FI124349B

FI124349B - Hydraulic actuator and throttle valve arrangement

Info

Publication number: FI124349B
Application number: FI20125254A
Authority: FI
Inventors: Saku Niinikangas; Magnus Sundsten
Original assignee: Wärtsilä Finland Oy
Priority date: 2012-03-09
Filing date: 2012-03-09
Publication date: 2014-07-15
Also published as: KR102032010B1; KR20140140571A; FI20125254A; CN104160119B; CN104160119A; EP2834480B1; EP2834480A1; WO2013132149A1

Description

Hydraulic actuator and gas exchange valve arrangement Technical field of the invention

The present invention relates to a hydraulic actuator for opening a gas exchange valve of an internal combustion engine according to the preamble of claim 1. The invention 5 also concerns a gas exchange valve arrangement in accordance with the other independent claim.

Background of the invention

In large internal combustion engines, such as in ship or power plant engines, the gas ex-10 change valves can be either mechanically or hydraulically actuated. The most conventional way to operate the intake and exhaust valves is to use cam-driven valve opening mechanisms, where the valves are opened by the lobe of a rotating cam and closed by valve springs. These kinds of arrangements are reliable, but also inflexible. Valve timing is difficult to adjust and if variable valve closing or opening timing is needed, valve 15 mechanisms become complicated. In an electro-hydraulic systems valve timing can be changed easily. However, the flexibility is often achieved at the cost of reduced reliability.

Summary of the invention 20 An object of the present invention is to provide an improved hydraulic actuator for opening a gas exchange valve of an internal combustion engine. The characterizing fea-^ tures of the actuator according to the present invention are given in the characterizing

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^ part of claim 1. Another object of the invention is to provide an improved gas exchange ^ valve arrangement. The characterizing features of the gas exchange valve arrangement ° 25 according to the invention are given in the characterizing part of the other independent cc “ claim.

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The hydraulic actuator according to the invention comprises a pressurizing chamber for o ^ pressurizing hydraulic fluid, a drive piston that is arranged in the pressurizing chamber 30 and which drive piston divides the pressurizing chamber into at least one input portion 2 and at least one output portion, an inlet duct for introducing pressurized hydraulic fluid into the input portion of the pressurizing chamber for moving the drive piston, a fluid outlet for supplying hydraulic fluid from the output portion of the pressurizing chamber to the gas exchange valve, and an outlet duct for releasing hydraulic fluid from the input 5 portion of the pressurizing chamber. The actuator further comprises a hydraulic valve having a first position, in which position flow from the inlet duct to the input portion of the pressurizing chamber is allowed and flow from the input portion to the outlet duct is prevented, and a second position, in which position flow from the inlet duct to the input portion of the pressurizing chamber is prevented and flow from the input portion to the 10 outlet duct is allowed.

The gas exchange valve arrangement according to the invention comprises at least one gas exchange valve for opening and closing flow communication between a gas exchange duct and a cylinder of the engine, the gas exchange valve comprising a valve 15 head and a valve stem, a receiving chamber, a driven piston that is in mechanical connection with the valve stem and arranged in the receiving chamber, and a hydraulic actuator defined above.

With the hydraulic actuator and the gas exchange valve arrangement according to the 20 invention, the number of electrical components in the gas exchange valve actuating me chanism can be minimized. The actuator and the arrangement thus combine the reliability of a mechanical valve opening system and the flexibility of an electro-hydraulic system. Since the valve lift is limited by the stroke of the drive piston, too high valve lifts are prevented.

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οό According to an embodiment of the invention, the actuator comprises a control valve for o g actuating the hydraulic valve.

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According to another embodiment of the invention, the drive piston divides the output oj 30 side of the pressurizing chamber into a first output portion that is provided with a first ^ fluid outlet and into a second output portion that is provided with a second fluid outlet.

0X1 Each of the fluid outlets can be used for supplying hydraulic fluid to one gas exchange valve. This guarantees simultaneous opening of both gas exchange valves.

