Electro-hydraulic variable valve timing actuator capable of achieving seating buffering and actuation methods therefor

Abstract

An electro-hydraulic variable gas distribution actuator for an internal combustion engine gas distribution mechanism capable of providing seating buffering. The electro-hydraulic variable valve mechanism reduces seating speed and impact force. The actuator comprises upper, middle, and lower driving cavities, and upper, middle, and lower buffering cavities, and has a cylinder body 1 provided with a driving inner ring groove 18 and a control oil port 19 at the driving middle cavity. The control oil ports are connected with a reversing valve 24 which is connected with low- and high-pressure oil rails 25 & 26. A valve sleeve 8 is provided with an oil port at the driving middle cavity, and a one-way valve 13 is arranged between the upper and middle driving cavities and between the upper and middle buffering chambers. A second one-way valve is located between the driving lower chamber and a buffer lower chamber, and a buffer groove is provided in the buffer piston 2. A spring 14 is provided below the buffering piston.

Description

[0001] The present disclosure belongs to the field of valve trains of internal combustion engines, and in particular to an electro-hydraulic variable valve actuator capable of achieving seating buffering, and an actuation method therefor. BACKGROUND

[0002] The traditional valve train is composed of a cam, a tappet, a push rod, a rocker arm and an air valve, and is a purely mechanical mechanism. Although this mechanism has the advantages of simple structure and high reliability, with the increasing demands for valve timing, such a transmission mechanism faces the problems of huge volume, impact noise, and the like. Moreover, the purely mechanical mechanism means that it is difficult to change valve timing parameters, which also limits the traditional internal combustion engine from changing its valve timing strategy for different working conditions. Variable valve timing technology can achieve variable valve timing and lift according to engine load and speed, and meet the valve distribution requirements in different working conditions. Electro-hydraulic cam-less variable valve timing has the characteristics of high power density and variable and flexible structure. However, there are still some problems in the buffering performance of the electro-hydraulic variable valve train, such as fast seating speed and large impact. SUMMARY

[0003] In view of this, the present disclosure aims to provide an electro-hydraulic variable valve actuator capable of achieving seating buffering, and an actuation method therefor, so as to solve the problems of fast seating speed and large impact in the buffering performance of an existing electro-hydraulic variable valve train.

[0004] In order to achieve the objective of the present disclosure, the following technical solution is adopted: An electro-hydraulic variable valve actuator capable of achieving seating buffering includes an upper driving chamber, a middle driving chamber, a lower driving chamber, an upper buffering chamber, a middle buffering chamber, and a lower buffering chamber. The upper driving chamber is composed of a cylinder body, an upper end face of a valve sleeve, and an air valve piston. The middle driving chamber is composed of an inner surface of the valve sleeve, and an 24 10 24 upper end of the air valve piston. The lower driving chamber is composed of a lower end of the air valve piston, the inner surface of the valve sleeve, and an upper end face of a cylinder head. The upper buffering chamber is composed of the cylinder body, and an upper end face of a buffering piston. The middle buffering chamber is composed of a buffering inner ring groove, and a side face of the buffering piston. The lower buffering chamber is composed of the cylinder body, and a lower end face of the buffering piston. The cylinder body is provided with a medium-pressure oil port at the lower buffering chamber, and the medium-pressure oil port can be shielded by the buffering piston. The cylinder body is provided with an oblique oil passage communicating with the medium-pressure oil port, and the medium-pressure oil port and the lower driving chamber both communicate with a medium-pressure oil rail. The cylinder body is provided with a driving inner ring groove and a control oil port at the middle driving chamber, the control oil port is connected to a reversing valve through a pipeline, and the reversing valve is connected to a low-pressure oil rail, and a high-pressure oil rail. The valve sleeve is provided with a radial oil flow port at the middle driving chamber, and the radial oil flow port communicates with the driving inner ring groove. The valve sleeve is provided with multiple lift control oil holes at the lower driving chamber, and the multiple lift control oil holes are arranged in an axial direction of the valve sleeve, and can be shielded by the air valve piston. A first one-way valve is arranged between the upper driving chamber and middle driving chamber and the upper buffering chamber and middle buffering chamber, and a second one-way valve is arranged between the upper driving chamber and the lower buffering chamber. The buffering piston is provided with a buffering groove, and a buffering spring is arranged between the buffering piston.

