Title of Invention	EXHAUST GAS PURIFICATION DEVICE
Abstract	In an exhaust gas purification device comprising a tubular catalytic body produced by applying catalyst on the tubular carrier installed in an exhaust gas passage for purifying gas, to enable manufacturing of a tubular carrier of small diameter at low manufacturing cost and at ahigh degree of dimensional accuracy, and further to improve purifying capability of the exhaust gas purification device with new ingenuity in configurations. The tubular carrier obtained bycutting a steel pipe member formed by extrusion or the like into a prescribed length and formed with a number of inwardly projected deformities is used

Title of Invention

EXHAUST GAS PURIFICATION DEVICE

Abstract

In an exhaust gas purification device comprising a tubular catalytic body produced by applying catalyst on the tubular carrier installed in an exhaust gas passage for purifying gas, to enable manufacturing of a tubular carrier of small diameter at low manufacturing cost and at ahigh degree of dimensional accuracy, and further to improve purifying capability of the exhaust gas purification device with new ingenuity in configurations. The tubular carrier obtained bycutting a steel pipe member formed by extrusion or the like into a prescribed length and formed with a number of inwardly projected deformities is used

Full Text	FORM 2 THE PATENTS ACT 1970 [39 OF 1970] COMPLETE SPECIFICATION [See Section 10] "EXHAUST GAS PURIFICATION DEVICE" HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan The following specification particularly describes the nature of the invention and the manner in which it is to be performed :- The present invention relates to exhaust gas purification device. 2- i The present invention relates to an exhaust gas purification device for a small internal combustion engine used for motorcycles or the like. In this specification, the term "tube material" represents material for producing a carrier by deformation process, the term "tubular carrier" represents a target object for applying catalyst formed by deforming or punching the tube material, and the term "tubular catalytic body" represents the tubular carrier with catalyst applied thereon. [0002] [Description of the Related Art] The exhaust gas purification device for a small internal combustion engine used for motorcycles or the like is a device comprising a structure obtained by applying and holding catalyst on a carrier, so called catalytic body installed in a flow of exhaust gas for purifying harmful components contained in exhaust gas. The configuration of the carrier generally used is the tubular carrier 01 formed with punched holes 02 as shown in Fig. 26 and applied with catalyst, which is disposed in parallel with the flow G of exhaust gas (Japanese Laid-Open No. 30432/1998). [0003] In the related art, as shown in Fig. 27, such tubuiar carrier 01 with punched holes is formed by rolling out the rolled metal plate material 03 into a flat plate, performing punched hole process 04, cutting into a prescribed size 05, performing bending process such as U-bend process 06, O-bend process 07 or the like, bringing both edges into contact, and welding 08 them. [0004] 3 [Problems to be Solved by the Invention] In the process of manufacturing the tubular carrier 01 in the related art as shown in Fig. 27, many numbers of processes are needed, and thus the manufacturing cost is disadvantageously increased. When using it for motorcycles of small air volume displacement, for example, of four-stroke, 125 cc or less displacement, it is difficult to decrease the diameter for mounting it into the narrow exhaust system, especially when manufacturing the tubular carrier of less than 20 mm in diameter in the method of related art, a problem that the accuracy in dimension is lowered may arise. [0005] When the tubular catalytic body 09 with punched holes manufactured by applying catalyst on the inner and outer surfaces of the tubular carrier 01 with punched holes in the related art is placed in a flow of exhaust gas, there arise a problem that the catalyst body must be upsized in order to secure sufficient contact between exhaust gas G and catalyst because turbulence of gas flow rarely occurs as shown in Fig. 28 since the surface of the tube is smooth. [0006] The present invention is intended to enable manufacturing of a tubular carrier of small diameter as described above at low manufacturing cost and high degree of accuracy, and to improve purifying capability of the exhaust 4 gas purification device with new ingenuity in configurations. [0007] [Means for Solving the Problems and Effects] The present invention is intended to solve the aforementioned problems, and the invention as set forth in Claim 1 is an exhaust gas purification device comprising a tubular catalytic body produced by applying catalyst on the tubular carrier installed in an exhaust gas passage for purifying gas, characterized in that the tubular carrier is a tube material obtained by cutting a steel pipe member formed by extrusion or the like into a prescribed length and formed with a number of inwardly projected deformities. [0008] With the present invention constructed as described above, since the tube material may be a tube which is commercially available as a pre-molded tube, and the inwardly projected deformities can be formed easily from the outside of the tube, the number of manufacturing process may be reduced and thus the manufacturing cost may also be reduced. When the commercially available tube material is used, the tube having diameter less than 20 mm may also be produced with a high degree of accuracy. In addition, since optimization of the configuration of the projected deformities may generate turbulence in exhaust gas flowing inside the tubular catalytic body, downsizing of the catalytic body and improvement of 5 exhaust gas purification rate may be realized. [0009] The invention as set forth in Claim 2 is an exhaust gas purification device according to Claim 1, characterized in that the tubular carrier is positioned inside the resonance tube and formed with communication holes adjacent to the rear end of the respective inwardly projected deformities to bring the inside and outside of the tube into communication with each other. [0010] With the present invention constructed as described above, optimization of the configuration of the projected deformities with communication holes may generate turbulence in exhaust gas flowing inside the catalytic body, and reduction of the amount of gas leaking outside may reduce effects on exhaust pulsation, whereby performance of the internal combustion engine as well as purifying rate of exhaust gas may be improved. [0011] The invention as set forth in Claim 3 is an exhaust gas purification device according to Claim 1 and Claim 2, characterized in that the inwardly projected deformity forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity increases gradually from zero from the 6 upstream end toward the downstream side. With the present invention in this arrangement, increase in resistance with respect to gas flow may be alleviated. [0012] The invention as set forth in Claim 4 is an exhaust gas purification device according to Claim 1 and Claim 2, characterized in that the inwardly projected deformity forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity increases gradually from zero from the upstream end toward the downstream side and that the portion of the space having a largest cross sectional area is at the rear end of the inwardly projected deformity. Since such arrangement of the present invention causes turbulence in exhaust gas rearward of the projected deformity and thus purifying rate of exhaust gas may be improved. [0013] The invention as set forth in Claim 5 is an exhaust gas purifying apparatus according to Claim 1 and Claim 2, characterized in that the inwardly projected deformity forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity increases gradually from zero from the upstream end toward the downstream side and decreases relatively suddenly from the portion having the largest cross 7 sectional area toward the downstream side until it reaches zero. This means may also serve to improve purifying rate of exhaust gas since the present invention gives turbulence to exhaust gas rearward of the projected deformity. [0014] The invention as set forth in Claim 6 is an exhaust gas purification device according to Claim 4 and Claim 5, characterized in that the angle formed between the ridgeline of the inwardly projected deformity and the original wall surface of the tube of the inwardly projected deformity forms an acute angle. This means may also serve to improve purifying rate of exhaust gas since the present invention gives turbulence to exhaust gas rearward of the projected deformity. [0015] The invention as set forth in Claim 7 is an exhaust gas purification device according to Claim 4 to Claim 5, characterized in that the height of the inwardly projected deformity is within the range of (17±5)% of the inner diameter of the tubular member. With the present invention in this arrangement, production efficiency may be improved by extremely superior processability and manuf acturability while maintaining the purifying rate of toxic gas in the constant level without specifically increasing resistance in the flow path of exhaust gas in comparison with the tubular catalytic body with punched holes in the related art. 8 [0016] The invention as set forth Claim 8 is an exhaust gas purification device according to Claim 4 and Claim 5, characterized in that the inwardly projected deformities are formed in row at regular intervals in the axial direction of the tube of the tubular carrier, and the distance between the inwardly projected deformities adjacent in the aforementioned axial direction of the tube is 20mm to 30 mm, and a plurality of rows of the aforementioned rows are formed on a single tubular carrier. With the present invention in this arrangement, such disadvantages that the effect is lowered because the distances are too short and thus the rear inwardly projected deformities are hidden in the backlash of the inwardly projected deformities on the front portion, or that the effect is lowered because the distances are too long and thus total number of internal projecting deformities is insufficient and thus optimal intervals can be provided. [0017] The invention as set forth in Claim 9 is an exhaust gas purification device according to Claim 1 to Claim 8, characterized in that the tubular catalytic body is applied with catalyst only on the inner surface of the tubular carrier. The present invention utilizes that the purification effect of the inner side of the tube is significantly higher than that in the outside by the presence of the projected deformities 9 on the inner surface of the tube, and intends to reduce the cost of catalyst by applying it only on the inner surface of the tubular carrier and allowing exhaust gas to flow into the tube, thereby improving the purification effect with respect to the costs of catalyst. [0018] The invention as set forth in Claim 10 is an exhaust gas purification device according to Claim a to Claim 9, characterized in that the tubular catalytic body of the exhaust gas purification device is installed in the passage of the exhaust gas in the muffler of the motorcycle for purifying gas. With the present invention in this arrangement, purification of exhaust gas can be performed without adding a separate device. [Brief Description of the Drawings] [Fig. 1] Fig. 1 is a drawing showing a first embodiment of tubular carrier 1 according to the exhaust gas purification device of the present invention, in which (a) is a drawing of a tubular carrier 1 when viewed from obliquely behind, and (b) is a drawing of the same when viewed from the back. [Fig. 2] Fig. 2 shows three view of the same tubular carrier 1, in which (a) is a side view, (b) is a cross sectional view taken along the line B-B of the figure (a), and (c) is a cross sectional view taken along the line C-C of the figure (b)., [Fig. 3] 10 Fig. 3 is a drawing showing the process of manufacturing the tubular carrier. [Fig. 4] Fig. 4 is a perspective view showing an inwardly projected deformity 2 and a deformity forming tool 7 for forming the same inwardly projected deformity of the tubular carrier 1 of the first embodiment, in which (a) is a view of one of inwardly projected deformities 2 when viewed from inside the tube, and (b) is a outline view of the deformity forming tool 7 to be used for deforming the inwardly projected deformity 2. [Fig. 5] Fig. 5 is a drawing of streamlines in a state in which the tubular catalytic body 11 with inwardly projected deformity manufactured by applying catalyst on the tubular carrier is placed in the flow of exhaust gas. [Fig. 6] Fig. 6 is a side view of the muffler 12 of an internal combustion engine of four-stroke, 125 cc for motorcycles to which the aforementioned catalytic body 11 is mounted. [Fig. 7] Fig. 7 is a lateral cross section of the muffler. [Fig. 8] Fig. 8 is a vertical cross section of the muffler taken along the vertical plane. 11 [Fig. 9] Fig. 9 is a horizontal cross section of the same muffler. [Fig. 10] Fig. 10 is a drawing showing a tubular carrier according to the second embodiment of the exhaust gas purification device according to the present invention in which (a) is a rear perspective view of the tubular carrier, and (b) is a back view. [Fig. 11] Fig. 11 is a drawing showing a tubular carrier according to the third embodiment of the exhaust gas purification device according to the present invention, in which (a) is a rear perspective view of the tubular carrier, and (b) is a back view. [Fig. 12] Fig. 12 is a drawing showing a tubular carrier according to the fourth embodiment of the exhaust gas purification device of the present invention, in which (a) is a rear perspective view of the tubular carrier, and (b) is a back view. [Fig. 13] Fig. 13 shows three surfaces of the tubular carrier according to the fifth embodiment of the exhaust gas purification device of the present invention, in which (a) is a side view, (b) is a cross sectional view taken along the line B-B in the figure (a), and (c) is a crose sectional view taken along the line C-C in the figure (b). [Fig. 14] 12 Fig. 14 is a perspective view showing the configuration of the inwardly projected deformity 46 and the deformity forming tool 47 for processing the inwardly projected deformity of the tubular carrier 45 of the fifth embodiment, in which (a) is a drawing of a single inwardly projected deformity 46 viewed from inside the tube, and (b) is a outline view of the deformity forming tool 47 used for deforming the inwardly projected deformity 46. [Fig. 15] Fig. 15 is a perspective outline view of the tubular carrier according to the fifth embodiment provided with a variety of numbers of rows of inwardly projected deformities. [Fig. 16] Fig. 16 is a drawing of streamlines in a state in which exhaust gas flow G is introduced into the interior of the tubular catalytic body 48 formed by applying catalyst on the inner surface of the tube of the tubular carrier 45 with inwardly projected deformities 46 without hole in the fifth embodiment. [Fig. 17] Fig. 17 is a drawing showing definitions of the inner diameter of the tubular carrier in the fifth embodiment and of the height of the inwardly projected deformities. [Fig. 18] Fig. 18 shows a result of an experiment on the gas 13 purification rates (%) of the tubular catalytic body 48 that are formed by providing inwardly projected deformities of 1 mm, 4mm, and 7mm in height on the tubular members of 23.4 mm in inner diameter. The gas purification rate (%) of the tubular catalytic body 09 having punched holes of the identical inner diameter is also shown. [Fig. 19] Fig. 19 shows a result of an experiment on the resistance in the flow path (Pa) in the tubular catalytic body 48 under the same conditions as Fig. 18. The resistance of the flow path (Pa) of the tubular catalytic body 09 with punched holes of the identical inner diameter is also shown. [Fig. 20] Fig. 20 shows these results of the experiments altogether, showing the height (mm) of the preferable inwardly projected deformity with respect to the inner diameter of the tubular member (mm), and the range of tolerance thereof. [Fig. 21] Fig. 21 is a side view of a motorcycle 50 provided with the tubular catalytic body of the fifth embodiment. [Fig. 22] Fig. 22 is a side view of the exhaust pipe 64 and the muffler 65. [Fig. 23] Fig. 23 is a plan view. 14 [0019] [Detailed Description of Preferred Embodiments] Fig. 1 is shows an embodiment of the tubular carrier for an exhaust gas purification device according to the present invention, in which (a) is a drawing of a tubular carrier 1 when viewed from.obliquely behind, and (b) is a drawing of the same when viewed from the right back. The tubular member is formed on its periphery with a number of inwardly projected deformities 2 formed by deforming the tubular member itself inwardly so as to project therefrom. One side of each projected deformity is shared and punched to form a 15 communication hole 3, through which the outside and the inside of the tube is communicated. The arrow G represents the direction of the flow of exhaust gas. [0020] Fig. 2 shows three view of the same tubular carrier, in which (a) is an outline view when viewed from the side, (b) is a cross sectional view taken along the line B-B of the figure (a), and (c) is a cross sectional