JPH0573208U - Valve drive for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] A hydraulic control device is efficiently arranged to reduce the size of an internal combustion engine. A valve train of a V-type multi-cylinder internal combustion engine in which two rows of cylinders 3 are arranged at a predetermined angle with respect to a crankshaft 2, and two rows of low speed cams 14 and high speed cams 15 are mounted. Corresponding to each cylinder 3 of the camshaft 1 arranged axially offset from each other
2 and 13 and a pair of rocker shafts 21 and 22. The rocker shafts 21 and 22 are integrally mounted with a main rocker arm 33 whose swing end faces the upper end of the intake or exhaust valves 79 and 80. Lockers 52 and 59 for engaging and disengaging the rocker arms 34 and 35 for low speed and the rocker arms 35 for high speed with which the cams 14 for high speed and the cams 15 for high speed are engaged, respectively, and their operation A hydraulic control device 86 for controlling the above is provided, and the hydraulic control means 86 is disposed in a space formed by offsetting the camshafts 12 and 13.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a valve operating system for an internal combustion engine that controls the operation of an intake valve and an exhaust valve provided in an automobile engine or the like.

[0002]

[Prior Art]

 Generally, the opening / closing control of the intake valve and the exhaust valve in an automobile engine is set according to the operating state obtained from the engine speed and the accelerator pedal depression amount. In addition, in such a valve operating system, it has been proposed to change the cam profile in order to reduce fuel consumption at low speeds and to perform efficient intake and exhaust at high speeds according to operating conditions. .. This is done by changing the opening / closing timing of the intake and exhaust valves, the lift amount, the opening period, etc. at low speed or high speed.

That is, in an automobile engine, a high speed cam and a low speed cam are provided on a cam shaft, and the high speed cam has a cam profile capable of obtaining a valve opening / closing timing corresponding to a high speed operation. The cam has a cam profile that can obtain the valve opening / closing timing corresponding to low speed operation. Then, by selectively using the high-speed cam or the low-speed cam according to the operating state while the engine is operating, it is possible to obtain the optimum opening / closing timing of the intake valve and the exhaust valve. Is becoming

Further, in such an automobile engine, a cylinder deactivation mechanism has been conventionally used to reduce fuel consumption during idle operation or low load operation, for example, in the case of a four-cylinder engine, two cylinders of the four-cylinder engine are stopped. More suggested. That is, in the valve train, the piston is operating during idle operation or low load operation, but the operation of the intake valve and exhaust valve is stopped so that fuel is not supplied.

The cylinder deactivation mechanism for stopping the operation of the intake valve and the exhaust valve is generally operated by providing a rocker arm with a switching mechanism and hydraulically controlling the switching mechanism. In this case, hydraulic pressure is supplied from the main oil pump of the engine to the switching mechanism via the oil passage. However, in order to operate the switching mechanism, high hydraulic pressure cannot be obtained from the main oil pump of the engine alone, which is insufficient. That is, as shown in FIG. 13, there is a minimum required switching oil pressure for operating the switching mechanism, and the operating oil pressure from the main oil pump of the engine becomes less than this required switching oil pressure. Therefore, by providing an assist oil pump in addition to the main oil pump of the engine, the operating oil pressure of the switching mechanism is made higher than the operation required oil pressure.

FIG. 14 is a plan view of a cylinder head showing a valve operating system of an engine having a conventional cylinder deactivating mechanism, and FIG. 15 shows a hydraulic path of the valve operating system.

As shown in FIGS. 14 and 15, a cam shaft 202 is rotatably attached to the center of the cylinder head 201, and a cam (not shown) is integrally formed at a predetermined position. A pair of rocker shafts 203 are also rotatably attached to the cylinder head 201 in parallel with the cam shaft 202. A rocker arm 204 and a base end of a rocker arm 206 having a switching mechanism 205 are mounted on each rocker shaft 203, and rocking ends of the rocker arms 204 and 206 face an upper end of an intake or exhaust valve 207. is doing. An oil pump 208, an accumulator 209, and an oil control valve 210 are attached to the end of the cylinder head 201. The oil pump 208 can be driven by a drive cam 211 attached to one end of the cam shaft 202, and the oil control valve 210 can be operated by a control signal from the control unit 212.

