analysed.

In an advantageous form of the method according to the invention, the pressure supply unit is permanently operated near the predetermined limit value, in order to ensure the highest possible power yield with the smallest possible noise stress.

In a further advantageous form of the method according to the invention, in order to optimise the determined oscillation and/or pressure pulsation emissions in operation, a voltage course and/or current feed course and/or duration and/or shape of the voltage course and/or current feed course of the drive are adjusted via power electronics, in order to adjust indirectly the acceleration and/or speed and/or travel of the movable pump element.

In an advantageous form of the fluid assembly according to the invention, the drive is implemented as a linear actuator with a movable armature, at least one fixed stator and a pull-back spring which is supported on the stator and a buffer block, the armature being movable in the direction of the stator against the force of the pull-back spring depending on a control current flowing through the at least one stator, the analysis and control unit specifying the value of the control current depending on the determined oscillation and/or pulsation emissions.

In a further advantageous form of the fluid assembly according to the invention, the pump unit is implemented as a piston pump with a movable piston and a pressure chamber, the movable piston being linked mechanically to the armature and the buffer block.

In a further advantageous form of the fluid assembly according to the invention, the capture means include at least one acceleration sensor and/or at least one piezo element and/or at least one structure-borne noise sensor and/or at least one microphone for direct capture of oscillations in operation and/or at least one pressure sensor for direct capture of pressure pulsation in operation. *

Embodiments of this invention can also be used to compensate for changes of the viscosity of the medium to be conveyed because of temperature changes, changed composition of the medium, e.g. inclusion of water, and to reduce wear by structure-borne noise and disadvantageous friction conditions. The control signals include, for example, voltage courses and/or current feed courses, duration of the current feed, duration and/or shape of the brake current feed, and possible current feed pauses to optimise the fluid flow.

Advantageous embodiments of the invention are shown in the drawings and described below. In the drawings, identical reference symbols designate components or elements which carry out identical or analogous functions.

Brief description of the drawings

Fig. 1 shows a schematic block diagram of a fluid assembly according to the invention.

Fig. 2 shows a more detailed block diagram of a possible embodiment of the fluid assembly according to the invention from Fig. 1.

Embodiments of the invention As can be seen in Fig. 1, a fluid assembly I according to the invention includes a pressure supply unit 10 with a drive 12, a pump unit 14 and a fluid block 30. An analysis and control unit 20 controls the drive 12 via control signals, in order to implement a pressure and/or fluid delivery requirement correspondingly.

According to the invention, means 22 for capturing physical magnitudes, which the analysis and control unit 20 analyses to determine oscillation and/or pulsation emissions in operation, are present. The analysis and control unit 20 changes the * control signals so that the determined oscillation and/or pressure pulsation emissions in operation are below a predetermined limit value, while the efficiency remains essentially the same.

As can also be seen in Fig. 1, the analysis and control unit 20 can be implemented as part of the fluid assembly 1, and pass on the corresponding control signals directly to the drive 12 of the pressure supply unit 10. Additionally or alternatively, an analysis and control unit 20', which is arranged outside the fluid assembly I and shown dashed, can be used to analyse the physical magnitudes which are captured using the capture means 22 and to generate control signals. The fluid assembly I can be connected via an interface 28', shown dashed, to the total system, e.g. a vehicle, and use external controllers 20' which are already present. In this way, embodiments of this invention can advantageously use microprocessors which are already present in the motor vehicle and their computing power, in order to evaluate and interpret the physical magnitudes. The calculation of the control signals, which are modified on the basis of the captured physical magnitudes, to control the drive 12 of the pressure supply unit 10, can also be transferred in this way.

As physical magnitudes, the capture means 22 can for example capture and analyse position and/or acceleration and/or speed and/or travel of a movable element of the pump unit 14, and/or structure-borne noise and/or pressure and/or oscillations.

As can be seen in Fig. 2, the drive 12 is implemented as a linear actuator with a movable armature 12.1, at least one fixed stator 12.2 and a pull-back spring 12.3 which is supported on the stator 12.2 and a buffer block 12.4. The armature 12.1 is moved in the direction of the stator 12.2 against the force of the pull-back spring 12.3 depending on a control current flowing through the at least one stator 12.2, the analysis and control unit 20, 20' specifying the value of the control current depending on the determined oscillation and/or pulsation emissions.

As can also be seen in Fig. 2, the pump unit 14 is implemented as a piston pump with a movable piston 14.1 and a pressure chamber 14.2, which is arranged in a fluid block 30. The movable piston 14.1 is linked mechanically to the armature 12.1 and the buffer block 12.4, so that the movement of the armature 12.1 is transmitted to the piston 14.1.

