JP2006090247A - Parallel multiple cylinder engine for motorcycle and motorcycle loaded with parallel multiple cylinder engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parallel multiple cylinder engine capable of equalizing center of gravity in the left and right directions and reducing vehicle width in the vicinity of a knee position of a rider when loading the engine in a motorcycle. <P>SOLUTION: This parallel multiple cylinder engine E is provided with a crank shaft 32 for outputting rotation, an intake cam shaft 30 arranged by making the direction of axial length substantially parallel with the direction of vehicle width in an upper part of a cylinder head 20, an exhaust cam shaft 31 arranged substantially in parallel with the intake cam shaft 30 in front of the intake cam shaft 30, and a variable valve timing mechanism 68 having a hydraulic actuator 66 for changing difference in phase between the crank shaft 32 and the intake cam shaft 30. A rotation transmission mechanism 28 for transmitting rotation of the crank shaft 32 to the intake cam shaft 30 or the exhaust cam shaft 31 is provided in one side part of the cylinder head 20, and the hydraulic actuator 66 is provided in the other side part of the cylinder head 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a parallel multi-cylinder engine for a motorcycle and a motorcycle equipped with the parallel multi-cylinder engine, and more particularly to a parallel multi-cylinder engine having a variable valve timing mechanism that changes a phase difference between a crankshaft and an intake camshaft. And a motorcycle equipped with the same.

  As an engine mounted on a motorcycle, a parallel multi-cylinder engine in which a plurality of cylinders are arranged along the left-right direction of the vehicle body is often used. The engine houses a crankshaft along the left-right direction in a crankcase, and includes an intake / exhaust camshaft in parallel with the crankshaft at the upper part of the cylinder head. These crankshafts and camshafts (one or both of the intake camshaft and exhaust camshaft) rotate together via a rotation transmission mechanism such as a chain and sprocket, or a belt and pulley, and are provided on the camshaft. The intake valve and the exhaust bubble are opened and closed at a predetermined timing by the cam.

  That is, the cam has a predetermined unique shape (profile), and each valve is opened and closed by a predetermined opening / closing amount at a predetermined opening / closing timing according to this shape. When the intake valve is opened, the air-fuel mixture is sucked into the combustion chamber of the engine, and this air-fuel mixture is compressed by the piston and then ignited and burned at a predetermined timing. The combusted air-fuel mixture pushes back the piston when expanding, and rotates the crankshaft. Further, the exhaust valve is opened, and the combustion gas is discharged from the combustion chamber.

  By the way, the preferable opening / closing timing of the valve varies depending on the rotational speed of the engine. For example, when idling, it is preferable to reduce the time (overlap time) during which both the intake valve and the exhaust valve are open to stabilize combustion, and during high-speed rotation, when the intake valve is closed It is preferable to increase the intake charging efficiency by delaying the air flow from the usual time to increase the output.

As described above, in order to operate the engine suitably, it is necessary to drive the valve to open and close at different timings according to the engine speed. An engine with a variable valve timing mechanism is disclosed (see Patent Documents 1 to 4). Those disclosed in these patent documents are hydraulic variable valve timing mechanisms each including a vane actuator and an oil control valve (OCV) provided at an end of a camshaft, and the OCV is used as an actuator. The hydraulic pressure supplied to the engine is adjusted, the phase of the camshaft is changed, and the opening and closing timing of the intake valve is controlled.
JP-A-11-132016 Japanese Patent Laid-Open No. 11-280430 Japanese Patent Laid-Open No. 11-324629 JP 2002-242616 A

  However, in the case of the engine disclosed in the above publication, an actuator of a variable valve timing mechanism and a rotation transmission mechanism (for example, a sprocket) are provided at the same end of the intake / exhaust camshaft. When mounted on a motorcycle, it may be difficult to mount such a parallel multi-cylinder engine.

