Modular Reductant Metering System for Compact SCR Applications
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Solution Overview
Problem
Existing reducing agent dosing systems for selective catalytic reduction in internal combustion engines are complex and require significant installation space, limiting their use in motor vehicles where space is a critical factor.
Innovation Solution
A modular reducing agent dosing system comprising two integrated structural units: a dosing unit with a feed pump, suction, pressure connections, and compressed air supply, and a compressed air unit with a controlled valve, allowing for flexible placement and omission of a mixing chamber, thus optimizing space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional reducing agent dosing system with mixing chamber is used, then effective aerosol formation is achieved, but the installation space requirement increases and assembly complexity increases
Solution Approach 1:
The mixing chamber is extracted and removed from the system. Instead of forming aerosol in a separate mixing chamber, the reducing agent is atomized directly at the injection nozzle using compressed air, eliminating the need for a mixing chamber and reducing installation space.
Solution Approach 2:
The aerosol formation function is merged with the injection nozzle. The atomization process is integrated directly at the nozzle where the reducing agent is injected, combining the functions of injection and aerosol formation in a single component location.
2Reliability
If a conventional reducing agent dosing system with mixing chamber is used, then effective aerosol formation is achieved, but the assembly complexity increases
Solution Approach 1:
The mixing chamber is extracted and removed from the system. Instead of forming aerosol in a separate mixing chamber, the reducing agent is atomized directly at the injection nozzle using compressed air, eliminating the need for a mixing chamber and reducing installation space.
Solution Approach 2:
The aerosol formation function is merged with the injection nozzle. The atomization process is integrated directly at the nozzle where the reducing agent is injected, combining the functions of injection and aerosol formation in a single component location.
3Area of stationary object
If a modular design with integrated units is used, then installation space is reduced and assembly is simplified, but the system requires precise coordination of multiple units
Solution Approach 1:
The dosing system is segmented into modular integrated units that can be installed separately. The feed pump unit and injection unit are separate modules that can be assembled and installed independently, reducing installation space and simplifying assembly while maintaining system functionality.
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 modular design reduces installation space requirements, simplifies assembly, and eliminates the need for a mixing chamber, enhancing the system's compactness and operational efficiency while maintaining effective aerosol formation and reducing nitrogen oxide emissions.
Implementation Method 1
with a feed pump by means of which reducing agent is drawn from a reducing agent tank via a suction connection and conveyed via a pressure connection
Implementation Method 2
the reducing agent is atomized by means of compressed air outside the nozzle
Implementation Method 3
the second integrated unit is designed as a compressed air unit and has at least one controlled valve for regulating the compressed air supply
Implementation Method 4
the reducing agent metering system has a modular design consisting of at least two integrated components, wherein the first integrated component is designed as a dosing unit
Data Source
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AI summary
The invention relates to a reductant-metering system (10) for injecting a reductant into the exhaust-gas flow of an internal combustion engine for selective catalytic reduction, comprising a conveying pump, by means of which reductant from a reductant tank (40) is suctioned from the tank (40) via a suction connection piece (23) and conveyed via a pressure connection piece (50) and introduced into the exhaust-gas flow of the internal combustion engine via at least one nozzle (60), wherein the metering system (10) has a compressed-air supply and the reductant is atomized by means of compressed air outside of the nozzle (60), wherein the reductant-metering system (10) has a modular structure consisting of at least two integrated assemblies (20, 30), wherein the first integrated assembly is designed as a metering unit (20) and has at least the pump, the suction connection piece, the pressure connection piece, and a compressed-air connection and wherein the second integrated assembly is designed as a compressed-air unit (30) and has at least one controlled valve for controlling the compressed-air supply.