JP3974614B2 - Device for controlling the off-time connection between two pressure medium impact collective machines and one pressure medium source - Google Patents

Description

  The present invention relates to an apparatus for controlling an offset connection between two pressure medium impact type collective machines and one pressure medium source, and in particular, a hydraulically operated injection means for a cylinder of a two-cycle large diesel engine; The present invention relates to a device for operating a hydraulically operated discharge valve at different timings.

  In a two-cycle large diesel engine currently in practical use, two separate control valves are assigned to the injection means and the exhaust valve actuator. However, this type of valve structure with two separate control valves has been found to be expensive.

  German Patent Application No. 103 11 493.9, which has not yet been published, describes a device of the above type, in which a main control valve formed as a slide valve is provided, by means of this main control valve. The injection pump actuator and the discharge valve actuator can be connected to the pressure medium source, so that the casing of the main control valve is assigned to the actuator, side by side with the inlet connected to the intermediate pressure medium source. The two outlets are selectively connectable to the inlets by displacement of a main valve slide which is displaceably arranged in the casing. When the main valve slide is in the intermediate position, the inlet is blocked. The actuating means assigned to the main valve slide here has, in the region of the opposite ends of the main valve slide, a pressure chamber which is received therein, and a piston which is supported in each case by the valve casing in the pressure chamber And the pressure chamber can be impacted by a pressure medium waiting at the inlet of the main control valve casing through a flow path disposed in the main valve slide. In this case, the pressure medium supply assigned to the at least one pressure chamber can be controlled by a servo valve slide, which is displaceably arranged in the main valve slide, and the servo valve slide is mechanically connected to it. The moving means itself can be operated by an assigned pilot control valve in response to a motor signal that can be supplied thereto. The servo valve slide planned here, which is assigned an actuating means, requires a relatively large production cost and required area. Furthermore, the overall slowness comprised here of the slowness of the servo valve slide and the main valve slide is relatively large.

  Similarly, German patent application 103 25 067.0, which has not yet been published, proposes a similar arrangement in which the servo valve slide incorporated in the main valve slide is actuated hydraulically. However, this does not avoid the above disadvantages.

From US Pat. No. 5,237,968, three hydraulic collective machines are in the form of injection valves and inflow and discharge valve actuators, with a corresponding timing shift by a slide valve with a common slidable control slide. Controlled, four-cycle engines are known. Because this type of configuration requires a relatively large flow cross section, the control slide has a relatively large diameter. In this known configuration, the control slide cooperates with a compression spring at one end. The other end of the control slide closes a pressure chamber that can be impacted by a medium waiting at the pressure medium inlet of the slide valve, whereby the impact application can be controlled by a pilot control valve having a piezoelectric element. The pressure chamber bordering the control slide here has a relatively large cross section corresponding to the front face of the control slide. For this reason, a relatively large fluid volume is required to cause a change in the position of the control slide. For this reason, experience requires a relatively large amount of time, which leads to the undesirable dynamic characteristics of the known control valves. If higher pressures are applied, the position of the control valve can be incorrect. Thus, it has been found that the known arrangement is very slow and not accurate enough.
German Patent Application No. 103 11 493.9 German Patent Application No. 103 25 067.0 U.S. Pat.No. 5,237,968

  Thus, from this, the object of the present invention is to create a device of the type described at the beginning which is realized without servo means and at the same time guarantees excellent dynamic characteristics and high accuracy.

  This problem is solved by the combination of features that form the basis of claim 1.

