Patent Application
20080098499
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and, together with the written description, serve to explain the principles of the disclosed system. In the drawings:
Exhaust system 10 may include a flow assembly 14 positioned upstream of an exhaust device 16. Flow assembly 14 may be positioned at any suitable location within exhaust system 10 and configured to receive a flow of exhaust gas. Specifically, flow assembly 14 may be configured to modify an exhaust stream such that gas flow downstream of flow assembly 14 may be more uniform than a gas flow upstream of flow assembly 14. For example, flow assembly 14 can be configured to redistribute a gas flow to provide a more uniform velocity and/or pressure profile of gas exiting flow assembly 14 than gas entering flow assembly 14. In addition, flow assembly 14 could be modular, wherein flow assembly 14 can be manufactured to form a single device, as described in detail below. Flow assembly 14 in modular form could be readily placed within and/or removed from exhaust system 10.
Exhaust system 10 may include one or more exhaust devices 16 designed to reduce the levels of emissions discharged into the surrounding environment. For example, exhaust device 16 may include catalytic converters, filters, or any suitable device configured to at least partially remove any unwanted material produced by power source 12. In some embodiments, exhaust device 16 may include a diesel particulate filter (DPF) or other type of filter configured to trap particulates, soot, or other materials found in exhaust gas.
Flow assembly 14 may be located upstream of exhaust device 16 such that exhaust gas entering exhaust device 16 may have a generally uniform flow profile. A generally uniform flow profile may include a gas flow that is generally uniform over a cross-section of the gas flow. For example, a turbulent flow may include a more uniform velocity and/or pressure profile over a cross-sectional area of gas flow than a velocity and/or pressure profile associated with laminar flow. A gas velocity at the center of turbulent gas flow may be similar to a gas velocity adjacent to the perimeter of the turbulent gas flow, while a gas velocity at the center of a laminar gas flow may be dissimilar to a gas velocity adjacent to the perimeter of the laminar gas flow.
A generally uniform gas flow exiting from flow assembly 14 can flow into exhaust device 16. Such an even distribution of gas flow entering exhaust device 16 can reduce the likelihood that one region of a cross-section of exhaust device 16 will receive significantly more gas flow than another region of the cross-section exhaust device 16. Overloading a region of exhaust device 16 by passing an increased gas flow through the filter material can lead to premature clogging of the overloaded region of filter material. In contrast, other filter regions of exhaust device 16 receiving less gas flow may remain under-utilized. A generally uniform gas flow entering exhaust device 16 can improve the efficiency of exhaust device 16 by more evenly distributing gas flow throughout exhaust device 16. For example, such a uniform gas profile may improve the efficiency of a filter by evenly loading the filter material, and/or reducing the frequency of filter regeneration procedures.
In some embodiments, housing 18 may be dimensioned and configured for placement upstream and/or adjacent to exhaust device 16. Housing 18 may include any suitable cross-sectional shape, such as, for example, a circular, oval, square, rectangular, triangular, or combinations thereof. Further, housing 18 may be tapered, whereby an outer and/or inner dimension may increase and/or decrease along a longitudinal axis (y axis) of housing 18.
Flow assembly 14 may include any number of blades 19. In particular, flow assembly 14 may include a first blade set 20 and a second blade set 22, wherein each blade set 20, 22 may include one or more blades 19. Each blade set can include one or more blades 19 positioned in a row within housing 18. Specifically, each blade of a blade set can be generally located on a common plane, such as, for example, a lateral plane within housing 18 represented by the x-z plane in
In some embodiments, blade sets 20, 22 can be located at two distinct lateral planes within a lumen 23 of flow assembly 14. Lumen 23 may fluidly connect a proximal aperture located at a proximal portion of housing 18 to a distal aperture 26 located at a distal portion of housing 18. Proximal aperture 24 can be configured to receive a gas flow within exhaust system 10. Distal aperture 26 can be configured to exit a gas flow upstream of exhaust device 16.
As shown in
First blade set 20 may include any number of blades 28 and second blade set 22 may include any number of blades 30, wherein blades 28, 30 may be configured to modify gas flow within flow assembly 14. Blades 28, 30 may be suitably distributed and configured within lumen 23 to create a generally uniform gas flow. For example, blades 28, 30 may be distributed radially in the x-z plane within lumen 23, as shown in
In some embodiments, blades 28, 30 may extend radially from an inner surface of housing 18 toward a center of lumen 23. In other embodiments, blades may extend across lumen 23, from one location on the perimeter of lumen 23 to another location on the perimeter of lumen 23, and may be positioned parallel, perpendicular, or at any appropriate angle to other blades within housing 18. Blades 28, 30 may also be positioned at any suitable angle relative to a longitudinal axis (y axis) of housing 18. For example, first blade set 20 may include one or more blades 28 at a first angle while second blade set 22 may include one or more blades 30 at a second angle. Specifically, one or more blades 28 may be angled at +30 degrees to a longitudinal axis, while one or more blades 30 may be angled at −30 degrees to the longitudinal axis. Also, one or more blades within a blade set can be positioned at angles different to angles of one or more other blades with the same blade set.
