KR101500386B1 - Variable compression ratio device - Google Patents

Abstract

The present invention relates to a variable compression ratio device, which simultaneously implements a change of a compression ratio and recirculation of exhaust gas. According to an embodiment of the present invention, a variable compression ratio device that changes a top dead point of a piston provided in an engine according to driving states of the engine, includes: a lower piston provided to reciprocate in a cylinder of the engine, and connected to a connecting rod to rotate a crank shaft by the reciprocating motion; a working room formed that is a space formed on a relatively upper side than a portion of the lower piston connected to the connecting rod; an upper piston disposed on a relatively upper side than the lower piston, and having one portion inserted into the working room; a push plate formed on a portion of the upper piston to partition the working room vertically; a hydraulic chamber that is a lower space of the partitioned working room; an elastic member provided on an upper space of the partitioned working room to push the push plate downwardly; a hydraulic supply unit configured to supply hydraulic pressure to the hydraulic chamber such that the push plate can be pushed upwardly and selectively by the hydraulic pressure; and a hydraulic supply circuit configured to connect the hydraulic supply unit and the hydraulic chamber such that hydraulic pressure can be supplied from the hydraulic supply unit from the hydraulic chamber. A fluid that is supplied to the hydraulic chamber to form hydraulic pressure may be gas.

Description

[0001] VARIABLE COMPRESSION RATIO DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a variable compressor apparatus, and more particularly, to a variable compressor apparatus that simultaneously implements a change in compression ratio and recirculation of exhaust gas.

Generally, the heat efficiency of a heat engine is increased when the compression ratio is high. Here, the compression ratio is a ratio of the volume of gas compressed into the cylinder by the piston and expressed as 'cylinder volume / combustion chamber volume at top dead center of piston'. That is, as the top dead center of the piston increases, the compression ratio increases.

In the case of a spark ignition engine, the thermal efficiency may be increased by advancing the ignition timing. However, considering the abnormal combustion, there may be a limit in advancing the ignition timing. Therefore, a variable compression ratio (VCR) device for improving the heat efficiency of the heat engine is required.

The variable compression ratio device is a device that changes the compression ratio of the mixer according to the operating state of the engine. This variable compression ratio device improves the fuel economy by increasing the compression ratio of the mixer in a low load condition of the engine and supplies the maximum mixer in the high load condition of the engine and at the same time lowers the compression ratio of the mixer Thereby preventing the occurrence of knocking and improving the engine output.

However, in order to implement the conventional variable compression ratio apparatus, many mechanical components are required, and the configuration becomes complicated. Further, there is a problem that the fuel consumption may be deteriorated when a motor or the like having electric power as a power source is used to drive mechanical components. Further, the power transmission of the motor is required to have a relatively large driving torque as compared with other gear engagement, which limits the capacity of the motor to be small. Thus, the overall weight of the vehicle may increase and the fuel economy may deteriorate. Furthermore, if the connection relation of the mechanical components becomes complicated, it is not easy to secure the quick response of the variable compression ratio device.

On the other hand, nitrous oxide (NOx) contained in the exhaust gas is regulated as a main air pollutant, and a lot of studies are being conducted to reduce NOx emissions.

An exhaust gas recirculation (EGR) system is a system mounted on a vehicle for the reduction of harmful exhaust gases including NOx and the like. Generally, NOx is increased when the proportion of air in the mixer is high and the combustion is good. Therefore, the exhaust gas recirculation system is a system that mixes a part of the exhaust gas discharged from the engine (for example, 5 to 20%) back into the mixer to reduce the amount of oxygen in the mixer and obstruct combustion, thereby suppressing the generation of NOx.

However, in order to implement the exhaust gas recirculation system, a complicated configuration is required for the engine and the peripheral equipment of the engine, and the production cost of the automobile increases and the productivity can be reduced.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a variable compressor device that simultaneously realizes a change in compression ratio and recirculation of exhaust gas.

Another object of the present invention is to provide a variable compression ratio device which is simple in configuration and in which responsiveness can be ensured.

