Patent Grant
8783024
This application is based on and claims Convention priority to Japanese patent application No. 2010-63672, filed Mar. 19, 2010, the entire disclosure of which is herein incorporated by reference as a part of this application.
1. Field of the Invention
The present invention relates to an exhaust chamber in the motorcycle exhaust system and, more particularly, to an exhaust chamber disposed on the motorcycle exhaust system at a location upstream of a muffler.
2. Description of the Related Art
The motorcycle exhaust system of a type having an exhaust control valve disposed at a location upstream of the muffler for adjusting the opening of the exhaust passage has been known. In this motorcycle exhaust system, it has been recognized that disposition of the exhaust control valve inside the muffler or the exhaust pipe is apt to impose a limitation on the freedom of design choice such as, for example, layout and/or material for the muffler or an exhaust pipe. To alleviate the limitation on the freedom of design choice, the Japanese Laid-open Patent Publication No. 2008-106644, first published May 8, 2008, discloses the use of an exhaust chamber, disposed upstream of the muffler and including communicating pipes communicated with a plurality of expansion compartments, and an exhaust control valve disposed within at least one of the communicating pipes for adjusting the sectional area of a passage inside such one of the communicating pipe.
However, according to the previously mentioned patent document, the exhaust control valve is disposed within the communicating passage inside the exhaust chamber, and, accordingly, the internal structure of the exhaust chamber tends to be complicated. In addition, the exhaust control valve employed require complicated maintenance and servicing works.
In view of the foregoing, the present invention has been devised to substantially alleviate the problems and inconveniences inherent in the prior art and is intended to provide an exhaust chamber in a motorcycle exhaust system, which has a simplified internal structure notwithstanding the use of the exhaust control valve within such exhaust chamber.
In order to accomplish the foregoing object, the present invention provides an exhaust chamber for a motorcycle disposed at a location upstream of a muffler in an exhaust passage leading from a combustion engine. The exhaust chamber includes a chamber body having an expansion compartment defined therein, a chamber outlet pipe having an outlet passage defined therein for discharging the exhaust gases from the chamber body, and an exhaust control valve disposed in the chamber outlet pipe for adjusting a sectional area of the outlet passage inside the chamber outlet pipe.
According to this construction, the use is made of the chamber outlet pipe having the exhaust control valve built therein and, therefore, the structure of the chamber body having the expansion compartment can be made simple to simplify the internal structure of the exhaust chamber, resulting in an increase of the assemblability of the exhaust chamber. Also, access to the exhaust control valve can be made easy and, therefore, the maintenance and servicing of the exhaust control valve can be facilitated.
In one preferred embodiment of the present invention, the exhaust chamber of the type referred to above preferably includes an chamber inlet pipe, which protrudes in an upstream direction from the chamber body for allowing the exhaust gases to flow therethrough into the chamber body; an introducing pipe having an introducing passage defined therein, which introducing pipe is disposed within the chamber body for introducing the exhaust gases, which have flowed through the chamber inlet pipe, into the chamber body; and a catalytic unit disposed within the introducing passage inside the introducing pipe for purifying the exhaust gases.
Disposition of the catalytic unit in the introducing pipe that is a member separate from the muffler allows the freedom of choice of the layout of and the material for the exhaust pipe and the muffler to expand. Also, since the exhaust control valve and the catalytic unit are integrated within the exhaust chamber, not only can the number of component parts used be reduced to suppress the cost, but also the motorcycle exhaust system can be laid out in a compact size. Moreover, since the catalytic unit is arranged at the inlet to the chamber body, the distance from the exhaust port of the combustion engine to the catalytic unit can be reduced to such an extent as to permit the temperature of the catalytic converter to be warmed up at the time the combustion engine is started, thus facilitating a quick activation of the catalyst in the catalytic converter.
In another preferred embodiment of the present invention, particularly where the exhaust chamber makes use of the catalytic unit as discussed above, the use may be made of a sensor fitted to the chamber inlet pipe for detecting a composition of the exhaust gases within the exhaust passage. The use of the exhaust gas sensor mounted on the chamber inlet pipe is effective to simplify the structure of the chamber body having the expansion compartment defined therein. Also, since in addition to the exhaust control valve and the catalytic unit, the exhaust gas sensor is as well integrated with the exhaust chamber, the number of component parts used can be further reduced and, therefore, reduction in cost and compactization of the motorcycle exhaust system can be accomplished advantageously.
