JP2013204586A - Gas exchange valve for combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas exchange valve for a combustion engine, configured to prevent abrasion and noise due to impact hitting of a valve stem top part when closing a valve.SOLUTION: A gas exchange valve includes a spindle hole, a stored valve spindle 10, a shock absorbing chamber, and a variable volume valve operation chamber arranged in an upper part of the spindle hole. The valve spindle 10 is provided with: an upper end 11 provided with a shock absorbing means 32 constituted so as to interlock with the shock absorbing chamber for damping the movement of the valve spindle 10 in a valve closing process of an exhaust valve; a shaft A in the longitudinal direction; a compensating member 30 arranged on the upper end 11, and slidable between a pushing-in position and an extension position along the shaft A in the longitudinal direction; and a spring 40. A compensating chamber 50 arranged in an upper part of the spindle, is in permanent fluid communication with the variable volume valve operation chamber, via an opening part 70 formed so as to pass through an upper surface 31 of the compensating member 30.

Description

  The present invention relates to a self-adjustable shock absorber for an exhaust valve top actuator for a large two-stroke diesel engine.

  In crosshead large two-stroke diesel engines, the exhaust valves are correspondingly larger, and in some engines the height is about 2 meters. In such large structures, the effect of material temperature has a non-negligible effect on the dimensions of the structure that can affect the function of the structure. As a result, the temperature of the valve spindle and valve housing of the exhaust valve affects the length of the valve spindle. The length of the valve spindle then affects the precision of the valve operation. The exhaust valve is equipped with means for buffering the final movement of the valve spindle while the exhaust valve is closed, and such means are often provided at the top of the valve spindle. These buffering means are intended to prevent or reduce wear and noise caused by the abutment of the stop surfaces provided on the top of the spindle and on the housing and by the abutment between the valve and the valve seat. Provided. If the valve spindle becomes too long due to temperature dependent expansion, the valve will not fit closely with the valve seat and there is a risk of causing leakage from the combustion chamber. In addition, the top of the valve stem can strike the top of the valve stem hole, causing increased wear and noise problems. If the valve is too short, the valve closing buffer will not function correctly, wear on the valve and valve seat will increase, and this bang will cause noise problems.

  The temperature of the engine changes, for example due to differences in engine load conditions, especially during startup when the engine gradually transitions from a cold state to an operating temperature.

  Due to such temperature differences within the engine, the exhaust valve spindle expands and contracts and expands and contracts at a different speed than the housing in which the spindle is mounted. The larger the engine, the larger the exhaust valve and the larger the valve spindle. Accordingly, the expansion and contraction of the valve spindle is also large and can affect the operating condition of the exhaust valve, as explained above. The length of the exhaust valve spindle is adapted to the main operating conditions of the engine. Therefore, in large engines, the exhaust valve must be allowed to operate in a sub-optimal manner during certain engine operating conditions (temperatures) or certain measures to compensate for spindle length differences. Can be taken. Such a measure is usually in the form of a complex system that is arranged at the junction of the valve stem or in connection with a valve closing buffer (shut-off) mechanism, which is arranged at the top of the valve spindle. There are many. Such mechanisms use ball valves and bellows that can easily fail and require maintenance at short intervals, as well as several pressure chambers of different pressures that require separate sources, and can be complex in construction. Many. Also known in the art are various spring mechanisms for adjusting the length of the stem. Such a mechanism is not adjustable without active control. Examples of these can be found in US20060283411, FR2647570, and DE19529155. US20060283411 discloses a gas exchange valve according to the preamble of claim 1.

  Based on this background art, an object of the present invention is to provide an exhaust valve having a spindle in which the overall length of the spindle can be adjusted automatically and passively. It is also an object of the present invention to provide a simple, virtually maintenance-free mechanism for automatically and passively adjusting the length of the valve stem.

This object is achieved by providing a gas exchange valve for the combustion engine as follows. This gas exchange valve
・ Spindle hole,
A valve spindle housed in the spindle hole;
A buffer chamber;
A variable volume valve operating chamber disposed above the spindle hole;
The valve spindle is
An upper end provided with buffer means configured to interlock with the buffer chamber for buffering movement of the valve spindle during the closing process of the exhaust valve;
A longitudinal axis;
A compensation member provided at the upper end and slidable between a pushed position and an extended position along the longitudinal axis;
A spring for urging the compensating member toward the extended position;
A compensation chamber is disposed at the top of the spindle;
The compensation chamber and the variable volume valve operating chamber disposed above the spindle hole are connected so that fluid can always go back and forth through an opening formed so as to penetrate the upper surface of the compensation member.

  It would be advantageous to use such a gas exchange valve as an exhaust valve. Further, such a gas exchange valve is particularly useful for a crosshead type low speed large two stroke uniflow type diesel engine.

  In one embodiment, the compensation chamber has a maximum volume, the opening has a size and shape, the spring applies a predetermined upward force on the compensation member, the volume of the compensation chamber, the volume Providing a tight fit of the buffer means configured such that the shape and size of the opening, and the upward force of the spring, interlock with the buffer chamber in response to a temperature change of the gas exchange valve Configured to do.

  In a further embodiment, the compensation chamber is at least disposed between the compensation member and the upper end of the spindle.

  In a further embodiment, the compensation member is received in a first hole provided in the upper end and is open towards the upper end of the spindle.

  In a further embodiment, the compensation chamber is at least partially disposed within the compensation member.

  In a further embodiment, the compensation chamber comprises a portion formed by a hole formed in the compensation member and a volume formed between the compensation member and the hole in the spindle.

  In a further embodiment, the portion of the compensation chamber in the compensation member comprises a first hole portion and a second hole portion, wherein the first hole portion is larger than the second hole portion. Has an area.

  In a further embodiment, the spring is disposed in the first hole portion.

  In any of the above embodiments, the compensation chamber may further include a second hole formed in the spindle, wherein the second hole is in fluid communication with the first hole of the spindle. .

