Abstract:
An in-line filter assembly for filtering engine exhaust gases utilized by turbocharged internal combustion engine systems. The filter assembly includes an external housing having a lower housing section and an upper housing section. The upper housing section further includes an air inlet port and an air outlet port. A filter unit for decontaminating the exhaust stream is positioned below the air inlet port. An interior chamber is in communication with the outlet port and surrounds the filter unit. A spring positioned directly beneath the filter unit stabilizes the filter unit within the chamber and urges the filter unit upward into sealing engagement with the inlet port. The lower housing section also includes a sump for collecting contaminants captured by the filter unit.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates in general to filtration devices for automotive applications, and more specifically to a filtration assembly for removing liquid and solid contaminants from exhaust gases in a turbocharged air stream that is used to cool the bearing of the turbocharger. 
     BACKGROUND OF THE INVENTION 
     An internal combustion engine requires oxygen for the fuel utilized by the engine to be effectively combusted. Oxygen is typically supplied to such engines by drawing ambient air from the external environment into the engine. While the air drawn into the engine provides the necessary oxygen, ambient air also contains a large quantity of nitrogen. The high temperatures generated by internal combustion engines cause this nitrogen to react with any unused oxygen and results in the formation of nitrogen oxides [NO X ], which are considered to be one of the main environmental pollutants emitted by vehicle engines. 
     Exhaust gas recirculation (EGR) was developed as a means for reducing NO X  emissions by recycling a portion of the exhaust gases generated by a vehicle&#39;s engine back into the air intake of the engine. Exhaust gases contain much less oxygen than ambient air and by mixing the exhaust gases with fresh air drawn into the engine, the overall oxygen consumption of the engine is reduced. Providing the engine with less oxygen decreases the combustion temperature and, consequently, reduces the amount of pollutants emitted by the vehicle. 
     The inclusion of turbochargers in the engine systems of vehicles such as diesel cars and trucks is commonplace. More recently developed turbochargers include bearings that do not require external lubrication i.e., oil. Such bearings typically include a polymeric surface coating that can be damaged or degraded by physical contact with oil or other hydrocarbons. Degradation of this polymeric surface decreases the performance and effectiveness of such bearings and can reduce the overall performance and longevity of the turbocharger. 
     Oil in the form of an aerosol and/or vapor, as well as solid particulate matter, is often found in the exhaust gases generated by internal combustion engines. Thus, in vehicles that utilize both exhaust gas recirculation systems and turbochargers with oil-free bearings, the possibility exists that certain contaminants present in the re-circulated exhaust gases can damage the turbocharger&#39;s bearings. Therefore, the need exists for a filtration device that will safely and effectively remove oil aerosols and other contaminants from exhaust gases re-circulated to a turbocharger that is included as part of a vehicle&#39;s engine system. 
     SUMMARY OF THE INVENTION 
     The present invention provides a filter assembly for filtering engine exhaust utilized by exhaust gas recirculation systems installed in turbocharged internal combustion engine systems. This filter assembly is mounted in-line in a vehicle&#39;s turbocharger bearing cooling system and removes hydrocarbon aerosols, vapors, and particulate matter that is potentially damaging to the bearings used in certain turbochargers. 
     An exemplary embodiment of this invention includes an external housing having a lower housing section and an upper housing section. These sections are typically permanently attached to one another by adhesive means, but are detachable from one another in certain embodiments. The upper housing section further includes an air inlet port for allowing the exhaust stream to enter the filter assembly and an air outlet port for allowing the exhaust stream to exit the filter unit. A filter unit for decontaminating the exhaust stream is positioned below the air inlet port. In an exemplary embodiment, the filter unit includes a micro-glass fiber filter element for filtering the exhaust gas, and a means for providing structural support to the micro-glass fibers. Other filter media are compatible with the filter unit of the present invention. An interior chamber is in communication with the outlet port and surrounds the filter unit. Filter exhaust gases exit the filter unit, enter the chamber, and are expelled from the assembly through the air outlet port. 