When the camshaft 202 rotates, the cam rocks the rocker arm 204 and the rocker arm 206 to drive the intake and exhaust valves 207. Then, during idle operation of the engine or during low load operation, two cylinders out of the four cylinders are stopped to operate. That is, the oil pump 208 is driven by the drive cam 211 of the camshaft 202, and the hydraulic pressure is stored in the accumulator 209. On the other hand, the control unit 212 discriminates the operating state of the engine from the signals from various sensors, sends a control signal to the oil control valve 210, and switches it. Then, the hydraulic pressure is sent to the switching mechanism 205 of the rocker arm 206, and the driving of the corresponding intake and exhaust valves 207 is stopped. Therefore, the engine operates only by driving the intake and exhaust valves 207 corresponding to the rocker arm 204.

[0009]

[Problems to be solved by the device]

 In the above-described conventional engine valve operating system, a switching mechanism 205 is attached to some rocker arms 206 in order to stop two cylinders out of four cylinders during idle operation or low load operation. Therefore, the oil pump 208 or the accumulator 209 is required, and these must be mounted on the cylinder head 201. Conventionally, as described above, the cylinder head 201 is provided above one end, but this causes a part of the engine to project upward. Further, the cylinder head cover that covers the upper part of the cylinder head 201 must also be shaped so as to partly project upwards accordingly, and the height of the engine becomes high. This not only led to an increase in size, but also made the layout when mounted on the vehicle difficult.

The present invention solves such a problem, and an object of the present invention is to provide a valve train for an internal combustion engine, which is designed to be compact.

[0011]

[Means for Solving the Problems]

 In order to achieve the above object, a valve operating system for an internal combustion engine of the present invention is a multi-cylinder internal combustion engine in which two rows of cylinders are arranged at a predetermined angle with respect to a crankshaft. A pair of cam shafts, each of which is provided with a corresponding cam and is axially offset from each other in correspondence with each of the two rows of cylinders, and a pair of rocker shafts, each of which is arranged parallel to each of the cam shafts. The base end is integrally attached to the rocker shaft described above, the swing end faces the upper end of the intake or exhaust valve, and either the low-speed cam or the high-speed cam engages with the main rocker arm. A sub-rocker arm rotatably attached to a rocker shaft and engaged with the other of the low-speed cam and the high-speed cam, and a radial direction inside the rocker shaft. The hydraulic pressure is set to a lock pin that is movably provided in each of the through holes and that engages and disengages with the sub rocker arm, and a hydraulic pressure to a hydraulic passage that is provided in the axial center portion of the rocker shaft along the axial direction. And a hydraulic pressure control device for controlling the operation of the lock pin, and the hydraulic control device is arranged in a space formed by offsetting each of the camshafts. ..

[0012]

[Action]

 In a multi-cylinder internal combustion engine in which two rows of cylinders are arranged at a predetermined angle with respect to the crankshaft, by disposing the hydraulic control device in the space formed by offsetting each camshaft, This saves space and makes the device compact, which makes layout on the vehicle easier.

[0013]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view of a cylinder head representing a valve operating system for an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a sectional view taken along the line BB of FIG. 4 is a sectional view taken along the line CC of FIG. 1, FIG. 5 is a plan view of the valve operating device with the cylinder deactivating mechanism, FIG. 6 is a cross section taken along the line D-D of FIG. 5, FIG. 7 is a cross section taken along the line EE of FIG. Fig. 9 is an exploded perspective view of the valve operating device, Fig. 9 is a cross section showing the switching mechanism of the valve operating device, Fig. 10 is a hydraulic path of the valve operating device, Fig. 11 is a description of the operation of the switching mechanism, and Fig. 12 is a cylinder without a cylinder deactivating mechanism. The cross section of a valve train is shown.

In the internal combustion engine of this embodiment, two rows of cylinders are arranged in a V shape at a predetermined angle with respect to the crankshaft, and each cylinder has two camshafts. A DOHC) V-type 6-cylinder engine having two valves for intake and two valves for exhaust.