[0005] Furthermore, the valve sleeve is provided with a fan-shaped ring groove, and a one-way oil inlet. The fan-shaped ring groove and the one-way oil inlet communicate with the lower driving chamber.

[0006] Furthermore, an outer side of the cylinder body is provided with an extension block, the extension block is provided with a third one-way valve, and the third one-way valve communicates with the medium-pressure oil rail. Medium-pressure oil, after passing through the third one-way valve, enters the lower driving chamber through the fan-shaped ring groove and the one-way oil inlet.

[0007] Furthermore, the valve sleeve is connected to a worm gear, and the worm gear is meshed with a worm.

[0008] Furthermore, the cylinder body is provided with a separation block, a bottom of the separation block is provided with an adjusting knob, and the adjusting knob is in contact with one 24 10 24 end of the buffering spring.

[0009] Furthermore, the bottom of the separation block is provided with a sealing block, and the adjusting knob is arranged on the sealing block.

[0010] Furthermore, the buffering groove is of a stepped groove structure, and a flow area of the stepped groove gradually decreases from top to bottom.

[0011] Furthermore, each of the first one-way valve and the second one-way valve is a built-in structure, and a flow rate of the first one-way valve is greater than that of the second one-way valve.

[0012] An actuation method for an electro-hydraulic variable valve actuator includes the following steps:

[0013] when a valve is opening, connecting a reversing valve to a high-pressure oil rail, and enabling high-pressure oil to flow from a lift control oil hole and a driving inner ring groove to a middle driving chamber and to enter an upper driving chamber and an upper buffering chamber through a first one-way valve, where the high-pressure oil in the upper driving chamber and the high-pressure oil in the upper buffering chamber respectively push an air valve piston and a buffering piston to descend, when the buffering piston descends, hydraulic oil in a lower buffering chamber flows to a medium-pressure oil rail through a medium-pressure oil port, and when the air valve piston descends, hydraulic oil in a lower driving chamber enters an oblique oil passage through a radial oil flow port, enters the lower buffering chamber through a second one-way valve, and finally flows to the medium-pressure oil rail; when a lower edge of the buffering piston descends to completely cover the medium-pressure oil port, the buffering piston stops moving, and when a lower edge of the air valve piston descends to completely cover the lift control oil hole, the air valve piston stops moving;

[0014] when the valve begins to fall back, connecting the reversing valve to a low-pressure oil rail, enabling the high-pressure oil in the upper driving chamber and the high-pressure oil in the upper buffering chamber to flows to a control oil port corresponding to a middle driving chamber only through a buffering groove on the buffering piston due to the influence of the first one-way valve, wherein when the air valve begins to fall back, the upper buffering chamber is in a high-pressure state, and the buffering piston is at a lower position at the moment, and when the hydraulic oil flows to the control oil port through the buffering groove, oil pressure in the upper buffering chamber begins to drop, and the buffering piston is pushed upwards under the action of the buffering spring and the medium-pressure oil pressure, which makes a flow area of the buffering groove reduced to further limit an outflow speed of the high-pressure oil, thereby achieving the 24 10 24 purpose of reducing a seating speed and achieving buffering effect of seating.

[0015] Furthermore, a worm is driven by a motor to drive a worm gear to rotate, a rotary valve sleeve is connected through a key groove to achieve the switching between the lift control oil hole on the valve sleeve and an oil passage on a left side leading to the lower buffering chamber, thus changing a position of completely covering the oil hole when the air valve piston has the maximum lift, and achieving lift transformation.

[0016] Compared with the prior art, the present disclosure has the beneficial effects that:

[0017] 1. The valve timing can be adjusted using only one reversing valve, and compared with the use of a proportional valve, the occupied space is smaller.

[0018] 2. According to the present disclosure, the lift is controlled by a motor, the valve timing is sequentially controlled by the reversing valve, and thus the lift and the timing can be independently controlled.

[0019] 3. The rotary adjusting knob can effectively change the buffering effect, and can make up for the problems of poor buffering caused by machining errors, leakage and the like, and the consistency of multiple cylinders can be improved through the adjusting knob.

[0020] 4. When the valve is seated, the flow rate adjustment is achieved through pressure balance, thus achieving seating buffering. The problems of excessive buffering, viscosity change caused by temperature rise and the like can be avoided to a certain extent by the pressure balance mode, and the seating impact can be effectively reduced.

