AU2013207656A1 - Air cleaner case structure for straddle type vehicle - Google Patents

Abstract

AIR CLEANER CASE STRUCTURE FOR STRADDLE TYPE VEHICLE In an air cleaner case structure for a straddle type vehicle which has an internal combustion engine (1), an air cleaner case (40) arranged in the rear of the internal combustion engine (1), and a rider's seat (33) covering these internal combustion engine (1) and air cleaner case (40) from above, a connecting tube (6) extending to the internal combustion engine (1), is provided on a front side of the air cleaner case (40). A space for an exhaust pipe (37) is provided on one lateral side of left and right sides of the air cleaner case (40). An opening lid portion (47) for performing maintenance of a cleaner element (9) within the air cleaner case (40) is provided on the other of the left and right sides of the air cleaner case (40). An air intake port (48) is arranged on an upper portion of the air cleaner case (40). A battery housing section (43) for accommodating a battery (8) for supplying ignition energy to the internal combustion engine (1) is extended in a rear part of the air cleaner case (40). coo -coo -0 C~0 l) c 0( (0 C'

Description

1 AIR CLEANER CASE STRUCTURE FOR STRADDLE TYPE VEHICLE Technical Field [0001] The present invention relates to an air cleaner case structure for a straddle type vehicle capable of improving maintainability. Background Art [0002] Hitherto, a straddle type vehicle that is of the type comprising an air cleaner case being located in the rear of an internal combustion engine, a battery being arranged on the left side in the vehicle width direction of the air cleaner case, and a lid of the air cleaner case being arranged on the right side thereof is disclosed in a patent reference 1, for example. In the vehicle disclosed in the patent reference 1, however, in the case of the straddle type vehicle in which an exhaust pipe and a silencer are arranged on the right side of a vehicle body, it is required in arrangement of the exhaust pipe to figure out the way to avoid a location of the lid of the air cleaner case. Therefore, it is desired to provide the air cleaner structure which optimizes the layout of the exhaust pipe and further improves the maintainability. [0003] Patent reference 1: Japanese patent laid-open publication No. 2004-011558 (FIG. 1-FIG. 6). Object of the Invention [0004] It is the object of the present invention to substantially overcome or at least ameliorate one or more of the foregoing disadvantages. Summary of the Invention [0005] According to the present invention, there is provided an air cleaner case structure for a straddle type vehicle which has an internal combustion engine, an air cleaner case arranged in the rear of the internal combustion engine, and a rider's seat covering these internal combustion engine and air cleaner case from above, comprising a connecting tube which extends to the internal combustion engine, being provided on a front side of the air cleaner case, a space for an 2 exhaust pipe being provided on one lateral side of left and right sides of the air cleaner case, an opening lid portion for performing maintenance of a cleaner element within the air cleaner case, being provided on the other of the left and right sides of the air cleaner case, an air intake port being arranged on an upper portion of the air cleaner case, and a battery housing section for accommodating a battery for supplying ignition energy to the internal combustion engine, being extended in a rear part of the air cleaner case. [0006] Preferably, there is provided a rear cushion being arranged between the internal combustion engine and the air cleaner case in the rear of the internal combustion engine, wherein the connecting tube is so formed as to make a detour in the vehicle width direction to avoid the rear cushion, and the opening lid portion is arranged on the same lateral side of the vehicle as the connecting tube. [0007] Preferably, an air intake passage of the connecting tube is connected to an upward part of the air cleaner case, and a breather return chamber for receiving blow-by gas from the internal combustion engine is formed in a lower part of the connecting tube. [0008] Preferably, a pair of mounting bosses are provided on a left and right sides of the battery housing section of the rear part of the air cleaner case. [0009] Preferably, a breather tube extending from the internal combustion engine to be connected to the breather return chamber is plumbed in such a manner as to be bent in substantially an S-shaped form in a plan view above a crankcase of the internal combustion engine. [0010] Preferably, the breather return chamber is formed between a recess portion of the connecting tube and a support plate of the cleaner element and is in communication with the upwardly located air intake passage of the connecting tube through a gas-liquid separation passage provided in the support plate. [0011] According to the air cleaner case structure for the straddle type vehicle in an embodiment of the present invention, since the battery is supported on the rear part of the air cleaner case, maintenance of the battery can be easily performed by setting the rider's seat upright, and an air intake system can be effectively arranged without interference with the battery. In addition, since the exhaust pipe and the opening lid portion of the air cleaner case are 3 arranged on the opposite sides in the vehicle width direction of the air cleaner case, the layout of the exhaust pipe can be optimized, so that an increase of a width of the vehicle body in the vehicle width direction can be restrained, and the maintenance of the air intake system such as the cleaner element or the like can be performed without obstruction by the exhaust pipe or the like, whereby to improve the maintainability. [0012] According to an embodiment of the present invention, in addition to the effects of the first aspect, since the maintenance of the connecting tube and of the cleaner element is able to be performed from the same direction, the maintenance time can be shortened whereby to further improve the maintainability. Particularly, in a race or the like, the shortening of the maintenance time is more important, so that the above is effective. [0013] According to an embodiment of the present invention, in addition to the effects of the second aspect, since the maintenance of a breather system such as the breather tube, a drain cap of a drain discharge pipe or the like is able to be performed in the same direction as the maintenance of the cleaner element, the maintainability can be further improved. [0014] According to an embodiment of the present invention, in addition to the effects of any one of the first to third aspects, since the air cleaner case is so formed as to be supported on the left and right sides of the battery housing section, the heavy battery can be efficiently carried on the air cleaner case, and the opening lid portion can be made larger, whereby to improve the maintainability. [0015] According to an embodiment of the present invention, in addition to the effects of the third aspect, since the breather tube is plumbed in such a manner as to be bent in substantially an S-shaped form, the length of the breather tube is ensured so that the mutual movement between the internal combustion engine and the air cleaner case can be absorbed, and mixed oil flowing into the breather tube due to a sharp inclination of the vehicle can be stored and restrained from flowing out. [0016] According to an embodiment of the present invention, in addition to the effects of the third or fifth aspect, since the gas-liquid separation structure is simplified and the gas-liquid separation passage through which the blow-by gas flows is connected in the upward direction to the air intake passage of the connecting tube, the gas-liquid separation can be efficiently 4 performed and the influence of the breather return gas upon the internal combustion engine can be decreased. Brief Description of the Drawings [0017] A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings in which: FIG. 1 is a right side schematic view of a two wheeled motorcycle provided with an air cleaner case according to an embodiment of the present invention; FIG. 2 is a right side view of an essential part around an air cleaner of the motorcycle in FIG. 1; FIG. 3 is a left side view of an essential part showing an internal combustion engine and the air cleaner of the motorcycle in FIG. 1, in which the air cleaner case is shown in a state of exposing an interior thereof by removing an opening lid portion which covers a left lateral opening thereof; FIG. 4 is a top plan view of an essential part showing the internal combustion engine and the air cleaner of the motorcycle in FIG. 1, in which a connecting tube and the air cleaner case are shown in cross section taken in the direction of arrows generally along line IV-IV in FIG. 3; FIG. 5 is an exploded view schematically showing the construction of essential components of the air cleaner according to the embodiment of the present invention; FIG. 6 is a left side view of the air cleaner according to the embodiment of the present invention; FIG. 7 is a rear view of the air cleaner taken in the direction of arrows VII-VII in FIG. 6; FIG. 8 (a) is a left side view of the connecting tube, and FIG. 8 (b) is a rear end view thereof taken in the direction of arrows b-b in FIG. 8 (a); and 5 FIG. 9 is a rear view of an element support plate corresponding to substantially a view taken in the direction of arrows IX-IX in FIG. 6, in which for the sake of explanation, the forwardly locating connecting tube is overlapped and illustrated by a dotted line.

