JP4270954B2 - Motorcycle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionSuckA cylinder head provided with an air port; a throttle body in which a throttle valve capable of controlling the flow area of the intake passage is disposed in a body having an intake passage communicating with the intake port; Fuel injection type engine comprising a fuel injection valve for injecting fuel towardMotorcycle equipped withRelated to improvements.In the present specification, front / rear / left / right refers to front / rear / left / right with respect to the motorcycle body.
[0002]
[Prior art]
  A fuel injection type engine in which a fuel injection valve for injecting fuel toward an intake port of a cylinder head is attached to the cylinder head is known, for example, in Patent Document 1 or the like.
[0003]
[Patent Document 1]
  Japanese Patent Laid-Open No. 11-245894
[0004]
[Problems to be solved by the invention]
  By the way, in the above conventional one, a throttle body is connected to the intake port of the cylinder head via an intake manifold, and the intake manifold is bent so as to face upward in the vicinity of the connection portion to the intake port. Therefore, the fuel injection valve is attached to the cylinder head so that most of the fuel injection valve is buried in the cylinder head in order to avoid interference with the intake manifold. For this reason, heat from the combustion chamber is easily transmitted to the fuel injection valve, and it is necessary to take measures against heat resistance of the fuel injection valve. The throttle body must be disposed at a position relatively away from the cylinder head, and includes the throttle body. It is difficult to downsize the entire engine.
[0005]
  The present invention has been made in view of such circumstances, and a fuel injection type engine that enables a throttle body to be disposed close to a cylinder head and can effectively cool a fuel injection valve.Motorcycle equipped withThe purpose is to provide.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, the invention according to claim 1Left and right main frames extending downward from the head pipe, down tubes extending downward from front portions of the main frames, left and right center frames integrally extending to the rear ends of the left and right main frames, and left and right A motorcycle in which a fuel injection engine is supported by a vehicle body frame having a cross member connecting between rear portions of the main frame, and an upper end portion of a rear cushion is attached to a center portion in the vehicle width direction of the cross member, EngineA cylinder head provided with an intake port; a throttle body in which a throttle valve capable of controlling the flow area of the intake passage is disposed in a body having an intake passage communicating with the intake port; Fuel injection valve that injects fuel towardIn what consists of
The cylinder head is more than the connecting portion of the cylinder head and the head cover.Rear sideTo the inlet port of the intake portBackwardsThe connecting cylinder portion to be formed is integrally provided so that the axis of the inlet portion is disposed in a plane substantially orthogonal to the cylinder axis, and is attached to the cylinder head so as to inject fuel toward the intake port. A mounting hole for liquid-tightly fitting the tip of the fuel injection valve is provided in the connecting cylinder, and the throttle body isIn front of the cross member and between the left and right main frames, the throttle bodyThe intake passage axis is connected to the connecting tube portion via an insulator so that the intake passage axis is arranged on the plane.The left and right main frames are formed such that the mutual interval between the portions sandwiching the throttle body of both main frames increases as the cross member approaches, and a seat is provided above the main frames on the throttle. The insulator and the insulator are arranged so as to cover from above, and the insulator is formed to bend in one side in the left-right direction within the plane, and the intake passage axis line of the throttle body connected to the insulator is rearward in plan view The throttle valve is integrally inclined with the throttle valve between the side surface of the throttle body on the other side in the left-right direction and the main frame on the other side in the left-right direction. A rotating throttle drum is arranged, and the intake passage of the throttle body An intake passage disposed between the flow end and an air cleaner disposed behind the throttle body and supported by the vehicle body frame so as to bypass the side of the rear cushion on one side of the rear cushion in the left-right direction. Connected throughIt is characterized by that.
[0007]
  According to such a configuration of the first aspect of the invention, the throttle body can be exposed to the outside of the cylinder head while the throttle body is close to the cylinder head, and the throttle body is included. The fuel injection valve can be effectively cooled while the entire engine can be downsized.Further, since the insulator is bent, the throttle body can be brought closer to the cylinder head side.
[0008]
  In addition to the configuration of the invention described in claim 1, the invention described in claim 2A throttle wire wound around the throttle drum extends rearwardAccording to such a configuration,, SuThe fuel injection valve does not get in the way of arranging the throttle wire wound around the lottle drum.
[0009]
    The invention according to claim 3 is the above claim 1.Or 2In addition to the configuration of the invention described above, the cylinder head includes an intake valve such that the operation axis intersects in a substantially V shape on a projection view on a plane including the cylinder axis and the axis of the inlet port of the intake port. And a valve operating device having a camshaft disposed between the intake valve and the exhaust valve with an axis substantially parallel to an axis of the inlet portion of the intake port, It is accommodated in a valve operating chamber formed between a cylinder head and a head cover coupled to the cylinder head. According to such a configuration, the width of the upper portion of the cylinder head is made as small as possible, thereby The number of protrusions from the cylinder head of the fuel injection valve can be increased to cool the fuel injection valve more effectively.
