JP3329415B2 - 4 cycle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-stroke engine provided with a valve stop mechanism for holding an intake valve or an exhaust valve at a closed position or a variable valve timing mechanism for changing the opening / closing timing of a valve.

[0002]

2. Description of the Related Art Some four-stroke engines are provided with a valve deactivating mechanism capable of holding at least a part of a plurality of intake valves or exhaust valves in a closed position in accordance with the operation state of the engine (for example, a four-cycle engine). Japanese Patent Application No. 60-246041
No.). Further, there is a vehicle equipped with a variable valve timing mechanism for changing the opening / closing timing of an intake valve or an exhaust valve according to the operating state of an engine.

[0003]

By the way, recently,
In order to reduce the engine price, the above valve deactivation mechanism,
It is demanded that the engine including the variable valve timing mechanism and the engine not including the variable valve timing mechanism share parts such as the cylinder block and the cylinder head as much as possible.
On the other hand, the valve rest mechanism and the variable valve timing mechanism are generally driven by hydraulic pressure, and depending on the structure of an oil supply system such as an oil passage for supplying hydraulic pressure to each mechanism, a switching valve, and the like. In some cases, it may not be possible to meet the request for sharing parts.

[0004] The present invention has been made in view of the above-mentioned conventional circumstances, and has as its object to provide a four-stroke engine capable of sharing parts such as a cylinder block and a cylinder head.

[0005]

According to the first aspect of the present invention, a valve rest mechanism for holding a valve in a closed position is disposed between a camshaft and a valve shaft, and the valve shaft is provided at an end of the camshaft. In a four-cycle engine equipped with a variable valve timing mechanism for changing the opening / closing timing, the variable valve timing mechanism is provided in a side cover detachably provided on an end face of a cylinder head so as to cover an end of the camshaft. An outer end of the variable valve timing mechanism is supported by an outer end support of the side cover, and the valve rest mechanism is slidably disposed in a lifter guide hole of the cam carrier to control the operation of the cam shaft. A hydraulic drive type disposed in a valve lifter for transmitting the oil to a shaft, and an oil from an oil pump disposed in the vicinity of an oil pan is supplied to the valve stop mechanism, the variable valve First supplied to the timing mechanism, a second
The oil passage is common from the oil pump to the inlet of the side cover, and is branched into a first oil passage and a second oil passage within the side cover, and opens and closes the first and second oil passages. The first and second switching valves are disposed at a portion downstream of the branch portion and within the side cover, and a portion of the first oil passage downstream of the first switching valve is located inside the side cover. And formed in the cam carrier so as to extend in parallel with the camshaft and contact the lifter guide hole, and the downstream portion of the second switching valve of the second oil passage is variable from the outer end support portion of the side cover to the variable position. The valve timing mechanism is formed so as to communicate with an oil introduction passage formed in an outer end portion of the valve timing mechanism.

According to a second aspect of the present invention, in the first aspect, a third oil passage for supplying oil from the oil pump to a camshaft bearing portion is formed so as to pass through the inside of the cylinder head. And

[0007]

According to the first aspect of the present invention, the first and second oil passages are formed in common from the oil pump to the side cover inlet and branched into two inside the side cover. Since the first and second switching valves are disposed downstream of the branch, the oil passage structure is simple. In addition, at least a part of the first oil passage to the valve deactivating mechanism and a first switching valve for opening and closing the first oil passage are provided on a side cover disposed on an end face of the cylinder head, and a first switch to the variable valve timing mechanism is provided. (2) Since at least a part of the oil passage and the second switching valve for opening and closing the second oil passage are provided on the side cover, only the side cover has a different structure to provide a valve rest mechanism and a variable valve timing mechanism. It is possible to share parts such as a cylinder block, a cylinder head, a head cover, and the like between an engine that is not provided and an engine that is not provided.

The outer end of the variable valve timing mechanism is supported by a side cover, and the second oil passage can be communicated from an outer end support portion of the side cover to an oil passage formed in the outer end. Therefore, the structure of the oil passage to the variable valve timing mechanism is simple, and almost all of the second oil passage is formed in the side cover, which also makes it easy to share parts.

Further, since the first oil passage to the valve rest mechanism extends parallel to the camshaft and is in contact with the lifter guide hole, the structure of the first oil passage to the valve rest mechanism can be simplified.

According to the second aspect of the present invention, the third oil passage for lubricating the camshaft, which is always required regardless of whether or not the valve rest mechanism is provided, is formed so as to pass through the cylinder head. The cylinder head can have the same structure regardless of whether or not the above-mentioned valve rest mechanism and variable valve timing mechanism are provided, and from this point, parts can be shared.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 13 are views for explaining a four-stroke engine according to an embodiment (first embodiment) of the present invention. FIG. 1 is a front view of the engine of the present embodiment, and FIG. 2 is a right side intake valve thereof. FIG. 3 is a sectional front view showing a center intake valve portion, FIG. 4 is a sectional front view showing a left side intake valve and a left exhaust valve portion, and FIG. FIGS. 6 (a) and 6 (b) are plan views showing an intake cam carrier and an exhaust cam carrier, respectively, FIG. 7 is a sectional side view showing a hydraulic system, and FIG. FIG. 9 is a schematic cross-sectional plan view showing an exhaust port portion, FIG. 9 is a schematic diagram for explaining operation, FIG.
FIGS. 0, 11 and 12 show the valve deactivation mechanism, FIG.
3 is a hydraulic system diagram.

In FIG. 1, reference numeral 1 denotes a water-cooled four-cycle four-cylinder five-valve engine equipped with the apparatus of the present embodiment, and an oil pan 3 is mounted on a lower mating surface of a cylinder block 2 of the engine 1; A cylinder head 4 is fastened to the surface with a head bolt 4e, and a head cover 5 is mounted on the upper mating surface of the cylinder head 4, and a front end surface (the front surface in FIG. 1) of the cylinder head 4 and the head cover 5 is provided. A head side cover 6a is detachably mounted on the front end face of the cylinder block 2 respectively. As shown in FIG. 5, the head bolt 4e is provided between each cylinder and both ends in the cam shaft direction (front,
(The rear end), and ten bosses 4g protruding from the bottom wall 4d of the cylinder head 4 are fastened.

A piston 7 is slidably inserted into four cylinder bores (cylinders) 2a formed in parallel with the cylinder block 2, and the piston 7 is connected to a crankshaft 12 by a connecting rod 8. . The crankshaft 12 is supported by a crank bearing portion 12a formed on the cylinder block 2 and a crank bearing cap 12b detachably mounted on the crank bearing portion 12a.

A combustion chamber 4b is provided in a recess on a mating surface 4a of the cylinder head 4 on the cylinder block side. One side of the combustion chamber 4b around the cylinder axis A (left side in FIG. 8)
One center intake valve opening 9a located at the center in the cam axis direction (vertical direction in FIG. 8) and left and right (first and second) side intake valve openings 9b and 9c located on both sides of the center intake valve opening 9a. Are formed, and two left and right (first and second) are provided on the other side.
Exhaust valve openings 10a and 10b are formed. An ignition plug 25 is screwed into a portion of the combustion chamber 4b slightly shifted from the cylinder axis A to the exhaust side. As will be described later, intake air from the center intake valve opening 9a flows in the cylinder A axis direction. When viewed (see FIG. 8), the gas flows toward the electrode of the ignition plug 25.

