KR100491035B1 - A multi cylinder, two-stroke crosshead internal combustion engine - Google Patents

Abstract

In each cylinder, a multi-cylinder two-stroke crosshead internal combustion engine has a hydraulic central unit 11 with a support console 13 and a block-type via 14. The body comprises ports, control valves 29 and 30 electrically controlled for the operation of the actuator of the exhaust valve, a driver hydraulically driven by the fuel pump, internal channels 25, 25 ', 25 ", 25 " ', 27, 27', 27 ", 27 " 'and 34, the control valve connects ports to the high pressure pipe 15 or the drain pipes 22, 23.

Description

A multi cylinder, two-stroke crosshead internal combustion engine

The present invention relates to a multi-cylinder two-stroke crosshead internal combustion engine engine having a plurality of exhaust valves and fuel pumps, wherein at least one exhaust valve in the hydraulic central unit is operated by hydraulic fluid pressurized by hydraulic drive means. .

Conventionally, there have been proposals for carrying out hydraulic operation of exhaust valves and fuel pumps of large two-stroke crosshead engines instead of the well-known camshaft operation. Applicant's 1929 Danish Patent No. 41046 has proposed a hydraulically driven fuel pump, and recently patented a hydraulically driven fuel pump as Danish Patent No. 151145, and Danish Patent No. 148 664 electrically. Patents have been issued for controlled and hydraulically actuated exhaust valves.

Several known proposals for the full hydraulic operation of fuel pumps and exhaust valves of large two-stroke crosshead engines have not been applied commercially to the engines because of the complex structure of the hydraulic supply and control system. This is because the risk of failure of components to such an extent is high. In addition, it is well known that the increased risk of failure associated with conventional mechanical systems is that the hydraulic system is very sensitive to incorrect mounting and that defects resulting from such inaccuracies may appear to be defects with no apparent factor after long term operation.

It is an object of the present invention to simplify the installation of a hydraulic system.

Hydraulic central unit according to the present invention for this purpose, the engine is provided with a hydraulic central unit for the cylinder inside the engine, the hydraulic central units, at least one connecting the at least one pressure pipe for the actuator of the exhaust valve A block body comprising a port, at least one port for connecting a hydraulic drive of the hydraulically driven fuel pump, and a control valve electrically controlled to control the exhaust valve; A hydraulically driven fuel pump; An inner channel, wherein the control valve connects the port to a high pressure pipe for supplying pressurized hydraulic fluid or to a low pressure pipe for shutting off the hydraulic pressure, and the fuel in the cylinder is a piston type hydraulically driven fuel pump. It is characterized by discharged by (10).

In terms of reliability, all the central elements for the hydraulic system of the cylinder are collected in a central unit with the most sensitive elements to the block-type body, allowing hydraulic fluid to flow through the various valves and the various valves and hydraulic locations. The connection branch between the and the high pressure tube has several advantages by allowing it to be formed as channels with holes intersecting with each other where necessary. The hydraulic central unit can be manufactured in a special place, taking into account the stringent requirements on the cleanliness of the hydraulic system, and then the central unit is transported in several main parts separated into the workshop where it is mounted on the cylinder of the engine or It can be transported in assembled form. When mounted to the engine cylinder, many small tubes must not be assembled so that control valves are inserted or connect the control valves to the supply line and hydraulic fluid consumers.

Parts of the individual cylinders can be assembled into a standardized central unit in several identical central units of the engine, for example to have spare parts for complete or partial replacement of any defective hydraulic central unit of the engine in a ship. This makes it easy to prepare for failure of the central unit.

The modularization of the components of the hydraulic system into central units gives great flexibility in the design of the engine, which is a great advantage for large two-stroke crosshead engines. The large two-stroke crosshead engines are typically assembled when ordered individually with the number of cylinders and cylinder outputs for a particular order, since the number of central units can be easily adapted to the selected number of cylinders in each case. to be.