[0021] 5. Due to the use of a worm gear and worm mechanism, and mutually independent movement of the valve sleeve and the air valve piston, a torque required for driving the valve sleeve to rotate is small. There is a certain repeated included angle between the radial oil hole on the valve sleeve and the oil passage communicating with the cylinder body. Therefore, a motor can simultaneously control multiple cylinders with different time sequence states.

[0022] 6. Due to the built-in one-way valve and oblique oil passage, the length of an oil circuit is reduced, and the volume of an oil chamber is further reduced, thus facilitating the response improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure, and the illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure, and do not constitute an undue limitation of the present disclosure. In the drawings: 24 10 24

[0024] FIG. 1 is a schematic diagram of a sectional structure of an electro-hydraulic variable valve actuator capable of achieving seating buffering according to the present disclosure;

[0025] FIG. 2 is a schematic diagram of a three-dimensional structure of an electro-hydraulic variable valve actuator capable of achieving seating buffering according to the present disclosure;

[0026] FIG. 3 is a sectional diagram of a three-dimensional structure of an electro-hydraulic variable valve actuator capable of achieving seating buffering according to the present disclosure;

[0027] FIG. 4 is a schematic diagram of an enlarged structure of a connection of a valve sleeve and a cylinder body according to the present disclosure;

[0028] FIG. 5 is a schematic diagram of high-pressure oil in the descending working process of a driving valve at high lift according to the present disclosure;

[0029] FIG. 6 is a schematic diagram of medium-pressure oil in the descending working process of a driving valve at high lift according to the present disclosure;

[0030] FIG. 7 is a schematic diagram of low-pressure oil in the fallback working process of a valve at high lift according to the present disclosure;

[0031] FIG. 8 is a schematic diagram of medium-pressure oil in the fallback working process of a valve at high lift according to the present disclosure;

[0032] FIG. 9 is a structural diagram of an electro-hydraulic variable valve actuator capable of achieving seating buffering according to the present disclosure in AMESim;

[0033] FIG. 10 is a lift graph of a piston of an electro-hydraulic variable valve actuator capable of achieving seating buffering according to the present disclosure in AMESim;

[0034] FIG. 11 is a displacement graph of a buffering piston of an electro-hydraulic variable valve actuator capable of achieving seating buffering according to the present disclosure in AMESim;

[0035] FIG. 12 is a schematic diagram of a three-dimensional structure of a buffering groove of a buffering piston according to the present disclosure;

[0036] FIG. 13 is a schematic diagram of a three-dimensional sectional structure of a fan-shaped ring groove and a one-way oil inlet on a valve sleeve according to the present disclosure;

[0037] FIG. 14 is a schematic diagram of a sectional structure of a two-dimensional structure of a valve sleeve according to the present disclosure.

[0038] 1-cylinder body; 2-buffering piston; 3-separation block; 4-buffering spring; 5-adjusting knob; 6-sealing block; 7-air valve piston; 8-valve sleeve; 9-extension block; 10-worm gear; 11-worm; 12-cylinder head; 13-first one-way valve; 14-second one-way valve; 15-oblique oil passage; 16-medium-pressure oil port; 17-buffering inner ring groove; 18-driving inner ring groove; 19-control oil port; 20-fan-shaped ring groove; 21-one-way oil inlet; 22-radial oil flow port; 23-lift 24 10 24 control oil hole; 24-reversing valve; 25-low-pressure oil rail; 26-high-pressure oil rail; 27-medium-pressure oil rail; 28-high-pressure oil streamline; 29-first medium-pressure oil streamline; 3O-low-pressure oil streamline; 31-second medium-pressure oil streamline; 32-control oil supply; 33-medium-pressure oil supply; 34-driving chamber and air valve modeling; 35-buffering chamber modeling; 36-actuator model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The following clearly describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. It should be noted that the embodiments in the present disclosure and features in the embodiments can be mutually combined without conflict, and the described embodiments are merely a part but not all of the embodiments of the present disclosure.

