Abstract:
One embodiment is an apparatus including an air-exhaust mixing passageway, a first lip extending into the passageway, a second lip extending into the passageway, a valley intermediate the first lip and the second lip, and an exhaust inlet aperture in flow communication with the flow channel.

Description:
RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application No. 60/876,637 filed Dec. 22, 2006, which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The technical field generally relates to air-exhaust mixing apparatuses. 
       BACKGROUND 
       [0003]    Exhaust gas recirculation (EGR) is used to reduce pollution generated by engines and other combustion devices. With EGR, a portion of the exhaust generated by a combustion reaction is mixed with intake air in order to reduce the amount of pollutants expelled into the atmosphere. Inadequate mixing of the air and exhaust can lead to the creation of increased concentrations of pollutants in the exhaust gas. Various attempts to provide adequate mixing of air and exhaust suffer from a number of drawbacks, disadvantages and shortcomings. There remains a longstanding need for air-exhaust mixing apparatuses which address these issues. 
       SUMMARY 
       [0004]    One embodiment is an apparatus including an air-exhaust mixing passageway, a first lip extending into the passageway, a second lip extending into the passageway, a valley intermediate the first lip and the second lip, and an exhaust inlet aperture in flow communication with the valley. Further embodiments, forms, objects, features, advantages, aspects, embodiments and benefits shall become apparent from the following descriptions, drawings, and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a block diagram of one embodiment of an EGR system. 
           [0006]      FIG. 2  is a side sectional view of one embodiment of an air-exhaust mixer. 
           [0007]      FIG. 3  is a perspective sectional view of the air-exhaust mixer of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0008]    For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
         [0009]    With reference to  FIG. 1 , an EGR system  20  is illustrated in schematic form. System  20  includes an air intake  21 , an air-exhaust mixer  22 , engine intake manifold  23 , engine  24 , exhaust conduit  25 , EGR flow coupling  26 , and EGR valve  27 . Air intake  21  and EGR conduit  26  are flow coupled to air-exhaust mixer  22 . Air-exhaust mixer  22  is flow coupled to engine  24  through engine intake manifold  23 . Engine  24  is flow coupled to EGR valve  27  through exhaust conduit  25 , and EGR valve  27  is flow coupled to air-exhaust mixer  22  through EGR flow coupling  26 . In one embodiment, EGR flow coupling  26  involves the attachment of an EGR valve output to an air-exhaust mixing apparatus. In other embodiments, EGR flow coupling  26  may include one or more intermediate flow passages, conduits or other structures. 
         [0010]    In system  20 , air is supplied through air intake  21 . The supplied air can be filtered, unfiltered, and/or conditioned in other manners. In one embodiment, ambient air is pressurized and sent through an air cooler (not illustrated) before being sent to the air intake  21 . Pressurization can be accomplished, for example, by a turbocharger or supercharger. EGR valve  27  selectably recirculates a portion of exhaust from the engine  24  to air-exhaust mixer  22 . Exhaust which is not recirculated by EGR valve  27  continues through exhaust conduit  25 . In addition, exhaust in system  20  may be utilized to drive a turbocharger and may also be treated by exhaust aftertreatment systems to reduce the emission of pollutants. Air-exhaust mixer assembly  22  mixes exhaust received from EGR valve  27  with air from air intake  21 . The mixture is then supplied to engine  24  through engine intake manifold  23 . In a preferred embodiment, engine  24  is a turbocharged diesel engine. It should be understood that a variety of other types of engines and combustion devices are contemplated by additional embodiments including non-turbocharged diesel engines as well as engines which combust fuels other than diesel. 
         [0011]    With reference to  FIGS. 2 and 3  there is illustrated one embodiment of an air-exhaust mixer  200 . Mixer  200  includes a flow passageway  210  which receives an air flow at intake  212  as indicated by arrow I. As air flow proceeds through flow passageway  210  it encounters lips  220  and  230  which extend into flow passageway  210  to provide a constriction which increases the speed and decreases the pressure of airflow. Valley  240  is positioned intermediate lips  220  and  230  and is substantially open to the region of flow passageway  210  intermediate lips  220  and  230 . 
         [0012]    As illustrated in  FIG. 2 , valley  240  has a generally annular shape with a substantially constant width and depth, and the depth of the bottom surface  242  of valley  240  is greater than that of surface  226  of flow passage  210 . Other embodiments include flow channels which taper from a maximum width near aperture  252  to a minimum width, taper from a maximum depth near aperture  252  to a minimum depth, or both. Further embodiments contemplate flow channels with greater or lesser depths than the illustrated embodiment. Additional embodiments contemplate flow channels which extend over only a portion of the interior of flow passage  210 . Lips  220  and  230  could also extend over only a portion of the interior of flow passage  210  or could have varying heights or widths, though in the illustrated embodiment they have substantially constant dimensions. In a preferred embodiment, lips  220  and  230  and valley  240  are integral portions of a casting. In a most preferred embodiment, substantially the entire body of mixer  200  is a single piece casting. Other embodiments contemplate discrete components which are coupled together to provide lips and an intermediate valley. 
         [0013]    Mixer  200  includes exhaust intake passage  250  which receives exhaust flow from an exhaust source, such as an EGR valve, as indicated by arrows E. The received exhaust flows through exhaust intake passage  250  to exhaust intake aperture  252  and then to valley  240 . Exhaust flows through valley  240  as illustrated by arrow F. As indicated with arrows C 1 , C 2 , C 3 , C 4 , and C 5  exhaust flow exits valley  240  and mixes with the air flow in flow passageway  210 . As indicated by the ellipsis, arrows C 1 , C 2 , C 3 , C 4 , and C 5  are not exclusive routes, rather the mixing flow of exhaust from channel  240  can be essentially continuous along channel  240 . When a lower amount of exhaust is provided to valley  240 , exhaust flow valley  240  could be completed before exhaust reaches the farthest extent of valley  240 . 
         [0014]    A preferred embodiment of mixer  200  includes condensation slot  290 . Moisture and/or particulate which collects in valley  240  can drain via slot  290  to avoid accumulation in valley  240  as well as potential attendant effects such as corrosion. As indicated by arrow P, matter collected in slot  290  is also mixed into the air flow I through passageway  210 . In other embodiments, condensation slot  290  is not present and lip  220  continues through the region in which it is defined. 
         [0015]    The air-exhaust mixture continues to flow through passageway  210 . In a preferred embodiment the mixture flows past central member  226  which is positioned in flow passageway  210 . In other embodiments, central member  226  is not present. The exhaust-air mixture then flows to outlet  214  where it is outlet from mixer  200  as indicated by arrow O. As mentioned above, outlet  214  can be flow coupled to an air intake of an internal combustion engine, or to an air intake manifold. 
         [0016]    While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.