view (viewed toward the front) taken along the line C-C of the figure (b). When viewed from the outside of the tube, the configuration of the inwardly projected deformity 2 is a triangular recess, and when viewed from the back toward the front, a triangular communication hole 3 formed on one side of each inwardly projected deformity by sharing and punching the tubular member can be seen. When using this carrier, it is arranged so that exhaust gas flows from the left to the right, and thus the inwardly projected deformity 2 is formed at a slant such that the triangular communication hole 3 described above opens toward the rear. The angle of inclination 9 is preferably about 30 degrees. [0021] Fig. 3 is a drawing showing the process of manufacturing the same tubular carrier. A stainless pipe member 4 precut into a required length, which is commercially available, is used as material for manufacturing the carrier of this embodiment. A relief-grooved core metal 5 formed with rows 16 of a plurality of recessed grooves corresponding to the rows of inwardly projected deformities which will be formed along the generating line of the tubular member, so called relief grooves 5a, is inserted into the precut tubular member 4 described above, and in this state, is inserted into the metallic holding block 6 formed with an elongated cavity 6a having circular cross section at the center thereof and an elongated opening 6b formed on top thereof. Subsequently, the deformity forming tool 7 is abutted against the outer peripheral surface of the tubular member 4 at the positions corresponding to the relief grooves 5a described above and knocked therein from the opening 6b on top. When formation of a row of inwardly projected deformities 8 is finished, the deformity forming tool 7 is withdrawn upward, the tubular member 4 and the core metal 5 are rotated 9 together for the formation of inwardly projected deformities of the next row 10. By repeating these procedures and forming inwardly projected deformities 2 along the entire circumference of the tubular member 4, a tubular carrier 1 is completed. When the catalyst is applied on it, a tubular catalytic body is completed. [0022] Fig. 4 is a perspective view showing an inwardly projected deformity 2 and a deformity forming tool 7 for processing the same inwardly projected deformity, in which (a) 17 is a view of one of inwardly projected deformities 2 when viewed from inside the tube, and (b) is a outline view of the deformity forming tool 7 to be used for processing the inwardly projected deformity 2. The angle 0 between the ridgeline 2a of the inwardly projected deformity 2 and the original wall surface of the tube forms an acute angle, and preferably about 30 degrees. In order to shear the rear edge 2b of the deformity 2, the edge of the rear edge sharing portion 7a of the deformity forming tool 7 is formed with a sharp blade. [0023] Pig. 5 is a drawing of streamlines in a state in which the tubular catalytic body 11 with inwardly projected deformity 2 manufactured by applying catalyst on the tubular carrier 1 of the embodiment described above is placed in the flow of exhaust gas G. In the tubular catalytic body 11 with inwardly projected deformity, since a heavy turbulence occurs on the inner surface of the tube at the rear end of the inwardly projected deformity, and exhaust gas, being swirling, is brought into heavy contact with the catalyst applied on the carrier, the effect of exhaust gas purification is significantly higher than the case of the tubular catalytic body 09 with punched holes in the related art in which the laminar flow of gas flows along the surface (See Fig. 28). [0024] Subsequently, an embodiment in which the aforementioned 18 tubular catalytic body 11 with inwardly projected deformity is applied to the exhaust system of the motorcycle will be described. Fig. 6 is a side view of the muffler 12 of an internal combustion engine of four-stroke, 125 cc for motorcycles to which the aforementioned catalytic body 11 is mounted, and Fig. 7 is a lateral cross section of the same muffler (cross section taken along the line VII-VII in Fig. 6 and viewed from the rear). As shown in Fig. 7, four conduits A, B, C, and D are provided within the muffler 12. Fig. 8 is a vertical cross section of the muffler taken along the vertical plane (cross section taken along the line VIII-VIII in Fig. 7). Fig. 9 is a horizontal cross section (taken along the line IX-IX in Fig. 7) [0025] In Fig. 8 and Fig. 9, the central portion of the body of the muffler 12 has a dual body comprising outer body plate 13 and the inner body plate 14, which are held with each other by the partition plate 15 with gap filled with glass wool 16. The front portion of the body is covered by the semi-spherical front cap 17, into which an exhaust pipe 18 which continues into the internal combustion engine is inserted. The rear portion of the body is covered by the rear cap outer plate 19 and the rear cap inner plate 20, which are filled with glass wool 21 therebetween. A rear end annular portion 22 is provided on the rear surface of the rear cap. Inside of the 19 inner body plate 14, there are provided a first diaphragm 23 and a second diaphragm 24 in order from the front, which divide the interior of the muffler 12 into three compartments. These compartments are referred to as the first compartment 25, the second compartment 26, and the third compartment 27 in order from the front for the purpose of explanation below. In the muffler, there are provided four conduits A, B, C, and D being different in length for communicating the respective compartments 25, 26, 27 in different combinations. [0026] The conduit A located at the upper portion in the muffler comprises, as shown in Fig. 8, an inlet tube 28 continuing to the exhaust pipe 18 located outside, a connecting pipe 29 continuing to the inlet pipe 28, a diffuser pipe serving as a catalytic body 30 continuing to the connecting pipe 29, and a resonance pipe 31 covering the outside of the diffuser pipe serving as a catalytic body 30. The conduit A passes through the first diaphragm 23 and the second diaphragm 24, and exhaust gas discharged from the internal combustion engine passes through the conduit A and injected firstly into the third compartment 27. [0027] In Fig. 9, the conduit B on the right side in the muffler comprises a communication pipe 32. The conduit B passes through the second diaphragm 24, and exhaust gas previously 20 injected into the third compartment 27 passes through the conduit B and enters into the second compartment 26. [0028] In Fig. 9, the conduit C on the left side of the muffler comprises a communication pipe 33. The conduit C passes through the first diaphragm 23, and exhaust gas previously entered into the second compartment 26 passes through the same conduit C and enters into the first compartment 25. [0029] In Fig. 8, the conduit D located at the lower portion in the muffler comprises a front diffuser assembly 34 and the rear diffuser assembly 35, which are connected by the guide pipe 36 with each other. The conduit D passes through the first diaphragm 23 and the second diaphragm 24, and then through the rear cap outer plate 19 and the rear cap inner plate 20 at the rear end portion of the rear diffuser assembly 35, and is projected to the outside. Exhaust gas previously entered into the first compartment 25 is discharged to the outside through the conduit D. The muffler 12 is a device for lowering the exhaust sound by means of capability of discharging exhaust gas of the internal combustion engine through the complex passages as described above, and of the action as diffusers 30, 34, 35. [0030] The diffuser pipe serving as a catalytic body 30, being 21 one of the applications of the aforementioned tubular catalytic body 11, is a tubular catalytic body 11 having inwardly projected deformities obtained by applying catalyst on the tubular carrier 1 provided with the inwardly projected deformities as shown in Fig. 1 placed at the end of the conduit A continuing directly to the exhaust pipe 18 in the muffler 12 where a dif fuser pipe provided with a number of punched hole was situated in the related art instead of the same diffuser pipe. The diffuser pipe of the related art is adapted to damp the pressure energy when exhaust gas is flown through a number of punched holes, and generates sound deadening effects with interaction with the resonance pipe located outside, thereby lowering the sound volume. Since the tubular catalytic body 11 of this embodiment is provided with a number of communication holes 3 on the periphery thereof, it can function as a diffuser pipe serving as a catalytic body 30 having a sound deadening capability instead of the diffuser pipe with punched holes in the related art. [0031] In the diffuser pipe serving as a catalytic body 30 of this embodiment, exhaust gas is introduced from the connecting pipe 29 so that gas flows inside the tube. The main flow of gas flows within the pipe, and a small quantity of gas flows outside the tube. Therefore, even when the tube applied with the catalyst only on the inner side thereof is used, the effects 22 that bear comparison with the tube applied with the catalyst on the outer and inner sides thereof can be produced. In this arrangement, the cost required for manufacturing catalysts can be reduced by half, and thus a large effect in terms of cost can be obtained. [0032] Fig. 10 is a drawing showing a tubular carrier 37 according to the second embodiment of the exhaust gas purification device according to the present invention. The inwardly projected deformity 38 of this embodiment has a round portion at the front and communication hole 39 linearly shared and punched at the rear end. The effects of this embodiment are almost the same as the tubular carrier of the first embodiment. [0033] Fig. 11 is a drawing showing a tubular carrier 40 according to the third embodiment of an exhaust gas purification device according to the present invention. The inwardly projected deformity 41 of this embodiment has a shape formed by forming a shared and punched hole 42 elongated in the direction of the axis of the tube and bending the tubular member material inwardly of the tube about the side which is not punched. Gas is communicated between the outside and the inside of the tube through shared and punched holes 42 elongated in the direction of axis of the tube. in the tubular carrier 23 according to this embodiment, the catalyst is applied both on the inner and outer sides of the tube so as to allow gas to come into contact with both surfaces effectively. [0034] Fig. 12 is a drawing showing a tubular carrier 43 according to the fourth embodiment of the exhaust gas purification device of the present invention. The inwardly projected deformity 44 of this embodiment is round as a part of a spherical surface, and there is no hole for communicating the inside and the outside of the tube. The tubular carrier of this embodiment can be applied to the exhaust gas purification device of the type in which exhaust gas is flown only along the inner surface of the tube. [0035] Fig. 13 shows three surfaces of the tubular carrier 45 according to the fifth embodiment of the exhaust gas purification device according to the present invention, in which (a) is an outline view shown from the side, (b) is a cross sectional view taken along the line B-B in the figure (a), and (c) is a cross sectional view taken along the line C-C in the figure (b) (when viewed toward the front). The configuration of the inwardly projected deformity 46 is a rounded trapezoidal recess when viewed from the outside the tube, and no hole that communicates the inside and the outside of the tube is provided. When viewed from the rear toward the front, the inwardly 24 deformed deformity 46 formed by deformation of the tubular member can be seen. When using this carrier, it is disposed so that exhaust gas flows in the tube as shown in the direction of the arrow G. [0036] Fig. 14 is a perspective view showing the configuration of the inwardly projected deformity 46 of the tubular carrier 45 according to Claim 5 and the deformity forming tool 47 for processing the inwardly projected deformity 46, in which (a) is a drawing of a single inwardly projected deformity 46 viewed from inside of the tube, and (b) is a outline view of the deformity forming tool 47 used for deforming the inwardly projected deformity 46. [0037] The inwardly projected deformity 46 of this embodiment is, as shown in Fig. 14(a), pyramid shape elongated in the direction of gas flow G with inequilateral bottom surface, and inclination of the ridgeline located on the front side of the apex when viewed in the direction of gas flow with respect to the tube wall out of ridgelines extending in the fore-and-aft direction is more gentle in comparison with inclination of the ridgelines on the backside of the apex with respect to the tube wall. The angle of the ridgeline on the front side of the apex with respect to the tube wall designated by 9 is an acute angle, which is preferably in the order of 30 degrees. 25 The portion near the apex is the portion of the largest cross sectional area, and the lateral cross sectional area decreases relatively suddenly from the portion of the largest cross sectional area toward the downstream to zero. Though the apex, ridgelines, and the like are shown in sharp lines in the figure, they are formed into the rounded shape in practice. [0038] Fig. 14(b) is an perspective outline view of the deformity forming tool 47 for machining the inwardly projected deformity 46. In the deformity forming tool in practical use, the apex and the edges along the ridgelines are rounded so as to prevent the tubular member from being scratched. Inclination of the front ridgeline with respect to the tube wall is preferably in the order of 30 degrees as described above. The process of manufacturing the tubular carrier 45 using the deformity forming tool 47 is the same as the process of manufacturing the tubular carrier 1 shown in Fig. 3. [0039] Fig. 15 is a perspective outline view of the tubular carrier according to the fifth embodiment provided with a variety of numbers of rows of inwardly projected deformities. This embodiment may be formed by forming two to six, or some other plural number of rows of the inwardly projected deformities in the axial direction of the tubular carrier at regular intervals. Forming an even number of rows, 26 positioning the opposed rows at the symmetrical positions with respect to the centerline of the tube, and machining the inwardly projected deformities on the opposed rows simultaneously from above and below for example with a suitable tool may improve the manufacturing efficiency of the tubular carrier. [0040] Fig. 16 is a drawing of streamlines in a state in which exhaust gas flow G is introduced in the tubular catalytic body 48 formed by applying catalyst on the inner surface of the tube of the tubular carrier 45 with inwardly projected deformities 46 without hole in this embodiment. In the example shown in the figure, the tubular catalytic body 48 is held in a cantilevered manner, and exhaust gas is not flowing outside the tube. In this tubular catalytic body 48, since the lateral cross sectional area decreases relatively suddenly from the portion of largest lateral cross sectional area of the inwardly projected deformity 46 toward the downstream side, and finally the lateral cross sectional area of the projected portion becomes zero, a heavy turbulence occurs on the inner surface of the tube and at the rear end of the inwardly projected deformity. Since exhaust gas is heavily brought into contact with catalyst applied on the inner surface of the carrier by this turbulent phenomenon, the effect of exhaust gas purification is significantly high with respect to the tubular 27 catalytic body 09 with punched holes in the related art in which gas flow flows on the surface laminarly (Fig. 28). [0041] The tubular catalytic body 11 having inwardly projected deformities 2 with holes shown in Fig. 5 is used in such a manner that the tube is applied with catalyst on the inner side and the outer side and exhaust gas is allowed to flow inside and outside the tube through the holes. Since the same amount of catalyst is applied on the outer surface as well as on the inner surface regardless of the fact that the amount of gas flown on the outer surface of the tube is smaller with respect to that flown on the inner surface of the tube, the amount of catalyst to be used on the outer surface is almost the same amount as that to be used on the inner surface so that a high effect cannot be expected in terms of the effect with respect to the cost. The tubular catalytic body 48 having inwardly projected deformities 46 without holes according to the fifth embodiment shown in Fig. 16 is improvement thereof, in which catalyst is applied only on the inner surface of the tube and exhaust gas is allowed to flow only through the inside of the tube. Securing the contact surface between exhaust gas and catalyst may be adjusted by slightly increasing the length of the tube, and so on. [0042] The higher the internal projected deformity is, the more 28 the rate of purifying harmful substances increases. However, since the inwardly projected deformities block the flow path of gas simultaneously, the resistance in the flow path increases, and thus lowering of the output of the internal combustion engine occurs. In order to put the present invention into practical use, it is required to