JP4810370B2 - Multi-cylinder engine with variable stroke characteristics - Google Patents

Description

  In the present invention, a piston and a crankshaft are connected to a control shaft via a variable stroke link mechanism, and the variable stroke link mechanism is operated by a hydraulic actuator that drives the control shaft to change the moving stroke of the piston. The present invention relates to improvement of a variable stroke characteristic multi-cylinder engine.

Conventionally, an upper link having one end connected to the piston pin of the piston, a lower link connected to the other end of the upper link and connected to the crank pin of the crankshaft, and one end connected to the lower link, the other In a variable stroke characteristic engine having a variable stroke link mechanism comprising a control link whose end is swingably connected to the engine body, and the variable stroke of the piston is variable by driving the variable control link with a hydraulic actuator. It is known that the hydraulic actuator is provided on the control shaft (see Patent Document 1 below).
JP-A-2005-83203

  Incidentally, the hydraulic actuator shown in Patent Document 1 is provided outside the cylinder block, a housing fixed to the holder portion of the cylinder block by a fastening member, and a rotor provided with a vane that rotates integrally with the control shaft. The vane case that accommodates the rotor and the cover that covers the rotor have a problem that the number of parts is large, the assembly work is reduced, and the engine itself is enlarged. It is unsuitable for application for vehicles.

  The present invention has been made in view of such circumstances, and a novel variable stroke characteristic multi-cylinder engine that solves the above-described problems by reducing the number of parts of the hydraulic actuator and making it smaller and lighter. The purpose is to provide.

To achieve the above Symbol object, a first aspect of the present invention, a stroke characteristic variable multi-cylinder engine cylinder for a piston slidably fitted are arranged in parallel along the axis of the crankshaft Each piston and crankshaft are connected to the eccentric pin of the control shaft via a variable stroke link mechanism, and the stroke variable link mechanism is operated by a hydraulic actuator that drives the control shaft, thereby changing the moving stroke of the piston. The control shaft is divided into a first control shaft and a second control shaft in the axial direction, and the hydraulic actuator includes a housing, a cover member covering the opening of the housing, A vane case provided integrally with the vane shaft, and a vane shaft accommodated in the vane case. Made which have the first, is provided between the connection end portion which faces the second control axis, said cover member and said vane shaft, said first, not the eccentric pin and the lap of the second control shaft in position, it is characterized by being fastened together by fastening members.

To achieve the above object, an invention according to claim 2, wherein, in those of claim 1, wherein the cover member is characterized in that it is a bearing supported by the housing.

According to the present invention, the number of parts of the hydraulic actuator provided on the control shaft can be reduced, and the size and weight of the hydraulic actuator can be reduced. In addition, the assembly workability of the hydraulic actuator can be improved. Can do.

In addition, the hydraulic actuator can be fastened as close as possible to the axis of the control shaft, and the housing can be further miniaturized.

In particular , according to the invention of claim 2 , the hydraulic actuator can be stably supported on the housing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on reference examples shown in the accompanying drawings and examples of the present invention.

First, a first reference example will be described with reference to FIGS.

  1 is a schematic overall perspective view of a variable stroke characteristic engine, FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1, FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 1 is a sectional view taken along line 4-4 in FIG. 1 (low compression ratio state), FIG. 5 is a sectional view taken along line 5-5 in FIG. 2, and FIG. 6 is a sectional view taken along line 6-6 in FIG. 7 is an enlarged vertical view taken along line 7-7 in FIG. 5, FIG. 8 is a sectional view taken along line 8-8 in FIG. 3, and FIG. 9 is a perspective view taken along arrow 9 in FIG. FIG. 10 is an exploded perspective view of the hydraulic actuator, and FIG. 11 is a hydraulic circuit diagram of a control system of the hydraulic actuator.

  1 to 4, a variable stroke characteristic engine E according to the present invention is for an automobile and is placed horizontally in an engine room of an automobile (not shown) (the crankshaft 30 is arranged laterally with respect to the traveling direction of the automobile). ). When the engine E is mounted on a vehicle, as shown in FIG. 2, the cylinder E is slightly tilted backward, that is, its cylinder axis LL is slightly tilted backward with respect to the vertical line.