[0010]
  Furthermore, the invention of claim 4 is the above claim.1 to 3In addition to the structure of the described invention,The engine isBetween the mainframes,in frontWith throttle bodyThe fuel injector andThe cylinder head is arranged to be a single cylinder, and according to such a configuration,SelfThe fuel injection valve and the throttle body can be arranged while narrowing the interval between the left and right main frames provided in the motorcycle, which can contribute to the improvement of the rider's straddle and ride comfort.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.
[0012]
  1 to 8 show an embodiment of the present invention, FIG. 1 is a side view of a small motorcycle, and FIG. 2 is a view from the direction of arrow 2 in FIG. 1, omitting a fuel tank and a riding seat. 3 is a cross-sectional view taken along line 4-4 of FIG. 3, FIG. 5 is a top vertical side view of the engine, and FIG. 6 is a view of arrow 6 in FIG. 5 with the head cover omitted. FIG. 7 is a sectional view taken along line 7-7 in FIG. 6, and FIG. 8 is a bottom view of the main part of the cylinder head taken along line 8-8 in FIG.
[0013]
  1 and 2, a body frame 11 of a small motorcycle used in a trial competition includes a head pipe 12, a pair of left and right main frames 13, 13 extending rearwardly downward from the head pipe 12, and their main frames. 13... A pair of left and right down tubes 14 extending downward from the front portions of the respective main frames 13, a pair of left and right center frames 15 integrally extending to the rear ends of the main frames 13, and the main frames 13. An intermediate cross member 16 that connects the intermediate portions of the two main frames 13, a rear cross member 17 that connects the rear portions of the main frames 13, and a lower cross member 18 that connects the lower portions of the center frames 15. Is provided.
[0014]
  The front fork 19 that supports the front wheel WF is supported by the head pipe 12 at the front end of the vehicle body frame 11 so as to be steerable. A bar-shaped steering handle 20 is connected to the front fork 19. Further, the front end portion of the rear fork 21 that pivotally supports the rear wheel WR at the rear end portion is attached to the pair of left and right center frames 15... A link mechanism 23 is provided between the lower cross member 18 and the rear fork 21, and a rear cushion 24 is provided between the link mechanism 23 and the rear cross member 17.
[0015]
  A fuel tank 25 is mounted between the front portions of the pair of left and right main frames 13. A riding seat 26 disposed behind the fuel tank 25 is supported by the intermediate cross member 16 and the rear cross member 17. A rear fender 27 is connected to the rear end of the riding seat 26.
[0016]
  Between the front wheel WF and the rear wheel WR, a power unit P including a water-cooled and fuel-injected engine E, which is a single-cylinder four-cycle engine, and a constantly meshing transmission M is disposed. The engine body 30 of the engine E is supported by a hanger plate 28 and a lower cross member 18 that hang downward from the lower ends of the pair of left and right down tubes 14. A skid plate 29 is disposed below the engine main body 30 with a gap between the engine main body 30 and the lower portion of the engine main body 30. The skid plate 29 includes a lower end portion of the down tube 14 and a lower cross member. 18 is attached.
[0017]
  3 to 5, the engine body 30 of the engine E includes a crankcase 31, a cylinder block 32 coupled to the crankcase 31, a cylinder head 33 coupled to the cylinder block 32, and a cylinder head 33. And a head cover 34 coupled to the head.
[0018]
  A crankcase 31 that rotatably supports the crankshaft 36 includes a right case half 37 that is disposed on the right side when mounted on a motorcycle, and a left case half 38 that is disposed on the left side when mounted on a motorcycle. Are joined together at a mating surface 39 along a plane perpendicular to the axis of the crankshaft 36. In addition, a crank chamber 40 that houses the main part of the crankshaft 36 and a transmission chamber 41 that houses the transmission M are formed in the crankcases 31.
[0019]
  A main portion of the crankshaft 36 is accommodated in the crank chamber 40, and a large end portion of a connecting rod 45 connected to a piston 44 slidably fitted in a cylinder bore 43 provided in the cylinder block 32 is The crankshaft 36 is connected via a crankpin 46.
[0020]
  One end of the crankshaft 36 passes through the right case half 37 rotatably, and the other end of the crankshaft 36 passes through the left case half 38 rotatably. Thus, a ball bearing 47 is interposed between the right case half 37 and the crankshaft 36, and a roller bearing 48 is interposed between the left case half 38 and the crankshaft 36.
[0021]
  The transmission M has a main shaft 52 having an axis parallel to the crankshaft 36 and rotatably supported on the right and left case halves 37 and 38 via ball bearings 51, respectively, and the main shaft. And a countershaft 53 rotatably supported on both case halves 37, 38 via ball bearings 54, having an axis parallel to the main body 52, and the main shaft 52 includes a plurality of gear stages of driving gears. 55 are mounted, and the countershaft 53 is mounted with a driven gear group 56 corresponding to the drive gear group 55. Thus, by selectively establishing gears corresponding to each other among the drive gear group 55... And the driven gear group 56..., The output of the engine E is shifted to a plurality of stages and transmitted to the counter shaft 53. .
