KR0130587B1 - The system having variable compression ratio in an internal combustion engine - Google Patents

Abstract

To continuously change the volume of the combustion chamber without changing the phase of the combustion chamber, this device comprises the cylinder head(10) in which the inhaler port(13) and the exhaustion port(14) are arranged, the second piston(20) which moves upward and downward, opposed to the first piston(4) inside the bore(11) of the cylinder head, thus when the first piston is in the top point, the upper face of the first piston and the volume of the combustion chamber, the lower face of the second piston form is able to be changed.

Description

Variable compression ratio device of internal combustion engine

1 is a partial cross-sectional view showing the configuration of a variable compression ratio device of the present invention.

2 is a cross-sectional view taken along line A-A of FIG.

3 is a cross-sectional view taken along line B-B of FIG. 1, showing a cam shaft moving means in a variable compression ratio apparatus according to the present invention.

4 is a partial cross-sectional view of FIG.

(a) is C-C cross section

(b) is D-D cross section

5 is a view showing a camshaft moving means for supporting and moving the camshaft from the rear

* Explanation of symbols for main parts of the drawings

2: cylinder block 4: first piston

6: combustion chamber 10: cylinder head

11: Bore 12: Gear accommodation portion

13 intake port 14: exhaust port

20: second piston 21: piston head

22: screw portion 23: slide portion

24: guide protrusion 25: intake hole

26: exhaust hole 30: drive gear

31: gear teeth 32: pinion gear

33: rotation axis 34: motor

40: guide cover 41: guide ball

42: guide rail 50: intake valve

51 exhaust valve 60 camshaft

61: cam 62: cam pulley

63: front support shaft 64,69,94: support

65: tension adjusting unit 66: rear support shaft

67,68: Hydraulic cylinder 70: Crank pulley

71: timing belt 80, 84, 92: bearing

90: idler pulley 91: central axis

93: horizontal movement shaft 95: sliding head

The present invention relates to a variable compression ratio apparatus of an internal combustion engine, and more particularly, in a four-stroke internal combustion engine, an opposite piston that is axially displaced against a reciprocating piston in a cylinder is installed, and in particular, without changing the shape of the combustion chamber. The present invention relates to a variable compression ratio apparatus of an internal combustion engine, which enables to finely change the volume and thus the compression ratio.

In general, in an internal combustion engine, the compression ratio is expressed as the ratio of the total cylinder volume to the combustion volume, and an engine that can set the combustion volume variably is generally referred to as a variable compression ratio engine. The variable compression ratio engine is widely used as an experimental engine for setting the optimum compression ratio factor that can achieve the best thermal efficiency without causing knocking by measuring the change in thermal efficiency, that is, the output of the internal combustion engine.

Conventional techniques for such a variable compression ratio engine are well known in US Pat. No. 4,046,50 (Mar. 7, 1989), US Pat. No. 48,340,31 (1989.8.29), US Pat.

No. 4,049,501 is provided with a second piston that independently reciprocates inside the first piston reciprocating the cylinder to change the combustion volume by hydraulically displacing the second piston. However, this requires a high level of technology since the hydraulic device must be installed inside the engine, and there is a problem such as concern about durability of the hydraulic retaining device, especially in a high temperature cylinder.

No. 4834031 has a separate auxiliary cylinder in communication with the combustion chamber in the cylinder head and an adjustment piston axially movable within the auxiliary cylinder on the side of the combustion chamber to change the combustion volume. However, this has a problem in that the shape of the combustion chamber is changed and the output value thereof cannot be affected by the pure compression ratio, so the reliability of the result is lowered. No. 5146897 has a bearing bore on one side of the connecting rod connecting the piston and the crankshaft. Eccentric sleeves are provided with fixing means for fixing the eccentric sleeves in the low compression ratio state and high compression ratio position, which is a technical difficulty in applying the fixing means and the fixed position of the eccentric sleeves in the high compression ratio state and low compression ratio The state can be fixed only in two positions, and even if a plurality of fixed positions are installed, there was a problem that it was not possible to change the minute and continuous combustion volume.

The present invention has been made in view of such a problem, and the combustion chamber is installed by axially displacing the second piston with a predetermined moving means by providing a second piston that is axially displaced against the reciprocating first piston in the cylinder. It is an object of the present invention to provide a variable compression ratio device of an internal combustion engine that enables the volume of the combustion chamber to be changed finely and continuously without changing the shape of the combustion chamber.