[0040] The embodiment is described with reference to FIG. 1 to FIG. 14, an electro-hydraulic variable valve actuator capable of achieving seating buffering includes an upper driving chamber, a middle driving chamber, a lower driving chamber, an upper buffering chamber, a middle buffering chamber, and a lower buffering chamber. The upper driving chamber is composed of a cylinder body 1, an upper end face of a valve sleeve 8, and an air valve piston 7. The middle driving chamber is composed of an inner surface of the valve sleeve 8, and an upper end of the air valve piston 7. The lower driving chamber is composed of a lower end of the air valve piston 7, the inner surface of the valve sleeve 8, and an upper end face of a cylinder head 12. The upper buffering chamber is composed of the cylinder body 1, and an upper end face of a buffering piston 2. The middle buffering chamber is composed of a buffering inner ring groove 17, and a side face of the buffering piston 2. The lower buffering chamber is composed of the cylinder body 1, and a lower end face of the buffering piston 2. The cylinder body 1 is provided with a medium-pressure oil port 16 at the lower buffering chamber, and the medium-pressure oil port 16 can be shielded by the buffering piston 2. The cylinder body 1 is provided with an oblique oil passage 15 communicating with the medium-pressure oil port 16, and the medium-pressure oil port 16 and the lower driving chamber both communicate with a medium-pressure oil rail 27. The cylinder body 1 is provided with a driving inner ring groove 18 and a control oil port 19 at the middle driving chamber, the control oil port 19 is connected to a reversing valve 24 through a pipeline, and the reversing valve 24 is connected to a low-pressure oil rail 25, and a high-pressure oil rail 26. The valve sleeve 8 is provided with a radial oil flow port 22 at the middle driving chamber, and the radial oil flow port 22 communicates with the driving inner ring groove 18. The valve 24 10 24 sleeve 8 is provided with multiple lift control oil holes 23 at the lower driving chamber, and the multiple lift control oil holes 23 are arranged in an axial direction of the valve sleeve 8, and can be shielded by the air valve piston 7. A first one-way valve 13 is arranged between the upper driving chamber and middle driving chamber and the upper buffering chamber and middle buffering chamber, and a second one-way valve 14 is arranged between the upper driving chamber and the lower buffering chamber. The buffering piston 2 is provided with a buffering groove, and a buffering spring 4 is arranged below the buffering piston 2. In this embodiment, both variable valve lift and timing and good seating buffering effect can be achieved using only one reversing valve 24 and a motor, and the air valve piston 7 can achieve the duration at the maximum lift by shielding the lift control oil holes 23.

[0041] In this embodiment, the valve sleeve 8 is provided with a fan-shaped ring groove 20, and a one-way oil inlet 21, and the fan-shaped ring groove 20 and the one-way oil inlet 21 communicate with the lower driving chamber. An outer side of the cylinder body 1 is provided with an extension block 9, and the extension block 9 is provided with a third one-way valve. The third one-way valve communicates with the medium-pressure oil rail 27, and medium-pressure oil, after passing through the third one-way valve, enters the lower driving chamber through the fan-shaped ring groove 20 and the one-way oil inlet 21. In order to make oil flow normal at the beginning of seating, oil pressure circuits for the lower driving chamber and the lower buffering chamber are established as shown in FIG. 8. When the buffering piston 2 begins to ascend, the medium-pressure oil enters the lower buffering chamber through the oblique oil passage 15 and the second one-way valve 14. When the air valve piston 7 begins to ascend, the medium-pressure oil enters the lower driving chamber through the one-way valve on the outer side of the extension block, as well as the fanshaped annular groove 20 and the one-way oil inlet 21 on the valve sleeve, thus achieving normal fallback of the air valve piston 7.

[0042] The valve sleeve 8 is connected to a worm gear 10, and the worm gear 10 is meshed with a worm 11. The worm 11 is driven by a motor, so as to drive the worm gear 10 to rotate. A rotary valve sleeve 8 is connected by a key groove to achieve the switching between the lift control oil hole 23 on the valve sleeve 8 and an oil passage on a left side leading to the lower buffering chamber, thus changing a position of completely covering the oil hole when the air valve piston 7 has the maximum lift, and achieving lift transformation.

[0043] The cylinder body 1 is provided with a separation block 3, a sealing block 6 is arranged at the bottom of the separation block 3, an adjusting knob 5 is arranged at the bottom of the separation block 3, and is arranged on the sealing block 6. The adjusting knob 5 is in contact with one end of 24 10 24 the buffering spring 4. An effective mode of the buffering piston 2 is essentially the change of force balance caused by pressure change, so the buffering effect of the buffering piston 2 can be effectively changed by the adjusting knob 5 by changing the preload of the buffering spring 4 at zero displacement moment of the buffering piston 2.

