Particulate Filter Monitoring via Image Charge Sensors
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Solution Overview
Problem
Current particulate matter filters in automotive emission systems suffer from irreversible efficiency losses due to temperature excursions during regeneration, and existing monitoring methods are costly, complex, and unsuitable for on-board use, failing to detect filter failures effectively.
Innovation Solution
A method using image charge sensors positioned upstream and downstream of the particulate filter to monitor performance by detecting changes in exhaust flow and particulate matter signals, determining the filter's trapping efficiency through threshold comparisons, allowing for early detection of filter deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laboratory grade instruments with optical, gravimetric or electrical methods are used for particulate matter measurements, then measurement precision is improved, but device complexity and cost increase, making them unsuitable for on-board use
Solution Approach 1:
The patent extracts the essential measurement function from complex laboratory instruments by using a simple differential pressure sensor to measure only the pressure differential across the filter, eliminating the need for complex optical, gravimetric or electrical measurement systems while maintaining sufficient measurement capability for filter performance monitoring
Solution Approach 2:
The patent employs inexpensive differential pressure sensors instead of expensive laboratory grade instruments, accepting that these simpler sensors may require more frequent replacement or calibration, thereby making on-board monitoring economically viable
2Measurement precision
If optical measurement techniques are used for particulate matter detection, then measurement precision is improved, but ease of operation deteriorates due to periodic cleaning requirements and high cost
Solution Approach 1:
The patent replaces optical measurement systems with a mechanical/differential pressure-based measurement system that measures pressure differential across the filter, eliminating the need for periodic cleaning of optical components while maintaining measurement capability
3Ease of operation
If differential pressure method is used for detecting particulate filter failure, then ease of operation is improved, but measurement precision deteriorates due to interference effects from ash loading
Solution Approach 1:
The patent uses feedback from the differential pressure sensor to monitor filter loading over time, comparing measured values against threshold criteria to distinguish between normal ash loading and actual filter failure, thereby improving detection precision while maintaining operational simplicity
Solution Approach 2:
The patent establishes predetermined threshold criteria for differential pressure values before operation, allowing the system to proactively identify filter failure conditions when measurements exceed these thresholds, improving detection precision without complex real-time analysis
4Ease of operation
If simple differential pressure monitoring is used for filter failure detection, then ease of operation is improved, but reliability deteriorates due to interference from ash loading in the filter
Solution Approach 1:
The system continuously monitors differential pressure and provides feedback to compare against threshold criteria, enabling reliable distinction between normal ash loading (gradual pressure increase) and filter failure (sudden pressure increase exceeding threshold), thereby maintaining reliability with simple 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 approach enables efficient and cost-effective monitoring of particulate filter performance, distinguishing between properly functioning and deteriorated filters, and triggering alerts for maintenance, without requiring precise sensor measurements or controlled conditions.
Implementation Method 1
Some embodiments utilize an image charge sensor to detect a signal corresponding to a concentration of charged particles in an exhaust stream
Data Source
AI summary
In an apparatus having an internal combustion engine, an exhaust system for transporting engine exhaust from the engine is described. In one example, a particulate filter disposed in the exhaust system is assessed for degradation. The approach may be particularly useful for an image charge sensor.