Physical-Quantity Detection Device With Asymmetric Press-Fitting Flange
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Solution Overview
Problem
The existing physical-quantity detection devices for internal combustion engines are prone to variations in mounting position, which affect the air flow rate and deteriorate detection accuracy due to their configuration, including a branch in the auxiliary passage.
Innovation Solution
A physical-quantity detection device with a flange that includes a press-fitting portion for precise positioning within the main passage, an auxiliary passage for gas measurement, a flow rate detector, and an electronic component mounted on a substrate, reducing variations in mounting position and improving flow rate detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a branch is formed in the auxiliary passage, then pollutants can be separated and removed, but mounting position variation affects flow rate detection accuracy
Solution Approach 1:
The auxiliary passage is divided into multiple sections: a first auxiliary passage for main flow and a second auxiliary passage branching off for pollutant separation. This segmentation allows the device to simultaneously achieve pollutant removal and stable flow rate detection by directing different portions of the gas flow through different paths.
Solution Approach 2:
A partition wall is introduced as an intermediary structure that separates the first and second auxiliary passages while maintaining controlled interaction between them. The partition wall with its through-hole allows selective flow distribution, enabling the sensor to detect flow rate accurately while pollutants are diverted through the branched passage.
2Ease of operation
If the device is mounted on the intake passage, then gas flow rate can be measured, but mounting position variation deteriorates detection accuracy
Solution Approach 1:
The flange is designed with an asymmetric press-fitting portion that engages with a corresponding feature on the intake passage. This asymmetric design provides a unique, precise mounting position that eliminates variability in installation, ensuring the sensor consistently measures flow rate at the optimal location regardless of who performs the installation.
Data Source
AI summary
To obtain a physical-quantity detection device that reduces a variation in mounting position in a main passage. A physical-quantity detection device 20 of the present invention is inserted into and disposed in a main passage 22, and includes a flange 211 fixed to a seat surface 103 of the main passage 22, and the flange 211 includes a press-fitting portion 281 for positioning with respect to a seat surface 103 side.