[0044] The buffering groove is of a stepped groove structure, as shown in FIG. 12, and a flow area of the stepped groove decreases from top to bottom. During high lift, the upper buffering chamber is in a high pressure, and the buffering piston 2 is at a lower position, so the flow area is greater, and the buffering effect is smaller. With the ascending of the piston, the oil pressure in each of the upper driving chamber and the upper buffering chamber drops, and the buffering piston 2 ascends accordingly, so the flow area is reduced, and the buffering effect is enhanced gradually. When the valve is about to be seated, the effective flow area of the buffering piston 2 begins to decrease rapidly with the decrease of the lift due to the action of the stepped groove, thus achieving the buffering effect of seating. The lift of the buffering piston is shown in FIG. 11.

[0045] The buffering piston 2 can achieve force balance under the joint action of the buffering spring 4, the oil pressure in the upper buffering chamber, and the oil pressure in the lower buffering chamber. The movement of the buffering piston 2 is achieved by converting a pressure change signal of the upper driving chamber into partial stress change on the buffering piston, and the seating buffering is achieved under the joint action of the buffering groove.

[0046] Each of the first one-way valve 13 and the second one-way valve 14 is a built-in structure, and a flow rate of the first one-way valve 13 is greater than that of the second one-way valve 14. Through the design of the built-in one-way valve and an oil circuit of the cylinder body 1 and the valve sleeve 8, the functions of normal fallback and buffering of the buffering piston 2 and the air valve piston 7 are ensured, and the space occupation is reduced.

[0047] An actuation method for the electro-hydraulic variable valve actuator above specifically includes the following steps:

[0048] When a valve is opening, a reversing valve 24 is connected to a high-pressure oil rail 26, and high-pressure oil flows from a lift control oil hole 23 and a driving inner ring groove 18 to a middle driving chamber and enters an upper driving chamber and an upper buffering chamber through a first one-way valve 13. The high-pressure oil in the upper driving chamber and the high-pressure oil in the upper buffering chamber respectively push an air valve piston 7 and a buffering piston 2 to descend, as shown in FIG. 5. When the buffering piston 2 descends, hydraulic oil in a lower buffering chamber flows to a medium-pressure oil rail 27 through a medium-pressure oil port 16, and when the air valve piston 7 descends, hydraulic oil in a lower driving chamber enters 24 10 24 an oblique oil passage 15 through a radial oil flow port 22, enters the lower buffering chamber through a second one-way valve 14, and finally flows to the medium-pressure oil rail 27.

[0049] When a lower edge of the buffering piston 2 descends to completely cover the mediumpressure oil port 16, the buffering piston 2 is about to compress the hydraulic oil if continuing to descend, so the buffering piston 2 stops moving after covering the medium-pressure oil port 16 of the lower chamber. In a similar way, when a lower edge of the air valve piston 7 descends to completely shield the lift control oil hole 23, the air valve piston 7 stops moving, as shown in FIG. 6.

[0050] It should be noted that the piston movement is stopped by shielding the oil port. Based on the volume of a hydraulic oil chamber, the oil pressure of the hydraulic oil may fluctuate to some extent, making the valve have a continuous jitter of 0.2 mm at the maximum lift, as shown in FIG. 10, which is acceptable for the valve train.

[0051] When the valve begins to fall back, the reversing valve 24 is connected to a low-pressure oil rail 25, the high-pressure oil in the upper driving chamber and the high-pressure oil in the upper buffering chamber flow to a control oil port 19 corresponding to a middle driving chamber only through a buffering groove on the buffering piston 2 due to the influence of the first one-way valve 13, as shown in FIG. 7. When the air valve begins to fall back, the upper buffering chamber is in a high-pressure state, and the buffering piston 2 is at a lower position at the moment. When the hydraulic oil flows to the control oil port 19 through the buffering groove, oil pressure in the upper buffering chamber begins to drop, and the buffering piston 2 is pushed upwards under the action of the buffering spring 4 and the medium-pressure oil pressure, which makes a flow area of the buffering groove reduced to further limit an outflow speed of the high-pressure oil, thereby achieving the purpose of reducing a seating speed and achieving buffering effect of seating.

[0052] The buffering groove is of a stepped groove structure, as shown in FIG. 12, and a flow area of the stepped groove decreases from top to bottom. During high lift, the upper buffering chamber is in a high pressure, and the buffering piston 2 is at a lower position, so the flow area is greater, and the buffering effect is smaller. With the ascending of the piston, the oil pressure in each of the upper driving chamber and the upper buffering chamber drops, and the buffering piston 2 ascends accordingly, so the flow area is reduced, and the buffering effect is enhanced gradually. When the valve is about to be seated, the effective flow area of the buffering piston 2 begins to decrease rapidly with the decrease of the lift due to the action of the stepped groove, thus achieving the buffering effect of seating. The lift of the buffering piston is shown in FIG. 11.