Furthermore, another object is to provide a variable compression ratio apparatus which simplifies the system for recirculation of exhaust gas.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a variable compression ratio apparatus for varying a top dead center of a piston provided in an engine according to an engine operating state, A lower piston connected to the connecting rod to rotate the crankshaft by reciprocating motion; An operating chamber which is a space formed in the lower piston relatively above the portion connected to the connecting rod; An upper piston disposed relatively above the lower piston and partially inserted into the working chamber; A push plate formed on a portion of the upper piston to partition the operating chamber vertically; A hydraulic chamber which is a lower space of the partitioned working chamber; An elastic member provided in an upper space of the partitioned working chamber to push the push plate downward; A hydraulic pressure supply unit for supplying hydraulic pressure to the hydraulic chamber such that the push plate is selectively pushed upward by hydraulic pressure; And a hydraulic pressure supply circuit that connects the hydraulic pressure supply unit and the hydraulic chamber so that the hydraulic pressure is supplied to the hydraulic pressure chamber from the hydraulic pressure supply unit. . ≪ / RTI >

The fluid supplied to the hydraulic chamber and forming the hydraulic pressure may be a gas.

The gas supplied to the hydraulic chamber and forming the hydraulic pressure may be exhaust gas.

Wherein the hydraulic pressure supply portion includes a compressor portion where a compressed exhaust gas is located at a compressor side of the turbocharger; A high pressure pump which receives exhaust gas from the compressor unit and pumps the exhaust gas to transfer high pressure exhaust gas to an oil pressure supply circuit; . ≪ / RTI >

The high pressure exhaust gas delivered to the hydraulic pressure supply circuit may be supplied to the hydraulic chamber.

The variable compression ratio device includes an exhaust gas recirculation passage formed in the upper piston to communicate the hydraulic chamber and the combustion chamber; And a check valve disposed on the exhaust gas recirculation passage for selectively opening and closing the exhaust gas recirculation passage; As shown in FIG.

When the check valve is opened, the exhaust gas can be recirculated from the hydraulic chamber to the combustion chamber.

The check valve is opened naturally when the hydraulic pressure difference between the hydraulic chamber and the combustion chamber is equal to or greater than a set value, and can be closed naturally when the hydraulic pressure difference between the hydraulic chamber and the combustion chamber is less than a set value.

Wherein the hydraulic pressure supply unit comprises: a turbine section where exhaust gas is located at a front end side of an exhaust turbine of the turbocharger; An exhaust gas recirculation cooler for receiving exhaust gas from the turbine portion and cooling the exhaust gas; A high pressure pump which receives exhaust gas from the exhaust gas recirculation cooler and pumps the exhaust gas to transfer the high pressure exhaust gas to the hydraulic pressure supply circuit; . ≪ / RTI >

The high pressure exhaust gas delivered to the hydraulic pressure supply circuit may be supplied to the hydraulic chamber.

The variable compression ratio device includes an exhaust gas recirculation passage formed in the upper piston to communicate the hydraulic chamber and the combustion chamber; And a check valve disposed on the exhaust gas recirculation passage for selectively opening and closing the exhaust gas recirculation passage; As shown in FIG.

When the check valve is opened, the exhaust gas can be recirculated from the hydraulic chamber to the combustion chamber.

The check valve is opened naturally when the hydraulic pressure difference between the hydraulic chamber and the combustion chamber is equal to or greater than a set value, and can be closed naturally when the hydraulic pressure difference between the hydraulic chamber and the combustion chamber is less than a set value.

When the hydraulic pressure in the hydraulic chamber is higher than a predetermined value, the upper piston rises with respect to the lower piston, and when the hydraulic pressure is not supplied to the hydraulic chamber, The piston may be retracted into contact with the lower piston.

The hydraulic pressure supply circuit includes: a first hydraulic line formed in the cylinder block and having one end connected to the hydraulic pressure supply; A second hydraulic line formed on the crankshaft and having one end communicated with the other end of the first hydraulic line; A third hydraulic line formed in the connecting rod and having one end communicated with the other end of the second hydraulic line; And a fourth hydraulic line formed on the lower piston, one end of the fourth hydraulic line communicating with the other end of the third hydraulic line, and the other end communicating with the hydraulic chamber; . ≪ / RTI >

The fluid supplied from the hydraulic pressure supply unit may be supplied to the hydraulic chamber sequentially through the first hydraulic line, the second hydraulic line, the third hydraulic line, and the fourth hydraulic line sequentially.

Wherein the sealing member is provided at a portion to which the hydraulic pressure supply circuits are respectively connected and the sealing member provided at each of the two components facing the hydraulic pressure supply circuit is connected to the sealing member, At least one of the sealing members may protrude from a surface that the two components face.

As described above, according to the embodiment of the present invention, by using the hydraulic pressure for the operation of changing the top dead center of the piston, the configuration is simplified, the responsiveness of changing the compression ratio is improved, and the overall weight can be minimized. Therefore, the fuel consumption of the engine can be improved.