6 Description of Embodiments [0018] An air cleaner case structure of a straddle type vehicle according to an embodiment of the present invention will be described hereunder with reference to accompanying drawings of FIG. I to FIG 7. In the following description and claims of this specification, the orientation such as front, rear, left, right, upper, lower and the like shall be set on the basis of the orientation of the straddle type vehicle on which an air cleaner having the air cleaner case structure of the straddle type vehicle according to the embodiment of the present invention is mounted. In this embodiment, the straddle type vehicle is a two-wheeled motorcycle. Moreover, in the drawings, an arrow FR designates a forward direction of the vehicle, an arrow LH designates a left direction of the vehicle, an arrow RH designates a right direction of the vehicle, and an arrow UP designates an upper direction the vehicle, respectively. In addition, in the drawings, a solid black arrow designates a flow of blow-by gas and a solid white arrow designates a flow of intake air in a schematic fashion according to the embodiment of the present invention. [0019] FIGS. 1 to 9 show one embodiment of the present invention, wherein FIG. 1 is a right side schematic view showing the motorcycle of the embodiment. An internal combustion engine 1 according to this embodiment is provided integral with a transmission 12 in the rear part of a crankcase 10 so as to constitute the so-called power unit and is an air-cooled single cylinder four stroke cycle internal combustion engine which is mounted on a two-heeled motorcycle 2 such that a crankshaft 11 extends in a vehicle width direction of the motorcycle 2, namely in a left and right direction. [0020] As shown in FIG. 1, a vehicle body frame 20 of the motorcycle 2 equipped with the internal combustion engine 1 according to the present embodiment has a pair of left and right main frames 22 which extends backwardly and slightly downwardly from a head pipe 21 and then is bent downwardly to form a steeply inclined section 22a which reaches a lower end. A pair of left and right down frames 23 extends obliquely downwardly at an acute angle from the head pipe 21 in substantially parallel with the steeply inclined section 22a of the main frame 22 in a side view. [0021] A pair of left and right seat rails 24 extends backwardly from an upper portion of the steeply inclined section 22a of the main frame 22. A pair of left and right back stays 25 connecting a central portion of the seat rail 24 and a lower portion of the steeply inclined section 22a supports the left and right seat rails 24 respectively. [0022] In the vehicle body frame 20 as above, a front fork 26 is pivotally supported on the head pipe 21. On a lower end of the front fork 26, front wheel 27 is pivotally supported. A rear fork 28 swingably supported at a front end thereof on the lower portion of the steeply inclined section 22a of the main frame 22 extends backwardly so as to pivotally support a rear wheel 29 at a rear end thereof. A rear cushion 31 extends between the rear fork 28 and a gusset 30 provided on the steeply inclined section 22a. 7 A fuel tank 32 is mounted on a front part of the main frame 22, and a rider's seat 33 is provided at the rear of fuel tank 32 while being supported by the seat rail 24. [0023] Although the internal combustion engine 1 supported by the main frame 22 and the down frame 23 is integrally provided with the transmission 12 as referred to above, a cylinder block 13, a cylinder head 14 and a cylinder head cover (not shown) are provided in a standing fashion on the crankcase 10 in such a manner that a cylinder axis C is inclined slightly forwardly. [0024] An inlet pipe 35 connected to an inlet port 16 extends backwardly from the cylinder head 14 of the internal combustion engine 1 via carburetor 36 to an air cleaner 4. An exhaust pipe 37 connected to an exhaust port 17 extends forwardly from the cylinder head 14. The exhaust pipe 37 is bent in a lower right direction and extends backwardly through a right side of the cylinder block 14 of the internal combustion engine 1 whereby to be connected to a silencer 38 located on a right side of the rear wheel 29. [0025] FIG. 2 is a right side view of an essential part showing the air cleaner and its environs of the motorcycle in FIG. 1, wherein an air cleaner case 40 of the air cleaner 4 is arranged in the rear of the internal combustion engine 1 and covered with the rider's seat 33 from above. In addition, the exhaust pipe 37 passes through a right lateral side of the air cleaner case 40. Therefore, a recess 40a is formed on a right side surface of the air cleaner case 40 so as to provide a space for the exhaust pipe 37. [0026] In a rear part of the air cleaner case 40 there is extended a battery housing section 43 for accommodating a battery 8 for supplying ignition energy to the internal combustion engine 1. The battery 8 is held in the battery housing section 43 by a battery holding band 80. Battery band hooks 44L, R are provided left and right for fixing the battery holding band 80 thereon (see FIG. 3 together). 8 Moreover, the air cleaner case 40 is mounted on the right seat rail 24 by a front mounting boss 41 provided in the front upper part thereof. On the rear side, the air cleaner case 40 is mounted on each of the right and left back stays 25 by a right mounting boss (as a pair of vehicle body mounting bosses in the present invention) 42R provided on the right side of the battery housing section 43 and by a left mounting boss (as a pair of vehicle body mounting bosses in the present invention) 42L provided on the left side of the battery housing section 43 (see FIG. 3). [0027] FIG. 3 is a left side view showing an essential part of the internal combustion engine I and the air cleaner 4 of the motorcycle 2. As shown in FIG. 3, the air cleaner case 40 of the air cleaner 4 is connected in the rear of the internal combustion engine 1 to an upstream side of the carburetor 36 through a connecting tube 6. In FIG. 3, the air cleaner case 40 is shown in a state of exposing an interior thereof by removing an opening lid portion 47 (see FIGS. 5 and 6) which covers a left lateral opening 46 thereof. The opening lid portion 47 is provided for performing maintenance of the cleaner element 9 within the air cleaner case 40 while leaving the left lateral opening 46 open. An air intake port 48 is arranged on an upper part of the air cleaner case 40. [00281 The connecting tube 6 is provided at the upper inside thereof with an air intake passage 60 connected to the carburetor 36. A rear end (upstream end) 60a (see FIG. 8) of the air intake passage 60 is connected to an upward side of the air cleaner case 40. A recess portion 6a is formed on a lower part of the air intake passage 60 of the connecting tube 6, and a partition wall 61 which defines the air intake passage 60 is formed in an interior of the recess portion 6a. A breather return chamber 62 for receiving blow-by gas from the internal combustion engine 1 is formed between a lower side of the partition wall 61 and an element support plate (as a support plate in