FLOW MIXING DEVICE FOR AN EXHAUST AFTER-TREATMENT SYSTEM
A flow mixing device includes a body having a first end, a second end, and an interior volume defined between them. An inlet plate, coupled to the first end of the body, defines at least two inlet orifices in fluid communication with the interior volume. Similarly, an outlet plate, coupled to the second end defines an outlet passage of the flow mixing device. A diffuser conduit, coupled to the inlet plate, defines an inlet passage disposed in fluid communication with the respective inlet orifices. A separator plate assembly disposed in the interior volume extends partially between the first and second ends of the body. Flow guiding vanes, coupled proximal to the second end, extend partially within the diffuser conduit.
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The present disclosure relates to an exhaust gas after-treatment system of an internal combustion engine. More particularly, the present disclosure relates to a flow mixing device of the exhaust gas after-treatment system.
BACKGROUNDInternal combustion engines have been typically known to employ exhaust after-treatment systems to lower or reduce undesired emissions in an exhaust stream. One of the undesired emissions in the exhaust stream may include nitrous oxides (NOx). A Selective catalytic reduction (SCR) system may be additionally utilized to reduce the quantity of NOx emissions in the exhaust stream. The SCR system is configured to inject a reductant such as urea in the exhaust stream to convert harmful NOx emissions into harmless nitrogen and water.
A flow mixer may be used to combine multiple exhaust streams generated from the internal combustion engine into a single exhaust stream prior to injection of a reductant. A uniform mixing of the exhaust gases is required to maximize flow uniformity and minimize backpressure prior to entry of the exhaust gases at the reductant injection location.
U.S. Pat. No. 8,814,969 discloses an exhaust gas emission control system for an internal combustion engine. The exhaust gas emission control system includes a cylindrical body through which the exhaust flows. The cylindrical body has an inflow pipe and an outflow pipe. The inflow pipe includes a louvre member defining a plurality of slits having varying height. A height of the slits decreases on moving away from a center of the inflow pipe. Although the louvre member may provide a uniform flow and minimize backpressure to an extent, it does not uniformly mix two separate exhaust streams into a single exhaust stream for effectively reducing NOx.
Hence, there is a need for an improved system that provides uniform mixing of multiple exhaust streams into a single exhaust stream while also minimizing backpressure and maximizing flow uniformity.
SUMMARY OF THE DISCLOSUREIn an aspect of the present disclosure, a flow mixing device for an exhaust after-treatment system of an internal combustion engine includes a body having a first end and a second end disposed distally away from one another. The body defines an interior volume. The flow mixing device further includes an inlet plate coupled to the first end of the body. The inlet plate having at least two inlet orifices formed therein in fluid communication with the interior volume, Further, an outlet plate is coupled to the second end of the body. The outlet plate defines an outlet passage in fluid communication with the interior volume. The flow mixing device further includes a diffuser conduit releasably coupled to the inlet plate and disposed around each of the inlet orifices. The diffuser conduit configured to define an inlet passage disposed in fluid communication with the inlet orifices of the inlet plate and the interior volume of the body. The flow mixing device further includes a separator plate assembly includes a first separator plate and a second separator plate, the first and second separator plates coupled at an angle relative to each other at the first end of the body and converging towards a longitudinal plane defined between the pair of diffuser conduits. The flow mixing device further includes multiple flow guiding vanes coupled to the body proximal to the second end and configured to extend at least partially within the diffuser conduit.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts. Moreover, references to various elements described herein are made collectively or individually when there may be more than one element of the same type. However, such references are merely exemplary in nature. It may be noted that any reference to elements in the singular may also be construed to relate to the plural and vice-versa without limiting the scope of the disclosure to the exact number or type of such elements unless set forth explicitly in the appended claims.
As shown in
The engine 102 may be any type of engine (internal combustion, gas, diesel, gaseous fuel, natural gas, propane, etc.), may be of any size, with any number of cylinders, and in any configuration (“V,” in-line, radial, etc.). The engine 102 may be used to power any machine or other device, including on-highway trucks or vehicles, off-highway trucks or machines, earth moving equipment, generators, aerospace applications, locomotive applications, marine applications, pumps, stationary equipment, or other engine powered applications.
As shown in the embodiment of
Exhaust gases 106 from the first and second exhaust conduits 110, 112 are passed through a flow mixing device 118 to combine the two separate exhaust streams 106 into a single combined exhaust stream 120. As shown in the embodiment of
The SCR system 122 includes a reductant supply system 124 and an SCR catalyst 126. The reductant supply system 124 can include one or more of the following: a reductant 128, a reductant source 130, a pump 132, a valve 134 and an injector 136. The reductant 128 is drawn from the reductant source 130 via the pump 132 and delivery to the injector 136 that is controlled via the valve 134. The flow of reductant 128 may also be controlled by operation of the pump 132. While other reductants 128 are possible, urea is the most commonly used reductant 128. Reductant 128 decomposes or hydrolyzes into ammonia (NH3) and is then adsorbed or otherwise stored in the SCR catalyst 126. The SCR catalyst 126, provided downstream of the injector 136, includes a catalyst material disposed on a substrate. The substrate may consist of cordierite, silicon carbide, other ceramic, or metal. The substrate may include a plurality of through going channels and may form a honeycomb structure.
