JP2007270786A - Fuel pump for v-type internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel pump for a V-type internal combustion engine which is in a compact structure and can improve pump performance. <P>SOLUTION: In the V-type internal combustion engine having fuel injection systems 66 and 67 for injecting fuel into a suction guide member 60 which guides suction gas into a combustion chamber, the fuel pump is arranged on the sides of cylinder blocks 12 and 22 or cylinder heads 13 and 23 offset to either of the left and right sides. The fuel pump can be also arranged between front and back banks 10b and 10c, or is arranged at a lower part of a rear wall surface and in front of a crankshaft 20, or is arranged at a rear part of a front wall surface and at an upper part of a transmission case 11B provided at a rear part of a crankcase 11A. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel pump for a V-type internal combustion engine for supplying fuel to a fuel injection device that injects fuel into an intake air introduction member.

As means for supplying fuel to the combustion chamber, a fuel pump that discharges fuel stored in the fuel tank, and a carburetor or injector that injects fuel into an intake air introduction member connected to an intake port connected to the combustion chamber And a fuel pump discharge port and a fuel injection device suction port connected by a pipe. As this fuel pump, a mechanically driven pump driven by an internal combustion engine is known (for example, see Patent Document 1).

JP 57-113953 A

  Patent Document 1 proposes a fuel pump layout in which a fuel pump is provided in a front portion of a cylinder head in an in-line four-cylinder engine, and the operation performance is improved by cooling with traveling wind. Thus, not only in a parallel type but also in a V-type internal combustion engine, the performance of the fuel pump is improved, and the fuel pump is optimally arranged so as not to increase the size and weight of the internal combustion engine. Configuration is required.

  In view of such problems, an object of the present invention is to provide a fuel pump for a V-type internal combustion engine that can be configured compactly and has an arrangement and configuration that improves the performance of the fuel pump.

  To achieve the above object, a fuel pump for a first V-type internal combustion engine according to the present invention includes a crankcase in which a crank chamber in which a crankshaft extending in the left-right direction is rotatably accommodated, A cylindrical cylinder bore coupled to the upper portion of the case and having a piston inserted therein is formed, and the first and second cylinder bores extend so that the axis of each cylinder bore forms a V-shape as viewed from the side with respect to the crankshaft. Two cylinder blocks, a first cylinder head covering the cylinder bore of the first cylinder block and coupled to the upper part, a second cylinder head covering the cylinder bore of the second cylinder block and coupled to the upper part, 1 cylinder block and 1st cylinder head, 2nd cylinder block and 2nd cylinder head An intake air introduction member for introducing intake air into a combustion chamber formed by being surrounded by the upper surface of the piston, and a fuel injection device that is provided in the intake air introduction member and injects fuel into the intake air introduction member. In a V-type internal combustion engine configured to have a mechanically driven fuel pump that supplies fuel to a fuel injection device, the first and second cylinder blocks are offset in either of the left and right directions, The fuel pump is disposed on the side surface opposite to the offset direction among the left and right side surfaces of the cylinder block and the cylinder head.

  At this time, rotation of the first and second camshafts rotatably provided in the first and second cylinder heads and the rotation of the crankshaft are decelerated and transmitted to the first and second camshafts. It is preferable that the fuel pump is driven by a gear constituting the cam gear train. A body frame provided to cover at least one side of the first and second cylinder heads; and a crankshaft rotatably provided in each of the first and second cylinder heads. The first and second camshafts are decelerated with respect to the rotation and the fuel pump is provided at the end of the camshaft provided in the cylinder head covered by the vehicle body frame. It may be driven.

  A fuel pump for a V-type internal combustion engine according to a second aspect of the present invention includes a crankcase in which a crank chamber in which a crankshaft extending in the left-right direction is rotatably accommodated is formed, and an upper portion of each crankcase. First and second cylinder blocks that are coupled to each other to form a cylindrical cylinder bore into which a piston is inserted and disposed so that the axis of each cylinder bore extends from the crankshaft as a base point to form a V shape in a side view. A first cylinder head coupled to the upper portion of the first cylinder block and covering the cylinder bore of the first cylinder block; a second cylinder head coupled to the upper portion of the second cylinder block and covering the cylinder bore; and the first cylinder block And between the first cylinder head and the second cylinder block and the second cylinder head, An intake air introduction member for introducing intake air into a combustion chamber formed by being surrounded by the upper surface of the stone, and a fuel injection device that is provided in the intake air introduction member and injects fuel into the intake air introduction member A mechanically driven fuel pump for supplying fuel to a fuel injection device in a V-type internal combustion engine, wherein the fuel pump includes a first cylinder block and a first cylinder head, a second cylinder block and a second cylinder block. Between the two cylinder heads and below the intake air introduction member.

  At this time, rotation of the first and second camshafts rotatably provided in the first and second cylinder heads and the rotation of the crankshaft are decelerated and transmitted to the first and second camshafts. The cam pump may be driven by a gear constituting the cam gear train.

  A fuel pump for a V-type internal combustion engine according to a third aspect of the present invention includes a crankcase formed therein with a crank chamber in which a crankshaft extending in the left-right direction is rotatably accommodated, and an upper portion of each crankcase. A cylindrical cylinder bore into which a piston is inserted and disposed is formed, and the axis of each cylinder bore extends so as to form a V-shape in a side view with the crankshaft as a base point, and a first cylinder disposed forward. Cylinder block and a second cylinder block arranged at the rear, a first cylinder head coupled to the upper portion covering the cylinder bore of the first cylinder block, and an upper portion covering the cylinder bore of the second cylinder block The coupled second cylinder head, the first cylinder block and the first cylinder head, and the second cylinder block An intake air introduction member for introducing intake air into the combustion chamber formed between the piston and the second cylinder head and surrounded by the upper surface of the piston, and an intake air introduction member provided on the intake air introduction member. In a V-type internal combustion engine configured to include a fuel injection device that injects fuel therein, a mechanically driven fuel pump that supplies fuel to the fuel injection device, the fuel pump being a first cylinder block And provided below the rear wall surface of the first cylinder head and in front of the crankshaft.

  At this time, a balancer shaft provided between the crankshaft and the fuel pump and driven to rotate by the crankshaft may be provided, and the fuel pump may be driven by the balancer shaft.

  A fuel pump for a V-type internal combustion engine according to a fourth aspect of the present invention includes a crankcase in which a crank chamber in which a crankshaft extending in the left-right direction is rotatably accommodated is formed, and an upper portion of each crankcase. A cylindrical cylinder bore into which a piston is inserted and disposed is formed, and the axis of each cylinder bore extends so as to form a V-shape as viewed from the side with respect to the crankshaft, and is disposed in front. A first cylinder block and a second cylinder block arranged at the rear, a first cylinder head coupled to the upper part of the cylinder bore of the first cylinder block, and a cylinder bore of the second cylinder block. A second cylinder head coupled to the upper part of the crankcase and a rear side of the crankcase. Between the transmission case provided with the power transmission device for transmitting the power to the wheels, the first cylinder block and the first cylinder head, and the second cylinder block and the second cylinder head, An intake air introduction member for introducing intake air into a combustion chamber formed by being surrounded by the upper surface of the piston, and a fuel injection device that is provided in the intake air introduction member and injects fuel into the intake air introduction member In the V-type internal combustion engine, a mechanically driven fuel pump that supplies fuel to the fuel injection device, the fuel pump being behind the rear wall surface of the second cylinder block and the second cylinder head, It is provided above the transmission case.

