JP5229063B2 - Reciprocating internal combustion engine - Google Patents

Description

  The present invention relates to a reciprocating internal combustion engine including a variable compression ratio mechanism and a variable valve mechanism.

  In Patent Document 1, in a reciprocating internal combustion engine, a variable compression ratio mechanism that makes the engine compression ratio variable by changing the piston top dead center position and the valve lift characteristics of the intake or exhaust valve can be made variable. When the variable valve mechanism is used in combination, it is described that the valve lift amount is controlled to be decreased when the engine compression ratio is high, for example, so that the piston and the valve do not interfere with each other. The variable compression ratio mechanism and the variable valve mechanism are driven by separate actuators, and each actuator is independently controlled according to the engine operating state. For this reason, for example, when there is an abnormality in the sensor that detects the control amount of the variable valve mechanism, the valve lift characteristics allow for a sufficient safety margin so as not to cause interference in the event of an abnormality or failure in the control system. In addition, it is necessary to set a control range of the engine compression ratio, and the control range is greatly limited, or a valve recess recessed in the piston crown surface needs to be increased.

  As a technique for reliably avoiding interference between the piston and the valve, in Patent Document 2, the variable valve mechanism and the variable compression ratio mechanism are mechanically connected by a link mechanism. This variable compression ratio mechanism changes the engine compression ratio by moving the crankcase and the cylinder head relative to each other in accordance with the rotational position of the camshaft driven by the actuator. The crankcase and the control rod of the variable valve mechanism are connected. In this case, there is no room for interference between the piston and the valve due to an abnormality in the control system, and interference can be reliably prevented.

JP 2001-263099 A JP 2008-75602 A

  However, as in Patent Document 2, the variable valve mechanism is mechanically connected to the variable compression ratio mechanism that makes the engine compression ratio variable by moving the crankcase and the cylinder head relative to each other, and the variable compression ratio mechanism In the case of controlling the variable valve mechanism according to the compression ratio changing operation amount, the mechanism itself becomes very large, and the load and power consumption of the actuator become very large.

  The present invention relates to a reciprocating system in which a variable compression ratio mechanism that can change an engine compression ratio by changing a piston top dead center position and a variable valve mechanism that varies a valve lift characteristic of an intake or exhaust valve. In an internal combustion engine, interference between a piston and a valve is reliably avoided.

  That is, in the present invention, the control shaft that is mechanically connected to the variable compression ratio mechanism and mechanically connected to the variable valve mechanism, and the rotational position of the control shaft is changed and held. An actuator, and the engine compression ratio changes and the valve lift characteristic changes as the rotational position of the control shaft changes.

  According to the present invention, the variable compression ratio mechanism that can change the engine compression ratio by changing the piston top dead center position and the variable valve mechanism that changes the valve lift characteristic of the intake or exhaust valve are used in combination. However, both are connected to a single control shaft, and both the engine compression ratio and the valve lift characteristic are changed according to the rotational position of the control shaft. However, the engine compression ratio and valve lift characteristics do not change individually, and there is no room for interference between the piston and the valve due to an abnormality in the control system. It can be avoided.

1 is a configuration diagram showing a schematic configuration of a reciprocating internal combustion engine according to a first embodiment of the present invention. The figure which shows the control link for compression ratios and the control link for valve operating of the said 1st Example. Explanatory drawing which shows the relationship between the valve position with respect to a control-shaft angle, and a piston top dead center position. The figure which shows the control link for compression ratios and the control link for valve operating which concerns on 2nd Example of this invention. The figure which shows the compression ratio side torque and valve operating side torque of the said 2nd Example. The figure which shows the control link for compression ratios and the control link for valve operating in the setting state of the highest compression ratio which concerns on 3rd Example of this invention. The figure which shows the compression ratio side torque and the valve operating side torque in the setting state of the maximum compression ratio of the said 3rd Example. The figure which shows the control link for compression ratios and the control link for valve operating in the setting state of the minimum compression ratio which concerns on the said 3rd Example. The figure which shows the compression ratio side torque and the valve operating side torque in the setting state of the minimum compression ratio which concerns on the said 3rd Example. The block diagram which shows schematic structure of the reciprocating type internal combustion engine which concerns on 4th Example of this invention. The figure which shows the control link for compression ratios and the control link for valve operating of the said 4th Example. The figure which shows the control axis from which a diameter and a center position differ by the eccentric shaft part for compression ratios and the eccentric shaft part for valve operating, and the figure which shows the control link attached to this control axis (B). The figure (A) which shows the control shaft with the same diameter and center position by the eccentric shaft part for compression ratios and the eccentric shaft part for valve operating which concerns on 5th Example of this invention, and the control link attached to this control shaft. Figure (B) shown.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a reciprocating internal combustion engine according to a first embodiment of the present invention. The reciprocating internal combustion engine includes a variable compression ratio mechanism 11 using a multi-link type piston-crank mechanism that varies the engine compression ratio by changing the top dead center position of the piston 1, and a valve of the intake valve 16. A variable valve mechanism 12 having variable lift characteristics is provided for each cylinder, mechanically connected to the plurality of variable compression ratio mechanisms 11, and mechanically connected to the plurality of variable valve mechanisms 12. One control shaft 13 and one actuator 14 that changes and holds the rotational position of the control shaft 13, that is, an electric motor, are provided. As the rotational position of the control shaft 13 changes, the engine compression ratio changes and the valve lift characteristic changes. The operation of the actuator 14 is controlled according to the engine operating state by a control unit (not shown).

