Spiral Housing Mixing Device for Exhaust Gas Homogeneity
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Solution Overview
Problem
Existing mixing devices for exhaust gas after-treatment in internal combustion engines face challenges in achieving homogeneous mixing of liquids or liquid-gas mixtures with exhaust gases due to uneven flow and pressure conditions, leading to asymmetrical spray distribution and potential clogging of particle filters.
Innovation Solution
A mixing device with a spiral-shaped housing section that extends along all access openings of the inner tube, ensuring uniform flow and pressure conditions, combined with exhaust gas guide elements to direct the flow and prevent liquid or liquid-gas mixture escape, results in rotationally symmetrical flow conditions and homogeneous mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If exhaust gas is introduced through bores of a guide plate into a mixing area, then mixing of exhaust gas with liquid spray is achieved, but the exhaust gas exerts varying forces on the spray in the circumferential direction leading to deflection and asymmetrical spray pattern
Solution Approach 1:
The patent employs a spiral housing section that creates a curved flow path for the exhaust gas. This spiral geometry transforms the linear exhaust flow into a rotating flow pattern that uniformly distributes the gas forces around the circumferential direction, preventing spray deflection and maintaining symmetrical spray patterns while achieving thorough mixing.
Solution Approach 2:
The housing is divided into a spiral housing section that segments the exhaust gas flow into multiple circumferential paths. This segmentation allows the exhaust gas to be distributed more uniformly around the mixing area, creating consistent flow conditions that prevent asymmetrical spray patterns while maintaining effective mixing.
2Device complexity
If a conventional mixing device without spiral housing is used, then the structure is simpler, but uniform flow and pressure conditions cannot be achieved leading to inhomogeneous mixing
Solution Approach 1:
The spiral housing section introduces a curved geometric element that transforms the flow characteristics without requiring complex internal components. The spiral shape naturally generates the necessary flow uniformity and pressure distribution through its geometric properties, achieving homogeneous mixing conditions with a relatively simple structural addition.
3Quantity of substance
If the metering device supplies liquid spray into the exhaust stream, then the liquid is introduced for aftertreatment, but without uniform flow conditions the spray distribution becomes asymmetrical reducing mixing efficiency
Solution Approach 1:
The spiral housing section creates a rotating flow field that uniformly distributes the liquid spray introduced by the metering device. The curved flow path ensures that the spray is exposed to consistent exhaust gas forces in all circumferential directions, maintaining symmetrical spray patterns and maximizing mixing efficiency throughout the mixing area.
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 ensures the most homogeneous possible mixing of liquids or liquid-gas mixtures with exhaust gases, reducing the risk of particle filter clogging and improving engine performance and fuel efficiency by maintaining uniform flow and pressure conditions, even under varying exhaust gas volume flows.
Implementation Method 1
The housing has a spiral housing section, the spiral housing section extending at least along all access openings of the inner tube
Implementation Method 2
a metering device for supplying a liquid and/or a liquid-gas mixture is arranged on an end face of the housing
Implementation Method 3
an inner tube arranged within the housing with a mixing area formed inside the inner tube, wherein the inner tube has access openings on its outer surface through which the exhaust gases can be introduced into the mixing area
Data Source
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AI summary
The invention provides a mixing device (2) for the aftertreatment of exhaust gases in the exhaust system of an internal combustion engine, comprising a housing (4) with an inlet opening (24) having an inlet cross-section and an inner tube (6) arranged within the housing (4) with a mixing area (8) formed inside the inner tube (6), wherein a metering device (10) for supplying a liquid and/or a liquid-gas mixture (14) is arranged on an end face of the housing (4), and wherein the inner tube (6) has access openings (18) on its outer surface (16) through which the exhaust gases can be introduced into the mixing area (8). The housing (4) has a spiral housing section (22), wherein the spiral housing section (22) extends at least along all access openings (18).Furthermore, the invention provides a method for mixing exhaust gas with a liquid and/or a liquid-gas mixture using a aforementioned mixing device (2).