US20150361847A1

US20150361847A1 - Valve assembly

Info

Publication number: US20150361847A1
Application number: US14/303,659
Authority: US
Inventors: Matthew F. Fahrenkrug; Theron J. Cassidy; Jason W. Hudgens; Jinhui Sun
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2014-06-13
Filing date: 2014-06-13
Publication date: 2015-12-17
Also published as: CN204716359U

Abstract

A valve assembly for an aftertreatment system is disclosed. The valve assembly includes a coolant conduit. The coolant conduit is configured to allow a coolant flow therethrough. The valve assembly also includes a valve element having a valve passage. The valve element is configured to control a reductant flow through the valve passage. The valve assembly further includes a coupling mechanism provided on the valve element. The coupling mechanism is configured to attach the valve element to the coolant conduit such that a temperature of the valve assembly is controlled based on the coolant flow.

Description

TECHNICAL FIELD

The present disclosure relates to a valve assembly of an aftertreatment system, and more particularly to a heating system associated with the valve assembly.

BACKGROUND

A reductant delivery module associated with an aftertreatment system of an engine may include a tank for storing a reductant, a pump, and reductant delivery lines. The reductant delivery lines may fluidly connect various components of the reductant delivery module for a flow of the reductant therethrough. The reductant delivery module also includes a valve mounted on a reductant return line from the pump to the reductant tank. On actuation, the valve is configured to allow a predetermined amount of the reductant from the pump to return into the reductant tank. In certain low temperature environments, the reductant is susceptible to freezing, thereby causing a portion of the reductant present within the valve to freeze and block and/or damage the valve. This may affect an overall working of the valve and performance of the system. Hence, there is a need to provide an improved valve design.
U.S. Application Publication Number 2013/0000729 describes a fluid supply system configured to be utilized with a coolant system of an engine, the fluid supply system including; a fluid tank, a fluid pump coupled to the fluid tank and a thermal management system in thermal communication with the fluid tank and the fluid pump, wherein the thermal management system includes; a first coolant circuit in thermal communication with the fluid tank and a second coolant circuit in thermal communication with the fluid pump, wherein flow of coolant from the coolant system through the first fluid circuit and second fluid circuit is in parallel when coolant flows through the second fluid circuit.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, a valve assembly for an aftertreatment system is disclosed. The valve assembly includes a coolant conduit. The coolant conduit is configured to allow a coolant flow therethrough. The valve assembly also includes a valve element having a valve passage. The valve element is configured to control a reductant flow through the valve passage. The valve assembly further includes a coupling mechanism provided on the valve element. The coupling mechanism is configured to attach the valve element to the coolant conduit such that a temperature of the valve assembly is controlled based on the coolant flow.
In another aspect of the present disclosure, an aftertreatment system is disclosed. The aftertreatment system includes a reductant tank. The aftertreatment system also includes a pump. The aftertreatment system further includes a coolant conduit. The coolant conduit is configured to allow a coolant flow therethrough. The aftertreatment system includes a valve assembly coupled to the pump and the reductant tank. The valve assembly includes a valve element having a valve passage. The valve element is configured to control a reductant flow from the pump to the reductant tank. The valve assembly also includes a coupling mechanism provided on the valve element. The coupling mechanism is configured to attach the valve element to the coolant conduit such that a temperature of the valve assembly is controlled based on the coolant flow.
In yet another aspect of the present disclosure, a valve assembly for an aftertreatment system is disclosed. The valve assembly includes a valve element having a valve passage. The valve element is configured to control a reductant flow through the valve passage. The valve assembly also includes a coolant manifold coupled to the valve element. The coolant manifold has an inner passage. The inner passage of the coolant manifold is configured to allow a coolant flow therethrough. Further, a temperature of the valve assembly is controlled based on the coolant flow.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary reductant delivery module of an aftertreatment system associated with an engine;

FIG. 2 is a perspective view of an exemplary valve assembly, according to an embodiment of the present disclosure; and

FIG. 3 is a perspective view of another embodiment of the valve assembly, according to various embodiments of the present disclosure.