In a further preferred embodiment of the present invention, particularly where the exhaust chamber makes use of the catalytic unit and the exhaust gas sensor as discussed above, the chamber inlet pipe may be positioned rearwardly downwardly of the combustion engine so as to extend in a direction longitudinally of the motorcycle and the sensor is fitted to the chamber inlet pipe so as to protrude diagonally upwardly and outwardly from the chamber inlet pipe. This is particularly advantageous that since the exhaust gas sensor protrudes diagonally upwardly and outwardly from the chamber inlet pipe, it is possible to avoid any undesirable interference of the sensor and a sensor cable with the combustion engine, the motorcycle frame structure and others and, also, the motorcycle bank angle can be earned.
In a still further preferred embodiment of the present invention, particularly where the exhaust chamber makes use of the catalytic unit as discussed above, the exhaust chamber may be made of the same material as a catalyst carrier accommodated inside the catalytic unit. The use of the material for the exhaust chamber, which is the same as that for the catalyst carrier, does in effect eliminate welding between dissimilar metals, and therefore, the welding quality can be increased.
In a still further preferred embodiment of the present invention, the chamber outlet pipe may be positioned at a location laterally of the motorcycle and between the combustion engine and a rear wheel so as to extend rearwardly and, also, the exhaust control valve may include a valve spindle, a valve operating member for driving the valve spindle, and a valve body mounted on the valve spindle for movement together therewith so as to form a butterfly valve, in which case the valve spindle is inclined in a direction inwardly of the motorcycle to allow the valve operating member to approach a center of the motorcycle. This design feature is particularly advantageous in that the possibility of the operating member for the exhaust control valve contacting a rider's foot can be avoided.
In a still further preferred embodiment of the present invention, a plurality of expansion compartments and a resonance compartment may be arranged inside the chamber body and the expansion compartment on the downstream end side or extreme downstream side with respect to the direction of flow of the exhaust gases and the resonance compartment are communicated with each other. This is particularly advantageous in that since the resonant frequency within the expansion compartment is lowered because of the temperature inside such expansion compartment being lower than that inside the expansion compartment on the upstream side, adjustment of the resonant frequency can be facilitated.
The present invention also provides a motorcycle equipped with the exhaust chamber of the type referred to above. The exhaust chamber mounted on the motorcycle includes a chamber inlet pipe for introducing exhaust gases into the chamber body, with the chamber body being positioned below the motorcycle and between the combustion engine and a rear wheel located rearwardly of the combustion engine. The chamber inlet pipe is positioned at a location substantially intermediate of a width of the motorcycle so as to protrude from the chamber body towards a space below the combustion engine while the chamber outlet pipe is positioned on one side of the motorcycle so as to protrude outwardly slantwise from the chamber body towards a space laterally of the rear wheel. With the motorcycle so designed as described above, an undesirable interference between the chamber inlet pipe and the combustion engine as well as between the chamber outlet pipe and the rear wheel can be advantageously avoided and, at the same time, the chamber body disposed between the combustion engine and the rear wheel can have a capacity as large as possible.
In any event, the present invention will become more clearly understood from the following description of preferred embodiments thereof, when taken in conjunction with the accompanying drawings. However, the embodiments and the drawings are given only for the purpose of illustration and explanation, and are not to be taken as limiting the scope of the present invention in any way whatsoever, which scope is to be determined by the appended claims. In the accompanying drawings, like reference numerals are used to denote like parts throughout the several views, and:
Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In particular,
A swingarm bracket 12 is secured to a rear end of the main frame assembly 1, which is situated at a lower intermediate portion of the motorcycle frame structure FR, and a swingarm 14 is pivotally connected to the swingarm bracket 12 for movement up and down, with a rear wheel 16 supported by this swingarm 14. A combustion engine E is fixedly mounted on that lower intermediate portion of the motorcycle frame structure FR and forwardly of the swingarm bracket 12 with respect to the direction of forward travel of the motorcycle so that the rear wheel 16 can be driven by the motorcycle engine E through a power transmitting member 17 such as a drive belt. The motorcycle engine E has a rear portion thereof having a transmission (not shown) built therein, and an oil pan 15 for accommodating a quantity of lubricant oil therein is positioned below the motorcycle engine E.