  In this way, the hydraulically actuated injection means and hydraulically actuated cylinders of a two-cycle large diesel engine, in particular, are used to control the timed connection between two pressure medium impact collective machines and one pressure medium source. A device has been proposed for embodying the time shift of the evacuated discharge valve, which comprises a main control valve formed as a slide valve that creates a connection between the pressure medium source and the collecting machine to be impacted. The main control valve casing, which receives the displaceable main control slide, comprises an inlet connected to the pressure medium source and two outlets assigned to the collecting machine to be impacted, these outlets being It can be connected to the inlet via a main control slide, which can be displaced by the assigned actuating means, or alternatively can be separated from the inlet and unloaded, The actuating means assigned to the id includes the counteracting adjusting means assigned to the two opposite ends of the main control slide, wherein at least one of the adjusting means is a pressure chamber arranged in the casing. Can be impacted or unloaded by a medium waiting at the inlet through a flow path placed in the casing, which is attached to the casing and communicates via a pilot control valve operable in response to at least one assigned control signal With a possible pressure chamber and a moving piston defining the pressure chamber and acting on the main control slide, the effective piston area of the moving piston being smaller than the adjacent front face of the main control slide.

  Since the pressure chambers of the adjusting means facing each other are on the casing side, the supply or unloading of the pressure medium can be controlled, preferably directly by a pilot control valve. Advantageously, the servo control slide located in the main control slide is thereby unnecessary. Accordingly, the effective piston area of the moving pistons of both adjustment means can be made relatively small, so that a relatively small amount of hydraulic fluid is advantageously required to cause a change in position of the main control slide. Therefore, the reaction time present is advantageously very short. Thus, the main control slide according to the invention not only allows the implementation of the switching function, but also achieves the desired course of the switching event, for example the desired injection model.

  Advantageous embodiments of the superordinate measures and developments suitable for the purpose are given in the dependent claims.

  The main control slide can preferably be assigned sensor means for detecting its axial position, so that its output signal can influence the pilot control valve. This advantageously allows the creation of a closed control system and thereby a high accuracy with respect to the achievable position of the main control slide, and even when a relatively high hydraulic fluid pressure is provided, This results in particularly good dynamic properties. With the help of the feedback proposed here, the movement forces exerted on the main control slide by the adjusting means facing each other are made relatively uniform at each position in the movement path of the main control slide. This thus advantageously achieves each desired injection model.

  The sensor means can conveniently be embodied as measuring means for scanning the position of the main control slide in a non-contact manner. This advantageously eliminates error sources that take the form of frictional forces or the like that act against the movement of the main control slide.

  A further advantageous measure is that the adjusting means facing the adjusting means sensitive to the pilot control valve comprises a pressure chamber that can be impacted by a constant pressure, which is likewise arranged in the casing and is the main control. It is defined by a moving piston acting on the slide. This simplifies the configuration of the arrangement according to the invention. The moving piston, which defines a pressure chamber that can be impacted by a constant pressure, can thereby cooperate with the main control slide by means of an additional pressure spring or preferably directly. This shortens the reaction time and avoids resonance.

  Further advantageous embodiments of the above measures and suitable developments are described in the remaining dependent claims and can be taken from the description of the examples below using the drawings.

  The main field of application of the invention is two-cycle diesel engines, in particular two-cycle large diesel engines such as are used, for example, as marine drive engines. In this case, an engine that operates relatively slowly with large piston stroke and corresponding large injection amount and long injection time and long discharge valve opening time becomes a problem. A large amount of power is required to operate the injection means and the discharge valve.

  This type of two-cycle large diesel engine typically includes a plurality of cylinders arranged one after the other in a row. FIG. 1 schematically shows only one cylinder of this type. A piston 2 is movably disposed in the cylinder 1. The piston 2 is connected to a crosshead 4 through a piston rod 3, and the crosshead 4 cooperates with a crankshaft 6 through a connecting rod 5. The piston 2 defines a combustion chamber 7 into which fuel can be impact injected through injection nozzles 8 arranged in the region of the cylinder cover, at least one, in the illustrated embodiment two. In the area of the cylinder liner, an air intake slit 9 connected to the air supply means is provided, which is controlled by the piston 2 passing through these slits, and through the air intake slit 9 the combustion chamber 7 with air Can be given an impact.

