KR102053100B1 - Variable compression ratio devcie - Google Patents

Abstract

The present invention provides a variable compression ratio device including: a piston lifting in an engine cylinder; a connecting rod connected to the piston; a rotating rod connected to the connecting rod and rotatable about a fixed point; a top dead point variable device which is connected to the connecting rod and adjusts a piston top dead point by adjusting the position of the piston; a crank shaft positioned under the connecting rod and rotating around an axis while making a rotational track; and a link device having one end rotationally connected to one end of the rotating rod opposite to the connecting rod and a first hinge shaft, and the other end rotationally connected to the crank shaft and a second hinge shaft.

Description

Variable Compression Ratio Unit {VARIABLE COMPRESSION RATIO DEVCIE}

The present invention relates to a variable compression ratio device for varying the compression ratio by varying the top dead center of the piston making the lifting motion in the engine cylinder.

Recently, due to the rise in oil prices, interest in improving fuel efficiency of vehicles is increasing, and research and development of technologies that help drivers drive to improve fuel efficiency are being actively conducted. The variable compression ratio engine is one of them. In the case of internal combustion engines, as the compression ratio increases due to the theoretical air-fuel ratio, the energy efficiency increases to reduce the fuel consumption rate and improve the maximum power.

However, the variable compression ratio engine has an advantage in that it can be operated by varying the compression ratio by changing the piston lift amount, that is, top dead center of the engine. It can operate at a high compression ratio only in a variablely required operating region, not a fixed compression ratio, thereby reducing fuel consumption and preventing knocking. In variable compression ratio engine technology, it is important to effectively control the piston lift to achieve a high compression ratio. To this end, high pressure ratios are realized by changing the inside of cylinders or by changing various structures such as pistons, connecting rods, and crankshafts.

Therefore, it is urgent to develop a variable compression ratio engine having an efficient structure.

Republic of Korea Patent Publication No. 10-1996-0041660 (published Dec. 19, 1996)

In order to solve the above problem, the present invention is to provide a variable compression ratio device that can increase the engine output by varying the compression ratio through the top dead center variable.

The present invention is a piston for lifting in the engine cylinder; A connecting rod connected to the piston; A rotating rod connected to the connecting rod and rotatable about a fixed point; A top dead center variable device configured to be connected to the connecting rod to change a piston top dead center by adjusting a position of the piston; A crank shaft positioned under the connecting rod and rotating the shaft while drawing a rotational track; And a link device having one end rotatably connected to one end of the rotary rod opposite the connecting rod and the first hinge shaft, and the other end rotatably connected to the crank shaft and the second hinge shaft. It provides a variable compression ratio device comprising a.

In addition, the top dead center variable device is connected to the rotating rod, the motor having a screw portion on the outer periphery of the rod; And a guide screw coupled to the screw part of the motor to enable sliding movement along the longitudinal direction of the rotating rod by a rotation operation of the rod provided in the motor, and to be rotatable by the connecting rod and the hinge pin. can do.

The guide may include an upper portion including a first hole coupled to the hinge pin and a second hole positioned below the first hole and coupled to a threaded portion of the rod; And a lower portion coupled to the guide insertion groove provided in the rotation rod and moving along the guide insertion groove.

The link device may further include a first link having one end rotatably connected to one end of the rotating rod opposite to the connecting rod and the first hinge shaft, and configured to linearly move up and down; And a second link having one end rotatably connected by the crankshaft and the second hinge shaft and the other end rotatably connected by the other end and the third hinge shaft of the first link. .

In addition, the first link may be a linear reciprocating motion up and down while being supported by a guide frame positioned below the rotating rod.

In addition, the top dead center variable apparatus may be located at the connecting rod side and the link apparatus may be positioned at the crank shaft side based on the fixed point.

The present invention, by adjusting the top dead center of the piston to control the output of the engine by lowering or increasing the compression ratio according to the degree of load applied to the drive can maximize the engine efficiency.

In addition, by varying the top dead center, the compression ratio can be varied, which can increase the power and significantly reduce carbon monoxide and nitrogen oxide emissions.

1 is a view showing a state in which the piston is located at the bottom dead center according to an embodiment of the present invention.
2 is a view showing a state in which the piston is located in the interval between the bottom dead center and the top dead center according to an embodiment of the present invention.
3 is a view showing a state where the piston is located in the top dead center according to an embodiment of the present invention.
4 is a diagram illustrating a top dead center variable process according to an exemplary embodiment of the present invention.
5 is a cross-sectional view taken along the line AA of FIG.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible, even if shown on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the following will describe a preferred embodiment of the present invention, but the technical idea of the present invention is not limited thereto and may be variously modified and modified by those skilled in the art.

In general, the engine rotates as the piston moves up and down. At this time, the top dead point (TDP: Top Dead Point) refers to the point where the piston is located at the top of the upstroke in the cylinder. Bottom Dead Point (BDP) is the point where the piston is located at the bottom of the downstroke in the cylinder.