realize the purification rate and resistance in the flow path at least in the same level as the tubular catalytic body 09 having punched holes in the related art (Fig. 28) . Therefore, an experiment for obtaining the optimal interrelation between the internal diameter of the tubular member and the height of the inwardly projected deformity was conducted. A part of it will be described below. [0043] Fig. 17 is a drawing showing definitions of the inner diameter of the tubular member of the material of the tubular carrier 45 in the fifth embodiment and of the height of the inwardly projected deformities after machining. Fig. 18 shows a curve connecting plotted points representing the gas purification rates (%) of the tubular catalytic body 48 that are formed by providing inwardly projected deformities of 1 mm, 4mm, and 7mm in height on the tubular members of 23.4 mm in inner diameter, and Fig. 19 shows a curve connecting plotted points representing the resistance in the flow path (Pa) in the tubular catalytic body 48 under the same conditions. In 29 these figures, the gas purification rate (%) and the resistance of the flow path (Pa) of the tubular catalytic body 09 with punched holes having the same inner diameter as the aforementioned tubular catalytic body 48 are shown in the respective figures for the sake of comparison. Since the tubular catalytic body 09 with punched holes is nothing to do with the height of the inwardly projected deformities, it is shown as a constant value. [0044] From these figures, when the tubular member of 23.4 mm in inner diameter was used, the tubular catalytic body 48 having inwardly projected deformities being 4 mm in height is as almost equal to the tubular catalytic body 09 with punched holes of identical inner diameter in terms of performance regarding exhaust gas purification rate (%) and resistance in the flow path (Pa), and when the height of the inwardly projected deformity exceeded 4 mm, the resistance in the flow path (Pa) suddenly increases regardless of the fact that the exhaust gas purification rate (%) did not increase that much, while the height of the inwardly projected deformity was lower than 4 mm, the exhaust gas purification rate (%) suddenly decreased, but the resistance in the flow path (Pa) did not decrease much as a consequent. From these results of the experiment, the results was such that the preferably height of the inwardly projected deformity was in the range of (17±5)% of the inner 30 diameter of the tubular member, considering the tolerable range. The range of the height of the inwardly projected deformity when the tubular member of 23.4 mm in inner diameter is used is the range approximately between 2.8 mm and 5.2 mm. [0045] As a result of the same experiment conducted also on the tubular catalytic bodies having some other diameters, it was found that the preferable height of the inwardly projected deformity was (17±5)% of the inner diameter of the tubular member even when the tubular members are different in inner diameter. Fig. 20 shows these results of the experiments altogether, in which the horizontal axis represents the inner diameter of the tubular member (mm) and the vertical axis represents the height of the inwardly projected deformity (mm). The optimal height of the inwardly projected deformity is represented by a thick solid line, and the limit of the tolerable range is represented by a thin solid line. With the present embodiment in this arrangement, production efficiency may be improved by extremely superior processability and manufacturability while maintaining the purifying rate of toxic gas in the constant level without specifically increasing resistance in the flow path of exhaust gas in comparison with the tubular catalytic body with punched holes in the related art. [0046] 31 In the tubular catalytic body of the present embodiment, it was found that the inwardly projected deformities were formed in row in the axial direction of the tube, and the distance L (See Fig. 15) between the inwardly projected deformities 46 adjacent in the axial direction of the tube was preferably between 20 and 30 mm. When the intervals are too short, the effect is lowered because the rear inwardly projected deformities are hidden in the backlash of the inwardly projected deformities on the front portion. While when the intervals are too long, the effect is lowered due to insufficient number of internal projecting deformities. By employing the aforementioned intervals, such drawback may be prevented. [0047] The above described experiment was conducted also on the inwardly projected deformities with holes as shown in Fig. 2 and so on, and it was verified that the results of the aforementioned experiment that the height of the inwardly projected deformity was preferably within the range of (17±5) % of the inner diameter of the tubular member, and that the dimension of the distance between the inwardly projected deformities adjacent in the axial direction of the tube is preferably between 20 and 30 mm can be applied to the inwardly projected deformities of some other configurations. [0048] 32 Fig. 21 is a side view of a motorcycle 50 provided with the tubular catalytic body of the present embodiment. A head pipe 52 is provided at the front end of the vehicle body frame 51, on which a handle 53 and a front fork 54 are rotatably held, and a front wheel 55 is rotatably supported by the front fork 54. The upper end of a shock absorbing device 56 is mounted at the rear portion of the vehicle body frame 51, a power unit 57 is suspended between the center portion of the vehicle body frame 51 and the lower end of the shock absorbing device 56, and a rear wheel 58 is rotatably mounted on the rear portion of the power unit 57. The carburetor 62 and the air cleaner 63 are connected to the cylinder head 60 of the internal combustion engine 59 constituting the front portion of the power unit 57 via an air intake pipe 61, and a muffler 65 is connected to the same cylinder head 60 via an exhaust pipe 64. In the figure, the exhaust pipe 64 and the muffler 65 are disposed on the far side of the vehicle body, and thus they are shown by broken hatching so as to demonstrate the position clearly. The vehicle body frame 51, the internal combustion engine 59, and the like are covered by the front cover 66, the body cover 67, and the like. A seat 68 is provided on the upper portion of the body cover 67. A spare tire 69 is provided on the rear portion of the body cover 67. [0049] Fig. 22 is a side view of the exhaust pipe 64 and the 33 muffler 65, and Fig. 23 is a plan view thereof. The front end of the exhaust pipe 65 is provided with a flange portion 70 for connecting it to the cylinder head 60, and the muffler 65 is provided with two brackets 71, 72 for mounting it to the structural portion of the power unit 57. A heat shield plate 73 is provided on the side surface of the muffler. [0050] Fig. 24 is a side view showing the interior of the muffler 65, and Fig. 25 is a plan view showing the interior of the same muffler. The muffler 65 is covered by a case 74, and the interior thereof is divided into a first compartment 76 and a second compartment 77 by the diaphragm 75. A first piping 79 continues into the inlet pipe 78 continuing to the exhaust pipe 64 shown in Fig. 22 and being provided through the case 74. A tubular catalytic body 48 having inwardly projecting deformities without holes is, as shown in Fig. 16, mounted in a cantilevered manner in the larger diameter portion 79a near the inlet of the first piping 79. The first piping 79 is bent and passes through the second compartment 77, and then is bent further in the first compartment 76, and is opened in the first compartment 76. The straight tubular second piping 80 passes through the diaphragm 75 and connects the first compartment 76 and the second compartment 77 in the center portion of the case 74. Further, a third piping 81 that passes from the second compartment 77 through the case 74 and opens toward the outside 34 is provided. [0051] Exhaust gas entered from the inlet pipe 78 into the muffler 65 is purified while passing through the tubular catalytic body 48 in the first piping. Purified exhaust gas is cooled, depressurized, and reduced in exhaust noise while passing though the first piping 79, the first compartment 76, and second piping 80 the second compartment 77, and the third piping 81 sequentially, and then is discharged in the air through the exit potion 82 of the third piping 81. [0052] Though the example in which the tubular catalytic body 48 having inwardly projected deformities without holes is mounted in the muffler 65 is shown in Fig. 24 and Fig. 25, it is clear that the same effect of exhaust gas purification as this example is exercised even when other types of tubular catalytic body having inwardly projected deformities with holes and without holes described in this specification is mounted in this type of muffler 65. [0053] As is described thus far in detail in conjunction with a plurality of embodiments, in the exhaust gas purification device of the present invention, a commercially available stainless tubular member as a catalytic carrier is used, and a tube having a plurality of inwardly projected deformities 35 or projected deformities with communication holes formed from the outside of the tube using the deformity forming tool and being applied with the catalyst to form a catalytic body is used. As a consequent, the following advantages are expected. (1) Since the commercially available tubular member is used, the method of manufacturing is easier in comparison with the conventional method comprising the steps of forming punched holes on the flat plate and forming the same into a pipe, and the manufacturing cost may be reduced. (2) Since the commercially available tubular member is used, a product of small diameter less than 20 mm may be manufactured at a high degree of accuracy. (3) Since an appropriate turbulence can be produced in exhaust gas flowing inside the tubular carrier by optimizing the shape of the inwardly projected deformity without hole or the inwardly projected deformity with communication hole, the rate of exhaust gas purification can be improved more than the product with punched holes of the related art. (4) The tubular catalytic body of the present invention may bear the most preferably effect by determining the height of the inwardly projected deformity so as to fall within the range of (17±5)% of the inner diameter of the tubular member, or by determining the intervals between the inwardly projected deformities adjacent in the axial direction of the tube to 20 to 30 mm. 36 (5) In the tubular catalytic body of the present invention, since the rate of purification on the inner surface of the tube is significantly higher than the rate of purification on the outer surface of the tube, the effect with respect to the cost may be improved by lowering the cost by producing a tubular catalytic body applied with catalyst only on the inner side of the pipe, reducing the amount of catalyst to apply by half, introducing exhaust gas into the interior of the same catalytic body, or allowing exhaust gas to flow only inside thereof. Especially, the effect in terms of the cost is significant in the case of the tubular catalytic body provided with internally projected deformities without holes. [Reference Numerals] A...conduit, B...conduit, C...conduit, D...conduit, G...flow of exhaust gas, L...interval of the inwardly projected deformity in the axial direction of the tube, 0.. .angle of inclination of the ridgeline located on the front side of the apex 1...tubular carrier (first embodiment), 37 2...inwardly projected deformity, 2a...ridgeline, 2b...rear edge, 3...communication hole, 4...stainless tubular member, 5... relief-grooved core metal, 5a... relief groove, 6...metallic holding block, 6a...cavity having circular cross section, 6b.. .elongated opening formed on top, 7...deformity forming tool, 7a...shared portion on the rear edge, 8... formation of a row of inwardly projected deformities, 9...rotation, 10... formation of inwardly projected deformities of the next row, 11... tubular catalytic body with inwardly projected deformities, 12...muffler, 13...outer body plate, 14... inner body plate, 15...partition plate, 16...glass wool, 17...front cap, 18.. .exhaust pipe, 19.. .rear cap outer plate, 20... rear cap inner plate, 21.. .glass wool, 22.. .rear end annular portion, 23...first diaphragm, 24...second diaphragm, 25...first compartment, 26...second compartment, 27...third compartment, 28...inlet pipe, 29.,.connecting pipe, 30...diffuser pipe serving as a catalytic body, 31...resonance pipe, 32...communication pipe, 33...communication pipe, 34...front diffuser assembly, 35.. .rear diffuser assembly, 36.. .guide pipe, 37... tubular carrier (second embodiment), 38... inwardly projected deformity, 39...communication hole, 40...tubular carrier (third embodiment), 41... inwardly projected deformity, 42...communication hole, 43...tubular carrier (fourth 38 embodiment), 44...inwardly projected deformity (without holes), 45...tubular carrier (fifth embodiment), 46...inwardly projected deformity (without holes), 47... deformity forming tool, 48...tubular catalytic body, 50...motorcycle, 51...vehicle body frame, 52...head pipe, 53...handle, 54...front fork, 55...front wheel, 56...shock absorbing device, 57...power unit, 58...rear wheel, 59.. .internal combustion engine, 60.. .cylinder head, 61...intake pipe, 62...carburetor, 63...air cleaner, 64...exhaust pipe, 65...muffler, 66...front cover, 67...body cover, 68...seat, 69...spare tire, 70...flange portion, 71...bracket, 72...bracket, 73...heat shield plate, 74...muffler case, 75...diaphragm, 76...first compartment, 77...second compartment, 78...intake pipe, 79.. .first piping, 79a.. .large diameter portion of the first piping, 80...second piping, 81...third piping, 82...exit portion, 01...tubular carrier, 02...punched hole, 03... rolled metal plate material, 04...punched hole process, 05...cutting, 06...U-bent process, 07...O-bent process, 08...welding, 09...tubular catalytic body with punched holes. 39 WE CLAIM: 1. An exhaust gas purification device comprising a tubular catalytic body produced by applying catalyst on the tubular carrier (1, 37, 43, 45) installed in an exhaust gas passage for purifying gas, characterized in that the tubular carrier (1, 37, 43, 45) is a tube material obtained by cutting a steel pipe member formed by extrusion or the like into a prescribed length and formed with a number of inwardly projected deformities (38, 41, 44, 46). 2. An exhaust gas purification device as claimed in claim 1, characterized in that the tubular carrier (1, 37, 43, 45) is positioned inside the resonance tube and formed with communication holes in alignment with the rear end of the respective inwardly projected deformities (38, 41, 44, 46)to bring the inside and outside of the tube into communication with each other. 3. An exhaust gas purification device as claimed in claim 1 and claim 2, characterized in that the inwardly projected deformity (38, 41, 44, 46) forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity (38, 41, 44, 46)increases gradually from zero from the upstream end toward the downstream side. 4. An exhaust gas purification device as claimed in claim 1 and claim 2, characterized in that the inwardly projected deformity (38, 41, 44, 46) forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity (38, 41, 44, 46) increases gradually from zero from the upstream end toward the downstream side and that the portion of the space having a largest cross sectional area is at the rear end of the inwardly projected deformity (38, 41, 44, 46). -40- 5. An exhaust gas purifying apparatus as claimed in claim 1 and claim 2, characterized in that the inwardly projected deformity (38, 41, 44, 46) forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity (38, 41, 44, 46) increases gradually from zero from the upstream end toward the downstream side and decreases relatively suddenly from the portion having the largest cross sectional area toward the downstream side until it reaches zero. 6. An exhaust gas purification device as claimed in claim 4 and claim 5, characterized in that the angle formed between the ridgeline of the inwardly projected deformity (38, 41, 44, 46) and the original wall surface of the tube of the inwardly projected deformity (38, 41, 44, 46) forms an acute angle. 7. An exhaust gas purification device as claimed in claim 4 and claim 5, characterized in that the height of the inwardly projected deformity (38, 41, 44, 46) is within the range of (17±5)% of the inner diameter of the tubular member. 8. An exhaust gas purification device as claimed in claim 4 and claim 5, characterized in that the inwardly projected deformities (38, 41, 44, 46) are formed in row at regular intervals in the axial direction of the tube of the tubular carrier (1, 37, 43, 45), and the distance between the inwardly projected deformities (38, 41, 44, 46) adjacent in the axial direction of the tube is 20mm to 30 mm, and a plurality of rows of the aforementioned rows are formed on a single tubular carrier (1, 37, 43, 45). 9. An exhaust gas purification device according to claim 1 to claim 8, characterized in that the tubular catalytic body is applied with catalyst only on the inner surface of the tubular carrier (1, 37, 43, 45). -41 - 10. An exhaust gas purification device as claimed in claim 1 to claim 9, characterized in that the tubular catalytic body of the exhaust gas

