JP6523027B2 - Intake device for an internal combustion engine for a small vehicle - Google Patents

Description

  The present invention is a fuel supply means for mixing fuel with intake air in the middle of an intake passage in which the downstream end is in communication with the intake port of the engine body mounted on the vehicle body frame and the upstream end is in communication with the clean chamber of the air cleaner. The present invention relates to an intake system for an internal combustion engine for a small vehicle, in which

  In an internal combustion engine mounted on a motorcycle which is a small vehicle, a cylinder head which is a part of an engine body is connected to a carburetor which is a fuel supply means via an intake pipe connected to an intake port, and connected to this carburetor Patent Document 1 discloses an air cleaner connected via a tube, in which a connecting portion of the connecting tube to the air cleaner is provided at an intermediate portion in the vertical direction of the air cleaner, and an air cleaner is connected to the air cleaner from the intake port. Up to the intake passage is generally horizontal.

JP 2000-53055 A

  By the way, in a small vehicle which can not secure a long distance between the fuel supply means such as a carburetor and the air cleaner, the air-fuel mixture mixed with air in the intake passage is returned to the air cleaner by the blowback gas in the intake passage. As a result, fuel may stay in the air cleaner. In this case, when the intake passage extends substantially horizontally as disclosed in Patent Document 1 described above, it is difficult for the fuel accumulated in the air cleaner to be discharged, and a connection port connected to the intake passage is provided at the middle portion in the vertical direction of the air cleaner. Therefore, fuel does not accumulate at the bottom of the air cleaner and is not discharged. Therefore, a drain hole for fuel is provided at the bottom of the cleaner case for discharging the fuel from the inside of the air cleaner, and the fuel discharged from the drain hole and accumulated in the fuel reservoir is periodically discharged or cleaned. Although it is necessary to carry out maintenance work, it is desirable that maintenance-free operation be achieved, if possible, since discharge of fuel accumulated in the air cleaner and cleaning thereof are unnecessary.

  The present invention has been made in view of such circumstances, and provides an intake system for an internal combustion engine for a small vehicle that prevents fuel from being accumulated in the air cleaner and does not require maintenance for discharging the fuel from the air cleaner. The purpose is to

  In order to achieve the above object, according to the present invention, the intake air is connected to an intake passage whose downstream end is in communication with the intake port of the engine body mounted on the vehicle body frame and whose upstream end is in communication with the clean chamber of the air cleaner. In an intake system of an internal combustion engine for a small vehicle, in which a fuel supply unit for mixing fuel is interposed, the air cleaner is disposed at a position separated in the front-rear direction from the fuel supply unit in a vehicle mounted state. The bottom wall of the clean chamber formed in the inside is inclined to be gradually lowered toward one side in the vehicle width direction, and the lowest portion of the bottom wall is directed from the intake port toward the air cleaner side According to a first feature of the present invention, there is provided a connection port which allows the upstream end of the intake passage to gradually come to an upper position.

  Further, according to the present invention, in addition to the configuration of the first feature, a connection cylinder which is continuous with the connection port and protrudes outward from the cleaner case is integrally formed on the cleaner case, and an upstream end of the intake passage According to a second feature of the present invention, an upstream end of an intake pipe member forming the first and second connecting members is connected to the connecting cylinder.

  According to the present invention, in addition to the configuration of the second feature, the vehicle body frame includes a frame member inclined rearwardly and downwardly through the air cleaner, and at least a part of the bottom wall of the clean chamber According to a third feature of the present invention, an inclined wall portion is formed in front of the connection port so as to be along the frame member, and the connection port is provided at the lowest portion of the inclined wall portion.

  According to the present invention, in addition to any one of the configurations of the first to third features, a gas-liquid separation chamber for introducing a breather gas from the engine body to perform gas-liquid separation is disposed rearward of the connection port. To form in the clean chamber in a manner as described above.

