Particulate Trap Regeneration via Reverse Pressure Drop
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Solution Overview
Problem
Existing particulate trap systems face challenges in efficiently removing soot and ash cakes without excessive temperature requirements, noble metal catalytic coatings, and disruptive maintenance, especially in achieving stringent NOx emission standards while minimizing engine backpressure and wear.
Innovation Solution
A system utilizing a valving mechanism and reversing apparatus to create an instantaneous reverse pressure drop across the particulate trap, using filtered exhaust gas to dislodge and remove soot/ash deposits, and a control system that operates independently of engine controls, leveraging diesel exhaust brake pressures for regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If burning particulate in the trap is used for regeneration, then soot removal is achieved, but excessive temperatures and expensive noble metal catalytic coatings are required
Solution Approach 1:
The patent replaces thermal regeneration (burning soot) with a mechanical regeneration approach using reverse pressure drop pulses. The system uses a valving mechanism to create instantaneous reverse pressure drops that dislodge particulate from the trap walls, eliminating the need for high temperatures and catalytic coatings.
Solution Approach 2:
The patent employs pneumatic principles by using filtered exhaust gas flow to create reverse pressure drops across the trap. The valving mechanism controls gas flow to generate pressure pulses that mechanically remove particulate, substituting thermal processes with pressure-driven mechanical removal.
2Productivity
If high reverse pressure drop is applied for regeneration, then soot dislodging is effective, but component wear and reliability issues occur
Solution Approach 1:
The patent uses periodic reverse pressure drop pulses rather than continuous high pressure. The valving mechanism creates instantaneous pressure drops at specific intervals, allowing the trap to be regenerated effectively while minimizing cumulative stress and wear on components compared to continuous operation.
Solution Approach 2:
The system dynamically adjusts the regeneration process by controlling when and how strongly reverse pressure drops are applied. The valving mechanism can modulate pressure drop magnitude and duration based on trap loading conditions, optimizing regeneration effectiveness while protecting components from excessive wear.
3Force
If duct/rotor is stationary during high reverse pressure drop, then pressure induced force on trap face is high, but wear occurs during rotation when pressure is zero
Solution Approach 1:
The patent makes the duct/rotor position dynamic by rotating it to align with contaminated passages during regeneration. The rotor can rotate when reverse pressure is present to maximize contact with soot deposits, and stop when pressure is applied to avoid wear, creating an adaptive system that optimizes both cleaning effectiveness and component protection.
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
Effectively regenerates particulate traps with reduced wear and maintenance, achieving high trapping efficiency while minimizing engine backpressure and NOx emission challenges, and is adaptable to various engine types and sizes.
Implementation Method 1
causing a reversed flow of the filtered exhaust gas to flow back through the porous walls to a point downstream of the trap to remove the dislodged particulate from the trap
Implementation Method 2
a wall-flow particulate trap having a plurality of porous walls for filtering engine exhaust and removing particulates therefrom to form a particulate cake on the porous walls
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A system for regenerating a particulate trap in an exhaust system of an internal combustion engine and including a wall-flow particulate trap having a plurality of porous walls for filtering engine exhaust and removing particulates therefrom to form a particulate cake on the porous walls, a valving mechanism downstream of said trap for periodically creating a reverse pressure throughout said trap, a reversing apparatus operative after the reverse pressure is created for periodically creating a substantially instantaneous reverse pressure drop across the porous walls of said trap to dislodge accumulated particulate cake and causing the filtered exhaust gas to flow back through the porous walls to remove the dislodged particulate from said trap, and controls for starting and stopping a regeneration cycle.