  That is, in the case of a motorcycle equipped with a parallel multi-cylinder engine, the center of the left and right of the vehicle body (position on the line connecting the front wheel and the rear wheel) and the center of the parallel multi-cylinder engine (the center of the cylinder row, In the case of a four-cylinder engine in which the first to fourth cylinders are arranged in order, the intermediate position between the second cylinder and the third cylinder) is configured to substantially match. Accordingly, if the actuator of the variable valve timing mechanism and the sprocket of the rotation transmission mechanism are provided on the same end of the intake / exhaust camshaft, it is difficult to equalize the engine center of gravity on the left and right.

  Accordingly, an object of the present invention is to provide a parallel multi-cylinder engine for a motorcycle capable of equalizing the left and right directions of the center of gravity, and a motorcycle equipped with the parallel multi-cylinder engine.

  The present invention has been made in view of the above-described circumstances, and a parallel multi-cylinder engine for a motorcycle according to the present invention has a crankshaft and a cylinder head with an axial length direction substantially parallel to a vehicle width direction. A variable valve having an intake camshaft disposed, an exhaust camshaft disposed substantially in front of the intake camshaft, and an actuator for changing a phase difference between the crankshaft and the intake camshaft A rotation mechanism for transmitting rotation of the crankshaft to the intake camshaft or the exhaust camshaft is provided on one side portion of the cylinder head, and the other side portion of the cylinder head is provided on the other side portion of the cylinder head. An actuator for the variable valve timing mechanism is provided.

  In such a configuration, the rotation transmission mechanism and the actuator of the variable valve timing mechanism are arranged separately on the left and right sides of the cylinder head, so that it is possible to equalize the engine center of gravity in the left-right direction.

  The rotation transmission mechanism may be provided on one side portion of the exhaust camshaft, and the actuator included in the variable valve timing mechanism may be provided on the other side portion of the exhaust camshaft. In such a configuration, the actuator of the variable valve timing mechanism and the rotation transmission mechanism (for example, a sprocket as a component example) are provided at the left and right ends of the exhaust camshaft provided on the upper front side of the cylinder head. Since each is provided, the size in the left-right direction (width direction) of the rear part of the cylinder head can be reduced as compared with the front part. Further, in the case of a motorcycle, the pilot's knee during traveling may be located in the vicinity of the rear part of the cylinder head of the engine. The size of the vehicle body in the width direction in the vicinity of the knee position can be reduced, and as a result, the driver's feeling of sitting comfort can be improved.

  The actuator of the variable valve timing mechanism includes a rotor that rotates integrally with the exhaust camshaft, and a housing that accommodates the rotor and rotates in conjunction with the rotor and rotationally drives the intake camshaft, You may comprise so that the phase difference between the said rotor and the said housing can be changed. In such a configuration, the exhaust camshaft can be rotated in the same phase as the crankshaft, and the intake camshaft is transmitted with the rotation of the exhaust camshaft via the actuator of the variable valve timing mechanism. It can be rotated by changing the phase difference with respect to the rotation.

  Further, a sensor for detecting the phase of the intake camshaft may be further provided on the side of the intake camshaft and behind the actuator of the variable valve timing mechanism or the rotation transmission mechanism. That is, if the actuator of the variable valve timing mechanism and the sprocket of the rotation transmission mechanism are provided at the left and right ends of the exhaust camshaft at the front part of the cylinder head, the size in the width direction of the rear part of the cylinder head is reduced, and the intake air Extra space is created near the left and right ends of the camshaft. Therefore, a sensor for detecting the phase of the intake camshaft can be provided by utilizing this surplus space.

