JP6902066B2 - Fuel or lubrication pump for large 2-stroke compression ignition internal combustion engines - Google Patents

Description

The present disclosure relates to a fuel or lubrication pump for a large low speed 2-stroke uniflow compression ignition internal combustion engine.

Typically, a large two-stroke uniflow turbocharged compression ignition internal combustion crosshead engine is used as a propulsion system for a large ship or as a prime mover for a power plant. Its overwhelming size, weight, and output are quite different from general internal combustion engines, and large 2-stroke turbocharged compression ignition internal combustion engines are classified as unique.

Large two-stroke compression ignition internal combustion engines have traditionally been operated on liquid fuels such as fuel oil or heavy oil. However, due to growing environmental concerns, developments have been made towards the use of alternative fuels such as gas, methanol, coal slurries and petroleum coke.

These alternative types of fuel have characteristics that are difficult to handle with conventional fuel pumps. Some have an abrasion effect such as coal slurry, some have very low lubrication performance such as gasoline, and some have extremely low temperature such as liquefied gas which is an extremely low temperature gas.

Patent Document 1 discloses a cylinder lubrication system having a plurality of cylinder oil pumps. Each cylinder oil pump is provided with a drive piston that is coupled with multiple weighing plungers.

Therefore, it is necessary to provide a pump that can handle these alternative fuels.

WO2016 / 015732

An object of the present invention is to provide a pump that overcomes or at least alleviates the problems described above.

The above and other objectives are achieved by the characteristics of the independent claims. Further implementation forms will be apparent in the dependent claims, specification, and drawings.

According to the first aspect, there are two or more pump units, each of which is a pump piston slidably disposed on a pump cylinder and a liquid slidably disposed on a drive cylinder. A pump is provided for pumping cryogenic fuel, comprising a pressure driven piston, the drive piston being coupled to the pump piston to drive the pump piston.

By providing a pump in which each pump piston is actuated by a linear hydraulic actuator, any suitable pump piston is driven in a completely flexible manner, independent of crankshaft limitations and inertia. Allows for pump piston operating features that are perfectly adapted to the pumped liquid.

According to the first possible embodiment of the first aspect, the pump controls the flow of hydraulic fluid to and from the drive cylinders of one or more pump units in order to control the flow of hydraulic fluid from the drive cylinders. Further comprising a source of high pressure hydraulic fluid and at least one hydraulic pressure control valve connected to the tank, the source of high pressure hydraulic fluid is preferably a source of variable and controllable pressure levels.

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

According to a third possible embodiment of the first aspect, the drive chamber is connected to a hydraulic pressure control valve and the return chamber is to a source of hydraulic fluid whose pressure is lower than the pressure of the source of high pressure hydraulic fluid. It is preferably always connected.

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

According to a fifth possible embodiment of the first aspect, the fuel supply system further comprises an electronic control unit that receives a signal from the position sensor, and at least one hydraulic control valve is an electron coupled to the electronic control unit. It is a control valve.

According to a sixth possible embodiment of the first aspect, the electronic control unit is configured to selectively connect the drive chamber of the pump unit to a source or tank of high pressure hydraulic fluid.

According to a seventh possible embodiment of the first aspect, the electronic control unit sets the pump stroke of the drive piston to the pump stroke that ends and begins with the pump stroke of another drive piston approaching the end point. It is configured to start when there is a small overlap between and. Therefore, a substantially stable flow of fuel or lubricating fluid leaving the pump can be achieved without large pressure fluctuations.

According to an eighth possible embodiment of the first aspect, the electronic control unit is the power and pump at the end of the pump stroke in order to obtain a substantially constant flow of high pressure fuel or high pressure lubricating fluid from the pump. -It is configured to take into account the power at the start of the stroke.

According to a ninth possible embodiment of the first aspect, the electronic control unit is to determine when to start one pump stroke in the drive cylinder / unit, and any in the drive cylinder. It is configured to determine when the pump stroke should end. Therefore, the point at which the pump stroke begins and, in particular, where the pump stroke ends can be precisely controlled.

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

According to the eleventh possible embodiment of the first aspect, the electronic control unit is configured to operate the drive piston of the remaining functioning pump unit if one of the pump units fails. Therefore, redundancy is obtained and the pumping operation can be continued even if one of the pump units fails.

According to a twelfth possible embodiment of the first aspect, the electronic control unit is such that the drive cylinders of the remaining functioning pump units are operated substantially continuously, preferably with a small overlap. It is configured to operate the drive pistons of the remaining functioning pump units.