  According to the present invention, in addition to the configuration of the fourth feature, the air cleaner forms a clean side case forming a part of the clean chamber, and forms a part of a dirty chamber to form the cleaner case together with the clean side case. The apparatus comprises: a dirty side case to be configured; and a partition wall which holds the cleaner element and is partitioned between the clean chamber and the dirty chamber to be sandwiched between the clean side case and the dirty side case; the bottom of the clean chamber A separation wall forming a recess opening to the partition wall side between the wall and the wall is integrally provided in the clean side case, the gas-liquid separation chamber includes the bottom wall and the separation wall of the clean chamber, and A fifth feature is that the partition wall is formed by the partition wall adjacent to and facing the open end of the recess.

  According to a sixth feature of the present invention, in addition to the configuration of the fifth feature, the partition wall is integrally provided with a rib extending along the separation wall in the gas-liquid separation chamber.

  According to the present invention, in addition to any of the configurations of the first to sixth features, the cleaner case forms a clean side case forming a part of the clean chamber, and a part of a dirty chamber to form the clean The bottom wall of the dirty side case, which comprises the dirty side case coupled to the side case, and which forms the bottom of the dirty chamber, is formed to be inclined downward as it approaches the clean side case, A portion of the bottom wall of the dirty side case closer to the clean side case is provided with a drain hole for draining water in the dirty chamber, and a ridge covering the drain hole from above is integrated with the dirty side case. A seventh feature is to be provided.

  Furthermore, according to the present invention, in addition to the configuration of the seventh feature, a partition wall partitioning between the clean chamber and the dirty chamber while holding the cleaner element is sandwiched between the clean side case and the dirty side case. An eighth feature of the present invention is that the ridge portion is formed such that a tip end of the ridge portion abuts on the partition wall.

  According to the first feature of the present invention, the bottom wall of the clean chamber in the air cleaner is inclined to be gradually lowered toward one side in the vehicle width direction, and provided at the lowest portion of the bottom wall Since the upstream end of the intake passage, which is located gradually upward toward the air cleaner, is connected to the connection port, the fuel accumulated in the clean chamber by the blowback gas in the intake passage is returned to the connection port along the bottom wall of the clean chamber. As the fuel flows from the connection port to the intake passage located at a lower position toward the intake port, the fuel can be prevented from accumulating in the air cleaner and maintenance work for discharging the fuel becomes unnecessary. Can.

  Further, according to a second feature of the present invention, in the intake pipe member, a connection cylinder connected to the connection port integrally protrudes in a row with the cleaner case and forms an upstream end of the intake passage in the connection cylinder part. Since the upstream end is connected, the intake pipe member does not rush into the clean chamber of the air cleaner, and it becomes easy to return the fuel from the connection port to the intake passage side.

  According to a third aspect of the present invention, an inclination is provided on at least a portion of the bottom wall of the clean chamber, along the frame member inclined downward and backward through the air cleaner, in front of the connection port. A wall portion is formed, and the connection port is provided at the lowest portion of the inclined wall portion, so that the fuel in the clean chamber can be positively guided to the connection port side along the inclined wall portion, and furthermore, the air cleaner The air cleaner can have a sufficient capacity by extending a portion of the front along the frame member.

  According to the fourth aspect of the present invention, since the gas-liquid separation chamber for introducing the breather gas and performing gas-liquid separation is formed in the clean chamber at the rear of the connection port, the flow of fuel to the connection port is hindered. The gas-liquid separation chamber can be configured in the clean chamber at a position where it does not occur.

  According to the fifth aspect of the present invention, the cleaner element is held by the partition wall sandwiched between the clean side case and the dirty side case which cooperate to form the cleaner case, and the compartment is separated from the bottom wall of the clean chamber An isolation wall forming a recess opening on the wall side is integrally provided in the clean side case, and the gas-liquid separation chamber is the partition which is close to and opposed to the bottom wall of the clean chamber and the isolation wall and the open end of the recess. Since it is formed of a wall, the gas-liquid separation chamber is configured without using other members other than the clean case and the partition wall, and an increase in the number of parts is avoided to form the gas-liquid separation chamber. be able to.