In a preferred embodiment, the central unit has a console mounted on the top plate in the cylinder cross section from which the cylinder liner protrudes upwards and the block body is mounted on the top of the console. The console preferably has a height such that the top surface of the block-shaped body is at least 80 cm above the top plate. The central unit is divided into a block body and a support console, which simplifies the manufacture of the central unit, which allows the central units in different proportions to the same cylinder size with different cylinder sizes. This is because the consoles can be manufactured in various sizes. Mounting the console to the top plate of the cylinder part is extremely simple, the console supporting the cylinder liner. The height of the console, which is placed on the upper surface of the block-shaped body at least 80 cm above the top plate, allows the valve-shaped body with ports for the exhaust valve connection with several valves to be above the passageway. The working position is installed on the top plate so that it is at an optimal height when the person is standing. Furthermore, the console is arranged on the upper surface of the block body close to the cylinder cover, so that the hydraulic connection between the central unit and the actuator of the exhaust valve is shortened so that the actuator consumes energy for pressurizing the hydraulic fluid at the high pressure connection. Will be low.

It is desirable to provide one central unit per cylinder, which is the simplest and most reliable in design, while the separation of the central unit affects only one cylinder in relation to that central unit.

It is possible to connect a high pressure tube directly to the block body where the supply of high pressure hydraulic fluid will be used in the valves, but each central unit contains a portion of the high pressure tube. The integration of the high pressure tube part into the central unit allows the hydraulic system to be extended to higher number cylinders by standard pipe parts having a length that matches the distance between two neighboring central units together with the number of central units. To be.

It is preferable that the control valve on the block body controls fuel supply from the piston pump independently of the control valve for the actuator of the exhaust valve. The hydraulically driven main components of the cylinder are concentrated in the block body at a short distance from the cylinder cover, and the injectors and exhaust valves are preferably mounted such that the length of the hydraulic tubes is short.

In a variant to this embodiment, the fuel pump with associated hydraulic drive means is mounted on the top of the block body of the central unit. As a result of using the block-shaped body as the base of the fuel pump, the hydraulic pump driving means is located directly in the port of the block-type body, and the separate bases for the fuel pump are omitted, which makes the structural design very simple. The reduced number of components reduces the risk of failure and the fuel pump can be mounted in the central unit before being transported to the engine installation site.

In a preferred embodiment, the control valve of the central unit is electronically controlled by a cylinder control unit or engine control unit. Electronic control provides a very beneficial effect of freely controlling the exhaust valves and fuel pumps during the engine cycle, ie to continuously adjust the valve opening and closing timing while the engine is running.

In order to prevent air penetration into the hydraulic system, the hydraulic central unit can be connected to a low pressure tube for supplying hydraulic fluid at low pressure, preferably at pressures less than 4 bar. This supply low pressure tube is, for example, through the throttle to the drive valve of the fuel pump and the control valves of the actuator of the exhaust valve so that pressure is maintained to prevent the ingress of air into the hydraulic systems when the pressure is released. May be connected to the drain or low voltage ports of the. Instead of using a low pressure pipe in addition to the drain pipe, a hydraulic fluid is required at a moderately low pressure by branching from the high pressure pipe and passing through a throttle means for reducing the pressure of the fluid, for example to a suitable pressure level of 0.5 bar to 3 bar. If the hydraulic fluid can be supplied, the hydraulic fluid can be discharged to the drain pipe.

The hydraulic central units are completely independent of each other, all supplied with hydraulic fluid from the high pressure line. The consumption of hydraulic fluid in one central unit does not affect the other central units, so the central unit preferably comprises at least one high pressure fluid accumulator. Fluid accumulators supply hydraulic fluid to the central unit itself at the time of hydraulic consumption, preventing significant pressure fluctuations in the high pressure line.

Hydraulic systems can be formed on the supply side of the central units to include parts of the high pressure pipe connected to each other by two concentric high pressure pipes mounted therebetween, the two concentric high pressure pipes being connected to the inner pipe. An outer pipe, the inner pipe being inserted at both ends in a pressure-tight manner into a bushing clamping the side of the central unit, the outer pipe being movable in the outer pipe in its longitudinal direction and larger than the outer diameter of the bushing of the inner pipe. It has a cup-shaped bore having a diameter and is provided at one end with a cup-type bushing which can be mounted on the side of the central unit. The concentric high pressure pipes are able to withstand the maximum hydraulic pressure and provide great reliability for failure. In normal operation, the hydraulic fluid flows only through the inner pipe and the annular space between the two pipes may comprise a leak monitor means for emitting an alarm signal indicating the breakage of the inner pipe if a leak is detected therein. . The operation of the engine can continue until repair is made, and the pressure is maintained by the outer pipe.