3

According to another embodiment of the invention, the output portion end of the drive piston is formed of a solid cylindrical part and the input portion end of the drive piston is formed of a hollow cylindrical part that comprises at least one opening in the sleeve 5 for allowing flow into and out of the input portion of the pressurizing chamber. The opening can comprise a groove that is arranged around the outer circumference of the hollow cylindrical part and a boring connecting the groove to the space defined by the hollow cylindrical part. Because of the groove, flow into the input portion of the pressurizing chamber or out of it is allowed in any angular position of the drive piston.

10

According to another embodiment of the invention, the actuator comprises means for throttling the flow into the input portion of the pressurizing chamber and/or out of the input portion at the beginning and/or at the end of the movement of the drive piston. When the flow into and out of the input portion of the pressurizing chamber is limited, 15 smooth acceleration and deceleration of the drive piston is ensured. The throttling effect can be achieved by arranging the opening of the piston to be only partially aligned with the end of an intermediate duct connecting the input portion of the pressurizing chamber to the hydraulic valve when the drive piston is at the input portion end and/or at the output portion end of the pressurizing chamber.

20

According to another embodiment of the invention, the inlet duct and the outlet duct are provided with adjustable throttles for regulating flow rates in the ducts. With adjustable throttles, gas exchange valve opening and closing speeds can be changed.

C\l o 25 According to another embodiment of the invention, the actuator comprises a second co drive piston that has a larger diameter and a shorter stroke than the first drive piston and o σ> which second drive piston is arranged in the input portion of the pressurizing chamber 0 1 for assisting the first drive piston at the beginning of the pressurizing stroke. With the

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second drive piston, the needed hydraulic pressure is lower and energy can be saved.

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£ According to another embodiment of the invention, a fluid chamber that is in fluid ^ communication with the inlet duct is arranged at one end of the spindle of the hydraulic valve, and a control valve is arranged to release pressure from the fluid chamber for ac- 4 tuating the hydraulic valve. No external fluid supply duct is thus needed for actuating the hydraulic valve.

According to an embodiment of the invention, the gas exchange valve arrangement is 5 provided with a pressure accumulator that is connected to the outlet duct for recovering energy from the outlet duct, and to the inlet duct for supplying energy into the inlet duct.

According to an embodiment of the invention, the driven piston is arranged around the 10 valve stem. This saves space compared to a construction where the driven piston is arranged at the end of the valve stem.

Brief description of the drawings

Fig. 1 shows a gas exchange valve arrangement according to an embodiment of the in-15 vention.

Fig. 2 shows the arrangement of Fig. 1 with open gas exchange valves.

Fig. 3 shows a gas exchange valve arrangement according to a second embodiment of the invention.

Fig. 4 shows a gas exchange valve arrangement according to a third embodiment of the 20 invention.

Fig. 5 shows a gas exchange valve arrangement according to a fourth embodiment of the invention.

Fig. 6 shows a gas exchange valve arrangement according to a fifth embodiment of the ^ invention, o . 25 Fig. 7 shows part of a valve actuator according to an embodiment of the invention, o

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0 1 Detailed description of the invention g Embodiments of the invention are now described in more detail with reference to the

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accompanying drawings.

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The hydraulic actuator and the gas exchange valve arrangement according to the invention can be used in large internal combustion engines, such as in main or auxiliary en- 5 gines of ships or in engines that are used at power plants for producing electricity. The arrangement comprises at least one gas exchange valve 1, Γ, which opens and closes flow communication between a gas exchange duct 2 and a cylinder of the engine. The gas exchange valves 1,1’ can be either intake valves or exhaust valves, and the gas ex-5 change duct 2 is thus either an intake duct or an exhaust duct. In the embodiments shown in the accompanying figures, the arrangement comprises a first gas exchange valve 1 and a second gas exchange valve Γ. In an engine, in which the arrangement is used, each cylinder of the engine is provided with a gas exchange valve arrangement according to the invention. Preferably, there is a similar arrangement for both the intake 10 valves and the exhaust valves. The gas exchange valves 1, 1 ’ are arranged in the cylinder head 4 of the respective cylinder. Each gas exchange valve 1, Γ comprises a valve stem lb, lb’ and a valve head la, la’. The valve head la, la’ co-operates with a corresponding valve seat Id, Id’. A valve spring 16,16’ is arranged around the valve stem lb, lb’ of each gas exchange valve 1, Γ for closing the gas exchange valve 1,1’. The cy-15 finder head 4 is provided with valve guides 17, 17’ for accommodating the gas exchange valves 1, Γ.