  According to the sixth aspect of the present invention, since the rib extending along the separation wall in the gas-liquid separation chamber is integrally provided on the partition wall, a labyrinth passage is formed in the gas-liquid separation chamber Effective gas-liquid separation can be performed, and only gas can flow into the clean chamber.

  According to the seventh aspect of the present invention, the bottom wall of the dirty side case, which constitutes the cleaner case in cooperation with the clean side case, inclines to a lower position as it approaches the clean side case, A portion of the bottom wall of the dirty side case near the clean side case is provided with a drain hole for draining the moisture in the dirty chamber, and the drain hole is covered from above by the ridge portion integrally provided on the dirty side case. Water that has entered the air cleaner's dirty chamber can be drained well from the drain hole, and even if water or dust enters the dirty chamber from the drain hole, that water or dust will directly adhere to the cleaner element. Can be suppressed.

  Furthermore, according to the eighth feature of the present invention, since the tip of the buttocks abuts against the partition wall, the water and dust entering the dirty chamber through the drain hole rise along the partition wall by the intake air, and the cleaner element The buttocks can prevent going to the side.

Fig. 2 is a left side view of the motorcycle. It is the 2 arrow part enlarged view of FIG. It is line 3-3 in FIG. 2 sectional drawing. It is line 4-4 in FIG. 3 sectional drawing. It is the 5 arrow part enlarged view of FIG. It is a partially notched back view of the dirty side case seen from the 6 arrow direction of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. In the following description, the front, rear, left, right, up and down refer to directions as viewed from a passenger on a motorcycle.

  First, in FIG. 1, a vehicle body frame F of the motorcycle includes a head pipe 13 supporting a front fork 11 for pivotally supporting a front wheel WF at its lower end and a steering handlebar 12; And an upper frame 15 disposed above the main frame 14 and extending rearward from the head pipe 12, and a pair of left and right sides extending downward from the rear end of the main frame 14. A pivot frame 16 and a pair of left and right seat frames 17 continuously extending to the rear end portion of the upper frame 15 and extending rearward, and extending upward from the upper end portions of the pair of left and right pivot frames 16 And a pair of left and right rear frames 18 connected to the rear of the seat frame 17.

  A front end portion of a swing arm 19 on which the rear wheel WR is suspended is supported by the pivot frame 16 so as to be vertically swingable via a support shaft 20. A rear cushion unit 21 is provided between the rear portion of the swing arm 19 and the seat frame 17.

  The engine body 22 of the internal combustion engine E that exerts power to drive the rear wheel WR is supported by the main frame 14 of the vehicle body frame F and the pivot frame 16 with the cylinder axis C being inclined forward until it becomes substantially horizontal. The rotational power from the internal combustion engine E is transmitted to the rear wheel WR via a power transmission mechanism 24 having an endless drive chain 23.

  A fuel tank 25 disposed above the engine body 22 is supported by the upper frame 15 of the vehicle body frame F, and a tandem type passenger seat 26 disposed behind the fuel tank 25 It is supported by the seat frame 17.

  The intake device 28 of the internal combustion engine E is connected to an intake pipe 29 whose downstream end is connected to the upper side wall of a cylinder head 27 which constitutes a part of the engine body 22, and to the upstream end of the intake pipe 29 A carburetor 30 as a fuel supply means, an air cleaner 31 disposed behind the carburetor 30, and a connecting tube 32 connecting the carburetor 30 and the air cleaner 31 are provided.

  The exhaust device 33 of the internal combustion engine E is connected to an exhaust pipe 34 connected to the lower side wall of the cylinder head 27, an exhaust muffler 35 disposed below the engine main body 22, and the exhaust pipe 34. And a catalytic converter 36 housed in the exhaust muffler 35.