  The variable compression ratio mechanism 11 uses a multi-link type piston-crank mechanism as described in the above-mentioned Patent Document 1 and the like. The variable compression ratio mechanism 11 includes a lower link 4 that is rotatably attached to a crankpin 7 of the crankshaft 6. The upper link 3 that connects one end of the lower link 4 and the piston 1, and the compression ratio control link 9 that connects the other end of the lower link 4 and the control shaft 13. The piston 1 is fitted in a cylinder 2A formed in the cylinder block 2 so as to be able to reciprocate. The piston 1 and the upper link 3 are connected to each other by a piston pin 1A so that they can rotate relative to each other. The upper link 3 and the lower link 4 are connected to each other by a first connecting pin 5 so that they can rotate relative to each other. 9 is connected to the second connecting pin 10 so as to be relatively rotatable.

  The control shaft 13 is rotatably supported by the cylinder block 2. The control shaft 13 is provided with a compression ratio eccentric shaft portion 15 as shown in FIG. The eccentric shaft portion for compression ratio 15 has a cylindrical shape fixed or integrally formed with the control shaft 13, and the center 15 </ b> A of the circular outer peripheral surface is eccentric with respect to the rotation center 13 </ b> A of the control shaft 13. . The upper end of the compression ratio control link 9 is rotatably attached to the compression ratio eccentric shaft portion 15.

  With such a configuration, when the rotational position of the control shaft 13 changes according to the engine operation state, the compression ratio eccentric shaft portion 15 moves with respect to the rotation center 13A of the control shaft 13, and the compression ratio control link 9 is moved. As a result, the motion constraint condition of the lower link 4 changes, and the piston stroke characteristics including the piston top dead center position change, whereby the engine compression ratio changes. Further, as shown in FIG. 1, the trajectory A of the first connecting pin 5 is a vertically long elliptical trajectory, as compared with a single link type piston-crank mechanism in which the piston pin and the crank pin are connected by a single link. , By making the piston stroke characteristics appropriate characteristics close to simple vibration, the thrust-anti-thrust load acting on the piston 1 is reduced, and the piston speed and piston acceleration near the compression top dead center are suppressed, and combustion Stabilization and high efficiency can be achieved.

  Next, the variable valve mechanism 12 is applied to the intake valve 16 side of the intake valve 16 and the exhaust valve 17 provided above the piston 1 in the present embodiment. Both the period) and the valve lift amount are made variable simultaneously and continuously. The exhaust valve 17 is a direct-acting fixed valve that does not change its valve lift characteristics, and is opened and closed by a fixed cam (not shown) provided on the exhaust camshaft 18. The exhaust camshaft 18 is disposed above the valve lifter 17A of the exhaust valve 17 and is rotationally driven by the crankshaft 6 via a sprocket or a chain (not shown).

  The variable valve mechanism 12 includes a drive eccentric shaft portion 22 provided eccentric to the drive shaft 21, a first valve link 23 having one end connected to the drive eccentric shaft portion 22 so as to be relatively rotatable, and one end. The second valve link 24 is connected to the other end of the first valve link 23 by a third connecting pin 25 so as to be relatively rotatable, and the other end of the second valve link 24 is connected to the other end by a fourth connecting pin 27. A swing cam 26 that is rotatably connected, one end of which is rotatably connected to the first valve operating link 23 by a fifth connecting pin 29, and the other end of which is rotatable to a valve operating eccentric shaft 30 of the control shaft 13. And a valve control link 28 attached to the valve.

