US 3167400 A
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Description (OCR text may contain errors)
Jan. 26, 1965 c FISHER CATALYTIC CONVERTER Filed July 30, 1962 AIDE-2t:
INVENTOR. 62/024 E5 E1 fish E2 conventional mufiier.
United States Patent C) l 3,167,400 CATALYTEC CONVERTER Charles E. Fisher, La Mirada, Calif, assignor to Norris- Thermador Corporation, Los Angeles, Calif., a corporation of California Filed. July 30, 1962, Ser. No. 213,211 4 Claims. (Cl. 23-488) The present invention relates to catalytic converters employed in internal combustion engine exhaust systems for catalytically oxidizing previously unoxidized or only partially oxidized components of the exhaust gases which are harmful when released into the atmosphere, such as hydrocarbons and carbon monoxide, and it relates particularly to a novel catalytic converter construction which f permits a maximum amount of catalyst to be embodied within the converter, which provides relatively even temperature distribution throughout the catalyst bed without damaging hot spots tending to develop, and wherein the parts of the converter are so arranged that bypass channels cannot develop in the catalyst bed through which the exhaust gases would pass untreated, even though a considerable quantity of catalyst material may have been lost due to attrition or other causes.
Although various devices have been proposed for use in vehicles with internal combustion engine exhaust systems for reducing or eliminating smog-forming and other harmful exhaust gas components, such as unburned or partially burned hydrocarbons and carbon monoxide, the most practical and efiicient apparatus for accomplishing this appears to be the catalytic'converter which is employed in the exhaust system as a replacement for the Such a catalytic converter has a catalyst disposed therein, usually a bed of particulate catalyst material, which promotes oxidation of such previously unburned or only partially burned exhaust components, and this chemical action is exothermic, i.e., produces heat.
However, contemporary vehicles with their relatively limited road clearance impose structural limitations on catalytic mufilers or converters, the limitations being such hot spots in the catalyst bed or the development of bypass channels through the bed, and so as to most effective- 1y utilize the catalyst that is present and to avoid localized contamination or poisoning of the catalyst by lead compounds in the exhaust.
It has been found desirable in practice to have the exhaust gases flow vertically, either downwardly or upwardly, through a relatively wide, flat catalyst bed, in order to make the most eflicient use of the catalyst and to avoid poisoning of the catalyst by lead compounds which is likely to occur if the exhaust gases flow longitudinally through a catalyst bed of relatively narrow crosssection. However, prior art vertical flow arrangements in catalytic mufliers of generally flattened form usually resulted in a large waste of the available volume in the case because of excessively large plenum chambers, so that the amount of catalyst employed was seriously restricted.
Another disadvantage of most prior art catalytic mufflers, and particularly those of the vertical flow type, was
that heat transfer within the catalyst bed was relatively slow, resulting in delayed activation of the catalyst during engine warm-up, and because of this poor heat transfer and uneven contact of the exhaust gases with various portions of the catalyst bed, hot spots tended to develop in the catalyst bed, which could cause damage to the catalyst, the muflier case, and possibly surrounding structure of the vehicle.
Further, in many prior art catalytic mufflers, including those of the vertical flow type, it has been found that loss of catalyst due to attrition or other causes provides a bypass or escape paths for the exhaust gases through the muffler Without effective contacting of the catalyst material.
Accordingly, it is an object of this invention to provide a catalytic mufiler wherein the configuration and dimensions thereof may be substantially the same as those of conventional mufflers, and the arrangement of the structure of the catalytic mufller provides for the utilization of a maximum quantity of catalyst material.
Another object of the present invention is to provide a catalytic mufller or converter of the character described wherein the parts thereof are so arranged that bypass channels or escape paths cannot develop in the catalyst bed through which the exhaust gases can pass untreated, even though a considerable quantity of catalyst material may have been lost due to attrition or other causes.
Another object is to provide a catalytic mufiler of the general character described wherein there is a relatively rapid transfer of heat from the input portion of the catalyst bed to the remainder of the bed, thus to accelerate activation of the entire catalyst bed during engine warmup, and wherein the temperature distribution throughout the catalyst bed is maintained relatively uniform during operation and localized hot spots will not tend to develop.