  Further, a motorcycle equipped with a parallel multi-cylinder engine according to the present invention includes a main frame composed of a pair of left and right frame portions extending substantially along the front-rear direction of the vehicle body, and mounted on the main frame in the vehicle width direction. A parallel multi-cylinder engine having a plurality of cylinders arranged along the cylinder, the parallel multi-cylinder engine having a crankshaft and an intake air disposed in a cylinder head with an axial length direction substantially parallel to a vehicle width direction. A camshaft; an exhaust camshaft disposed substantially in front of the intake camshaft; and a variable valve timing mechanism including an actuator that changes a phase difference between the crankshaft and the intake camshaft. A rotation transmission mechanism for transmitting rotation of the crankshaft to the exhaust camshaft is provided on one side portion of the exhaust camshaft. An actuator of the variable valve timing mechanism is provided on the other side portion of the exhaust camshaft, and one of the frame portions is near the outside of one side end portion of the intake camshaft of the parallel multi-cylinder engine. The other end of the frame portion extends through the vicinity of the outside of the other side end portion of the intake camshaft.

  In such a configuration, the rotation transmission mechanism and the actuator of the variable valve timing mechanism are arranged separately on the left and right sides of the engine, so that the engine center of gravity can be equalized in the left-right direction. Further, the left and right frame portions of the main frame can be extended through the side of the rear portion of the cylinder head of the engine, that is, the side of the narrowed portion of the cylinder head. Therefore, the size in the width direction of the vehicle body can be reduced in the vicinity of the cylinder head.

  According to the present invention, in a parallel multi-cylinder engine for a motorcycle and a motorcycle including the same, it is possible to equalize the center of gravity in the left-right direction. Further, in the motorcycle including the parallel multi-cylinder engine according to the present invention, the size in the width direction of the motorcycle can be reduced in the vicinity of the cylinder head.

  Hereinafter, a parallel multi-cylinder engine according to an embodiment of the present invention and a motorcycle equipped with the same will be described in detail with reference to the drawings. FIG. 1 is a left side view of a motorcycle 1 equipped with a parallel multi-cylinder engine (hereinafter simply referred to as “engine”) E according to an embodiment of the present invention. Shows that of road sports type. In FIG. 1, the engine E and main body frames (a head pipe 6, a main frame 7, a pivot frame 8, and the like described later) are indicated by solid lines, and the others are indicated by two-dot chain lines. In addition, the concept of the direction used in the present embodiment will be described below as being the same as the concept of the direction as viewed from the rider R who rides on the motorcycle 1 shown in FIG.

  The motorcycle 1 includes a front wheel 2 and a rear wheel 3, and the front wheel 2 is rotatably supported by a lower portion of a front fork 5 that extends in a substantially vertical direction, and a bar-type steering handle 4 is attached to the upper portion of the front fork 5. It has been. The front fork 5 is fixed (supported) to a steering shaft (not shown) provided in parallel with the front fork 5, and the steering shaft is rotatably supported by a head pipe 6. Therefore, the rider R can turn the front wheel 2 in a desired direction by turning the steering handle 4 clockwise or counterclockwise.

  From the head pipe 6 to the left and right frame parts 7A and 7B (only the left frame part 7A is shown in FIG. 1; see FIGS. A main frame 7 is extended rearward, and a pivot frame (swing arm bracket) 8 is extended downward from a rear portion of the main frame 7. A pivot shaft 9 provided on the pivot frame 8 supports a front end portion of a swing arm 10, and a rear wheel 3 is rotatably supported on the rear end portion of the swing arm 10.

  A fuel tank 12 is provided above the main frame 7 and behind the steering handle 4, and a riding seat 13 is provided behind the fuel tank 12. An engine E is mounted below the main frame 7 between the left and right frame portions 7A and 7B. The engine E has four cycles of parallel four cylinders, and is a double overhead camshaft type (DOHC type) having camshafts 30 and 31 for intake and exhaust in the cylinder head 20 as will be described later. It is an engine (see FIG. 2). The output of the engine E is transmitted to the rear wheel 3 through a chain (not shown), and propulsion is applied to the motorcycle 1 by rotating the rear wheel 3. Further, an integrally formed cowling 19 is provided so as to cover the front portion of the motorcycle 1, that is, the head pipe 6, the front portion of the main frame 7, and the side portion of the engine E.

