WO2013055361A1

WO2013055361A1 - Egr air-exhaust mixer

Info

Publication number: WO2013055361A1
Application number: PCT/US2011/056359
Authority: WO
Inventors: Jack Morais; Robert Z. Olszewski
Original assignee: International Engine Intellectual Property Company, Llc
Priority date: 2011-10-14
Filing date: 2011-10-14
Publication date: 2013-04-18

Abstract

An EGR air-exhaust gas compact mixer is provided, having an air intake to supply air, and an exhaust gas intake to supply exhaust gas. The mixer includes a mixer housing having a cavity and a mixing part positioned within the cavity. The mixing part includes a plurality of non-diverging and non-converging dispersion nozzles positioned radially therein, and a plurality of air flow channels positioned between the dispersion nozzles. The dispersion nozzles disperses exhaust gas, while the air flow channels disperses intake air, providing a mixture of air and exhaust gas prior to return to the engine.

Description

EGR AIR-EXHAUST MIXER

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates generally to air-exhaust mixers used in exhaust gas recirculation, and more specifically to a compact air-exhaust mixer for easy installation on existing or new engines.

BACKGROUND OF THE INVENTION

[0002] Exhaust gas recirculation (EGR) is used to reduce pollution generated by engines and other combustion devices. With EGR, a portion of the exhaust gas generated by the engine is mixed into the air intake in order to reduce the amount of pollutants expelled into the atmosphere. Typical air-exhaust mixer assemblies, such as venturi type mixers, occupy a large amount of space so as to ensure that the exhaust gas and intake air are completely mixed. Incomplete mixing of the air and exhaust gases can lead to the creation of increased concentrations of pollutants in the exhaust gas. To ensure complete mixing of the gases, venturi type mixers typically have long mixing cavities. Other types of mixers have mixing cavities with large lengths, widths and/or heights in order ensure complete mixing of the gases. These large mixers in turn makes retrofitting of air-exhaust mixers to engines quite expensive, because the plumbing of the engine has to be extensively modified in order to accommodate the large air-exhaust mixers. Another problem is that venturi type mixers significantly reduce the pressure of the mixed gas supplied to the engine.

[0003] Therefore, there is need for a more compact air-exhaust mixer having a simplified structure and small air-exhaust mixing components that is relatively inexpensive to manufacture and install, and that minimizes gas pressure drop across the mixer.

SUMMARY OF THE INVENTION

[0004] There is disclosed herein an improved air-exhaust mixer unit and method of mixing intake air and recirculated exhaust gas prior to returning the mixture to the engine, which avoids disadvantages of prior devices, while affording additional structural and operating advantages.

[0005] In an embodiment of the present invention, an air-exhaust mixer includes an air intake to supply air and an exhaust gas intake to supply exhaust gas. A mixer housing is connected to the air intake and the exhaust gas intake, the mixer housing including an interior cavity for receiving a mixing part. The mixing part includes an interior with a plurality of dispersion nozzles disposed radially therein, and a plurality of air flow channels positioned between each dispersion nozzle. The air-exhaust mixer also includes a exit elbow integrally connected to the mixer housing downstream from the dispersion nozzles and air flow channels.

[0006] In another embodiment of the present invention, an air-exhaust mixer unit is disclosed including an air intake to supply air and an exhaust gas intake to supply exhaust gas. A mixer housing is connected to the air intake and the exhaust gas intake, the mixer housing including an interior cavity for receiving a mixing part. The mixing part includes a plurality of generally curved dispersion nozzles disposed radially therein, having an opening directed downstream from the air intake. The mixing part also includes a plurality of air flow channels positioned between each dispersion nozzle. An exit elbow having a mixing zone is integrally connected to the mixer housing, and is fluidly connected to the engine for return of the air-exhaust gas mixture to the engine.

[0007] In yet another embodiment of the present invention, the dispersion nozzles have both a non-diverging and non-converging configuration in a first direction.

[0008] In another embodiment of the present invention, a method for mixing exhaust gas with intake air in an exhaust gas recirculation device is disclosed.

