US 3811845 A
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United States Patent [191 Nakamura 1111" 3,811,845 1451 May 21, 1974 1 1 VEHICLE EXHAUST CONTROL EQUIPMENT  Inventor: HarutokiNakamura,Toyonaka,
Japan  Assignee: Matsushita Electric Industrial Co.,
Ltd., Osaka, Japan  Filed: July 19, 1971  Appl. N0.: 163,939
 Foreign Application Priority Data 3,134,457 5/1964 Marcellus 55/010. 30
3,189,563 6/1965 Havel 23/288 R 3,495,950 2/1970 Barber et a1 23/288 F 3,380,810 4/1968 Hamhlin 23/288 F 3,385,915 5/1968 Hamling 264/5 2,674,521 4/1954 Houdry 23/288 R 3,154,388 10/1964 Purse 23/288 F FOREIGN PATENTS OR APPLICATIONS 631,368 6/1936 Germany 23/288 F 1,443,886 5/1966 France 23/288 F Primary Examiner-James H. Tayman, Jr. Attorney, Agent, or Firm-Stevens, Davis, Miller & Mosher 57 ABSTRACT A casing is divided into a plurality of small parallel catalyst chambers into which are packed mesh-like catalysts whose carriers are fabrics woven from glass fibers.
1 Claim, 10 Drawing Figures JIIIIII 111/1 1 11 LII/Ill II I1 PAIENTEBmzuw v I 181L845.
'SHEEIIBFS PRIOR ART PRIOR ART F/G. 3a
- PRIOR ART FIG. 3b
VEHICLE EXHAUSTCONTROL EQUIPMENT BACKGROUND OF THE INVENTION The present invention relates to generally an atmospheric pollution control equipment and more particularly a vehicle exhaust control equipment.
One of the objects of the present invention is to provide an improved vehicle exhaust control equipment of the type using the catalysts to convert the pollutants such as. carbon monoxide, unburnt hydrocabons and nitrogen oxides in the exhaust gases from an automobile engine into harmless gases.
Another object of the present invention is to provide an improved vehicle exhaust control equipment which is very effective in eliminating the pollutants in the exhaust gases for the purpose of atmospheric pollution control.
Another objectof the presentinvention is to provide an improved vehicle exhaust control equipment which may effectively dissipate the heat produced in the catalytic oxidations so that the'thermal breakdowns of the catalysts may be prevented and the long service life of the equipment may be ensured.
Another object of the present invention is to provide an improvedvehicle exhaust control equipment which may be manufactured in a simple manner at less cost.
SUMMARY OF THE INVENTION increase silica contents.
According another feature of the present invention, the small catalyst chambers are of box-shaped and disposed on both sides of an exhaust gas introduction passage connected to an inlet of the casing.
According to another feature of the present invention, the equipment has a cylindricalcasing which is di-* vided into more than two small catalyst chambers by a plurality of doughnut-shaped partition walls, and the mesh-like catalystsare wound around the exhaust gas introduction passage.
According to another feature of the present invention, the last of the plurality of partition disks has no center aperture so as 'to close the exhaust gas introduction passage, and the last chamber defined between this last partition disk and the side wall on the side of the discharge end ofthe cylinder is not packed with the mesh-like catalysts and is used as a chamber for discharging the exhaust gases, which have been made in contact with the mesh-like catalysts, into a discharge pipe connected to a muffler or the like.
According to another feature of the present invention, the exhaust gas introduction passage is gradually reduced in cross. section toward the discharge end of the casing.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a block diagram of a system for cleaning or purifying the exhaust gases from an automobile engine;
FIG. 2 is a diagrammatic sectional view of the prior art vehicle exhaust control equipment designated by 2 in FIG. 1;
FIG. 3a is a diagrammatic longitudinal sectional view of another prior type vehicle exhaust control equipment;
FIG. 3b is a cross sectional view thereof;
FIG. 4a is a diagrammatic longitudinal sectional view of a first embodiment of the present invention;
FIG. 4b is a perspective view thereof with a top cover removed;
FIG. 5 is a diagrammatic longitudinal sectional view of a second and fourth embodiments of the present invention;
FIG. 6 is a diagrammatic longitudinal view of a third and fifth embodiments of the present invention;
FIG. 7a is a diagrammatic longitudinal sectional view ofa sixth embodiment of the present invention; and
FIG. 7b is a perspective view thereof with a part of the casing wall being broken away.
