variable valve timing system

Abstract

To provide a variable valve timing system that improves an operation accuracy of a variable valve device and enables an external pipe and a hydraulic pressure sensor to be installed properly.SOLUTION: A variable valve timing system is provided with: a variable valve device which changes an opening and closing timing of a valve by a hydraulic pressure; an oil control valve (40) configured to control a hydraulic pressure applied to the variable valve device; an external pipe (39) connecting a main gallery with the oil control valve; and a hydraulic pressure sensor (85) configured to detect a hydraulic pressure in an oil path formed at a crankcase. The oil control valve is installed on one side surface as seen in a vehicle width direction of the engine. One end portion of the external pipe is connected to one side as seen in the vehicle width direction of the main gallery. In a bottom view of a vehicle, the one end portion of the external pipe overlaps with the crankcase, and the hydraulic pressure sensor overlaps with the crankcase on one side as seen in the vehicle width direction relative to the one end portion of the external pipe.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a variable valve timing system. [Background technology]

[0002] Variable valve timing systems are being adopted to achieve high power output, low fuel consumption, and low exhaust gas emissions, in which the valve opening and closing timing is controlled by a variable valve timing mechanism depending on the engine's operating conditions. One known variable valve timing system controls the oil pressure for the variable valve timing mechanism using an oil control valve installed on the outer surface of the cylinder head (see, for example, Patent Document 1). An oil pressure sensor is installed midway in the oil passage leading from the oil supply source to the oil control valve, and detects the oil pressure supplied from the oil control valve to the variable valve timing mechanism. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5345448 Summary of the Invention [Problem to be solved by the invention]

[0004] While it is preferable to form the oil passage from the oil supply source to the oil control valve inside the crankcase, this has the disadvantage of increasing the crankcase size. In saddle-type vehicles, the engine size is limited by the body frame, so an external pipe is sometimes used to supply oil to the oil control valve. To ensure accurate operation of the variable valve train, a hydraulic pressure sensor is installed near the external pipe, but this does not adequately address issues such as bank angle and damage in the event of a fall.

[0005] The present invention has been made in view of the above points, and has an object to provide a variable valve timing system that improves the operating accuracy of a variable valve train and allows for appropriate installation of external piping and hydraulic sensors. [Means for solving the problem]

[0006] One aspect of the variable valve timing system of the present invention is a variable valve timing system for an engine in which a main gallery that is long in the vehicle width direction is formed in the crankcase, and the system comprises a variable valve train that changes the opening and closing timing of a valve using oil pressure, an oil control valve that controls the oil pressure for the variable valve train, an external pipe that connects the main gallery and the oil control valve, and an oil pressure sensor that detects the oil pressure in an oil passage formed in the crankcase, wherein the oil control valve is installed on one side of the engine in the vehicle width direction, one end of the external pipe is connected to one side of the main gallery in the vehicle width direction, one end of the external pipe overlaps the crankcase when viewed from below the vehicle, and the oil pressure sensor overlaps the crankcase on one side of the one end of the external pipe in the vehicle width direction. In a bottom view of the vehicle, the external piping extends from the main gallery to the front of the vehicle, and the connector of the oil pressure sensor faces the rear of the vehicle. This solves the above problem. [Effects of the Invention]

[0007] According to a variable valve timing system of one aspect of the present invention, high-pressure oil is supplied directly from the main gallery to the oil control valve through an external pipe, and the oil pressure near the external pipe is detected by the oil pressure sensor, thereby improving the operating accuracy of the variable valve timing device. By overlapping one end of the external pipe and the oil pressure sensor with the crankcase when viewed from below the vehicle, the external pipe and the oil pressure sensor can be installed in an appropriate position that takes into account factors such as bank angle and damage in the event of a fall. Furthermore, by positioning the oil pressure sensor to one side in the vehicle width direction, thermal damage to the oil pressure sensor from the engine can be reduced, and access to the oil pressure sensor is easier, improving maintainability. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a right side view of the front part of the vehicle according to the present embodiment. [Figure 2] FIG. 2 is a right side view of the engine and its surroundings according to the present embodiment. [Figure 3] FIG. 2 is a front view of the engine and its surroundings according to the present embodiment. [Figure 4] 2A and 2B are a front view and a rear view of the oil control valve of the present embodiment. [Figure 5] FIG. 2 is a schematic diagram of an oil passage according to the present embodiment. [Figure 6] FIG. 2 is a side view of the external piping and the hydraulic sensor installation location of the present embodiment. [Figure 7] FIG. 2 is a bottom view of the external piping and the hydraulic sensor installation locations of the present embodiment. [Figure 8] FIG. 2 is a schematic diagram of an oil passage inside the crankcase of the present embodiment. [Figure 9] 1 is a schematic diagram of a variable valve timing system according to an embodiment of the present invention; [Figure 10] FIG. 10 is a perspective view of a modified example of an oil pressure sensor. [Figure 11] FIG. 10 is a schematic diagram of an oil passage inside a crankcase of a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] A variable valve timing system according to one aspect of the present invention is mounted on an engine having a main gallery formed in the crankcase that is elongated in the vehicle width direction. The variable valve timing system includes a variable valve train that uses hydraulic pressure to change the valve opening and closing timing, and an oil control valve that controls the hydraulic pressure for the variable valve train. The main gallery and the oil control valve are connected by an external pipe, and high-pressure oil is supplied directly from the main gallery to the oil control valve through the external pipe. The hydraulic pressure in the oil passage formed in the crankcase is detected by a hydraulic pressure sensor, and detecting the hydraulic pressure near the external pipe with the hydraulic pressure sensor improves the operating accuracy of the variable valve train. The oil control valve is installed on one side of the engine in the vehicle width direction, and one end of the external pipe is connected to one side of the main gallery in the vehicle width direction. When viewed from below the vehicle, one end of the external pipe overlaps the crankcase, and the hydraulic pressure sensor overlaps the crankcase on one side of the external pipe in the vehicle width direction, allowing the external pipe and hydraulic pressure sensor to be installed in appropriate positions that take into account factors such as bank angle and damage in the event of a rollover. In addition, by positioning the hydraulic pressure sensor to one side in the vehicle width direction, thermal damage to the hydraulic pressure sensor caused by the engine can be reduced, and access to the hydraulic pressure sensor is made easier, improving maintainability. [Example]

[0010] This embodiment will be described in detail below with reference to the accompanying drawings. Fig. 1 is a right side view of the front of the vehicle of this embodiment. In the following drawings, arrow FR indicates the front of the vehicle, arrow RE indicates the rear of the vehicle, arrow L indicates the left side of the vehicle, and arrow R indicates the right side of the vehicle.

