Muffler apparatus with filter trap and method of use

• US 4,851,015 A
• Filed: 08/21/1987
• Issued: 07/25/1989
• Est. Priority Date: 08/21/1987
• Status: Expired due to Term

• Current Assignee: Donaldson Company Incorporated
• Original Assignee: Donaldson Company Incorporated
• Inventors: Steinbrueck, Edward A., Wagner, Wayne M., Hoppenstedt, Bruce B., Flemming, Douglas E.
• Primary Examiner(s): Spitzer, Robert
• Application Number:
  US07/088,055
• Time in Patent Office: 704 Days
• Field of Search: 55/96, 55/267, 55/270, 55/272, 55/276, 55/283, 55/286-288, 55/523, 55/DIG. 5, 55/DIG. 30, 55/20, 181/231, 181/255, 181/258, 181/269, 60/311-313, 60/320, 60/324, 29/163.5 F, 29/243.52, 29/511, 29/520
• US Class Current: 95/15
• CPC Class Codes: F01N 2230/02 Exhaust filters
• CPC Class Codes: F01N 2310/12 Granular material
• CPC Class Codes: F01N 2330/06 Ceramic, e.g. monoliths
• CPC Class Codes: F01N 2350/02 Fitting ceramic monoliths in a metallic housing
• CPC Class Codes: F01N 2350/04 with means compensating thermal expansion
• CPC Class Codes: F01N 2350/06 with means preventing gas flow by-pass or leakage
• CPC Class Codes: F01N 2410/04 during regeneration period, e.g. of particle filter
• CPC Class Codes: F01N 2450/02 Fitting monolithic blocks into the housing
• CPC Class Codes: F01N 2470/02 Tubes being perforated
• CPC Class Codes: F01N 3/0211 Arrangements for mounting filtering elements in housing, e.g. with means for compensating thermal expansion or vibration
• CPC Class Codes: F01N 3/023 using means for regenerating the filters, e.g. by burning trapped particles by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/027 using electric or magnetic heating means
• CPC Class Codes: F01N 3/032 during filter regeneration only
• CPC Class Codes: F01N 3/0335 with exhaust silencers in a single housing
• CPC Class Codes: F01N 3/30 Arrangements for supply of additional air control, e.g. using by-passes or variable air pump drives, F01N3/22
• CPC Class Codes: F01N 9/002 of filter regeneration, e.g. detection of clogging
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y10S 55/05 Methods of making filter
• CPC Class Codes: Y10S 55/10 Residue burned
• CPC Class Codes: Y10S 55/30 : Exhaust treatment
• CPC Class Codes: Y10T 29/49934 : by axially applying force

Abstract

Muffler apparatus for reducing both sound and particulates from exhaust gases from an engine. The apparatus includes resonating chambers, flow distribution structure and a cellular ceramic core filter module. Filter regeneration mechanism includes a heating element for heating the carbon on the inlet end of the ceramic core to combustion temperature. Particulate ignition resulting in regeneration occurs when combustion air is provided; in alternate embodiments, combustion air first flows through a preheater system. A processor unit with particular logic controls the apparatus.

Claims

1. A method for removing oxidizable particulates from a filter trap in a muffler apparatus, said muffler apparatus including a housing having an inlet, an outlet, and a fluid flow passage for exhaust gases leading from said inlet upstream to said outlet downstream, said fluid flow passage including a reactive acoustic element, said muffler apparatus also including in said fluid flow passage means for filtering the particulates from the exhaust gases, said muffler apparatus still further including means for heating an inlet end of said filtering means and means for blowing air through said heating means toward the inlet end of said filtering means, said muffler apparatus yet further including valve means for controlling the flow of exhaust gases to said housing, said muffler apparatus also including first means for sensing a first pressure differential upstream of said filtering means and a second pressure differential across said filtering means and first means for comparing said first and second pressure differentials to a predetermined value to identify a first triggering relationship, said particulates having a combustion temperature, said muffler apparatus also including a second means for sensing one of temperature of said heating means, temperature of fluid between said heating means and said filtering means and temperature of said filtering means inlet end, second means for comparing said temperature relative to a predetermined temperature less than the combustion temperature to identify a second triggering relationship, and third means for comparing said temperature relative to the combustion temperature to identify a third triggering relationship, said muffler apparatus also including means for timing a predetermined period, said method comprising the steps of:

identifying the first triggering relationship;

closing with said valve means flow of exhaust gases to said housing after said first triggering relationship;

turning on said heating means after said valve means closing step;

starting said air blowing means after said valve means closing step;

identifying said second triggering relationship;

stopping said air blowing means after said second triggering relationship;

identifying said third triggering relationship;

starting said air blowing means after said third triggering relationship;

starting said timing means after said third triggering relationship;

stopping said heating means during the timing of said timing means;

stopping said air blowing means after said timed period; and

opening with said valve means flow of exhaust gasses to said housing after said timed period.

2. The method in accordance with claim 1 wherein said first step starting said air blowing means starts said air blowing means at a reduced flow and said second step starting aid air blowing means starts said air blowing means at a significantly increased flow.

3. A particulate filter module, comprising:

a ceramic filter element having opposite ends and a longitudinal side region therebetween;

a rigid housing having a wall enclosing said side region of said filter element, said wall being formed so as to leave a space between it and said side region, said wall having inwardly turned ends to longitudinally compress said filter element;

means, within said space, for intumescing so that said ceramic filter element is held in transverse compression by said;

wall and

means for sealing said intumescing means in said space between said filter element and said wall.

4. Muffler apparatus for reducing both sound and particulates from exhaust gases from an engine, comprising:

a housing having an inlet, an outlet, and a fluid flow path leading from said inlet upstream to said outlet downstream;

a reactive ocoustic element within said housing along said fluid flow path, said element attenuating the sound of said exhaust gases;

means, within said housing along said fluid flow path, for filtering the particulates from said exhaust gases, said filtering means including a ceramic filter element having an inlet end;

means for regenerating said ceramic filter element; and

means for controlling said regenerating means.

5. Apparatus in accordance with claim 4 wherein said regenerating means includes means for primarily radiantly heating the inlet end of said filter element.

6. Apparatus in accordance with claim 5 wherein said regenerating means also includes means for blowing combustion air through said heating means toward the inlet end of said filter element.

7. Apparatus in accordance with claim 6 including means, within said housing, for preheating said combustion air upstream from said heating means.

8. Apparatus in accordance with claim 7 wherein said housing inlet includes a pipe with a downstream end and a plurality of openings upstream from said downstream end, said apparatus further including a chamber within said housing and about said inlet pipe, one of said openings providing fluid communication between said pipe and said chamber, said combustion air blowing means including means for inletting combustion air into said chamber, said preheating means being within said chamber.

9. Apparatus in accordance with claim 8 wherein said preheating means includes a heating element and said chamber includes a granular material between said pipe and said heating element, said granular material storing heat from said heating element and requiring the combustion air to diffuse therethrough to be heated thereby.

10. Apparatus in accordance with claim 9 wherein said combustion air blowing means includes an air source and wherein said combustion air inletting means includes a wall having a plurality of openings therein distributing combustion air from said source into said granular material.

11. Apparatus in accordance with claim 6 wherein said housing includes a baffle separating said housing into adjacent chambers, said controlling means including first means for sensing a first pressure differential across said baffle and a second pressure differential across said ceramic filter element, said controlling means also including first means for comparing said first and second pressure differentials relative to a predetermined value to identify a first triggering relationship, said controlling means also including first means for starting said heating means when said first comparing means has identified said first triggering relationship.

12. Apparatus in accordance with claim 11 wherein said controlling means includes second means for starting said air blowing means.

13. Apparatus in accordance with claim 12 wherein said controlling means includes second means for sensing one of temperature of said heating means, temperature of fluid between said heating means and said ceramic filter element, and temperature of said ceramic filter inlet end, said particulates having a combustion temperature and said controlling means further including second means for comparing said one temperature relative to a predetermined temperature less than the combustion temperature to identify a second triggering relationship, said controlling means still further including first means for stopping said air blowing means when said second comparing means has identified said second triggering relationship.

