Cold Flame Gas Particle Filter Regeneration for Diesel Exhaust
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Solution Overview
Problem
Particle filters in diesel engines running on heavy fuel oil face challenges during regeneration due to the presence of salts and metal compounds, which can cause permanent damage when heated, and NOx removal is difficult under oxidizing conditions typical of compression ignition engines.
Innovation Solution
A particle filter apparatus and engine exhaust system utilizing a cold flame gas, generated by partially oxidizing fuel in preheated air, to remove soot deposits and regenerate particle filters, while controlling the flow of exhaust and cold flame gas to prevent damage and facilitate NOx reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional regeneration method (heating exhaust gas to above 800°C) is used to remove soot deposits, then soot removal efficiency is improved, but the filter is damaged by salts and metal compounds in the exhaust gas
Solution Approach 1:
The invention changes the temperature parameter from above 800°C to a lower temperature range (400-600°C) and introduces a reducing atmosphere (CO and HC gases) during regeneration. This parameter change allows effective soot removal while preventing filter damage from salt and metal compound melting that occurs at higher temperatures.
Solution Approach 2:
The invention introduces intermediary substances (CO and HC gases from fuel injection) that act as reducing agents during the regeneration process. These intermediaries create a reducing atmosphere that enables soot removal at lower temperatures without causing filter damage, mediating between the soot removal need and filter protection.
2Object-generated harmful factors
If EGR (exhaust gas recirculation) is used to reduce NOx emissions, then NOx removal is improved, but particulates mix with lubricating oil causing premature engine wear
Solution Approach 1:
The invention segments the exhaust gas flow into two separate paths: one for clean exhaust gas and another for EGR recirculation. The particle filter is placed only in the clean exhaust path, allowing NOx reduction through EGR while preventing particulate contamination of the lubricating oil, thus resolving the contradiction between NOx removal and engine wear prevention.
3Object-generated harmful factors
If particle filter is used to remove particulates from exhaust gas, then particulate removal is improved, but filter becomes blocked and needs regeneration
Solution Approach 1:
The invention enables continuous operation by implementing a dual-filter system where one filter is always available for clean exhaust gas while the other undergoes regeneration. The cold flame regeneration technology allows efficient soot removal without filter damage, ensuring continuous productive operation of the particle removal system.
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
The system effectively extends the life of particle filters by removing soot deposits and reducing NOx emissions without causing filter damage, enabling continuous operation of diesel engines on heavy fuel oil.
Implementation Method 1
the fuel is partially oxidized in preheated air to form a cold flame gas
Implementation Method 2
The cold flame is a phenomenon which has so far not received too much attention. In a cold flame the fuel is partially oxidized in preheated air and the temperature is kept constant at about 450° C.
Implementation Method 3
The reason for this has not been established yet, but is thought to be due to free radicals that are present in the cold flame gas, i.e. the partially oxidized, gaseous fuel.
Implementation Method 4
Incomplete combustion products (HC and CO) can be removed by an oxidation catalyst.
Implementation Method 5
The means for preheating the air may be a heat exchanger in which the heat of the exhaust gas warms up the air.
Data Source
AI summary
Engine exhaust system for an internal combustion engine, the engine exhaust system comprising an exhaust conduit (14) connected to an engine (30), an exhaust gas return conduit (32,33) such that at least a part of the exhaust gas can be returned to the engine. The exhaust gas return conduit, at least along a part of its length, is formed with at least two flow paths (48,49). The engine exhaust system further comprises a particle filter arranged in each of the at least two flow paths and at least one cold flame vaporizer (11) in which fuel is partially oxidized in preheated air to form a cold flame gas. The at least one cold flame vaporizer is arranged in fluid communication with all the flow paths such that the cold flame gas can flow through the particle filters, whereby the cold flame gas can be used to regenerate the particle filter in at least one of the exhaust flow paths while, simultaneously, exhaust gas can flow through the other exhaust flow path or exhaust flow paths. A method for the cleaning of a particle filter is also provided.