JP2011163134A - Engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine capable of changing the opening/closing timing of an intake valve by a simple structure. <P>SOLUTION: The engine 1 includes a variable valve timing mechanism 37 changing the valve closing timing of the intake valve 16. The variable valve timing mechanism 37 is provided with: a camshaft 90; a first cam 91 and a second cam 92 provided at the camshaft 90; a first swing arm 50 made to abut on the first cam 91 and swung following the rotation of the first cam 91; a second swing arm 60 made to abut on the second cam 92 and swung following the rotation of the second cam 92; a push rod 70 connected to the first swing arm 50 and linking the first swing arm 50 to the intake valve 16; and a switching means 100 performing switching to a first state for swinging the first swing arm 50 following the rotation of the first cam 91 and a second state for swinging the first swing arm together with the second swing arm 60 following the rotation of the second cam 92. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine technology that employs a so-called Miller cycle in which an intake valve is closed earlier or later than when a piston reaches an intake bottom dead center.

  2. Description of the Related Art Conventionally, there has been known an engine technology that employs a so-called mirror cycle in which an intake valve is closed at a time earlier or later than a time when a piston reaches an intake bottom dead center.

  For example, as disclosed in Patent Document 1, there is an engine that employs a so-called delayed closing type mirror cycle in which an intake valve is closed at a time later than a time when a piston reaches an intake bottom dead center. In this engine, by adopting a slow-closed mirror cycle, it is possible to increase only the expansion ratio of the exploded fuel gas while keeping the compression ratio of the sucked air small, and to obtain high thermal efficiency. it can.

  As another method of the mirror cycle, there is an engine that employs a so-called early closing type mirror cycle in which the intake valve is closed earlier than the time when the piston reaches the bottom dead center. In this engine, by adopting a mirror cycle of an early closing method, air can be adiabatically expanded in the cylinder to lower the combustion temperature. Therefore, high thermal efficiency can be obtained and the amount of NOx generated can be reduced.

  When an early-closed mirror cycle is adopted for an engine, the amount of air sucked into the engine is reduced, and the deterioration of performance such as an increase in generated black smoke and deterioration of acceleration and startability is expected. Therefore, in this case, the amount of air sucked into the engine is increased by increasing the pressure ratio of the supercharger that is driven by the exhaust gas of the engine, pressurizes the air, and sends it into the cylinder of the engine. Reduction can be prevented and performance deterioration can be prevented.

  However, when the engine is operated at a low load, the amount of exhaust gas from the engine is small, so that the supercharger cannot be driven sufficiently, and the pressure ratio of the supercharger cannot be made higher than before. In this case, a sufficient amount of air sucked into the engine cannot be ensured, and the engine performance may deteriorate.

  In order to prevent such deterioration of the engine performance, it is necessary to change the closing timing of the intake valve in accordance with the load state of the engine or the like to ensure the amount of air sucked into the engine. However, the closing timing of the intake valve is determined by the cam profile of the cam that opens and closes the intake valve. For this reason, in order to change the valve closing timing of the intake valve, it is disadvantageous in that it requires a complicated structure such as providing a mechanism for changing the relative angle between the cam and the cam shaft on which the cam is formed. It was.

JP-A-8-291715

  The present invention has been made in view of the above situation, and provides an engine that can change the opening and closing timing of an intake valve with a simple structure.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  In other words, the present invention is an engine including a variable valve timing mechanism capable of changing the closing timing of the intake valve, the variable valve timing mechanism including a camshaft that rotates in conjunction with a crankshaft, and the cam A first cam and a second cam provided on a shaft and having different cam profiles; a first swing arm which is in contact with the first cam and swings according to the rotation of the first cam; and the second cam A second swing arm that swings in accordance with rotation of the second cam, a push rod that is connected to the first swing arm and links the first swing arm and the intake valve, A first state in which the first swing arm is swung in accordance with the rotation of the first cam; and a second state in which the first swing arm is swung in accordance with the rotation of the second cam together with the second swing arm; Those comprising a switchable switching means.

  According to a second aspect of the present invention, the switching means includes the receiving member attached to the second swing arm and the first swing arm attached to the first swing arm, thereby bringing the first swing arm into contact with the receiving member. And a hydraulic actuator that is separated from the first cam and that can be operated integrally with the second swing arm.

  According to a third aspect of the present invention, the switching means operates the hydraulic actuator using lubricating oil supplied to each part of the engine.

  According to a fourth aspect of the present invention, the lubricating oil for operating the hydraulic actuator is formed on a hydraulic actuator operating oil passage formed on the first swing arm and on a swing arm shaft that supports the first swing arm in a swingable manner. Is supplied to the hydraulic actuator via the first oil passage.

  According to a fifth aspect of the present invention, the first swing arm is rotatably supported and includes a cam roller that comes into contact with the first cam. The lubricating oil that lubricates the cam roller is oil for operating the hydraulic actuator. A roller lubricating oil passage formed in the first swing arm separately from the passage and a second oil passage formed in the swing arm shaft separately from the first oil passage are supplied to the cam roller. Is.

  According to a sixth aspect of the present invention, a switching valve for switching the operation of the hydraulic actuator is attached to the first swing arm.

  In claim 7, at least one cam profile of the cam profile of the first cam or the cam profile of the second cam is set so that the intake valve is closed earlier than the intake bottom dead center. Is.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect, the intake valve can be opened and closed by cams having different cam profiles, and the opening / closing timing of the intake valve can be changed to the timing corresponding to each cam. In this case, the opening / closing timing of the intake valve can be switched with a simple configuration, the number of parts and the number of assembly steps can be reduced, and the manufacturing cost can be reduced. Further, by reducing the number of parts and the number of assembly steps, it is possible to suppress the occurrence of dimensional errors and errors during assembly, and thus improve the reliability of the engine as a whole.

  In claim 2, the switching means can be configured simply. Therefore, it is possible to reduce the number of parts and assembly man-hours, and to reduce the manufacturing cost.

  In claim 3, since the switching means can be operated using engine lubricating oil, there is no need to use a separate hydraulic pump or the like, and it is possible to reduce the number of parts and the number of assembling steps. Reduction can be achieved.

  According to the fourth aspect of the present invention, it is not necessary to separately provide piping or the like for supplying lubricating oil for operating the hydraulic actuator, and it is possible to reduce the number of parts and the number of assembly steps. Further, the supply of the lubricating oil to the hydraulic actuator is not affected by the swing of the first swing arm. Therefore, the lubricating oil can be stably supplied to the hydraulic actuator.

