Pressure Tank Sensor Compensation Layer

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Solution Overview

Problem

The production of pressure tanks from fiber-reinforced plastic is complex due to the difficulty in integrating sensors like strain gauges or electronics, which are sensitive to high pressure and temperature, and capacitive sensors struggle with detecting internal changes and irregular surface topographies, leading to inaccurate measurements and potential damage.

Innovation Solution

A pressure tank design featuring a compensation layer between the sensor device and the base body to compensate for unevenness, allowing for improved detection of internal and external changes using an anisotropic material with a sensor device comprising electrical conductors, which can be easily attached and provide robust, wireless signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sensors like strain gauges or electronics are integrated into the base body during production, then measurement accuracy is improved, but device complexity and manufacturing difficulty increase significantly

Engineering Contradiction:
Improvemeasurement accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a compensation layer as an intermediary between the sensor device and the base body. This layer compensates for surface irregularities and simplifies the integration process, allowing sensors to be attached externally while maintaining measurement accuracy. The compensation layer acts as a mediator that bridges the gap between the sensor and the irregular base body surface, resolving the contradiction between measurement precision and device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If sensors are laminated into the fiber composite laminate, then internal mechanical stresses can be measured, but manufacturing complexity increases due to the winding process

Engineering Contradiction:
Improveinternal stress measurementVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of embedding sensors during the complex winding process of fiber composite laminate production, the patent inverts the approach by attaching sensor devices to the external surface of the finished base body. The compensation layer is applied to the external surface to account for irregularities, allowing stress measurement without complicating the manufacturing process. This inversion resolves the contradiction between measurement capability and ease of manufacture.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If capacitive sensors are attached to the outside of the base body, then sensor protection is improved, but measurement precision deteriorates due to inability to detect internal changes

Engineering Contradiction:
Improvesensor protectionVSAvoiddetection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces capacitive sensors with strain gauge-based sensor devices that utilize electrical resistance changes rather than capacitive effects. This substitution allows the sensors to detect internal mechanical stresses and strains more accurately while remaining protected on the external surface. The strain gauges measure dimensional changes directly, providing superior measurement precision compared to capacitive sensors while maintaining sensor protection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Ease of operation

If strain gauge areas are exposed in the base body for signal tapping, then wired connection is enabled, but moisture ingress and base body weakening occur

Engineering Contradiction:
Improvesignal tappingVSAvoidsensor protection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The compensation layer serves as an intermediary that covers the sensor areas on the external surface, preventing moisture ingress and protecting the sensors while still allowing electrical signal tapping. The layer can incorporate conductive elements or provide access points for wiring without exposing the sensors to environmental damage. This resolves the contradiction between ease of operation for signal tapping and reliability through sensor protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate and reliable detection of changes in the pressure tank's state, including internal fuel conditions and external influences, with reduced sensor sensitivity and ease of attachment, preventing potential accidents by allowing early warning of faults or damage.

Implementation Method 1

Deformation of the compensation layer on a side of the compensation layer facing the base body by a first amount causes deformation of the compensation layer on a side of the compensation layer facing the at least one sensor device by a second amount, which is greater than the first amount

Methodology Applied
Scientific EffectAnisotropic deformation: Anisotropy

Implementation Method 2

A resistance value of the conductive layer changes according to a strain

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP3812646B1Pressure tank, system for monitoring a pressure tank and motor vehicle
Publication Date: 2023.07.26 AUDI AG
  • EP3812646B1 patent drawingFigure 1~2
  • EP3812646B1 patent drawingFigure 3~4
  • EP3812646B1 patent drawingFigure 5~6

AI summary

The invention relates to a pressure tank (10), particularly for a motor vehicle, designed for storing compressed fuel, comprising a base body (12) forming a container for receiving the fuel, and at least one sensor device (18) comprising at least one electrical conductor for detecting at least one parameter that allows conclusions to be drawn about the state of the base body (12). A leveling layer (30) is arranged between the at least one sensor device (18) and an outer surface (26) of the base body (12). The leveling layer (30) is designed to compensate for any unevenness on the outer surface (26) of the base body (12), at least in the area of ​​the at least one sensor device (18). The invention further relates to a system for monitoring a pressure tank (10) and a motor vehicle.