  In the fuel pump for the V-type internal combustion engine according to the first aspect of the present invention, since the fuel pump is provided on the side surfaces of the cylinder block and the cylinder head, the internal combustion engine is not enlarged in the front-rear and up-down directions. Further, since the fuel pump is close to the intake air introduction device, the length of the pipe connecting the fuel injection device and the fuel pump can be shortened, leading to a reduction in pump driving loss. Here, the cylinder block and the cylinder head of this configuration example are provided offset in either of the left and right directions, and the fuel pump is disposed on the side surface opposite to the offset direction. That is, since the fuel pump is disposed in the space formed by the offset, the internal combustion engine is not enlarged in the left-right direction when the fuel pump is provided on the side surface of the cylinder block or the cylinder head.

  At this time, since the fuel pump can be driven at a low rotation with respect to the crankshaft by driving the fuel pump with a gear constituting a cam gear train that is a reduction mechanism, the pump driving loss can be reduced. In addition, by driving the fuel pump using the gears already installed in the internal combustion engine, the number of components of the drive mechanism provided exclusively for driving the fuel pump is reduced, reducing the weight and cost of the internal combustion engine. Is planned. Furthermore, the rotational fluctuation of the gear can be attenuated by utilizing the drive friction of the pump, and the backlash of the cam gear train can be eliminated.

  In addition, by disposing the fuel pump at the end of the camshaft provided on the cylinder head covered with the body frame, the fuel pump can be driven at the same low speed as described above, so that the pump driving loss can be reduced. Since the fuel pump is driven using a shaft already installed in the internal combustion engine, the weight and cost of the internal combustion engine can be reduced. Furthermore, since the fuel pump is covered with the vehicle body frame, a fuel pump with high maintainability can be provided without providing a dedicated protective member when the fuel pump is provided on the side surface of the cylinder head.

  Further, according to the fuel pump of the V-type internal combustion engine according to the second aspect of the present invention, the fuel pump is provided in a V-shaped space surrounded by the first cylinder block and the second cylinder block. By effectively using this V-shaped space, the internal combustion engine is prevented from being enlarged. Note that an intake air introduction member is provided in this space. Therefore, the pipe connecting the fuel injection device and the fuel pump is shortened, and the pump driving loss is reduced.

  At this time, by driving the fuel pump with a gear constituting the cam gear train that is a reduction mechanism, similarly to the above, the pump drive loss is reduced, the internal combustion engine is reduced in weight and cost, and the backlash of the cam gear train is reduced. Removal is attempted.

  Further, according to the fuel pump of the V-type internal combustion engine according to the third aspect of the present invention, the fuel pump is disposed below the front wall surface of the first cylinder block and the first cylinder head disposed in front and in front of the crankshaft. By being provided at this position, the fuel pump is air-cooled by the traveling wind when the vehicle is traveling, and the operating performance is improved.

  At this time, the weight and cost of the internal combustion engine can be reduced as described above by driving the fuel pump by utilizing the rotation of the balancer shaft already installed in the internal combustion engine.

  Further, according to the fuel pump for the V-type internal combustion engine according to the fourth aspect of the present invention, the space formed above the transmission case and behind the second cylinder block can be effectively used, and the internal combustion engine can be downsized. .

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the direction of the arrow U in the figure is upward and the direction of the arrow F is forward, and the direction indicated by these arrows corresponds to the direction seen by the motorcycle driver.

  FIG. 1 shows a motorcycle MC equipped with an engine 10 provided with a fuel pump of a V-type internal combustion engine according to the present invention. The motorcycle MC is formed of an aluminum alloy and is suspended from a vehicle body frame 1 with the engine 10 as a frame member, a front fork FF attached to the head pipe 2 of the vehicle body frame 1, and a front wheel FW attached to the front fork FF. , A handle H connected to the front fork FF, a front seat FS and a rear seat RS attached to a seat rail (not shown) extending rearward from the vehicle body frame 1, and a front end portion at the rear end portion of the engine 10. The swing arm SA pivoted, the rear wheel RW attached to the rear end of the swing arm SA, the air chamber 63 and the fuel tank 71 attached to the upper part of the body frame 1, and the exhaust attached to the engine 10. The silencer M connected to the pipe 65 is a main component, and the vehicle body Over beam 1 is covered by the cowling C.

  As shown in FIGS. 1 and 3, the vehicle body frame 1 includes a head pipe 2 positioned at the front end, a pair of main frames 3 that are separated from the head pipe 2 and extend rearward, and a front end of the main frame 3. It has a twin tube structure composed of a pair of left and right hangers 4 extending rearward and downward from the portion. The engine 10 is fastened to the rear end portion of the main frame 3 and the lower end portion of the hanger 4, is suspended from the vehicle body frame 1, and is accommodated in the inner space of the vehicle body frame 1.

  2 to 6 show an engine 10 provided with the fuel pump of the first configuration example. The engine 10 is a four-stroke / V-type four-cylinder reciprocating engine. The engine 10 is provided above the crankcase 11A and disposed forward, and is disposed above the crankcase 11A and rearward. The second cylinder block 22 arranged, the first cylinder head 13 provided above the first cylinder block 12, and the second cylinder head 23 provided above the second cylinder block 22 are configured. In addition, a V-shaped space 10 a is formed between the first cylinder block 12 and the first cylinder head 13 and the second cylinder block 22 and the second cylinder head 23. Of the cylinder blocks 12, 22 and cylinder heads 22, 23 forming the V-shape, the first cylinder block 12 and the first cylinder head 13 are referred to as the front bank 10b, and the second cylinder block 22 and the second cylinder head 23 are referred to as the front bank 10b. This will be referred to as rear bank 10c.

  Here, in the engine 10, the crankcase 11A has an upper and lower halved structure in which the upper case half 31 and the lower case half 32 are joined and molded. Further, the upper case half 31, the first cylinder block 12 and the second cylinder block 22 are integrally formed to constitute a large upper case 11.

  The crankshaft 20 is rotatably supported on the split surfaces of the case halves 31 and 32 by the crankcase 11A. The crankshaft 20 has three journals, and crank pins 20b and 20b are formed between adjacent journals. A left cover 33 is attached to cover the left side surface of the crankcase 11 </ b> A, and a left auxiliary device chamber 33 a is formed inside the left cover 33. A right cover 34 is attached to cover the right side surface of the crankcase 11 </ b> A, and a right accessory chamber 34 a is formed inside the right cover 34. The left end 20d of the crankshaft 20 protrudes from the left side surface of the crankcase 11A and is accommodated in the left auxiliary device chamber 33a. A generator 35 driven by the crankshaft 20 is attached to the left end 20d. The right end 20e of the crankshaft 20 protrudes from the right side surface of the crankcase 11A and is accommodated in the right accessory chamber 34a. The two crank pins 20b and 20b are accommodated in the crank chamber 11a.

  As shown in FIGS. 2 and 3, two cylinder bores 14 and 24 are formed in the cylinder blocks 12 and 22, respectively. Pistons 15 and 25 are inserted into the cylinder bores 14 and 24 so as to be slidable in the axial direction. The axis lines of the cylinder bores 14 and 24 extend from the crankshaft 20 so as to form a V shape in the front-rear direction. The crankshaft 20 and the pistons 15 and 25 are connected via connecting rods 16 (16a and 16b) and 26 (26a and 26b), and the pistons 15 and 25 reciprocate in conjunction with the rotation of the crankshaft 20.