[0011] As shown in Fig. 1, the saddle-ride type vehicle 1 is configured by mounting an engine 21, an electrical system, and various other components on a twin-spar body frame 10. The body frame 10 has a pair of main frames 12 that branch off to the left and right from a head pipe 11 and extend rearward, and a pair of down frames 13 that extend downward from the front portions of the pair of main frames 12. The pair of main frames 12 pass above the engine 21 and curve around to the rear of the engine 21. The upper and rear sides of the engine 21 are suspended by the pair of main frames 12, and the front side of the engine 21 is suspended by the pair of down frames 13.

[0012] A front fork 14 is steerably supported on the head pipe 11 via a steering shaft (not shown). A front wheel 15 is rotatably supported on the lower part of the front fork 14. A radiator (heat exchanger) 16 that dissipates heat from the coolant for the engine 21 is provided in front of the engine 21. An upper part of the radiator 16 is supported on the main frame 12 via an upper bracket 17, and a lower part of the radiator 16 is supported on the engine 21 via a lower bracket 18. A cooling fan 19 is attached to the back of the radiator 16 to draw in hot air from the radiator 16 when the vehicle is stopped, etc.

[0013] The engine 21 is an in-line four-cylinder engine with four cylinders aligned laterally, and has a crankcase 22 that houses a crankshaft (not shown). A cylinder assembly, which is made up of a stack of cylinders 25, a cylinder head 26, and a cylinder head cover 27, is attached to the top of the crankcase 22. An oil pan 28 that stores oil for lubrication and cooling is attached to the bottom of the crankcase 22. Engine covers such as a clutch cover 31 and starter gear covers 32 and 33 are attached to the left side of the crankcase 22. Multiple exhaust pipes 34 extend downward from the front of the engine 21.

[0014] The engine 21 is equipped with a hydraulically controlled variable valve timing system that controls the opening and closing timing of intake valves (not shown). A variable valve train 60 (see FIG. 9) is housed inside the cylinder head 26 and cylinder head cover 27, and an oil control valve 40 is installed on the outer surface of the cylinder 25. The variable valve train 60 and the oil control valve 40 are connected via various oil passages within the engine 21. The oil control valve 40 controls the hydraulic pressure to the variable valve train 60, and the opening and closing timing of the intake valve is changed by the hydraulic pressure to the variable valve train 60.

[0015] In this type of engine 21, oil is supplied from the main gallery 38 of the crankcase 22 to the oil control valve 40 via an external pipe 39. In this case, the layout of the external pipe 39 must take into consideration factors such as bank angle, ground clearance, and risk of damage in the event of a fall. Also, while it is preferable to detect the oil pressure inside the external pipe 39 to control the variable valve timing, the bank angle and other factors must also be taken into consideration when determining where to install the oil pressure sensor 85. Furthermore, an oil pressure switch must be provided to monitor the oil pressure in each part of the engine 21.

[0016] Therefore, in the variable valve timing system of this embodiment, the external pipe 39 and oil pressure sensor 85 are installed by utilizing the dead space formed below the crankcase 22. The oil pressure sensor 85 detects the oil pressure in the oil passage inside the crankcase 22 near the inlet of the external pipe 39. As a result, not only is the oil pressure inside the external pipe 39 monitored to control the variable valve timing, but the oil pressure inside the engine 21 is also monitored to supply lubricating oil to various parts of the engine 21, eliminating the need to provide a separate oil pressure switch. Installing the oil pressure sensor 85 closer to one side in the vehicle width direction also improves maintainability.

[0017] The layout of the oil control valve will be described with reference to Figures 2 and 3. Figure 2 is a right side view of the engine and its periphery in this embodiment. Figure 3 is a front view of the engine and its periphery in this embodiment.

[0018] As shown in Figure 2, the crankcase 22 of the engine 21 has an upper and lower split structure including an upper case 23 and a lower case 24. Various shafts, such as the crankshaft, are supported on the mating surfaces of the upper case 23 and the lower case 24. An oil pan 28 is fixed to the underside of the lower case 24, and a cylinder 25 is fixed to the top surface of the upper case 23. A cylinder head 26 is fixed to the top surface of the cylinder 25, and a cylinder head cover 27 is fixed to the top surface of the cylinder head 26. The cylinder head 26 and crankcase 22 are suspended from the body frame 10.

[0019] The front portion of the body frame 10 branches into a main frame 12 and a down frame 13. The main frame 12 crosses the side of the cylinder head 26 diagonally from the top to the rear, and the down frame 13 is formed in a generally triangular shape in side view so that its front-to-rear width narrows downward. The main frame 12 covers the rear side of the cylinder head 26 from the sides, and the down frame 13 covers the front side of the cylinder head 26 from the sides. The rear side of the cylinder head 26 is suspended from a midpoint in the extension direction of the main frame 12, and the front side of the cylinder head 26 is suspended from the lower top of the down frame 13.

[0020] In a side view of the vehicle, a triangular area (region) is formed on the side of the cylinder head 26, surrounded by the lower edge of the main frame 12, the rear edge of the down frame 13, and the underside of the cylinder head 26. The triangular area of ​​the cylinder head 26 is exposed laterally between the main frame 12 and the down frame 13, but the triangular area is not large enough for the oil control valve 40. For this reason, the oil control valve 40 is installed on the right side surface (outer surface) of the cylinder 25, which is below the triangular area of ​​the cylinder head 26. The side surface of this cylinder 25 is formed by the outer wall of the cam chain chamber 58 (see FIG. 6).

[0021] A pair of plug caps 66, 67 are installed in a triangular region of the cylinder head 26 to close insertion openings for a pair of oil pipes 64, 65 (see FIG. 5), which will be described later. Because the plug caps 66, 67 avoid the body frame 10 in a side view of the vehicle, the oil pipes 64, 65 can be attached and detached via the plug caps 66, 67 even when the engine 21 is suspended from the body frame 10, improving maintainability. Because the plug caps 66, 67 are installed along the rear edge of the down frame 13, there is no need to modify the shape of the down frame 13. In this case, the plug cap 67 at the rear of the vehicle is positioned higher than the plug cap 66 at the front of the vehicle, and the plug caps 66, 67 partially overlap in the vertical direction, thereby narrowing the installation area for the plug caps 66, 67.

[0022] The oil control valve 40 is formed into a substantially cylindrical shape and includes a valve housing 41 that houses a valve spool (not shown) and a solenoid 42 that moves the valve spool back and forth. The solenoid 42 moves the valve spool back and forth, thereby switching the oil passage within the oil control valve 40. The oil control valve 40 is tilted so that its axial direction is parallel to the mating surface between the cylinder head 26 and the cylinder 25. The solenoid 42 is provided on the rear side of the valve housing 41 and is positioned higher than the valve housing 41.

