Flow Detection Device with Straightening Member for Stable Measurement
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Solution Overview
Problem
Existing flow measurement devices for internal combustion engines face inaccuracies due to uneven fluid flow, dust contamination, and heat loss issues, particularly in low flow velocity conditions, leading to unstable measurement results.
Innovation Solution
A flow detection device with a first channel and a flow straightening member that directs fluid from the entire circumference into the channel, combined with a downstream member to enhance flow velocity and reduce dust ingress, ensuring accurate flow characteristic measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inlet portion is open toward the upstream side to allow fluid flow, then the flow sensor can detect fluid flow, but dust flows in and sticks to the flow sensor making measurement results unstable
Solution Approach 1:
A dust shield member is introduced as an intermediary component between the upstream environment and the flow sensor. This shield member has a dust shield aperture that allows fluid to pass through while blocking dust particles from reaching the flow sensor, thus protecting the sensor from dust contamination while maintaining measurement functionality
Solution Approach 2:
The inlet portion is segmented into multiple functional components: a dust shield member with a dust shield aperture, a flow sensor aperture, and a flow sensor. This segmentation allows the dust shield member to perform the protective function while the flow sensor performs the measurement function, resolving the conflict between openness and protection
2Device complexity
If a deflector smaller than the inlet opening is used, then the structure is simpler, but dust flows into a bypass channel making measurement results unstable
Solution Approach 1:
The dust shield member acts as an intermediary barrier that prevents dust from entering the bypass channel. By positioning the dust shield member upstream of the flow sensor and configuring its aperture appropriately, dust particles are blocked while fluid flow is maintained, preventing dust accumulation in the bypass channel that would otherwise destabilize measurements
3Strength
If thermal sensors with support members are used, then the sensor is structurally supported, but heat is lost to the support member instead of the fluid degrading detection accuracy
Solution Approach 1:
The harmful heat conduction path through the support member is extracted and eliminated. The flow sensor is designed to be supported in a manner that minimizes or eliminates direct thermal contact with support members that would conduct heat away from the fluid. This allows the thermal sensor to transfer heat primarily to the fluid for accurate measurement rather than losing heat to structural supports
4Measurement precision
If the central member is enlarged to obstruct the main passage to increase flow velocity, then detection accuracy is enhanced, but the device complexity and space requirements increase
Solution Approach 1:
Instead of uniformly enlarging the central member throughout the passage, the obstruction is applied locally at specific positions where it most effectively increases flow velocity through the measurement channel. The dust shield member and flow sensor aperture are configured to create localized flow acceleration zones that enhance measurement accuracy without requiring a uniformly complex central member structure throughout the entire passage
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 solution stabilizes flow velocity, reduces dust contamination, and enhances detection accuracy by ensuring consistent heat transfer, resulting in more reliable flow measurements even in conditions with asymmetrical flow and low velocity.
Implementation Method 1
a flow sensor generates heat, and the amount of heat radiated from the flow sensor to fluid is detected to thereby measure the flow amount
Implementation Method 2
a flow straightening member that is provided upstream of the first channel... the fluid flows from substantially the entire circumference of the flow straightening member into the first channel
Implementation Method 3
the outlet portion of a bypass passage is obstructed by a downstream member... the flow velocity of fluid flowing through the bypass passage is increased by the negative pressure produced by fluid flowing through the main passage
Data Source
AI summary
A flow detection device for detecting a flow characteristic of a fluid within a pipe is disclosed. The flow detection device includes a first channel portion that defines a first channel with an upstream aperture. The fluid can flow into the first channel through the upstream aperture. The device also includes a flow sensor disposed in the first channel, and the flow sensor detects the flow characteristic of the fluid. Furthermore, the device includes a flow straightening member that is provided upstream of the first channel. The upstream aperture is hidden by the flow straightening member as viewed looking downstream along an axis of the first channel portion. Also, the fluid flows from substantially the entire circumference of the flow straightening member into the first channel.