JP2008190365A - Uniflow two-stroke cycle internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a uniflow two-stroke cycle internal combustion engine that provides a fine control of a swirl ratio by a vane mechanism composed of a first, a second vanes through a simple construction, and a highly accurate control of the swirl ratio. <P>SOLUTION: The uniflow two-stroke cycle internal combustion engine includes a sleeve 8 having a scavenging port 13 therein, and an air flow control device for controlling the flow of fresh air entering into a cylinder chamber 14 from the scavenging port 13 depending on engine operating condition. The air flow control device includes first and second vanes 31, 32 that form a guide passage 33 for guiding the fresh air to the scavenging port 13 so that a swirl is created in the cylinder chamber 14, and the first and second vanes 31, 32 are independent and changeable in swinging positions of each other for controlling the swirl ratio. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a uniflow type two-stroke internal combustion engine in which a flow of fresh air flowing from a scavenging port that opens to an inner peripheral surface of a cylinder generates a swirl in a cylinder chamber, and more specifically, includes a plurality of vanes that control a swirl ratio. The present invention relates to a structure of an airflow control device including a vane mechanism.

A uniflow two-stroke internal combustion engine equipped with an air flow control device that controls the flow of fresh air supplied from the scavenging port or the scavenging passage to the cylinder chamber, that is, the flow direction and flow rate of fresh air, according to the engine operating state. Are known. (For example, see Patent Documents 1 to 3)
JP-A-61-258924 Japanese Patent Laid-Open No. 61-232321 JP-A-10-196372

By the way, in a uniflow internal combustion engine in which the flow of fresh air flowing in from the scavenging port is controlled by a vane mechanism having a plurality of vanes, all the vanes are uniformly formed in the same form with a guide angle (the vanes are formed in the radial direction). Is changed), in the pair of adjacent vanes sandwiching the scavenging port in the circumferential direction (or forming a scavenging passage), the position of the other vane corresponding to the position of one vane is a pair. Therefore, in order to increase the control accuracy of the swirl ratio by the vane mechanism, it is necessary to control the position of each vane with high accuracy, and with a simple structure, combustion according to engine operating conditions It is difficult to control the swirl ratio with high accuracy to improve the efficiency and scavenging efficiency.
Further, when the guide angle of the vane is changed, the effective passage area of the scavenging port or the scavenging passage is also changed accordingly, so that different swirls are obtained with the same effective passage area of each scavenging port or each scavenging passage. Since the ratio cannot be set, precise control for improving combustibility and scavenging efficiency by combining the swirl ratio and the effective passage area is difficult.

  This invention is made | formed in view of such a situation, and the invention of Claims 1-5 has a fine swirl ratio by the vane mechanism comprised from a 1st, 2nd vane by simple structure. An object of the present invention is to provide a uniflow type two-stroke internal combustion engine that can be controlled and can control the swirl ratio with high accuracy. The invention described in claim 3 further aims to reduce the size of the drive mechanism for driving the vane mechanism, and the invention described in claim 4 further provides a cylinder axis line by the drive mechanism for driving the vane mechanism. The object of the present invention is to further increase the swirl ratio by devising the vane support structure.

According to the first aspect of the present invention, there is provided a cylinder provided with a scavenging port opened on an inner peripheral surface with which a reciprocating piston slides, and a flow of fresh air flowing from the scavenging port into a cylinder chamber formed by the cylinder. In a uniflow type two-stroke internal combustion engine provided with an airflow control device that controls according to an engine operating state,
The airflow control device includes a first vane and a second vane that form a guide passage for guiding fresh air to the scavenging port so that a swirl is generated in the cylinder chamber, and the first airflow control device controls the swirl ratio. This is a uniflow type two-stroke internal combustion engine in which the swing positions of the first vane and the second vane can be changed independently of each other.
According to a second aspect of the present invention, in the uniflow type two-stroke internal combustion engine according to the first aspect, an effective opening area of the scavenging port is set by a passage area of the guide passage, and the effective opening area is a fluctuation of the second vane. The swirl ratio is controlled by the swing position of the first vane while being controlled by the moving position and the effective opening area is maintained substantially constant by the second vane.
According to a third aspect of the present invention, in the uniflow type two-stroke internal combustion engine according to the first or second aspect, the airflow control device changes a swing position of the first vane and the second vane, respectively. And the second drive ring, wherein the first drive ring and the second drive ring are arranged along the circumferential direction of the cylinder and arranged side by side in the cylinder axial direction.
A fourth aspect of the present invention is the uniflow type two-stroke internal combustion engine according to the third aspect, wherein the first drive ring and the second drive ring sandwich the first vane and the second vane in the cylinder axial direction. Is to be arranged.
According to a fifth aspect of the present invention, in the uniflow two-stroke internal combustion engine according to any one of the first to fourth aspects, the first vane and the second vane swing on the cylinder at an inner peripheral end portion thereof. The inner peripheral end portion is accommodated in a recess formed in a circumferential edge portion of the scavenging port of the cylinder.