[0022]
  In FIG. 1 again, a drive sprocket 57 is fixed to the end of the counter shaft 53 protruding from the left case half 38 in front of the pivot shaft 22, and the driven sprocket 58 fixed to the rear wheel WR and the drive. An endless chain 59 is wound around the sprocket 57.
[0023]
  At one end of the main shaft 52 protruding from the right case half 37, a shift switching clutch 60 for switching power connection / disconnection between the crankshaft 36 and the main shaft 52 is mounted. The input member 61 provided is supported on the main shaft 52 so as to be relatively rotatable.
[0024]
  A power transmission gear train 62 is provided between the input member 61 of the shift switching clutch 60 and the crankshaft 36, and the power transmission gear train 62 is fixed to one end of the crankshaft 36. 63 and a clutch gear 64 that meshes with the first drive gear 63. The clutch gear 64 is connected to the input member 61 via a damper 65 and rotates together with the input member 61.
[0025]
  At one end of the crankshaft 36, a second drive gear 67 constituting a part of the power transmission gear train 66 for driving the auxiliary machine and the first drive gear 63 are brought into contact with each other by spline fitting or the like. The crankshaft 36 is mounted so as not to be relatively rotatable. The second drive gear 67 is integrally formed with a cylindrical portion 67a that is in contact with the outer surface of the inner ring of the ball bearing 47 interposed between the crankshaft 36 and the crankcase 31. A bolt 68 having a large-diameter head 68a that is in contact with and engages with the outer end of the first drive gear 63 is coaxially screwed to one end of the crankshaft 36.
[0026]
  That is, the cylindrical portion 67a of the second driving gear 67 is sandwiched between the first driving gear 63 and the ball bearing 47, and an annular oil seal 69 is interposed between the cylindrical portion 67a and the right case half 37. Is done.
[0027]
  The accessory drive power transmission gear train 66 is rotatably supported by the right case half 37 and the left case half 38 via a ball bearing 73 and a roller bearing 74 in front of the crankshaft 36. A first drive gear 67 fixed to the crankshaft 36 and a first driven gear fixed to one end of the balancer shaft 75 and meshing with the second drive gear 67. And a gear 76.
[0028]
  Above the balancer shaft 75, a water pump 80 is configured with a pump housing 79 including a right cover 77 coupled to the right case half 37 from the outside and a pump cover 78 fastened to the outer surface of the right cover 77. The water pump 80 includes a pump shaft 81 parallel to the balancer shaft 75.
[0029]
  The pump shaft 81 penetrates the right cover 77 of the pump housing 79 in a liquid-tight and rotatable manner, and a rotary blade 82 is coaxially fixed to one end portion of the pump shaft 81 that enters the pump housing 79. The other end of the pump shaft 81 is rotatably supported by the right case half 37.
[0030]
  A transmission gear train 83 is provided between one end portion of the balancer shaft 75 and the pump shaft 81, and the power transmitted from the crankshaft 36 to the balancer shaft 75 via the accessory drive power transmission gear train 66 is described above. It is transmitted to the pump shaft 81 via the transmission gear train 83.
[0031]
  The pump cover 78 in the pump housing 79 of the water pump 80 is provided with a water return pipe 84, which is disposed in front of the engine body 30 and is supported from the radiator 86 supported by the down tubes 14 of the vehicle body frame 11. A hose 85 (see FIG. 1) for guiding the water is connected to the return pipe 84. The water discharged from the water pump 80 is supplied via the crankcase 31 to the cooling jacket 87 provided in the cylinder block 32 and the cylinder head 33 in communication with each other.
[0032]
  The oil accumulated in the crankcase 31 is pumped up by the oil pump 90, and the oil pump 90 includes an inner rotor 92 fixed to the inner end of the pump shaft 91 and an outer rotor meshing with the inner rotor 92. 93 and configured in a trochoidal manner.
[0033]
  The pump chamber 94 that accommodates the inner rotor 92 and the outer rotor 93 has a housing recess 95 provided in the left case half 38 facing the mating surface 39, and a right case half 37, and a right case half 37 and a left case. The mating surface 39 is sandwiched between the half bodies 38.
[0034]
  The pump shaft 91 is supported in a liquid-tight and rotatable manner by a support cylinder portion 96 provided in the right case half 38, and a second driven gear 97 is provided at an outer end portion of the pump shaft 91 protruding from the support cylinder portion 96. Is fixed. On the other hand, a third drive gear 98 is fixed to the other end portion of the balancer shaft 75, and the pump shaft 91 is rotationally driven when the third drive gear 98 meshes with the second driven gear 97.
[0035]
  At the portion facing the mating surface 39 of the right case half 37, a discharge-side recess 99 that leads to the pump chamber 94 and a suction-side recess 100 that leads to the pump chamber 94 serve as the inner end of the pump shaft 91. It is provided so as to be received by the right case half 37 between both concave portions 99 and 100.