Further, by using the exhaust gas to form the hydraulic pressure for performing the compression ratio change and supplying the exhaust gas used for the compression ratio change to the combustion chamber, the compression ratio change and the recirculation of the exhaust gas can be realized at the same time. Can be simplified.

1 is a configuration diagram of a variable compression ratio apparatus according to an embodiment of the present invention.
2 is an operational view of a variable compression ratio apparatus according to an embodiment of the present invention.
3 is a view schematically showing a hydraulic pressure supply circuit according to an embodiment of the present invention.
4 is a block diagram of a hydraulic supply according to one embodiment of the present invention.
5 is a block diagram of a hydraulic supply according to another embodiment of the present invention.
6 is a block diagram of a hydraulic supply according to another embodiment of the present invention.
7 is a view showing an exhaust gas recirculation passage according to an embodiment of the present invention.

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

1 is a configuration diagram of a variable compression ratio apparatus according to an embodiment of the present invention.

1, the variable compression ratio apparatus according to the embodiment of the present invention includes a lower piston 10, an upper piston 20, an elastic member 26, a hydraulic pressure supply circuit 40, and a hydraulic pressure supply unit 70, . The lower piston 10, the upper piston 20 and the elastic member 26 constitute a piston P which is reciprocatably movable in the cylinder C of the engine.

The lower piston 10 is connected to the connecting rod 30 to rotate the crankshaft 50 by reciprocating movement in the cylinder C (see FIG. 3). The lower piston 10 includes a pin hole 12, a working chamber 14, a hydraulic chamber 16, and a rod insertion hole 18.

The connecting rod 30 receives the combustion force from the lower piston 10 and transmits the combustion force to the crankshaft 50 (see FIG. 3). One end of the connecting rod 30 is rotatably connected to the lower piston 10 by a piston pin 35 and the other end of the connecting rod 30 is connected to the crankshaft 50). One end of the connecting rod 30 connected to the piston P is generally referred to as a small end portion 32 and the other end of the connecting rod 30 connected to the crankshaft 50 is connected to the large end portion 34 ).

The pin hole 12 is a hole into which the piston pin 35 is inserted. That is, the piston pin 35 is arranged to pass through the small end 32 of the connecting rod 30 and the pin hole 12, so that the connecting rod 30 and the lower piston 10 are connected.

Since the connection of the connecting rod 30 and the piston P by the piston pin 35 is obvious to those skilled in the art (hereinafter, those skilled in the art), detailed description thereof will be omitted.

The operating chamber 14 is a space formed at the upper portion of the lower piston 10 relative to a portion where the connecting rod 30 and the lower piston 10 are connected.

The hydraulic chamber (16) is formed so that hydraulic pressure can be supplied to a part of the operation chamber (14).

The rod insertion hole 18 is a hole formed to pass from the upper end of the lower piston 10 to the operation chamber 14.

A part of the upper piston 20 is inserted into the rod insertion hole 18 and connected to the lower piston 10 and disposed on the upper side relative to the lower piston 10. [ The lower piston 10 and the upper piston 20 are inserted into the cylinder C without being separated from the inner wall of the cylinder C. On the other hand, the lower piston 10 and the upper piston 20 are connected to the piston ring 10 in accordance with the design of a person skilled in the art so that the airtightness between the lower piston 10 and the inner piston of the cylinder C is maintained. (Not shown) may be provided. Further, the upper piston 20 is selectively movable up and down with respect to the lower piston 10 as a reference. Here, the volume of the combustion chamber 1 changes according to the up-and-down movement of the upper piston 20, thereby changing the compression ratio of the mixer.

The combustion chamber 1 is a space formed between the piston P and the cylinder C. The intake valve 3 and the exhaust valve 5 are opened or closed to suck the mixer or exhaust the combustion gas. Here, the combustion gas discharged from the combustion chamber 1 is referred to as an exhaust gas. The opening and closing of the combustion chamber 1 and the intake / exhaust valves 3 and 5 are obvious to those skilled in the art, so a detailed description thereof will be omitted. In the embodiment of the present invention, the combustion chamber 1 is formed between the upper piston 20 and the cylinder C.

The upper piston (20) includes a connecting rod (22) and a push plate (24).

The connecting rod 22 is a part of the upper piston 20 inserted into the rod insertion hole 18. [ That is, the connection rod 22 is formed at a lower portion of the upper piston 20, and one end of the connection rod 22 is inserted into the operation chamber 14 through the rod insertion hole 18.