A motorcycle steering handlebar 19 is fixedly mounted on an upper end of the front fork 8. A fuel tank 20 is mounted on an upper portion of the main frame assembly 1 and a seat assembly including a driver's seat 22 and a rear fellow passenger's seat 24 is mounted on the rear frame assembly 2 in any manner well known to those skilled in the art. A rear footrest 26 for the fellow passenger is fixed to the rear frame assembly 2 through a footrest bracket 25. Also, a region of the motorcycle ranging from a top forward area of the front fork 8 to opposite side areas laterally of a front portion of the motorcycle body is covered by a fairing 27 made of a resinous material, with a rear portion of such fairing 27 covering opposite side portions and a lower portion of the motorcycle engine E.
The motorcycle engine E employed the instance as shown is in the form of a parallel four cylinder four-stroke engine and has four exhaust ports 28a defined at a front end portion of a cylinder head 28 of the engine E and four exhaust pipes 30 for guiding exhaust gases downwardly from a front area of the engine E are fluidly connected with those four exhaust ports 28a. Those four exhaust pipes 30 are merged together by a collecting duct 32 positioned beneath the engine E, and an exhaust chamber 34 is fluidly connected with a downstream end portion of the collecting duct 32. The exhaust chamber 34 is positioned between a bottom area of the engine E and the rear wheel 16, more specifically between the oil pan 15 beneath the engine E and the rear wheel 16 and generally below the swingarm bracket 12.
At a location rightwards of the motorcycle body with respect to the direction of forward travel of the motorcycle and downstream of the exhaust chamber 34, a muffler 36 made of a titanium or a titanium alloy (hereinafter, referred collectively to as a “titanium material”) is fluidly connected with the exhaust chamber 34. This muffler 36 has a mounting fixture 37 and is supported by one of the fellow passenger's footrest bracket 25 with the mounting fixture 37 secured to a mounting member 100 such as, for example, a bolt. Material for the muffler 36 may not necessarily be limited to the titanium material. The exhaust pipes 30, the collecting duct 32, the exhaust chamber 34 and the muffler 36 altogether forms a motorcycle exhaust passage 38.
As shown in a fragmentary bottom plan view in
The chamber body 40 has front and rear ends oriented forwards and rearwards of the motorcycle, respectively, with respect to the direction of forward travel of the motorcycle, and a right-hand portion of the forward end of the chamber body 40 as best shown in
The chamber inlet pipe 44 is positioned at a site substantially intermediate of the width of the motorcycle and extends in a direction conforming to the longitudinal direction of the motorcycle, terminating in fluid connection with a downstream end of the collecting duct 32. On the other hand, the chamber outlet pipe 46 extends in a direction laterally outwardly or rightwardly of the motorcycle and is fluidly connected with an upstream end of the muffler 36. The chamber body 40, the chamber inlet pipe 44 and the chamber outlet pipe 46 are all made of a metallic material such as, for example, the stainless material referred to previously.
As shown in an enlarged bottom plan view in
The chamber body 40 has its interior divided into a first expansion compartment 41, a second expansion compartment 42, a third expansion compartment 43 and a resonance compartment 48 by three partition walls 57A, 57B and 57C fitted inside inner surfaces of the casing structure 56. The first and second expansion compartments 41 and 42 are in communication with each other by means of a first communicating pipe 50, fitted to the first and second partition walls 57A and 57B, and the second and third expansion compartments 42 and 43 are in communication with each other by means of a second communicating pipe 52 fitted to the second partition wall 57B.
The chamber body 40 referred to above is formed integrally with a mounting lug 58 protruding outwardly from the front casing 56F and is supported by the swingarm bracket 12 by means of a set bolt 106 engaged in such mounting member 58.
The chamber inlet pipe 44 has a downstream end is opened to and communicated with the first expansion compartment 41 and the chamber outlet pipe 46 has an upstream end communicated with the third expansion to compartment 43. Also, the third expansion compartment 43 and the resonance compartment 48 are communicated with each other by means of a connecting pipe 54 fitted to the third partition wall 57C.
The partition walls 57A to 57C and the communicating pipes 50, 52 and 54 are all made of the stainless material, but they may not necessarily be limited thereto. Also, the number of the expansion compartments may not necessarily limited to three such as shown and described and the resonance compartment 48 may be dispensed with if so desired. In addition, though in this embodiment the resonance compartment 48 is communicated with the downstream end expansion compartment, the resonance compartment 48 may alternatively be communicated with an expansion compartment other than the downstream end compartment, that is, the upstream end expansion compartment or an intermediate expansion compartment intervening between the upstream and downstream end expansion compartments.