According to the first aspect of the present invention, since the swing positions of the first and second vanes for guiding fresh air to the scavenging port are controlled independently of each other, the first vane and the second vane constituting the vane mechanism. Since the swing position of the other vane can be variously changed with respect to the swing position of one of the vanes, the swirl ratio can be set finely. As a result, the swirl position of the first and second vanes can be changed independently of each other, so that the swirl ratio can be finely controlled by the vane mechanism. , High-precision control of the swirl ratio becomes possible.
According to the second aspect, since various swirl ratios can be set for the same effective opening area, the swirl ratio can be finely controlled by combining the effective opening area and the swirl ratio. It is possible to set an optimal swirl ratio in terms of engine performance such as combustibility or scavenging efficiency.
According to the third aspect, since the first and second drive rings are arranged side by side in the cylinder axial direction, the drive mechanism including the first and second drive rings is downsized in the radial direction.
According to the fourth aspect of the present invention, the first and second drive rings are disposed in the end space in the cylinder axial direction with respect to the first and second vanes. Due to the drive mechanism, the cylinder is prevented from being enlarged in the cylinder axial direction.
According to the fifth aspect of the present invention, since the inner peripheral ends of the first and second vanes are accommodated in the recesses provided at the circumferential edge of the scavenging port, the inner peripheral end flows through the scavenging port. Since it does not become a resistance of fresh air, it contributes to an increase in the swirl ratio.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
Referring to FIGS. 1 and 2, a uniflow two-stroke internal combustion engine E to which the present invention is applied is an in-line four-cylinder internal combustion engine as a multi-cylinder internal combustion engine mounted on a vehicle. Is connected to the lower end portion of the cylinder block 1, the crankcase 4 is formed together with the lower portion of the cylinder block 1 to form the crankshaft 12 together with the lower portion of the cylinder block 1, and is connected to the upper end portion of the cylinder block 1. An engine main body including a cylinder head 5 and a head cover 6 coupled to the upper end of the cylinder head 5.

  In the embodiment, the vertical direction is assumed to be a direction parallel to the cylinder axis L (hereinafter referred to as “cylinder axis direction”) as shown in FIG. Further, the radial direction and the circumferential direction are respectively a radial direction and a circumferential direction around the cylinder axis L unless otherwise specified. Then, when one of the upper and lower sides is one in the vertical direction, the other of the upper and lower sides is the other in the vertical direction.

  The cylinder block 1 includes a cylinder 3 having a single cylindrical sleeve 8 into which a piston 10 connected to a crankshaft 12 via a connecting rod 11 is fitted so as to be reciprocally movable, and surrounds each sleeve 8 and each sleeve. 8 and a main body 2 that forms a scavenging chamber 9. The scavenging chamber 9 is supplied with fresh air which is air pressurized by a scavenging pump. The main body 2 is configured by joining an upper main body 2a and a lower main body 2b divided by a plane orthogonal to the cylinder axis L by a large number of bolts.

In the sleeve 8 fitted and fixed to the main body 2, a plurality of, in this embodiment, eight scavenging ports 13 opening in the inner peripheral surface 8 i with which the piston 10 is slidably contacted are spaced at equal intervals in the circumferential direction. Further, the sleeve 8 is provided so as to penetrate in the radial direction. All the scavenging ports 13 have the same shape. When the piston 10 occupies the bottom dead center, the scavenging port 13 is not closed by the piston 10 and is fully opened.
A cylinder chamber 14 into which fresh air in the scavenging chamber 9 flows through each scavenging port 13 is formed by the sleeve 8 between the piston 10 and the cylinder head 5 in the cylinder axial direction.

