A control device, a control method, and an engine that achieve continuous variable valve lift

Abstract

The application discloses a control device and method for realizing continuous variable valve lift and an engine, relates to the technical field of engine valve mechanism, and comprises a shell, a split piston cavity is further arranged on the shell, and a split piston capable of reciprocating motion is arranged in the split piston cavity; an oil leakage hole is formed in the side wall of a tappet, an oil leakage groove is arranged on the side wall of a tappet cavity, one end of the oil leakage hole penetrates the top end of the tappet and is communicated with a first oil path, the oil leakage hole is communicated with the oil leakage groove when the tappet moves to a set position, and the oil leakage groove is communicated with the split piston cavity through a second oil path; the continuous variable valve lift is realized by controlling the return position of the split piston in the split piston cavity, and then the valve lift is changed. The application solves the problem that the existing variable valve control device cannot realize the continuous adjustment of the valve lift.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, specifically relating to a control device, control method, and engine for realizing continuously variable valve lift. Background Technology

[0002] Traditional hydraulic continuously variable valve timing technology achieves variable valve lift by changing the valve opening and closing phase angles. However, this control method relies on the coordination of a camshaft synchronization mechanism to ensure good repeatability. Existing technologies use transmission gears or control cams to introduce camshaft synchronization, but both methods are structurally complex.

[0003] Existing technologies also disclose hydraulic two-stage variable valve technology, which, although requiring little or no synchronization signal, only offers two valve opening options. In addition, existing technologies have designed a two-stage variable valve that uses a solenoid valve to control a transfer piston to split and control the valve opening. The stroke of the transfer piston in this scheme is fixed, making it impossible to achieve continuous adjustment of valve lift and thus failing to meet the precise valve opening requirements of all engine operating conditions. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a control device, control method, and engine for achieving continuously variable valve lift, thus solving the problem that existing variable valve control devices cannot achieve continuous adjustment of valve lift.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a control device for achieving continuously variable valve lift, comprising a housing, a valve piston chamber and a tappet chamber disposed on the housing, a valve piston disposed in the valve piston chamber and a tappet disposed in the tappet chamber; the housing forms a first oil passage between the tappet and the valve piston, the valve piston moves along the piston chamber and the tappet moves along the tappet chamber; a transfer piston chamber is also disposed on the housing, a transfer piston capable of reciprocating motion is disposed in the transfer piston chamber; an oil drain hole is formed on the side wall of the tappet, and an oil drain groove is formed on the side wall of the tappet chamber, one end of the oil drain hole penetrates the top end of the tappet and communicates with the first oil passage, and when the tappet moves to a set position, the oil drain hole communicates with the oil drain groove, the oil drain groove is communicated with the transfer piston chamber through a second oil passage; the continuously variable valve lift is achieved by controlling the return position of the transfer piston in the transfer piston chamber.

[0006] As a further technical solution, the return position of the transfer piston is controlled by a push rod and a control cam. The control cam controls the length of the push rod extending into the transfer piston chamber. That is, the longer the push rod extends into the transfer piston chamber, the smaller the range of motion of the transfer piston and the larger the valve opening; conversely, the shorter the extension length, the larger the range of motion of the transfer piston and the smaller the valve opening.

[0007] As a further technical solution, the rotation of the control cam is controlled by a control motor and a worm gear mechanism. The control motor controls the rotation of the worm, the worm meshes with the worm wheel, the worm wheel is mounted on the control shaft, and the control cam is mounted on the control shaft.

[0008] As a further implementation, each control shaft is provided with at least one control cam, and the number of control cams is equal to the number of valves to be controlled.

[0009] As a further implementation, the valve piston is reciprocally mounted in the piston chamber of the housing, with one end connected to the valve and the other end in contact with hydraulic oil, thereby enabling the valve piston to move.

[0010] As a further implementation, the oil drain groove is annular, the core of the tappet is a blind hole structure, and an oil drain hole is provided through the side wall. When the position of the oil drain hole corresponds to that of the oil drain groove, the oil in the first oil passage enters the transfer piston chamber where the transfer piston is located through the oil drain hole, the oil drain groove, and the second oil passage.

[0011] As a further implementation, the closed end of the tappet is driven by a cam.