the present invention) 7 (see FIGS. 5 and 9) which comes in contact from a case inside with a front opening 45 of the air cleaner case 40 to be referred to later (see 9 FIG. 8). [0029] A front end (downstream end) 60b of the air intake passage 60 is connected to an upstream side of the carburetor 36. On the breather return chamber 62 there is provided a forwardly extending blow-by gas return joint 62a to which a downstream end 63b of the breather tube 63 is connected. An upstream end 63a of the breather tube 63 is connected to an L-shaped joint 64 located in the upper part of the crankcase 10, whereby to be in communication with an interior of the crankcase 10. [0030] As shown in FIG. 3, in a left side view, the air cleaner case 40 is mounted on the left back stay 25 through the left mounting boss 42L provided on the left side of the battery housing section 43. Also, to the left side of the battery housing section 43, the left battery band hook 44L is attached such as to hook or engage the battery holding band 80 together with the right battery band hook 44R on the right side whereby to hold the battery 8 (see FIG. 7 as well). [0031] In FIG. 3, a reference character 51A denotes a front buckle for fixing the opening lid portion 47 on a front rim side of the left lateral opening 46 of the air cleaner case 40, and 51B denotes a rear buckle for fixing the opening lid portion 47 on a rear rim side. The buckle 51A is attached to a holder plate 55 (see FIGS. 5 and 6) which is fastened together with the buckle 51A on the connecting tube 6 to be referred to later, and the rear buckle 51B is attached to a forward extension 44La of the left battery band hook 44L whereby to hold the opening lid portion 47 from outside to fix the same in a detachable fashion (see FIG. 6). Namely, a peripheral rim portion 46a on the front rim side of the left lateral opening 46 is fitted to and fixed on an engaging groove 47a provided on a peripheral rim portion of the opening lid portion 47 in a state of putting an opening lid seal 47b between the peripheral rim portion 46a and the engaging groove 47a. The same way shall be applied to the rear rim side of the left lateral opening 46. 10 [0032] The cleaner element 9 provided therein with an element holder 91 is inserted into the interior of the air cleaner case 40 through the left lateral opening 46 and fixed on while being pressed against a front wall 50 side with a presser metal fitting 93. [0033] FIG. 4 is a top plan view showing an essential part of the internal combustion engine 1 and the air cleaner 4 of the motorcycle 2, in which the connecting tube 6 and the air cleaner case 40 are shown in cross section taken in the direction of arrows generally along line IV-IV in FIG. 3, and the cleaner element 9 and the opening lid portion 47 are removed. As shown in FIG. 4, the rear cushion 31 is located midway in the forward and backward direction between the internal combustion engine 1 and the air cleaner 4 and in a center position in the vehicle width direction. The connecting tube 6 is so formed as to make a detour in the vehicle width direction to avoid the rear cushion 31, and the opening lid portion 47 is arranged on the same left lateral side of the vehicle as the connecting tube 6 (see FIGS. 5 and 7). [0034] On a rear end of the connecting tube 6 there is formed a flange portion 65 extending in an outer direction around the periphery. An engaging groove 66 provided around the periphery of an outer lateral surface of the flange portion 65 (see FIG. 8) is formed along an inner peripheral rim 45a of the front opening 45 provided on the front wall 50 of the air cleaner case 40, so that the inner peripheral rim 45a of the air cleaner case 40 is fitted into the engaging groove 66, thus allowing the connecting tube 6 to be attached to the air cleaner case 40. [0035] Then, the annular holder plate 55 is arranged while allowing the air intake passage 60 of the connecting tube 6 and the breather return chamber 62 to pass through it, in such a manner as to bias from a front side an engaging section 49 between the air cleaner case 40 and the connecting tube 6. At the same time, the element support plate 7 comes in contact with 11 the engaging section 49 such as to bias the same from a rear side. Thereafter, forwardly extending fastening bolts 71 (see FIGS. 5 and 9) which are secured by welding to the element support plate 7 are bolted in six fastening holes 65a (see FIGS. 5 and 8) which are formed in the flange portion 65 of the connecting tube 6, whereby the connecting tube 6 is fixed by the fastening bolts 71. [0036] Namely, on the annular holder plate 55 there are formed fastening holes 55a (see FIG. 5) corresponding to the fastening holes 65a of the flange portion 65. Also, on the front wall 50 of the air cleaner case 40 there are formed fastening holes 50a (see FIG. 5) corresponding to the fastening holes 65a of the flange portion 65. The fastening bolts 71 of the element support plate 7 are inserted from the rear side into the fastening holes 65a, the fastening holes 50a and the fastening holes 55a and tightened together with fastening nuts 72 (see FIGS. 3 and 6), so that the flange portion 65 of the connecting tube 6 is held between the holder plate 55 and the element support plate 7 thereby being fixed on the front wall 50 of the air cleaner case 40 (see FIG. 5). By the way, the engaging section 49 between the engaging groove 66 of the connecting tube 6 and the inner peripheral rim 45a of the air cleaner case 40 is bonded to be sealed in an air-tight fashion. [0037] FIG.4 is a top plan view partially in cross section of a lower part of the connecting tube 6, in which there is shown the breather return chamber 62 formed in the lower part of the air intake passage 60 which is connected to the carburetor 36. On the breather return chamber 62 there is provided the forwardly extending blow-by gas return joint 62a to which the downstream end 63b of the breather tube 63 is connected. The upstream end 63a of the breather tube 63 is connected to the L-shaped joint provided on the upper part of the crankcase 10 of the internal combustion engine 1, and the breather tube 63 is plumbed while being bent in an S-shaped form in a plan view, to communicate with the interior of the crankcase 10 whereby the 12 blow-by gas from the internal combustion engine 1 is received in the breather return chamber 62. [0038] In the straddle type vehicle such as the two-wheeled motorcycle, etc., there may be cases where the vehicle sharply inclines and vibrates. In such a case, since the breather tube 63 is plumbed in such a manner as to be bent in substantially an S-shaped form, the length of the breather tube 63 is ensured so that the mutual movement between the internal combustion engine 1 and the air cleaner case 40 is absorbed, and in the case where oil flows into the breather tube 63 due to the sharp inclination of the vehicle, the mixed oil flowing into the breather tube 63 is stored in the bent portion of the breather tube 63, and it is possible to return the mixed oil to the initial place by the inclination to the opposite side or the like, whereby the outflow of the oil