KR102098753B1 - Fuel or lubrication pump for a large two-stroke compression-ignited internal combustion engine - Google Patents

Abstract

The present invention relates to a pump for supplying fuel or lubricant to a large two stroke compressed ignition internal combustion engine. The pump 40 includes two or more pump parts 41, 42 and 43. Each pump portion (41, 42, 43) includes a pump piston (62) slidably disposed in the pump cylinder (61) and a hydraulically driven drive piston (46) slidably disposed in the drive cylinder (45). , For driving the pump piston 62, a driving piston 46 is coupled to the pump piston 62.

Description

FUEL OR LUBRICATION PUMP FOR A LARGE TWO-STROKE COMPRESSION-IGNITED INTERNAL COMBUSTION ENGINE}

The present disclosure relates to a fuel or lubrication pump for a large low speed two stroke uniflow compressed ignition internal combustion engine.

Large two-stroke single-stream turbocharging compression ignition internal combustion crosshead engines (engines) are commonly used as propulsion systems for large ships or prime movers for power plants. Due to its enormous size, weight and power output, this engine is very different from the normal combustion engine, and the large two-stroke turbocharged compressed internal combustion engine itself is classified as a class.

Large two-stroke compressed ignition internal combustion engines have traditionally been operated with liquid fuels such as fuel oil and heavy oil. However, as interest in environmental aspects has increased, it is progressing toward using alternative fuels such as gas, methanol, coal slurry, and petroleum coke.

Some of these alternative fuel types have characteristics that are difficult to handle with conventional fuel pumps. Some are abrasive like coal slurries, some have poor lubrication properties like gasoline, others need cryogenics like liquefied gas.

WO 2016/015732 discloses a cylinder lubrication system with a plurality of cylinder oil pumps. Each cylinder oil pump is provided with a drive piston connected to a plurality of dosing plungers.

Therefore, there is a need to provide a pump capable of handling these alternative fuels.

In view of this background, it is an object of the present invention to provide a pump that overcomes or at least reduces the aforementioned problems.

The above and other objectives are achieved by the features of the independent claims. Additional forms of implementation are apparent from the dependent claims and detailed description and drawings.

According to a first aspect, there is provided a pump comprising two or more pump portions, each pump portion including a pump piston slidably disposed in a pump cylinder, and a hydraulically driven drive piston slidably disposed in a drive cylinder, wherein: The drive piston is coupled to the pump piston to drive the pump piston.

By providing a pump in which each pump piston is driven by a linear hydraulic actuator, any suitable pump piston can be driven in a completely flexible manner independent of the crankshaft limitations and inertia, so that the pump piston is fully adjusted to the liquid to be pumped. Enables the working profile of.

According to a first possible implementation of the first aspect, the pump further comprises at least one hydraulic control valve connected to the tank and the high pressure hydraulic oil supply source to control the flow of hydraulic oil to / from the drive cylinder of the one or more pump units. , The high pressure hydraulic oil supply source is preferably a variable and controllable pressure level.

According to a second possible implementation of the first aspect, the drive cylinder comprises a drive chamber and a return chamber.

According to a third possible implementation of the first aspect, the drive chamber is connected to a hydraulic control valve and the return chamber is preferably permanently connected to the hydraulic oil supply at a pressure lower than that of the high pressure hydraulic oil supply.

According to a fourth possible implementation of the first aspect, the drive cylinder is provided with a position sensor for sensing the position of the drive piston in the associated drive cylinder.

According to a fifth possible implementation of the first aspect, the fuel supply system further comprises an electronic control device for receiving a signal from a position sensor, and at least one of the hydraulic control valves is an electronic control valve coupled to the electronic control device. to be.

According to a sixth possible implementation of the first aspect, the electronic control device is configured to selectively connect the drive chamber of the pump section to a high pressure hydraulic oil source or tank.

According to a seventh possible embodiment of the first aspect, the electronic control device is configured to start the pump stroke of the other drive piston when the pump stroke of the drive piston approaches its end, such that it is small between the end pump stroke and the start pump stroke. There is overlap. Thus, a substantially stable flow can be achieved without large pressure fluctuations for the fuel or lubricant leaving the pump.

According to a possible eighth embodiment of the first aspect, the electronic control device is configured to take into account the dynamics of the end pump stroke and the dynamics of the start pump stroke to obtain a substantially constant flow for high pressure fuel or lubricant from the pump.

According to a ninth possible implementation of the first aspect, the electronic control device is configured to determine when the pump stroke of one of the drive cylinders / units should start and when the pump stroke of the drive cylinder should end. Therefore, it is possible to accurately control the point at which the pump stroke starts and particularly the point at which the pump stroke ends.