As shown in FIGS. 1 and 2, a crankshaft 2 is rotatably supported by a cylinder block 1, and three cylinders in two rows each having a predetermined angle with respect to the crankshaft 2. 3 is formed in a V shape. In this case, the two rows of cylinders 3 are formed so as to be displaced in the axial direction of the crankshaft 2. A piston 5 is connected to the crankshaft 2 via a connecting rod 4, and the piston 5 is movably fitted in each cylinder 3. Further, valve operating mechanisms 6 and 7 are provided above the cylinders 3 corresponding to the two rows of cylinders 3, respectively. Since the valve operating mechanisms 6 and 7 have almost the same structure, only one of them will be described below. And, as described above, the cylinders 3 are inclined with respect to the crankshaft 2 at a predetermined angle, but in order to make the explanation easy to understand, they are shown in an upright state in the drawings.

As shown in FIGS. 2 and 5 to 7, the cylinder head 11 includes a pair of intake camshafts 12 and exhaust cams that are located above the cylinder 3 and are parallel to each other along the longitudinal direction thereof. A shaft 13 is provided, and a low speed cam 14 having a small lift amount and a high speed cam 15 having a large lift amount are integrally formed for each cylinder. The pair of camshafts 12 and 13 are held by the upper portion of the camshaft housing 16 and the plurality of cam caps 17 and fixed to the upper portion of the cylinder head 11 by the bolts 18 and 19. It is rotatably supported.

Further, a pair of intake rocker shaft 21 and exhaust rocker shaft 22 that are parallel to each other along the longitudinal direction of the cylinder head 11 and that are parallel to the pair of cam shafts 12 and 13 are provided. It is arranged for each cylinder. The pair of rocker shafts 21 and 22 is clamped by the lower portion of the camshaft housing 16 and the plurality of rocker shaft caps 23 and fixed to the lower portion of the cylinder head 11 by the bolts 19 and 24. 1 is rotatably supported. A cylinder head cover 25 is fixed to the upper part of the cylinder head 11.

Each rocker shaft 21, 22 has a valve operating device that can be switched between a valve opening / closing timing for high speed operation and a valve opening / closing timing for low speed operation, a valve opening / closing timing for high speed operation, and a valve opening / closing timing for low speed operation. It is equipped with a valve train that can be deactivated during low-load operation as well as being switched to. That is, as shown in FIG. 1, the valve operating devices 31 of the upper two cylinders out of the six cylinders have a cylinder deactivating mechanism, and the valve operating devices 32 of the lower four cylinders do not have a cylinder deactivating mechanism.

Here, the valve operating device 31 with the cylinder deactivation mechanism will be described. As shown in FIG. 8, a main rocker arm 33 having a T-shape in plan view and a low speed rocker arm 34 and a high speed rocker arm 35 as sub rocker arms are mounted on the exhaust rocker shaft 22 on both sides thereof. .. The base end of the main rocker arm 33 is integrally fixed to the rocker shaft 22 by, for example, spline connection, and an adjusting screw 36 is attached to the swinging end of the main rocker arm 33 by an adjusting nut 37. Is in contact with the upper end of the exhaust valve 80 described later.

On the other hand, the low-speed rocker arm 34 is rotatably supported by its base end pivotally attached to the rocker shaft 22, and a roller bearing 38 is attached to its swing end. The low speed cam 14 can be engaged. Similarly, the high speed rocker arm 35 has its base end rotatably supported by being pivotally attached to the rocker shaft 22, and has a roller bearing 39 attached to its swing end. The cam 15 can be engaged.

Further, as shown in FIG. 7, the low-speed rocker arm 34 and the high-speed rocker arm 35 are respectively provided with arm portions 40, 40 on the opposite side to the rocking ends to which the roller bearings 38, 39 are attached. 41 is integrally formed, and lost motions 42 and 43 act on the arm portions 40 and 41. The lost motions 42 and 43 are composed of a cylinder 44 fixed to the cam cap 17, a plunger 45, and a compression spring 46. The tip end of the plunger 45 presses the arm portions 40 and 41, and is shown on the left side in FIG. The rocker arms 34 and 35 are urged clockwise, and the rocker arms 34 and 35 shown on the right side are urged counterclockwise, respectively.

