Multilayer Porous Gas Sensor Protection Layer Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing porous protection layers for gas sensor elements in internal combustion engines lack sufficient interlaminar adhesion strength and thermal insulation, leading to separation and heat loss when exposed to water, particularly with increased thickness.
Innovation Solution
A multilayer porous protection layer with an inner region of high porosity, an intermediate region of lower porosity, and an outer region, where the intermediate region has a higher proportion of fine ceramic particles and a smaller thickness, enhancing adhesion and thermal insulation while maintaining gas permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the porous protection layer is made thicker to improve poisoning substance trapping, then the trapping capability is improved, but the interlaminar adhesion strength decreases and layers may separate
Solution Approach 1:
The porous protection layer is divided into multiple layers with different porosity characteristics. The first porous layer has higher porosity for trapping poisoning substances, while the second porous layer has lower porosity to provide structural stability and prevent delamination, resolving the contradiction between trapping capability and adhesion strength
Solution Approach 2:
The protection layer uses a composite structure combining two different porous ceramic materials with distinct porosity values. This composite approach allows the system to simultaneously achieve high poisoning substance trapping (via the high-porosity first layer) and high interlaminar adhesion (via the low-porosity second layer)
Solution Approach 3:
Different regions of the porous protection layer are assigned different porosity qualities tailored to their specific functions. The first layer (inner layer) has high porosity optimized for poisoning substance trapping, while the second layer (outer layer) has low porosity optimized for structural integrity and adhesion, allowing each region to excel at its specific task
2Temperature
If the porous protection layer is made thicker to improve thermal insulation, then the thermal insulation effect is improved, but heat is taken away from the gas sensing portion when wet
Solution Approach 1:
The thermal insulation function is segmented between two porous layers with different porosity values. The first high-porosity layer provides primary thermal insulation, while the second low-porosity layer acts as a barrier to water penetration, preventing heat loss to water while maintaining overall thermal insulation effectiveness
Solution Approach 2:
A composite porous ceramic structure combines materials with different porosity characteristics to achieve both thermal insulation and water resistance. The high-porosity material provides thermal insulation while the low-porosity material prevents water penetration that would cause heat loss, resolving the energy loss contradiction
3Temperature
If the porosity of the inner layer is increased to improve thermal insulation, then the thermal insulation effect is improved, but the adhesion between inner and outer layers is insufficient
Solution Approach 1:
The porous protection layer is segmented into two distinct layers with different porosity values. The first layer (inner layer) has high porosity optimized for thermal insulation, while the second layer (outer layer) has low porosity optimized for adhesion to the element body, allowing each layer to fulfill its specific function without compromising the other
Solution Approach 2:
Different porosity qualities are assigned to different layers based on their functional requirements. The inner layer has high porosity for thermal insulation where it contacts the element body, while the outer layer has low porosity for strong adhesion to the inner layer, creating local optimization that resolves the contradiction
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 improves the interlaminar adhesion strength and thermal insulation of the gas sensor element, preventing separation and heat loss even when wet, while effectively trapping poisoning substances and allowing gas diffusion.
Implementation Method 1
trap poisoning substances and prevent direct contact of water content with the sensing end portion of the gas sensor element
Implementation Method 2
prevent heat from being taken away from the gas sensing portion to the outer layer
Implementation Method 3
a gas sensing portion provided with a solid electrolyte substrate and a pair of electrodes
Data Source
AI summary
There is provided a gas sensor element for detecting the concentration of a specific gas component in gas under measurement, which includes a plate-shaped element body and a porous protection layer. The element body has, at one end portion thereof, a gas sensing portion formed with a solid electrolyte substrate and a pair of electrodes. The porous protection layer has a porous structure formed of ceramic particles and surrounds at least the circumference of the one end portion of the element body. In the present invention, the porous protection layer has an inner region, an intermediate region and an outer region laminated together in order of mention from the element body toward the outside. The intermediate region has a porosity lower than those of the inner and outer regions. There is also provided a gas sensor with such a gas sensor element.