DETAILED DESCRIPTION

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. FIG. 1 is a schematic diagram of an exemplary reductant delivery module 100 associated with an aftertreatment system. The aftertreatment system may form a part of an engine system. The engine system also includes an engine 101, which may be an internal combustion engine such as, for example, a reciprocating piston engine or a gas turbine engine. According to one embodiment of the present disclosure, the engine 101 is a spark ignition engine or a compression ignition engine such as, a diesel engine, a homogeneous charge compression ignition engine, a reactivity controlled compression ignition engine, or other compression ignition engine known in the art. The engine 101 may be fueled by gasoline, diesel, biodiesel, dimethyl ether, alcohol, natural gas, propane, hydrogen, combinations thereof, or any other combustion fuel known in the art.
The engine 101 may include other components such as, a fuel system, an intake system, a drivetrain including a transmission system, and so on. The engine 101 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. Further, the engine system may be associated with an industry including, but not limited to, transportation, construction, agriculture, forestry, power generation, and material handling.
The engine system includes the aftertreatment system fluidly connected to an exhaust manifold of the engine 101. The aftertreatment system is configured to treat an exhaust gas flow exiting the exhaust manifold of the engine 101. The exhaust gas flow contains emission compounds that may include Nitrogen Oxides (NOx), unburned hydrocarbons, particulate matter and/or other combustion products known in the art. The aftertreatment system may be configured to trap or convert NOx, unburned hydrocarbons, particulate matter, combinations thereof, or other combustion products in the exhaust gas flow before exiting the engine system.
The reductant delivery module 100 of the aftertreatment system is configured to inject a reductant into the exhaust gas flow. The reductant may be a fluid, such as, a Diesel Exhaust Fluid (DEF), and may include urea, ammonia, or other reducing agents known in the art. The reductant delivery module 100 includes a reductant tank 102, a pump 104, and a reductant injector 106, and will be explained later in this section. The aftertreatment system may further include other components such as a Selective Catalytic Reduction (SCR) module, a Diesel Oxidation Catalyst (DOC) and/or a Diesel Particulate Filter (DPF) not shown in the accompanying drawings. Variations in design of the aftertreatment system are possible without deviating from the scope of the disclosure and various other configurations not disclosed herein are also possible within the scope of this disclosure.
The reductant tank 102 of the reductant delivery module 100 is configured to store the reductant therein. Parameters related to the reductant tank 102 such as size, shape, location, and material used may vary as a function of system design and requirements. As shown in the accompanying figures, the reductant tank 102 is fluidly connected to the pump 104. The pump 104 is configured to pressurize and selectively deliver the reductant from the reductant tank 102 to the reductant injector 106 via a reductant conduit 107. The reductant is then introduced by the reductant injector 106 into an exhaust passage 108 of the engine 101. The pump 104 may receive the reductant from the reductant tank 102 through a reductant conduit 110. The pump 104 may include any pump known in the art including, but not limited to, a piston pump and a centrifugal pump. The reductant delivery module 100 illustrated in the accompanying figures includes a single pump and a single reductant injector. However, based on the type of application, the aftertreatment system may include multiple pumps and multiple reductant injectors without deviating from the scope of the present disclosure.
Under certain operating conditions the amount of the reductant delivered by the pump 104 may exceed a reductant flow demand from the reductant injector 106. In such a situation, the excess amount of the reductant supplied by the pump 104 may be recirculated to the reductant tank 102 via a reductant conduit 112. The reductant conduit 112 fluidly connects the pump 104 with the reductant tank 102. A valve assembly 114 may be provided in the reductant conduit 112 to regulate the reductant flow re-entering the reductant tank 102 from the pump 104. The valve assembly 114 may serve as a pressure regulator while returning the reductant to the reductant tank 102 during operation of the engine 101.
FIG. 2 is a perspective view of the valve assembly 114. The valve assembly 114 includes a valve element 202. The illustrated valve element 202 is an electrically controlled diaphragm valve; however alternative embodiments may include configurations wherein the valve element 202 may include other valve mechanisms, such as angle valves, piston valves, ball valves, rotary valves, sliding cylinder valves, etc. Further, while the valve element 202 as illustrated is electronically controlled, one of ordinary skill in the art would appreciate that other methods of controlling the valve, e.g., pneumatically, or hydraulically controlled valves, may alternatively be used.
