Diesel Particulate Filter Regeneration Temperature Control

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Solution Overview

Problem

Existing exhaust gas purifying systems face issues with cell melting and inefficient combustion of particulate matter in Diesel Particulate Filters (DPFs) due to excessive combustion temperature during forced regeneration, which is not adequately addressed by existing methods.

Innovation Solution

An exhaust gas purifying system that includes a filter, differential pressure detector, flow rate detector, and a regeneration temperature setting unit, which adjusts the regeneration temperature based on detected differential pressure and flow rate to prevent cell melting and ensure efficient combustion of particulate matter, by setting a lower initial temperature and increasing to a higher temperature only when differential pressure falls below a threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If forced regeneration is performed when PM deposition amount exceeds a predetermined reference value, then particulate matters are combusted to restore filter function, but combustion temperature becomes excessively high and cells may be melted

Engineering Contradiction:

Improvefilter function restorationVSAvoidcombustion temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The system performs preliminary combustion at a first (lower) temperature before performing combustion at a second (higher) temperature. This preliminary action reduces the PM deposition amount partially, so that subsequent combustion at higher temperature does not cause cell melting while still achieving complete regeneration

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The regeneration process is divided into multiple periodic stages: first combustion at a lower temperature, then second combustion at a higher temperature. This periodic approach allows controlled temperature management throughout the regeneration process, preventing excessive temperature while ensuring complete PM removal

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If differential pressure is used to estimate PM deposition amount, then PM amount can be monitored, but cell clogging causes false high readings and premature forced regeneration

Engineering Contradiction:

ImprovePM deposition amount estimationVSAvoidforced regeneration timing accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system continuously monitors differential pressure and uses it as feedback to control the regeneration process. By adjusting regeneration temperature based on differential pressure readings, the system can distinguish between actual PM deposition and cell clogging effects, enabling accurate timing of forced regeneration

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system changes the regeneration temperature parameter based on differential pressure conditions. When differential pressure is high, the system applies lower temperature first; when differential pressure decreases to a threshold, it switches to higher temperature combustion. This dynamic parameter adjustment resolves the contradiction between monitoring accuracy and regeneration timing reliability

Inventive Principle:

Principle #35Parameter changes

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

Prevents cell melting and ensures efficient combustion of particulate matter by controlling the regeneration temperature, effectively addressing the limitations of existing systems.

Implementation Method 1

a differential pressure detector configured to detect a differential pressure between an inlet and outlet of the filter

Methodology Applied

Scientific EffectDifferential pressure detection: Pressure Drop

Implementation Method 2

a flow rate detector configured to detect a flow rate of the exhaust gas flowing in the filter

Methodology Applied

Scientific EffectFlow rate detection:

Implementation Method 3

an external dosing in which fuel is injected in an upstream of the DPF or an internal dosing in which the fuel is injected into a cylinder of the engine is performed, thereby forcibly combusting the deposited PM

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS10422265B2Exhaust gas purifying system and exhaust gas purifying method

Publication Date: 2019.09.24 KOMATSU LTD

AI summary

An exhaust gas purifying system includes a differential pressure detector that detects a differential pressure between an inlet/outlet of a filter, a flow rate detector that detects a flow rate of exhaust gas in the filter, a differential based-deposition-amount calculator that calculates a differential-based deposition amount of particulate matters in the filter based on detection results of the differential pressure detector and the flow rate detector, a regeneration temperature setting unit that sets a regeneration processing temperature of the filter based on the calculated differential-based deposition amount, and a regeneration processing unit that performs a regeneration processing of the filter based on the set regeneration processing temperature. The regeneration temperature setting unit sets a first regeneration processing temperature at a start of the regeneration processing and a second regeneration processing temperature higher than the first regeneration processing temperature when the differential-based deposition amount falls at or below a predetermined threshold.