[0012] As a further implementation, an oil pump is also included, which supplies oil to the tappet chamber and the transfer piston chamber through a third oil circuit. The third oil circuit is equipped with a first check valve and a second check valve. The transfer piston chamber is connected to the second check valve and the first check valve by an oil circuit.

[0013] Secondly, the present invention also provides a control method for a control device that realizes continuously variable valve lift, comprising: Based on the different power demand signals from the engine control unit, the return position of the transfer piston in the transfer piston chamber is determined, thereby adjusting the range of motion of the transfer piston, and consequently adjusting the volume of hydraulic oil entering the valve piston chamber, so as to continuously adjust the valve stroke within a set range.

[0014] Thirdly, the present invention also provides an engine including the aforementioned control device for achieving continuously variable valve lift.

[0015] Compared with the prior art, the advantages and positive effects of this invention are: In this invention, the piston chamber, tappet chamber, and transfer piston chamber are interconnected and all are filled with hydraulic oil. By controlling the return position of the transfer piston in the transfer piston chamber, i.e., controlling the reciprocating range of the transfer piston, the volume of hydraulic oil in the transfer piston chamber is changed, thereby changing the volume of hydraulic oil in the valve piston chamber. Under the control of the tappet's fixed stroke, the total stroke of the valve changes, resulting in a change in valve lift. Under a stable operating condition, the volume of hydraulic oil in the transfer piston chamber remains constant, so the valve obtains a consistent lift that matches the operating condition in each working cycle, such as a small lift at idle and a large lift under heavy load, achieving low energy consumption, low wear, and high stability variable valve control. Under various continuously changing operating conditions, the volume of hydraulic oil in the transfer piston chamber is continuously changed to adapt to different engine operating conditions. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0017] Figure 1 This is an overall structural diagram of the control device of the present invention; Figure 2 This is a partially enlarged schematic diagram of the control device of the present invention; Figure 3 This is a schematic diagram of the control device of the present invention; Figure 4 This is a diagram showing the oil leakage curves under different valve openings according to the present invention.

[0018] In the diagram: 1. Valve; 2. Valve piston; 3. Housing; 4. Tappet; 5. Drain groove; 6. Drain hole; 7. Cam; 8. Drive motor; 9. Control shaft; 10. Push rod; 11. Transfer piston; 12. Control cam; 13. Worm gear; 14. Worm; 15. Tappet chamber; 16. Transfer piston chamber; 17. Valve piston chamber; 18. Oil pump; 19. First check valve; 20. Second check valve; 21. First oil passage; 22. Second oil passage; 23. Third oil passage; 24. Oil tank; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. Example 1 This embodiment discloses a control device for achieving continuously variable valve lift, such as... Figures 1-2 As shown.

[0020] With increasingly stringent vehicle emission and fuel consumption regulations, variable valve timing technology is gaining wider application due to its significant energy-saving and environmentally friendly effects. Traditional hydraulic continuously variable valve timing technology achieves variable valve lift by changing the valve opening and closing phase angles, but this control method relies on the cooperation of a camshaft synchronization mechanism to ensure good repeatability. Existing technologies use transmission gears to introduce camshaft synchronization, or control cams to introduce synchronization, but both methods are structurally complex.

[0021] Existing technologies also disclose hydraulic two-stage variable valve technology, which, although requiring little or no synchronization signal, only offers two valve opening options. In addition, existing technologies have designed a two-stage variable valve that uses a solenoid valve to control a transfer piston to split and control the valve opening. The stroke of the transfer piston in this scheme is fixed, making it impossible to achieve continuous adjustment of valve lift and thus failing to meet the precise valve opening requirements of all engine operating conditions.