Therefore, normally, in the low speed rocker arm 34 and the high speed rocker arm 35, the roller bearings 38 and 39 contact the outer peripheral surfaces of the low speed cam 14 and the high speed cam 15 of the cam shaft 13 by the lost motions 42 and 43. When the cam shaft 13 rotates, the cams 14 and 15 act to rock the low speed rocker arm 34 and the high speed rocker arm 35.

As shown in FIG. 9, the low speed rocker arm 34 and the high speed rocker arm 35 can rotate integrally with the rocker shaft 22 by the switching mechanism 50. A through hole 51 is formed in the rocker shaft 22 at a position corresponding to the low speed rocker arm 34 along its radial direction. A lock pin 52 is movably mounted in the through hole 51 and a spring seat 53 is provided. It is biased in one direction by a compression spring 54 supported by. On the other hand, the low speed rocker arm 34 has an engagement hole 55 formed at a position corresponding to the through hole 51 of the rocker shaft 22, and the lock pin 52 urged by the compression spring 54 is engaged with the engagement hole 55. ing. The rocker shaft 22 is formed with a hydraulic passage 56 communicating with the through hole 51 along the axial direction thereof, and the lock pin 52 has a side communicating with the hydraulic passage 56 and engaging with the engaging hole 55. An oil passage 57 that opens at is formed.

A through hole 58 is formed in the rocker shaft 22 at a position corresponding to the high speed rocker arm 35 along the radial direction thereof, and a lock pin 59 is movably mounted in the through hole 58. A compression spring 60 biases the compression spring 60 in one direction. On the other hand, an engaging hole 61 is formed in the high speed rocker arm 35 at a position corresponding to the through hole 58 of the rocker shaft 22, and the lock pin 59 is pulled out from the engaging hole 59 by a compression spring 60. A hydraulic passage 62 communicating with the through hole 58 is formed in the rocker shaft 22 along its axial direction, and an oil passage 63 communicating with the end of the through hole 58 opposite to the engaging hole 59 is formed. Has been done.

In general, as shown in FIG. 11A, in the low speed rocker arm 34, the lock pin 52 urged by the compression spring 54 is engaged with the engagement hole 55 to cause the rocker shaft 22 to move. It is possible to rotate together with the main rocker arm 33 via the rocker shaft 22. On the other hand, in the high speed rocker arm 35, the lock pin 59 urged by the compression spring 60 comes out of the engaging hole 61, the engagement with the rocker shaft 22 is released, and the rocker shaft 22 is prevented from rotating integrally with the rocker shaft 22. It has become. Therefore, the low speed cam 14 and the high speed cam 15 swing the low speed rocker arm 34 and the high speed rocker arm 35, but only the driving force transmitted by the low speed rocker arm 34 is transmitted via the rocker shaft 22. The main rocker arm 33 is transmitted to the arm 33 and can swing.

Then, when hydraulic pressure is supplied to the hydraulic passages 56 and 62 of the rocker shaft 22, as shown in FIG. 11B, in the low speed rocker arm 34, the pressure oil passes through the oil passage 57. The lock pin 52 flows toward the engagement hole 55 side of the through hole 51, and is pulled out from the engagement hole 55 against the biasing force of the compression spring 54. Then, the low speed rocker arm 34 and the rocker shaft 22 are disengaged from each other so that they do not rotate together. On the other hand, in the high-speed rocker arm 35, the pressure oil flows through the oil passage 63 to the opposite side of the through hole 58 from the engaging hole 61, and the lock pin 59 resists the urging force of the compression spring 54. The engagement hole 61 is engaged. Then, the high-speed rocker arm 35 and the rocker shaft 22 are engaged with each other, and both can rotate integrally. Therefore, the low speed cam 14 and the high speed cam 15 swing the low speed rocker arm 34 and the high speed rocker arm 35, but only the driving force transmitted from the high speed rocker arm 35 is transmitted via the rocker shaft 22 to the main rocker. The main rocker arm 33 is transmitted to the arm 33 and can swing.