According to a possible tenth embodiment of the first aspect, the electronic control device is configured to operate each drive cylinder substantially continuously, preferably with little overlap.

According to a possible eleventh embodiment of the first aspect, the electronic control device is configured such that when one of the pump portions fails, the driving piston of the other pump portion is operated. Accordingly, redundancy is achieved, and even if one of the pump parts fails, the pump operation may continue.

According to a possible twelfth embodiment of the first aspect, the electronic control device is configured to operate the drive piston of another pump portion which functions to operate the drive cylinder of the other pump portion functioning substantially continuously, preferably in a small overlap.

 According to a thirteenth possible embodiment of the first aspect, the electronic control device is configured to adjust the position of the drive piston in which the drive chamber is separated from the high pressure hydraulic oil supply source in relation to the size of the liquefied gas flow from the high pressure pump to the high pressure vaporizer. Therefore, the position where the pump stroke is reversed can be maintained the same regardless of the speed and the resulting inertia of the pump piston and drive piston.

According to a possible fourteenth embodiment of the first aspect, the electronic control device is driven such that when the flow of fuel or lubricant from the pump increases, the drive chamber of the associated drive piston is separated from the supply of high pressure fluid in a direction opposite to the drive stroke direction. It is configured to adjust the position of the piston.

According to a fifteenth possible embodiment of the first aspect, the electronic control device comprises a drive piston in which the drive chamber of the associated drive piston is separated from the supply of high pressure fluid in the direction of the drive stroke direction when the flow of fuel or lubricant from the pump decreases It is configured to adjust the position of.

According to a possible sixteenth embodiment of the first aspect, the electronic control device is associated according to an algorithm or scheme, or optionally, to distribute a position where the pump piston is reversed in the stroke region of the pump piston to reduce wear of the pump cylinder. The drive chamber of the drive piston is configured to adjust the position of the drive piston separated from the high pressure hydraulic oil supply.

According to a seventeenth possible embodiment of the first aspect, the electronic control device is configured to control the pressure pumped fuel or lubricant delivered by the pump by controlling the pressure of the hydraulic oil supplied to the drive chamber. Thus, effective and instantaneous control over the pressure of the pumped fuel or lubricant is achieved.

According to a possible eighteenth embodiment of the first aspect, the electronic control device is configured to use a desired pressure for fuel or lubricant pumped with a feed-forward function to control the pressure of hydraulic oil supplied to the drive chamber. By using feed-forward control of the liquefied gas pressure through the hydraulic pressure, the pressure of the pumped fuel or lubricant can be controlled much faster and more reliably.

According to a possible nineteenth embodiment of the first aspect, the electronic control device is configured to use the measured pressure for fuel or lubricant pumped with a feed-back function to control the pressure of the hydraulic oil supplied to the drive chamber. Thus, nonlinearity and transients can be accommodated by the control system.

According to a possible twentieth embodiment of the first aspect, the electronic control device is configured to control the operation and stop of each drive piston independently of controlling the pressure of the hydraulic oil supplied to the drive chamber. Thus, the control strategy for the operation of the drive piston can be optimized by the electronic control device independent of pressure control.

In a possible twenty-first embodiment of the first aspect, the control device is configured to use a signal indicative of the position of the drive piston to control operation and stop of the drive piston.

According to a second aspect, a large two-stroke turbocharged compression ignition internal combustion engine according to the first aspect and any possible implementation thereof is provided.

According to a third aspect, a cargo ship is provided comprising the engine according to the second aspect.

According to a fourth aspect, a method is provided for pumping fuel or lubricant to an internal combustion engine to inject high pressure gas into an engine, the method comprising: storing the fuel or lubricant in a storage tank; And pumping fuel or lubricating oil to the engine with a pump, wherein the pump includes two or more pump parts, and each pump part is coupled with a pump piston to drive the pump piston and is slidable within the pump cylinder. It includes a pump piston and a hydraulic power-driven piston slidably disposed in the drive cylinder, the method comprising: supplying a high-pressure hydraulic oil to the drive cylinder to drive the drive piston; And controlling the pressure of the fuel or lubricant leaving the high pressure pump by controlling the pressure of the hydraulic oil supplied to the driving cylinder.

According to a first possible implementation of the fourth aspect, the method further comprises actuating one of the drive pistons during the drive stroke and then stopping the drive piston during the return stroke.

According to a second possible implementation of the fourth aspect, the pump piston and the drive piston are connected to each other and move in unison.

