Double-Walled Hose Leak Detection in Reducing Agent Dosing
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Solution Overview
Problem
Existing reducing agent dosing systems for internal combustion engines fail to accurately detect leaks in the delivery line and nozzle removal, which can lead to inefficiencies and inaccuracies in nitrogen oxide reduction in selective catalytic reduction processes.
Innovation Solution
A reducing agent metering system utilizing a double-walled hose with pressure and temperature sensors to monitor the inner and outer hoses, allowing for reliable detection of leaks and correct nozzle alignment through pressure and temperature monitoring, and a compressed air supply for atomization and line cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-walled delivery line is used, then the device complexity is reduced, but the ability to detect leaks and nozzle removal is insufficient
Solution Approach 1:
The delivery line is segmented into two separate channels: an inner line for reducing agent transport and an outer line for compressed air supply. This segmentation allows independent monitoring of each fluid path, enabling leak detection through pressure differential measurement between the two lines without requiring complex sensor systems.
Solution Approach 2:
The inner delivery line is nested within the outer air supply line, forming a concentric double-walled structure. This nesting arrangement allows the compressed air to flow around the reducing agent line, creating a natural pressure barrier that enables leak detection when pressure differences between inner and outer lines are monitored.
2Ease of operation
If compressed air is supplied through the outer hose, then atomization and line cleaning are improved, but the risk of reducing agent freezing increases
Solution Approach 1:
The outer hose acts as an intermediary thermal barrier between the compressed air supply and the reducing agent in the inner hose. By supplying warm compressed air through the outer hose, the system creates a thermal protection layer that prevents the reducing agent from freezing while still enabling effective atomization at the nozzle.
Solution Approach 2:
The system provides beforehand thermal cushioning by continuously supplying warm compressed air through the outer hose before freezing conditions can affect the reducing agent. This preventive measure ensures the reducing agent remains at operational temperature even in cold environments.
3Reliability
If pressure monitoring is implemented in the delivery line, then leak detection is improved, but the system cannot distinguish between leaks and nozzle removal
Solution Approach 1:
The system uses dual pressure monitoring with feedback comparison: pressure sensors in both the inner reducing agent line and outer air line continuously monitor pressure levels. By comparing the pressure differential between the two lines and analyzing pressure changes over time, the system can distinguish between leak conditions (gradual pressure equalization) and nozzle removal (sudden pressure change patterns).
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
Ensures accurate and reliable detection of leaks and nozzle misalignment, preventing inefficiencies and ensuring effective nitrogen oxide reduction, while also preventing freezing of the reducing agent solution.
Implementation Method 1
pressure sensors to monitor the inner and outer hoses, allowing for reliable detection of leaks and correct nozzle alignment through pressure and temperature monitoring
Implementation Method 2
temperature sensors to monitor the inner and outer hoses, allowing for reliable detection of leaks and correct nozzle alignment through pressure and temperature monitoring
Implementation Method 3
a compressed air supply for atomization and line cleaning
Data Source
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AI summary
The reducing agent dosing system has a feed pump (1), particularly a pump unit, by which a reducing agent (2) is conveyed from a reducing agent tank over a conveying line and is introduced in an exhaust gas stream (4) of an internal combustion engine over a nozzle (3). The feed line is formed by a double-walled feed line (5), particularly a double-walled hose, where the reducing agent is conveyed through an inner line (6). The reducing agent is sprayed inside or outside the nozzle by compressed air. An independent claim is included for a method for operating a reducing agent dosing system.