from the internal combustion engine 1 can be restrained. [0039] Construction of main components of the air cleaner 4 according to this embodiment will be shown schematically in an exploded view of FIG. 5. In the drawing, a reference character 6 denotes the connecting tube which is attached to the air cleaner case 40 such as to engage the inner peripheral rim 45a (see FIG. 4) of the front opening 45 of the cleaner case 40 into the engaging groove 66 (see FIG. 8) of the flange portion 65 located on the peripheral rim of the connecting tube 6. The holder plate 55 is set from the front side in a state of allowing the air intake passage 60 portion and the breather return chamber 62 portion of the connecting tube 6 to be inserted therein. [0040] A reference character 9 denotes the cleaner element in an inner space 90 of which an element holder 91 of retaining frame shape is inserted and fitted from a forward element opening 9a. The cleaner element 9 can be inserted in and taken out of the left lateral opening 46 opened by removing the opening lid portion 47 of the cleaner case 40. Namely, it is replaceable. [0041] 13 In FIG. 5, 7 denotes the element support plate which is provided with an air intake opening 7a communicating only with the air intake passage 60 of the connecting tube 6 and on the periphery of which a plurality (six in this embodiment) of forwardly extending fastening bolts 71 are secured by welding. An element guard 74 of wire mesh shape is provided on the air intake opening 7a to cover a rear side thereof. The element support plate 7 is inserted in the air cleaner case 40 from the left lateral opening 46 of the air cleaner case 40. The fastening bolts 71 are inserted into the fastening holes 65a of the connecting tube 6 and the fastening holes 50a of the air cleaner case 72 to be engaged with each other, and then inserted into the fastening holes 55a of the holder plate 55. When the fastening nuts 72 (see FIGS. 3 and 6) are tightened up on the fastening bolts 71 from the front side, the connecting tube 6 is fixed on the air cleaner case 40. At that time, the engaging section 49 between the connecting tube 6 and the air cleaner case 40 is bonded and fixed in an air-tight fashion. Namely, the connecting tube 6, the air cleaner case 40 and the element support plate 7 are normally used in the mutually fixed condition. [0042] Further, a plurality of fixing pins 91a (two fixing pins in this embodiment) of the element holder 91 project forwardly from the cleaner element 9 in which the element holder 91 is inserted and fitted, through pin holes 9b of the cleaner element 9. The cleaner element 9 inserted in the air cleaner case 40 is fixed in position such that the fixing pins 91a are inserted forwardly from the rear side into pin holes 73 provided in the element support plate 7. [0043] In addition, the air intake port 48 is provided in an upper wall of the air cleaner case 40, and an inlet duct 48a is fitted to the air intake port 48. On the rear part of the air cleaner case 40, the battery housing section 43 is integrally formed. Moreover, in a left lateral surface of the air cleaner case 40 there is formed the fully opened left lateral opening 46. The left lateral opening 46 is closed when the opening led section 47 is fitted through the opening lid seal 47b to it. 14 [0044] FIG. 6 shows a left side view of the air cleaner 4 according to this embodiment. In FIG. 6, the left lateral opening 46 of the air cleaner case 40 is closed by the opening lid portion 47 attached thereto. The opening lid portion 47 is detachably fixed at two places on the forward side by the front buckles 51A and detachably fixed at two places on the backward side by the rear buckles 51B. The front buckle 51A is rotatably supported by a rotation support member 55b provided on a left rim portion of the holder plate 55, while the rear buckle 51 B is rotatably supported by the forward extension 44La of the right battery band hook 44L (see FIG. 7). In FIG. 6, the inlet duct 48a of the air intake port 48 is attached to the upper wall of the air cleaner case 40. A reference character 52 denotes a drain discharge pipe which is provided in communication with an interior of a bottom of the air cleaner case 40 and which is normally closed with a drain cap 52a. [0045] As schematically shown by a dotted line in FIG. 6, the cleaner element 9 inserted in the air cleaner case 40 is pressed forwardly to and abuts on the element support plate 7 in such a manner that a prop 91b which extends backwardly from the center of the element holder 91 inserted and fitted in the cleaner element 9 and which passes through the cleaner element 9 so as to project backwardly is pressed forwardly to the element support plate 7 by the presser metal fitting 93 bridged between the inner surface of the air cleaner case 40 and the element support plate 7. The presser metal fitting 93 is hooked and mounted at each end thereof on a case side hook 94 attached to the right inner surface of the air cleaner case 40 and on a support plate side hook 95 attached to the left rim portion of the element support plate 7. At that time, as referred to above, when the fixing pin 91 a of the element holder 91 is inserted forwardly from the rear side into the pin hole 73 provided in the element support plate 7, the cleaner element 9 is fixed in position (see FIG. 4). [0046] 15 In the air cleaner 4 as referred to above, intake air is inhaled from the inlet duct 48a to a dirty area 4a in a backward region of the cleaner element 9 within the cleaner case 40, as shown by a solid white arrow in the drawing. The intake air which passes forwardly through the cleaner element 9 and is clarified enters a clean area 4b in a forward region of the cleaner element 9. The intake air passing forwardly through the element guard 74 (see FIGS. 5 and 9) of the air intake opening 7a of the element support plate 7 from the inner space 90 (see FIG. 5) of the cleaner element 9 passes through the air intake passage 74 of the connecting tube 6 and is delivered via the carburetor 36 to the internal combustion engine 1. [0047] On the other hand, the blow-by gas passes through the breather tube 63 (see FIGS. 3 and 4) from the crankcase 10 of the internal combustion engine 1 and is delivered via the blow-by gas return joint 62a into the breather return chamber 62, as shown by a solid black arrow in the drawing. Although the partition wall 61 which separates the breather return chamber 62 from the air intake passage 60 of the connecting tube 6 forms a ceiling wall of the breather return chamber 62, a communicating passage 67 (see FIG. 11) for allowing the breather return chamber 62 to communicate with the air intake passage 60 is provided so that the blow-by gas is inhaled upwardly into the air intake passage 60 from the breather return chamber 62. The inhaled blow-by gas is delivered to the internal combustion engine 1 together with the intake air and burned there. Since the communicating passage 67 extends in the upward direction, a liquid component such as oil or the like mixed in the blow-by gas is hardly inhaled, whereby the communicating passage 67 also functions as a gas-liquid