The center, left and right side intake valve openings 9a, 9b and 9c and the left and right exhaust valve openings 10a and
10b is arranged along the inner peripheral edge of the cylinder bore 2a. Therefore, when seen in the camshaft direction, as is clear from FIGS. 2 to 4, the openings 9 b and 9 c for both side intake valves are
The opening 9 for the center intake valve is located near the cylinder axis A side.
“a” is located on the opposite side of the cylinder axis A (opposite the cylinder axis side). That is, as shown in FIG. 8, the distance L1 from the straight line B parallel to the cam axis passing through the cylinder axis A to the side intake valve openings 9b and 9c and the distance L2 from the center intake valve opening 9a are L2> L1.

The openings 9a to 9c, 10a, 10
b, the diameters Dic, Dis1, Dis2, De1, De2 of the portions (throat portions) where the valve heads 11d, 13c of the respective valves described later contact.
Is set to have a relationship of Dic> De1 = De2> Dis1 = Dis2, that is, a relationship of Dic: De1, De2: Dis1, Dis2 = large: medium: small. The center, left and right side intake valve openings 9a, 9b, 9c are set to 9a: 9b: 9c = 46: 27: 27 in terms of the ratio of the opening areas.

Center, left and right side intake valve openings 9
a, 9b and 9c are the center, left and right side intake valves 11
a, 11b and 11c are opened and closed by the valve head 11d, and the exhaust valve openings 10a and 10b are connected to the exhaust valves 13a and 1b.
It is opened and closed by the valve head 13c of 3b. The valve shafts 11e of the intake valves 11a to 11c and the exhaust valves 13
The valve shafts 13a and 13b are arranged so as to extend obliquely outward upward at a predetermined valve sandwich angle. In this case, the inclination angle θ1 between the axis B1 of the center intake valve 11a and the cylinder axis A, the left and right side intake valves 11b, 11c
The inclination angle between the valve axis B2 and the cylinder axis A is θ2, θ2
> Θ1. That is, the center intake valve 11a is on the left,
It is arranged more upright than the right side intake valves 11b and 11c.

The intake valves 11a to 11c and the exhaust valves 13a and 13b constitute retainers 14a and 14a mounted on the upper ends or intermediate portions of the valve shafts 11e and 13d and the bottom surface of the cam chamber C of the cylinder head 4. The valve springs 14 and 15 provided between the spring seat 4c and the bottom wall 4d urge the valve openings in the closing direction.
Note that a double coil spring is used for the valve spring 15 for the exhaust valve.

The intake valves 11a to 11c are connected to the intake camshaft 1
At 6, the exhaust valves 13a and 13b are driven to open and close by the exhaust camshaft 17, respectively. The intake camshaft 16 and the exhaust camshaft 17 extend parallel to each other in the direction perpendicular to the plane of FIG. 2 to FIG. 4, and the intake and exhaust camshafts 16 and 17 are detachably mounted in the cam chamber C. The intake and exhaust cam carriers 20 and 30 thus mounted and the intake and exhaust cam caps 28 and 29 removably mounted on the carriers 20 and 30 are rotatably supported.

The intake camshaft 16 and the exhaust camshaft 17 are mounted at the front ends (right end in FIG. 7) of the intake camshaft 16 and the exhaust camshaft 17 so as to be relatively rotatable.
The exhaust timing gears 36a and 36b are connected to a first intermediate gear 39a provided on the front end face of the cylinder head by an upper timing chain 38a.
The second intermediate gear 39b, which is coaxial and rotates together, is connected to the crank gear 37a of the crankshaft 12 by a lower timing chain 38b, and these are covered by the head side cover 6a and the block side cover 6b. The timing gears 36a, 36b
And the crank gear 37a have the same diameter.
9a has the same diameter as or smaller than the timing gear 36a, and the second intermediate gear 39b has a larger diameter than the crank gear 37a. Thus, the intermediate gears 39a, 39b
, The intake and exhaust timing gears 36
The rotation of the crankshaft 12 can be reduced to half and transmitted to the camshaft without increasing the diameters of a and 36b.

An intake / exhaust variable valve timing mechanism 41 for changing the opening / closing timing of the intake / exhaust valves is provided at the front end of the intake / exhaust camshafts 16 and 17.
42 are mounted. In the variable valve timing mechanisms 41 and 42, a cylinder case 43b is mounted outside a cylinder shaft 43a fixed to the front ends of the cam shafts 16 and 17, and a piston 43c is disposed between the two so as to be able to move forward and backward. Of structure. The cylinder shaft 43a
The support shaft (outer end) 43d is inserted into the
d is supported by the outer end support portion 6c of the head side cover 6a, and hydraulic oil is supplied to the piston 43c through an oil introduction passage 43e formed in the support shaft 43d.

The above-described variable valve timing mechanisms 41 and 42
Then, when the piston 43c is moved forward and backward by hydraulic pressure,
The relative angular positions (phases) of the timing gears 36a, 36b and the camshafts 16, 17 change, thereby changing the intake valve 1
1a to 11c and the opening / closing timing of the exhaust valves 13a and 13b change.

As shown in FIG. 6 (a), the intake cam carrier 20 has a rod shape extending in the cam axis direction, and has first bearing portions 20 formed at both ends in the cam axis direction.
d, a second bearing portion 20e formed between the left side intake valve and the center intake valve in each cylinder, and a third bearing portion 20f formed at the boundary between the cylinders. Part 2
The portions between 0d and 20f are integrally connected by guide bosses 20g and 20g. 20g of this guide boss
Center, left and right lifter guide holes 20a, 20b, 2
0c is formed so as to be coaxial with each of the valve shafts 11e of the intake valves 11a to 11c. In addition, each of the bearing portions 20d
The above-mentioned cam cap 28 is a cap bolt 2
8a and 28b.

In this case, the cap bolt 28b disposed outside the second bearing portion 20e (opposite the cylinder axis A) located between the cylinders has a length reaching the boss 4f formed on the cylinder head 4. (See FIG. 2).
Thus, when the cam cap 28 is fixed with the bolt 28b, the intake cam carrier 20 is fixed on the cylinder head 4 at the same time. The intake cam carrier 20 is also fixed to the boss 4f of the cylinder head 4 by fixing bolts 28c at the flange 20h formed at an appropriate position.

As shown in FIG. 6B, the exhaust cam carrier 30 has a rod shape extending in the cam axis direction, and has a cam bearing portion 30c formed adjacent to the right exhaust valve of each cylinder. The guide boss 3 is provided on the cam bearing 30c.
0d is integrally formed, and a portion between each of the cam bearing portions 30c and the guide boss portions 30d is integrally connected by a passage boss portion 30e. Guide boss 30
The left and right lifter guide holes 30a and 30b are formed in d. The cam cap 2 is mounted on the bearing 30c.
9 is fixed by cap bolts 29a and 29b.

In this case, the cap bolt 29a disposed inside each of the bearings 30c (on the cylinder shaft A side) is set to a length that reaches the boss 4f formed on the cylinder head 4. Thus, when the cam cap 29 is fixed with the bolt 29a, the exhaust cam carrier 30 is fixed on the cylinder head 4 at the same time. Further, a portion facing the position between the left and right exhaust valves of the passage boss portion 30d and a flange portion 30f formed at an axial end portion are also provided with fixing bolts 29.
The fixing member is fixed to a boss portion 4f formed on the cylinder head by c.

The lower part of FIGS. 6A and 6B shows a state where the cam caps of the intake and exhaust cam carriers 20 and 30 are removed, and the middle part shows a cross section of the intake and exhaust cam carriers 20 and 30. The upper part shows the planar state of the bottom wall 4d of the cylinder head 4 from which the intake and exhaust cam carriers 20, 30 have been removed.