The push plate 24 is formed at one end of the connection rod 22 inserted into the rod insertion hole 18. [ Further, the push plate 24 is formed in a wide plate shape. Further, the push plate 24 is provided substantially on the inner wall of the operation chamber 14, and the operation chamber 14 is vertically partitioned by the push plate 24. Here, the hydraulic chamber 16 is a lower space of the upper space and the lower space of the operation chamber 14 partitioned by the push plate 24. [

The elastic member (26) is disposed in the upper space of the operation chamber (14). The elastic member 26 is provided to push the push plate 24 downward. Meanwhile, the elastic member 26 may be a coil spring, but is not limited thereto.

The hydraulic pressure supply circuit (40) is formed and arranged to supply hydraulic pressure to the hydraulic chamber (16). 1, the hydraulic pressure supply circuit 40 is formed in the connecting rod 30 and the lower piston 10, respectively. The hydraulic pressure supply circuit 40 formed on the connecting rod 30 communicates with the hydraulic pressure supply circuit 40 formed on the lower piston 10 and the hydraulic pressure supply circuit 40 formed on the lower piston 10 And communicates with the hydraulic chamber (16).

The hydraulic pressure supply unit 70 is a device that supplies the hydraulic pressure to the hydraulic pressure supply circuit 40. The hydraulic pressure supplied from the hydraulic pressure supply unit 70 is sequentially supplied to the hydraulic chamber 40 via the hydraulic pressure supply circuit 40 formed on the connecting rod 30 and the hydraulic pressure supply circuit 40 formed on the lower piston 10, (16). Meanwhile, the hydraulic pressure supply unit 70 may be a conventional oil pump 71 (see FIG. 4), but is not limited thereto. Further, the fluid (F) forming the hydraulic pressure supplied to the hydraulic chamber (16) through the hydraulic supply circuit (40) may be oil or gas.

2 is an operational view of a variable compression ratio apparatus according to an embodiment of the present invention.

The upper piston 20 ascends or descends with respect to the lower piston 10 in accordance with the amount of the fluid F filled in the hydraulic chamber 16, as shown in FIG. Here, the amount of the fluid F means an intensity of the hydraulic pressure.

2 (a) is a state in which the supply of hydraulic pressure to the hydraulic chamber 16 is cut off or the amount of the supplied fluid F is small, so that the upper piston 20 is in a lowered state, and FIG. 2 (b) The oil pressure is supplied to the upper piston 16 at a set value or higher, and the upper piston 20 is raised.

2 (a), when the hydraulic pressure supplied to the hydraulic chamber 16 from the hydraulic pressure supply unit 70 is cut off or the amount of the supplied fluid F is small, the elastic member 26 The upper piston 20 is lowered by a pushing force of the push plate 24. [ The lower surface of the upper piston 20, on which the connecting rod 22 protrudes, is in contact with the upper surface of the lower piston 10. Therefore, the volume of the combustion chamber 1 is increased.

2 (b), when the hydraulic pressure supplied to the hydraulic chamber 16 from the hydraulic pressure supply unit 70 is equal to or higher than a predetermined value, the fluid F is moved by the pushing force of the push plate 24, The upper piston 20 is raised. That is, the lower surface of the upper piston 20, on which the connecting rod 22 protrudes, is spaced from the upper surface of the lower piston 10. Therefore, the volume of the combustion chamber 1 is reduced. Here, the set value of the hydraulic pressure can be set by a person skilled in the art in consideration of the elastic force of the elastic member 26.

3 is a schematic view of a hydraulic supply circuit and a lubricant circuit according to an embodiment of the present invention.

3, the hydraulic supply circuit 40 includes first, second, third and fourth hydraulic lines 41, 43, 45, 47, and the lubrication circuits 42, 44, Oil supply portion 90 and first, second and third lubrication lines 42, 44, 46.

The first hydraulic line 41 is formed in the cylinder block 60. One end of the first hydraulic line 41 is connected to the hydraulic pressure supply unit 70.

The second hydraulic line 43 is formed in the crankshaft 50. One end of the second hydraulic line 43 communicates with the other end of the first hydraulic line 41.

The third hydraulic line 45 is a hydraulic pressure supply circuit 40 formed in the connecting rod 30 (see FIG. 1). One end of the third hydraulic line 43 communicates with the other end of the second hydraulic line 43. One end of the third hydraulic line 43 is formed at the large end portion 34 of the connecting rod 30 and the other end of the third hydraulic line 45 is connected to the small end portion 32 of the connecting rod 30, (32).

