Sensor Element Air Introduction Portion Aspect Ratio Optimization
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Solution Overview
Problem
Conventional sensor elements for detecting specific gas components face challenges in reducing power consumption while maintaining sufficient air supply to the reference electrode, often resulting in increased overall heat capacity and thermal conduction inefficiency due to large air introduction portions, which can lead to insufficient air supply if reduced excessively.
Innovation Solution
A sensor element with a plate-shaped design featuring a detection portion and an air introduction portion as a longitudinal hole, where the cross-sectional area and aspect ratio of the air introduction portion are optimized to 0.015 to 0.147 mm² and 0.0082 to 0.0800, respectively, to balance thermal conduction efficiency and air supply, reducing power consumption and preventing insufficient air supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the air introduction portion is made large, then sufficient air supply to the reference electrode is ensured, but the overall heat capacity increases causing deterioration of thermal conduction efficiency and increased power consumption
Solution Approach 1:
The patent applies parameter changes by precisely controlling the cross-sectional area and aspect ratio of the air introduction portion. By setting the area to 0.01 to 0.15 mm² and the aspect ratio to 0.006 to 0.06, the design optimizes the balance between air supply quantity and thermal conduction efficiency, reducing heater power consumption while ensuring sufficient air reaches the reference electrode.
2Use of energy by moving object
If the air introduction portion is excessively decreased, then power consumption is reduced, but insufficient air supply to the reference electrode occurs
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges for the air introduction portion: cross-sectional area of 0.01 to 0.15 mm² and aspect ratio of 0.006 to 0.06. These parameter changes ensure that even with a reduced air introduction portion size, sufficient air supply to the reference electrode is maintained while achieving lower power consumption.
3Reliability
If the overall heat capacity is increased, then thermal mass is improved, but thermal conduction efficiency deteriorates
Solution Approach 1:
The patent addresses this contradiction through parameter changes in the air introduction portion dimensions. By controlling the area to 0.01 to 0.15 mm² and aspect ratio to 0.006 to 0.06, the design reduces unnecessary thermal mass while maintaining thermal conduction efficiency, preventing energy loss without compromising thermal stability.
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 optimized sensor element achieves reduced power consumption for heating while ensuring a sufficient air supply to the reference electrode, maintaining thermal conduction efficiency and preventing breakage, thereby enhancing the sensor's performance and durability.
Implementation Method 1
the sensor element of JP2005-049115A shows good gas responsivity, rapid temperature rise by the heater and high durability against repeated rapid temperature rises
Implementation Method 2
the overall heat capacity of the sensor element is increased to cause a deterioration of thermal conduction efficiency when the air introduction portion is relatively large in the sensor element
Implementation Method 3
the sensor element generates an electromotive force between the measurement electrode and the reference electrode via the solid electrolyte member according to a ratio between the concentrations of a specific gas component (oxygen) in the gas under measurement and in the air
Data Source
AI summary
Disclosed is a sensor element for detecting a specific gas component in a gas under measurement. The sensor element is plate-shaped in a longitudinal direction thereof and has a detection portion located on a front end side of the sensor element and an air introduction portion adapted as a longitudinal hole extending in the longitudinal direction to a position of the detection portion so as to introduce air thereinto. The detection portion includes a measurement electrode exposed to the gas under measurement, a reference electrode arranged in the air introduction portion and a plate-shaped solid electrolyte member held in contact with the measurement electrode and the reference electrode. The air introduction portion has a cross section with an aspect ratio of 0.0082 to 0.0800 and an area of 0.015 to 0.147 mm2 when taken perpendicular to the longitudinal direction at a position of the reference electrode.