The cam nose 1 of the intake camshaft 16
6a, the center intake valve 11a, and the right side intake valve 11c.
Between the center and right side intake valve deactivation mechanism 18
a and 18b are interposed, and an exhaust valve pause mechanism 19 is interposed between the cam nose 17a of the exhaust camshaft 17 and the left exhaust valve 13a. The operation of these intake and exhaust valve suspension mechanisms 18a, 18b, 19 is controlled by valve suspension control means (ECU) not shown. The left side intake valve 11b and the right exhaust valve 13b are not provided with a valve stop mechanism.
6. The exhaust camshaft 17 is always driven to open and close regardless of the operating range.

The center and right side intake valve deactivating mechanisms 18a and 18b are provided with a plunger 24 which moves forward and backward by hydraulic pressure in the center of the intake cam carrier 20 and the right side lifter guide holes 20a and 20c. , 21c are slidably inserted and arranged. In the left side lifter guide hole 20b, a normal lifter 21b whose upper end opening of the cylindrical body is closed by a pad 21k with which the intake cam nose 16a slides is slidably disposed. The upper end surface of the valve shaft 11e of the left side intake valve 11b is always in contact with the inner surface.

The center, right side lifters 21a, 21
c, as shown in FIGS. 10 to 12, the camshaft 16 is provided at the upper end opening of a cylindrical body having a partition wall 21d near the center in the axial direction.
The cam nose 16a has a pad 21e with which it slides. A boss is formed on the upper surface of the partition wall 21d, and a cylinder hole 21g is formed in the boss.
Are formed so as to be orthogonal to the axis of the lifter.
Both ends of this cylinder hole 21g are lifters 21a, 21c.
An opening is formed in an annular groove 21i formed on the outer peripheral surface of the, and an opening at one end is closed by a lid member 27 in an oil-tight manner. A slide hole 21 is formed in the partition wall 21d so as to be orthogonal to the cylinder hole 21g and coaxial with each of the intake valves.
The slide hole 21f faces the inner surface of the pad 21e.

The transmission member 2 is provided in the slide hole 21f.
A second rod portion 22a is slidably inserted, and a lower central portion of a flange portion 22b formed at a lower end of the transmission member 22 is in contact with an upper end surface of a valve shaft 11e of the intake valve. An urging spring 23 is interposed between the flange portion 22b and the partition wall 21d, so that the lifters 21a and 21c are connected to the cam nose 16a of the intake cam shaft 16.
Is urged to the position where it comes into sliding contact with.

The plunger 24 is inserted into the cylinder hole 21g.
Are slidably inserted. This plunger 24
Stopper 2 annularly protruded from the inner surface of cylinder hole 21g
1h, the forward end position is regulated by the locking ring 21j, and the retracted end position is regulated by the locking ring 21j.
6 is biased to the retracted end position.

The plunger 24 has an escape hole 24a having the same diameter as the slide hole 21f. The escape hole 24a is coaxial with the slide hole 21f when the plunger 24 is located at the retracted end. Has become. Further, the transmission surface 2 is provided on the bottom side of the plunger 24.
4b is formed flat, and this transmission surface 24b is formed when the intake valve is closed (the base circle of the intake camshaft 16 is
1e) when the plunger 24 is located at the forward end.
At a predetermined valve clearance.

The exhaust valve deactivating mechanism 19 has the same structure as the intake valve deactivating mechanisms 18a and 18b, except that the left and right exhaust lifters 31a and 31b and the exhaust camshaft 17 are disposed.
2 and 4, the camshaft 17 is offset so as to be deviated toward the cylinder shaft. Due to the offset, the opening speed of the exhaust valves 13a and 13b increases, and a high blowdown pressure can be used for scavenging.
The scavenging efficiency can be improved. The exhaust camshaft 1
7. Both the intake camshaft 16 rotates clockwise.

The above-mentioned valve rest mechanisms 18a, 18b, 1
9. The hydraulic pressure supply system to the variable valve timing mechanisms 41 and 42 is configured as shown in FIGS. That is, the oil in the oil pan 3 is sucked up by the oil pump 32 and filtered by the oil filter 33, and then the oil passages 33a to 33 formed in the cylinder block 2, the cylinder head 4, and the head side cover 6a.
c, from the switching valve 34, through the oil passages 33h and 33n, the center oil passage 33d, or 33i, 33o, and the side oil passage 33e, and through the center intake valve deactivating mechanism 1
8a or the right side intake valve deactivating mechanism 18b or from the switching valve 35 to the left exhaust valve deactivating mechanism 19 through the oil passages 33j, 33p and 33g.

The oil passage 33 of the cylinder block 2
A part of the oil a is the journal portion 44 of the crankshaft 12.
And the oil passage 33b of the cylinder head 4
A part of the oil passes through an oil passage 33f formed in the cylinder head 4, and the bearings 20d of the camshafts 16 and 17
20f and 30c, and a part of the oil in the oil passage 33c of the head side cover 6a is supplied to the variable valve timing mechanisms 41 and 42 via the switching valves 45 and 46.

Here, as shown in FIGS. 1 and 7, the oil passage from the oil pump 32 to the valve stop mechanism and the variable valve timing mechanism is a passage 33 in the cylinder block 2.
a, which is common to the passage 33b in the cylinder head 4, but is branched into three branch portions a, b, and c in an oil passage 33c formed in the head side cover 6a, and the switching valves 34, 35 , 45, 46 valve part 34
a, 35a, 45a, and 46a. Each of the switching valves is a valve that is inserted into each of the valve portions by a solenoid 34.
The connection to each passage is switched by moving forward and backward at b, 35b, 45b, and 46b.

Switching valves 34, 35 for the above-mentioned valve deactivation mechanism
Oil passages 33h, 33 from the valve portions 34a, 35a
i, 33j are the oil passages 33 in the cylinder head again.
n, 33o, 33p, and communicate with oil passages 33d, 33e, 33g in the cam carriers 20, 30.
The oil passages 33k, 33m from the valve portions 45a, 46a of the switching valves 45, 46 for the variable valve timing mechanism are supported by the support shafts of the variable valve timing mechanisms 41, 42 via the outer end support 6c of the head side cover 6a. 43d communicates with the oil introduction passage 43e.

The oil passages 33d, 33e on the intake side
In the intake cam carrier 20 in parallel with the cam shaft,
Further, they are formed so as to be in contact with the center lifter guide hole 20a and the right side lifter guide hole 20c, respectively, and to open in the oil groove 21i. In this case, the inclination angle θ of the center and side intake valves 11a and 11c with respect to the cylinder axis A.
1, θ2, and a position L2 perpendicular to the camshaft from the cylinder axis A.
L1 is different from the center lifter guide hole 20.
a and the right side lifter guide hole 20c have different inclination angles, and are shifted outward (in the direction opposite to the cylinder axis) and inward (toward the cylinder axis) in the direction perpendicular to the camshaft. As a result, the oil passage 33d communicates with the center lifter guide hole 20a and the oil passage 33e communicates with the right side lifter guide hole 20c only by forming the oil passages 33d and 33e through the intake cam carrier 20 in parallel with the cam shaft. It can be formed to communicate.

Here, the oil passage 33e communicates with the left side lifter guide hole 20b. The normal lifter 21 is inserted into the left side lifter guide hole 20b.
b is slidably inserted, and the hydraulic pressure is applied to the lifter 21.
It hardly escapes from the gap between the guide hole 20b and the guide hole 20b, and no problem occurs.