[0022] This embodiment proposes a control device for achieving continuously variable valve lift, such as... Figure 1 - Figure 2 As shown, the device includes a housing 3, within which a valve piston chamber 17 is provided for mounting a valve piston 2. The housing 3 also includes a tappet chamber 15 for mounting a tappet 4. The tappet 4 has a fixed stroke within the tappet chamber 15. A transfer piston chamber 16 is located on one side of the tappet chamber 15. The tappet chamber 15, the transfer piston chamber 16, and the valve piston chamber 17 are connected, and each chamber is filled with hydraulic oil. A transfer piston 11 is located in the transfer piston chamber 16, allowing for changes in the range of motion of the transfer piston 11. This changes the volume of hydraulic oil entering the transfer piston chamber 16, thereby changing the travel of the valve piston 2 and thus changing the lift of the valve 1. The tappet 4 has an oil drain hole 6 on its side wall and an oil drain groove 5 on its side wall. One end of the oil drain hole 6 passes through the top of the tappet and is connected to the first oil passage 21. When the tappet moves to the set position, the oil drain hole 6 can be connected to the oil drain groove 5. The oil drain groove 5 is connected to the transfer piston chamber 16 through the second oil passage 22. Furthermore, in this embodiment, the range of motion of the transfer piston 11 is controlled by the push rod 10 and the control cam 12. One end of the push rod 10 is connected to the transfer piston 11, and the other end is provided with a drive part perpendicular to the axis of the push rod 10. One side of the drive part abuts against the control cam 12 to drive the push rod 10, and the other side is provided with an elastic component between it and the housing 3 to realize the reset of the push rod 10. In this embodiment, the reciprocating range of the transfer piston 11 is limited by the push rod 10. The push rod 10 and the housing 3 are in a sliding fit. The longer the length of the push rod 10 extending into the transfer piston cavity 16, the smaller the range of motion of the transfer piston 11 and the larger the valve opening; conversely, the shorter the extension length, the larger the range of motion of the transfer piston 11 and the smaller the valve opening.

[0023] It is understandable that the valve piston chamber 17 and the tappet chamber 15 are connected by a first oil passage 21, and a second oil passage 22 is provided between the transfer piston chamber 16 and the tappet chamber 15. The two can be connected when the tappet moves to a certain position. Both the valve piston chamber 17 and the tappet chamber 15 are filled with hydraulic oil. Since the stroke of the tappet 4 in the tappet chamber 15 is fixed, it always follows the base circle or lift profile of the cam 7 shaft. The control cam 12 limits the range of motion of the transfer piston 11 through the push rod 10, changing the volume of hydraulic oil entering the transfer piston chamber 16. Therefore, the change in the hydraulic oil used to drive the valve piston 2 in the valve piston chamber 17, under the control of the fixed stroke of the tappet 4, causes the total stroke of the valve 1 to change, which in turn causes the valve 1 lift to change, that is, the valve 1 opening amplitude to change.

[0024] When engine operating conditions change, the control cam 12 rotates to the corresponding angle and locks. The control cam 12 changes the range of motion of the transfer piston 11 through the push rod 10. After the range of motion of the transfer piston 11 is fixed, hydraulic oil is distributed in a fixed proportion, thereby limiting the actual travel of the valve piston 2. Under a stable operating condition, the control cam 12 stops rotating, and the range of motion of the transfer piston 11 remains constant. Therefore, the valve 1 obtains a consistent lift that matches the operating condition in each working cycle, such as a small lift at idle and a large lift under heavy load, achieving low energy consumption, low wear, and high stability variable valve 1 control. Under various continuously changing operating conditions, the control cam 12 continues to rotate, and the range of motion of the transfer piston 11 continues to change to adapt to different engine operating conditions.

[0025] like Figure 3As shown, the tappet chamber 15 and the transfer piston chamber 16 are connected by a second oil passage 22, and the tappet chamber 15 is connected to the valve piston chamber 17 by a first oil passage 21. Oil supply lines are provided on the second oil passage 22 and the first oil passage 21 to supply oil to the tappet chamber 15, the transfer piston chamber 16 and the valve piston chamber 17, so as to ensure that the total volume of hydraulic oil in the tappet chamber 15, the transfer piston chamber 16 and the valve piston chamber remains unchanged, thereby ensuring the accuracy of the valve lift change.

[0026] Furthermore, the oil pump 18 is connected to the oil tank 24. The oil pump 18 supplies oil to the tappet chamber 15 and the transfer piston chamber 16 through the third oil passage 23. The third oil passage 23 is equipped with a second check valve 20 and a first check valve 19, and the transfer piston chamber 16 is connected to the second check valve 20 and the first check valve 19 through the connecting oil passage. The second check valve 20 and the first check valve 19 ensure that the hydraulic oil can only enter the third oil passage 23, the first oil passage 21 and the second oil passage 22 from the oil tank 24, and cannot flow back. The hydraulic oil in the transfer piston chamber 16 is supplied to the first oil passage 21 through the third oil passage 23.

