Patent Application
20110151760
The present disclosure relates generally to an exhaust system and, more particularly, to an exhaust system having one or more baffles disposed near the discharge end.
Internal combustion engines, including diesel engines, gasoline engines, natural gas engines, turbine engines, and other engines known in the art, are used to drive many types of power systems. Exhaust from the internal combustion engines is typically discharged into the atmosphere. A power system may include an exhaust stack that extends vertically from the engine or from an enclosure of the engine in order to discharge the exhaust. As such, it is possible for precipitation to enter the exhaust stack when the engine is non-operational (i.e., when the exhaust stack is not being pressurized by a flow of exhaust). When the engine is operational, precipitation can also enter the exhaust stack where the exhaust flow is weakest.
Moisture in the exhaust system can damage various exhaust system components, such as after-treatment devices. For example, diesel particular filters (DPFs) often utilize a ceramic wall-flow substrate. When the engine is non-operational in cold environments, water in the exhaust system may freeze. If in contact with the ceramic substrate, the freezing and expansion of the water may crack the substrate.
To avoid problems with moisture, such as precipitation, entering the exhaust system via a vertically extending stack, some stacks include protective devices. For example, U.S. Pat. No. 2,630,748 (hereinafter the '748 patent), by Brockelsby, discloses an exhaust rain protector. The '748 patent discloses using an adapter that mounts onto a vertically extending exhaust pipe. The adapter includes a pair of angled baffles that divert any rain water entering the exhaust discharge end out a pair of spouts and create maze-like flow path for the exhaust that prevents water from entering the exhaust system past the baffles.
While the device disclosed in the '748 patent may prevent rainwater from entering the exhaust system, it requires fitting an offset, bulky adapter onto the end of the exhaust pipe that increase space and height of the exhaust stack. Furthermore, the device is ill-suited for exhaust stacks already having an angled discharge end. Still further, the maze-like flow path may result in an undesirable increase in exhaust back pressure.
The present disclosure is directed to overcoming one or more of the shortcomings in the existing technology.
In accordance with one aspect, the present disclosure is directed an exhaust stack having a first section defining a first flow passage extending along a first longitudinal axis and a second section having an open end and defining a second flow passage extending along a second longitudinal axis. The exhaust stack further includes a liquid drain disposed in the first section and one or more baffles disposed in the second flow passage, wherein the one or more baffles are configured to block line-of-sight between the open second end and any inner surface below the liquid drain.
According to another aspect, the present disclosure is directed toward a method of protecting exhaust system components from liquid entering an exhaust stack discharge port. The method includes providing a liquid drain along an exhaust flow path in the exhaust stack, blocking line-of sight between the exhaust stack discharge port and any inner surface of the exhaust system below the liquid drain, and positioning one or more baffles in the exhaust stack such that liquid falling by gravity from the one or more baffles will contact an inner surface of the exhaust stack between the liquid drain and the one or more baffles.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
In the accompanying drawings, which are incorporated in and constitute a part of this specification, exemplary embodiments of the disclosure are illustrated, which, together with the written description, serve to explain the principles of the disclosed system:
Referring to
The housing 16 may be any structure that encloses or partially encloses the engine 12 and exhaust system 14. For example, the housing 16 may be a vehicle body or hood.
The exhaust system 14 may include an exhaust manifold 18, one or more exhaust aftertreatment devices 20 designed to reduce undesirable emissions from the exhaust of the engine 12, and an exhaust stack 22. The exhaust aftertreatment devices 20 may include a variety of emissions treatment technology, including, but not limited to, regeneration devices, heat sources, oxidation catalysts, diesel oxidation catalysts (DOCs), diesel particulate filters (DPFs), selective catalytic reduction catalysts (SCRs), lean NOx traps (LNTs), mufflers, or other devices needed to treat the exiting the engine 12.
In the depicted embodiment, the exhaust aftertreatment devices 20 include a diesel particulate filter (DPF) 24. The DPF 24 may include a DPF substrate 26 at least partially disposed within a DPF housing 28. The DPF substrate 26 may be configured in a variety of ways. Any structure capable of removing particulate matter from the exhaust of the engine 12 may be used. For example, the DPF substrate may a wall-flow ceramic structure having a honey-comb cross-section constructed of cordierite, silicon carbide, or other material to remove the particulate matter.
The exhaust stack 22 may be configured in a variety of ways. Any structure capable of routing exhaust exiting the power system 10 in a desired direction may be used. For example, the cross-sectional shape of the exhaust stack 22 may be circular or may be some other geometric shape. The exhaust stack 22 may extend substantially vertically upward or may extend at an angle to vertical. Referring to
The first section 30 may include a liquid drain 42. The liquid drain 42 may be configured in a variety of ways. Any structure capable of collecting or redirecting liquid (such as water) that flows down the first inner surface 36 of the first section 30 may be used. In the depicted embodiment, the liquid drain 42 is configured as an annular trough having a bottom wall 44 disposed between a sidewall 46 and the first inner surface 36. One or more apertures 48 may be formed in the first inner surface 36 adjacent the bottom wall 44. The one or more apertures 48 being configured to transport liquid from the trough (and interior of the stack) to the exterior of the first section 30.
In the depicted embodiment, the second section 32 is configured as a substantially cylindrical tube extending along a second longitudinal axis 49 and having a second inner surface 50. The second longitudinal axis 49 may be disposed at an angle θ relative to the first longitudinal axis 34. The second section 32 may have a first end 52 fluidly coupled to the second end 40 of the first section 30. The second section 32 may also have an open second end 54 that terminates to form an exhaust stack discharge port. The open second end 54 may terminate in a plane that is substantially parallel with the first longitudinal axis 34.