The first expansion chamber 41, best shown in
Referring to
The third expansion compartment 43 is positioned at a location rearwardly rightwards of the chamber body 40 and is adjoining the first expansion compartment 41, which is positioned on the front side thereof, through the first partition wall 57A, the second expansion compartment 42, which is positioned on the left side thereof, through the second partition wall 57B, and the resonance compartment 48, which is positioned on the front side thereof, through a right half of the third partition wall 57C. The second communicating pipe 52 extends through the second partition wall 57B so as to communicate the second expansion compartment 42 and the third expansion compartment 43 with each other.
The resonance compartment 48 is positioned forwardly leftwards of the chamber body 40 and is adjoining the first expansion chamber 41, which is positioned on the right side thereof, through the first partition wall 57A, and the second and third expansion compartments 42 and 43, both positioned on the rear side thereof, through left and right halves of the third partition wall 57C, respectively. The connecting pipe 54 extends through the right half of the third partition wall 57C so as to communicate the third expansion compartment 43 and the resonance compartment 48 with each other.
An introducing pipe 60 in the form of a pipe made of the stainless material is disposed inside the first expansion compartment 41. One end portion 60a of the introducing pipe 60 is fitted to an opening of the front casing 56F by means of a connecting means, for example, welding so as to be capped onto a downstream end 44a of the chamber inlet pipe 44, whereas the opposite end portion 60b thereof is left to open into the first expansion compartment 41. An introducing passage inside this introducing pipe 60 has a catalytic unit 64 disposed therein for substantially purifying the exhaust gases G.
As best shown in
As best shown in
A detection signal from the oxygen sensor 68 is fed to an engine controller (not shown) through a cable 70, and the engine controller controls the amount of a secondary air to be blown into the exhaust ports 28a (
Referring still to
As best shown in
The flow of the exhaust gases G emitted from the motorcycle engine E will now be described with particular reference to
The exhaust gases G within the chamber inlet pipe 44 are introduced into the chamber body 40 through the introducing pipe 60 shown in
Also, the third expansion compartment 43 on the downstream end side with respect to the direction of flow of the exhaust gases G is communicated with the resonance compartment 48 and, therefore, a portion of the exhaust gases G introduced into the third expansion compartment 43 flows into the resonance compartment 48 through the connecting pipe 54. At this time, since the first expansion compartment 41, in which the exhaust gases G of a relatively high temperature exist, adjoins the third expansion compartment 43 and the resonance compartment 48, in which the exhaust gases of a relatively low temperature exist, and since the first communicating pipe 50 extends across the interior of the third expansion compartment 43, heat exchange takes place across the partition plate 57A and a wall surface of the first communicating pipe 50 so that the high-temperature exhaust gases G having flowed through the catalytic unit 64 can be effectively cooled.
As hereinabove described, after the exhaust gases G have repeatedly expanded and constricted within the chamber body 40, the exhaust gases G are introduced from the exhaust chamber 34 into the muffler 36 through the chamber outlet pipe 46 and are then discharged to the atmosphere. At this time, by the selective opening or closure of the exhaust control valve 72 disposed inside the chamber outlet pipe 46, the flow of the exhaust gases G to be supplied to the muffler 36 can be adjusted.
According to the foregoing embodiment, since as best shown in
In addition, since the exhaust control valve 72 is disposed in the chamber outlet pipe 46, access to the exhaust control valve 72 can be made easy, compared with the structure in which the exhaust control valve is disposed interior of the chamber body, and therefore, maintenance and servicing of the exhaust control valve 72 can be facilitated. Also, since the exhaust control valve 72 is arranged downstream of the third expansion compartment 43 best shown in
Further, since the exhaust control valve 72 is employed as a member separate from any of the collecting duct 32 and the muffler 36 both best shown in
Also, considering that the catalytic unit 64 employed in the practice of the foregoing embodiment is disposed inside the exhaust chamber 34, the collecting duct 32 and the exhaust pipe 30 are no longer required to support the catalytic unit 64 and, therefore, they may not be made of a material that lends itself well to the support, for example, welding with the catalytic unit 64. Accordingly, the freedom of choice of material for the collecting duct 32 and the exhaust pipe 30 can be expanded.
