JP4226196B2 - Valve operating system for 4-cycle engine for outboard motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve operating apparatus for a four-cycle engine for an outboard motor in which valve opening / closing timing is changed.
[0002]
[Prior art]
In recent years, there is a tendency to adopt a 4-cycle engine as an engine for an outboard motor mainly from the viewpoint of exhaust gas purification.
[0003]
By the way, in a four-cycle engine, an intake port and an exhaust port that open to a combustion chamber are opened and closed at appropriate timings by an intake valve and an exhaust valve, respectively, and necessary gas exchange is performed in each cylinder. By promoting the flow of exhaust, high charging efficiency is ensured and high output is achieved, and at low speeds, high combustion efficiency is ensured to achieve high output, low fuel consumption, and good exhaust gas characteristics. A valve operating apparatus in which the opening / closing timing of at least one of the valves is changed at a high speed and a low speed has been mainly adopted in an automobile engine. This valve operating device is provided with a variable valve timing mechanism at one end of a camshaft arranged in parallel with the crankshaft, and the valve opening / closing timing is changed by switching the oil pressure supplied to the variable valve timing mechanism with an oil control valve. It is something to be made.
[0004]
[Problems to be solved by the invention]
Thus, when the valve gear is applied to a four-cycle engine for an outboard motor, the amount of bubbles mixed in the oil supplied to each oil chamber of the variable valve timing mechanism depends on the arrangement and orientation of the oil control valve. Variations may occur and the operational stability of the variable valve timing mechanism may be hindered.
[0005]
The present invention has been made in view of the problem, and an object thereof is to provide a valve operating device for an outboard motor for a four-cycle engine capable of ensuring high operational stability in a variable valve timing mechanism. is there.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention rotates a camshaft arranged in parallel with a crankshaft arranged in a vertical direction by a crankshaft, and provides a variable valve timing mechanism at the upper end of the camshaft. In the valve operating apparatus for a four-cycle engine for an outboard motor, in which the opening / closing timing of the valve is changed by switching the hydraulic pressure supplied to the variable valve timing mechanism with the oil control valve, the oil control valve is connected to the variable valve timing mechanism. The oil passage and the oil groove that communicate with the oil control valve and the variable valve timing mechanism are located above a horizontal plane that passes through the central axis of the oil control valve. It is arranged .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0013]
First, the overall configuration of the outboard motor will be outlined with reference to FIG.
[0014]
FIG. 1 is a side view of a side view of the outboard motor 1. The outboard motor 1 is attached to a stern plate 100a of a hull 100 by a clamp bracket 2, and the clamp bracket 2 is supported by upper and lower damper members 3. A swivel bracket 5 that elastically supports the propulsion unit 4 is pivotally attached to a tilt shaft 6 so as to be rotatable up and down.
[0015]
Thus, the propulsion unit 4 has a housing composed of a cowling 7, an upper case 8 and a lower case 9, and an engine 10 is accommodated in the cowling 7. The engine 10 is supported by an exhaust guide 11, which is equipped with a valve gear according to the present invention.
[0016]
Incidentally, a crankshaft 12 (see FIG. 2) is arranged in the engine 10 in the vertical direction, and the crankshaft 12 is connected to an upper end of a drive shaft 13 that vertically cuts in the upper case 8. Yes. The lower end of the drive shaft 13 is connected to a forward / reverse switching mechanism 14 housed in the lower case 9, and a propeller shaft 15 extends horizontally rearward from the forward / backward switching mechanism 14. A propeller 16 is attached to the rear end portion that protrudes out of the lower case 9.
[0017]
Here, the configuration of the engine 10 will be described with reference to FIGS. 2 is a side sectional view of the engine portion of the outboard motor, FIG. 3 is a flat sectional view thereof, and FIG. 4 is a sectional sectional view of the same.
[0018]
The engine 10 is a water-cooled four-cycle four-cylinder engine, and is configured by arranging four cylinders in the vertical direction (vertical direction) as shown in FIG. The cylinder body 17 is provided with a cylinder 18 for each cylinder. Each cylinder 18 is fitted with a piston 19 that slides in the horizontal direction. Each piston 19 is connected to the crankshaft via a connecting rod 20. 12 is connected. The crankshaft 12 is long in the longitudinal direction (vertical direction in FIG. 2) in the crank chamber 21, and the reciprocating linear motion of each piston 19 is converted into the rotational motion of the crankshaft 12 by the connecting rod 20.