The rider R gets on the motorcycle 1 across the seat 13, grips the grip 4 </ b> A provided at the end of the steering handle 4, and steps on a step (not shown) provided near the rear of the engine E. Travel with a load. At this time, the knee R _{1 of the} rider R is located on the side of the cylinder head 20 and the cylinder head cover 21 of the engine E.

  FIG. 2 is a side view of the engine E shown in FIG. 1 as viewed from the right side, and mainly shows the configuration inside the chain tunnel 27 disposed on the right side of the engine E. 3 is a plan view showing a configuration when the engine E shown in FIG. 2 is viewed from the direction of the arrow III, and shows the configuration of the upper portion of the cylinder head 20 with the cylinder head cover 21 omitted. FIG. 4 is a side view of the engine E shown in FIG. 1 as viewed from the left side. The cylinder head 20 and the cylinder head cover 21 are partially broken to show the internal configuration.

As shown in FIG. 2, the cylinders C _{1 to} C ₄ included in the engine E are provided to be inclined forward by a predetermined angle. As shown in FIG. 3, four intake ports 20 </ b> A corresponding to the cylinders C _{1 to} C ₄ are provided at the rear portion of the cylinder head 20 so as to open obliquely rearward and upward. Four exhaust ports 20B are provided in the front part so as to open forward. As shown in FIG. 2, an intake camshaft 30 and an exhaust camshaft 31 are disposed on the upper portion of the cylinder head 20, and the intake camshaft 30 and the exhaust camshaft 31 are covered with a cam holder 21 </ b> A from above. ing. A cylinder head cover 21 is further covered from above the cam holder 21 </ b> A, and the cylinder head cover 21 is fixed to the cylinder head 20. Therefore, the intake camshaft 30 and the exhaust camshaft 31 are held so as to be sandwiched between the upper part of the cylinder head 20 and the lower part of the cam holder 21A.

  A cylinder block 22 that accommodates a piston (not shown) is connected to the lower portion of the cylinder head 20, and further provided along the left-right direction (the vehicle width direction of the motorcycle 1) at the lower portion of the cylinder block 22. A crankcase 23 that houses a crankshaft 32 that outputs rotation is connected. A right side wall portion (hereinafter referred to as “chain tunnel inner wall portion”) 27A of the cylinder head 20, the cylinder block 22, and the crankcase 23 has a chain tunnel outer wall portion 27B (a part of which is shown in FIG. Are connected and covered at the peripheral edge thereof. An internal space formed by the chain tunnel inner wall portion 27A and the chain tunnel outer wall portion 27B has a chain tunnel that accommodates a rotation transmission mechanism 28 including an exhaust cam sprocket 41, a crank sprocket 42, and a timing chain 50, which will be described later. 27. An oil pan 25 for storing lubricating oil is provided at the lower part of the crankcase 23, and an oil filter 26 for purifying the oil sucked up from the oil pan 25 is provided at the front of the crankcase 23. Yes.

  As shown in FIGS. 2 and 3, the intake camshaft 30 and the exhaust camshaft 31 provided at the upper part of the cylinder head 20 are both parallel to the crankshaft 32 in the axial length direction, and the motorcycle 1 is a vehicle. The exhaust camshaft 31 is disposed in parallel with the width direction so that the exhaust camshaft 31 is positioned in front of the intake camshaft 30. The right end portion of the exhaust camshaft 31 protrudes from the chain tunnel inner wall portion 27 </ b> A into the chain tunnel 27, and the exhaust cam sprocket 41 is rotatable at the end portion integrally with the exhaust camshaft 31. Is attached. Further, as shown in FIG. 2, the right end portion of the crankshaft 32 protrudes from the chain tunnel inner wall portion 27 </ b> A into the chain tunnel 27, and this end portion can be rotated integrally with the crankshaft 32. A crank sprocket 42 is attached to the main body.