  Like the exhaust camshaft 18, the drive shaft 21 has a direct acting layout disposed above the valve lifter of the intake valve 16, and is driven to rotate by the crankshaft 6 via a sprocket or chain (not shown). The The swing cam 26 is rotatably attached to the drive shaft 21 and has a cam nose 26A having an appropriate cam profile that pushes down the valve lifter 16A of the intake valve 16. The valve operating eccentric shaft portion 30 has a cylindrical shape fixed to or integrally formed with the control shaft 13 like the compression ratio eccentric shaft portion 15, and the center 30A of the circular outer peripheral surface is the control shaft. It is eccentric with respect to the 13 rotation centers 13A.

  With this configuration, when the drive shaft 21 rotates in conjunction with the rotation of the crankshaft 6, the swing cam 26 is predetermined via the drive eccentric shaft portion 22, the first valve link 23 and the second valve link 24. The intake valve 16 is opened and closed by reciprocating rotational movement, that is, swinging within the range. Further, when the rotational position of the control shaft 13 is changed by the actuator 14 in accordance with the engine operating state, the valve-operating eccentric shaft portion 30 moves with respect to the rotation center of the control shaft 13, via the valve-control link 28. Thus, the motion restraint condition of the first valve link 23 changes, the swing angle range of the swing cam 26 changes, and both the operating angle of the intake valve 16 and the valve lift amount are continuously expanded or reduced.

  [1] Thus, in this embodiment, the variable compression ratio mechanism 11 that can change the engine compression ratio by changing the piston top dead center position, and the variable valve mechanism that makes the valve lift characteristics of the intake valve 16 variable. 12, both 11 and 12 are mechanically connected to a common control shaft 13, and the rotational position of the control shaft 13 is changed by an actuator 14, whereby both the engine compression ratio and the valve lift characteristic are changed. Since the structure is changed, the engine compression ratio and the valve lift characteristic do not change individually even though the structure is relatively compact, and there is room for interference between the piston 1 and the intake valve 16 due to an abnormality in the control system. Therefore, interference between the piston 1 and the intake valve 16 can be reliably avoided.

  [2] FIG. 3 shows the valve position (valve lift amount) of the intake valve and the piston top dead center position with respect to the angle of the control shaft 13. In the figure, the piston top dead center position is represented by a distance from a predetermined piston reference position Y0 (see FIG. 1) closer to the bottom dead center than the piston top dead center position to the piston top dead center position. Further, the valve position is represented by the distance from the piston reference position Y0 at the time of maximum lift, and the valve position becomes lower as the valve lift amount increases.

  As shown in the figure, regardless of the rotational position of the control shaft 13, a substantially constant margin width ΔM is set between the valve position and the piston top dead center position. That is, by rotating the control shaft 13 in the clockwise direction (first rotation direction), the piston top dead center position is lowered, the engine compression ratio is lowered, the valve lift amount is increased, and the valve position is increased. On the other hand, by rotating the control shaft 13 counterclockwise (second rotational direction), the piston top dead center position is increased, the engine compression ratio is increased, and the valve lift is decreased. The valve position becomes higher.

  For example, on the low speed / low load side, high compression ratio and low valve lift settings are used to improve fuel efficiency by improving the thermal efficiency by increasing the compression ratio, while reducing the valve lift (small operating angle) and intake air. By restricting the amount, it is possible to suppress / eliminate the throttle loss as compared with the case where the intake air amount is reduced by the throttle provided in the intake passage. On the high speed / high load side, the low compression ratio and high valve lift settings are used to suppress and avoid knocking by reducing the compression ratio, while increasing the valve lift (large operating angle) to reduce the load. The amount of intake air that increases with the increase can be secured.

  In this way, regardless of the rotational position of the control shaft 13, by maintaining a substantially constant margin width ΔM between the valve position and the piston top dead center position, interference between the intake valve and the piston can be reliably avoided. On the other hand, it is possible to realize appropriate valve lift characteristics and engine compression ratio settings according to engine operating conditions.