A variable compression ratio apparatus of an internal combustion engine of the present invention for achieving the above object comprises a cylinder in which the first piston reciprocates in an internal combustion engine including at least one cylinder and a first piston reciprocating in the cylinder. A cylinder head fixed to the upper end of the block and having a bore of coaxial / diameter with the first piston, and having an intake port and an exhaust port communicating with the bore; and a bore of the cylinder head. And a second piston that moves up and down to face the first piston therein, and a moving means for moving the second piston up and down, and the upper and lower surfaces of the first piston by vertical movement of the second piston. It is characterized in that it is configured to be able to change the volume of the combustion chamber formed into the space between the lower end of the second piston.

The moving means for axially moving the second piston includes a screw part formed in a predetermined length at one side outer diameter of the second piston, a drive gear screwed to the screw part and a predetermined number of gear teeth formed on the outer circumference thereof; The pinion gear is externally engaged with the gear teeth of the drive gear so that the second piston, which is screwed with the drive gear, is moved up and down by rotating the drive gear, and is connected to the rotation shaft extending from the pinion gear. It characterized in that it comprises a motor for rotating the gear in the forward and reverse directions.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a partial cross-sectional view showing a variable compression ratio device of the internal combustion engine of the present invention, in order to avoid the complexity of the drawing, the camshaft 60 omits a part of the rear thereof, and the lower portion of the front support shaft 63 and other configurations thereof. The connection with the elements is also omitted. Components associated with the anterior support shaft 63 are shown through FIG. 3.

FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1 and shows the guide portion 24 of the second piston 20 and the guide rail 42 of the guide cover 40 in detail.

3 is a cross-sectional view taken along the line B-B in FIG. 2, showing the cam shaft moving means associated with the cam shaft 60 and the front support shaft 63 of FIG. In the drawing, the up and down directions are directions in which the second piston 20 axially moves up and down.

4 is a cross-sectional view taken along line CC of FIG. 3 and shows a guide member 81 for guiding the movement of the front support shaft 63, and FIG. 4B is taken along the line DD of FIG. A guide member 83 for guiding the movement of the horizontal axis 93 as a cross-sectional view is shown.

FIG. 5 shows a rear support shaft 66 supporting the rear of the cam shaft 60 corresponding to the front support shaft 63 of FIG.

As shown in FIG. 1, the variable compression ratio apparatus of the internal combustion engine of the present invention includes a cylinder block 2 and a first piston 4 which vertically reciprocates a predetermined stroke within the cylinder block 2. In an internal combustion engine, the cylinder head 10 is seated on top of the cylinder block 2 in a conventional manner. The cylinder head 10 is formed with a bore 11 coaxial with the cylinder block 2 and a diameter thereof, and the bore 11 has a second piston facing the first piston 4. Piston head 21 of 20 is fitted to be installed so as to slide up and down. Thus, when the first piston 4 is at the top dead center, a space formed between the upper surface of the first piston 4 and the lower end of the piston head 21 of the second piston 20 becomes the combustion chamber 6.

Moving means for moving the second piston 20 up and down to change the volume of the combustion chamber 6 will be described.

A screw portion 22 having a predetermined length is formed as an upper outer diameter portion of the piston head 21 of the second piston 20. The screw portion 22 is screwed with a drive gear 30 that is rotatably received in the gear receiving portion 12 is formed in the upper portion of the cylinder head (10). A gear tooth 31 having a predetermined number of teeth is formed on the outer circumference of the drive gear 30, and the pinion gear 32 is externally engaged with the gear tooth 31. The rotary shaft 33 extending from the pinion gear 32 is connected to a motor 34 for rotating the pinion gear 32 in the forward and reverse directions. Its motor 34 is preferably to use a known stepping motor commonly used for the fine movement and easy control of the second piston (20), in this case the rotation of the stepping motor It is more preferable for the fine movement of the second piston 20 to use that the angle is set finer.