  The variable stroke characteristic engine E is an in-line four-cylinder OHC type four-cycle engine. The engine body 1 includes a cylinder block 2 in which four cylinders 5 are provided in parallel in the lateral direction, and the cylinder block. The cylinder head 3 is integrally coupled to the two deck surfaces via the gasket 6, the upper block 40 (upper crankcase) is integrally formed at the lower portion of the cylinder block 2, and is integrally coupled to the lower surface thereof. The lower block 41 (lower crankcase) is provided, and the crankcase 4 is formed by the upper block 40 and the lower block 41. A head cover 9 is integrally crowned on the upper surface of the cylinder head 3 via a sealing material 8, and an oil pan 10 is integrally coupled to the lower surface of the lower block 41 (lower crankcase). .

  Pistons 11 are slidably fitted to the four cylinders 5 of the cylinder block 2, and four combustion chambers 12 are provided on the lower surface of the cylinder head 3 facing the top surfaces of the pistons 11. An intake port 14 and an exhaust port 15 communicating with those combustion chambers 12 are formed. An intake valve 16 is provided in the intake port 14 and an exhaust valve 17 is provided in the exhaust port 15 so as to be opened and closed. On the cylinder head 3, a valve operating mechanism 18 for opening and closing the intake valve 16 and the exhaust valve 17 is provided. The valve mechanism 18 swings on an intake side cam shaft 20 and an exhaust side cam shaft 21 that are rotatably supported by the cylinder head 3, and on an intake side and exhaust side rocker shafts 22, 23 provided on the cylinder head 3. The intake side and exhaust side camshafts 20 and 21 and the intake side and exhaust side rocker arms 24 and 25 connected to the intake valve 16 and the exhaust valve 17 so as to be pivotally supported are provided. According to the rotation of the shafts 20 and 21, the intake side and exhaust side rocker arms 24 and 25 are swung against the valve closing force of the valve springs 26 and 27 to open and close the intake valve 16 and the exhaust valve 17 at a predetermined timing. Can be operated.

  As shown in FIG. 2, the intake-side and exhaust-side camshafts 20, 21 are interlocked with a crankshaft 30 described later via a conventionally known timing transmission mechanism 28, and according to the rotation of the crankshaft 30, It is driven at half the rotational speed. The valve mechanism 28 is covered with a head cover 9 that is integrally crowned on the cylinder head 3. The cylinder head 3 is provided with a cylindrical plug insertion cylinder 31 corresponding to the four cylinders, and a spark plug 32 is inserted into the plug insertion cylinder 31.

  The plurality of intake ports 14 corresponding to the four cylinders 5 are opened toward the front surface of the engine body 1, that is, the front side of the vehicle, and an intake manifold 34 of the intake system IN is connected thereto. Since the intake system IN has a conventionally known structure, a detailed description thereof will be omitted.

  A plurality of exhaust ports 15 corresponding to the four cylinders 5 are opened toward the rear surface of the engine body 1, that is, the rear side of the vehicle, and an exhaust manifold 35 of the exhaust system EX is connected thereto. . Since the exhaust system EX has a conventionally known structure, a detailed description thereof is omitted.

  As shown in FIGS. 3 and 4, the crankcase 4 including the upper block 40 (upper crankcase) at the lower part of the cylinder block 2 and the lower block 41 (lower crankcase) is more forward than the cylinder 5 part of the cylinder block 2. It projects to the (vehicle front) side, and in the crank chamber CC of the projecting portion 36, a stroke variable link mechanism LV (described later) that makes the moving stroke of the piston 11 variable, and a hydraulic actuator AC ( Provided below).

  As shown in FIGS. 2, 3 and 5, 6, a lower block 41 is fixed to the lower surface of the upper block 40 integrally formed at the lower portion of the cylinder block 2 with a plurality of connecting bolts 42. The journal shaft 30J of the crankshaft 30 is rotatably supported by a plurality of journal bearing portions 43 formed on the mating surfaces of the upper block 40 and the lower block 41 (see FIG. 8).

  As shown in FIG. 5, the lower block 41 is cast and molded in a closed cross-sectional structure having a square shape in plan view. End bearing members 50 and 51 are provided at the left and right ends thereof, and an intermediate portion thereof is provided at In the center of the left and right intermediate bearing members 52 and 53, a central bearing member 54 (a housing HU described later is integrally formed) is provided as a bearing cap. The journal shaft 30J of the crankshaft 30 is supported.