  [3] Referring to FIG. 2, in the variable compression ratio mechanism 11, a very large combustion pressure acts downward on the piston 1, and this lowers the lower pressure via the upper link 3 due to this combustion pressure. The counterclockwise torque in FIG. 2 acts on the link 4, and an upward compression ratio side load Fvcr from the compression ratio control link 9 to the control shaft 13 acts on the center 15 </ b> A of the compression ratio eccentric shaft portion 15. On the other hand, in the variable valve mechanism 12, a valve reaction force due to the valve spring acts from the intake valve 16 side during valve lift, and the counterclockwise torque is exerted on the swing cam 26 due to this valve reaction force. The valve-side load Fvel in the upward direction from the valve-control link 28 to the control shaft 13 via the second valve-link 24 and the first valve-link 23 acts as the center of the valve-centered eccentric shaft 30. Acts on 30A.

  Thus, when both loads Fvcr and Fvel act in the same direction, that is, when the angle formed by both loads Fvcr and Fvel is less than 90 degrees, the eccentricity for compression ratio is sandwiched between the rotation center 13A of the control shaft 13. The center 15A of the shaft portion 15 and the center 30A of the valve operating eccentric shaft portion 30 are set to be located on different sides. That is, a direction from the rotation center 13A of the control shaft 13 toward the center 15A of the eccentric shaft portion 15 for compression ratio and a direction from the rotation center 13A of the control shaft 13 toward the center 30A of the valve shaft eccentric shaft portion 30 are formed. The angle is set to exceed 90 degrees. As a result, the compression ratio side torque Tvcr acting on the control shaft 13 from the variable compression ratio mechanism 11 and the valve side torque Tvel acting on the control shaft 13 from the variable valve mechanism 12 are opposite to each other. Can be offset each other. Therefore, the driving torque when driving the control shaft 13 by the actuator 14 and the holding torque for holding the control shaft 13 in a predetermined position are reduced, and the energy consumption (power consumption) of the actuator 14 is suppressed. The actuator 14 can be reduced in size and weight.

  [4] Structurally, the variable compression ratio mechanism 11 is provided on the control shaft 13, and has an eccentric shaft portion 15 for compression ratio whose outer circle is eccentric with respect to the rotation center 13A of the control shaft 13. The piston 1 is connected to the piston 1 by a link row including a compression ratio control link 9 rotatably connected to the compression ratio eccentric shaft portion 15. Similarly, the variable valve mechanism 12 is provided on the control shaft 13 and has a valve-operating eccentric shaft portion 30 whose outer circle is eccentric with respect to the rotation center 13 </ b> A of the control shaft 13. A link train including a valve-operating control link 28 rotatably connected to the portion 30 is connected to a swing cam 26 as a valve operating member that opens and closes the intake valve 16.

  Therefore, by rotating the control shaft 13, the valve lift characteristic by the variable valve mechanism 12 and the engine compression ratio by the variable compression ratio mechanism 11 are continuously changed via the eccentric shaft portions 15 and 30, respectively. In addition, by appropriately setting the eccentric direction and the eccentric amount of the individual eccentric shaft portions 15 and 30, as shown in the above [3] and the following [5] to [10], the control shaft 13 Torque and load acting on the actuator 15 can be reduced, and the actuator 15 can be made smaller and lighter and energy consumption can be reduced.

  [5] Generally, the compression ratio side load Fvcr acting mainly from the variable compression ratio mechanism 11 side by the combustion pressure mainly acts from the variable valve mechanism 12 side due to the valve reaction force. It is larger than the load Fvel. Therefore, in the second embodiment shown in FIGS. 4 and 5, the eccentric amount ΔHvel of the valve operating eccentric shaft portion 30 with respect to the rotation center 13A of the control shaft 13 is set to the eccentric shaft for compression ratio with respect to the rotation center 13A of the control shaft 13. The eccentric amount ΔHvcr of the portion 15 is made larger. Here, the “eccentric amount” is a distance from the rotation center 13A of the control shaft to the centers 15A and 30A of the eccentric shaft portions. Thus, by relatively increasing the eccentric amount ΔHvel of the valve operating eccentric shaft portion 30, the length of the torque arm of the valve operating side torque with a small load can be increased, and thereby the valve operating side torque Tvel. And the compression ratio side torque Tvcr can be reduced, and the torque acting on the control shaft 13 can be more effectively offset and reduced.