According to a third possible implementation of the fourth aspect, the method is configured to start the pump stroke of the other drive piston when the pump stroke of the drive piston approaches its end, so that there is a small overlap between the end pump stroke and the start pump stroke. Further comprising the step of being.

According to a fourth embodiment of the fourth aspect, the method further comprises taking into account the dynamics of the end pump stroke and the dynamics of the start pump stroke to obtain a substantially constant flow of fuel or lubricant from the pump to the engine. do.

According to a fifth possible implementation of the fourth aspect, the method further comprises making each drive cylinder operate substantially continuously, preferably with little overlap.

These and other aspects of the invention will become apparent from the examples described below.

According to the present invention, there is an effect of providing a fuel or a lubricating pump that overcomes or at least reduces the aforementioned problems.

1 is a front elevational view of a large two-stroke diesel engine according to an embodiment of the present invention.
FIG. 2 is a schematic representation of a fuel supply system for supplying high pressure natural gas from a LNG storage tank to a large two stroke diesel engine according to FIG. 1;
3 is an elevated state diagram of the high pressure pump of the fuel supply system of FIG. 2.
4 is a schematic representation of the high pressure pump of FIG. 3.
5 is a detailed cross-sectional view of the pump portion of the high pressure pump of FIG. 3.
6 to 8 are graphs showing the operation of the high pressure pump of FIG. 3.
9 is a schematic representation of a control system for controlling the high pressure pump of FIG. 3.
10 and 11 are graphs showing the piston motion of the high pressure pump of FIG. 3.

In the following detailed description, a fuel supply system for a large two-stroke low-speed turbocharging compression ignition internal combustion engine including a crosshead will be described with reference to exemplary embodiments, but the internal combustion engine is a two-stroke auto, four-stroke auto Or it may be another type of diesel, etc., and it should be understood that there may or may not be turbocharging and exhaust gas recirculation. In addition, a pump for supplying fuel or lubricant to a large two-stroke low-speed turbocharging compression ignition internal combustion engine including a crosshead will be described with reference to exemplary embodiments, but the internal combustion engine is a two-stroke Otto, four-stroke engine. It can be of other types, such as auto or diesel, and it should be understood that there may or may not be turbocharging and exhaust gas recirculation.

1 shows a large low-speed turbocharging two-stroke diesel engine with a turning wheel and a crosshead. In this exemplary embodiment, the engine is equipped with six cylinders in a row. Large low-speed turbocharging two-stroke diesel engines are usually supported by a cylinder frame supported by engine frame 6, and have 4 to 14 cylinders in a row. The engine can be used, for example, as a fixed engine that operates a ship's main engine or a power plant's generator. The total power of the engine can be, for example, in the range of 1,000 to 110,000 kW.

The engine is, in this example embodiment, a two-stroke single-stream compression ignition engine equipped with a scavenge port in the lower region of the cylinder liner 1 and an exhaust valve 4 in the upper center of the cylinder liner 1. The scavenger passes from the scavenging container 2 to the scavenging port of the individual cylinder 1. The piston in the cylinder (1) liner compresses scavenging, and high-pressure fuel such as gas fuel is injected through the fuel injection valve of the cylinder cover, so that combustion proceeds and exhaust gas is generated.

When the exhaust valve (4) is opened, the exhaust gas flows to the exhaust gas receiving part (3) through the exhaust duct coupled with the cylinder (1), and then continues to flow to the turbine of the turbocharger (5), and then the exhaust gas Gas is discharged into the atmosphere through exhaust conduits. The turbine 6 of the turbocharger 5 drives a compressor through which fresh air is supplied via an intake port. The compressor delivers pressurized scavenging air to the scavenging conduit leading to the scavenging receiving section. The scavenging in the scavenging conduit passes through the intercooler 7 for cooling the scavenging.

2 is a schematic diagram of an engine fuel or lubricant supply system. The fuel supply system may be installed on an offshore vessel such as an LNG carrier or a container ship.

The fuel supply system includes a fuel storage tank 8 in which fuel, such as lubricant or fuel oil, is stored. In addition, the fuel is a liquefied gas stored under cryogenic conditions.

The feed conduit 9 connects the outlet of the fuel or lubricant storage tank 8 to the inlet of the high pressure pump 40. The feed pump 10 supports the transportation of fuel or lubricant from the storage tank 8 to the inlet of the high pressure pump 40.

The pump 40 pumps fuel or lubricant gas through the supply conduit 18 to the engine. The valve device 19 controls the connection of the fuel / lubricant supply system with a large two-stroke diesel engine.

