Particle Filter Soot Load Estimation Using Exhaust Flow Thresholds
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Solution Overview
Problem
Existing methods for estimating soot load in particle filters are unreliable due to sensor accuracy issues and condensate effects, leading to non-optimal regeneration times that increase fuel consumption and vehicle backpressure.
Innovation Solution
A method that determines the optimal time for measuring differential pressure across the particle filter by ensuring high exhaust volume flow, filter temperature above condensation thresholds, and absence of condensate to provide accurate soot load estimation, minimizing errors from sensor inaccuracies and condensate-induced backpressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If differential pressure measurement is used to determine soot load in the particle filter, then regeneration timing can be controlled, but measurement accuracy deteriorates due to sensor errors and condensate interference
Solution Approach 1:
The system performs preliminary actions by heating the particle filter to a predetermined temperature before taking differential pressure measurements. This preliminary heating eliminates condensate interference and ensures accurate soot load estimation. The method also preliminarily determines exhaust volume flow to select optimal measurement timing points.
Solution Approach 2:
The invention changes the temperature parameter by heating the particle filter to a predetermined temperature before measurement. It also changes the exhaust volume flow parameter by selecting specific timing points when flow exceeds a threshold value. These parameter changes eliminate measurement errors and improve precision.
2Measurement precision
If regeneration is performed frequently to ensure clean particle filter, then soot load measurement accuracy improves, but fuel consumption increases
Solution Approach 1:
The system uses feedback by continuously monitoring differential pressure, exhaust volume flow, and particle filter temperature. Based on this feedback, it determines optimal measurement timing points and decides when regeneration is actually needed, avoiding unnecessary frequent regeneration and reducing fuel consumption.
Solution Approach 2:
The invention makes the measurement and regeneration process dynamic by adapting to real-time conditions. It selects measurement timing points based on instantaneous exhaust volume flow and temperature conditions, rather than using fixed periodic intervals, thereby optimizing fuel consumption.
3Extent of automation
If differential pressure sensor is used to monitor soot load, then regeneration control is enabled, but measurement reliability deteriorates due to condensate and temperature effects
Solution Approach 1:
The system changes the temperature parameter by heating the particle filter to a predetermined temperature before measurements. It also changes the exhaust volume flow parameter by selecting timing points when flow exceeds thresholds. These parameter changes eliminate condensate effects and improve measurement reliability for automated regeneration control.
Solution Approach 2:
The system performs preliminary heating of the particle filter and preliminary determination of exhaust volume flow conditions before taking measurements. This preliminary action ensures that measurements are taken under optimal conditions, improving reliability for automated control.
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 results in a robust and reliable soot load estimate that reduces fuel consumption by ensuring accurate regeneration timing and minimizing the impact of condensate and sensor errors, leading to improved vehicle performance and reduced fuel usage.
Implementation Method 1
Particle filters are used to capture these soot particles, and work in such a way that the exhaust flow is led through a filter structure whereby soot particles are captured from the passing exhaust flow and are stored in the particle filter.
Implementation Method 2
In active regeneration, fuel is added to the exhaust gases and is intended to burn up in an oxidation catalyst situated upstream from the particle filter. In active regeneration, carbon is converted by oxygen to carbon dioxide and water.
Implementation Method 3
This chemical reaction requires relatively high particle filter temperatures for desired reaction rates (filter emptying rates) to be achieved at all.
Implementation Method 4
a differential pressure across the particle filter, i.e. a pressure drop across the filter, is used to determine the soot load in the filter
Data Source
AI summary
A method and a system for estimation of a soot load in a particle filter in an exhaust cleaning system, which estimation involves using a pressure drop across said particle filter in order to determine the soot load. Measurement of the pressure drop across the particle filter and therefore the estimation have to take place at a time when an exhaust mass flow of the exhaust cleaning system exceeds a flow threshold value, the particle filter is substantially free from water and a temperature of the particle filter exceeds a first threshold value. The result is a robust estimate of the soot load in the particle filter.