Title of Invention

"AN INTAKE ASSEMBLY OF AN INTERNAL COMBUSTION ENGINE"

Abstract

To provide an intake assembly of an internal combustion engine, offering large freedom lor installation of an intake chamber, and being capable of avoiding interference with a vehicle body, without unnecessariy lengthening a fuel/air mixture outlet/inlet branching pipe. [Solution means] in an intake assembly of an internal combustion engine in which a fuel/air mixture outlet/inlet branching pipe 22d is branched from an intake pipe 22a on the downstream side of a throttle valve, and an intake chamber 30 is connected to the branching pipe 22d, the :ntake chamber 30 is provided to an air cleaner case 26 to be connected on the upstream side of the throttle valve.

Full Text

Brief description of the invention Field of the invention The present invention relates to an intake assembly of an internal combustion engine. The present invention relates to an intake system having an intake chamber of an internal combustion engine. [ Prior art] There has been conventionally proposed an intake system which achieves increased intake efficiency by smoothing an intake flow, wherein an intake chamber is connected to a branching pipe branched from an intake path on the downstream side of a throttle valve. An intake flow is smoothed by introducing a fuel/air mixture into an intake chamber by utilizing pressure variations in the intake path, and driving out the fuel/air mixture introduced into the intake chamber into a cylinder after having air join the fuel/air mixture flowing in the intake path. Japanese Utility Model Laid-Open Publication No. Hei 3-51162 discloses an example in which an intake chamber is installed to the swing unit of a motorcycle having a unit swing internal combustion engine. In this example, a two-cycle internal combustion engine is provided in front of the swing unit, and an intake pipe extends from a carburetor side intake hole formed on the crank case of the engine, to be connected to a carburetor. A fuel/air mixture outlet/inlet branching pipe is branched from the intake pipe, extending upward to be connected to the intake chamber. The intake chamber is fixed by means of a rivet to a shroud which covers a cylinder protruding from the crank case. [Problems to be solved by the invention] Since the fuel/air mixture outlet/inlet branching pipe is branched from the intake pipe, the intake chamber connected to the fuel/air mixture outlet/inlet branching pipe is installed on the side surface of the shroud where the intake pipe extends. This reduced freedom in installing an intake chamber. Further, it" an intake chamber is installed on the other side surface of the shroud, an unnecessarily long pipe is required, and a problem of interference with other members will occur. With a unit swing internal combustion engine, since an internal combustion engine is installed close lo the center of swing, enough room cannot be ensured between the shroud covering the cylinder of the internal combustion engine and the vehicle body above the shroud. Thus, an intake chamber installed attached to the shroud cannot secure enough capacity. In order to ensure that an intake chamber has a capacity in excess of an exhaustion amount, the intake chamber having this capacity is therefore positioned above the fuel/air mixture outlet/inlet branching pipe branched upward from the intake pipe. The highest position of the intake chamber is located still higher than the shroud as a result, which causes a problem of interference between the intake chamber which swings accompanying the swing unit, and the vehicle body above the chamber. The present invention has been conceived to solve the above problems, and aims to provide an intake assembly for an internal combustion engine which brings about a large degree of freedom with regards to installation of an intake chamber, and avoids interference with a vehicle, without unnecessarily lengthening a fuel/air mixture outlet/inlet branching pipe. [ Means to solve the problem and advantages in operation] In order to solve the problem, according to the present invention, there is provided an .intake assembly of an internal combustion assembly in which a fuel/air mixture outlet/inlet branching pipe is branched from an intake path on a downstream side of a throttle valve, and an intake chamber is connected to the branching pipe, wherein the intake chamber is provided to an air cleaner connected on an upstream side of the throttle valve. Since the fuel/air mixture outlet/inlet branching pipe is branched from an intake path on the downstream side of a throttle valve, and connected to an intake chamber provided on an air cleaner case on the upstream side of the throttle valve, a short pipe can be used, when arranged so as to detour around the throttle valve. Moreover, a large space can be secured where the chamber is attached to the an air cleaner case, leaving a large degree of freedom for installation. Also, even in applications to unit swing internal combustion engines, since the