[0036]
  On the other hand, the left case half 38 is provided with an oil discharge passage 101 having one end opened to the mating surface 39 so as to communicate with the discharge side recess 99 so as to supply oil to each lubricating portion of the engine. .
[0037]
  The suction side recess 100 and the lower part of the crankcase 31 are connected by an oil suction passage 102, and the oil suction passage 102 is formed between the right and left case halves 37, 38 sandwiching the mating surface 39. A passage groove 103 is provided in at least one of the case halves 37, 38, in this embodiment the left case halves 38.
[0038]
  A starting operation force corresponding to a kick operation can be input to the clutch gear 64 via the kick start gear train 105, and the kick start gear train 105 is attached to a kick shaft 106 that is rotatably supported by the crankcase 31. The fourth drive gear 107, the idle gear 108 fixed to the counter shaft 53 and meshing with the fourth drive gear 107, and the third drive gear supported relative to the main shaft 52 and meshed with the idle gear 108. The input member 61 of the shift switching clutch 60 is mounted on the third driven gear 109 so as not to be relatively rotatable.
[0039]
  The fourth drive gear 107 is supported by the kick shaft 106 so as to be rotatable and not relatively movable in the axial direction, and between the kick shaft 106 and the fourth drive gear 107, between the two 106, 107 during the forward rotation of the kick shaft 106. A one-way clutch mechanism 110 to be connected is provided.
[0040]
  The one-way clutch mechanism 110 includes a clutch body 111 that can be axially moved relative to the kick shaft 106 and cannot be relatively rotated, and a friction spring 112 that applies a frictional resistance to the rotation of the clutch body 111. Ratchet teeth 113 and 114 for transmitting only forward rotation of the clutch body 111, that is, the kick shaft 106 to the fourth drive gear 107 at the time of meshing are provided on the opposing surfaces of the fourth drive gear 107 and the clutch body 111. It is formed.
[0041]
  Between the right case half 37 and the kick shaft 106, kick return springs 115, 115 made of torsion coil springs are arranged so as to be doubled inside and outside. By these kick return springs 115, 115, The kick shaft 106 is spring-biased to the return side.
[0042]
  With further reference to FIGS. 6 and 7, a combustion chamber 117 is formed between the cylinder block 32 and the cylinder head 33 so as to face the top of the piston 44, and the cylinder head 33 has an axis of the cylinder bore 43, that is, A plurality of (one pair in this embodiment) intake valves 118 such that the operating axes intersect in a substantially V shape on a projection view onto the first plane PL1 (a plane parallel to FIG. 5) including the cylinder axis C. And exhaust valves 119 are arranged so as to be openable and closable.
[0043]
  The cylinder head 33 has a pair of intake valve ports 120 facing the combustion chamber 117 so as to be opened and closed by the respective intake valves 118, and a rear side wall of the cylinder head 33 that is connected to both the intake valve ports 120 in common. And a pair of exhaust valve ports 122 facing the combustion chamber 117 so as to be opened and closed by the exhaust valves 119, and the exhaust valve ports 122, respectively. A single exhaust port 123 opening in the front side wall of the cylinder head 33 is provided.
[0044]
  In addition, a pair of intake side guide cylinders 124, in which the intake valves 118 are slidably fitted to the cylinder head 33 so as to guide the opening and closing operations of the intake valves 118, and exhaust valves 119,. Are provided with a pair of exhaust side guide cylinders 125 slidably fitted to both exhaust valves 119 so as to guide the opening and closing operation of the intake valves, and both intake valves protruding from the intake side guide cylinders 124 are provided. Valve springs 126 for urging the intake valves 118 in the valve closing direction are interposed between the upper ends of the 118 and the cylinder head 33, and the upper ends of the exhaust valves 119 projecting from the exhaust side guide cylinders 125, respectively. Valve springs 127 for biasing the exhaust valves 119 in the valve closing direction are interposed between the cylinder head 33 and the cylinder head 33, respectively.
[0045]
  On the rear side wall of the cylinder head 33, a connecting tube portion 138 that protrudes outward from the coupling portion of the cylinder head 33 and the head cover 34 to form the inlet portion 121a of the intake port 121 is connected to the axis of the inlet portion 121a. They are integrally provided so as to be arranged in a second plane PL2 substantially orthogonal to the cylinder axis C.
[0046]
  A throttle body 129 is connected to the connecting cylinder portion 138 via an insulator 128. Thus, the insulator 128 is formed by baking the flange 128b at the downstream end of the cylindrical portion 128a made of rubber, and the flange 128b is joined to the connecting cylindrical portion 138. A throttle body 129 connected to the upstream end of the insulator 128 is disposed on a body 131 having an intake passage 130 communicating with the intake port 121 so that a throttle valve 132 capable of controlling the flow area of the intake passage 130 can be opened and closed. It is set up.