14. Apparatus in accordance with claim 13 wherein said controlling means further includes third means for comparing said one temperature relative to said combustion temperature to identify a third triggering relationship, said controlling means also including third means for starting said air blowing means after said third comparing means has identified said third triggering relationship, said controlling means also including means for timing a predetermined period beginning after said third comparing means has identified said third triggering relationship, said controlling means further including second means for stopping said air blowing means at the end of said period.

15. Apparatus in accordance with claim 5 wherein said heating means includes an electrical heating element embedded in a ceramic plate, said ceramic plate having an opening therein to pass exhaust gases therethrough.

16. Apparatus in accordance with claim 4 wherein said ceramic filter element is cylindrical and has a central portion at said inlet end including and surrounding the axis, said apparatus further including means, within said housing along said fluid flow path, for deflecting exhaust gases outwardly away from said central portion, thereby forming a ring outside said central portion having a greater concentration of particulates, said housing inlet including a pipe with a downstream end, said pipe including a plurality of openings upstream from said downstream end, said deflecting means including an end cap fastened to said pipe at said downstream end to prevent fluid flow from said end thereby requiring fluid entering said pipe to exit through said openings.

17. Apparatus in accordance with claim 4 wherein said controlling means include valve means for selectively directing said exhaust gases one of through said housing and away from said housing, said controlling means including means for sensing a first pressure differential upstream from said ceramic filter element and a second pressure differential across said ceramic filter element, said controlling means also including means for comparing said first and second pressure differentials relative to a predetermined value to identify a triggering relationship, said controlling means further including means for shifting said valve means from directing said exhaust gases through said housing to directing said exhaust gases away from said housing when said comparing means has identified said triggering relationship.

18. Apparatus in accordance with claim 17 wherein said valve means includes a two-way, two position valve.

19. Apparatus in accordance with claim 17 wherein said valve means includes a three-way, three position valve.

20. Muffler apparatus for filtering particulates from exhaust gases from an engine, comprising:

a housing having means upstream for inletting said exhaust gases and means downstream for outletting said exhaust gases, said housing including spaced-apart ends and a wall enclosing an interior space extending between said ends, said housing also including a baffle attached to said wall to divide said interior space into first and second chambers, said inletting means including an inlet pipe passing through and supported by one of said ends and said baffle, said inlet pipe having inlet and outlet ends and an interior therebetween, said inlet pipe further having first perforations to provide fluid communication between the interior of said inlet pipe and said first chamber and second perforations to provide fluid communication between the interior of said inlet pipe and said second chamber, said inlet pipe also having valve means for controllably closing said inlet end and a closure member closing said outlet end so as to direct fluid from the interior of said inlet pipe outwardly through said second perforations;

a ceramic filter element mounted in said housing, said ceradic filter element having an inlet end and an outer surface, said outer surface being sealed with respect to the wall of said housing so as to force fluid to pass through said ceramic filter element;

means, mounted in said housing, for heating a portion of said ceramic filter element;

means for blowing air into said first chamber so that the air must flow through said first perforations into the interior of said inlet pipe before being directed outwardly through said second perforations and past said heating means to said ceramic filter element; and

means for controlling said valve means, said heating means and said air blowing means, said controlling means including first means for sensing a first pressure differential upstream from said ceradic filter element and a second pressure differential across said ceramic filter element, said controlling means also including first means for comparing a ratio of said first and second pressure differentials relative to a predetermined value to identify a first triggering relationship, said controlling means also including means for shifting said inlet pipe valve means closed after said first comparing means has identified said first triggering relationship, said controlling means further including means for starting said heating means after said first comparing means has identified said first triggering relationship, said controlling means still further inducing second means for sensing one of temperature of second heating means, temperature of fluid between said heating means and said ceramic filter element, and temperature of said ceramic filter inlet end, said controlling means also having second means for comparing said temperature relative to a predetermined combustion temperature to identify a second triggering relationship, said controlling means also including means for starting and means for stopping said air blowing means at times between said first and second triggering relationships, said controlling means further including means for timing a predetermined period after said second triggering relationship and a means for stopping said heating means and said air blowing by the end of said period, said controlling means also including means for opening said inlet pipe valve means after said period;

whereby the exhaust gases flow through said housing from the inlet end of said inlet pipe to said outletting means.

