Sensor Unit Collision Wall Intake Air Flow Generation
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Solution Overview
Problem
Conventional sensor units in internal combustion engine intake systems face challenges in accurately detecting intake air pressure due to the risk of foreign matter entering the pressure receiving chamber through large pressure introduction holes, and the potential for liquid substances to adhere or freeze in labyrinth structures, obstructing the pressure introduction path.
Innovation Solution
The sensor unit incorporates a case with a first and second passage that communicate with each other and open to the intake passage, exposing the sensor's detection part to the intake air. A collision wall guides the intake air, generating a flow that prevents adhesion or freezing of liquids and foreign matter, ensuring accurate detection of intake air state quantities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a large passage area is used in the pressure introduction hole, then the pressure detection is simple and direct, but foreign matter can easily enter the pressure receiving chamber and obstruct the pressure introduction path
Solution Approach 1:
The pressure introduction path is divided into multiple segments: a first passage with larger passage area for direct pressure transmission, and a second passage with smaller passage area for filtered pressure transmission. This segmentation allows the system to benefit from both the simplicity of direct pressure detection and the reliability of foreign matter filtering.
Solution Approach 2:
The second passage acts as an intermediary element between the intake passage and the pressure receiving chamber. It serves as a filtering mechanism that prevents foreign matter from directly entering the pressure receiving chamber while still allowing pressure transmission, thus mediating between the need for simple detection and the need for reliable detection.
2Reliability
If a labyrinth structure is used to prevent foreign matter entry, then foreign matter is blocked from entering the pressure introduction chamber, but liquid substances may adhere to the passage interior and freeze, narrowing or blocking the passage
Solution Approach 1:
The pressure introduction path is segmented into two passages with different functions: the first passage maintains a larger passage area to prevent liquid adhesion and freezing, while the second passage provides a filtering function. This segmentation resolves the contradiction by assigning different roles to different segments of the same system.
Solution Approach 2:
Different regions of the pressure introduction path are given different qualities: the first passage has a larger passage area optimized for preventing liquid adhesion and freezing, while the second passage has a smaller passage area optimized for filtering foreign matter. This local differentiation allows each region to perform its specific function effectively.
3Reliability
If the passage area is reduced in the labyrinth structure, then foreign matter entry is prevented, but the passage becomes more susceptible to freezing and blockage by liquid substances
Solution Approach 1:
The system segments the pressure introduction path into two passages with different passage areas. The first passage with larger area ensures reliable pressure transmission and prevents freezing, while the second passage with smaller area provides foreign matter filtering. Both passages work together to ensure measurement precision.
Solution Approach 2:
The second passage serves as an intermediary filtering stage that prevents foreign matter from reaching the pressure receiving chamber, while the first passage acts as a backup pathway that ensures continuous pressure transmission even if the second passage becomes partially blocked, thus maintaining measurement precision.
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 actively generates a flow of intake air in the sensor unit's passages, preventing the adhesion or freezing of substances and ensuring high accuracy in detecting intake air pressure and temperature.
Implementation Method 1
a collision wall, colliding with the intake air flowing through the intake passage in the vicinity of an opening of the second passage
Data Source
AI summary
A sensor unit arranged in an intake pipe of an internal combustion engine includes: sensors, detecting a state quantity of intake air flowing through an intake passage defined by the intake pipe; and a case, accommodating the sensors. The case includes: a first passage and a second passage, communicating with each other and each opening to the intake passage so as to expose detection parts of the sensors to the intake air flowing through the intake passage; and a collision wall, colliding with the intake air flowing through the intake passage in the vicinity of an opening of the second passage.