A further object of this invention is to provide a catalytic converter of the aforementioned character wherein there is provided an inlet plenum tube for exhaust gases which is partitioned from an outlet plenum tube by a baflle, the tubes normally being substantially surrounded by the catalyst material and being in close proximity to each other to thereby provide a relatively rapid transfer of heat to the catalyst material, and to also provide a relatively uniform temperature distribution throughout a major portion of the catalytic converter.
A more specific object of this invention is to provide a catalytic converter of the aforementioned character wherein even though the inlet and outlet plenum tubes are in relatively close proximity to each other, the flow path for the exhaust gases from the inlet plenum tube to the outlet plenum tube through the catalyst material is relatively extensive.
A yet further object of this invention is to provide a catalytic converter of the aforementioned character wherein the exhaust gases passing through the converter follow a generally vertical flow path.
A serious problem exists in connection with catalytic converters which is that under certain conditions of engine operation, excessively high concentrations of unburned materials are produced by the engine and passed through the exhaust systems, which results in the production of an excessive amount of heat in the catalytic converter. This excessive heat production in the catalytic converter can darnage the converter case, and could even be damaging to adjacent underside parts of the vehicle, such as brakes or the like. Excessive heat in the converter will also tend to accelerate oxidization of the metal which forms the converter case, thus further tending to reduce the life of the converter.
In view of the immediately preceding problem, it is an objectof thisinventio n' to provide-a catalytie-con-t V 'verter of the aforementioned character wherein excessive heat production inthe catalyst material will'result in actuating al'valving; system to make availableto the "l'exhaustz gasesf a'ipassage through the converter which -Lbypasseslthe. catalyst; until such time as-ihel temperature -;v of ".the. catalyst. returns to acceptable limits. a
lfluntheizobjects;and advantages ofthegpresent'invention rxswill appear during the course'ofzthe tfollowing-rpartnof the: specification; wherein. the details of construction and 19 mode of Operation of a preferredembodiment; are ?de-' -scribedzwitlrlreference. to; the. accompanying drawings, in '-;iwhich: V l j; V l QFIGURE '1.- is a. longitudinal; :vertical. sectional lview,
into outlet plenum tube 30 -from.where they are discharged: However, flowing of the exhaust gases into plenum tube 28 is dependent on the temperature of catalystbeds 38 and 40. L I v Mostgif not'all', catalysts employed in'catalytic converters produce an 'exothermic reaction, when reacting with exhaust gases; i.'e. heat is produced." As a result ;there is an acceptable temperature operating range, and when this range is exceededdue to unusually large quantities of combustible materials being exposed to thecatalyst, damagegto the. catalyst, catalytic converter and vehicle 'ican occur, as. before mentioned. 5 :Wl'len the; temperature range .isfiiexceededrj valving I system :58 .ipreventsnthe; flow of exhaust, gasesintol-inlet p1fenuin tubea28 and instead 1 .'partlyr.in. eleyation,illustratingthe-catalytic converter directs theIeXhaust gasesuthrough .conduit5 2.;thrqugh x:;.togethert with 'a: portionaof the valving systemjfor con- 'open lbutterfly valve 62, and thence into; outlet; or::dis-
trolling the direction of flow of the exhaust gasesthrough charge, plenum .tube 30. a 1' the lconverterii 1 v *Q @Dis'charge plenumztubei islindirect linearjialignment FIGUREfZ is aghorizontalxsectional view; partly in with anopening 64 in rear; wall 26 midway between side -elevation,..taken on. irregular line' 212JofFIGURE 1. 29 Walls 22 and-adjacent the bottom'wallu20, and communi- 7 Q FIGURES isv'a cross-sectional view taken 'online .33 catingt with; opening 641s a vtubular extension;66; which a of: FIGURE 1, showinggttheinlet plenuma tubepartitioned vis rwelded ors t rwi ia torearwall Extenfrom theoutletlplenumiube: and illustrating both Itubes skin-66 is fastened to an exhaust-.gasndischargepipe 68 g? substantially surrounded by catalyst material, i V p 1 by "atypical flange connection 170.- .i'IfhLlS, it "may he :Exhaust :gases. rhaving unoxidiz'ed.and? onlyv "partially 25. seen that 'gasesientering discharge plenum: tubez30..f rom conduit 52 flow directly: out .of'j catalyticzconverter 10 and bypass catalyst beds 38;and"40.