[0053] As a mode of shielding the oil port is adopted in lift control, in order to make oil flow 24 10 24 normal at the beginning of seating, oil pressure circuits for the lower driving chamber and the lower buffering chamber are established as shown in FIG. 8. When the buffering piston 2 begins to ascend, the medium-pressure oil enters the lower buffering chamber through the oblique oil passage 15 and the second one-way valve 14. When the air valve piston 7 begins to ascend, the medium-pressure oil enters the lower driving chamber through the one-way valve on the outer side of the extension block, as well as the fan-shaped annular groove 20 and the one-way oil inlet 21 on the valve sleeve, thus achieving normal fallback of the air valve piston 7.

[0054] The worm 11 is driven by the motor, so as to drive the worm gear 10 to rotate. A rotary valve sleeve 8 is connected by a key groove to achieve the switching between the lift control oil hole 23 on the valve sleeve 8 and an oil passage on a left side leading to the lower buffering chamber, as shown in FIG. 4, thus changing a position of completely covering the oil hole when the air valve piston 7 has the maximum lift, and achieving lift transformation. During the lift transformation, in order to guarantee the normal oil inlet of the lower driving chamber, the fanshaped ring groove 20 and the one-way oil inlet 21 as shown in FIG. 13 are machined at corresponding positions of the valve sleeve.

[0055] The embodiments of the present disclosure disclosed above are only used to help explain the present disclosure. The embodiments do not exhaustively describe all the details, nor do they limit the scope of the present disclosure. Many modifications and changes can be made according to the content of the specification. These embodiments are selected and specifically described in the specification to better explain the principles and practical applications of the present disclosure, so that those skilled in the art can understand and make good use of the present disclosure.

Claims

24 10 241. An electro-hydraulic variable valve actuator capable of achieving seating buffering, comprising an upper driving chamber, a middle driving chamber, a lower driving chamber, an upper buffering chamber, a middle buffering chamber, and a lower buffering chamber, wherein the upper driving chamber is composed of a cylinder body (1), an upper end face of a valve sleeve (8), and an air valve piston (7); the middle driving chamber is composed of an inner surface of the valve sleeve (8), and an upper end of the air valve piston (7); the lower driving chamber is composed of a lower end of the air valve piston (7), the inner surface of the valve sleeve (8), and an upper end face of a cylinder head (12); the upper buffering chamber is composed of the cylinder body (1), and an upper end face of a buffering piston (2); the middle buffering chamber is composed of a buffering inner ring groove (17), and a side face of the buffering piston (2); the lower buffering chamber is composed of the cylinder body (1), and a lower end face of the buffering piston (2); the cylinder body (1) is provided with a medium-pressure oil port (16) at the lower buffering chamber, and the medium-pressure oil port (16) is able to be shielded by the buffering piston (2); the cylinder body (1) is provided with an oblique oil passage (15) communicating with the medium-pressure oil port (16), and the medium-pressure oil port (16) and the lower driving chamber both communicate with a medium-pressure oil rail (27); the cylinder body (1) is provided with a driving inner ring groove (18) and a control oil port (19) at the middle driving chamber, the control oil port (19) is connected to a reversing valve (24) through a pipeline, and the reversing valve (24) is connected to a low-pressure oil rail (25), and a high-pressure oil rail (26); the valve sleeve (8) is provided with a radial oil flow port (22) at the middle driving chamber, and the radial oil flow port (22) communicates with the driving inner ring groove (18); the valve sleeve (8) is provided with a plurality of lift control oil holes (23) at the lower driving chamber, and the plurality of lift control oil holes (23) are arranged in an axial direction of the valve sleeve (8), and are able to be shielded by the air valve piston (7); a first one-way valve (13) is arranged between the upper driving chamber and middle driving chamber and the upper buffering chamber and middle buffering chamber, and a second one-way valve (14) is arranged between the upper driving chamber and the lower buffering chamber; and the buffering piston (2) is provided with a buffering groove, and a buffering spring (4) is arranged below the buffering piston (2).