The fourth hydraulic line 47 is a hydraulic pressure supply circuit 40 formed in the lower piston 50 (see FIG. 1). One end of the fourth hydraulic line 47 communicates with the other end of the third hydraulic line 45 extending to the small end of the connecting rod 30 (see FIG. 1). As described above, the other end of the fourth hydraulic line 47 communicates with the hydraulic chamber 16.

The fluid F supplied from the hydraulic pressure supply unit 70 is supplied to the first hydraulic line 41, the second hydraulic line 43, the third hydraulic line 45 and the fourth hydraulic line 47, To the hydraulic chamber (16).

The lubrication circuit 42 includes a bearing 38 interposed in the connecting portion between the connecting rod 30 and the crankshaft 50 and a bearing 38 interposed between the connecting portion of the cylinder block 60 and the crankshaft 50 And is configured to supply oil for lubricating the interposed bearing 58. That is, the oil supplied through the first, second and third lubricating lines 42, 44 and 46 smoothly rotates the crankshaft 50.

The oil supply unit 90 supplies engine oil to the lubricating circuits 42, 44 and 46 from an engine oil reservoir (not shown) or an oil pan (not shown). The oil supply unit 90 includes an oil pump 71 and an oil control valve 72 (see FIG. 4). Here, the oil pump 71 is a device for pumping engine oil to be supplied to a portion to be supplied. The oil control valve 72 is connected to the oil pump 71, It is a device to control the amount of oil.

The first lubricating line (42) is formed in the cylinder block (60). One end of the first lubricating line 42 is connected to the oil supply unit 90.

The second lubrication line (44) is formed in the crankshaft (50). The second lubricating line 44 is formed at a portion where the crankshaft 50 is connected to the cylinder block 60. Further, the second lubricating line 44 is connected to the other end of the first lubricating line 42 extending to the connecting portion of the crankshaft 50 and the cylinder block 60. Meanwhile, the second lubricating line 44 may be formed to penetrate the crankshaft 50 in the radial direction of the bearing 58. Therefore, the oil that has passed through the first lubricating line 42 and the second lubricating line 44 lubricates the bearing 58 interposed in the connecting portion of the cylinder block 60 and the crankshaft 50.

The third lubricating line (46) is formed in the crankshaft (50) and branches off from the second lubricating line (44). That is, one end of the third lubricating line 46 is connected to the second lubricating line 44. The other end of the third lubricating line 46 extends to the connecting portion between the crankshaft 50 and the connecting rod 30. [ Therefore, the oil that has passed through the third lubricating line 46 lubricates the bearing 38 interposed in the connecting portion of the connecting rod 30 and the crankshaft 50.

The oil supplied to the first lubricating line 42 sequentially passes through the first lubricating line 42, the second lubricating line 44, and the third lubricating line 46, The oil that lubricates the bearings 38 and 58 can be dropped and recovered to the oil pan.

A connecting portion of the hydraulic pressure supply circuit 40 of the lower piston 10 and the connecting rod 30, a connecting portion of the connecting rod 30 and the hydraulic pressure supply circuit 40 of the crankshaft 50, A sealing member 80 is provided at the connection portion of the cylinder block 60 and the hydraulic pressure supply circuit 40 to prevent the loss of the fluid F. [ That is, the sealing member 80 is disposed between the first hydraulic line 41 and the second hydraulic line 43, between the second hydraulic line 43 and the third hydraulic line 45, Is interposed between the third hydraulic line (45) and the fourth hydraulic line (47). In order to prevent the loss of the fluid F due to the rotation of the crankshaft 50, the connection between the first hydraulic line 41 and the second hydraulic line 43 and the connection between the second hydraulic line 43, And the third hydraulic line (45) are each formed in a circular groove shape. The sealing member 80 (80) disposed at the connecting portion of the first hydraulic line 41 and the second hydraulic line 43 and at the connecting portion of the second hydraulic line 43 and the third hydraulic line 45, Is formed in a circular shape corresponding to the shape of the connecting portion of the first hydraulic line 41 and the second hydraulic line 43 and the connecting portion of the second hydraulic line 43 and the third hydraulic line 45 .