  Exhaust gas generated during combustion passes through a central discharge port 10 prepared in the area of the cylinder cover and enters a discharge conduit 11 separated therefrom. A discharge valve 12 is assigned to the discharge port 10, and the discharge valve 12 can be moved up and down by an actuator 13 that is assigned and formed as a hydraulic collective machine, whereby the discharge port 10 is opened and closed. An injection pump 14 is assigned to the injection valve 8 in this embodiment, and its pump chamber 15 can be impacted by fuel prepared through the supply means, as indicated by the supply arrow 16. Fuel is discharged from the pump chamber 15 by an actuator 17 including a so-called plunger, which is likewise formed as a hydraulic collective machine, whose piston is connected to the plunger.

  The actuator 13 of the discharge valve 12 and the actuator 17 of the injection pump 14 are operable through impact application by a hydraulic pressure medium, which is supplied through a pressure medium source 18, here. This action takes place depending on the angular position of the crankshaft 6 and possibly further engine signals such as speed, load, pressure. In the illustrated embodiment, the pressure medium source 18 is formed as a pressure chamber that is impacted by hydraulic fluid through a pump 19 that can be driven directly or indirectly by the crankshaft 6 and that is maintained at the desired pressure. ing. In the illustrated embodiment, the pressure chamber forming the pressure medium source 18 is formed as a common rail, from which there are a plurality of conduits 20 leading to the assigned consumption object, each of which is assigned to an assigned valve. Can be controlled up and down. In a configuration with multiple cylinders, a common rail can be planned that passes through all or at least a group of cylinders.

  In order to control the application of pressure impact between the hydraulic collective machine forming the actuator 13 of the discharge valve 12 and the hydraulic collective machine forming the actuator 17 of the injection pump 14, these actuators are connected to one common main control valve 21. Assigned to. This main control valve is formed as a slide valve, this casing 25 comprising a lumen assigned to the main valve slide 26, here an inlet 22 assigned to the pressure source in the form of a common rail 18, and actuators 13, 17 And two additional outlets 40 are provided here, but at least one further inlet 40, which returns to the pressure medium tank not shown in more detail. Can be connected to the return pipe. The inlet and outlet are in communication with a notch prepared in the area of the lumen assigned to the main valve slide 26, which can be controlled up and down by the control edge of the main valve slide 26. The main valve slide 26 has a relatively large diameter to achieve a large flow cross section that allows for high flow rates.

  The main valve slide 26 has a central zero position and is movable from side to side in the axial direction starting therefrom. In the central zero position of the main valve slide 26 according to the figure, the inlet 22 is isolated from the outlets 23, 24, which are connected to one assigned outlet 40 each time. For this purpose, the main valve slide 26 is provided with a stud 41 which turns around the inlet 22 or an annular notch communicating therewith as best seen in FIG. When the main valve slide 26 deviates from the center position shown to the right or left, the inlet 22 or the annular notch communicating with it is connected to the outlet 23 or 24 or the annular notch communicating with it each time. The At the same time, there is no connection to the outlet 40 at normal pressure. The main valve slide 26 further comprises an annular notch 42 aligned with the side of the stud 21, which is larger than the lateral protrusion of the stud 41 above the annular notch on the inlet side. In the case of axial sliding of the main valve slide 26, the axial direction is wide enough to make the desired connection between the inlet 22 and the outlet 23 or 24. In this case, the open flow cross section depends on the position of the main valve slide 26. At the right end position or the left end position, the flow cross section reaches its maximum expanded state. In order to avoid shocking vertical control of the flow path, the stud 41 can be provided with an appropriate clearance.

  The main valve slide 26 is axially movable by assigned operating means. This includes adjusting means 60, 61 assigned to each end of the main control slide 26 facing each other in the axial direction, as best seen in FIG. Each of these adjusting means has a pressure chamber 62 which can be impacted by a pressure medium at the inlet 22 formed by a bag-like lumen on the casing side which exits the lumen of the valve casing 25 which receives the main valve slide 26. This pressure chamber 62 is then defined by a moving piston 63 or 64 assigned towards the main valve slide 26, which faces directly or indirectly on the adjacent front face of the main valve slide 26.