According to the thirteenth possible embodiment of the first aspect, the electronic control unit has a drive chamber from a source of high pressure hydraulic fluid in relation to the magnitude of the flow of liquefied gas from the high pressure pump to the high pressure vaporizer. It is configured to adjust the position of the drive piston to be disconnected. Therefore, the position where the pump stroke reverses can be kept at the same position regardless of the speed of the pump piston and the drive piston and the inertia generated.

According to the fourteenth possible embodiment of the first aspect, the electronic control unit disconnects the drive chamber of the associated drive piston from the source of high pressure fluid when the flow of fuel or lubricating fluid from the pump increases. It is configured to adjust the position of the drive piston in the direction opposite to the direction of the drive stroke.

According to a fifteenth possible embodiment of the first aspect, the electronic control unit disconnects the drive chamber of the associated drive piston from the source of high pressure fluid when the flow of fuel or lubricating fluid from the pump is reduced. It is configured to adjust the position of the drive piston in the direction of the drive stroke.

According to the sixteenth possible embodiment of the first aspect, the electronic control unit disperses the position where the pump piston reverses over the stroke region of the pump piston in order to reduce wear on the pump cylinder. An algorithm, plan, or randomization is configured to adjust the position of the drive piston in which the drive chamber of the relevant drive piston is disconnected from the high pressure fluid source.

According to the seventeenth possible embodiment of the first aspect, the electronic control unit controls the pressure of the hydraulic fluid supplied to the drive chamber, thereby delivering and pumping the pressure of the fuel or lubricating fluid. Is configured to control. Therefore, effective and immediate reaction control of the pressure of the pumped fuel or lubricating fluid is realized.

According to an eighteenth possible embodiment of the first aspect, the electronic control unit is a desired fuel or lubricating fluid to be pumped in a feedforward function for controlling the pressure of the hydraulic fluid supplied to the drive chamber. Configured to use pressure. By using feedforward control of the pressure of the liquefied gas via the hydraulic pressure, more rapid and stable control of the pressure of the fuel or lubricating liquid to be pumped can be realized.

According to a nineteenth possible embodiment of the first aspect, the electronic control unit measures the pumped fuel or lubricating fluid in a feedback function to control the pressure of the hydraulic fluid supplied to the drive chamber. Configured to use pressure. Therefore, non-linearity and transient fluctuations can be adapted by the control system.

According to the twentieth possible embodiment of the first aspect, the electronic control unit controls the operation and deactivation of each drive piston independently of controlling the pressure of the hydraulic fluid supplied to the drive chamber. It is configured to do. Therefore, the control method for the operation of the drive piston can be optimized by the electronic control unit independently of the pressure control.

According to the 21st possible embodiment of the first aspect, the electronic control unit is configured to use a signal indicating the position of the drive piston to control the operation and deactivation of the drive piston.

According to the second aspect, there is provided a compression ignition internal combustion engine with a large two-stroke turbocharger having a pump according to the first aspect and any possible embodiment thereof.

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

According to a fourth aspect, there is provided a method for pumping fuel or lubricating fluid to an internal combustion engine in order to inject high pressure gas into the engine. This method
Storing fuel or lubricating fluid in storage tanks
Provided with pumping fuel or lubricating fluid to the engine using a pump.
The pump comprises two or more pump units, each pump piston slidably located in the pump cylinder and a liquid coupled to the pump piston to drive the pump piston. Equipped with a pressure driven piston, the method is further
To supply a high-pressure hydraulic fluid to the drive cylinder to drive the drive piston,
It comprises controlling the pressure of the fuel or lubricating fluid leaving the high pressure pump by controlling the pressure of the hydraulic fluid supplied to the drive cylinder.

According to the first possible embodiment of the fourth aspect, the method activates one of the drive pistons for a drive stroke and then deactivates that one drive piston for a return stroke. And to prepare further.

According to the second possible embodiment of the fourth aspect, the pump piston and the drive piston are connected to each other and move simultaneously.

According to a third possible embodiment of the fourth aspect, the method is to combine the pump stroke of a drive piston with a pump stroke that ends and a pump stroke that begins with the pump stroke of another drive piston approaching the end point. Further prepared to start when there is a small overlap between them.

According to a fourth possible embodiment of the fourth aspect, the method is power and pump at the end of the pump stroke in order to obtain a substantially constant flow of fuel or lubricating fluid from the pump to the engine. Further prepare to take into account the power at the beginning of the stroke.