The valve element 202 has a valve passage 204 provided therein. The reductant not required by the reductant injector 106 may recirculate from the pump 104 to the reductant tank 102 through the valve passage 204. Further, the valve passage 204 defines a centerline A-A. The valve passage 204 is embodied as a through-hole provided within the valve element 202. The valve element 202, and more particularly, the valve passage 204 of the valve element 202 may be opened or closed by electrical signals received from an electrical valve actuator 206 associated with the valve assembly 114. In the illustrated embodiment, the electrical valve actuator 206 is affixed atop the valve element 202. The electrical valve actuator 206 is configured to receive a control signal from a control module 120 (see FIG. 1). The control module 120 is communicably coupled to the electrical valve actuator 206, the pump 104, and the reductant injector 106 via control lines 122, 124, 126 respectively. In a situation wherein the reductant delivered by the pump 104 exceeds the reductant flow demand from the reductant injector 106, the control module 120 may send a control signal to the electrical valve actuator 206 in order to actuate the valve passage 204, thereby allowing the reductant to flow therethrough. In one example, the electrical valve actuator 206 may be a solenoid. Based on the system requirements, the valve element 202 may either operate in a default open position or a default closed position, and further be actuated by the control module 120 as required.
The valve assembly 114 also includes a pair of connection elements, namely a first connection element 208 and a second connection element 210. The connection elements 208, 210 are provided on opposing faces of the valve element 202. When the valve passage 204 is open, the reductant returning from the pump 104 is introduced into the valve passage 204 via the first connection element 208. The reductant may further flow through the valve passage 204, and leave therefrom through the second connection element 210. The reductant then flows downstream of the valve assembly 114, and into the reductant tank 102. The connection elements 208, 210 disclosed herein may be threadably coupled to the valve element 202, using mechanical couplings. Alternatively, the connection elements 208, 210 may be attached to the valve element 202 by welding or brazing. A person of ordinary skill in the art will appreciate that each of the connection elements 208, 210 in the accompanying figures include single port for connecting to the reductant conduit 112. However, in other embodiments, the connection elements 208, 210 may include an additional port, in order to accommodate other components, such as, an electric pigtail and so on.
It should be noted that the reductant flowing through various components of the reductant delivery module 100, such as, the reductant tank 102 and the pump 104 is susceptible to freezing. Freezing of the reductant may affect an overall performance of the aftertreatment system. Therefore, heating mechanisms are associated with the reductant delivery module 100 in order to increase a temperature of the reductant flowing therethrough.
A coolant may flow through a coolant system. The coolant may be any engine coolant that is configured to cool the engine 101. The coolant flowing through the coolant system is generally at a temperature which is higher than that of the reductant, due to heat transfer between the coolant and various engine parts. Hence, the coolant system may function as the heating mechanism for the aftertreatment system. In the illustrated embodiment, the coolant is free to flow throughout the coolant system. A coolant pump (not shown) may be provided in fluid communication with the coolant system. The coolant pump is configured to pump and deliver the coolant from a source such as a coolant tank to various components of the aftertreatment system.
Further, after a shutdown of the engine 101, the various components of the aftertreatment system are purged, so that the reductant present within these components may be removed therefrom. Accordingly, the valve assembly 114 is also purged. However during an operation of the engine 101, the reductant flowing through the valve assembly 114 may be susceptible to freezing. Freezing of the reductant within the valve assembly 114 may lead to a choking of the valve assembly 114, thereby increasing a quantity of the reductant upstream of the valve element 202. Unless otherwise prevented, freezing of the reductant may also damage the valve assembly 114.
In one embodiment, the valve element 202 (see FIG. 2) of the valve assembly 114 may be provided with insulation. Provision of the insulation may maintain and/or stop a further reduction in the temperature of the valve element 202 and also the temperature of the reductant flowing therethrough, thereby decreasing the susceptibility of the reductant to freeze within the valve assembly 114. In another embodiment, an electrically heated manifold may be attached to or provided near the valve element 202 in order to electrically heat the valve element 202 which in turn may increase the temperature of the reductant. In yet another embodiment, the valve element 202 may be designed such that the valve element 202 may be heated electrically. For example, heating coils may be provided surrounding or near the valve element 202 such that on passing an electric current therethrough, the heating coils heat the valve element 202, thereby increasing the temperature of the reductant flowing therethrough.