The embodiment provides the advantage that the central units with double pipes are easy to mount on the cylinders of the engine even when there are distance changes in the width of the engine cylinders. Even after mounting the central units in the engine cylinder with a rather large tolerance, the distance differences can be corrected as follows. Before the pipes are arranged between the two central units, the two bushings of the outer pipe are pushed towards each other so that the bushings of the inner pipe are exposed. The flanges of the inner pipe are then mounted to their respective central units. The flanges of at least one of these inner pipes can be movable and can be rotated to some extent in the inner pipe to correct for length changes and incorrect mounting between the central units. The cup bushings can then be pushed over the bushings of the inner pipe and secured to the respective central units.

Hereinafter, with reference to the accompanying drawings by way of example a preferred embodiment of the present invention will be described in detail the present invention.

The hydraulic system supplies the hydraulic fluid under pressure to the hydraulic drive means of the cylinders 1 in a multi-stroke two-stroke crosshead engine 2. The hydraulic fluid may be delivered from the storage tank and may be, for example, standard hydraulic oil, but it is preferred to use engine lubricating oil as the hydraulic fluid, which is supplied from the oil tank 3 of the engine. The main pump 4 supplies hydraulic fluid to the low pressure tube 6 through at least one filter 5. The main pump maintains the low pressure tube at a pressure, for example in the range of 1 to 5 bar, preferably 2 bar. The pump station 7 may include a plurality of high pressure pumps to discharge hydraulic fluid to the high pressure pipe 8 in the range of 125 to 325 bar. The discharge pressure is adjustable according to the engine load. Some of the high pressure pumps may be driven by the output shaft of the internal combustion engine, and one or more of the high pressure pumps may be driven by an electric motor.

The crosshead engine can be for example a propulsion engine of a ship or a fixed drive of a power plant. The engine does not have a conventional camshaft, the exhaust valve 9 and the fuel pump 10 are hydraulically driven and electrically controlled.

The high pressure pipe 8 from the pump station is mounted on the hydraulic central unit 11 on the side with respect to its part 12, pre-mounted and integrated in the lower part of the central unit in the console 13 and block-shaped on its upper surface. Support body 14. The pressure tube 15 extends from the body 14 to the actuator 16 of the exhaust valve, and the drain tube 17 from the actuator leads back to the body 14. The body 14 may be connected to the hydraulic driving means for the fuel pump 10 by any one of the high pressure pipe or the return pipe. The fuel pump discharges fuel to the plurality of injectors through the pressure pipes 18.

Each cylinder of the engine is connected to an electronic control unit 19 which receives the overall synchronization signal and the control signals via the wires 20 and outputs the control signal to the control valves of the body 14 via the wire 21. have.

The low pressure pipe 22 branches from the upstream side of the low pressure pipe of the pump station 7 to supply the pressure fluid to the central unit 11 at a low pressure of less than 4 bars, typically about 2 bars.

The drain pipe 23 is connected to the central unit, for example, in a frame box of the engine and which discharges hydraulic fluid used as a common drain port in communication with the oil tank 3.

2 shows an example of the main connections of the central unit 11. The common feed pipe 25 branches from the portion 12 of the high pressure pipe and leads to the branch pipe to the consumer of the block body 14, which is schematically dotted. In normal operation the main shutoff valve 24 is in the open position shown, where the high pressure tube is connected to the body 14. When part of the hydraulic system of the cylinder has to be disassembled for inspection, maintenance or replacement, the valve 24 can be set to another position by manual or electronic manipulation, whereby the feed pipe 25 is connected to a high pressure pipe. It is isolated from the part of and connected to the drain pipe 23 through the branch pipe 23 'so that the pressure of the entire high pressure system of the central unit is relieved so that it can be disassembled with minimal waste of the hydraulic fluid.