  Here, the pistons 15 and 25 are arranged side by side on both cylinder blocks 12 and 22, but the left piston is connected to the left crank pin 20b, and the right piston is connected to the right crank pin 20b. Two connecting rods 16 and 26 are pivotally connected to one crankpin 20b. In each crank pin 20b, connecting rods 16a and 16b connected to pistons 15 and 15 provided on the first cylinder block 12 are pivoted on the right part, and pistons 25 and 16 provided on the second cylinder block 22 on the left part. The connecting rods 26a and 26b connected to 25 are pivoted. For this reason, the first cylinder block 12 is offset to the right with respect to the second cylinder block 22, and the second cylinder block 22 is offset to the left with respect to the first cylinder block 12, and the left side of the front bank 10b. A space is formed between the vehicle body frame 1 and the right side of the rear bank 10c.

  Cylinder heads 13 and 23 are provided to cover the cylinder bores 14 and 24, and combustion chambers 17 and 27 are formed surrounded by the cylinder heads 13 and 23, the inner peripheral surfaces of the cylinder bores 14 and 24, and the pistons 15 and 25. Yes. A spark plug 18 is attached to the cylinder heads 13 and 23 with the electrode portions facing the combustion chambers 17 and 27. Further, head covers 19 and 29 are attached to the cylinder heads 13 and 23 so as to cover the top.

  Two intake ports 41 and two exhaust ports 42 that open to the combustion chambers 17 and 27 are formed inside the cylinder heads 13 and 23. Further, one end side communicates with the intake port 41 and the other end side communicates with the outside. And an exhaust passage 44 having one end connected to the exhaust port 42 and the other end connected to the outside.

  In the first cylinder head 13, the intake passage 43 is formed to extend rearward from the combustion chamber 17 and opens to the rear wall surface, and the exhaust passage 44 is formed to extend forward from the combustion chamber 17 and opens to the front wall surface. In the second cylinder head 23, the intake passage 43 is formed to extend forward from the combustion chamber 27 and opens to the front wall surface, and the exhaust passage 44 is formed to extend rearward from the combustion chamber 27 and open to the rear wall surface.

  As shown in FIG. 1, exhaust pipes 65 a and 65 b are connected to the front wall surface of the first cylinder head 13 and the rear wall surface of the second cylinder head 23 so as to communicate with the exhaust passage 44. The exhaust pipe 65a connected to the first cylinder head 13 extends downward at the front of the engine 10, is bent and extends backward, and extends upward along the rear end of the engine 10, and is provided with a front seat FR. And the lower part of the rear seat RS extends rearward and is connected to the silencer M. The exhaust pipe 65b connected to the second cylinder head 23 extends rearward of the engine 10 and extends rearward below the front seat FS and the rear seat RS and is connected to the silencer M.

  The cylinder heads 13 and 23 are provided with an intake valve 45 for opening and closing the intake port 41 and an exhaust valve 46 for opening and closing the exhaust ports 42 and 42.

  An intake camshaft 47 and an exhaust camshaft 48 are provided between the cylinder heads 13 and 23 and the head covers 19 and 29, respectively, so as to be freely rotatable side by side. An intake camshaft 47 is provided on the V-shaped space 10a side. Both camshafts 47 and 48 are provided with cams 49 and 50 on their outer peripheral surfaces, respectively. Both the camshafts 47 and 48 are driven by the rotation of the crankshaft 20 being transmitted through the cam gear train 51, and rotate at half the speed with respect to the crankshaft 20. Cam gear chambers 37 and 38 communicating with the right auxiliary device chamber 34 a are formed on the right side of the cylinder blocks 12 and 22 and the cylinder heads 13 and 23, and the cam gear train 51 is accommodated in the cam gear chambers 37 and 38.

  The cam gear train 51 meshes with the cam drive gear 51a, which is coupled to the right end portion 20e of the crankshaft 20 protruding into the right auxiliary device chamber 34a, and the first cam accommodated in the cam gear chambers 37 and 38. First cam idle gears 51c, 51c provided on the idle shafts 51b, 51b so as to be relatively rotatable, mesh with the first cam idle gear 51c, and second cam idle shafts 51d, accommodated in the cam gear chambers 37, 38, Second cam idle gears 51e, 51e provided rotatably on 51d, first cam driven gears 51f, 51f meshed with second cam idle gear 51e and coupled to intake camshaft 47, and second cam The second cam driven gears 51g, 51g engaged with the idle gear 51e and coupled to the exhaust camshaft 48 Constructed.

  The cam 48 of the intake camshaft 47 is in contact with the upper end of the intake valve 45, and the cam 50 of the exhaust camshaft 48 is in contact with the upper end of the exhaust valve 46. When both camshafts 47 and 48 rotate, the intake valve 45 and the exhaust valve 46 are pushed at the upper ends by the cams 49 and 50 and pushed down against the urging force of the valve spring, and the intake valve 45 is always closed. The port 41 is opened, and the exhaust port 42 that the exhaust valve 46 is always closed is opened.

  As shown in FIG. 6, a starter motor 52 is attached to the front lower side of the crankshaft 20, the spindle of the starter motor 52 is accommodated in the right auxiliary device chamber 34a, and the rotational driving force of the starter motor 52 is accommodated. Is provided with a starting speed reduction mechanism 53 for transmitting the torque to the crankshaft 20. The start deceleration mechanism 53 includes first and second start idle shafts 53a and 53b supported by the lower case half 32 and the right cover 34, a pinion 53c attached to the spindle of the starter motor 52, and a pinion 53c, respectively. A first start reduction gear 53d that is meshed and rotatably provided on the first start idle shaft 53a, and is integrally formed with the first start reduction gear 53d and provided rotatably on the first start idle shaft 53a. The second start reduction gear 53e meshes with the second start reduction gear 53e, and meshes with the third start reduction gear 53f and the third start reduction gear 53f that are rotatably provided on the second start idle shaft 53b. A fourth start reduction gear 53g connected to the left end portion 20d of the crankshaft 20 via a one-way clutch 54. It is.

  When the rotational speed of the crankshaft 20 exceeds the rotational speed of the fourth start reduction gear 53g, the one-way clutch 54 becomes free, and the power transmission between the fourth start reduction gear 53g and the crankshaft 20 is interrupted. The first start idle shaft 53a is disposed in front of the crankshaft 20 and the second start idle shaft 53b is disposed in front of the first start idle shaft 53a and above the starter motor 52. Yes.

  A transmission case 11B that accommodates the power transmission device 55 is integrally formed behind the crankcase 11A. The power transmission device 55 is located behind the crankshaft 20 and rotatably supported on the split surfaces of the upper and lower case halves 31 and 32, and is located behind the main shaft 56 and is a transmission. The counter shaft 57 is rotatably supported by the case 11B, and is configured to shift the rotation of the crankshaft 20 and transmit it to the rear wheels. The right end portion 56a of the main shaft 56 protrudes from the side surface of the transmission case 11B and is accommodated in the right auxiliary device chamber 34a, and the left end portion 57a of the counter shaft 57 similarly protrudes leftward from the side surface of the transmission case 11B. ing.

  Between the crankshaft 20 and the main shaft 56, a primary gear train 58 is provided that decelerates and transmits the rotation of the crankshaft 20 to the main shaft 56. The primary gear train 58 meshes with the primary drive gear 58a provided between the cam drive gear 51a and the fourth start reduction gear 53g at the right end portion 20e of the crankshaft 20, and the primary drive gear 58a. The primary driven gear 58b is provided at the right end portion 56a so as to be relatively rotatable, and is accommodated in the right auxiliary device chamber 34a. The right end portion 56a of the main shaft 56 is provided with a main clutch 59 comprising an outer rotor 59a that can rotate relative to the main shaft 56 together with the primary driven gear 58b, and an inner rotor 59b coupled to the main shaft 56. It is accommodated inside the chamber 34a. The main clutch 59 is provided with clutch plates on both rotors 59a and 59b. When the clutch plates are engaged, the rotation of the primary driven gear 58b is transmitted to the main shaft 56, and when the clutch plate is released, the primary driven gear is provided. Power transmission from 58b to the main shaft 56 is interrupted.