[0027] As a further implementation, a control mechanism is provided on the top of the housing 3. The control mechanism includes a drive motor 8 and a worm gear mechanism. The drive motor 8 drives the worm 14, which meshes with the worm wheel 13. The worm wheel 13 is mounted on the control shaft 9, and a control cam 12 is mounted on the end of the control shaft 9. The angle change of the control cam 12 is realized through the control mechanism.

[0028] Understandably, the drive motor 8 outputs torque through the worm gear 14 on its output shaft. After being reduced and amplified by the worm gear mechanism, the torque drives the control shaft 9 of the worm gear 13 to rotate. The control shaft 9 then drives the control cam 12 to rotate to the target angle and maintains its position using the self-locking characteristic of the worm gear. The drive motor 8 can rotate forward or backward according to the command of the engine control unit, causing the control cam 12 to rotate forward or backward.

[0029] The worm gear 13 and worm 14 mechanism has a reverse self-locking function, which means that after the drive motor 8 is de-energized, the control cam 12 is unable to drive the worm gear 13 in the reverse direction due to the reverse force of the push rod 10 and the transfer piston 11. Therefore, the control cam 12 can maintain a stable angle without the drive motor 8 being continuously energized in a single working condition, which saves electricity and avoids heat generation. At the same time, it prevents the valve 1 lift from drifting due to accidental rotation of the control cam 12.

[0030] The worm gear mechanism can convert the high speed and low torque of the motor into the low speed and high torque of the control shaft 9. A very small motor rotation angle can correspond to the small angle change of the control cam 12, so as to achieve the lifting stage.

[0031] As a further implementation, each control shaft 9 is provided with at least one control cam 12, and the number of control cams 12 is equal to the number of valves to be controlled, so as to control multiple cylinders simultaneously.

[0032] Specifically, in the control mechanism above the housing 3, at least one control cam 12 is provided on each control shaft 9, and the number of control cams 12 is equal to the number of valves to be controlled. The drive motor 8 drives the control shaft 9 to rotate through a worm gear mechanism, and all the control cams 12 on the control shaft 9 rotate synchronously. Each control cam 12 controls a push rod 10, that is, controls the range of motion of the corresponding transfer piston 11. Since all the control cams 12 are mounted on the same control shaft 9, they have the same angular position, so the range of motion of the transfer piston 11 of each cylinder is consistent, thereby making the stroke of the valve piston 2 of each cylinder the same, realizing the synchronous adjustment of the lift of the valve 1 of all cylinders.

[0033] As a further implementation, the valve piston 2 is reciprocally mounted in the valve piston chamber 17, with one end of the valve piston 2 connected to the valve 1 and the other end in contact with hydraulic oil, thereby realizing the movement of the valve piston 2.

[0034] Specifically, the valve piston 2 is reciprocally mounted in the valve piston chamber 17 of the housing 3, with one end directly or indirectly connected to the valve stem 1, and the other end in contact with the hydraulic oil in the valve piston chamber 17. The tappet 4 in the tappet chamber 15 reciprocates with a fixed stroke under the drive of the cam 7 shaft, compressing the hydraulic oil; the hydraulic oil simultaneously acts on the medium-side end face of the valve piston 2 via the oil passage. The control cam 12 controls the position of the push rod 10, thereby changing the range of motion of the transfer piston 11, thus adjusting the hydraulic oil distribution ratio: the more hydraulic oil in the transfer piston chamber 16, the more medium is distributed, the shorter the total stroke of the valve piston 2, and the smaller the valve lift; the less hydraulic oil in the transfer piston chamber 16, the more concentrated the medium acts on the valve piston 2, the greater the total stroke, and the greater the valve lift.

[0035] As a further implementation, an annular oil drain groove 5 is provided on the side wall of the tappet cavity 15, the core of the tappet 4 is a blind hole structure, and an oil drain hole 6 is provided through the side wall. When the positions of the oil drain hole 6 and the oil drain groove 5 are corresponding, the tappet cavity 15 and the transfer piston cavity 16 are connected.

