Plug-in Sensor Airfoil Profile for Contamination and Pressure Drop

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Solution Overview

Problem

Existing plug-in sensors for measuring fluid parameters in flow tubes, such as hot-film air-mass meters, face issues with contamination and aerodynamically unfavorable designs that lead to pressure drops and unsatisfactory signal reproducibility due to their construction and flow patterns.

Innovation Solution

The design optimizes the arrangement and positioning of outlet openings using airfoil profiles with asymmetrical flow profiles and strategically placed pressure minimums to enhance throughput and minimize contamination, incorporating flow guidance elements to reduce turbulence and improve signal characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a plug-in sensor is used with a bypass duct to prevent contamination, then contamination resistance is improved, but pressure drop increases due to aerodynamically unfavorable shape

Engineering Contradiction:
Improvecontamination resistanceVSAvoidpressure drop
Core Design Contradiction:
Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The plug part is designed with an airfoil profile that creates asymmetrical flow patterns, generating a low-pressure zone on the suction side that enhances contamination resistance while optimizing pressure characteristics

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The airfoil profile introduces curved surfaces that optimize flow attachment and reduce turbulence, improving aerodynamic performance while maintaining contamination protection

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Object-affected harmful factors

If a plug-in sensor with bypass duct is used, then contamination resistance is improved, but signal reproducibility deteriorates due to flow disturbances

Engineering Contradiction:
Improvecontamination resistanceVSAvoidsignal reproducibility
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The asymmetrical airfoil profile creates a low-pressure zone that stabilizes flow patterns and reduces turbulence-induced signal variations, improving reproducibility while maintaining contamination protection

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The flow disturbances that previously degraded signal quality are converted into beneficial low-pressure zones that stabilize flow and improve measurement reproducibility

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If outlet opening is positioned at conventional locations, then manufacturing is simpler, but throughput is reduced due to unfavorable pressure distribution

Engineering Contradiction:
Improveoutlet opening positioningVSAvoidair mass throughput
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The outlet opening is positioned specifically on the suction side where the airfoil profile creates a local low-pressure zone, optimizing throughput while remaining manufacturable

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Positioning the outlet opening at a specific location on the suction side changes the pressure parameter at the outlet, creating a pressure difference that enhances air mass throughput

Inventive Principle:
Principle #35Parameter changes

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 configuration significantly improves air mass throughput, reduces pressure drops, and enhances signal reproducibility by minimizing flow disturbances and pulsation errors, resulting in a more stable and accurate measurement.

Implementation Method 1

The plug part has an airfoil profile which is designed in such a way that when the plug part is introduced into the flowing fluid medium, an asymmetrical flow profile of the fluid medium with a high-pressure side and a low-pressure side is set

Methodology Applied
Scientific EffectAirfoil profile: Aerofoil

Implementation Method 2

at least one outlet opening is arranged on the side of the plug part in the area of this at least one pressure minimum

Methodology Applied
Scientific EffectPressure minimum: Pressure Gradient

Implementation Method 3

The temperature distribution changes in an air flow that is guided over the membrane, which in turn can be detected by the temperature measuring resistors

Methodology Applied
Scientific EffectTemperature distribution changes: Temperature Gradient

Implementation Method 4

At least one heating resistor, which is surrounded by two or more temperature measuring resistors (temperature sensors), is typically arranged on the sensor membrane

Methodology Applied
Scientific EffectHot-film air-mass meter: Joule Heating

Implementation Method 5

at least one flow guidance element which integrates the outflowing fluid into the surrounding flow around the plug part, as a result of which this flow is disturbed as little as possible

Methodology Applied
Scientific EffectFlow guidance: Flow Separation

Data Source

PatentEP2069726B1Plug-in sensor having an optimized flow outlet
Publication Date: 2018.07.11 ROBERT BOSCH GMBH
  • EP2069726B1 patent drawingFigure 1A~1B
  • EP2069726B1 patent drawingFigure 2
  • EP2069726B1 patent drawingFigure 3~4

AI summary

The invention proposes a plug-in sensor (110), which is suitable for determining at least one parameter of a fluid medium flowing in a main flow direction (126), particularly an intake air mass of an internal combustion engine flowing through a flow pipe. The plug-in sensor (110) has a plug part (116) that can be introduced into the fluid medium flowing in a predetermined orientation to the main flow direction (126). At least one flow channel (124) having at least one inlet orifice (128) and at least one outlet orifice (132, 138) is provided in the plug part (116), wherein at least one sensor (144) is received in the at least one flow channel (124) for determining the at least one parameter. The plug part (116) has a profile at which a minimum of at least one local minimum pressure (522) develops in the flowing fluid medium. The at least one outlet orifice (132, 138) is disposed on the side of the plug part (116) in the region of the at least one minimum pressure (522).