The exhaust-side oil passage 33g is formed in the exhaust cam carrier 30 so as to open in the oil groove 21i in parallel with the cam shaft and in contact with the left lifter guide hole 30a. This exhaust-side oil passage 3
Although 3g also communicates with the right lifter guide hole 30b, almost no hydraulic pressure escapes as in the intake side.

The exhaust valve openings 10a and 10b are led to the external connection opening 47c of the cylinder head 4 by the left and right branch ports 47a and 47b of the exhaust port 47. In this case, the picture wall 47d of the left and right branch ports 47a and 47b may extend to the vicinity of the external connection opening 47c as shown by a two-dot chain line in FIG. With this extension,
As described later, the exhaust efficiency when the left exhaust valve 13a is at rest can be improved.

The center intake valve opening 9a and the side intake valve openings 9b, 9b are connected to the center branch port 48a of the intake port 48, the left and right side branch ports 48b, 48, respectively.
c leads to the external connection opening 48d of the cylinder head 4. Here, the right drawing wall 48f on the right side branch port 48c side is replaced with the left drawing wall 48e on the left side branch port 48b side.
It is greatly extended further upstream. This is to realize stratified combustion, as described later.

A fuel injection valve 50 is provided on the top wall of the intake manifold 49 connected to the external connection opening 48d. When viewed in the cylinder axial direction (see FIG. 8), the fuel injection valve 50 is located substantially on an extension of the left image wall 48e, and the injection nozzle 50a is connected to the intake port 4
8 is directed so as to inject fuel into the center intake valve opening 9a and the left side intake valve opening 9b through the injection hole 48f formed in the top wall of the fuel cell 8.

Next, the operation and effect of the first embodiment will be described. In the present embodiment, the variable valve timing mechanism 41,
The opening / closing timing of the intake valve and the exhaust valve is controlled by 42, and the valve suspension of the intake valve and the exhaust valve is controlled by the valve suspension mechanisms 18a, 18b, and 19.

First, in the variable valve timing mechanism 41 or 42, the switching valve 45 or 46 applies hydraulic pressure to the piston 4
3c, the piston 43c moves to the left in FIG. 7, and the timing gears 36a,
Or 36b and the phase of the intake camshaft 16 or the exhaust camshaft 17 change, and the intake valves 11a to 11c or the exhaust valve 13
The opening / closing timing of a and 13b changes.

In the valve stop mechanisms 18a and 18b, when the switching valve 34 is at the stop release position shown by the solid line in FIG. 13, the hydraulic pressure is applied via the oil passages 33d and 33e to the center intake valve stop mechanisms 18a and 18b. It is supplied to the right side intake valve suspension mechanism 18b. Then, as shown in FIG. 10, the plunger 24 moves forward by the action of hydraulic pressure to close the slide hole 21f, and the transmission surface 2 of the plunger 24
4b faces the upper end surface of the transmission rod 22a of the transmission member 22. When the center and right side lifters 21a and 21c are pushed down by the rotation of the camshaft 16, the operation is transmitted to the center and right side intake valves 11a and 11c via the plunger 24 and the transmission member 22, and the both intake valves 11a and 11c are transmitted.
c performs a normal opening and closing operation.

In the valve stop mechanism 19, the switching valve 3
13 is in the rest release position shown by the solid line in FIG.
Hydraulic pressure is supplied to the right exhaust valve deactivating mechanism 19 via the oil passage 33g, and the left exhaust valve 13
a performs a normal opening and closing operation. The left side intake valve 11b and the right exhaust valve 13b always open and close.

Then, the switching valve 3 for switching the valve stop is provided.
4 is switched to the rest position shown by the broken line in FIG.
The hydraulic pressure in the oil passages 33d and 33e decreases, and as shown in FIG. 11, the plunger 24 is returned to the retracted end position by the return spring 26, and the escape hole 24a of the plunger 24 is released.
Correspond to the slide hole 21f, that is, the transmission rod 22a. Rotation of the camshaft 16 causes the center and right side lifter 2
When 1a, 21c is pushed down, as shown in FIG. 12, the transmission rod 22a relatively enters into the escape hole 24a, and the lowering operation of the lifter is transmitted to the center and the right side intake valves 11a, 11c. Therefore, both intake valves 11a and 11c are in a valve stop state and are kept in the closed position.

If the intake valves 11a and 11c are completely closed during the valve rest operation, the fuel accumulated in the center and right side branch ports 48a and 48c may be carbonized and adhere to the inner surfaces of the ports. In this embodiment, even when the lifters 21a and 21c are lowered to the maximum lift position even in the valve rest state, the pad 21
The lower surface of e slightly pushes down the transmission rod 22a, whereby the intake valves 11a and 11c are slightly opened.

In the valve stop mechanism 19, the switching valve 3
5 is switched to the rest position shown by the broken line in FIG.
The oil pressure in the oil passage 33g decreases, and the left exhaust valve 13a is brought into a valve rest state in the same manner as described above, and is held at the closed position. In addition, also in this left exhaust valve 13a,
It may be opened slightly when the valve is stopped.

In the small intake air amount operation range such as at the time of low speed rotation or low load operation, the switching valves 34 and 35 are switched to the rest positions indicated by broken lines in FIG. 13 by the switching signal from the ECU. Thereby, the oil passages 33d, 3d
As shown in FIG. 9A, the center, the right side intake valves 11a and 11c, and the left exhaust valve 13a are in a valve rest state, and the left side intake valve is turned off, as shown in FIG. Only the valve 11b and the right exhaust valve 13b open and close.

As a result, the intake air has a small diameter of Dis1 and a small distance L1 in the direction perpendicular to the camshaft from the cylinder axis A, is closer to the cylinder axis side, and is located on one side in the camshaft direction. Concentrated from the intake valve opening 9b flows into the cylinder. As a result, the actual intake passage area is reduced, the inflow speed into the cylinder is increased while the amount of intake air is small, and the inflow direction is clarified. In-cylinder flow, especially swirl, is generated, and the combustion state is improved. As a result, the stability of lean air-fuel ratio combustion can be improved.

In this case, the left side intake valve 11b,
Since only the right exhaust valve 13b opposed to the ignition plug 25 (cylinder axis A) is opened / closed, the intake air flowing from the left side intake valve opening 9b is interposed between the ignition plug 25 and the ignition plug 25 after combustion. The exhaust gas is discharged from the opening 10b for the right exhaust valve located at the opposite position, that is, the flow of the exhaust gas passes through the center of the combustion chamber, so that the exhaust gas discharge efficiency is improved. By the way, when only one intake valve and one exhaust valve are opened and closed, the left side intake valve 1
When the opening / closing operation of the left exhaust valve 1a and the left exhaust valve 13a is performed, there is a concern that exhaust gas stagnates in the combustion chamber and the exhaust efficiency is reduced.

In order to discharge the exhaust gas more reliably, it is effective to extend the picture wall 47d of the exhaust port 47 to the vicinity of the external connection opening 47c as shown by a two-dot chain line in FIG. In this case, the flow of the above-mentioned exhaust gas is further smoothed, and the exhaust efficiency is improved. Incidentally, when the image wall 47d is not extended, when only the right exhaust valve 13b is operated, the right exhaust branch port 4 is used.
Since the passage area of the passage 7b substantially sharply increases and exhaust gas stagnates on the left exhaust branch port 47a side, there is a concern that the exhaust efficiency is reduced.