- However, exhaustrgasesqfollowingthe normal'flow path are; received in) inlet plenum 'tube 28,; which isogenerally U -shapedin cr0ss-section'.- The open sideof inlet plenum tube 28 is "closed by top ,walltlin Each .leg .of rinletlplenum oxidized components thereinlare deliveredl-froman ino ternal combustion engine .to catalytic converter- 10 1 through. exhaust pipe 12, .the exhaust. pipe-being fastened to.. catalytic rconverter .19 by atypical flange connection,
14. a. Catalytic :converterll) includes an elongated case 16 3 .:.'.v'v-hi'ch.isroval-shaped in crossts'ection; see. FIGURE 3, a:
aandwhich embodiesarelatively. flattopi wall 18; a relalube, 23.111215 an outwar yfi g 711116113011 it tivelylafiat; bottom? wall 20, ra pair or substantially semi gwhich l l y fas en in Plenum lube/I23 to case 1 .cylindricalsideWalls J22, alfront orforward 4wall-24, PI= 1Y by W ng- ,Theayb gh of ;inlet:';plenu1n and-a'rear orback wall 26. i a tube 28 is-adjacent to horiz ontalfbafile plate .321,
'Disposedlin;case 16 isia lperforate inletplenum tube f'EXh as flQW y lm inl t. lp enumztube. 123 iinto '18. which :is partitioned-from 1a perforate outlet plenum b t ys b 88 1 ;andjsin mfi Width of ba l tube 30,.by. ashorizontalbafiieplate32. lBafi'l'e plate 32 pla 324 e tha tt erwidt tween t e-l of is supported in case 16 substantially midway between i l P I l b 1 @Xh g v za leirflq red t0 L1OPL18 andtbottdmswall 210.b'y..vertical struts33=-and by aswm i-a r zcnt l tw ll as. a fi t alrflowjpath in v c'onnec.tion .with. end :wallsl24 and 26. Plenum tubes 28 V l tOPaSSVaTQlmd bafile Plate 1324111141 into Outlet Plenum and 30 ,are in vertical alignmenufand together with baflle b i h h hPF Q 3l i Llhsfl laplate 32; thepIenum; tubes arecoextensivein length with I 0 t srw t fi i b an ia yw l t q -;case"; 16. lAdditionallygplenumtubes 28 :and 30 'are 1 2 F b 'i t U- hm l @IOSSsection, .1..equallysspacedinwardly:from -both sidelwalls-22 so as 5 nv r W hQPPFm ifie s n' 'Qlq fi t y-b ltoverticallyi'partition casel'1'6 into a pair oflsubstantially', tom Wall W I lY d l fi t r Q Iidentical-compartments(Stand36,each of: which has ivQsubstantially-thesame volume as: the other and each of V V Y ,which isafilled with ;a catalyst material, preferably in M??? tube fl as m. r b fig a ez3?- particulate form,sso as to provide a pair of spaced catalyst50 T 33 b arsb a lQ il lal li r -shedsl38tandz40,-}whlich-inay beconsider ed-asingle catalyst r iip "Pl um i i a other" and to '.-'i. bed,-all of,-.which lwill hereinafter be described in more 1 ligfflgplatev szithat heat fromllQtnexhaulstggase/s n -;.-extensivedetail; I 1' w l .7 .v t 1 :Eorward wall 24 ofr case lot-encloses" the forward end lfelfredl F Lb i Y Q 3 a d-W1 9i l mlm ab t l and lot-compartments 34 and 36, land rear wall-26encloses 552 i ileat 5 l l l g and t w s iigml F a ilheirearaend of the .compartme nts so as to prevent the; i f qg t l tP 3i .i i na b loss of catalyst material. Howeven the forwardwall I pauselthgplenum n? a fit lfifl 38 I has A a Pair of yerticauyx align-edjjopeningsl L42 :afid and are coextensive arelativelytuniforrnteniperatnre is a neck 46 which divides intoupper andllower Exhaust-gases angering Ouflgtor dlssharge Plenum torn wall 20; preferably by.weldinggand the bightof outleg arelemployed to fasten outlet plenum tube 30 to boti'ng inlet; plenum tube 2311s efficiently vconducted or transa conduits .50 and 5 2, respectively, which are joined at a a common ,wall, 54, the conduits .50 :and 52 being welded:
ore otherwisefastened to the, forward wall 24, with upper vconduit 50 in communication with plenum tube 28 and tube'l30 from catalyst beds- 38-iaind40 flowfrom plenum 'tubeifitl through extension tube dandintdldischarge 'pipe 68 where they are discharged ltovtheatmosphere.