[0023] Although there is a risk of contamination such as metal powder forming inside the valve housing 41, it is difficult for the contamination to get from the valve housing 41 into the solenoid 42. In other words, the oil control valve 40 is tilted so that the solenoid 42 is higher than the valve housing 41, which prevents the oil from carrying the contamination from the valve housing 41 to the solenoid 42. Because the contamination does not accumulate on the solenoid 42 side, the oil control valve 40 is prevented from being damaged by the contamination. Details of the oil control valve 40 will be described later.

[0024] Because the oil control valve 40 is installed on the outer surface of the cylinder 25, the oil control valve 40 does not interfere with the body frame 10 that suspends the cylinder head 26. Therefore, the body frame 10 does not protrude outward in the vehicle width direction, and an increase in the size of the saddle-ride type vehicle 1 is suppressed. Furthermore, because the center of gravity of the engine 21 is located in the crankcase 22, the oil control valve 40 is located close to the center of gravity of the engine 21. Therefore, transmission of vibration from the crankcase 22 to the oil control valve 40 is reduced, improving the durability of the oil control valve 40.

[0025] In a side view of the vehicle, the cylinder head 26 and cylinder 25 are fixed on either side of the cylinder axis by two bolts 36, and the cylinder 25 and crankcase 22 are fixed on either side of the cylinder axis by two bolts 37. The oil control valve 40 is installed so as not to overlap these four bolts 36, 37, preventing the oil control valve 40 from protruding outward in the vehicle width direction. In this case, the distance between the two upper bolts 36 is wider than the distance between the two lower bolts 37, and the oil control valve 40 is positioned closer to the cylinder head 26.

[0026] Starter gear covers 32, 33 that cover the starter gear (not shown) from the sides are provided below the oil control valve 40. A clutch cover 31 that covers the clutch (not shown) from the sides is provided behind the starter gear covers 32, 33. The upper part of the starter gear cover 32 protrudes toward the cylinder 25, but interference between the starter gear cover 33 and the solenoid 42 is minimized. Note that although the starter gear covers 32, 33 and the clutch cover 31 are formed as separate engine covers, the starter gear covers 32, 33 and the clutch cover 31 may also be formed as a single engine cover.

[0027] 2 and 3, the starter gear covers 32, 33 and the clutch cover 31 bulge outward in the vehicle width direction beyond the side surfaces of the cylinder 25. In a front view of the vehicle, the oil control valve 40 is positioned more inward in the vehicle width direction than the starter gear covers 32, 33, the clutch cover 31, and the down frame 13. In addition, the oil control valve 40 is positioned between the starter gear covers 32, 33 and the down frame 13. When the vehicle falls over, the oil control valve 40 is protected by the starter gear covers 32, 33, the clutch cover 31, and the down frame 13.

[0028] A main gallery 38 that is long in the vehicle width direction is formed below the crankcase 22. The main gallery 38 supplies oil from an oil pump (not shown) to various parts of the engine 21, such as journal bearings (not shown) of the crankshaft. The main gallery 38 and an oil control valve 40 are connected by an external pipe 39. One end (lower end) of the external pipe 39 is connected to the right side (one side in the vehicle width direction) of the main gallery 38, and the other end (upper end) of the external pipe 39 is connected to the oil control valve 40 that is installed on the right side of the engine 21 (cylinder 25).

[0029] Because oil for controlling valve timing requires high oil pressure, oil is supplied directly from the main gallery 38 to the oil control valve 40 through an external pipe 39. The oil is sent from the main gallery 38 to the oil control valve 40 without passing through an oil passage in the crankcase 22. This reduces pressure loss in the oil passage, and oil at high oil pressure is supplied to the oil control valve 40. The external pipe 39 may be made up of a pipe, or may be made up of a pipe and a tube.

[0030] In a side view of the vehicle, one end of the external piping 39 is fixed to the lower part of the crankcase 22 via a union bolt (see FIG. 2). The external piping 39 extends from the main gallery 38 towards the front of the vehicle, wraps around the crankcase 22 from below behind the exhaust pipe 34 and extends upward, and is bent towards the rear of the vehicle below the down frame 13. The other end of the external piping 39 is fixed to the oil control valve 40 via a union bolt. In this way, the external piping 39 is positioned below the down frame 13 on the right side of the engine 21. The shortening of the external piping 39 reduces pressure loss, improving the operating accuracy of the variable valve train 60 and making it easier to accommodate bank angles, etc.

[0031] When viewed from the front of the vehicle, engine covers such as starter gear covers 32, 33 and clutch cover 31 are attached to the right side of the crankcase 22 (see FIG. 3). An exhaust pipe 34 extends downward from the front surface of the cylinder head 26 above the crankcase 22, and one end (lower end) of an external pipe 39 is covered from the front by the exhaust pipe 34. The external pipe 39 protrudes from the back side of the exhaust pipe 34 to the right (one side in the vehicle width direction), and extends toward an oil control valve 40, passing between the various engine covers and the exhaust pipe 34.

[0032] Because the external piping 39 is located more inward in the vehicle width direction than the various engine covers, the external piping 39 is protected by the various engine covers and the down frame 13 in the event of the vehicle tipping over. Furthermore, one end of the external piping 39 is close to the road surface, but is protected by the exhaust pipe 34. Furthermore, the external piping 39 does not protrude to the right side from the various engine covers, and is separated from the exhaust pipe 34. The effect of heat from the exhaust pipe 34 on the external piping 39 is reduced, and the external piping 39 is cooled by the wind while traveling, so an increase in oil temperature in the external piping 39 can be suppressed.

[0033] An oil pressure sensor 85 is detachably mounted on the outer surface of the crankcase 22. The oil pressure sensor 85 detects the oil pressure in an oil passage formed in the crankcase 22. The oil pressure sensor 85 detects the oil pressure near one end of the external piping 39 and monitors the oil pressure in the external piping 39 to control the variable valve timing, as well as the oil pressure in the engine 21 to supply oil for lubrication to various parts of the engine 21. The oil pressure sensor 85 is located inward in the vehicle width direction from the various engine covers, and therefore is protected by the various engine covers and the down frame 13 if the vehicle rolls over.

[0034] A radiator 16 having a rectangular shape in front view is provided in front of the cylinder head 26. The radiator 16 is tilted so that its upper portion is positioned further forward than its lower portion. The radiator 16 is a round radiator that is curved in an arch shape in top view, and a cooling fan 19 is attached to the back of the radiator 16 on the oil control valve 40 side (right side) in the vehicle width direction. When viewed from the front of the vehicle, the oil control valve 40 is installed outside the radiator 16 in the vehicle width direction and below the down frame 13, so that the wind generated by traveling is less likely to be blocked by the radiator 16 and the down frame 13 in front of the oil control valve 40.