Referring to the accompanying figures, in other embodiments, the reductant flowing through the valve assembly 114 may exchange heat with the coolant that flows through the coolant system, such that the heat exchange avoids the freezing of the reductant within the valve assembly 114. The use of the engine coolant as the heating mechanism for the valve assembly 114 has several advantages. First, coolant flow paths already exist in the aftertreatment system for thawing and heating of the reductant, e.g., a coolant flow path through the reductant tank 102. The routing of an additional flow path to the valve assembly 114 requires minimal additional materials, cost, etc. Further, the heating mechanism of the present disclosure may be easily incorporated within the aftertreatment systems having space constraints. In addition, as opposed to electrical heating, the use of the engine coolant does not require an additional amperage requirement on the engine electrical system.
Referring to FIG. 2, the valve assembly 114 includes a coolant manifold 212. The coolant manifold 212 may be provided as a separate component, and later assembled with the valve element 202. More particularly, the valve element 202 is attached to a top portion of the coolant manifold 212. A coupling mechanism 213 may be provided in association with the valve assembly 114. The coupling mechanism 213 includes a pair of legs. The pair of legs extend from opposite sides of the valve element 202. In one example, the pair of legs includes an individual leg 214, 215 that extends from each side of the valve element 202. Further, the pair of legs 214, 215 has through-holes provided thereon. The through-holes are configured to receive mechanical fasteners 216, in order to affix the valve element 202 to the coolant manifold 212. The mechanical fasteners 216 may embody bolts, screws, rivets, and the like. Alternatively, the valve element 202 may be attached to the coolant manifold 212 using other methods, such as, adhesive, welding, or brazing.
As shown in FIG. 2, the coolant manifold 212 includes cross holes drilled therewithin. One of these holes defines an inner passage 218 of the coolant manifold 212. In one example, the inner passage 218 of the coolant manifold 212 is configured to receive a coolant conduit 220. Further, when provided within the inner passage 218, a centerline B-B defined by the coolant conduit 220 is parallel to the centerline A-A of the valve passage 204. One of ordinary skill in the art will appreciate that the coolant manifold 212 may include additional ports, for example the port providing connection for coolant conduit 224. The coolant conduit 224 may either allow the coolant flow to enter into or leave the coolant manifold 212, based on the system design and requirements.
The coolant conduit 220 disclosed herein is configured to allow the coolant to flow therethrough. The coolant conduit 220 may be embodied as a tube or a pipe, such that the coolant conduit 220 is coaxially received into the inner passage 118. The coolant conduit 220 may be connected to other components associated with the engine 101 and the coolant system. It should be noted that parameters associated with the valve assembly design, for example, the distance between the valve passage 204 the inner passage 218 may vary, such that optimum heat exchange takes place between the reductant and the coolant flowing through the valve assembly 114.
The coolant may flow through various components of the aftertreatment system. In one example, the coolant may flow through the reductant tank 102 and the pump 104. Referring to FIG. 1, the coolant from various components of the system may enter into the valve element 202 via the coolant conduit 220. On passing through the coolant conduit 220, the coolant may evenly dissipate heat around the valve element 202, such that the reductant is maintained in the flowing state during the engine operation. FIG. 3 illustrates another embodiment of the valve assembly 300. In this design, the valve element 302 and the coolant manifold 312 may be formed as a single, unitary, and indivisible component, such that the coolant manifold 312 extends from a lower portion of the valve element 302. Also, a centerline X-X defined by the valve passage 304 is parallel to a centerline Y-Y defined by the inner passage 318. Similar to the embodiment explained in connection with FIG. 2, the valve element 302 includes the valve passage 304 for the flow of the reductant therethrough.
The valve assembly 300 may include the coolant conduit 320 provided within the inner passage 318. The coolant conduit 320 allows the flow of coolant therethrough. The valve assembly 114 may be operated in a similar manner as explained above based on signals received from the control module 120 (see FIG. 1). Further, the coolant flowing through the coolant manifold 312 may exchange heat with the reductant flowing through the valve element 302 in order to minimize or prevent the freezing of the reductant within the valve element 302 during the operation of the engine 101.

