Exhaust Bellows Separation Structure for Urea Deposit Control
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Solution Overview
Problem
Urea derivative deposits form in flexible line elements of exhaust systems upstream of SCR catalytic converters, leading to mobility issues and potential damage due to accumulation and inability to be dissolved by hot exhaust gas flows, compromising the system's fluid tightness and functionality.
Innovation Solution
A separation device, such as a baffle plate or filter-like structure with a large surface area, is placed upstream of the flexible line element to intercept and collect urea derivatives from the edge layer of the exhaust gas stream, preventing them from adhering to the metal bellows and allowing for their dissolution during regeneration or high temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible line element with metal bellows is installed upstream of an SCR catalyst to accommodate engine movements and vibrations, then the system's adaptability and vibration damping are improved, but urea derivative deposits accumulate in the bellows causing mobility restrictions and potential damage
Solution Approach 1:
The invention extracts the harmful urea derivatives from the exhaust gas stream before they can enter and accumulate in the metal bellows. A separation device is positioned upstream of the bellows to remove urea derivatives from the gas flow, preventing their deposition in the flexible line element and thus maintaining its reliability and mobility.
Solution Approach 2:
The separation device acts as an intermediary component between the urea injection system and the flexible line element. It intercepts urea derivatives in the exhaust gas and prevents them from reaching the metal bellows, thereby protecting the flexible connection from deposit accumulation while allowing the system to maintain its flexibility and adaptability.
2Productivity
If urea is injected upstream of the flexible line element to enable SCR catalyst operation, then nitrogen oxide reduction is achieved, but urea derivatives deposit in the flexible line element causing blockages
Solution Approach 1:
The invention converts the harmful effect of urea derivative deposition into a beneficial separation process. The separation device is designed to capture and collect urea derivatives that would otherwise harm the flexible line element. By providing a designated collection area, the system transforms the problematic deposit formation into a controlled separation function, protecting the metal bellows while maintaining SCR efficiency.
Solution Approach 2:
The separation device extracts urea derivatives from the exhaust gas stream before they can contaminate the flexible line element. This extraction function allows the system to maintain both SCR catalyst productivity and protection against deposit-related harm by removing the harmful components from the gas flow upstream of the bellows.
3Length of moving object
If the flexible line element is positioned close to the engine to minimize relative movement, then the bellows length is reduced, but deposits still accumulate in the bellows area
Solution Approach 1:
The separation device removes urea derivatives from the exhaust gas stream before they can reach and deposit in the metal bellows, even when the bellows is positioned close to the engine. This extraction function ensures that the shortened bellows length does not compromise the system's protection from deposit accumulation.
Solution Approach 2:
The separation device performs preliminary action by removing urea derivatives from the exhaust gas before the gas enters the flexible line element. This preliminary cleanup ensures that even when the bellows is short and positioned close to the engine, deposits cannot accumulate because the harmful substances have already been extracted from the gas stream.
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
Effectively reduces and relocates urea derivative deposits away from critical areas, maintaining the flexible line element's functionality and fluid tightness, and ensures that deposits are collected and can be dissolved under appropriate conditions, preventing blockages and damage.
Implementation Method 1
A metal bellows is capable of absorbing axial, lateral, and angular movements caused by temperature-related length changes, load-changing movements of the combustion engine, and, in vehicles, vibrations during operation
Implementation Method 2
vibrations of various frequencies generated in the combustion engine by the moving parts and pulsating gas flows are absorbed by the metal bellows and, provided their natural vibrations are sufficiently damped, are not transmitted to the downstream parts of the exhaust system
Implementation Method 3
A separation device, such as a baffle plate or filter-like structure with a large surface area, is placed upstream of the flexible line element to intercept and collect urea derivatives from the edge layer of the exhaust gas stream
Implementation Method 4
allowing for their dissolution during regeneration or high temperature conditions
Data Source
Figure 1~2
AI summary
The present invention relates to a flexible line element for the exhaust system of an internal combustion engine, with a metal bellows (11) which is ring-corrugated or corrugated in the form of a screw thread and through which an exhaust gas flow (4) can flow and a line section (1) arranged upstream of the metal bellows, wherein in the line section (1) arranged upstream of the metal bellows 1), or attached to it, a separating device (2,5,6,7,9,13,14,16,17,18) for urea derivatives carried along in a surface layer (3) of the exhaust gas flow or for urea from a supersaturated with this Edge layer of the exhaust gas flow is provided.