To control fluid modules, fluid control elements 32, 34, 36, which are preferably implemented as solenoid valves, are arranged in the fluid block. A first solenoid valve 32, for example, is implemented as an outlet valve for the pressure chamber 14.2, and a second solenoid valve 34, for example, is implemented as an inlet valve for the pressure chamber 14.2. The capture means 22 can include at least one acceleration sensor and/or at least one piezo element and/or at least one structure-borne noise sensor and/or at least one microphone for direct capture of oscillations in operation and/or at least one pressure sensor for direct capture of pressure pulsation in operation. To capture the oscillation and/or pulsation emissions in operation, embodiments of this invention preferably use at least one structure-borne noise sensor.

Alternatively, acceleration sensors, microphones, sensors based on piezo effects, pressure sensors or capacitive measuring methods, which make sufficiently fast regulation and data processing possible, can be used.

In the shown embodiment, the analysis and control unit 20 has a computing unit 24 to analyse the captured physical magnitudes and to generate the control signals, and power electronics 26 to generate the setting signals for the linear actuator 12.

The method according to the invention for controlling a pressure supply unit 10, which includes a drive 12 and a pump unit 14, for a fluid assembly 1, controls the drive 12 correspondingly via control signals in order to implement a pressure and/or fluid delivery requirement. According to the invention, physical magnitudes are captured and analysed to determine oscillation and/or pulsation emissions in operation, the control signals being changed so that the determined oscillation and/or pressure pulsation emissions in operation are below a predetermined limit value, while the efficiency remains essentially the same. As physical magnitudes, position and/or acceleration and/or speed and/or travel of the movable pump element 14.1, and/or structure-borne noise and/or pressure and/or oscillations, can be captured and analysed. The pressure supply unit 10 is permanently operated near the predetermined limit value, in order to ensure the highest possible power yield with the smallest possible noise stress. In order to optimise the determined oscillation and/or pressure pulsation emissions in operation, a voltage course and/or current feed course and/or duration and/or shape of the * voltage course and/or current feed course of the drive 12 are adjusted via the power electronics 26, in order to adjust indirectly the acceleration and/or speed and/or travel of the movable pump element 14.1.

Embodiments of this invention can be implemented as a switch, device, method, data processing program with program code means, andfor as a computer program product.

Correspondingly, this invention can be implemented completely as hardware, and/or as software, and/or as a combination of hardware and/or software components.

Additionally, this invention can be implemented as a computer program product on a computer-usable storage medium with computer-readable program code, it being possible to use various computer-readable storage media such as hard disks, CD-ROMs, optical or magnetic storage media etc. The computer-usable or computer-readable media can include, for example, electronic, magnetic, optical, electromagnetic infrared or semiconductor systems, devices, apparatuses or distribution media. Additionally, the computer-readable media can include an electrical connection with one or more lines, a portable computer diskette, a direct access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM) or flash memory, an optical lead and a portable CD-ROM.

The computer-usable or computer-readable medium can even be paper or another suitable medium, on which the program is written, and from which it can be captured electrically, for example, by an optical process of scanning the paper or other medium, then compiled, interpreted or if required otherwise processed, and then stored in the computer memory.

Embodiments of this invention make it possible to reduce structure-borne noise emissions by the pump unit 14, which is implemented as a piston pump, the piston 14.1 of which is deflected by the linear actuator 12. The limit stop of the armature 12.1 of the linear actuator 12 is weakened in such a way that an ideal compromise between exciting undesired oscillations and obtaining efficiency is achieved. Oscillations which are generated by pulsations in the pumping process can also be reduced. & r

The core of the invention is sensing the oscillations which the linear actuator 12 generates, and using these signals to reduce the oscillations by adjusting electrical magnitudes to control the actuator 12. In the shown embodiment, control currents which generate magnetic fields are regulated by the at least one stator 122, in order to work below or at the predetermined "noise limit".

Preferably, in order to capture the oscillation and/or pulsation emissions in operation, embodiments of this invention use at least one structure-borne noise sensor as a capture means 22. Alternatively to the structure-borne noise sensor, acceleration sensors, microphones, sensors based on piezo effects, pressure sensors or capacitive measuring methods, which make sufficiently fast regulation and data processing possible, can be used. Embodiments of this invention use the signals of the at least one structure-borne noise sensor to reduce the striking of the armature 12.1 and the piston 14.1 connected to it to the extent that no or a defined structure-borne noise is generated, without reducing the efficiency of the piston pump 14 too greatly.

Analogously to the structure-borne noise regulation, the pressure supply unit 10 is permanently operated near the defined limit value for structure-borne noise, in order to ensure the highest possible power yield with the smallest possible noise stress.