DESCRIPTIONDF THE PREFFERD EMBODIMENTS In FIG. 1 is shown in block diagram the prior art vehicle exhaust control equipment for eliminating or purifying the pollutants included in the vehicle exhaust gases. The exhaust gases from an automobile engine 1 is introduced through an exhaust pipe into an exhaust control equipment 2, where the exhaust gases are purified. The purified gases are introduced into a muffler 3 where the sound of the gases is attenuated and the temperature of the gases is reduced, andthe exhaust gases are finally discharged into the surrounding atmosphere through an exhaust pipe 4.
In FIG. 2 is shown in section the exhaust control equipment 2 comprising a box-shaped casing 15 with a volume of 4 5 liters and a connecting pipe 11 connected to the manifold of the automobile engine and a connecting pipe 12 connected to the muffler. A pair of spaced-apart perforated metal plates or screens 14 are disposed in the casing 15 to define a space of one or two liters in which the catalysts are packed.
The catalysts generally comprise the very porous carriers consisting of the particles of alumina, silica or magnesia which are sintered at elevated temperatures and coated or mixed with platinum and the metal oxides such as copper, nickel, manganese, cobalt and iron oxides. However, recently it has been found out that the newly developed glass fiber catalysts are more effective to purify the exhaust gases. The carriers of these catalysts comprise the mesh fabrics of glass fibers or glass fiber fabrics (to be referred to as heat-resisting glass fiber fabrics hereinafter) of the type in which all of alkalines in glass fibers are eliminated by dipping these glass fibers in a strong acid bath whereby they may become rich with silica and may be rendered heat resistive with an increased activated surface area. To these carriers is applied platinum or the above described metal oxides. Therefore the problem is now how to provide an effective exhaust control equipment with the use of these mesh fabrics of glass fibers or heat-resisting glass fibers.
One arrangement of the priorart exhaust control equipment is illustrated in FIGS. 3a and 3b. Within a cylindrical casing 31 having a feed pipe 32 and a discharge pipe 33 is disposed a perforated pipe 34 with a perforated area being 20-50 percent of the total surface area. One end of the perforated pipe 34 is connected to the feed pipe 32 while the other end is closed by a plug or the like. The mesh-fabric type catalysts 35 of the type described above are wound around the perforated pipe 34 coaxially thereof. The weight of these catalysts is about 400-800 grams. The exhaust gases fed through the feed pipe 32 into the perforated pipe 34 are discharged through the perforations thereof, made into contact with the catalysts 35 and discharged into the discharge pipe 33.
The inventors made extensive studies and experiments in order to make full use of the catalysts in the reactions within the casing and also to prevent the temperature of the catalysts from being elevated by the heat dissipated from the exhaust gases, and succeeded in providing an excellent vehicle exhaust control equipment as will be described hereinafter with reference to FIGS. 4-7.
A first embodiment is shown in FIG. 4. Within a boxshaped casing 43 are disposed in parallel a plurality of small-sized chambers or units of the mesh-fabric type catalysts 47 of the type described, the adjacent catalyst units 47 being separated from each other by means of partition walls 44. These catalyst units 47 are sandwiched between a pair of perforated metal plates or wire screens 48 and 49. The axis of each of the rolled catalyst units 47 may be in parallel with the direction of the flow of the exhausted gases or the axis of the rolled catalyst unit 47 may be perpendicular to the direction of the exhaust gas flow so that the outer surface of the rolled catalyst unit 47 may be perpendicular to the axis of the passage 45. A number of the rolled catalyst units 47 is dependent upon the types of automotive engines, and is preferably 28.
A second embodiment of the present invention is shown in FIG. 5. A plurality of rolled catalysts units 58 similar to those 47 in the first embodiment described by reference to FIG. 4 are disposed in parallel on each side of an exhaust gas introduction passage 56 in communication with a feed pipe 51 of a box-shaped casing 53. The exhaust gases which have made contact with the catalysts 58 are discharged through the exhaust gas passages 57 into the discharge pipes-52 and 52 which are connected to a single pipe connectedto a muffler. As in the case of the first embodiment, the catalyst units 58 are sandwiched by a pair of perforated metal plates or wire screens 54 and 55 and are separated from each other by partition walls 59.
A third embodiment shown in FIG. 6 is similar to the second embodiment described above by reference to FIG. except that the cross sectional area of the central exhaust gas passage is gradually reduced from a feed pipe 61 toward the rear side of a box-shaped casing 63 on the side of its discharge pipes 62 and 62 which are also connected to a single pipe connected to a muffler. The catalyst units 67 are also sandwitched between the perforated metal plates or wire screens 64 and 65 and are separated from each other by the partition walls 68.