According to a fifth possible embodiment of the fourth aspect, the method further comprises operating each drive cylinder substantially continuously, preferably with a small overlap.

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

In the following details of the disclosure, the invention will be described in more detail with reference to exemplary embodiments shown in the drawings.

Vertical view of a large two-stroke diesel engine according to an exemplary embodiment The figure which shows the fuel supply system which supplies high pressure natural gas from the LNG storage tank to the large two-stroke diesel engine of FIG. Elevation view of the high pressure pump of the fuel injection system of FIG. The figure which shows the high pressure pump of FIG. Detailed cross-sectional view of the pump unit of the high-pressure pump of FIG. A graph illustrating the operation of the high-pressure pump of FIG. A graph illustrating the operation of the high-pressure pump of FIG. A graph illustrating the operation of the high-pressure pump of FIG. The figure which shows the control system for controlling the high pressure pump of FIG. Graph exemplifying the movement of the piston of the high pressure pump of FIG. 3 at various speeds. Graph exemplifying the movement of the piston of the high pressure pump of FIG. 3 at various speeds.

In the following detailed description, a fuel supply system for a large two-stroke low speed turbocharged compression ignition internal combustion engine with a crosshead will be described with reference to exemplary embodiments, the internal combustion engine being turbocharged. It can also be another type, such as a 2-stroke otto, a 4-stroke otto or diesel, with or without turbocharger, with exhaust gas recirculation or selective contact reduction or without exhaust gas recirculation or selective contact reduction. I want to be understood. Further, a pump for supplying fuel or a lubricant to a large two-stroke low-speed turbocharged compression ignition internal combustion engine having a crosshead is described with reference to an exemplary embodiment, wherein the internal combustion engine is a turbo. It can also be another type, such as a two-stroke otto, a four-stroke otto, or diesel, with or without a turbocharger, with exhaust gas recirculation or selective contact reduction, or without exhaust gas recirculation or selective contact reduction.

FIG. 1 shows a large low speed turbocharged 2-stroke diesel engine with rotating wheels and a crosshead. In this exemplary embodiment, the engine is an in-line 6-cylinder engine. A large low speed turbocharged 2-stroke diesel engine typically has 4 to 14 cylinders in series and is supported by a cylinder frame supported by an engine frame 6. This engine can be used, for example, as a stationary engine that operates a main engine of a ship or a generator of a power plant. The total output of this engine can be, for example, in the range of 1,000 to 110,000 kW.

In this exemplary embodiment, the engine is a two-stroke uniflow type compression ignition engine having a scavenging port in the lower region of the cylinder 1 and a central exhaust valve 4 above the cylinder liner 1. The scavenging air is sent from the scavenging receiver 2 to the scavenging port of each cylinder 1. The piston of the cylinder liner 1 compresses the scavenging air, for example, high pressure fuel such as gas fuel is injected through the fuel valve in the cylinder cover, combustion occurs, and exhaust gas is generated.

When the exhaust valve 4 is opened, the exhaust gas flows to the exhaust gas receiver 3 through the exhaust duct associated with the cylinder 1 and proceeds to the turbine of the turbocharger 5, from which the exhaust gas flows out to the atmosphere through the exhaust pipe. The turbine of the turbocharger 5 drives a compressor supplied with outside air through an air inlet. The compressor delivers the compressed scavenging air to a scavenging tube that leads to the scavenging receiver 2. The scavenging air in the scavenging pipe passes through the intercooler 7 and is cooled.

FIG. 2 is a simplified diagram of an engine fuel or lubricating fluid supply system. The fuel supply system can be installed on a ship such as an LNG carrier or a container ship.

The fuel supply system includes a fuel storage tank 8 for storing fuel or lubricating fluid, such as fuel oil. Alternatively, the fuel is a liquefied gas stored in a cryogenic state.

The feed pipe 9 connects the outlet of the fuel or lubricating liquid storage tank 8 to the inlet of the high pressure pump 40. The feed pump 10 assists in transferring fuel or lubricating fluid from the storage tank 8 to the inlet of the pump 40.

The pump 40 pumps fuel or lubricating fluid to the engine via the supply pipe 18. The valve device 19 controls the connection between the fuel / lubricant supply system and the large two-stroke diesel engine.