  Between the main shaft 56 and the counter shaft 57, six transmission gear trains 55a for changing the speed of the rotation of the main shaft 56 and transmitting the rotation to the counter shaft 57 are provided. A desired gear position is set by selectively establishing. A drive sprocket 55b of a chain drive mechanism that transmits rotation to the rear wheel is provided at the left end portion of the counter shaft 57.

  An oil pan 40 for storing lubricating oil is coupled below the lower case half 32, and a trochoid oil pump for supplying the lubricating oil to various parts of the engine is provided below the lower case half 32. A drive shaft 21b for driving 21a is rotatably supported. Lubricating oil is sucked into the oil pump 21a through a suction pipe 21h extending upward from a strainer 21g provided inside the oil pan 40.

  The drive shaft 21b of the oil pump 21a is rotationally driven via an oil pump drive mechanism 21c provided inside the lower case half 15. The oil pump drive mechanism 21c includes an oil pump drive sprocket 21d integrally formed with a collar 55c provided integrally with a primary driven gear 58b at the right end portion 56a of the main shaft 56, and an oil pump provided on the drive shaft 21b. A driven sprocket 21e and an oil pump chain 21f spanned between the two sprockets 21d and 21e. Note that a lubricating oil passage is formed in the lower portion of the lower case half 32 to guide the lubricating oil pumped from the oil pump 21 a to various places. An oil filter 21i that is connected to the oil passage and filters the lubricating oil is provided.

  Here, the intake passages 43 formed in the first and second cylinder heads 13 and 23 are all open toward the V-shaped space 10a, and the intake introduction member 60 connected to these intake passages 43 is provided. It is provided inside the V-shaped space 10a. As shown in FIGS. 1 to 3, the intake air introduction member 60 includes an air chamber 63 provided above the engine 10, an air supply pipe 62 provided on a lower wall of the air chamber 63, and an upstream end 61 c having an air chamber. The throttle body 61 is connected to the lower wall 63 and communicates with the air supply pipe 62, the downstream end is connected to the intake passage 43, and the throttle body 61 extends vertically.

  The air chamber 63 is formed with a space inside by combining upper and lower chamber halves, and a filter element that bisects the space into a dirty side and a clean side is disposed therein. The dirty side has an opening communicating with the outside. On the clean side, the upper end opening of the air supply pipe 62 extending vertically is exposed. The throttle body 61 is connected to each intake passage 43, has an air passage 61 a formed therein, and is provided with a throttle valve 61 b having a variable opening, and controls the amount of intake air introduced from the air chamber 63 into the combustion chamber 17. It can be adjusted.

  As shown in the block diagram of FIG. 7, the fuel supply system of the engine 10 includes a fuel tank 71 provided in front of the air chamber 63 for storing fuel, and an electrically driven electric motor provided in the fuel tank 71. A fuel pump 72, a mechanically driven fuel pump 80 that uses the engine 10 as a drive source, four downstream injectors 66 that inject fuel into the downstream side of the intake air introduction member 60, and an internal upstream side of the intake air introduction member 60 The four upstream injectors 67 for injecting fuel into the fuel, the first fuel supply passage 75 connecting the discharge port of the electric fuel pump 72 and the suction port of the fuel pump 80, and the fuel pressure in the first fuel supply passage 75 are set to a predetermined value. A first regulator 70 a that regulates the pressure, and two first fuels that are connected to a branch path 76 of the first fuel supply path 75 and guide the fuel discharged from the first fuel pump 71 to the downstream injector 66. The revari pipe 73, the second fuel supply passage 77 connected to the discharge port of the fuel pump 80, the second regulator 70b for adjusting the fuel pressure in the second fuel supply passage to a predetermined pressure, and the branch of the second fuel supply passage 77 Connected to the downstream ends of the two second delivery pipes 74 connected to the passage 78 to guide the fuel discharged from the fuel pump 80 to the upstream injector 67, and the first and second delivery pipes 73, 74, the fuel is supplied. It is composed of return passages 79 and 79 leading to the tank 71.

  The fuel tank 71 is provided behind the air chamber 63 as shown in FIG. The upper surface of the fuel tank 71 is higher than the upper surface of the air chamber 63, and the front end of the fuel tank 71 is attached so as to cover the upper surface of the air chamber 63. The electric fuel pump 72 is provided at the rear bottom of the fuel tank 71 and is located above the rear bank 10c.

  The downstream injector 66 and the upstream injector 67 each have a fuel inlet at the upper end and an injection port at the lower end. The downstream injector 66 is mounted so that the injection port faces the downstream side of the throttle valve 61b and the upper end portion is inclined from the rear side of the throttle body 61 to the inside of the V-shaped space 10a. The upstream injector 67 has the injection port facing the clean side from the upper wall of the air chamber 63 and is disposed on the axis of the air passage 61 a, and the injection port faces the upper end opening of the air supply pipe 62. The fuel tank 71 is provided behind the air chamber 63 and above the main frame 3.

  The first and second delivery pipes 73 and 74 are injectors 66 attached to intake air introduction members 60 and 60 connected to intake passages 43 formed in the first and second cylinder heads 13 and 23, respectively. , 67 are provided separately at the front and rear in order to supply fuel. The first delivery pipe 73 is provided with the upper end portion of the downstream injector 66 extending left and right, and communicated with the fuel intake port of each downstream injector 66. The second delivery pipe 74 is provided with the upper end portion of the upstream injector 67 extending left and right, and communicated with the fuel intake port of each upstream injector 67.

  The downstream and upstream injectors 66 and 67 incorporate electromagnetically driven valves that open and close the injection ports. When an operation control signal is output by a control device (not shown), the valve is operated to release the injection port, and fuel is injected from the downstream injector 66 to the downstream side of the throttle valve 61b inside the throttle body 61, and upstream. Fuel is injected from the side injector 67 toward the air supply pipe 62.

  The electric fuel pump 72 and the mechanically driven fuel pump 80 connected in series as described above are operated and used together, and the fuel injection pressure applied to the upstream injector 67 is determined by the downstream injector. It becomes higher than the fuel injection pressure applied to 66. Therefore, the distance between the upstream injector 67 and the combustion chambers 17 and 27 is larger than that of the downstream injector 66, but the fuel injected from the upstream injector 67 reaches the combustion chambers 17 and 27. The time required is equal to or faster than that of the downstream injector 66.

  In this way, when the fuel injection pressure applied to the upstream injector 67 is set to a high pressure, the fuel can be injected in a short time, so the variable region of the fuel injection timing by the upstream injector 67 can be expanded, In addition, a great effect can be achieved even in an engine having a system (also referred to as a variable valve timing system) that makes the time for opening both the intake valve 45 and the exhaust valve 46 variable. In addition, the fuel is injected at a high pressure, whereby the atomization of the fuel is promoted, the volumetric efficiency and the combustion efficiency are improved, and the output is increased.

  Further, fuel is injected from the upstream and downstream injectors 66 and 67 at an optimal fuel injection sharing ratio according to the load of the engine 10 (for example, the opening degree of the throttle valve 61b), thereby further increasing the output of the engine 10. Is achieved. Here, the fuel injection sharing ratio refers to the ratio of the fuel injection amount from the upstream injector 67 (or the downstream injector 66) to the total fuel amount supplied to the combustion chambers 17 and 27.

