Flow Property Sensor Contamination Compensation

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Solution Overview

Problem

Existing flow property detection methods, such as thermal air mass meters, are sensitive to contamination, which can lead to measurement errors due to changes in heat conduction and interference around the sensor element.

Innovation Solution

A method and device that utilize a sensor element with a heating element and temperature sensors to detect flow properties by generating correction factors from different measured variables, allowing for the reduction of measurement errors caused by contamination by comparing the influence of contamination on these variables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If thermal air mass meters are used for direct detection of flow properties, then measurement dynamics and detection range are improved, but sensitivity to contamination increases causing measurement errors

Engineering Contradiction:
Improveflow property detection accuracyVSAvoidmeasurement stability under contamination
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention changes the evaluation parameters from single-temperature-point measurements to multi-temperature-point measurements. By measuring temperature at multiple points (at least two different temperature levels) and evaluating the temperature distribution, the system can distinguish between contamination effects and actual flow changes, thereby maintaining measurement reliability while preserving detection accuracy

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention implements feedback by continuously monitoring the temperature distribution pattern and using this information to correct or compensate for contamination effects. The evaluation device analyzes the temperature field and provides feedback signals that allow the system to adapt to contamination conditions, maintaining reliable measurements over time

Inventive Principle:
Principle #23Feedback

2Speed

If sensor elements are exposed to flowing fluid medium for direct measurement, then measurement response time is improved, but contamination of the sensor element occurs leading to heat conduction changes

Engineering Contradiction:
Improvemeasurement response timeVSAvoidsensor contamination
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The invention transitions from single-point temperature measurement to two-dimensional temperature distribution measurement. By measuring temperature at multiple spatial points and evaluating the temperature field pattern, the system can detect contamination effects as distortions in the temperature distribution, allowing continued direct exposure to the fluid while monitoring for contamination

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

The method effectively compensates for contamination-induced drift and errors, providing more accurate flow property measurements by using correction factors derived from the comparison of different measurement signals from the same sensor element.

Implementation Method 1

The sensor element includes at least one heating element and at least two temperature sensors

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

contamination of the sensor element can result in a change in heat conduction and/or a change in heat dissipation to the air

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2758755B1Method for capturing a flow property of a flowing fluid medium
Publication Date: 2019.10.23 ROBERT BOSCH GMBH
  • EP2758755B1 patent drawingFigure 1
  • EP2758755B1 patent drawingFigure 2
  • EP2758755B1 patent drawingFigure 3

AI summary

A method for capturing at least one flow property of a flowing fluid medium (120) is proposed, wherein at least one sensor element (116) is used. The sensor element (116) comprises at least one heating element (122) and at least two temperature measuring sensors (124). The sensor element (116) is used to capture at least one first measurement variable (156) and at least one second measurement variable different from the first measurement variable (156). The first measurement variable (156) and the second measurement variable can be influenced by the flow property. At least one correction, in particular at least one correction factor and/or at least one correction vector, is generated from the first measurement variable (156) and the second measurement variable. The flow property is determined from the first measurement variable (156) and the second measurement variable, taking into account the correction.