  [6] FIGS. 6 and 7 show a third embodiment. In the setting state of the maximum compression ratio / minimum operating angle used in the low speed / low load range, that is, in the state where the control shaft 13 is rotated to the highest compression ratio / small operating angle side, the center of the eccentric shaft portion for the valve operating An angle formed by a link center line 28A of the valve control link 28 connecting 30A and the center of the fifth connecting pin 29, and a line connecting the rotation center 13A of the control shaft and the center 30A of the eccentric shaft portion of the valve θvel connects the link center line 9A of the compression ratio control link 9 that connects the compression ratio eccentric shaft portion 15A and the connecting pin 10, and the center 15A of the compression ratio eccentric shaft portion and the rotation center 13A of the control shaft 13. The angle θvcr formed by the line is set to be close to 90 degrees.

  Since the ratio of the actual torque arm length to the eccentric amount is the largest when the above angles θvel and vcr are 90 degrees, the angle on the valve operating side is larger than the angle θvcr on the compression ratio side. By making θvel close to 90 degrees, the substantial torque arm length is lengthened and the valve-side torque Tvel having a small valve-side load Fvel is increased, thereby reducing the difference between the two torques Tvel and Tvcr. Is possible. Therefore, the holding torque of the control shaft 13 is reduced and the maximum compression ratio / minimum operating angle is maintained in the setting state of the maximum compression ratio / minimum operating angle that is frequently used such as idle, low speed, and low load range. By reducing the torque, it is possible to reduce the power consumption of the actuator 14 and improve the fuel consumption.

  In particular, as shown in FIG. 7, the compression ratio side torque Tvcr due to the large compression ratio side load Fvcr is greatly increased by setting the angle θvcr on the compression ratio side to the vicinity of 0 degree or 180 degrees (for example, ± 10 degrees). It becomes possible to reduce it.

  [7] Similarly, in the setting state of the minimum compression ratio / maximum operating angle used in the high speed / high load range, that is, in the state where the control shaft 13 is rotated to the lowest compression ratio / large operating angle side, FIG. As shown in FIG. 9, the link center line 28A of the valve control link 28 connecting the center 15A of the valve operating eccentric shaft part and the center of the connecting pin 10, the rotation center 13A of the control shaft and the valve operating eccentric shaft part. The angle θvel formed by the line connecting the center 30A of the shaft and the link center line 9A of the compression ratio control link 9 connecting the eccentric shaft portion 30A for compression ratio and the fifth connecting pin 29 and the eccentric shaft portion for compression ratio. Is set so as to be closer to 90 degrees than an angle θvcr formed by a line connecting the center 30A and the rotation center 13A of the control shaft. As a result, even when the minimum compression ratio and maximum operating angle are set in a high speed / high load range where the combustion pressure is the highest, the substantial torque arm length on the valve side with a small load is the same as [6] above. By increasing the valve-side torque Tvel having a small load Fvel, the difference between the two torques Tvel and Tvcr acting on the control shaft 13 can be reduced, and the holding torque of the control shaft 13 can be reduced. .

  [8] In the fourth embodiment shown in FIGS. 10 and 11, the valve operating load Fvel acting on the control shaft 13 from the variable valve mechanism 12 side by the valve reaction force and the variable compression ratio mechanism 11 side by the combustion pressure. The compression ratio side load Fvcr acting on the control shaft 13 is set so as to act in opposite directions. That is, the angle between both loads Fvcr and Fvel is set to exceed 90 degrees. Thereby, both loads Fvel and Fvcr can be canceled each other, the bias of the load acting on the control shaft 13 and the stress concentration can be suppressed / relieved, and the friction at the time of driving the control shaft can be reduced. The bearing width of the control shaft can be reduced.

  Specifically, the swing direction of the swing cam 26 is reversed with respect to the first embodiment shown in FIG. Thus, in the variable valve mechanism 12, a valve reaction force due to the valve spring acts from the intake valve 16 side at the time of valve lift, and due to this valve reaction force, the swing cam 26 is rotated in the clockwise direction. Torque acts, and a downward load Fvel is applied from the valve control link 28 to the control shaft 13 via the second valve link 24 and the first valve link 23 to the center 30A of the valve eccentric shaft 30. Will act. On the other hand, in the variable compression ratio mechanism 11, as in the first embodiment, the combustion pressure acts downward on the piston 1, and due to this combustion pressure, the lower link 4 is counterclockwise via the upper link 3. Thus, an upward load Fvcr from the compression ratio control link 9 to the control shaft 13 acts on the center 15A of the compression ratio eccentric shaft portion 15. Therefore, the directions of the loads Fvcr and Fvel are opposite to each other.

