Multi-nozzle DEF Injection Platform for SCR Systems
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Solution Overview
Problem
Existing diesel exhaust systems face challenges in properly mixing diesel exhaust fluid (DEF) into the exhaust stream, leading to potential concentration issues that require downstream baffles for adequate dispersion, which complicates the reduction of NOx using SCR systems.
Innovation Solution
An injection mixing platform within the exhaust pipe featuring radially extending mixing blades with nozzles, statically mounted to the pipe's inner surface, ensures thorough mixing of DEF with the exhaust stream by imparting swirl and atomizing the DEF mist at the point of injection, eliminating the need for downstream mixing baffles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If DEF is injected into the exhaust stream using conventional single-point injection, then the injection system is simple, but the DEF mixing is insufficient requiring additional downstream baffles
Solution Approach 1:
The injection system is segmented into multiple nozzles distributed across the injection platform, with each nozzle injecting DEF at different locations. This segmentation allows simultaneous injection at multiple points, improving mixing efficiency while maintaining a relatively simple overall structure without requiring downstream baffles
Solution Approach 2:
The injection system transitions from single-point injection to multi-point distributed injection across a platform. This dimensional expansion from a single location to a distributed array of nozzles enables better DEF dispersion and mixing in the exhaust stream, eliminating the need for additional downstream mixing components
2Stability of the object's composition
If downstream baffles are added to improve DEF dispersion, then the DEF mixing is adequate, but the device complexity increases
Solution Approach 1:
The multi-nozzle injection platform performs preliminary mixing action at the point of injection by distributing DEF across multiple locations simultaneously. This preliminary distribution creates initial mixing zones that continue to blend as exhaust flows downstream, achieving adequate dispersion without requiring additional downstream baffles or mixing components
Solution Approach 2:
The invention extracts the mixing function from the downstream section and relocates it to the injection platform itself. By integrating multiple nozzles that create distributed injection patterns, the system performs the mixing action at the source, eliminating the need for separate downstream mixing devices
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 solution ensures efficient and uniform mixing of DEF with the exhaust stream at the point of injection, enhancing the effectiveness of SCR systems by preventing DEF concentration and reducing the need for additional mixing components, thereby improving NOx reduction efficiency.
Implementation Method 1
atomizing the DEF mist at the point of injection
Implementation Method 2
imparting swirl and atomizing the DEF mist
Data Source
AI summary
An injection apparatus includes an injection mixing platform located within an exhaust pipe; wherein the injection mixing platform includes two or more mixing blades extending radially from a common central hub, at least one of the mixing blades being coupled to a DEF inlet to receive DEF from an external tank, wherein each of the two or more mixing blades includes at least one nozzle to eject the DEF into an exhaust stream, the two or more mixing blades being statically mounted to an inner surface of the exhaust pipe.