A fourth embodiment of the present invention will be described by reference to FIG. 5 because its longitudinal sectional view is substantially similar to that of the second embodiment. Whereas the second embodiment has the box-shaped casing, the fourth embodiment has a cylindrical casing 53 about 230 mm in diameter, and
4 the mesh fabric type catalysts 58 of the type described above are wound around a perforated pipe 54 within the casing 53 connected to the feed pipe 51. The exhausted gases are discharged into the discharge pipes 52 and 52' from the cylindrical casing 53.
A fifth embodiment of the present invention will be described by reference to FIG. 6 because its longitudinal sectional view is substantially similar to that of the third embodiment. Whereas the third embodiment has a box-shaped casing, the fifth embodiment has a cylindrical casing 63. The diameter of the passage is gradually reduced as in the case of the third embodiment. Each catalyst unit 67 and each partition wall are both in the form of a doughnut. In the third and fifth embodiments, the space of the catalyst unit is increased as it approaches toward the discharge end of the casing, but the purpose of the gradually reduced-diameter passage at the center of the casing is to prevent the exhaust gases deflected at the rear end of the passage from entering in large quantity into the last catalyst unit or units as compared with the exhaust gases which enter into the preceding units. Therefore the density of the catalysts in the last unit or units is preferably reduced. In the third embodiment where 12 catalyst units are disposed, the ratio of the weight of the catalysts in the first unit to that of the last unit is preferably 1.45:1 while in the fifth embodiment where six disk-shaped catalyst units are disposed, the ratio is preferably 1.35:].
In Table 1 below, the number of catalyst units and the weight of the catalysts in the first, second, third, fourth and fifth embodiments are shown.
Next a sixth embodiment of the present invention will be described by reference to FIGS. 70 and 7b. A cylindrical casing 73 has a feed pipe 71 and a discharge pipe 72, and mesh-fabric type catalysts 77 of the type described above are wound around a perforated pipe 78 in the casing 73 and are separated from each other by partition disks 70. It should be noted that the last partition disk 74 closes the perforated pipe 78 so that the exhausted gases will be prevented from directly passing into the discharge pipe 72 without passing through the catalyst units 77. Another perforated pipe 75' is disposed between the last partition disk 74 and the discharge pipe 72 so that the exhaust gases which passed through the catalyst units 77 may enter into the perforated pipe 75 before they are discharged into the discharge pipe 72. The weight of the catalysts in each unit is grams so that the total weight of the catalysts in four units is 480 grams. The exhaust gases introduced into the perforated pipe 78 through the feed pipe 71 are made to pass through the catalyst units 77 and then discharged into a muffler through the perforated pipe 75 and the discharge pipe 72.
In the above embodiments, an air pump or air blower has not been described which is driven by the automobile engine or the battery to feed the air into the exhaust control equipment in order to oxide CO, HC and the like in the exhaust gases which are not completely burnt in the engine, because such an air pump or blower is well known in the art and is required not only 2. By use of the partition walls or disks, the uniform temperature rise in the equipment may be attained. Furthermore, the temperature rise may be minimized. The reason is that the partition walls or disks are made in the vehicle exhaust gas control equipment of the 5 of metal and are placed adjacent to the heating catapresent invention but also in other prior art equiplysts so that the heat dissipation by the metal partition ments. Although not specifically stated in the specificawalls or disks may be much enhanced and the abnormal tion, it is clear to those skilled in the art to provide a temperature rise of the catalysts may be prevented. double-wall casing and place heat insulating materials Therefore the local thermal breakdowns of the catabetween the walls or to apply them on the outer surface 10 lysts may be effectively prevented. of the casing because the activity of the catalysts is gen- 3. The temperature'rise may be further reduced in case erally highly dependent upon a temperature and the deof the first, second and third embodiments because the sired temperature must be maintained within the cascasings are made in direct contact with the catalysts. ing. it is of course also obviousto those skilled in the 4. In the third and fifth embodiment, the exhaust gas art to provide, depending upon the characteristics of passage is gradually reduced in diameter from the feedthe catalysts used, heat dissipating means when the exing end toward the discharge end so that the volumes haust control equipment is used under some special e of the exhaust gases introduced into individual catalyst vironmental conditions or when the heat resistivity of units or chambers may be uniformly distributed. Therethe catalysts is low. fore