In a middle intake air amount operation range such as at the time of middle speed rotation or middle load operation, the switching valve 34 is held at the valve rest position (the broken line position in FIG. 13) with respect to the oil passage 33d by the switching signal from the ECU. , Oil passage 33e
Is switched to the pause release position (solid line position in FIG. 13), and the switching valve 35 is switched to the pause release position indicated by the solid line in FIG. As a result, as shown in FIG. 9B, only the center intake valve 11a is in a valve rest state, and the left and right side intake valves 11b and 11c and the left and right exhaust valves 13a and 13b open and close. Become.

As a result, the intake air has a small distance L1 in the direction perpendicular to the camshaft from the cylinder axis A, and is closer to the cylinder axis side, and the two left and right side intake valve openings 9b and 9c located on both sides in the camshaft direction. From the cylinder. As a result, the intake air flow into the cylinder is directed more along the cylinder axis as a result of the above-described swirl components canceling each other,
In-cylinder flow, particularly tumble, is reliably generated, and the combustion state is improved. As a result, the stability of lean air-fuel ratio combustion can be improved. In this case, in this embodiment, the center intake valve 11a has a large diameter and the left and right side intake valves 11b and 11c
, The distance L1 in the direction perpendicular to the camshaft is further reduced from this point, that is, the openings 9b and 9c for the left and right side intake valves are closer to the cylinder axis A side and further outward in the camshaft direction. As a result, the orientation in the cylinder axis direction becomes more reliable.

In a large intake air amount operation range such as a high-speed rotation operation or a high-load operation, the switching valve 34 is also switched to the rest release position in the oil passage 33d by the switching signal from the ECU. The valve pause operation is released, and all the intake valves and exhaust valves open and close.

As a result, the intake air flows into the cylinder through the center, left and right side intake valve openings 9a to 9c. In this case, in the intake port 47, for example, a conventional intake control valve is provided. Since there is no such a flow path resistance as described above, the maximum intake air amount can be increased.

In this embodiment, the right picture wall 48f extends toward the fuel injection valve 50, and the fuel injection valve 50 is arranged close to the left picture wall 48e. The intake air from the openings 9a and 9b is a mixture of fuel and air, whereas the intake air from the right side intake valve opening 9c is air alone containing almost no fuel. As a result, the air-fuel mixture containing fuel and the air alone flow into the combustion chamber in a stratified manner, and so-called stratified combustion can be realized.

FIG. 22 is an engine speed-torque characteristic curve for explaining the effect of improving the torque by the valve stop operation of the apparatus of this embodiment. In the figure, curves A, B, and C represent the small, medium, and 4 conceptually shows a torque characteristic in a large intake air amount operation range.

In the present embodiment, the intake cam carrier 20 and the exhaust cam carrier 30 which are detachable from the cylinder head 4 are provided as a structure for realizing the above-described valve deactivation operation.
And a structure in which a valve rest mechanism is incorporated in each of the carriers 20 and 30 is employed, so that the structure of a hydraulic pressure supply system to the valve rest mechanism can be simplified. That is, each cam carrier 20,
30 is a separate body, the oil passages 33d, 33e, 3
Drilling of 3 g is easy. By the way, in the case where the structure in which the valve rest mechanism is incorporated in the portion integrated with the cylinder head 4 is adopted, the oil passage may pass through the outer wall (cam chamber constituting wall) at the end of the cylinder head 4 in the cam axis direction. Alternatively, the structure of the hydraulic supply system becomes complicated, such as providing a branch passage in a direction perpendicular to the camshaft, and the handleability deteriorates as much as a large and heavy cylinder head requires direct drilling.

In this embodiment, the center lifter guide hole 20
a and the right side lifter guide hole 20c are arranged at different inclination angles in the direction perpendicular to the camshaft, so that the oil passages 33d and 33e are parallel to the camshaft 16 and on the outer peripheral portions of the guide holes 20a and 20c. The oil pressure can be supplied to the center intake valve deactivating mechanism 18a and the right side intake valve deactivating mechanism 18b separately and independently just by making contact so that they come into contact with each other. Incidentally, when the two guide holes 20a and 20c are arranged at the same inclination angle, each of the guide holes 20a, 20c
The structure is complicated, for example, an oil passage is provided at a position distant from c, and a branch passage is provided from the oil passage in a direction perpendicular to the camshaft.

In this embodiment, the oil passage 33c is formed so as to pass through the inside of the head side cover 6a, and the oil passage is connected to the oil passage for the valve deactivation mechanism and the oil passage for the variable valve timing mechanism in the head side cover 6a. The switching valve 3 for the valve deactivation mechanism
4, 35, and switching valve 4 for variable valve timing mechanism
5 and 46 can all be disposed on the head side cover 6a. In this case, an oil passage 33f for supplying lubricating oil to the bearings of the camshafts 16 and 17 is formed so as to pass through the cylinder head 4. As a result, for an engine that does not have a valve stop mechanism or the like, it is only necessary to change the head side cover to one having no oil passage 33c or the like, and it is easy to share parts.

In this embodiment, the switching valves 34, 3 are utilized by utilizing the dead space below the portion of the head side cover 6a that houses the variable valve timing mechanisms 41, 42.
5, 45, 46 can be provided, and an increase in the size of the engine due to the provision of the switching valve can be avoided.

FIGS. 14 and 15 are views for explaining an engine valve deactivating device according to one embodiment (second embodiment) of the present invention, in which the same reference numerals as in FIGS. 8 and 9 denote the same parts. Or a corresponding part is shown.

In the second embodiment, the valve diameter Dic of the center intake valve 11a, the valve diameters Dis1 and Dis2 of the left and right side intake valves 11b and 11c, and the valve diameters De1 and De2 of the left and right exhaust valves 13a and 13b. Means that Dis1 = Dis2> De1
= De2> Dic. That is, the center intake valve 11a has the smallest diameter.

The distance L2 of the center intake valve 11a from the cylinder axis A in the direction perpendicular to the camshaft L2 and the left and right side intake valves 11b,
The distance L2 in the direction perpendicular to the camshaft from the cylinder axis A of 11c is
L2> L1 is set.

The fuel injection valve 50 is arranged on the axis of the intake port 48, and
e, the right picture wall 48f is set to the same length. In this case, the upstream ends of the left and right picture walls 48e, 48f are located at positions away from the fuel injection valve 50, so that the fuel from the fuel injection valve 50 can be supplied not only to the center intake valve opening 9a but also to the center intake valve opening 9a. , And is supplied to the left and right side intake valve openings 9b and 9c.

The valve stop mechanism on the intake side is configured so that one or both of the left and right side intake valves 11b and 11c can be simultaneously stopped. Further, the exhaust-side valve stop mechanism is configured to be able to stop the left exhaust valve 13a. The center intake valve 1
1b, the right exhaust valve 13b is not provided with a pause mechanism, and therefore, both valves 11b, 13b are always opened and closed.

Here, the left and right side intake valves 11b, 1
In order to be able to suspend either one of 1c, a separate and independent oil passage is required. In order to make these oil passages independent, two oil passages are formed in the intake cam carrier 20 at positions away from the left and right side lifter guide holes 20b, 20c in parallel with the cam shaft 16, and each oil passage is formed. What is necessary is just to form a branch oil passage which communicates the passage with each lifter guide hole 20b, 20c.

In the device of the second embodiment, when the intake air amount is small,
As shown in FIG. 15A, the left and right side intake valves 11
b, 11c and the left exhaust valve 13a stop, and only the center intake valve 11a and the right exhaust valve 13b open and close. Therefore, the intake air flows into the cylinder only from the center-diameter center intake valve opening 9a having the smallest diameter, and the inflow speed is increased by the small inflow area. In addition, the intake air flows into the cylinder from the center intake valve opening 9a, which is present only one at the outermost position farthest from the cylinder axis A, and the direction is not disturbed by the flow in the opposite direction. As a result, the in-cylinder flow is reliably generated, and the lean air-fuel ratio combustion is stabilized.