The pre-mounted part 26 of the low pressure tube in the central unit is connected to the block body via a branch pipe 27. The throttle 28 of the branch pipe limits the supply pressure to the body 11 to 1.5 bar. In the block-shaped body, the branch pipe is connected to the supply ports of the control valve 29 for the pump drive through the channels 27 ', 27 ", 27"' and the main valve 31 for the control valve 30 and the valve actuator. Are connected to each of them. Moreover, the feed pipe is connected to the control valve 29 and the supply port of each of the control valve 30 and the main valve 31 through the channels 25 ', 25 ", 25"' of the body 11.

The control valve 30 is operated electronically as a three port two position valve. The control valve is actuated by the magnetization of one of the two coils located at either end of the valve slider, for example of magnetic locking material, in the form of magnetic locking in both positions. For safety in the event of a failure in the magnetization of the two coils a spring 32 is pre-mounted so that the valve slider takes the position shown in the figure, and the low pressure tube is connected to the actuation supply port. Instead, the control valve may be a conventional solenoid valve. The discharge port of the control valve 30 is connected to the intermediate channel 33, the channel 33 is a pressure acting on the piston surface of one end of the slider of the main valve 31 and the other end of the slider and the high pressure pipe It has a smaller area of piston surface that is in permanent communication. When the control valve 30 is in the position shown, high pressure acts on the small piston area to press the main slider to the position shown, where the low pressure tube is connected to the main valve outlet port via a channel 27 "'. The discharge port is connected through a channel 34 to a port for the pressure pipe 15 to the actuator of the exhaust valve, and when the control valve is operated to a second position where the intermediate channel is connected to the supply pipe 25, The acting high pressure urges the slider of the main valve to the second position, where the high pressure of the channel 25 "'is fed to the pressure tube 15 to cause the actuator to open the exhaust valve.

The control valve 29 is operated electronically as shown in the figure, and can communicate high pressure of the channel 25 'to its discharge port, and the channel 25' is also pump driven through the channel 35. It leads to a port through the pressure chamber of the means. In the intermediate position the supply ports of the control valve are disconnected from the discharge port and in other positions the discharge port of the control valve is connected to the channel 27 'of the low pressure tube, which restricts the pressure to, for example, 0.5 bar It has a throttle 36. The control valve may be a three-port three-position valve having a quick-action auxiliary slider for adjusting the main slider by hydraulic action. The auxiliary slider or the main slider is provided with a position sensor to output a signal to the valve set in the associated control device 19. The control valve may for example be of the type disclosed in the applicant's WO 94/29578.

Immediately after the main shutoff valve 24, a high pressure fluid accumulator 37 is connected to the supply pipe 25. The accumulator is assembled in a pressure vessel with an internal volume that is significantly larger than the amount of hydraulic fluid used in a single operation of the valve actuator 16. The interior volume is divided by a flexible membrane that separates the gas chamber from the fluid chamber in communication with the conduit 25. The gas chamber is pressurized to a pressure corresponding to the pressure of the high pressure tube 8 at the neutral position of the membrane. The central unit consists of two fluid accumulators 37 ', 37 "' of the same type, mounted on a block-shaped body 14 near the branch pipes 25 ', 25"' from the central feed pipe 25. ). When the control valve 29 or 31 is opened, most of the fluid is discharged from the accumulators 37 ', 37 "' of the body 14, and the supply pipe to the accumulators in the subsequent closing period of the control valve. Fluid is filled from 25. By placing the accumulator 37 in close proximity to the portion 12, a pressure drop in the high pressure tube 8 occurs as a result of fluid consumption by the cylinder.

Moreover, the block-shaped body includes drain channels 38 and 39, which drain hydraulic fluid drained from the pump drive unit and the valve actuator, respectively, to the drain pipe 23. Additional control valves such as valve 40 may be located adjacent to ports on the top of body 14.