The pump 40 is provided with two or more pump parts 41, 42, 43 (three pump parts are shown in this embodiment). Each pump portion 41, 42, 43 connects the driving piston 46 to the pump piston 62 to drive the pump piston 62, and the pump piston 62 is slidably disposed in the pump cylinder 61 And a hydraulic power-driven piston 62 slidably disposed in the drive cylinder 45.

The pump piston 62 and the pump cylinder 61 form a positive displacement pump. In one embodiment, the pump piston 62 and the pump cylinder 61 form a so-called low temperature end of the cryogenic pump portion with the pump chamber 63 to pump liquefied gas.

The pump cylinder 61 is connected to the drive piston of the pump parts 41, 42, 43 via the piston rod 49. The drive piston 46 divides the interior of the drive cylinder 45 into a drive chamber 48 and a return chamber 47.

The drive cylinder 45 is connected to the source of the high pressure hydraulic actuator 20. Via a high pressure hydraulic liquid supply conduit 23, for example connected to a pump or pump station. In the illustrated embodiment, the high pressure hydraulic oil supply source 20 includes an electric drive motor 21 that drives the high pressure pump 22. The high pressure pump 22 can be, for example, a positive displacement pump, preferably a variable displacement pump. For redundancy purposes, the high pressure hydraulic oil source 20 in the embodiment includes two high pressure hydraulic pumps 22 each driven by its own electric drive motor 21.

3 is a view showing a state in which the high-pressure pump 40 with three pump parts 41, 42, and 43 equipped with a pump cylinder 61, a drive cylinder 45, and a control valve 24 is raised. The pump parts 41, 42 and 43 are supported by a frame 35 together with an accumulator 53 for equalizing the upper pressure of the high pressure pump 40 and equalizing the lower pressure of the return chamber. The pump parts 41, 42 and 43 are arranged in a compact manner on the frame 35, and there is no spark on the frame 35, and there are only electrical components approved by ATEX, so the device can be used without problems in the ATEX environment. Can be installed.

4 is a schematic representation of a high pressure pump 40 with pump parts 41, 42, 43. Each pump section 41, 42, 43 is connected to the tank via a hydraulic liquid return line 26, and is variable to be connected to each pump section 41, 42, 43 via a hydraulic liquid supply conduit 23 It is connected to a source of high pressure hydraulic liquid comprising a positive displacement pump (22). Each pump section 41, 42, 43 is connected to a supply conduit 18.

Each pump portion 41, 42, 43 includes a hydraulic control valve 24 configured to selectively connect each drive chamber 48 to a source of high pressure hydraulic oil or a tank via a control conduit 25.

Each pump portion 41, 42, 43 includes a drive unit 44 in the form of a linear hydraulic actuator formed by a drive cylinder 45 in which the drive piston 46 is slidably arranged. Return chamber 47 is preferably via flow return chamber supply line, including flow restriction 33 and coupled to accumulator 32, to ensure a stable supply of pressurized hydraulic liquid to return chamber 47 The hydraulic pump 30 is permanently connected to a hydraulic supply source, including a variable displacement pump. Alternatively, the low pressure source is obtained from a high pressure hydraulic system via a pressure reducing valve. In one embodiment, the supply pressure of the hydraulic liquid to the return chamber 47 is significantly lower than the pressure of the hydraulic liquid supplied to the drive chamber 48. Alternatively, the effective pressure surface on the side of the drive piston 46 facing the return chamber 47 can be disposed significantly smaller than the effective pressure surface of the drive piston facing the drive chamber 48. In the latter case, the pressure of the hydraulic oil in the return chamber 47 may be substantially the same as the supply pressure of the hydraulic oil to the drive chamber 48.

Each pump portion (41, 42, 43) includes a pump (60) in the form of a linear positive displacement pump formed by the pump cylinder (61), the pump piston (62) to form a pump chamber (63) in the pump cylinder To accept. The pump chamber 63 is connected to the feed conduit 9 via a first one-way valve 51 that allows only flow to the pressure chamber. The pump chamber 63 is connected to the supply conduit 18 via a second one-way valve 52 that allows only flow from the pressure chamber.

5 is a detailed cross-sectional view of the pump parts 41, 42 and 43 of the high pressure pump 40. The pump portions 41, 42, 43 include a hydraulic linear actuator 44 including a cylinder 45 with a drive piston 46 disposed therein. The drive piston 46 is connected to the piston shaft 47 and is preferably formed in one device with the piston shaft 47. The piston rod 49 and the driving piston 46 are provided with a bore 58 for receiving the rod 57 of the position sensor 56. The signal from the position sensor 56 is transmitted to the electronic control device 70. The drive piston 46 divides the interior of the drive cylinder 45 into a drive chamber 48 and a return chamber 47. In Fig. 5, the return chamber 47 cannot be recognized because the drive piston 46 has reached the end of the drive stroke. The drive chamber 48 is connected to the hydraulic control valve 24 via a bore 25. The return chamber 47 is permanently connected to the hydraulic source through the bore 31.