The gas exchange valves 1, Γ are electro-hydraulically operated. For operating the gas exchange valves 1,1’, each gas exchange valve arrangement comprises a hydraulic ac-20 tuator 35. The hydraulic actuator 35 comprises a pressurizing chamber 9, in which a drive piston 7 is arranged. The drive piston 7 divides the pressurizing chamber 9 into at least one input portion 9a and at least one output portion 9b. In the embodiment of the figures, the pressurizing chamber 9 is divided into one input portion 9a and into a first and a second output portion 9b, 9b’. The drive piston 7 can reciprocate in the pressuriz-

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o 25 ing chamber 9. When pressure medium is introduced into the input portion 9a of the cö pressurizing chamber 9, the drive piston 7 pressurizes hydraulic fluid on the output side o cd 9b, 9b’ of the pressurizing chamber 9. A returning spring 18 is arranged in the pressu- 0 1 rizing chamber 9 for pushing the drive piston 7 towards the input portion 9a of the pres-

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surizing chamber 9. However, the return stroke of the drive piston 7 could also be im-oj 30 plemented by introducing hydraulic fluid into the output portion 9b of the pressurizing ^ chamber 9. The hydraulic actuator 35 comprises a hydraulic valve 10 for opening and

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closing flow communication between a pressure source, such as a hydraulic pump 12, and the input portion 9a of the pressurizing chamber 9. The hydraulic valve 10 also pre- 6 vents and allows outflow from the input portion 9a of the pressurizing chamber 9. The hydraulic valve 10 is arranged between a hydraulic pump 12 and the input portion 9a of the pressurizing chamber 9. In a first position of the hydraulic valve 10, flow from an inlet duct 15 into the input portion 9a of the pressurizing chamber 9 is allowed and flow 5 from the input portion 9a into an outlet duct 21 is prevented, as shown in figure 2. In a second position of the hydraulic valve 10, flow from the inlet duct 15 into the input portion 9a of the pressurizing chamber 9 is prevented and flow from the input portion 9a into the outlet duct 21 is allowed, as shown in figure 1. The same hydraulic valve 10 is thus used for controlling valve opening and closing timing of both gas exchange valves 10 1, Γ. The hydraulic actuator 35 further comprises fluid outlets 9d, 9d’ for supplying hy draulic fluid from the output portions 9b, 9b’ of the pressurizing chamber 9 to the gas exchange valves 1,1’.

A driven piston lc, lc’ is arranged in mechanical connection with the valve stem lb, 15 lb’ of each gas exchange valve 1,1’. The gas exchange valve 1, Γ is thus moved together with the driven piston lc, lc’. The driven piston lc, lc’ is arranged in a receiving chamber 5,5’ that is in fluid communication with the output portion 9b, 9b’ of the pressurizing chamber 9. The first output portion 9b of the pressurizing chamber 9 is connected with a first connecting duct 6 to the receiving chamber 5 of the first gas ex-20 change valve 1, and the second output portion 9b’ of the pressurizing chamber 9 is connected with a second connecting duct 6’ to the receiving chamber 5’ of the second gas exchange valve Γ. Since the hydraulic actuator 35 is provided with an own output portion 9b, 9b’ for each of the gas exchange valves 1, Γ, the pressurized hydraulic fluid is supplied simultaneously to both of the gas exchange valves 1, 1 ’.

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cb When hydraulic fluid is introduced into the input portion 9a of the pressurizing chamber g 9, the drive piston 7 moves and pressurizes hydraulic fluid in the output portions 9b, 9b’ x of the pressurizing chamber 9. From the output portions 9b, 9b’ of the pressurizing chamber 9, the hydraulic fluid flows into the receiving chambers 5, 5’ and the gas ex-oj 30 change valves 1, 1 ’ are opened. When hydraulic fluid is released from the input portion g 9a of the pressurizing chamber 9, the drive piston 7 can be moved backwards by the re-

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turning spring 18. Hydraulic fluid can thus flow from the receiving chambers 5, 5’ back 7 into the output portions 9b, 9b’ of the pressurizing chamber 9 and the gas exchange valves 1,1’ can be closed by the valve springs 16, 16’.