separation passage. [0048] Further, as referred to later in detail with reference to FIG. 9, in a portion of the element support plate 62 separating a rear part of the breather return chamber 62, there are provided blow-by gas passing holes 75 (a gas-liquid separating passage in the present invention). In a portion of the element support plate 7 located above the blow-by gas passing holes 75 and face to 16 face with the air intake passage 60, there is provided a blow-by gas return hole 76. The blow-by gas having once entered the interior of the air cleaner case 40 from the blow-by gas passing hole 75 is separated liquid from gas in such a manner that the contained liquid component such as a lubricating oil or the like (shown by a solid black arrow in FIGS. 6 and 9) is separated in the lower direction and the gas component is inhaled into the air intake passage 60 from the blow-by gas return hole 76 (a gas-liquid separating passage in the present invention) located above. The liquid component having streamed down to the lower part of the air cleaner case 40 flows into and is stored in the drain discharge pipe 52 and is discharged when the drain cap 52a is removed. [0049] In the connecting area between the connecting tube 6 and the air cleaner case 4, as shown in FIG. 4, the inner peripheral rim 45a of the front opening 45 of the air cleaner case 40 is fitted into the engaging groove 66 of the outer lateral surface of the flange portion 65 of the connecting tube 6. The fastening bolts 71 fixed on the element support plate 7 are inserted from the interior of the air cleaner case 40 into the fastening holes 65a of the connecting tube 6 and the fastening holes 50a of the air cleaner case which are fitted together, and further inserted into the fastening holes 55a of the holder plate 55. Thereafter, the fastening nuts 72 are screwed on the fastening bolts 71 from the front side, whereby the connecting tube 6 and the engaging section 49 of the air cleaner case 40 are tightened and fixed each other. Then, the connecting tube 6 and the engaging section 49 of the air cleaner case 40 are bonded and fixed in an air-tight fashion. [0050] Further, as shown in FIG. 6, in the closed condition of the left lateral opening 46 with the opening lid portion 47 fitted thereon, the peripheral rim portion 46a on the front rim side of the left lateral opening 46 is fitted to and fixed on the engaging groove 47a provided on the peripheral rim portion of the opening lid portion 47, in a state of placing the opening lid seal 47b between the peripheral rim portion 46a and the engaging groove 47a (see 17 FIG. 5). In the position of the front buckle 51A shown in FIG. 7, the front buckle 51A supported by the rotation support member 55b provided on the left rim portion of the holder plate 55 is rotated and pressed into contact with the peripheral rim portion of the opening lid portion 47 in the vehicle center direction, namely in the right direction, whereby to fix the opening lid portion 47 in the detachable fashion. Similarly, the rear buckle 51B fixes the opening lid portion 47 in the detachable fashion. [0051] Further, the element guard 74 of wire mesh shape is welded and secured in a backwardly swelling form in multiple layers to a rear surface side of the air intake opening 7a of the element support plate 7 (see FIGS. 5 and 9), whereby to prevent fly substances from entering the interior of the element opening 9a (see FIG. 5) of the cleaner element 9 and from being inhaled together with the intake air into the internal combustion engine 1. [0052] FIG. 7 is a rear view of the air cleaner 4 taken in the direction of arrows VII-VII in FIG. 6, showing the battery housing section 43, the positions of the left and right battery band hooks 44L, 44R, the positions of the opening lid portion 47 and the rear buckle 51B. The battery housing section 43 is arranged at a level in order to hold a battery electrolyte thereon. [0053] The holder plate 55 is provided with six fastening holes 55a (see FIG. 5) and two rotation support members 55b (see FIG. 6) for the front buckle 51A. The air intake passage 60 part and the breather return chamber 62 part of the connecting tube 6 are configured to pass through a central opening 55c of the holder plate 55 (see FIG. 5). [0054] FIG. 8 shows the connecting tube 6, in which (a) is a left side view thereof, and (b) is a rear end view thereof taken in the direction of arrows b-b in (a). The connecting tube 6 is formed with the backwardly concaved recess portion 6a between the upper part and the lower part thereof in a side view. 18 Across the recess portion 6a, the air intake passage 60 connected to the carburetor 36 is formed in the interior of the upper part. The rear end (the upstream end) 60a of the air intake passage 60 is connected to the inner space 90 of the cleaner element 9, namely, the clean area 4b of the air cleaner 4 through the front opening 45 and the air intake opening 7a of the element support plate 7 at the upward position of the air cleaner case 40. The front end 60b of the air intake passage 60 forms a connecting portion to the carburetor 36 to be connected to the carburetor 36. [0055] The partition wall 61 for separating the air intake passage 60 is formed in the interior of the recess portion 6a of the air intake passage 60 of the connecting tube 6. The breather return chamber 62 for receiving the blow-by gas from the internal combustion engine 1 is formed between the connecting tube 6 and the element support plate 7 (see FIGS. 5 and 9). The breather return chamber 62 is provided at the front side thereof with the blow-by gas return joint 62a and communicates through the breather tube 63 with the crankcase 10 (see FIG. 4). [0056] Although the rear side of the breather return chamber 62 is closed by the element support plate 7, in the element support plate 7 there are provided the blow-by gas passing hole 75 and the blow-by gas return hole 76 as the gas-liquid separation passage in the present invention to be referred to later (see FIG. 9). In addition, the partition wall 61 is provided with the communicating passage 67 communicating between the air intake passage 60 and the breather return chamber 62, so that the blow-by gas is inhaled upwardly from the breather return chamber 62 into the air intake passage 60. The flange portion 65 is formed around the periphery of the air intake passage 60 and the breather return chamber 62, and the engaging groove 66 is provided around the outer periphery of the flange portion 65. Also on the flange portion there are provided the plurality of (six in this embodiment) fastening holes 65a. 19 [0057] As shown in FIG. 5, in the front wall 50 of the air cleaner case 40 there are provided the front opening 45 and the fastening holes 50a around the perimeter of the front opening 45. The inner peripheral rim 45a of the front opening 45 is engaged into the engaging groove 66 (see FIG. 8) of the flange portion 65 of the connecting tube 6 whereby to be connected to the connecting tube 6. Each of the air intake passage 60 and the breather return chamber 62 of the connecting tube 6 fitted to the front opening 45 from the front