When hydraulic pressure is supplied only to the hydraulic passage 56 of the rocker shaft 22, as shown in FIG. 11C, in the low-speed rocker arm 34, the pressure oil causes the engaging hole 55 of the through hole 51 to pass. The lock pin 52 flows out to the side, and the lock pin 52 is pulled out from the engagement hole 55, and the low speed rocker arm 34 and the rocker shaft 22 are disengaged from each other so that they do not rotate integrally. On the other hand, in the high-speed rocker arm 35, the lock spring 59 is pulled out from the engagement hole 61 by the compression spring 60 and the engagement with the rocker shaft 22 is released, so that both do not rotate together. Therefore, the low speed cam 14 and the high speed cam 15 swing the low speed rocker arm 34 and the high speed rocker arm 35, but the driving force is not transmitted to the rocker shaft 22 and the main rocker arm 33 does not operate. It is possible to set the cylinder in a resting state without doing so.

Further, in the valve operating device 32 without the cylinder deactivating mechanism, as shown in FIG. 12, a low-speed rocker arm 64 and a high-speed rocker arm 65 each having a T-shape in plan view are provided on the exhaust rocker shaft 22. It is installed. The low speed rocker arm 64 has its base end integrally fixed to the rocker shaft 22. A roller bearing 66 is attached to the rocking end of the low speed rocker arm 64 so that the low speed cam 14 can be engaged, and an adjusting screw 67 is attached by an adjusting nut 68. The lower end of 67 is in contact with the upper end of an exhaust valve 80 described later.

On the other hand, the rocker arm 65 for high speed is rotatably supported by the base end of which is pivotally attached to the rocker shaft 22, and the roller bearing 69 is attached to the rocking end thereof. The high speed cam 15 can be engaged. Further, the high-speed rocker arm 65 is integrally formed with an arm portion 70 on the side opposite to the swing end to which the roller bearing 69 is attached. The lost motion 71 acts on the arm portion 70, and the high-speed rocker arm 65 is operated. The arm 65 is biased in one direction. Further, the high speed rocker arm 65 can rotate integrally with the rocker shaft 22 by the switching mechanism 72. That is, a through hole 73 is formed in the rocker shaft 22 at a position corresponding to the high speed rocker arm 65, and a lock pin 74 is movably mounted and is biased and supported by a compression spring 75. On the other hand, an engaging hole 76 is formed in the high speed rocker arm 65, and the lock pin 74 is pulled out from the engaging hole 76 by the compression spring 75. A hydraulic passage 77 communicating with the through hole 73 is formed along the axial direction of the rocker shaft 22, and an oil passage 78 communicating with the end of the through hole 73 opposite to the engaging hole 76. Are formed.

In the high-speed rocker arm 65, the lock pin 74 is normally pulled out from the engagement hole 76 by the compression spring 75, and the locker shaft 22 is disengaged from the rocker shaft 22 to be integrated with the rocker shaft 22. It doesn't rotate. Therefore, the low speed cam 14 and the high speed cam 15 swing the low speed rocker arm 64 and the high speed rocker arm 65. However, the driving force of the low speed cam 14 is transmitted to the exhaust valve 80 described later, and the exhaust gas is exhausted. The valve 80 can be rocked. When hydraulic pressure is supplied to the hydraulic passage 77 of the rocker shaft 22, in the high-speed rocker arm 65, the pressure oil flows through the oil passage 78 to the opposite side of the engaging hole 76 of the through hole 73 and locks. The pin 59 is engaged with the engagement hole 76. Then, the high-speed rocker arm 65 and the rocker shaft 22 engage with each other, and the rocker shaft 22 and the rocker shaft 22 can rotate together. Therefore, the high-speed cam 15 swings the high-speed rocker arm 35, and the driving force is transmitted to the exhaust valve 80 via the rocker shaft 22 and the low-speed rocker arm 64 to swing the exhaust valve 80. You can do it.