In the embodiment of figures 1 and 2, an intermediate duct 20 is arranged between the 5 hydraulic valve 10 and the pressurizing chamber 9 for connecting the input portion 9a of the pressurizing chamber 9 to the hydraulic valve 10. The hydraulic valve 10 is a hydraulically actuated slide valve. The hydraulic valve 10 is a three-way valve that comprises a first port 10a that is connected to the inlet duct 15, a second port 10b that is connected to the outlet duct 21, and a third port 10c that is connected to the intermediate 10 duct 20. The hydraulic valve 10 comprises a spindle 22 that has a first position and a second position. In the first position of the spindle 22, flow communication between the first port 10a and the third port 10c is closed and flow communication between the second port 10b and the third port 10c is open. Hydraulic fluid can thus flow from the inlet duct 15 into the intermediate duct 20, but flow from the intermediate duct 20 into 15 the outlet duct 21 is prevented. In the second position of the spindle 22, flow communication between the first port 10a and the third port 10c is open and the flow communication between the second port 10b and the third port 10c is closed. Hydraulic fluid can thus flow from the intermediate duct 20 into the outlet duct 21, but flow from the inlet duct 15 into the intermediate duct 20 is prevented. The hydraulic valve 10 is provided 20 with a spring 19 that keeps the spindle 22 in the first position when the hydraulic valve 10 is not actuated. When an external force is applied to the spindle 22, the spindle 22 is moved to the second position. For applying the force on the spindle 22, the hydraulic actuator 35 is provided with a control valve 11. The control valve 11 is a hydraulic valve that is operated with a solenoid. The control valve 11 could also be some other

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o 25 kind of electrically actuated valve. When the control valve 11 is in the position of figure cb 2, hydraulic fluid is introduced onto a pressure surface 23 of the spindle 22 for moving o cd the spindle 22. In the embodiment of figures 1 and 2, the receiving chamber 5, 5’ is ar cs x ranged around the valve stem lb, lb’ and the driven piston lc, lc’ is a projection of the Q_ valve stem lb, lb’. This arrangement enables compact design of the cylinder head 4.

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£ The output portion end of the drive piston 7 is formed a solid cylindrical part 7b and the ^ input portion end of the drive piston 7 is formed of a hollow cylindrical part 7a. The in put portion end of the solid cylinder 7b forms a surface onto which the pressure of the 8 hydraulic fluid is applied. The hydraulic fluid is introduced into the input portion 9a of the pressurizing chamber 9 through the sleeve of the hollow cylinder 7a. The sleeve is therefore provided with at least one opening, which consists of a groove 13a and a drilling 13b. In the embodiment of the figures, two drillings 13b are in connection with the 5 groove 13a. Because of the groove 13a that is arranged around the whole outer circumference of the hollow cylinder, flow through the drillings 13b is allowed in any angular position of the drive piston 7. The groove 13a widens towards the outer surface of the hollow cylinder and is only partially aligned with the intermediate duct 20 when the drive piston 7 is at the input portion end of the pressurizing chamber 9. Therefore, the 10 flow into the input portion 9a of the pressurizing chamber 9 is throttled when the hydraulic valve 10 is moved into the second position and fluid supply from the hydraulic pump 12 into the pressurizing chamber 9 is allowed. Consequently, the drive piston 7 accelerates smoothly. When the drive piston 7 moves forward, the groove 13a becomes fully aligned with the intermediate duct 20 and maximum flow into the input portion 9a 15 of the pressurizing chamber 9 is allowed. When the drive piston 7 approaches the output portion end of the pressurizing chamber 9, the groove 13a becomes again partly overlapping with the walls of the pressurizing chamber 9. The flow into the input portion 9a of the pressurizing chamber 9 is thus limited and the drive piston 7 slows down. The movement of the drive piston 7 in the opposite direction works in a similar way. Since 20 the outflow from the input portion 9a of the pressurizing chamber 9 is throttled at the beginning and at the end of the movement of the drive piston 7, both the acceleration and deceleration of the drive piston 7 is smooth.