the temperature rises in the catalyst units may be The following advantages ar accrued fr th pr made uniform and the local thermal breakdowns of the ent invention: catalysts may be effectively prevented. l. A plurality of small-sized catalyst units are disposed the f Y fifth and SiXth embodiment, h y in parallel so that the cleaning or purification effect e g are p y so that the fabrleatleh may may be much improved as compared with the prior art be mphfied at ess cost. exhaust eohtro] equipment In which the catalysts of the The advantages of the present invention will become e Welght are PhleecI ehe pesltloht Thls advahtage more apparent from the data given in Table 11 below. become e PP y e the Space e y The data were obtained by a gasoline-engine automoused for explahetleh: That In e of the Platlhum bile which were fitted with the vehicle exhaust control catalysts 10 grams Weight 'h e by t heatequipments of the first to sixth embodiments of the inl'eslshhg glass fibers the p e t y 15 times h vention during the travel of about 500 kilometers. The of the Catalysts 100 graths welghtused e Prior displacement of the engine was 1,500 cc. For the same art exhaust Centre] qt p Furthermore It was of comparison, the data of the vehicle exhaust control found out that the cleaning efficiency is much lowered equipment f the type. Shown in FIG 3 with 1,400 the Prior art exhaust Control q fp Where h grams of the mesh-fabric type heat-resisting-glass-fiberchtalysts more 500 gf Wetght are P carrier catalysts are shown also in Table II. The cataone space as compared with the exhaust control equ1plysts used are as f ll mentof the presentmventlon in wh ch these catalystS Carriers: mesh-fabrics of heat-resisting glass fibers are l "h uhlts each cohtammg 60400 grams Catalysts: metal oxides whose major portions are coahd dlsposed patahet other words, y the Pttmhel 4O balt oxides and copper oxides and which contain as arrangement of the small-sized catalyst units, the clea auxiliary catalysts small quantities of chromium oxing or purification effect may be much improved while ides, aluminum oxides, magnesium Oxides and the exhaust control equipment may be made compact phosphorus in size.
Table ll idhl g after 500 km travel I average CO average weight of purifi- CO in '71 CO in 7: temperature catalysts cation at at of catalysts in grams rate in 7:- inlct outlet in "C comparison (See Fro. 31
1,400 68 1.2 0.6 680 first embo- 720 92 1.4 0.3 540 diment second embo- 600 94 1.5 0.2 570 diment third embos00 94 1,7 0.3 490 diment fourth embo- 540 93 0.x 0.15 610 dimcnt fifth embo- 540 1.0 0.2 630 diment sixth embodiment In all of the embodiments described above, the numbers of small-sized catalyst units or chambers as well as the weights and types of the catalysts used are specified, but it is understood that the arrangements of more than two small-sized catalyst units or chambers in parallel are within the scope of the present invention. It is also understood that the types and weights of the catalysts are of course selected depending upon the types of the automobiles and that the catalysts may be of the type in which platinum or metal oxides are applied as the catalyst layers upon the surfaces of the fabrics woven from the heat-resisting glass fibers. It is also understood that the gradual reduction in diameter of the perforated pipe 78 in the sixth embodiment is also within the scope of the present invention.
The vehicle exhaust control equipment in accordance with the present invention may be fabricated at less cost and has an excellent exhaust gas cleaning or purification effect, and is very effective as an anti-atmospheric-pollution control equipment.
What is claimed is:
l. A vehicle exhaust control device capable of dissipating the heat produced during catalytic oxidation of exhaust gases without thermal breakdown comprising in combination an outer casing having gaseous feed means and discharge means,
an exhaust gas introduction passage within the interior of said casing in communication with said gaseous feed means comprising a central perforated pipe,
a plurality of heat conducting annular partitions having a diameter less than the diameter of said outer casing positioned around said perforated pipe which are not permeable to the gas and which divide portions of the interior of said outer casing into a plurality of small catalyst chambers which are arranged parallel to the flow of exhaust gas through said exhaust gas introduction passage and forming a continuous gas annular passage between said catalyst chambers and said outer casing,
woven meshlike catalysts positioned within said small catalyst chambers and wound around said perforated pipe to form separate catalyst elements contiguous with said heat conducting partitions, whereby said catalyst elements are maintained in said chamber free of perforated retaining members, and
at least one of said partitions blocking the downstream end of said exhaust gas introduction passage to cause the exhaust gas to pass through said small catalyst chambers containing said woven meshlike catalysts and into said continuous gas annular passage,
whereby the heat produced in the catalytic oxidation is effectively dissipated to prevent thermal breakdown of the catalyst.