  Referring also to FIGS. 2 to 4, in the intake device 28, the downstream end is communicated with the intake port 38 of the cylinder head 27 in the engine body 22 and the upstream end is communicated with the clean chamber of the air cleaner 31. In the middle of the passage 39, a carburetor 30 for mixing fuel with intake air is interposed, and the air cleaner 31 is disposed rearward in the front-rear direction from the carburetor 30 with the internal combustion engine E mounted on a motorcycle. It is placed at a remote location.

  The intake passage 39 is formed in the intake pipe 29, the carburetor 30, and the connecting tube 32 so as to be gradually located at an upper position as it goes from the intake port 38 toward the air cleaner 31.

  The air cleaner 31 has a clean side case 41 forming a part of a clean chamber 44, a dirty side case 42 forming a part of a dirty chamber 45 and constituting a cleaner case 40 together with the clean side case 41, and a cleaner element A partition wall 43 is provided between the clean side case 41 and the dirty side case 42 by partitioning between the clean chamber 44 and the dirty chamber 45 while holding 46.

  The clean side case 41 and the dirty side case 42 are formed in a box shape with the partition wall 43 side open, and the fitting recess 47 provided on the entire circumference of the open end of the clean side case 41 A projection 43a provided on the outer periphery of the partition wall 43 is fitted so as to sandwich the seal member 48 with the clean side case 41, and the outer periphery of the partition wall 43 corresponds to the clean side case 41 and the dirty side case 42. The clean-side case 41 and the dirty-side case 42 are mutually fastened by a plurality of bolts 49 arranged at intervals in the circumferential direction while being sandwiched between the open ends.

  A rectangular holding cylindrical portion 43 b is integrally provided at a substantially central portion of the partition wall 43, and the cleaner element 46 is accommodated and held in the holding cylindrical portion 43 b.

  The air cleaner 31 arranges the clean chamber 44 on the left side of the partition wall 43 and arranges the dirty chamber 45 on the right side of the partition wall 43 while forming a part of the vehicle body frame F Are disposed at the upper rear of the main frame 14. Upper mounting plate portions 41a are respectively provided at two places spaced in the front and rear of the upper portion of the clean side case 41 in the cleaner case 40, and fixed to the right one of the pair of left and right seat frames 17 The upper mounting plate portion 41 a is fastened to the pair of front and rear upper stays 50 with bolts 51. Further, a lower mounting plate portion 41b provided at the rear lower portion of the clean case 41 is fastened to a lower stay 52 fixed to the rear end portion of the main frame 14 and extending upward by bolts 53.

  As described above, the bottom wall 55 of the clean chamber 44 formed in the cleaner case 40 is supported by the seat frame 17 and the main frame 14 of the vehicle body frame F in one of the vehicle width directions (this embodiment Then, it is arranged to be gradually inclined downward toward the left).

  In order to suck air from the outside into the dirty chamber 45 from the rear of the air cleaner 31, a suction cylinder 56 is integrally projected on the dirty side case 42 so as to open rearward. Further, a connection port 57 for communicating the upstream end of the intake passage 39 so as to guide clean air from the clean chamber 44 to the intake passage 39 becomes the bottom wall 55 of the clean chamber 44 in the clean side case 41. It is provided in the part. Further, the bottom wall 55 is inclined so as to be gradually lowered toward the left in the vehicle width direction, and the connection port 57 is provided at the lowest portion of the bottom wall 55.

  A connecting cylinder 58 is formed integrally with the clean side case 41 of the cleaner case 40. The connecting cylinder 58 extends outward from the clean side case 41 so as to be continuous with the connection port 57. The upstream end of the connecting tube 32 which is an intake pipe member to be formed is connected to the connecting cylinder 58.