The present invention is to provide a variable compression ratio device that can improve the engine efficiency at a high compression ratio by varying the top dead center of the piston only in a variable operating area, not a predetermined compression ratio.

1 is a view showing a state in which the piston according to an embodiment of the present invention located at the bottom dead center, Figure 2 is a state in which the piston is located in the interval between the bottom dead center and the top dead center in accordance with a preferred embodiment of the present invention. 3 is a view showing a state in which the piston is located in the top dead center according to an embodiment of the present invention.

The present invention is a piston 20 for lifting in the combustion chamber 11 of the engine cylinder 10, the connecting rod 30 is connected to the piston 20, the rotating rod 40 is connected to the connecting rod 30 Is connected to the rotating rod 40, the top dead center variable device 50 for varying the position of the piston top dead center, the crank shaft 60 and the crank shaft 60 to change the lifting movement of the piston 20 to the rotational movement and rotation Link device 70 for connecting the rod 40 is included.

The piston 20, the connecting rod 30 and the crankshaft 60 may utilize various configurations of known configurations in the present invention.

The rotating rod 40 may rotate about the fixing point 41. The fixing point 41 is located between both ends at a distance from both ends of the rotating rod 40. The fixing point 41 may be biased to be closer to the linking device 70 side than the connecting rod 30 side.

Rotating rod 40 may be provided with a variable device 50 for varying the piston top dead center. One end of the rotary rod 40 is connected to the linkage 70 and the other end is connected to the connecting rod 30.

The crankshaft 60 is located below the connecting rod 30. The crankshaft 60 makes axial rotation while drawing the rotary track 61. The crankshaft 60 changes the lifting movement of the piston 20 to the rotational movement.

The rotary rod 40 and the crankshaft 60 are connected by the link device 70, and the lifting motion of the piston 20 is transmitted to the crankshaft 60. The linkage 70 includes a first link 71 and a second link 72.

3 is a view showing a state where the piston is located in the top dead center according to an embodiment of the present invention.

The first link 71 is rotated about the first hinge shaft 81 by being connected to one end of the rotating rod 40 and the first hinge shaft 81 at one end thereof opposite the connecting rod 30. It is possible. The first link 71 penetrates the guide frame 90 and performs a linear reciprocating motion in a supported state on the guide frame 90.

The second link 72 connects the first link 71 and the crankshaft 60. One end of the second link 72 is connected by the crank shaft 60 and the second hinge shaft 82 to be rotatable about the second hinge shaft 82. The other end of the second link 72 is connected to the other end of the first link 71 by the third hinge axis 83, and is rotatable about the third hinge axis 83.

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

The top dead center variable device 50 includes a motor 51 and a guide 52. The motor 51 is connected with the rotary rod 40. The motor 51 may be positioned to be biased toward the connecting rod 30 based on the fixing point 41. The thread part 512 is provided in the outer periphery of the rod 511 of the motor 51.

The guide 52 is connected to the connecting rod 30 and the rotating rod 40 at the same time. The guide 52 is screwed to the threaded portion 512 of the motor 51. The guide 52 moves along the threaded portion 512 during the rotation operation of the rod 511 of the motor 51 and slides along the longitudinal direction of the rotary rod 40.

The guide 52 includes an upper portion 521 connected by the connecting rod 30 and the hinge pin 520, and a lower portion 522 connected to the rotation rod 40.

The upper portion 521 of the guide 52 is coupled to the first hole 521a to which the hinge pin 520 connecting the guide 52 and the connecting rod 30 is coupled, and the screw portion 512 of the motor 51. The second hole 521b is provided. The first hole 521a may be a through hole and the second hole 521b may be a screw hole corresponding to the threaded portion 512. The lower portion of the connecting rod 30 is rotatably connected to the guide 52 by the hinge pin 520.

The lower portion 522 of the guide 52 is inserted into the guide insertion groove 42 provided in the rotary rod 40 to slide along the guide insertion groove 42. The lower portion 522 of the guide 52 may be formed to have a width wider than the width of the upper portion 521. The shape of the guide 52 is not limited. For example, the guide 52 may be shaped like "┻".

The following describes the operation of the piston.

As shown in FIG. 1, when the piston 20 is located at the bottom dead center BDP during the down stroke in the cylinder 10, one end of the rotating rod 40 is positioned above the fixing point 41 and the other side of the rotating rod 40. The end is located below the anchor point 41. At this time, the rotation angle of the crankshaft 60 is 0 degrees.

As shown in FIG. 2, when the piston 20 is positioned between the top dead center and the bottom dead center during the ascending stroke in the cylinder 10, the rotary rod 40 pushes the connecting rod 30 upward while being approximately horizontal and thus the piston ( 20) rises. At this time, the connecting rod 30 and the guide 52 form a straight line in a substantially vertical direction, and the crank shaft 60 rotates about 90 degrees.