air cleaner case is arranged at a distance from the center of swing, enough room can be secured between the air cleaner case and the vehicle, and interference between an intake chamber installed to the air cleaner case and the vehicle body can be easily avoided. According to the invention of claim 2, in an intake assembly of an internal combustion assembly according to claim 1, the intake chamber is provided so as to be overlapped by the air cleaner case when viewed from the side. The intake chamber can be provided without protruding higher than the air cleaner case, which is further effective in avoiding interference with a vehicle. Also, the intake chamber can be hidden by the air cleaner case, and a better appearance can be thus presented. According to the invention of claim 3, in an intake assembly of an internal combustion assembly according to claim 1. the intake chamber is provided above the air cleaner case. As larger freedom can be ensured for installation of the intake chamber to the air cleaner case, it is possible to install the intake chamber also above the air cleaner case, while using a short fuel/air mixture outlet/inlet branching pipe and avoiding interference with the vehicle body. According to the invention of claim 4, in an intake assembly of an internal combustion assembly according to any one of claims 1 to 3, the intake chamber and the air cleaner case are separately formed. Since the intake chamber is provided to a highly rigid air cleaner, it can be securely fixed. Maintenance solely for the intake chamber can be conducted easily, and intake chambers can be exchanged. According to the invention of claim 5, in an intake assembly of an internal combustion assembly according to any one of claims 1 to 3, the intake chamber is formed integrally with the air cleaner case. The number of parts is reduced, thereby simplifying an assembly operation. According to the invention of claim 6, in an intake assembly of an internal combustion assembly according to any one of claims 1 to 5, the internal combustion assembly is a unit swing internal combustion engine, and the air cleaner is provided above a swing unit. In a unit swing internal combustion engine, an intake chamber can be provided to an air cleaner. Accordingly the present invention relates to an intake assembly of an internal combustion engine with a fuel/air mixture outlet/inlet branching pipe branching from an intake path on a downstream side of a throttle valve, and an intake chamber being connected to the branching pipe, charactered in that the intake chamber is provided to an air cleaner connected on an upstream side of throttle valve the internal combustion assembly is a unit swing internal combustion engine, and the air cleaner is provided above a swing unit. (Brief description of the drawings] A entire side view of a motorcycle according to a preferred embodiment of the present invention. A side view showing a suing unit with a part broken away. [Fig. 3] A plan view showing a swing unit with a part broken away. [Fig. 4] A side view showing a shroud. [Fig- 5] A plan view showing a shroud. [Fig. 6] A side view showing an intake pipe member. [Fig. 7] A plan view showing an intake pipe member. [Fig- 8] A rear view showing an intake pipe member. [Fig. 9] A left side view showing an air cleaner case. [Fig. 10] A plan view showing an air cleaner case. [Fig. 11] A cross sectional view along the line XI-XI in Fig. 9. [Fig. 12] A side view showing an intake chamber. [Fig. 13] A plan view showing an intake chamber. [Fig. 14] A front view showing an intake chamber. [Fig. 15] A cross sectional view along the line XV-XV in Fig. 3. [Fig. 16] A side view showing a swing unit according to another preferred embodiment with a part broken away. [Fig. 17] A plan view showing a swing unit of Fig. 16. [Fig. 18] A side view of an intake chamber. [Fig. 19] A bottom view of an intake .chamber. [Preferred embodiment of the present invention] In the following, a preferred embodiment of the present invention will be described referring to Figs. 1 to 15. In this embodiment, the present invention is applied to a motorcycle 1 having a unit swing internal combustion engine. Fig. 1 is a side view of the motorcycle 1. A vehicle front section 2 and vehicle rear section 3 are connected via a low step section 4. A vehicle frame, constituting a framework of the vehicle, comprises a front frame 5a which descends on the vehicle front section, a pair of left and right rear horizontal frames 5b separated into two parts at the lower end of the front frame 5a and extending backward under the step section 4. and a pair of left and right rear frames 5c standing diagonally upward in the rear direction from the respective rear parts of the horizontal frames 5b. A seat 6 is mounted above the rear frame 5c of the vehicle rear section 3, and a storage box 7 is installed below the seat 6. In the vehicle front section 2, a steering head 9 having a handle 8 is attached to the upper part thereof, while a front wheel 1 1 is suspended via a front