DPF Delta-Pressure Soot Estimation for Low-Restriction Filters

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Solution Overview

Problem

Existing methods for regenerating diesel particulate filters are fuel and energy intensive, leading to reduced fuel economy and increased emissions, and struggle to accurately estimate soot levels, especially during low exhaust flow cycles, which can result in premature filter failure and decreased efficiency.

Innovation Solution

A system using a delta pressure sensor to estimate soot levels in diesel particulate filters, which increases exhaust temperature and volumetric flow to re-evaluate soot accumulation before initiating regeneration, allowing for more accurate soot estimation and reducing unnecessary regeneration events, thereby improving fuel economy and extending filter life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a low restriction diesel particulate filter is used, then fuel economy and exhaust flow efficiency are improved, but soot estimation accuracy deteriorates leading to premature filter failure

Engineering Contradiction:

Improvefuel economyVSAvoidsoot estimation accuracy

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

The system performs a preliminary validation step by temporarily increasing exhaust temperature and volumetric flow to re-evaluate soot accumulation levels. This preliminary action allows accurate soot estimation under improved flow conditions before committing to regeneration, resolving the contradiction between using low restriction filters and maintaining estimation accuracy

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system changes operating parameters by increasing exhaust temperature and volumetric flow during the validation phase. This parameter change enables the delta pressure sensor to provide accurate soot readings under conditions where flow is sufficient for reliable measurement, while still allowing the use of low restriction filters during normal operation

Inventive Principle:

Principle #35Parameter changes

2Reliability

If active regeneration is initiated frequently to prevent filter failure, then filter reliability is improved, but fuel consumption increases

Engineering Contradiction:

Improvefilter reliabilityVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system uses feedback from the delta pressure sensor readings taken under increased volumetric flow conditions to accurately determine actual soot accumulation levels. This feedback mechanism prevents premature regeneration by providing reliable data on filter status, allowing regeneration to occur only when truly necessary, thus improving reliability without excessive fuel consumption

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The validation step serves as a preliminary action that confirms the need for regeneration before it is initiated. By re-evaluating soot levels under improved flow conditions, the system ensures that regeneration is only performed when actually required, avoiding unnecessary fuel consumption while maintaining filter reliability

Inventive Principle:

Principle #10Preliminary action

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 soot estimation and reduces unnecessary regeneration, leading to improved fuel economy, lower emissions, and extended filter lifespan without increasing NO2 emissions, allowing for the use of lower restriction filters while maintaining efficient diesel particulate filter operation.

Implementation Method 1

A delta pressure sensor is used to estimate soot levels in diesel particulate filters

Methodology Applied

Scientific EffectDelta pressure measurement: Pressure Drop

Implementation Method 2

cause the unburned fuel to reach the diesel oxidation catalyst and be burned off in a catalyzed reaction... to raise the exhaust temperature sufficiently to initiate regeneration

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 3

be burned off in a catalyzed reaction using the diesel oxidation catalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 4

regeneration by burning off (i.e., oxidizing) the particulates that accumulate on the filters

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11867112B1Logic for improved delta pressure based soot estimation on low restriction particulate filters

Publication Date: 2024.01.09 INT ENGINE INTPROP CO LLC

AI summary

Vehicle exhaust system uses delta pressure based estimation of accumulated soot within a diesel particulate filter. The exhaust system has a diesel oxidation catalyst and a diesel particulate filter. A fuel injector is connected upstream from the diesel oxidation catalyst and the diesel particulate filter. A delta pressure sensor measures difference in pressure at inlet and outlet of the diesel particulate filter. A controller determines when to regenerate the diesel particulate filter based on an estimated amount of soot. The controller, in a first regeneration mode, causes the fuel injector to inject fuel at a first rate into the exhaust stream, and to re-evaluate amount of soot accumulated within the diesel particulate filter under increased volumetric flow. The controller, in a second regeneration mode, causes the fuel injector to inject fuel at a second rate into the exhaust stream in order to combust soot trapped in the diesel particulate filter.