  By the way, the main frame 14 is inclined downward and backward through the lower side of the air cleaner 31, and at least a part (a part in this embodiment) of the bottom wall 55 of the clean chamber 44 is the main An inclined wall portion 55a disposed forward of the connection port 57 is formed along the frame 14, and the connection port 57 is provided at the lowest portion of the inclined wall portion 55a.

  Referring also to FIG. 5, one end of a hose 60 for leading the breather gas from the inside of the crankcase 59 is connected to the crankcase 59 of the engine body 22, and the breather gas led by the hose 60 is the connection It is introduced into the gas-liquid separation chamber 61 formed in the clean chamber 44 so as to be disposed behind the port 57, and the gas-liquid separation is performed in the gas-liquid separation chamber 61.

  A separation wall 63 forming a recess 62 opened to the side of the partition wall 43 between the clean chamber 44 and the bottom wall 55 is integrally provided on the clean case 41, and the gas-liquid separation chamber 61 is A bottom wall 55 of the clean chamber 44 and the separating wall 63 and the dividing wall 43 adjacent to and facing the open end of the recess 63 are formed.

  Moreover, since the bottom wall 55 of the clean chamber 44 is gradually inclined downward toward the left in the vehicle width direction, the gas-liquid separation chamber 61 is also inclined in the same direction as the bottom wall 55. The other end of the hose 60 is connected to a breather gas introduction cylinder 64 integrally formed on the bottom wall 55 so as to communicate with the lowest part of the gas-liquid separation chamber 61.

  Moreover, the partition wall 43 is integrally provided with a rib 65 extending along the separation wall 63 in the gas-liquid separation chamber 61.

  In FIG. 6, the bottom wall 42a of the dirty side case 42 forming the bottom of the dirty chamber 45 is formed to be inclined downward as it approaches the clean side case 41, and the dirty side case 42 is formed. A drain hole 66 for draining water in the dirty chamber 45 is provided in a portion of the bottom wall 42a closer to the clean case 41, and a ridge portion 67 covering the drain hole 66 from above is the dirty case 42 integrally provided.

  Moreover, the flange portion 67 is formed so that the tip of the flange portion 67 abuts on the partition wall 43.

  Next, the operation of this embodiment will be described. In the vehicle mounted state, the air cleaner 31 is disposed at a position separated rearward in the front-rear direction from the carburetor 30, and a clean chamber 44 formed in the cleaner case 40 of the air cleaner 31. Bottom wall 55 is gradually inclined downward toward one side (left in this embodiment) in the vehicle width direction, and the air cleaner 38 is installed at the lowest portion of the bottom wall 55 from the intake port 38 Since the connection port 57 is provided to allow the upstream end of the intake passage 39 to gradually communicate with the side 31 toward the upper side, the fuel accumulated in the clean chamber 44 by the blowback gas in the intake passage 39 is the bottom wall 55 of the clean chamber 44. And the air is returned to the connection port 57 side, and the intake port is located at a lower position from the connection port 57 toward the intake port 38 side. Since fuel flows to the road 39, to prevent the fuel accumulated in the cleaner 31, the maintenance work for the fuel discharge can be eliminated.

  Further, the cleaner case 40 is integrally formed with a connecting cylinder 58 which protrudes outward from the cleaner case 40 continuously with the connection port 57, and forms the upstream end of the intake passage 39 at the upstream end of the connecting tube 32. Since the connecting portion is connected to the connection cylinder 58, the connecting tube 32 does not rush into the clean chamber 44 of the air cleaner 31, and it becomes easy to return the fuel from the connection port 57 to the intake passage 39 side.

  Further, the vehicle body frame F includes a main frame 14 inclined downward and backward through the lower part of the air cleaner 31, and at least a part of the bottom wall 55 of the clean chamber 44 is connected along the main frame. Since the inclined wall 55a disposed forward of the opening 57 is formed, and the connection port 57 is provided at the lowest part of the inclined wall 55a, the fuel in the clean chamber 44 is made to follow the inclined wall 55a. Thus, the capacity of the air cleaner 31 can be secured by extending a part of the air cleaner 31 forward along the main frame 14.