  More specifically, higher output can be achieved by setting the fuel injection share of the upstream injector 67 to increase as the load of the engine 10 increases. As a method for setting the fuel injection share, in the low load region (for example, the opening degree of the throttle valve 61b is 0 to 30%), the fuel injection share of the upstream injector 67 is set to 0, and the medium load region (for example, the throttle valve 61b When the opening degree is 30 to 80%), the fuel injection share of the upstream injector 67 is simply increased to 0 to 100% in proportion to the load increase, and the high load region (for example, the opening degree of the throttle valve 61b is 80 to 100%). ), The fuel injection share of the upstream injector 67 may be set to 100%.

  As described above, in the low load region where the amount of fuel to be supplied to the combustion chambers 17 and 27 is small, the fuel injection share of the downstream injector 66 that is close to the combustion chambers 17 and 27 becomes high, and the fuel supply with high responsiveness is achieved. In the high load region, the fuel injection share of the upstream injector 67 with good volumetric efficiency and combustion efficiency is increased, and high output is exhibited.

  Further, the downstream and upstream injectors 66 and 67 are disposed on the downstream side or the upstream side with respect to the throttle valve 61b. Therefore, in the low load region, the fuel injected from the downstream injector 66 is supplied to the combustion chambers 17 and 27 without being inhibited by the throttle valve 61b. Further, in the high load region, since the opening degree of the throttle valve 61b is large, the fuel injected from the upstream injector 67 is supplied to the combustion chambers 17 and 27 without being inhibited by the throttle valve 61b.

  As described above, the upstream injector 67 is connected to the electric fuel pump 72 and the mechanically driven fuel pump 80 in series. By using the pressure of the electric fuel pump 72 as a preload of the fuel pump 80, the It is possible to supply high-pressure fuel several tens of times higher than

  Next, the fuel pump 80 of the first configuration example will be described with reference to FIG. The fuel pump 80 is a plunger pump, and is configured to convert the rotary motion into a reciprocating linear motion of the plunger by the action of a cam, and to inhale and discharge fuel by reciprocating the plunger.

  The fuel pump 80 includes a pump body 81, a pump drive shaft 82 that is rotatably accommodated in the pump body 81, a cam crest 85 that extends in the radial direction of the pump drive shaft 82, and an inside of the pump body 81. The plunger 83 is housed in a plunger housing portion extending in the radial direction of the pump drive shaft 82. A shaft cover 84 is attached to the pump body 81 after the pump drive shaft 82 is assembled. The pump body 81 is formed with a suction port 80a to which the downstream end of the first fuel supply path 75 is connected, and the shaft cover 84 is formed with a discharge port 80b to which the upstream end of the second fuel supply path 77 is connected. Both the suction port 80a and the discharge port 80b are communicated with the plunger accommodating portion. The plunger 83 is urged by a built-in spring, and is maintained in a state where the end abuts against the cam crest 85.

  In such a fuel pump 80, when the pump drive shaft 82 rotates, the plunger 83 reciprocates while maintaining the state in which the end is in contact with the cam peak 85 due to the action of the cam peak 85. When the plunger 83 moves downward, fuel from the first fuel supply passage 75 is sucked into the plunger accommodating portion from the suction port 80a, and when the plunger 83 moves upward, fuel is pumped from the discharge port 80b to the second fuel supply passage 77. The Since the plunger 83 reciprocates in the radial direction of the pump drive shaft 82, the fuel pump of this embodiment can be configured compactly in the axial direction of the pump drive shaft 82.

  The pump body 81 is attached to the right side surface of the second cylinder head 23, and the second cam in which the right end 82 a of the pump drive shaft 82 is accommodated in the cam gear chamber 38 formed in the second cylinder head 23 via the joint 91. It is connected to the idle shaft 51d. Thereby, the pump drive shaft 82 rotates integrally with the second cam idle shaft 51d. The second cam idle shaft 51d is supported by a shaft holder 89 provided in the cam gear chamber 38 and incorporating a bearing. Here, the cam gear train 51 increases the speed from the second cam idle gear 51e to the cam driven gears 51f and 51g to transmit power in order to reduce the size of the cam driven gears 51f and 51g and prevent the head covers 19 and 29 from becoming large. It is configured. That is, the second cam idle gear 51e is decelerated at a reduction ratio of 2 times or more with respect to the crankshaft 20, and the fuel pump is disposed on the front side of the frame, so that the cooling performance by traveling wind is improved.

  In the fuel pump 80 having such a configuration and arrangement, since the fuel pump 80 is provided on the right side surface of the second cylinder head 23, the engine 10 can be prevented from being enlarged in the front-rear and up-down directions. Further, since it is provided on the side surface of the cylinder head 23, it can be brought close to the intake air introduction member 60, the pipe length of the second fuel supply passage 77 can be shortened, and the pump drive loss can be reduced. The second cylinder head 23 is provided offset to the left with respect to the first cylinder head 13 because the piston 26 disposed in the second cylinder block 22 is connected to the left part of the crank pin 20b. It is done. Therefore, a predetermined space is secured between the second cylinder block 22 and the second cylinder head 23 and the vehicle body frame 1 on the right side. The fuel pump 80 is arranged using this space effectively, and the engine 10 is not enlarged in the left-right direction. The fuel pump 80 has a configuration in which the plunger 83 reciprocates in the radial direction of the pump drive shaft 82 and can be configured compactly in the axial direction of the pump drive shaft 82. For this reason, even if the pump body 81 is attached so that the axis of the pump drive shaft 82 extends outward from the right side surface, the protruding amount is small, and the fuel pump 80 can be sufficiently accommodated in this space.

  Further, when the fuel pump 80 is driven by the second cam idle shaft 51d that rotates integrally with the second cam idle gear 51e that constitutes the cam gear train 51, the fuel pump 80 operates at a low speed, so that the pump drive loss can be reduced. It is done. Further, since the mechanism for driving the fuel pump 80 uses the components of the cam gear train 51 already provided in the engine 10, it is provided exclusively for configuring the climate for driving the fuel pump 80. The parts are only the joint 91 that connects the shafts, and the weight and cost of the engine 10 can be reduced. Furthermore, it is possible to attenuate the rotational fluctuation of the cam gear train 51 by using the drive friction of the fuel pump 80, so that the backlash of the cam gear train 51 can be removed and the durability of the cam gear train 51 can be improved.

  The configuration shown in the first configuration example can be changed as appropriate. For example, the cam gear chambers 37 and 38 may be formed on the left side, and the fuel pump 80 may be driven by the second cam idle gear 51 e housed in the cam gear chamber 51 of the first cylinder head 13. At this time, since the first cylinder head 13 is offset to the right side with respect to the second cylinder head 23, the pump body 81 is attached to the left side surface of the first cylinder head 13 from the outside, so that it is the same as in the first configuration example. As a result, the fuel pump is arranged on the front side of the frame, so that the cooling performance by the traveling wind is improved.

  Further, the gear connected through the joint 91 may be, for example, the first idle gear 51 c as long as it is a gear constituting the cam gear train 51. However, in order to reduce the pump drive loss, it is possible to reduce the pump drive loss more effectively by driving the fuel pump 80 with the second cam idle gear 51e that rotates at the lowest speed in the cam gear train 51. it can.

  Next, the fuel pump 180 of the second configuration example will be described with reference to FIG. The fuel pump 180 has the same configuration as that of the first configuration example, and the plunger 183 reciprocates in the radial direction of the pump drive shaft 182, and can be configured compactly in the axial direction of the pump drive shaft 182.

