The present disclosure relates to an injector mount, and more particularly to a reductant injector mount associated with an aftertreatment system of an engine.
An aftertreatment system is associated with an engine system. The aftertreatment system is configured to treat and reduce oxides of nitrogen (NOx) present in an exhaust gas flow, prior to the exhaust gas flow exiting into the atmosphere. In order to reduce NOx, the aftertreatment system may include a reductant delivery module, a reductant injector, and a Selective Catalytic Reduction (SCR) module.
The reductant injector is configured to inject a reductant into the exhaust gas flowing through a mixing tube of the aftertreatment system. The reductant may include urea. In order to achieve improved levels of NOx conversion, better flow distribution and mixing of the reductant with the exhaust gases must be achieved. A mixing system is affixed inside the mixing tube so that increased turbulence and improved distribution of the reductant within the exhaust gases may be achieved within a length of the mixing tube.
A reductant injector mount is used to couple the reductant injector to the mixing tube. However, urea deposit formation may take place in an area near to an injection point of the reductant injector. Such urea deposition may hinder or prevent reductant spray and/or interaction with the exhaust gas flow, and may also cause a reduction in NOx conversion in the aftertreatment system.
U.S. Pat. No. 8,079,211 describes systems and methods provided for injecting liquid reductant into an engine exhaust. In one example, the system includes a gas deflector positioned upstream of an injector where the gas deflector is configured to create a high pressure zone upstream of the deflector and a low pressure zone downstream of the deflector surrounding the injector outlet. A bypass flow passage diverts exhaust flow from the high pressure zone upstream of the deflector to allow the bypassed portion of exhaust to flow into the exhaust gas stream to form a gas shield for a liquid reductant spray from the injector.
In one aspect of the present disclosure, a reductant injector mount is provided. The reductant injector mount includes a mounting region configured to connect to an exhaust conduit. The reductant injector also includes a contoured region formed in the mounting region. The contoured region is configured to increase a velocity of an exhaust gas flow through the contoured region. The contoured region is also configured to reduce a recirculation of the exhaust gas flow through the contoured region. Further, the reductant injector mount includes a cut out portion provided on the contoured region. The cut out portion is configured to receive a reductant injector tip therethrough.
In another aspect of the present disclosure, an aftertreatment system is provided. The aftertreatment system includes an exhaust conduit having a cut out region. The aftertreatment system also includes a selective catalytic reduction module coupled to the exhaust conduit. The aftertreatment system further includes a reductant injector mount disposed on the exhaust conduit. The reductant injector mount is positioned upstream of the selective catalytic reduction module with respect to an exhaust gas flow. The reductant injector mount includes a mounting region connected to the exhaust conduit. The reductant injector mount also includes a contoured region formed in the mounting region. The contoured region faces an inner side of the exhaust conduit. The contoured region is configured to increase a velocity of the exhaust gas flow through the contoured region. The contoured region is also configured to reduce a recirculation of the exhaust gas flow through the contoured region. Further, the reductant injector mount includes a cut out portion provided on the contoured region. The aftertreatment system includes a reductant injector in fluid communication with the exhaust conduit, wherein the reductant injector mount is received through the cut out portion provided on the reductant injector mount.
In yet another aspect of the present disclosure, a method of controlling an exhaust gas flow in an exhaust conduit is provided. The method includes receiving a reductant injector through a mounting region of a reductant injector mount. The method also includes flowing an exhaust gas flow on a contoured region of the reductant injector mount. The method further includes increasing a velocity of the exhaust gas flow through the contoured region based on the flow. The method includes reducing a recirculation of the exhaust gas flow through the contoured region based on the flow.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. An exemplary embodiment of a machine 100, according to the present disclosure is shown in
The machine 100 also includes a plurality of ground-engaging elements 106, in this case being wheels. As should be appreciated by one of ordinary skill in the art, an engine 108 (see
Referring to
The engine 108 may include other components (not shown), such as, a fuel system, an intake system, a drivetrain including a transmission system, and so on. The engine 108 may be used to provide power to any machine including, but not limited to, an on-highway truck, an off-highway truck, an earth moving machine, an electric generator, and so on. Accordingly, the engine system 104 may be associated with an industry including, but not limited to, transportation, construction, agriculture, forestry, power generation, and material handling.