[0036] An annular oil drain groove 5 is provided on the side wall of the tappet cavity 15. The core of the tappet 4 has a blind hole structure, and an oil drain hole 6 is provided through the side wall. During the fixed-stroke reciprocating motion of the tappet 4 in the tappet cavity 15, when the camshaft rotates to a certain phase angle, the oil drain hole 6 on the tappet 4 corresponds to the position of the annular oil drain groove 5 to start the oil draining process. For different valve openings, the phase angle of the camshaft rotation corresponding to the end of the oil draining is different, such as... Figure 4As shown. Hydraulic oil or leaking medium in the blind hole of tappet 4 can flow into the drain groove 5 through the drain hole 6 and enter the transfer piston chamber 16, thereby changing the volume of the valve piston chamber 17 by changing the volume of the transfer piston chamber 16.

[0037] As a further implementation, the closed end of the tappet 4 abuts against the cam 7 on the cam 7 shaft.

[0038] Specifically, when the cam 7 rotates, the cam 7 pushes the tappet 4 to reciprocate within the tappet cavity 15 with a fixed stroke via the cylindrical drive unit. As the tappet 4 moves, it compresses the hydraulic oil within the tappet cavity 15. This hydraulic medium acts on the valve piston 2 via the oil passage, driving the valve 1 to open. Simultaneously, the hydraulic oil flow rate can be adjusted according to the hydraulic oil distribution set by the control cam 12, thereby regulating the actual stroke of the valve piston 2. The tappet 4 contacts the cam 7, converting the rotational motion of the cam 7 into the linear reciprocating motion of the tappet 4, thus achieving the pressure build-up and release of the hydraulic oil, ultimately controlling the reciprocating movement of the valve 1.

[0039] Example 2 This embodiment discloses a method for operating a control device that enables continuously variable valve lift, comprising: a drive motor 8 determining the rotation angle of a control cam 12 based on different power demand signals from an engine control unit; the control cam 12 pushing a push rod 10 to move, thereby adjusting the range of motion of the transfer piston 11, and thus adjusting the volume of hydraulic oil entering the valve piston chamber 17, thereby adjusting the valve stroke.

[0040] Specifically, the engine control unit calculates the required oil pressure or power demand of the engine based on the current speed, load, accelerator pedal position, and coolant temperature.

[0041] The engine control unit converts the demand into the corresponding target volume value of the transfer piston chamber 16 and sends it to the controller of the drive motor 8 in the form of a signal. After receiving the signal, the controller of the drive motor 8 rotates the drive motor 8 and uses the position sensor built into the drive motor 8 to achieve closed-loop control.

[0042] The drive motor 8 drives the control cam 12 to rotate to a specified angle, which corresponds one-to-one with the target volume of the transfer piston chamber 16. This correspondence needs to be pre-calibrated in the early stages of the design.

[0043] The outer contour of the control cam 12 has a specific lift curve. When the control cam 12 rotates, its contour surface pushes the push rod 10 to produce linear movement.

[0044] When it is necessary to reduce the lift of valve 1, the length of pushrod 10 extending into the transfer piston chamber 16 becomes shorter, the range of motion of transfer piston 11 becomes larger, the volume of hydraulic oil entering the transfer piston chamber 16 becomes larger, which in turn reduces the pressure of the first oil passage 21, thereby reducing the stroke of valve piston 2 and changing the opening of valve 1.

[0045] When it is necessary to increase the lift of valve 1, the length of pushrod 10 extending into the transfer piston chamber 16 becomes longer, the range of motion of transfer piston 11 becomes smaller, the volume of hydraulic oil entering the transfer piston chamber 16 becomes smaller, and the valve opening becomes larger; by changing the size of valve 1, the intake and exhaust volume of the engine are adjusted, thereby adapting to different engine output power.

[0046] Example 3 This embodiment discloses an engine in which the engine control unit collects the current engine speed, load, accelerator pedal position, and coolant temperature in real time, calculates the required oil pressure or power demand, and calculates the target volume value of the transfer piston chamber 16 based on the demand, which is then sent to the drive motor 8 in the form of an electrical signal. The drive motor 8 rotates its shaft according to the signal, causing the control cam 12 to stop at a preset phase angle.