  According to the fifth aspect of the present invention, it is not necessary to separately provide piping or the like for supplying lubricating oil for lubricating the cam roller, and it is possible to reduce the number of parts and the number of assembly steps. Further, the lubricating oil is supplied to the cam roller via an oil path different from that of the hydraulic actuator. Accordingly, it becomes possible to stably supply the lubricating oil to the cam roller, and the cam roller can be reliably lubricated.

  In claim 6, it is possible to reduce the number of parts and assembly man-hours. Further, the switching means can be configured compactly, and space saving can be achieved.

  According to the seventh aspect, by advancing the closing timing of the intake valve, the air can be adiabatically expanded in the cylinder and the combustion temperature can be lowered. As a result, the amount of NOx generated can be reduced.

1 is a cross-sectional view showing an engine according to an embodiment of the present invention. The schematic diagram which showed the mode of the connection of an engine and a supercharger. Front sectional drawing which showed the 1st swing arm of the variable valve timing mechanism. The top view which showed the variable valve timing mechanism. The bottom view which showed the variable valve timing mechanism. The front view which showed the 2nd swing arm of the variable valve timing mechanism. The front view which showed a mode that both the 1st swing arm and the 2nd swing arm rocked upwards in the 1st state. The front view which showed a mode that only the 1st swing arm was rock | fluctuated below in a 1st state. The figure which showed the opening / closing timing of the intake valve in a 1st state. (A) The figure which showed the relationship between a crank angle and the opening / closing timing of an intake valve. (B) The figure which showed the relationship between a crank angle and the valve lift of an intake valve. The front sectional view showing the first swing arm of the variable valve timing mechanism in the second state. The front view which showed a mode that both the 1st swing arm and the 2nd swing arm rocked upwards in the 2nd state. The front view which showed a mode that the 1st swing arm was rock | fluctuated according to the 2nd swing arm in the 2nd state. The figure which showed the opening / closing timing of the intake valve in a 2nd state. (A) The figure which showed the relationship between a crank angle and the opening / closing timing of an intake valve. (B) The figure which showed the relationship between a crank angle and the valve lift of an intake valve.

  First, the engine 1 which concerns on one Embodiment of this invention is demonstrated using FIG.1 and FIG.2. The engine 1 is a so-called in-line multi-cylinder engine in which a plurality of pistons 31 are arranged in series. In the following description, only one cylinder is described for the sake of simplicity. The number and arrangement of pistons of the engine according to the present invention are not limited to those of the engine 1 according to the present embodiment.

  As shown in FIG. 1, the engine 1 includes an engine body 10 having a cylinder block 11, a cylinder head 13, and the like, a fuel supply unit 20 having a fuel injection nozzle 21, a fuel injection pump 22, and the like, and a piston 31 and a connecting rod 32. , A crankshaft 33, a moving part 30 having a variable valve timing mechanism 37, and the like.

  In the engine main body 10, the cylinder block 11 is provided with a cylinder 11a in the vertical direction so as to penetrate from the upper surface to the lower surface. A cylinder liner 12 having an outer diameter substantially the same as the inner diameter is fitted into the cylinder 11a.

  The cylinder liner 12 is a substantially circular tube-shaped member in which the piston 31 is slidably contacted.

  The cylinder head 13 is fastened to the upper surface of the cylinder block 11 by a head bolt 14 or the like, and the combustion chamber 15 is configured by the cylinder liner 12 and the upper end surface of the piston 31.

  The cylinder head 13 is provided with an intake passage 13a for sending air into the combustion chamber 15 and an intake valve 16 for opening and closing the passage, and an exhaust passage 13b for discharging exhaust gas. An exhaust valve 17 is provided for opening and closing the passage. The cylinder head 13 is provided with two intake valves 16 and 16 and two exhaust valves 17 and 17 for each cylinder. The two intake valves 16, 16 are connected by an intake connecting member 16a, and the two exhaust valves 17, 17 are connected by an exhaust connecting member 17a.

  As shown in FIG. 2, an exhaust turbo supercharger 2 driven using the exhaust gas of the engine 1 is provided in the intake passage 13a and the exhaust passage 13b. The supercharger 2 has a turbine 2a and a compressor 2b attached coaxially to the turbine 2a. The turbine 2a is rotated by exhaust gas supplied from the combustion chamber 15 through the exhaust passage 13b. The rotation of the turbine 2a is transmitted to the compressor 2b mounted on the same axis, and the compressor 2b sucks and compresses the atmosphere and supplies it to the combustion chamber 15 via the intake passage 13a. Thus, the supercharger 2 is configured to be able to forcibly send air into the cylinder 11a using the exhaust energy of the engine 1.

  An intercooler 3 for cooling the air passing through the intake passage 13a is attached downstream of the compressor 2b in the intake passage 13a. The air whose temperature has been increased by being compressed by the supercharger 2 is cooled when passing through the intercooler 3 and supplied to the engine 1.

  As shown in FIG. 1, in the fuel supply unit 20, the fuel injection pump 22 is interlocked and connected to a crankshaft 33 to be described later via a gear and the like, and is driven by the rotational movement of the crankshaft 33 to The fuel is pumped to the fuel injection nozzle 21. The fuel injection pump 22 is disposed on the side of the cylinder block 11 and is connected to the fuel injection nozzle 21 by a fuel pipe.

  The fuel injection nozzle 21 that constitutes the fuel supply unit 20 is provided in the cylinder head 13 so that the tip thereof protrudes into the combustion chamber 15, and fuel is injected into the combustion chamber 15 from the injection port provided in the tip. It is to be jetted. The fuel injection nozzle 21 is configured to be able to inject the fuel supplied from the fuel injection pump 22 in accordance with the operating state of the engine 1.

  In the moving part 30, the piston 31 is provided in the cylinder liner 12 so as to be slidable in the vertical direction as described above. The piston 31 is formed in a substantially cylindrical shape with, for example, an aluminum alloy or cast iron. A piston pin 31 a is provided at a midway portion in the vertical direction of the piston 31 so as to intersect perpendicularly to the axial direction of the cylinder liner 12 and to be parallel to the axial direction of a crankshaft 33 described later.