The cylinder head 5 includes a combustion chamber 15 formed by a recess at a position facing the cylinder chamber 14 in the cylinder axial direction, an exhaust port 16 that opens to the combustion chamber 15, an exhaust valve 17 that opens and closes the exhaust port 16, A fuel injection valve 18 that faces the combustion chamber 15 and injects fuel into the combustion chamber 15 and the cylinder chamber 14 and an ignition plug 19 that faces the combustion chamber 15 are provided.
The valve operating device disposed in the valve operating chamber 20 formed by the cylinder head 5 and the head cover 6 includes a cam shaft 21 that is rotationally driven by the power of the crank shaft 12. The exhaust valve 17 is driven to open and close in synchronization with the rotation of the crankshaft 12 by a camshaft 21 rotatably supported by the cylinder head 5, and opens and closes the exhaust port 16 at a predetermined opening / closing timing.

The internal combustion engine E includes an airflow control device that controls the flow of fresh air flowing into the cylinder chamber 14 from the scavenging port 13, that is, the flow direction, the flow velocity, and the flow rate according to the engine operating state of the internal combustion engine E. The airflow control device includes a plurality of vanes provided corresponding to each scavenging port 13, here, a vane mechanism including two vanes, a first vane 31 and a second vane 32 (hereinafter “vane mechanism”). And a first drive ring 41 and a second drive ring 42 as drive mechanisms for independently changing the swing positions of the first vane 31 and the second vane 32 in order to control the swirl ratio, The first and second electric motors 51 and 52 as actuators for generating driving force for driving the driving rings 41 and 42, respectively, and the driving force generated by the both electric motors 51 and 52 are respectively used for the first and second driving rings 41. , 42 as first and second worm gears 61, 62 serving as transmission mechanisms, detecting means 71 for detecting the engine operating state of the internal combustion engine E, and controlling the electric motors 51, 52 according to the engine operating state Control unit All electronic control units 70.
Here, the swirl ratio is a ratio of the swirling speed of the swirl generated in the cylinder chamber 14 by the fresh air flowing into the cylinder chamber 14 from each scavenging port 13 to the rotational speed of the crankshaft 12.

  3-5, all the 1st, 2nd vanes 31 and 32 which comprise a vane mechanism are in the same position in a cylinder axial direction. The width of each vane 31, 32 in the cylinder axial direction is substantially equal to the width W of the scavenging port 13 in the cylinder axial direction (see FIG. 5). The first and second vanes 31 and 32 provided for each scavenging port 13 are arranged at positions sandwiching the scavenging port 13 in the circumferential direction, and the sleeve 8 is centered on a rocking center line parallel to the cylinder axis L. Guide passage for guiding fresh air in the scavenging chamber 9 to the scavenging port 13 so that fresh air flowing into the cylinder chamber 14 from each scavenging port 13 generates a swirl in the cylinder chamber 14. 33 is formed between the first and second drive rings 41 and 42 in the cylinder axial direction. Accordingly, the guide passage 33 is constituted by the first and second vanes 31 and 32 arranged at intervals in the circumferential direction and the first and second drive rings 41 and 42 arranged at intervals in the cylinder axial direction. It is formed.

