DPF Loading Calculation Using Transient Condition Validation
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Solution Overview
Problem
Existing methods for calculating particulate loading in diesel particulate filters (DPFs) during transient engine operation conditions often introduce significant errors due to differing rates of pressure and flow changes, leading to premature or delayed regeneration.
Innovation Solution
A processor-based algorithm that calculates derivatives of pressure and flow rates over time, processes these derivatives to ensure compliance with defined relationships, and conditions the validity of particulate loading calculations to prevent errors during transient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If particulate loading is calculated during transient operating conditions, then regeneration timing can be determined more frequently, but significant errors are introduced due to differing rates of pressure and flow changes
Solution Approach 1:
The patent applies parameter changes by monitoring the rates of change of pressure and flow rate parameters during transient conditions. When the difference between these rates exceeds a threshold, the system switches from using real-time measurements to using windowed (averaged) measurements, thereby adapting the calculation method to current operating conditions and maintaining accuracy during transients
Solution Approach 2:
The system dynamically adjusts its calculation approach based on operating conditions. By detecting transient conditions through rate-of-change analysis and switching between different calculation methods (real-time vs. windowed), the system maintains measurement precision across varying operational states while still enabling frequent regeneration assessments
2Reliability
If regeneration is forced based on inaccurate loading calculations during transients, then particulate burning can be initiated, but regeneration may occur prematurely or be delayed due to calculation errors
Solution Approach 1:
The system employs feedback by continuously monitoring pressure and flow rate measurements and their rates of change. This feedback mechanism detects transient conditions and triggers appropriate response actions (switching to windowed calculations or postponing regeneration decisions), ensuring that regeneration is initiated only when accurate loading data is available, thereby preventing premature or delayed regeneration
Solution Approach 2:
The patent applies preliminary anti-action by detecting transient conditions before they corrupt the particulate loading calculation. By identifying when pressure and flow rate are changing at significantly different rates, the system preemptively switches to alternative calculation methods or postpones regeneration decisions, preventing the harmful effect of inaccurate calculations on regeneration timing
Data Source
AI summary
An algorithm (26) in an engine control system (14) develops data indicative of pressure across a DPF (20) as a function of time and data indicative of flow rate through the DPF as a function of time, calculates derivatives (32, 30) (38, 36) with respect to time of the data, processes the derivatives (44, 42, 50, 48, 56, 54, 58) to confirm validity of a calculation of particulate loading of the DPF (load_pf) when a result of processing the derivatives discloses the absence of transient conditions in the DPF that would prevent the calculation from being valid and to not confirm validity of a calculation of particulate loading of the DPF when a result of processing the derivatives discloses the presence of transient conditions in the DPF that would prevent the calculation from being valid.