  The connecting rod 32 has cylindrical members at both upper and lower ends. The upper end of the connecting rod 32 is inserted into a piston pin 31 a provided in the piston 31 so as to be swingable. And the lower end of the connecting rod 32 is inserted in the crankpin 33a of the crankshaft 33 so that rotation is possible.

  The crankshaft 33 is disposed in a direction perpendicular to the axial direction of the cylinder liner 12 at the lower part of the cylinder block 11. Since the crankshaft 33 is connected to the piston 31 by the connecting rod 32, the reciprocating motion of the piston 31 in the vertical direction is transmitted to the crankshaft 33 via the connecting rod 32, so that the crankshaft 33 rotates. Converted.

  The crankshaft 33 is pivotally supported by a metal cap 35. The metal cap 35 is fastened to the lower part of the cylinder block 11 with a cap bolt 35a or the like.

  The variable valve timing mechanism 37 includes a cam, a swing arm, a push rod, a valve arm, and the like for opening and closing the intake valve 16 and the exhaust valve 17, respectively. The variable valve timing mechanism 37 includes a camshaft 90, a first swing arm 50, a push rod 70, a valve arm 80, and the like as a mechanism for opening and closing the intake valve 16, and is driven in conjunction with the rotational movement of the crankshaft. Then, the intake valve 16 is opened and closed.

  The camshaft 90 is disposed in parallel with the axial direction of the crankshaft 33 and is interlocked and connected to the crankshaft 33 via a gear or the like. The camshaft 90 is rotationally driven by the rotational movement of the crankshaft 33, and the first swing arm 50 swings according to the cam profiles of the first cam 91 and the second cam 92 (see FIG. 3) formed on the camshaft 90. .

  The push rod 70 penetrates the cylinder head 13 from the inside of the cylinder block 11 and extends upward. The lower end of the push rod 70 is connected to the first swing arm 50, and the upper end thereof is connected to one end of the valve arm 80. The valve arm 80 is swingably supported by a valve arm shaft 81 disposed so as to be parallel to the cam shaft 90. The other end of the valve arm 80 is connected to an intake connecting member 16 a disposed at the upper end of the intake valve 16.

  A cam for the exhaust valve 17 is also formed on the cam shaft 90. A swing arm (not shown) is swung according to the cam profile of the cam, and the exhaust valve 17 is moved via a push rod and a valve arm (not shown). It connects with the exhaust connection member 17a arrange | positioned at an upper end.

  Next, an operation mode during operation of the engine 1 will be briefly described.

  The engine 1 is a four-cycle engine in which the operation mode during operation includes four steps of an intake process, a compression process, an expansion process, and an exhaust process, and the entire process is completed when the crankshaft 33 rotates twice. Further, the entire configuration is completed when the camshaft 90 rotates once.

  In the intake process, the exhaust valve 17 provided in the cylinder head 13 is closed, while the intake valve 16 is opened and the piston 31 is slid downward, so that the outside of the engine 1 passes through the intake passage 13a. This is a step of sucking air into the cylinder 11a. In the intake process, air compressed by the supercharger 2 and cooled by the intercooler 3 is supplied into the combustion chamber 15.

  The compression step is a step of compressing the air in the cylinder 11a by closing the intake valve 16 with the exhaust valve 17 closed and sliding the piston 31 upward. When fuel is injected from the fuel injection nozzle 21 into the air that has been compressed by this compression step and has become high temperature and high pressure, the fuel is dispersed in the combustion chamber 15 and starts combustion. When the fuel burns, the pressure in the combustion chamber 15 increases.

  The expansion stroke is a step of pushing the piston 31 downward again by the pressure increased in the combustion chamber 15 in the compression step. By pushing down the piston 31 in this way, a driving force is applied to the crankshaft 33.

  In the exhaust process, the exhaust valve 17 is opened while the intake valve 16 is closed, and the piston 31 is slid upward to discharge the exhaust gas in the cylinder 11a to the outside through the exhaust passage 13b. It is. The exhaust gas passes through the turbine 2a of the supercharger 2 in the middle of the exhaust passage 13b, and rotates the turbine 2a.

  Opening and closing of the intake valve 16 and the exhaust valve 17 in each of the above steps is performed in conjunction with the rotational movement of the crankshaft 33 by the variable valve timing mechanism 37. Thus, in each of the above steps, the intake valve 16 and the exhaust valve 17 can be opened and closed at a predetermined time.

  Next, the variable valve timing mechanism 37 will be described in detail.

  As shown in FIGS. 3 to 6, the variable valve timing mechanism 37 opens and closes the intake valve 16 at a predetermined timing and switches the opening and closing timing of the intake valve 16 according to the operating state of the engine 1. . The variable valve timing mechanism 37 includes a swing arm shaft 40, a first swing arm 50, a second swing arm 60, a push rod 70, a cam shaft 90, a switching means 100, and the like.

  As shown in FIGS. 3 to 5, the swing arm shaft 40 is a cylinder parallel to the axial direction of the crankshaft 33 (hereinafter, the axial direction of the crankshaft 33 is defined as “front-rear direction”). It is a columnar member that is horizontally mounted on the block 11.

  The first swing arm 50 is a member formed in a substantially rectangular parallelepiped shape, and is arranged with its longitudinal direction as the left-right direction. The central lower surface in the longitudinal direction of the first swing arm 50 is formed in a concave shape. A first through hole 50a is formed in the front-rear direction at one end (left end) of the first swing arm 50 in the longitudinal direction. The swing arm shaft 40 is inserted into the first through hole 50a, and the first swing arm 50 is swingably supported by the swing arm shaft 40. A first groove 50b is formed at the lower end of the first swing arm 50 in the longitudinal direction at the other end (right end). A first cam roller 52, which is a cam roller, is installed in the first groove portion 50b so as to protrude downward from the lower surface of the other end of the first swing arm 50, and is rotatably supported by the first roller shaft 51 in the front-rear direction. Is done. On the upper surface of the other end of the first swing arm 50, a rod support member 53 having a hemispherical concave portion recessed upward is attached.

  As shown in FIGS. 4 to 6, the second swing arm 60 is a member formed in a substantially rectangular parallelepiped shape, and is arranged side by side with the first swing arm 50 in the longitudinal direction thereof in the left-right direction. A second through hole 60a is formed in the front-rear direction at one end of the second swing arm 60 in the longitudinal direction. The swing arm shaft 40 is inserted into the second through hole 60a, and the second swing arm 60 is swingably supported by the swing arm shaft 40 in a state adjacent to the first swing arm 50. A second groove 60b is formed at the lower end of the second swing arm 60 in the longitudinal direction. The second cam roller 62 is installed in the second groove portion 60b so as to protrude downward from the lower surface of the other end of the second swing arm 60, and is rotatably supported by the second roller shaft 61 in the front-rear direction.