As described above, the drive gear 30 and the pinion gear 32 accommodated in the gear accommodation portion 12 of the cylinder head 10 are guided by a guide cover 40 fixed to the upper end of the cylinder head 10. It is closed from the top to allow rotation but is limited to not move up and down. In addition, a flat cylindrical slide portion 23 is extended to the upper portion of the screw portion 22 of the second piston 20 so as to be axially movable in the guide hole 41 formed through the guide cover 40. Is inserted. At this time, as shown in FIG. 2, the guide protrusions 24 protrude in left and right symmetry, and guide holes of the guide cover 40 on the outside of the slide portion 23 of the second piston 20. A guide rail 42 is provided at 41 so that the guide protrusion 24 is movably fitted to the guide rail 42. Here, the guide protrusion 24 and the guide rail 42 may be formed by selecting any one of the slide 23 and the guide cover 40 of the second piston 20. That is, the guide rail 42 may be provided on the slide part 23 and the guide protrusion 24 may be protruded on the guide cover 40, as opposed to the illustration.

As the moving means of the second piston 20 rotates the motor 34, the pinion gear 32 connected to the rotation shaft 33 rotates, and the drive gear 30 meshed with the pinion gear 32 also rotates. Rotate At this time, the drive gear 30 is screw-coupled with the screw portion 22 of the second piston 20 while being accommodated in the gear accommodation portion 12 of the cylinder head 10, the shaft through the guide cover 40 The second piston 20 is axially movable to the guide rail 42 of the guide cover 40 via the guide protrusion 24, but is rotatably fitted to the second piston 20. When the drive gear 30 rotates, the second piston 20 which is screwed thereto does not rotate but moves vertically so that the volume of the combustion chamber 6 is easily increased or decreased.

Next, the configuration of the intake and exhaust system to be applied as the second piston 20 moves up and down.

In the cylinder head 10, an intake port 13 and an exhaust port 14 communicate with the internal bore 11. In addition, both sides of the second piston 20 which slowly move in the bore 11 communicate with the intake and exhaust ports 13 and 14 so as to communicate with the combustion chamber 6, respectively. 26) is formed. At this time, since the second piston 20 moves up and down in the bore 11 of the cylinder head 10, the intake hole 25 and the exhaust hole 26 are moved by the movement of the second piston 20. The intake / exhaust holes 25 or the intake / exhaust ports 13 and 14 are blocked out of the piston head 21 of the second piston 20 to prevent intake and exhaust gas from leaking. 26) and the diameter of either of the intake and exhaust ports 13 and 14 should be small. As shown in FIG. 2, the diameters of the hollow holes 25 and the exhaust holes 26 formed in the second piston 20 are small. It is effective to make the second piston 20 compact.

Therefore, the maximum movement distance of the second piston 20 is limited within the range in which the intake hole 25 and the exhaust hole 26 do not leave the intake port 13 and the exhaust port 14. 13 and the exhaust port 14 are limited to the range not to escape the piston head 21 of the second piston (20).

In other words, the maximum length of the second piston 20 depends on the length of the piston head 21 of the second piston 20 and the sizes of the intake and exhaust holes 25 and 26 and the intake and exhaust ports 13 and 14. It is possible to increase the moving distance sufficiently.

In addition, the intake valve 50 and the exhaust valve 51 open and close the intake hole 25 and the exhaust hole 26 of the second piston 20 in communication with the combustion chamber 6 to control the intake air and the exhaust gas. The second piston 20 is vertically penetrated.

Therefore, the intake and exhaust valves 50 and 51 also move up and down integrally with the second piston 20, and the camshaft 60 and the cam 61 which operate the knee intake and exhaust valves 50 and 51 are also removed. The piston moves up and down by the amount of movement of the piston 20.

In FIG. 1, reference numeral 62 is a cam pulley which is integrally connected to the cam shaft 60 to rotate the cam shaft 60, and 63 is a front support shaft which rotatably supports the cam shaft 60 and moves up and down. 100 is a spark plug for igniting fuel in a gasoline engine.

Camshaft moving means for moving the camshaft 60 up and down is well illustrated in the attached drawings 3 to 5. FIG. 3 shows the cam pulley 62 side of the front view of the engine, that is, the cam pulley 62 in FIG. 1 in the direction in which the crank pulley 70 is located.

The cam pulley 62 is connected to the crank pulley 70 and the timing belt 71 to rotate. The cam pulley 62 is provided with a support portion 64 of the front support shaft 63 for supporting the cam shaft 60 in a rotatable manner on the cam shaft 60 at the rear, and the cam shaft 60 and the front finger. A bearing 80 is interposed between the support portions 64 of the support shaft 63 to keep the cam shaft 60 rotatable.