[0035] Because the oil control valve 40 is a solenoid valve, the oil control valve 40 is prone to heat generation when the solenoid 42 is energized. Therefore, the oil control valve 40 is cooled by the wind while the vehicle is running, which prevents deterioration in the operability of the variable valve mechanism 60 due to a rise in the temperature of the oil control valve 40 and the oil. As described above, the solenoid 42 is positioned on the rear side of the valve housing 41, and is separated from the radiator 16. Heat from the radiator 16 is less likely to be transmitted to the solenoid 42, which prevents a rise in temperature of the solenoid 42.

[0036] In a side view of the vehicle, the lower end of the down frame 13 is positioned on an extension line L extending from the lower end of the cooling fan 19 in the air blowing direction, and the oil control valve 40 is positioned below this extension line L. The exhaust air from the radiator 16 is less likely to hit the oil control valve 40, which prevents deterioration in the operability of the variable valve mechanism 60 caused by a rise in the temperatures of the oil control valve 40 and the oil. In addition, in a front view of the vehicle, the down frame 13 covers the solenoid 42 of the oil control valve 40, which blocks the exhaust air from the radiator 16 and prevents a rise in the temperature of the solenoid 42.

[0037] The oil control valve will be described with reference to Fig. 4. Fig. 4 shows a front view and a rear view of the oil control valve of this embodiment. Fig. 4(A) shows the front view of the oil control valve, and Fig. 4(B) shows the rear view of the oil control valve.

[0038] As shown in Figures 4(A) and 4(B), the valve housing 41 of the oil control valve 40 has a mounting plate 43 that is mounted on the side of the cylinder 25, and a cylindrical case 44 that bulges outward from the mounting plate 43. Fixing holes 45 for screwing are formed in three locations around the outer edge of the mounting plate 43 surrounding the cylindrical case 44. In addition, a supply port 46 to which the external piping 39 (see Figure 2) is connected is formed in the lower part of the mounting plate 43. A valve spool extending from the solenoid 42 is inserted into the cylindrical case 44. The destination of the oil that enters through the supply port 46 is switched by the valve spool.

[0039] An O-ring 47 is attached to the back surface of the mounting plate 43, sealing the gap between the back surface of the mounting plate 43 and the side surface of the cylinder 25. A supply port 46, an input port 51, an advance port 52, a retard port 53, and a drain port 54 are formed inside the O-ring 47. The supply port 46 is connected to the input port 51 through an oil passage formed in the cylinder 25. A filter 55 is installed in the input port 51, and the oil is filtered by passing through the filter 55. The input port 51 is connected to one of the advance port 52, retard port 53, and drain port 54, depending on the position of the valve spool.

[0040] When oil flows into the input port 51 from the supply port 46, the oil is filtered by the filter 55 of the input port 51 and then input into the cylindrical case 44. When the valve spool is moved by the solenoid 42, the input port 51 is connected to either the advance port 52 or the retard port 53, and the drain port 54 is connected to the other of the advance port 52 or the retard port 53. As a result, oil is supplied from the oil control valve 40 to either the advance chamber S1 or the retard chamber S2 of the variable valve mechanism 60 (see FIG. 9 ), which will be described later, and excess oil is discharged from the other of the chambers toward the oil control valve 40.

[0041] The oil passages in the engine will be described with reference to Fig. 5. Fig. 5 is a schematic diagram of the oil passages in this embodiment.

[0042] As shown in Figure 5, a cam chain chamber 58 is formed in the cylinder 25 and cylinder head 26 of the engine 21. A cam chain 59 is housed in the cam chain chamber 58, and the cam chain 59 is stretched over an intake cam sprocket 71 and an exhaust cam sprocket 81. An intake camshaft 72 is fixed to the intake cam sprocket 71, and an exhaust camshaft 82 is fixed to the exhaust cam sprocket 81. A crankshaft (not shown) is connected to the intake camshaft 72 and the exhaust camshaft 82 via the cam chain 59.

[0043] The intake camshaft 72 and the exhaust camshaft 82 are rotatably supported by a cam housing 91. The cam housing 91 is a support wall fixed to the cylinder head 26, and has an upper housing 92 that supports the upper halves of the camshafts 72, 82, and a lower housing 93 that supports the lower halves of the camshafts 72, 82. A variable valve train 60 is attached to one end of the intake camshaft 72 inside the cylinder head 26. The variable valve train 60 uses hydraulic pressure to advance or retard the intake camshaft 72, thereby changing the opening and closing timing of the intake valve (not shown).

[0044] An oil control valve 40 is installed on the outer surface (side surface) of the cylinder 25, which forms the outer wall of the cam chain chamber 58. The oil control valve 40 controls the oil pressure to the variable valve train 60. An advance passage 100 extends from an advance port 52 (see FIG. 4B) of the oil control valve 40 toward the variable valve train 60, and a retard passage 105 extends from a retard port 53 (see FIG. 4B) of the oil control valve 40 toward the variable valve train 60. Oil that advances the opening and closing timing of the intake valve flows through the advance passage 100, and oil that retards the opening and closing timing of the intake valve flows through the retard passage 105.

[0045] The advance passage 100 and retard passage 105 for hydraulic control enter the outer wall of the cam chain chamber 58 from the oil control valve 40. The advance passage 100 and retard passage 105 then flow from the cylinder 25 side toward the cylinder head 26 side, cross the cam chain chamber 58, and flow toward the variable valve mechanism 60 through the inner wall of the cam chain chamber 58. In this case, the outer wall of the cam chain chamber 58 is formed by the outer wall of the cylinder 25, the outer wall of the cylinder head 26, and the outer wall of the crankcase 22, while the inner wall of the cam chain chamber 58 is formed by the inner wall of the cylinder 25, the inner wall of the cylinder head 26, the inner wall of the crankcase 22, and the cam housing 91.

[0046] The outer wall and inner wall of the cylinder head 26 are connected by a pair of oil pipes 64, 65. The pair of oil pipes 64, 65 pass inside the cam chain 59 and cross the cam chain chamber 58. Because the oil pipes 64, 65 are installed detachably, the pair of oil pipes 64, 65 do not become an obstacle when assembling the cam chain 59. Because the pair of oil pipes 64, 65 are detachable, the pair of oil pipes 64, 65 can be inserted after assembling the cam chain 59 to the engine 21. This makes effective use of the dead space inside the cam chain 59.

[0047] In the outer wall of the cam chain chamber 58, the advance passage 100 and the retard passage 105 extend parallel to the cylinder axis from the outer wall of the cylinder 25 toward the outer wall of the cylinder head 26. In this case, the advance passage 100 is positioned on the front side, and the retard passage 105 is positioned on the rear side, with the retard passage 105 extending to a position higher than the advance passage 100. Between the outer wall and inner wall of the cam chain chamber 58, the advance passage 100 and the retard passage 105 extend perpendicular to the cylinder axis, passing inside the pair of oil pipes 64, 65. In this way, the pair of oil pipes 64, 65 form a crossing point of the advance passage 100 and the retard passage 105.

