Variable Spray Angle Nozzle for SCR NOx Reduction
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Solution Overview
Problem
Current selective catalytic reduction (SCR) systems for internal combustion engines face challenges in efficiently varying reductant spray angles and dosing rates to effectively reduce NOx emissions, as existing systems lack precision in reductant deposition within exhaust aftertreatment systems.
Innovation Solution
A variable spray angle nozzle assembly with multiple reductant insertion ports, where the spray angle and dosing rate are controlled electronically to optimize reductant delivery, utilizing a reductant dosing controller that calculates the NOx conversion ratio and specifies the reductant delivery region and actuation period to direct the opening of specific ports, ensuring precise reductant deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional fixed spray angle nozzle is used, then the structure is simple, but the precision of reductant deposition and NOx reduction efficiency are insufficient
Solution Approach 1:
The patent applies the dynamics principle by making the spray angle adjustable rather than fixed. The nozzle is designed with multiple spray angles that can be selected based on operating conditions, allowing the system to adapt to different exhaust flow rates and NOx reduction requirements. This dynamic adjustment capability improves reductant deposition precision while managing the complexity through a modular angle selection mechanism rather than a fully continuous variable system.
Solution Approach 2:
The patent segments the nozzle into multiple discrete spray angle options rather than providing a fully continuous variable spray angle. Each spray angle is a distinct configuration that can be independently selected, which simplifies the control mechanism while still providing multiple precision levels for reductant deposition. This segmentation approach allows for easier manufacturing and control compared to a fully continuous variable system.
2Productivity
If the reductant dosing rate is increased to improve NOx reduction, then the NOx conversion efficiency improves, but the risk of reductant slip and unburned reductant increases
Solution Approach 1:
The patent applies parameter changes by varying the spray angle parameter to optimize reductant delivery. By adjusting the spray angle, the system can change the distribution pattern of reductant in the exhaust stream, allowing for better mixing and combustion at higher dosing rates. This parameter adjustment enables the system to increase NOx reduction efficiency while controlling harmful effects through optimized reductant placement and dispersion.
3Adaptability or versatility
If multiple spray angles are implemented to optimize reductant delivery, then the NOx reduction effectiveness improves, but the device complexity increases
Solution Approach 1:
The patent segments the spray angle capability into discrete, predefined options rather than providing a fully continuous variable system. This segmentation reduces the complexity of control mechanisms while still providing multiple adaptability levels. Each spray angle configuration is a distinct, manageable option that can be selected based on specific operating conditions, making the system versatile without requiring complex continuous adjustment mechanisms.
Data Source
AI summary
In an assembly and methods for NOx reductant dosing with variable spray angle nozzle, according to various embodiments, a reductant dosage is calculated. A reductant delivery region in an exhaust stream area of an aftertreatment system and an actuation period may be specified. Based at least on the reductant delivery region and the actuation period, the reductant insertion assembly may be placed in a state for reductant delivery such that one of a first array of reductant insertion ports and a second array of reductant insertion ports is in an open position. The shape of the variable spray angle nozzle may define different levels. Different arrays of reductant delivery ports may have varying operating characteristics, such as diameter, number of ports, actuation time, and/or reagent delivery angle and may be activated based on reductant flow pressure and/or reductant flow velocity.