Intake Air Sensor Circuit Board Orientation for Low Pressure Loss
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Solution Overview
Problem
Conventional physical quantity detection devices for intake air in internal combustion engines face challenges in maintaining size and reducing pressure loss, especially when multiple sensors are integrated, leading to increased size and potential degradation of flow speed sensitivity and noise performance.
Innovation Solution
A physical quantity detection device with a circuit board accommodated in a unit on the upstream side of a sub-passage, disposed parallel to the flow, and a sub-passage configured to minimize fluid resistance, allowing for the integration of multiple sensors while maintaining compact size and low pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensors are integrated on the circuit board, then the detection functionality is improved, but the circuit board size is enlarged
Solution Approach 1:
The patent transitions from planar circuit board layout to a three-dimensional configuration by having the circuit board extend in the flow direction (longitudinal dimension) rather than only in the width direction. This dimensional change allows multiple sensors to be arranged along the flow path, maintaining compact width while accommodating enhanced detection functionality.
Solution Approach 2:
The circuit board is nested within the measuring unit structure, with sensors positioned to protrude into the flow path. The circuit board accommodates multiple sensors (temperature, humidity, pressure) in a compact arrangement where components are integrated within the available space of the measuring unit, similar to nested dolls occupying space efficiently.
2Adaptability or versatility
If the circuit board size is increased to accommodate multiple sensors, then the detection functionality is improved, but the size of the measuring unit is enlarged
Solution Approach 1:
The measuring unit size in the width direction is maintained by extending the circuit board and sensor arrangement along the flow direction (longitudinal dimension). This dimensional redistribution allows enhanced functionality without increasing the overall width or volume of the measuring unit.
3Area of stationary object
If the circuit board is disposed perpendicular to the flow, then the circuit board size is reduced, but the size in the thickness direction is enlarged
Solution Approach 1:
The patent employs an asymmetric orientation where the circuit board is disposed parallel to the flow direction rather than perpendicular, creating an asymmetric layout that optimizes the distribution of dimensions. This asymmetric arrangement reduces the thickness direction size while accommodating the circuit board along the flow path.
4Adaptability or versatility
If sensors are installed in the circuit board, then the detection functionality is improved, but the flow speed sensitivity is degraded due to turbulence
Solution Approach 1:
The patent applies local quality by positioning sensors at specific locations where they protrude into the flow path without completely obstructing it. The flow sensor is placed in a sub-passage with optimized geometry to minimize turbulence, while temperature and humidity sensors are positioned to detect gas properties without significantly disrupting flow patterns. This localized sensor placement maintains flow speed sensitivity while enabling multifunctional detection.
5Length of stationary object
If the circuit board is disposed parallel to the flow, then the size in the longitudinal direction is reduced, but the pressure loss increases
Solution Approach 1:
The patent optimizes the geometric parameters of the sub-passage and sensor positioning to minimize pressure loss. The circuit board and sensors are configured with specific dimensions and spacing that reduce flow resistance while maintaining compact longitudinal size. Parameters such as passage cross-sectional area, sensor protrusion distance, and passage geometry are optimized to balance size reduction with pressure loss minimization.
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 enables efficient detection of multiple physical quantities with reduced size and pressure loss, enhancing flow speed sensitivity and noise performance, and improving the accuracy and reliability of intake air measurements.
Implementation Method 1
a sub-passage in which a flow sensor is disposed
Implementation Method 2
a sensor that detects the plurality of physical quantities
Data Source
AI summary
To obtain a low-pressure-loss physical quantity detection device that can detect a plurality of physical quantities of intake air. A physical quantity detection device of the present invention that detects a plurality of physical quantities of a measured gas flowing in a main passage, the physical quantity detection device includes: a circuit board on which a sensor that detects the plurality of physical quantities and an electronic component that controls the physical quantities are mountable; a circuit board accommodating unit that accommodates the circuit board; and a sub-passage in which a flow sensor is disposed. The circuit board is accommodated in the circuit board accommodating unit on an upstream side of the sub-passage, and disposed in parallel with the measured gas flowing through the main passage.