Exhaust Gas Cleaning Component Bypass Evaporation
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Solution Overview
Problem
Existing exhaust gas cleaning systems face challenges in ensuring adequate evaporation of liquid exhaust gas cleaning additives, particularly under cold starting conditions of internal combustion engines, and often require excessive heating energy, with the formation of solid deposits being a concern when aqueous urea solutions do not evaporate sufficiently.
Innovation Solution
An exhaust gas cleaning component featuring a housing with a metal honeycomb body and a feed device that atomizes the additive, which is sprayed onto the outer surface of a heated shell, utilizing a bypass duct and optional heaters to enhance evaporation, ensuring reliable evaporation with minimal heating energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid exhaust gas cleaning additive is fed to exhaust gas treatment device, then exhaust gas cleaning is achieved, but adequate evaporation is not ensured under cold starting conditions
Solution Approach 1:
The exhaust gas flow is divided into a main flow passing through the honeycomb body and a bypass flow that does not pass through the honeycomb body. The liquid exhaust gas cleaning additive is fed into the bypass flow, allowing it to evaporate on the outer surface of the honeycomb body shell where it receives heat from the main exhaust gas flow, ensuring reliable evaporation under cold starting conditions.
Solution Approach 2:
The outer surface of the honeycomb body shell acts as an intermediary surface for heat transfer. The bypass flow with the fed additive flows over this heated surface, allowing indirect heating and evaporation of the additive without direct contact with the hot exhaust gas in the main flow, ensuring controlled and reliable evaporation.
2Reliability
If heating systems are used to ensure adequate evaporation, then evaporation reliability is improved, but heating energy consumption increases
Solution Approach 1:
The system uses the thermal energy already present in the main exhaust gas flow to evaporate the additive in the bypass flow. The honeycomb body shell acts as a heat exchanger, transferring heat from the main flow to the bypass flow, allowing the system to self-regulate evaporation without additional heating energy input.
Solution Approach 2:
The thermal energy in the exhaust gas that would otherwise be wasted is recovered and used to evaporate the liquid additive. By directing part of the exhaust gas through the bypass duct and allowing it to flow over the heated honeycomb body outer surface, the system recovers thermal energy for the evaporation process.
3Reliability
If aqueous urea solution is used as liquid exhaust gas cleaning additive, then effective nitrogen oxide reduction is achieved, but solid deposit formation occurs when evaporation is insufficient
Solution Approach 1:
The outer surface of the honeycomb body shell serves as a heated intermediary surface that ensures complete evaporation of the aqueous urea solution before it can form solid deposits. The bypass flow design allows sufficient residence time on the heated surface for complete vaporization, preventing deposit formation in the exhaust system.
Solution Approach 2:
The system changes the temperature parameter of the additive by flowing it over the heated honeycomb body outer surface. This temperature increase ensures complete evaporation of the aqueous urea solution, transforming it from liquid to vapor phase and preventing solid deposit formation downstream.
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 solution enables effective evaporation of liquid exhaust gas cleaning additives under cold conditions with reduced heating energy consumption and minimizes deposit formation, ensuring efficient operation of the exhaust gas treatment device.
Implementation Method 1
liquid exhaust gas cleaning additives must evaporate in order to be able to act in the exhaust gas
Implementation Method 2
a first honeycomb body (5) arranged in the housing and having a shell (7), wherein the shell (7) has an outer surface (8), over which exhaust gas can flow within the housing
Implementation Method 3
one known practice is for liquid additives to be added in finely atomized form in order to improve the evaporation of the liquid exhaust gas cleaning additives
Implementation Method 4
utilizing a bypass duct and optional heaters to enhance evaporation
Data Source
AI summary
An exhaust gas cleaning component, having a housing with an inflow port and an outflow port, a first honeycomb structure in the housing with a casing, the casing having an outer surface over which exhaust gas can flow, and also having an applicator device by which an exhaust gas cleaning additive can be applied to the outer surface of the casing.