In this case, the intake air containing fuel mixed from the fuel injection valve located at the center of the intake port 48 is supplied to the center intake valve opening 9a located so as to face the cylinder axis A.
, The air-fuel mixture directly flows toward the spark plug 25 located near the cylinder axis A, so that the air-fuel mixture is concentrated around the spark plug 25, thereby stabilizing the lean air-fuel ratio combustion. In this embodiment, since the center intake valve opening 9a is set to the smallest diameter, the ignition plug 25
Can be arranged closer to the center intake valve opening 9a side, so that the combustibility can also be improved.

At the time of the middle intake air amount, as shown in FIG. 15B, the stop operation of the right side intake valve 11c and the left exhaust valve 13a is released, and only the left side intake valve 11b is stopped. Therefore, the intake air flows from the center intake valve opening 9a and the right side intake valve opening 9c, and generates an oblique swirl in which the flow (tumble) in the cylinder axial direction and the flow (swirl) along the cylinder inner surface are combined. Thus, the lean air-fuel ratio combustion is stabilized.

At the time of a large intake amount, as shown in FIG. 15 (c), the center and left and right side intake valves 11a to 11a
Since all of 1c operates, the inflow area increases, and there is no inflow path in the intake passage, which increases the maximum intake amount.

Further, in this embodiment, since the diameter of the center intake valve 11a is the smallest, escape of the top surface of the piston 7 for avoiding interference with the valve head 11d of the center intake valve 11a can be reduced. By the way, since the center intake valve is located at the lowest position of the combustion chamber, it easily interferes with the top surface of the piston.Therefore, in the conventional engine, a large clearance is formed in a portion of the top surface of the piston facing the center intake valve. ,
There was a problem that the strength of the top of the piston was reduced due to the escape, but this embodiment can solve this problem.

FIGS. 16 and 17 show an embodiment (third embodiment) of the present invention.
FIG. 10 is a diagram for explaining an intake device for an engine according to an embodiment), wherein the same reference numerals as in FIGS. 8 and 9 indicate the same or corresponding parts.

In the third embodiment, the valve diameter Dic of the center intake valve 11a, the valve diameters Dis1 and Dis2 of the left and right side intake valves 11b and 11c, and the valve diameters De1 and De2 of the left and right exhaust valves 13a and 13b. Means that Dic = Dis2> De1 =
De2> Dis1 is set. That is, the opening 9b for the left side intake valve has the smallest diameter.

The distance L3 of the center intake valve 11a from the cylinder axis A in the direction perpendicular to the camshaft, the distance L2 of the right side intake valve 11c in the direction perpendicular to the camshaft, and the distance L1 of the left side intake valve 11b in the direction perpendicular to the camshaft L1. Is set in a relationship of L3>L2> L1. That is, the above-mentioned distance is different for all three intake valves.

The fuel injection valve 50 is disposed on an extension of the left drawing wall 48e of the intake port 48.
The left drawing wall 48e and right drawing wall 48f of 8 are set to the same length. In this case, the upstream ends of the left and right picture walls 48e and 48f are located at positions away from the fuel injection valve 50, so that the fuel from the fuel injection valve 50 mainly receives the center intake valve opening 9a and the center intake valve opening 9a. Opening 9b for left side intake valve
Is injected and supplied.

The intake-side valve stop mechanism is configured so that either one or both of the center intake valve 11a and the right-side intake valve 11c can be stopped simultaneously.
Further, the exhaust-side valve stop mechanism is configured to be able to stop the left exhaust valve 13a. Note that the center intake valve 11b and the right exhaust valve 13b are not provided with a pause mechanism, and therefore, both valves 11b and 13b are always opened and closed.

In the third embodiment, at the time of the small intake air amount,
As shown in FIG. 17A, the center intake valve 11a, the right side intake valve 11c, and the left exhaust valve 13a stop, and only the left side intake valve 11b and the right exhaust valve 13b open and close. Therefore, the intake air flows into the cylinder only from the left-side intake valve opening 9b having the smallest diameter, and the inflow speed increases by the small inflow area. Also, the intake air flows into the left side intake valve opening 9b, which is located closest to the cylinder axis A and at a position closer to the outside in the cam axis direction, and the directionality may be disturbed by the flow in the opposite direction. Absent. As a result, in-cylinder flow, particularly swirl, is reliably generated, and lean air-fuel ratio combustion is stabilized.

At the time of the middle intake amount, as shown in FIG. 17B, the stop operation of the center intake valve 11a and the left exhaust valve 13a is released, and only the right side intake valve 11b is stopped.
Therefore, the intake air flows in through the center intake valve opening 9a and the left side intake valve opening 9b, and an oblique swirl is generated in which the flow (tumble) in the axial direction of the cylinder and the flow (swirl) along the inner surface of the cylinder are combined. Thus, the lean air-fuel ratio combustion is stabilized.

At the time of a large intake amount, as shown in FIG. 17 (c), the center and left and right side intake valves 11a to 11a-1
Since all of 1c operates, the inflow area increases, and there is no inflow path in the intake passage, which increases the maximum intake amount.

FIG. 18 shows an embodiment (fourth embodiment) of the present invention.
In the figure, the same reference numerals as in FIG. 9 indicate the same or corresponding parts. In the fourth embodiment, each intake valve,
The relationship between the diameter of the exhaust valve, the position of the fuel injection valve 50, the left,
The shapes of the right image walls 48e and 48f are set similarly to those shown in FIG. On the other hand, the valve stop mechanism on the intake side can stop only the center intake valve 11a, and the valve stop mechanism on the exhaust side can stop only the right exhaust valve 13b.

In the fourth embodiment, at the time of a small intake amount, FIG.
As shown in FIG. 8A, the center intake valve 11a and the right exhaust valve 13b are stopped, and intake air is supplied to the left and right side intake valve openings 9a.
b, 9c, and the exhaust gas flows out of the left exhaust valve 13a. As described above, the intake air flows into the cylinder from the left and right side intake valve openings 9b and 9c located on the left and right sides near the cylinder axis, so that tumble is easily generated.

At the time of the middle intake air amount, as shown in FIG. 18B, the center intake valve 11a continues to be stopped, and the stop of the right exhaust valve 13b is released. Therefore, a relatively large amount of intake air flows in from the left and right side intake valve openings 9b and 9c as in the case of the small intake amount, so that the tumble is more reliable. Further, in this case, since both of the exhaust valves operate, the exhaust gas is reliably discharged.

Further, when the intake air amount is high, all the intake valves are operated, so that a sufficient maximum intake air amount can be secured.

Here, in the first to fourth embodiments, the valve is stopped in a state where the oil pressure is not supplied, and the valve stop is released when the oil pressure is supplied. On the contrary, when the oil pressure is supplied, the valve is stopped. The valve may be stopped, and the valve stop may be released if no oil pressure is supplied. With this configuration, it is possible to provide a valve stop mechanism for all valves, and the degree of freedom in design is increased.

In other words, if the valve stop is released without oil pressure, all valves are operated regardless of the presence or absence of the valve stop mechanism until the oil pressure is generated at the time of starting the engine. Even if the valve is provided with a valve stop mechanism, the valve can be started. By the way, as in the case of the above embodiment, if the valve stop is released with hydraulic pressure, if all the valves are provided with the valve stop mechanism, the engine cannot be started, and eventually at least one intake valve The exhaust valve must be provided with no valve rest mechanism. In the above embodiment, at least one of the intake valve and the exhaust valve is not provided with a valve rest mechanism.

