JP2009085187A - Compression ratio variable engine - Google Patents

Compression ratio variable engine Download PDF

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Publication number
JP2009085187A
JP2009085187A JP2007259552A JP2007259552A JP2009085187A JP 2009085187 A JP2009085187 A JP 2009085187A JP 2007259552 A JP2007259552 A JP 2007259552A JP 2007259552 A JP2007259552 A JP 2007259552A JP 2009085187 A JP2009085187 A JP 2009085187A
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Japan
Prior art keywords
gear
compression ratio
engine
eccentric shaft
crankshaft
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Pending
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JP2007259552A
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Japanese (ja)
Inventor
Akira Tanaka
朗 田中
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Yamaha Motor Co Ltd
ヤマハ発動機株式会社
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Application filed by Yamaha Motor Co Ltd, ヤマハ発動機株式会社 filed Critical Yamaha Motor Co Ltd
Priority to JP2007259552A priority Critical patent/JP2009085187A/en
Publication of JP2009085187A publication Critical patent/JP2009085187A/en
Pending legal-status Critical Current

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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02BINTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00Other engines
    • F02B75/04Engines with variable distances between pistons at top dead-centre positions and cylinder heads
    • F02B75/048Engines with variable distances between pistons at top dead-centre positions and cylinder heads by means of a variable crank stroke length

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a compression ratio corresponding to a load of an engine while making an expansion ratio larger than the compression ratio, and to continuously change the compression ratio. <P>SOLUTION: This engine comprises an eccentric shaft 15 in parallel to a crank shaft 2, and a drive device 8 for rotating the eccentric shaft 15 at a half of a rotation speed of the crank shaft 2. The engine has a link 5 interposed between a crank pin 3 and a large end 4a of a connection rod 4, and a lever 7 connecting the link 5 with the eccentric shaft 15. The drive device 8 is provided with: a planetary gear decelerator 21, and a phase changing device 23 for changing a rotation phase of the eccentric shaft 15 by changing an actuating condition of the planetary gear decelerator 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable compression ratio engine configured to be able to change a compression ratio during operation.

  Conventionally, as an engine that can change the stroke in the expansion stroke with respect to the stroke in the compression stroke of the piston, there are those described in Patent Document 1 and Patent Document 2, for example. An engine disclosed in Patent Document 1 includes an eccentric shaft configured to be rotatable on an axis parallel to the crankshaft, and transmits the rotation of the crankshaft to the eccentric shaft so that the eccentric shaft is rotated at a rotational speed of the crankshaft. Of the drive shaft that rotates at a rotational speed of 1/2 of the above, a link interposed between the crank pin of the crankshaft and the large end of the connecting rod, and on the opposite side of the connecting rod across the crank pin in this link And a lever having one end rotatably connected and the other end rotatably connected to the eccentric shaft.

  According to this engine, when the crankshaft rotates once, the eccentric shaft rotates by 1/2 rotation, and the position of the piston changes corresponding to the rotation of the eccentric shaft. For example, during the period from the start of the compression stroke to the end of the expansion stroke (while the crankshaft rotates once from the position where the crank angle is 180 °), the eccentric shaft rotates by 1/2 rotation, thereby the lever When the end portion on the eccentric shaft side is separated from the crankshaft, the position of the top dead center is lowered and the position of the bottom dead center is lowered. In this case, since the expansion ratio is larger than the compression ratio, the thermal efficiency is increased, so that fuel efficiency and output can be improved.

  The engine drive device disclosed in Patent Document 1 employs a configuration in which the rotation of the crankshaft is reduced to 1/2 by a reduction gear including a gear, a chain, a belt, etc. and transmitted to the eccentric shaft. That is, the eccentric shaft rotates at a rotational speed ½ that of the crankshaft so that the rotational phase is constant with respect to the crankshaft.

  In this drive device, in order to set the rotation phase of the eccentric shaft with respect to the crankshaft so that the expansion ratio is larger than the compression ratio as described above, the position where the gears mesh with each other when the gear is used as a speed reducer. Is performed at a predetermined position. Further, when the speed reducer is configured using a chain or a belt, it is performed by positioning the chain or belt winding position with respect to the sprocket or pulley at a predetermined position.

The engine described in Patent Document 2 includes a drive device having a configuration different from that of the drive device described in Patent Document 1. The drive device disclosed in Patent Document 2 adopts an operation mode in which the expansion ratio is larger than the compression ratio as described above when the engine load is relatively large, and the engine load is relatively small. In this case, the operation mode is such that the compression ratio is relatively larger than the operation mode during the high load operation. These two modes of operation are switched by a dog clutch that operates in accordance with the magnitude of the negative pressure in the intake passage.
JP-A-9-228858 JP 2004-183644 A

  In the engine disclosed in Patent Document 1, when an operation mode in which the expansion ratio is larger than the compression ratio is adopted, the engine is operated at a constant compression ratio regardless of the magnitude of the engine load. For this reason, when this compression ratio is set to a value suitable for high load operation, combustion may become unstable during low load operation such as idling. On the other hand, if the compression ratio is set so that combustion is stabilized during low load operation, knocking may occur during high load operation, and output cannot be improved.

  In the engine disclosed in Patent Document 2, a low-load operation state (an operation state in which the compression ratio becomes high so that combustion is stabilized during low-speed operation) and a high-load operation state (the expansion ratio becomes larger than the compression ratio) The output changes suddenly when switching to the operation state in which the output can be obtained. For this reason, when this engine is mounted in, for example, an automobile, there is a problem that the passenger feels uncomfortable when the above-described switching is performed.

  The present invention has been made to solve such a problem, and a compression ratio corresponding to the engine load can be obtained and the compression ratio can be changed steplessly while adopting a configuration in which the expansion ratio is larger than the compression ratio. An object of the present invention is to provide a variable compression ratio engine.

  In order to achieve this object, a variable compression ratio engine according to the present invention transmits an eccentric shaft configured to be rotatable on an axis parallel to the crankshaft, and transmits the rotation of the crankshaft to the eccentric shaft. A drive device for rotating the eccentric shaft at a rotational speed that is half the rotational speed of the crankshaft, a link interposed between the crankpin of the crankshaft and the large end of the connecting rod, and a crankpin in this link In a variable compression ratio engine having a lever having one end rotatably connected to the opposite side of the connecting rod and the other end rotatably connected to the eccentric shaft, the drive unit includes the crankshaft. A speed reducer configured using a differential gear mechanism having an input member connected to the output shaft and an output member connected to the eccentric shaft, and changing the operating state of the differential gear mechanism Those which gave a phase changing device for changing the rotational phase of the mandrel.

  According to the present invention, the compression ratio is reduced by advancing the rotational phase of the eccentric shaft relative to the crankshaft in the invention, and a part of the combustion pressure is determined by the lever in the direction in which the eccentric shaft rotates. In this state, the eccentric shaft is urged by the rotational moment while being transmitted to the eccentric shaft via the.

  According to the present invention, in the invention, the reduction gear of the driving device is a planetary gear reduction gear, the input member is constituted by a sun gear of the planetary gear reduction gear, and the output member is constituted by an outer peripheral gear of the planetary gear reduction gear. And a member that serves as the fixed element is configured by a carrier that rotatably supports the planetary gear of the planetary gear reducer, and the phase change device includes a power source that is gear-coupled to the carrier, and a power source of the power source. And a control device that controls rotation.

  According to the present invention, in the invention, the speed reducer of the driving device is a planetary gear speed reducer, the input member is constituted by a sun gear of the planetary gear speed reducer, and the output member is an outer periphery of the planetary gear speed reducer. A connection state in which the member constituting the fixed element is constituted by a carrier that rotatably supports the planetary gear of the planetary gear speed reducer, and the phase change device is connected to the phase change device in which the rotation of the carrier with respect to the cylinder block is restricted. And a first clutch that switches between a disconnected state in which the restriction is released, a second clutch that switches between a connected state in which the carrier is connected to the outer peripheral gear and the eccentric shaft, and a disconnected state in which the connection is released. And a third clutch that switches between a connected state in which the eccentric shaft is braked and a disconnected state in which the braking is released. When the phase is maintained, only the first clutch is connected, only the second clutch is connected when the compression ratio is lowered, and only the third clutch is connected when the compression ratio is increased. Is.

  According to the present invention, in the above invention, the speed reducer of the drive device is positioned on the same axis as the differential case, a pinion that is rotatably supported by the differential case and revolves integrally with the differential case, and the differential case. A bevel gear differential device comprising a pair of side gears meshed with the pinion, wherein the input member is constituted by one side gear of the bevel gear differential device, and the output member is a differential of the bevel gear differential device A power source coupled to the other side gear, and a rotation of the power source. It is comprised with the control apparatus which controls.

  According to the present invention, in the above invention, a transmission member that transmits rotation of the crankshaft to an input member of the driving device is also connected to an input member of an engine accessory.

  According to the present invention, in the above invention, the transmission member that transmits the rotation of the crankshaft to the input member of the driving device is a gear formed by providing teeth on the outer periphery of a disc-shaped crank web. is there.

  The variable compression ratio engine according to the present invention can be configured such that the expansion ratio is larger than the compression ratio by a variable compression ratio mechanism including a link, a lever, an eccentric shaft, and a drive device. For this reason, in this engine, thermal efficiency can be increased, and fuel consumption and output can be improved.

  In this variable compression ratio engine, by changing the rotational phase of the eccentric shaft by the phase changing device, the position of the top dead center / bottom dead center of the piston and the reciprocating stroke of the piston change, and the compression ratio changes. For this reason, this engine can change a compression ratio, taking the driving | running form from which an expansion ratio becomes larger than a compression ratio and a thermal efficiency improves. An increase in the thermal efficiency of the engine means that the fuel efficiency of the engine is improved and the output is increased.

  The compression ratio of the engine is lowered by advancing the rotational phase of the eccentric shaft with respect to the crankshaft by the phase changing device, and conversely, it is increased by delaying the rotational phase of the eccentric shaft with respect to the crankshaft.

  Therefore, according to the present invention, the compression ratio can be made relatively high by delaying the rotational phase of the eccentric shaft by the phase change device when the engine load is relatively low. In other words, this engine can improve the fuel consumption by stabilizing the combustion during low-load operation while adopting an operation mode in which the expansion ratio is larger than the compression ratio and the thermal efficiency is improved. When the engine load is relatively high, the compression ratio can be made relatively low by advancing the rotational phase of the eccentric shaft by the phase changing device.

  In other words, this engine can be operated so as to increase thermal efficiency while preventing knocking during high load operation while adopting an operation mode in which the expansion ratio is larger than the compression ratio. Can be achieved. Since the phase changing device changes the position of a member that is a fixed element of the differential gear mechanism, the rotational phase of the eccentric shaft can be changed steplessly.

  Therefore, according to the present invention, there is provided a variable compression ratio engine capable of obtaining a compression ratio corresponding to the engine load and continuously changing the compression ratio while adopting a configuration in which the expansion ratio is larger than the compression ratio. be able to.

  In particular, by mounting the variable compression ratio engine according to the present invention on an automobile, even if the compression ratio changes due to a change in the engine load, it does not give the passenger a sense of incongruity, thus providing an automobile with good riding comfort. can do.

  According to the invention in which the rotation direction of the eccentric shaft is the direction in which the eccentric shaft to which a part of the combustion pressure is transmitted is urged by the rotation moment, the rotation phase of the eccentric shaft is phased when the engine load is relatively high. When the change device advances the crankshaft, the rotational phase of the eccentric shaft can be advanced with high responsiveness by using the combustion pressure of the engine.

  According to the invention in which the speed reducer of the drive device is constituted by a planetary gear speed reducer, the rotational phase of the eccentric shaft can be changed steplessly using the member for reducing the rotation of the crankshaft. Therefore, since two planetary gear speed reducers can be provided with the two functions of speed reduction and rotation phase change, compared to a case where a speed reducer that exclusively reduces and a device that exclusively changes the rotation phase are used in combination. The drive device can be made compact.

  According to the invention including the planetary gear speed reducer and the first to third clutches, one planetary gear speed reducer performs the function of reducing the rotation of the crankshaft and the function of changing the rotational phase of the eccentric shaft. be able to. Therefore, the drive device can be formed more compactly than when these functions are realized by different devices.

  Further, according to the present invention, when the second clutch is connected, the carrier is connected to the outer peripheral gear and the eccentric shaft that are rotating at a rotational speed that is 1/2 of the rotational speed of the crankshaft and moves. The carrier can be moved instantaneously (the rotational phase of the eccentric shaft can be changed). For this reason, according to the present invention, the rotational phase can be changed with high responsiveness compared to the case where the motor power is used to change the rotational phase of the eccentric shaft.

  According to the invention in which the speed reducer of the drive device is configured by a bevel gear differential, the rotational phase of the eccentric shaft can be changed steplessly using a member for decelerating the rotation of the crankshaft. Therefore, since two functions of speed reduction and rotation phase change can be given to a single bevel gear differential, compared to the case of using a device exclusively for speed reduction and a device for exclusively changing the rotation phase. The drive device can be made compact.

  According to the invention in which the transmission member for transmitting the rotation of the crankshaft to the drive device is also connected to the engine accessory, the gear, sprocket, pulley, etc. exclusively for driving the engine accessory is separated from the transmission member by the crankshaft. Compared with the case where it provides in, the axial direction length of a crankshaft can be formed short. Therefore, according to the present invention, the engine and the auxiliary device can be mounted on the engine while reducing the size of the engine without increasing the axial length of the crankshaft of the engine. As a result, the variable compression ratio engine according to the present invention can be accommodated in the engine room without enlarging the engine room of the automobile, despite having a variable compression mechanism including an eccentric shaft and a drive device. .

  According to the invention in which the driving gear is integrally formed on the crank web, when the gear for transmitting the rotation of the crankshaft to the input member of the driving device is formed separately from the crankshaft and provided on the crankshaft. In comparison, the length of the crankshaft in the axial direction can be shortened. For this reason, according to the present invention, the engine can be equipped with the drive device while reducing the size of the engine without increasing the length of the crankshaft of the engine in the axial direction. As a result, the variable compression ratio engine according to the present invention can be housed in the engine room without enlarging the engine room of the automobile, despite having a variable compression mechanism including an eccentric shaft and a drive device. .

  Further, according to the present invention, when the present invention is applied to a multi-cylinder engine, the drive device can be connected to an intermediate portion in the axial direction of the crankshaft. For this reason, compared with the case where the drive device is connected to one end of the crankshaft, the drive device does not protrude outward in the axial direction of the crankshaft from the engine, and a more compact compression ratio variable engine is provided. can do.

(First embodiment)
Hereinafter, an embodiment of a variable compression ratio engine according to the present invention will be described in detail with reference to FIGS.
FIG. 1 is a cross-sectional view showing a main part of a variable compression ratio engine according to the present invention, FIG. 2 is a longitudinal cross-sectional view showing the configuration of a drive device, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. In FIG. 3, the fracture position of FIG. 1 is indicated by the line I-I.

  4 is a longitudinal sectional view of the lower part of the cylinder block, FIG. 5 is a sectional view for explaining the direction in which the combustion pressure acts in the expansion stroke, and FIG. 6 is a sectional view showing changes in the crank angle and the phase angle of the control shaft. FIG. 4A shows the case of a crank angle 0 ° (720 °) at which the intake stroke is started, and FIG. 4B shows the case of a crank angle 180 ° at which the compression stroke is started. ) Shows a case where the crank angle is 360 ° at which the expansion stroke is started, and FIG. 4D shows a case where the crank angle is 540 ° at which the exhaust stroke is started.

  FIG. 7 is a sectional view for explaining the compression stroke of the piston. FIG. 7 (a) shows a state where the compression ratio is lowered, and FIG. 7 (b) shows a state where the compression ratio is increased. FIG. 8 is a graph showing the relationship between the crank angle and the change in piston height. FIG. 9 is a perspective view showing the configuration of the variable compression ratio engine, and FIG. 10 is a perspective view showing a state in which the drive unit portion of the variable compression ratio engine is removed. In FIG. 9, a link having a shape different from that of the embodiment is used. It is drawn in a state of being. FIG. 11 is a perspective view of the drive device, and FIG. 12 is a perspective view showing a planetary gear reducer of the drive device. FIG. 13 is a block diagram showing the configuration of the control device.

In these drawings, the reference numeral 1 indicates a variable compression ratio engine according to this embodiment.
This engine 1 is a four-cycle multi-cylinder engine for automobiles, and as shown in FIGS. 1 to 3, 9, and 10, between the crankpin 3 of the crankshaft 2 and the large end 4 a of the connecting rod 4. An interlinked link 5, a control shaft 6 configured to be rotatable on an axis parallel to the crankshaft 2, a lever 7 for connecting the control shaft 6 to the link 5, and the control shaft 6 A drive device 8 (see FIGS. 2, 3, 9 and 11) for rotating the crankshaft 2 at a rotational speed half that of the crankshaft 2 and changing the rotational phase relative to the crankshaft 2 is provided. In FIG. 1, reference numeral 9 denotes a cylinder block, 10 denotes a piston, and 11 denotes a piston pin. In addition, although the cylinder head, the valve operating apparatus, etc. which are provided in this engine 1 are not illustrated, those members well known in the art are used.

  As shown in FIG. 1, the crankshaft 2 of the engine 1 is positioned such that the center of rotation C is separated from the cylinder axis CL one side (one side where the control shaft 6 is located) when viewed from the axial direction. It has been. In this embodiment, the crankshaft 2 and the control shaft 6 rotate clockwise in FIG. Thus, when the crankshaft 2 rotates, the center of the crankpin 3 rotates along an imaginary circle indicated by a two-dot chain line A in FIG.

The link 5 includes a link body 5a that extends across the crankpin 3 in a direction perpendicular to the axial direction of the crankshaft 2, and a cap 5b that cooperates with the link body 5a to pinch the crankpin 3 rotatably. It is constituted by. The cap 5b is fixed to the link body 5a by two fixing bolts 5c.
A large end 4a of the connecting rod 4 is rotatably connected to one end of the link body 5a near the cylinder axis CL via a support shaft 12, and the other end of the link body 5a, that is, the link body 5a. One end portion of the lever 7 is rotatably connected via a support shaft 13 to an end portion extending to the opposite side of the connecting rod 4 with the crankpin 3 therebetween.

  As shown in FIG. 3, the control shaft 6 has a center shaft 14 rotatably supported by the cylinder block 9, and an eccentricity connected to the center shaft 14 so as to be eccentric by a predetermined amount via an arm portion 14a. The shaft 15 is formed so as to extend in parallel with the crankshaft 2 from one end portion to the other end portion of a plurality of cylinder rows. When the control shaft 6 rotates, the center of the eccentric shaft 15 rotates along an imaginary circle indicated by a two-dot chain line B in FIG. The control shaft 6 rotates in the same rotational direction as the crankshaft 2 at a rotational speed that is half the rotational speed of the crankshaft 2 when the rotation of the crankshaft 2 is transmitted via a drive device 8 described later. .

As shown in FIG. 10, the central shaft 14 is rotatable on a vertical wall 9a provided on the cylinder block 9 and a cap 9b attached to the vertical wall 9a by, for example, a slide bearing 16 (see FIG. 3). It is supported.
As shown in FIG. 3, the eccentric shaft 15 is aligned with the crankpin 3 of each cylinder when viewed from the axial direction of the cylinder. In other words, the eccentric shaft 15 is the same as the crankpin 3 of each cylinder in the axial direction of the control shaft 6. In the position.

  The other end of the lever 7 is rotatably connected to the eccentric shaft 15. As shown in FIG. 1, the lever 7 includes a lever main body 7a having one end connected to the link 5, and a cap 7b that cooperates with the lever main body 7a and rotatably holds the eccentric shaft 15. It is configured. The cap 7b is attached to the lever body 7a by a fixing bolt 7c.

  The position of the eccentric shaft 15 in the rotational direction with respect to the crankshaft 2 according to this embodiment, in other words, the rotational phase of the eccentric shaft 15 with respect to the crankshaft 2 is as shown in FIG. Is set to be. In FIG. 5, when the lever 7 is pulled upward, the link 5 rotates in the counterclockwise direction around the crankpin 3 in the figure, so that the connecting rod is connected despite the crankshaft 2 rotating clockwise. The large end portion 4a of the cylinder 4 descends at a position close to the cylinder axis CL. That is, the force with which the piston 10 pushes the connecting rod 4 obliquely in the expansion stroke is reduced. As a result, the loss caused by the piston 10 pushing the cylinder inner surface laterally is reduced, and the output is improved.

  As shown in FIG. 1, the specific rotational phase of the eccentric shaft 15 with respect to the crankshaft 2 is determined when the piston 10 is located at the compression top dead center (the crank angle is 360 °). A virtual straight line L1 extending in the direction opposite to the crankshaft 2 parallel to the cylinder axis CL from the axis of the central axis 14 as viewed from the axial direction, and from the axis of the central axis 14 through the axis of the eccentric shaft 15 The angle θ formed by the extending virtual straight line L2 (hereinafter, this angle θ is referred to as the rotation angle θ) is set to 210 °.

  Since the eccentric shaft 15 is rotated at a rotational speed that is half the rotational speed of the crankshaft 2 by the drive device 8 described later, the rotational angle θ when the piston 10 is located at the bottom dead center is The angle is 90 ° smaller or 90 ° larger than the rotation angle 210 ° when the piston 10 is located at the compression top dead center. That is, in the state where the piston 10 is located at the bottom dead center when shifting from the intake stroke to the compression stroke (the crank angle is 180 °), the eccentric shaft 15 is as shown in FIG. The rotation angle θ is located at a position where the rotation angle θ is 120 ° which is smaller than the 210 ° by 90 °.

In the state where the piston 10 is located at the bottom dead center where the expansion stroke is changed to the compression stroke (the crank angle is 540 °), the eccentric shaft 15 is The rotation angle θ is located at a position where the rotation angle θ is 300 ° which is 90 ° larger than the 210 °.
Further, in the state where the piston 10 is located at the top dead center where the exhaust stroke is shifted to the intake stroke (the crank angle is 0 ° or 720 °), the eccentric shaft 15 is shown in FIG. As shown, the rotation angle θ is positioned at 60 °. FIG. 6C shows the same state as FIG.

  By setting the rotational phase of the eccentric shaft 15 with respect to the crankshaft 2 as shown in FIGS. 1 and 6, from the start of the compression stroke to the end of the expansion stroke, that is, FIGS. During the time shown in d), the eccentric shaft 15 is mainly displaced upward (in a direction away from the crankshaft 2). At this time, if the crankshaft 2 is stopped, the lever 7 is pulled upward in FIG. 6 and the link 5 rotates counterclockwise, so that the connecting rod 4 is lowered and the piston 10 is moved downward. Displace. For this reason, the compression stroke of the piston 10 becomes relatively short, and the expansion stroke of the piston 10 becomes relatively long. As a result, by setting the rotational phase as shown in FIGS. 1 and 6, the expansion ratio becomes larger than the compression ratio.

  The engine 1 according to this embodiment is configured to change the rotational phase of the eccentric shaft 15 in accordance with the engine load by a driving device 8 described later. More specifically, in this embodiment, the rotational phase is advanced until the rotational angle θ of the eccentric shaft 15 is increased by 90 ° with respect to the rotational phase shown in FIGS. In the engine 1, when the rotational phase shown in FIGS. 1 and 6 is set (when the rotational phase is relatively delayed), the piston 10 is in the compression stroke shown in the solid line in FIG. Move from the dead center to the compression top dead center indicated by the two-dot chain line. In this case, the eccentric shaft 15 rotates 90 ° from the position where the rotation angle θ becomes 120 ° and rotates to the position where the rotation angle θ becomes 210 °.

  On the other hand, in this engine, when the rotational phase of the eccentric shaft 15 is advanced by 90 ° from the case where the rotational phase is relatively delayed (when the rotational phase is relatively advanced), the piston 10 is shown in FIG. b) Move from a bottom dead center indicated by a solid line to a compression top dead center indicated by a two-dot chain line. In this case, the eccentric shaft 15 rotates 90 ° from the position where the rotation angle θ becomes 210 ° and rotates to the position where the rotation angle θ becomes 300 °.

  As shown in FIGS. 7A and 7B, the compression stroke S1 when the rotational phase of the eccentric shaft 15 is relatively delayed is longer than the compression stroke S2 when the rotational phase is relatively advanced. Become. That is, when the rotational phase of the eccentric shaft 15 is delayed as shown in FIG. 7A, the rotational phase is advanced as shown in FIG. As the rotational phase advances so that the rotational angle θ of the eccentric shaft 15 increases by 90 °, the compression ratio decreases.

  In the engine 1 according to this embodiment, the compression ratio becomes maximum when the rotational phase of the eccentric shaft 15 is set as shown in FIG. 7A, and the rotational phase is shown in FIG. 7B. In such a state, the compression ratio is the lowest.

The position (height) of the piston 10 when the rotational phase of the eccentric shaft 15 is delayed most (when the compression ratio becomes maximum) and the rotational phase of the eccentric shaft 15 most advanced (when the compression ratio becomes minimum) The position (height) of the piston 10 changes as shown in FIG.
In FIG. 8, the change in the height of the piston 10 when the compression ratio becomes the highest is indicated by a solid line, and the change in the height of the piston 10 when the compression ratio becomes the lowest is indicated by a broken line.

  As is apparent from FIG. 8, the compression stroke S1 of the piston 10 in the high compression ratio state is longer than the compression stroke S2 of the piston 10 in the low compression ratio state. Further, as shown in FIG. 8, it can be seen that the expansion ratio is larger than the compression ratio in both the high compression ratio state and the low compression ratio state.

  As shown in FIG. 5, the rotational phase of the eccentric shaft 15 in the engine 1 is set in a direction in which the eccentric shaft 15 is urged by the lever 7 when the lever 7 is pressed by the combustion pressure in the expansion stroke. Yes. In FIG. 5, the combustion pressure acting on the piston 10 is indicated by an arrow F1, the force applied from the connecting rod 4 to the link 5 is indicated by an arrow F2, and the force applied from the link 5 to the crankpin 3 is indicated by an arrow F3. The force applied from 5 to the lever 7 is indicated by the arrow F4. An arrow R indicates the direction of rotation of the eccentric shaft 15.

  This rotational direction R is a direction in which the eccentric shaft 15 is urged by the rotational moment M in a state where a part of the combustion pressure F1 indicated by the arrow F4 in FIG. 5 is transmitted to the eccentric shaft 15 via the lever 7. is there. By setting the rotational direction R of the eccentric shaft 15 in this way, when the rotational phase of the eccentric shaft 15 is advanced by the drive device 8 described later, the rotational phase of the eccentric shaft 15 is responded using the combustion pressure of the engine 1. It can proceed well.

  The drive device 8 has a deceleration function for rotating the eccentric shaft 15 at a rotational speed that is 1/2 of the rotational speed of the crankshaft 2, and a phase changing function for advancing or delaying the rotational phase of the eccentric shaft 15 as described above. Have. In order to realize these two functions at the same time, the drive device 8 includes a planetary gear speed reducer provided at the shaft end of the control shaft 6 as shown in FIGS. 2, 9, 11 and 12. 21 and a phase change device 23 for driving a carrier 22 (see FIGS. 3 and 11) which is a fixed element of the planetary gear speed reducer 21. In this embodiment, the planetary gear speed reducer 21 constitutes a speed reducer using the differential gear mechanism referred to in the present invention.

  As shown in FIG. 3, the planetary gear reducer 21 is positioned on the radially outer side of the sun gear 26 having a control shaft gear 25 meshed with the crank gear 24 of the crankshaft 2. An outer peripheral gear 27 connected to the control shaft 6, four planetary gears 28 interposed between the outer peripheral gear 27 and the sun gear 26, and the carrier 22 that supports the planetary gear 28. It is configured.

  The planetary gear speed reducer 21 is configured to decelerate the rotation of the control shaft gear 25 meshed with the crank gear 24 and rotate the control shaft 6 at a rotational speed half that of the crankshaft 2. Yes. That is, the planetary gear speed reducer 21 includes the speed ratio of the meshing portion of the crank gear 24 and the control shaft gear 25, the speed ratio of the meshing portion of the sun gear 26 and the planetary gear 28, and the planetary gear 28. And the speed ratio of the meshing portion with the outer peripheral gear 28 is configured to be ½. As shown in FIG. 3, the planetary gear speed reducer 21 according to this embodiment is disposed outside the cylinder block 9 and in a chain chamber 30 in which a timing chain 29 is provided.

  The crank gear 24 is fixed to one end of the crankshaft 2 so as to rotate integrally with the crankshaft 2. As shown in FIG. 4, the crank gear 24 according to this embodiment is connected to a drive gear 32 of an oil pump 31 in addition to the control shaft gear 25. The oil pump 31 is constituted by a gear pump, and as the drive gear 32 rotates, the oil in the oil pan 33 is sucked and discharged to an engine oil supply passage (not shown).

  The oil pump 31 is attached to the lower end portion of the cylinder block 9 and is accommodated in the oil pan 33. In this embodiment, the crank gear 24 constitutes a transmission member according to the present invention, the oil pump 31 constitutes an engine accessory according to the present invention, and the drive gear 32 defines an input of the engine accessory according to the present invention. A member is configured.

As shown in FIG. 3, the control shaft gear 25 is coupled to an axial center of the control shaft gear 25 so that one end portion of the sun gear 26 rotates integrally, and the center of the control shaft 6 is connected via the sun gear 26. The shaft 14 is rotatably supported.
The sun gear 26 is formed in a cylindrical shape, and is rotatably supported by the central shaft 14 with the central shaft 14 of the control shaft 6 passing therethrough. The teeth of the sun gear 26 are provided at the end opposite to the one end to which the control shaft gear 25 is fixed. The sun gear 26 and the control shaft gear 25 constitute an input member in the present invention.

The planetary gear 28 meshes with the sun gear 26 and the outer peripheral gear 27 in a state of being rotatably supported by a carrier 22 described later.
The outer peripheral gear 27 is formed in an annular shape, and a disk-shaped transmission plate 34 is provided on one side of the outer peripheral gear 27 that is located on the opposite side of the control shaft gear 25. The outer peripheral gear 27 is connected to the control shaft 6 through the transmission plate 34.

  An outer peripheral portion of the transmission plate 34 is fixed to the outer peripheral gear 27, and an inner peripheral portion of the transmission plate 34 is fixed to the central shaft 14 of the control shaft 6. For this reason, the control shaft 6 rotates integrally with the outer peripheral gear 27. In this embodiment, the outer peripheral gear 27 constitutes an output member in the present invention.

  As shown in FIG. 3, the carrier 22 has four support shafts 35 that rotatably support the planetary gear 28, and an annular plate shape fixed to both ends of these support shafts 35 by welding, press-fitting, or the like. The first and second support plates 36 and 37 are configured. Of the first and second support plates 36 and 37, the first support plate 36 close to the control shaft gear 25 is a disc portion 36a provided with the support shaft 35, as shown in FIG. And a fan-shaped power transmission portion 36b projecting radially outward from the outer peripheral portion of the disc portion 36a. As shown in FIG. 3, the disk portion 36 a is rotatably supported by the cylindrical portion of the sun gear 26. A worm wheel 41 of a phase changing device 23 described later is attached to the power transmission unit 36b.

  In the planetary gear speed reducer 21 configured as described above, the rotation of the sun gear 26 is transmitted to the outer peripheral gear 27 via the planetary gear 28 in a state where the rotation of the carrier 22 is regulated by a phase changing device 23 described later. The outer peripheral gear 27 and the control shaft 6 rotate at a rotational speed that is half the rotational speed of the crankshaft 2.

  The phase changing device 23 rotates or advances the rotational phase of the outer peripheral gear 27 and the control shaft 6 by rotating the carrier 22 around the axis of the control shaft 6. The rotational phase advances when the carrier 22 rotates in the same direction as the outer peripheral gear 27, and is delayed when the carrier 22 rotates in the opposite direction.

  As shown in FIGS. 9 and 11, the phase changing device 23 includes the worm wheel 41 provided on the carrier 22, an actuator 43 having a worm 42 meshing with the worm wheel 41, and the rotation of the actuator 43. And a control device 44 (see FIG. 13) for controlling the above.

The worm wheel 41 is formed in an arc shape that constitutes a part of a ring, and as shown in FIG. 3, there is a gap between the outer peripheral gear 27 and the outer peripheral gear 27 in the radial direction. Is attached and fixed to the power transmission portion 36b of the carrier 22.
In this embodiment, the actuator 43 is constituted by a servo motor. The worm 42 is provided so as to rotate integrally with a rotation shaft 43a of the servo motor. Further, as shown in FIG. 2, the actuator 43 has an axis of the rotating shaft 43a orthogonal to the axis of the crankshaft 2 and the axis CL of the cylinder, and the worm 42 is positioned below the planetary gear reducer 21. It is attached to the cylinder block 9 as described above. The actuator 43 constitutes a power source in the present invention.

As shown in FIG. 13, the control device 44 includes a load detection unit 45, a phase angle detection unit 46, and a motor control unit 47.
The load detector 45 is connected to a throttle valve opening sensor 48 that detects the opening of a throttle valve (not shown). The load detection means 45 detects the magnitude of the load of the engine 1 using the throttle valve opening detected by the throttle valve opening sensor 48. For this reason, the load of the engine 1 detected by this load detection part 45 becomes so high that the opening degree of a throttle valve becomes large.

  The phase angle detector 46 detects the rotational phase of the eccentric shaft 15 with respect to the crank angle as a phase angle. Since the phase angle of the eccentric shaft 15 corresponds to the angle in the rotation direction of the carrier 22 (worm wheel 41), in this embodiment, the rotation of the worm 42 is performed using an encoder (not shown) provided in the actuator 43. The rotation angle of the worm wheel 41 is calculated as the phase angle of the eccentric shaft 15 from the rotation number. In detecting the phase angle of the eccentric shaft 15, in addition to using the encoder as described above, for example, the teeth of the worm wheel 41 may be detected by an electromagnetic pickup (not shown) or the like. It can be changed as appropriate.

  The motor control unit 47 includes, for example, a map (not shown) of the phase angle data corresponding to the load level of the engine 1, and the load level of the engine 1 detected by the load detection unit 45. The actuator 43 is rotated by feedback control with the corresponding phase angle as the target phase angle. That is, when the load of the engine 1 is constant, the motor control unit 47 keeps the actuator 43 stopped so that the current rotational phase of the eccentric shaft 15 does not change.

Further, when the load of the engine 1 is shifted from a low state to a high state, such as during acceleration, the motor control unit 47 determines that the actual phase angle detected by the phase angle detection unit 46 is the current phase angle. The actuator 43 is rotated to coincide with the target phase angle corresponding to the load of the engine 1 to advance the phase angle of the eccentric shaft 15. In this case, the actuator 43 rotates the carrier 22 in the same direction as the outer peripheral gear 27.
As the phase angle of the eccentric shaft 15 is thus advanced, the compression ratio of the engine 1 is lowered. The change in the phase angle changes steplessly when the carrier 22 is rotated steplessly by the actuator 43, and as a result, the compression ratio gradually decreases steplessly.

  Further, when the load of the engine 1 is shifted from a high state to a low state, for example, during deceleration, the motor control unit 47 determines that the actual phase angle detected by the phase angle detection unit 46 is that of the current engine 1. The actuator 43 is rotated so as to coincide with the target phase angle corresponding to the load, and the phase angle of the eccentric shaft 15 is retarded. In this case, the actuator 43 rotates the carrier 22 in the direction opposite to the outer peripheral gear 27.

As described above, the phase angle of the eccentric shaft 15 is retarded, so that the compression ratio of the engine 1 is increased. Also in this case, the phase angle can be changed steplessly, and the compression ratio of the engine 1 gradually increases steplessly.
That is, the compression ratio of the engine 1 is the highest compression ratio (compression ratio when the operation mode shown by the solid line in FIG. 8 is adopted) and the lowest compression ratio (when the operation mode shown by the wavy line in FIG. 8 is adopted). The compression ratio).

  The compression ratio variable engine 1 configured in this way is configured so that the expansion ratio is larger than the compression ratio by the compression ratio variable mechanism including the link 5, the lever 7, the eccentric shaft 15, the drive device 8, and the like. Thermal efficiency can be increased, and fuel consumption and output can be improved.

  In this variable compression ratio engine 1, by changing the rotational phase of the eccentric shaft 15 by the phase change device 23, the position of the top dead center / bottom dead center of the piston 10 and the reciprocating stroke of the piston 10 are changed. Changes. For this reason, this engine 1 can change a compression ratio, taking a larger expansion ratio than a compression ratio and improving thermal efficiency. By increasing the thermal efficiency of the engine 1, the fuel efficiency of the engine 1 is improved and the output is increased.

The compression ratio of the engine 1 is lowered by advancing the rotational phase of the eccentric shaft 15 with respect to the crankshaft 2 by the phase changing device 23, and conversely, the rotational phase of the eccentric shaft 15 is delayed with respect to the crankshaft 2. Will be higher.
Therefore, according to this embodiment, the compression ratio can be made relatively high by delaying the rotational phase of the eccentric shaft 15 by the phase changing device 23 when the load of the engine 1 is relatively low. That is, the engine 1 can increase the compression ratio so that combustion is stabilized during low-load operation and further improve fuel efficiency while adopting an operation mode in which the expansion ratio is larger than the compression ratio and thermal efficiency is improved. be able to.

  Further, when the load on the engine 1 is relatively high, the compression ratio can be relatively lowered by advancing the rotational phase of the eccentric shaft 15 by the phase changing device 23. In other words, the engine 1 can be operated so as to increase thermal efficiency while preventing knocking during high load operation while adopting an operation mode in which the expansion ratio is larger than the compression ratio, thereby further improving fuel efficiency and output. Can be planned.

Since the phase changing device 23 changes the position of the carrier 22 that is a fixed element of the planetary gear speed reducer 21, the rotational phase of the eccentric shaft 15 can be changed steplessly.
Therefore, according to this embodiment, a variable compression ratio engine capable of obtaining a compression ratio corresponding to the load of the engine 1 and changing the compression ratio steplessly while adopting a configuration in which the expansion ratio is larger than the compression ratio. Can be provided.

  Since the automobile equipped with the variable compression ratio engine 1 according to this embodiment can change the compression ratio steplessly as described above, even if the compression ratio changes as the load of the engine 1 changes, the passenger feels strange. It gives a good ride comfort.

  The rotational direction R of the eccentric shaft 15 according to this embodiment is set to a direction in which the eccentric shaft 15 to which a part of the combustion pressure is transmitted is urged by the rotational moment M. Therefore, according to this embodiment, when the rotational phase of the eccentric shaft 15 is advanced with respect to the crankshaft 2 by the phase changing device 23 when the load of the engine 1 is relatively high, the combustion pressure of the engine 1 is used. Thus, the rotational phase of the eccentric shaft 15 can be advanced with good responsiveness.

  In this embodiment, the rotational phase of the eccentric shaft 15 can be changed steplessly by moving the carrier 22 that is a constituent member of the planetary gear speed reducer 21 for decelerating the rotation of the crankshaft 2. For this reason, since one planetary gear speed reducer 21 can be provided with two functions of speed reduction and rotation phase change, when a speed reducer that exclusively reduces and a device that exclusively changes the rotation phase are used in combination. In comparison, the drive device 8 can be formed more compactly.

  In the variable compression ratio engine 1 according to this embodiment, the crank gear 24 that transmits the rotation of the crankshaft 2 to the drive device 8 is also connected to the drive gear 32 of the oil pump 31. For this reason, according to this embodiment, compared to the case where a gear, a sprocket, a pulley, or the like for driving the oil pump 31 is provided on the crankshaft 2 separately from the crank gear 24, the crankshaft 2 of the engine 1 is provided. The length in the axial direction can be shortened. Therefore, according to this embodiment, the drive device 8 and the oil pump 31 are connected to the engine 1 while reducing the size of the engine 1 without increasing the overall length of the engine 1 (length in the axial direction of the crankshaft 2). Can be equipped.

As a result, the variable compression ratio engine 1 according to this embodiment is housed in the engine room without enlarging the engine room of the automobile, even though the variable compression mechanism including the eccentric shaft 15 and the driving device 8 is provided. can do.
In this embodiment, a gear is used to transmit the rotation of the crankshaft 2 to the planetary gear reducer 21, but this power transmission portion may use other power transmission members such as a belt and a chain. it can. Even when a belt or a chain is used, the oil pump 31 can be driven by the belt or chain.

(Second embodiment)
The planetary gear speed reducer 21 can be configured as shown in FIGS.
FIG. 14 is a front view showing another embodiment of the planetary gear speed reducer, in which a part of the carrier is broken and the transmission plate and the worm wheel are removed. FIG. 15 is a cross-sectional view taken along the line XV-XV in FIG. 14, and this figure is drawn with all components assembled. In these drawings, members that are the same as or equivalent to those described with reference to FIGS. 1 to 13 are given the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

  The crank gear 24 shown in FIGS. 14 and 15 is fixed to the shaft end portion of the crankshaft 2 by fixing bolts 51. The planetary gear reducer 21 according to this embodiment is configured to be located on the opposite side of the cylinder block 9 with the control shaft gear 25 interposed therebetween. Therefore, the transmission plate 34 that connects the outer peripheral gear 27 of the planetary gear speed reducer 21 and the control shaft 6 is provided so as to be farthest from the cylinder block 9.

The transmission plate 34 according to this embodiment is formed in a disk shape made of a flat plate and is welded to the control shaft 6 and the outer peripheral gear 27. The control shaft 6 is welded to the axial center portion of the transmission plate 34 so as to penetrate therethrough. The outer peripheral gear 27 is welded with its shaft end face overlaid on the transmission plate 34.
In the planetary gear speed reducer 21, the worm wheel 41 of the driving device 8 is integrally formed on the first support plate 36 of the carrier 22.
Even if the planetary gear speed reducer 21 is configured in this way, the same effect as that of the first embodiment can be obtained.

(Third embodiment)
The drive device can be configured as shown in FIG.
FIG. 16 is a cross-sectional view showing another embodiment of the driving device. In the figure, the same or equivalent members as those described with reference to FIGS. 1 to 13 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

  The crank gear 24 shown in FIG. 16 is formed integrally with the crank web 61 of the crankshaft 2. This crankshaft 2 is for a four-cylinder engine. The crank web 61 constituting the crank gear 24 is located on the third cylinder side of the pair of crank webs 61, 61 for the fourth cylinder.

  The sun gear 26 of the planetary gear speed reducer 21 according to this embodiment is provided with a bearing portion 62 by forming a wide space between the teeth of the sun gear 26 and the control shaft gear 25. The bearing portion 62 is rotatably supported on the vertical wall 9 a of the cylinder block 9.

By forming the crank gear 24 integrally with the crank web 61 as shown in this embodiment, the crank gear 24 is formed separately from the crankshaft 2 as in the first embodiment, for example. Compared with the case where it provides in, the length of the axial direction of the crankshaft 2 can be formed short. For this reason, according to this embodiment, the engine 1 can be equipped with the driving device 8 while reducing the size of the engine 1 without increasing the length of the crankshaft 2 in the axial direction of the engine 1.
As a result, the variable compression ratio engine 1 according to this embodiment includes the variable compression ratio mechanism including the eccentric shaft 15 and the driving device 8, but the engine room of the automobile is not enlarged without being enlarged. Can be stored.

  Further, according to this embodiment, when the present invention is applied to a multi-cylinder engine, the drive device 8 can be connected to an intermediate portion in the axial direction of the crankshaft 2. For this reason, compared with the case where the driving device 8 is connected to one end portion of the crankshaft 2, the driving device 8 does not protrude outward in the axial direction of the crankshaft 2 from the engine 1, so that it is more compact. A variable compression ratio engine can be provided.

(Fourth embodiment)
The drive device can be configured as shown in FIG.
FIG. 17 is a perspective view showing the configuration of another embodiment of the drive device. FIG. 17A shows the state during steady running, FIG. 17B shows the state during acceleration, and FIG. Indicates the state during deceleration. In the figure, the same or equivalent members as those described with reference to FIGS. 1 to 13 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

  A driving device 8 shown in FIG. 17 includes a planetary gear reducer 21 having the same structure as the planetary gear reducer shown in the first embodiment, first to third clutches C1 to C3 and a control device (not shown). And a phase change device 23 consisting of The driving device 8 according to this embodiment does not include a motor for driving the carrier 22.

  The first clutch C <b> 1 is interposed between the carrier 22 of the planetary gear reducer 21 and the cylinder block 9. The first clutch C1 includes a connected state (indicated by a solid line in FIG. 17) in which the rotation of the carrier 22 with respect to the cylinder block 9 is restricted, and a disconnected state (indicated by a broken line in FIG. 17) in which the restriction is released. It is comprised so that it can switch.

  The second clutch C <b> 2 is interposed between the carrier 22 and the rotating body including the outer peripheral gear 27 of the planetary gear reducer 21 and the control shaft 6. The second clutch C2 has a connection state (shown by a solid line in FIG. 17) in which the carrier 22 is connected to the outer peripheral gear 27 and the control shaft 6, and a disconnected state (indicated by a broken line in FIG. 17). ) And can be switched.

  The third clutch C <b> 3 is interposed between the control shaft 6 and the cylinder block 9. The third clutch C3 can switch between a connected state (indicated by a solid line in FIG. 17) in which the eccentric shaft 15 is braked and a disconnected state (indicated by a broken line in FIG. 17) in which the braking is released. It is configured as follows. The third clutch C3 can also be configured by a brake. The first clutch C1 and the second clutch C2 can also be configured by brakes. The clutch here includes a clutch that can rotate relative to one rotation with a slight difference in rotation, and the brake includes a clutch that can switch between rotation and stop of a rotating body.

  These first to third clutches C1 to C3 are connected to a control device (not shown), and the connected state and the disconnected state are switched by the control device. The control device according to this embodiment is configured to detect the position of the carrier 22 in the rotation direction by a sensor such as an electromagnetic pickup, and to obtain the current phase angle of the eccentric shaft 15 based on the position of the carrier 22 in the rotation direction. ing.

  Further, similarly to the first embodiment, this control device uses the phase angle of the eccentric shaft 15 corresponding to the load of the engine 1 as the target phase angle, and the current phase angle of the eccentric shaft 15 is the target phase angle. The connected state and the disconnected state of the first to third clutches C1 to C3 are switched by feedback control so as to match.

This control device sets only the first clutch C1 in the connected state when the phase is fixed to keep the compression ratio of the engine 1 constant, and sets only the second clutch C2 in the connected state when reducing the compression ratio. When raising, only the third clutch C3 is brought into a connected state.
More specifically, when the load on the engine 1 is constant, the control device, as shown in FIG. 17A, prevents the current rotational phase of the eccentric shaft 15 from changing. C1 is set to the connected state, and the second and third clutches C2 and C3 are set to the disconnected state.
By this clutch operation, the rotation of the carrier 22 is restricted, and the rotation phase of the eccentric shaft 15 can be made constant.

  In addition, when the load of the engine 1 is shifted from a low state to a high state, the control device sets the second clutch C2 to the connected state as shown in FIG. The third clutches C1 and C3 are disengaged. By this clutch operation, the outer peripheral gear 27 is rotated by the planetary gear 28, and at the same time, the outer peripheral gear 27, the carrier 22, and the planetary gear 28 rotate together, and the planetary gear 28 rotates in the same direction as the outer peripheral gear 27. To move (revolve).

  For this reason, since the carrier 22 rotates integrally in the same direction as the outer peripheral gear 27, the rotational phase of the eccentric shaft 15 advances. The control device 44 always detects the position of the carrier 22 in the rotational direction, and the target phase angle of the actual eccentric shaft 15 obtained based on the position of the carrier 22 in the rotational direction corresponds to the current load of the engine 1. When advanced to the phase angle, the second clutch C2 is switched to a disconnected state and the first clutch C1 is switched to a connected state.

  That is, in this embodiment, when the load of the engine 1 is increasing, the carrier 22 is rotated in the same direction as the outer peripheral gear 27 by the power of the engine 1, so that the phase angle of the eccentric shaft 15 is increased. Advance until the angle corresponding to the angle is reached. As the phase angle of the eccentric shaft 15 is thus advanced, the compression ratio of the engine 1 is lowered. The change in the phase angle changes steplessly when the carrier 22 is rotated steplessly by the power of the engine 1, and as a result, the compression ratio gradually decreases steplessly.

  Furthermore, when the load of the engine 1 is shifted from a high state to a low state, for example, during deceleration, the control device places the third clutch C3 in the engaged state as shown in FIG. 17 (c). At the same time, the first and second clutches C1 and C2 are disengaged. By this clutch operation, the control shaft 6 is decelerated, and accordingly, the carrier 22 rotates in the direction opposite to the outer peripheral gear 27. At this time, when the control device 44 delays until the actual phase angle of the eccentric shaft 15 obtained based on the position of the carrier 22 in the rotational direction matches the target phase angle corresponding to the load of the engine 1, The clutch C3 is disengaged and the first clutch C1 is engaged.

  That is, in this embodiment, when the load of the engine 1 is decreasing, the phase of the eccentric shaft 15 is rotated by rotating the carrier 22 in the direction opposite to the outer peripheral gear 27 by the braking force of the third clutch C3. The angle is retarded until an angle corresponding to the magnitude of the load is reached. As described above, the phase angle of the eccentric shaft 15 is retarded, so that the compression ratio of the engine 1 is increased. The change in the phase angle changes steplessly as the carrier 22 is rotated steplessly by the braking force, and as a result, the compression ratio gradually increases steplessly.

According to the embodiment shown in FIG. 17, the function of decelerating the rotation of the crankshaft 2 and the function of changing the rotation phase of the eccentric shaft 15 can be performed by one planetary gear reducer 21. Therefore, the drive device 8 can be formed more compactly than when these functions are realized by different devices.
Further, according to this embodiment, when the second clutch C2 is connected, the carrier 22 is attached to the outer peripheral gear 27 and the eccentric shaft 15 that are rotating at a rotational speed that is 1/2 of the rotational speed of the crankshaft 2. Since it is connected and moves, the carrier 22 can be instantaneously moved (the rotational phase of the eccentric shaft 15 is advanced). For this reason, according to this embodiment, the rotational phase can be delayed with high responsiveness at the time of acceleration or the like as compared with the case where the motor power is used to change the rotational phase of the eccentric shaft 15.

(Fifth embodiment)
As shown in FIG. 18, a bevel gear differential device can be used for a speed reducer configured using a differential gear mechanism.
FIG. 18 is a sectional view showing another embodiment of the speed reducer. In the figure, the same or equivalent members as those described with reference to FIGS. 1 to 13 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

  In the embodiment shown in FIG. 18, the bevel gear differential device 71 is used to reduce the rotational speed of the crankshaft 2 to a half rotational speed and transmit it to the control shaft 6. As is well known in the art, the bevel gear differential device 71 includes a differential case 72 that rotates on an axis oriented in the left-right direction (a direction parallel to the axis of the crankshaft 2) in FIG. 18, and the differential case. A pair of pinions 74, 74 that are rotatably supported by a support shaft 73 and revolve integrally with the differential case 72, and a pair that are positioned on the same axis as the differential case 72 and mesh with the pinion 74. The first and second side gears 75 and 76, and a housing 77 that accommodates these members.

  The bevel gear differential device 71 is supported by the cover member 78 by fixing the housing 77 to the cover member 78 of the cylinder block 9 with the axis of the differential case 72 parallel to the axis of the crankshaft 2. ing. The bevel gear differential device 71 according to this embodiment is disposed at a position adjacent to a transmission pulley 79 provided at one end of the crankshaft 2.

  The first side gear 75 located on the cylinder block 9 side (the right side in FIG. 18) of the first and second side gears 75 and 76 is connected to the control shaft gear 25, and the control shaft gear 25 is connected to the first side gear 75. Are connected to the crank gear 24. The first side gear 75 constitutes the input member in the present invention.

  An output shaft 81 is rotatably inserted in the shaft center portion of the first and second side gears 75 and 76. The output shaft 81 is positioned on the same axis as the control shaft 6, and the central shaft 14 of the control shaft 6 is coupled to one end of the output shaft 81 so as to rotate integrally. The other end of the output shaft 81 is rotatably supported by the housing 77 by a bearing 82.

  Further, the support shaft 73 of the pinion 74 passes through the intermediate portion of the output shaft 81 so as to rotate integrally with the output shaft 81. That is, the control shaft 6 is connected to the differential case 72 so as to rotate integrally with the output shaft 81 and the support shaft 73. In this embodiment, the differential case 72 constitutes an output member in the present invention.

  In this bevel gear differential device 71, the second side gear 76 is fixed to the housing 77, whereby the rotational speed of the first side gear 75 is reduced to ½ and the differential case 72 (control shaft). 6) rotates. In this embodiment, the second side gear 76 constitutes a member serving as a fixing element in the present invention.

  The second side gear 76 is attached to a portion protruding out of the differential case 72 so that the worm wheel 41 rotates integrally. The worm wheel 41 is connected to an actuator 43 having the same structure as that of the phase changing device 23 shown in the first embodiment.

  The phase changing device 23 according to this embodiment changes the rotational phase of the eccentric shaft 15 by rotating the second side gear 76 by the actuator 43. That is, the rotation phase of the differential case 72 (control shaft 6) is advanced by turning the worm wheel 41 to one side by the actuator 43, and the rotation of the differential case 72 (control shaft 6) is turned by turning the worm wheel 41 to the other side. The phase is delayed.

  Similarly to the first embodiment, the control device (not shown) of the phase change device 23 according to this embodiment also uses the feedback control to make the actual phase angle of the eccentric shaft 15 coincide with the target phase angle corresponding to the load of the engine 1. Thus, the rotation of the actuator 43 is controlled. The actual phase angle of the eccentric shaft 15 is obtained by calculation based on the rotational angle of the worm wheel 41, or the difference in rotational speed between the differential case 72 and the control shaft gear 25 (or the crank gear 24 or the crankshaft 2) is used. Can be obtained by calculation.

According to this embodiment, the rotational phase of the eccentric shaft 15 is changed steplessly by rotating the second side gear 76 that is a constituent member of the bevel gear differential device 71 for decelerating the rotation of the crankshaft 2. be able to. Therefore, since two functions of deceleration and rotation phase change can be provided to one bevel gear differential device 71, when a reduction gear that exclusively reduces and a device that exclusively changes the rotation phase are used in combination. Compared to the above, the drive device 8 can be made compact.
In each of the above-described embodiments, the configuration in which the operation of the actuator 43 and the clutches C1 to C3 is controlled by feedback control has been shown. The method for controlling the operation can be changed as appropriate.

It is sectional drawing which shows the principal part of the compression ratio variable engine which concerns on this invention. It is a longitudinal cross-sectional view which shows the structure of a drive device. It is the III-III sectional view taken on the line in FIG. It is a longitudinal cross-sectional view of a cylinder block lower part. It is sectional drawing for demonstrating the direction which the combustion pressure acts in an expansion stroke. It is sectional drawing which shows the change of the crank angle and the phase angle of a control shaft. It is sectional drawing for demonstrating the compression stroke of a piston. It is a graph which shows the relationship between a crank angle and the change of piston height. It is a perspective view which shows the structure of a compression ratio variable engine. It is a perspective view which shows the state which removed the drive device part of the compression ratio variable engine. It is a perspective view of a drive device. It is a perspective view which shows the planetary gear speed reducer of a drive device. It is a block diagram which shows the structure of a control apparatus. It is a front view which shows the other Example of the planetary gear speed reducer. It is the XV-XV sectional view taken on the line in FIG. It is sectional drawing which shows the other Example of a drive device. It is a perspective view which shows the structure of the other Example of a drive device. It is sectional drawing which shows the other Example of a reduction gear.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Variable compression ratio engine, 2 ... Crankshaft, 3 ... Crankpin, 4 ... Connecting rod, 5 ... Link, 6 ... Control shaft, 7 ... Lever, 8 ... Drive device, 9 ... Cylinder block, 10 ... Piston, 15 ... Eccentric shaft, 21 ... Planetary gear reducer, 22 ... Carrier, 23 ... Phase change device, 24 ... Crank gear, 25 ... Control shaft gear, 26 ... Sun gear, 27 ... Outer gear, 28 ... Planetary gear, 41 ... Worm wheel 42 ... Worm, 43 ... Actuator, 44 ... Control device, 71 ... Bevel gear differential, 72 ... Differential case, 74 ... Pinion, 75 ... First side gear, 76 ... Second side gear, C1 ... First Clutch, C2 ... second clutch, C3 ... third clutch C3.

Claims (7)

  1. An eccentric shaft configured to be rotatable on an axis parallel to the crankshaft;
    A drive device that transmits the rotation of the crankshaft to the eccentric shaft, and rotates the eccentric shaft at a rotational speed that is half the rotational speed of the crankshaft;
    A link interposed between the crankpin of the crankshaft and the large end of the connecting rod;
    In a variable compression ratio engine comprising a lever having one end rotatably connected to the opposite side of the connecting rod across the crankpin in this link and the other end rotatably connected to the eccentric shaft,
    The drive device includes a reduction gear configured using a differential gear mechanism having an input member connected to the crankshaft and an output member connected to the eccentric shaft, and an operating state of the differential gear mechanism And a phase change device that changes the rotational phase of the eccentric shaft by changing the compression ratio.
  2.   2. The compression ratio variable engine according to claim 1, wherein the compression ratio is reduced by a rotation phase of the eccentric shaft being advanced with respect to the crankshaft, and a direction in which the eccentric shaft rotates is a part of a combustion pressure. A variable compression ratio engine characterized in that the eccentric shaft is biased by a rotational moment in a state where is transmitted to the eccentric shaft via the lever.
  3. The compression ratio variable engine according to claim 1, wherein the reduction gear of the driving device is a planetary gear reduction gear,
    The input member is constituted by a sun gear of the planetary gear reducer,
    The output member is constituted by an outer peripheral gear of the planetary gear reducer,
    The member to be the fixing element is constituted by a carrier that rotatably supports the planetary gear of the planetary gear reducer,
    The phase change device comprises a power source gear-coupled to the carrier and a control device that controls the rotation of the power source.
  4. The compression ratio variable engine according to claim 1, wherein the reduction gear of the driving device is a planetary gear reduction gear,
    The input member is constituted by a sun gear of the planetary gear reducer,
    The output member is constituted by an outer peripheral gear of the planetary gear reducer,
    The member to be the fixing element is constituted by a carrier that rotatably supports the planetary gear of the planetary gear reducer,
    The phase change device includes a first clutch that switches between a connected state in which rotation of the carrier with respect to the cylinder block is restricted and a disconnected state in which the restriction is released.
    A second clutch for switching between a connection state in which the carrier is connected to the outer peripheral gear and the eccentric shaft and a disconnected state in which the connection is released;
    A third clutch that switches between a connected state in which the eccentric shaft is braked and a disconnected state in which the braking is released;
    When the phase is fixed to keep the compression ratio constant, only the first clutch is engaged,
    When lowering the compression ratio, only the second clutch is engaged,
    A variable compression ratio engine characterized in that only the third clutch is engaged when the compression ratio is increased.
  5. 2. The variable compression ratio engine according to claim 1, wherein the speed reducer of the driving device includes a differential case, a pinion rotatably supported by the differential case and revolving integrally with the differential case, and the same shaft as the differential case. A bevel gear differential comprising a pair of side gears positioned on a line and meshing with the pinion;
    The input member is constituted by one side gear of the bevel gear differential,
    The output member is constituted by a differential case of the bevel gear differential,
    The member serving as the fixing element is constituted by the other side gear of the bevel gear differential,
    The phase change device comprises a power source gear-coupled to the other side gear and a control device that controls the rotation of the power source.
  6.   2. The variable compression ratio engine according to claim 1, wherein the transmission member for transmitting the rotation of the crankshaft to the input member of the driving device is also connected to the input member of the engine accessory. engine.
  7.   2. The variable compression ratio engine according to claim 1, wherein the transmission member that transmits the rotation of the crankshaft to the input member of the driving device is a gear formed by providing teeth on the outer periphery of the disc-shaped crank web. A compression ratio variable engine characterized by being.
JP2007259552A 2007-10-03 2007-10-03 Compression ratio variable engine Pending JP2009085187A (en)

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JP2009243462A (en) * 2008-03-31 2009-10-22 Hyundai Motor Co Ltd Variable compression ratio device
WO2012139607A1 (en) * 2011-04-15 2012-10-18 Daimler Ag Reciprocating internal combustion engine having an adjusting device for variably adjusting a compression ratio
WO2012139621A3 (en) * 2011-04-15 2012-12-13 Daimler Ag Actuating device for variably adjusting a compression ratio of an internal combustion engine
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US20170002733A1 (en) * 2015-07-03 2017-01-05 Board Of Regents, The University Of Texas System Combustion Engine Linkage Systems
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CN110388264A (en) * 2018-04-18 2019-10-29 通用汽车环球科技运作有限责任公司 Variable compression ratio of engines device
US10767571B2 (en) 2018-07-18 2020-09-08 Ford Global Technologies, Llc Methods and system for operating an engine

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CN110388264A (en) * 2018-04-18 2019-10-29 通用汽车环球科技运作有限责任公司 Variable compression ratio of engines device
US10767571B2 (en) 2018-07-18 2020-09-08 Ford Global Technologies, Llc Methods and system for operating an engine

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