Gas Sensor Protection Layer with Water Separation Space
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Solution Overview
Problem
Conventional gas sensor elements with protection layers formed by dipping processes face issues of excessive heat capacity and power consumption due to uneven thickness, leading to potential breakage from thermal shock and inefficient manufacturing processes like spraying, which results in wasteful slurry use and prolonged operation times.
Innovation Solution
A gas sensor element with a porous protection layer comprising two distinct layers, where a separation portion is introduced between the layers in the forward region to accumulate water, reducing the overall thickness and heat capacity, and preventing direct adhesion to the element body, while maintaining sufficient contact area to prevent layer separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection layer is formed by a dipping process to ensure sufficient thickness at vertexes, then the protection against thermal shock is improved, but the heat capacity and power consumption increase excessively
Solution Approach 1:
The invention applies different thicknesses of the protection layer to different regions of the element body. The vertexes have a first thickness sufficient for thermal shock protection, while the central portions have a smaller second thickness, reducing overall heat capacity and power consumption while maintaining reliability at critical locations.
2Productivity
If the protection layer is formed by a spraying process to reduce slurry application time, then the manufacturing efficiency is improved, but slurry waste increases significantly
Solution Approach 1:
The invention segments the protection layer formation into two distinct dipping steps: first applying slurry to vertexes and edge portions, then applying slurry to central portions. This segmentation allows precise control of slurry application, reducing waste while maintaining manufacturing efficiency.
3Reliability
If the protection layer is made uniformly thick to ensure adequate protection at all areas, then the reliability is improved, but the heat capacity and activation time increase
Solution Approach 1:
The invention implements local quality by providing the protection layer with different thicknesses in different regions. Vertexes receive a first thickness for thermal shock protection, while central portions receive a smaller second thickness, reducing overall heat capacity and activation time while maintaining adequate protection where needed.
4Reliability
If multiple dipping operations are performed to ensure sufficient protection layer thickness at vertexes, then the protection against thermal shock is improved, but the manufacturing time and complexity increase
Solution Approach 1:
The invention segments the protection layer formation into two controlled dipping steps with different slurry application regions. This segmentation achieves adequate protection at vertexes without requiring multiple repetitions of the same dipping process, simplifying the overall manufacturing procedure while maintaining reliability.
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 reduces the heat capacity and power consumption of the gas sensor element, enhances resistance to thermal shock, and simplifies the manufacturing process by minimizing slurry waste and operation time, thereby improving the reliability and efficiency of the gas sensor.
Implementation Method 1
The protection layer has a certain thickness for allowing condensed water to evaporate before reaching the element body
Implementation Method 2
at least one separation portion which assumes the form of a space between the first layer and the second layer and is formed only in a forward region
Implementation Method 3
The protection layer has a certain thickness for allowing condensed water to evaporate before reaching the element body
Data Source
AI summary
A gas sensor element in an air/fuel ratio sensor includes an element body and a protection layer having two layers (a first layer and a second layer). The gas sensor element has at least one separation portion in the form of a space between the first layer and the second layer. The gas sensor element can temporarily accumulate, in the at least one separation portion, water which adheres to the surface of the protection layer and penetrates into the protection layer. Thus, as compared with a protection layer which is identical in thickness to the protection layer, but does not have separation portions, water adhering to the protection layer is less likely to reach the element body. Therefore, there can be restrained breakage of an end of the element body which could otherwise result from thermal shock stemming from adhesion of water.