Movable Exhaust Probe for SCR Uniformity Mapping
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Solution Overview
Problem
Current SCR systems and aftertreatment technologies face challenges in efficiently determining the uniformity of reductant distribution across catalyst surfaces, leading to variability in emissions control, which requires larger catalysts and increased design efforts, and existing testing methods are time-consuming and inefficient.
Innovation Solution
A system with movable exhaust probes and linear actuators that allow for comprehensive mapping of gaseous species across the catalyst face without disrupting exhaust flow, enabling rapid data collection and improved design optimization of aftertreatment systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional testing rigs are used to determine uniformity of exhaust gas constituents, then measurement accuracy is improved, but testing time and preparation requirements increase significantly
Solution Approach 1:
The patent employs a movable probe assembly that can dynamically position sampling points across the exhaust gas flow cross-section. The probe is mounted on a mechanism allowing it to move between multiple predetermined locations, enabling comprehensive uniformity measurement without requiring multiple separate test setups or extended preparation time for each measurement point.
Solution Approach 2:
The testing rig integrates multiple measurement capabilities into a single system. The same probe and positioning mechanism can measure various exhaust gas constituents (NOx, CO, hydrocarbons, oxygen) at multiple locations within a single test run, eliminating the need for separate dedicated measurement systems for each parameter and location combination.
2Manufacturing precision
If comprehensive uniformity mapping is performed across the exhaust flow cross-section, then design optimization is improved, but the number of measurements and design iterations increase
Solution Approach 1:
The system pre-establishes a grid of measurement locations across the exhaust flow cross-section before testing begins. These predetermined positions are optimized to capture the essential uniformity characteristics of the flow pattern. By having the measurement plan prepared in advance with optimal sampling points, the system achieves comprehensive design optimization data without requiring ad-hoc measurement decisions during testing iterations.
3Volume of stationary object
If catalyst sizing is minimized to meet cost and packaging requirements, then cost and footprint are reduced, but the system becomes more sensitive to uniformity variations
Solution Approach 1:
The measurement system captures spatially-resolved uniformity data across different regions of the exhaust flow cross-section. This detailed local information about concentration distributions allows engineers to understand how non-uniformities affect catalyst performance in different zones, enabling optimization of minimal catalyst sizing that accounts for local variations rather than requiring uniform performance margins across the entire catalyst surface.
Data Source
AI summary
An exemplary exhaust test tog apparatus includes a housing defining an exhaust flow path extending from an inlet to an outlet. At least a portion of the housing is selectably rotatable relative to an exhaust aftertreatment system. An arm extends from the housing into the exhaust flow path. An exhaust probe configured to measure an exhaust constituent is coupled with the arm and positioned at a location in the exhaust flow path. An actuator is configured to extend and retract the arm to vary the location of the exhaust probe in the exhaust flow path. The exhaust probe is moveable to a plurality of locations within the exhaust flow path through a combination of rotation of the housing and extension and retraction of the arm.