The hydraulic central unit 11 is shown in more detail in FIG. 4. The console 13 comprises a front wall and at least two side walls which give great rigidity in the form of a box. The console is fixed to the top plate 41 of the engine frame box. The top plate supports the cylinder liner 42, the lower portion 43 of which is reduced in outer diameter and projects downward into the scavenging box 44 in the cylinder portion of the engine frame box. The exhaust valve 9 is mounted to the cover 45 clamped to the top plate with a cover stud 46, which is only partially shown in the figure. The passage 47 protrudes from the top plate 41. The height of the console allows the pressure tubes 15 and 18 to have a short length, resulting in a console height of 55-120 cm for large engines with cylinder bores of at least 500 mm. This provides a convenient working height for the operator standing in the aisle to disassemble into hydraulic elements mounted on the central unit.

The high pressure tube 8 is mounted to a steel body 48 extending from one wall of the console to the other wall. The steel body has a first channel consisting of a bore constituting the portion 12 and a second channel constituting the portion 26, and the main shutoff valve 24 is mounted on the front of the body of steel to repair. Allows easy access for The feed pipe 25 is formed to the block body as a pipe connected to the bottom of the body 14 and to a socket in which the accumulator 37 is mounted. Likewise, conduits 23 and 27 are formed as pipes under the body 14.

The block-shaped body 14 is formed with bores in the steel body with many internal channels for the high pressure passage and the low pressure passage and the drain passages. The control valves 29-31 are mounted on the front of the body. The fuel pump with drive is mounted directly on the top of the body 14 so that the pressure chamber of the drive is in direct communication with the port at the end of the channel 35.

The high pressure pipe 8 is formed as an inner pipe 49 and an outer pipe 50 concentrically arranged between the central units 11, the inner and outer pipes being able to withstand maximum high pressure. Two pipes are mounted between the central units and supplied as a prefabricated set of pipes that can correct for dimensional changes that are unavoidable in the mounting of the central units. On both ends of the inner pipe 49, bushings 51 and 51 'are inserted in a gas tight manner to clamp the sides of the central unit concerned. The inner pipe is movable longitudinally with respect to at least one of the bushings and can be rotated to an angle with respect to both bushings to compensate for inaccuracy in distance and alignment. The outer pipe has cup-shaped bushings 52, 52 'at each end, which are movable in the longitudinal direction of the outer pipe and can be mounted to the sides of the associated central units. These bushings can also be rotated at a small angle with respect to the outer pipe. The bushings 52, 52 ′ have cup-shaped bores having a diameter larger than the outer diameter of the bushings of the inner pipe to be movable over the bushings of the inner pipe.

The invention is not limited to only the specific embodiments described above. For example, other types of control valves having a plurality of steps or positions may be used, the low pressure pipe may be omitted or replaced by a drain pipe, and the body 14 may have more valves and channels than described above. And drain passages. It is also possible to provide hydraulically actuated cylinder elements from other forms of central unit, for example hydraulically driven cylinder lubricators. The cylinder lubricator may be mounted to the block body.

The hydraulic central unit according to the present invention can be assembled into the central units by modularizing the components of the hydraulic system has great flexibility in the design of the engine structure, which has a great advantage in the case of large two-stroke crosshead engine, In addition, the central unit includes a main shutoff valve for high pressure supply, which shuts off the central units individually, shuts down the single-cylinder central unit for overhaul and replaces defective parts. This allows the cylinder to be separated, resulting in a slight reduction in load, allowing the engine to continue operating. In addition, the central unit of the present invention can be divided into a block body and a support console to simplify the manufacture of the central unit, the central unit having a double-pipe pipe provides the advantage of easy mounting to the cylinders of the engine do.

Therefore, the hydraulic central unit of the present invention has the effect of having a high reliability against the engine stop and simplifying the installation and maintenance of the hydraulic system.

1 is a schematic configuration diagram of a hydraulic system for a two-stroke crosshead internal combustion engine engine according to the present invention;

2 is a schematic representation of a hydraulic system of a hydraulic central unit in the engine of FIG.

3 is a side view of the engine of FIG.

4 is an enlarged partial cross-sectional view showing a central unit.