lowerlconduit52 in communication with plenum tube 30.
Theflow/of exhaust gases into conduits 50' or 52'is controlled-by aiyalving system 58, which includes abutterfly valve 60 disposed in conduit "50 and a butterfly wvalvefildisposed in conduit 52,valving system 58 being .hereinafterdescribe'd in .moreextensive detail. r
I A feature of particular significanceis'the-novel arrangement of catalyst beds 38 and 40; There can be as much as about 50% loss of catalyst material due to attrition or other causes, and still the exhaust gases fijowing from inlet plenum tube '28 tooutlet plenumftube 30 will be Underznormal temperatureconditions-in the catalyst thoroughly treated to -oxidize those unoxidiged or only partially oxidized components of thejexhaust: gases. For instancegthe level of catalyst beds 38 and 4 0 may fail to'approximately the levelof baiiieplate ifaZ xfWith the catalystgbeds at this rlevel, exhaust gases must still. flow through" the catalyst" material in" order to enter outlet plenum tube 30, and with the catalyst beds at this level no bypass or escape paths are available which would enable the exhaust gases to enter outlet plenum tube 30 with- I out being treated. By having the exhaust gases flow downwardly through the converter rather than upwardly, the particulate catalyst tends to be packed in the lower part of the converter case, even if part of the catalyst has been lost, thus further insuring against development of bypass channels through the catalyst beds.
As previously mentioned, valving system 58 is responsible for controlling the direction of flow of the exhaust gases. This valving system includes a diaphragm actuator 76 which is supported at the forward end of case 16. Actuator 76 is connected to the intake manifold 78 of the engine through vacuum conduit 80, and vacuum conduit 80 has a valve 82 therein which is mounted on case it? of catalytic converter 10. Valve 82 includes a temperature sensing probe 84 which extends into catalyst bed 38 substantially midway in the flow path of the exhaust gases from inlet plenum tube 28 to outlet plenum tube 30. Therefore, although probe 84 is located to one side of case 16, it is in a position to obtain an average sampling of the temperature occurring within catalyst bed 38, and
the temperature of catalyst bed 38 is also representative of the temperature of catalyst bed 40.
Temperature sensing probe 84 may be any suitable I thermo-mechanical device capable of actuating valve 82,
' the normal operating range or within the normal operating range, the temperature sensing probe 84 holds valve 82 in its open position so that the partial vacuum condition within intake manifold 78 is communicated through vacuum conduit 80 to diaphragm actuator 76, and with valve 82 in this condition the exhaust gases flow into upper conduit 50 and into inlet plenum tube 28. However, when the temperature in catalytic converter it) rises above a predetermined value, sensing probe 84 will cause valve 82 to close, so that the intake manifold 78 does not communicate with diaphragm actuator '76 through vacuum conduit 80, and with valve 82 in this condition the flow of exhaust gases will be diverted through lower conduit 52 and directly into and through outlet plenum tube 30. A shaft 86 is slidably connected to diaphragm actuator 76, and'connected to a free end of shaft 86 is a linkage system 88 which is connected to butterfly valves 60 and 62.