  When both loads Fvcr and Fvel act in opposite directions as in the second embodiment, the center 15A of the eccentric shaft portion 15 for the compression ratio and the valve operating valve 15 The center 30A of the eccentric shaft part 30 is arranged in the same direction. That is, the angle formed by the direction from the rotation center 13A of the control shaft 13 toward the center 15A of the eccentric shaft portion 15 for compression ratio and the direction from the rotation center 13A of the control shaft 13 toward the center 30A of the eccentric shaft portion 30 for valve actuation. Is less than 90 degrees. Thus, as in the first embodiment, the compression ratio side torque Tvcr acting on the control shaft 13 from the variable compression ratio mechanism 11 and the valve side torque Tvel acting on the control shaft 13 from the variable valve mechanism 12 are obtained. They can act in opposite directions to cancel each other.

  [9] Referring to FIG. 12, in addition to the journal portion 31 rotatably supported by the cylinder block 2, the control shaft 13 and the plurality of compression ratio eccentric shaft portions 15 correspond to the plurality of cylinders. A valve eccentric shaft portion 30 is provided. For this reason, when the eccentric amounts and diameters of both 15 and 30 are different, the compression ratio control link 9 fitted to one control link, in this example, the compression ratio eccentric shaft portion 15 having a small diameter, is connected to the shaft of the control shaft 13. Cannot be inserted from one end of the direction. Therefore, for example, as shown in FIG. 12B, the control link 9 is divided into two divided bodies 32 and 33 along the diameter of the bearing hole 35 into which the eccentric shaft portion 15 is fitted, and the eccentric shaft portion is divided. 15, both the divided bodies 32 and 33 need to be fastened by bolts 34, which increases the number of assembling steps and increases the number of parts, the size, and the weight.

  Therefore, in the fifth embodiment shown in FIG. 13, the diameters of the valve operating eccentric shaft portion 30 and the compression ratio eccentric shaft portion 15 are the same. Thus, both the valve control link 28 attached to the valve eccentric shaft 30 and the compression ratio control link 9 attached to the compression ratio eccentric shaft 15 are inserted from one axial end of the control shaft 13. Can be assembled. Therefore, as shown in FIG. 13 (B), both control links 9 and 28 have a simple shape in which a bearing hole 35 into which the eccentric shaft portions 15 and 30 are rotatably fitted is integrally formed. As a result, the number of assembling steps can be reduced and the number of parts can be reduced, the size can be reduced, and the weight can be reduced as compared with the case of the divided structure shown in FIG.

  [10] In addition, in the fifth embodiment, the center 15A of the compression ratio eccentric shaft portion 15 and the center 30A of the valve operating eccentric shaft portion 30 are set on the same line parallel to the control shaft 13. . That is, when the control shaft 13 is viewed in the axial direction, the centers 15A and 30A of both eccentric shaft portions are set at the same position. As a result, when the control links 9 and 28 are inserted from one end side in the axial direction of the control shaft 13, it is not necessary to move in the radial direction each time the other eccentric shaft portions 15 and 30 are moved over. It will be easy. Further, if the centers of the eccentric shaft portions 15 and 30 are set at different positions, the other eccentric shaft portions 15 and 30 can be overcome when the control links 9 and 28 are inserted into the control shaft 13. Thus, although the distance between the adjacent eccentric shaft portions must be at least equal to or greater than the width of each eccentric shaft portion, the center 15A of both eccentric shaft portions when viewed in the axial direction of the control shaft 13 as in this embodiment. , 30A are set at the same position, the adjacent eccentric shaft portion 15 for compression ratio and the eccentric shaft portion 30 for valve train can be arranged sufficiently close to each other, and the axial dimension can be shortened and made compact. Can be achieved.

  [11] As shown in FIG. 1 and FIG. 10, the control shaft 13 is disposed above the crankshaft 6 and below the drive shaft 21 disposed above the intake valve 16. ing. By arranging the control shaft 13 between the crankshaft 6 and the drive shaft 21 in this way, each link component of the variable compression ratio mechanism 11 and the variable valve mechanism 12 connected to the control shaft 13 is located below the crankshaft 6. In addition, it is possible to suppress a large overhang of the drive shaft 21, to suppress an increase in the overall height of the engine, and to suppress the link length of the control links 9 and 28 connected to the control shaft 13. Thus, the variable compression ratio mechanism 11 and the variable valve mechanism 12 can be reduced in size and weight as a whole.