side is opened backwardly to the interior of the air cleaner case 40. [0058] Although the air intake passage 60 and the breather return chamber 62 of the connecting tube 6 fitted to the air cleaner case 40 are opened to the interior of the air cleaner case 40 in the backward direction, respectively, the element support plate 7 fastened to the rear end of the flange portion 65 of the connecting tube 6 is provided with the air intake opening 7a which communicates only with the air intake passage 60, as shown in FIG.. 9. On the other hand, the element support plate 7 is configured to close the breather return chamber 62. [0059] The fastening bolts 71 are secured by welding to the periphery of the element support plate 7and extend in the forward direction. Screw portions 71a of the fastening bolts 71 project forwardly. In this embodiment, six fastening bolts 71 are secured by welding. Moreover, the multi-layered wire mesh-shaped element guard 74 is welded in a backwardly swelling form to the rear surface side of the air intake opening 7a. When the cleaner element 9 is pressed into contact with the rear surface of the element support plate 7, the element guard 74 enters and is positioned within the inner space 90 through the element opening 9a of the cleaner element 9 (see FIGS. 5 and 6), whereby to prevent foreign substances from being mixed into the intake air which has passed through the cleaner element 9. [0060] 20 FIG. 9 is a rear view of the element support plate 7. As shown in FIG. 9, the pin holes 73 into which the fixing pins 91a of the element holder 91 are inserted are provided on the upper central portion and the left (right side in the drawing) lower portion of the air intake opening 7a of the element support plate 7. When the cleaner element 9 together with the element holder 91 fitted thereinto is pressed from the rear side into contact with the element support plate 7 by the presser metal fitting 93 (see FIG. 6), the pressed part of the cleaner element 9 is partially compressed, and the fixing pins 91a freely pass through the pin holes 73. Then, the element holder 91 and the position of the element holder 91 in the plane direction of the element support plate 7 are restrained by the two fixing pins 91a. [0061] Further, three blow-by gas passing holes 75 are provided in the portion of the element support plate 7 corresponding to the lower portion of the breather return chamber 62, and one blow-by gas return hole 76 is provided in the portion of the element support plate 7 corresponding to the lower portion of the air intake passage 60. with respect to the blow-by gas passing holes 75, the blow-by gas passes from the breather return chamber 62 defined on the front side, to the rear side, and with respect to the blow-by gas return hole 76, the blow-by gas passes from the rear side to the air intake passage 60 located on the front side. To the left rim portion (left side in the drawing) of the element support plate 7, the support plate side hook 95 of the presser metal fitting 93 is attached. [0062] FIG. 9 is a rear view of the element support plate 7, in which the connecting tube 6 abutting and fastened on the front side of the element support plate 7 is overlapped and illustrated by a dotted line. On the rear side of the element support plate 7, the multi-layered wire mesh-shaped element guard 74 is welded to the peripheral rim of the air intake opening 7a. On the periphery of the element support plate 7 there are shown heads 71b of the six fastening bolts 71 which are secured by welding in the forward direction. [0063] 21 Although the cleaner element 9 into which the element holder 91 is inserted and fitted (see FIG. 5) is pressed from the rear side to the rear surface of the element support plate 7 so as to cover substantially the whole area of the rear surface of the element support plate 7, grease is applied to a grease application area 77 shown by hatching in FIG. 9, between the element support plate 7 and a contact surface 9c (see FIG. 5) of the cleaner element 9, so that the direct gas circulation is prevented between an outer peripheral area and an inner peripheral area of the grease application area 77. Namely, the outer peripheral area is the outside (the upstream side) of the cleaner element 9 and communicates with the dirty area 4a (see FIG. 6) within the air cleaner case 40, while the inner peripheral area is the inside (the downstream side) of the cleaner element 9 and communicates with the clean area 4b within the air cleaner case 40. Accordingly, the direct circulation of the intake air from the dirty area 4a to the clean area 4b is prevented by the grease application area 77 to which the grease is applied. [0064] Although on the rear side of the element support plate 7, the blow-by gas in the breather return chamber 62 flows in from the blow-by gas passing holes 75 corresponding to the lower portion of the breather return chamber 62, the blow-by gas passing holes 75 are located on the inside of the support plate peripheral area 77 and in the clean area 4b, as shown in the drawing. On the other hand, the blow-by gas return passage 76 provided above the blow-by gas passing holes 75 in the portion of the element support plate 7 corresponding to the lower portion of the air intake passage 60 is also located in the clean area 4b. Accordingly, the blow-by gas flowing into the rear side of the element support plate 7 from the blow-by gas passing holes 75 is absorbed in the clean area 4b into the intake air which circulates from the air intake opening 7a of the element support plate 7 to the air intake passage 60 of the connecting tube 6, without being mixed with the intake air in the dirty area 4a, and flows into the air intake passage 60 from the blow-by gas return hole 76, so that, together with the intake air, it is delivered via the carburetor 36 to the internal combustion engine I to be burned. 22 [0065] Then, the contained liquid component (shown by the solid black arrow in FIG. 9) of the blow-by gas having once entered the interior of the air cleaner case 40 from the blow-by gas passing hole 75 is separated in the lower direction to pass through the lower portion of the cleaner element 9 and streams down to the lower portion of the air cleaner case 40, while the gas component is inhaled into the air intake passage 60 from the blow-by gas return hole 76. Therefore, the gas-liquid separation is efficiently performed whereby it is possible to decrease the influence of the liquid component of the blow-by gas upon the internal combustion engine 1. As shown by the solid black line in FIG. 6, the liquid component of the blow-by gas having streamed down to the lower portion of the air cleaner case 40 flows into the drain discharge pipe 52 to be stored therein and is discharged when the drain cap 52a is removed. [0066] Namely, the blow-by passing hole75 and the blow-by return hole 76 provided in the element support plate 7 together with the communicating passage 67 provided in the partition wall 61 of the connecting tube 6, have efficient gas-liquid separation passages so formed as to be connected to the air intake passage 60 of the connecting tube 6 