Butterfly valve 62 will render conduit 52 closed to exhaust gases and butterfly valve 60 will render conduit 50 open to exhaust gases when the temperature of the cat- .alytic converter is below or within the acceptable temperature operating range and valve 82 is open, with the result that exhaust gases will flow into inlet plenum tube 28, through catalyst beds 38 and 40, thence into outlet plenum tube 30 from where they flow into discharge pipe 68 and then into the atmosphere. However, when'the temperature of catalyst beds 38 and 40 exceeds the predetermined operating value, valve 82 will close in response to the temperature rise which results in diaphragm actuator 7 6 causing shaft 86 to actuate the linkage system 88 to cause butterfly valve 60 to render passage 50 closed, and butterfly valve 62 to open passage 52. The exhaust gases will then enter outlet plenum tube 30 and be discharged therefrom in the aforementioned manner.
While the instant invention has been shown and described herein in what is conceived to be the most praetical and preferred embodiment, it is recognized that dedetails disclosed herein, but is to be accorded the full scope of the claims.
Having described my invention, what I claim as new and desire to secure by Letters Patent is:
l. A catalytic converter for treating exhaust ingredients produced by an internal combustion engine, comprising: a case defining a chamber having opposed ends; an inlet plenum tube having an elongated perforated portion in said chamber extending substantially from end to end thereof; an outlet plenum tube having an elongated perforated portion in said chamber and extending substantially from end to end thereof in parallel and overlapping relation to said elongated perforated portion of said inlet plenum tube and in close proximity thereto; a heat conductive baffle plate between and parallel to said portions and extending substantially the entire length of said portions, said baffle extending laterally a substantial distance beyond the sides of said portions and terminating in opposed edges spaced inwardly from opposite sides of said chamber; and a bed of particulate catalyst material substantially filling said chamber and encompassing substantially all surfaces of said portions exposed Within said chamber and said bafile plate whereby to'define an extended flow path for exhaust gases from said inlet portion to said outlet portion, through said material and around said baiile while providing a short heat conductive path from the region adjacent one portion to the region adjacent the other portion through said bafi'le plate.
2. A catalytic converter as defined in claim 1 wherein said plenum tube portions and said baille plate are in direct heat conductive contact substantially throughout their lengths.
3. A catalytic converter as defined in claim 1 wherein said plenum tube portions and said bafile plate are in direct contact substantially throughout their lengths and define a partition across said chamber between said opposite sides.
4. A. catalytic converter as defined in claim 1 wherein said chamber is of generally flattened oval shape in transverse cross section, having generally flat top and bottom wall portions; said baflle plate being positioned generally centrally between said top and bottom wall portions and said opposed edges being spaced from said sides a distanee about the same as the distance between said b-afile plate and said top and bottom wall portions.
References Cited by the Examiner UNITED STATES PATENTS 1,875,024 8/32 Kryzanowsky 23-2S8.3 2,488,563 11/49 Sills 23288.3 2,614,647 10/52 Bryant 181-57 2,747,976 5/56 Houdry 23-4883 2,785,962 3/57 Ruth 23--288.3 2,787,119 4/57 Giambruno 23-288.3 2,898,202 8/59 Houdry et al 23288.3 2,928,492 3/60 Nelson 23-288.3 2,991,160 7/61 Claussen 23288.3 3,024,593 3/62 Houdry 23-288.3 3,050,935 8/62 Eastwood 23288.3 3,054,664 9/62 Purse 23288.3 3,083,084 3/63 Raymond 23288.3 3,086,839 ,4/63 Bloch 23288.3 3,090,677 5/63 Scheitlin et al. 32 288.3 3,094,394 6/63 lnnes et al 23-288.3 3,097,074 7/63 Johnson 23-2883 FOREIGN PATENTS 448,850 6/36 Great Britain.
MGRRIS O. WOLK, Primary Examiner.
GEORGE D. MITCHELL, Examiner.