Referring to
In the illustrated embodiment, the aftertreatment system 114 includes a first module 116 that is fluidly connected to an exhaust conduit 118 of the engine 108. During engine operation, the first module 116 is arranged to internally receive engine exhaust gas from the exhaust conduit 118. The first module 116 may contain various exhaust gas treatment devices, such as, a Diesel Oxidation Catalyst (DOC) 120 and a Diesel Particulate Filter (DPF) 122, but other devices may be used. The first module 116 and the components found therein are optional and may be omitted for various engine applications in which the exhaust treatment function provided by the first module 116 is not required.
In the illustrated embodiment, the exhaust gas flow provided to the first module 116 by the engine 108 may first pass through the DOC 120 and then through the DPF 122 before entering a conduit 123. The conduit 123 includes a mixing tube 124. Further, the aftertreatment system 114 includes a reductant supply system 126. A reductant is injected into the mixing tube 124 by a reductant injector assembly 127. The reductant injector assembly 127 may include one or more reductant injectors 128 (see
The reductant supply system 126 includes a reductant tank 130. The reductant is contained within the reductant tank 130. Parameters related to the reductant tank 130 such as size, shape, location, and material used may vary according to system design and requirements. Further, the reductant injector 128 may be communicably coupled to a controller (not shown). Based on control signals received from the controller, the reductant from the reductant tank 130 is provided to the reductant injector 128 by a pump assembly 132. As the reductant is injected into the mixing tube 124, the reductant mixes with the exhaust gas flow passing therethrough, and is carried to a second module 134. Further, the conduit 123 is configured to fluidly interconnect the first module 116 with the second module 134, such that, the exhaust gas flow from the engine 108 may pass through the first and second modules 116, 134 in series before being released at a stack 136 connected downstream of the second module 134.
The second module 134 encloses a Selective Catalytic Reduction (SCR) module 138 and an Ammonia Oxidation Catalyst (AMOX) 140. The SCR module 138 operates to treat exhaust gases exiting the engine 108 in the presence of ammonia, which is provided after degradation of a urea-containing solution injected into the exhaust gas flow in the mixing tube 124. The AMOX 140 is used to convert any ammonia slip from the downstream flow of the SCR module 138 before exiting the stack 136.
The aftertreatment system 114 disclosed herein is provided as a non-limiting example. It will be appreciated that the aftertreatment system 114 may be disposed in various arrangements and/or combinations relative to the exhaust manifold. These and other variations in aftertreatment system design are possible without deviating from the scope of the disclosure.
Reductant injector mounts 200, 202 are associated with the aftertreatment system 114. The reductant injector mounts 200, 202 are positioned upstream of the SCR module 138 with respect to an exhaust gas flow direction “F”. Further, the reductant injector mounts 200, 202 are attached to a top portion 146 of the mixing tube 124. The reductant injector mounts 200, 202 may be attached to the mixing tube 124 using a joining process, such as welding. Alternatively, any joining process, such as brazing, soldering, may be used. Further, mechanical fasteners or an adhesive may also be used for attaching the reductant injector mounts 200, 202 to the mixing tube 124. As shown in the accompanying figures, the reductant injector mounts 200 are disposed in a direction parallel to the exhaust gas flow direction “F”. Whereas, the reductant injector mounts 202 are disposed in an angular orientation with respect to the exhaust gas flow direction “F”. The reductant injector mount 200, 202 is configured to mount the reductant injector 128 onto the mixing tube 124. A number of the reductant injector mounts 200, 202 may depend on a number of the reductant injectors 128 associated with the aftertreatment system 114, and may vary based on system requirements.
The mixing tube 124 of the present disclosure includes two reductant injectors 128 associated therewith. Therefore, the mixing tube 124 includes two reductant injector mounts 200, 202 mounted to the top portion 146 of the mixing tube 124. It should be noted that the number of reductant injectors and the reductant injector mounts may vary. In one example, four reductant injectors and the corresponding reductant injector mounts may be provided on the mixing tube 124. The design of the reductant injector mount 200 will now be explained with reference to
Referring to
The reductant injector mount 200 includes a mounting region 402. The mounting region 402 is configured to be connected to and in contact with the mixing tube 124. The mounting region 402 referred to herein collectively refers to the top surface 405 of the first portion 404 and the second portion 406 facing the exhaust gas flow.