  In addition, a gas-liquid separation chamber 61 that performs gas-liquid separation by introducing breather gas from the crankcase 59 of the engine body 22 is formed in the clean chamber 44 so as to be disposed rearward of the connection port 57. Therefore, the gas-liquid separation chamber 61 can be configured in the clean chamber 44 at a position where the flow of fuel to the connection port 57 is not hindered.

  Further, the air cleaner 31 includes a clean side case 41 forming a part of the clean chamber 44, and a dirty side case 42 forming a part of the dirty chamber 45 and configuring the cleaner case 40 together with the clean side case 41; A partition wall 43 for partitioning between the clean chamber 44 and the dirty chamber 45 while holding the cleaner element 46 and being sandwiched between the clean case 41 and the dirty case 42; and the bottom of the clean chamber 44 A separation wall 63 forming a recess 62 opened to the side of the partition wall 43 with the wall 55 is integrally provided in the clean side case 41, and the gas-liquid separation chamber 61 is a bottom wall 55 of the clean chamber 44. And the separating wall 64 and the dividing wall 43 adjacent to and facing the open end of the recess 62, the gas-liquid separation chamber 1, can be configured without using members other than the clean side case 41 and the partition wall 43, to prevent the number of parts is increased in order to constitute a gas-liquid separation chamber 61.

  Further, since the rib 65 extending along the separation wall 63 in the gas-liquid separation chamber 61 is integrally provided on the partition wall 43, a labyrinth passage is formed in the gas-liquid separation chamber 61 to form the gas-liquid separation chamber 61. Effective gas-liquid separation can be performed internally, and only the gas can flow into the clean chamber 44.

  The bottom wall 42a of the dirty side case 42 forming the bottom of the dirty chamber 45 is formed to be inclined downward as it approaches the clean side case 41, and the bottom wall 42a of the dirty side case 42 has the bottom wall 42a. A drain hole 66 for draining water in the dirty chamber 45 is provided at a portion near the clean case 41, and a flange portion 67 covering the drain hole 66 from above is provided integrally with the dirty case 42. The moisture which has entered the dirty chamber 45 of the air cleaner 31 can be satisfactorily drained from the drain hole 66, and even if water or dirt enters the dirty chamber 45 from the drain hole 66, the moisture or dust is a cleaner element Direct adhesion to 46 can be suppressed by the heel portion 67.

  Further, since the ridge portion 67 is formed so that the tip end of the ridge portion 67 abuts on the partition wall 43, water or dust which has entered the dirty chamber 45 from the drain hole 66 is divided by the intake air. It can be prevented by the hook portion 67 that ascends 43 and rises toward the cleaner element 46 side.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various design change is made, without deviating from this invention described in the claim. Is possible.

  For example, although the above-mentioned embodiment explained the case where the present invention was applied to the two-wheeled motor vehicle, the present invention can be widely practiced in connection with a small vehicle including a three-wheeled motor vehicle.

  Further, the present invention may be applied to an intake system in which a throttle body is used instead of the carburetor 30 of the above embodiment and a fuel injection valve as a fuel supply means is attached to the throttle body or the intake pipe. it can.

14 Main frame 22 as a frame member Engine main body 30 Vaporizer 31 as a fuel supply means Air cleaner 32 Connecting tube 38 as an intake pipe member Intake port 39 ... Intake passage 40 ... Cleaner case 41 ... Clean side case 42 ... Dirty side case 42 a ... Bottom wall 43 of dirty side case ... Partition wall 44 ... Clean room 45 ... Dirty chamber 46: Cleaner element 55: Bottom wall of clean chamber 55a: Inclined wall 57: Connection port 58: Connection cylinder 61: Gas-liquid separation chamber 62: Recess 63 ... separating wall 65 ... rib 66 ... drain hole 67 ... buttocks F ... body frame