After passing through the SCR system 122, the exhaust stream 120 may be circulated back to an exhaust gas recirculation system (not shown), a turbocharger (not shown) or discharged in atmosphere.
As shown in
The first and the second diffuser conduits 150, 152 define a first inlet passage 158 and a second inlet passage 160, respectively. Each of the first and the second inlet passages 158, 160 is in fluid communication with the respective first and the second orifices 146, 148. Exhaust stream 106 flowing through the first exhaust conduit 110 is received at the first inlet passage 158 and passes on to the first inlet orifice 146, through the first diffuser conduit 150. Similarly, the exhaust stream 106 flowing through the second exhaust conduit 112 is received at the second inlet passage 160 and passes on to the second inlet orifice 148, through the second diffuser conduit 152.
As shown in
The flow mixing device 118 has a first inner surface 164 and a second inner surface 166. The first inner surface 164 and the second inner surface 166 are mutually opposed to each other and extend between the inlet plate 144 and the outlet plate 162.
The flow mixing device 118 further includes a separator plate assembly 168. The separator plate assembly 168 is located in the interior volume coupled to the body 138. As shown in the sectional view of
Further, the flow mixing device 118 includes multiple flow guiding vanes 174 located in the interior volume and on either side of the separator plate assembly 168. The flow guiding vanes 174 extend from the first end 140 of the body 138 to the second end 142 of the body 138. The flow guiding vanes 174 extend longitudinally between the first inner surface 164 and the second inner surface 166. In an embodiment, the flow guiding vanes 174 may also extend partway between the first and second inner surfaces 164, 166. In another embodiment, the flow guiding vanes 174 may extend fully between the first inner surface 164 and the second inner surface 166.
As shown in the embodiment of
With continued reference to
In an embodiment as shown in
The perforated plate 194 is further supported on the outlet plate 162 through a cross member 196. The cross member 196 is a structural element that may include two sheet metal bars joined together in an intersecting manner so as to form a support structure for the perforated plate 194. The perforated plate 194 is coupled to the cross member 196 along the length of the two bars. Also, the perforated plate 194 is located around the center of the second end 142 leaving an open space 198 between the periphery of the perforated plate 194 and the outlet plate 162. Further, in an embodiment, the perforations provided in the perforated plate 194 may be uniform in size. Alternatively, the perforations may vary in size and in proportion to the distance from a center of perforated plate 194.
INDUSTRIAL APPLICABILITYThe flow mixing device 118, explained in the present disclosure, minimizes a backpressure while mixing two or more exhaust streams and output a single exhaust stream. Further, the flow mixing device 118 helps in maintaining a desired flow profile of the exhaust stream prior to injection of the reductant. The flow mixing device 118 helps in providing the exhaust stream a low velocity profile at center which allows the reductant to be injected substantially symmetrically and uniformly.
In order to explain functioning of the flow mixing device 118, reference will now be made to
After passing through the first and the second diffuser conduits 150, 152, the exhaust stream 106 from the first and the second exhaust conduits 110, 112 flow across the flow guiding vanes 174. As the flow guiding vanes 174 have one or more bends, the exhaust stream 106 gradually change flow directions along the bends. Thereafter, exhaust streams 106 from the first and second. exhaust conduits 110, 112 mix with each other to form the combined exhaust stream 120. Uniform flow profile of the combined exhaust stream 120 is provided by the separator plate assembly 168 and the flow guiding vanes 174 effecting gradual and uniform mixing of the exhaust streams 106 from the two exhaust conduits 110, 112.
In another embodiment of the current disclosure as shown in
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
Claims
1. A flow mixing device for an exhaust after-treatment system of an internal combustion engine, the flow mixing device comprising:
- a body having a first end and a second end disposed distally away from one another, the body configured to define an interior volume therein;
- an inlet plate coupled to the first end of the body, the inlet plate having at least two inlet orifices formed therein in fluid communication with the interior volume;
- an outlet plate coupled to the second end of the body, the outlet plate defining an outlet passage in fluid communication with the interior volume;
- a diffuser conduit releasably coupled to the inlet plate and disposed around each of the inlet orifices, the diffuser conduits configured to define an inlet passage disposed in fluid communication with the inlet orifices of the inlet plate and the interior volume of the body;
- a separator plate assembly comprising a first separator plate and a second separator plate, the first and second separator plates coupled at an angle relative to each other at the first end of the body and converging towards a longitudinal plane defined between the pair of diffuser conduits; and
- a plurality of flow guiding vanes coupled to the body proximal to the second end and configured to extend at least partially within the diffuser conduits.
2. The flow mixing device of claim 1 further including a perforated plate coupled to the outlet plate of the body, the perforated plate configured to allow a substantially uniform flow profile of a fluid exiting the body.
Type: Application
Filed: Mar 11, 2016
Publication Date: Jul 7, 2016
Applicant: Caterpillar Inc. (Peoria, IL)
Inventors: Kevin Weiss (Peoria, IL), Mohamed I. Daoud (Dunlap, IL), Yung T. Bui (Peoria, IL), Arvind Jujare (Peoria, IL), Chiranjeevi Mangamuri (Peoria, IL), Timothy Alcenius (Dunlap, IL)
Application Number: 15/067,204