The lower end of the front support shaft 63 is connected to the hydraulic cylinder 67 is moved in the direction of the up, down arrow in accordance with the operation of the hydraulic cylinder (67). The hydraulic cylinder 67 is controlled to operate the same distance as the up, down movement amount of the second piston (20).

As the camshaft 60 and the cam pulley 62 move up and down in this manner, the tension of the timing belt 71 connected to the crank pulley 70 should be kept constant.

It forms a triangular tension adjusting portion 65 at the lower end of the front support shaft 63, the idle pulley 90 is moved horizontally in accordance with the up and down movement of the inclined both sides (65a) of the tension adjusting portion (65) It is achieved by installing symmetrically left and right. The central axis 91 of the idle pulley 90 is rotatably held by one support portion 94 of the horizontal moving shaft 93 with the bearing 92 interposed therebetween. One sliding head 95 of the horizontal moving shaft 93 is installed in surface contact with both sides (65a) of the triangle of the front support shaft (63).

Accordingly, when the tension adjusting part 65 is moved by the front support shaft 63 by the up and down movement (up and down arrow directions), the horizontal moving shaft is in contact with both sides 65a of the tension adjusting part 65. The camshaft 60, the cam pulley 62 and the front of the sliding head 95 of the 93 are pushed outwards or naturally moved inwards (in the direction of the left and right arrows) by the tension of the timing belt 71. The idle pulley 90 is horizontally moved as the prevention shaft 63 moves up and down, thereby compensating for the moving amount of the cam pulley 62 to maintain the tension of the timing belt 71 at all times.

On the other hand, at least one guide member (81, 82) fixed to the engine to guide the vertical movement of the front support shaft (63) at a predetermined interval on the axis of the front support shaft (63), It is preferable to induce stable operation by installing guide members 83 fixed to the engine to guide the horizontal movement of the horizontal movement shaft 93 to the horizontal movement shaft 93 on the left and right sides, respectively.

As shown in (a) and (b) of FIG. 4, the eyepiece members 81, 82, and 83 are lower blocks 81a for supporting lower portions of the front support shaft 63 and the horizontal movement shaft 93, respectively. 83a) and upper blocks 81b and 83b fixed to the lower blocks 81a and 81b to cover the upper portion thereof.

The fifth is a rear support shaft 66 for rotatably supporting the rear portion of the cam shaft 60 in parallel with the front support shaft 63, and to move up and down. Similarly to the front support shaft 63, the rear support shaft 66 also maintains the cam shaft 60 rotatably via the bearing 84, and the other side thereof is the hydraulic cylinder 68. ) Is moved up and down in accordance with the operation of the hydraulic cylinder (68).

The working distance of the hydraulic cylinder 68 is controlled to be the same as the moving distance of the hydraulic cylinder 67 for moving the front support shaft (63). In addition, it is guided to be movable through the guide of the guide member 85 of the rear support shaft (66). This guide member 85 has the same configuration as the guide member 81 of FIG.

Therefore, the second piston 20 is moved up and down by rotating the pinion gear 32 and the drive gear 30 by driving the motor 34 to change the volume of the combustion chamber 6, and at the same time the hydraulic pressure The cam shaft 60 is moved by operating the cylinders 67 and 68 up and down by the same amount.

Here, the second piston 20 can be moved up and down finely by the screw coupling of the drive gear 30 and the second piston 20.

Thus, the variable compression ratio apparatus of the internal combustion engine according to the present invention is installed in the combustion chamber by installing a second piston 20 which is axially displaced in the axial direction opposite to the first piston 4 reciprocating inside the cylinder block (2). By changing the volume of, it is possible to change the volume of the combustion chamber finely and continuously without changing the shape of the combustion chamber, and when using it as an experimental engine, it is possible to detect only the influence of the output by the pure compression ratio factor. It is very reliable.