[0019]
By the way, the outboard motor engine 10 according to the present embodiment is a four-valve engine, and is provided with two intake valves 22 and exhaust valves (not shown) for each cylinder, and is a cylinder attached to the cylinder body 17. The head 23 has two intake ports 24 and exhaust ports (not shown) for each cylinder. The intake ports 24 and the exhaust ports (not shown) are opened and closed at appropriate timings by the intake valves 22 and the exhaust valves (not shown) driven by the valve gears according to the present invention. Necessary gas exchange is performed. An ignition plug 25 is screwed into the cylinder head 23 for each cylinder, and the cylinder head 23 is covered with a head cover 26.
[0020]
A throttle body 27 is disposed on the left side of the engine 10 as shown in FIG. 3, and a throttle valve 28 is built in each cylinder. A silencer 29 is connected to one end of the throttle body 27, and an intake manifold 30 that leads backward from the other end of the throttle body 27 is connected to the intake port 24 formed in the cylinder head 23. . Note that an intake port 29a formed at the front end portion of the silencer 29 opens inward. As shown in FIG. 4, the cylinder head 23 is provided with an injector 31 for each cylinder. A predetermined amount of fuel is injected from each injector 31 toward each intake port 24 at an appropriate timing. . In FIG. 3, 81 is a fuel rail and 82 is a fuel cooler.
[0021]
Here, the valve gear according to the present invention will be described.
[0022]
As shown in FIG. 2, each intake valve 22 is held by a cylinder head 23 so as to be slidable in the horizontal direction, and is urged toward the closing side by a spring 32 (see FIG. 5). Although not shown, each exhaust valve is also held by the cylinder head 23 so as to be slidable in the horizontal direction, and is biased toward the closing side by a spring.
[0023]
An intake cam shaft 33 and an exhaust cam shaft 34 (see FIG. 3) are parallel to the crankshaft 12 on the left and right sides of the cylinder head 23 (left and right in front of the outboard motor 1 (in the direction of arrow F in FIG. 2)). They are arranged in the vertical direction.
[0024]
The intake camshaft 33 has a plurality of journal portions rotatably supported by a plurality of bearing caps 35 and 36 (see FIG. 2), and two journal portions from the upper side are supported by a common bearing cap 35, The other journal portions are rotatably supported by a single bearing cap 36, respectively. Between each journal portion of the intake cam shaft 33, two intake cams 33a are integrally formed for each cylinder, and each intake cam 33a is a valve lifter 37 (see FIG. 5). Although not shown, the exhaust camshaft 34 is also integrally formed with two exhaust cams for each cylinder, and each exhaust cam 34 is in contact with a valve lifter covered at the end of each exhaust valve.
[0025]
Thus, in the outboard motor engine 10 according to the present embodiment, a variable valve timing mechanism (hereinafter abbreviated as VVT) 40 is provided at the upper end of the intake camshaft 33, and the intake air is absorbed by the VVT 40. The opening / closing timing of the valve 22 is controlled according to the engine speed.
[0026]
The VVT 40 is driven by hydraulic pressure, and oil of a predetermined pressure fed from an oil pump (not shown) is supplied to an oil passage 41 formed in the cylinder head 23 and an oil passage 42 formed in the bearing cap 35 ( 2), the oil is supplied to an oil control valve (hereinafter abbreviated as OCV) 43.
[0027]
Here, the OCV 43 is attached to the bearing cap 35, which is near the upper end of the intake camshaft 33, perpendicular to the intake camshaft 33 (horizontal), and within the full width of the engine 10. It arrange | positions in the left-right direction (left-right direction of FIG. 4). Therefore, the OCV 43 does not interfere with the cowling 7 when the cowling 7 is attached / detached, and the cowling 7 is attached / detached smoothly.