The sealing member 80 is disposed on the lower piston 10 so that the sealing member 80 provided on the lower piston 10 and the sealing member 80 provided on the lower piston 10 are hermetically contacted. Protrudes from the surface on which the connection portion of the hydraulic pressure supply circuit 40 of the rod 30 is formed. At this time, at least one of the sealing member 80 provided to the lower piston 10 and the sealing member 80 provided to the lower piston 10 protrudes. The sealing member 80 may be integrally formed with the connecting rod 30 so that the sealing member 80 provided on the connecting rod 30 and the sealing member 80 provided on the crankshaft 50 are hermetically contacted with each other. And protrudes from the surface of the crankshaft (50) where the connecting portion of the hydraulic pressure supply circuit (40) is formed. At this time, at least one of the sealing member 80 provided on the connecting rod 30 and the sealing member 80 provided on the crankshaft 50 is protruded. The sealing member 80 may be formed in the crankshaft 50 so that the sealing member 80 provided in the crankshaft 50 and the sealing member 80 provided in the cylinder block 60 are hermetically contacted with each other. And protrudes from the surface of the cylinder block 60 where the connection portion of the hydraulic pressure supply circuit 40 is formed. At this time, at least one of the sealing member (80) provided to the crankshaft (50) and the sealing member (80) provided to the cylinder block (60) protrudes.

4 is a block diagram of a hydraulic supply according to one embodiment of the present invention.

4, the hydraulic pressure supply unit 70 according to any one of the embodiments of the present invention includes an oil pump 71 and an oil control valve 72. As shown in Fig. Further, the hydraulic pressure supply unit 70 according to any one of the embodiments of the present invention is provided to supply the engine oil to the hydraulic pressure supply circuit 40. [

As described above, the oil pump 71 is a device for pumping engine oil to be supplied to a portion to be supplied, and the oil control valve 72 is provided between the oil pump 71 and a portion to which the engine oil is to be supplied It is a device that adjusts the amount of engine oil supplied.

The oil control valve 72 is connected to the first hydraulic line 41 and supplies the engine oil received from the oil pump 71 to the first hydraulic line 41. In addition, the oil control valve 72 regulates the amount of engine oil supplied to the first lubricating line 42. That is, the hydraulic pressure supply unit 70 according to any one of the embodiments of the present invention also serves as the oil supply unit 90. In other words, when the fluid F is engine oil, the oil supply portion 90 functions as the hydraulic pressure supply portion 70, and a separate hydraulic pressure supply portion 70 may not be required.

5 is a block diagram of a hydraulic supply according to another embodiment of the present invention.

5, the hydraulic pressure supply unit 70 according to another embodiment of the present invention includes a compressor unit 73 and a high-pressure pump 74. As shown in Fig. In addition, the hydraulic pressure supply unit 70 according to another embodiment of the present invention is provided to supply the exhaust gas to the hydraulic pressure supply circuit 40.

The compressor portion 73 is a portion where the exhaust gas compressed by the compressor side of the turbocharger T is located. Herein, the turbocharger T is a device for improving the engine output by pushing the air into the cylinder of the engine when the exhaust turbine is turned by the energy of the exhaust gas, and the compressor of the turbocharger T is a device The detailed description of the compressor unit 73 will be omitted.

The high pressure pump 74 is connected to the compressor unit 73 and receives the exhaust gas from the compressor unit 73. The high pressure pump 74 is connected to the first hydraulic line 41 and pumps the exhaust gas from the compressor unit 73 to supply the high pressure exhaust gas to the first hydraulic line 41 do. Furthermore, the exhaust gas supplied to the first hydraulic line 41 is supplied to the hydraulic chamber 16 through the hydraulic pressure supply circuit 40. [

6 is a block diagram of a hydraulic supply according to another embodiment of the present invention.

6, the hydraulic pressure supply unit 70 according to another embodiment of the present invention includes a turbine unit 75, an exhaust gas recirculation cooler 76, and a high-pressure pump 77 do. In addition, the hydraulic pressure supply unit 70 according to another embodiment of the present invention is provided to supply the exhaust gas to the hydraulic pressure supply circuit 40.

The turbine portion 75 is a portion where the exhaust gas is located on the exhaust turbine side of the turbocharger T. The turbine section 75 is located on the front end side of the exhaust turbine. That is, the turbine portion 75 is a portion where the exhaust gas not passing through the exhaust turbine is located.

The exhaust gas recirculation cooler 76 is connected to the turbine section 75 and receives exhaust gas from the turbine section 75. The exhaust gas recirculation cooler 76 is a device for cooling the exhaust gas transferred from the turbine unit 75. Further, the exhaust gas recirculation cooler 76 is provided to prevent the devices from being deteriorated by the recirculated hot exhaust gas.