  As shown in FIGS. 1 and 3, the push rod 70 is a substantially cylindrical member, and interlocks and connects the first swing arm 50 and the valve arm 80. The lower end of the push rod 70 is formed in a hemispherical shape, and is fitted to the recess of the rod support member 53 of the first swing arm 50 so as to be swingable. The upper end of the push rod 70 is fitted to one end of the valve arm 80 so as to be swingable.

  As shown in FIG. 1, the valve arm 80 connects the push rod 70 and the intake connecting member 16a. The valve arm 80 is swingably supported by a valve arm shaft 81 that is horizontally mounted in the front-rear direction. One end of the valve arm 80 is connected to the upper end of the push rod 70, and the other end is connected to the intake connection member 16a.

  As shown in FIGS. 3 and 6, the cam shaft 90 is disposed to extend in the front-rear direction below the other ends of the first swing arm 50 and the second swing arm 60 in the longitudinal direction. The camshaft 90 is interlocked and connected to the crankshaft 33 through a gear or the like, and rotates when the crankshaft 33 rotates. A first cam 91 and a second cam 92 having a cam profile different from that of the first cam 91 are formed on the cam shaft 90 at predetermined intervals in the axial direction (front-rear direction). The first cam 91 is disposed on the cam shaft 90 so as to contact the first cam roller 52 of the first swing arm 50 from below. The second cam 92 is disposed on the cam shaft 90 so as to contact the second cam roller 62 of the second swing arm 60 from below.

  As shown in FIGS. 3 to 5, the switching means 100 switches the operating states of the first swing arm 50 and the second swing arm 60 and consequently the opening / closing timing of the intake valve 16. The switching means 100 includes an electromagnetic switching valve 110, a check valve 120, a hydraulic piston 130, a switching valve 140, a receiving member 150, a control device 160, and the like, and these members, the swing arm shaft 40, and the first swing arm 50. It is comprised by the oil path formed in.

  As shown in FIG. 4, the electromagnetic switching valve 110 is a valve that communicates the suction port and the discharge port when receiving a control signal, and shuts off the suction port and the discharge port when not receiving the control signal. A suction port of the electromagnetic switching valve 110 is connected to a hydraulic pump 4 as lubricating oil supply means driven by the crankshaft 33. The hydraulic pump 4 sucks and pumps lubricating oil stored in an oil pan (not shown). Lubricating oil pumped by the hydraulic pump 4 is supplied to the intake port of the electromagnetic switching valve 110, and each part of the engine 1 (for example, the valve arm shaft 81, the crankpin 33a, etc.) via an oil passage (not shown). To lubricate each part.

  The swing arm shaft 40 is formed with a first oil passage 40a, a second oil passage 40b, a first outer oil passage 40c, a second outer oil passage 40d, a third outer oil passage 40e, and a fourth outer oil passage 40f. The

  The first oil passage 40a and the second oil passage 40b are formed inside the swing arm shaft 40 so as to be arranged in front and back in parallel with the axial direction thereof. The first outer peripheral oil passage 40c, the second outer peripheral oil passage 40d, and the third outer peripheral oil passage 40e are opposed to the inner peripheral surface of the first through hole 50a of the first swing arm 50 among the outer peripheral surfaces of the swing arm shaft 40. Are formed in a ring shape at predetermined intervals in the axial direction. The fourth outer peripheral oil passage 40f is formed in an annular shape at a position facing the inner peripheral surface of the second through hole 60a of the second swing arm 60 in the outer periphery of the swing arm shaft 40. The first oil passage 40a is connected to the first outer oil passage 40c and the second outer oil passage 40d, and is not connected to the second oil passage 40b. The second oil passage 40b is connected in communication with the third outer oil passage 40e and the fourth outer oil passage 40f. The first oil passage 40a is connected in communication with the discharge port of the electromagnetic switching valve 110. The second oil passage 40b is connected to the hydraulic pump 4 through an oil passage (not shown). That is, the first oil passage 40a and the second oil passage 40b are connected to the hydraulic pump 4 through separate oil passages.

  As shown in FIGS. 3 and 4, the first swing arm 50 includes a first roller lubrication oil passage 50c that is a roller lubrication oil passage, a piston actuation oil passage 50d that is a hydraulic actuator actuation oil passage, and a piston. A hole 50e, a switching valve hole 50f, and a switching oil passage 50g are formed.

  The first roller lubricating oil passage 50 c is formed inside the first swing arm 50 along the longitudinal direction of the first swing arm 50. One end of the first roller lubricating oil passage 50 c is communicated with the third outer peripheral oil passage 40 e of the swing arm shaft 40, and the other end is communicated with the first cam roller 52 in the first groove portion 50 b of the first swing arm 50. .

  The piston operating oil passage 50 d is formed inside the first swing arm 50 along the longitudinal direction of the first swing arm 50. One end of the piston operating oil passage 50 d communicates with the second outer peripheral oil passage 40 d of the swing arm shaft 40, and the other end communicates with the first groove portion 50 b of the first swing arm 50. A check valve 120, a hydraulic piston 130, and a switching valve 140 are provided in the middle of the piston operating oil passage 50d.

  The check valve 120 allows the lubricating oil to flow only from the first outer peripheral oil passage 40c side to the first groove portion 50b side and prevents the lubricating oil from flowing from the first groove portion 50b side to the first outer peripheral oil passage 40c side. It is.

  The hydraulic piston 130 is a hydraulic actuator disposed in a piston hole 50e formed between the check valve 120 and the first groove 50b of the first swing arm 50. The piston hole 50 e is a columnar hole that forms a part of the piston operating oil passage 50 d and is formed to open downward from the first swing arm 50. The hydraulic piston 130 has a hemispherical bottom and is disposed in the piston hole 50e so as to be slidable in the vertical direction.

  The switching valve 140 is disposed in a switching valve hole 50f formed between the piston hole 50e of the first swing arm 50 and the first groove 50b. The switching valve hole 50f is a cylindrical hole that is part of the piston operating oil passage 50d and the switching oil passage 50g and is formed to open upward from the first swing arm 50. The switching valve 140 is slidably disposed in the switching valve hole 50f in the vertical direction, and is biased upward by the spring 54. The upper end portion of the switching valve hole 50f is closed by a bolt 55. When the switching valve 140 is slid upward by the urging force of the spring 54, the piston operating oil passage 50d is communicated to allow the lubricating oil to flow from the piston hole 50e to the first groove 50b. .

