Exhaust Gas Recirculation Duct Funnel Geometry for Back Pressure Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current exhaust gas aftertreatment systems face challenges in reducing nitrogen oxide emissions and managing installation space, leading to increased flow resistance and back pressure in internal combustion engines, particularly due to the placement of SCR catalytic converters and particle filters, which complicates quick heating and efficient exhaust gas recirculation.
Innovation Solution
The system incorporates a filter element with a large oval inlet cross-section funnel and a decoupling element to reduce back pressure, combined with a compact design that includes a bend-free exhaust gas duct and a displaceable exhaust gas recirculation duct, optimizing the flow cross-section and minimizing vibrations and pressure waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the SCR catalytic converter and particle filter are arranged in an underbody position remote from the engine, then the exhaust gas aftertreatment components can be installed with sufficient space, but the installation space is limited and the components cannot be heated up quickly after cold start
Solution Approach 1:
The patent utilizes the vertical dimension by routing the exhaust gas recirculation duct through the vehicle's underbody space in a three-dimensional path, allowing the EGR system to connect remote components without occupying additional horizontal installation space. This dimensional approach resolves the conflict between remote component placement and space constraints.
2Area of stationary object
If the SCR catalytic converter and particle filter are arranged close to the engine, then the components can be heated up quickly after cold start, but the installation space is limited and flow resistance increases
Solution Approach 1:
The patent employs curved and tapered duct geometries with optimized flow paths that minimize turbulence and pressure losses. The smooth transitions and curved surfaces in the exhaust gas recirculation duct reduce flow resistance, allowing compact component arrangement without significant energy losses.
3Loss of energy
If a funnel geometry is used to reduce back pressure in close-coupled SCR systems, then the back pressure is reduced, but a large amount of installation space is required or the catalytic converters must be designed with small volumes requiring frequent regeneration
Solution Approach 1:
The patent applies funnel geometry only at specific critical locations where flow expansion is needed, rather than throughout the entire duct system. This localized application of flow management features reduces back pressure at key points while maintaining compact overall dimensions and avoiding excessive installation space requirements.
4Productivity
If the exhaust gas recirculation line is arranged downstream of the turbine, then the nitrogen oxide reduction efficiency is improved, but the flow resistance and back pressure in the exhaust gas duct increase
Solution Approach 1:
The patent introduces an intermediate exhaust gas recirculation duct that branches from the main exhaust duct downstream of the turbine. This intermediary pathway allows a portion of the exhaust gas to be redirected to the intake tract while maintaining the main exhaust flow path, thereby achieving NOx reduction without significantly increasing overall back pressure in the primary exhaust system.
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 reduces exhaust gas back pressure, enhances the efficiency of nitrogen oxide reduction, and allows for a more compact exhaust aftertreatment system, improving engine performance and reducing consumption.
Implementation Method 1
a filter element (70) is arranged on the second funnel (66), through which the exhaust gas flow can flow, by means of which solid and/or liquid exhaust gas components can separate out
Implementation Method 2
a decoupling element (44) is arranged in the exhaust gas recirculation channel (42) downstream of the second funnel (66)
Implementation Method 3
a catalytic converter for the selective catalytic reduction of nitrogen oxides (SCR catalytic converter) and a particle filter for separating soot particles
Implementation Method 4
Ammonia is preferably used as the reducing agent
Implementation Method 5
This mixing heats up the aqueous urea solution, with the aqueous urea solution releasing ammonia in the exhaust gas duct
Implementation Method 6
the aqueous urea solution releasing ammonia in the exhaust gas duct
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an exhaust aftertreatment system for an internal combustion engine, comprising an exhaust duct, a particulate filter, and a low-pressure exhaust gas recirculation system branching off from the exhaust duct downstream of a filter element of the particulate filter. The particulate filter has a housing that tapers downstream of the filter element in the form of a first funnel, the first funnel branching into a second funnel and a third funnel. The second funnel preferably has an oval inlet geometry and a round outlet geometry and is connected to an exhaust gas recirculation channel of the low-pressure exhaust gas recirculation system. The third funnel is connected to a main duct of the exhaust system and directs a main exhaust gas flow from the particulate filter towards a tailpipe of the exhaust duct.