Exhaust Reagent Mixer with Flow-Redirection Housing
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Solution Overview
Problem
Existing exhaust aftertreatment systems for automotive applications are inefficient in reducing nitrogen oxides (NOx) emissions, as they require complex disassembly for catalyst servicing and often rely on non-serviceable SCR configurations, limiting the ability to effectively mix and distribute reagents across multiple catalysts.
Innovation Solution
A compact exhaust aftertreatment system incorporating a selective catalytic reduction unit (SCR) with a reagent mixer that injects and mixes a reagent, such as urea, into exhaust gases using a flow-redirection housing and multi-outlet discharge manifold, allowing for individual catalyst servicing and efficient NOx reduction by separating the gas stream into multiple paths for each catalyst housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a non-serviceable SCR configuration is used, then the system structure is simplified, but the ability to service and replace catalysts is lost
Solution Approach 1:
The SCR system is divided into separate, independently serviceable catalyst assemblies that can be removed and replaced without disassembling the entire aftertreatment system. Each catalyst is housed in its own housing with individual access points, enabling modular maintenance while preserving overall system integration.
2Ease of repair
If a complex disassembly procedure is required for catalyst servicing, then catalyst replacement is possible, but maintenance time and system downtime increase
Solution Approach 1:
The catalyst housings are pre-configured with quick-release latches and alignment features that enable rapid installation and removal. The mixing chamber and discharge manifold are pre-assembled as integrated units, eliminating the need for complex field assembly procedures and reducing maintenance time.
3Productivity
If multiple catalysts are used in parallel, then NOx reduction efficiency is improved, but the complexity of reagent distribution increases
Solution Approach 1:
Multiple catalyst housings are merged into a single integrated SCR assembly with a common mixing chamber and shared discharge manifold. The reagent injection system is consolidated into one location, and the mixing chamber distributes the reagent-exhaust mixture to all catalysts through the manifold, simplifying the overall reagent distribution architecture while maintaining parallel catalyst operation.
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 configuration enables effective transformation of NOx into harmless molecular nitrogen and water vapor, minimizing environmental impact while allowing for easy maintenance and serviceability of catalysts, thus enhancing the overall efficiency and cost-effectiveness of the system.
Implementation Method 1
Chemical reaction of the reagent with the exhaust gases occurs downstream of the reagent mixer in the SCR to transform the NOx into molecular nitrogen and water vapor
Data Source
AI summary
A vehicle includes an exhaust aftertreatment system for use with an automotive internal combustion engine. The system includes a reagent mixer configured to deliver a reagent for mixing with exhaust gases produced by the engine. The reagent mixer includes a flow-redirection housing defining an mixing chamber and a manifold coupled downstream of the flow-redirection housing. A doser is mounted to the flow-redirection housing and is configured to inject the reagent toward the mixing chamber.