[0028]
The oil supplied to the OCV 43 is switched by the OCV 43 and supplied to the VVT 40 through the oil passage 44 or the oil passage 45 (see FIG. 5). As a result, the VVT 40 is driven and the intake valve 22 is driven as described above. The opening / closing timing is controlled.
[0029]
By the way, as shown in FIG. 3, sprockets 46, 47, 48 are respectively attached to the upper end portions of the crankshaft 12 and the intake / exhaust cam shafts 33, 34, and between these sprockets 46-48. An endless timing belt 49 is wound. 2 and 4, the OCV 43 is disposed below the lower surface of the intake-side sprocket 47. As shown in FIG.
[0030]
As shown in FIG. 2, a flywheel magneto 50 is attached to the upper end of the crankshaft 12, and the flywheel magneto 50, the sprockets 46 to 48, the timing belt 49, etc. on the upper part of the engine 10 also serve as a hula magnet cover. It is covered with a resin belt cover 51. Here, the lower part of the belt cover 51 is opened.
[0031]
On the other hand, the cowling 7 that covers the entire engine 10 is made of resin, and a space S defined by a resin plate 52 is formed in the upper rear part of the inside, and the space S is opened rearward. . And, in this space S, an air duct 52a erected integrally with the resin plate 52 is opened, and this air duct 52a is opposite to the VVT 40 in the left-right direction as shown in FIG. As shown in FIG. 2, it is disposed at a position that is offset forward (leftward in FIG. 2) from the VVT 40 in the front-rear direction.
[0032]
Thus, the outside air is sucked into the space S from the opening 7a that opens rearward to the upper part of the cowling 7, and passes through the space between the resin plate 52 and the belt cover 51 from the air duct 52a. As shown in FIG. 4, a rib 51a is integrally provided on the upper surface of the belt cover 51 so as to block the inflow of outside air to the intake side. As shown in FIG. 2, a rib 51b for restricting the forward flow of outside air is integrally formed on the upper surface of the belt cover 51.
[0033]
On the other hand, as shown in FIGS. 2 and 3, a space S ′ defined by the resin plate 53 is formed in the front portion of the cowling 7, and this space S ′ opens to the right as shown in FIG. ing. An air duct 54 having a large number of circular holes 54a is attached to the resin plate 53, and is sucked into the space S ′ from the opening 7b (see FIG. 3) that opens to the right side of the space S ′. The outside air thus introduced is introduced into the cowling 7 through the air duct 54.
[0034]
Thus, the outside air introduced into the cowling 7 is sucked from the intake port 29a (see FIG. 3) of the silencer 29, measured by the throttle valve 28 built in the throttle body 27, and then passed through each intake manifold 30. Then, the fuel flows through each intake port 24 of the cylinder head 23 and is mixed with fuel injected from the injector 31 in the middle thereof. Thus, an air-fuel mixture having a desired air-fuel ratio is formed, and this air-fuel mixture is used for combustion in each cylinder. The exhaust gas generated by the combustion of the air-fuel mixture is discharged into water through an exhaust passage (not shown) through an exhaust passage.
[0035]
Here, the detail of a structure of the said VVT40 provided in the valve gear which concerns on this invention is demonstrated based on FIGS. 5 is a sectional view around the VVT of the engine, FIG. 6 is a sectional view taken along line AA in FIG. 5, and FIG. 7 is a sectional view taken along line BB in FIG.
[0036]
As shown in FIGS. 5 and 6, the VVT 40 is configured by accommodating an output member 56 as a rotor concentrically and relatively rotatably inside an input member 55 as a housing. Here, the sprocket 47 is rotatably supported on the upper end of the intake camshaft 33, and the input member 55 of the VVT 40 is attached to the upper surface of the sprocket 47 by three bolts 57 (see FIG. 6), and an output member 56 As shown in FIG. 5, the intake camshaft 33 is fitted to the intake camshaft 33 by a bolt 58 that is fitted to the outer periphery of the upper end.
[0037]
As shown in FIG. 6, three vanes 56 a are integrally formed radially at an equal angular pitch (120 ° pitch) on the outer periphery of the output member 56, and each vane 56 a is formed on the inner peripheral surface of the input member 55. Oil chambers S1 and S2 are defined on the left and right sides of the seal chamber 59 by contacting with each other through the seal member 59.
