Nested Reductant Delivery Tubes for Compact NOx Mixing
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Solution Overview
Problem
Internal combustion engines emit nitrogen oxide (NOx) compounds, necessitating a reductant delivery system to convert NOx into non-NOx emissions, but existing systems face challenges in minimizing space claim due to limited physical space availability.
Innovation Solution
A reductant delivery system with an inlet body, outlet body, and nested transfer tubes that enhance swirl and mixing length without increasing space claim, utilizing a decomposition chamber and dosing module to convert reductant into ammonia, which is then injected upstream of the SCR catalyst member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If conventional reductant delivery systems are used, then NOx conversion function is provided, but space claim is excessive due to limited physical space availability
Solution Approach 1:
The patent implements nested transfer tubes where an inner transfer tube is positioned within an outer transfer tube, creating a compact concentric structure. This nesting arrangement allows the system to maintain sufficient mixing length and swirl generation for effective NOx conversion while significantly reducing the overall volume and space claim of the delivery system.
Solution Approach 2:
The patent utilizes a three-dimensional concentric arrangement with multiple transfer tubes operating in different radial dimensions. The inner and outer transfer tubes create multiple flow paths simultaneously, enabling enhanced mixing and swirl generation within a compact volume by exploiting spatial dimensionality rather than extending linearly in one direction.
2Manufacturing precision
If mixing length is increased to improve mixing uniformity, then NOx conversion efficiency improves, but space claim increases
Solution Approach 1:
The nested transfer tube structure enables extended mixing length within reduced space by creating concentric flow paths. The inner tube provides a central flow path while the annular space between inner and outer tubes provides additional mixing length, achieving high mixing uniformity without proportionally increasing overall system volume.
Solution Approach 2:
The patent employs curved and spiral transfer tube configurations that generate rotational flow and swirl. These curved paths increase the effective mixing length and enhance mixing uniformity through centrifugal forces and flow rotation, while the compact curved geometry occupies less linear space than straight equivalent-length tubes.
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 reduces NOx emissions by increasing mixing uniformity and reducing space requirements, allowing for scalable applications across various internal combustion engines.
Implementation Method 1
nested transfer tubes that enhance swirl and mixing length
Implementation Method 2
enhance swirl and mixing length
Implementation Method 3
utilizing a decomposition chamber and dosing module to convert reductant into ammonia
Implementation Method 4
injected upstream of the SCR catalyst member
Data Source
AI summary
A reductant delivery system includes: an inlet body including: an inlet body coupler surrounding an inlet body inlet that is configured to receive exhaust gas, an inlet body outer transfer shell coupled to the inlet body coupler, the inlet body outer transfer shell including: an inlet body outer transfer shell inner surface, and an inlet body outer transfer shell outlet extending through the inlet body outer transfer shell inner surface, an inlet body outer mounting shell coupled to the inlet body coupler and the inlet body outer transfer shell, the inlet body outer mounting shell and the inlet body outer transfer shell defining an inlet body cavity, the inlet body outer mounting shell; an outlet body comprising: an outlet body coupler, and an outlet body shell; and an outer transfer tube.