There are also other ways for achieving the throttling effect. In figure 7 is shown part of

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o 25 a valve actuator 35, where the opening of the drive piston is a straight drilling 13b. The οό intermediate duct 20 between the hydraulic valve 10 and the input portion 9a of the σ> pressurizing chamber 9 is connected to a groove 13c that encircles the inner surface of o x the pressurizing chamber 9. When the drive piston 7 is at the output portion end of the

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pressurizing chamber 9, as shown in figure 7, or at the input portion end of the pressu-oj 30 rizing chamber 9, the drilling 13b of the drive piston 7 is only partially aligned with the £· groove 13c of the input portion 9a of the pressurizing chamber 9. The flow out of the

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input portion 9a of the pressurizing chamber 9 or into it is thus throttled. The groove 9 13c is chamfered so that the flow area is very small at the beginning and at the end of the movement of the drive piston 7.

The drive piston 7 further comprises a boring 39, which connects the input portion 9a of 5 the pressurizing chamber 9 to the output portion 9b. A second boring 40 connects the input portion 9a to the second output portion 9b’. Through the borings 39, 40, leakages from the output side of the valve actuator 35 can be compensated. The diameters of the borings 39, 40 are small, and flow through the borings 39, 40 does thus not disturb the functioning of the hydraulic actuator 35. The input portion 9a and the output portions 10 9b, 9b’ of the pressurizing chamber 9 are also provided with air removal ports 41, 42, 43 for removing air from the hydraulic system. The diameters of the air removal ports 41, 42, 43 are small for preventing excessive leakage of the hydraulic fluid. The air removal ports 41, 42, 43 can also be provided with throttles 41a, 42a, 43a for reducing leaking of the hydraulic fluid, as shown in figure 4.

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The embodiment shown in figure 3 differs from the embodiment of figures 1 and 2 in terms of the construction of the hydraulic valve 10. The hydraulic valve 10 of figure 3 comprises a fourth port lOd. The hydraulic actuator 35 comprises a first intermediate duct 20 and a second intermediate duct 28. The first port 10a of the hydraulic valve 10 20 is connected to the inlet duct 15 and the third port 10c is connected to the first intermediate duct 20. The second port 10b is connected to the outlet duct 21 and the fourth port lOd is connected to the second intermediate duct 28. In the first position of the hydraulic valve 10, the spindle 22 allows flow from the inlet duct 15 into the first intermediate duct 20 and prevents flow from the second intermediate duct 28 into the outlet duct 21.

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o 25 In the second position of the hydraulic valve 10, the spindle 22 allows flow from the co second intermediate duct 28 into the outlet duct 21 and prevents flow from the inlet duct g 15 into the second intermediate duct 28. Hydraulic fluid is introduced into the input por- x tion 9a of the pressurizing chamber 9 through the first intermediate duct 20. The hy-

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draulic fluid is released from the input portion 9a of the pressurizing chamber 9 through oj 30 the second intermediate duct 28. In the embodiment of figure 3, separate fluid supply to ^ the control valve 11 is not needed. The inlet duct 15 is connected with a control duct 26 o

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to a fluid chamber 27 that is arranged at one end of the spindle 22. Together with the spring 19 of the hydraulic valve 10, the pressure in the fluid chamber 27 keeps the hy 10 draulic valve 10 in the first position, when the control valve 11 is closed. When the control valve 11 is opened, hydraulic fluid is released from the fluid chamber 27 and the hydraulic valve 10 is switched into the second position. In the embodiment of figure 3, the driven piston lc, lc’ is arranged at the end of the valve stem lb, lb’.