  The fuel pump 180 has an intake camshaft 47 in which a pump body 181 is attached to the left side surface of the first cylinder head 13 from the outside, and a right end portion of the pump drive shaft 182 is provided in the second cylinder head 23 via a joint 191. Connected to the left end of Here, as shown in FIG. 3, the arrangement position of the intake camshaft 47 of the first cylinder head 13 is covered by the hanger 4 constituting the vehicle body frame 1 in a side view. The fuel pump 180 is provided so that the intake camshaft 47 and the pump drive shaft 182 are coaxially arranged and protrude leftward from the left side surface of the first cylinder head 13, but is configured to be compact in the axial direction. This leftward protrusion amount can be reduced. For this reason, even if the fuel pump 180 is attached at this position, the fuel pump 180 is sufficiently accommodated inside the hanger 4.

  When the intake camshaft 47 rotates, the pump drive shaft 182 rotates integrally, and the plunger 183 reciprocates due to the action of the cam crest 185 so that fuel is pumped to the second fuel supply path 77.

  Also in this configuration example, since the camshaft is connected to the intake camshaft 47 disposed on the side closer to the intake introduction member 60, the pipe length of the second fuel supply passage 77 can be shortened, and the pump drive loss is reduced. Is planned. In addition, the space formed with the right offset of the first cylinder block 13 is effectively used to avoid an increase in the size of the engine 10, but since the structure can be made compact in the radial direction, the protrusion amount is small and the vehicle body is sufficiently small. It can be stored in the hanger 4 constituting the frame 1. For this reason, it is not necessary to provide a member for specifically protecting the fuel pump 180 attached to the outside of the cylinder head 23, and a highly durable fuel pump can be configured by reducing the number of parts.

  In the second configuration example, the intake camshaft 47 and the pump drive shaft provided in the second cylinder head 23 may be configured to be integrally rotatable. At this time, since the first cylinder head 13 is offset to the left side, the left end portion of the pump drive shaft is connected to the right end portion of the intake camshaft 47 and the pump body is attached to the right side surface of the second cylinder head 23 from the outside. Is preferred. As a result, as in the above-described configuration, an increase in the size of the engine 10 is avoided by effectively utilizing the space, the rightward projecting amount is small, the fuel pump can be accommodated inside the main frame 3, and the number of parts can be reduced. A highly durable fuel pump can be configured.

  Further, as a mode of driving the fuel pump using the camshaft, FIGS. 10 and 11 show a fuel pump 280 of a third configuration example. The fuel pump 280 is rotatably supported inside the pump body 281, the pump drive shaft 282 having a left end face obliquely cut to form a swash plate cam face 285, and the pump body 281. It comprises a plunger 283 accommodated in a plunger accommodating portion formed extending in the axial direction of the pump drive shaft 282 so as to be able to reciprocate. The downstream end of the first fuel supply path 76 is connected to the pump body 281. The suction port 280a and the discharge port 280b to which the upstream end of the second fuel supply path 77 is connected are formed, and both the suction port 280a and the discharge port 280b are communicated with the plunger housing portion. The plunger 283 is biased by a built-in spring, and the state in which the ball member 284 attached to the end of the plunger 283 is in contact with the swash plate cam surface 285 formed on the pump drive shaft 282 is maintained. A groove 285a for guiding the ball member 284 is formed on the swash plate cam surface 285.

  In such a fuel pump 280, when the pump drive shaft 282 rotates, the plunger 283 reciprocates inside the plunger housing portion by the action of the swash plate cam surface 285. When the plunger 283 moves right (when moving in the direction of bottom dead center), fuel from the first fuel supply path 75 is sucked into the plunger housing portion, and when the plunger 283 moves left (when moving in the direction of top dead center). The fuel is pumped from the inside of the plunger housing portion to the second fuel supply passage 77. In the fuel pump of this embodiment, the plunger 283 reciprocates in the axial direction of the pump drive shaft 282, and can be configured compactly in the radial direction as a whole.

  The pump body 281 is attached to the left side surface of a pump bracket 219 a provided so as to protrude forward and upward from the right end portion of the upper surface of the head cover 19. A drive gear 291 is coupled to the right end portion of the intake camshaft 47, and a driven gear 292 that meshes with the drive gear 291 is coupled to the right end portion of the pump drive shaft 282.

  In this configuration example, the head cover 19 is protruded and attached to the outside. However, since the configuration can be made compact in the radial direction, enlargement of the engine 10 in the front-rear direction and the vertical direction is avoided. In addition, by transmitting power from the intake camshaft 47 to the pump drive shaft 282 not by chain transmission but by a gear train, the amount of protrusion from the head cover 19 can be reduced and the assembling property to the intake camshaft 47 and the head cover 19 can be reduced. Can be improved. Furthermore, since it is provided outside the head cover 19 attached to the first cylinder head 13 disposed on the front side, traveling wind is blown to the fuel pump 280 when the vehicle travels, and the fuel pump 280 is effectively cooled and driven. Performance is improved.

  Next, a fourth configuration example will be described with reference to FIG. The fuel pump 380 has the same configuration as that of the third configuration example, and the plunger reciprocates in the axial direction of the pump drive shaft 382, so that the fuel pump 380 can be configured compactly in the radial direction of the pump drive shaft 382.

  Here, the right side surface of the second cylinder block 22 is integrally formed with a pump bracket 322a that protrudes forward and is positioned below the V-shaped space 10a. A cover is attached from the right side of the pump bracket 322a to form a predetermined space 312b. A space 312b formed by the pump bracket 312a and the cover communicates with a cam gear chamber 37 formed in the second cylinder block 22.

  The pump body 381 is attached to the left side surface of the pump bracket 322a from the outside, protrudes leftward from the left side surface of the pump bracket 322a, and the right end portion of the pump drive shaft 382 is formed by the pump bracket 322a and the pump cover. Put in space. A pump driven gear 391 is coupled to the right end portion of the pump drive shaft 382, and the pump driven gear 391 meshes with a first cam idle gear 50c housed in a cam gear chamber 37 formed inside the first cylinder block 12. is doing.

  Thus, when the crankshaft 21 rotates, the cam gear train 51 is driven to rotate, and the pump driven gear 391 is driven to rotate, and the rotation of the crankshaft 20 is decelerated and transmitted to the pump drive shaft 382.

  In this configuration example, the fuel pump 380 is provided inside the V-shaped space 10a. For this reason, a dead space is effectively utilized and the enlargement of the engine 10 is avoided. In addition, since the fuel pump 380 can be configured to be compact in the radial direction, the occupied area in a side view can be reduced inside the V-shaped space 10a, and can be arranged offset to the lower closed portion of the V-shaped space 10a. A wide space can be secured.

  In addition, an intake air introduction member 60 is provided in the V-shaped space 10a, so that the pipe length of the second fuel supply path 77 can be shortened, and the pump drive loss can be reduced. At the same time, since it is kept away from the exhaust pipe, the thermal influence received from the exhaust pipe is reduced, and the heat insulating structure of the fuel pump 380 can be simplified. Furthermore, since the fuel pump 380 is driven by the first cam idle gear 51c already provided in the engine 10, the engine 10 can be reduced in size and weight as described above. At this time, since the drive friction of the fuel pump 380 acts on the cam gear train 51 and the rotational fluctuation applied to the cam gear train 51 can be attenuated, the backlash of the cam gear train 51 is removed and the durability is improved. .

  In the fourth configuration example, the intake camshaft 47 and the exhaust camshaft 48 are driven by the cam gear train 51. However, the drive sprocket coupled to the crankshaft 20 and the driven sprocket coupled to both camshafts. You may comprise a drive mechanism across an endless transmission belt. At this time, by configuring the endless transmission band with both cog belts and link type chains that can mesh the sprocket even from the outside, by providing a sprocket at the right end of the pump drive shaft and meshing this endless transmission band from the outside, The fuel pump can be arranged at the same location as in the above configuration example, and the same effect can be obtained. At this time, the rotation fluctuation of the endless transmission band can be attenuated by applying the driving friction of the fuel pump, and the durability of the endless transmission band can be improved.