fork 10 in the lower part thereof, so that the front wheel 1 1 is steered by the handle 8. The front end of a swing unit 15 is connected via a link member 12 to the curving section in the rear part of the horizontal frame 5b. The swing unit 15 is connected via the link member 12 to the vehicle frame 5 so as to be horizontally movable. A rear cushion 13 is provided between the rear part of the swing unit 15 and the rear frame 5c above thereof. On the swing unit 15. the front part of a horizontally longitudinal belt control case 20 serves as a crank case, and internal combustion engine 16 is provided on the entire swing unit 15. A rear wheel 1 8 is suspended at the rear part of the case 20, which serves as a transmission case. The driving forces generated by the internal combustion engine 16 are transmitted via a belt controller 1 7. or a belt transmission mechanism having an automatic speed changing function, to the rear wheel 1 8. Note that a hanger bracket 10 protrudes from the front end of the belt control case 20 and is connected to the link member 12. An opening on the left side of the belt control case 20 is covered by a transmission case cover 28. The internal combustion engine 16 is a two-cycle internal combustion engine, in which a cylinder 16a covered by the shroud 19 stands slightly backward. An intake opening 21 is formed on the upper surface of the crank case left of the cylinder 16a. A lead valve if fitted into an intake port on the downstream side of the intake opening 21. The intake opening 2 1 receives an intake pipe member 22, whose intake pipe 22b extends leftward and bonds backward to be connected to a carburetor 23. The carburetor 23 is in turn connected via a connection pipe 24 to an air cleaner 25 provided above the rear half of the belt control case 20. The shroud 19 covering the cylinder 16a, as shown in Figs. 4 and 5, comprises mainly a side wall 19a and an upper wall 19b in the form of a rectangular cylinder. An extension part 19c extends backwards from the left rear edge of the side wall 19a. A round opening 19d is formed on the upper wall 19b, corresponding to the axial center of the cylinder. A substantially rectangular deficient part 19e is formed on the lower part of the left side wall 19a. A swelling part 19f swelling leftward is formed above the deficient part 19e. An exhaust port 1 l)g is formed above the swelling part 19f, facing backward and leftward. With the shroud 19 covering the cylinder 16a, the intake opening 21 on the upper surface of the crank case and the right half of the intake pipe member 22 connected to the intake opening 21 are resultantly positioned inside the shroud 19, while the left half of the intake pipe member 22 extends through the deficient part 19e of the shroud 19. With the intake pipe member 22, as shown in Figs. 6 to 8, an intake pipe 22b extends diagonally upward in the left direction from the center of a substantially rectangular connection base 22a to be attached to the intake opening 22, with the tip end of the intake pipe 22b bending backward thereby constituting a connection part 22c. A connection branching pipe 22d for an intake chamber is formed integrally with the intake pipe 22b. branched from a part of the pipe 22b extending from the connection base 22a. Further, a connection branching pipe 22e for an auto cock projects from a part of the intake pipe 22h before the connection section 22c. The fuel/air mixture outlet connection section 23b of the carburetor 23 is connected to the connection pan 22c which is an upstream part of the intake pipe 22b. The carburetor 23 connected to the intake pipe member 22 has a motorcycle starter 23a, in which the fuel/air mixture outlet connection section 23b facing frontward is connected to the connection part 22c on the upstream side of the intake pipe 22b, while the air intake connection part 23c facing backward is connected to the air cleaner 25 via the connection pipe 24. The air cleaner 25 comprises an air cleaner case 26 and a case cover 27 covering the left side of the opening of the air cleaner 25. In the air cleaner case 26. as shown in Figs. 9 to 11, a recess which swells from the opening peripheral edge pan on the left side thereof to the right side thereof is vertically divided at a part closer to the rear end by a wall 26b, into a rectangular recess 26c on the front side and an outside air intake recess 26d on the rear side. In the front half of the rectangular recess 26c on the front side, a trapezoid recess 26e is formed, which is indented towards the right. In the outside air intake recess 26d on the rear side, a rectangular pipe 26f is formed projecting diagonally upwards, with the upper end thereof communicating with the inside and the lower end thereof being open to the outside. With the trapezoid recess 26e in the front half of the rectangular recess 26c, the right side of the upper wall is made to be concave thereby forming a step part 26g. Further, the horizontal wall of the step part 26g is partially recessed in a rectangular shape, thereby