  The switching oil passage 50 g is formed inside the first swing arm 50 along the longitudinal direction of the first swing arm 50. One end of the switching oil passage 50g communicates with the first outer peripheral oil passage 40c of the swing arm shaft 40, and the other end communicates with the switching valve hole 50f near the upper portion of the switching valve 140.

  As shown in FIGS. 4 and 6, a second roller lubricating oil passage 60 c is formed in the second swing arm 60.

  The second roller lubricating oil passage 60 c is formed inside the second swing arm 60 along the longitudinal direction of the second swing arm 60. One end of the second roller lubrication oil passage 60 c communicates with the fourth outer peripheral oil passage 40 f of the swing arm shaft 40, and the other end communicates above the second cam roller 62 in the second groove 60 b of the second swing arm 60. .

  As shown in FIGS. 5 and 6, the receiving member 150 is a plate-like member attached to the lower surface of the second swing arm 60. The receiving member 150 extends from the lower side of the second swing arm 60 to the lower side of the first swing arm 50 toward the front. The extending end of the receiving member 150 is disposed so as to overlap the piston hole 50e of the first swing arm 50 and to face the recessed portion on the lower surface of the first swing arm 50 in a bottom view.

  As shown in FIG. 4, the control device 160 controls the electromagnetic switching valve 110 based on various signals and programs. The control device 160 includes a central processing unit, a storage device, and the like. The control device 160 is connected to the fuel injection amount detection means 161, the engine speed detection means 162, and the electromagnetic switching valve 110.

  The fuel injection amount detection means 161 detects the amount of fuel (fuel injection amount) injected from the fuel injection nozzle 21 into the combustion chamber 15. Specifically, the fuel injection amount detection means 161 is a rack position sensor that detects the position of the rack that adjusts the amount of fuel injected by the fuel injection nozzle 21.

  The engine speed detecting means 162 detects the speed of the engine 1.

  The control device 160 stores an output map for calculating the output of the engine 1 from the fuel injection amount detected by the fuel injection amount detection means 161 and the engine speed detected by the engine speed detection means 162. The The control device 160 calculates the output of the engine 1 based on the fuel injection amount, the engine speed, and the output map, and determines whether the engine 1 is operating at a high output (high load) or a low output (low load). Determine if you are driving in A threshold value for distinguishing between a high load and a low load is determined in advance by experiment, numerical calculation, or the like.

  When it is determined that the engine 1 is operating at a high load, the control device 160 does not transmit a control signal to the electromagnetic switching valve 110 and blocks the intake port and the discharge port of the electromagnetic switching valve 110. Further, when the control device 160 determines that the engine 1 is operating at a low load, the control device 160 transmits a control signal to the electromagnetic switching valve 110 to connect the intake port and the discharge port of the electromagnetic switching valve 110.

  Next, an operation mode of the variable valve timing mechanism 37 configured as described above will be described. First, the case where the engine 1 is operating at a high load will be described.

  When it is determined that the engine 1 is operating at a high load, the control device 160 shuts off the intake port and the discharge port of the electromagnetic switching valve 110 (hereinafter, this state is referred to as “first state”). Therefore, the lubricating oil from the hydraulic pump 4 is not supplied to the first oil passage 40a of the swing arm shaft 40. On the other hand, since the hydraulic pump 4 communicates with the second oil passage 40b of the swing arm shaft 40 through an oil passage (not shown), the lubricating oil from the hydraulic pump 4 passes through the second outer passage 40b to the third outer periphery. It is supplied to the oil passage 40e and the fourth outer peripheral oil passage 40f. The lubricating oil supplied to the third outer peripheral oil passage 40 e is supplied to the first groove portion 50 b via the first roller lubricating oil passage 50 c of the first swing arm 50 and lubricates the first cam roller 52. Further, the lubricating oil supplied to the fourth outer peripheral oil passage 40 f is supplied to the second groove portion 60 b via the second roller lubricating oil passage 60 c of the second swing arm 60 and lubricates the second cam roller 62. .

  When the cam shaft 90 rotates in this state, the first cam roller 52 rotates while contacting the first cam 91, so that the first swing arm 50 swings around the swing arm shaft 40 according to the cam profile of the first cam 91. To do. Further, since the second cam roller 62 rotates while contacting the second cam 92, the second swing arm 60 swings about the swing arm shaft 40 as a fulcrum according to the cam profile of the second cam 92.

  Here, the cam profile of the 1st cam 91 and the 2nd cam 92 is demonstrated using FIG.3 and FIG.6. The convex portion 91a of the first cam 91 has a front slope 91b and a rear slope 91c. The convex portion 92a of the second cam 92 has a front slope 92b and a rear slope 92c. The front slope 91b and the front slope 92b are formed so as to substantially coincide with each other in a front view. The distance between the front slope 92b and the rear slope 92c is formed to be larger than the distance between the front slope 91b and the rear slope 91c.

  As shown in FIG. 7, the first cam 91 and the second cam 92 rotate in the direction of the white arrow with the first cam roller 52 and the second cam roller 62 in contact with the front slope 91b and the front slope 92b, respectively. Then, the first swing arm 50 and the second swing arm 60 first swing upward simultaneously according to the shape of the front slope 91b and the front slope 92b. When the first swing arm 50 swings upward, the intake valve 16 is opened via the push rod 70, the valve arm 80, and the intake coupling member 16a (see FIG. 1).

  Thereafter, as shown in FIG. 8, when the first cam 91 and the second cam 92 are further rotated in the direction of the white arrow, the first swing arm 50 precedes the second swing arm 60 in accordance with the shape of the rear slope 91c. Swings downward. At this time, the first swing arm 50 does not need to come into contact with the receiving member 150 of the second swing arm 60 that has been swung upward due to the recessed portion on the lower surface thereof. Not disturbed. After the first swing arm 50 swings downward, the second swing arm 60 swings downward according to the shape of the rear slope 92c. When the first swing arm 50 swings downward, the intake valve 16 is closed (see FIG. 1). That is, the first swing arm 50 and the second swing arm 60 operate separately, and the operation of the first swing arm 50 determines the closing timing of the intake valve 16 regardless of the operation of the second swing arm 60. .