The high-pressure pump 77 is connected to the exhaust gas recirculation cooler 76 and receives exhaust gas from the exhaust gas recirculation cooler 76. The high pressure pump 77 is connected to the first hydraulic line 41 and pumps the exhaust gas transferred from the exhaust gas recirculation cooler 76 to discharge the high pressure exhaust gas to the first hydraulic line 41. [ . Furthermore, the exhaust gas supplied to the first hydraulic line 41 is supplied to the hydraulic chamber 16 through the hydraulic pressure supply circuit 40. [

5 and 6, when the fluid F is an exhaust gas, the hydraulic pressure supply unit 70 and the oil supply unit 90, which are independently configured, are required. In addition, the operating time and operating time of the high-pressure pumps 74 and 77 can be controlled by an electronic control unit (ECU), which is typically mounted in an automobile.

7 is a view showing an exhaust gas recirculation passage according to an embodiment of the present invention.

The exhaust gas recirculation passage 78 according to the embodiment of the present invention is a passage formed to supply exhaust gas to the combustion chamber 1 when the fluid F is exhaust gas.

The exhaust gas recirculation passage (78) is formed in the upper piston (20). One end of the exhaust gas recirculation passage 78 communicates with the hydraulic chamber 16 and the other end communicates with the combustion chamber 1. That is, the exhaust gas recirculation passage 78 is formed to communicate the hydraulic chamber 16 and the combustion chamber 1. Further, a check valve 79 is disposed on the exhaust gas recirculation passage 78. The check valve 79 may be provided at the other end of the exhaust gas recirculation passage 78 communicated with the combustion chamber 1.

The check valve 79 selectively opens and closes the exhaust gas recirculation passage 78. That is, the hydraulic chamber 16 and the combustion chamber 1 are selectively communicated with each other by opening and closing the check valve 79. The check valve 79 is opened while the piston P descends during an intake stroke of the engine. Further, the opening of the check valve 79 is naturally performed by the pressure difference between the combustion chamber 1 and the hydraulic chamber 16. [ That is, the check valve 79, which is a one-way valve, is opened when the pressure of the hydraulic chamber 16 is higher than the pressure of the combustion chamber 1, and the check valve 79 is opened, The pressure difference of the hydraulic chamber 16 can be set by a person skilled in the art. For example, it may be set based on the pressure difference between the combustion chamber 1 and the hydraulic chamber 16 during the compression stroke of the engine, and the pressure difference may be 15 bar.

The other end of the exhaust gas recirculation passage 78 and the check valve 79 are connected to the upper surface edge of the upper piston 20 Can be disposed in close proximity.

As described above, according to the embodiment of the present invention, by using the hydraulic pressure for the operation of changing the top dead center of the piston P, the structure is simplified, the responsiveness of changing the compression ratio is improved, and the overall weight can be minimized. Therefore, the fuel consumption of the engine can be improved. Further, by using the exhaust gas to form the hydraulic pressure for performing the compression ratio change and supplying the exhaust gas used for the compression ratio change to the combustion chamber 1, the compression ratio change and the exhaust gas recirculation can be realized at the same time. The configuration for recirculation of the exhaust gas can be simplified.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And all changes to the scope that are deemed to be valid.

1: Combustion chamber 3: Intake valve
5: exhaust valve 10: lower piston
12: Pin hole 14: Working chamber
16: Hydraulic chamber 18: Rod insertion hole
20: upper piston 22: connecting rod
24: push plate 26: elastic member
30: connecting rod 32: small end
34: large end portion 35: piston pin
38, 58: Bearings
40: Hydraulic pressure supply circuit 41: First hydraulic line
42: first lubrication line 43: second hydraulic line
44: second lubrication line 45: third hydraulic line
46: third lubrication line 47: fourth hydraulic line
50: Crankshaft
60: Cylinder block
70: Hydraulic pressure supply unit 71: Oil pump
72: Oil control valve 73: Compressor part
74, 77: High pressure pump 75: Turbine part
76: Exhaust gas recirculation cooler 78: Exhaust gas recirculation passage
79: Check valve
80: Sealing member
P: Piston C: Cylinder
F: Fluid T: Turbocharger

Claims (12)

