Muffler for small general-purpose engine

Abstract: A muffler for small general-purpose engine is disclosed, in which an interior of a case comprising a pair of case halves (2,3) and disposed from front to rear in an entering direction of an exhaust gas, and coupled together is divided into a first chamber (13) and a second chamber (14) by a partition plate (17). An inlet (7) of the exhaust gas is provided closer to one end portion of the first case half in the longitudinal direction. An outlet (10) of the exhaust gas is provided closer to the other end portion of the second case half in the longitudinal direction. A recess (18) project toward the second chamber for guiding the exhaust gas from the inlet toward the other end portion is provided in the partition plate at opposite location of the inlet and at a laterally offset location of the case. A communication orifice is formed in the partition plate at a location offset from the recess and also offset closer to the one end portion than the inlet.

Description: FIELD AND BACKGROUND OF THE INVENTION The present invention relates to a muffler for a small general-purpose engine, in which a noise reduction chamber is formed by a case having a pair of case halves coupled to each other through their flanges. A muffler for a small general-purpose engine is disclosed in Japanese Utility Model Publication No. S55-10580, in which a noise reduction chamber is formed by a case having a pair of case halves coupled to each other through their flanges, and directly secured to an engine. In this muffler, one of the case halves has an inlet for introducing the exhaust gas from the engine at the upper portion, and the other case half has an exhaust gas outlet at the lower portion. The case halves are coupled by seam welding their respective flanges to form the case. A vertically extending first guide member of a U-shaped cross section is provided in the case so that the exhaust gas introduced through the inlet is turned downward, and is turned upward by a vertically extending second guide member which is provided at downstream of the first guide member and having a U-shaped cross section. In such a muffler, the exhaust gas from the engine is guided downward by the first guide member immediately after the exhaust gas enters the muffler through the inlet in a direction substantially perpendicular to the direction in which it enters the case, and the exhaust gas is then guided upward by the second guide member. This structure causes a large flow resistance to the exhaust gas, restricting the flow of the exhaust gas and lowering the engine output. By curving the first guide member so that the exhaust gas entering the muffler is smoothly guided downward, this problem is avoided, but this has the drawback that the muffler is increased in size. Further, in such a muffler, it is difficult to sufficiently lower the noise level because the exhaust gas expands only once when it enters the upper noise reducing space in the case from the second exhaust gas passage in the second guide member. Further, the relatively complicated structure of the exhaust gas passage in the muffler, and seam welding for coupling two case halves, are disadvantageous in terms of cost for a muffler for a small general-purpose engine A muffler of more simple construction that is easier to manufacture than that described above is disclosed in Japanese Utility Model Publication No. H2-27129. More specifically, the interior of the case of the muffler is divided by a partition plate into two chambers, and the case is formed by coupling flanges of the pair of case halves by edge folding (a kind of caulking) sandwiching a partition plate therebetween to form a muffler of simple construction and for easy production while maintaining noise reduction. However, a necessity of improvement still remains as for a muffler for a small general-purpose engine, because the edge folding of the case halves and the partition plate for facilitating the production may cause a leakage of the exhaust gas which lowers noise reduction effect, and a seeping out of oil in the exhaust gas, depending upon the accuracy of coupling procedure. The muffler disclosed in the above-mentioned Japanese Utility Model Publication comprises a case comprising two case halves coupled to each other via their flanges; dividing means dividing the interior of the case into first and second chambers disposed one behind the other in the direction of entry of an exhaust gas into the case; an inlet for entry of the exhaust gas into the first chamber provided in the first case half at a location closer to a first end of the case than to the second end of the case in a longitudinal direction perpendicular to said direction of entry of the exhaust gas; and an outlet for discharging the exhaust gas provided in the second case half provided at a location closer to the second end of the case than to the first end of the case in the longitudinal direction. The partition has a recess opposite the inlet and axially aligned with the axis of the inlet. The partition is also provided with two rows of communication orifices extending across the majority of the width of the partition and located close to the second end of the case. In use