  A timing chain 50 is wound around the exhaust cam sprocket 41 and the crank sprocket 42. When the crank sprocket 42 rotates, the exhaust cam sprocket 41 rotates in conjunction therewith. Accordingly, the rotation of the crankshaft 32 is transmitted to the exhaust camshaft 31 by the rotation transmission mechanism 28 including the exhaust cam sprocket 41, the crank sprocket 42, and the timing chain 50. In the engine E according to the present embodiment, the crankshaft 32 rotates clockwise in FIG. 2, and the timing chain 50, the exhaust cam sprocket 41, and the exhaust camshaft 31 also rotate clockwise.

  As shown in FIG. 2, a movable chain slack guide 51 and a fixed chain guide 52 are provided in the chain tunnel 27. The chain slack guide 51 extends in the vertical direction on the rear side of the timing chain 50, and its lower end is pivotally supported on the right wall portion of the crankcase 23 in the vicinity of the upper side of the crank sprocket 42, and its upper end is The exhaust cam sprocket 41 is located in the vicinity. The upper part of the chain slack guide 51 is urged forward by a tensioner 55 provided on the rear wall portion of the cylinder head 20, and the timing chain 50 is supported from the rear so that an appropriate tension is applied to the timing chain 50. Giving.

  A fixed chain guide 52 provided in the chain tunnel 27 extends in the vertical direction on the front side of the timing chain 50 and extends from a position near the front of the crank sprocket 42 to a position near the lower portion of the exhaust cam sprocket 41. Yes. The chain guide 52 supports the timing chain 50 from the front by a groove (not shown) formed in the rear part along the longitudinal direction. That is, the front portion of the timing chain 50 is accommodated in a groove formed in the rear portion of the chain guide 52, and the timing chain 50 moves along the groove.

  A drive gear 43 for outputting the rotation of the crankshaft 32 to a transmission (not shown) is provided in the crankcase 23 on the right side of the crankshaft 32 so as to be rotatable integrally with the crankshaft 32. It has been. A rear portion of the crankcase 23 is a transmission chamber (not shown), and a main shaft 34 is accommodated in parallel with the crankshaft 32. A driven gear 44 meshing with the drive gear 43 is provided at the right end of the main shaft 34 so as to be rotatable integrally with the main shaft 34. Therefore, when the engine E is operated, the rotation of the crankshaft 32 is transmitted to the main shaft 34 via the drive gear 43 and the driven gear 44, and is shifted by a transmission (not shown) and output to the rear wheel 3 (FIG. 1). .

  On the other hand, as shown in FIG. 3, the left part of the cylinder head 20 and the cylinder head cover 21 has a double wall structure composed of a gear accommodating chamber wall 60A and a gear accommodating chamber outer wall 60B. An internal space is formed between the gear housing chamber inner wall 60A and the gear housing chamber outer wall 60B, and this inner space serves as a gear housing chamber 60 for housing gears 63, 64 and the like to be described later. The left end portion of the intake camshaft 30 and the left end portion of the exhaust camshaft 31 protrude through the gear accommodating chamber wall 60A into the gear accommodating chamber 60. A driven gear 63 is attached to the left end of the intake camshaft 30 protruding into the gear housing chamber 60 so as to rotate integrally with the intake camshaft 30, and the left end of the exhaust camshaft 31. A drive gear 64 that rotates integrally with the exhaust camshaft 31 and meshes with the driven gear 63 is attached to the portion.

  A hydraulic actuator 66 is provided at the left end of the exhaust camshaft 31 and at the left side of the drive gear 64. Further, as shown in FIG. 4, the rear wall portion of the cylinder block 22 is connected to the hydraulic actuator 66 through an oil passage (not shown), and the flow rate or hydraulic pressure of oil supplied to the hydraulic actuator 66 is adjusted. An oil control valve 67 is provided. These hydraulic actuator 66 and oil control valve 67 constitute a variable valve timing mechanism 68.