  One of the pressure chambers 62 is the lower pressure chamber 62 in the illustrated embodiment, but an impact is applied at a constant pressure. For this purpose, this pressure chamber 62 is connected to the inlet 22 through a planned lumen system 65 in the valve casing 25. A return connection is not required here. The moving piston 64 can be supported on the main valve slide 26 through a pressure spring which is preferably in the form of a leaf spring. However, the moving piston 64 can act directly on the main valve slide 26 like the facing moving piston 63 for the purpose. Advantageously, the moving pistons 63, 64 can be firmly connected to the main valve slide 26. This ensures that there is always a body contact on the opposing contact surfaces of the associated component.

  The opposing pressure chamber 62, here the pressure chamber 62 above in FIG. 2, can be impacted by a controllable pressure. For this reason, a pilot control valve 43 is preferably provided which is attached to the valve casing 25 and can be impacted by a control signal, and this pilot control valve 43 is formed through a lumen system on the valve casing side, i.e. Through a flow path 67 placed in the valve casing 25, it is connected to the assigned pressure chamber 62 and the inlet 22 and the assigned normal pressure outlet 40.

  The effective piston area of the moving piston 63 is essentially smaller than the assigned front face of the main valve slide 26, just as the effective piston area of the moving piston 64 is. On the other hand, the effective piston area of the moving piston 63 that can be given an impact by a controllable pressure is preferably twice as large as the effective area of the moving piston 64 that can be given an impact by a constant pressure on the opposite side. Thus, when the larger moving piston 63 is impacted by the pressure at the inlet 22, the force generated here overcomes the force generated by the smaller moving piston 64 that is impacted by the same pressure, so the main valve Slide 26 moves downward against a smaller force in the illustrated embodiment. When the upper pressure chamber 62 is unloaded and thereby the larger moving piston 63 is unloaded, the main valve slide 26 is illustrated by the opposed moving piston 64 that is impacted by a constant force. In the embodiment, it moves upward.

  If a 2: 1 area ratio is planned, the same effective movement force will result in both directions. Since the effective area of both moving pistons 63, 64 is relatively small compared to the assigned front face of the main valve slide 26, it is advantageous that less pressure medium is required to carry out the desired moving action, i.e. A quick reaction and a short reaction time result.

  The main valve slide 26 which receives the forces in the opposite directions of the adjusting means 60, 61 moves when the moving force acting on the adjusting valve 60 is unbalanced, and stops at the corresponding position when balanced. Thus, the main valve slide 26 can be held at each desired position by a corresponding balance of the moving forces acting on it. In this way, it is possible to carry out each desired operation process of the subordinate actuators 13 and 17. Thus, for example, it is possible to inject a small amount first at the start of an injection event, increase this amount in the course of the injection event, and end this event abruptly. Similarly, it is also possible to decelerate the lift piston assigned to the discharge valve 12 by applying a brake at the end of the opening operation so that final position damping is not required.

  It is suitable for the purpose that the pilot control valve 43 is formed as a proportional valve, which feeds the assigned flow path from the inlet 22 to the pressure chamber 62 or from the pressure chamber 62 to the outlet 40. It opens and closes in proportion to the signal that is received. The pilot control valve 43 is assigned signal generating means 29, which receives the control signal and converts it into a signal suitable for the operation of the pilot control valve 43. The signal supplied to the signal generating means 29 can be generated by a signal transmitter in accordance with the supplied motor signal. In the illustrated embodiment, the signal transmitter is planned as a computer 68, which depends on the motor signal indicated by the inlet arrow 69 supplied, based on the program contained therein. Signals that can be processed by the signal generating means 29 are calculated, which correspond to the desired instantaneous position of the main valve slide 26 in each case. The outlet of the computer 68 is connected to the inlet of the signal generating means 29 by a signal line 70.