  As shown in FIGS. 5, 6, and 9, the central bearing member 54 as the bearing cap is cast and formed separately from the lower block 41, and the side surface of the lower block 41 is secured by a plurality of bearing cap tightening bolts 56. The central bearing member 54 is also firmly fixed to the lower surface of the upper block 40 by other bearing cap tightening bolts 57. One side portion of the central bearing member 54 that is biased from the bearing portion 54A of the crankshaft 30 to the one side (the front side of the engine body 1) is an enormous portion 58 having an enlarged vertical width and a large thickness. A housing HU of a hydraulic actuator AC, which will be described in detail later, is cast into the enormous portion 58.

  Next, returning to FIGS. 3 and 4, the structure of the variable stroke link mechanism LV that makes the moving stroke of the piston 11 variable will be described. A crank that is rotatably supported on the mating surface of the upper block 40 and the lower block 41. An intermediate portion of a triangular lower link 60 is pivotally connected to the plurality of crank pins 30P of the shaft 30 so as to be swingable. One end (upper end) of the lower link 60 is pivotally connected to the lower end (large end) of an upper link (connecting rod) 61 pivotally connected to the piston pin 13 of the piston 11 via a first connecting pin 62. The upper end of the control link 63 is pivotally connected to the other end (lower end) of each lower link 60 via the second connecting pin 64. The control link 63 extends downward, and an eccentric pin 65P of a control shaft 65 (detailed later) is pivotally connected to the lower end of the control link 63. The control shaft 65 is driven within a predetermined angle range (about 90 degrees) by a hydraulic actuator AC (described in detail later), and the control link 63 is driven to swing by the displacement of the eccentric pin 65P. Specifically, the control shaft 65 rotates between a first position shown in FIG. 3 (the eccentric pin 65P is a lower position) and a second position shown in FIG. 4 (the eccentric pin 65P is a left position). Is possible. In the first position shown in FIG. 3, the eccentric pin 65P of the control shaft 65 is positioned below, so that the control link 63 is pulled down and the lower link 60 swings clockwise around the crank pin 30P of the crankshaft 30. As a result, the upper link 61 is pushed up, and the position of the piston 11 becomes higher than the cylinder 5, and the engine E enters a high compression ratio state. On the other hand, in the second position shown in FIG. 4, the eccentric pin 65P of the control shaft 65 is located to the left (higher than the first position), so that the control link 63 is pushed up to lower link 60. Swings counterclockwise around the crank pin 30P of the crankshaft 30, the upper link 61 is pushed down, and the position of the piston 11 is lowered with respect to the cylinder 5, and the engine E enters a low compression ratio state. As described above, by the rotation control of the control shaft 65, the control link 63 swings, the motion constraint condition of the lower link 60 changes, and the stroke characteristics including the top dead center position of the piston 11 change. It becomes possible to arbitrarily control the compression ratio of the engine E.

  Thus, the upper link 60, the first connecting pin 62, the lower link 60, the second connecting pin 64, and the control link 63 constitute a variable stroke link mechanism LV according to the present invention.

  As shown in FIGS. 6, 7, 9, and 10, the control shaft 65 that is connected to the control link 63 and operates the stroke variable link mechanism LV includes a plurality of journal shafts 65 </ b> J and eccentric pins 65 </ b> P, like the crankshaft 30. Are alternately connected via the arms 65A to form a crank shape, and a cylindrical vane shaft 66 is integrally provided between the eccentric pins 65P in the center in the axial direction. The control shaft 65 is biased to one side of the lower block 41 (the front side of the engine body 1), and the journal shaft 65J is a bearing that is fixed to the lower block 41 and a plurality of connecting bolts 68 on the lower surface thereof. It is rotatably supported between the block 70. The bearing block 70 includes a vertical frame 71 that extends in the axial direction of the control shaft 65, a plurality of bearing walls 72 that stand up together with the vertical frame 71, and a central housing receiving portion 73. And formed on a mating surface between the upper surfaces of the plurality of bearing walls 72 and the lower surfaces of the bearing walls 50a, 51a, 52a, 53a extended from the bearing members 50, 51, 52, 53 of the lower block 40. The journal shaft 65J of the control shaft 65 is rotatably supported by the bearing portion.

  As will be described later, the lower portion of the housing HU provided on the central bearing member 54 is fixedly supported by a plurality of bolts 74 on the central housing receiving portion 73 formed in the bearing block 70 (see FIG. 6).