forming a recess 26h. A screw hole 26i is formed on the vertical wall of the recess 26h. On the front wall of the trapezoid recess 26e, a round opening 26j is formed to communicate with the connection pipe 24. Brackets 26k. 261 protrude from the lower walls of the rectangular recess 26c and the trapezoid recess 26d for attachment to the belt control case 20. The case cover 27 covers the left side of the air cleaner case so as to cover the opening of the air cleaner case 26. and extends from the air cleaner case 26 further frontward to cover the left side of the carburetor 23 (see Fig. 3). The intake chamber 30 is attached to the step part 26g of the air cleaner case 26. The intake chamber 30 is. as shown in Figs. 12 to 14, of a cylinder which is long in the front and rear direction, having a connection pipe 30a protruding from the lower part of the front wall. An installation piece 30b protrudes downward from the bottom wall of the intake chamber 20. An installation hole 20c is formed at the center of the piece 30b. When the intake chamber 30 is fitted into the step part 27g of the air cleaner case 26 so as to have a predetermined positional relationship, the piece 30b is fitted into the recess 26h. Referring to Fig. 15. a screw 32 therefore pierces the installation hole 30c of the piece 30b so as to be threaded in. so that the intake chamber can be fixed to the air cleaner case 26. As shown in Fig. 15. the intake chamber 30 installed to the air cleaner case 26 is positioned such that the highest part thereof is of substantially the same height as the air cleaner case 26. The intake chamber 30 therefore cannot be seen from the outside due to being hidden by the air cleaner 25. so that a better appearance is presented. The intake chamber 30 installed to the air cleaner case 26 as described above is positioned on the rear side of the connection branching pipe 22d branched upward from the intake pipe 22b of the intake pipe member 22, as shown in Fig. 3, and the connection pipe 30a of the intake chamber 30 protrudes toward the connection branching pipe 22d. The connection branching pipe 22d and the connection pipe 30 which are positioned close to each other, are connected via an intake hose 3 1 . constituting the fuel/air mixture outlet/inlet branching pipe. With the shroud 19 covering the cylinder 16a of the internal combustion engine 16, the swelling part 19f of the shroud 19. which swells leftward, covers the connection branching pipe 29d branched upward from the intake pipe 22b. and the exhaust opening 9g formed on the upper part of the swelling part 19f faces in the back and left directions, i.e., toward the carburetor 23 and the intake chamber 30. Therefore, warm air discharged from the exhaust port 19g blows into and thus warms the carburetor 23. so that icing can be prevented. In particular, as shown in Fig. 3, since the extension part 19c of the shroud 19 constitutes a wall on the right side of the carburetor 23, and the left outside of the carburetor 23 is covered by the extension part of the case cover 27, the discharged air effectively affects the carburetor 23, largely contributing to an icing prevention effect. Also, the intake hose 31 whose rear end is connected to the connection pipe 30a of the intake chamber 20. extends frontward, being introduced into inside the shroud 19 through the exhaust port 1 9g formed on the shroud 19 facing backward. The front end of the intake hose 31 is connected to the connection branching pipe 22d branched upward from the intake pipe 22b. With this arrangement, the intake pipe 22b communicates with the intake chamber 30. Since the intake hose 3 1 passes through the exhaust port 19g of the shroud 19, there is no need to provide an opening on the shroud 19 for the intake hose 31. As described above, the intake hose 31 has the connection branching pipe 22d branched upward from the intake pipe 22b on the downstream side of the throttle valve inside the carburetor 23 to communicate with the connection pipe 30a protruding forward from the intake chamber 30 installed to the step part 26g of the air cleaner case 26 on the upstream side of the throttle valve. Since the connection branching pipe 22d and the connection pipe 30a, positioned close to each other on the right side of the carburetor 23, communicate with each other, a short hose can be used for the intake hose 3 1 without causing any inconvenience in terms of charging capability and lay-out. The air cleaner case 26 to which the intake chamber 30 is attached is positioned away from the link member 12. which is the swing center of the swing unit 15, leaving sufficient room for the above vehicle body. At the same time, the intake chamber 30, attached to the step part 26g of the air cleaner case 26. does not project above the air cleaner 25, and thus does not interfere with the vehicle body even though it swings together with the swing unit 15. The intake chamber 30 installed as above communicates with the branching part of the intake pipe 22b via the intake hose 31, wherein the branching