in the upward direction from the breather return chamber 62. [0067] By the way, in the inner space 90 of the cleaner element 9, there is inserted and fitted the element holder 91 which prevents the cleaner element 9 from being compressed by the intake air and which allows the cleaner element 9 to be mounted in the predetermined position. The element holder 91 is formed in a basket-shaped frame and includes the prop 91b which extends backwardly from the center of the element holder 91, a peripheral frame 91c which forms the periphery of the element holder 91, and the fixing pins 91a (see FIG. 5) which project forwardly from the peripheral frame 91c. [0068] As shown in FIG. 5, the cleaner element 9 is made of materials such as 23 a sponge, mesh or non-woven fabric, and includes a back member 9d of a plate form which swells backwardly in an arch-shaped cross section, a side member 9e covering an arch-shaped lateral side, and a flat bottom member 9f closing the front side. These three members are bonded together so as to form a vault shaped box having the inner space 90. [0069] The bottom member 9f is provided at a center thereof with the element opening 9a and at an upper central portion and a lower left portion (lower right side in the drawing) thereof with the pin holes 9b into which the fixing pins 91a of the element holder 9 are inserted. [0070] The element holder 91 is inserted and fitted into the inner space 90 of the cleaner element 9, the fixing pins 91a of the element holder 91 are inserted from the pin holes 9b and project in the forward direction, and the prop 91 b of the element holder 91 is inserted from a top hole 9g and projects in the backward direction. In this state, the cleaner element 9 is inserted from the left lateral opening 46 of the air cleaner case 40, and fixed in position by allowing the fixing pins 91a of the element holder 91 to pass through the pin holes 73 of the already fixed element support plate 7. Next, when the presser metal fitting 93 is engaged with the top portion of the prop 91 b of the element holder 91 and the presser metal fitting 93 is hooked on the case side hook 94 and the support plate side hook 95, the cleaner element 9 contacts under pressure the element support plate 7 in the predetermined position. The disassembly is performed in reverse order. [0071] As shown in FIG. 6, in the air cleaner case 40, the presser metal fitting 93 each end of which is mounted on the case side hook 94 provided in the right inside of the air cleaner case 40 and on the support plate side hook 95 provided on the left rim portion of the element support plate 7 is engaged with the top portion of the prop 91b of the element holder 91 which projects from the rear central portion of the cleaner element 9, whereby to allow the cleaner element 9 to be pressed through the element holder 91 into contact 24 with the element support plate 7 in the forward direction. The position of the cleaner element 9 on the planar surface of the element support plate 7 is determined by the pin hole 73 of the element support plate 7 and the fixing pin 91a of the element holder 91, while the position in the forward and backward direction of the cleaner element 9 is determined by the level where the peripheral frame 91c of the element holder 90 compresses the bottom member 9f of the cleaner element 9 in the pressing direction against the element support plate 7. [0072] The characteristics of the air cleaner structure of the straddle type vehicle according to this embodiment will be summarized hereunder. Namely, the air cleaner case structure in a straddle type vehicle which has the internal combustion engine 1, the air cleaner case 40 arranged in the rear of the internal combustion engine 1, and the rider's seat 33 covering the internal combustion engine 1 and the air cleaner case 40 from above, comprises the connecting tube 6 which extends toward the internal combustion engine 1, being provided on the front side of the air cleaner case 40, the space for the exhaust pipe 37 being provided on the right lateral side of the air cleaner case 40, the opening lid portion 47 for performing maintenance of the cleaner element 9 within the air cleaner case 40, being provided on the left side of the air cleaner case 40, the battery housing section 43 for accommodating the battery 8 for supplying ignition energy to the internal combustion engine 1, being extended in the rear part of the air cleaner case 40, and the air intake port 48 being arranged on the upper portion of the air cleaner case 40. [0073] Therefore, since the battery 8 is supported on the rear part of the air cleaner case 40, the maintenance of the battery 8 can be easily performed by setting the rider's seat 33 upright, and the air intake system can be effectively arranged without interference with the battery 8. In addition, since the exhaust pipe 37 and the opening lid portion 47 of the air cleaner case 40 are arranged on the opposite sides in the vehicle width direction of the air cleaner 25 case 40, the layout of the exhaust pipe 37 can be optimized, so that the increase of the width of the vehicle body in the vehicle width direction can be restrained, and the maintenance of the air intake system such as the cleaner element 9 or the like can be performed without obstruction by the exhaust pipe 37 or the like, whereby to improve the maintainability. [0074] Further, the rear cushion 31 is arranged between the internal combustion engine 1 and the air cleaner case 40 in the rear of the internal combustion engine 1.The connecting tube 6 is so formed as to make a detour in the vehicle width direction to avoid the rear cushion 31. The opening lid portion 47 is arranged on the same left lateral side of the vehicle as the connecting tube 6. Therefore, since the maintenance of the connecting tube 6 and the cleaner element 9 is able to be performed from the same direction, the maintenance time can be shortened whereby to further improve the maintainability. Particularly, in the race or the like, the shortening of the maintenance time is more important, so that it is effective. [0075] Further, the air intake passage 60 of the connecting tube 6 is connected to the upward part of the air cleaner case 40, and the breather return chamber 62 for receiving blow-by gas from the internal combustion engine 1 is formed in the lower part of the connecting tube 6. Therefore, since the maintenance of a breather system such as the breather tube 63, the drain cap 52a of the drain discharge pipe 52 or the like is able to be performed in the same direction as the maintenance of the cleaner element 9, the maintainability can be further improved. [0076] Further, since the pair of left mounting boss 42L and right mounting bosses 42R are provided on the left and right sides of the battery housing section 43 of the rear part of the air cleaner case 40, the air cleaner case 40 is so formed as to be supported on the left and right sides of the battery housing section 43 of the rear part thereof, so that the heavy battery 8 can be efficiently carried on the air cleaner case 40 and the opening lid portion 47 26 can be made larger thereby improving the