  As shown in FIGS. 6 and 7, the hydraulic actuator AC that drives the control shaft 65 is provided in the crank chamber CC of the engine body 1, and the housing HU of the hydraulic actuator AC that accommodates and supports the hydraulic drive unit is: The central bearing member 54 (fixed integrally with the upper block 40 and the lower block 41) is provided at the enlarging portion 58 on one side. The housing HU is formed with a short cylindrical through hole 80 whose both end faces are open, and a vane case 79 is formed integrally with the inner peripheral surface of the through hole 80. In the vane case 79, a vane shaft 66 formed integrally with the central portion in the longitudinal direction of the control shaft 65 is accommodated, and a phase difference of about 180 ° exists at the outer peripheral central portion of the vane shaft 66. Thus, a pair of vanes 87 are integrally projected. The left and right sides of the vane shaft 66 are rotatably supported by cover members 81 and 82 fixed by a plurality of bolts 83 on both sides of the housing HU. The opening side surface of the housing HU is closed by the cover members 81 and 82. A pair of fan-shaped vane oil chambers 86 are defined between the inner peripheral surface of the vane case 79 and the vane shaft 66 with a phase difference of about 180 °. A pair of vanes 87 projecting integrally from the outer peripheral surface of the shaft 66 are accommodated, and each vane 87 is oil-tightly partitioned in the fan-shaped vane oil chamber 86 into two control oil chambers. By controlling the supply and discharge of hydraulic oil from a hydraulic circuit, which will be described later, to one control oil chamber, the vane shaft 66 can be reciprocated within a predetermined angle range together with the control shaft 65.

  As described above, the housing HC of the hydraulic actuator AC that drives the control shaft 65 is compact using the central bearing member of the lower block 41 (formed separately from the lower block 41 and fixed thereto). In addition, the number of parts can be reduced, the volume occupied by the housing HC in the crank chamber CC can be reduced, and the bulk of the crankcase can be prevented from increasing.

  As shown in FIGS. 5, 7, and 9, the upper surface of the housing HU formed in the central bearing member 54 is flat and spreads in a dovetail shape from the bearing portion 54 </ b> A of the crankshaft 30 toward the end portion on the housing HU side. As shown in FIG. 7, the width D1 of the mounting surface 90 in the direction of the control shaft 65 is wider than the width D2 of the housing HU. A valve unit 92 of a hydraulic control circuit of the hydraulic actuator AC is fixedly supported by a plurality of bolts 91, and this valve unit 92 passes through the wall surface of the cylinder block 2 and is disposed in an exposed state on the upper surface (see FIG. 1). As a result, the valve unit 92 can be firmly fixed on the mounting surface of the housing HU. The valve unit 92 is on the mounting wall surface of the cylinder block 2 and is open on all four sides. The switching operation and maintenance of the actuator AC are facilitated.

  Next, a hydraulic circuit of a hydraulic actuator AC that drives and controls the stroke variable link mechanism LV will be described with reference to FIG.

  As described above, the two control oil chambers partitioned by the vanes 87 in the pair of fan-shaped vane oil chambers 86 formed by the vane shaft 66 of the control shaft 65 and the housing HU are oiled via a hydraulic circuit. An oil pump P driven by a motor M, a check valve C, an accumulator A, and an electromagnetic switching valve V are connected to the hydraulic circuit of the tank T. An oil tank T, a motor M, an oil pump P, a check valve C, and an accumulator A constitute a hydraulic pressure supply device S, which is provided at an appropriate position of the engine body 1, and an electromagnetic switching valve V is provided inside the valve unit 92 described above. Is provided. The hydraulic pressure supply device S and the electromagnetic switching valve V are connected by two pipes P1 and P2, and the electromagnetic switching valve V and the hydraulic actuator AC are connected by two pipes P3 and P4. Therefore, in FIG. 11, the vane 87 is pushed by the hydraulic pressure generated by the oil pump P that switches the electromagnetic switching valve V to the left, and the control shaft 65 rotates counterclockwise. Conversely, the electromagnetic switching valve V is moved to the right. The phase of the eccentric pin 65P of the control shaft 65 changes when the vane 87 is pushed by the hydraulic pressure generated by the oil pump P to be switched and the control shaft 65 rotates clockwise. The control link 63 of the stroke variable link mechanism LV is pivotally connected to the eccentric pin 65P of the control shaft 65 so that the control pin 65 is driven (about 90 °), and the eccentric pin 65P of the control shaft 65 is driven. As described above, the stroke variable link mechanism LV is operated by the phase change.

