Diesel Particulate Filter Soot Load Estimation
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Solution Overview
Problem
Existing methods for determining diesel particulate filter (DPF) regeneration timing are inaccurate at low exhaust volume flows and during transient conditions due to sensor limitations, leading to potential overheating, reduced fuel economy, and increased component wear.
Innovation Solution
A system and method that combines pressure-based measurements with an estimated soot loading model, using recent accurate readings and operating conditions to continuously monitor particulate filter loading, ensuring more appropriate regeneration timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure-based measurements are used to monitor soot load, then regeneration timing can be controlled, but measurement accuracy deteriorates at low exhaust volume flows and during transient conditions
Solution Approach 1:
The patent introduces an intermediary soot load estimation model that mediates between pressure-based measurements and actual soot load. This model uses engine operating parameters (exhaust temperature, oxygen concentration, engine load) to calculate soot generation rates, providing a reliable estimate during transient conditions when pressure sensors are inaccurate. The intermediary model fills the gap between unreliable sensor data and required accurate monitoring.
Solution Approach 2:
The patent replaces the mechanical/physical pressure-based measurement system with a computational estimation system during transient conditions. Instead of relying on differential pressure sensors that fail at low flows, the system substitutes a mathematical model that calculates soot load based on engine operating parameters, effectively replacing the unreliable physical measurement mechanism with a computational one.
2Object-affected harmful factors
If regeneration is performed frequently to prevent overheating, then filter safety is improved, but fuel economy deteriorates due to energy consumption
Solution Approach 1:
The patent implements a feedback mechanism that continuously monitors soot load using both pressure measurements and the estimation model, then adjusts regeneration timing accordingly. The system compares the estimated soot load against threshold values and only triggers regeneration when necessary, creating a closed-loop control system that prevents both overheating and unnecessary regeneration cycles, thereby optimizing fuel economy.
Solution Approach 2:
The patent performs preliminary estimation of soot load using the estimation model during transient conditions before determining whether regeneration is needed. This preliminary action allows the system to predict future soot accumulation and plan regeneration timing optimally, avoiding both premature regeneration (wasting energy) and delayed regeneration (risking overheating).
3Duration of action of moving object
If pressure-based measurements are used continuously, then monitoring coverage is maintained, but accuracy deteriorates during transient conditions
Solution Approach 1:
The patent makes the monitoring system dynamic by switching between two different monitoring approaches based on operating conditions. During steady-state conditions, the system uses pressure-based measurements; during transient conditions, it switches to the estimation model. This dynamic adaptation allows the system to maintain both continuous monitoring coverage and high accuracy across all operating regimes.
Solution Approach 2:
The patent segments the monitoring function into two distinct components: pressure-based measurement for steady-state conditions and estimation model for transient conditions. By segmenting the monitoring task based on operational context, the system can optimize for accuracy during transients without sacrificing continuous monitoring coverage, as each segment excels at its designated operating regime.
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 provides more accurate and continuous monitoring of particulate filter loading, reducing the risk of overheating and improving fuel economy by optimizing regeneration timing, even under conditions where pressure-based measurements are inaccurate.
Implementation Method 1
The regeneration may be achieved by raising the temperature of the PF to a predetermined level to oxidize the accumulated particulate matter
Implementation Method 2
raising the temperature of the PF to a predetermined level
Data Source
AI summary
Methods for updating the PF soot load of an engine are provided herein. In one example, a soot storage estimate is based on processing operations that occur at different timings. The method can improve soot estimation during some conditions.