  In any of the above embodiments, the buffer means may be further provided on the top of the compensation member.

  In a further embodiment, at least one passage is provided to provide a continuous flow of fluid between the buffer chamber and the top of the spindle hole.

  In any of the above embodiments, the variable volume valve actuation chamber may have a portion defining a buffer chamber formed in a top closure and having a portion open in the top portion of the spindle hole. Good.

  In any of the above embodiments, the buffer chamber may communicate with a control valve for supplying pressurized hydraulic fluid to the variable volume valve actuation chamber.

  In any of the above embodiments, the gas exchange valve is an exhaust valve (1) for the crosshead large low speed two-stroke uniflow diesel engine.

  Further objects, features, advantages and characteristics of the exhaust valve according to the present invention will become apparent from the detailed description.

In the following detailed portion of the description, the present invention will be described in greater detail with reference to the exemplary embodiments shown in the drawings.
The cross-sectional view shows the upper part of the crosshead large two-stroke uniflow diesel engine. An exhaust valve according to the invention is shown by a cross-sectional view. A cross-sectional view shows details of the upper part of the exhaust valve in FIG. 4 shows a spindle telescopic mechanism according to the present invention in which a compensation member is formed on the exhaust valve in FIGS. 5A to 5C show the spindle telescopic mechanism of FIG. 4 at various positions with respect to the upper end of the spindle, according to cross-sectional views. FIG. 5A shows a state where the compensation member is in the most extended position. The state which has a compensation member in an intermediate position is shown. The state which exists in the position where the compensation member was most pushed in is shown. The upper part of the valve spindle with the compensation member according to the invention is shown by a partially transparent perspective view. The cross-sectional view shows an embodiment of the opening in the compensation member. A cross-sectional view shows another embodiment of the opening in the compensation member. A sectional view shows another embodiment of the spindle telescopic mechanism. In the graph, a simulation of the movement of the compensation member according to the invention is shown. The cross-sectional view shows an alternative embodiment of the top of the spindle where the compensation member is configured to fit over the top of the spindle. Details of the upper part of the exhaust valve are shown, illustrating the connection between the buffer chamber and the top of the spindle hole.

Detailed Description of the Preferred Embodiment

  In the following, a detailed description of an exhaust valve according to the invention will be described by means of a preferred embodiment.

  FIG. 1 shows a uniflow type cylinder 100 used in a crosshead large low speed two-stroke uniflow type diesel engine. A crosshead large low speed two-stroke uniflow diesel engine typically has 3 to 14 such cylinders. The cylinder 100 has a scavenging port 102 located in the air box 103, which is supplied with pressurized scavenging, for example by a turbocharger, from a scavenging receiver (not shown).

  The exhaust valve 1 is mounted centrally at the top of the cylinder in the cylinder cover 124 '. At the end of the expansion stroke, the exhaust valve 1 opens before the engine piston 105 passes down past the scavenging port 102, so that the combustion gases in the combustion chamber 106 above the piston 105 open into the exhaust receiver 108. It flows out through the exhaust passage 107. The exhaust valve 1 closes again during the upward movement of the piston 105 at an adjustable moment, which may depend, for example, on the desired effective compression ratio for the next combustion. During the closing operation, the exhaust valve 1 is driven upward by the air spring 123 (away from the combustion chamber 106).

  The exhaust valve 1 is opened by an actuator 109 driven by hydraulic pressure. Hydraulic fluid, such as hydraulic oil, is supplied through a pressure conduit 110 that connects a port 80 on the actuator 109 (see FIGS. 2-4) with a control port on the top surface of the distributor block 112 supported by the console 113. Is done. The distributor block 112 is connected to a high-pressure conduit 114 for hydraulic fluid supplied from a common rail (not shown), for example at a pressure which can be in the range from 200 bar to 500 bar, preferably 300 bar. Is done. The common rail may also function as a source of high pressure fluid for the fuel injection system.

  The hydraulic fluid in the common rail may be used to drive the valve actuator directly or indirectly via a pressure amplifier / separator that isolates the hydraulic fluid for the valve actuator 109 from the hydraulic fuel in the common rail. In that case, the hydraulic fuel may be, for example, fuel oil. The pressure in a common rail fuel system varies depending on engine operating conditions such as operating speed and load conditions. Typically, the pressure in a common rail fuel system for a large two-stroke diesel engine varies between 800 and 2000 bar.

  If a dedicated common rail for the valve actuator 109 is used, hydraulic fluid can be supplied from a storage tank (not shown) through a pumping station (not shown), for example, standard hydraulic oil Preferably, however, engine lubricating oil is used as the hydraulic fluid and the system is supplied from the engine sump.

  The internal combustion engine may be a medium speed 4 stroke diesel or gas engine, or a low speed 2 stroke crosshead diesel engine, which may be a propulsion engine in a ship or an installed prime mover in a power plant.

  Each cylinder 100 of the engine is an electronic control unit 115 that receives general synchronization and control signals through electrical wires 116 (or wirelessly) and transmits electronic control signals to the control valve 117, in particular, through electrical wires 118. 115 may be associated. There may be one control unit 115 per cylinder, or several cylinders may be associated with the same control unit 115. The control unit 115 may also receive signals from a general control unit common to all cylinders.

  Alternatively (not shown), the exhaust valve 1 and / or the control valve 117 may be controlled by a cam, ie mechanical hydraulic control.

  The control valve 117 may be of any ordinary type. The structure and operation of control valve 117 are well known per se and should not require further explanation in this context.

  When the exhaust valve 1 is opened, a control signal from the control unit 115 actuates the control valve 117 so that high pressure fluid freely enters the pressure conduit 110 and thus the fluid supply port 80 (FIG. 3). When the exhaust valve 1 is closed, the control valve 117 is actuated so that the high pressure in the conduit 110 is discharged to the return conduit 122. As a result, the air spring 123 pushes the exhaust valve toward the closed position of the valve.