By the way, according to the first reference example, the hydraulic actuator AC that drives the control shaft 65 is provided in the central portion of the control shaft 65, the housing HU provided in the central bearing member 54, and the housing HU. Since the cover members 81 and 82 covering the opening, the vane case 79 formed integrally with the inner peripheral surface of the housing HU, and the vane shaft 66 provided integrally with the control shaft 66 are formed, the hydraulic actuator AC The number of parts can be reduced, and the weight and size thereof can be reduced. In addition, the assembly work efficiency of the hydraulic actuator is improved.

It will now be described real施例of the present invention with reference to FIG. 12-15.

12 is a vertical side view of the support portion of the control shaft (corresponding to FIG. 7 of the first reference example), and FIG. 13 is a cross-sectional view taken along line 13-13 of FIG. 12 (corresponding to FIG. 6 of the first reference example). 14 is a perspective view of the control shaft and the central bearing member, and FIGS. 15A and 15B are exploded and assembled perspective views of the control shaft. In the figure, the same elements as those of the first reference example are shown. Are given the same reference numerals.

  12 to 15, the control shaft 65 provided with the hydraulic actuator AC is divided into a first control shaft 65-1 and a second control shaft 65-2 from the center in the longitudinal direction, and their connection end faces ( Disc-shaped cover members 181 and 182 forming a pair of hydraulic actuators AC are concentrically and integrally coupled to the end surface of the eccentric pin 65P, and a fastening member is provided at the center of the inner surface of these cover members 181 and 182. That is, the vane shaft 66 provided with a pair of vanes 87 is fixed by a plurality of bolts 67, whereby the first and second control shafts 65-1, 65-2, the cover members 181, 182 and the vane shaft 66 are It is united. In this case, the bolt 67 fastens the first and second control shafts 65-1 and 65-2, the cover members 181 and 182, and the vane shaft 66 at a position where the bolt 67 does not overlap with the eccentric pin 65 </ b> P of the control shaft 65. The fastening position can be as close as possible to the axis of the control shaft 65.

As shown in FIGS. 12 and 13, the control shaft 65 passes through the housing HU, and the vane shaft 66 is accommodated in a vane case 79, and a pair of vane oil chambers 86 are formed therebetween. The vane 87 divides the inside of the vane oil chamber 86 into two control oil chambers as in the first reference example. The cover members 181 and 182 are rotatably supported by bearings via packings 88 on both sides in the housing HU. The packing 88 is provided outside the vane 87 in the radial direction and between the housing HU of the actuator AC and the cover members 181 and 182.

  Since the cover members 181 and 182 are supported by the housing HU in bearings, the actuator AC can be stably supported by the housing HU.

As in the first reference example, by controlling the supply of hydraulic oil from the hydraulic pump P of the hydraulic circuit to the vane oil chamber 86, the hydraulic actuator AC is reciprocated at a predetermined angle, and the stroke variable link mechanism LV is activated. Is done.

Thus, according to the embodiment of the present invention , the cover member cover members 181 and 182 and the vane shaft 66 are integrally formed in the central portion of the control shaft 65, so that the hydraulic actuator AC can reduce the number of parts. It can be reduced to be small and light, the occupied space in the crank chamber CC can be reduced, the degree of freedom in mounting can be increased, and the assembly workability is good.

Next, a second reference example will be described with reference to FIGS.

Figure 16 is a partial longitudinal sectional side view of the control shaft and a hydraulic actuator, FIG. 17 is a perspective view of the control shaft, in the figure, the same elements as the first reference example the same numerals are attached.

In the second reference example, a hydraulic actuator AC is provided at the end of the control shaft 65. A vane shaft 66 provided with a pair of vanes 87 is formed integrally with the journal shaft 65J at the end of the control shaft 65. On the other hand, a hydraulic actuator AC that drives the control shaft 65 is provided at the end of the control shaft 65. The housing HU of the hydraulic actuator AC is fixedly supported at appropriate positions on the engine body 1, and cover members 281 and 282 are fixed to both side surfaces of the housing HU by fastening members, that is, a plurality of bolts 283. , 282, the vane shaft 66 at the end of the control shaft 65 is rotatably supported. In the vane chamber 82 defined by the housing HU and the cover members 281 and 282, the aforementioned vane hydraulic drive unit of the hydraulic actuator AC is provided.