3 to 5, each of the first and second vanes 31 and 32 includes both ends in the radial direction, that is, inner peripheral ends 31 i and 32 i that are ends close to the cylinder axis L in the radial direction. And outer peripheral end portions 31o and 32o that are far from the cylinder axis L in the radial direction. The first vane 31 is a hinge provided at the inner peripheral end 31i at the circumferential edge 8b of the sleeve 8 forming the scavenging port 13 opposite to the swirl turning direction S with respect to the scavenging port 13. The portion 31h is supported so as to be swingable at the inner peripheral end portion 31i. The second vane 32 has a hinge portion 32h provided at the inner peripheral end portion 32i at the circumferential edge portion 8a of the swirling direction S of the sleeve 8 forming the scavenging port 13 with respect to the scavenging port 13. Thus, the inner peripheral end 32i is supported so as to be swingable.
Each of the hinge portions 31h and 32h is a portion provided with a through hole through which a support pin 34 as a support portion provided in the sleeve 8 is inserted. Accordingly, the hinge portions 31h and 32h are pivotally supported by the support pins 34 fixed to the sleeve 8 at both ends. The support pin 34 is inserted into the flanges 8c and 8d provided integrally with the sleeve 8 and the radial grooves 8c1 and 8d1 provided in the sleeve 8, and then comes out of the first and second drive rings 41 and 42. It is held in a stopped state.

  Referring to FIG. 3, the inner peripheral end portions 31i and 32i and the hinge portions 31h and 32h are accommodated in a recess 8e serving as an accommodating portion provided in the edge portions 8a and 8b. Outer surfaces facing the scavenging port 13 in the swinging range of the vanes 31 and 32 in the inner peripheral end portions 31i and 32i and the hinge portions 31h and 32h are formed from a cylindrical surface having the swing centerline as a central axis. 31e, 32e. At the swing position where the arcuate portions 31e and 32e face the scavenging port 13, the opening area of the scavenging port 13 hardly changes due to the inner peripheral end portions 31i and 32i and the hinge portions 31h and 32h of the vanes 31 and 32. .

  Referring to FIGS. 3 to 5, an engagement pin 35 as a vane side engagement portion protruding upward from the upper end portion is integrally formed on the outer peripheral end portion 31 o of the first vane 31. The outer peripheral end 32o of the 32 is provided with an engaging pin 36 that is integrally formed as a vane-side engaging portion that protrudes downward from the lower end.

Referring to FIGS. 1 to 5, each of the first and second drive rings 41 and 42 is a thin plate-like annular member in the cylinder axial direction, and the outer periphery of the sleeve 8 is along the circumferential direction of the sleeve 8. The sleeve 8 is disposed around the entire circumference of the sleeve 8 and is supported by the sleeve 8 and the main body 2 so as to be slidable in the circumferential direction independently of each other.
Specifically, the first drive ring 41 is supported by an annular flange portion 8c of the sleeve 8 at the inner peripheral portion, and protrudes integrally with the outer peripheral portion upward from the lower body 2b at a circumferential interval. It is supported by a plurality of provided columnar support portions 43 (see FIGS. 2 and 5). The second drive ring 42 has a plurality of columnar support portions 44 and 45 that are integrally provided so as to protrude upwardly from the lower main body 2b at intervals in the circumferential direction at portions near the inner peripheral portion and the outer peripheral portion. 2, refer to FIG. 5).

  The first and second drive rings 41 and 42 are arranged in parallel to each other and rotate in the circumferential direction on a plane orthogonal to the cylinder axis L. The distance between the first and second drive rings 41 and 42 in the cylinder axial direction is substantially equal to the width W of the scavenging port 13.

The first drive ring 41 disposed in the space 46 formed above the first and second vanes 31 and 32 in the scavenging chamber 9 engages with the ring-side engagement with the engagement pin 35 of the first vane 31. An engagement groove 48 as a joint is provided. Further, a ring in which the engagement pin 36 of the second vane 32 is engaged with the second drive ring 42 disposed in the space 47 formed below the first and second vanes 31 and 32 in the scavenging chamber 9. An engagement groove 49 is provided as a side engagement portion. Here, the two spaces 46 and 47 are end spaces formed on both end sides in the cylinder axial direction with respect to the first and second vanes 31 and 32.
Therefore, the first and second drive rings 41 and 42 are arranged side by side in the cylinder axial direction, and are arranged at positions sandwiching all the first vanes 31 and all the second vanes 32 in the cylinder axial direction. . Therefore, the first and second drive rings 41 and 42 and all the first and second vanes 31 and 32 overlap each other when viewed from the cylinder axial direction.

