RF Soot Load Estimation in Diesel Particulate Filters
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Solution Overview
Problem
Existing radio frequency sensing methods for determining soot loading in diesel particulate filters are compromised by resonant effects, known as 'sinkholes,' which cause significant attenuation and mask accurate inference of soot load, requiring complex sensors and increased bandwidth and processing capacity.
Innovation Solution
A method that uses a radio frequency sensor to receive mean and standard deviation data, compares it to a threshold to detect sinkhole effects, and adjusts the frequency sweep to avoid affected frequencies, allowing for more accurate soot load inference without requiring full raw data sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a radio frequency sensor uses a frequency sweep to measure soot loading in a diesel particulate filter, then soot load inference is enabled, but resonant effects (sinkholes) cause significant attenuation that compromises measurement accuracy
Solution Approach 1:
The patent extracts and removes the harmful resonant frequencies from the measurement process. By identifying frequency bands where sinkhole effects occur and excluding these bands from the frequency sweep, the measurement system eliminates the source of inaccurate readings while maintaining measurement capability in unaffected frequency ranges.
Solution Approach 2:
The patent segments the frequency spectrum into multiple bands, identifying which bands are affected by resonant effects and which are not. By dividing the frequency sweep into separate bands and selectively processing data from non-affected bands, the system maintains measurement accuracy while avoiding harmful resonant frequencies.
2Measurement precision
If the processor receives and processes complete raw radio frequency attenuation data sets, then measurement accuracy may be improved, but bandwidth requirements and processing capacity requirements increase significantly
Solution Approach 1:
The patent extracts only the necessary data elements (mean attenuation values and standard deviation data from non-affected frequency bands) rather than transmitting and processing complete raw data sets. This extraction approach maintains measurement accuracy while significantly reducing bandwidth requirements and processor complexity.
Solution Approach 2:
Instead of filtering raw data after collection, the patent inverts the approach by pre-identifying and excluding problematic frequency bands before data collection. This prevents unnecessary data from being gathered in the first place, reducing overall system complexity.
3Measurement precision
If standard deviation data exceeds a threshold indicating sinkhole effects, then frequency band selection can be adjusted, but additional processing steps are required
Solution Approach 1:
The patent implements a feedback mechanism where standard deviation data from frequency bands is continuously monitored. When sinkhole effects are detected (standard deviation exceeds threshold), the system automatically adjusts the frequency band selection and excludes affected bands from further processing. This feedback loop maintains measurement accuracy while using efficient automated decision-making.
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 method enables more accurate soot load estimation by mitigating the impact of sinkhole effects, reducing the need for complex sensors and bandwidth, and allowing a single sensor to be used across various diesel particulate filter sizes and configurations.
Implementation Method 1
Radio frequency waves are transmitted across a frequency sweep by the transmitter into the diesel particulate filter. The receiver receives the radio frequency waves once influenced by passage through the diesel particulate filter.
Implementation Method 2
Soot in the diesel particulate filter influences the radio frequency waves during their passage through the diesel particulate filter.
Data Source
AI summary
The disclosed method involves using a radio frequency sensor to estimate soot load in a diesel particulate filter. An engine control module receives a first mean attenuation value derived from attenuation values for a set of radio frequencies within a specific band detected by the sensor. Additionally, first standard deviation data related to the mean attenuation value is received. The method determines whether this standard deviation data exceeds a predefined threshold. If not, the first mean attenuation value is used to infer the soot load. If the standard deviation data threshold is exceeded, a second mean attenuation value from a different set of radio frequencies within another band is obtained. Similarly, second standard deviation data is received. If the second standard deviation data does not exceed the threshold, the second mean attenuation value is used to infer the soot load.