Claims (8)

In an internal combustion engine comprising at least one cylinder and a first piston (4) reciprocating in the cylinder, the first piston (4) is seated and fixed to an upper end of the cylinder block (2) reciprocating, A cylinder head having an intake port 13 and an exhaust port 14 communicating with the bore 11 is formed perpendicularly to the center of the first piston 4 and the bore 11 of coaxial / diameter diameter. 10, the second piston 20 which moves up and down in the bore 11 of the cylinder head 10 to face the first piston 4, and the second piston 20 Combustion chamber (6) is formed as a space between the upper surface of the first piston (4) and the lower end of the second piston (20) by moving the upper and lower of the second piston 20, including a moving means for moving downward Variable compression ratio device of the internal combustion engine, characterized in that configured to change the volume. According to claim 1, The moving means for axially moving the second piston 20, the screw portion 22 and the screw portion 22 formed in a predetermined length on the outer diameter of one side of the second piston (20) And a second piston that is screwed to the drive gear 30 by rotating the drive gear 30 and the drive gear 30 having a predetermined number of gear teeth 31 on the outer circumference thereof. The pinion is connected to a pinion gear 32 externally engaged with the gear tooth 31 of the drive gear 30 so that 20 is moved up and down, and a rotation shaft 33 extending from the pinion gear 32. A variable compression ratio device for an internal combustion engine, characterized by comprising a motor (34) for rotating the gear (32) in the forward and reverse directions. According to claim 2, wherein the drive gear 30 and the pinion gear 32 is manual to the gear receiving portion 12 formed on the upper end of the cylinder head 10, the upper end of the cylinder head 10 A guide cover 40 is mounted and fixed to block the upper surfaces of the drive gear 30 and the pinion gear 32 to restrict movement in the up and down axial directions, and the screw portion 22 of the second piston 20 is fixed. The upper portion is a slide portion 23 is formed to be axially movable in the guide hole 41 is formed through the guide cover 40 is extended, the second piston 20 to prevent rotation and A guide protrusion 24 protrudes from one of the slide 23 and the guide hole 41 to guide the axial movement, and a guide slidably fits with the guide protrusion 24. Variable of internal combustion engine characterized by the fact that rail 42 is provided Compression ratio device. The intake air of claim 1, wherein the second piston 20 communicates with the combustion chamber 6 by communicating with the intake / exhaust ports 13 and 14 of the cylinder head 10 on both sides of the piston head 21. And a ball 25 and an exhaust hole 26, which are installed through the second piston 20 to vertically open and close the intake hole 25 and the exhaust hole 26 to control the intake air and the exhaust gas. A variable compression ratio device for an internal combustion engine, comprising an intake valve (50) and an exhaust valve (51). The method of claim 1 or 4, wherein the intake and exhaust holes 25 and 26 and the intake and exhaust ports 13 and 14 at the maximum stroke of the second piston 20 are prevented from being blocked or deviated from each other. One of the intake and exhaust ports 13 and 14 and the intake and exhaust holes 25 and 26 corresponding to the upper and lower strokes of the second piston 20 is smaller than the other one. Variable compression ratio apparatus of an internal combustion engine. The cam pulley 62, the cam shaft 60, and the cam (60) connected to the crank pulley 70 and the timing belt 71 of the engine so as to operate the intake / exhaust valves 50 and 51. And a camshaft 60 to move the camshaft 60, which is integrally formed with the cam 61 and the cam pulley 62, to move up and down in correspondence with the up and down movement amount of the second piston 20. A variable compression ratio device for an internal combustion engine, characterized by comprising a cam shaft moving means for supporting and moving at least two places of (60). According to claim 6, The camshaft moving means is a front support shaft (63) with a bearing (80) interposed on one side support portion (64) so as to rotatably support the cam shaft (60) from the front, and the front support shaft (63) Is connected to the other side of the hydraulic cylinder (67) for moving the front support shaft (63) up and down, and a bearing (84) on one side support (69) to rotatably support the cam shaft (60) from the rear. Variable of the internal combustion engine comprising an interposed rear support shaft 66 and a hydraulic cylinder 68 connected to the other side of the rear prevention support shaft 66 to move the rear support shaft 66 up and down. Compression ratio device. The timing of connecting the crank pulley 70 and the cam pulley 62 according to the upper and lower movements of the cam shaft 60, the cam pulley 62, and the front support shaft 63 according to claim 6 or 7. A triangular tension adjusting part 65 formed at one end of the front support shaft 63 and the left and right sides of the front support shaft 63 are symmetrically installed to keep the tension of the belt 71 constant. An idle pulley 90 through which 71 passes through, and one side rotates the central axis 91 of the idle pulley 90 through its support 94 and a bearing 92 interposed therebetween. It is accommodated and the other side is in contact with one side (65a) of the tension adjustment unit 65 is a horizontal movement shaft 93 is formed with a sliding head 95 to move horizontally in accordance with the up and down movement of the tension adjustment unit 65. Variable compression ratio device of an internal combustion engine comprising a.