The piston rod 47 of the linear hydraulic actuator 44 is connected to the piston rod 62 of the cryogenic pump 60 (although a conventional linear positive displacement pump for pumping the non-cryogenic liquid 60) Even if it could be good). The connection of the piston rod 49 and the pump piston 62 is established by the connector piece 54 in such a way that the piston rod 49 and the pump piston 62 move in unison. The drive cylinder 45 is connected to the pump cylinder 61 by a bolt connection 55. The pump 60 is provided with an outlet connecting the pump chamber 63 to the transfer conduit 50.

9 is a schematic representation of a control system in the form of an electronic control device 70 for controlling the operation of the high pressure pump 40.

The electronic control device 70 accommodates the lubricant pressure set point 71 fuel. The pressure set point 71 is transferred to the first sum point 72. At the first summation point 72, the measured gas pressure is subtracted, and the difference between the pressure setpoint 71 and the measured gas pressure at the pump 40 outlet is transmitted to the PI controller 74 which is part of the feedback control loop. do. The pressure setpoint 71 is transmitted to the feed-forward piston ratio gain device 78. The signal from the feed-forward piston ratio gain device 78 is compared to the signal from the PI controller 74 at the second summation point 76.

The gas pressure measured for the fuel or lubricant supplied to the first summation point 72 can be based on the measurement of the pipe volume in the engine, ie the pressure in the valve device 19 downstream. The valve arrangement 19 is a double block and bleed valve arrangement that receives the flow of fuel or lubricant from the supply conduit 18. The measured pressure of the fuel or lubricant is filtered in filter 86.

The comparison result at the second summing point 76 is transmitted to the high pressure hydraulic actuator 20. On the basis of the signal, the high pressure hydraulic oil supply source 20 delivers the hydraulic liquid having the correct pressure to the high pressure pumping unit 40.

The electronic control device 70 receives a signal indicating the position of the driving piston 46 and processes the position signal in the piston monitoring device 92. The piston monitoring device 92 is connected to the piston actuation strategy device 90. Details of the operation of the piston monitoring device 92 and the piston operation strategy device 90 are described in more detail below. The signal from the piston actuation strategy device 90 is transmitted to the control valve 24 of the high pressure pump 40 to actuate the drive piston 46.

The actuation of the drive piston 46 causes fuel or lubricant to be pumped through the supply conduit 18.

The main pressure control of the electronic control device 70 is feed-forward. The PI (proportional integral) controller corrects nonlinearity and supports transients.

The pressure of the fuel or lubricant is controlled by itself by setting the hydraulic pressure supply pressure to the pump parts (41, 42, 43). The pressure control is on the hydraulic side and does not need to operate on the gas side. This system makes it impossible for the fuel or lubricant to reach too high a pressure when the hydraulic pressure is properly controlled.

The drive piston 46 is controlled through a control strategy rather than a working part of pressure control.

Each pump section 41, 42, 43 can be individually controlled. Therefore, various piston strategies and various operating conditions can be implemented. Further, since it is possible to change the pump portions 41, 42, 43 from three to two between two strokes, it is possible to individually execute the pump portions 41, 42, 43, thereby providing redundancy.

The return speed can be greater than the forward (pump) speed, so overlapping is possible when operating with only two pump sections. The overlap between the pump sections 41, 42, 43 can be adjusted as needed to reduce pressure spikes.

The end position of the pump stroke can vary over time to distribute wear to the area of the pump cylinder 61, as opposed to high wear in a fixed position on the cylinder.

Very low inertia and other factors that negatively affect the dynamic response allow little or no pressure overshoot for sudden shutdowns (piston stops).

The control valve 24 may be a hydraulic control valve or an electronic control valve. In the above embodiment, the control valve 24 is a hydraulic control valve, and an electronically controlled solenoid valve (not shown) that controls the hydraulic control signal to the control valve 24 is provided. The electronic control solenoid valve receives an electronic control signal from the electronic control device 70.

The electronic control device 70 is configured to selectively connect the drive chamber 48 of the pump portions 41, 42, 43 to the high pressure hydraulic oil supply source 20 or tank.

The electronic control device 70 is configured to start the pump stroke of the drive piston when the pump stroke of the other drive piston 47 approaches its end, so that there is a small overlap between the end pump stroke and the start pump stroke. In one embodiment, the electronic control device 70 is configured to operate each drive cylinder substantially continuously, preferably with little overlap.