  As shown in FIG. 9, the cam profile of the first cam 91 is the timing of the intake valve 16 at an earlier time (S1) than the top dead center (hereinafter referred to as “intake top dead center”) T in the intake process of the piston 31. The valve opening is started so that the valve lift of the intake valve 16 is maximized at the intake top dead center T of the piston 31, and the bottom dead center in the intake process of the piston 31 (hereinafter referred to as "intake bottom dead center"). ) The closing of the intake valve 16 is started at a time earlier than B, and the intake valve 16 is set to be completely closed at a time earlier than the intake bottom dead center B of the piston 31 (S2). That is, by opening and closing the intake valve 16 according to the cam profile of the first cam 91, a so-called early closing type mirror cycle can be realized.

  Next, a case where the engine 1 is operating at a low load will be described.

  As shown in FIG. 10, when the control device 160 determines that the engine 1 is operating at a low load, the control device 160 communicates the suction port and the discharge port of the electromagnetic switching valve 110 (hereinafter, this state is referred to as “second state”). Status ”). Accordingly, the lubricating oil from the hydraulic pump 4 is supplied to the first oil passage 40 a of the swing arm shaft 40. The lubricating oil supplied to the first oil passage 40a is supplied to the switching oil passage 50g via the first outer oil passage 40c, and to the piston operating oil passage 50d via the second outer oil passage 40d. Supplied. Since the hydraulic pump 4 communicates with the second oil passage 40b of the swing arm shaft 40 via an oil passage (not shown), the lubricating oil is supplied to the first groove 50b and the first groove as in the first state. The first cam roller 52 and the second cam roller 62 are lubricated by being supplied to the two groove portions 60b.

  The lubricating oil supplied to the switching oil passage 50g is supplied above the switching valve 140 in the switching valve hole 50f, that is, between the switching valve 140 and the bolt 55. Therefore, when the switching valve 140 is pressed downward by the lubricating oil and the pressing force exceeds the biasing force of the spring 54, the switching valve 140 slides downward against the biasing force of the spring 54. . When the switching valve 140 slides downward, it closes the piston operating oil passage 50d and blocks the flow of lubricating oil from the piston hole 50e to the first groove 50b.

  The lubricating oil supplied to the piston operating oil passage 50d is supplied to the piston hole 50e via the check valve 120. In the piston operating oil passage 50d, the portion from the piston hole 50e to the first groove 50b is closed by the switching valve 140, so that the hydraulic piston 130 is pressed downward by the lubricating oil supplied to the piston hole 50e. Is done. The hydraulic piston 130 pressed by the lubricating oil slides downward and protrudes from the lower surface of the first swing arm 50. The hydraulic piston 130 protrudes until its lower end comes into contact with the upper surface of the receiving member 150 attached to the second swing arm 60. While the suction port and the discharge port of the electromagnetic switching valve 110 are communicated by the control device 160, the hydraulic piston 130 is held in a state of protruding from the lower surface of the first swing arm 50.

  As shown in FIG. 11, when the cam shaft 90 rotates in this state, the first cam roller 52 rotates while coming into contact with the first cam 91, so that the first swing arm 50 follows the cam profile of the first cam 91. It swings around the shaft 40 as a fulcrum. Further, since the second cam roller 62 rotates while contacting the second cam 92, the second swing arm 60 swings about the swing arm shaft 40 as a fulcrum according to the cam profile of the second cam 92.

  When the first cam 91 and the second cam 92 rotate in the direction of the white arrow with the first cam roller 52 and the second cam roller 62 in contact with the front slope 91b and the front slope 92b, respectively, the first swing arm 50 is rotated. The second swing arm 60 first swings upward simultaneously simultaneously according to the shapes of the front slope 91b and the front slope 92b. When the first swing arm 50 swings upward, the intake valve 16 is opened via the push rod 70, the valve arm 80, and the intake coupling member 16a (see FIG. 1).

  Thereafter, as shown in FIG. 12, the first cam roller 52 reaches the rear inclined surface 91c. However, since the hydraulic piston 130 is in contact with the receiving member 150, the first cam roller 52 is separated from the first cam 91, One swing arm 50 cannot swing downward according to the shape of the rear slope 91c. In this state, the first swing arm 50 swings as the second swing arm 60 swings. That is, when the second swing arm 60 swings downward according to the shape of the rear slope 92c, the first swing arm 50 swings downward as the second swing arm 60 swings. When the first swing arm 50 swings downward, the intake valve 16 is closed (see FIG. 1). That is, when the intake valve 16 is closed, the first swing arm 50 operates integrally with the second swing arm 60, and the operation of the second swing arm 60 determines the valve closing timing of the intake valve 16.

  As shown in FIG. 13, the cam profile of the second cam 92 starts to open the intake valve 16 at a time earlier than the intake top dead center T of the piston 31 (S 1), and the intake top dead center T of the piston 31. In step S3, the intake valve 16 starts to be closed in the vicinity of the intake bottom dead center B of the piston 31 so that the valve lift of the intake valve 16 becomes maximum, and thereafter, the intake valve 16 is completely closed (S3). Is set as follows. In the present embodiment, the closing of the intake valve 16 is started near the intake bottom dead center B of the piston 31, but the present invention is not limited to this. In other words, the intake valve 16 can be closed at the intake bottom dead center B of the piston 31.

  As described above, the control device 160 switches the engine 1 to the first state when the engine 1 is operating at a high load, and to the second state when the engine 1 is operating at a low load. The valve closing timing of the intake valve 16 can be changed according to the operating state. As a result, during high-load operation of the engine 1, even if the intake valve 16 closes earlier than the intake bottom dead center (an early-closed mirror cycle), the air is sufficiently driven into the cylinder 11a by the drive of the supercharger 2. Will be inhaled. On the other hand, when the engine 1 is in a low load operation, the exhaust gas amount is small and the function of the supercharger 2 is reduced compared to that in the high load operation. Therefore, if the intake valve 16 is closed at the same time as in the high load operation The air is not sufficiently sucked into the cylinder 11a. However, in the present embodiment, since the intake valve 16 is closed at a later time than during high load operation, more specifically, near the bottom dead center of intake air, the intake period is longer than that during high load operation, and the air flows into the cylinder 11a. It will be fully inhaled. That is, even when the engine 1 is in a high load operation or a low load operation, a necessary amount of air sucked into the cylinder 11a is secured.