5

In the embodiment of figure 4, the hydraulic valve 10 is identical to the hydraulic valve 10 of figure 3. In this embodiment, the first and the second intermediate ducts 20, 28 are merged into a combined intermediate duct 36 before the pressurizing chamber 9. A third intermediate duct 37 and a fourth intermediate duct 38 are branched from the combined 10 intermediate duct 36 and connected to the input portion 9a of the pressurizing chamber 9. The diameters of the third intermediate duct 37 and the fourth intermediate duct 38 are smaller than the diameter of the combined intermediate duct 36. The third and the fourth intermediate ducts 37, 38 are provided with check valves 24, 25. Through the third intermediate duct 37, flow from the combined intermediate duct 36 into the pres-15 surizing chamber 9 is allowed. The third intermediate duct 37 is located so that when the drive piston 7 is at the input portion end of the pressurizing chamber 9, the groove 13a of the drive piston 7 is aligned with the end of the third intermediate duct 37 and direct flow from the combined intermediate duct 36 into the pressurizing chamber 9 is prevented. Through the fourth intermediate duct 38, flow from the pressurizing chamber 20 9 into the combined intermediate duct 36 is allowed. The fourth intermediate duct 38 is located so that when the drive piston 7 is at the output portion end of the pressurizing chamber 9, the opening 13a of the drive piston 7 is aligned with the fourth intermediate duct 38 and direct flow from the pressurizing chamber 9 into the combined intermediate duct 36 is prevented. Flow speed is thus restricted at the beginning and at the end of the

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δ 25 stroke of the drive piston 7 and smooth acceleration and deceleration is achieved. In the

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g embodiment of figure 4, the inlet duct 15 is provided with an adjustable throttle 30. Al- g so the outlet duct 21 is provided with an adjustable throttle 31. With the throttles 30,31, x the flow in the inlet duct 15 and the outlet duct 21 can be restricted and the opening and closing curves of the gas exchange valves 1, Γ can be affected. Smaller flow gives cm 30 slower gas exchange valve opening/closing and faster flow gives quicker open- g ing/closing. The input portion 9a of the pressurizing chamber 9 is provided with a

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second drive piston 7’. The second drive piston 7’ has larger diameter and a shorter stroke than the first drive piston 7. Since the second drive piston 7’ assists the first drive 11 piston 7, smaller hydraulic pressure is needed at the beginning of the stroke of the first drive piston 7. Smaller hydraulic pressure decreases energy consumption of the arrangement.

5 The embodiment of figure 5 differs from the embodiment of figure 4 in that the arrangement is provided with a pressure accumulator 32 for energy recovery. The pressure accumulator 32 is connected to the outlet duct 21 upstream from the throttle 31. The pressure accumulator 32 is also connected to the inlet duct 15 upstream from the throttle 30 and downstream from the hydraulic pump 12 and the pressure accumulator 10 32. A second hydraulic pump 12b is arranged downstream from the hydraulic pump 12 and from the pressure accumulator 32 A check valve 33 is arranged between the pressure accumulator 32 and the outlet duct 21 for preventing flow from the first hydraulic pump 12 or the pressure accumulator 32 into the outlet duct 21. During the backwards stroke of the drive piston 7, energy can be recovered from the outlet duct 21 into the 15 pressure accumulator 32. The first hydraulic pump 12 supplies hydraulic fluid at a smaller pressure level than is needed for operating the drive piston 7. The pressure of the flow from the first hydraulic pump 12 and from the pressure accumulator 32 is raised to the sufficient level by the second hydraulic pump 12b.

20 In the embodiment of figure 6, the hydraulic valve 10 is a solenoid valve. Since the flow capacity of a single solenoid valve is small, the arrangement is provided with a second solenoid valve 10b that is arranged in parallel with the first solenoid valve 10. The valves 10, 10b could also be other electrically actuated valves.

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o 25 It will be appreciated by a person skilled in the art that the invention is not limited to the

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cb embodiments described above, but may vary within the scope of the appended claims.

o σ> For instance, it is possible to combine features of the different embodiments.

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Claims

A hydraulic actuator (35) for opening the gas exchange valve (1, Γ) of an internal combustion engine, the hydraulic actuator (35) comprising: a pressurizing chamber (9) for pressurizing the hydraulic fluid, a 5. operating piston (7) arranged in the pressurizing chamber (7) dividing the pressure chamber (9) into at least one inlet portion (9a) and at least one outlet portion (9b), - an inlet channel (15) for supplying pressurized hydraulic fluid to the inlet portion (9a) of the pressure chamber (9) , 10. a fluid outlet (9d) for supplying hydraulic fluid from the outlet section (9b) of the pressurizing chamber (9) to the gas exchange valve (1, Γ), having a first position in which the flow from the inlet channel (15) to the inlet section (9a) of the pressure chamber (9) is allowed and the flow from the inlet section (9a) to the outlet section (21) is blocked, and a position in which the flow from the inlet channel (15) to the inlet section (9a) of the pressure chamber (9) is prevented from flowing from the inlet section (9a) into the outlet channel (21), characterized in that the actuator (35) comprises a second drive piston (7 ') having a larger diameter 20 and a shorter stroke than the first actuator piston (7), and the second actuation piston (7 ') is provided at the inlet portion (9a) of the pressure chamber (9) to assist in the first actuation piston (7).