  Referring to FIGS. 1 and 2, the first worm gear 61 is engaged with a worm 61 a as a drive unit that is rotationally driven by an electric motor 51, and meshes with the worm 61 and is driven by the worm 61 a to rotate the cylinder axis L. A worm wheel 61b as a driven part that rotates integrally with the first drive ring 41 as a center line. The worm 61a is integrally formed with a drive shaft 53 that is connected to the rotation shaft of the electric motor 51. The worm wheel 61b is configured by a first drive ring 41 in which a meshing portion 61c with the worm 61a is provided in a part in the circumferential direction. The first drive ring 41 is rotated by being driven by the electric motor 51 to uniformly change the swing positions of all the first vanes 31.

  Similarly, the second worm gear 62 is driven by the worm 62a as a drive unit that is rotationally driven by the electric motor 52, and is driven by the worm 62a and driven by the worm 62a. A worm wheel 62b as a driven part that rotates integrally with the ring 42 is formed. The worm 62a is integrally formed with the drive shaft 54 connected to the rotation shaft of the electric motor 52. The worm wheel 62b is constituted by a second drive ring 42 in which a meshing part 62c with the worm 62a is provided in a part in the circumferential direction. The second drive ring 42 is driven by the electric motor 52 and rotates to change the swing positions of all the second vanes 32 uniformly.

Referring to FIG. 2, the detection means 71 includes a rotation speed detection means 71 a for detecting the engine rotation speed of the internal combustion engine E, and an engine of the internal combustion engine E based on the fuel injection amount or the intake air amount sucked into the scavenging pump. Load detecting means 71b for detecting a load, and signals of the detecting means 71a and 71b are input to the electronic control unit 70.
The electronic control unit 70 controls the swirl ratio based on the engine rotation speed or the engine load detected by the detection means 71a and 71b, and the first and first preset values are set in advance using the engine rotation speed and the engine load as parameters, respectively. The first and second vanes 31 and 32 are controlled such that the first and second vanes 31 and 32 occupy the swing position of the two vanes 31 and 32.

With reference to FIGS. 6-8, operation | movement of an airflow control apparatus is demonstrated.
FIG. 6 shows one form of the first and second vanes 31 and 32 when the swirl ratio is controlled by changing the positions of the first and second vanes 31 and 32 independently of each other. Since the first and second vanes 31 and 32 occupy substantially swinging positions, and the guide angles θ1 and θ2 of the first and second vanes 31 and 32 are set to be relatively large, the cylinder chamber 14 Inside, a swirl with a relatively large swirl ratio is generated. At this time, the effective opening area of the scavenging port 13 (hereinafter referred to as “effective opening area”) is determined by the minimum area of the passage area A of the first and second vanes 31 and 32.

  Here, the effective opening area of the scavenging port 13 is an opening area that regulates the flow rate of fresh air flowing from the scavenging port 13, and depends on the swing positions of the first and second vanes 31 and 32. The opening area of the port 13, the minimum passage area A of the guide passage 33, or the cooperation between the scavenging port 13 and one of the first and second vanes 31 and 32 is determined. For example, when the passage area A is smaller than the opening area determined by the geometric shape of the scavenging port 13, the effective opening area is the passage area A, and when the passage area A is larger than the opening area, the effective opening area is The opening area or the passage area determined by the cooperation of the scavenging port 13 and one of the first and second vanes 31 and 32.

Then, when the second vane 32 is driven by the second drive ring 42 from the state described above and swings to the position indicated by the two-dot chain line where the guide angle θ2 becomes small, the swirl ratio is controlled to be small. At the same time, the effective opening area set by the passage area A is changed so as to increase. Further, from this state, when the first vane 31 is driven by the first drive ring 41 (see FIGS. 1 and 2) and swings to a position indicated by a three-dot chain line in which the guide angle θ1 is reduced, the swirl ratio is increased. Is further reduced, and the effective opening area is increased.
As described above, when the swing positions or guide angles θ1 and θ2 of the first and second vanes 31 and 32 are changed independently of each other, the swing positions or guide angles of all the vanes are uniformly changed. Compared to the above, the swirl ratio can be finely controlled, and the control accuracy of the swirl ratio can be improved.

