Soot Loading Metric for Diesel Particulate Filter Regeneration
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Solution Overview
Problem
There is a need for accurate metrics to determine or estimate the soot loading of diesel particulate filters, which is crucial for effective regeneration and emission control in internal combustion engines.
Innovation Solution
A unique soot loading metric is developed, incorporating the pressure drop across the filter divided by the volumetric flow, with adjustments for turbulent pressure loss mechanisms and fluid viscosity, allowing for precise estimation of soot load using equations and sensor data from an integrated engine-exhaust aftertreatment system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If simple pressure drop measurement is used to estimate soot loading, then measurement simplicity is improved, but measurement precision deteriorates due to turbulent pressure loss mechanisms and viscosity changes
Solution Approach 1:
The patent transforms the simple pressure drop measurement into a corrected soot loading metric by applying parameter changes. Specifically, it divides the pressure drop by volumetric flow rate and applies corrections for turbulent pressure loss mechanisms and fluid viscosity changes. This converts a simple but inaccurate measurement into a precise soot loading indicator without requiring complex additional hardware.
2Device complexity
If existing soot loading methods are used, then device complexity is reduced, but reliability deteriorates due to inaccuracies in soot load determination
Solution Approach 1:
The patent implements a feedback mechanism where the corrected soot loading metric is continuously calculated from pressure drop and flow rate measurements. This metric provides reliable feedback about the actual soot load in the filter, enabling accurate determination of regeneration needs and timing without increasing overall system complexity.
Solution Approach 2:
The patent replaces complex mechanical or physical soot measurement methods with a calculated metric based on fluid dynamics principles. By using the relationship between pressure drop, flow rate, turbulence, and viscosity, it substitutes simple sensor data processing for complex measurement systems while improving reliability.
3Reliability
If regeneration is performed too early or too late, then emission control reliability is maintained, but energy consumption increases due to suboptimal regeneration timing
Solution Approach 1:
The patent enables preliminary action by providing accurate soot loading metrics before regeneration is actually needed. The corrected metric allows the system to predict when regeneration will be necessary, enabling proactive scheduling of regeneration events at optimal moments rather than reacting too early or too late, thus minimizing energy consumption while maintaining emission control reliability.
Data Source
AI summary
One embodiment is a method including a unique soot loading metric. The method includes treating exhaust with a soot filter, sensing information including a pressure differential of the soot filter, a temperature of the soot filter, an ambient pressure, an air flow, and a fuel flow, evaluating the information to determine a value, and commanding a regeneration of the soot filter based upon the evaluating. The evaluating the information to determine the value accounts for a first contribution to the pressure differential attributable to laminar flow wall friction and a second contribution to the pressure differential attributable to turbulent flow. Another embodiment is a system including a unique soot loading metric. The system includes an exhaust aftertreatment subsystem including a soot filter, a controller operable to receive information of a pressure differential of the soot filter, a temperature of the soot filter, an ambient pressure, an air flow, and a fuel flow, to evaluate the information to produce a value, the value accounting for a laminar flow contribution to the pressure differential and a turbulent flow contribution to the pressure differential, and to command regeneration of the soot filter based upon the value.