Particulate Filter Protection via Depollution Liquid Injection

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Solution Overview

Problem

Internal combustion engine particulate filters face the risk of uncontrolled temperature rise during regeneration, especially at idle conditions, due to increased oxygen and reduced exhaust gas flow, leading to potential damage from excessive soot combustion.

Innovation Solution

A method that estimates the soot mass flow rate during regeneration and injects a depollution liquid, such as a mixture of water and urea, into the exhaust line upstream of the particulate filter to control temperature by consuming excess energy and reducing the risk of overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the engine idles during regeneration to allow soot combustion, then the combustion rate increases and regeneration is accelerated, but the exhaust gas flow rate decreases and oxygen increases, causing uncontrolled temperature rise that can damage the particulate filter

Engineering Contradiction:

Improveregeneration speedVSAvoidtemperature rise

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary substance (water or water-based solution) injected into the exhaust line upstream of the particulate filter. This intermediary absorbs excess heat through evaporation, mediating between the intense soot combustion and the filter structure, preventing direct thermal damage while allowing regeneration to proceed.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent exploits the phase transition of water from liquid to vapor. The injected water undergoes endothermic evaporation in the high-temperature exhaust gases, absorbing excess thermal energy and preventing uncontrolled temperature rise in the particulate filter during idle regeneration.

Inventive Principle:

Principle #36Phase transitions

2Temperature

If post-injections are used to raise exhaust temperature for regeneration, then soot combustion is promoted, but excessive energy remains in the filter causing temperature to exceed safety limits

Engineering Contradiction:

Improveexhaust gas temperatureVSAvoidoverheating

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the thermal parameters of the exhaust system by introducing a cooling agent (water) that modifies the temperature profile. The water injection alters the energy balance, absorbing excess heat and maintaining the exhaust temperature within safe operating limits for the particulate filter.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful excess thermal energy into a beneficial cooling effect. The water injected into the exhaust line absorbs the surplus heat that would otherwise damage the filter, transforming the harmful overheating condition into a controlled thermal process that protects the filter while maintaining regeneration effectiveness.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 method effectively limits the maximum temperature of the particulate filter during runaway soot combustion at idle, reducing the risk of damage and maintaining filter integrity by using the endothermic evaporation reaction of the depollution liquid.

Implementation Method 1

injecting a depollution liquid, such as a mixture of water and urea, into the exhaust line upstream of the particulate filter to control temperature by consuming excess energy and reducing the risk of overheating

Methodology Applied

Scientific EffectEndothermic evaporation: Endothermic Reaction

Implementation Method 2

using the endothermic evaporation reaction of the depollution liquid

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3565959B1A method of protecting a particulate filter of an internal combustion engine during regeneration

Publication Date: 2020.11.04 PSA AUTOMOBILES SA

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AI summary

The invention relates mainly to a method for protecting a particle filter (51) in an exhaust line (1) of an internal combustion engine (2), in particular of a motor vehicle, including a selective catalytic reduction system and a particle filter (51), characterised in that said method includes: a step of estimating a mass flow of soot burned in said particle filter (51) during a regeneration of said particle filter (51); a step of comparing said estimated mass flow of burnt soot with a predetermined mass flow threshold; and, if said estimated mass flow of burnt soot is higher than said predetermined mass flow threshold, said method includes a step of injecting a pollutant-removal liquid into said exhaust line (1) upstream from said particle filter (51).