The method includes the steps of providing an air intake to supply air and providing an exhaust gas intake to supply exhaust gas. The method also includes providing an air-exhaust mixer housing connected to the air intake and the exhaust gas intake, the mixer housing having an interior cavity for receiving a mixing part having a plurality of non-diverging dispersion nozzles disposed radially therein, and a plurality of air flow channels positioned between each dispersion nozzle. A exit elbow having a mixing zone is integrally connected downstream from the mixer housing, and facilitates mixing the intake air from the air flow channels with the exhaust gas from the dispersion nozzles prior to return to the engine.

[0009] These and other aspects of the invention may be understood more readily from the following description of certain embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.

[0011] FIG. 1 is a perspective view of the EGR air-exhaust mixer of the present invention.

[0012] FIG. 2a is an assembled view of the mixer housing of the present invention.

[0013] FIG. 2b is a sectional view of the mixer housing of the present invention.

[0014] FIG. 2c is a cross-sectional view of the mixing part positioned within the mixer housing of the present invention.

[0015] FIG. 3a is an exploded view of the mixer housing and EGR exit elbow.

[0016] FIG. 3b is a sectional view of the dispersion nozzles and air flow channels of the mixing part of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0017] While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated.

[0018] Referring now to FIG. 1, there is an air-exhaust mixer unit 10 of the present invention. Generally, and as know in the art, the air-exhaust mixer unit 10 of the present invention is used in conjunction with the exhaust gas recirculation (EGR) system of an engine or other combustion device. In one embodiment, the engine may be a diesel engine. The EGR system includes and EGR valve 12, EGR housing 14 and EGR connector 16. In the present invention, the air-exhaust mixer unit 10 includes the EGR valve 12 and housing 14, which are coupled to the engine through an EGR connection 16 for receiving and circulating exhaust gas through the mixer housing 18. The mixer housing 18 is connected to an air intake source 20 and an EGR exit elbow 22. These structures and their functions will now be described in further detail in conjunction with the figures.

[0019] Referring to FIGs. 2a-c, there is illustrated an embodiment of the air-exhaust mixer 10, mixer unit, or portions thereof. The mixer 10 includes the mixer housing 18, which is integrally connected to an air intake source 20, such as an intake throttle, and an exhaust gas source, such as the EGR valve 12 located within the EGR housing 14. Intake air is supplied to the mixer 10, and specifically the mixer housing 18, through the intake air source 20. It should be appreciated that the supplied air can be filtered, unfiltered, and/or supplied in another manner as generally known in the art. Exhaust gas is provided to the mixer housing from the engine through the EGR connector 16 to the EGR valve 12, which recirculates a portion of the exhaust gas into the air-exhaust mixer housing 18, while the remaining exhaust exits the system (not shown). The recirculated exhaust gas and intake air are mixed through the mixer housing 18, and the exhaust gas/air mixture supplied back to the engine through the EGR exit elbow 22. The air intake source 20 and the exhaust gas source 14 may be connected to the mixer housing 18 in a know manner, such as through screws or bolts.

[0020] As shown in FIG. 3a, the mixer housing 18 includes a cavity 24 for receiving a mixing part 26. When assembled, the mixing part 26 is slid into the cavity 24 of the mixer housing 18, and can be secured in a suitable known manner, including through an annular lip or an elastomeric seal, or other securing method. A elastomeric seal or O-ring (not shown) may also be provided between the intake air source 20 and the mixer housing 18 in order to better seal the connection.

[0021] As shown in FIGs. 2a-2c, the mixing part 26 includes an interior space 26a having a plurality of dispersion nozzles 28 positioned around the circumference of the interior space in both a non-diverging and non-converging configuration in a first direction. As will be described, the dispersion nozzles 28 direct the flow of recirculated exhaust gas. Preferably, the dispersion nozzles 28 have a curved shape with an opening 28a directed toward the exit elbow 22, for release of the exhaust gases downstream from the flow of the intake air. It should be understood by one skilled in the art that the dispersion nozzles can have any shape useful in the present invention for dispersion of the exhaust gas. The curved shape of the dispersion nozzles 28 of the present invention permits for construction of a relatively compact mixing part 26, providing more options for installation of the air-exhaust mixer 10 into existing and new engines. In addition, it is believed that the curved shape of the dispersion nozzles 28, in conjunction with the non-diverging/non-converging configuration of the nozzles within the mixing part 26, provides for more turbulent flow of the exhaust gas and therefore better mixing with the intake air.