Thus, it is possible to achieve a substantially stable flow of LNG with a pressure vaporizer, as shown in FIGS. 6 and 7 without significant pressure fluctuations.

6, 7 and 8 show typical operation of the high pressure pump 40. The thin continuous line represents the pump portion 41, the thick continuous line represents the pump portion 42, and the dotted line represents the pump portion 43. 6 is a graph showing the movement of the driving piston 46 / pump piston 62. As can be seen from the graph, the pump stroke start of the next pump section starts just before the pump stroke of the currently operating pump section. FIG. 7 shows the resulting pressure consisting of the pressure output from the transport conduits 50 of the three pump sections 41, 42, 43. The resulting pressure is virtually constant and unchanged.

Fig. 8 shows the velocity profile of the pump section which clearly shows that the speed of the return stroke is significantly higher than the speed of the pump stroke, thus allowing overlap between the pump sections even if only two of the three or more pump sections are in use. .

In one embodiment, the electronic control device 70, in particular in the piston actuation strategy device 90, is characterized by the dynamics of the termination pump stroke to obtain a substantially constant flow of high pressure liquefied gas from the high pressure pump to the high pressure vaporizer 14 It is configured to take into account the dynamics of the starting pump stroke.

In one embodiment, the electronic control device 70 determines when the pump stroke of one of the pump portions 41, 42, 43 should start and when the pump stroke of any drive device 41, 42, 43 ends It is configured to determine if it should be. Therefore, it is possible to precisely control the point at which the pump stroke starts and particularly the point at which the pump stroke ends, with the piston strategy device 90, preferably with the piston monitoring device 92.

In one embodiment, the electronic control device 70 is configured to operate the drive piston of the other pump portion that functions when one of the pump portions 41, 42, 43 fails. Accordingly, redundancy is achieved, and the pump operation may continue even if one of the pump units 41, 42, or 43 fails.

In one embodiment, the electronic control device 70 is a drive piston 46 in which the drive chamber 48 is separated from the high pressure hydraulic oil supply source 20 in relation to the size of the liquefied gas flow from the high pressure pump 40 to the high pressure vaporizer. It is configured to adjust the position of. Accordingly, the position at which the pump stroke is reversed can be controlled regardless of the speed and the resulting inertia of the drive piston 46 and pump piston 62.

According to one embodiment, the electronic control device 70 drives the drive chamber of the associated drive piston 46 from the high pressure hydraulic oil supply source 20 in a direction opposite to the drive stroke direction when the flow of fuel or lubricant from the high pressure pump to the engine increases. The 48 is configured to adjust the position of the drive piston 46 from which it is separated, and the electronic control device 70 is provided with a high pressure hydraulic oil supply source in the direction of the drive stroke direction when the flow of fuel or lubricant from the high pressure pump to the engine decreases ( The drive chamber 48 of the associated drive piston 46 from 20 is configured to adjust the position of the drive piston 46 to be separated. This is illustrated in FIGS. 10 and 11.

10 shows the effect of the increased speed of the drive piston 46 and pump piston 62 on the end position of the drive / pump stroke. The thin continuous line represents the pump portion 41, the thick continuous line represents the pump portion 42, and the dotted line represents the pump portion 43. The electronic control device 70 controls the hydraulic control valve 24 to connect the drive chamber 48 to the tank when the drive piston reaches the 80 mm stroke, regardless of the load / size of the liquefied gas flow delivered by the high pressure pump 40. ). Due to the inertia and high speed, the stop / reverse position of the drive piston 46 varies from 85 mm at 25% load to 89 mm at 50% load and 98 mm at 100% load.

FIG. 11 is an electronic control device for correcting the increased speed of the drive piston 46 / pump piston 62 by connecting the drive chamber 48 to the tank in the short stroke when the load is high and in the long stroke when the load is low. It is a graph showing the effect of 70). As can be seen from the graph, the electronic control device 70 can accurately control the end position of the drive / pump stroke in this way.

In the example of the graph above, the signal for connecting the drive chamber 48 to the tank for 25% load of the next drive cylinder (i.e., 25% of the maximum capacity of the high pressure pump 40), the previous cylinder is 75 mm into the drive chamber. When it comes out. The drive chamber of the "old" drive cylinder is connected to the tank when it is 93 mm into the drive chamber. The connection of the high-pressure supply of the next drive cylinder "Signal On" and the tank connection of the "Previous" cylinder "Signal Off" are shown in Table 1 below.