  FIG. 2 shows an exhaust valve 1 according to the invention. The exhaust valve 1 is of a type used for a crosshead type large-scale low speed, two-stroke uniflow type diesel engine as shown in FIG.

  The exhaust valve 1 comprises a spindle (or stem) 10 that stands upright from the valve disk 3 and has a bottom or lower end or portion 12, an upper end 11 and a central portion 13. The spindle 10 is elongated and has a longitudinal axis B. The spindle 10 is slidably received in the spindle hole 5.

  The central portion 13 of the spindle 10 supports a spring piston 125 that is firmly mounted on the spindle 10 so as to seal the pressure in the air cylinder 126 and to be longitudinally displaceable. Below the spring piston 125 is a spring chamber 127 connected through a suitable valve 156 to a supply of pressurized air (not shown), which valve 156 is at a predetermined minimum pressure, for example 4.5 bar. Maintain a spring chamber 127 filled with pressurized air at an overpressure of. Other air pressures may also be used, such as from 3 bar to 10 bar. The minimum pressure is selected according to the desired spring characteristics of the air spring 123. Although it is possible to connect spring chambers 127 on several different cylinders to each other, it is preferred that each spring chamber be individually shut off by a check valve in the supply of pressurized air. Pressurized air in the spring chamber 127 creates a sustained upward force on the spring piston 125 and consequently on the spindle 10. The valve disc 3 is thus continuously propelled towards the valve seat 4, i.e. in the upward direction. The upward force increases when the spring piston 125 is displaced downward by the valve actuator 109 (see below) and compresses the air in the spring chamber 127 that is prevented from flowing out by the check valve 156.

  The housing 128 defines a cavity 129 around and above the spring piston 125 of the air spring 123. Cavity 129 is connected to a drain (not shown) so that the cavity above the spring piston has atmospheric pressure and hydraulic oil leaking from the hydraulic actuator 109 above the air spring can be drained.

  The hydraulic actuator 109 is comprised of a cylinder 131 supported by the top of the housing 128, or, as shown, the cylinder 131 and the housing 128 are formed of one integral part.

  In FIG. 2, the valve disc 3 is shown in a closed position where the valve disc 3 abuts against the valve seat 4. In the drawing, the valve disc is further illustrated in an open position where the valve disc has moved away from the valve seat 4. The valve disc 3 'in the open position is indicated by a contour drawn with dots.

  The upper part 11 of the spindle 10 is accommodated in a central hole 6 (see, for example, FIG. 3) in the cylinder 131, and the central hole 6 forms the upper part of the spindle hole 5. The central hole 6 is closed at the top of the cylinder 131 by a top closure 132 and opens to the bottom of the cylinder 131. The central hole 6 is arranged coaxially with the spindle hole 5 in the housing 128.

  3 and 4, the central hole 6 is divided into coaxial parts having different diameters (or cross-sectional areas). That is, the top 6 ′ has the largest diameter, the middle 6 ″ has the middle diameter, and the bottom 6 ′ ″ has the narrowest diameter of the three. A first upward shelf-like projection 7 is formed between the uppermost part 6 ′ and the middle part 6 ″. A second upward shelf-like protrusion 8 is formed between the middle part 6 ″ and the lowermost part 6 ′ ″.

  The piston 90 is slidably disposed in the central hole 6 (forming the upper part of the spindle hole 5). The piston 90 has a cylindrical main portion 91 and a collar portion 92 disposed on the top of the main portion 91. The piston 90 has a central hole 90 ′ configured to slidably receive the upper portion 11 of the spindle 10. The collar portion 92 has a larger diameter (or cross-sectional area) than the main portion 91. The maximum diameter of the main part 91 is adapted to a minute gap that is slidably arranged in the middle part 6 '' of the central hole. The maximum diameter of the collar portion 92 is adapted to a minute gap that is slidably disposed on the uppermost portion 6 ′. The collar is also cylindrical or ring shaped so that the collar has an opening that communicates with the central hole 90 ′ of the main portion 91 of the piston 90. The downward internal shelf-like protrusion 93 is formed between the collar portion 92 and the main portion 91 in the central hole 90 ′ of the piston 90. The inner shelf projection 93 is configured to engage the upper annular surface 15 of the spindle 10 or at least the outer portion of the annular surface 15. The piston 90 further has an upward upper surface 94 formed on the collar portion 92. This upper surface 94 on the collar 92 is ring-shaped like the upper annular surface 15 of the spindle 10. However, the surface area of the upper surface 94 is significantly larger than the area of the upper annular surface 15 of the spindle 10. Accordingly, the surface area of the upper surface 94 may be 2 to 10 times larger than the area of the upper annular surface 15 of the spindle 10. A downward external shelf projection 95 is formed between the collar 92 and the main portion 91 on the outer surface of the piston 90. The main portion 91 further has a lower surface 96. The lower surface 96 is ring-shaped or annular.

  A buffer chamber 81 is formed in the top closure 132. The buffer chamber is open in the uppermost part 6 ′ of the central hole 6, ie in the uppermost part of the spindle hole 5.

  The piston 90 may slide relative to the upper part 11 of the spindle 10 and relative to the parts 6 ′ and 6 ″ of the central hole 6, as explained above.

  The variable volume valve actuation chamber 60 includes an upper portion 6 ′ of the central bore 6, a downward surface 132 ′ of the top closure 132, a buffer chamber 81, an upward top surface of the piston 90, and an upper portion 11 of the spindle 10 and an upper portion of the spindle 10. 11 and a compensation member 30 disposed in the first hole 20 disposed in the first hole 20 (see further below).

