Piezoelectric Pressure Sensor Charge Tap Isolation

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Solution Overview

Problem

Piezoelectric pressure sensors used in high-pressure environments, such as internal combustion engines, are prone to membrane bursting, which allows hot gases to escape and potentially cause damage due to the mechanical weakness of the prestressing sleeve.

Innovation Solution

The piezoelectric pressure sensor design includes a charge dissipation mechanism electrically and mechanically connected to the prestressing body, ensuring a pressure-tight seal even if the membrane bursts, preventing hot gases from escaping into the environment by maintaining a pressure-tight mechanical connection through an electrical feedthrough arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the diaphragm ruptures in high-pressure environments, then hot gases escape into the environment, but the thin-walled preload sleeve breaks quickly under hot gas influence, allowing further damage

Engineering Contradiction:
Improvediaphragm rupture resistanceVSAvoidpreload sleeve mechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies beforehand cushioning by providing a robust protective sleeve that surrounds the preload sleeve and extends into the pressure chamber. This protective structure is designed to withstand hot gas exposure and prevent the thin-walled preload sleeve from breaking when the diaphragm ruptures, thereby cushioning the system against the anticipated thermal and mechanical stress before damage occurs.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent introduces an intermediary protective sleeve that acts as a mediator between the hot gases and the preload sleeve. This intermediate structure absorbs the direct impact of hot gases and prevents them from rapidly degrading the preload sleeve, thereby protecting the internal components while maintaining the necessary mechanical preload function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the preload sleeve is made thin-walled for compact design, then the sensor size is reduced, but it becomes mechanically weak and breaks quickly under hot gas influence

Engineering Contradiction:
Improvesensor housing volumeVSAvoidpreload sleeve strength
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent applies segmentation by dividing the protective structure into two distinct parts: a thin-walled inner preload sleeve that provides compactness and a robust outer protective sleeve that provides mechanical strength and thermal resistance. This segmented approach allows each component to be optimized for its specific function while working together as an integrated system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs composite material principles by combining different structural configurations - the thin-walled inner sleeve and the robust outer sleeve with different wall thicknesses and material properties. This composite structure enables the sensor to achieve both compact size and high mechanical strength under hot gas conditions.

Inventive Principle:
Principle #40Composite materials

3Reliability

If hot gases reach the piezoelectric transducer and bushing after diaphragm rupture, then component damage occurs, but traditional sealing arrangements allow gas escape into the environment

Engineering Contradiction:
Improvecomponent protectionVSAvoidhot gas escape
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The robust protective sleeve serves as an intermediary barrier that prevents hot gases from reaching the piezoelectric transducer and bushing after diaphragm rupture. This intermediate structure maintains the pressure boundary and directs the hot gases away from sensitive components, protecting them from thermal and mechanical damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the vulnerable components (piezoelectric transducer and bushing) from the direct path of hot gas flow by positioning them behind the robust protective sleeve. This extraction isolates the sensitive components from the harmful hot gas environment while maintaining their functional integrity.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This design effectively prevents the escape of hot gases into the environment, ensuring the sensor's integrity and safety even under conditions of membrane failure, maintaining a pressure-tight seal and protecting the internal components from damage.

Implementation Method 1

which piezoelectric transducer the detected pressure profile generates polarization charges

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3124944B1Piezoelectric pressure sensor
Publication Date: 2019.01.23 KISTLER HLDG AG
  • EP3124944B1 patent drawingFigure 1~2
  • EP3124944B1 patent drawingFigure 3
  • EP3124944B1 patent drawingFigure 4

AI summary

The invention relates to a piezoelectric pressure sensor (1) with a sensor housing (20) in which a membrane (21), a piezoelectric transducer (22), an electrode arrangement (23), and a preload element (24.2) are arranged; which membrane (21) detects a pressure profile; on which piezoelectric transducer (22) the detected pressure profile generates polarization charges; which electrode arrangement (23) receives the polarization charges; which electrode arrangement (23) has a charge tap (23.1) and a charge discharge (23.2), which charge tap (23.1) is electrically and mechanically connected to the charge discharge (23.2); and which charge discharge (23.2) is electrically isolated from the preload element (24.2) by a third gap; wherein the charge dissipation (23.2) on a side of the preload body (24.2) facing away from the membrane (21) is connected to the preload body (24.2) via an electrical feedthrough arrangement (27).2) is mechanically connected and separates the third gap from an environment in a pressure-tight manner.