25% load 45% load 70% load 100% load Signal on 75 mm 75 mm 75 mm 75 mm Signal off 93 mm 86 mm 83 mm 80 mm Stop position 97 mm 97 mm 97 mm 97 mm

Thus, the position of the drive piston 46 is measured during the drive stroke, the drive piston 46 is activated when the drive piston 46 is in the return position, and the drive piston 46 is at the speed of the drive piston 46. It stops at the determined position. Of course, it is still possible to program the electronic control unit 72 to intentionally change the starting position to reduce wear of the pump cylinder 61.

The electronic control device 70 is driven according to an algorithm or plan, or optionally, to distribute the position where the pump piston 62 is reversed in the stroke region of the pump piston 62 to reduce wear of the pump cylinder 61. The drive chamber 48 of the piston 46 is configured to adjust the position of the drive piston 46 separated from the high pressure hydraulic oil supply source 20. It is known that the wear of the pump cylinder 61 is highest at the position where the pump stroke ends. By changing the position at which the pump stroke ends, the wear of the pump cylinder 61 can be distributed over a larger area and the life of the pump cylinder 61 can be significantly increased.

In one embodiment, the electronic control device 70 is configured to control the operation and stop of each drive piston 46 independently of controlling the pressure of hydraulic oil supplied to the drive chamber 48. Thus, the control strategy for the operation of the drive piston 46 can be optimized by the electronic control device 70 independently of the pressure control.

The invention has been described in conjunction with various embodiments herein. However, other variations on the disclosed embodiments can be understood and practiced by those skilled in the art practicing the invention as claimed from the study of the drawings, the disclosure and the appended claims. In this claim, the word “comprising” does not exclude other elements or steps, and “one” or “one” does not exclude a plurality. The electronic control device may be formed by a combination of separate electronic control devices. The mere fact that certain options are cited in different dependent claims does not indicate that combinations of those used as options cannot be advantageously used. Reference signs used in the claims should not be construed as limiting the scope.

8 Fuel storage tank 14 High pressure carburetor
24 Control valve 40 High pressure pump
45 drive cylinder 46 drive piston
47 Return chamber 48 Drive chamber
62 Pump Piston 70 Electronic Control Unit

Claims (19)