  The hydraulic fluid is supplied to and released from the variable volume valve actuation chamber of the valve actuator 109 via a port 80 (see FIG. 3) where the fluid connects to the pressure conduit 110. The port 80 passes through a chamber 65 formed as an expanded portion of the spindle hole 5, a port 83 formed in the chamber 65, a conduit 85 communicating with the chamber 65, and a port 82 forming an inlet to the buffer chamber 81. A fluid is connected to the variable volume valve actuation chamber. The pressure conduit 110 is not shown in FIGS. Thereby, the port 80 is connected to the buffer chamber 81, which opens into the central hole 6 in the cylinder 131.

  Via pressure conduit 110, port 80 is alternately connected to a high pressure source (high pressure conduit 114) and return conduit 122. See FIG.

  Thus, the variable volume valve actuation chamber 60 is connected via the port 82 in the buffer chamber 81 via the conduit 85 and the port 83 to the second pressure chamber 65, which is connected to the central bore 6. The lowermost part 6 ′ ″, the part 11 ′ of the upper part 11 of the spindle 10 and the first unfolded part 65 ′, the second unfolded part 65 ″ of the central hole 6 and the unfolding of the upper part 11 of the spindle 10 Defined with the portion 16 formed.

  If the exhaust valve is opened after combustion in the combustion chamber 106, the pressure in the combustion chamber is very high. Thus, a large force is required to open the exhaust valve 1 during the initial downward movement of the valve disc 3 and the valve spindle 10. Piston 90 assists in this initial stage by increasing the effective area of the pressure surface of valve actuator 109 as described below.

  In order to open the exhaust valve 1, the control valve 117 supplies high pressure fluid to the port 80. The hydraulic fluid pressurizes the variable volume valve actuation chamber 60 and the second pressure chamber 65, where the hydraulic fluid acts on the upward ledge 16 ′ on the unfolded portion 16 of the spindle 10. To do. One or more gaps or passages 39 allow hydraulic fluid to pass continuously between the buffer chamber 81 and the top 6 ′ of the hole 6. Thereby, the variable volume valve actuation chamber 60 is initially constituted by a buffer chamber 81 and a part of the top 6 ′ of the hole 6. Incoming hydraulic fluid flows into the spindle 10, i.e., the upper surface 94 of the piston 90, the upper annular surface 15, and the upper surface 31 of the upper portion 11 of the spindle 10 (the upper surface 31 on the sliding portion 30 described in more detail below. Act on). The downward internal shelf-like protrusion 93 abuts on a part of the upper annular surface 15 of the spindle 10. This pushes the spindle 10 and the piston 90 downward.

  A groove 99 formed as an elongated indentation in the hole top 6 ″ of the central hole 6 and parallel to the elongated axis B, allows hydraulic fluid to flow between the space above the piston 90 and the space below the piston 90. Give a passage. When the piston 90 is pushed downward (area 95 is smaller than area 94), the hydraulic fluid passes from below the piston 90 upward. The groove or grooves 99 terminate the upper separation of the shelf-like protrusion 7 formed between the uppermost part 6 ′ and the middle part 6 ″ of the central hole 6. When the downwardly facing outer ledge 95 of the piston 90 passes through the bottom of the groove or grooves 99, hydraulic fluid is prevented from passing from the space below the piston 90 to the space above. This will cause an increase in pressure in the space below the piston 90, which will slow down the downward movement of the piston 90 and eventually stop.

  Therefore, after moving the distance in the downward direction, the downward external shelf-like projection 95 of the piston 90 has a downward external shelf-like projection 95 between the uppermost portion 6 ′ and the middle portion 6 ″ of the central hole 6. Before coming into contact with the upward shelf-like projection 7, it arrives and stops. While the downward movement of the piston 90 is stopped, the spindle 10 continues its downward movement and pressure still acts on the upper annular surface 15 and on the upper surface 31 of the upper part 11 of the spindle 10. .

  Thus, the piston 90 provides a larger area for the pressure in the variable volume valve actuation chamber 60 to act while the exhaust valve is open. Once the valve disk 3 has been moved away from the valve seat 4, the pressure in the combustion chamber 106 is reduced by the combustion gases leaving the chamber 106 via the exhaust conduit 107. Thus, a much smaller force is required to keep the exhaust valve moving in the downward direction to fully open than during the initial opening. Thus, after the piston 90 is stopped, the pressure in the variable volume valve actuation chamber 60 will only act on the upper annular surface 15 and the upper surface 31 of the upper portion 11 of the spindle 10. Thereby, the spindle 10 has its spindle 10 until the brake bump shelf 17 (see FIG. 4) on the spindle 10 passes the lower edge of the second widened portion 65 ″ of the central hole 6. Will continue to exercise downward. The spindle 10 begins to decelerate and eventually stops because the top 11 of the spindle 10 breaks the connection to the port 80 and because the pressure no longer increases in the variable volume chamber 60.

  When the combustion chamber 106 is evacuated to initiate closure of the exhaust valve 1, the control valve 117 connects the pressure conduit 110 to the return conduit 122 and hydraulic fluid is allowed to flow back through the port 80. . The air spring 123 will push the spindle 10 upward, thereby starting to pressurize the hydraulic fluid in the variable volume valve actuation chamber 60 through the second pressure chamber 65.

  As the spindle 10 moves upward, the upper annular surface 15 of the spindle 10 finally abuts against the downwardly facing inner shelf projection 93 of the piston 90 and the rest below that piston 90 (the outer shelf of the piston 90). The piston 90 is pushed together with the spindle 10 so that the protrusion 95 moves in an upward direction between the upper portion 6 ′ and the middle 6 ″ of the central hole 6 and close to the upward shelf-like protrusion 7). become.

  The upward movement is braked and finally stopped when the buffering means in the form of a conical surface 32 at the top of the upper part 11 (on the compensation member 30) of the spindle 10 enters the buffering chamber 81. Thus, the passage between the buffer chamber 81 and the uppermost part 6 'of the central hole is gradually reduced. Thereby, when the conical surface 32 enters the buffer chamber 81, the pressure increases at the top 6 ′ of the central bore 6, ie in the variable volume valve actuation chamber 60, so that the upward movement of the spindle is The upper annular surface 33 of the top 10 of the ten is buffered until it gently abuts on the downwardly facing surface 132 ′ of the top closure 132. The upper annular surface 33 faces upward and is formed on the sliding portion below the upper surface 31 and the conical surface 32.