In the above description of the valve operating devices 31 and 32, only the exhaust side has been described. However, the intake side has a similar structure, and each valve is opened and closed in accordance with the intake / exhaust valve opening / closing timing. Only the formation positions of the cam shafts 12 and 13 in the circumferential direction of the cams 14 and 15 are different.

By the way, as shown in FIG. 7, the intake valve 79 and the exhaust valve 80 are movably mounted on the cylinder head 11, and the valve springs 81 and 82 close the intake port 83 and the exhaust port 84. Therefore, by driving the main rocker arm 33 (low speed rocker arm 64) described above to press the upper ends of the intake valve 79 and the exhaust valve 80, the intake port 83 and the exhaust port 84 are opened and closed to open the combustion chamber. It is possible to communicate with 85.

As shown in FIGS. 1, 3 and 4, in the cylinder head 11, the camshafts 12 and 13 are also axially offset corresponding to the rows of the left and right offset cylinders 3, respectively. As a result, a space is formed at the axial end of each camshaft 12, 13. Therefore, in this embodiment, the hydraulic control device 86 for operating the switching mechanisms 50, 72 of the valve operating devices 31, 32 is provided in this space. The hydraulic control device 86 includes an oil pump 87, an accumulator 88, a high speed switching oil control valve 89, and a cylinder switching oil control valve 90. The hydraulic control devices 86 provided at the axial end portions of the left and right camshafts 12, 13 have substantially the same structure, and only one of them will be described.

The oil pump 87 and the accumulator 88 are located between the intake camshaft 12 and the exhaust camshaft 13, and both are arranged side by side, and the axial center directions of both are horizontal. ing. That is, the cylinder 91 of the oil pump 87 is horizontally movable on the upper side of the cam cap housing 16 and the cam cap 17 at the rearmost part of the cylinder head 11 and is biased by the compression spring 92. , And is fixed by a bolt 94 via a cover 93. A plunger 96 acts on the cylinder 91 of the oil pump 87 via a compression spring 95, and the plunger 96 can be driven by an oil pump cam 97 integrally formed at one end of the intake camshaft 12. It is like this.

A cylinder 98 of an accumulator 88 is horizontally movable downward on the side portions of the cam cap housing 16 and the cam cap 17, and is biased and supported by a compression spring 99. It is fixed by a bolt 94 through. The cylinder 91 of the oil pump 87 and the cylinder 98 of the accumulator 88 have the same diameter and can be shared. Further, the oil control valve 89 for high speed switching and the oil control valve 90 for cylinder switching are mounted on the cylinder head 11.

As shown in FIGS. 3, 4 and 10, the high speed switching oil control valve 89 is directly connected to the main oil pump of the engine (not shown) through the oil passage 100 and also through the oil passage 101. It is connected to the hydraulic passage 62. The cylinder deactivation switching oil control valve 90 is connected to the accumulator 88, the oil pump 87, and the main oil pump via the oil passage 102, and is connected to the hydraulic passage 56 via the oil passage 103. Further, each oil control valve 89, 90 can be operated by a control signal of the engine control unit 104.

The switching mechanism 72 of the valve operating device 32 can also be operated by the hydraulic control device 86 like the valve operating device 31, and the hydraulic passage 77 of the rocker shaft 22 has an oil passage (not shown). The oil control valve 89 is connected via the. Further, as shown in FIG. 3, a hollow plug tube 105 is erected for each cylinder in the cylinder head 11, and an ignition plug 106 is mounted inside each plug tube 105. The tip end faces the inside of each combustion chamber 85.

