Meander Strip Conductors for Soot Sensor Integrity
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Solution Overview
Problem
Existing resistive particle sensors for detecting soot in internal combustion engine exhaust gas face challenges in differentiating between the absence of soot and sensor integrity due to conductive connections between strip conductors, and have low sensitivity due to short interaction areas between the conductors.
Innovation Solution
The sensor design features strip conductors that extend in meanders and are capacitively coupled to capacitor elements, which are electrically connected to resistance strip conductors, allowing for the assessment of sensor integrity and improving sensitivity and service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistor connects the strip conductors to establish integrity, then sensor integrity can be verified, but the ability to differentiate absence of soot from deficient integrity is lost
Solution Approach 1:
The patent divides the sensor into separate functional components: strip conductors for soot detection and a separate resistor for integrity verification. This segmentation allows independent optimization of each function - the strip conductors can detect soot without being compromised by the integrity resistor, resolving the contradiction between integrity verification and soot detection accuracy.
Solution Approach 2:
The patent introduces a capacitor element as an intermediary component that couples the strip conductors to the resistor without creating a direct conductive path. This intermediary allows the resistor to verify integrity while the capacitor enables electrical coupling for measurement, resolving the conflict between establishing integrity and maintaining soot detection capability.
2Device complexity
If strip conductors extend in straight lines, then device complexity is reduced, but interaction area and sensitivity are decreased
Solution Approach 1:
The patent transforms the strip conductor geometry from straight lines to meander patterns, effectively adding spatial dimensionality to the interaction area. The meander configuration increases the interaction area between strip conductors and exhaust particles without significantly increasing the footprint, thereby improving sensitivity while maintaining reasonable device complexity.
3Productivity
If capacitor elements are placed inside the exhaust gas exposure area, then sensor response is improved, but service life and measurement accuracy over time are reduced
Solution Approach 1:
The patent extracts the capacitor elements from the exhaust gas exposure area and positions them in a protected location. This extraction removes the vulnerable component from the harsh environment, preserving service life and measurement accuracy over time while maintaining the capacitor's electrical coupling function for sensor operation.
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 enhances the measurement accuracy and service life of the particle sensor by increasing the interaction area between the strip conductors and enabling unambiguous integrity assessment, while improving sensitivity and measurement reliability.
Implementation Method 1
A particle quantity is sensed with the aid of an electrical conductivity between the strip conductors
Implementation Method 2
the strip conductors each end in a capacitor element and are capacitively coupled to this capacitor element
Data Source
AI summary
A resistive particle sensor is described for detecting soot in the exhaust gas of an internal combustion engine, including a sensor element having two strip conductors, which extend spaced apart in meanders in parallel to one another in an area of the sensor element that may be exposed to the exhaust gas, and a resistance strip conductor, the two strip conductors each being capacitively connected via capacitor elements to the resistance strip conductor.