21. Muffler apparatus for reducing both sound and particulates from exhaust gases from an engine, said apparatus comprising:

a muffler-filter device including a housing having an inlet, an outlet, and a fluid flow path leading from said inlet to said outlet, said housing containing a first reactive acoustic element, said housing also containing means for filtering the particulates from the exhaust gases, said filtering means including a ceramic filter element, said device including means for regenerating said ceramic filter element;

a muffler including a second reactive acoustic element;

first means for fluidly communicating between said engine and said muffler-filter device, said first communicating means including a first valve;

second means for fluidly communicating between said engine and said muffler, said second communicating means including a second valve; and

means for controlling said regenerating means and said first and second valves, said controlling means positioning one of said first and second valves open and the others closed.

22. Muffler apparatus for reducing the sound of exhaust gases from an engine, said apparatus comprising:

first and second muffler devices, each of said first and second duffler devices having a reactive attenuation chamber, said first muffler device including means for filtering particulates from the exhaust gases, said filtering means including a ceramic filter element;

means for periodically regenerating said filtering means, said regenerating means including means for heating one end of said filter element and means for blowing combustion air through said heating means toward said filter element;

valve means for Controlling the flow of exhaust gases to said first and second muffler devices;

means for connecting said first and second muffler devices, said valve means and said engine in fluid communication so that said first and second muffler devices are in a parallel combination; and

means for controlling said regenerating means and said valve

23. Apparatus in accordance with claim 22 wherein said valve means includes a three-way, three position valve, said valve in said first position placing said engine in fluid communication with both of said first and second muffler devices, said valve in said second position placing said engine in fluid communication with only said first muffler device, said valve in said third position placing said engine in fluid communication with only said second muffler device.

24. Apparatus in accordance with claim 22 wherein said connecting means includes a pipe from said engine splitting into a pair of legs, said valve means including a two-way, two position valve in each leg of said pair of legs of said pipe.

25. A method for making a particulate filter module, said module including a ceramic filter element having opposite ends and a side region therebetween, said module including a housing formed from a cylindrical metallic sheet which encloses the side region of the filter element and has inwardly turned ends to retain said ilter element therebetween, said module further including a heat resistant material between said filter element and said housing and sealing means between said heat resistant material and said inwardly turned ends, said method comprising the steps of:

wrapping the side region of said ceramic filter element with said heat resistant material;

slipping said wrapped ceramic filter into said housing;

placing said sealing means at ends of said heat resistant material; and

forming said inwardly turned ends on said housing to compress a portion of said sealing means between said ceramic filter element and each of said inwardly turned ends of said housing.

26. The method in accordance with claim 25 including prerolling a metallic sheet before slipping said wrapped ceramic filter into it and after slipping said wrapped ceramic filter into said prerolled metallic sheet squeezing said rolled sheet to a predetermined cylindrical dimension and welding facing edge portions together.

27. A method for making a particulate filter module, said module including a ceramic filter element having opposite ends and a side region therebetween, said module including a cylindrical metallic housing enclosing the side region of the filter element and having inwardly turned ends to retain said filter element therebetween, said module further including an intumescent resistant material between said filter element and said housing and sealing means between said intumescent material and said inwardly turned ends, said method comprising the steps of:

wrapping the side region of said ceramic filter element with said intumescent material;

slipping said wrapped ceramic filter into said housing;

placing said sealing means at ends of said intumescent material;

forming said inwardly turned ends on said housing to compress a portion of said sealing means between said ceramic filter element and each of said inwardly turned ends of said housing; and

heating said module so that said intumescent material intumesces.