  A set of vanes 14 (FIG. 2) on a portion of the valve spindle 10 located in the exhaust conduit 107 is used when the exhaust gas flows through the exhaust conduit 107, i.e. when the exhaust valve 1 is open. Push 10 and rotate. Thereby, the spindle 10 will rotate at least slightly each time the exhaust valve is opened. Thereby, smoother wear of the contact disk-like protrusions of the valve disc 3, the valve seat 4 and the spindle 10 and the spindle hole 5 is ensured.

  The air spring 123 may be returned by the return stroke pressure chamber and the piston surface area that drives the spindle 10 to the retracted position. This embodiment (not shown) will require a slightly modified control valve that can supply pressurized hydraulic fluid to the pressure return stroke chamber to propel the piston to the retracted position. The same principle as above can be used to control the pressure in the return stroke pressure chamber with respect to the position of the first piston.

  5A-5C, the upper portion 11 of the spindle 10 includes a mechanism for adjusting the length of the spindle 10, which is also illustrated in the previous drawings. This mechanism comprises a compensation member 30 arranged in a first hole 20 in the upper part 11 of the spindle 10, which first hole 20 opens towards the upper end of the spindle 10 and the annular surface 15. The first hole 20 has a longitudinal axis A that is coaxial with the longitudinal axis B of the spindle 10. The compensation member 30 is slidably received in the first hole 20 so that the compensation member can slide relative to the spindle 10 in a direction parallel to the longitudinal axis A.

  The compensation member 30 is preferably circular in cross section and has an elongated cylindrical shape. The compensation member 30 has an upward upper surface 31 and a downward lower surface 34. The compensation member 30 has a length in the longitudinal direction of the compensation member that is longer than the length of the hole 20 in which the compensation member 30 is accommodated. Accordingly, a part of the compensation member 30 always extends above the upper annular surface 15 of the spindle 10 and forms an extension of the compensation member 30.

  The compensation member 30 has a hole 35. The hole 35 has an upper part 35 ′ and a lower part 35 ″. The upper part 35 'has a certain diameter or cross-sectional area and the lower part 35' 'has a certain diameter or cross-sectional area. The diameter or cross-sectional area of the upper part 35 ′ is smaller than the diameter or cross-sectional area of the lower part 35 ″. A downward shelf-like projection 36 is formed between the upper part 35 'and the lower part 35' '.

  The upper part 30 ′ and the lower part 30 ′ ″ of the compensation member 30 have a diameter or cross-sectional area corresponding to the diameter or cross-sectional area of the first hole 20 in the spindle 10. Accordingly, the compensation member 30 is received in the first hole 20 with a small gap, and therefore, along the longitudinal axis A, as shown in FIG. 5C, as shown in FIG. 5C. Slidable between various extended positions.

  Compensation member 30 is biased by spring 40 toward an extended or upward position, ie, downward surface 132 ′ of top closure 132. The spring 40 has an upper end 41 and a lower end 42. The spring 40 is arranged in the lower part 35 ″ of the hole 35 in the compensation member 30 and is guided by the lower part 35 ″. The upper end 41 of the spring 40 abuts on the shelf-like protrusion 36, and the lower end 42 is adjacent to the bottom surface 22 of the first hole 20 in the spindle 10. As shown in FIG. 5A, the lower end 41 of the spring 40 may be fixed to the recess 22 ′ in the bottom surface 22 of the first hole 20 in the spindle 10.

  The compensation member 30 further includes a middle portion 30 ''. The middle portion 30 ″ has a diameter smaller than the diameter of the upper portion 30 ′ of the compensation member 30 and smaller than the lower portion 30 ′ ″. Accordingly, the middle portion 30 ″ forms a recess with respect to the upper portion 30 ′ and the lower portion 30 ′ ″ of the compensation member 30. The detent or screw 200 secures the compensation member 30 in the first hole 20 by reciprocal relation with the recess formed by the middle portion 30 ″. An upward ledge 37 formed between the middle portion 30 ″ and the lower portion 30 ′ ″ of the compensation member 30 is provided on the detent or screw 200 to define the uppermost position of the compensation member 30 in the hole 20. It will abut against. Thereby, the compensation member 30 is prevented from being pushed out of the first hole 20 in the spindle 10 by the spring 40. The detent is disposed in a hole 201 formed perpendicular to the elongated axis B of the exhaust valve 1 in the upper part 11 of the spindle 10, as shown in the see-through view in FIG. Accordingly, the detent or screw 200 may be removed from the channel 201, allowing the compensation member 30 to be removed from the hole 20 for repair.

  In the embodiment of the compensation member 30 shown in FIGS. 5A-5C, a second hole 25 is further formed in the spindle 10 that extends coaxially with the first hole 20 and has a first Extends downward from the bottom 22 of the bore 20 or from the recess 22 '.

  The upper part 30 ′ of the compensation member is preferably provided with the above arrangement for buffering the movement of the valve spindle during the closing process of the exhaust valve in the form of a conical part 32.

  Thereby, the compensation chamber 50 is defined in the compensation member 30 and between the compensation member 30 and the hole 20 and the second hole 25 in the upper part 11 of the spindle 10. Accordingly, in the embodiment shown in FIGS. 2-6, the compensation chamber 50 includes an upper portion 35 ′ and a lower portion 35 ″ of the hole 35, a downwardly lower surface 34 of the compensation member 30, and a bottom 22 of the hole 20 in the spindle 10. It is formed by the space 21 between them and the second hole 25.