the exhaust gas flows into the first chamber via the inlet, which is located close to the first end of the case, and flows along the length of the case to the second end from where it passes into the second chamber via the two rows of communication orifices. Once in the second chamber, the exhaust gas flows to an exhaust outlet, which is located closer to the first end than the second, but approximately midway along the length of the case. Thus the exhaust gas flows once along the majority of the length of the case in the first chamber and then once along less than half the length of the case in the second chamber. SUMMARY OF THE INVENTION The invention provides a muffler for a small general-purpose engine, said muffler comprising: a case comprising two case halves coupled to each other via their flanges; dividing means dividing the interior of the case into first and second chambers disposed one behind the other in the direction of entry of an exhaust gas into the case; an inlet for entry of the exhaust gas into the first chamber provided in the first case half at a location closer to a first end of the case than to the second end of the case in a longitudinal direction perpendicular to said direction of entry of the exhaust gas; and an outlet for discharging the exhaust gas provided in the second case half provided at a location closer to the second end of the case than to the first end of the case in the longitudinal direction; characterised by a recess in the dividing means opposite the inlet and offset in a lateral direction perpendicular to the direction of entry of the exhaust gas and the longitudinal direction of the case, said recess projecting towards the second chamber and, in use, receiving exhaust gas that enters the first chamber through the inlet and guiding the exhaust gas toward the second end of the case; and by at least one communication orifice provided in the dividing means at a location offset in said lateral direction with respect to the recess and closer to said first end than the inlet for passage of exhaust gas from said first chamber to said second chamber. Preferably, the recess is defined by a bottom wall which in the longitudinal direction towards the second end of the case is inclined toward the second chamber and a peripheral wall connected with the bottom wall that has a portion disposed closest to the second end of the case that in said longitudinal direction towards the second end of the case is inclined towards the first chamber. Preferably, the depth of the recess is larger than a depth of the portion of the first chamber defined by the first case half. Preferably, the periphery of the dividing means comprises a flattened bulge sandwiched between said flanges, one of said flanges has a bent portion at the free end thereof and the other said flange formed such that it covers the bulge and said bent portion to secure them under pressure whereby said bulge is flattened. Preferably, the outlet is disposed adjacent said second end of the case, whereby, in use, exhaust gas entering said second chamber through said at least one communication orifice has to travel from the region of said first end to the region of said second end to reach said outlet. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a right side view of a muffler according to an embodiment of the present invention mounted on an engine. Fig. 2(a) is an enlarged rear view of the muffler, and Fig. 2(b) is an enlarged front view of the muffler. Fig. 3 is an enlarged sectional view taken along the line III-III in Fig. 2(b). Fig. 4 is an enlarged sectional view taken along the line IV-IV in Fig. 2(a) Fig. 5(a) is a rear view of a partition plate of the muffler, and Fig. 5(b) is a sectional view taken along the line B-B in Fig. 5(a). Fig. 6(a) is an enlarged partial sectional view of a case before it is assembled, and Fig. 6(b) is an enlarged partial sectional view of the assembled case. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 1 shows a right side view of a muffler M according to the preferred embodiment of the present invention, in its mounted condition on an engine. A case 1, or outer shell, of the muffler M comprises a first case half 2 and a second case half 3 coupled to each other through flanges formed at outer peripheries thereof. Details of the coupling structure of the pair of case halves 2 and 3 will be described later. The muffler M is mounted on an engine E above a fuel tank T, at a location opposite to a carburetor C and an air cleaner K, by arranging the first and second case halves 2 and 3 in a forward-rearward (F-R) direction, and by screwing a bolt 4 inserted in the case 1 from the rear into a threaded hole of the engine E. Fig. 2(a) shows a front view of the muffler M as viewed from front F, and Fig. 2 (b) is a rear view of the muffler as viewed from rear R. The muffler M is longer in a longitudinal direction of the case 1 perpendicular to the entering direction of the exhaust gas G from the engine E. In this embodiment, the longitudinal direction coincides with a vertical direction of the muffler M. As shown in Fig. 2(a), an exhaust gas inlet flange 8 having an inlet 7 for exhaust gas from the engine E is formed at a position close to a first end, i.e., an