Full Text

FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
COMPLETE SPECIFICATION
[See Section 10]
"EXHAUST GAS PURIFICATION DEVICE"
HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan
The following specification particularly describes the nature of the invention and the manner in which it is to be performed :-

The present invention relates to exhaust gas purification device.
2-
i
The present invention relates to an exhaust gas purification device for a small internal combustion engine used for motorcycles or the like. In this specification, the term "tube material" represents material for producing a carrier by deformation process, the term "tubular carrier" represents

a target object for applying catalyst formed by deforming or punching the tube material, and the term "tubular catalytic body" represents the tubular carrier with catalyst applied thereon.
[0002]
[Description of the Related Art]
The exhaust gas purification device for a small internal combustion engine used for motorcycles or the like is a device comprising a structure obtained by applying and holding catalyst on a carrier, so called catalytic body installed in a flow of exhaust gas for purifying harmful components contained in exhaust gas. The configuration of the carrier generally used is the tubular carrier 01 formed with punched holes 02 as shown in Fig. 26 and applied with catalyst, which is disposed in parallel with the flow G of exhaust gas (Japanese Laid-Open No. 30432/1998).
[0003]
In the related art, as shown in Fig. 27, such tubuiar carrier 01 with punched holes is formed by rolling out the rolled metal plate material 03 into a flat plate, performing punched hole process 04, cutting into a prescribed size 05, performing bending process such as U-bend process 06, O-bend process 07 or the like, bringing both edges into contact, and welding 08 them.
[0004]
3