     Additionally, an exemplary embodiment includes a spring positioned directly beneath the filter unit for stabilizing the filter unit within the chamber and for urging the filter unit upward into sealing engagement with the inlet port. The spring also serves as a bypass system that allows air to pass directly from the inlet port to the outlet port if the filter element becomes clogged or plugged. An end cap positioned directly beneath the filter unit and directly on top of the spring further stabilizes the filter unit within the housing. The lower housing section also includes a ring, indentation, or groove for stabilizing the spring within the housing while upper housing section further includes a collar formed around the base of the air inlet port for stabilizing the filter unit within the housing. The lower housing section also includes a sump for collecting contaminants captured by the filter unit. 
     Further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated into and form a part of the specification, schematically illustrate an exemplary embodiment of the invention and, together with the general description given above and detailed description of the preferred embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is a cross-sectional side view of the filter assembly of the present invention showing the various internal components of the assembled device. 
         FIG. 2  is a perspective view of the filter assembly of the present invention showing the appearance of the assembled device. 
         FIG. 3  is an exploded perspective view of the present invention showing the various component parts of the filter assembly. 
         FIG. 4  is a schematic block diagram showing various components associated with an typical internal combustion engine, a typical exhaust gas recirculation system, and the filter assembly of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference Numerals 
     
         
           10  filter assembly 
           12  upper housing section 
           14  lower housing section 
           16  inlet port 
           18  outlet port 
           20  collar 
           22  first joining member 
           24  second joining member 
           26  filter unit 
           28  end cap 
           30  spring 
           32  chamber 
           34  sump 
           50  engine system 
           52  air filter 
           54  turbocharger 
           56  compressor 
           58  turbine 
           60  intercooler 
           62  engine 
           64  intake manifold 
           66  combustion chambers 
           68  exhaust manifold 
           70  air bearing 
           72  EGR cooler 
           74  valve 
       
    
     With reference to  FIGS. 1-3 , and according to an exemplary embodiment of the present invention, filter assembly  10  includes a substantially cylindrical external housing, a filter unit  26 , and an internal support mechanism. The external housing component further includes an upper housing section  12  and a lower housing section  14  which are detachably connected at and by first joining member  22  and second joining member  24 . Filter unit  26  resides within the housing of filter assembly  10  and is secured within chamber  32  by an internal support mechanism comprising collar  20 , end-cap  28 , and spring  30 . In the exemplary embodiment shown in  FIG. 1 , collar  20  is formed integrally with upper housing section  12 . Preferably, spring  30  sits in a ring, groove, indentation, or similar structure (not shown) in lower housing section  14  and provides pressure to end-cap  28  sufficient to keep filter unit  26  secured in-place within chamber  32 . Although this placement of spring  30  is preferred, other placements of the spring are possible. In an alternate embodiment, spring  30  sits atop the filter unit and urges the filter unit downward into end-cap  28 . 
     As stated above, filter assembly  10  is designed for use with turbocharged internal combustion engines that utilize exhaust gas recirculation (EGR), which is a process known in the art for reducing dangerous engine emissions from vehicles.  FIG. 4  shows filter assembly  10  installed in-line in a turbocharged diesel engine utilizing EGR. As will be appreciated by those skilled in the art, engine  50  comprises a number of engine components that are connected to one another by a series of ducts through which the air stream flows.  FIG. 4  is a general schematic showing the placement of the present invention within the engine system and is not intended to show all of the components and subcomponents typical of internal combustion engines. 
     As illustrated in  FIG. 4 , the air required for combustion is drawn into engine system  50  through air filter  52  (arrow “A”). The filtered air stream then flows from air filter  52  into the compressor  56  of turbocharger  54  (arrow “B”), exits compressor  56 , and flows to intercooler  60  (arrow “C”). Upon exiting intercooler  60 , the air flow splits into two separate paths. A portion of the air flow (arrow “D”) is directed to intake manifold  64  which forms part of engine  62 . Intake manifold  64  directs the air to combustion chambers  66  where it is mixed with fuel and combusted. The products of combustion or “exhaust gases” exit combustion chambers  66  and enter exhaust manifold  68  which directs the exhaust gases out of engine  62  and into the turbine  58  of the turbocharger. Turbine  58  is also referred to in the art as a charger or supercharger. The exhaust gases flow through the line labeled as arrow E in  FIG. 4 , and a portion of said gasses is then directed through valve  74  into optional EGR cooler  72  (arrow “F”). After exiting optional EGR cooler (arrow “G”) the gases recombine with the fresh air intake (arrow “B”). As also shown in  FIG. 4 , the portion of the airflow that does not flow toward engine  62  is directed toward filter assembly  10  (arrow “H”). After passing through filter assembly  10 , this portion of the airflow is directed through air bearing  70  (arrow “I”). 