upper portion of the forwardly arranged first case half 2, and as shown in Fig. 1, the muffler M is mounted to the engine E by connecting the exhaust gas inlet flange 8 to an exhaust flange E1 of the engine E. As shown in Fig. 2(b), a discharge pipe 9 for discharging the exhaust gas is mounted to the rearwardly arranged second case half 3, such that the discharge pipe 9 extends from about the central location of the portion close to the other, second, end, i.e. the central location of the portion of the lower end portion of the second case half 3 to the outside passing through a side wall of the second case half 3, and an exhaust gas outlet 10 is formed by the discharge pipe 9. A pair of insertion holes 11 and 12 for the bolts 4 are formed at the upper portion of the case halves 2 and 3 one on each side of the inlet 7 of the first case half 2. The muffler M is thus secured to the engine E by two bolts 4. Fig. 3 is an enlarged sectional view taken along the line III-III in Fig. 2(b), and Fig. 4 is an enlarged sectional view taken along the line IV-IV in Fig. 2(a). As shown in Fig. 3, an interior space of the case 1 is divided into a first chamber 13 and a second chamber 14 by dividing means in the form of a partition plate 17 interposed between the pair of case halves 2 and 3 from front to rear in the entering direction of the exhaust gas G from the engine E. Thus, the inlet 7 introduces the exhaust gas G from the engine E into an upper space in the first chamber 13, and the outlet 10 discharges the exhaust gas G passed through the case 1 from a lower portion of the second chamber 14. A recess 18 projecting toward the second chamber 14 is formed in the partition plate 17 opposite the inlet 7. An amount of projection (depth) "d" of a bottom surface 18a of the recess 18 toward the second chamber 14 is greater than the depth "e" the first chamber 13 of the first case half 2 in the forward-rearward (F-R) direction. In this embodiment, the bottom wall 18a of the recess 18 extends to the vicinity of a lath metal 24 provided on an inner side of the second case half 3 as will be described later. Further, the bottom wall 18a is inclined toward the second chamber 14 with respect to the direction toward the other end, i.e., slightly inclined rearward to the second chamber 14 with respect to the downward direction. A lower peripheral wall 18b of the recess 18 which is connected downwardly to the bottom wall 18a of the recess 18 in the partition plate 17 is inclined from the connected portion toward the opposite direction from the entering direction of the exhaust gas G with respect to the downward direction, i.e., inclined forwardly from the connected portion of the bottom wall 18a of the recess 18. As shown in Fig. 4, the recess 18 is provided at a position offset toward one of the lateral directions (leftward, in Fig. 4) perpendicular to both the direction of entry of the exhaust gas and the longitudinal direction. That is, one side peripheral wall 18c of the recess 18 is largely spaced apart from one side wall 3c of the second case half 3, and the other side peripheral wall 18d is located close to the other side wall 3d. An exhaust gas passage in the second chamber 14 is formed between the side peripheral wall 18c and the side wall 3c of the second case half 3, and the side peripheral walls 18c and 18d are formed as guide walls for guiding the exhaust gas downward in the first chamber 13. Fig. 5(a) is a rear view of the partition plate 17, and Fig. 5(b) is a sectional view taken along the line B-B in Fig. 5(a). As can be seen in Fig. 5(a), a plurality (four in the present embodiment) of communication orifices 20 are formed in the partition plate 17 at a location offset in one of the lateral directions (close to the side wall 3c) with respect to the recess 18, and located upward (close to the first end) of the inlet 7 (shown in two-dotted line in Fig. 5(a)) of the first case half 2, i.e., spaced upwardly and laterally with respect to the recess 18. Further, as shown in Fig 3, a lower projection 21 is formed in the partition 17 below the lower peripheral wall 18b. The lower projection 21 extends laterally and projects slightly toward the discharge pipe 9 in the second chamber 14. A pair of insertion holes 22, 22 are formed in the partition plate 17 at locations opposed to the insertion holes 11 and 12 of the case halves 2 and 3, through which a reinforcing pipe 23 is inserted for receiving a fastening force of the bolt 4 (Fig. 1) when the case 1 is mounted to the engine E. Each reinforcing pipe 23 is positioned so that its opposite opening ends coincide with the insertion holes 11 and 12 of the case halves 2 and 3, and is fastened and secured from both sides by the case halves 2 and 3. The bolt 4 shown in Fig. 1 is inserted through the reinforcing pipe 23 and screwed into the engine E. The mesh-like lath metals 24 are disposed on the inner sides of both case halves 2 and 3 at predetermined distances from inner surface of case halves 2 and 3, and peripheral portions of the lath metals 24 are secured to the inner surface of the case halves 2 and 3 by spot welding. Glass wool 27 fills the space between the case halves 2, 3 and the lath metals 24. The glass wool 27 has a noise