Particulate Filter Regeneration Using Exhaust-Temperature-Dependent Heating

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Solution Overview

Problem

Existing methods for thermally regenerating exhaust aftertreatment systems in internal combustion engines, particularly particulate filters, result in high fuel consumption and pollutant emissions due to deliberate reduction in engine efficiency to increase exhaust gas temperature, leading to issues like oil dilution and short lubricant change intervals.

Innovation Solution

An electric heating device is used to regenerate the exhaust aftertreatment system based on soot load and exhaust gas temperature, allowing regeneration at optimal engine conditions without increasing exhaust gas temperature, thereby minimizing energy consumption and emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the internal combustion engine operates at reduced efficiency to increase exhaust gas temperature for thermal regeneration, then the exhaust gas temperature increases, but fuel consumption increases

Engineering Contradiction:
Improveexhaust gas temperatureVSAvoidfuel consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical approach of deliberately reducing engine efficiency to increase exhaust gas temperature with an electrical heating device. This substitution allows the engine to operate at optimal efficiency while the heating device provides the necessary thermal energy for particulate filter regeneration, thereby resolving the contradiction between achieving high exhaust gas temperature and maintaining low fuel consumption.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an electrical heating device as an intermediary between the engine and the particulate filter. This intermediary component provides the required heat for regeneration without requiring the engine to operate inefficiently, thus decoupling the temperature requirement from fuel consumption penalties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If the internal combustion engine operates to generate high exhaust gas temperature, then thermal regeneration is achieved, but pollutant emissions increase

Engineering Contradiction:
Improveexhaust gas temperatureVSAvoidpollutant emissions
Core Design Contradiction:
TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent substitutes the mechanical method of generating high exhaust gas temperature through inefficient engine operation with an electrical heating device. This replacement enables thermal regeneration to proceed while the engine maintains efficient combustion, thereby reducing the generation of harmful pollutants such as unburned hydrocarbons and carbon monoxide.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If the internal combustion engine operates to generate high exhaust gas temperature, then thermal regeneration is achieved, but oil dilution increases

Engineering Contradiction:
Improveexhaust gas temperatureVSAvoidlubricant quality
Core Design Contradiction:
TemperatureVSLoss of substance

Solution Approach 1:

The patent replaces the approach of deliberately increasing exhaust gas temperature through engine operation adjustments with an electrical heating device. This substitution prevents fuel components from being introduced into the lubricant, thereby avoiding oil dilution and extending lubricant service life, while still achieving the necessary temperature for particulate filter regeneration.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If the heating device is operated to regenerate the exhaust aftertreatment system, then regeneration is achieved, but energy consumption increases

Engineering Contradiction:
Improvesystem functionalityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements a control strategy that monitors exhaust gas temperature and adjusts the operation of the heating device accordingly. By activating the heating device only when exhaust gas temperature falls within specific ranges and the particulate filter reaches certain loading thresholds, the system achieves necessary regeneration while minimizing energy consumption compared to continuous or indiscriminate heating operation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies heating locally and selectively based on the actual state of the particulate filter and exhaust gas conditions. The control unit determines optimal regeneration timing by monitoring local parameters such as soot load and exhaust temperature, activating the heating device only when and where needed, thereby reducing overall energy consumption while maintaining system functionality.

Inventive Principle:
Principle #3Local quality

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 reduces fuel consumption and emissions by optimizing regeneration timing and power usage, maintaining system functionality while avoiding common inefficiencies and drawbacks of in-engine measures.

Implementation Method 1

An electric heating device (11) associated with the exhaust aftertreatment device (10) can be operated temporarily and as needed in order to reach a temperature that is sufficient for the regeneration of the exhaust aftertreatment device (10)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a particulate filter, which serves to reduce particles in exhaust gas produced during combustion processes

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP4060168B1Exhaust gas temperature dependent regeneration of a particulate filter using a heater
Publication Date: 2026.03.04 VOLKSWAGEN AG
  • EP4060168B1 patent drawingFigure 1

AI summary

Method for operating an internal combustion engine comprising an internal combustion engine (1) and an exhaust system (8) for removing exhaust gas from the internal combustion engine (1), wherein a thermally regenerable exhaust aftertreatment device (10) is integrated into the exhaust system (8), to which an electric heating device (11) is assigned, wherein the exhaust aftertreatment device (10) is heated by means of the heating device (11) in order to reach a temperature sufficient for the regeneration of the exhaust aftertreatment device (10), wherein the heating device (11) is operated when the loading state of the exhaust aftertreatment device (10) is above a first, relatively high loading limit and the internal combustion engine (1) produces exhaust gas with an exhaust gas temperature that lies within a first, relatively low temperature range, and also when the loading state of the exhaust aftertreatment device (10) is above a second,relatively low loading limit and the internal combustion engine (1) produces exhaust gas with an exhaust gas temperature that lies within a second, relatively high temperature range.