maintainability. [0077] Moreover, since the breather tube 63 extending from the internal combustion engine 1 so as to be connected to the breather return chamber 63 is plumbed in such a manner as to be bent in an S-shaped form in a plan view above the crankcase 10 of the internal combustion engine 1, the length of the breather tube 63 is ensured by being plumbed in a state of being bent in an S-shaped form, so that the mutual movement between the internal combustion engine 1 and the air cleaner case 40 can be absorbed, and the mixed oil flowing into the breather tube 63 due to a sharp inclination of the vehicle can be stored and restrained from flowing out. [0078] In addition, the breather return chamber 62 is formed between the recess portion 6a of the connecting tube 6 and the element support plate 7 for supporting the cleaner element 9 and communicates with the upwardly located air intake passage 60 of the connecting tube 6 through the blow-by gas passing hole 95 and the blow-by gas return hole 76 as the gas-liquid separation passages provided in the element support plate 7. Therefore, the gas-liquid separation structure is simplified, and the blow-by gas passing hole 75 and the blow-by gas return hole 76 through which the blow-by gas flows are connected in the upward direction to the air intake passage 60 of the connecting tube 6, so that the gas-liquid separation can be efficiently performed and the influence of the blow-by gas upon the internal combustion engine 1 can be decreased. [0079] While the air cleaner case structure of the straddle type vehicle according to the present invention has been described with reference to its preferred embodiment, it is to be understood that the present invention is not limited to the above described embodiment, and that various changes and modifications may be made without departing from the scope of the present invention. For example, the straddle type vehicle is not limited to the two wheeled 27 motorcycle of the present embodiment but includes small three-wheeled or four-wheeled buggies, etc., and with respect to the internal combustion engine, number of cylinder does not constitute a matter of concern. In addition, although the description is limited, for the sake of explanation, to such specific left and right arrangement as illustrated in the drawings, the present invention may also be applied to the case where the internal combustion engine, the air cleaner, etc. are arranged to face in the opposite direction to the illustrated arrangement. DESCRIPTION OF REFERENCE CHARACTERS [0080] 1 ... Internal combustion engine, 2 ... Two-wheeled motorcycle (as straddle type vehicle of the present invention, 4 ... Air cleaner, 6 ... Connecting tube, 6a ... Recess portion, 7 ... Element support plate (as support plate of the present invention), 7a ... Air intake opening, 8 ... Battery, 9 ... Cleaner element, 9a ... Element opening, 9b ... Pin hole, 20 ... Vehicle body frame, 22 ... Main frame, 22a ... Steeply inclined portion, 25 ... Back stay, 31 ... Rear cushion, 33 ... Rider's seat, 35 ... Inlet pipe, 36 ... Carburetor, 37 ... Exhaust pipe, 38 ... Silencer, 40 ... Air cleaner case, 40a ... Recess, 42L ... Left mounting boss (as a pair of vehicle body mounting bosses in the present invention), 42R ... Right mounting boss (as a pair of vehicle body mounting bosses in the present invention), 43 ... Battery housing section, 45 ... Front opening, 47 ... Opening lid portion, 48 ... Air intake port, 50 ... Front wall, 50a ... Fastening hole, 52 ... Drain discharge pipe, 52a ... Drain cap, 55 ... Holder plate, 55a ... Fastening hole, 60 ... Air intake passage, 61 ... Partition wall, 62 ... Breather return chamber, 62a ... Blow-by gas return joint, 63 ... Breather tube, 64 ... L-shaped joint, 65 ... Flange portion, 65a ... Fastening hole, 67 ... Communicating passage, 71 ... Fastening bolt, 72 ... Fastening nut, 73 ... Pin hole, 75 ... Blow-by gas passing hole (as gas-liquid separation passage in the present invention), 76 ... Blow-by gas return hole (as gas-liquid separation passage in the present invention), 77 ... Grease application area, 80 ... Battery holding band, 91 ... Element holder, 91a ... 28 Fixing pin, 91b ... Prop, 93 ... Presser metal fitting, 94 ... Case side hook, 95 ... Support plate side hook 29

Claims (6)

1. An air cleaner case structure for a straddle type vehicle which has an internal combustion engine, an air cleaner case arranged in the rear of the internal combustion engine, and a rider's seat covering these internal combustion engine and air cleaner case from above, comprising: a connecting tube which extends to the internal combustion engine, being provided on a front side of the air cleaner case; a space for an exhaust pipe being provided on one lateral side of left and right sides of the air cleaner case; an opening lid portion for performing maintenance of a cleaner element within the air cleaner case, being provided on the other of the left and right sides of the air cleaner case; an air intake port being arranged on an upper portion of the air cleaner case; and a battery housing section for accommodating a battery for supplying ignition energy to the internal combustion engine, being extended in a rear part of the air cleaner case.

2. An air cleaner case structure for a straddle type vehicle according to claim 1, further comprising a rear cushion being arranged between the internal combustion engine and the air cleaner case in the rear of the internal combustion engine, wherein the connecting tube is so formed as to make a detour in the vehicle width direction to avoid the rear cushion, and the opening lid portion is arranged on the same lateral side of the vehicle as the connecting tube.

3. An air cleaner case structure for a straddle type vehicle according to claim 2, wherein an air intake passage of the connecting tube is connected to an upward part of the air cleaner case, and a breather return chamber for receiving blow-by gas from the internal combustion engine is formed in a lower part of the connecting tube.

4. An air cleaner case structure for a straddle type vehicle according to any one of claims I through 3, further comprising a pair of mounting bosses being provided on a left and right sides of the battery housing section of the rear part of the air cleaner case.

5. An air cleaner case structure for a straddle type vehicle according to claim 3, further comprising a breather tube extending from the internal combustion engine to be connected to the breather return chamber, wherein the breather tube is plumbed in a state of being bent in substantially an S-shaped form in a plan view above a crankcase of the internal combustion engine. 31

6. An air cleaner case structure for a straddle type vehicle according to claim 3 or claim 5, wherein the breather return chamber is formed between a recess portion of the connecting tube and a support plate of the cleaner element and communicates with the upwardly located air intake passage of the connecting tube through a gas-liquid separation passage provided in the support plate. Honda Motor Co., Ltd. Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON