JP2018173073A - Variable compression ratio mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable compression ratio mechanism that can vary in compression ratio and expansion ratio, and also has high durability.SOLUTION: A variable compression ratio mechanism comprises: a plurality of cylinders 2; a plurality of pistons 3 inserted into the plurality of cylinders 2 respectively; a plurality of connecting rods 4 connected to the plurality of pistons 3 respectively to swing; a master connecting rod to which the plurality of connecting rods 4 are connected respectively to swing; a compression ratio changing member 53 which extends from the master connecting rod and is supported to swing and move vertically to enable the master connecting rod to rotate while swinging around a crank journal; and a support position changing mechanism which can change a support position of the compression ratio changing member 53 to a position moved horizontally.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an engine variable compression ratio mechanism.

  Conventionally, in a star engine, a variable displacement compression engine is known in which the strokes of two pistons are different and the compression ratio is variable (see, for example, Patent Document 1).

JP-T 2009-504976

  However, in the above technique, the variable compression ratio and the variable capacity function are linked (a large displacement is obtained when the large combustion chamber is changed, and a small displacement is obtained when the small combustion chamber is changed). Therefore, the expansion ratio is not changed, and it cannot be said that the gas pressure can be effectively used.

  Further, the above technique has problems in various points such as durability of the crankshaft itself and durability of a surface sliding with the crankshaft by rotating the crankshaft radially.

  The present invention has been made in view of the above, and an object thereof is to provide a variable compression ratio mechanism that can change the compression ratio and the expansion ratio and has high durability.

  In order to achieve the above object, the present invention provides a plurality of cylinders (for example, cylinder 2 described later), a plurality of pistons (for example, piston 3 described later) inserted into the plurality of cylinders, and the plurality of pistons. A plurality of connecting rods (for example, a connecting rod 4 described later), a master connecting rod (for example, a master connecting rod 5 described later) connected to each of the plurality of connecting rods, and the master. In order to enable the connecting rod to rotate while swinging about a predetermined point (for example, a distal end 53a described later), the connecting rod can swing and move in a first direction (for example, a vertical direction described later). The compression ratio changing member (for example, a compression ratio changing member 53 described later) supported by the crossing and the support position of the compression ratio changing member intersect the first direction. Two directions (e.g., left-right direction will be described later) can change the support position changing mechanism to a position moved (e.g., support position changing mechanism 8 to be described later) to provide a variable compression ratio mechanism having a.

  As a result, not only the compression ratio but also the expansion ratio can be changed. For example, when combustion is performed at an optimal compression ratio of 12, the expansion ratio after combustion becomes 12 or more, so that the gas pressure can be effectively used and converted into more power.

  The plurality of cylinders are connected to the master connecting rod via each connecting rod, and only the master connecting rod needs to be connected to the crankshaft, so that the crankshaft can be shortened. As a result, it is possible to simultaneously realize weight reduction, compactness, low friction, and high rigidity in the crank mechanism.

  The support position changing mechanism is a lever that is swingably connected to the compression ratio changing member.

  Thereby, it becomes possible to move the support position of the compression ratio changing member with a simple configuration.

  The at least two pistons and cylinders connected to the master connecting rod are arranged on the same plane.

  Thereby, since a some cylinder and piston can be divided into a some group, even if it mounts in a passenger car etc. with a big cabin, the erosion to a cabin decreases.

  According to the present invention, there is provided a variable compression ratio mechanism that can change the compression ratio and the expansion ratio and has high durability.

1 is a schematic front view showing a variable compression ratio mechanism 1 according to a first embodiment of the present invention. 1 is a schematic plan view showing a variable compression ratio mechanism 1 according to a first embodiment of the present invention. It is explanatory drawing which shows the state which has the master connecting rod 5 of the variable compression ratio mechanism 1 which concerns on 1st Embodiment of this invention in the lowest position. It is explanatory drawing which shows the state which the master connecting rod 5 of the variable compression ratio mechanism 1 which concerns on 1st Embodiment of this invention rotated 45 degrees clockwise from the lowest position. It is explanatory drawing which shows the state which the master connecting rod 5 of the variable compression ratio mechanism 1 which concerns on 1st Embodiment of this invention rotated 90 degrees clockwise from the lowest position. It is explanatory drawing which shows the state which the master connecting rod 5 of the variable compression ratio mechanism 1 which concerns on 1st Embodiment of this invention rotated 135 degrees clockwise from the lowest position. It is explanatory drawing which shows the state which has the master connecting rod 5 of the variable compression ratio mechanism 1 which concerns on 1st Embodiment of this invention in the uppermost position. It is explanatory drawing which shows the state which the master connecting rod 5 of the variable compression ratio mechanism 1 which concerns on 1st Embodiment of this invention rotated 45 degrees clockwise from the uppermost position. It is explanatory drawing which shows the state which the master connecting rod 5 of the variable compression ratio mechanism 1 which concerns on 1st Embodiment of this invention rotated 90 degrees clockwise from the uppermost position. It is explanatory drawing which shows the state which the master connecting rod 5 of the variable compression ratio mechanism 1 which concerns on 1st Embodiment of this invention rotated 135 degrees clockwise from the uppermost position. It is explanatory drawing about the change of the compression ratio by the position of the compression ratio change member which concerns on 1st Embodiment of this invention, (a) is when the front-end | tip 53a of the compression ratio change member 53 exists in the center in the left-right direction. It is explanatory drawing which shows the state which piston 3 exists in a top dead center in one cylinder 2, (b) is explanatory drawing which shows the state which piston 3 exists in bottom dead center in one cylinder 2, (c) These are explanatory drawings which show the state in which the piston 3 is at the top dead center in one cylinder 2 when the front end 53a of the compression ratio changing member 53 is at the left side position in the left-right direction. FIG. 3 is an explanatory view showing a state where a piston 3 is at a bottom dead center in a cylinder 2. It is explanatory drawing about the support position change mechanism of the variable compression ratio mechanism which concerns on the modification of this invention, (a) is explanatory drawing which shows the state which has the master connecting rod 5 in the lowest position, (b) It is explanatory drawing which shows the state which the master connecting rod 5 rotated 90 degrees clockwise from the lowest position, (c) is explanatory drawing which shows the state which has the master connecting rod 5 in the highest position, (d) is FIG. 6 is an explanatory view showing a state in which the master connecting rod 5 is rotated 60 ° clockwise from the uppermost position. It is a schematic plan view which shows 1A of variable compression ratio mechanisms which concern on the modification of this invention. It is a schematic side view which shows 1A of variable compression ratio mechanisms which concern on the modification of this invention. It is explanatory drawing which shows the example of mounting to the vehicle of the variable compression ratio mechanism 1 which concerns on the modification of this invention, (a) is a figure which shows the state mounted in the passenger car 100, (b) is mounted in the truck 200. It is a figure which shows a state. It is a schematic front view which shows the variable compression ratio mechanism 1B which concerns on the modification of this invention, (a) is a figure which shows the state which the master connecting rod 5C slid clockwise, (b) is the master connecting rod 5C. It is a figure which shows the state which slid counterclockwise.

Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. Note that, in the description of the second and subsequent embodiments, the same reference numerals are given to the same components and the like as those in the first embodiment, and the description thereof is omitted.
[First Embodiment]

  FIG. 1 is a schematic front view showing a variable compression ratio mechanism 1 according to the first embodiment of the present invention. FIG. 2 is a schematic plan view showing the variable compression ratio mechanism 1 according to the first embodiment of the present invention.

  As shown in FIGS. 1 and 2, the variable compression ratio mechanism 1 according to the present embodiment is employed in a star engine, and is inserted into four cylindrical cylinders 2 and four cylinders 2, respectively. Four substantially cylindrical pistons 3, four connecting rods 4 connected to the four pistons 3, a master connecting rod 5 to which the four connecting rods 4 are connected, a crankshaft 6, a balance weight 7, and a supporting position And a change mechanism 8.

  By inserting the piston 3 corresponding to each cylinder 2, a combustion chamber S is formed between the cylinder 2 and the piston 3. Although not shown in FIGS. 1 and 2, an intake valve, an exhaust valve, and a spark plug are connected to the cylinder 2. Each connecting rod 4 has a long flat plate shape, and pistons 3 are connected to one end side so as to be swingable.

  The master connecting rod 5 has a substantially rectangular flat plate shape. An insertion hole 51 is formed in the approximate center, and the other end of each connecting rod 4 is connected to the periphery of the insertion hole 51 in a swingable manner. Two engagement holes 52 are formed. Further, a rod-shaped compression ratio changing member 53 extends from the central portion of the master connecting rod 5 in the longitudinal direction. The compression ratio changing member 53 can swing around its tip 53a, and its tip 53a is It is supported so as to be movable in the vertical direction in FIG.

  The crankshaft 6 (see FIG. 2) includes a crank journal 61 serving as a rotation shaft, and a crank pin 62 that protrudes in the radial direction from the crank journal 61 and is inserted into the insertion hole 51 of the master connecting rod 5. The balance weight 7 is for reducing the inertia force generated by the movement of the piston 3, and is connected to the crank journal 61.

Under such a configuration, ignition is performed sequentially into the combustion chamber S of each cylinder 2 by the spark plug, and each piston 3 sequentially performs piston motion in each cylinder 2.
FIG. 3A is an explanatory diagram showing a state where the master connecting rod 5 of the variable compression ratio mechanism 1 according to the first embodiment of the present invention is in the lowest position. FIG. 3B is an explanatory diagram showing a state in which the master connecting rod 5 of the variable compression ratio mechanism 1 according to the first embodiment of the present invention is rotated 45 ° clockwise from the lowest position. FIG. 3C is an explanatory diagram illustrating a state in which the master connecting rod 5 of the variable compression ratio mechanism 1 according to the first embodiment of the present invention is rotated 90 ° clockwise from the lowest position. FIG. 3D is an explanatory diagram illustrating a state in which the master connecting rod 5 of the variable compression ratio mechanism 1 according to the first embodiment of the present invention is rotated 135 ° clockwise from the lowest position.

  FIG. 3E is an explanatory diagram showing a state where the master connecting rod 5 of the variable compression ratio mechanism 1 according to the first embodiment of the present invention is in the uppermost position. FIG. 3F is an explanatory diagram showing a state in which the master connecting rod 5 of the variable compression ratio mechanism 1 according to the first embodiment of the present invention is rotated 45 ° clockwise from the uppermost position. FIG. 3G is an explanatory diagram showing a state in which the master connecting rod 5 of the variable compression ratio mechanism 1 according to the first embodiment of the present invention is rotated 90 ° clockwise from the uppermost position. FIG. 3H is an explanatory view showing a state in which the master connecting rod 5 of the variable compression ratio mechanism 1 according to the first embodiment of the present invention is rotated 135 ° clockwise from the uppermost position.

  Specifically, first, from the state of each piston 3 shown in FIG. 3A, the spark plug connected to the upper right cylinder 2 is ignited, and then the spark plug connected to each cylinder 2 is ignited clockwise. The When the ignition plugs are sequentially ignited in this way, each combustion chamber S expands, and a force for rotating the master connecting rod 5 about the axis of the crank journal 61 is transmitted via the connecting rod 4. The

  3B, the upper right combustion chamber S expands and the lower left combustion chamber S is compressed, and in FIG. 3C, the lower right combustion chamber S expands and the upper left combustion chamber S is compressed, via FIG. 3D. In FIG. 3E, the lower left combustion chamber S expands and the upper right combustion chamber S is slightly compressed. 3F, the upper left combustion chamber S expands and the lower right combustion chamber S is compressed, and in FIG. 3H via FIG. 3G, the upper left combustion chamber S expands to form the lower right combustion chamber S. Compressed and returns to the state shown in FIG. 3A.

  In this way, the pistons 3 sequentially perform the piston movement, so that the master connecting rod 5 connected to the pistons 3 performs the rotational movement around the axis of the crank journal 61.

  Here, in the present embodiment, the tip 53a of the compression ratio changing member 53 is supported so as to be movable in the vertical direction along with the swinging motion of the master connecting rod 5, but this support position is a lever-like support position. It can be changed in the left-right direction by a change mechanism 8 (see FIG. 1). Specifically, the support position changing mechanism 8 is configured by a cylinder device, and the portion connected to the tip 53a of the compression ratio changing member 53 expands and contracts to support the tip 53a of the compression ratio changing member 53. The position is changed. The compression ratio is changed by changing the support position. The support position changing mechanism 8 is controlled by a control device (not shown).

  For example, by moving the support position of the tip 53a of the compression ratio changing member 53 in the left-right direction, as shown in FIG. 4C, the connecting rod 4 on the compression side (upper right) approaches the top dead center. Since it has an angle with respect to the cylinder 2, the distance at which the piston 3 is inserted into the cylinder 2 is shorter than the same distance in FIG. Therefore, when the tip 53a of the compression ratio changing member 53 is positioned at the center in the left-right direction (FIG. 4A), and when the tip 53a of the compression ratio changing member 53 is shifted from the center (FIG. 4C). )), The top dead center is different, the distance d11 and the distance d12 are different, that is, the compression ratio is changed.

  4A and 4B are explanatory views for changing the compression ratio depending on the position of the compression ratio changing member according to the first embodiment of the present invention. FIG. 4A shows the center 53 of the compression ratio changing member 53 in the left-right direction. It is explanatory drawing which shows the state which piston 3 exists in a top dead center in one cylinder 2 when it exists in (b), (b) is explanatory drawing which shows the state which piston 3 exists in bottom dead center in one cylinder 2 (C) is explanatory drawing which shows the state in which the piston 3 exists in a top dead center in one cylinder 2 when the front-end | tip 53a of the compression ratio change member 53 exists in the left side position in the left-right direction, These are explanatory drawings which show the state in which piston 3 exists in a bottom dead center in one cylinder 2. FIG.

  On the other hand, the distance by which the support position of the tip 53a of the compression ratio changing member 53 is moved to the left and right is absorbed by the connecting rod 4 on the compression side (lower left) as shown in FIG. Therefore, the connecting rod 4 on the expansion side (upper right) located near the bottom dead center is not required to have an angle with respect to the cylinder 2. Therefore, regarding the bottom dead center, the tip 53a of the compression ratio changing member 53 is displaced from the center when the tip 53a of the compression ratio changing member 53 is positioned at the center in the left-right direction (FIG. 4B). In the case (FIG. 4 (d)), the positions are substantially the same, and the distance d21 and the distance d22 are the same positions, so the displacement is also substantially equal.

  According to this embodiment, the following effects are produced.

  In the present embodiment, the support position of the distal end 53a of the compression ratio changing member 53 fixed so as to be movable only in the vertical direction can be moved in the left-right direction by the support position changing mechanism 8.

  As a result, not only the compression ratio but also the expansion ratio can be changed. For example, when combustion is performed at an optimal compression ratio of 12, the expansion ratio after combustion becomes 12 or more, so that the gas pressure can be effectively used and converted into more power. This means that a higher expansion ratio can be achieved as the amount of fuel is burned.

  Further, the four cylinders 2 are connected to the master connecting rod 5 via the connecting rods 4, and only the master connecting rod 5 needs to be connected to the crankshaft 6. Therefore, the crankshaft 6 can be shortened. As a result, it is possible to simultaneously realize weight reduction, compactness, low friction, and high rigidity in the crank mechanism.

  The support position changing mechanism 8 is a lever (lever-like member) that is swingably connected to the compression ratio changing member 53. Thereby, it becomes possible to move the support position of the front-end | tip 53a of the compression ratio change member 53 with a simple structure.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

  For example, in the above embodiment, the tip 53a of the compression ratio changing member 53 is supported so as to be swingable and movable only in the vertical direction in FIG. 1, but the portion other than the tip 53a is swingable. And it may be supported so that a movement only to the up-down direction in FIG. Further, the tip 53a may be supported so as to be movable in one direction other than the vertical direction, and the support position changing mechanism 8 moves the tip 53a not only in the horizontal direction but also in a direction intersecting with the one direction. Also good.

Further, in the above embodiment, the lever-like support position changing mechanism 8 is controlled by a control device (not shown), and the tip 53a of the compression ratio changing member 53 is set as a predetermined position in the left-right direction, and in that position, the position is changed vertically. Although it was made movable, it is not limited to this. For example, as shown in FIG. 5, a cam portion 66 that is driven by two gears 65 and 65 to which rotational torque is transmitted from the crankshaft 6 (see FIG. 2) is provided as a support position changing mechanism. An intermediate portion of the compression ratio changing member 53 instead of the distal end 53a may be coupled to the fixing portion 661 of the 66 such that the compression ratio changing member 53 is swingably supported with respect to the fixing portion 661. As a result, it is possible to prevent the compression ratio from becoming uneven in the left and right banks.
FIG. 5 is an explanatory view of a support position changing mechanism of a variable compression ratio mechanism according to a modification of the present invention, and (a) is an explanatory view showing a state in which the master connecting rod 5 is at the lowest position. (b) is an explanatory view showing a state in which the master connecting rod 5 is rotated 90 ° clockwise from the lowest position, and (c) is an explanatory view showing a state in which the master connecting rod 5 is in the uppermost position, (D) is explanatory drawing which shows the state which the master connecting rod 5 rotated 60 degrees clockwise from the uppermost position.

  In the above embodiment, the four cylinders 2 have a star structure connected to the same master connecting rod 5. However, as shown in FIGS. Alternatively, a V-type variable compression ratio mechanism 1A in which two pistons 3 are connected to the two master connecting rods 5A and 5B may be employed.

In this case, the master connecting rod 5A (5B) has a substantially V shape, and the insertion hole 51a (51b) is connected to the V-shaped base portion and the connecting rod 4 is swingably connected to both V-shaped tip portions. A pair of engaging holes 52a (52b) is formed. A compression ratio changing member 53 extends from the vicinity of the center of the V shape. In plan view, the two V-shaped cylinders and the compression ratio changing member 53 have a shape that is divided into three forks.
FIG. 6 is a schematic plan view showing a variable compression ratio mechanism 1A according to a modification of the present invention. FIG. 7 is a schematic side view showing a variable compression ratio mechanism 1A according to a modification of the present invention.

In addition, the variable compression ratio mechanism 1 according to the above embodiment can be mounted on a passenger car 100 (see FIG. 8A) having a large cabin. However, since the variable compression ratio mechanism 1 has a star shape, the truck 200 having a small cabin (see FIG. It is more suitable for mounting in b)). However, by dividing the plurality of cylinders 2 and pistons 3 into a plurality of groups as in the above-described variable compression ratio mechanism 1A (FIGS. 6 and 7), erosion to the cabin is reduced even when mounted on a passenger car.
FIG. 8 is an explanatory diagram showing an example of mounting the variable compression ratio mechanism 1 according to a modification of the present invention on a vehicle, (a) is a diagram showing a state where the variable compression ratio mechanism 1 is mounted on a passenger car 100, and (b) is a truck. It is a figure which shows the state mounted in 200. FIG.

  9A and 9B, a first compression ratio changing member 53A and a second compression ratio changing member 53B may be provided instead of the compression ratio changing member 53. Specifically, the lower end of the first compression ratio changing member 53A is rotated with respect to the master connecting rod 5C at a position similar to the position of the master connecting rod 5 to which the compression ratio changing member 53 is connected in the above-described embodiment. Connected movably. The second compression ratio changing member 53B has the same configuration as that of the support position changing mechanism 8, and the leading end of the extendable portion of the second compression ratio changing member 53B swings the connecting rod 4. Of the four engagement holes 52 that can be connected, the vicinity of the upper right engagement hole 52 in FIG. 9 is rotatably connected to the master connecting rod 5C. The upper end of the first compression ratio changing member 53A is rotatably connected to the upper end of the second compression ratio changing member 53B. This connecting portion is supported so as to be movable in the vertical direction.

  With this configuration, the compression ratio for each cylinder 2 can be made more uniform. FIG. 9 is a schematic front view showing a variable compression ratio mechanism 1B according to a modified example of the present invention. FIG. 9A is a view showing a state in which the master connecting rod 5C is swung clockwise, and FIG. FIG. 5 is a view showing a state where the master connecting rod 5C is slid in the counterclockwise direction.

DESCRIPTION OF SYMBOLS 1 ... Variable compression ratio mechanism 1A ... Variable compression ratio mechanism 1B ... Variable compression ratio mechanism 2 ... Cylinder 3 ... Piston 4 ... Connecting rod 5 ... Master connecting rod 5A ... Master connecting rod 6 ... Crankshaft 8 ... Supporting position change mechanism 51 ... Insertion hole 52 ... engagement hole 53 ... compression ratio changing member 53a ... tip

Claims (3)

Multiple cylinders;
A plurality of pistons respectively inserted into the plurality of cylinders;
A plurality of connecting rods swingably connected to the plurality of pistons;
A master connecting rod to which the plurality of connecting rods are swingably connected;
A compression ratio change that extends from the master connecting rod and is supported so as to be swingable and movable in a first direction so that the master connecting rod can rotate while swinging about a predetermined point. Members,
A support position change mechanism capable of changing the support position of the compression ratio change member to a position moved in a second direction intersecting the first direction;
Variable compression ratio mechanism with   The variable compression ratio mechanism according to claim 1, wherein the support position changing mechanism is a lever that is swingably connected to the compression ratio changing member.   The variable compression ratio mechanism according to claim 1 or 2, wherein at least two of the piston and the cylinder connected to the master connecting rod are disposed on the same plane.

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