7 and 8, as one form of the first and second vanes 31, 32, the passage of the guide passage 33 formed by the swing position of the first, second vane 31, 32 or the second vane 32. The form in which the effective opening area of the scavenging port 13 is set by the area A is shown.
Then, only the first vane 31 has the first drive ring 41 (FIGS. 1 and 2) with respect to the swinging position at which the first and second vanes 31 and 32 shown by solid lines in FIG. When the guide opening θ is swung so as to increase the guide angle θ1 and occupies the swinging position indicated by the two-dot chain line. Compared with the swirl ratio.

  Further, as shown in FIG. 8, in the form in which the first and second vanes 31 and 32 occupy the swing positions where the guide angles θ1 and θ2 are smaller than the swing position shown in FIG. The effective opening area set by the passage area determined by the cooperation of the port 13 and the second vane 32 becomes larger. Since the guide angles θ1 and θ2 of the first and second vanes 31 and 32 are reduced, the swirl ratio is reduced as compared with FIG. Also in this case, when only the first vane 31 is driven so as to increase the guide angle θ1 and occupies the position indicated by the two-dot chain line, The swirl ratio increases as compared to when the vane 31 is in the swing position indicated by the solid line.

  In this way, the effective opening area can be controlled by the position of the second vane 32, and the effective opening area is changed in a state where the effective opening area is maintained substantially constant by the second vanes 31 and 32. In addition, the swirl ratio can be controlled by the position of the first vane 31.

Next, operations and effects of the embodiment configured as described above will be described.
The airflow control device of the uniflow type two-stroke internal combustion engine E includes first and second vanes 31 and 32 that form a guide passage 33 that guides fresh air to the scavenging port 13 so that a swirl is generated in the cylinder chamber 14. In order to control the swirl ratio, the swing positions of the first and second vanes 31, 32 can be changed independently of each other, so that the first and second vanes 31, Since the swing position of 32 is controlled independently of each other, the swing position of the other vane is set to one swing position of one of the first and second vanes 31 and 32 constituting the vane mechanism. Since various changes can be made, a fine setting of the swirl ratio becomes possible. As a result, the swirl position of the first and second vanes 31 and 32 can be changed independently of each other, so that the swirl ratio can be finely controlled by the vane mechanism. In the internal combustion engine E, the swirl ratio can be controlled with high accuracy.

  The effective opening area of the scavenging port 13 is set by the passage area A of the guide passage 33, the effective opening area is controlled by the swing position of the second vane 32 or the guide angle θ2, and the effective opening area is substantially constant by the second vane 32. In this state, the swirl ratio is controlled by the swing position of the first vane 31, so that various swirl ratios can be set for the same effective opening area. In combination with the ratio, the swirl ratio can be finely controlled, and the optimum swirl ratio can be set in terms of engine performance such as combustibility or scavenging efficiency.

  The airflow control device includes first and second drive rings 41 and 42 for changing the positions of the first and second vanes 31 and 32, respectively. The first and second drive rings 41 and 42 are respectively arranged around the sleeve 8. Since the first and second drive rings 41 and 42 are arranged side by side in the cylinder axial direction by being arranged along the direction and arranged side by side in the cylinder axial direction, the first and second drive rings The drive mechanism composed of 41 and 42 is downsized in the radial direction.

  The first and second drive rings 41 and 42 are arranged at positions sandwiching the first and second vanes 31 and 32 in the cylinder axial direction, so that the first and second drive rings 41 and 42 Since the second vanes 31 and 32 are disposed in the spaces 46 and 47 in the cylinder axial direction with respect to the second vanes 31 and 32, the cylinder 3 or the sleeve 8 in the cylinder axial direction is driven by the drive mechanism including the first and second drive rings 41 and 42. Is prevented from becoming larger.