[0048] In the inner wall of the cam chain chamber 58, an advance passage 100 and a retard passage 105 extend parallel to the cylinder axis from the outer wall of the cylinder head 26 toward the cam housing 91. The advance passage 100 passes through the lower housing 93 and extends to a mating surface 151 between the lower housing 93 and the upper housing 92, and then passes through the mating surface 151 to connect to the advance groove 131 from the side. The retard passage 105 passes through the mating surface 152 between the cylinder head 26 and the lower housing 93 and extends to below the retard groove 132, and then passes through the lower housing 93 to connect to the retard groove 132 from below. The advance groove 131 and the retard groove 132 are connected to the variable valve train 60 via the intake camshaft 72.

[0049] In the cylinder 25 and the cylinder head 26, the advance passage 100 and the retard passage 105 are formed by a straight passage parallel to the cylinder axis and an orthogonal passage perpendicular to the straight passage. This reduces oil pressure loss in the advance passage 100 and the retard passage 105 and allows the advance passage 100 and the retard passage 105 to be easily machined into the cylinder 25 and the cylinder head 26. In the cylinder 25 and the cylinder head 26, the advance passage 100 and the retard passage 105 are aligned in parallel. This allows the advance passage 100 and the retard passage 105 to be close to each other in the front-to-rear direction, preventing the engine 21 from becoming larger.

[0050] A drain hole 109 (see FIG. 9 in particular) that connects to the drain port 54 (see FIG. 4B) of the oil control valve 40 is formed in the outer wall of the cam chain chamber 58 on the cylinder 25 side. The inner peripheral surface of the cam chain 59 is positioned below the drain hole 109, and oil is discharged from the drain hole 109 toward the cam chain 59. The oil that drops from the drain hole 109 is supplied to the cam chain 59, appropriately lubricating the meshing portions of the cam chain 59 with the intake cam sprocket 71 and the exhaust cam sprocket 81, improving the durability of the cam chain 59. In addition, no guides or complex machining are required to direct the oil toward the cam chain 59.

[0051] The installation structure of the external piping and oil pressure sensor will be described with reference to Figures 6 to 8. Figure 6 is a side view of the installation locations of the external piping and oil pressure sensor in this embodiment. Figure 7 is a bottom view of the installation locations of the external piping and oil pressure sensor in this embodiment. Figure 8 is a schematic diagram of the oil passage inside the crankcase in this embodiment.

[0052] 6 and 7, the starter gear cover 33 bulges outward in the vehicle width direction from the side surface of the crankcase 22, and the dead space below the starter gear cover 33 is used as installation space for the oil pressure sensor 85 and external piping 39. A plug cap 88 that closes one end of the main gallery 38 is installed in the lower portion of the starter gear cover 33. One end of the external piping 39 is connected from below to the main gallery 38 on the right side of the engine (one side in the vehicle width direction) where the oil control valve 40 is installed, and is located inside the plug cap 88 in the vehicle width direction.

[0053] A branch passage 123 (see FIG. 8) extends upward from one end of the main gallery 38, and is directed toward the journal bearing of the crankshaft. The oil pressure in the branch passage 123 is detected by an oil pressure sensor 85 above the plug cap 88. As seen from the side of the vehicle, the oil pressure sensor 85 is located above the main gallery 38, and one end of the external piping 39 is located below the main gallery 38. By placing the oil pressure sensor 85 and one end of the external piping 39 above and below the main gallery 38, it is easier to ensure the bank angle, etc., compared to when the oil pressure sensor 85 and one end of the external piping 39 are lined up in the vehicle width direction.

[0054] 7, when viewed from below the vehicle, one end of the external piping 39 overlaps the crankcase 22, and the oil pressure sensor 85 overlaps the crankcase 22 to the right (one side in the vehicle width direction) of one end of the external piping 39. The amount by which the external piping 39 protrudes outward in the vehicle width direction is reduced, and most of the oil pressure sensor 85 is contained within the crankcase 22 in the vehicle width direction, making it easier to respond to bank angles and the like and preventing damage when the vehicle rolls over. Because the oil pressure sensor 85 is installed closer to the right side of the crankcase 22, thermal damage to the oil pressure sensor 85 by the engine 21 is reduced, and the oil pressure sensor 85 can be easily attached and detached, improving maintainability.

[0055] Furthermore, when viewed from below the vehicle, the external piping 39 extends from the main gallery 38 toward the front of the vehicle, and the connector 86 of the oil pressure sensor 85 faces toward the rear of the vehicle. The external piping 39 extends diagonally forward so as to face outward in the vehicle width direction, and the oil pressure sensor 85 has its connector 86 facing diagonally rearward so as to face outward in the vehicle width direction. Even when wiring (not shown) is connected to the connector 86 of the oil pressure sensor 85, the wiring of the oil pressure sensor 85 and the external piping 39 extend in opposite directions. Therefore, the oil pressure of the external piping 39 can be accurately detected by bringing one end of the oil pressure sensor 85 close to one end of the external piping 39 without causing interference between the wiring of the oil pressure sensor 85 and the external piping 39.

[0056] As described above, one end of the external piping 39 is connected to the main gallery 38, and the other end of the external piping 39 is connected to the oil control valve 40. When viewed from below the vehicle, the oil pressure sensor 85 is located between one end and the other end of the external piping 39 in the vehicle width direction, and therefore the oil pressure sensor 85 does not protrude significantly outward in the vehicle width direction from the crankcase 22. The oil pressure sensor 85 is located rearward of the line N connecting one end and the other end of the external piping 39 in the front-to-rear direction, and therefore the installation spaces for the oil pressure sensor 85 and the external piping 39 are divided between the front and rear of the vehicle, which improves the degree of freedom in installing the oil pressure sensor 85 and the external piping 39 and makes it easier to accommodate bank angles, etc.

[0057] As shown in Figure 8, a branch passage 123 extends upward from one end of the main gallery 38, and a branch passage 124 extends downward from a position upstream of one end of the main gallery 38. The upper branch passage 123 is directed toward the journal bearing, and the lower branch passage 124 is directed toward the external piping 39. The oil pressure sensor 85 is installed in the crankcase 22 so that the detection surface 87 of the oil pressure sensor 85 is exposed within the branch passage 123. A recess 125 is formed in the wall surface of the branch passage 123, and the detection surface 87 of the oil pressure sensor 85 is positioned within the recess 125. In this way, the oil pressure near one end of the main gallery 38 is detected by the oil pressure sensor 85.

[0058] The detection surface 87 of the oil pressure sensor 85 is oriented in a direction perpendicular to the branch passage 123 at position P2, which is away from the intersection position P1 of the main gallery 38 and the branch passage 123. Oil flows from the main gallery 38 toward the branch passages 123 and 124, but because the direction of the oil flow in the branch passage 123 is perpendicular to the direction of the detection surface 87 of the oil pressure sensor 85, contaminants in the oil are less likely to adhere to the detection surface 87 of the oil pressure sensor 85. Because the connector 86 is oriented outward in the vehicle width direction, the oil pressure sensor 85 is easily removed from the crankcase 22, making it possible to periodically remove contaminants from the detection surface 87 of the oil pressure sensor 85.