  Between the compensation chamber 50 and the variable volume valve actuation chamber 60 (see, for example, FIG. 4), fluid can pass back and forth through an opening 70 formed to penetrate the upper surface 31 of the compensation member 30. Since there is fluid communication through the opening 70 between the variable volume valve actuation chamber 60 and the compensation chamber 50, as long as the pressure differential is between the variable volume valve actuation chamber 60 and the compensation chamber 50, the hydraulic fluid Will be between the two chambers 50,60. Thus, the pressure differential will result in a longitudinal translation of the compensation member within the bore 20 in the spindle, thereby leading to an increase or decrease in the overall spindle length. The pressure in the variable volume valve actuation chamber 60 and the compensation chamber 50 is, of course, mainly determined by the pressure of the hydraulic fluid injected into the variable volume valve actuation chamber 60 through the port 80. However, the pressure also depends on the size of the chamber, which further depends on the temperature of the spindle 10, the compensation member 30, and the cylinder 131 (including the top closure 132). There are temperature differences in the parts described, from the cold (non-operating) state of the engine to the state where the engine is running under normal operating conditions (due to friction between engine parts and combustion of fuel in the combustion chamber). In large two-stroke engines used on ships, the period of time before the engine reaches the normal operating temperature of the engine may be from about 30 minutes to one and a half hours. There is also a (smaller) temperature difference between high and low load operation of the engine. These temperature differences, among other things, make a difference in the length of the spindle 10 (which can be from 0.5 m to 2 m in a large two-stroke engine of the kind described above).

  Accurately balancing the stretch of the compensation member balances the spring force that pushes the compensation member upward, the size of the opening 70 (which determines the speed of the hydraulic fluid flow), and the size of the compensation chamber 50. Is made by

  In FIG. 5A, the compensation member 30 is shown in a fully extended position. This position corresponds to a situation where the engine is cold and therefore the spindle 10 is relatively short. FIG. 5C represents a situation where the engine is running at full load, the spindle 10 is heated and is at the expected maximum length. During normal operation, the compensation member 30 will be in a position between the two extreme positions, as shown in FIG. 5B. However, as described below, the above position should be understood as the average position for each temperature scenario, so the compensation member 30 will change position with each stroke of the engine piston 105. .

  Simulations and experiments show an appropriate relationship between spring force, opening size, and the total volume of the compensation chamber 50. In the following, an example is given for a cylinder engine of 50 cm (inner hole), in which the diameter of the spindle hole 5 is 52 mm (see, for example, in FIG. 4, part 6 ′ ″).

  The pressure applied to actuate the exhaust valve is raised to about 300 bar in the variable volume valve actuation chamber 60.

  The spring 40 preferably provides an upward force on the compensation member 30 equal to a 0.2-1.5 bar pressure difference between the variable volume valve actuation chamber 60 and the compensation chamber 50. Preferably, the spring 40 provides an upward force on the compensation member 30 equal to 0.5 bar.

  The opening preferably has a diameter in the range of 0.2-1 mm, preferably 0.5 mm.

The volume of the compensation chamber 50 is preferably a 20.000~25000mm ³ (volume mm), for example, when the compensating member is in the fully extended position is 22,453Mm ³ and the like.

  Similar values can be calculated or found by experiment or simulation for other cylinder sizes, valve spindle hole diameters, and exhaust valve operating pressures.

  Thereby, the compensation member 30 automatically ensures that the position of the conical surface 32 and the upward shelf projection 33 form a precise fit with the buffer chamber 81 and the surface 132 'of the top closure 132, respectively. Make a guarantee. That is, the overall length of the spindle 10 including the compensation member 30 is always adapted to ensure that the buffering mechanism at the top of the spindle 10 is always in the correct position relative to the buffer chamber 81, and the exhaust valve. One valve disc 3 is guaranteed to be in close proximity to the valve seat 4.

  In the alternative embodiment shown in FIG. 9, the compensation chamber 50 is formed in the compensation member 30 in a different manner than the embodiment shown above. Like reference numerals refer to like parts in FIGS. The compensation chamber 50 is formed by a single hole 35 in the compensation member 30 and by a space 21 between the compensation member 30 and the bottom 22 of the hole 20 in the spindle 10. The length of the hole 35 is larger than that in the above embodiment, but the upper hole 35 'and the second hole 25 in the above embodiment are omitted. Thus, the volume of the compensation chamber 50 may be selected as desired to adjust the overall length of the spindle 10 depending on the size of the engine and the speed of adjustment desired, and the spring force and aperture diameter / May be balanced with size. In other non-illustrated embodiments, the volume of the compensation chamber 50 in the embodiment of FIG. 9 may be matched with the second chamber 25 as shown in the embodiment of FIG.

  In FIG. 10, an example of simulation of compensation member extension is shown during a single engine cycle. The simulation is performed on the compensation member 30 according to the embodiment shown in FIG. 9 and using the data of the above example. In the drawing, the curve G1 shows the pressure applied to the variable volume valve actuation chamber 60. The pressure (in bar) is read on the right scale in the drawing. Curve G2 shows the corresponding displacement of the exhaust valve 1 (the distance moved by the valve disc 3 away from the valve seat 4). The distance (in mm) is read on the scale on the right side of the drawing. A curve G3 indicates the displacement of the compensation member 30 with respect to the hole 20 in the spindle 10. The distance (in mm) is read on the scale on the left side in the drawing. The scale on the abscissa is the time in seconds. The illustrated state is where the compensation member 30 is in the process of adapting the overall spindle length to the lower temperature of the spindle 10. Therefore, the position of the compensation member 10 gradually increases as time passes. During one-third of the cycle shown (in hours) (up to 0.15), the position of the compensation member gradually increases to approach the buffer chamber 81. The pressure in the variable volume valve actuation chamber 60 is at ambient pressure because the exhaust valve is closed. Next, at 0.15, the exhaust valve must be open to evacuate the combustion chamber 106. The hydraulic fluid under pressure is directed to the variable volume valve actuation chamber 60, which rapidly intensifies pushing the spindle 10 to move the valve disk 3 to push it from the valve seat 4, which The variation is given first. The pressure in the variable volume valve actuation chamber 60 is about 300 bar and the displacement of the valve is about 200 mm, eventually leveling off. The position of the compensation member 30 is pushed down into the hole 20 as a result of the rapidly increased pressure in the variable volume valve actuation chamber 60. However, once a pressure balance is achieved between the pressure in the compensation chamber 50 and the pressure in the variable volume valve actuation chamber 60, the position of the compensation member 30 is moved further back toward the extended position due to the spring force. Begin to. When the exhaust valve is closed again after evacuation of the combustion chamber 106, the pressure in the variable volume valve actuation chamber 60 is as seen by the almost instantaneous drop in curve G1 (just before time t = 0.3). Reduced. Therefore, when the pressure in the actuator 109 is interrupted, the pressure of the air spring 123 pushes the exhaust valve upward toward the closed position of the exhaust valve. As soon as the pressure in the variable volume valve actuation chamber 60 is shut off, the compensation member 30 will move more vigorously toward the extended position until the pressure in the compensation chamber 50 and variable volume valve actuation chamber 60 is again in equilibrium. . Thus, dynamic adjustment of the overall spindle length is achieved not only over various engine temperature conditions but also in each cycle of the engine.