  As shown in FIG. 3, the hydraulic actuator 66 has a cylindrical shape with a bottom and rotates integrally with the drive gear 64, and is accommodated in the housing 70 and rotates integrally with the exhaust camshaft 31. And a rotor 71. The hydraulic actuator 66 has a plurality of advance chambers and retard chambers (not shown) formed by the housing 70 and the rotor 71 in the housing 70. Oil sent through the oil control valve 67 and an oil passage (not shown) is sent to the advance chamber and retard chamber, and the phase difference between the housing 70 and the rotor 71 changes according to the flow rate or hydraulic pressure. To do.

  In such an engine E, when the crankshaft 32 rotates, the crank sprocket 42, the timing chain 50, and the exhaust cam sprocket 41 rotate, and the exhaust camshaft 31 rotates. That is, the exhaust camshaft 31 rotates in the same phase as the crankshaft 32. On the other hand, the rotation of the exhaust camshaft 31 is transmitted to the intake camshaft 30 via the hydraulic actuator 66 of the variable valve timing mechanism 68, and the exhaust camshaft depends on the oil flow rate or hydraulic pressure adjusted by the oil control valve 67. The intake camshaft 30 rotates with a predetermined phase difference with respect to the rotation of 31 (that is, rotation of the crankshaft 32). The phase difference between the crankshaft 32 and the intake camshaft 30 is changed by changing the oil flow rate or the oil pressure by the oil control valve 67.

  An exhaust cam sprocket 41 of the rotation transmission mechanism 28 is provided at the right end of the exhaust camshaft 31, and a hydraulic actuator 66 and a drive gear 64 of the variable valve timing mechanism 68 are provided at the left end. The balance in the left-right direction at the center of gravity of the engine E is equalized.

As shown in FIG. 3, in the engine E, four cylinders C _{1 to} C ₄ are arranged in order from the left, and in this embodiment, the center of this cylinder row (that is, the intermediate position between the cylinders C 2 and C 3) E ₁ A vehicle body centerline A that is the center of the engine E and connects the front wheel 2 and the rear wheel 3 of the motorcycle 1 passes through the center E _{1 of the} engine E. In the engine E, the left and right width dimensions of the cylinder head 20 are narrower at the rear than at the front. Hereinafter, the external shape of the cylinder head 20 will be described in detail. As described above, the exhaust cam sprocket 41, the drive gear 64, and the hydraulic actuator 66 are provided at both ends of the exhaust cam shaft 31, whereas the intake cam shaft 30 is driven by the left end thereof. A gear 63 is provided. The left and right sides of the intake camshaft 30 and the exhaust camshaft 31 are covered by the gear housing chamber outer wall portion 60B and the chain tunnel outer wall portion 27B.

  The outer wall portion 60B of the gear housing chamber has a convex shape in which a front portion 60C protrudes to the left side so as to cover the outside of the hydraulic actuator 66, while a rear portion 60D has a flat shape. The left end surface of the rear portion 60D is located closer to the right (that is, closer to the left and right centers of the motorcycle 1) than the left end surface of 60C. The chain tunnel outer wall portion 27B has a convex shape in which a front portion 27C projects rightward so as to cover the outside of the exhaust cam sprocket 41, while a rear portion 27D has a flat shape. The right end surface of the rear portion 27D is located closer to the left (that is, closer to the left and right centers of the motorcycle 1) than the right end surface of the front portion 27C.

  Therefore, the width of the rear portion of the cylinder head 20 is narrower than that of the front portion. The outside of the rear portion of the cylinder head 20, more specifically, the rear portion of the front portion 60C of the outer wall portion 60B of the gear housing chamber. Spaces 60E and 27E are formed in the vicinity of the left side of the rear portion 60D of the outer wall portion 60B of the gear storage chamber and in the vicinity of the right side of the rear portion 27D of the rear portion 27D of the chain tunnel outer wall portion 27B. Yes.