[0059] The variable valve timing system will be described with reference to Fig. 9. Fig. 9 is a schematic diagram of the variable valve timing system of this embodiment.

[0060] As shown in Figure 9, a drive gear 155 for the cam chain 59 is provided below the oil control valve 40. A crankshaft (not shown) is connected to the drive gear 155 via a gear train. The lower part of the cam chain 59 is hooked onto the drive gear 155, and the upper part of the cam chain 59 is hooked onto the intake side cam sprocket 71 and the exhaust side cam sprocket 81. When the drive gear 155 rotates and the cam chain 59 moves around, the intake side camshaft 72 rotates integrally with the intake side cam sprocket 71, and the exhaust side camshaft 82 rotates integrally with the exhaust side cam sprocket 81.

[0061] The cam chain 59 is guided by a lever guide 156 and a chain guide 157. The cam chain 59 that is sent out from the drive gear 155 to the intake side cam sprocket 71 is guided by the lever guide 156, and the cam chain 59 that is pulled from the exhaust side cam sprocket 81 to the drive gear 155 is guided by the chain guide 157. Because slack occurs in the cam chain 59 that goes from the drive gear 155 to the intake side cam sprocket 71, a chain tensioner (not shown) presses the lever guide 156 against the cam chain 59, applying tension to the cam chain 59.

[0062] The intake valve and exhaust valve are opened and closed by the rotation of the intake camshaft 72 and the exhaust camshaft 82, but the timing of opening and closing the intake valve is changed by a variable valve timing system. The variable valve timing system is provided with a variable valve train 60 that changes the relative rotational phase of the intake camshaft 72 with respect to the crankshaft. The variable valve train 60 has a case 61 fixed to the intake cam sprocket 71 and an inner rotor 62 fixed to the intake camshaft 72. The inner rotor 62 is housed inside the case 61 so as to be able to rotate relative to the crankshaft.

[0063] A case 61 of the variable valve mechanism 60 is formed with a plurality of hydraulic chambers, and a plurality of vanes 63 extend radially outward from an inner rotor 62. A vane 63 of the inner rotor 62 is housed in each hydraulic chamber of the case 61, and each hydraulic chamber is divided by the vanes 63 into an advance chamber S1 and a retard chamber S2. When the volume of the advance chamber S1 expands due to hydraulic pressure, the inner rotor 62 rotates relatively to the case 61 toward the advance side, and the intake camshaft 72 is advanced. When the volume of the retard chamber S2 expands due to hydraulic pressure, the inner rotor 62 rotates relatively to the case 61 toward the retard side, and the intake camshaft 72 is retarded.

[0064] The variable valve train 60 is operated by hydraulic pressure from the oil control valve 40. Oil is supplied to the oil control valve 40 from the main gallery 38 (see FIG. 2) through external piping 39. Depending on the communication state between the ports of the oil control valve 40, the destination of the oil supplied from the oil control valve 40 is switched between the advance chamber S1 and the retard chamber S2 of the variable valve train 60. Oil is supplied to the advance chamber S1 from the oil control valve 40 through an advance passage 100, and oil is supplied to the retard chamber S2 from the oil control valve 40 through a retard passage 105.

[0065] As described above, the advance passage 100 and the retard passage 105 traverse the cam chain chamber 58 (see FIG. 6 ), and the oil pipes 64, 65 are used to traverse the cam chain chamber 58. The oil pipes 64, 65 are installed inside the cam chain 59 between the lever guide 156 and the chain guide 157. The oil pipes 64, 65 are lined up in the front and rear with a space between them in the vertical direction, which narrows the installation area for the oil pipes 64, 65 and allows the oil pipes 64, 65 to be installed inside the cam chain 59 with ample space between them. Even when the cam chain 59 is pushed in by the lever guide 156, the cam chain 59 does not interfere with the oil pipes 64, 65.

[0066] As described above, according to this embodiment, oil with a high oil pressure is supplied directly from the main gallery 38 to the oil control valve 40 via the external pipe 39, and the oil pressure near the external pipe 39 is detected by the oil pressure sensor 85, thereby improving the operational accuracy of the variable valve mechanism 60. As one end of the external pipe 39 and the oil pressure sensor 85 overlap the crankcase 22 when viewed from below the vehicle, the external pipe 39 and the oil pressure sensor 85 can be installed in an appropriate position that takes into consideration the bank angle, damage in the event of a fall, etc. Furthermore, as the oil pressure sensor 85 is positioned to the right, thermal damage to the oil pressure sensor 85 by the engine 21 can be reduced, and access to the oil pressure sensor 85 is made easier, improving maintainability.

[0067] In this embodiment, the direction of the detection surface of the hydraulic sensor is perpendicular to the direction of the oil flow in the branch passage to prevent contamination from adhering to the detection surface of the hydraulic sensor. However, it is difficult to sufficiently prevent contamination from adhering to the detection surface of the hydraulic sensor. If contamination adheres to the detection surface of the hydraulic sensor, the detection accuracy of the hydraulic sensor may be reduced. Therefore, as shown in a modified example in FIG. 10(A), a hydraulic sensor 161 with a mesh strainer 166 may be used.

[0068] 10(A), oil pressure sensor 161 has a sensor body 162 with a hexagonal head shape that can be gripped by a tool or the like, a connector 163 provided on one end of sensor body 162, and a detection portion 164 protruding from the other end of sensor body 162. A cylindrical strainer 166 is attached to the other end of sensor body 162 so as to surround detection portion 164. A coarse mesh 167 is formed on the tip surface of strainer 166, and a finer mesh 168 than the tip surface is formed on the outer circumferential surface of strainer 166. Such an oil pressure sensor 161 is preferably used in an oil passage that branches into a T-shape inside crankcase 22.

[0069] As shown in Figure 11, a branch passage 172 extends vertically from one end of a main gallery 171. The upper side of the branch passage 172 faces the journal bearing, and the lower side of the branch passage 172 faces the external piping 39. At an intersection P3 between the main gallery 171 and the branch passage 172, a recess 173 is formed in the outer peripheral surface of the branch passage 172 so as to face the main gallery 171. A detection surface 165 of the oil pressure sensor 161 is positioned within the recess 173, and the detection surface 165 of the oil pressure sensor 161 faces the main gallery 171. The oil pressure sensor 161 is provided with a strainer 166 that crosses the branch passage 172 and enters the main gallery 171.