  7 and 8 show two different embodiments of the opening 70. In the embodiment of FIG. 7, the openings are in a conical portion 71 that opens into the upper surface 31 of the compensation member 30 and in the hydraulic fluid receiving chamber 50, ie, the hole 35 or the second hole 35 ′. It has a first cylindrical part 73 and a second conical part 72 that are open. The first cylindrical portion 73 has a certain diameter. The first cylindrical portion 73 forms a minimum area passage for the opening, thereby defining the diameter (or cross-sectional area) of the opening. In the embodiment shown in FIG. 8, the opening 70 has an opening having a conical portion 71, a first cylindrical portion 73, and a second cylindrical portion 74 that are open in the upper surface 31 of the compensation member 30. Have The second cylindrical portion 74 is closer to the upper surface 31 and the cylindrical portion 73 is closer to the compensation chamber 50. In this embodiment, the first cylindrical portion opens into the hydraulic fluid receiving chamber 50, i.e. the hole 35 or the second hole 35 '. The first cylindrical portion 73 has a certain diameter. The first cylindrical portion 73 forms a minimum area passage for the opening, thereby defining the diameter (or cross-sectional area) of the opening.

  FIG. 6 shows the upper part 11 of the spindle 10, in a partially transparent perspective view, in which the compensation member 30 is arranged in a hole 20 that opens towards the upper surface 15 of the upper part 10 of the spindle 10. FIG. 6 illustrates how the compensation member 30 can be easily accessed from above, for example, to assemble and remove the spindle and compensation member 30 for repair. This is made possible by a pin 200 arranged in a hole 201 in the upper part 11 of the spindle 10, which has a longitudinal axis perpendicular to the longitudinal axis B of the spindle 10, a part of the hole 201 being The compensation member receiving hole 20 is opened in the hole 20 which opens toward the upper surface 15. Thereby, the pin 200 inserted in the hole 201 can interact with the middle part 30 ″ of the compensation member 30 and the compensation member 30 slides along the axis A of the compensation member receiving hole 20. Enabling, the ledge or upward surface 37 (between the middle 30 ″ and the lower 30 ′ ″ of the compensation member 30) thus limits the top position of the compensation member 30 relative to the spindle 10. A stop is defined with the pin.

  FIG. 6 also clearly shows how the passage 39 is formed in the upper part 30 ′ of the compensation member. The plurality of passages 39 are distributed radially around the outer periphery of the compensation member 30 and are formed as grooves in the outer surface of the middle portion 30 ″ of the compensation member 30. The groove allows the hydraulic fluid to flow between the buffer chamber 81 and the top hole / portion 6 ′ of the spindle hole 5 so that the buffer chamber 81 and the top / portion 6 ′ of the spindle hole 5 together form a variable volume working chamber 60. It is possible to pass continuously between. The passage 39 can also be understood from FIG. 12, which shows the upper part of the actuator of the hydraulic exhaust valve in which the compensation member 30 is provided at the top of the spindle 10. The arrows in the figure indicate the flow of hydraulic fluid to the variable volume working chamber 60 formed by the buffer chamber 81 and the uppermost part 6 ′ of the spindle hole 5. Hydraulic fluid enters the buffer chamber 81 from the conduit 85 via the port 82 and passes from the buffer chamber 81 via the passage 39 (groove) and into the top / portion 6 ′ of the spindle hole 5 to the variable volume working chamber 60. Pressurize. 6 and 12, the conical surface 32 (forming the buffering means including the buffer chamber 81) has a first diameter (or cross-sectional area) at the top and a second at the bottom closest to the upward annular surface 33. It will be appreciated that the first diameter is smaller than the second diameter so that the conical surface 32 tapers in an upward direction. From FIG. 12, a second smaller diameter is preferably used for the buffer chamber so that hydraulic fluid can flow into and out of the top 6 'of the spindle hole via the passage 39. It will be appreciated that the diameter is less than 81. The gap between the conical surface 32 and the second, smaller diameter buffer chamber 81 of the conical surface 32 is (the upward annular surface 33 of the compensation member 30 is the downward surface 132 ′ of the top closure 132. Preferably, it is very small. In FIG. 12, the upward annular surface 33 of the compensation member 30 abuts the downward surface 132 ′ of the top closure 132.

  The part in FIG. 12 changes the part shown in FIG. 4 by a slightly different angle. Therefore, in FIG. 4, the conduit 85 cannot be seen, and only some ports 82 between the buffer chamber 81 and the conduit 85 can be seen. In FIG. 12, a portion through two conduits 85 is shown. Thus, the two figures illustrate that there may be more than one conduit 85 connecting to the buffer chamber 81. In FIG. 3, only one is shown.

