Soot Mass Estimation Correction for Urea-Fouled Particulate Filters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for estimating soot mass in particulate filters are distorted by clogging caused by urea deposits from SCR systems, leading to overestimation of soot mass and unnecessary filter regenerations.
Innovation Solution
A method that calculates a correlation coefficient based on actual and theoretical pressure criteria to account for urea clogging, allowing for a corrected soot mass estimate and informed filter regeneration strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure-based estimation method is used to determine soot mass in particulate filter, then soot mass can be estimated, but the estimate is distorted by urea deposits causing overestimation
Solution Approach 1:
The patent segments the total pressure drop measurement into two distinct components: one caused by soot accumulation and another by urea deposits. By calculating separate estimation values for each component and then combining them, the method isolates the harmful effect of urea deposits from the measurement of soot mass, thereby eliminating the distortion and overestimation problem.
Solution Approach 2:
The patent introduces an intermediary parameter - the urea deposit estimation value - which acts as a mediator to separate the combined pressure drop effect into its constituent parts. This intermediary allows the system to account for urea deposits independently before determining the final soot mass, preventing direct interference from urea on the soot measurement.
2Reliability
If filter regeneration is triggered based on distorted soot mass estimate, then filter can be emptied, but unnecessary regenerations occur increasing energy consumption
Solution Approach 1:
The patent implements a feedback mechanism where the corrected soot mass estimation (free from urea deposit distortion) is continuously monitored to trigger filter regeneration only when actually needed. This feedback-based control prevents premature or unnecessary regeneration events, thereby reducing energy consumption while maintaining reliable filter operation.
Solution Approach 2:
The patent changes the critical parameter used for regeneration triggering from the distorted soot mass estimate to the corrected soot mass estimation. By modifying this key parameter to reflect accurate soot levels rather than inflated values, the system optimizes regeneration timing and avoids energy-wasting unnecessary operations.
3Device complexity
If total clogging is attributed to soot only, then simple estimation can be performed, but incorrect overload diagnostics result
Solution Approach 1:
The patent segments the clogging analysis into distinct contributions from soot and urea deposits, calculating separate estimation values for each. This segmentation maintains relative simplicity in the overall method while significantly improving diagnostic accuracy by identifying the specific cause of filter overload rather than treating all clogging as soot accumulation.
Solution Approach 2:
The patent introduces additional parameters (urea deposit estimation value and its correlation coefficient) to enhance diagnostic capability. While this increases the number of parameters, it does so in a structured way that improves measurement precision and diagnostic accuracy without excessive 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 prevents overestimation of soot mass and reduces unnecessary regenerations, providing a more accurate diagnosis of filter clogging and optimizing regeneration processes.
Implementation Method 1
a sensor measuring a pressure difference at the terminals of the particulate filter or an absolute upstream pressure
Implementation Method 2
selective catalytic reduction, otherwise known as SCR. The reduction process operates by injection into the exhaust line of a depollution agent called SCR reducer
Implementation Method 3
The reduction process operates by injection into the exhaust line of a depollution agent called SCR reducer
Implementation Method 4
clogging by urea deposits, then in the form of polymers, can take place
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a method for correcting a mass estimate of soot in a particulate filter by taking into account the fouling of said filter with a pollution control agent from an associated SCR reduction system. The method is characterized by calculating the criterion relating to the theoretical pressure (Crit_DPthéo) from the estimated mass of soot, determining a correlation coefficient (K) being the ratio of the criterion relating to the actual pressure (Crit_DPréel) to the criterion relating to the theoretical pressure (Crit_DPthéo), calculating a correlation coefficient (K), the correlation coefficient Kn for the nth update being defined by Kn=ΣCrit_DPPtheo⋅Crit_DPPreelΣCrit_DPPtheo2 where Crit_DPthéo is the criterion relating to the theoretical pressure and Crit_DPréel is the criterion relating to the actual pressure.The determination of an average correlation coefficient (Kmoy) of the coefficients K1 to Kn of the n updates, which is representative of the particulate filter's fouling with pollution control agent, and the consideration of the average correlation coefficient (Kmoy) for updating the calculation method of the estimated soot mass of the particulate filter and/or for quantifying the particulate filter's fouling with pollution control agent. Application in the field of motor vehicles.