[0047] The outer contour of the control cam 12 pushes the push rod 10 to a designated position according to a preset lift curve. The reciprocating range of the transfer piston 11 is limited by the push rod 10. When the length of the push rod 10 pushed into the transfer piston chamber 16 changes, the push rod 10 and the housing 3 are in sliding fit. The longer the push rod 10 extends into the transfer piston chamber 16, the smaller the range of motion of the transfer piston 11 and the larger the valve opening. Conversely, the shorter the extension length, the larger the range of motion of the transfer piston 11 and the smaller the valve opening.

[0048] By continuously adjusting the lift of valve 1, the engine intake and exhaust volumes are changed in real time, thereby matching the corresponding output power under different operating conditions and realizing continuous variable control of the engine valve lift.

[0049] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A control device for achieving continuously variable valve lift, comprising a housing, a valve piston chamber and a tappet chamber disposed on the housing, a valve piston disposed in the valve piston chamber, and a tappet disposed in the tappet chamber; the housing forms a first oil passage between the tappet and the valve piston, the valve piston moving along the piston chamber, and the tappet moving along the tappet chamber; characterized in that, The housing is further provided with a transfer piston chamber, in which a transfer piston capable of reciprocating motion is disposed; an oil drain hole is provided on the side wall of the tappet, and an oil drain groove is provided on the side wall of the tappet chamber; one end of the oil drain hole passes through the top of the tappet and is connected to the first oil passage, and when the tappet moves to a set position, the oil drain hole is connected to the oil drain groove, and the oil drain groove is connected to the transfer piston chamber through a second oil passage; the valve lift is continuously variable by controlling the return position of the transfer piston in the transfer piston chamber.

2. The control device for achieving continuously variable valve lift as described in claim 1, characterized in that, The return position of the transfer piston is controlled by a push rod and a control cam, and the control cam controls the length of the push rod extending into the transfer piston chamber.

3. The control device for achieving continuously variable valve lift as described in claim 2, characterized in that, The rotation of the control cam is controlled by a control motor and a worm gear mechanism. The control motor controls the rotation of the worm, which meshes with the worm gear. The worm gear is mounted on a control shaft, and the control cam is mounted on the control shaft.

4. The control device for achieving continuously variable valve lift as described in claim 3, characterized in that, Each control shaft is provided with at least one control cam, and the number of control cams is equal to the number of valves to be controlled.

5. The control device for achieving continuously variable valve lift as described in claim 1, characterized in that, The valve piston is reciprocally mounted in the valve piston chamber of the housing. One end of the valve piston is connected to the valve, and the other end is in contact with the hydraulic oil, thereby realizing the movement of the valve piston.

6. The control device for achieving continuously variable valve lift as described in claim 1, characterized in that, The oil drain groove is annular, the core of the tappet is a blind hole structure, and an oil drain hole is provided through the side wall. When the position of the oil drain hole corresponds to that of the oil drain groove, the oil in the first oil passage enters the transfer piston chamber where the transfer piston is located through the oil drain hole, the oil drain groove, and the second oil passage.

7. The control device for achieving continuously variable valve lift as described in claim 1, characterized in that, The closed end of the tappet is driven by a cam.

8. The control device for achieving continuously variable valve lift as described in claim 1, characterized in that, It also includes an oil pump, which supplies oil to the tappet chamber and the transfer piston chamber through a third oil circuit. The third oil circuit is equipped with a first check valve and a second check valve. The transfer piston chamber is connected to the second check valve and the first check valve by an oil circuit.

9. The control method of the control device for realizing continuously variable valve lift as described in any one of claims 1-8, characterized in that, include: Based on the different power demand signals from the engine control unit, the return position of the transfer piston in the transfer piston chamber is determined, thereby adjusting the range of motion of the transfer piston, and consequently adjusting the volume of hydraulic oil entering the valve piston chamber, so as to continuously adjust the valve stroke within a set range.

10. An engine, characterized in that, Includes the control device for achieving continuously variable valve lift as described in any one of claims 1-8.

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