  Next, the fuel pump 480 of the fifth configuration example will be described with reference to FIGS. The fuel pump 480 is configured in the same manner as in the first configuration example, and the plunger 483 reciprocates in the radial direction of the pump drive shaft 482 and is configured to be compact in the axial direction as a whole.

  Here, on the front lower side of the crankshaft 20, a balancer shaft 38 is provided behind the first start idle shaft 53a and in front of the second start idle shaft 53b, and is driven to rotate by the crankshaft 20. A balancer driven gear 39a is provided on the balancer shaft 38 so as to be relatively rotatable. The balancer driven gear 39a meshes with the primary drive gear 58a to form a balancer gear train 39, and rotates at the same speed as the crankshaft 20. Thus, in this engine 10, the drive element of the primary gear train 58 for performing primary deceleration of the power transmission device 55 and the drive element of the balancer gear train 39 for performing balancing are integrated. A balancer weight 39b is integrally formed on the side surface of the balancer driven gear 39a so that the balancer driven gear 39a can rotate integrally with the balancer driven gear 39a. Vibration associated with movement is reduced.

  Further, a pump drive gear 491 is integrally formed on the right side of the balancer driven gear 39a so as to be relatively rotatable on the balancer shaft 38. The pump drive gear 491 meshes with the pump drive gear 491 and has more teeth than the pump drive gear 491. A large pump driven gear 492 is provided. A shaft portion 492a protruding from the central portion is formed on the side surface of the pump driven gear 492, and this shaft portion 492a is rotatably supported by a bearing accommodated in a through hole 434a formed in the right cover 34. Yes. The through hole 434 a is formed in front of the support hole that supports the balancer shaft 38.

  The pump body 481 is attached to the right side of the right cover 34 from the outside, and the left end portion of the pump drive shaft 482 is connected to the shaft portion 492a of the pump driven gear 492 via a joint 493. Thus, when the balancer shaft 38 rotates, the rotation of the pump drive gear 491 is decelerated and transmitted to the pump driven gear 492, and the pump drive shaft 482 rotates integrally with the pump driven gear 492. The fuel pump 480 overlaps the starter motor 52 in a side view. The oil filter 21i is provided at the front lower portion of the lower case half 32, and the fuel pump 480 of this configuration example overlaps the oil filter 21i in a side view.

  In this configuration example, the starter motor 52 and the oil filter 21b are arranged so as to overlap in a side view, and the engine 10 can be configured compactly in the front-rear and up-down directions. Further, the fuel pump 480 is air-cooled when the vehicle travels by being provided at the front lower part of the engine 10. For this reason, the operating performance of the fuel pump 480 is improved. The engine 10 is configured to transmit power to the fuel pump 480 disposed at the front lower portion using the balancer shaft 38 and the balancer driven gear 39a already provided in the engine 10, and the configuration of the drive mechanism of the fuel pump 480 Parts can be reduced, and the weight and cost of the engine 10 can be reduced.

  The primary drive gear 58a, which is the driving element of the balancer gear train 39, is located on the left side on the crankshaft 20. For this reason, the side surface of the right cover 34 in the portion that supports the shaft portion 492 a of the pump driven gear 492 is offset to the left with respect to the position where the pump crankshaft 20 is disposed. For this reason, even if the fuel pump 480 is attached to the side surface of the right cover, the engine 10 does not increase in size in the left-right direction.

  In addition, when providing a fuel pump in the front lower part of the engine 10, it is not restricted to the said structure, It is also possible to drive a fuel pump using a starting deceleration mechanism. That is, the one-way clutch 54 is provided on the first start idle shaft 53b, and the first and second start reduction gears 53d and 53e are connected to the first start idle shaft 53d via the one-way clutch 54. That is, the rotation from the crankshaft 20 is always transmitted to the fourth start reduction gear 53g and the third start reduction gear 53f. The second start idle shaft 53b and the third start reduction gear 53f are configured to be integrally rotatable, the pump body is attached to the right side surface of the right cover from the outside, and the left end portion of the pump drive shaft is connected to the second start idle shaft 53b. Connect to

  With this arrangement, the fuel pump 580 is arranged in the front lower portion of the engine 10 so as to overlap the starter motor 52 and the oil filter 21b in a side view, as in the sixth configuration example. Therefore, the engine 10 can be configured compactly in the front-rear and up-down directions, and traveling air is blown to the fuel pump 580 when the vehicle is traveling, so that the performance of the fuel pump 580 is improved. Further, the engine 10 is configured to transmit power to the fuel pump 580 disposed in the front lower portion by using the start deceleration mechanism 53 already provided in the engine 10, and the number of components of the drive mechanism of the fuel pump 580 is reduced. Thus, the weight and the cost of the engine 10 can be reduced. Further, since the one-way clutch 54 is omitted from the crankshaft 20 that is a large member in the left-right direction, the crankshaft 20 is reduced in size in the axial direction, and the engine 10 can be reduced in the left-right direction.

  Next, the fuel pump 580 of the sixth configuration example will be described with reference to FIG. The fuel pump 580 is configured in the same manner as in the first configuration example, and the plunger reciprocates in the axial direction of the pump drive shaft 582, and can be configured compactly in the radial direction of the pump drive shaft 582.

  A pump bracket 531a that extends upward and is located behind the second cylinder block 22 and the second cylinder head 23 is formed in the upper case half 31 that constitutes the transmission case 11B. A suspension bracket 511z formed with a bolt hole for fastening the engine 10 to the vehicle body frame 1 extends upward and is integrally formed behind the pump bracket 531a. The right side of the pump bracket 531a is covered by the right cover 34, and the right auxiliary device chamber 34a is extended in the extending direction of the pump bracket 531a. A pump body 581 is attached to the left side surface of the pump bracket 531a from the outside, and the right end portion of the pump drive shaft 582 is accommodated in an extension portion of the right auxiliary device chamber 34a. The rear of the second cylinder block 22 (above the transmission case 11B) is a dead space in the first to sixth configuration examples.

  The collar 55c provided on the main shaft 56 is provided with a pump drive sprocket 591 that can rotate together with the primary driven gear 58b together with the oil pump drive sprocket 21d. A pump driven sprocket 592 is coupled to the right end of the pump drive shaft 582, and a pump chain 593 is spanned between the pump drive sprocket 591 and the pump driven sprocket 592. Thereby, the pump drive shaft 582 is rotationally driven at the same speed as the rotational speed of the primary driven gear 58b that rotates at a reduced speed with respect to the crankshaft 20.

  In this configuration example, the fuel pump 580 is provided at a position away from the intake air introduction member 60, but is positioned below the vehicle body frame 1 and positioned behind the cylinder block 22 and in front of the suspension bracket 511z. Thus, the space can be effectively used and the engine 10 can be downsized. In addition, the upper, lower, left and right are surrounded by other members in this way, and a fuel pump with high maintainability can be provided without providing a dedicated protective member.

  The configuration provided above the transmission case 11B is not necessarily limited to the above configuration. For example, the fuel pump is configured in the same manner as in the sixth configuration example, the pump bracket extends rearward from the right side surface of the second cylinder block 23, is integrally formed, the pump cover is attached to the right side of the pump bracket, and the second cylinder block An internal space communicating with the cam gear chamber 38 of the 22 is formed, and a gear connected to the right end portion of the pump drive shaft is engaged with the first cam idle gear 51c by attaching a pump body from the outside to the left side surface of the pump brat. Good. When the mechanism for driving the camshafts 47 and 48 is configured with an endless transmission band, the endless transmission band is a double cog belt or link type chain, the pump bracket is molded in the same way, and the pump body is mounted in the same way. The sprocket coupled to the end of the pump drive shaft may be engaged with the endless transmission band from the lower outside in the cam gear chamber 38.