FIG. 19 shows an embodiment (fifth embodiment) of the present invention.
In the figure, the same reference numerals as in FIG. 9 indicate the same or corresponding parts. The present embodiment is an example in which the valve stop is released without hydraulic pressure, and a stop enabling mechanism is provided for all the intake valves 11a to 11c.

In the fifth embodiment, the relationship between the diameters of the intake valves and the exhaust valves, the position of the fuel injection valve 50, the left and right image walls 48 are provided.
The shapes of e and 48f are set similarly to those shown in FIG. On the other hand, the valve stop mechanism on the intake side can switch and stop one of the center intake valve 11a and one of the left and right side intake valves 11b and 11c. Further, the exhaust-side valve stop mechanism can stop only the right exhaust valve 13b.

In the fifth embodiment, since no oil pressure is generated at the time of starting, all the valve stop mechanisms are released, so that all the valves perform opening and closing operations and can be started without any trouble. At the time of the small intake amount, as shown in FIG. 19A, the left and right side intake valves 11b and 11c and the right exhaust valve 13b are stopped, and the stop of the center intake valve 11a is released. Therefore, the intake air flows in from the center intake valve opening 9a, and the exhaust gas flows out from the left exhaust valve 13a. As described above, the intake air flows from the center intake valve opening 9a, which is the smallest in diameter and is located at a position distant from the cylinder axis A, so that the inflow speed is high, the directionality is clear, and the in-cylinder flow is reduced. It occurs reliably and the lean air-fuel ratio combustion is stabilized.

Further, in this case, the air-fuel mixture is concentrated on the spark plug 25, whereby the lean air-fuel ratio combustion is stabilized. In addition, since the center intake valve opening 9a is set to the smallest diameter, the ignition plug 25 can be arranged closer to the center intake valve opening 9a side, and from this point also, the combustibility can be improved.

At the time of the middle intake amount, as shown in FIG. 19B, the center intake valve 11a is stopped, and the stop of the left and right side intake valves 11b, 11c and the right exhaust valve 13b is released. For this switching, first, the left and right side intake valves 11a are operated with the center intake valve 11a operated.
b, 11c are released, and then the center intake valve 11 is released.
It is desirable to pause a. Thereby, the shock at the time of switching is reduced.

By releasing the deactivation of the left and right side intake valves 11b and 11c, a relatively large amount of intake air flows in from the left and right side intake valve openings 9b and 9c in the same manner as in the case of the small intake amount. Is more certain. Also in this case,
Since both of the exhaust valves operate, the exhaust gas is reliably discharged.

Further, at the time of a high intake air amount, all the intake valves are operated, so that a sufficient maximum intake air amount can be secured.

FIG. 20 shows a modification of the valve stop control in the first embodiment. In the present modification, the same pause control as in the first embodiment is performed at the time of a small intake air amount (see FIG. 7A), but the control at the time of the medium intake air amount and the control of the large intake air amount are different. That is, at the time of the middle intake amount, as shown in FIG.
3a is stopped, and the large intake air amount operation region is divided into an operation region with a relatively small intake air amount and an operation region with a large intake air amount. In the operation region with a relatively small intake air amount, as shown in FIG. The center intake valve 11a releases the pause, and the left exhaust valve 13a continues the pause as in the case of the medium intake amount. Then, all the valves are operated in the operation range where the intake air amount is large.

With this configuration, only one exhaust valve is operated in the first half of the above-described large-intake-amount operating range, so that the equivalent pipe length of the exhaust pipe in the large-intake-amount operating range becomes longer. As shown by the two-dot chain line torque curve C 'in FIG. 22, the torque in the high-speed rotation region (large intake air amount operation region) can be further improved.

FIG. 21 shows a modification of the valve stop control in the second embodiment. In the present modification, the same pause control as in the second embodiment is performed at the time of a small intake air amount (see FIG. 7A) and at the time of a large intake air amount (see FIG. 7C). Different control. That is, the middle intake air amount operation region is divided into an operation region where the intake air amount is relatively small and an operation region where the intake air amount is relatively large, and in the operation region where the intake air amount is small, as shown in FIG.
a, only the right side intake valve 11c and the right exhaust valve 13b are operated, and the left exhaust valve 13a continues to be inactive. Then, in the operation range where the intake air amount is relatively large, the left exhaust valve 13a is also operated as in the second embodiment.

With this configuration, only one exhaust valve is operated in the first half of the above-mentioned middle intake air amount operation range, so that the equivalent pipe length in the middle intake air amount operation region of the exhaust pipe becomes longer. As shown by the two-dot chain line torque curve B 'in FIG. 22, the torque in the medium speed rotation region (medium intake air amount operation region) can be further improved.

In each of the embodiments described above, the case of a five-valve engine having three intake valves and two exhaust valves has been described. However, in the present invention, two or four or more intake valves are arranged closer to the cylinder shaft side. The present invention can also be applied to a case where it is separately arranged near the side opposite to the cylinder axis.

In each of the above embodiments, the valve lift curves of the intake valve and the exhaust valve may be set as follows according to the valve diameter, and the above-described valve stop control may be performed.

For example, the maximum lift of the small diameter valve is set smaller than the maximum lift of the large diameter valve. As a result, the following effects can be obtained in addition to the effects obtained by employing the small-diameter valve and performing the valve stop control. That is, the lifter diameter for the small-diameter valve can be reduced by an amount corresponding to the reduction in the maximum lift amount of the small-diameter valve, so that the lifter diameter for the large-diameter valve can be increased in space, and the maximum lift of the large-diameter valve can be increased. Thereby, the ratio (dynamic range) between the flow rate when the large diameter valve is stopped and the flow rate when the small diameter valve is stopped can be increased. As a result, the in-cylinder flow at the time of the small intake amount can be further enhanced, and the maximum intake amount at the time of the large intake amount can be further increased. In addition, it is possible to avoid a waste in which the lift amount is excessive despite the small diameter valve. That is, in the case of a small-diameter valve, there is no effect in increasing the flow rate even if the lift is larger than necessary.

By using the above-described variable valve timing mechanism or by appropriately setting the cam nose shape, the opening / closing timing of the valve that opens and closes in the low-speed rotation range of the engine can be controlled by the overlap between the exhaust valve and the intake valve. Try to be smaller. This can be realized by advancing the closing timing of the exhaust valve and retarding the opening timing of the intake valve. By reducing the overlap in the low-speed rotation range in this manner, combustion in the low-speed rotation range can be improved, idle rotation can be stabilized, and low-speed torque can be increased.

Further, in each of the above embodiments, various effects can be obtained by changing the valve diameter. However, the same effect can be obtained by changing the lift amount and the seat angle α in FIG. 23 without changing the valve diameter. The effect of can be obtained. For example, as shown in FIG. 23, in each of the above embodiments, the valve diameters are all the same, and the valve (intake valve) disposed at the portion having the small diameter is set to a small lift, and the seat angle α is reduced. The valve (intake valve) arranged at the portion having the diameter is set to a large lift and the seat angle α is increased. By combining this with the valve rest control of the above embodiment, the same effect as in the above embodiment can be obtained for the following reasons.