When the piston 20 is located at the top dead center (TDP) during the upstroke in the cylinder 10 as shown in FIG. 3, one end of the rotating rod 40 is inclined downward than the fixing point 41, and the other end is raised. While pushing up the connecting rod (30). The other end of the rotating rod 40 is located above the fixing point 41. At this time, the connecting rod 30 and the guide 52 form a straight line in a substantially vertical direction, and the crank shaft 60 rotates about 180 degrees.

The following describes the top dead center variable process of the piston by the top dead center variable device.

In the state where the piston is located at the top dead center (TDP) as shown in FIG. 4 (a), the position of the top dead center (TDP) may be varied as shown in FIG.

As shown in FIG. 4B, when the rod 511 is rotated by the driving of the motor 51, the guide 52, which is screwed with the threaded portion 512, ends along the guide insertion groove 42 and the threaded portion 512. Go to 513. When the guide 52 moves to the rod end 513 to the other end of the rotary rod 40, the connecting rod 30 moves up and pushes the piston 20. This causes the top dead center of the piston 20 to rise up.

The distance between the guide 52 and the fixed point 41 about the fixed point 41 is a variable length. In contrast, the distance between the fixed point 41 and the first hinge shaft 81 is a fixed length. As the guide 52 moves toward the rod end 513, the connecting rod 30 rises upward and the top dead center rises because the piston 20 also moves upward.

When the top dead center (TDP) of the piston 20 rises upward, the compression ratio increases as the volume of the combustion chamber 11 in the engine cylinder 10 decreases.

The combustion chamber is a space surrounded by the piston head and the intake and exhaust valves and the like when the piston is at the top dead center. The cylinder volume is the volume of the combustion chamber plus the displacement.

The mixer sucked into the cylinder is compressed from the compression stroke to the combustion chamber volume, and the compression ratio is the cylinder volume divided by the combustion chamber volume.

The higher the top dead center, the higher the compression ratio, and the higher the compression ratio, the stronger the mixer is, the higher the temperature of the mixer is. In addition, since the volume of the combustion gas expands in the combustion stroke as it is compressed, the exhaust temperature does not become too high and fuel economy is also improved.

As described above, the present invention can provide an engine capable of exhibiting fuel efficiency, high power and torque. The fixed compression ratio of the existing engine is one compression ratio determined in consideration of various operating conditions, while the present invention can vary the compression ratio by varying the top dead center according to various operating conditions, thereby increasing the power and exhausting carbon monoxide and nitrogen oxides. Can also be significantly reduced.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

10: cylinder
11: combustion chamber
20: piston
30: connecting rod
40: rotating rod
41: fixed point
42: guide insertion groove
50: top dead center variable device
51: motor
52: guide
60: crankshaft
61: rotational track
70 link device
71: the first link
72: second link
81: first hinge axis
82: second hinge axis
83: third hinge axis
90: guide frame
511: load
512: screw part
513: end of rod
520 hinge pin
521: upper
521a: first hole
521b: second hole
522: lower

Claims (6)

A piston for lifting in an engine cylinder;
A connecting rod connected to the piston;
A rotating rod connected to the connecting rod and rotatable about a fixed point;
A top dead center variable device configured to be connected to the connecting rod to change a piston top dead center by adjusting a position of the piston;
A crank shaft positioned below the connecting rod and rotating the shaft while drawing a rotational track; And
A link device having one end rotatably connected to one end of the rotating rod opposite the connecting rod and the first hinge shaft, and the other end rotatably connected to the crank shaft and the second hinge shaft;
Including,
The top dead center variable device,
A motor connected to the rotary rod, the screw having a threaded portion at a rod outer periphery; And
A guide screwed to the threaded portion of the motor to enable sliding movement along the longitudinal direction of the rotary rod by a rotation operation of the rod provided in the motor and to be rotatable by the connecting rod and the hinge pin;
Variable compression ratio device comprising a. delete The method of claim 1,
The guide,
An upper part including a first hole to which the hinge pin is coupled and a second hole to be disposed below the first hole and to be coupled to a screw part of the rod; And
A lower portion coupled to the guide insertion groove provided in the rotation rod and moving along the guide insertion groove;
Variable compression ratio device comprising a. The method of claim 1,
The link device,
A first link of which one end is rotatably connected to one end of the rotating rod opposite to the connecting rod and the first hinge shaft, and linearly reciprocates upward and downward; And
A second link whose one end is rotatably connected by the crankshaft and the second hinge axis and the other end is rotatably connected by the other end and the third hinge axis of the first link;
Variable compression ratio device comprising a. The method of claim 4, wherein
The first link is,
Variable compression ratio device characterized in that the linear reciprocating movement up and down in a state supported by the guide frame positioned below the rotating rod. The method of claim 1,
The top dead center variable device is located on the connecting rod side and the link device is located on the crankshaft side based on the fixed point.

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