SCRF Efficiency Update via Soot Mass Correction
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Solution Overview
Problem
The efficiency of selective catalytic reduction filters (SCRFs) in exhaust treatment systems is degraded due to the accumulation of soot and ash, which are not effectively removed by thermal regeneration, leading to reduced NOx conversion and reductant oxidation efficiencies.
Innovation Solution
A method and system that utilize a controller to calculate an initial efficiency of the SCRF, determine a soot mass estimate, and apply a soot correction factor to update the efficiency, accounting for soot and ash accumulation, thereby optimizing NOx reduction and reductant management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal regeneration is used to remove particulate matter from the DPF, then soot is burned off, but ash continues to accumulate and cannot be removed
Solution Approach 1:
The patent applies parameter changes by monitoring the mass of particulate matter in the SCRF and using this information to adjust the efficiency calculations and regeneration strategies. The system changes operational parameters based on the accumulated soot and ash levels to optimize performance despite the irreversible ash accumulation.
2Productivity
If the SCRF efficiency is calculated without considering soot accumulation, then calculations are simpler, but the efficiency values become inaccurate due to soot and ash blocking catalytic sites
Solution Approach 1:
The patent implements feedback by continuously monitoring the mass of particulate matter in the SCRF and using this information to update efficiency calculations in real-time. The system measures the actual soot and ash accumulation and feeds this data back into the efficiency model to maintain accurate performance assessment.
Solution Approach 2:
The patent replaces direct physical measurement of efficiency with a calculated model that uses particulate matter mass as a proxy. Instead of measuring catalytic activity directly, the system substitutes a mathematical model that correlates soot and ash accumulation with efficiency degradation.
3Ease of manufacture
If the SCRF and DPF are kept as separate independent components, then each can be optimized for its specific function, but the interaction between soot accumulation in SCRF and catalytic efficiency is not accounted for
Solution Approach 1:
The patent applies universality by creating a unified monitoring and control system that manages both the SCRF and DPF together. The controller uses a single particulate matter mass measurement to inform efficiency calculations for the entire exhaust treatment system, treating the combined system as an integrated unit rather than separate components.
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 NOx reduction models, minimizes reductant consumption, optimizes emissions, diagnostics, and fuel economy by considering particulate matter accumulation in the SCRF, leading to improved overall system performance.
Implementation Method 1
The SCR device uses a reductant capable of reacting with NOx gases to convert the NOx gases into inert byproducts, i.e., nitrogen and water. Once the reductant is in the exhaust stream, the reductant is absorbed into a catalyst of the SCR device, where the catalytic action of the SCR device ultimately converts NOx gases into the inert byproducts.
Implementation Method 2
Once the reductant is in the exhaust stream, the reductant is absorbed into a catalyst of the SCR device
Implementation Method 3
the DPF captures or traps sooty particulate matter and other suspended particulate matter from the exhaust stream
Implementation Method 4
In-situ thermal regeneration of the DPF can be conducted periodically to burn off the accumulated particulate matter
Implementation Method 5
thermal regeneration can be conducted periodically to burn off the accumulated particulate matter
Data Source
AI summary
A vehicle and a method of updating efficiency of a selective catalytic reduction filter (SCRF) of an exhaust treatment system of the vehicle are disclosed. The method includes obtaining an initial calculated efficiency of the SCRF, via a controller, regarding one of a NOx conversion, a reductant absorption, a reductant desorption and a reductant oxidation. The method also includes determining a soot mass estimate in the SCRF representative of an amount of soot collected inside the SCRF and determining a soot correction factor from the soot mass estimate. The method further includes calculating, via the controller, an updated efficiency value of the SCRF by multiplying the soot correction factor and the initial calculated efficiency to update efficiency of the SCRF.