Claims (8)

  An intake passage (39) whose downstream end is in communication with the intake port (38) of the engine body (22) mounted on the vehicle body frame (F) and whose upstream end is in communication with the clean chamber (44) of the air cleaner (31). In the intake system of the internal combustion engine for a small vehicle, in which a fuel supply means (30) for mixing the fuel with the intake air is interposed in the middle, the position separated from the fuel supply means (30) in the longitudinal direction The air cleaner (31) is disposed at the bottom, and the bottom wall (55) of the clean chamber (44) formed in the cleaner case (40) of the air cleaner (31) is gradually lowered toward one side in the vehicle width direction. And the lower end of the bottom wall (55) is gradually moved upward from the intake port (38) toward the air cleaner (31). The intake system for a small vehicle internal combustion engine upstream end of the through make connection port (57) and which are located in the intake passage (39). The cleaner case (40) is integrally formed with a connecting cylinder (58) which protrudes outward from the cleaner case (40) continuously with the connection port (57), and the upstream end of the intake passage (39) intake system for a small vehicle internal combustion engine according to claim 1, upstream end, characterized in that it is connected to the connecting tube (5 8) of the intake pipe member forming (32) a.
  The vehicle body frame (F) includes a frame member (14) which is inclined rearwardly and downwardly through the air cleaner (31), and at least a part of the bottom wall (55) of the clean chamber (44), An inclined wall (55a) disposed forward of the connection port (57) is formed along the frame member (14), and the connection port (57) is the lowest of the inclined wall (55a). The intake system for an internal combustion engine for a small vehicle according to claim 2, wherein the intake system is provided in a part.   In the clean chamber (44), a gas-liquid separation chamber (61) performing gas-liquid separation by introducing a breather gas from the engine main body (22) is disposed rearward of the connection port (57). The intake system for an internal combustion engine for a small vehicle according to any one of claims 1 to 3, which is formed in   The air cleaner (31) includes a clean case (41) forming a part of the clean chamber (44), and a part of a dirty chamber (45) to form the cleaner case together with the clean case (41). The clean side case (41) and the dirty side case (42) constituting the (40), and the clean room (44) and the dirty room (45) are partitioned while holding the cleaner element (46) A recess (62) having a partition wall (43) sandwiched between the dirty side cases (42) and opening to the partition wall (43) between the clean chamber (44) and the bottom wall (55); And the separation wall (63) forming an integral part of the clean case (41), and the gas-liquid separation chamber (61) includes a bottom wall (55) of the clean chamber (44) and the separation wall. 63), the proximity to the open end of the recess (62), an intake apparatus of a small vehicle internal combustion engine according to claim 4, characterized in that it is formed out with the partition wall facing (43).   The small vehicle according to claim 5, characterized in that the partition wall (43) is integrally provided with a rib (65) extending along the separation wall (63) in the gas-liquid separation chamber (61). Device for internal combustion engines.   The cleaner case (40) is combined with the clean side case (41) which forms a part of the clean chamber (44), and a part of the dirty chamber (45). The bottom wall (42a) of the dirty side case (42), which comprises the dirty side case (42) and forms the bottom of the dirty chamber (45), is positioned lower as it approaches the clean side case (41) A drain for draining the water in the dirty chamber (45) to a portion near the clean side case (41) of the bottom wall (42a) of the dirty side case (42). The method according to any one of claims 1 to 6, wherein a hole (66) is provided, and a collar (67) covering the drain hole (66) from above is integrally provided in the dirty case (42). Or intake system for a small vehicle internal combustion engine according to (1).   A partition wall (43) partitioning between the clean chamber (44) and the dirty chamber (45) while holding the cleaner element (46) is between the clean case (41) and the dirty case (42). The internal combustion engine according to claim 7, characterized in that the flange portion (67) is formed such that the tip end of the flange portion (67) abuts on the partition wall (43). Engine intake system.

Images