[0038]
Cutout circular oil grooves 60 and 61 are respectively formed above and below the output member 56, and the upper oil groove 60 is provided in one oil chamber via oil holes 62 formed radially in the output member 56. The lower oil groove 61 communicates with the other oil chamber S <b> 2 through oil holes 63 formed radially in the output member 56.
[0039]
On the other hand, as shown in FIG. 7, the OCV 43 passes through the head cover 26 and is attached to the bearing cap 35 by an inlay, and the portion of the OCV 43 that passes through the head cover 26 has a diameter by a rubber lip seal member 64. The direction is sealed.
[0040]
Here, the OCV 43 is a solenoid valve, which is configured to house a rod 66 in a cylinder 65 so as to be able to advance and retract, and the rod 66 is urged in one direction by a spring 67. The rod 66 has large-diameter portions 66a and 66b that open and close oil holes 65a and 65b formed in the cylinder 65, respectively.
[0041]
Two oil passages 44 and 45 are formed in the bearing cap 35, and one end of each of these oil passages 44 and 45 communicates with the oil holes 65 a and 65 b formed in the cylinder 65 of the OCV 43. The ends of the oil groove 60 are formed in the output member 56 of the VVT 40 via oil grooves 68 and 69 formed on the outer periphery of the intake camshaft 33 and oil passages 70 and 71 formed in the intake camshaft 33 in the vertical direction. , 61 communicate with each other.
[0042]
Lubricating oil is supplied to the journal portion of the intake camshaft 33 from an oil passage 72 shown in FIG.
[0043]
Next, the operation of the valve gear according to the present invention having the above configuration will be described.
[0044]
When the engine 10 is started and the crankshaft 12 is driven to rotate, the rotation of the crankshaft 12 is transmitted to the VVT 40 and the exhaust camshaft 34 via the sprocket 46, the timing belt 49, and the sprockets 47 and 48, and the VVT 40 is input. The member 55 and the exhaust camshaft 34 are rotationally driven at a predetermined speed (1/2 speed of the crankshaft 12).
[0045]
When the exhaust cam shaft 34 is rotationally driven as described above, the exhaust valve is opened and closed at an appropriate timing by the exhaust cam formed on the exhaust cam shaft 34.
[0046]
In contrast, the rotation of the input member 55 of the VVT 40 is transmitted to the output member 56 through the oil in the oil chambers S1 and S2, and the output member 56 rotates integrally with the intake camshaft 33. When the intake camshaft 33 is driven to rotate, the intake valve 22 is opened and closed at an appropriate timing by the intake cam 33a formed on the intake camshaft 33, but oil is supplied to the oil chambers S1 and S2 in the VVT 40. By selectively supplying and rotating the output member 56 relative to the input member 55, the phase of the intake cam shaft 33 that rotates integrally with the output member 56 is changed, and the intake cam shaft 33 is formed on the intake cam shaft 33. The opening / closing timing of the intake valve 22 opened and closed by the intake cam 33a can be controlled.
[0047]
That is, as described above, the energization of the OCV 43 is turned ON / OFF and the rod 66 is moved forward and backward to selectively open and close the oil holes 65a and 65b of the cylinder 65, thereby switching the oil passages 44 and 45, not shown. The oil supplied from the oil pump to the OCV 43 through the oil passages 41 and 42 (see FIG. 2) is selectively passed through the oil passage 44 or the oil passage 45.
[0048]
Here, when oil flows into one of the oil passages 44, the oil flows through the oil groove 68 formed in the intake camshaft 33, the oil passage 70, and the oil groove 60 and oil hole 62 formed in the output member 56 of the VVT 40. Then, the oil is supplied to one oil chamber S1, and the output member 56 rotates relative to the input member 55 in the clockwise direction in FIG. When the oil flows into the other oil passage 45, the oil passes through the oil groove 69 formed in the intake camshaft 33, the oil passage 71 and the oil groove 61 formed in the output member 56 of the VVT 40 and the oil hole 63. Supplied to the other oil chamber S2, the output member 56 rotates relative to the input member 55 in the counterclockwise direction of FIG. Thus, when the output member 56 of the VVT 40 rotates relative to the input member 55, the phase of the intake camshaft 33 that rotates integrally with the output member 56 changes as described above. Timing is advanced or retarded.
