Fine Particle Sensor Casing with Overlapping Inlet and Outlet Holes
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Solution Overview
Problem
Conventional fine particle sensors in exhaust pipes of internal combustion engines face variability in detection accuracy due to fluctuations in exhaust gas flow, affecting the reliable measurement of fine particles like soot.
Innovation Solution
A fine particle sensor system that includes an ion generating unit for corona discharge, a charging unit to ionize particles, and an ion trapping unit to generate an output signal based on excess ions, with a casing design that accommodates these units and features gas inlet and outlet holes arranged to minimize the impact of exhaust gas flow variations, ensuring stable detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional fine particle sensor is mounted on an exhaust pipe, then the sensor can detect fine particles in exhaust gas, but the detection accuracy varies depending on the flow of exhaust gas
Solution Approach 1:
The sensor is divided into multiple functional units (ion generation unit, charging unit, ion trapping unit, and casing) that work together to stabilize detection. The casing is segmented with specific inlet and outlet holes to control gas flow independently from particle detection, isolating the measurement process from exhaust flow variations.
Solution Approach 2:
The casing acts as an intermediary structure that mediates between the exhaust gas flow and the ion trapping process. By positioning inlet and outlet holes to overlap when viewed from the arrangement direction, the casing creates a controlled flow path that stabilizes the gas environment around the ion trapping unit, thereby stabilizing detection accuracy regardless of external exhaust flow conditions.
2Stability of the object's composition
If the gas inlet and outlet holes are arranged to overlap, then the flow of exhaust gas is stabilized, but the structural design becomes more complex
Solution Approach 1:
The overlapping arrangement of inlet and outlet holes serves multiple functions simultaneously: it stabilizes gas flow, creates a controlled measurement environment, and enables the casing to act as both a protective enclosure and a flow management structure. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The solution transitions from considering only the linear arrangement of holes to viewing them in a two-dimensional overlapping configuration when viewed from the arrangement direction. This dimensional perspective allows the holes to serve dual purposes of gas introduction and flow stabilization without requiring complex three-dimensional routing.
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 system enhances detection accuracy by stabilizing the flow of exhaust gas and ions, allowing for precise measurement of fine particles regardless of exhaust gas flow fluctuations, thereby improving the reliability of fine particle detection in internal combustion engines.
Implementation Method 1
an ion generating unit that generates ions by corona discharge
Implementation Method 2
a charging unit that charges, with some of the ions generated by the ion generating ions, the fine particles in the exhaust gas
Implementation Method 3
an ion trapping unit that traps a remainder of the ions generated by the ion generating unit, which remain as excess ions without being used for charging of the fine particles
Data Source
AI summary
There is provided a fine particle sensor for detecting fine particles in exhaust gas, including an ion generating unit for generating ions by corona discharge, a charging unit for charging the fine particles by some of the generated ions, an ion trapping unit for trapping a remainder of the generated ions and a casing for accommodating therein the charging unit and the ion trapping unit in a given arrangement direction. The casing has a gas inlet hole and a gas outlet hole formed in a circumferential wall thereof so that the exhaust gas flows in the charging unit through the gas inlet hole and flows out of the ion trapping unit through the gas outlet hole. The gas inlet hole and the gas outlet hole are arranged in such a manner as to at least partially overlap each other when viewed in the given arrangement direction.