[Problems to be Solved by the Invention]
In the process of manufacturing the tubular carrier 01 in the related art as shown in Fig. 27, many numbers of processes are needed, and thus the manufacturing cost is disadvantageously increased. When using it for motorcycles of small air volume displacement, for example, of four-stroke, 125 cc or less displacement, it is difficult to decrease the diameter for mounting it into the narrow exhaust system, especially when manufacturing the tubular carrier of less than 20 mm in diameter in the method of related art, a problem that the accuracy in dimension is lowered may arise.
[0005]
When the tubular catalytic body 09 with punched holes manufactured by applying catalyst on the inner and outer surfaces of the tubular carrier 01 with punched holes in the related art is placed in a flow of exhaust gas, there arise a problem that the catalyst body must be upsized in order to secure sufficient contact between exhaust gas G and catalyst because turbulence of gas flow rarely occurs as shown in Fig. 28 since the surface of the tube is smooth.
[0006]
The present invention is intended to enable manufacturing of a tubular carrier of small diameter as described above at low manufacturing cost and high degree of accuracy, and to improve purifying capability of the exhaust
4

gas purification device with new ingenuity in configurations.
[0007]
[Means for Solving the Problems and Effects]
The present invention is intended to solve the aforementioned problems, and the invention as set forth in Claim 1 is an exhaust gas purification device comprising a tubular catalytic body produced by applying catalyst on the tubular carrier installed in an exhaust gas passage for purifying gas, characterized in that the tubular carrier is a tube material obtained by cutting a steel pipe member formed by extrusion or the like into a prescribed length and formed with a number of inwardly projected deformities.
[0008]
With the present invention constructed as described above, since the tube material may be a tube which is commercially available as a pre-molded tube, and the inwardly projected deformities can be formed easily from the outside of the tube, the number of manufacturing process may be reduced and thus the manufacturing cost may also be reduced. When the commercially available tube material is used, the tube having diameter less than 20 mm may also be produced with a high degree of accuracy. In addition, since optimization of the configuration of the projected deformities may generate turbulence in exhaust gas flowing inside the tubular catalytic body, downsizing of the catalytic body and improvement of
5

exhaust gas purification rate may be realized.
[0009]
The invention as set forth in Claim 2 is an exhaust gas purification device according to Claim 1, characterized in that the tubular carrier is positioned inside the resonance tube and formed with communication holes adjacent to the rear end of the respective inwardly projected deformities to bring the inside and outside of the tube into communication with each other.
[0010]
With the present invention constructed as described above, optimization of the configuration of the projected deformities with communication holes may generate turbulence in exhaust gas flowing inside the catalytic body, and reduction of the amount of gas leaking outside may reduce effects on exhaust pulsation, whereby performance of the internal combustion engine as well as purifying rate of exhaust gas may be improved.
[0011]
The invention as set forth in Claim 3 is an exhaust gas purification device according to Claim 1 and Claim 2, characterized in that the inwardly projected deformity forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity increases gradually from zero from the

6

upstream end toward the downstream side. With the present invention in this arrangement, increase in resistance with respect to gas flow may be alleviated.
[0012]
The invention as set forth in Claim 4 is an exhaust gas purification device according to Claim 1 and Claim 2, characterized in that the inwardly projected deformity forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity increases gradually from zero from the upstream end toward the downstream side and that the portion of the space having a largest cross sectional area is at the rear end of the inwardly projected deformity. Since such arrangement of the present invention causes turbulence in exhaust gas rearward of the projected deformity and thus purifying rate of exhaust gas may be improved.
[0013]
The invention as set forth in Claim 5 is an exhaust gas purifying apparatus according to Claim 1 and Claim 2, characterized in that the inwardly projected deformity forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity increases gradually from zero from the upstream end toward the downstream side and decreases relatively suddenly from the portion having the largest cross
7

sectional area toward the downstream side until it reaches zero. This means may also serve to improve purifying rate of exhaust gas since the present invention gives turbulence to exhaust gas rearward of the projected deformity.
[0014]
The invention as set forth in Claim 6 is an exhaust gas purification device according to Claim 4 and Claim 5, characterized in that the angle formed between the ridgeline of the inwardly projected deformity and the original wall surface of the tube of the inwardly projected deformity forms an acute angle. This means may also serve to improve purifying rate of exhaust gas since the present invention gives turbulence to exhaust gas rearward of the projected deformity.
[0015]
The invention as set forth in Claim 7 is an exhaust gas purification device according to Claim 4 to Claim 5, characterized in that the height of the inwardly projected
deformity is within the range of (17±5)% of the inner diameter of the tubular member. With the present invention in this arrangement, production efficiency may be improved by extremely superior processability and manuf acturability while maintaining the purifying rate of toxic gas in the constant level without specifically increasing resistance in the flow path of exhaust gas in comparison with the tubular catalytic body with punched holes in the related art.
8

[0016]
The invention as set forth Claim 8 is an exhaust gas purification device according to Claim 4 and Claim 5, characterized in that the inwardly projected deformities are formed in row at regular intervals in the axial direction of the tube of the tubular carrier, and the distance between the inwardly projected deformities adjacent in the aforementioned axial direction of the tube is 20mm to 30 mm, and a plurality of rows of the aforementioned rows are formed on a single tubular carrier. With the present invention in this arrangement, such disadvantages that the effect is lowered because the distances are too short and thus the rear inwardly projected deformities are hidden in the backlash of the inwardly projected deformities on the front portion, or that the effect is lowered because the distances are too long and thus total number of internal projecting deformities is insufficient and thus optimal intervals can be provided.
[0017]
The invention as set forth in Claim 9 is an exhaust gas purification device according to Claim 1 to Claim 8, characterized in that the tubular catalytic body is applied with catalyst only on the inner surface of the tubular carrier. The present invention utilizes that the purification effect of the inner side of the tube is significantly higher than that in the outside by the presence of the projected deformities

9

on the inner surface of the tube, and intends to reduce the cost of catalyst by applying it only on the inner surface of the tubular carrier and allowing exhaust gas to flow into the tube, thereby improving the purification effect with respect to the costs of catalyst.
[0018]
The invention as set forth in Claim 10 is an exhaust gas purification device according to Claim a to Claim 9, characterized in that the tubular catalytic body of the exhaust gas purification device is installed in the passage of the exhaust gas in the muffler of the motorcycle for purifying gas. With the present invention in this arrangement, purification of exhaust gas can be performed without adding a separate device. [Brief Description of the Drawings]
[Fig. 1]
Fig. 1 is a drawing showing a first embodiment of tubular carrier 1 according to the exhaust gas purification device of the present invention, in which (a) is a drawing of a tubular carrier 1 when viewed from obliquely behind, and (b) is a drawing of the same when viewed from the back.
[Fig. 2]
Fig. 2 shows three view of the same tubular carrier 1, in which (a) is a side view, (b) is a cross sectional view taken along the line B-B of the figure (a), and (c) is a cross sectional view taken along the line C-C of the figure (b).,
[Fig. 3]
10

Fig. 3 is a drawing showing the process of manufacturing the tubular carrier.
[Fig. 4]
Fig. 4 is a perspective view showing an inwardly projected deformity 2 and a deformity forming tool 7 for forming the same inwardly projected deformity of the tubular carrier 1 of the first embodiment, in which (a) is a view of one of inwardly projected deformities 2 when viewed from inside the tube, and (b) is a outline view of the deformity forming tool 7 to be used for deforming the inwardly projected deformity 2.
[Fig. 5]
Fig. 5 is a drawing of streamlines in a state in which the tubular catalytic body 11 with inwardly projected deformity manufactured by applying catalyst on the tubular carrier is placed in the flow of exhaust gas.
[Fig. 6]
Fig. 6 is a side view of the muffler 12 of an internal combustion engine of four-stroke, 125 cc for motorcycles to which the aforementioned catalytic body 11 is mounted.
[Fig. 7]
Fig. 7 is a lateral cross section of the muffler.
[Fig. 8]
Fig. 8 is a vertical cross section of the muffler taken along the vertical plane.
11

[Fig. 9]
Fig. 9 is a horizontal cross section of the same muffler.
[Fig. 10]
Fig. 10 is a drawing showing a tubular carrier according to the second embodiment of the exhaust gas purification device according to the present invention in which (a) is a rear perspective view of the tubular carrier, and (b) is a back view.
[Fig. 11]
Fig. 11 is a drawing showing a tubular carrier according to the third embodiment of the exhaust gas purification device according to the present invention, in which (a) is a rear perspective view of the tubular carrier, and (b) is a back view.
[Fig. 12]
Fig. 12 is a drawing showing a tubular carrier according to the fourth embodiment of the exhaust gas purification device of the present invention, in which (a) is a rear perspective view of the tubular carrier, and (b) is a back view.
[Fig. 13]
Fig. 13 shows three surfaces of the tubular carrier according to the fifth embodiment of the exhaust gas purification device of the present invention, in which (a) is a side view, (b) is a cross sectional view taken along the line B-B in the figure (a), and (c) is a crose sectional view taken along the line C-C in the figure (b).
[Fig. 14]

12

Fig. 14 is a perspective view showing the configuration of the inwardly projected deformity 46 and the deformity forming tool 47 for processing the inwardly projected deformity of the tubular carrier 45 of the fifth embodiment, in which (a) is a drawing of a single inwardly projected deformity 46 viewed from inside the tube, and (b) is a outline view of the deformity forming tool 47 used for deforming the inwardly projected deformity 46.
[Fig. 15]
Fig. 15 is a perspective outline view of the tubular carrier according to the fifth embodiment provided with a variety of numbers of rows of inwardly projected deformities.
[Fig. 16]
Fig. 16 is a drawing of streamlines in a state in which exhaust gas flow G is introduced into the interior of the tubular catalytic body 48 formed by applying catalyst on the inner surface of the tube of the tubular carrier 45 with inwardly projected deformities 46 without hole in the fifth embodiment.
[Fig. 17]
Fig. 17 is a drawing showing definitions of the inner diameter of the tubular carrier in the fifth embodiment and of the height of the inwardly projected deformities.
[Fig. 18]
Fig. 18 shows a result of an experiment on the gas
13

purification rates (%) of the tubular catalytic body 48 that are formed by providing inwardly projected deformities of 1 mm, 4mm, and 7mm in height on the tubular members of 23.4 mm in inner diameter. The gas purification rate (%) of the tubular catalytic body 09 having punched holes of the identical inner diameter is also shown.
[Fig. 19]
Fig. 19 shows a result of an experiment on the resistance in the flow path (Pa) in the tubular catalytic body 48 under the same conditions as Fig. 18. The resistance of the flow path (Pa) of the tubular catalytic body 09 with punched holes of the identical inner diameter is also shown.
[Fig. 20]
Fig. 20 shows these results of the experiments altogether, showing the height (mm) of the preferable inwardly projected deformity with respect to the inner diameter of the tubular member (mm), and the range of tolerance thereof.
[Fig. 21]
Fig. 21 is a side view of a motorcycle 50 provided with the tubular catalytic body of the fifth embodiment.
[Fig. 22]
Fig. 22 is a side view of the exhaust pipe 64 and the muffler 65.
[Fig. 23]
Fig. 23 is a plan view.
14

