Gas Sensor Interlaminar Bonding Layer Microcavity Prevention
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Solution Overview
Problem
Conventional three-chambered gas sensors often experience issues with microcavities forming during manufacturing, leading to communication between internal spaces and external oxygen, which increases light-off time and results in inaccurate NOx concentration measurements due to oxygen diffusion.
Innovation Solution
Incorporating an interlaminar bonding layer that projects into the third internal space, bonding the bottom and side surfaces of the sensor element, preventing microcavity formation and ensuring proper sealing, thus reducing oxygen influx and enhancing measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ceramic green sheets are bonded and laminated to form a sensor element, then the sensor element structure is formed, but unbonded spaces (microcavities) may form between layers causing oxygen diffusion into internal spaces
Solution Approach 1:
The patent applies bonding paste to the ceramic green sheets before lamination in advance, ensuring that the paste is positioned to fill potential gaps. This preliminary application of bonding material prevents unbonded spaces from forming during the lamination process, thereby maintaining sealing integrity while enabling the manufacturing process.
Solution Approach 2:
The bonding paste serves as an intermediary substance between the ceramic green sheets during lamination. It fills and seals potential gaps and unbonded spaces that form between layers, preventing oxygen diffusion into internal spaces while allowing the layers to be bonded together.
2Adaptability or versatility
If a three-chambered sensor element is manufactured using conventional lamination, then the sensor can detect NOx concentration, but unbonded spaces form and cause oxygen to diffuse into the third internal space increasing light-off time
Solution Approach 1:
The bonding paste is applied in advance to specific areas of the ceramic green sheets that correspond to potential unbonded space locations. This preliminary positioning ensures that when lamination occurs, the paste immediately fills gaps and prevents oxygen diffusion pathways, thereby reducing light-off time while maintaining detection capability.
Solution Approach 2:
The patent converts the potentially harmful unbonded spaces into beneficial sealed structures by using bonding paste to intentionally fill and seal these spaces. The paste transforms the harmful oxygen diffusion pathways into beneficial sealed regions, eliminating oxygen influx and reducing light-off time.
3Strength
If bonding paste is applied during manufacturing, then layers can be bonded together, but variations in application or lamination may still create unbonded spaces
Solution Approach 1:
The bonding paste is applied to specific local areas of the ceramic green sheets rather than uniformly across all surfaces. This localized application targets regions where unbonded spaces are most likely to form, ensuring strong bonding where needed while accepting that other areas may have minimal paste presence, thereby achieving both bonding strength and precision.
Solution Approach 2:
The patent changes the parameters of the bonding paste application, such as the amount, viscosity, or drying conditions, to optimize both bonding strength and uniformity. By adjusting these parameters, the paste can fill gaps effectively while maintaining consistent bonding quality across all layers, reducing variation in manufacturing 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 effectively prevents increases in light-off time and abnormal measurements by eliminating microcavities, ensuring precise NOx concentration detection and reducing oxygen interference.
Implementation Method 1
A gas sensor according to claim 1 includes a sensor element including a plurality of layers that are bonded and that each formed of an oxygen-ion conductive solid electrolyte
Implementation Method 2
a measuring electrode that is provided in one of the at least one internal space and has an ability to reduce the gas component of the measurement gas to identify a concentration of the gas component on the basis of a current flowing through the solid electrolyte
Implementation Method 3
an interlaminar bonding layer bonding the first layer and the third layer, the interlaminar bonding layer projecting into the internal space
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
Provided is a gas sensor free from an unbonded space being in communication with an internal space. A gas sensor, which includes a sensor element including a plurality of layers that are bonded and formed of an oxygen-ion conductive solid electrolyte and which reduces a predetermined gas component of a measurement gas to identify a concentration of the gas component on the basis of a current flowing through the solid electrolyte, includes an internal space in which a measurement gas having the ability to reduce the gas component is provided. Of the plurality of layers, an interlaminar bonding layer, which bonds a layer forming a bottom surface of the internal space and a layer forming a side surface of the internal space, projects into the internal space.