Actuator (35) according to claim 1, characterized in that the actuator (25) comprises a control valve (11) for actuating the hydraulic valve (10),

3. An actuator according to claim 1 or claim 2 (35), characterized in that the used-cc tömäntä (7) divides the pressure chamber (9) in the first fluidinpoistoau-Ln glycol discharge side (9d) with a first outlet portion (9b) and the second fluidinpoistoaukolla LO C 30 (9d ') provided with a second discharge section (9b'). δ c \ j

Actuator (35) according to one of Claims 1 to 3, characterized in that the actuator (35) comprises means for restricting the flow into and / or out of the inlet part (9a) of the pressurizing chamber (9). at the beginning and / or end of the movement. 5

Actuator (35) according to one of the preceding claims, characterized in that the end of the outlet side of the drive piston (7) is formed by a solid cylindrical part (7b) and the inlet end of the drive piston (7) is formed by a hollow cylindrical part (7a) having at least one opening (13a, 13b) in its jacket to allow flow into and out of the inlet (9a) of the pressure chamber (9).

Actuator (35) according to claim 5, characterized in that the opening (13a, 13b) comprises a groove (13a) arranged around the circumference of the hollow cylindrical part (7a) and a hole (13b) connecting the hollow cylindrical part (13a). 7a) to confine the space. 15

Actuator (35) according to claim 5 or 6, characterized in that the opening (13a, 13b) in the housing of the drive piston (7) widens towards the outer surface of the housing.

Actuator (35) according to one of Claims 5 to 7, characterized in that the opening (13a, 13b) in the housing of the drive piston (7) is only partially aligned with the intermediate channel connecting the inlet part (9a) of the pressure chamber (9). (20, 28) with the head when the drive piston (7) is at the inlet end of the pressure chamber (9). co δ 25

Actuator (35) according to one of Claims 5 to 8, characterized in that the opening (13a, 13b) in the housing of the CM 4 drive piston (7) is only partially aligned with the end of the 8 channel (20 '28>). , δ (7) is at the pressure end of the "buzzer0" <9> x at the outlet end. □ _ cm 30 10. An actuator (35) according to any one of the preceding claims, characterized in that the inlet channel (15) and the outlet channel (21) provided with adjustable chokes 00 (30, 31) for controlling flow rates in the channels (15, 21).

10 Ib '), - a receiving chamber (5, 5'), and - a piston (le, le ') to be used which is in mechanical engagement with the valve stem (Ib) and is arranged in the receiving chamber (5, 5'), characterized in that a hydraulic actuator (35) according to any one of claims 1 to 11.

Actuator (35) according to one of the preceding claims, characterized in that the fluid chamber (27) in fluid communication with the inlet channel (15) is arranged at one end of the spindle (22) of the hydraulic valve (10) and the control valve (11) 27) for actuating the hydraulic valve (10). 5

A gas exchange valve arrangement for an internal combustion engine comprising at least one gas exchange valve (1, Γ) for opening and closing the flow connection between the gas exchange channel (2) and the engine cylinder, the gas exchange valve (1, Γ) comprising a valve disc (lail, la ') (Ib,

An arrangement according to claim 12, characterized in that the arrangement is provided with a pressure accumulator (32) connected to an outlet channel (21) for recovering energy from the outlet channel (21) and an inlet channel (15) for supplying energy to the inlet channel 20 (15).

Arrangement according to Claim 12 or 13, characterized in that the piston (le, le ') to be used is arranged around the valve stem (Ib, Ib'). co δ c \ j o O) C \ l X cc CL ln CM m CM δ CM