Blades 19 may be any suitable shape, including generally planar, tapered, or curvilinear, such as, for example, convex or concave configurations. Blades 19 may also include various features (not shown), such as, for example, extensions, indentations, coatings, or other surface features configured to enhance generation of turbulent flow and/or creation of a uniform gas flow. Also, first blade set 20 and/or second blade set 22 may include one or more different types of blades 19. For example, blades 28, 30 may include different shapes, distributions, and/or configurations within lumen 23.
Blades 19 may include a tip 32 and a base 34, wherein base 34 is connected to housing 18 and tip 32 is located within lumen 23. In some embodiments, blades 28, 30 may be positioned and configured such that blade tips 32 do not extend to a center of lumen 23. Such a blade arrangement may permit generally unobstructed gas flow through a central passageway 36, wherein central passageway 36 may permit sufficient gas flow through a center of lumen 23 to create a generally uniform gas flow exiting flow assembly 14. Specifically, central passageway 36 may be substantially free of blades 19 and may extend from proximal aperture 24 to distal aperture 26. In addition, blades 19 may be shaped, distributed, and/or configured to provide a generally uniform gas flow in combination with central passageway 36.
Initially, a blade blank 52 can be produced from a sheet of suitable material (not shown). For example, blade blank 52 may be separated from the sheet of material by stamping, cutting, ablating, or similar process. Blade blank 52 may then be formed into a blade insert 54. In some embodiments, formation of blade insert 54 may include one or more intermediate processes, wherein one or more intermediate blanks 53 are produced. As shown in
Following formation of blade insert 54, two or more blade inserts 54 can be positioned within and fixedly attached to housing 18. Housing 18 may be formed from any suitable material as previously described, such as, for example. tubular steel. Housing 18 can be appropriately sized and shaped for placement within exhaust system 10, and configured to receive two or more blade inserts 54.
In some embodiments, two blade inserts 54, 54′ may be positioned within housing 18. As shown in
Blade inserts 54, 54′ can be fixedly attached to housing 18 following appropriate positioning of blade inserts 54, 54′ within housing 18. Blade inserts 54, 54′ may be fixedly attached using welding, brazing, clamping, friction fitting, threading, or other suitable fixation method. Various other steps and manufacturing processes can be used during the formation of flow assembly 14, such as, for example, coating, grinding, polishing, or heat treating.
Traditional exhaust systems may include various filters, catalytic converters, and other devices configured to remove particulate matter and other constituents from exhaust gas. Such exhaust systems can include ducts with bends, tortuous sections, or other configurations that may inadvertently create an uneven flow of exhaust gas. Uneven exhaust flow may cause clogging of some regions of a filter while under-utilizing other filter regions as different quantities of exhaust gas may pass through different regions of the filter material. Regions of material exposed to high gas flow may clog more quickly than other regions of material exposed to lower gas flow rates. Such uneven gas flow may reduce filter performance. For example, premature clogging may decrease the operational life of the filter and/or increase the need for filter regeneration. The present disclosure provides a flow assembly configured to create a more uniform gas flow upstream of an exhaust device, such as a particulate filter, thereby increasing filter performance. The present disclosure also provides an efficient method of manufacturing the flow assembly.
Flow assembly 14 may modify a non-uniform exhaust flow to create a more uniform exhaust flow by redirecting the exhaust flow passing through flow assembly 14. Flow assembly 14 may be positioned upstream of a filter or similar device that may benefit from an entering gas flow being generally uniform. In addition, flow assembly 14 should be capable of functioning in a range of exhaust system configurations and over a range of engine operating conditions. For example, flow assembly 14 should be configured to operate with exhaust gas temperatures of about 700° C. Also, flow assembly 14 should ideally only slightly increase any backpressure, require minimal or no maintenance, and be relatively inexpensive to manufacture.
As described previously, flow assembly 14 may include two or more sets of blades 20, 22, wherein each set of blades may include a plurality of blades 19. Blade shape, angle, and/or position may all be varied to increase the turbulence of the exhaust flow passing through flow assembly 14 to create a generally uniform flow profile. For example, blades 19 can be tapered whereby blade base 34 may be larger than blade tip 32, tilted at an angle relative to a longitudinal axis (y axis) of flow assembly 14, and/or positioned such that each blade is evenly radially distributed.
A generally uniform flow profile from flow assembly 14 should result without significantly increasing backpressure due to the presence of flow assembly 14 in exhaust system 10. Such performance can be obtained if flow assembly 14 includes two sets of twelve tapered blades positioned within two distinct lateral planes, wherein the blades are evenly distributed radially. One set of blades can be titled at +30° and the other set of blades can be titled at −30° with respect to a longitudinal axis of flow assembly 14. Such a blade arrangement may permit formation of a generally uniform gas flow without significantly raising backpressure. The blade arrangement may impart sufficient turbulence into the gas flow passing through flow assembly 14 to alter the flow profile of the exhaust gas. In addition, central passageway 36 can provide sufficient flow of exhaust gas through the center of lumen 23 to create a generally uniform gas flow without significantly increasing backpressure.
The present disclosure also provides an efficient method of manufacturing flow assembly 14. As shown and discussed above, flow assembly 14 can be manufactured in a simple and robust manner. In addition, only three components are required to produce flow assembly 14. These components require minimal machining and can be processed using standard manufacturing equipment. Therefore, the manufacturing method may permit low-cost manufacturing of flow assembly 14.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed flow assembly and manufacturing method. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed system. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.