  In order to improve accuracy, in the illustrated embodiment, feedback by the actual position of the main valve slide 26 is planned. For this reason, sensor means 71 for detecting the axial position of the main valve slide 26 is assigned. The output of the sensor means 71 accordingly forms an actual value, which is compared with the theoretical value calculated by the computer 68 based on the program stored in the computer and the supplied motor signal. . The output of the sensor means 71 corresponds to the actual value input of the computer 68. The signal formed from the difference between the actual value and the theoretical value calculated by the computer 68 is supplied to the signal generating means 29, from which the signal generating means 29 forms an adjustment signal for the pilot control valve 63. Thus, practically, as a result, a closed control system is obtained, and thereby high accuracy is obtained. This allows the application of high pressures, which can particularly reduce the effective area of the moving pistons 63,64.

  In order to avoid the movement resistance exerted on the main valve slide 26 by the sensor means 71, the sensor means 71 is provided with measuring means that work in a non-contact manner. This is formed as an inductive measuring means in the illustrated embodiment, which fits into the axial lumen 72 of the main valve slide 26 with radial play and functions as an anchor. 73 and a coil 74 disposed in the main valve slide 26 and surrounding the lumen 72. Suitably, the lumen 72 is open at the end facing the rod 73.

  In the illustrated embodiment, the lumen 72 is disposed coaxially with the axis of the main valve slide 26. Correspondingly, the adjusting means 61 on the sensor means side is arranged eccentric with respect to the axis of the main valve slide 26. On the other hand, the adjusting means 60 facing this is arranged coaxially with the axis of the main valve slide 26 and correspondingly also with the axis of the lumen 72. Therefore, this is formed as a bag-like lumen from which the branched pipe 75 is inclined so as to avoid wear by the moving piston 63. This can be securely connected to the main valve slide 26 in an advantageous manner. The moving piston 64 on the opposite side can likewise be fixed to the main valve slide 26 so as to ensure a constant contact. However, it can be considered that the moving piston 64 is supported by a spring. The moving pistons 63, 63 can be a unitary structure, but preferably they can be an assembled structure as in the illustrated embodiment.

  In the embodiment based on FIG. 1, the injection pump 14 is located above the injection valve 8, and the actuator 17 of the injection pump 14 can be controlled along with the actuator 13 of the discharge valve 12 by the control device according to the present invention. However, the control device according to the invention can find application even in an arrangement without an injection pump. This type of embodiment is based on FIG.

  In this case, a common rail 18 'that can be given an impact by a pre-pressurized fuel is planned, and a flow path 20' that leads to the cylinder 1 comes out from here, and these flow paths are selected by the control device according to the present invention each time. Thus, it can be connected to the actuator 13 of the injection valve 8 or the discharge valve 12. The structure of the main control valve 21 of the control device according to the invention and the pilot control valve 43 assigned to it corresponds in this case to the embodiment already described above, so that this is referred to in order to avoid repetition. Can be put out. The difference from the above-described example is that in the case of the embodiment according to FIG. 3, a pre-pressurized fuel is used as the pressure medium. Thus, the common rail 18 'serving as a pressure medium source is impacted by the fuel through the assigned pump 19'. The hydraulic collecting machine forming the actuator 13 of the discharge valve 12 is operated by fuel as a pressure medium.

1 is a schematic view of a two-cycle large diesel engine having a control device according to the present invention for controlling an actuator of an injection pump and a discharge valve. FIG. 2 is an enlarged view of a control device based on FIG. FIG. 2 is a view showing a modification of FIG. 1 having a common rail impact-type injection means without a pump.

Explanation of symbols

1 cylinder
2 piston
3 Piston rod
4 Crosshead
5 Connecting rod
6 Crankshaft
7 Combustion chamber
8 Injection nozzle
9 Air intake slit
10 Central outlet
11 Discharge conduit
12 Discharge valve
13 Actuator
14 Injection pump
15 Pump room
16 Supply arrow
17 Actuator
18 Pressure medium source
18 'common rail
19,19 'pump
20 pipelines
20 'flow path
21 Main control valve
22 entrance
23,24 Exit
25 Casing
26 Main valve slide
29 Signal generation means
40 Exit
41 stud
42 Annular cutout
43 Pilot control valve
60,61 Adjustment means
62 Pressure chamber
63,64 moving piston
65 Lumen system
68 Calculator
69 Entrance arrow
70 Signal line
71 Sensor means
72 lumens
73 Fixing bar
74 coils