[0022] The mixing part 26 includes an interior annular exhaust passage 30, best seen in FIG. 2c. The exhaust passage 30 connects to the exhaust intake source 14, receiving the recirculated exhaust gas through an opening 14a therein. The dispersion nozzles 28 are fluidly connected to the exhaust passage 30, such that the exhaust gases circulate through the exhaust passage 30 and exit out through the dispersion nozzles 28, as described. [0023] As shown in FIG. 3b, the mixing part 26 includes a plurality of air flow channels 32. Specifically, the air flow channels 32 are positioned between each of the dispersion nozzles 28. The air flow channels 32 may be provided in both a non-diverging and non- converging configuration in a first direction within the mixing part 26. Optionally, the air flow channels 32 may be any suitable shape for use in the present invention. The air flow channels 32 are fluidly connected to the air intake source 20, and direct the flow of intake air from the air intake source in a first direction through the mixing part 26. As previously discussed, the shape and configuration of the dispersion nozzles 28 permits improved mixing of the exhaust gas and intake air exiting from the dispersion nozzles and the air flow channels 32, respectively.

[0024] The air-exhaust mixer 10 also includes a EGR exit elbow 22, having an interior mixing cavity 34 (FIG. 2b). The EGR exit elbow 22 is integrally connected to the mixer housing 18, preferably forming a single unit with the mixer housing. In the present embodiment, the exit elbow 22 has a curved shape; however, the shape and construction of the exit elbow, as well as the manner in which it may be attached to the mixer housing 18, may be modified depending on requirements for the engine. The exit elbow 22 is fluidly connected to the engine, so that the air/exhaust gas mixture can be returned to the engine. As was noted, it is believed that the non-diverging, non-converging configuration of the curved dispersion nozzles 28 create a turbulent release of the exhaust gas for mixing with the intake air from the air flow channels 32. In addition, it is believed that the curved mixing cavity 34 of the mixing elbow 22 further contributes to mixing of the air and exhaust gases, also creating an improved air/exhaust gas mixture.

[0025] The present invention also provides a method for creating a mixture of exhaust gas with intake air for use in an exhaust gas recirculation device of an engine. Referring to FIGs. 2b and 2c, the arrows A represent the flow path of the intake air, while the arrows E represent the flow path of the exhaust gas. Intake air is supplied from the air intake source 20, while exhaust gas is provided through the exhaust gas source 14. An air-exhaust mixer housing 18 is connected to the air intake source 20 and the exhaust gas source 14, the mixer housing having an interior cavity 24 for receiving a mixing part 26. The mixing part 26 includes an interior annular exhaust gas passage 30 connected to a plurality of dispersion nozzles 28 having a curved or arcuate shape, disposed radially therein, and a plurality of air flow channels 32 positioned between each dispersion nozzle. [0026] In the present method, intake air A is supplied from the air intake source 20, flows into the mixer housing 18 and through the air flow channels 32. At the same time, exhaust gas provided from the exhaust gas source 14 enters the interior annular exhaust passage 30 of the mixing part 26, through an opening 14a, following the path indicated by E. The exhaust gas then enters the dispersion nozzles 28, where it is released in a first direction to mix with the intake air flowing through the air flow channels 32. The dispersion nozzles 28 are provided within the mixing part 26 in both a non-diverging and non-converging

configuration. The intake air and recirculated exhaust gases mix together and enter the EGR exit elbow 22, where the air/exhaust gas mixture is directed back into the engine.

[0027] The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants' contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.