The mounting region 402 of the reductant injector mount 200 may include a plurality of receiving elements 408. In the illustrated embodiment, the reductant injector mount 200 includes three receiving elements 408. However, a number of the receiving elements 408 may vary as per system requirements. The receiving elements 408 project from the mounting region 402 of the reductant injector mount 200.
In one example, the receiving elements 408 are configured to receive mechanical fasteners (not shown) of the reductant injector 128, in order to couple the reductant injector 128 to the reductant injector mount 200. The receiving elements 408 include apertures 411 (see
The reductant injector mount 200 includes a contoured region 410. The contoured region 410 is formed in the mounting region 402. The contoured region 410 is configured to provide a flow field for the exhaust gases flowing therethrough. The contoured region 410 is designed such that the contoured region 410 may increase a velocity of the exhaust gas flow through the contoured region 410. The contoured region 410 may also be configured to reduce a recirculation of the exhaust gases flowing therethrough. The direction of the exhaust gas flow through the contoured region 410 is marked by arrows “F” in
The reductant injector mount 200 includes a cut out portion 412. The cut out portion 412 is provided on the contoured region 410 of the reductant injector mount 200. More particularly, the cut out portion 412 is positioned in a throat portion 414 of the contoured region 410. The cut out portion 412 is configured to receive a reductant injector tip 416 of the reductant injector 128 therethrough. As shown in
As illustrated in
Referring to
Referring to
In one embodiment of the present disclosure, the width “W1” of the first lobe 424 may be equal to the width “W2” of the second lobe 426. Therefore, the ratio “R1” may be equal to the ratio “R2”. Accordingly, the ratio “R2” of the width “W2” of the second lobe 426 to the diameter “D” of the cut out portion 412 is approximately from 0.75 to 5. In some embodiments, the ratio “R2” is approximately from 0.75 to 2.5 or 2.5 to 5. In one example, the ratio “R2” may be approximately equal to 2.5. Alternatively, the width “W1” of the first lobe 424 may be different than the width “W2” of the second lobe 426. In such an example, the ratio “R1” may be different than the ratio “R2”.
When the reductant injector mount 200 is mounted on the mixing tube 124, a curved surface of the contoured region 410 of the reductant injector mount 200 faces the exhaust gas flow. The curvature of the contoured region 410 varies along a cross section of the reductant injector mount 200. Referring to
More particularly, the receiving angle “α1” is formed by an upstream end 436 of the first lobe 424 with respect to the mounting region 402 of the reductant injector mount 200. The exhaust gas flow is received on the contoured region 410 of the reductant injector mount 200 at the receiving angle “α1”. In one embodiment, the angle of incidence “α1” of the contoured region 410 at the first lobe 424 is approximately from 3° to 45°. In one example, the angle of incidence “α1” may be approximately 6°. Further, the angle of incidence “α2” of the contoured region 410 at the second lobe 426 is approximately from 10° to 45°. For example, the angle of incidence “α2” may be approximately 17°.
Referring to
Referring now to
As discussed earlier, based on system requirements, the reductant injector mounts 202 may be positioned angularly on the mixing tube 124 with respect to the exhaust gas flow direction “F” (see
Flow field around an injection location of the reductant injector mounted on the mixing tube may have unfavorable recirculating and/or low velocity patterns of the exhaust gas flow. This may create/increase formation of urea deposits that may be present in the reductant. Such urea deposition can prevent/hinder the reductant spray pattern/interaction with the exhaust gas flow and further cause deposition issues and reduce NOx conversion in the aftertreatment system.
At step 1008, based on the flow, the recirculation of the exhaust gas flow flowing through the contoured region 410, 704, 802, 902 is reduced. The exhaust gas flow is then discharged towards the SCR module 138 provided downstream of the conduit 123. The flow field provided by the contoured region 410, 704, 802, 902 of the reductant injector mount 200, 202, 700, 800 has reduced or no recirculation around the reductant injector tip 416 and also increases the velocity near the injection location.
Accordingly, the deposit formation of the reductant around the reductant injector tip 416 may reduce or be eliminated because of reduced recirculation and increased velocity of the exhaust gas flow through the reductant injector mount 200, 202, 700, 800. Further, the reductant may uniformly mix with the exhaust gas flow and an improved NOx conversion may take place in the aftertreatment system 114. Also, servicing and maintenance associated with removal of the reductant deposits close to the reductant injector 128 may be reduced, thereby decreasing cost associated with servicing and maintenance cost of the aftertreatment system 114.
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.