As described above, the engine 1 according to this embodiment is the engine 1 including the variable valve timing mechanism 37 that can change the closing timing of the intake valve 16, and the variable valve timing mechanism 37 is interlocked with the crankshaft 33. The cam shaft 90 rotating, the first cam 91 and the second cam 92 provided on the cam shaft 90 and having different cam profiles, and the first cam 91 abutting on the cam shaft 90 and swinging as the first cam 91 rotates. The first swing arm 50 that moves, the second swing arm 60 that abuts on the second cam 92 and swings according to the rotation of the second cam 92, and the first swing arm 50 are connected to the first swing arm 50. 50 and the intake valve 16, a first state in which the first swing arm 50 is swung according to the rotation of the first cam 91, and the second swing arm 6. With those comprising the second state and switchable switching means 100 to swing, the according to the rotation of the second cam 92.
With this configuration, the intake valve 16 can be opened and closed by the first cam 91 or the second cam 92 having different cam profiles, and the opening / closing timing of the intake valve 16 can be changed to the timing corresponding to each cam. . For example, as in this embodiment, the closing timing of the intake valve 16 is changed to one of the timing earlier than the intake bottom dead center B of the piston 31 or the vicinity of the intake bottom dead center B of the piston 31. Can do. In this case, the opening / closing timing of the intake valve 16 can be switched with a simple configuration, the number of parts and the number of assembly steps can be reduced, and the manufacturing cost can be reduced. Further, by reducing the number of parts and the number of assembly steps, it is possible to suppress the occurrence of dimensional errors and errors during assembly, and thus improve the reliability of the engine as a whole.

Further, the switching means 100 is attached to the first swing arm 50 and the receiving member 150 attached to the second swing arm 60, and comes into contact with the receiving member 150, whereby the first swing arm 50 is moved to the first cam 91. And a hydraulic piston 130 that can be moved integrally with the second swing arm 60.
With this configuration, the switching unit 100 can be configured easily. Therefore, it is possible to reduce the number of parts and assembly man-hours, and to reduce the manufacturing cost.

The switching means 100 operates the hydraulic piston 130 using lubricating oil supplied to each part of the engine.
By configuring in this way, it is possible to operate the switching mechanism using the lubricating oil of the engine 1, so there is no need to use a separate hydraulic pump or the like, and it is possible to reduce the number of parts and assembly man-hours, The manufacturing cost can be reduced.

The lubricating oil for operating the hydraulic piston 130 is a piston operating oil passage 50d formed in the first swing arm 50 and a first swing arm shaft 40 that swingably supports the first swing arm 50. The oil is supplied to the hydraulic piston 130 through one oil passage 40a.
With this configuration, there is no need to separately provide piping or the like for supplying lubricating oil for operating the hydraulic piston 130, and the number of parts and assembly man-hours can be reduced.
Here, if the supply structure of the lubricating oil to the hydraulic piston 130 is connected to the piston operating oil passage 50d formed in the first swing arm 50 from the outside of the first swing arm 50, lubrication is performed. When the oil is configured to be supplied to the hydraulic piston 130 through these pipes and the piston operating oil passage 50d, the pipes may be disconnected, deformed, or damaged by the swing of the first swing arm 50. There is. On the other hand, in order to cope with the swing of the first swing arm 50, when a flexible pipe or the like is connected to the piston operating oil passage 50d, the first swing arm 50 swings. Then, the pipe or the like moves and bends so as to follow the first swing arm 50, and the oil passage shape inside thereof is deformed. Therefore, there is a possibility that the lubricating oil cannot be stably supplied to the hydraulic piston 130. Further, there is a possibility that the piping and the like may be detached due to the swing of the first swing arm 50.
However, in the engine according to the present embodiment, the structure for supplying the lubricating oil to the hydraulic piston 130 has the first oil passage 40a formed in the swing arm shaft 40 that supports the first swing arm 50 so as to be swingable. Since the lubricating oil is connected to the operating oil passage 50d and is supplied to the hydraulic piston 130 through the first oil passage 40a and the piston operating oil passage 50d, the first swing arm 50 is swung. Even if it moves, the oil passage shape of the first oil passage 40a is held constant. In other words, the supply of the lubricating oil to the hydraulic piston 130 is not affected by the swing of the first swing arm 50. Therefore, the lubricating oil can be stably supplied to the hydraulic piston 130.

The first swing arm 50 includes a first cam roller 52 that is rotatably supported and is in contact with the first cam 91. The lubricating oil that lubricates the first cam roller 52 is an oil passage for piston operation. The first roller lubricating oil passage 50c formed in the first swing arm 50 separately from 50d and the second oil passage 40b formed in the swing arm shaft 40 separately from the first oil passage 40a It is supplied to the cam roller 52.
With this configuration, there is no need to separately provide piping or the like for supplying the lubricating oil for lubricating the first cam roller 52, and the number of parts and the number of assembly steps can be reduced. Further, the lubricating oil is supplied to the first cam roller 52 through an oil path different from that of the hydraulic piston 130. Therefore, when the structure for supplying the lubricating oil to the first cam roller 52 is configured to supply the lubricating oil to the first cam roller 52 via the same oil passage as that of the hydraulic piston 130, the lubricating oil is lubricated in the oil passage. Although the oil flow may be hindered depending on the operating state of the hydraulic piston 130, the risk is eliminated. Accordingly, the lubricating oil can be stably supplied to the first cam roller 52, and the first cam roller 52 can be reliably lubricated.

Further, a switching valve 140 for switching the operation of the hydraulic piston 130 is attached to the first swing arm 50.
With this configuration, it is possible to reduce the number of parts and the number of assembly steps. Further, the switching means can be configured compactly, and space saving can be achieved.

Further, at least one of the cam profile of the first cam 91 and the cam profile of the second cam 92 is set so that the intake valve 16 is closed at a time earlier than the intake bottom dead center B. It is.
With this configuration, by advancing the closing timing of the intake valve 16, the air can be adiabatically expanded in the cylinder 11a and the combustion temperature can be lowered. As a result, the amount of NOx generated can be reduced.

