Urea Injector Nozzle Spray Head Alignment
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Solution Overview
Problem
Current engine after-treatment systems for reducing NOx emissions, such as SCR systems, face inefficiencies in delivering reducing agents like urea into exhaust gas streams, particularly in aligning spray patterns to optimize NOx reduction.
Innovation Solution
The development of an injector nozzle assembly with a spray head featuring multiple orifices aligned in a horizontal plane, oriented parallel to the exhaust gas flow direction, and angled relative to the center axis, ensuring efficient delivery of the reducing agent into the exhaust gas stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the spray head orifices are oriented perpendicular to the exhaust gas flow direction (conventional design), then the reducing agent is delivered into the exhaust stream, but the spray pattern alignment is poor and agent deposition occurs on the pipe wall
Solution Approach 1:
The spray head orifices are oriented at an asymmetric angle (10-45 degrees) relative to the exhaust gas flow direction, rather than being perpendicular to it. This asymmetric orientation allows the spray pattern to align with the exhaust gas flow, preventing agent deposition on pipe walls while improving mixing efficiency
Solution Approach 2:
The invention introduces angular orientation as a new dimension for orifice configuration. By tilting the orifices at specific angles relative to the exhaust gas flow direction, the system transitions from a conventional perpendicular orientation to an optimized angular orientation, improving spray pattern alignment without increasing system complexity
2Productivity
If the reducing agent is injected directly into the exhaust stream without optimized spray alignment, then the injection process is simple, but the conversion of urea into ammonia is inefficient
Solution Approach 1:
The invention optimizes the angular parameter of the orifices (10-45 degrees relative to exhaust gas flow direction) to improve conversion efficiency. This parameter change enhances the spray pattern alignment and urea-to-ammonia conversion without requiring complex additional components
Solution Approach 2:
The spray head features localized quality variations through differently oriented orifices. The orifices are positioned and angled to create specific spray patterns in different regions, with some orifices optimized for direct injection and others for enhanced mixing, improving overall conversion efficiency
3Quantity of substance
If multiple orifices are added to the spray head to improve spray pattern distribution, then the reducing agent coverage is enhanced, but the device complexity increases
Solution Approach 1:
The spray head is segmented into multiple orifices (3-6 openings) distributed around the central axis. Each orifice is oriented at specific angles to cover different regions of the exhaust stream, providing comprehensive reducing agent distribution while maintaining a relatively simple integrated spray head structure
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 design enhances the spray pattern alignment within the exhaust gas flow path, improving the conversion of urea into ammonia for effective NOx reduction, meeting stricter emissions standards while preventing agent deposition and ensuring efficient evaporation.
Implementation Method 1
spraying the reducing agent that exits an outlet of the injector pipe through a spray head having three to four orifices
Implementation Method 2
ensuring efficient delivery of the reducing agent into the exhaust gas stream... ensuring efficient evaporation
Data Source
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AI summary
An injector nozzle assembly for delivering a reducing agent fluid stream into an exhaust gas stream comprises a connector having an inlet for fluidly connecting to a reducing agent fluid source. The assembly further includes a cap that is connected to a nozzle body having a frustoconical portion. The assembly also includes an injector pipe having a length along an axis and passing through an opening in the cap into and through an at least partially hollow internal volume of the nozzle body. The injector pipe has an inlet fluidly connected to the connector and an outlet fluidly connected to a spray head. The spray head includes three to four substantially radial injection orifices. The injection orifices on the spray head are substantially aligned in a horizontal plane, and only oriented generally parallel to a flow direction of the exhaust gas stream.