  Above, an embodiment of the spindle length adjustment mechanism has been described with respect to a spindle using a piston 90 for accelerating the movement of the spindle 10 during the initial stage of opening of the valve 1, which piston 90 is It is arranged on the top. However, it will be understood that a similar accelerating piston can be placed on another part of the spindle where the above embodiment of the spindle telescopic mechanism can still function.

  FIG. 11 shows an alternative embodiment of the spindle telescopic mechanism. The same reference numerals as used above with respect to FIGS. 1-10 are used for the same features with respect to the description of the embodiment shown in FIG. In this embodiment, the compensation member 30 is slidably disposed on the outer top of the spindle instead of being disposed in a hole in the spindle. Therefore, the compensation member 30 is a cup-shaped structure disposed on the uppermost end portion 11 of the spindle 10 and above the uppermost end portion. In order to maintain fluid communication between the variable volume valve actuation chamber 60 and the compensation chamber 50, an opening 70 is provided through the compensation member. In this embodiment, the variable volume valve actuation chamber 60 is defined by a buffer chamber 81 and an upper portion 6 ′ of the spindle hole 5. Furthermore, the compensation chamber 50 is defined by the space between the end 11 of the spindle and the downwardly facing inner wall of the compensation member, the main hole 20 and the second hole 25 provided in the spindle 10. Corresponding to the previous embodiment, the embodiment shown in FIG. 11 also has a passage (not shown) similar to the passage 39 of the previous embodiment, which passes between the buffer chamber 81 and the spindle hole 5. Provides a continuous flow of fluid to and from the top 6 '.

  In all of the above embodiments, the buffering means for buffering the valve closure is described as being in the form of a conical surface 32 provided on the compensation member 30 that interacts with the buffer chamber 81 wall. Yes. However, the conical surface may also be provided as a wall of the buffer chamber 81 and the top of the compensation member may be formed as a straight cylindrical portion. Similarly, although the passages 39 are described as being provided on the compensation member 30, these passages may also be provided in the walls of the buffer chamber 81.

  The term “comprising” as used in the claims does not exclude other elements or steps. The terms “a” or “an” as used in the claims do not exclude a plurality of states. A single processor or other unit may fulfill the functions of several means recited in the claims.

Claims (14)

A gas exchange valve (1) for a combustion engine,
The spindle hole (5),
A valve spindle (10) housed in the spindle hole (5);
A buffer chamber (81);
A variable volume valve actuation chamber (60) disposed above the spindle hole (5);
The valve spindle (10) is
A buffer means (32) configured to interlock with the buffer chamber (81) for buffering the movement of the valve spindle (10) during the closing process of the gas exchange valve (1) is provided. The upper end (11)
A longitudinal axis (A);
A compensation member (30) provided at the upper end (11), the compensation member (30) being slidable between a pushed position and an extended position along the longitudinal axis (A);
A gas exchange valve (1) comprising a spring (40) biasing the compensation member (30) towards the extended position;
A compensation chamber (50) is arranged at the top of the spindle;
The compensation chamber (50) and the variable volume valve operating chamber (60) disposed above the spindle hole (5) are formed to penetrate the upper surface (31) of the compensation member (30). Gas exchange valve (1), characterized in that it is connected in such a way that fluid can always go back and forth through the opening (70).   The compensation chamber (50) has a maximum volume, the opening has a size and shape, and the spring is configured to apply a predetermined upward force on the compensation member, the compensation chamber (50) ), The shape and size of the opening (70), and the upward force of the spring (40), the buffer chamber (1) in response to a temperature change of the gas exchange valve (1). 81. A gas exchange valve (1) according to claim 1, configured to provide a tight fit of the buffer means (32) configured to interlock with 81).   The gas exchange valve (1) according to claim 1 or 2, wherein the compensation chamber (50) is arranged at least between the compensation member (30) and the upper end of the spindle (10).   The compensation member (30) is housed in a first hole (20) provided in the upper end (11) and opens toward the upper end (11) of the spindle (10). The gas exchange valve (1) according to any one of 3 above.   The gas exchange valve (1) according to claim 4, wherein the compensation chamber (50) is at least partially disposed within the compensation member (30).   The compensation chamber (50) is formed between a portion formed by a hole (35) formed in the compensation member (30) and the hole (20) in the compensation member (30) and the spindle (10). 6. A gas exchange valve (1) according to claim 5, comprising a volume (21) formed in the.   The portion of the compensation chamber (50) in the compensation member comprises a first hole portion (35 '') and a second hole portion (35 '), the first hole portion (35') being The gas exchange valve (1) according to claim 6, having a larger cross-sectional area than the second hole portion (35 ').   The gas exchange valve (1) according to claim 7, wherein the spring (40) is arranged in the first hole portion (35 ').   The compensation chamber (50) further comprises a second hole (25) formed in the spindle (10), wherein the second hole (25) is the first hole ( The gas exchange valve (1) according to any one of claims 1 to 6, wherein a fluid flows through 20).   The said buffer means (32) is a gas exchange valve (1) as described in any one of Claims 1-9 provided in the uppermost part of the said compensation member (30).   The at least one passage (39) is provided to allow a continuous flow of fluid between the buffer chamber (81) and the top of the spindle hole (5). Gas exchange valve (1).   The variable volume valve actuating chamber (60) defines a buffer chamber (81) formed in the top closure (132) and is open at the top of the spindle hole (5). The gas exchange valve (1) according to any one of claims 1 to 11, comprising:   The gas exchange valve (1) according to claim 12, wherein the buffer chamber (81) is in communication with a control valve (117) for supplying pressurized hydraulic fluid to the variable volume valve actuation chamber (60). ).   The gas exchange valve (1) according to any one of claims 1 to 13, wherein the gas exchange valve is an exhaust valve (1) for the crosshead large low-speed two-stroke uniflow type diesel engine.

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