     Recirculated exhaust gases contain a variety of contaminants including gaseous pollutants such as hydrocarbons, nitrogen oxides, carbon monoxide, as well as particulate matter. The particulate matter typically comprises both a dry, solid carbonaceous fraction and a soluble organic fraction which is present in the diesel exhaust as either a vapor phase or a liquid phase, or both. The exhaust also contains particles such as zinc and phosphate (resulting from lubricating oils), calcium, magnesium and silicates (resulting from engine coolant) and iron (resulting from engine wear) all of which combine to form exhaust ash. Any or all of these contaminants can potentially damage the turbine and its components because turbochargers that utilize oil-less bearings with polymeric surfaces are particularly susceptible to damage by such contaminants, especially hydrocarbons. 
     To remove the potentially damaging contaminants from re-circulated exhaust gases, filter assembly  10  is mounted in-line between intercooler  60  and air bearing  70 . Gases enter filter assembly  10  through inlet port  16  (see  FIGS. 1-3 ) and pass through filter unit  26 . In an exemplary embodiment, filter unit  26  is a coalescing filter comprising a substantially tube-shaped filter element made from fine micro-glass fiber. Filter unit  26  traps particulate matter directly within its matrix and causes aerosols to agglomerate or “coalesce” on the surface of the filter material. As the aerosols coalesce on the filter element, droplets of oil or other substances eventually form and become heavy enough to drop off of filter unit  26  and fall into sump  34  where they are retained for the period filter assembly  10  is in operation. Once the contaminants have entered sump  34 , they are effectively prevented from re-entering the exhaust air stream. 
     Exhaust gases exit the filter unit and enter chamber  32  which surrounds filter unit  26 . As shown in  FIG. 1 , the exemplary embodiment includes a chamber  32  that is physically larger than the portion of the interior of filter assembly  10  occupied by filter unit  26 . In other embodiments of this invention, filter unit  26  and chamber  32  are symmetrical with respect to one another such that if viewed in cross section, both halves of the interior of filter assembly  10  would appear substantially equal in size. Other spatial configurations may be utilized without diminishing the effectiveness of the filter unit. 
     In the event that filter unit  26  becomes blocked or other inoperative in a manner that prevents the exhaust gases from passing through the filter, spring  30  provides a bypass mechanism that allows the gases to pass through filter assembly  10  unfiltered. In normal operation, spring  30  is axially interposed between lower housing section  14  and end cap  28  to urge filter unit  26  upward, or into sealing engagement with collar  20 . If a restriction or blockage occurs in filter unit  26 , air pressure will build in inlet port  16  and urge the entire filter unit downwardly to compress spring  30 . This movement of the filter unit establishes a bypass passage allowing inlet port  16  to communicate directly with outlet port  18  by way of chamber  32 . In this manner the inlet port and outlet port are in communication without proceeding through filter unit  26 . In an exemplary embodiment, spring  30  exerts of force of approximately twenty-five (25) pounds; however, this force is exemplary and is should not be construed in a limiting sense. 
     The outer housing of filter assembly  10  may be manufactured from plastic, polymer, metals such as steel or aluminum, or any other sufficiently rigid material. In one embodiment, upper housing section  12  and lower housing section  14  are glued or otherwise permanently affixed to one another resulting in a filter assembly may be removed and disposed of after it has reached the end of its useful life. In another embodiment, the two housing sections are detachably held together by snap means or other means of attachment resulting in a filter assembly that may be removed, opened, cleaned and/or re-conditioned with replacement parts, and re-installed in the vehicle&#39;s EGR system. 
     While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as exemplification of preferred embodiments. Numerous other variations of the present invention are possible, and is not intended herein to mention all of the possible equivalent forms or ramifications of this invention. Various changes may be made to the present invention without departing from the scope of the invention.