Embodiments of this invention can also be used to compensate for changes of the viscosity of the medium to be conveyed because of temperature changes, changed composition of the medium (e.g. inclusion of water), and to reduce wear by structure-borne noise and disadvantageous friction conditions. Manipulated variables for the control are, for example, voltage courses and current feed courses, duration of the current feed, duration and shape of the brake current feed, and possible current feed pauses to optimise the fluid flow.

The invention is based on the idea that the requirements concerning delivery, efficiency and noise and/or pulsation emissions for pressure supply units in a vehicle brake system are increasing. On the other hand, vehicle brake systems according to the existing prior art become louder with increasing delivery power, so that in reverse, a reduction of the noise and/or pulsation emissions while design, size etc. remain the same can only be achieved with accompanying reduced delivery power, or bought expensively by expensive design means.

Embodiments of this invention adjust the control of the pressure supply unit using the signals of the capture means, in such a way that structure-borne noise and/or pulsations which are caused by a mechanical limit stop or fluid effects are minimised, and the efficiency and/or delivery rate are reduced only minimally. & 4 1

Claims

Claims 1. Method for controlling a pressure supply unit, which includes a drive (12) and a pump unit (14), for a fluid assembly, wherein the drive (12) is controlled correspondingly via control signals in order to implement a pressure and/or fluid delivery requirement characterized in that physical magnitudes are captured and analysed to determine oscillation and/or pulsation emissions in operation, the control signals being changed so that the determined oscillation and/or pressure pulsation emissions in operation are below a predetermined limit value, while the efficiency remains essentially the same.
2. Method according to Claim 1, characterized in that as physical magnitudes, position and/or acceleration and/or speed and/or travel of a movable pump element (14.1), and/or structure-borne noise and/or pressure and/or oscillations, are captured and analysed.
3. Method according to Claim I or 2, characterized in that the pressure supply unit (10) is permanently operated near the predetermined limit value, in order to ensure the highest possible power yield with the smallest possible noise stress.
4. Method according to any one of Claims I to 3, characterized in that in order to optimise the determined oscillation and/or pressure pulsation emissions in operation, a voltage course and/or current feed course and/or duration and/or shape of the voltage course and/or current feed course of the drive (12) are adjusted via power electronics, in order to adjust indirectly the acceleration and/or speed and/or travel of the movable pump element (14.1).
5. Fluid assembly with a pressure supply unit (10), in particular to carry out the method according to any one of Claims I to 4, the pressure supply unit (10) including a drive (12) and a pump unit (14), and an analysis and control unit (20, 20') controlling the drive (12) correspondingly via control signals in order to implement a pressure and/or fluid delivery requirement, characterized by means (22) of capturing physical magnitudes, which the analysis and control unit (20, 4! 20') analyses to determine oscillation and/or pulsation emissions in operation, the analysis and control unit (20, 20') changing the control signals so that the determined oscillation and/or pressure pulsation emissions in operation are below a predetermined limit value, while the efficiency remains essentially the same.
6. Fluid assembly according to Claim 5, characterized in that the drive (12) is implemented as a linear actuator with a movable armature (12.1), at least one fixed stator (12.2) and a pull-back spring (12.3) which is supported on the stator (12.2) and a buffer block (12.4), the armature (12.1) being movable in the direction of the stator (12.2) against the force of the pull-back spring (12.3) depending on a control current flowing through the at least one stator (12.2), the analysis and control unit (20, 20') specifying the value of the control current depending on the determined oscillation and/or pulsation emissions.
7. Fluid assembly according to Claim 5 or 6, characterized in that the pump unit (14) is implemented as a piston pump with a movable piston (14.1) and a pressure chamber (14.2), the movable piston (14.1) being linked mechanically to the armature (12.1) and the buffer block (12.4).
8. Fluid assembly according to any one of Claims 5 to 7, characterized in that the capture means (22) include at least one acceleration sensor and/or at least one piezo element and/or at least one structure-borne noise sensor and/or at least -one microphone for direct capture of oscillations in operation and/or at least one pressure sensor for direct capture of pressure pulsation in operation.
9. Computer program product with program code which is stored on a machine-readable medium, in order to carry out the method according to any one of Claims I to 4 when the program is executed by an analysis and control unit (20, 20').
10. Data processing program with program code means for carrying out the method according to any one of Claims 1 to 4 by an analysis and control unit (20, 20'), when the data processing program is processed by the analysis and control unit (20, 20').
11. Method for controlling a pressure supply unit for a fluid assembly, substantially as hereinbefore described with reference to the accompanying drawings.
12. Fluid assembly substantially as hereinbefore described with reference to the accompanying drawings.