Stacked Electrode Soot Sensor Design for Compact Exhaust Monitoring
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Solution Overview
Problem
Existing soot sensors for internal combustion engines are large and costly due to the requirement of minimum electrode length for sensitivity, leading to manufacturing challenges and increased costs.
Innovation Solution
A sensor design with multiple electrode layers and insulation layers arranged vertically, allowing for reduced size while maintaining sensitivity through strategically placed openings for particle detection, and a porous filter layer to prevent large particles from interfering with measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electrode length is increased to achieve acceptable sensitivity range, then the measurement precision is improved, but the device size and manufacturing cost increase
Solution Approach 1:
The patent transitions from a planar electrode arrangement to a three-dimensional stacked configuration with multiple electrode layers separated by insulating layers. This vertical stacking allows multiple measurement paths to be packed into a compact volume, achieving high sensitivity without increasing the lateral footprint of the sensor component.
Solution Approach 2:
The patent implements a nested structure where multiple electrode layers are stacked within each other, with insulating layers positioned between them. The openings in each layer are aligned to form passages that guide particles through the stacked structure, enabling compact integration of multiple functional elements.
2Measurement precision
If the electrode length is increased to achieve acceptable sensitivity range, then the measurement precision is improved, but the manufacturing cost increases
Solution Approach 1:
By stacking electrodes vertically rather than extending them laterally, the patent reduces the overall component size while maintaining sensitivity. This compact 3D structure requires less material and occupies less space on the substrate, directly reducing manufacturing costs.
Solution Approach 2:
The patent divides the electrode structure into multiple discrete layers separated by insulating layers. This segmentation allows for standardized fabrication processes where each layer can be deposited and patterned independently, improving manufacturability and reducing costs compared to creating a single large planar electrode.
3Volume of moving object
If multiple electrode layers and insulating layers are stacked vertically, then the device size is reduced, but the device complexity increases
Solution Approach 1:
The patent uses vertical stacking to achieve compactness, but manages complexity through systematic design: insulating layers are positioned between electrode layers to provide electrical isolation, and openings in each layer are aligned to form continuous passages. This regular repeating pattern simplifies the design and fabrication process despite the multi-layer structure.
4Measurement precision
If openings are formed in electrode layers and insulating layers to create passages, then particle detection sensitivity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
By forming openings in multiple stacked layers rather than creating a single large opening, the patent increases the probability that particles will encounter an opening in the measurement path. The vertical stacking of multiple opportunities for particle interaction enhances detection sensitivity while the openings can be smaller individually, reducing precision requirements.
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 sensor achieves high sensitivity and compact size, reducing manufacturing costs and effectively detecting soot particles with improved particle size determination capabilities.
Implementation Method 1
The deposited particles reduce the resistance between the electrodes, and this decrease in resistance serves as a measure of the deposited particle mass.
Implementation Method 2
When a predefined resistance threshold is reached, the sensor arrangement with the heating elements is heated, thus burning off the deposited particles.
Data Source
Figure 1a~1b
Figure 1c~2
Figure 3~4
AI summary
The invention relates to a sensor (10) for detecting electrically conductive and/or polarizable particles, in particular for detecting soot particles (30), comprising a substrate (11) and at least two electrode layers (12; 13), a first electrode layer (12) and at least one second electrode layer (13), which is arranged between the substrate (11) and the first electrode layer (12), being provided. At least one insulation layer (14) is formed between the first electrode layer (12) and the at least one second electrode layer (13) and at least one opening (15; 16) is formed in both the first electrode layer (12) and the at least one insulation layer (14), at least some sections of the opening (15) in the first electrode layer (12) and of the opening (16) in the insulation layer (14) being arranged one above the other, such that at least one passage (17, 17', 17'') is formed to the second electrode layer (13).