The operation of the V-type 6-cylinder engine of this embodiment will be described below. The engine control unit 104 detects the operating state of the engine based on the detection results of various sensors, and if the engine is running at a low speed, it selects a cam profile suitable for it. In this case, the engine control unit 104 outputs a control signal to the oil control valves 89 and 90 to close the valves 89 and 90. Then, pressure oil is not supplied to the hydraulic passages 56, 62, 77, and the valve operating device 31 causes the low speed rocker arm 34 and the rocker shaft 22 to move by the lock pin 52, as shown in FIG. The locker arm 35 for high speed and the rocker shaft 22 are disengaged from each other. Therefore, when the cam shafts 12 and 13 rotate, the low speed cam 14 causes the low speed rocker arm 34 to swing, and the driving force thereof is transmitted to the main rocker arm 33 via the rocker shaft 22 to cause the main rocker arm 33 to move. It swings, and the pair of adjusting screws 36 at the swinging end drive the intake valve 79 and the exhaust valve 80. On the other hand, as shown in FIG. 12, the valve operating device 32 causes the low speed cam 14 to rotate by the low speed cam 14 when the engagement between the high speed rocker arm 65 and the rocker shaft 22 is released and the cam shafts 12 and 13 rotate. 64 swings, and the pair of adjusting screws 67 at the swinging end drive the intake valve 79 and the exhaust valve 80. In this way, the intake valve 79 and the exhaust valve 80 are driven at the valve opening / closing timing corresponding to the low speed operation, and the engine is operated at the low speed.

When the engine control unit 104 detects the high speed running state of the engine, the engine control unit 104 outputs a control signal to the oil control valves 89 and 90 to open the valves 89 and 90. Then, the pressure oil is supplied to the hydraulic passages 56, 62, 77, and when the engine is traveling at high speed, the valve gear 31 is engaged with the lock pin 52 by the pressure oil as shown in FIG. 11 (b). The low speed rocker arm 34 is disengaged from the rocker shaft 22 by pulling out from the hole 55. Further, the lock pin 59 engages with the engagement hole 61, and the high speed rocker arm 35 and the rocker shaft 22 are integrated. Accordingly, the high speed cam 15 swings the high speed rocker arm 35, and further swings the main rocker arm 33 to drive the intake valve 79 and the exhaust valve 80. On the other hand, in the valve gear 32, the lock pin 59 is engaged with the engagement hole 76 by the supplied pressure oil, and the high speed rocker arm 65 and the rocker shaft 22 are integrated. Therefore, the high-speed cam 15 swings the high-speed rocker arm 35 to drive the intake valve 79 and the exhaust valve 80. In this way, the intake valve 79 and the exhaust valve 80 are driven at the valve opening / closing timing corresponding to high speed operation, and the engine is operated at high speed.

Then, when the engine control unit 104 detects an idle operation state or a low load running state of the engine, two of the four cylinders are stopped to reduce fuel consumption. That is, the engine control unit 104 outputs a control signal to each oil control valve 89, 90 to open only the valve 90. Then, the pressure oil is supplied to the hydraulic passage 56, and the valve operating device 31 releases the engagement between the low speed rocker arm 34 and the rocker shaft 22 as shown in FIG. 11 (c). Therefore, the driving force of the low speed cam 14 and the high speed cam 15 is not transmitted to the main rocker arm 33, and the valve operating device 31 does not operate and is in the cylinder deactivated state. On the other hand, in the valve operating device 32, the low speed cam 14 causes the low speed rocker arm 64 to swing to drive the intake valve 79 and the exhaust valve 80. In this way, the engine is operated by driving only the intake valve 79 and the exhaust valve 80 of the valve gear 32.

As described above, in the engine valve operating system of this embodiment, the oil pressure control device 86 for operating the switching mechanisms 50 and 72 of the valve operating devices 31 and 32 includes the oil pump 87, the accumulator 88, and the oils. This hydraulic control device 86 is composed of control valves 89, 90, etc., and is provided in the space of the axial end portions of the camshafts 12, 13 arranged corresponding to the left and right offset rows of the cylinders 3. Since the oil pump 87 and the accumulator 88 are provided above and below the intake camshaft 12 and the exhaust camshaft 13, the oil pump 87 and the accumulator 88 can be efficiently arranged and the cylinder The layout of the head 11 becomes compact, so that a part of the engine does not project upward and the height does not become high.

Although the internal combustion engine has been described as the V-type 6-cylinder engine in the above-described embodiments, the V-type multi-cylinder internal combustion engine in which the two rows of cylinders are arranged at a predetermined angle with respect to the crankshaft is described. Any organization is acceptable. Further, although the hydraulic control device 86 is provided inside the cylinder head 11, it may be provided outside.