[0070] The strainer 166 filters the oil in the main gallery 171, preventing contaminants from adhering to the detection surface 165 of the oil pressure sensor 161, and also filters the oil in the branch passage 172, preventing contaminants from entering the journal bearing. At this time, mesh 167 on the tip surface of the strainer 166 installed in the main gallery 171 is formed coarser than mesh 168 on the outer circumferential surface of the strainer 166 installed in the branch passage 172. As the oil flows from the main gallery 171 to the branch passage 172, the oil is filtered in stages by the meshes 167, 168. As a result, pressure loss in the passages is reduced and contaminants are effectively removed from the oil.

[0071] 10(B), mesh 176 may be formed only on the tip surface of strainer 175. In this case, mesh 176 is formed on the tip surface of strainer 175 installed in main gallery 171, and the outer circumferential surface of strainer 175 installed in branch passage 172 is open. Even with this configuration, it is possible to remove contaminants from the oil in main gallery 171 while suppressing pressure loss within the passage.

[0072] In this embodiment, the oil pressure sensor is not provided with a strainer, but it may be provided with a strainer. In this case, the detection surface of the oil pressure sensor is positioned in a recess in the branch passage, and the strainer is provided on the oil pressure sensor so as to protrude from this recess into the branch passage. This allows the strainer to filter the oil in the branch passage, preventing contaminants from adhering to the detection surface of the oil pressure sensor and preventing contaminants from entering the journal bearing.

[0073] In addition, in this embodiment, an in-line four-cylinder engine is exemplified as the engine, but the type of engine is not particularly limited.

[0074] Although a twin-spar frame is used as an example of the vehicle body frame in this embodiment, the type of vehicle body frame is not particularly limited as long as it is a vehicle body frame capable of suspending a cylinder head. For example, the vehicle body frame may be a cradle frame or a diamond frame.

[0075] Furthermore, in this embodiment, the oil control valve is installed on the right side of the engine, but the oil control valve may be installed on the left side of the engine.

[0076] In addition, although the oil control valve is installed on the outer surface of the cylinder in this embodiment, the oil control valve may be installed on the outer surface of the engine. For example, the oil control valve may be installed on the outer surface of the crankcase.

[0077] Furthermore, in this embodiment, a solenoid valve is used as an example of the oil control valve, but the type of oil control valve is not particularly limited as long as it is a valve that can control the oil pressure for the variable valve mechanism.

[0078] Furthermore, in this embodiment, the variable valve mechanism is provided on the intake camshaft, but it is sufficient that the variable valve mechanism is provided on at least one of the intake camshaft and the exhaust camshaft.

[0079] In this embodiment, the cross passage of the cam chain chamber is formed by a detachable oil pipe, but the cross passage of the cam chain chamber may be formed in any manner that allows oil to move between the inner and outer walls of the cam chain chamber. For example, the cross passage may be formed by protruding one of the inner and outer walls of the cylinder head toward the other.

[0080] In addition, in this embodiment, the advance passage and the retard passage are partially formed parallel to each other, but if the engine is large enough, the advance passage and the retard passage may be formed non-parallel to each other as a whole.

[0081] In addition, in this embodiment, the oil control valve is installed so as not to overlap the bolts on the outer surface of the cylinder, but the oil control valve may overlap the bolts as long as it does not protrude excessively from the outer surface of the engine.

[0082] Furthermore, in this embodiment, the oil pipe and the plug cap are formed as separate bodies, but the oil pipe and the plug cap may be formed as one body.

[0083] In addition, in this embodiment, the area surrounded by the lower surfaces of the main frame, down frame, and cylinder head is formed in a triangular shape, but the shape of the area surrounded by the lower surfaces of the main frame, down frame, and cylinder head is not particularly limited.

[0084] In addition, in this embodiment, the external piping extends from the main gallery toward the front of the vehicle and the oil pressure sensor connector faces toward the rear of the vehicle, but the oil pressure sensor connector may be oriented in the direction in which the external piping extends as long as there is no interference between the external piping and the wiring of the oil pressure sensor.

[0085] Furthermore, in this embodiment, one end of the external piping is covered from the front by the exhaust pipe when viewed from the front of the vehicle, but one end of the external piping may be exposed from the exhaust pipe when viewed from the front of the vehicle.

[0086] Furthermore, the variable valve timing system is not limited to the illustrated saddle-ride type vehicle, and may be employed in other types of saddle-ride type vehicles. A saddle-ride type vehicle is not limited to all vehicles in which a rider sits astride a seat, but also includes small scooter-type vehicles in which a rider does not sit astride a seat.

[0087] As described above, the variable valve timing system of this embodiment is a variable valve timing system for an engine (21) having a main gallery (38) formed in the crankcase (22) that is long in the vehicle width direction, and includes: a variable valve train (60) that changes the valve opening / closing timing using hydraulic pressure; an oil control valve (40) that controls the hydraulic pressure for the variable valve train; an external pipe (39) that connects the main gallery and the oil control valve; and an oil pressure sensor (85) that detects the hydraulic pressure in an oil passage formed in the crankcase. The oil control valve is installed on one side surface of the engine in the vehicle width direction, and one end of the external pipe is connected to one side of the main gallery in the vehicle width direction. In a bottom view of the vehicle, one end of the external pipe overlaps the crankcase, and the oil pressure sensor overlaps the crankcase on one side of the one end of the external pipe in the vehicle width direction. With this configuration, oil with a high hydraulic pressure is supplied directly from the main gallery through the external pipe to the oil control valve, and the oil pressure sensor detects the hydraulic pressure near the external pipe, thereby improving the operating accuracy of the variable valve train. By overlapping one end of the external piping and the oil pressure sensor with the crankcase when viewed from below the vehicle, the external piping and the oil pressure sensor can be installed in an appropriate position that takes into consideration the bank angle, damage in the event of a fall, etc. Also, by positioning the oil pressure sensor to one side in the vehicle width direction, thermal damage to the oil pressure sensor from the engine can be reduced, and access to the oil pressure sensor is made easier, improving maintainability.

[0088] In the variable valve timing system of this embodiment, when viewed from the bottom of the vehicle, the external piping extends from the main gallery toward the front of the vehicle, and the oil pressure sensor connector (86) faces toward the rear of the vehicle. With this configuration, even when wiring is connected to the oil pressure sensor connector, the extension directions of the oil pressure sensor wiring and the external piping are opposite. Therefore, the oil pressure of the external piping can be accurately detected by bringing one end of the oil pressure sensor and one end of the external piping close to each other without interfering with each other. In addition, the installation spaces for the oil pressure sensor and the external piping are separated into the front and rear of the vehicle, improving the installation flexibility of the oil pressure sensor and the external piping and making it easier to accommodate bank angles, etc.

