Diesel Particulate Filter Soot Combustion via Exhaust Back-Pressure Control

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Solution Overview

Problem

Existing diesel engine systems with diesel particulate filters face complexity in forced regeneration strategies, particularly in maintaining exhaust gas temperature for soot combustion, which can be intrusive and require compatible vehicle operation.

Innovation Solution

Employing exhaust back-pressure control through a processor-based system that processes data on exhaust gas temperature, pressure drop, and mass flow to selectively increase back-pressure and initiate soot combustion in the diesel particulate filter, regardless of initial temperature, using an algorithm to determine optimal conditions for combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If forced regeneration strategy is implemented to combust soot trapped by DPF, then soot combustion efficiency is improved, but engine control system complexity increases

Engineering Contradiction:

Improvesoot combustion efficiencyVSAvoidengine control system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The system uses the engine's own exhaust back-pressure as the heating mechanism for soot combustion, eliminating the need for external heating systems or complex fuel injection control. The exhaust gas naturally heats the DPF when back-pressure is increased, allowing the system to regenerate itself using existing engine operations.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system controls the degree of back-pressure applied to the exhaust system to precisely regulate exhaust gas temperature. By adjusting the back-pressure parameter, the system can raise exhaust temperature to the required range for soot combustion (typically above 250°C) without needing complex thermal management systems.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If exhaust gas temperature is elevated to initiate soot combustion, then soot burning efficiency is improved, but driver operation transparency deteriorates

Engineering Contradiction:

Improvesoot burning efficiencyVSAvoiddriver operation transparency

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The back-pressure control is dynamically adjusted based on real-time monitoring of exhaust gas temperature and DPF soot load conditions. The system modulates the back-pressure application to achieve combustion only when conditions are appropriate, rather than applying constant back-pressure that would affect driver experience.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system continuously monitors exhaust gas temperature and DPF pressure differential to determine when soot combustion should be initiated. This feedback mechanism ensures that back-pressure is applied only when it will achieve the desired combustion effect, avoiding unnecessary interventions that would complicate driver operation.

Inventive Principle:

Principle #23Feedback

3Temperature

If back-pressure control device is operated to increase exhaust back-pressure, then exhaust gas temperature is elevated for soot combustion, but exhaust flow restriction increases

Engineering Contradiction:

Improveexhaust gas temperatureVSAvoidexhaust flow restriction

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The back-pressure control device operates periodically rather than continuously, applying back-pressure in controlled cycles to raise exhaust temperature for soot combustion. Between combustion events, the back-pressure is reduced to allow normal exhaust flow, minimizing the cumulative harmful effect of exhaust restriction on engine performance.

Inventive Principle:

Principle #19Periodic 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 allows for efficient soot combustion in diesel particulate filters without significantly complicating the engine control system, enabling effective retrofitting of existing vehicles and maintaining operational transparency to the driver.

Implementation Method 1

operating a device, regardless of exhaust gas temperature, that increases exhaust back-pressure on the engine sufficiently to cause elevation of the temperature of exhaust gas entering and passing through the diesel particulate filter to a temperature sufficient to initiate combustion of trapped soot

Methodology Applied

Scientific EffectCompression heating: Adiabatic Heating

Implementation Method 2

An exhaust system of a diesel engine that comprises a diesel particulate filter (DPF) is capable of physically trapping diesel particulate matter (DPM) in exhaust gas passing through the exhaust system from the engine

Methodology Applied

Scientific EffectPhysical trapping/filtration: Filter (physical)

Implementation Method 3

combustion of material trapped by the DPF... elevate the temperature of exhaust gas entering and passing through the diesel particulate filter to a temperature sufficient to initiate combustion of trapped soot

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS8434299B2Strategy employing exhaust back-pressure for burning soot trapped by a diesel particulate filter

Publication Date: 2013.05.07 INT ENGINE INTPROP CO LLC

AI summary

An exhaust system (16) of a diesel engine (10) has a diesel particulate filter (18) for treating exhaust gas. When trapped soot has accumulated to an extent that may affect performance of the filter, an engine control system (12) forces combustion of trapped soot by increasing exhaust back-pressure using a control device (20) such as a back-pressure control valve or vanes of a variable geometry turbocharger.