Fibrous Vortex Dispersive Media for Mass Air Flow Sensor

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Solution Overview

Problem

Mass air flow sensors in engine air intake tracts face measurement errors due to turbulence and vortices in the air flow, which are not effectively addressed by existing solutions like straightening vanes or honeycomb structures, as they are costly and not universally applicable.

Innovation Solution

A flow vortex suppression apparatus using air flow permeable fibrous vortex dispersive media, typically a non-woven fleece of natural and synthetic fibers, is installed upstream of the mass air flow sensor to diffuse vortices and reduce turbulence, thereby improving signal quality and noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If straightening vanes or honeycomb structures are installed to reduce turbulence and vortices, then measurement precision is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvemass air flow measurement precisionVSAvoidair intake duct structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies porous absorptive material (such as foam or fibrous material) to the inner surface of the air intake duct, particularly in regions where vortices and turbulent jets form. This porous material dissipates vortex energy through flow resistance and capillary effects, reducing turbulence and improving mass air flow measurement precision without requiring complex structural modifications like honeycomb structures or straightening vanes.

Inventive Principle:
Principle #31Porous materials

2Measurement precision

If straightening vanes or honeycomb structures are installed to reduce turbulence and vortices, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvemass air flow measurement precisionVSAvoidair intake duct manufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent utilizes porous absorptive materials that can be applied as coatings or liners to the air intake duct interior. These materials are cost-effective compared to manufacturing complex honeycomb structures or straightening vanes, while effectively reducing vortex intensity and improving measurement precision through their flow-resistive and energy-dissipating properties.

Inventive Principle:
Principle #31Porous materials

3Measurement precision

If porous absorptive material is applied to reduce vortices, then measurement precision is improved, but the material may trap and hold vortices temporarily

Engineering Contradiction:
Improvemass air flow measurement precisionVSAvoidconsistent vortex suppression performance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent specifies using porous absorptive material with appropriate pore size distribution and flow resistance characteristics that allow vortices to dissipate energy and decay rather than being trapped. The material's capillary effects and flow resistance create gradual deceleration and mixing that promotes vortex breakdown, ensuring consistent performance across varying flow conditions.

Inventive Principle:
Principle #31Porous materials

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 apparatus effectively reduces signal noise and variations in mass air flow measurements by eliminating turbulent jets and vortices, enhancing the reliability of mass air flow sensors and also acts as a filter to trap particulates, thus protecting the sensor and reducing engine noise.

Implementation Method 1

The vortex dispersive media is configured and adapted to diffuse vortices and reduce air turbulence of an air stream entering the mass flow sensor

Methodology Applied
Scientific EffectVortex diffusion:

Implementation Method 2

reduce air turbulence of an air stream entering the mass flow sensor, thereby reducing variations and noise in a flow measurement signal

Methodology Applied
Scientific EffectTurbulence reduction:

Implementation Method 3

acts as a filter to trap particulates, thus protecting the sensor

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP2422168B1Engine air intake mass air flow sensor apparatus with flow vortex suppression apparatus, and engine air intake duct with such a mass air flow sensor
Publication Date: 2019.06.05 MANN HUMMEL GMBH
  • EP2422168B1 patent drawingFigure 1
  • EP2422168B1 patent drawingFigure 2A
  • EP2422168B1 patent drawingFigure 2B

AI summary

In various aspects of the invention a flow vortex suppression apparatus for use in an air intake duct having a mass air flow sensor is disclosed. The flow vortex suppression apparatus includes an air flow permeable fibrous vortex dispersive media installed into the air duct in a position upstream of the mass flow sensor and configured to occlude the air duct such that air flow in the duct is constrained to pass through the vortex dispersive media. The vortex dispersive media is configured and adapted to diffuse vortices and reduce air turbulence of an air stream entering the mass flow sensor, thereby reducing variations and noise in a flow measurement signal from the mass air flow sensor.