  The first and second vanes 31, 32 have hinge portions 31h, 32h supported by the sleeve 8 at the inner peripheral end portions 31i, 32i so as to be swingable. The inner peripheral end portions 31i, 32i are sleeves. 8, the inner peripheral end portions 31i and 32i of the first and second vanes 31 and 32 and the hinge portions 31h and 32h are accommodated in the concave portions 8e formed in the circumferential edges 8a and 8b of the scavenging port 13. Is housed in a recess 8e provided in the circumferential edge 8a, 8b of the scavenging port 13. For this reason, the inner peripheral end portions 31i and 32i do not serve as resistance of fresh air flowing through the scavenging port 13, which contributes to an increase in the swirl ratio.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
The engagement groove 48 or the engagement groove 49 may be inclined with respect to the radial direction as indicated by a three-dot chain line in FIG. 3, whereby the engagement pin 35 moves in the engagement groove 48. Since the frictional force when the engagement pin 36 moves in the engagement groove 49 is reduced, the driving force of the vanes 31 and 32 can be reduced, and the electric motors 51 and 52 can be downsized.
The pins formed integrally with the vanes 31 and 32 may be swingably supported by a support portion configured by holes provided in the circumferential edge portions 8a and 8b.
The internal combustion engine may be a single cylinder internal combustion engine or a compression ignition engine.
Although the internal combustion engine is used for a vehicle in the embodiment, it may be used for a ship propulsion device such as an outboard motor having a crankshaft oriented in the vertical direction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a uniflow type two-stroke internal combustion engine to which the present invention is applied, and is a schematic cross-sectional view in a plane that includes a cylinder axis and is orthogonal to a rotation center line of a crankshaft. FIG. 2 is a cross-sectional view of a main part of the internal combustion engine of FIG. 1, a part of which is a cross-sectional view taken along the line IIa of FIG. FIG. 3 is an enlarged view of a main part of FIG. 2. It is the IV-IV sectional view taken on the line of FIG. It is the VV sectional view taken on the line of FIG. It is a figure explaining one operation | movement of the vane of the airflow control apparatus of the internal combustion engine of FIG. 1, and is a figure similar to FIG. It is a figure corresponding to FIG. 6 explaining another operation | movement of the vane of the airflow control apparatus of the internal combustion engine of FIG. FIG. 7 is a view corresponding to FIG. 6 for explaining still another operation of the vane of the airflow control device for the internal combustion engine of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylinder block, 3 ... Cylinder, 8 ... Sleeve, 13 ... Scavenging port, 14 ... Cylinder chamber, 31, 32 ... Vane, 33 ... Guide passage, 41, 42 ... Drive ring, 46, 47 ... Space, 51, 52 ... Electric motor, 61,62 ... Worm gear,
L: Cylinder axis, A: Passage area.

Claims (5)

A cylinder provided with a scavenging port opened on an inner peripheral surface with which a reciprocating piston slides, and a flow of fresh air flowing from the scavenging port into a cylinder chamber formed by the cylinder are controlled in accordance with an engine operating state. In a uniflow type two-stroke internal combustion engine comprising an airflow control device,
The airflow control device includes a first vane and a second vane that form a guide passage for guiding fresh air to the scavenging port so that a swirl is generated in the cylinder chamber, and the first airflow control device controls the swirl ratio. A uniflow type two-stroke internal combustion engine characterized in that swing positions of the first vane and the second vane can be changed independently of each other.   The effective opening area of the scavenging port is set by the passage area of the guide passage, the effective opening area is controlled by the swing position of the second vane, and the effective opening area is maintained substantially constant by the second vane. 2. The uniflow type two-stroke internal combustion engine according to claim 1, wherein the swirl ratio is controlled by a swing position of the first vane in a state where   The airflow control device includes a first drive ring and a second drive ring that change the swing positions of the first vane and the second vane, respectively, and the first drive ring and the second drive ring are respectively 3. The uniflow type two-stroke internal combustion engine according to claim 1, wherein the uniflow type two-stroke internal combustion engine is arranged along a circumferential direction of the cylinder and arranged side by side in the cylinder axial direction.   4. The uniflow type two-stroke internal combustion engine according to claim 3, wherein the first drive ring and the second drive ring are arranged at positions sandwiching the first vane and the second vane in a cylinder axial direction.   Each of the first vane and the second vane has a hinge portion that is swingably supported by the cylinder at an inner peripheral end portion thereof, and each inner peripheral end portion is a peripheral portion of the scavenging port of the cylinder. The uniflow type two-stroke internal combustion engine according to any one of claims 1 to 4, wherein the uniflow type two-stroke internal combustion engine is accommodated in a recess formed in a directional edge.

Images