[0019]
[Detailed Description of Preferred Embodiments] Fig. 1 is shows an embodiment of the tubular carrier for an exhaust gas purification device according to the present invention, in which (a) is a drawing of a tubular carrier 1 when viewed from.obliquely behind, and (b) is a drawing of the same when viewed from the right back. The tubular member is formed on its periphery with a number of inwardly projected deformities 2 formed by deforming the tubular member itself inwardly so as to project therefrom. One side of each projected deformity is shared and punched to form a
15

communication hole 3, through which the outside and the inside of the tube is communicated. The arrow G represents the direction of the flow of exhaust gas.
[0020]
Fig. 2 shows three view of the same tubular carrier, in which (a) is an outline view when viewed from the side, (b) is a cross sectional view taken along the line B-B of the figure (a), and (c) is a cross sectional view (viewed toward the front) taken along the line C-C of the figure (b). When viewed from the outside of the tube, the configuration of the inwardly projected deformity 2 is a triangular recess, and when viewed from the back toward the front, a triangular communication hole 3 formed on one side of each inwardly projected deformity by sharing and punching the tubular member can be seen. When using this carrier, it is arranged so that exhaust gas flows from the left to the right, and thus the inwardly projected deformity 2 is formed at a slant such that the triangular communication hole 3 described above opens toward the rear. The angle of inclination 9 is preferably about 30 degrees.
[0021]
Fig. 3 is a drawing showing the process of manufacturing the same tubular carrier. A stainless pipe member 4 precut into a required length, which is commercially available, is used as material for manufacturing the carrier of this embodiment. A relief-grooved core metal 5 formed with rows
16

of a plurality of recessed grooves corresponding to the rows of inwardly projected deformities which will be formed along the generating line of the tubular member, so called relief grooves 5a, is inserted into the precut tubular member 4 described above, and in this state, is inserted into the metallic holding block 6 formed with an elongated cavity 6a having circular cross section at the center thereof and an elongated opening 6b formed on top thereof. Subsequently, the deformity forming tool 7 is abutted against the outer peripheral surface of the tubular member 4 at the positions corresponding to the relief grooves 5a described above and knocked therein from the opening 6b on top. When formation of a row of inwardly projected deformities 8 is finished, the deformity forming tool 7 is withdrawn upward, the tubular member 4 and the core metal 5 are rotated 9 together for the formation of inwardly projected deformities of the next row 10. By repeating these procedures and forming inwardly projected deformities 2 along the entire circumference of the tubular member 4, a tubular carrier 1 is completed. When the catalyst is applied on it, a tubular catalytic body is completed.
[0022]
Fig. 4 is a perspective view showing an inwardly projected deformity 2 and a deformity forming tool 7 for processing the same inwardly projected deformity, in which (a)
17

is a view of one of inwardly projected deformities 2 when viewed from inside the tube, and (b) is a outline view of the deformity forming tool 7 to be used for processing the inwardly projected
deformity 2. The angle 0 between the ridgeline 2a of the inwardly projected deformity 2 and the original wall surface of the tube forms an acute angle, and preferably about 30 degrees. In order to shear the rear edge 2b of the deformity 2, the edge of the rear edge sharing portion 7a of the deformity forming tool 7 is formed with a sharp blade.
[0023]
Pig. 5 is a drawing of streamlines in a state in which the tubular catalytic body 11 with inwardly projected deformity 2 manufactured by applying catalyst on the tubular carrier 1 of the embodiment described above is placed in the flow of exhaust gas G. In the tubular catalytic body 11 with inwardly projected deformity, since a heavy turbulence occurs on the inner surface of the tube at the rear end of the inwardly projected deformity, and exhaust gas, being swirling, is brought into heavy contact with the catalyst applied on the carrier, the effect of exhaust gas purification is significantly higher than the case of the tubular catalytic body 09 with punched holes in the related art in which the laminar flow of gas flows along the surface (See Fig. 28).
[0024]
Subsequently, an embodiment in which the aforementioned
18

tubular catalytic body 11 with inwardly projected deformity is applied to the exhaust system of the motorcycle will be described. Fig. 6 is a side view of the muffler 12 of an internal combustion engine of four-stroke, 125 cc for motorcycles to which the aforementioned catalytic body 11 is mounted, and Fig. 7 is a lateral cross section of the same muffler (cross section taken along the line VII-VII in Fig. 6 and viewed from the rear). As shown in Fig. 7, four conduits A, B, C, and D are provided within the muffler 12. Fig. 8 is a vertical cross section of the muffler taken along the vertical plane (cross section taken along the line VIII-VIII in Fig. 7). Fig. 9 is a horizontal cross section (taken along the line IX-IX in Fig. 7)
[0025]
In Fig. 8 and Fig. 9, the central portion of the body of the muffler 12 has a dual body comprising outer body plate 13 and the inner body plate 14, which are held with each other by the partition plate 15 with gap filled with glass wool 16. The front portion of the body is covered by the semi-spherical front cap 17, into which an exhaust pipe 18 which continues into the internal combustion engine is inserted. The rear portion of the body is covered by the rear cap outer plate 19 and the rear cap inner plate 20, which are filled with glass wool 21 therebetween. A rear end annular portion 22 is provided on the rear surface of the rear cap. Inside of the
19

inner body plate 14, there are provided a first diaphragm 23 and a second diaphragm 24 in order from the front, which divide the interior of the muffler 12 into three compartments. These compartments are referred to as the first compartment 25, the second compartment 26, and the third compartment 27 in order from the front for the purpose of explanation below. In the muffler, there are provided four conduits A, B, C, and D being different in length for communicating the respective compartments 25, 26, 27 in different combinations.
[0026]
The conduit A located at the upper portion in the muffler comprises, as shown in Fig. 8, an inlet tube 28 continuing to the exhaust pipe 18 located outside, a connecting pipe 29 continuing to the inlet pipe 28, a diffuser pipe serving as a catalytic body 30 continuing to the connecting pipe 29, and a resonance pipe 31 covering the outside of the diffuser pipe serving as a catalytic body 30. The conduit A passes through the first diaphragm 23 and the second diaphragm 24, and exhaust gas discharged from the internal combustion engine passes through the conduit A and injected firstly into the third compartment 27.
[0027]
In Fig. 9, the conduit B on the right side in the muffler comprises a communication pipe 32. The conduit B passes through the second diaphragm 24, and exhaust gas previously
20

injected into the third compartment 27 passes through the conduit B and enters into the second compartment 26.
[0028]
In Fig. 9, the conduit C on the left side of the muffler comprises a communication pipe 33. The conduit C passes through the first diaphragm 23, and exhaust gas previously entered into the second compartment 26 passes through the same conduit C and enters into the first compartment 25.
[0029]
In Fig. 8, the conduit D located at the lower portion in the muffler comprises a front diffuser assembly 34 and the rear diffuser assembly 35, which are connected by the guide pipe 36 with each other. The conduit D passes through the first diaphragm 23 and the second diaphragm 24, and then through the rear cap outer plate 19 and the rear cap inner plate 20 at the rear end portion of the rear diffuser assembly 35, and is projected to the outside. Exhaust gas previously entered into the first compartment 25 is discharged to the outside through the conduit D. The muffler 12 is a device for lowering the exhaust sound by means of capability of discharging exhaust gas of the internal combustion engine through the complex passages as described above, and of the action as diffusers 30, 34, 35.
[0030]
The diffuser pipe serving as a catalytic body 30, being
21

one of the applications of the aforementioned tubular catalytic body 11, is a tubular catalytic body 11 having inwardly projected deformities obtained by applying catalyst on the tubular carrier 1 provided with the inwardly projected deformities as shown in Fig. 1 placed at the end of the conduit A continuing directly to the exhaust pipe 18 in the muffler 12 where a dif fuser pipe provided with a number of punched hole was situated in the related art instead of the same diffuser pipe. The diffuser pipe of the related art is adapted to damp the pressure energy when exhaust gas is flown through a number of punched holes, and generates sound deadening effects with interaction with the resonance pipe located outside, thereby lowering the sound volume. Since the tubular catalytic body 11 of this embodiment is provided with a number of communication holes 3 on the periphery thereof, it can function as a diffuser pipe serving as a catalytic body 30 having a sound deadening capability instead of the diffuser pipe with punched holes in the related art.
[0031]
In the diffuser pipe serving as a catalytic body 30 of this embodiment, exhaust gas is introduced from the connecting pipe 29 so that gas flows inside the tube. The main flow of gas flows within the pipe, and a small quantity of gas flows outside the tube. Therefore, even when the tube applied with the catalyst only on the inner side thereof is used, the effects
22

that bear comparison with the tube applied with the catalyst on the outer and inner sides thereof can be produced. In this arrangement, the cost required for manufacturing catalysts can be reduced by half, and thus a large effect in terms of cost can be obtained.
[0032]
Fig. 10 is a drawing showing a tubular carrier 37 according to the second embodiment of the exhaust gas purification device according to the present invention. The inwardly projected deformity 38 of this embodiment has a round portion at the front and communication hole 39 linearly shared and punched at the rear end. The effects of this embodiment are almost the same as the tubular carrier of the first embodiment.
[0033]
Fig. 11 is a drawing showing a tubular carrier 40 according to the third embodiment of an exhaust gas purification device according to the present invention. The inwardly projected deformity 41 of this embodiment has a shape formed by forming a shared and punched hole 42 elongated in the direction of the axis of the tube and bending the tubular member material inwardly of the tube about the side which is not punched. Gas is communicated between the outside and the inside of the tube through shared and punched holes 42 elongated in the direction of axis of the tube. in the tubular carrier

23

according to this embodiment, the catalyst is applied both on the inner and outer sides of the tube so as to allow gas to come into contact with both surfaces effectively.
[0034]
Fig. 12 is a drawing showing a tubular carrier 43 according to the fourth embodiment of the exhaust gas purification device of the present invention. The inwardly projected deformity 44 of this embodiment is round as a part of a spherical surface, and there is no hole for communicating the inside and the outside of the tube. The tubular carrier of this embodiment can be applied to the exhaust gas purification device of the type in which exhaust gas is flown only along the inner surface of the tube.
[0035]
Fig. 13 shows three surfaces of the tubular carrier 45 according to the fifth embodiment of the exhaust gas purification device according to the present invention, in which (a) is an outline view shown from the side, (b) is a cross sectional view taken along the line B-B in the figure (a), and (c) is a cross sectional view taken along the line C-C in the figure (b) (when viewed toward the front). The configuration of the inwardly projected deformity 46 is a rounded trapezoidal recess when viewed from the outside the tube, and no hole that communicates the inside and the outside of the tube is provided. When viewed from the rear toward the front, the inwardly
24

deformed deformity 46 formed by deformation of the tubular member can be seen. When using this carrier, it is disposed so that exhaust gas flows in the tube as shown in the direction of the arrow G.
[0036]
Fig. 14 is a perspective view showing the configuration of the inwardly projected deformity 46 of the tubular carrier 45 according to Claim 5 and the deformity forming tool 47 for processing the inwardly projected deformity 46, in which (a) is a drawing of a single inwardly projected deformity 46 viewed from inside of the tube, and (b) is a outline view of the deformity forming tool 47 used for deforming the inwardly projected deformity 46.
[0037]
The inwardly projected deformity 46 of this embodiment is, as shown in Fig. 14(a), pyramid shape elongated in the direction of gas flow G with inequilateral bottom surface, and inclination of the ridgeline located on the front side of the apex when viewed in the direction of gas flow with respect to the tube wall out of ridgelines extending in the fore-and-aft direction is more gentle in comparison with inclination of the ridgelines on the backside of the apex with respect to the tube wall. The angle of the ridgeline on the front side
of the apex with respect to the tube wall designated by 9 is an acute angle, which is preferably in the order of 30 degrees.
25

The portion near the apex is the portion of the largest cross sectional area, and the lateral cross sectional area decreases relatively suddenly from the portion of the largest cross sectional area toward the downstream to zero. Though the apex, ridgelines, and the like are shown in sharp lines in the figure, they are formed into the rounded shape in practice.
[0038]
Fig. 14(b) is an perspective outline view of the deformity forming tool 47 for machining the inwardly projected deformity 46. In the deformity forming tool in practical use, the apex and the edges along the ridgelines are rounded so as to prevent the tubular member from being scratched. Inclination of the front ridgeline with respect to the tube wall is preferably in the order of 30 degrees as described above. The process of manufacturing the tubular carrier 45 using the deformity forming tool 47 is the same as the process of manufacturing the tubular carrier 1 shown in Fig. 3.
[0039]
Fig. 15 is a perspective outline view of the tubular carrier according to the fifth embodiment provided with a variety of numbers of rows of inwardly projected deformities. This embodiment may be formed by forming two to six, or some other plural number of rows of the inwardly projected deformities in the axial direction of the tubular carrier at regular intervals. Forming an even number of rows,
26

positioning the opposed rows at the symmetrical positions with respect to the centerline of the tube, and machining the inwardly projected deformities on the opposed rows simultaneously from above and below for example with a suitable tool may improve the manufacturing efficiency of the tubular carrier.
[0040]
Fig. 16 is a drawing of streamlines in a state in which exhaust gas flow G is introduced in the tubular catalytic body 48 formed by applying catalyst on the inner surface of the tube of the tubular carrier 45 with inwardly projected deformities 46 without hole in this embodiment. In the example shown in the figure, the tubular catalytic body 48 is held in a cantilevered manner, and exhaust gas is not flowing outside the tube. In this tubular catalytic body 48, since the lateral cross sectional area decreases relatively suddenly from the portion of largest lateral cross sectional area of the inwardly projected deformity 46 toward the downstream side, and finally the lateral cross sectional area of the projected portion becomes zero, a heavy turbulence occurs on the inner surface of the tube and at the rear end of the inwardly projected deformity. Since exhaust gas is heavily brought into contact with catalyst applied on the inner surface of the carrier by this turbulent phenomenon, the effect of exhaust gas purification is significantly high with respect to the tubular
27

catalytic body 09 with punched holes in the related art in which gas flow flows on the surface laminarly (Fig. 28).
[0041]
The tubular catalytic body 11 having inwardly projected deformities 2 with holes shown in Fig. 5 is used in such a manner that the tube is applied with catalyst on the inner side and the outer side and exhaust gas is allowed to flow inside and outside the tube through the holes. Since the same amount of catalyst is applied on the outer surface as well as on the inner surface regardless of the fact that the amount of gas flown on the outer surface of the tube is smaller with respect to that flown on the inner surface of the tube, the amount of catalyst to be used on the outer surface is almost the same amount as that to be used on the inner surface so that a high effect cannot be expected in terms of the effect with respect to the cost. The tubular catalytic body 48 having inwardly projected deformities 46 without holes according to the fifth embodiment shown in Fig. 16 is improvement thereof, in which catalyst is applied only on the inner surface of the tube and exhaust gas is allowed to flow only through the inside of the tube. Securing the contact surface between exhaust gas and catalyst may be adjusted by slightly increasing the length of the tube, and so on. [0042] The higher the internal projected deformity is, the more
28

the rate of purifying harmful substances increases. However, since the inwardly projected deformities block the flow path of gas simultaneously, the resistance in the flow path increases, and thus lowering of the output of the internal combustion engine occurs. In order to put the present invention into practical use, it is required to realize the purification rate and resistance in the flow path at least in the same level as the tubular catalytic body 09 having punched holes in the related art (Fig. 28) . Therefore, an experiment for obtaining the optimal interrelation between the internal diameter of the tubular member and the height of the inwardly projected deformity was conducted. A part of it will be described below.
[0043]
Fig. 17 is a drawing showing definitions of the inner diameter of the tubular member of the material of the tubular carrier 45 in the fifth embodiment and of the height of the inwardly projected deformities after machining. Fig. 18 shows a curve connecting plotted points representing the gas purification rates (%) of the tubular catalytic body 48 that are formed by providing inwardly projected deformities of 1 mm, 4mm, and 7mm in height on the tubular members of 23.4 mm in inner diameter, and Fig. 19 shows a curve connecting plotted points representing the resistance in the flow path (Pa) in the tubular catalytic body 48 under the same conditions. In
29

these figures, the gas purification rate (%) and the resistance of the flow path (Pa) of the tubular catalytic body 09 with punched holes having the same inner diameter as the aforementioned tubular catalytic body 48 are shown in the respective figures for the sake of comparison. Since the tubular catalytic body 09 with punched holes is nothing to do with the height of the inwardly projected deformities, it is shown as a constant value.
[0044]
From these figures, when the tubular member of 23.4 mm in inner diameter was used, the tubular catalytic body 48 having inwardly projected deformities being 4 mm in height is as almost equal to the tubular catalytic body 09 with punched holes of identical inner diameter in terms of performance regarding exhaust gas purification rate (%) and resistance in the flow path (Pa), and when the height of the inwardly projected deformity exceeded 4 mm, the resistance in the flow path (Pa) suddenly increases regardless of the fact that the exhaust gas purification rate (%) did not increase that much, while the height of the inwardly projected deformity was lower than 4 mm, the exhaust gas purification rate (%) suddenly decreased, but the resistance in the flow path (Pa) did not decrease much as a consequent. From these results of the experiment, the results was such that the preferably height of the inwardly projected deformity was in the range of (17±5)% of the inner
30

diameter of the tubular member, considering the tolerable range. The range of the height of the inwardly projected deformity when the tubular member of 23.4 mm in inner diameter is used is the range approximately between 2.8 mm and 5.2 mm.
[0045]
As a result of the same experiment conducted also on the tubular catalytic bodies having some other diameters, it was found that the preferable height of the inwardly projected
deformity was (17±5)% of the inner diameter of the tubular member even when the tubular members are different in inner diameter. Fig. 20 shows these results of the experiments altogether, in which the horizontal axis represents the inner diameter of the tubular member (mm) and the vertical axis represents the height of the inwardly projected deformity (mm). The optimal height of the inwardly projected deformity is represented by a thick solid line, and the limit of the tolerable range is represented by a thin solid line. With the present embodiment in this arrangement, production efficiency may be improved by extremely superior processability and manufacturability while maintaining the purifying rate of toxic gas in the constant level without specifically increasing resistance in the flow path of exhaust gas in comparison with the tubular catalytic body with punched holes in the related art. [0046]
31

In the tubular catalytic body of the present embodiment, it was found that the inwardly projected deformities were formed in row in the axial direction of the tube, and the distance L (See Fig. 15) between the inwardly projected deformities 46 adjacent in the axial direction of the tube was preferably between 20 and 30 mm. When the intervals are too short, the effect is lowered because the rear inwardly projected deformities are hidden in the backlash of the inwardly projected deformities on the front portion. While when the intervals are too long, the effect is lowered due to insufficient number of internal projecting deformities. By employing the aforementioned intervals, such drawback may be prevented.
[0047]
The above described experiment was conducted also on the inwardly projected deformities with holes as shown in Fig. 2 and so on, and it was verified that the results of the aforementioned experiment that the height of the inwardly
projected deformity was preferably within the range of (17±5) % of the inner diameter of the tubular member, and that the dimension of the distance between the inwardly projected deformities adjacent in the axial direction of the tube is preferably between 20 and 30 mm can be applied to the inwardly projected deformities of some other configurations. [0048]
32

Fig. 21 is a side view of a motorcycle 50 provided with the tubular catalytic body of the present embodiment. A head pipe 52 is provided at the front end of the vehicle body frame 51, on which a handle 53 and a front fork 54 are rotatably held, and a front wheel 55 is rotatably supported by the front fork 54. The upper end of a shock absorbing device 56 is mounted at the rear portion of the vehicle body frame 51, a power unit 57 is suspended between the center portion of the vehicle body frame 51 and the lower end of the shock absorbing device 56, and a rear wheel 58 is rotatably mounted on the rear portion of the power unit 57. The carburetor 62 and the air cleaner 63 are connected to the cylinder head 60 of the internal combustion engine 59 constituting the front portion of the power unit 57 via an air intake pipe 61, and a muffler 65 is connected to the same cylinder head 60 via an exhaust pipe 64. In the figure, the exhaust pipe 64 and the muffler 65 are disposed on the far side of the vehicle body, and thus they are shown by broken hatching so as to demonstrate the position clearly. The vehicle body frame 51, the internal combustion engine 59, and the like are covered by the front cover 66, the body cover 67, and the like. A seat 68 is provided on the upper portion of the body cover 67. A spare tire 69 is provided on the rear portion of the body cover 67.
[0049]
Fig. 22 is a side view of the exhaust pipe 64 and the
33

muffler 65, and Fig. 23 is a plan view thereof. The front end of the exhaust pipe 65 is provided with a flange portion 70 for connecting it to the cylinder head 60, and the muffler 65 is provided with two brackets 71, 72 for mounting it to the structural portion of the power unit 57. A heat shield plate 73 is provided on the side surface of the muffler.
[0050]
Fig. 24 is a side view showing the interior of the muffler 65, and Fig. 25 is a plan view showing the interior of the same muffler. The muffler 65 is covered by a case 74, and the interior thereof is divided into a first compartment 76 and a second compartment 77 by the diaphragm 75. A first piping 79 continues into the inlet pipe 78 continuing to the exhaust pipe 64 shown in Fig. 22 and being provided through the case 74. A tubular catalytic body 48 having inwardly projecting deformities without holes is, as shown in Fig. 16, mounted in a cantilevered manner in the larger diameter portion 79a near the inlet of the first piping 79. The first piping 79 is bent and passes through the second compartment 77, and then is bent further in the first compartment 76, and is opened in the first compartment 76. The straight tubular second piping 80 passes through the diaphragm 75 and connects the first compartment 76 and the second compartment 77 in the center portion of the case 74. Further, a third piping 81 that passes from the second compartment 77 through the case 74 and opens toward the outside
34

is provided.
[0051]
Exhaust gas entered from the inlet pipe 78 into the muffler 65 is purified while passing through the tubular catalytic body 48 in the first piping. Purified exhaust gas is cooled, depressurized, and reduced in exhaust noise while passing though the first piping 79, the first compartment 76, and second piping 80 the second compartment 77, and the third piping 81 sequentially, and then is discharged in the air through the exit potion 82 of the third piping 81.
[0052]
Though the example in which the tubular catalytic body 48 having inwardly projected deformities without holes is mounted in the muffler 65 is shown in Fig. 24 and Fig. 25, it is clear that the same effect of exhaust gas purification as this example is exercised even when other types of tubular catalytic body having inwardly projected deformities with holes and without holes described in this specification is mounted in this type of muffler 65.
[0053]
As is described thus far in detail in conjunction with a plurality of embodiments, in the exhaust gas purification device of the present invention, a commercially available stainless tubular member as a catalytic carrier is used, and a tube having a plurality of inwardly projected deformities
35

or projected deformities with communication holes formed from the outside of the tube using the deformity forming tool and being applied with the catalyst to form a catalytic body is used. As a consequent, the following advantages are expected.
(1) Since the commercially available tubular member is used, the method of manufacturing is easier in comparison with the conventional method comprising the steps of forming punched holes on the flat plate and forming the same into a pipe, and the manufacturing cost may be reduced.
(2) Since the commercially available tubular member is used, a product of small diameter less than 20 mm may be manufactured at a high degree of accuracy.
(3) Since an appropriate turbulence can be produced in exhaust gas flowing inside the tubular carrier by optimizing the shape of the inwardly projected deformity without hole or the inwardly projected deformity with communication hole, the rate of exhaust gas purification can be improved more than the product with punched holes of the related art.
(4) The tubular catalytic body of the present invention may bear the most preferably effect by determining the height of the inwardly projected deformity so as to fall within the range of (17±5)% of the inner diameter of the tubular member, or by determining the intervals between the inwardly projected deformities adjacent in the axial direction of the tube to 20 to 30 mm.
36

(5) In the tubular catalytic body of the present invention, since the rate of purification on the inner surface of the tube is significantly higher than the rate of purification on the outer surface of the tube, the effect with respect to the cost may be improved by lowering the cost by producing a tubular catalytic body applied with catalyst only on the inner side of the pipe, reducing the amount of catalyst to apply by half, introducing exhaust gas into the interior of the same catalytic body, or allowing exhaust gas to flow only inside thereof. Especially, the effect in terms of the cost is significant in the case of the tubular catalytic body provided with internally projected deformities without holes.
[Reference Numerals]
A...conduit, B...conduit, C...conduit, D...conduit, G...flow of exhaust gas, L...interval of the inwardly projected deformity in the axial direction of the tube,
0.. .angle of inclination of the ridgeline located on the front side of the apex 1...tubular carrier (first embodiment),
37

2...inwardly projected deformity, 2a...ridgeline, 2b...rear edge, 3...communication hole, 4...stainless tubular member, 5... relief-grooved core metal, 5a... relief groove, 6...metallic holding block, 6a...cavity having circular cross section, 6b.. .elongated opening formed on top, 7...deformity forming tool, 7a...shared portion on the rear edge, 8... formation of a row of inwardly projected deformities, 9...rotation, 10... formation of inwardly projected deformities of the next row, 11... tubular catalytic body with inwardly projected deformities, 12...muffler, 13...outer body plate, 14... inner body plate, 15...partition plate, 16...glass wool, 17...front cap, 18.. .exhaust pipe, 19.. .rear cap outer plate, 20... rear cap inner plate, 21.. .glass wool, 22.. .rear end annular portion, 23...first diaphragm, 24...second diaphragm, 25...first compartment, 26...second compartment, 27...third compartment, 28...inlet pipe, 29.,.connecting pipe, 30...diffuser pipe serving as a catalytic body, 31...resonance pipe, 32...communication pipe, 33...communication pipe, 34...front diffuser assembly, 35.. .rear diffuser assembly, 36.. .guide pipe, 37... tubular carrier (second embodiment), 38... inwardly projected deformity, 39...communication hole, 40...tubular carrier (third embodiment), 41... inwardly projected deformity, 42...communication hole, 43...tubular carrier (fourth
38

embodiment), 44...inwardly projected deformity (without holes), 45...tubular carrier (fifth embodiment), 46...inwardly projected deformity (without holes), 47... deformity forming tool, 48...tubular catalytic body, 50...motorcycle, 51...vehicle body frame, 52...head pipe, 53...handle, 54...front fork, 55...front wheel, 56...shock absorbing device, 57...power unit, 58...rear wheel, 59.. .internal combustion engine, 60.. .cylinder head, 61...intake pipe, 62...carburetor, 63...air cleaner, 64...exhaust pipe, 65...muffler, 66...front cover, 67...body cover, 68...seat, 69...spare tire, 70...flange portion, 71...bracket, 72...bracket, 73...heat shield plate, 74...muffler case, 75...diaphragm, 76...first compartment, 77...second compartment, 78...intake pipe, 79.. .first piping, 79a.. .large diameter portion of the first piping, 80...second piping, 81...third piping, 82...exit portion, 01...tubular carrier, 02...punched hole, 03... rolled metal plate material, 04...punched hole process, 05...cutting, 06...U-bent process, 07...O-bent process, 08...welding, 09...tubular catalytic body with punched holes.
39

WE CLAIM:
1. An exhaust gas purification device comprising a tubular catalytic body produced by applying catalyst on the tubular carrier (1, 37, 43, 45) installed in an exhaust gas passage for purifying gas, characterized in that the tubular carrier (1, 37, 43, 45) is a tube material obtained by cutting a steel pipe member formed by extrusion or the like into a prescribed length and formed with a number of inwardly projected deformities (38, 41, 44, 46).
2. An exhaust gas purification device as claimed in claim 1, characterized in that the tubular carrier (1, 37, 43, 45) is positioned inside the resonance tube and formed with communication holes in alignment with the rear end of the respective inwardly projected deformities (38, 41, 44, 46)to bring the inside and outside of the tube into communication with each other.
3. An exhaust gas purification device as claimed in claim 1 and claim 2, characterized in that the inwardly projected deformity (38, 41, 44, 46) forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity (38, 41, 44, 46)increases gradually from zero from the upstream end toward the downstream side.
4. An exhaust gas purification device as claimed in claim 1 and claim 2,
characterized in that the inwardly projected deformity (38, 41, 44, 46) forms
such space that the lateral cross sectional area defined between the original
wall surface of the tube and the inwardly projected deformity (38, 41, 44, 46)
increases gradually from zero from the upstream end toward the
downstream side and that the portion of the space having a largest cross
sectional area is at the rear end of the inwardly projected deformity (38, 41,
44, 46).
-40-

5. An exhaust gas purifying apparatus as claimed in claim 1 and claim 2, characterized in that the inwardly projected deformity (38, 41, 44, 46) forms such space that the lateral cross sectional area defined between the original wall surface of the tube and the inwardly projected deformity (38, 41, 44, 46) increases gradually from zero from the upstream end toward the downstream side and decreases relatively suddenly from the portion having the largest cross sectional area toward the downstream side until it reaches zero.
6. An exhaust gas purification device as claimed in claim 4 and claim 5, characterized in that the angle formed between the ridgeline of the inwardly projected deformity (38, 41, 44, 46) and the original wall surface of the tube of the inwardly projected deformity (38, 41, 44, 46) forms an acute angle.
7. An exhaust gas purification device as claimed in claim 4 and claim 5, characterized in that the height of the inwardly projected deformity (38, 41, 44, 46) is within the range of (17±5)% of the inner diameter of the tubular member.
8. An exhaust gas purification device as claimed in claim 4 and claim 5, characterized in that the inwardly projected deformities (38, 41, 44, 46) are formed in row at regular intervals in the axial direction of the tube of the tubular carrier (1, 37, 43, 45), and the distance between the inwardly projected deformities (38, 41, 44, 46) adjacent in the axial direction of the tube is 20mm to 30 mm, and a plurality of rows of the aforementioned rows are formed on a single tubular carrier (1, 37, 43, 45).
9. An exhaust gas purification device according to claim 1 to claim 8, characterized in that the tubular catalytic body is applied with catalyst only on the inner surface of the tubular carrier (1, 37, 43, 45).
-41 -

10. An exhaust gas purification device as claimed in claim 1 to claim 9,
characterized in that the tubular catalytic body of the exhaust gas

Documents:

646-mum-2002-abstract(24-01-2008).doc

646-mum-2002-abstract(24-01-2008).pdf

646-mum-2002-cancelled pages(24-01-2008).pdf

646-mum-2002-claims(granted)-(24-01-2008).doc

646-mum-2002-claims(granted)-(24-01-2008).pdf

646-mum-2002-correspondence(24-01-2008).pdf

646-mum-2002-correspondence(ipo)-(07-05-2007).pdf

646-mum-2002-drawing(29-07-2002).pdf

646-mum-2002-form 1(24-01-2008).pdf

646-mum-2002-form 13(24-01-2008).pdf

646-mum-2002-form 18(26-05-2006).pdf

646-mum-2002-form 2(granted)-(24-01-2008).doc

646-mum-2002-form 2(granted)-(24-01-2008).pdf

646-mum-2002-form 3(12-04-2004).pdf

646-mum-2002-form 3(16-07-2002).pdf

646-mum-2002-form 3(24-01-2008).pdf

646-mum-2002-form 5(16-07-2002).pdf

646-mum-2002-petition under rule 137(24-01-2008).pdf

646-mum-2002-petition under rule 138(24-01-2008).pdf

646-mum-2002-power of authority(16-02-2002).pdf

646-mum-2002-power of authority(24-01-2008).pdf

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Patent Number

214306

Indian Patent Application Number

646/MUM/2002

PG Journal Number

13/2008

Publication Date

28-Mar-2008

Grant Date

08-Feb-2008

Date of Filing

16-Jul-2002

Name of Patentee

HONDA GIKEN KOGYO KABUSHIKI KAISHA

Applicant Address

1-1, MINAMI-AOYAMA, 2-CHOME, MINATO-KU, TOKYO, JAPAN

Inventors:

#	Inventor's Name	Inventor's Address
1	HIROAKI MIYATA	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1, CHUO 1-CHOME, WAKOSHI, SAITAMA, JAPAN
2	HISAFUMI SHAKO	C/o. Kabushiki Kaisha Honda Gijutsu Kenkyusho, 4-1, chuo 1-chome, Wakoshi, Saitama
3	KOJI EGAWA	C/o. Kabushiki Kaisha Honda Gijutsu Kenkyusho, 4-1, chuo 1-chome, Wakoshi, Saitama

PCT International Classification Number

F01N3/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2001-240270	2001-08-08	Japan
2	2002-140195	2002-05-15	Japan