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes without departing from the spirit of the present invention. . For example, in the above embodiment, the variable valve mechanism is applied to the intake valve side, but the present invention can be similarly applied to the case where the variable valve mechanism is applied to the exhaust valve side.

DESCRIPTION OF SYMBOLS 1 ... Piston 2 ... Cylinder block 9 ... Compression ratio control link 11 ... Variable compression ratio mechanism 12 ... Variable valve mechanism 13 ... Control shaft 14 ... Actuator 15 ... Compression ratio eccentric shaft 16 ... Intake valve 17 ... Exhaust valve 28 ... Valve eccentric shaft 30 ... Valve control link

Claims (11)

A variable compression ratio mechanism that makes the engine compression ratio variable by changing the piston top dead center position;
A variable valve mechanism that varies the valve lift characteristics of the intake or exhaust valves;
A control shaft mechanically coupled to the variable compression ratio mechanism and mechanically coupled to the variable valve mechanism;
An actuator for changing and holding the rotational position of the control shaft,
A reciprocating internal combustion engine configured to change the engine compression ratio and the valve lift characteristics in accordance with a change in the rotational position of the control shaft. The variable valve mechanism makes the valve lift amount of the intake or exhaust valve variable,
By rotating the control shaft in the first rotational direction, the engine compression ratio is lowered, the valve lift amount is increased, and by rotating the control shaft in the second rotational direction, The reciprocating internal combustion engine according to claim 1, wherein the engine compression ratio increases and the valve lift amount decreases.   The compression ratio side torque that acts on the control shaft from the variable compression ratio mechanism due to the combustion pressure and the valve side torque that acts on the control shaft from the variable valve mechanism due to the valve reaction force The reciprocating internal combustion engine according to claim 1, wherein the reciprocating internal combustion engine is set to be in a reverse direction. The variable compression ratio mechanism is provided on the control shaft and has an eccentric shaft portion for compression ratio whose outer circle is eccentric with respect to the rotation center of the control shaft, and is rotatably connected to the eccentric shaft portion for compression ratio. Is connected to the piston by a link row including a compression ratio control link,
The variable valve mechanism is provided on the control shaft, and has an eccentric shaft portion for valve operation whose outer circle is eccentric with respect to the rotation center of the control shaft, and is rotatably connected to the eccentric shaft portion for valve operation. The reciprocating internal combustion engine according to any one of claims 1 to 3, wherein the reciprocating internal combustion engine is connected to a valve operating member that opens and closes the valve by a link train including the valve control link.   In the setting state of the maximum compression ratio, the angle formed by the line connecting the center of the eccentric valve shaft and the center of rotation of the control shaft and the link center line of the valve control link is the compression ratio. 5. The reciprocating system according to claim 4, wherein an angle formed between a line connecting the center of the eccentric shaft portion and the rotation center of the control shaft and a link center line of the compression ratio control link is closer to 90 degrees. Internal combustion engine.   In the state where the minimum compression ratio is set, the angle formed by the line connecting the center of the eccentric valve shaft and the rotation center of the control shaft and the link center line of the valve control link is the compression ratio. 6. The method according to claim 4, wherein an angle formed by a line connecting a center of the eccentric shaft portion and a rotation center of the control shaft and a link center line of the compression ratio control link is closer to 90 degrees. Reciprocating internal combustion engine.   7. The eccentricity of the eccentric shaft portion for valve operating with respect to the rotation center of the control shaft is larger than the eccentric amount of the eccentric shaft portion for compression ratio with respect to the rotation center of the control shaft. A reciprocating internal combustion engine according to claim 1.   The reciprocating internal combustion engine according to any one of claims 4 to 6, wherein a diameter of the eccentric shaft portion for valve operation and the eccentric shaft portion for compression ratio are the same.   9. The variable compression ratio internal combustion engine according to claim 8, wherein the center of the valve shaft eccentric shaft portion and the center of the compression ratio eccentric shaft portion are set at the same position as viewed in the axial direction.   A compression ratio side load acting on the control shaft from the variable compression ratio mechanism side due to combustion pressure; and a valve side load acting on the control shaft from the variable valve mechanism side due to the valve reaction force; The reciprocating internal combustion engine according to claim 1, wherein the reciprocating internal combustion engines are set so as to be in opposite directions.   The reciprocating device according to claim 1, wherein the control shaft is disposed above the crankshaft and below a drive shaft disposed above the valve. Internal combustion engine.

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