The second section 32 may include one or more baffles 56 disposed in the second flow passage 33. The number of baffles 56 and the shape, size, and orientation of the baffles may vary. Any structure(s) capable of protecting the exhaust aftertreatment device(s) 20 from water entering the discharge port of the stack may be used. In the depicted embodiment, the four baffles are arranged in the second section 32, though more or less baffles may be used. Each baffle 56 has a generally elongated body having a first end 58 and a second end 60.
The one or more baffles 56 may be arranged generally parallel to the second longitudinal axis 49 (i.e. at an angle θ to the first longitudinal axis 34) and generally parallel with each other. The second end 60 of each baffle may be generally located proximate the open second end 54 of the second section 32.
Referring to
Referring to
Referring to
The exhaust aftertreatment devices 120 may include for example, a diesel particulate filter (DPF) 124 that includes a DPF substrate 126 at least partially disposed within a DPF housing 128.
The exhaust stack 122 may be configured in a variety of ways. Any structure capable of routing exhaust exiting the power system 110 in a desired direction may be used. The exhaust stack 122 may extend substantially vertically upward or may extend at an angle to vertical. In the depicted embodiment, the exhaust stack 122 includes a first section 130 defining a first flow passage 131 and a second section 132 defining a second flow passage 133. The first section 130 is configured as a substantially cylindrical tube extending along a first longitudinal axis 134 and having a first inner surface 136. The first section 130 may have a first end 38 configured to receive exhaust from the engine 112 and a second end 140 configured to fluidly couple to the second section 132.
The first section 130 may include a liquid drain 142. The liquid drain 42 may be configured in a variety of ways. Any structure capable of diverting and/or catching liquid (such as water) that flows down the first inner surface 136 may be used. In the depicted embodiment, the liquid drain 142 is configured as an annular trough having a bottom wall 144 disposed between a sidewall 146 and the first inner surface 136. One or more apertures 148 may be formed in the first inner surface 136 adjacent the bottom wall 144. The one or more apertures 148 being configured to allow liquid to flow from the trough (and interior of the stack) to the exterior of the first section 130. Thus, the liquid drain 42 catches and diverts the liquid so that the liquid does not continue to flow down the interior of the pipe.
Referring to
In the depicted embodiment, the second section 132 is configured as a substantially cylindrical tube extending along a second longitudinal axis 138 and having a second inner surface 150. The second longitudinal axis 138 may be disposed at an angle θ relative to the first longitudinal axis 134. The second section 132 may have a first end 152 fluidly coupled to the second end 140 of the first section 130. The second section 132 may also have an open second end 154 that terminates to form an exhaust discharge port. The open second end 154 may terminate in a plane that is substantially parallel with the first longitudinal axis 134.
The second section 132 may include one or more baffles 156 disposed in the second flow passage 133. The number of baffles 156 and the shape, size, and orientation of the baffles may vary. Any structure(s) capable of protecting the exhaust aftertreatment device(s) 120 from water entering the discharge port of the stack may be used. In the depicted embodiment, the two baffles are arranged in the second section 132, though more or less baffles may be used. Each baffle 156 has a generally elongated body having a first end 158 and a second end 160. The one or more baffles 156 may be arranged generally parallel with each other. In the depicted embodiment, the two baffles 156 are not parallel to the second longitudinal axis 138. In other embodiments, however, the baffles 156 may be parallel with the second longitudinal axis 138.
Each of the baffles 156 may include a lip 166 extending outward at an angle from the second end 160. In the depicted embodiment, the lip 166 extends in a generally perpendicular direction from the baffle 156. The lip 166 may be configured to collect and channel any liquid on the baffle 156 to the second inner surface 150.
Unlike the embodiment of
The disclosed exhaust stack may be applicable to any power system 10 such as for example an engine, a furnace or any other power source know in the art where precipitation may enter the exhaust stack and cause damage to the exhaust system components, including exhaust after treatment devices. The disclosed exhaust stack may prevent water, which may enter the discharge port of the exhaust stack, from making contact with an exhaust aftertreatment device in the exhaust system, such as a DPF substrate. As a result, the concern of water, in contact with the DPF substrate, freezing and cracking the substrate is eliminated. The operation of exhaust system 14 will now be explained.
Atmospheric air may be drawn into the engine 12, mixed with fuel, and then be combusted to produce mechanical work. Exhaust from the combustion of the air-fuel mixture may contain gaseous compounds and solid particulate matter. The exhaust may be directed from engine 12 to the exhaust system 14, and then directed via the exhaust stack 22 to an exterior of power system 10.
Since, the open second end 54 of the exhaust stack 22 may be directed upward and open to atmosphere, precipitation, sprayed/splashed water or other liquid may enter the exhaust stack 22 and flow downward toward one or more exhaust aftertreatment devices 20.
The baffles 56, however, may be configured to prevent or reduce the amount of liquid that may reach the exhaust aftertreatment device(s) 20. In particular, the one or more baffles 56 may block line-of-sight between the open second end 54 and any inner surface below the liquid drain 42. Thus, the trajectory of any liquid that enters the open second end 54 and does not contact any of the one or more baffles 56 will direct the liquid onto the first inner surface 36 or second inner surface 50 above the liquid drain 42. Therefore, the liquid will flow down the first inner surface 36, be collected by the liquid drain 42, and redirected to the exterior of the exhaust stack 22 via the one or more apertures 48 before reaching the DPF substrate 26, for example.
In addition, in the exemplary embodiment of
In the exemplary embodiment of
Thus, the exhaust stack 22 provides protection to exhaust system components from liquid entering the stack. Furthermore, since the one or more baffles may be angled in =lien with the flow of exhaust exiting the stack, the baffles providing minimal increase in exhaust back pressure.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed dosing system. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed method and apparatus. 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.