In the second reference example, since the vane shaft 66 having the vane 87 of the hydraulic actuator AC is integrally formed with the control shaft 65, the number of parts of the hydraulic actuator AC is reduced and the size is reduced. Thus, the weight can be reduced and the assembling workability can be improved.

Next, a third reference example will be described with reference to FIG.

FIG. 18 is a partially longitudinal side view of the control shaft and the hydraulic actuator, in which the same elements as those in the first reference example are denoted by the same reference numerals.

This third reference example is also a case where a hydraulic actuator AC is provided at the end of the control shaft 65 as in the first reference example. The journal shaft 65J at the end of the control shaft 65 is integrally formed with a vane shaft 66 provided with a pair of vanes 87 and a cover member 381 of the hydraulic actuator AC. The housing HU of the hydraulic actuator AC is fixedly supported at an appropriate position of the engine body 1, and the end portion of the control shaft 65 in which the vane shaft 66 and the cover member 381 are integrally formed is assembled to the housing HU. In the vane chamber 82 defined by the housing HU and the cover member 381, a vane type hydraulic drive unit of the hydraulic actuator AC is provided as in the first reference example.

Thus, in the third reference example, the vane shaft 66 and the cover member 381 in which the vane 87 of the hydraulic actuator AC is integrally formed with the control shaft 65 are integrally formed. Therefore, the number of parts of the hydraulic actuator AC is reduced. Thus, the size and weight can be reduced, and the assembly workability can be improved.

As mentioned above, although the reference example and the Example of this invention were demonstrated, this invention is not limited to the Example, A various Example is possible within the scope of the present invention.

For example, in the above embodiment, the case where the present invention is a variable compression ratio engine that changes the top dead position of the piston by changing the phase of the eccentric pin of the control shaft has been described. Is also applicable. In the above embodiment, the vane case is formed integrally with the housing, but a separate vane case may be fixed to the housing.

1 is a schematic overall perspective view of a variable stroke characteristic engine according to a first reference example. 2 arrow view of FIG. Sectional view along line 3-3 in FIG. 1 (high compression ratio state) Sectional view along line 4-4 in FIG. 1 (low compression ratio state) Sectional view along line 5-5 in FIG. Cross-sectional view along line 6-6 in FIG. Enlarged vertical view along line 7-7 in FIG. Sectional view along line 8-8 in FIG. 9 perspective view of FIG. Exploded perspective view of hydraulic actuator Hydraulic circuit diagram of hydraulic actuator control system FIG. 3 is a longitudinal side view of the support portion of the control shaft according to the embodiment of the present invention . Sectional drawing which follows the 13-13 line of FIG. Perspective view of control shaft and center bearing member Disassembled and assembled perspective view of control shaft Partial vertical side view of the control shaft and actuator according to the second reference example Perspective view of control shaft Partial vertical side view of the control shaft and actuator according to the third reference example

11. Piston 30 ... Crankshaft 65 ... Control shaft 65-1 ... First control shaft 65-2 ... First 2 Control shaft 65P ···························· Eccentric Pin 67 Cover member 181 ... Cover member 182 ... Cover member AC ... Hydraulic actuator LV ... Variable stroke link mechanism HU ... housing

Claims (2)

Cylinder for slidably fitted a piston (11) (5) is a stroke characteristic variable multi-cylinder engine are arranged in parallel along the axis of the crank shaft (30),
A hydraulic actuator that connects each piston (11) and crankshaft (30) to an eccentric pin (65P) of a control shaft (65) via a variable stroke link mechanism (LV) and drives the control shaft (65) (AC) actuating the variable stroke link mechanism (LV) to change the moving stroke of the piston (11),
The control shaft (65) is divided in the axial direction into a first control shaft (65-1) and a second control shaft (65-2),
The hydraulic actuator (AC) includes a housing (HU), cover members (181, 182) covering an opening of the housing (HU), a vane case (79) integrally provided in the housing (HU), The vane shaft (66) is accommodated in the vane case (79), and is provided between the connecting end portions of the first and second control shafts (65-1, 65-2) facing each other. And
Said cover member (181, 182) and said vane shaft (66), the first, by the eccentric pin (65P) and not wrap position of the second control shaft (65-1 and 65-2), the fastening member ( characterized in that it is fastened together by 67), the stroke characteristic variable multi-cylinder engine. It said cover member (181, 182) is characterized in that it is bearing supported on the housing (HU), stroke characteristic variable multi-cylinder engine according to claim 1.

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