Also, since the exhaust control valve 72, the catalytic unit 64 and the oxygen sensor 68 are all provided inside the exhaust chamber 34 to thereby integrate the exhaust chamber 34, not only can the number of component parts used and the cost be suppressed, but also the exhaust passage 38 (
Moreover, since the oxygen sensor 68 is so positioned as to protrude upwardly slantwise and outwardly as shown in
In addition, since the operating member 72b for driving the valve spindle 72a of the exhaust control valve 72 best shown in
Yet, as best shown in
Furthermore, as best shown in
Yet, since as shown in
Yet, when the catalytic unit 64 shown in
Also, since a major portion of a side wall of the chamber body 40 is left bare to the atmosphere without being covered by any of the fairing 27 and the exhaust cowling 76, the incoming wind can smoothly flow along the side wall of the exhaust chamber 34 and an excessive temperature rise of the chamber, which would result from the reaction of the catalyst, can be advantageously suppressed. In particular, when the right front end portion, which is a portion adjoining the catalytic unit 64 shown in
Furthermore, the introducing pipe 60 is fluidly connected with a front area of a widthwise right end portion of the chamber body 40 and a part of the wall of the first expansion compartment 41 is formed by a front portion of the right casing 56R. Since, as compared with any of widthwise intermediate and rear walls of the chamber body 40, the front area of the widthwise side wall of the chamber body 40 is apt to be cooled in contact with the incoming wind during the travel of the motorcycle, the possibility of the temperature of the first expansion compartment 41 becoming too high can be avoided. Also, since the front portion of the right casing 56R of the chamber body 40 is so formed as to smoothly bulge in a direction widthwise outwardly of the motorcycle towards the rear as viewed from bottom, the incoming wind can smoothly flow along the wall surface and, as a result, heat exchange occurs between the incoming wind and the wall surface enough to further suppress the undesirable temperature rise of the first expansion compartment 41.
Yet, as best shown in
The chamber cowling 49 employed in accordance with the second embodiment is prepared from a metal sheeting, made of the stainless material, by the use of any known bending technique and is fixed to the chamber body 40 by means of a connecting means such as, for example, welding. It is, however, to be noted that the material for and the method of fixing the chamber cowling 49 may not necessarily be limited to such as described above.
According to this second embodiment, since an outer side face of the chamber body 40 is covered by the chamber cowling 49, a major portion of the exhaust chamber 34A is not left bare to the outside and, accordingly, the appearance of the motorcycle can be improved. Also, as best shown in
Although according to the second embodiment described hereinabove, the chamber cowling 49A has been shown and described as employed on the right side of the exhaust chamber 34, it may be employed on opposite sides of the exhaust chamber 34A. Also, although the chamber cowling 49 has been described as formed by fixing a metal sheeting, which has been bent, to the exhaust chamber 34A, the present invention may not necessarily be limited thereto. By way of example, the fairing 27 shown in
Also, the chamber cowling 49 may be fixed to the chamber body 40 with no gap or opening left in an edge portion over the entire perimeter thereof. By so doing, a sealed air layer can be formed between the chamber body 40 and the atmosphere and, therefore, even when the ambient temperature is relatively low, the interior of the chamber body 40 can be quickly warmed up to allow the catalyst to be quickly activated.
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings which are used only for the purpose of illustration, those skilled in the art will readily conceive numerous changes and modifications within the framework of obviousness upon the reading of the specification herein presented of the present invention. By way of example, although in any one of the foregoing embodiments of the present invention, the oxygen sensor 68 and the catalytic unit 64 have been shown and described as provided in the chamber inlet pipe 44 and the introducing pipe 60, respectively, the oxygen sensor 68 and the catalytic unit 64 may be fixed in one and the same pipe.
Also, a portion of the rear end wall of the chamber body 40 adjacent the rear wheel 16 may be provided with a heat insulating plate for avoiding transmission of heat to the rear wheel 16.
Accordingly, such changes and modifications are, unless they depart from the scope of the present invention as delivered from the claims annexed hereto, to be construed as included therein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-063672 | Mar 2010 | JP | national |
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| Entry |
|---|
| Japanese Application No. 2010-063672 Office Action dated Sep. 3, 2013, 6 pages with partial English translation. |
| Number | Date | Country | |
|---|---|---|---|
| 20110225953 A1 | Sep 2011 | US |