Here, the present inventors have confirmed through experiments and the like that when the lift amount is H, the effective opening area and, consequently, the flow rate are proportional to Hcos α. That is, as shown in FIG. 24, when α is small (see curve A), the flow rate increases rapidly at the initial stage of opening of the valve (see FIG. 23, the flow rate does not further increase due to the large bending resistance (FIG. 23).
(C)). On the other hand, when α is large (see curve B), the increase in the flow rate is relatively slow at the beginning of opening of the valve (see FIG. 23 (e)) because the opening area is slowly increased. The flow rate greatly increases by a small amount (see FIG. 23 (f)).

As described above, using a small α and a small lift is equivalent to a small-diameter valve, and using a large α and a large lift is equivalent to a large-diameter valve, and can be replaced as described above. Moreover, in this case, since the valve diameters are all the same, it is possible to cope only by changing the seat angle α, and manufacturing is easy. In addition, the valve having the small seat angle α uses the small lift portion, and the valve having the large seat angle α uses the large lift portion. It is efficient.

[0109]

According to the first aspect of the present invention, the first and second oil passages are formed in common from the oil pump to the side cover inlet, and are formed within the side cover.
Since the first and second switching valves are disposed downstream of the branch, the oil passage structure can be simplified. In addition, at least a part of the first oil passage to the valve deactivating mechanism and a first switching valve for opening and closing the first oil passage are provided on a side cover disposed on an end face of the cylinder head, and a first switch to the variable valve timing mechanism is provided. And at least a portion of the second oil passage and a second oil passage opening and closing the second oil passage.
Since the switching valve is provided on the side cover, only the side cover has a different structure, so that an engine having a valve stop mechanism and a variable valve timing mechanism and an engine not having the valve stop mechanism have components such as a cylinder block, a cylinder head, and a head cover. There is an effect that sharing can be achieved.

The outer end of the variable valve timing mechanism is supported by a side cover, and the second oil passage can communicate from the outer end support of the side cover to an oil passage formed in the outer end. Therefore, there is an effect that the structure of the oil passage to the variable valve timing mechanism can be simplified.

Furthermore, since the first oil passage to the valve rest mechanism extends parallel to the camshaft and is in contact with the lifter guide hole, the structure of the first oil passage to the valve rest mechanism can be simplified. There is.

According to the second aspect of the present invention, the third camshaft lubrication required regardless of whether or not a valve rest mechanism is provided.
Since the oil passage is formed so as to pass through the inside of the cylinder head, the cylinder head can have the same structure with or without the valve rest mechanism and the variable valve timing mechanism. There is an effect that can be achieved.

[Brief description of the drawings]

FIG. 1 is a front view of a four-stroke engine including a valve stop mechanism and a variable valve timing mechanism according to a first embodiment of the present invention.

FIG. 2 is a sectional front view showing a right side intake valve and a right exhaust valve portion of the engine of the first embodiment.

FIG. 3 is a sectional front view showing a center intake valve portion of the engine of the first embodiment.

FIG. 4 is a sectional front view showing a left side intake valve and a left exhaust valve portion of the engine of the first embodiment.

FIG. 5 is a plan view showing a state in which intake and exhaust cam carriers of a cylinder head of the engine of the first embodiment are removed.

FIG. 6 is a partial cross-sectional plan view of intake and exhaust cam carriers of the engine of the first embodiment.

FIG. 7 is a sectional rear view showing the oil system of the engine of the first embodiment.

FIG. 8 is a schematic sectional plan view showing an intake valve opening and an exhaust valve opening of the engine of the first embodiment.

FIG. 9 is a schematic diagram for explaining the operation of the engine of the first embodiment.

FIG. 10 is a sectional view showing a valve deactivating mechanism of the engine of the first embodiment.

FIG. 11 is a sectional view showing a valve deactivating mechanism of the engine of the first embodiment.

FIG. 12 is a sectional view showing a valve deactivating mechanism of the engine of the first embodiment.

FIG. 13 is an oil system diagram of the engine of the first embodiment.

FIG. 14 is a schematic sectional plan view showing an intake valve opening and an exhaust valve opening of a four-cycle engine according to a second embodiment of the present invention.

FIG. 15 is a schematic diagram for explaining the operation of the engine of the second embodiment.

FIG. 16 is a schematic sectional plan view showing an intake valve opening and an exhaust valve opening of a four-cycle engine according to a third embodiment of the present invention.

FIG. 17 is a schematic diagram for explaining the operation of the engine of the third embodiment.

FIG. 18 is a schematic diagram for explaining an operation of a four-cycle engine according to a fourth embodiment of the present invention.

FIG. 19 is a schematic diagram for explaining an operation of the four-cycle engine according to the fifth embodiment of the present invention.

FIG. 20 is a schematic diagram for explaining a modified example of the valve stop control operation of the engine of the first embodiment.

FIG. 21 is a schematic diagram for explaining a modification of the valve stop control operation of the engine of the second embodiment.

FIG. 22 is an engine speed-torque characteristic diagram for explaining the effect of the engine of the first embodiment.

FIG. 23 is a schematic diagram showing a development example of each of the above embodiments.

FIG. 24 is an engine speed-flow rate characteristic diagram showing the effect of the above-mentioned development.

[Explanation of symbols]

 Reference Signs List 1 4 cycle engine 3 oil pan 4 cylinder head 6a head side cover 6c outer end support portion 11a to 11c intake valve 13a, 13b exhaust valve 16, 17 intake, exhaust camshaft 18a, 18b, 19 valve stop mechanism 20d, 20e cam Shaft bearing 32 Oil pump 33a Common oil passage 33f Third oil passage 34,35 First switching valve 41,42 Variable valve timing mechanism 43a Support shaft (outer end) 43e Oil introduction passage 45,46 Second switching valve a, b 1st oil passage (branch passage) c 2nd oil passage (branch passage)

────────────────────────────────────────────────── ─── front page continued (51) Int.Cl. ⁷ identifications FI F02D 13/02 F02D 13/02 E (56 ) references Patent Rights 4-262021 (JP, a) JP Akira 62-107218 ( JP, A) JP-A-4-209908 (JP, A) JP-A-4-19610 (JP, U) WO 93/24737 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB Name) F01L 13/00

Claims (2)

(57) [Claims] 1. A valve rest mechanism for holding a valve in a closed position is disposed between a camshaft and a valve shaft .
Variable valve timing mechanism that changes opening and closing timing
In four-stroke engines equipped with, the camshaft
Removably mounted on the end face of the cylinder head to cover the end
The above variable valve timing machine is installed inside the installed side cover.
And the outside of the variable valve timing mechanism.
The end is supported by the outer end support of the side cover
The above-mentioned valve rest mechanism is connected to the lifter guide of the cam carrier.
Slidably disposed in the through hole to transmit the operation of the camshaft to the valve shaft
And a hydraulically driven type installed in the valve lifter
And an oil pump installed near the oil pan.
The above-mentioned valve pause mechanism, variable valve timing mechanism
First and second oil passages for supplying oil to the oil pump
To the side cover entrance and the side cover
Branched into a first oil passage and a second oil passage in the cover.
And a second structure for opening and closing the first and second oil passages.
1. Place the second switching valve on the downstream side of the branch section, and
The first cover.
The downstream side of the first switching valve of the oil passage is connected to the side cover
From the inside parallel to the camshaft and contact the lifter guide hole.
Formed on the cam carrier so that the second oil
The downstream side of the second switching valve of the passage is connected to the outside of the side cover.
Outer end of the variable valve timing mechanism from the end support
Formed so as to communicate with the oil introduction passage formed therein.
A four-stroke engine characterized by: 2. The four-stroke engine according to claim 1, wherein a third oil passage for supplying oil from the oil pump to a camshaft bearing is formed so as to pass through the cylinder head. .