reducing effect . A reinforcing plate 28 is fitted into the inner side of the inlet flange 8 and secured by the reinforcing pipe 23. As shown in Fig. 2(b), one end of the exhaust pipe 9 is inserted through and held at an opening 30 of a bearing hole in the second case half 3, and the exhaust pipe 9 is spot welded to a projection 29 (Fig. 3) formed in the lower portion of the second case half 3. A coupling structure of the case 1 will now be explained with reference to Fig. 6. As shown in Fig. 6(a), a swelled portion, or bulge, 31 projects forward F in an arc-shape. The bulge 31 is provided around the entire periphery of the partition plate 17. A bent portion 33 is formed to overlap along the entire length of the peripheral end of the flange 32 of the first case half 2 by bending the peripheral end in 180 degrees. When the case 1 is assembled, the swelled portion 31 of the partition plate 17 is interposed between the flanges 32 and 34 of the case halves 2 and 3, such that the swelled portion 31 of the partition plate 17 and the bent portion 33 of the first case half 2 are abutted against each other. Keeping this abutted state, the flange 34 of the second case half 3 is bent in a direction of the arrow P to enclose the swelled portion 31 and the bent portion 33, and the flange 34 is subjected to a caulking. By the caulking, a fastened portion 37 is formed on the flange 34 as shown in Fig. 6(b). The fastened portion 37 covers the expanded portion 31 and the bent portion 33 to press contact under pressure in the forward-rearward (F-R) direction, and both the case halves 2 and 3 as well as the partition plate 17 interposed therebetween are coupled integrally to form the case 1. In the case 1 constructed as described above, a firm connection is obtained, because the swelled portion 31 and the bent portion 33 are elastically deformed in the forward-rearward (F-R) direction so that the bent portion 33 and the swelled portion 31 are tightly contacted by a spring back forces which repulse to each other, when the fastened portion 37 is formed by caulking at the flange portion 34 of the second case half 3. Therefore, unlike connecting means, such as conventional edge-folding, connecting means this case 1 can be fabricated firmly by connecting the case halves 2, 3 and the partition plate 17 to each other under high sealing pressure, even when a flatness of each of the flanges 32 and 34 of the case halves 2 and 3 as well as the periphery of the partition plate 17 is insufficient. With this connection, leakage from the connected portion of flanges 32 and 34 is prevented, maintaining the noise reducing effect of the muffler at a high level. Further, seepage of oil in the exhaust gas is also prevented. Still further, the structure of the caulking portion is simple, because this structure is obtained by providing the swelled portion 31 with the partition plate 17, the bent portion 33 with one case half, and the fastening portion with the other case half for covering the swelled portion 31 and the bent portion 33. Operation of the muffler M will now be explained. The exhaust gas G from the engine E shown in Fig. 3 flows in the muffler through the following passages. As shown in arrows Figs. 2 to 4, the mainstream of the exhaust gas G from the engine is introduced in the first chamber 13 through the inlet 7 formed in the upper portion of the case 1, and flows within the first chamber 13 in a horizontal direction by inertia of the exhaust gas without changing the flowing direction into the recess 18 of the partition plate 17. Here, the projected amount "d" of the bottom wall 18a of the recess 18 toward the second chamber 14 is set longer than the depth (length in the F-R direction) "e" of first case half 2 which forms the first chamber 13, and the mainstream of the exhaust gas G flowing into the recess 18 flows downward without dispersing outside. Further, the impact speed of the exhaust gas G against the bottom wall 18a is moderated, because the projected amount "d" of the recess 18 is set as long as possible in the second case half 3, and the flowing direction of the exhaust gas G can be changed smoothly within the recess 18, The mainstream of the exhaust gas G in the recess 18 is guided downward smoothly without dispersing in lateral directions by the side peripheral walls 18c and 18d of the recess 18, and the bottom wall 18a of the recess 18 having a downward inclination toward the rearward direction R, and also by the lower peripheral wall 18b having a downward inclination toward the forward direction F. Because the communication orifices 20 are disposed at an upward and laterally offset location with respect to the recess 18, as shown in Fig. 5, the mainstream of the exhaust gas G introduced in the first chamber 13 through the inlet 7 is guided downward by the recess 18 as shown by arrows in Fig. 3 and only a small portion of the exhaust gas G in the recess 18 flows directly to the communication orifices 20. Arrows with two-dotted line in Fig. 2(a), indicate the flowing direction of the exhaust gas G from the inlet 7 to the communication orifices 20 by way of the recess 18 (Fig. 3). The mainstream of the exhaust gas G is guided downward by the side peripheral walls 18c and 18d of the recess 