INDUSTRIAL APPLICABILITY

Reductant delivery modules include a back flow valve. In an open position, the back flow valve recirculates the excess amount of reductant from the pump into the reductant tank. The reductant flowing through the back flow valve may be susceptible to freezing. Freezing of the reductant may choke the back flow valve, thereby obstructing reductant flow therethrough. In one situation, the freezing reductant may also damage the back flow valve. Further, the freezing of the reductant may flood the flow passage between the pump and the back flow valve, which is not desirable.
The present disclosure describes the valve assembly 114, 300 including the valve element 202, 302 and the coolant manifold 212, 312. Further, the coolant conduit 220, 320 is received within the inner passage 218, 318 of the coolant manifold 212, 312. During engine operation, the high temperature coolant is configured to flow through the coolant conduit 220, 320 or the inner passage 218, 318. The high temperature coolant exchanges heat with the reductant flowing through the valve passage 204, 304, thereby increasing the temperature of the reductant and keeping the reductant thawed all the time.
The present solution eliminates the freezing of the valve assembly 114, 300 at low ambient conditions. Further, the system of the present disclosure also eliminates the requirement of additional components for freeze prevention of the valve assembly 114, 300. The coupling mechanism 213 may provide a compact design in aftertreatment systems having space constraints. Also, as shown in FIG. 2, the coupling mechanism 213 and the coolant manifold 212 may firmly couple the valve element 202 with the coolant conduit 220, such that the valve element 202 may be held in place even when experiencing engine vibration.
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

What is claimed is:

1. A valve assembly for an aftertreatment system, the valve assembly comprising:

a coolant conduit configured to allow a coolant flow therethrough;

a valve element having a valve passage, the valve element configured to control a reductant flow through the valve passage; and

a coupling mechanism provided on the valve element, the coupling mechanism configured to attach the valve element to the coolant conduit such that a temperature of the valve assembly is controlled based on the coolant flow.

2. The valve assembly of claim 1, wherein the coupling mechanism includes at least two legs extending from the valve element.

3. The valve assembly of claim 2, wherein the at least two legs extend from opposite faces of the valve element.

4. The valve assembly of claim 2 further comprising:

a coolant manifold having an inner passage, the inner passage configured to receive the coolant conduit therein.

5. The valve assembly of claim 4, wherein the coupling mechanism includes a mechanical fastener configured to attach the at least two legs to the coolant manifold.

6. The valve assembly of claim 1, wherein the valve element is attached to the coolant conduit such that a centerline of the valve passage is parallel to a centerline of the coolant conduit.

7. The valve assembly of claim 1 further comprising:

a pair of connection elements provided on opposing faces of the valve element, the pair of connection elements configured to attach a reductant line to the valve passage.

8. The valve assembly of claim 1, wherein the valve assembly is electrically controlled.

9. An aftertreatment system comprising:

a reductant tank;

a pump;

a coolant conduit configured to allow a coolant flow therethrough; and

a valve assembly coupled to the pump and the reductant tank, the valve assembly comprising:

a valve element having a valve passage, the valve element configured to control a reductant flow from the pump to the reductant tank; and

10. The aftertreatment system of claim 9, wherein the coupling mechanism includes at least two legs extending from the valve element.

11. The aftertreatment system of claim 10, wherein the at least two legs extend from opposite faces of the valve element.

12. The aftertreatment system of claim 10 further comprising:

13. The aftertreatment system of claim 12, wherein the coupling mechanism includes a mechanical fastener configured to attach the at least two legs to the coolant manifold.

14. The aftertreatment system of claim 12, wherein each of the valve element and the coolant manifold are unitary components.

15. The aftertreatment system of claim 9, wherein the valve assembly is electrically controlled.

16. A valve assembly for an aftertreatment system, the valve assembly comprising:

a coolant manifold coupled to the valve element, the coolant manifold having an inner passage, the inner passage configured to allow a coolant flow therethrough,

wherein a temperature of the valve assembly is controlled based on the coolant flow.

17. The valve assembly of claim 16, wherein the valve assembly is a unitary component.

18. The valve assembly of claim 16, wherein a centerline of the valve passage is parallel to a centerline of the inner passage.

19. The valve assembly of claim 16, wherein each of the valve element and the coolant manifold are unitary components.

20. The valve assembly of claim 16, wherein the valve assembly is electrically controlled.