Further, the engine 1 with the supercharger 2 according to the present embodiment includes a variable valve timing mechanism 37 that changes the valve closing timing of the intake valve 16 and an overload that forcibly sends air into the cylinder 11a using exhaust energy. The variable valve timing mechanism 37 sets the closing timing of the intake valve 16 at a timing earlier than the intake bottom dead center B during high load operation, and performs low load operation. In some cases, the closing timing of the intake valve 16 is set later than that during high-load operation.
With this configuration, the turbocharger 2 can function sufficiently because the displacement is large during high load operation. In this case, the combustion temperature can be lowered by a so-called early closing type mirror cycle to reduce the amount of NOx generated. Further, since the exhaust amount is small during low load operation, the supercharger 2 does not function sufficiently, and if the intake valve 16 is closed at the same time as during high load operation, the amount of air pumped into the cylinder 11a In this case, the closing timing of the intake valve 16 is set later than in the case of high load operation, and is brought closer to the intake bottom dead center B after the intake process, so that the air enters the cylinder 11a. Can be inhaled sufficiently. Accordingly, it is possible to prevent deterioration of performance such as increase in generated black smoke and deterioration of acceleration and startability. Thus, by switching the valve closing timing of the intake valve 16 between the low load operation and the high load operation, it is possible to reduce the amount of NOx generated while preventing deterioration in performance.

The variable valve timing mechanism 37 sets the closing timing of the intake valve 16 in the vicinity of the intake bottom dead center B during low load operation.
With this configuration, it is possible to reliably suck a sufficient amount of air during low load operation. Accordingly, it is possible to prevent deterioration of performance such as increase in generated black smoke and deterioration of acceleration and startability.

The variable valve timing mechanism 37 includes a camshaft 90 that rotates in conjunction with the crankshaft 33, a first cam 91 and a second cam 92 that are provided on the camshaft 90 and have different cam profiles, and a first cam. A first swing arm 50 that is in contact with 91 and swings according to the rotation of the first cam 91; and a second swing arm 60 that is in contact with the second cam 92 and swings according to the rotation of the second cam 92; A push rod 70 connected to the first swing arm 50 to link the first swing arm 50 and the intake valve 16; and a first state in which the first swing arm 50 is swung according to the rotation of the first cam 91; Switching means 100 that can be switched to a second state in which the second swing arm 60 is swung in accordance with the rotation of the second cam 92, and the cam profile of the first cam 91 is provided. Based on the Le and the cam profile of the second cam 92, and sets the closing timing of the intake valve 16.
With this configuration, the intake valve 16 is opened / closed by the first cam 91 or the second cam 92 having different cam profiles, and the closing timing of the intake valve 16 is different between the high load operation and the high load operation. The timing can be changed as appropriate. As a result, the amount of NOx generated can be reduced during high-load operation, and the performance of the engine 1 can be prevented from deteriorating during low-load operation. Further, in this case, the opening / closing timing of the intake valve 16 can be switched with a simple configuration, the number of parts and the number of assembly steps can be reduced, and the manufacturing cost can be reduced.

  In the present embodiment, the cam profile of the first cam 91 is set so that the intake valve 16 is closed earlier than the intake bottom dead center B, but the present invention is not limited to this. Alternatively, the cam profile of the second cam 92 can be set so that the intake valve 16 is closed earlier than the intake bottom dead center B.

  In the present embodiment, the variable valve timing mechanism 37 realizes a so-called early closing type mirror cycle in the first state. However, the present invention is not limited to this, and the late closing type mirror cycle is implemented. The valve closing timing of the intake valve 16 can also be set arbitrarily by arbitrarily setting the cam profiles of the first cam 91 and the second cam 92.

  Further, the variable valve timing mechanism 37 is not limited to the configuration according to the present embodiment. For example, the mounting angle of the first cam 91 or the second cam 92 with respect to the cam shaft 90 can be changed by hydraulic pressure or the like. Etc. are also possible.

  Further, in the present embodiment, the control device 160 determines whether the engine 1 is in an operating state (i.e., operating at a high load or a low load) based on detection values of the fuel injection amount detecting means 161 and the engine speed detecting means 162. However, the present invention is not limited to this. For example, it is possible to detect the exhaust gas amount of the engine 1 and to determine the operating state of the engine 1 based on the exhaust gas amount.

DESCRIPTION OF SYMBOLS 1 Engine 2 Supercharger 3 Intercooler 4 Hydraulic pump 11a Cylinder 16 Intake valve 37 Variable valve timing mechanism 40 Swing arm shaft 50 First swing arm 60 Second swing arm 70 Push rod 80 Valve arm 90 Cam shaft 91 First cam 92 Second cam 100 switching means 160 control device

Claims (7)

An engine having a variable valve timing mechanism capable of changing the closing timing of the intake valve,
The variable valve timing mechanism is
A camshaft that rotates in conjunction with the crankshaft;
A first cam and a second cam provided on the cam shaft and having different cam profiles from each other;
A first swing arm that is in contact with the first cam and swings according to the rotation of the first cam;
A second swing arm that is in contact with the second cam and swings according to the rotation of the second cam;
A push rod connected to the first swing arm to link the first swing arm and the intake valve;
Switching means switchable between a first state in which the first swing arm is swung according to the rotation of the first cam and a second state in which the first swing arm is swung according to the rotation of the second cam together with the second swing arm;
An engine comprising: The switching means is
A receiving member attached to the second swing arm;
A hydraulic pressure attached to the first swing arm and contacting the receiving member to separate the first swing arm from the first cam and to operate integrally with the second swing arm. An actuator,
The engine according to claim 1, comprising:   The engine according to claim 2, wherein the switching unit operates the hydraulic actuator using lubricating oil supplied to each part of the engine. The lubricating oil that operates the hydraulic actuator is:
The hydraulic actuator is supplied to the hydraulic actuator through an oil passage for operating the hydraulic actuator formed in the first swing arm and a first oil passage formed in a swing arm shaft that swingably supports the first swing arm. The engine according to claim 2 or claim 3. The first swing arm is
A cam roller that is rotatably supported and is in contact with the first cam;
The lubricating oil for lubricating the cam roller is
Through the oil passage for roller lubrication formed in the first swing arm separately from the oil passage for operating the hydraulic actuator, and through the second oil passage formed in the swing arm shaft separately from the first oil passage, The engine according to claim 4, wherein the engine is supplied to the cam roller.   The engine according to any one of claims 2 to 5, wherein a switching valve for switching the operation of the hydraulic actuator is attached to the first swing arm.   The cam profile of at least one of the cam profile of the first cam or the cam profile of the second cam is set so that the intake valve is closed at a time earlier than the intake bottom dead center. The engine according to any one of Items 6 to 6.

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