Exhaust Baffle Plate Layout for Accurate Aftertreatment Sensors
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Solution Overview
Problem
Current exhaust gas aftertreatment system sensors are prone to false positives due to inadequate flow characteristics, such as rate, direction, and field, exacerbated by compact system configurations and recirculation regions, which impact sensor accuracy and compliance with emissions regulations.
Innovation Solution
A baffle plate device with side extensions and a baffle aperture is positioned within the outlet conduit to deflect a portion of the treated exhaust gas towards sensor tips, improving flow characteristics and ensuring accurate measurements by eliminating recirculation regions and optimizing gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If aftertreatment systems are configured in a compact arrangement to reduce size and weight, then system compactness is improved, but sensor measurement accuracy deteriorates due to recirculation regions and poor flow characteristics
Solution Approach 1:
A baffle plate is introduced as an intermediary component between the exhaust gas flow and the sensor. The baffle plate redirects the flow to eliminate recirculation regions and improve flow characteristics at the sensor tip, thereby resolving the contradiction between compact system size and sensor measurement accuracy
Solution Approach 2:
The baffle plate modifies the local flow characteristics specifically at the sensor location without changing the overall compact system architecture. By creating a localized flow redirection zone, the sensor accuracy is improved while maintaining the compact configuration of the entire aftertreatment system
2Measurement precision
If sensors are positioned in the flow path to measure exhaust gas composition, then measurement capability is improved, but false positives increase due to insufficient flow rate and recirculation regions
Solution Approach 1:
The baffle plate serves as a mediator that conditions the flow before it reaches the sensor, ensuring adequate flow rate and eliminating recirculation. This improves both measurement capability and reliability by preventing false positives while maintaining accurate measurements
3Volume of moving object
If the outlet conduit is designed with bends and curves to accommodate compact packaging, then system compactness is improved, but flow characteristics deteriorate causing recirculation regions
Solution Approach 1:
The baffle plate is positioned within the curved outlet conduit to counteract the adverse flow effects of the bends. It acts as a local flow conditioner that redirects exhaust gas to eliminate recirculation regions, thereby improving flow characteristics without requiring changes to the overall compact conduit design
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 baffle plate device enhances sensor accuracy, reducing false positives and negatives, thereby improving emissions compliance and engine performance by ensuring precise pollutant measurements.
Implementation Method 1
The first and second side extensions are configured to deflect a first portion of the treated exhaust gas in the flow path towards first and second tips of first and second sensors
Implementation Method 2
a baffle aperture disposed between the first and second side extensions and configured to permit passage of another portion of the treated exhaust gas in the flow path
Data Source
AI summary
Baffle plate devices, exhaust gas aftertreatment apparatuses, and methods for controlling airflow in exhaust gas aftertreatment apparatuses are disclosed. In some examples, a baffle plate device is mounted within an outlet conduit via which the exhaust gas treated by an exhaust gas aftertreatment apparatus exits to the environment. The baffle plate device impacts the flow path of the treated exhaust gas within the outlet conduit to deflect a portion of the treated exhaust gas toward tips of sensors, which extend into the flow path toward the baffle plate device, in order to mitigate the impact of the recirculation region, improve the flow characteristics (e.g., rate, direction, and/or field) of the treated exhaust gas at the tips, and thereby improve the accuracy of the sensors. By improving sensor accuracy, the disclosed technology advantageously reduces false positives and improves engine performance and emissions compliance.