[0047]
  Moreover, the cylindrical portion 128a of the insulator 128 is formed to bend in the second plane PL2, and the throttle body 129 has the intake passage 130 disposed on the second plane PL2 so that the insulator 128 is disposed. Is connected to the upstream end. The throttle body 129 is disposed outside the body 131 so as to rotate integrally with the throttle valve 132 and includes a throttle drum 133 that is wound around and connected to the throttle wire 134. The throttle body 129 is connected to the cylinder head 33 via the insulator 128 in such a posture that is disposed on the opposite side of the cylinder head 33.
[0048]
  By the way, a fuel injection valve 135 for injecting fuel toward the intake port 121 is attached to the cylinder head 33. The tip of the fuel injection valve 135 is liquid-tightly attached to the connecting cylinder portion 138 of the cylinder head 33. A mounting hole 136 that is fitted into the cylinder head 33 is provided, and a holder 137 that is fastened to the cylinder head 33 is fitted into the rear end portion of the fuel injection valve 135 that has its tip end fitted into the mounting hole 136 in a liquid-tight manner. . That is, the fuel injection valve 135 is attached to the cylinder head 33 so as to be sandwiched between the cylinder head 33 and the holder 137, and fuel is supplied from the holder 137 to the fuel injection valve 135.
[0049]
  By the way, the valve gear 140 that opens and closes the pair of intake valves 118... And the exhaust valves 119... Has an axis substantially parallel to the axis of the inlet 121 a of the intake port 121. A camshaft 141 disposed between the exhaust valves 119..., An intake-side rocker arm 142 that swings in response to the rotation of the camshaft 141 to open and close the intake valves 118, and the rotation of the camshaft 141. And an exhaust-side rocker arm 143 that swings and opens and closes both exhaust valves 119... And a valve-operating chamber 144 formed between the cylinder head 33 and the head cover 34 coupled to the cylinder head 33. Be contained.
[0050]
  Both end portions of the camshaft 141 are rotatably supported via ball bearings 145 and 146 between the coupling surfaces of the cylinder head 33 and the head cover 34, and one end portion of the camshaft 141 is attached to the crankshaft 36. Rotational power is transmitted through the timing transmission device 147.
[0051]
  The timing transmission device 147 is fixed to a drive sprocket 148 (see FIG. 4) formed integrally with a portion of the crankshaft 36 that protrudes from the left case half 38 of the crankcase 31, and one end of the camshaft 141. Driven sprocket 149, a driving sprocket 148 and a cam chain 150 wound around the driven sprocket 149, and between the crankcase 31 through the cylinder block 32 and the cylinder head 33, A chain chamber 151 for accommodating the cam chain 150 is formed.
[0052]
  On both sides of the camshaft 141, an intake side rocker shaft 152 and an exhaust side rocker shaft 153 are arranged with axes parallel to the camshaft 141, and both end portions of both the rocker shafts 152, 153 are cylinder heads. 33 is fixedly supported by being sandwiched between the head cover 34 and the head cover 34.
[0053]
  The intake-side rocker arm 142 is supported by an intake-side rocker shaft 152 so as to be swingable. The intake-side rocker arm 142 pivotally supports an intake-side cam 154 provided on the camshaft 141. .. Are integrally provided with arms 142b and 142c that abut the front end portion on the upper end portion. The exhaust-side rocker arm 143 is supported by the exhaust-side rocker shaft 153 so as to be swingable. The exhaust-side rocker arm 143 supports both the exhaust valve and an arm 143a that supports a roller 157 that is in rolling contact with the exhaust-side cam 155 provided on the camshaft 141. 119... Are integrally provided with arms 143 b and 143 c that abut the tip of the upper end of 119.
[0054]
  The camshaft 141 is biased toward the chain chamber 151 so that the other end, that is, the portion supported by the cylinder head 33 and the head cover 34 via the ball bearing 146 substantially corresponds to the central portion of the combustion chamber 117. Placed in position. Further, the peripheral wall of the valve operating chamber 144 is formed by valve operating chamber forming walls 33a and 34a provided in the cylinder head 33 and the head cover 34, and the camshaft 141 of the valve operating chamber forming walls 33a and 34a is formed. A recess 158 is formed in a portion corresponding to the other end.
[0055]
  On the other hand, a spark plug 159 having a front end facing the substantially central portion of the combustion chamber 117 and a rear end portion disposed in the recess 158 is inclined so that the rear end side is separated from the chain chamber 151. The cylinder head 33 is provided with a plug mounting hole 160 for mounting the spark plug 159.
[0056]
  By the way, the cylinder head 33 is provided with a cooling water outlet pipe portion 161 for leading cooling water from the cooling jacket 87, and the space between the cooling water outlet pipe portion 161 and the radiator 86 is connected via a hose 162 (see FIG. 1). Connected.
[0057]
  Moreover, the cooling water lead-out pipe portion 161 is arranged on the opposite side of the chain chamber 151 and outside the valve chamber forming walls 33a, 34a, and from the recess 158 to the intake valves 118 ... and the exhaust valves 119 ... It is provided in the cylinder head 33 so as to extend substantially parallel to the cylinder axis C at a position biased to either one side, in this embodiment, the exhaust valve 119.