18 without dispersing laterally, and then flow into a narrow space of the front lower portion of the first chamber 13 surrounded by a lower portion of the first case half 2 and the lower projection 21 of the partition plate 17 as shown in Fig. 3, and the mainstream in the narrow space directly below the recess 18 is pushed laterally to the right direction as shown in Fig. 2(a), and changes its direction to flow upward toward the communication orifices 20, the only exit of the first chamber 13, and flows into the second chamber 14 through the communication orifices 20. In the second chamber 14, the mainstream flows downwards along the outside of the side peripheral wall 18c of the partition plate 17 projected into the second chamber 14 into the exhaust pipe 9, and is discharged from the outlet 10 of the exhaust pipe 9 as shown with arrows with dotted line in Fig. 2(a). As for the passages of the exhaust gas G within the case 1, because the interior of the case 1 is divided into the first chamber 13 and the second chamber 14 by the partition plate 17, as shown in Fig. 3, the exhaust gas G in the first chamber 13 is sufficiently throttled at the communication orifices 20 (Fig. 2(a)), and is expanded largely in the second chamber 14, sound pressure energy of the exhaust gas G is remarkably reduced. Further, the exhaust gas G introduced into the first chamber 13 is, at first, guided downward by the recess 18 into the lower portion of the case 1, and then changes its flowing direction upward to the upper portion, and flows into the second chamber 14 through the communication orifices 20, and again flows downward within the second chamber 14, and thus the exhaust gas G flows along a long passage effectively utilizing the entire space within the case 1. Therefore, the noise level due to the exhaust gas G can be effectively reduced, because the pressure of the exhaust gas G can be reduced effectively while it flows through the long passage. Further, in this muffler, the passage of the exhaust gas flowing downward to the lower end portion of the case 1 by the guidance of the recess 18 (Fig. 3), and the passage of the exhaust gas flowing upward from the lower end portion of the case 1 to the communication orifices 20 can be laterally juxtaposed within the same first chamber 13 as shown in Fig. 2(a), and therefore, although the flowing direction is reversed in the lower end of the first chamber 13, the exhaust gas G can flow smoothly. Still further, the structure of the muffler M is extremely simple, because the long passage for the exhaust gas in the muffler M is formed by dividing the interior of the case 1 by the partition plate 17 having the recess 18. When a power increase of the engine E is required, further communication orifices 20A shown in phantom lines in Fig. 5(a) may be provided at a lower portion of the inlet 7, in addition to the communication orifices 20 shown in solid lines. In the embodiment shown above, the exhaust gas G from the engine E is introduced from the inlet 7 near the upper end portion of the case 1. However, the same effect can be obtained by the structure that the exhaust gas G is introduced at the lower portion of the case 1 and is discharged at the upper portion of the case 1. In this case, the above described muffler M is vertically inverted. In the embodiment, when the first end of the case in the longitudinal direction is disposed uppermost, the exhaust gas from the engine flows in the muffler along the following paths. The exhaust gas enters the first chamber through the inlet formed in an upper end portion of the first case half, and flows straight across the first chamber by virtua of inertia of the exhaust gas and without changing direction into the opposed recess of the partition. The gas is guided downward along the recess into the lower portion of the first chamber. The exhaust gas in the lower portion of the first chamber is then pushed across the first chamber and the flow direction is reversed upward toward the communication orifices, which are located at upwardly and to one side of the recess. Then the exhaust gas flows into the second chamber through the communication orifices, and flows downward in the second chamber before being discharged from the outlet provided in the lower end portion of the second case half. Since the interior of the case is divided into the first and second chambers, the exhaust gas is sufficiently throttled, when the exhaust gas passes through the communication orifices from the first chamber, and expanded largely in the second chamber to reduce the sound pressure energy. Furthermore, the exhaust gas in the first chamber is guided downward by the recess and then is turned upward, and the exhaust gas flowing into the second chamber through the communication orifice is again guided downward to the outlet of the exhaust gas. The exhaust gas flows through this long passage effectively utilizing the entire inner space of the muffler, during which the pressure of the exhaust gas can be effectively lowered. Thus, the noise level due to the exhaust gas can be effectively lowered. The recess is provided at a laterally offset location with respect to the case and the inlet, and the communication orifice is provided at a