1. A variable compression ratio apparatus for changing a top dead center of a piston provided in an engine according to an operating state of an engine,
A lower piston provided reciprocably in a cylinder of the engine and connected to the connecting rod to rotate the crankshaft by reciprocating motion;
An operating chamber which is a space formed in the lower piston relatively above the portion connected to the connecting rod;
An upper piston disposed relatively above the lower piston and partially inserted into the working chamber;
A push plate formed on a portion of the upper piston to partition the operating chamber vertically;
A hydraulic chamber which is a lower space of the partitioned working chamber;
An elastic member provided in an upper space of the partitioned working chamber to push the push plate downward;
A hydraulic pressure supply unit for supplying hydraulic pressure to the hydraulic chamber such that the push plate is selectively pushed upward by hydraulic pressure; And
A hydraulic pressure supply circuit that connects the hydraulic pressure supply unit and the hydraulic chamber so that the hydraulic pressure is supplied to the hydraulic pressure chamber from the hydraulic pressure supply unit;
, ≪ / RTI &
And the fluid supplied to the hydraulic chamber to form the hydraulic pressure is a gas. The method according to claim 1,
Wherein the gas supplied to the hydraulic chamber and forming the hydraulic pressure is exhaust gas. 3. The method of claim 2,
The hydraulic-
A compressor section in which a compressed exhaust gas is located at a compressor side of the turbocharger; And
A high pressure pump which receives the exhaust gas from the compressor and pumps the exhaust gas to transfer the high pressure exhaust gas to the hydraulic pressure supply circuit;
Lt; / RTI >
And the high-pressure exhaust gas delivered to the hydraulic pressure supply circuit is supplied to the hydraulic chamber. The method of claim 3,
An exhaust gas recirculation passage formed in the upper piston to communicate the hydraulic chamber and the combustion chamber; And
A check valve disposed on the exhaust gas recirculation passage for selectively opening and closing the exhaust gas recirculation passage;
Further comprising:
And the exhaust gas is recirculated from the hydraulic chamber to the combustion chamber when the check valve is opened. 5. The method of claim 4,
Wherein the check valve is opened naturally when the hydraulic pressure difference between the hydraulic chamber and the combustion chamber is equal to or greater than a set value, and is naturally closed when the hydraulic pressure difference between the hydraulic chamber and the combustion chamber is less than a set value. 3. The method of claim 2,
The hydraulic-
A turbine section in which the exhaust gas is positioned at the front end side of the exhaust turbine of the turbocharger;
An exhaust gas recirculation cooler for receiving the exhaust gas from the turbine portion and cooling the exhaust gas; And
A high pressure pump that receives exhaust gas from the exhaust gas recirculation cooler and pumps the exhaust gas to transfer high pressure exhaust gas to an oil pressure supply circuit;
Lt; / RTI >
And the high-pressure exhaust gas delivered to the hydraulic pressure supply circuit is supplied to the hydraulic chamber. The method according to claim 6,
An exhaust gas recirculation passage formed in the upper piston to communicate the hydraulic chamber and the combustion chamber; And
A check valve disposed on the exhaust gas recirculation passage for selectively opening and closing the exhaust gas recirculation passage;
Further comprising:
And the exhaust gas is recirculated from the hydraulic chamber to the combustion chamber when the check valve is opened. 8. The method of claim 7,
Wherein the check valve is opened naturally when the hydraulic pressure difference between the hydraulic chamber and the combustion chamber is equal to or greater than a set value, and is naturally closed when the hydraulic pressure difference between the hydraulic chamber and the combustion chamber is less than a set value. The method according to claim 1,
Wherein when the hydraulic pressure in the hydraulic chamber is equal to or higher than a set value, the upper piston rises with respect to the lower piston,
Wherein when the hydraulic pressure is not supplied to the hydraulic chamber beyond a predetermined value, the push plate is retracted to abut on the lower piston in accordance with the urging of the elastic member. The method according to claim 1,
The hydraulic pressure supply circuit includes:
A first hydraulic line formed in the cylinder block and having one end connected to the hydraulic pressure supply;
A second hydraulic line formed on the crankshaft and having one end communicated with the other end of the first hydraulic line;
A third hydraulic line formed in the connecting rod and having one end communicated with the other end of the second hydraulic line; And
A fourth hydraulic line formed in the lower piston and having one end communicated with the other end of the third hydraulic line and the other end communicating with the hydraulic chamber;
And a variable compression ratio device. 11. The method of claim 10,
Wherein the fluid supplied from the hydraulic pressure supply unit is supplied to the hydraulic chamber sequentially through the first hydraulic line, the second hydraulic line, the third hydraulic line and the fourth hydraulic line sequentially. . 11. The method of claim 10,
A sealing member is provided at a portion where the hydraulic pressure supply circuits are connected,
At least one of the sealing members provided on each of the two confronting components such that the sealing member provided in each of the two components facing the fluid supply circuit is hermetically contacted protrudes from the surface on which the two components face And the variable compression ratio device.

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