Particulate Filter Regeneration Control via Oxygen Modulation

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Solution Overview

Problem

Conventional exhaust gas aftertreatment systems for internal combustion engines face challenges in controlling uncontrolled regeneration of particulate filters, which can lead to excessive burning of particulate matter, especially when engine speed drops to idle speeds during active regeneration processes.

Innovation Solution

The method involves reducing the oxygen concentration of exhaust gas supplied to the particulate filter by controlling the exhaust gas recirculation valve, adjusting the air-to-fuel ratio, and using an oxidation catalyst to consume oxygen, thereby inhibiting uncontrolled regeneration by modulating the oxygen levels within target ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If active regeneration is performed to remove collected particulate matter, then the particulate filter is cleaned, but uncontrolled regeneration occurs causing excessive burning of particulate matter

Engineering Contradiction:

Improveparticulate filter cleaningVSAvoidexcessive burning of particulate matter

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system changes the oxygen concentration parameter of the exhaust gas to control the regeneration process. By reducing oxygen concentration to a lower range during active regeneration, the system prevents uncontrolled regeneration while still enabling complete combustion of particulate matter, thus resolving the contradiction between effective cleaning and preventing excessive burning

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system uses oxygen concentration sensors to continuously monitor the exhaust gas and adjusts the EGR valve position accordingly. This feedback mechanism ensures that oxygen concentration remains within the optimal range for controlled regeneration, preventing both incomplete burning and uncontrolled regeneration

Inventive Principle:

Principle #23Feedback

2Ease of operation

If engine speed drops to idle during active regeneration, then the engine operates at low speed, but uncontrolled regeneration is triggered

Engineering Contradiction:

Improveengine idle operationVSAvoidcontrolled regeneration

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system takes preliminary action by detecting the condition of engine speed dropping to idle during active regeneration and proactively adjusting the EGR valve to reduce oxygen concentration before uncontrolled regeneration can occur. This preventive measure maintains controlled regeneration even during idle operation

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system dynamically adjusts the EGR valve position based on real-time engine operating conditions. When engine speed drops to idle during regeneration, the system automatically modifies oxygen concentration levels to maintain optimal regeneration conditions, preventing uncontrolled regeneration while adapting to changing engine operations

Inventive Principle:

Principle #15Dynamics

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 effectively prevents uncontrolled regeneration of particulate filters by maintaining optimal oxygen concentrations, ensuring controlled burning of particulate matter and extending filter lifespan.

Implementation Method 1

using an oxidation catalyst to consume oxygen

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

controlling the exhaust gas recirculation valve to increase the concentration of exhaust gas in the intake air

Methodology Applied

Scientific EffectGas recirculation:

Implementation Method 3

a particulate filter that collects particulate matter, e.g., soot, present in the exhaust gas

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Implementation Method 4

the temperature of exhaust gas entering a particulate filter is actively increased to a temperature range sufficient to burn the collected particulate matter

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS7631492B2System and method for inhibiting uncontrolled regeneration of a particulate filter for an internal combustion engine

Publication Date: 2009.12.15 CUMMINS INC

AI summary

Inhibiting uncontrolled regeneration of a particulate filter fluidly coupled to an exhaust manifold of an internal combustion engine may comprise reducing an oxygen concentration of exhaust gas supplied to the particulate filter if active regeneration of the particulate filter is in progress and rotational speed of the engine speed thereafter drops to an idle speed range from an elevated rotational speed that is greater than the idle speed range. Reducing the oxygen concentration of the exhaust gas supplied to the particulate filter may include any one or combination of reducing the oxygen concentration of intake air supplied to the intake manifold, reducing the air portion of the air-to-fuel ratio of the air-fuel mixture supplied to the engine and removing oxygen from the exhaust gas supplied to the particulate filter.