# US 2014/0360360 A1 · Method for determining a position of a piston in a piston pressure accumulator by means of inductive sensors and suitably designed piston pressure accumulator

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- Number: US 2014/0360360 A1
- Document ID: US20140360360A1
- Status: Published application
- Kind: A1
- Application number: 14/370,024
- Filed: 2012-12-27
- Published: 2014-12-11
- Earliest claimed: 2011-12-28
- Assignees: Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Richard Bauer; Christoph Weisser; Ingo Bork; Stefan Weiss; Bernhard Zickgraf; Susanne Spindler
- Web page: https://patentgrep.com/patent/US20140360360A1

## CPC

- F15B 19/005: {Fault detection or monitoring}
- F15B 1/24: with rigid separating means, e.g. pistons
- F15B 2201/205: using gas
- F15B 2201/31: having rigid separating means, e.g. pistons
- F15B 2201/515: Position detection for separating means
- F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR

## Abstract

The invention relates to a piston accumulator (1) and a method for determining a position of a piston (5) that can be moved inside a housing (3) of the piston accumulator (1). One or more inductive sensors (15) are arranged on an exterior surface (21) of the housing (3) and configured to detect a movement of the piston (5) inside the housing (3) caused by electromagnetic induction. In this way, a determination of the current position of the piston (5), which is technically simple to realise and contact-free, can be implemented and used, for example, to monitor a charge state of the piston pressure accumulator (1).

## Claims

### Claim 1

A piston pressure accumulator (1), comprising:
a housing (3), and
a piston (5) movable within the housing (3), and
at least one inductive sensor (15),
wherein the piston (5) is formed using an electrically conductive and/or ferromagnetic material, and
wherein the inductive sensor (15) is arranged on an outside of a casing surface (21) of the housing (3) and is configured to detect a movement of the piston (5) in an interior of the housing (3) on account of electromagnetic induction.

### Claim 2 (depends on 1)

The piston pressure accumulator as claimed in claim 1, wherein the housing (3) is formed, at least in subregions of the casing surface (21), using an electrically insulating and/or diamagnetic material.

### Claim 3 (depends on 1)

The piston pressure accumulator as claimed in claim 1, wherein one or more inductive sensors (15) are arranged on the casing surface (21) of the housing (3).

### Claim 4 (depends on 3)

The piston pressure accumulator as claimed in claim 3, wherein the inductive sensors (15) are arranged along a line parallel to a movement direction (19) of the piston (5).

### Claim 5

A method for determining a position of a piston (5) within a piston pressure accumulator (1), wherein the piston pressure accumulator (1) has a housing (3) and a piston (5) movable within the housing (5), characterized in that the method comprises:
determining the position of the piston (5) by means of at least one inductive sensor (15).

### Claim 6 (depends on 5)

The method as claimed in claim 5, wherein the position of the piston (5) is derived from a changing electromagnetic induction on account of the piston (5) which moves in an interior of the housing (3).

### Claim 7 (depends on 5)

A method for checking an item of information relating to a state of charge of a piston pressure accumulator (1),
characterized in that the method comprises the following steps:
determining a position of a piston (5) within the piston pressure accumulator (1) in accordance with a method as claimed in claim 5, and
checking the information relating to the state of charge of the piston pressure accumulator (1) taking into account a determined position of the piston (5).

### Claim 8 (depends on 7)

The method as claimed in claim 7, wherein the state of charge is ascertained on the basis of a measured pressure and a measured temperature of a fluid within the piston accumulator, and the state of charge which is ascertained in this way is checked taking into account the previously determined position of the piston.

### Claim 9 (depends on 5)

A monitoring apparatus (25) for monitoring a piston pressure accumulator (1), characterized in that the monitoring apparatus (25) is configured to carry out a method as claimed in claim 5.