Physical Quantity Detection Device Sound Pressure Resonance Attenuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Physical quantity detection devices in internal combustion engines face errors in flow rate detection due to the resonance phenomenon caused by sound pressure from turbochargers, which affects the flow rate characteristics.
Innovation Solution
The device includes a housing with a sub-passage and a circuit chamber, featuring a first pressure introduction passage to communicate between the sub-passage and the circuit chamber, and a second pressure introduction passage to communicate between the circuit chamber and a closed chamber, with protrusions in the circuit chamber to attenuate sound pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional physical quantity detection device with a simple passage structure is used, then the device complexity is low, but the flow rate detection accuracy deteriorates due to sound pressure resonance from the turbocharger
Solution Approach 1:
The device divides the gas flow path into multiple separate passages: a main passage for measurement target gas, a sub-passage for flow rate detection, a circuit chamber, and a closed chamber. This segmentation isolates the flow rate detection unit from direct exposure to turbocharger-induced sound pressure waves, reducing resonance effects and improving measurement accuracy while maintaining a manageable structural complexity through modular design
Solution Approach 2:
The patent introduces a first pressure introduction passage as an intermediary component that connects the sub-passage to the circuit chamber, and a second pressure introduction passage that connects the circuit chamber to the closed chamber. These intermediary passages allow pressure information to be transmitted while physically separating the flow rate detection unit from the high sound pressure environment, thereby reducing resonance impact without completely isolating the detection mechanism
2Reliability
If the diaphragm is directly exposed to the sub-passage without additional pressure introduction passages, then the device complexity is low, but the reliability of flow rate detection deteriorates due to resonance phenomenon
Solution Approach 1:
The first pressure introduction passage is configured to introduce pressure from the sub-passage to the circuit chamber before the sound pressure waves can directly affect the diaphragm. This preliminary pressure transmission ensures that the diaphragm responds to actual flow-induced pressure changes while being protected from subsequent resonance effects caused by turbocharger operation
Solution Approach 2:
The patent adds a spatial dimension to the pressure transmission path by introducing pressure through the circuit chamber as an intermediate space. Instead of direct exposure, pressure changes are transmitted through multiple spatial locations (sub-passage → circuit chamber → closed chamber), effectively separating the detection mechanism from the harmful sound pressure environment while maintaining detection reliability
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 reduces the influence of sound pressure resonance on flow rate characteristics, enhancing the accuracy of flow rate detection in internal combustion engines.
Implementation Method 1
the circuit chamber includes at least one or more protrusions disposed opposite an opening to which the other end of the first pressure introduction passage is open
Data Source
AI summary
An object of the present invention is to provide a physical quantity detection device configured to reduce an influence of a resonance phenomenon of sound pressure on flow rate characteristics. The physical quantity detection device according to the present invention includes: a housing arranged in the main passage; a sub-passage arranged in the housing; a flow rate detection unit arranged in the sub-passage; a circuit unit electrically connected to the flow rate detection unit; a circuit chamber arranged in the housing and accommodating the circuit unit; and a first introduction passage including one end open to the sub-passage and the other end open to the circuit chamber to communicate between the sub-passage and the circuit chamber. The flow rate detection unit includes a diaphragm including a diaphragm front surface exposed to the sub-passage and a diaphragm rear surface exposed to a closed chamber that communicates with the circuit chamber, and the circuit chamber includes at least one or more protrusions arranged opposite an opening to which the other end of the first introduction passage is open.