Particulate Filter Soot Mass Correction for Cold Start Regeneration
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Solution Overview
Problem
Current methods for regenerating particulate filters in diesel engines face inaccuracies in estimating soot mass due to factors like NO2 emissions, partial oxidation, and water condensation, leading to frequent or infrequent regenerations that can cause engine service issues.
Innovation Solution
A method that measures a parameter representative of soot mass in the filter, adjusts for cold start conditions by freezing the pre-shutdown mass and incrementing it with stable differences, and uses this corrected value for regeneration, ensuring accurate soot estimation and avoiding distortion from condensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If differential pressure measurement is used to estimate soot mass, then the regeneration triggering is simplified, but the measurement precision deteriorates under cold start conditions due to water condensation reorganizing soot and releasing channels
Solution Approach 1:
The system performs preliminary detection of cold start conditions before differential pressure measurement is used for soot mass estimation. By detecting temperature conditions in advance, the system can apply correction algorithms or alternative measurement methods specifically tailored for cold conditions, thereby maintaining measurement precision without compromising the simplicity of the overall system.
2Ease of operation
If regeneration is triggered based on differential pressure threshold, then the control process is simplified, but the reliability deteriorates due to inaccurate soot mass estimation causing premature or delayed regenerations
Solution Approach 1:
The system implements feedback mechanisms that continuously monitor differential pressure, temperature, and other relevant parameters. Based on this feedback, the system dynamically adjusts the regeneration triggering decision, applying correction factors for cold conditions and considering the rate of change of differential pressure. This feedback loop maintains reliable regeneration timing while keeping the control process relatively simple through rule-based decision logic.
3Device complexity
If differential pressure measurement is used without cold condition correction, then the device complexity is reduced, but the measurement precision worsens due to condensation effects on soot structure
Solution Approach 1:
The system changes the interpretation and processing of the differential pressure parameter based on temperature conditions. When cold conditions are detected, the system applies correction algorithms that account for condensation effects on soot structure, effectively adjusting the measurement parameter without adding complex hardware. This approach maintains device simplicity while improving measurement precision through software-based parameter adaptation.
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 improves the accuracy of soot mass estimation, reducing the likelihood of premature or delayed regenerations, thus maintaining engine performance and preventing service disruptions.
Implementation Method 1
particulate filter placed in the exhaust line of a heat engine... soot trapped by the filter
Implementation Method 2
partial and non-homogeneous oxidation of the soot stored in the filter occurs... soot trapped by the filter is not burned during its regeneration
Data Source
Figure 1~2
Figure 3~4
AI summary
The method for regenerating a particulate filter (4) in the exhaust system (3) of a combustion engine (1) involves the following steps: (a) every time the combustion engine is started, a parameter representative of the condition of the combustion engine and/or of the exhaust system is measured, (b) when the measured parameter reveals that the engine and/or the exhaust system are cold, the parameter representative of the mass of accumulated soot measured before the engine was last turned off is frozen, (c) the deviation between the frozen mass parameter and the parameter representative of the mass measured at time t is continuously determined, and (d) when the deviation has been resolved by convergence, it is added to the frozen mass parameter and the resulting corrected value is used in the ongoing regeneration process.