1 is a left side view of a motorcycle equipped with an engine provided with a fuel pump of a V-type internal combustion engine according to the present invention. It is a left sectional view of the engine. It is right side sectional drawing of the said engine. It is sectional drawing of the said engine. It is sectional drawing of the said engine. It is sectional drawing of the said engine. It is a block diagram of the fuel supply system of the engine. It is sectional drawing of the engine which shows the fuel pump of the 1st structural example. It is sectional drawing of the engine which shows the fuel pump of the 2nd structural example. It is sectional drawing of the engine which shows the fuel pump of the 3rd structural example. It is sectional drawing of the engine which shows the fuel pump of the 3rd structural example. It is right side sectional drawing of the engine which shows the fuel pump of the 4th structural example. It is sectional drawing of the engine which shows the fuel pump of the 5th structural example. It is right side sectional drawing of the engine which shows the fuel pump of a 5th structural example. It is right side sectional drawing of the engine which shows the fuel pump of the 6th structural example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Engine, 10a ... V-shaped space, 10b ... Front bank, 10c ... Rear bank, 11A ... Crank case, 11B ... Transmission case, 12, 22 ... Cylinder block, 13, 23 ... Cylinder head, 20 ... Crank shaft, 37, 38 ... cam gear chamber, 47 ... intake camshaft, 48 ... exhaust camshaft, 51 ... cam gear train, 55 ... power transmission device, 56 ... main shaft, 60 ... intake intake member, 66, 67 ... injector, 80, 180 , 280, 380, 480, 580 ... Fuel pump

Claims (8)

A crankcase in which a crank chamber in which a crankshaft extending in the left-right direction is rotatably accommodated is formed;
Cylindrical cylinder bores are formed that are respectively coupled to the upper part of the crankcase and into which pistons are inserted, and the axis of each cylinder bore forms a V-shape as viewed from the side with respect to the crankshaft. Extending first and second cylinder blocks;
A first cylinder head coupled to the upper part of the first cylinder block and covering the cylinder bore; and a second cylinder head coupled to the upper part of the second cylinder block and covering the cylinder bore;
Intake into a combustion chamber provided between the first cylinder block and the first cylinder head and the second cylinder block and the second cylinder head and surrounded by the upper surface of the piston An intake introduction member for introducing
In a V-type internal combustion engine configured to include a fuel injection device that is provided in the intake air introduction member and injects fuel into the intake air introduction member,
A mechanically driven fuel pump for supplying fuel to the fuel injection device,
The first and second cylinder blocks are offset in either of the left and right directions;
The fuel pump for a V-type internal combustion engine, wherein the fuel pump is disposed on a side surface opposite to an offset direction of left and right side surfaces of the cylinder block and the cylinder head. First and second camshafts rotatably provided inside each of the first and second cylinder heads;
A cam gear train that transmits rotation of the crankshaft to the first and second camshafts;
The fuel pump for a V-type internal combustion engine according to claim 1, wherein the fuel pump is driven by a gear constituting the cam gear train. A vehicle body frame provided to cover at least one side of the first and second cylinder heads;
First and second camshafts rotatably provided inside each of the first and second cylinder heads,
2. The fuel for a V-type internal combustion engine according to claim 1, wherein the fuel pump is provided at an end portion of a camshaft provided on a cylinder head covered with the body frame and is driven by the camshaft. pump. A crankcase in which a crank chamber in which a crankshaft extending in the left-right direction is rotatably accommodated is formed;
Cylindrical cylinder bores are formed which are respectively coupled to the upper part of the crankcase and into which pistons are inserted, and the axis of each cylinder bore forms a V-shape as viewed from the side with respect to the crankshaft. Extending first and second cylinder blocks;
A first cylinder head that covers the cylinder bore of the first cylinder block and is coupled to the upper part; and a second cylinder head that covers the cylinder bore of the second cylinder block and is coupled to the upper part;
Intake into a combustion chamber provided between the first cylinder block and the first cylinder head and the second cylinder block and the second cylinder head and surrounded by the upper surface of the piston. An intake introduction member for introducing
In a V-type internal combustion engine configured to include a fuel injection device that is provided in the intake air introduction member and injects fuel into the intake air intake member,
A mechanically driven fuel pump for supplying fuel to the fuel injection device,
The fuel pump is provided between the first cylinder block and the first cylinder head and the second cylinder block and the second cylinder head and below the intake air introduction member. A fuel pump for a V-type internal combustion engine. First and second camshafts rotatably provided inside each of the first and second cylinder heads;
A cam gear train that decelerates the rotation of the crankshaft and transmits it to the first and second camshafts;
The fuel pump for a V-type internal combustion engine according to claim 4, wherein the fuel pump is driven by a gear constituting the cam gear train. A crankcase in which a crank chamber in which a crankshaft extending in the left-right direction is rotatably accommodated is formed;
Cylindrical cylinder bores are formed that are respectively coupled to the upper part of the crankcase and into which pistons are inserted, and the axis of each cylinder bore forms a V-shape as viewed from the side with respect to the crankshaft. A first cylinder block disposed in the front and a second cylinder block disposed in the rear;
A first cylinder head coupled to the upper part of the first cylinder block and covering the cylinder bore; and a second cylinder head coupled to the upper part of the second cylinder block and covering the cylinder bore;
Intake into a combustion chamber provided between the first cylinder block and the first cylinder head and the second cylinder block and the second cylinder head and surrounded by the upper surface of the piston An intake introduction member for introducing
In a V-type internal combustion engine configured to include a fuel injection device that is provided in the intake air introduction member and injects fuel into the intake air introduction member,
A mechanically driven fuel pump for supplying fuel to the fuel injection device,
A fuel pump for a V-type internal combustion engine, wherein the fuel pump is provided below the rear wall surface of the first cylinder block and the first cylinder head and in front of the crankshaft. A balancer shaft provided between the crankshaft and the fuel pump and driven to rotate by the crankshaft;
The fuel pump for a V-type internal combustion engine according to claim 6, wherein the fuel pump is driven by the balancer shaft. A crankcase in which a crank chamber in which a crankshaft extending in the left-right direction is rotatably accommodated is formed;
Cylindrical cylinder bores are formed that are respectively coupled to the upper part of the crankcase and into which pistons are inserted, and the axis of each cylinder bore forms a V-shape as viewed from the side with respect to the crankshaft. A first cylinder block disposed in the front and a second cylinder block disposed in the rear;
A first cylinder head coupled to the upper part of the first cylinder block and covering the cylinder bore; and a second cylinder head coupled to the upper part of the second cylinder block and covering the cylinder bore;
A transmission case provided behind the crankcase and provided with a power transmission device for transmitting rotation of the crankshaft to the wheel;
Intake into a combustion chamber provided between the first cylinder block and the first cylinder head and the second cylinder block and the second cylinder head and surrounded by the upper surface of the piston An intake introduction member for introducing
In a V-type internal combustion engine configured to include a fuel injection device that is provided in the intake air introduction member and injects fuel into the intake air introduction member,
A mechanically driven fuel pump for supplying fuel to the fuel injection device,
A fuel pump for a V-type internal combustion engine, wherein the fuel pump is provided behind a rear wall surface of the second cylinder block and the second cylinder head and above the transmission case. .

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