[0049]
Thus, in the valve gear according to the present embodiment, since the OCV 43 is arranged at right angles (horizontal) to the intake camshaft 33 as described above, the oil supplied to the oil chambers S1, S2 of the VVT 40 As a result, the amount of bubbles mixed into the VVT 40 is made uniform, and high operating stability is ensured for the VVT 40.
[0050]
In the present embodiment, since the OCV 43 is disposed in the vicinity of the upper end of the intake camshaft 33, the distance between the VVT 40 provided at the upper end of the intake camshaft 33 and the OCV 43 is shortened, and the oil passage 44 connecting the two. , 45, 70, 71 are shortened, and the responsiveness of the VVT 40 is improved.
[0051]
Further, in the present embodiment, since the OCV 43 is disposed in the left-right direction within the entire width of the engine 10, the entire engine 10 can be made compact.
[0052]
In this embodiment, the variable valve timing mechanism (VVT) is provided only on the intake side to make the intake valve open / close timing variable. However, the variable valve timing mechanism (VVT) is provided on the intake and exhaust sides, respectively. -Needless to say, a valve operating device that makes the opening / closing timing of the exhaust valve variable is also included in the scope of application of the present invention.
[0053]
As is apparent from the above description, according to the present invention, the camshaft arranged in parallel with the crankshaft arranged in the vertical direction is driven to rotate by the crankshaft, and the variable valve timing mechanism is provided at the upper end of the camshaft. In the valve operating apparatus for a four-cycle engine for an outboard motor, the opening and closing timing of the valve is changed by switching the hydraulic pressure supplied to the variable valve timing mechanism by the oil control valve . A horizontal plane that passes through the central axis of the oil control valve through an oil passage and an oil groove that are disposed below the variable valve timing mechanism at a right angle to the cam shaft and communicates with the oil control valve and the variable valve timing mechanism. because it disposed above the supply to the oil chamber of the variable valve timing mechanism It is amount homogenization of bubbles mixed in the oil effect that high operating stability to the variable valve timing mechanism is ensured.
[Brief description of the drawings]
FIG. 1 is a side view of an outboard motor.
FIG. 2 is a side sectional view of an engine portion of an outboard motor.
FIG. 3 is a plan sectional view of an engine portion of an outboard motor.
FIG. 4 is a back cross-sectional surface of the engine portion of the outboard motor.
FIG. 5 is a sectional view around a variable valve timing mechanism of an outboard engine.
6 is a cross-sectional view taken along line AA in FIG.
7 is a cross-sectional view taken along line BB in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outboard motor 10 4-cycle engine 12 for outboard motor Crankshaft 22 Intake valve (valve)
33 Intake camshaft (camshaft)
33a Intake cam 34 Exhaust cam (cam shaft)
40 VVT (Variable valve timing mechanism)
43 OCV (oil control valve)

Claims (3)

The camshaft arranged in parallel with the crankshaft arranged in the vertical direction is rotationally driven by the crankshaft, and a variable valve timing mechanism is provided at the upper end of the camshaft, and the hydraulic pressure supplied to the variable valve timing mechanism is oiled. In the valve operating device for a four-cycle engine for an outboard motor that changes the opening and closing timing of the valve by switching with a control valve,
The oil control valve is disposed at a right angle to the camshaft below the variable valve timing mechanism ,
A four-cycle engine for an outboard motor , wherein an oil passage and an oil groove communicating the oil control valve and the variable valve timing mechanism are disposed above a horizontal plane passing through a central axis of the oil control valve. Valve gear. The operation of the 4-cycle engine for an outboard motor according to claim 1 , wherein the oil control valve is attached to the bearing cap through the head cover of the 4-cycle engine for the outboard motor. Valve device. The variable valve timing mechanism includes an output member in which a plurality of vanes are formed radially, and an input member that contacts the output member and defines an oil chamber. 2. A valve operating system for a four-cycle engine for an outboard motor according to 2.

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