part is positioned at the middle between the throttle valve on the upstream side and the lead valve on the downstream side. Therefore, it is possible to increase air intake efficiency by introducing the floating fuel/air mixture into the intake chamber 30 when the lead valve is closed, and by taking in the fuel/air mixture after having the fuel/air mixture join the fuel/air mixture floating inside the intake pipe 22b when the lead valve is open. The installation place for the intake chamber 30 is not limited to on the step part 26g, and the chamber 30 may be attached to another part of the air cleaner case 26 without using a very long intake hose 31. The intake chamber 30 has a large degree of freedom with respect to installation. In the next preferred embodiment, as shown in Figs. 16 and 17, the intake chamber 50 is installed above the air cleaner case 61. .(0047] The intake chamber 50. as shown in Fig. 18 and 19, is shorter in the front and rear direction than the intake chamber 30. and has a connection pipe 50 protruding frontward from the lower part of the front wall thereof, and an installation piece 50b protruding from the lower surface of the bottom wall. The installation piece 50b is long in the front and rear direction, having an installation hole 50c formed on the rear part thereof. An engaging tip 50d protrudes from the front end of the installation piece 50b. On the other hand, a screw hole boss part 61a is formed on the left side on the upper surface of the nir cleaner case, at a part closer to the front. An engaging recess part 61 b is formed in front of the screw hole boss part 61a. The engaging tip 50 is inserted into and engaged with the engaging recess part 61b at a predetermined position on the upper surface of the air cleaner case 61. The installation piece 50b is abutted on the screw hole boss part 61a from the right side so that a screw 62 pierces the installation hole so as to thread into the screw hole boss section 16a, so that the intake chamber 50 is fixed onto the air cleaner case 61 . As described above, one end of the intake hose 51 is connected to the connection pipe 50a which extends frontward from the intake chamber 50 installed above the air cleaner case 61. The connection hose 51 extends frontward from the connection pipe 50a, and bends from the left side to the front side of the carburetor 63. with the other end being connected to the connection branching pipe 64a branched from the intake pipe 64 on the downstream side the carburetor 63. The intake hose 51 is not very long. Although the intake chamber 50 is installed above the upper part of the air cleaner 60 in this embodiment, it is positioned away from the swing center of the swing unit, leaving sufficient room to the above vehicle body, and the intake chamber 50 thus does not interfere with the vehicle body. Since the intake chamber 50 is provided so as to be exposed to the outside, maintenance or exchange of the intake chamber 50 only can be easily achieved. Although the intake chamber and an air cleaner are separate bodies and attached together via a screw in the above embodiment, they may be formed as an integrated body in advance. The number of parts can be reduced, and an assembly operation can be easily conducted. We Claim: 1. An intake assembly of an internal combustion engine with a fuel/air mixture outlet/inlet branching pipe (31, 51) branching from an intake path (22, 64) on a downstream side of a throttle valve (23), and an intake chamber (30, 50) being connected to the branching pipe, chareuteryed in that the intake chamber (30, 50) is provided to an air cleaner (25, 60) connected on an upstream side of throttle valve (23) the internal combustion assembly is a unit swing internal combustion engine, and the air cleaner is provided above a swing unit (15). 2. An intake assembly of an internal combustion engine as claimed in claim 1, wherein the intake chamber is provided above the air cleaner case; wherein the intake chamber is provided so as to be overlapped by the air cleaner case in a side. 3. An intake assembly of an internal combustion engine as claimed in any one of claims 1 or 2, wherein the intake chamber and the air cleaner case are formed separately. 4. An intake assembly of an internal combustion engine as claimed in any one of claims 1 or 2, wherein the intake chamber is formed integrally with the air cleaner case. 5. An intake assembly of internal combustion engine substantially as herein described with reference to the accompanying drawings.

Documents:

782-del-1998-abstract.pdf

782-del-1998-claims.pdf

782-del-1998-correspondence-others.pdf

782-del-1998-correspondence-po.pdf

782-del-1998-description (complete).pdf

782-del-1998-drawings.pdf

782-del-1998-form-1.pdf

782-del-1998-form-13.pdf

782-del-1998-form-19.pdf

782-del-1998-form-2.pdf

782-del-1998-form-3.pdf

782-del-1998-form-4.pdf

782-del-1998-form-6.pdf

782-del-1998-gpa.pdf

782-del-1998-petition-137.pdf

782-del-1998-petition-138.pdf

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