[0058]
  Further, the angle α1 formed by the operating axis of the exhaust valve 119, which is closer to the cooling water outlet pipe portion 161 among the intake valves 118 and the exhaust valves 119, with the cylinder axis C on the projection onto the first plane PL1 is The operating axis of the intake valve 118, which is the other valve, is set smaller than the angle α2 formed with the cylinder axis C on the projection.
[0059]
  In addition, as shown in FIG. 8, the opening of the plug mounting hole 160 to the combustion chamber 117 is arranged to be deviated from the cylinder axis C toward the intake valve 118... Between the intake valve opening 120 provided in the cylinder head 33 facing the combustion chamber 117 and the exhaust valve opening 122 provided in the cylinder head 33 facing the combustion chamber 117 and the plug mounting It is set smaller than the distance between the openings of the holes 160.
[0060]
  In addition, the axis of the camshaft 141 in the valve operating device 140 is arranged in parallel to the camshaft 141 so as to deviate from the third plane PL3 including the cylinder axis C to the side opposite to the cooling water outlet pipe portion 161. ing.
[0061]
  The throttle body 129 is connected to an air cleaner 165 disposed behind the throttle body 129 and supported by the vehicle body frame 11. The cylinder head 33 of the engine E configured as an SOHC type as described above. The fuel injection valve 135 and the throttle body 129 are disposed between the pair of left and right main frames 13 and 13 included in the vehicle body frame 11.As shown in FIG. 2, the upstream end of the intake passage 130 of the throttle body 129 and the air cleaner 165 are arranged so as to bypass the side of the rear cushion 24 on one side in the left-right direction of the rear cushion 24. Connected through the intake passage ing.
[0062]
  An exhaust pipe 166 whose upstream end is connected to the exhaust port 123 of the cylinder head 33 extends rearward on the right side of the engine body 30 and is connected to the exhaust muffler 167 disposed on the upper right side of the rear wheel WR. Are connected at their downstream ends.
[0063]
  Next, the operation of this embodiment will be described. A pair of intake valves 118... And a pair of exhaust valves such that the operation axis intersects in a substantially V shape on the projection onto the first plane PL1 including the cylinder axis C. 119... Are arranged in the cylinder head 33 so as to be openable and closable, and the valve gear 140 for opening and closing the intake valves 118 and the exhaust valves 119 has an axis perpendicular to the first plane PL1. The camshaft 141 is disposed between the intake valves 118 and the exhaust valves 119, and receives rotational power from the crankshaft 36 via the timing transmission device 147 at one end. The camshaft 141 accommodates the cam chain 150 of the timing transmission device 147 in a steerable manner, with the other end substantially corresponding to the central portion of the combustion chamber 117. They are arranged in offset positions in En chamber 151 side. Moreover, of the valve chamber forming walls 33a and 34a provided on the cylinder head 33 and the head cover 34 so as to form a peripheral wall of the valve operating chamber 144 that accommodates the valve operating device 140, it corresponds to the other end portion of the camshaft 141. A concave portion 158 is formed in the portion, and a spark plug 159 having a rear end portion facing the substantially central portion of the combustion chamber 117 and having a rear end portion disposed in the concave portion 158 separates the rear end side from the chain chamber 151. It is attached to the cylinder head 33 with an inclination.
[0064]
  Therefore, the spark plug is formed in the recess 158 formed in the valve valve chamber forming walls 33a and 34a corresponding to the empty space generated by the deviation of the camshaft 141 toward the chain chamber 151 while avoiding interference with the valve valve chamber 144. 159 can be arranged.
[0065]
  Further, the cylinder head 33 is provided with a cooling water outlet pipe portion 161 for leading cooling water from the cooling jacket 87, but on the side opposite to the chain chamber 151, the valve chamber forming walls 33 a and 34 a The cooling water outlet pipe portion 161 disposed on the outer side and biased from the concave portion 158 toward one side of the intake valve 118... And the exhaust valve 119... In this embodiment, the exhaust valve 119. The cylinder head 33 is provided so as to extend substantially parallel to C.
[0066]
  Therefore, it is possible to reduce the size of the engine around the cylinder head 33 while ensuring the maintainability of the spark plug 159, and to provide the cylinder head 33 with the cooling water outlet pipe portion 161 extending substantially parallel to the cylinder axis C. Become.