The left frame portion 7A of the main frame 7 passes above the hydraulic actuator 66 of the variable valve timing mechanism 68 and extends in the front-rear direction through the space 60E (FIGS. 1 to 1). 4). Further, the right frame portion 7B extends above the exhaust cam sprocket 41 of the rotation transmission mechanism 28 and extends in the front-rear direction through the space 27E (see FIGS. 1 to 4). As a result, the distance between the left and right frames 7A and 7B is relatively small. Thus, in the motorcycle 1, since the vehicle width of the vehicle body portion corresponding to the rear portion of the cylinder head 20 of the engine E decreases, taking the rider R boarding as knees R ₁ in the vicinity of the vehicle body part is located, A feeling of sitting improves.

  As shown in FIG. 4, when the engine E and the main frame 7 are viewed from the left side, the left frame portion 7 </ b> A of the main frame 7 has a lower end passing through substantially the same height as the center position of the intake camshaft 30. Extending substantially in the front-rear direction. Therefore, in the space 60E on the left side of the rear part of the cylinder head 20, a portion below the center position of the intake camshaft 30 is an extra space, and a sensor 75 for detecting the phase of the intake camshaft 30 is provided here. (See FIG. 3). That is, as shown in FIG. 3, the sensor 75 is attached to a lower portion of the rear portion 60 </ b> D of the gear housing chamber outer wall 60 </ b> B, and is a driven gear provided at the end of the intake camshaft 30 in the gear housing chamber 60. The phase of the intake camshaft 30 is determined by detecting a plurality of protrusions 63A (four in this embodiment: see FIG. 4) formed on the peripheral surface. To detect.

  The sensor for detecting the phase of the intake camshaft 30 may be attached to another part of the cylinder head 20, and FIG. 5 shows a part of the configuration of the engine E when the sensor is attached to the other part. 6 is a plan view showing the configuration when the engine E shown in FIG. 5 is viewed from the direction of the arrow VI, and shows the upper part of the cylinder head 20 with the cylinder head cover 21 removed.

  In the configuration shown in FIGS. 5 and 6, the chain tunnel outer wall portion 271 </ b> B is formed to be substantially parallel to the chain tunnel inner wall portion 271 </ b> A in substantially the entire range of the cylinder head 20 in the front-rear direction. A pulsar rotor 80 is provided to rotate integrally with the intake camshaft 30 at the right end of the intake camshaft 30 that protrudes into the chain tunnel 271 through the inner wall portion 271A of the chain tunnel. Yes. The pulsar rotor 80 has a plurality (four in the present embodiment) of protrusions 80A protruding in the diameter increasing direction, and the protrusions 80A are arranged at equal intervals along the circumferential direction. A sensor 81 is attached to the wall portion of the cylinder head 20 on the rear side of the chain tunnel 271. The sensor 81 detects the phase of the intake camshaft 30 by detecting the protrusion 80 </ b> A of the pulsar rotor 80 that rotates together with the intake camshaft 30. 5 and 6 with the same reference numerals used in FIGS. 1 to 4 are the same as those already described with reference to FIGS. Is omitted.

  In the above description, the configuration including the hydraulic actuator 66 and the oil control valve 67 as the variable valve timing mechanism 68 has been described as an example. However, the present invention is not limited to this, and for example, a variable valve timing configured using an electromagnetic actuator. A mechanism may be employed. Further, the engine E is not limited to four cylinders, and may be, for example, two cylinders or three cylinders. Furthermore, in the present embodiment, the timing chain 50 is wound between the exhaust cam sprocket 41 and the crank sprocket 42 and the rotation of the crankshaft 32 is transmitted to the exhaust camshaft 31. Instead of 41, an intake cam sprocket is provided at the right end of the intake camshaft 30, and a timing chain 50 is wound between the intake cam sprocket 42 and the crank sprocket 42 so that the rotation of the crankshaft 32 is transmitted to the intake camshaft 30. It may be.

  According to the parallel multi-cylinder engine of the present invention, it is possible to equalize the center of gravity in the left-right direction, and according to the motorcycle according to the present invention, in addition to the equalization of the center of gravity in the left-right direction, The vehicle width in the vicinity of the position can be narrowed, and the present invention can be applied to motorcycles and engines mounted thereon for various purposes.

