Soot Load Estimation Correction for Particulate Filters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for estimating soot load in particulate filters, such as pressure drop based approaches, face limitations during extreme engine-out conditions with varying NOx/PM ratios, leading to less accurate soot load estimates due to changes in soot layer state.
Innovation Solution
A method that applies a soot layer state correction factor to pressure drop based estimation approaches, accounting for changes in soot layer state by calculating a dynamic soot layer state parameter based on the ratio of regeneration to loading rate, which is used to correct soot load estimates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pressure drop based estimation approaches are used to estimate soot load in particulate filters, then the estimation is simple to implement using existing instrumentation, but the accuracy deteriorates during extreme engine-out conditions with varying NOx/PM ratios
Solution Approach 1:
The patent changes the parameter of soot layer state by introducing a dynamic correction factor that accounts for variations in NOx/PM ratios. This correction factor adjusts the pressure drop based estimation to compensate for changes in soot layer characteristics under different engine operating conditions, thereby maintaining accuracy without complicating the overall implementation approach
2Device complexity
If a constant soot layer state assumption is made in pressure drop based estimation, then the calculation remains simple, but the accuracy deteriorates when passive regeneration occurs and soot layer state changes
Solution Approach 1:
The patent transitions from a static assumption of constant soot layer state to a dynamic model that adjusts the soot layer state parameter based on the ratio of passive regeneration rate to soot loading rate. This dynamic approach allows the estimation to adapt to changing conditions during passive regeneration while maintaining relatively simple calculations through the use of a correction factor
3Measurement precision
If the soot layer state is allowed to vary dynamically to improve accuracy during extreme conditions, then the estimation accuracy improves, but the calculation complexity increases
Solution Approach 1:
The patent introduces an intermediary correction factor that mediates between the simple pressure drop based estimation and the complex dynamic soot layer state variations. This correction factor, based on the ratio of regeneration to loading rate, serves as a simplified representation of complex soot layer state changes, allowing accurate estimation without full dynamic modeling complexity
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 enhances the accuracy of soot load estimation throughout all engine operation periods, including extreme conditions, allowing for timely regeneration of the filter by dynamically updating the soot layer state parameter.
Implementation Method 1
a filter is often required to remove particulate matter, such as, for example, ash and soot. Wall-flow particulate filters, for example, are often used in engine after-treatment systems to remove particulates from the exhaust gas.
Implementation Method 2
as a particulate accumulates in the filter, the pressure drop across the filter (e.g., from an inlet end to an outlet end) increases due to the increased restriction of the fluid (e.g., gas) passing through the filter's permeable particulate (e.g., including soot particulate and ash particulate) and porous wall layers.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for regenerating a particulate filter may comprise calculating a soot layer state correction factor based on a rate of regeneration and a rate of particulate loading in the particulate filter and calculating an estimated soot load in the particulate filter based on a pressure drop of an exhaust gas flowing through the particulate filter and the calculated soot layer state correction factor. The method for regenerating the particulate filter may further comprise causing regeneration of the particulate filter when the estimated soot load is greater than or equal to a threshold value.