Claims

CLAIMS What is claimed is:

1. An air-exhaust mixer comprising:

an air intake to supply air;

an exhaust gas intake to supply exhaust gas;

a mixer housing connected to the air intake and the exhaust gas intake, the mixer housing having an interior cavity;

a mixing part having a plurality of dispersion nozzles disposed radially therein, the mixing part being disposed within the cavity of the mixer housing;

a plurality of air flow channels positioned between each dispersion nozzle; and,

an exit elbow integrally connected to the mixer housing downstream from the dispersion nozzles and air flow channels.

2. The mixer of claim 1 wherein the mixing part includes an interior annular exhaust gas passage fluidly connected to the exhaust gas intake.

3. The mixer of claim 2, wherein the annular exhaust gas passage is fluidly connected to each of the dispersion nozzles.

4. The mixer of claim 1 , wherein the plurality of dispersion nozzles have a non- diverging configuration in a first direction.

5. The mixer of claim 4, wherein the plurality of dispersion nozzles have a non- converging configuration in a first direction.

6. The mixer of claim 1 , wherein the dispersion nozzles have a generally curved shape.

7. The mixer of claim 6, wherein the dispersion nozzles have an opening for directing the exhaust gas downstream from the air intake.

8. The mixer of claim 1, wherein the air flow channels are fluidly connected to the air intake.

9. The mixer of claim 8, wherein the air flow channels are parallel to the direction of air flow therethrough.

10. The mixer of claim 1, wherein the exit elbow is integrally connected to the mixer housing

11. The mixer of claim 10, wherein the exit elbow includes an interior mixing cavity.

12. The mixer of claim 11 , wherein the mixing cavity receives a mixture of intake air and exhaust gas for return to the engine.

13. An air-exhaust mixer unit for providing a mixture of intake air and recirculated

exhaust gas to an engine, the mixer unit comprising:

an air intake to supply air;

an exhaust gas intake to supply exhaust gas;

a mixing part having a plurality of non-diverging dispersion nozzles in a first direction and air flow channels disposed radially therein, the mixing part located within the cavity of the mixer housing; and,

an exit elbow integrally connected to the mixer housing downstream from the dispersion nozzles and air flow channels, wherein the exit elbow includes a mixing cavity for simultaneously receiving a mixture of air from the air flow channels and exhaust gas from the dispersion nozzles.

14. The mixer unit of claim 13 wherein mixing part includes a interior annular exhaust gas passage fluidly connected to the exhaust gas intake and the dispersion nozzles.

15. The mixer unit of claim 13, wherein the dispersion nozzles have a generally curved shape.

16. The mixer unit of claim 13, wherein the plurality of dispersion nozzles are provided in a non-converging configuration in a first direction.

17. The mixer unit of claim 13, wherein the air flow channels are positioned between each of the dispersion nozzles.

18. The mixer unit of claim 17, wherein the air flow channels direct the air flow in a parallel direction therethrough.

19. The mixer unit of claim 13, wherein the exit elbow is fluidly connected to the engine.

20. A method for creating a mixture of exhaust gas with intake air for use in an exhaust gas recirculation device of an engine, the method comprising the steps of:

providing an air intake to supply air;

providing an exhaust gas intake to supply exhaust gas;

providing an air-exhaust mixer housing connected to the air intake and the exhaust gas intake, the mixer housing having an interior cavity;

providing a mixing part for insertion into the cavity of the mixer housing, the mixing part including a plurality of dispersion nozzles disposed radially therein; providing a plurality of air flow channels positioned between each dispersion nozzle;

providing an exit elbow having a mixing zone, the exit elbow integrally connected downstream from the mixer housing;

mixing the air from the air flow channels with the exhaust gas from the dispersion nozzles creating an air-exhaust gas mixture within the mixing zone.

21. The method for creating a mixture of claim 20, wherein the method further includes the step of returning the air-exhaust gas mixture to the engine.

22. The method for creating a mixture of claim 20, wherein the method further includes providing an interior annular exhaust gas passage within the mixing part, the passage circulating the exhaust gas into the dispersion nozzles. The method of creating a mixture of claim 20, wherein the plurality of dispersion nozzles are provided in a non-diverging configuration.

The method of creating a mixture of claim 23, wherein the plurality of dispersion nozzles are provided in a non-converging configuration.