Flow-rate Measurement Apparatus Dust Protection
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Solution Overview
Problem
Existing flow-rate measurement apparatuses in automotive engines face issues with dust particles entering the intake duct and potentially damaging or contaminating the mass flow measuring element, leading to inaccurate readings and equipment degradation.
Innovation Solution
A flow-rate measurement apparatus design featuring a plate-shaped board with a sensor element mounted on one surface and fluid passages on both sides, incorporating a curved passage portion with a sloping outer-side wall surface that redirects dust particles away from the sensor element, preventing them from hitting the measuring element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mass flow measuring element is placed in the sub-passage to measure intake air, then flow-rate measurement is enabled, but the measuring element may be broken by dust particles or its characteristics may change due to dust adhesion
Solution Approach 1:
The sub-passage is divided into two separate passages: a measurement passage for the mass flow measuring element and a dust discharge passage. This segmentation allows the measuring element to function accurately while dust is diverted away from it, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The harmful dust particles are extracted from the main airflow and directed into a separate dust discharge passage. By removing dust from the measurement path, the measuring element is protected from damage and contamination while maintaining its measurement function.
2Reliability
If a spiral-shaped sub-passage with centrifugal separation is used to protect the measuring element, then dust is redirected to the outer passage, but not all dust particles can be forced into the outer-side sub-passage
Solution Approach 1:
A partition wall is introduced as an intermediary structure within the sub-passage. This partition wall actively directs dust particles toward the dust discharge passage, improving separation effectiveness beyond what centrifugal force alone can achieve, while maintaining measurement accuracy in the inner passage.
3Reliability
If the sub-passage is branched into inner and outer passages with the measuring element in the inner passage, then dust is discharged through the outer passage, but the structure complexity increases
Solution Approach 1:
The measurement function and dust discharge function are merged into a single integrated sub-passage structure. The partition wall creates functional separation while maintaining a compact overall design, reducing complexity compared to completely separate passages while achieving effective dust discharge.
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 dust particles from reaching the mass flow measuring element, enhancing the reliability and accuracy of flow-rate measurements by redirecting them to the backside surface, thus reducing contamination and equipment damage.
Implementation Method 1
the sub-passage includes a curved passage portion which is located upstream of the plate-shaped board and which changes its direction so as to form a curved line
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A plate-shaped board 5 is arranged so that fluid passages are respectively formed at a sensor-element mounting surface side of the plate-shaped board 5 and at a backside surface side thereof being opposed to the sensor-element mounting surface side, a curved passage portion is provided which is located upstream of the plate-shaped board 5 and changes its direction so as to form a curved line, and the curved passage portion has an outer-side wall surface 10G including a sloping portion 10M that slopes so that, of two edge portions of the outer-side wall surface 10G in a direction perpendicular to board surfaces of the plate-shaped board 5, the edge portion located on a sidewall surface, facing the sensor-element mounting surface, of the curved passage portion is positioned closer to an inner wall surface 10P of the curved passage portion than the edge portion located on a sidewall surface opposed to the first sidewall surface, along the sidewall surfaces.