Gas Sensor Element Curved Electrolyte Extending Portion
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Solution Overview
Problem
Existing gas sensor elements with zirconia filling portions projecting from alumina sheets face cracking or breaking issues due to structural differences in thickness between the insulating and electrolyte portions, which can lead to conductor layer damage and reduced durability.
Innovation Solution
A gas sensor element design featuring a composite ceramic layer with an insulating portion and an electrolyte portion where the electrolyte portion's thickness is greater than the insulating portion's, with an extending portion that overlays the insulating surface and decreases in thickness towards the periphery, ensuring continuous connection and alleviating stress concentration at the interface, thereby preventing conductor layer cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electrolyte portion thickness is made larger than the insulating portion thickness to improve gas detection performance, then the gas sensor element can better detect oxygen concentration, but the conductor layer may crack or break at the corner of the projected electrolyte portion
Solution Approach 1:
The corner of the electrolyte portion that projects from the insulating portion is rounded with a curved surface instead of a sharp edge. This curvature eliminates stress concentration points at the corner, preventing cracking and breaking of the conductor layer while maintaining the thickness difference needed for effective oxygen detection.
2Ease of operation
If the electrolyte portion projects from the insulating portion to enable wiring connection, then electrical signals can be taken from the electrode, but stress concentration occurs at the corner of the projected portion
Solution Approach 1:
By rounding the corner of the projected electrolyte portion with a curved surface, the design maintains the wiring connection capability while eliminating the sharp corner that causes stress concentration, thereby preserving structural strength at the interface.
3Ease of manufacture
If the thickness of the insulating portion and electrolyte portion are made equal, then manufacturing is simplified, but the gas sensor element cannot effectively detect oxygen concentration in exhaust gas
Solution Approach 1:
The electrolyte portion is designed with non-uniform thickness, being thicker at the center and thinner at the edges where it projects from the insulating portion. This local variation in thickness optimizes both the detection performance (thicker central region) and reduces stress concentration (thinner edge region), while the rounded corner further mitigates stress points.
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 design effectively suppresses cracking and breaking in the conductor layer, enhancing the durability and reliability of the gas sensor element by maintaining a continuous surface connection and reducing stress concentrations.
Implementation Method 1
the through-hole is filled with a zirconia filling portion having oxygen ion conductivity
Data Source
AI summary
A gas sensor element that includes a composite ceramic layer including a plate-shaped insulating portion which contains an insulating ceramic and has a through-hole, and an electrolyte portion which contains a solid electrolyte ceramic, and a portion disposed in the through-hole where the electrolyte portion is thicker than the insulating portion. A first conductor layer is formed over a first insulating surface of the insulating portion and a first electrolyte surface of the electrolyte portion. The electrolyte portion has an extending portion which is overlaid on the first insulating surface and extends toward the outside of the through-hole. The thickness of the extending portion is decreased toward an outer periphery of the extending portion, and the outer periphery of the extending portion is continuously connected to the first insulating surface. A first extending surface of the extending portion continuously connects the first insulating surface and the first electrolyte surface.