[0067]
  In addition, an angle α1 formed by the operating axis of the exhaust valve 119, which is closer to the cooling water outlet pipe portion 161 among the intake valves 118 and the exhaust valves 119, with the cylinder axis C on the projection onto the first plane PL1 is: The operating axis of the intake valves 118 is set to be smaller than the angle α2 formed with the cylinder axis C on the projection, and the combustion chamber 117 of the plug mounting hole 160 provided in the cylinder head 33 for mounting the spark plug 159 is set. The opening to the cylinder is offset from the cylinder axis C toward the intake valve 118. That is, the distance between the opening of the plug mounting hole 160 to the combustion chamber 117 and the plurality of intake valve ports 120 provided in the cylinder head 33 facing the combustion chamber 117 so as to be opened and closed by the respective intake valves 118. The distance between the plurality of exhaust valve ports 122 provided in the cylinder head 33 facing the combustion chamber 117 and the openings of the plug mounting holes 160 is set to be opened and closed by the exhaust valves 119.
[0068]
  Therefore, the cooling passage area of the cooling jacket 87 is set to be relatively large between the valve shaft of the exhaust valve 119... And the spark plug 159 which is closer to the cooling water outlet pipe portion 161 among the intake valves 118. The cooling water is led out from the cooling jacket 87 on the side close to the exhaust valves 119..., So that the flow rate of the cooling water around the exhaust valves 119. The cooling performance of the cylinder head 33 can be improved.
[0069]
  Further, the axis of the camshaft 141 is arranged in parallel to the camshaft 141 and is offset from the third plane PL3 plane including the cylinder axis C to the side opposite to the cooling water outlet pipe portion 161. The angle formed by the operating axis of the exhaust valve 119, which is the valve closer to the outlet pipe 161, and the cylinder axis C can be set smaller to avoid interference with the camshaft 141. It is possible to further improve the cooling performance of the exhaust valves 119, which are valves closer to the outlet pipe portion 161.
[0070]
  Further, the cylinder head 33 has a connecting cylinder portion 138 that protrudes outward from the coupling portion of the cylinder head 33 and the head cover 34 to form the inlet portion 121a of the intake port 121, and the axis of the inlet portion 121a is the cylinder axis C. The tip of a fuel injection valve 135 that is integrally provided so as to be disposed in a second plane PL2 that is substantially orthogonal to the cylinder head 33 and that is attached to the cylinder head 33 so as to inject fuel toward the intake port 121 is liquid-tight. A fitting hole 136 to be fitted is provided in the connection cylinder portion 138, and the throttle body 129 is connected to the connection cylinder portion 138 via the insulator 128 so that the axis of the intake passage 130 is arranged on the second plane PL2. Yes.
[0071]
  According to such a mounting structure of the fuel injection valve 135, the throttle body 129 can be exposed to the outside of the cylinder head 33 except for the front end portion of the fuel injection valve 135 while the throttle body 129 is brought close to the cylinder head 33. The fuel injection valve 135 can be effectively cooled while the entire engine E including the body 129 can be downsized.
[0072]
  Further, the insulator 128 is formed so as to be bent in the second plane PL2, and the throttle drum 133 provided in the throttle body 129 is disposed on the side opposite to the cylinder head 33. The body 129 can be brought closer to the cylinder head 33 side, and the fuel injection valve 135 does not interfere with the arrangement of the throttle wire 134 wound around the throttle drum 133.
[0073]
  Moreover, the engine E has the intake valve 118 and the exhaust valve so that the operation axis intersects in a substantially V shape on the projection onto the first plane PL1 including the cylinder axis C and the axis of the inlet portion 121a of the intake port 121. 119... Are arranged in the cylinder head 33 so as to be openable and closable, and a camshaft 141 having an axis substantially parallel to the axis of the inlet portion 121a of the intake port 121 is arranged between the intake valves 118 and the exhaust valves 119. Thus, the width of the upper portion of the cylinder head 33 is made as small as possible, thereby increasing the number of protrusions of the fuel injection valve 135 from the cylinder head 33 and making the fuel injection valve 135 more effective. Can be cooled.
[0074]
  Since the cylinder head 33, the fuel injection valve 135, and the throttle body 129 of the engine E, which is a single cylinder, are disposed between the pair of left and right main frames 13 and 13 included in the vehicle body frame 11, the pair of left and right main frames 13 and 13 are disposed. The fuel injection valve 135 and the throttle body 129 can be disposed while narrowing the interval therebetween, which can contribute to the improvement of the rider's straddle and riding comfort.
[0075]
  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.
[0076]
【The invention's effect】
  As aboveBookAccording to the invention, most of the fuel injection valve excluding the tip of the fuel injection valve can be exposed to the outside of the cylinder head while bringing the throttle body close to the cylinder head. Enables effective cooling of the valve. AlsoSince the insulator is bent, the throttle body can be brought closer to the cylinder head side, and the fuel injection valve does not get in the way of arranging the throttle wire wound around the throttle drum.
[0077]
  Also especiallyAccording to invention of Claim 3, the width | variety of the upper part of a cylinder head can be made as small as possible, and by this, the protrusion part from the cylinder head of a fuel injection valve can be increased, and a fuel injection valve can be cooled more effectively. .
[0078]
  Also especiallyAccording to the invention of claim 4,SelfThe fuel injection valve and the throttle body can be arranged while narrowing the distance between the pair of left and right frames included in the motorcycle, which can contribute to improvement of the rider's straddle and ride comfort.