5 is a side cross-sectional view of a dual-structure pipe between two central units.

Claims (14)

In a multi-cylinder two-cylinder crosshead internal combustion engine engine having a plurality of exhaust valves 9 and fuel pumps 10 operated by a device hydraulically driven by pressurized hydraulic fluid, The engine has hydraulic central units 11 for cylinders inside the engine 2, The hydraulic central units, At least one port for connecting at least one pressure tube 15 for the actuator of the exhaust valve, at least one port for connecting the hydraulic drive of the hydraulically driven fuel pump 10, and an electrical device for controlling the exhaust valve. A block-type body 14 including control valves 29 and 30 controlled by; A hydraulically driven fuel pump; Internal channels 25, 25 ', 25 ", 25"', 27, 27 ', 27 ", 27"', 34, The control valves 29 and 30 connect the port to the high pressure pipe 15 for supplying the pressurized hydraulic fluid or to the low pressure pipes 22 and 23 for blocking the hydraulic pressure. Multi-cylinder two-stroke crosshead internal combustion engine, characterized in that the fuel of the cylinder is discharged by a piston type hydraulically driven fuel pump (10). The method of claim 1, A multi-cylinder two-stroke characterized in that it has a console (13) mounted on the upper plate (41) of the cylinder portion, from which a cylinder liner protrudes upwards, and the block-shaped body (14) is mounted on top of the console. Crosshead Internal Combustion Engine. The method of claim 1, The console (13) is a multi-cylinder two-stroke crosshead internal combustion engine, characterized in that the height is such that the upper surface of the block-shaped body is at least 80cm from the top plate. The method of claim 1, Multi-cylinder two-stroke crosshead internal combustion engine, characterized in that one central unit (11) is provided per cylinder. The method of claim 1, Each central unit includes a portion of the high pressure tube (12). The method of claim 1, The block valve body control valve (29) is a multi-cylinder two-stroke crosshead internal combustion engine, characterized in that to control the fuel discharge from the piston pump independently of the control valve (30) for the actuator of the exhaust valve. The method according to any one of claims 1 to 6, The fuel pump (10) with the hydraulic device is a multi-cylinder two-stroke crosshead internal combustion engine, characterized in that the central unit is mounted on the upper surface of the block-type body (14). The method according to any one of claims 1 to 6, The control valve of the central unit is a multi-cylinder two-stroke crosshead internal combustion engine, characterized in that it is electronically controlled by a cylinder control unit (19) and the engine control unit. The method according to any one of claims 1 to 6, The hydraulic central unit is a multi-cylinder two-stroke crosshead internal combustion engine, characterized in that connected to the low pressure pipe 22 for supplying hydraulic fluid at a low pressure of less than 4 bar. The method according to any one of claims 1 to 6, The parts 12 of the high pressure tube 8 are connected to each other by two concentric high pressure pipes mounted between the central units, the two concentric high pressure pipes having an inner pipe 49. And an outer pipe (50), wherein the inner pipe is inserted at both ends in a pressure-tight manner into the bushings (51, 51 ') to clamp the side of the central unit, and the outer pipe has a cup-shaped bushing (52) at both ends thereof. 52 '), wherein the cup bushing is movable in the outer pipe in the longitudinal direction of the outer pipe and can be mounted on the side of the central unit and has a cup bore having a diameter larger than the outer diameter of the bushing of the inner pipe. Multi-cylinder two-stroke crosshead internal combustion engine. The method according to any one of claims 1 to 6, The central unit has at least one high pressure fluid accumulator (37) connected to the inner channel (25). The method of claim 11, And the accumulator has an internal volume greater than that of the hydraulic fluid in which the exhaust valve is used in a single operation. The method according to any one of claims 1 to 6, The drain pipe (23) is a multi-cylinder two-stroke crosshead internal combustion engine, characterized in that connected to the central unit for discharging the hydraulic fluid already used to the oil tank (3) of the engine. The method according to any one of claims 1 to 6, Control valve for exhaust valve control 30 is a multi-cylinder two-stroke crosshead internal combustion engine, characterized in that the solenoid valve.