Claims (12)

A device for controlling the connection between two pressure medium impact type collective machines and one pressure medium source, in particular a hydraulically operated injection means (8) of a cylinder (1) of a two-cycle large diesel engine; A device for operating the hydraulically operated discharge valve (12) at different timings,
A main control valve casing (21) that receives a displaceable main valve slide (26) with a main control valve (21) formed as a slide valve that creates a connection between the pressure medium source and the collective machine to be impacted. 25) comprises an inlet (22) connected to a pressure medium source and two outlets (23, 24) assigned to the collecting machine to be impacted, these outlets being assigned operating means Can be separated from the inlet (22) via the displaceable main valve slide (26) and can be unloaded or alternatively connected to the inlet (22) and is assigned to the main valve slide (26). The stage comprises counteracting adjustment means (60, 61) assigned to each opposite end of the main valve slide (26), at least one of the adjustment means acting on the main valve slide (26) With moving piston (63), moving piston (63) defines a pressure chamber (62) disposed in the casing (25), the pressure chamber (62) having a pilot control valve (43) operable in response to at least one supplied control signal. Through the flow path (67) placed in the casing (25) that passes through, the impact can be applied or released by the medium waiting at the inlet (22), and the effective piston area of the moving piston (63) is the main control Device smaller than the front face of the slide (26).   Device according to claim 1, characterized in that the main control slide is assigned sensor means (71) for detecting its axial position and its output signal can influence the pilot control valve (43).   The output signal of the sensor means (71) is compared with a predetermined theoretical value, and if there is a difference between the theoretical value and the actual value, the pilot control valve (43) is operable. 2. The device according to 2.   4. Device according to claim 2 or 3, characterized in that the sensor means (71) preferably comprises inductive measuring means for scanning the position of the main valve slide (26) in a non-contact manner.   The adjusting means (61) placed opposite to the adjusting means (60) that can be influenced by the pilot control valve (43) includes a pressure chamber (62) capable of applying an impact at a constant pressure, and the pressure chamber ( 62) is defined by a moving piston (64) which is likewise arranged in the casing (25) and acts on the main valve slide (26). The device described.   The pressure chamber (62) capable of being impacted by a constant pressure is connected to the inlet (22) through a flow path (65) placed in the casing (25). apparatus.   7. The device according to claim 1, wherein the moving piston (63, 64) is fixed to the main valve slide (26).   The moving piston (63) of the adjusting means (61), which can be influenced by the pilot control valve (43), can be impacted by a constant pressure placed opposite to the moving piston (64) of the adjusting means (61) 8. The device according to claim 1, wherein the device has a larger effective piston area.   9. The pilot control valve according to claim 1, wherein the pilot control valve is formed as a proportional valve, and the proportional valve opens and closes an assigned flow path in proportion to a supplied control signal. The device according to item.   The movement force exerted on the main valve slide (26) by the adjusting means (60, 61) placed facing each other is the position of the main valve slide (26) between its end positions by the pilot control valve (43). 10. The device according to any one of claims 1 to 9, characterized in that the device can be adjusted.   Main control valve in a two-cycle diesel engine, in particular a two-cycle large diesel engine, having at least one main control valve (21) assigned to the actuator (13, 17) of the discharge valve (12) and the injection pump (14) The pressure medium source (18) connected to the inlet (22) of (21) is formed as a common rail that can be given an impact by hydraulic oil, according to any one of claims 1 to 10. The device described.   In a two-cycle diesel engine, especially a two-cycle large diesel engine, the pressure medium source (18 ') connected to the inlet (22) of the main control valve (21) must be formed as a common rail that can be impacted by fuel. The main control valve (21) is capable of controlling the operation of the injection valve configuration and the actuator (13) assigned to the discharge valve (12) shifted in timing. 11. The apparatus according to any one of claims 1 to 10.

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