In the cryogenic pump (40) for pumping cryogenic fuel,
The pump 40 includes two or more pump parts 41, 42, 43, and each of the pump parts 41, 42, 43 is driven piston 46 to drive the pump piston 62 It includes the pump piston 62 coupled to the pump piston 62 and slidably disposed in the pump cylinder 61 and the driving piston 46 of hydraulic power slidably disposed in the drive cylinder 45 and,
The pump piston 62 and the pump cylinder 61 form a low temperature end of the cryogenic pump portion together with the pump chamber 63 to pump liquefied gas,
The drive cylinder 45 includes a drive chamber 48 and a return chamber 47,
Includes variable displacement pump 22,
Each control valve 24 associated with each of the pump parts (41, 42, 43),
Each of the control valve 24 is connected to the variable displacement pump 22, the tank,
Each of the control valves 24 is connected to the drive chamber 48 of the associated drive cylinder 45 to control the flow of hydraulic oil to / from the drive chamber 48, and the drive chamber 48. Connected to the variable displacement pump 22 or the tank,
Each of the drive cylinders 45 is provided with a position sensor 56 for detecting the position of the drive piston 46 in the associated drive cylinder 45,
Further comprising an electronic control device 70 for receiving a signal from the position sensor 56, the control valve 24 is connected to the electronic control device 70, at least one of the electronic control device 70 Is configured to selectively connect the drive cylinder 45 of the pump unit 41, 42, 43 to the variable displacement pump 22 or the tank by the operation of the control valve 24,
The electronic control device 70,
After actuating the driving piston 46 at a return position for a driving stroke driving the pump piston 62, the driving piston 46 is stopped for a return stroke,
The position of the driving piston 46 is measured during the driving stroke,
In order to compensate for the increase in the speed of the driving piston 46, if the speed of the driving piston 46 is high during the driving stroke, the driving piston 46 is stopped at a position closer to the return position after a short stroke and the When the speed of the driving piston 46 is low, by stopping at a position further away from the return position after a longer stroke, the driving piston 46 is stopped at a position determined according to the speed of the driving piston 46 so that,
Cryogenic pump characterized in that it is configured. The method according to claim 1,
The return chamber (47) is a cryogenic pump, characterized in that connected to a hydraulic oil supply source (30) of a pressure lower than the pressure delivered by the variable displacement pump (22). The method according to claim 1,
The electronic control device 70 is configured to start the pump stroke of the other drive piston 46 when the pump stroke of the drive piston 46 approaches its end, so that there is a small overlap between the end pump stroke and the start pump stroke. Cryogenic pump, characterized in that. The method according to claim 3,
The electronic control device (70) is configured to take into account the dynamics of the end pump stroke and the dynamics of the start pump stroke to obtain a constant flow for high pressure fuel from the pump (40). The method according to claim 4,
The electronic control device (70) is a cryogenic pump characterized in that it is configured to continuously operate each of the drive cylinders (45). The method according to claim 4,
The electronic control device (70) is a cryogenic pump, characterized in that each drive cylinder (45) is configured to operate continuously with little overlap. The method according to claim 1,
The electronic control device 70 includes the drive piston 46 in which the drive chamber 48 is separated from the variable displacement pump 22 in relation to an increase in the flow size of the fuel pumped by the pump 40. It is configured to adjust the position of the cryogenic pump. The method according to claim 1,
When the flow of fuel pumped by the pump 40 increases, the electronic control device 70 drives the drive chamber of the associated drive piston 46 from the variable displacement pump 22 in a direction opposite to the drive stroke direction. Cryogenic pump, characterized in that configured to adjust the position of the drive piston (46) is separated (48). The method according to claim 7,
The electronic control device 70 is the drive chamber of the associated drive piston 46 from the variable displacement pump 22 in the direction of the drive stroke direction when the flow of fuel pumped by the pump 40 decreases 48) is a cryogenic pump characterized in that it is configured to adjust the position of the drive piston 46 is separated. The method according to claim 1,
The electronic control device 70 is driven according to an algorithm or plan or arbitrarily to distribute a position where the pump piston 62 reverses a part of the stroke of the pump piston 62 for the purpose of reducing wear of the pump cylinder 61. Cryogenic pump, characterized in that it is configured to adjust the position of the piston (46). The method according to any one of claims 1 to 10,
The electronic control device (70) is configured to control the pressure of the fuel leaving the pump by controlling the pressure of the hydraulic oil supplied to the drive chamber (48). The method according to claim 11,
The electronic control device (70) is a cryogenic pump, characterized in that it is configured to use the desired pressure of the fuel leaving the pump with a feed-forward function for controlling the pressure of the hydraulic oil supplied to the drive chamber (48). The method according to claim 11,
The electronic control device (70) is a cryogenic pump, characterized in that it is configured to use the measured pressure of the fuel leaving the pump as a feedback function for controlling the pressure of the hydraulic oil supplied to the drive chamber (48). The method according to claim 11,
The electronic control device (70) is a cryogenic pump, characterized in that configured to control the operation and stop of each driving piston (46) regardless of the pressure of the hydraulic oil supplied to the driving chamber (48). The method according to claim 12,
The electronic control device (70) is a cryogenic pump, characterized in that it is configured to use a signal indicative of the position of the drive piston (46) to control the operation and stop of the drive piston (46). A large two-stroke turbocharging compression ignition internal combustion engine, comprising a cryogenic pump (40) according to claim 1 to supply fuel to the engine. In the method for controlling the pump piston operation of the cryogenic pump (40),
The pump 40 includes two or more pump parts 41, 42, 43 that are individually operated, and each of the pump parts 41, 42, 43 is driven piston to drive the pump piston 62 The pump piston 62 coupled to the pump piston 62 and slidably disposed in the pump cylinder 61 and the drive piston 46 of hydraulic power slidably disposed in the drive cylinder 45 ),
The pump piston 62 and the pump cylinder 61 form a low temperature end of the cryogenic pump portion together with the pump chamber 63 to pump liquefied gas,
The above method,
Operating the drive piston (46) in a return position for a drive stroke driving the pump piston (62), and then stopping the drive piston (46) for a return stroke;
Measuring the position of the drive piston 46 during the drive stroke;
In order to compensate for the increase in the speed of the driving piston 46, if the speed of the driving piston 46 is high during the driving stroke, the driving piston 46 is stopped at a position closer to the return position after a short stroke and the When the speed of the driving piston 46 is low, by stopping at a position further away from the return position after a longer stroke, the driving piston 46 is stopped at a position determined according to the speed of the driving piston 46 The method comprising the steps; comprising. The method according to claim 17,
The driving piston (46) is operated sequentially, and the operation of the next driving piston (46) is characterized in that it takes place immediately before the stop of the currently operating driving piston (46). The method according to claim 17 or 18,
Further comprising the step of supplying the high pressure hydraulic oil to the drive piston 46, the pressure of the fuel leaving the pump 40 is characterized in that it is controlled by controlling the pressure of the hydraulic oil supplied to the drive piston (46) Way.

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