[0044]

[Effect of the device]

 As described above in detail with reference to the embodiments, according to the valve operating system for an internal combustion engine of the present invention, a multi-cylinder internal combustion engine in which two rows of cylinders are arranged at a predetermined angle with respect to the crankshaft. In the above, a pair of cam shafts and a pair of rocker shafts, which are provided with low speed cams and high speed cams and are axially offset from each other corresponding to the two rows of cylinders, respectively, are provided, and the rocker shafts are rocked. The main rocker arm whose moving end faces the upper end of the intake or exhaust valve and is engaged with one of the low speed cam and the high speed cam is integrally mounted, and the other of the low speed cam and the high speed cam is attached. A lock pin that rotatably mounts a sub rocker arm that engages, is movable in a through hole in the rocker shaft, and engages and disengages with the sub rocker arm. Since this hydraulic control device is provided in a space formed by offsetting each camshaft, a part of the internal combustion engine is projected upward or its height is increased. The hydraulic control device can be efficiently arranged without changing the size of the internal combustion engine as a whole, and the layout of the cylinder head can be made compact to reduce the size of the internal combustion engine.

[Brief description of drawings]

FIG. 1 is a plan view of a cylinder head showing a valve operating system for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a sectional view taken along line CC of FIG.

FIG. 5 is a plan view of a valve train having a cylinder deactivation mechanism.

6 is a cross-sectional view taken along the line DD of FIG.

7 is a cross-sectional view taken along line EE of FIG.

FIG. 8 is an exploded perspective view of a valve train.

FIG. 9 is a cross-sectional view showing a switching mechanism of a valve train.

FIG. 10 is a hydraulic path diagram of a valve train.

FIG. 11 is an operation explanatory view of the switching mechanism.

FIG. 12 is a cross-sectional view of a valve train without a cylinder deactivation mechanism.

FIG. 13 is a graph showing operating hydraulic pressure when the internal combustion engine is deactivated.

FIG. 14 is a plan view of a cylinder head representing a valve operating system for an engine having a conventional cylinder deactivation mechanism.

FIG. 15 is a hydraulic path diagram of a conventional valve gear.

[Explanation of symbols]

2 Crank shaft 3 Cylinder 11 Cylinder head 12,13 Cam shaft 14 Low speed cam 15 High speed cam 21,22 Rocker shaft 31,32 Valve system 33 Main rocker arm 34,64 Low speed rocker arm (sub rocker arm) 35, 65 High-speed rocker arm (sub rocker arm) 42, 43, 71 Lost motion 50, 72 Switching mechanism 51, 58, 73 Through hole 52, 59, 74 Lock pin 55, 61, 76 Engagement hole 56, 62, 77 Hydraulic pressure Passage 79 Intake valve 80 Exhaust valve 86 Hydraulic control device 87 Oil pump 88 Accumulator 89 Oil control valve for high-speed switching 90 Oil control valve for cylinder switching 104 Engine control unit

Claims (1)

[Scope of utility model registration request] 1. In a multi-cylinder internal combustion engine in which two rows of cylinders are arranged at a predetermined angle with respect to a crankshaft, a low speed cam and a high speed cam are mounted to correspond to each of the two rows of cylinders. A pair of cam shafts arranged axially offset from each other, a pair of rocker shafts arranged in parallel with the respective cam shafts, a base end of which is integrally attached to the rocker shaft, and a swing end of which is A main rocker arm that faces the upper end of the intake or exhaust valve and is engaged with either the low speed cam or the high speed cam, and the base end is rotatably attached to the rocker shaft. The sub rocker arm with which the other of the cams engages, and the sub rocker arm provided movably in a through hole along the radial direction in the rocker shaft. A lock pin that engages and disengages with a rocker arm, and a hydraulic control device that controls the operation of the lock pin by setting the hydraulic pressure to a hydraulic passage that is provided along the axial direction at the axial center of the rocker shaft, A valve operating system for an internal combustion engine, wherein the hydraulic control device is disposed in a space formed by offsetting the camshafts.