[0089] In the variable valve timing system of this embodiment, the other end of the external piping is connected to the oil control valve, and when viewed from below the vehicle, the oil pressure sensor is located between one end and the other end of the external piping in the vehicle width direction and is located rearward of the straight line (N) connecting the one end and the other end of the external piping in the front-to-rear direction. With this configuration, the oil pressure sensor does not protrude significantly from the crankcase in the vehicle width direction. The installation spaces for the oil pressure sensor and the external piping are separated into the front and rear of the vehicle, improving the flexibility of installation of the oil pressure sensor and the external piping and making it easier to accommodate bank angles, etc.

[0090] In the variable valve timing system of this embodiment, the hydraulic sensor is located above the main gallery and one end of the external piping is located below the main gallery when viewed from the side of the vehicle. With this configuration, the hydraulic sensor and one end of the external piping are installed above and below the main gallery, which makes it easier to ensure the bank angle, etc., compared to when the hydraulic sensor and one end of the external piping are lined up in the vehicle width direction.

[0091] In the variable valve timing system of this embodiment, an engine cover (clutch cover 31, starter gear covers 32, 33) is attached to one side of the crankcase in the vehicle width direction, an exhaust pipe (34) extends downward from the front of the cylinder head above the crankcase, and one end of the external piping is covered from the front by the exhaust pipe when viewed from the front of the vehicle, and the external piping protrudes from the back side of the exhaust pipe to one side in the vehicle width direction and passes between the exhaust pipe and the engine cover toward the oil control valve. With this configuration, the one end of the external piping close to the road surface is protected by the exhaust pipe. In addition, the external piping is separated from the exhaust pipe without protruding from the engine cover to one side in the vehicle width direction. The effect of heat from the exhaust pipe on the external piping is reduced, and the external piping is cooled by the wind when the vehicle is running, thereby preventing an increase in oil temperature in the external piping.

[0092] In the variable valve timing system of this embodiment, a cylinder (25) is fixed onto the crankcase, a cylinder head (26) is fixed onto the cylinder, and the cylinder head is suspended from a body frame (10). The body frame has a main frame (12) that laterally covers the rear side of the cylinder head and a down frame (13) that laterally covers the front side of the cylinder head. The oil control valve is installed on the side of the cylinder, and the external piping is located below the down frame. With this configuration, the external piping extends from the main gallery of the crankcase on one side in the vehicle width direction to the oil control valve on the side of the cylinder. The shortened external piping reduces pressure loss and improves the operating accuracy of the variable valve timing system. Furthermore, the shorter external piping makes it easier to accommodate changes in bank angle, etc.

[0093] Although the present embodiment has been described, other embodiments may be made by combining the above-described embodiments and modifications in whole or in part.

[0094] Furthermore, the technology of the present invention is not limited to the above-described embodiments, and various changes, substitutions, and modifications may be made without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea. [Explanation of symbols]

[0095] 10: Body frame 12: Mainframe 13: Down frame 21: Engine 22: Crankcase 25: Cylinder 26: Cylinder head 31: Clutch cover (engine cover) 32: Starter gear cover (engine cover) 33: Starter gear cover (engine cover) 34: Exhaust pipe 38: Main Gallery 39: External piping 40: Oil control valve 60: Variable valve train 85: Oil pressure sensor 86: Connector

Claims

1. A variable valve timing system for an engine in which a main gallery long in the vehicle width direction is formed in a crankcase, a variable valve mechanism that changes the valve opening and closing timing using hydraulic pressure; an oil control valve that controls hydraulic pressure for the variable valve mechanism; an external pipe connecting the main gallery and the oil control valve; a hydraulic pressure sensor for detecting hydraulic pressure in an oil passage formed in the crankcase, The oil control valve is installed on one side of the engine in the vehicle width direction, One end of the external piping is connected to one side of the main gallery in the vehicle width direction, When viewed from below the vehicle, one end of the external pipe overlaps the crankcase, and the hydraulic pressure sensor overlaps the crankcase on one side in a vehicle width direction relative to the one end of the external pipe, A variable valve timing system characterized in that, when viewed from below the vehicle, the external piping extends from the main gallery toward the front of the vehicle and the connector of the oil pressure sensor faces toward the rear of the vehicle.

2. A variable valve timing system for an engine in which a main gallery long in the vehicle width direction is formed in a crankcase, a variable valve mechanism that changes the valve opening and closing timing using hydraulic pressure; an oil control valve that controls hydraulic pressure for the variable valve mechanism; an external pipe connecting the main gallery and the oil control valve; a hydraulic pressure sensor for detecting hydraulic pressure in an oil passage formed in the crankcase, The oil control valve is installed on one side of the engine in the vehicle width direction, One end of the external piping is connected to one side of the main gallery in the vehicle width direction, and the other end of the external piping is connected to the oil control valve, When viewed from below the vehicle, one end of the external pipe overlaps the crankcase, and the hydraulic pressure sensor overlaps the crankcase on one side in a vehicle width direction relative to the one end of the external pipe, A variable valve timing system characterized in that, when viewed from below the vehicle, the hydraulic pressure sensor is located between one end and the other end of the external piping in the vehicle width direction, and is located rearward of a straight line connecting the one end and the other end of the external piping in the front-to-rear direction.

3. A variable valve timing system for an engine in which a main gallery long in the vehicle width direction is formed in a crankcase, a variable valve mechanism that changes the valve opening and closing timing using hydraulic pressure; an oil control valve that controls hydraulic pressure for the variable valve mechanism; an external pipe connecting the main gallery and the oil control valve; a hydraulic pressure sensor for detecting hydraulic pressure in an oil passage formed in the crankcase, The oil control valve is installed on one side of the engine in the vehicle width direction, One end of the external piping is connected to one side of the main gallery in the vehicle width direction, When viewed from below the vehicle, one end of the external pipe overlaps the crankcase, and the hydraulic pressure sensor overlaps the crankcase on one side in a vehicle width direction relative to the one end of the external pipe, A variable valve timing system characterized in that, when viewed from the side of the vehicle, the hydraulic sensor is located above the main gallery and one end of the external piping is located below the main gallery.

4. an engine cover is attached to one side surface of the crankcase in the vehicle width direction; An exhaust pipe extends downward from the front face of the cylinder head above the crankcase, 4. The variable valve timing system according to claim 1, wherein, in a front view of the vehicle, one end of the external piping is covered by the exhaust pipe from the front, and the external piping protrudes from a rear side of the exhaust pipe to one side in the vehicle width direction, passing between the exhaust pipe and the engine cover and toward the oil control valve.

5. a cylinder fixed on the crankcase, a cylinder head fixed on the cylinder, and the cylinder head suspended from a vehicle body frame; the vehicle body frame includes a main frame that covers a rear side of the cylinder head from the side, and a down frame that covers a front side of the cylinder head from the side, 5. The variable valve timing system according to claim 1, wherein the oil control valve is installed on a side surface of the cylinder, and the external piping is located below the down frame.

Images