[Brief description of the drawings]
[Fig. 1] Side view of a small motorcycle
FIG. 2 is a view seen from the direction of arrow 2 in FIG. 1 with the fuel tank and the riding seat omitted.
Fig. 3 Lower side view of the engine
4 is a cross-sectional view taken along line 4-4 of FIG.
[Fig. 5] Upper vertical side view of the engine
6 is a partially cutaway plan view seen from the direction of arrow 6 in FIG. 5 with the head cover omitted.
7 is a sectional view taken along line 7-7 in FIG.
8 is a bottom view of the main part of the cylinder head taken along line 8-8 in FIG. 7;
[Explanation of symbols]
11. Body frame
13. Main frame
33 ... Cylinder head
34... Head cover
118 ... Intake valve
119 ... Exhaust valve
121 ... Intake port
121a ・ ・ Inlet of intake port
128: Insulator
129 ... Throttle body
130: Intake passage
131 ... Body
132 ... Throttle valve
133 ... Throttle drum
135 ... Fuel injection valve
136... Mounting hole
138 ... Connection cylinder part
140 ... Valve operated device
141 ... camshaft
144 ... Valve chamber
C: Cylinder axis
E ... Engine
PL1, PL2 ... Plane

Claims (4)

Left and right main frames (13) extending downward from the head pipe (12), down tubes (14) extending downward from front portions of the main frames (13), and rear ends of the left and right main frames (13) The vehicle body frame (11), which includes a left and right center frame (15) that is integrally connected to the left and right and extends between the rear portions of the left and right main frames (13), is connected to a fuel injection engine ( E) is a motorcycle in which the upper end portion of the rear cushion (24) is attached to the center of the cross member (17) in the left-right direction,
The engine (E) distributes the intake passage (130) through a cylinder head (33) provided with an intake port (121) and a body (131) having an intake passage (130) communicating with the intake port (121). Ru with a throttle valve capable of controlling the area and (132) the throttle body is made is arranged to be opened and closed (129), a fuel injection valve for injecting fuel toward the intake port (121) and (135) In things,
The cylinder head (33) has a connecting cylinder portion that protrudes rearward from the coupling portion of the cylinder head (33) and the head cover (34) and forms an inlet portion (121a) of the intake port (121) in a rearward direction. (138) is integrally provided so that the axis of the inlet portion (121a) is disposed in a plane (PL2) substantially orthogonal to the cylinder axis (C),
An attachment hole (136) for fitting the tip of a fuel injection valve (135) attached to the cylinder head (33) in a liquid-tight manner so as to inject fuel toward the intake port (121) is the connecting cylinder. Part (138),
The throttle body (129) is located in front of the cross member (17) and between the left and right main frames (13), and the intake passage (130) axis of the throttle body (129) is the plane ( PL2) is connected to the connecting tube portion (138) via an insulator (128) ,
The left and right main frames (13) are formed so that the mutual distance between the portions of the main frames (13) sandwiching the throttle body (129) increases as the cross member (17) approaches. A seat (26) is disposed above the main frame (13) so as to cover the throttle body (129) and the insulator (128) from above,
The insulator (128) is formed so as to bend in one side in the left-right direction within the plane (PL2), and the axis of the intake passage (130) of the throttle body (129) connected to the insulator (128) is planar. The throttle body (129) is inclined to the one side in the left-right direction toward the rear, and the side surface on the other side in the left-right direction of the body (131) in the throttle body (129) and the main frame (13 on the other side in the left-right direction). ), A throttle drum (133) that rotates integrally with the throttle valve (132) is disposed,
Between the upstream end of the intake passage (130) of the throttle body (129) and the air cleaner (165) disposed behind the throttle body (129) and supported by the vehicle body frame (11) is the rear cushion ( The motorcycle according to claim 24, wherein the motorcycle is connected via an intake passage arranged to bypass the side of the rear cushion (24) on one side in the left-right direction of 24) . The motorcycle according to claim 1, wherein a throttle wire (134) wound around the throttle drum (133) extends rearward . In the cylinder head (33), the operating axis intersects in a substantially V shape on a projection view onto the plane (PL1) including the cylinder axis (C) and the axis of the inlet port (121a) of the intake port (121). In this way, the intake valve (118) and the exhaust valve (119) are arranged to be openable and closable, and have an axis substantially parallel to the axis of the inlet portion (121a) of the intake port (121). A valve gear (140) having a camshaft (141) disposed between (118) and the exhaust valve (119) includes the cylinder head (33) and a head cover (34) coupled to the cylinder head (33). 3. The motorcycle according to claim 1, wherein the two- wheeled motor vehicle is accommodated in a valve train chamber (144) formed therebetween. It said engine (E) is between the left and right main frames (13), the single-cylinder as before Symbol the fuel injection valve with the throttle body (129) (135) and said cylinder head (33) is arranged The motorcycle according to any one of claims 1 to 3, wherein the motorcycle is configured .

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