Abstract:
Disclosed herein is a method for reducing internal combustion engine contaminate and additive particulate matter from a particulate filter the method including accessing the filter and entraining particulate matter in a fluid stream. Further disclosed herein is an internal combustion engine particulate filter system including a canister, a filter media mounted in said canister and an access opening in said canister. Yet still further disclosed herein is a method for determining condition of a particulate filter in situ including establishing a vacuum value for a clean particulate filter in situ, establishing a vacuum value for a used particulate filter in situ; and comparing the established value for the clean filter versus the used filter.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application is a U.S. non-provisional application based upon and claiming priority of U.S. provisional application Ser. Nos. 60/359,971 filed Feb. 27, 2002 and 60/363,776 filed Mar. 13, 2002, which are hereby incorporated by reference. 

   BACKGROUND 
   Particulate filters are employed in internal combustion engine exhaust systems where particulate escape to the environment is not desirable. One such system is that of a diesel exhaust system. In such system, a combustion source produces some particulate matter and that matter is filtered out of the exhaust gas stream from that combustion source before exhaust gas therefrom is released to atmosphere or another system. The hydrocarbon particulate is periodically removed by means of a high temperature regeneration process that is controlled by the vehicle engine computer, and that occurs when needed, automatically while the vehicle is in use. In addition to the hydrocarbon particulate matter other contaminants, such as zinc dithiophosphate, from the engine lubricating oil, and cerium, which is sometimes added to the fuel to aid regeneration, is trapped in the filter system. Since the automatic regeneration process does not remove these materials, they gradually plug the pores in the filter. Such particulate filter systems lose efficiency with usage due to contaminate, and additive particulate matter buildup. Arrangements and methods associated with the reduction of costs and time involved in cleaning and/or replacement of such particulate filters is desirable. 
   SUMMARY 
   Disclosed herein is a method for reducing contaminate, and additive particulate matter in a diesel particulate filter, including accessing the filter and entraining contaminate, and additive particulate matter in a fluid stream. 
   Further disclosed herein is a diesel particulate filter system including a canister, a filter media mounted in said canister and an access opening in said canister. 
   Yet further disclosed herein is a low cost particulate filter system having access for particulate removal, the system including a canister, a filter mounted in the canister, a flange retainer without a seal and a sleeve disposed in said canister and configured to inhibit particulate leakage from and flange retainer. 
   Still further disclosed herein is a low cost particulate filter system having access for contaminate, and additive particulate removal including a canister, a sub canister positionable in said canister, a filter mounted in said sub canister and a single flange retainer closing said canister and mounting said sub canister. 
   Yet still further disclosed herein is a method for determining condition of a particulate filter in situ including establishing a vacuum value for a clean particulate filter in situ, establishing a vacuum value for a used particulate filter in situ; and comparing the established value for the clean filter versus the used filter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be described, by way of an example, with references to the accompanying drawings, wherein like elements are numbered alike in the several figures in which: 
       FIG. 1  is a schematic cross-sectional view of a canister supporting a catalyst substrate and a particulate filter; 
       FIG. 2  is a schematic cross-sectional view of an alternate canister supporting a catalyst substrate and a particulate filter; 
       FIG. 3  is a schematic cross-sectional view of an o-ring seal arrangement; 
       FIG. 4  is the illustration of  FIG. 3  with a v-clamp securing the components thereof; 
       FIG. 4A  is a view of a commercially available v-clamp; 
       FIG. 5  is a schematic partial cross-sectional view of an alternate particulate filter support arrangement; 
       FIG. 6  is a schematic cross-sectional view of an alternate canister with access openings and plugs; 
       FIG. 7  is a view similar to  FIG. 6  intended to illustrate the “normal operation” flow of fluid through the system and particulate buildup; 
       FIG. 8  is the  FIG. 7  view with a plug removal and a negative pressure conduit extended into the canister; 
       FIG. 9  is a plan view of a commercially available plug; 
       FIG. 10  is a cross-sectional view of a commercially available plug; 
       FIG. 11  is a view of a commercially available tool to install the plug of  FIGS. 9 and 10 ; 
       FIG. 12  is an alternate common available plug; and 
       FIG. 13  is a schematic view of a vacuum value check system. 
   

   DETAILED DESCRIPTION 
   It is to be appreciated that although several of the drawing figures herein include a catalyst substrate, this is for contextual purposes and for one embodiment of the invention as disclosed herein. It is not germane to that which is claimed whether or not the catalyst substrate is illustrated or included in the canister in which the filter is supported. If the drawings were modified to omit the catalyst, the function and construction of that disclosed herein will remain unchanged. Notwithstanding the foregoing, some of the drawings do include the catalyst substrate as one embodiment of the invention as it is employed with a diesel catalytic converter and particulate filter system. 
   Further, it is noted that a catalyst substrate can in some conditions trap particulate matter and in such condition be, in effect, a filter. For this reason, it is to be understood that the device and method described herein can be used to remove particulate matter from a catalyst in the same way as described for a filter hereafter. 
   Referring to  FIG. 1 , one of skill in the art will recognize a construction similar to the existing art, having a canister  14  in three sections a, b and c affixable together by two sets of paired flanges  8   a,    8   b.  One will also recognize an intumescent or non-intumescent support material  18  supporting a particulate filter  20 . Distinct from the existing art however is that at flanges  8   a,    8   b  no seals are evident. Seals are expensive and in this embodiment are avoided. Tubular sleeve  22  is affixed in a sealed manner to canister section  14   a  and extends beyond an end  24  thereof. The extended region  26  of sleeve  22  is configured to engage material  18  and may be of frustoconical shape to make such engagement centrally of material  18 . The configuration is meant to and is effective in preventing particulate matter from migrating to flanges  8   a  thus preventing leakage therefrom regardless of the absence of a seal at flange  8   a.  A seal is not necessary at  8   b  because the particulate has already been filtered out of the stream passing through canister  14  by the time that stream contacts flanges  8   b.  If a seal is desired at the exit end of the particulate filter, a similar tubular sleeve can be used to seal the exit flange. 
   In an alternate embodiment, one of the flange pairs  8  is completely eliminated. Additionally, and as a consequence of elimination of one of the flange pairs, canister section  14   b  has also been eliminated. Canister section  14   a  and  14   c  remain, in slightly distinct dimensions from the previous embodiment. In this embodiment, ( FIG. 2 ) a sub canister  28  is employed to support particulate filter  20  and material  18 . Sub canister  28  is made stable within canister  14  by the provision of a flange  30  which may be fully or partly annular. The flange may be constructed by compressing the ends of a tubular structure or by any other means including welding an annular flange onto the O.D. of the tubular structure. Flange  30  is received and captured in flange  8  during manufacture or reassembly and maintained in position thereby. To effect this condition it will be recognized that flanges  8  include a keyway  32  formed about ½ in each flange side. The flanges  8  include a seal  34  that may be of the metal o-ring type and are fastened together by any number of means including separate fasteners such as bolts. Each of the flanges  8  are affixed to the canister sections  14   a / 14   c  by welding, illustrated at beads  36 . This construction facilitates accessing filter  20 , repositioning of the same and cleaning of the same. 
   Referring to  FIGS. 3 and 4  and back to  FIGS. 1 and 2 , an alternate seal construction for canister  14  is illustrated. In the embodiment of  FIGS. 3 and 4 , canister  14  is configured to accept an o-ring. The canister sections are then secured with a commercially available “V-clamp”  40 .  FIG. 4   a  is a view of the commercially available V-clamp. 
   In yet another embodiment, referring to  FIG. 5 , an o-ring seal is avoided by the provision of a metal-to-metal seal structure. Canister section  14   a  and canister section  14   c  each include a flared meeting edge  42 . The flare is about 45 degrees in an outwardly direction. A sub canister  44 , similar to the sub canister discussed above, includes a distinct annular or part annular flange  46 . The flange  46  extends outwardly from the sub canister  44  at about a  45  degree angle such that two angled faces  48 ,  50  are created. It is these faces  48 ,  50  when pressed against inside surfaces  52 ,  54  of meeting edges  42  that creates the metal-to-metal seal. In order to effect the seal a flange pair  56 ,  58 , having an angled surface  60 ,  62 , each of which is complementary to meeting edges  42 , is fastened together with fasteners such as bolts  64  to compressively join the above discussed components. 
   Each of the foregoing embodiments allows access to the filter  20  for removal, repositioning, cleaning, replacement, etc. These are desirable attributes and are less expensive than prior art configurations but do still require relatively costly hardware. 
   Alternately, referring to  FIG. 6 , a canister  70  is configurable to facilitate cleaning of filter  20 . As illustrated the filter is mounted conventionally.  FIG. 6  includes openings related to cleaning of the filter. 
   Opening  72  is closeable by a plug which may be of a number of different types. One type of plug employable is a sheet metal fill plug  74  (detail views are available in  FIGS. 9 and 10 ). These are reliable plugs while remaining easily removable. The structure of plug  74  is, referring to  FIGS. 9 and 10 , a single piece of sheet metal which has been stamped to create a top hat type appearance with brim  84  and crown  86 . Crown  86  comprises a domed top  88  and an annular connector  90  extending between top  88  and brim  84 . In use, a tool  92  illustrated in  FIG. 11  is employed to expand annular connector  90  while plug  74  or  76  is installed in opening  72 ,  78  respectively, which permanently locks the plug in place. The plug may then only forcibly and destructively be removed. The tool is commercially available and is known to the art as a “plug expander tool”. Referring to  FIG. 12 , an alternate plug is illustrated which comprises a bar  94  which may be square in cross-section, with a threaded hole in the center as illustrated, and which is to be positioned inside opening  72 ,  78  and a cover  96  intended to cover opening  72 ,  78 . A bolt  98  and washer  100  are employed as shown to urge cover  96  against canister  70  for a tight seal. This plug is removable without destruction thereof. With a plug  74  removed, opening  72  is large enough to allow insertion of a negative pressure conduit. Negative pressure may be created by any means. 
   In one embodiment ( FIGS. 7 and 8 ) plug  74  is removed solely and fluid flow whether the fluid be gas or liquid such as air, water, solvent, etc. through filter  20  is induced simply by drawing fluid through conduit  80 . Where more direct positive pressure fluid, again whether that fluid be gas or liquid such as air, water, solvent, etc., is desired, plug  76  is removed from opening  78 , downstream of filter  20 . Positive pressure from any source may then be introduced either generally through opening  78  or by insertion of a positive pressure conduit  82  to direct the positive pressure flow to discrete areas of the filter  20 . 
   Referring back to  FIG. 6 , several embodiments are considered. The first is the provision of a negative pressure through a negative pressure conduit  102  to the normally upstream end  104  of filter  20 . Fluid flow in this embodiment is caused solely by the negative pressure at upstream end  104  or by negative pressure at  104  in addition to a positive pressure applied through conduit  80  from a “normal operation” exhaust exit (not shown). This embodiment is further illustrated in  FIGS. 7 and 8  in clear detail where particulate matter  110  is illustrated collecting in filter  20  during normal operation of the combustion source and the exhaust system. 
   With negative pressure conduit  102  inserted into conduit  70  ( FIG. 8 ) through opening  72  and located in a discrete area of upstream end  104  of filter  20 , particulate matter, contaminant and additive material  110  is illustrated being removed from filter  20 .  FIG. 8  further illustrates one negative pressure supply arrangement which is fully understandable by one of skill in the art simply by viewing the drawing. A hose  112  is connected to a filter  114  in a housing  116  which is then connected to a venturi  118  creating vacuum by shop air flowing through conduit  120 . 
   Alternatively, still referring to  FIG. 6 , the negative pressure conduit  102  having been attached to canister  70  at the opening  72  and providing a negative pressure to upstream end  104 , is supplemented by directed pressurized fluid through conduit  82  inserted into canister  70  through opening  78 . For filters  20  proving to be difficult to clean, the ability to direct pressurized fluid as to a discrete area of the “normal operation” downstream end  106  of filter  20  while locating negative pressure conduit  102  in the same discrete area on upstream end  104  is quite effective. 
   Alternatively, still referring to  FIG. 6 , the positive pressure may be pulsated to provide additional momentary air velocity and volume. This pulsated flow can be directed to a discrete area of the “normal operation” downstream end  106  of filter  20 , or alternatively by connecting the pulsating air pressure source directly to opening  78 . A plug added to the exhaust pipe behind the filter maybe used to prevent loss of flow out the vehicle exhaust pipe. In this case the negative pressure conduit  102  would still be attached to canister  70  at the opening  72  providing a negative pressure to upstream end  104 , to remove the contaminate. 
   The method discussed herein is benefited by a knowledge of when the filter  20  which is in need of cleaning, and has been sufficiently cleaned. This can be accomplished by the manufacturer of the target system by providing a “known clean” negative pressure numerical value at opening  72 . This value is employable to determine how “plugged” the filter  20  is by connecting a vacuum gauge to the downstream end of the system and removing plug  74  from opening  72 . A numerical value of vacuum is then obtainable based upon a fixed negative pressure. If the vacuum numerical value is larger than “known clean” then particulate matter has impeded flow through filter  20 . A threshold value would also be provided by the manufacture of the system for a cleaning action as described above. The manufacture would also provide a means of calibrating such a system so that it would be useable with the varying amount of flow induced by various vacuum sources. Likewise, after a cleaning operation, the vacuum gauge may again be connected to test the effect the cleaning operation has had. It should be understood that in at least some of the foregoing embodiments, plug  76  would need to be reinstalled prior to testing. This testing operation, whether before or after cleaning, is schematically illustrated in  FIG. 13  where the combustion source is  130 , filter unit is  132 , muffler unit is  134  and tailpipe end is  136 . Attached to the schematically illustrated system is a vacuum gauge  138  and venturi vacuum device  140  with shop air supply  142 . 
   While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.