laterally offset location with respect to the recess. Therefore, the paths of the exhaust gas flowing downward to the lower end portion of the case by the guidance of the recess and then upward from the lower end portion of the case toward the communication orifice are laterally juxtaposed in the same first chamber, effectively utilizing the interior space of the first chamber. Further, greater part of the mainstream of the exhaust gas flowing from the inlet to the recess is guided downward along the recess. The recess has a bottom wall which is inclined toward the second chamber with respect to the longitudinal direction of the case towards the second end portion of the case, and the portion of the peripheral wall of the recess closest to the second end is inclined from its connection to the bottom wall toward the first chamber. With this structure, the mainstream of the exhaust gas can be directed downward because the exhaust gas introduced in the recess from the inlet is smoothly guided downward along the bottom wall of the recess. The depth of the recess is greater than the depth of the portion of the first chamber defined by the first case half. With this structure, the mainstream of the exhaust gas introduced into the recess from the inlet smoothly flows downward without dispersion. The swelling portion, the bent portion, and the fastening portion are secured with each other under a high contacting pressure by a spring back force generated at the swelling portion and the bent portion when these portions are covered and deformed by the fastening portion. Therefore, a reliable halves or the periphery of the partition plate is insufficient. As a result, gas leakage from the flange is prevented, and a high noise reduction effect of the muffler is maintained. Numerous modifications and alternative embodiments of the present invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is for the purpose teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and/or function may be varied substantially within the scope of the appended claims.

Claims: A muffler for a small general-purpose engine, said muffler comprising: a case (1) comprising two case halves (2, 3) coupled to each other via their flanges (32, 34); dividing means (17) dividing the interior of the case into first and second chambers (13, 14) disposed one behind the other in the direction of entry of an exhaust gas into the case; an inlet (7) for entry of the exhaust gas into the first chamber provided in the first case half (2) at a location closer to a first end of the case than to a second end of the case in a longitudinal direction perpendicular to said direction of entry of the exhaust gas; and an outlet (9) for discharging the exhaust gas provided in the second case half (3) provided at a location closer to the second end of the case than to the first end of the case in the longitudinal direction; characterised by a recess (18) in the dividing means (17) opposite the inlet and offset in a lateral direction perpendicular to the direction of entry of the exhaust gas and the longitudinal direction of the case, said recess (18) projecting towards the second chamber (14) and, in use, receiving exhaust gas that enters the first chamber (13) through the inlet (7) and guiding the exhaust gas toward the second end of the case; and by at least one communication orifice (20) provided in the dividing means at a location offset in said lateral direction with respect to the recess (18) and closer to said first end than the inlet (7) for passage of exhaust gas from said first chamber to said second chamber. A muffler as claimed in claim 2, wherein the recess (18) is defined by a bottom wall (18a) which in the longitudinal direction towards the second end of the case is inclined toward the second chamber (14) and a peripheral wall connected with the bottom wall that has a portion (18b) disposed closest to the second end of the case that in said longitudinal direction towards the second end of the case is inclined towards the first chamber (13). A muffler as claimed in claim 1 or 2, wherein a depth (d) of the recess is larger than a depth (e) of the portion of the first chamber defined by the first case half (2). A muffler as claimed in claim 1, 2 or 3, wherein the periphery of the dividing means (17) comprises a flattened bulge (31) sandwiched between said flanges (32), one of said flanges (32) has a bent portion (33) at the free end thereof and the other said flange formed such that it covers the bulge and said bent portion to secure them under pressure whereby said bulge is flattened. A muffler as claimed in any one of the preceding claims, wherein said outlet (9) is disposed adjacent said second end of the case, whereby, in use, exhaust gas entering said second chamber (14) through said at least one communication orifice (20) has to travel from the region of said first end to the region of said second end to reach said outlet.

Inventors: TAKEMOTO KAZUHIKO, YAMANE YOSHIRO, YASHIRODAI TADAO, YUASA TSUNEYOSHI, TAKEMOTO, KAZUHIKO, YAMANE, YOSHIRO, YASHIRODAI, TADAO, YUASA, TSUNEYOSHI
Applicants: KAWASAKI HEAVY IND LTD, KAWASAKI JUKOGYO KABUSHIKI KAISHA
Application year: 1998
Main classification: F01N1
IPC codes: F01N1, F01N13