Platinum Sensor Element with Glass-Ceramic Surface Profiling
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Solution Overview
Problem
Existing flow sensors in exhaust gas systems face accuracy issues due to dirt and soot particle accumulation, which complicates the design and increases production costs, as they require additional heating elements for cleaning.
Innovation Solution
A sensor element with a thin-film structure of platinum or platinum alloy on a ceramic substrate, coated with a glass-ceramic layer featuring a surface profiling, such as a dimple or bump structure, that prevents dirt and soot particles from accumulating by creating micro-vortices, eliminating the need for additional heating elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional heating element is integrated into the temperature measuring element to burn off dirt particles, then the sensor element can remove accumulated dirt and soot particles, but the production costs increase and the structure becomes more complicated
Solution Approach 1:
The invention applies surface profiling (dimple or bump structures) to the outer surface of the glass-ceramic coating, creating curved micro-structures that generate micro-vortices in the exhaust gas flow. These micro-vortices prevent dirt particles from accumulating on the sensor surface, eliminating the need for additional heating elements while maintaining measuring accuracy over extended periods
2Reliability
If an additional heating element is integrated into the temperature measuring element to burn off dirt particles, then the sensor element can remove accumulated dirt and soot particles, but the production costs increase
Solution Approach 1:
The surface profiling with dimple or bump structures is integrated into the glass-ceramic coating manufacturing process, allowing the anti-dirt effect to be achieved through the coating application itself rather than adding separate heating components. This reduces production costs by eliminating additional parts and assembly steps
3Reliability
If an additional heating element is integrated into the temperature measuring element to burn off dirt particles, then the sensor element can remove accumulated dirt and soot particles, but additional energy is consumed
Solution Approach 1:
The micro-structured surface profiling passively prevents dirt accumulation through hydrodynamic effects (micro-vortices) generated by the exhaust gas flow itself, eliminating the need for active heating cycles that consume additional energy. The system uses the existing gas flow to maintain cleanliness without extra energy input
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 surface profiling ensures high measuring accuracy over a long period with reduced production costs and complexity, as it effectively repels dirt and soot particles, maintaining sensor performance without the need for additional cleaning mechanisms.
Implementation Method 1
The surface profiling has a dimple structure and/or a bump structure. The dimples and/or bumps have a diameter which generates micro-vortices in the gas at a given flow velocity
Implementation Method 2
The particles contained in the gas are carried past the surface because of their mass moment of inertia and the laminar flow arising above the micro-vortices
Implementation Method 3
The particles contained in the gas are carried past the surface because of their mass moment of inertia
Data Source
AI summary
A sensor element with a thin-film structure is made of platinum or a platinum alloy. The structure being applied to a ceramic substrate, in particular an Al2O3 substrate and being covered by a glass-ceramic coating. The glass-ceramic coating has an outer surface with surface profiling. A sensor module, a measuring assembly, and an exhaust-gas re-circulation system include the sensor element.