1 is a left side view of a motorcycle equipped with a parallel multi-cylinder engine according to an embodiment of the present invention. It is the side view which looked at the engine shown in FIG. 1 from the right side, and has mainly shown the structure in the chain tunnel arrange | positioned at the right side of the engine. It is a top view which shows the structure when the engine shown in FIG. 2 is seen from a III arrow direction, and has a cylinder head cover abbreviate | omitted and has shown the structure of the upper part of a cylinder head. It is the side view which looked at the engine shown in FIG. 1 from the left side, and about the cylinder head and the cylinder head cover, the part is fractured | ruptured and the internal structure is shown. It is a right view which shows the structure of a part of engine when the sensor which detects the phase of an intake camshaft is attached to another part. FIG. 6 is a plan view showing the configuration when the engine shown in FIG. 5 is viewed from the direction of the arrow VI, showing the upper part of the cylinder head with the cylinder head cover removed.

Explanation of symbols

1 Motorcycle 4 Steering handle 7 Main frame 20 Cylinder head 28 Rotation transmission mechanism 30 Intake camshaft 31 Exhaust camshaft 32 Crankshaft 66 Hydraulic actuator (actuator)
68 variable valve timing mechanism 70 housing 71 rotor 75 and 81 sensors C ₁ -C ₄ cylinder E engine

Claims (5)

A parallel multi-cylinder engine for a motorcycle in which a plurality of cylinders are arranged along a vehicle width direction,
A crankshaft, an intake camshaft disposed in the cylinder head with an axial length direction substantially parallel to the vehicle width direction, an exhaust camshaft disposed substantially in front of the intake camshaft, A variable valve timing mechanism having an actuator that changes a phase difference between the crankshaft and the intake camshaft,
A rotation transmission mechanism for transmitting the rotation of the crankshaft to the intake camshaft or the exhaust camshaft is provided on one side of the cylinder head.
The parallel multi-cylinder engine for a motorcycle, wherein an actuator for the variable valve timing mechanism is provided on the other side of the cylinder head.   The rotation transmission mechanism is provided at one side portion of the exhaust camshaft, and the actuator included in the variable valve timing mechanism is provided at the other side portion of the exhaust camshaft. 2. A parallel multi-cylinder engine for a motorcycle according to 1.   The actuator of the variable valve timing mechanism includes a rotor that rotates integrally with the exhaust camshaft, and a housing that accommodates the rotor and rotates in conjunction with the rotor and rotationally drives the intake camshaft. The parallel multi-cylinder engine for a motorcycle according to claim 2, wherein the phase difference between the housing and the housing can be changed.   The sensor for detecting the phase of the intake camshaft is further provided on the side of the intake camshaft and behind the actuator of the variable valve timing mechanism or the rotation transmission mechanism. A parallel multi-cylinder engine for a motorcycle according to 2 or 3. A main frame composed of a pair of left and right frames extending substantially along the longitudinal direction of the vehicle body, and a parallel multi-cylinder engine mounted on the main frame and having a plurality of cylinders disposed along the vehicle width direction. Prepared,
The parallel multi-cylinder engine
A crankshaft, an intake camshaft disposed in the cylinder head with an axial length direction substantially parallel to the vehicle width direction, an exhaust camshaft disposed substantially in front of the intake camshaft, A variable valve timing mechanism having an actuator that changes a phase difference between the crankshaft and the intake camshaft,
A rotation transmission mechanism for transmitting rotation of the crankshaft to the exhaust camshaft is provided on one side portion of the exhaust camshaft,
An actuator of the variable valve timing mechanism is provided on the other side portion of the exhaust camshaft,
One of the frame portions extends through the vicinity of one side end portion of the intake camshaft of the parallel multi-cylinder engine, and the other side of the frame portion is the other side end portion of the intake camshaft. A motorcycle equipped with a parallel multi-cylinder engine, characterized by being extended through the outside of the vehicle.

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