Sensor Element With Localized Porous Protective Layer
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Solution Overview
Problem
Existing sensor elements with porous protective layers fail to efficiently protect the tip portion from thermal shocks, leading to increased power consumption and reduced responsiveness due to thick protective layers and prolonged gas diffusion times.
Innovation Solution
A sensor element design featuring a cavity on the distal end with a porous protective layer that includes a water droplet blocking structure and a thin portion around it, positioned to avoid the cavity's extension line, reducing thermal capacity and improving responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the porous protective layer is made thick to protect the tip portion from water droplet damage, then the protection effectiveness is improved, but the thermal capacity increases and responsiveness deteriorates
Solution Approach 1:
The porous protective layer is designed with non-uniform thickness, featuring a thick portion (water droplet blocking structure) at the tip portion to provide enhanced protection, and thin portions at other areas to reduce overall thermal capacity. This local differentiation allows the structure to provide maximum protection where needed while minimizing the negative effects of thickness elsewhere.
Solution Approach 2:
The protective layer is segmented into functionally distinct regions: a water droplet blocking structure (convex portion) with thickness of 50-200 μm at the tip portion for protection, and thin portions with thickness of 10-50 μm in other areas for rapid response. This segmentation enables each region to fulfill its specific function optimally.
2Reliability
If the porous protective layer is made thick to protect the tip portion, then the protection effectiveness is improved, but the production time increases
Solution Approach 1:
The protective layer thickness is optimized locally rather than uniformly throughout. The thick water droplet blocking structure (50-200 μm) is applied only to the tip portion where protection is critical, while thin portions (10-50 μm) cover other areas. This reduces the total material quantity and production time while maintaining necessary protection levels.
3Reliability
If the porous protective layer is made thick, then the protection effectiveness is improved, but the heat capacity increases leading to higher power consumption
Solution Approach 1:
The protective layer is designed with thick portions (50-200 μm) only where protection is critically needed (tip portion overlapping the cavity), and thin portions (10-50 μm) elsewhere. This localized thickening provides necessary protection while minimizing the overall heat capacity and associated power consumption for heating the sensor element.
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 design effectively protects the tip portion from water droplet damage, reduces thermal capacity, and enhances the sensor's responsiveness while maintaining productivity and resistance to damage.
Implementation Method 1
a water droplet blocking structure covering at least a part of a distal end surface of the main body
Implementation Method 2
porous protective layer having a water droplet blocking structure
Implementation Method 3
the necessary part can be efficiently protected by the porous protective layer. As a result, the sensor element can reduce the thermal capacity of the distal end, and can improve the responsiveness of the sensor element
Implementation Method 4
a cavity on a distal end side of the main body, the cavity being configured to take in a gas
Data Source
AI summary
A sensor element is equipped with a main body including a cavity for taking in a gas on a distal end side thereof, and a porous protective layer covering an outer peripheral surface of the main body at the distal end side thereof. The porous protective layer is equipped with a water droplet blocking structure covering at least a part of a distal end surface, the part overlapping the cavity in a longitudinal direction, and a thin portion covering the distal end surface around the water droplet blocking structure.