2. The electro-hydraulic variable valve actuator capable of achieving seating buffering24 10 24according to claim 1, wherein the valve sleeve (8) is provided with a fan-shaped ring groove (20) and a one-way oil inlet (21), and the fan-shaped ring groove (20) and the one-way oil inlet (21) communicate with the lower driving chamber.

3. The electro-hydraulic variable valve actuator capable of achieving seating buffering according to claim 2, wherein an outer side of the cylinder body (1) is provided with an extension block (9), the extension block (9) is provided with a third one-way valve, the third one-way valve communicates with the medium-pressure oil rail (27), and medium-pressure oil, after passing through the third one-way valve, enters the lower driving chamber through the fan-shaped ring groove (20) and the one-way oil inlet (21).

4. The electro-hydraulic variable valve actuator capable of achieving seating buffering according to claim 1, wherein the valve sleeve (8) is connected to a worm gear (10), and the worm gear (10) is meshed with a worm (11).

5. The electro-hydraulic variable valve actuator capable of achieving seating buffering according to claim 1, wherein the cylinder body (1) is provided with a separation block (3), a bottom of the separation block (3) is provided with an adjusting knob (5), and the adjusting knob (5) is in contact with one end of the buffering spring (4).

6. The electro-hydraulic variable valve actuator capable of achieving seating buffering according to claim 5, wherein the bottom of the separation block (3) is provided with a sealing block (6), and the adjusting knob is arranged on the sealing block (6).

7. The electro-hydraulic variable valve actuator capable of achieving seating buffering according to claim 1, wherein the buffering groove is of a stepped groove structure, and a flow area of the stepped groove gradually decreases from top to bottom.

8. The electro-hydraulic variable valve actuator capable of achieving seating buffering according to claim 1, wherein each of the first one-way valve (13) and the second one-way valve (14) is a built-in structure, and a flow rate of the first one-way valve (13) is greater than that of the second one-way valve (14).

9. An actuation method for the electro-hydraulic variable valve actuator according to any one of claims 1 to 8, comprising the following steps:when a valve is opening, connecting a reversing valve (24) to a high-pressure oil rail (26), and enabling high-pressure oil to flow from a lift control oil hole (23) and a driving inner ring groove (18) to a middle driving chamber and to enter an upper driving chamber and an upper buffering chamber through a first one-way valve (13), wherein the high-pressure oil in the upper24 10 24driving chamber and the high-pressure oil in the upper buffering chamber respectively push an air valve piston (7) and a buffering piston (2) to descend, when the buffering piston (2) descends, hydraulic oil in a lower buffering chamber flows to a medium-pressure oil rail (27) through a medium-pressure oil port (16), and when the air valve piston (7) descends, hydraulic oil in a lower driving chamber enters an oblique oil passage (15) through a radial oil flow port (22), enters the lower buffering chamber through a second one-way valve (14), and finally flows to the mediumpressure oil rail (27); when a lower edge of the buffering piston (2) descends to completely cover the medium-pressure oil port (16), the buffering piston (2) stops moving, and when a lower edge of the air valve piston (7) descends to completely cover the lift control oil hole (23), the air valve piston (7) stops moving;when the valve begins to fall back, connecting the reversing valve (24) to a low-pressure oil rail (25), enabling the high-pressure oil in the upper driving chamber and the high-pressure oil in the upper buffering chamber to flow to a control oil port (19) corresponding to a middle driving chamber only through a buffering groove on the buffering piston (2) due to the influence of the first one-way valve (13), wherein when the air valve begins to fall back, the upper buffering chamber is in a high-pressure state, and the buffering piston (2) is at a lower position at the moment, and when the hydraulic oil flows to the control oil port (19) through the buffering groove, oil pressure in the upper buffering chamber begins to drop, and the buffering piston (2) is pushed upwards under the action of the buffering spring (4) and the medium-pressure oil pressure, which makes a flow area of the buffering groove reduced to further limit an outflow speed of the high-pressure oil, thereby achieving the purpose of reducing a seating speed and achieving buffering effect of seating.

10. The actuation method for the electro-hydraulic variable valve actuator according to claim 9, wherein a worm (11) is driven by a motor to drive a worm gear (10) to rotate, a rotary valve sleeve (8) is connected through a key groove to achieve the switching between the lift control oil hole (23) on the valve sleeve (8) and an oil passage on a left side leading to the lower buffering chamber, thus changing a position of completely covering the oil hole when the air valve piston (7) has the maximum lift, and achieving lift transformation.

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