The pump 40 is provided with two or more pump units 41, 42, 43 (three pump units are shown in this embodiment). Each pump unit 41, 42, 43 has a pump piston 62 slidably arranged in the pump cylinder 61 and a drive piston 46 coupled to the pump piston 62 to drive the pump piston 62. Includes a hydraulically driven piston 46 slidably arranged in a drive cylinder 45 having a.

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 cold end of a cryogenic pump unit having a pump chamber 63 for pumping liquefied gas.

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

The drive cylinder 45 is connected to a pump or pump station via a high pressure hydraulic fluid supply source 20, for example, a high pressure hydraulic fluid supply pipe 23. In the embodiments shown, the high pressure hydraulic fluid 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 positive displacement pump. In one embodiment, for redundancy purposes, the source of the high pressure hydraulic fluid includes two high pressure hydraulic pumps 22, each driven by its electric drive motor 21.

FIG. 3 shows a high-pressure pump 40 having three pump units 41, 42, 43, each having a pump cylinder 61, a drive cylinder 45, and a control valve 24, supported by a frame 35. FIG. 5 is an elevational view shown with an accumulator 53 for homogenizing the high pressure and homogenizing the low pressure in the return chamber. The pump units 41, 42, 43 are compactly arranged on the frame 35, and the components on the frame 35 have only ATEX-approved electrical components that are non-sparking components, so the unit is It can be installed without any problem in the ATEX environment.

FIG. 4 is a diagram showing the high pressure pump 40 together with its pump units 41, 42, 43. Variable capacities of the pump units 41, 42, 43 are connected to the tank via the hydraulic fluid return line 26 and are connected to the respective pump units 41, 42, 43 via the hydraulic fluid supply pipe 23. It is connected to a source of high pressure hydraulic fluid, including a positive displacement pump 22. Each pump unit 41, 42, and 43 is connected to a supply pipe 18.

Each pump unit 41, 42, 43 includes a hydraulic pressure control valve 24 configured to selectively connect each drive chamber 48 to a high pressure hydraulic fluid supply source or tank via a control pipe 25.

Each pump unit 41, 42, 43 comprises 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 therein. The return chamber 47 is always connected to the hydraulic pressure supply source. The hydraulic supply source includes a hydraulic pump 30, for example a variable displacement positive displacement pump, via a return chamber supply line 31, which preferably includes a flow rate limit 33 and is pressurized to the return chamber 47. It is coupled to the accumulator 32 to ensure a stable supply of the working fluid. Alternatively, a low pressure source is obtained from the high pressure hydraulic system via a pressure reduction valve. In one embodiment, the pressure of the hydraulic fluid supplied to the return chamber is significantly lower than the pressure of the hydraulic fluid supplied to the drive chamber 48. Alternatively, the effective pressure surface on the side surface of the drive piston 46 facing the return chamber 47 may be arranged so as to be 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 fluid in the return chamber 47 can be substantially equal to the pressure of the hydraulic fluid supplied to the drive chamber.

Each pump unit 41, 42, 43 comprises a pump 60 in the form of a linear positive displacement pump formed by a pump cylinder 61 that receives a pump piston 62 therein to form a pump chamber 63. The pump chamber 63 is connected to the feed pipe 9 via a first one-way valve 51 that only allows flow to the pressure chamber 63. The pump chamber 63 is connected to the supply pipe 18 via a second unidirectional valve 52 that allows only flow from the pressure chamber 63.

FIG. 5 is a detailed cross-sectional view of the pump units 41, 42, and 43 of the high-pressure pump 40. Pump units 41, 42, 43 include a hydraulic linear actuator 44 including a cylinder 45 in which a drive piston 46 is located. The drive piston 46 is preferably integrally connected to the piston shaft 47. The piston rod 49 and the drive piston 46 are provided with holes 58 for receiving the rod 57 of the position sensor 56. The signal of the position sensor 56 is sent to the electronic control unit 70. The drive piston 46 divides the inside of the drive cylinder 45 into a drive chamber 48 and a return chamber 47. In FIG. 5, since the drive piston 46 has reached the end point of the drive stroke, the return chamber cannot be confirmed. The drive chamber 48 is connected to the hydraulic pressure control valve 24 via the hole 25. The return chamber 47 is always connected to the hydraulic pressure supply source through the hole 31.

The piston rod 47 of the linear hydraulic actuator 44 is connected to the piston rod 62 of the ultra-low temperature pump 60 (the pump 60 may be a normal linear positive displacement pump that pumps a non-ultra-low temperature liquid). The connection between the piston rod 49 and the piston rod 62 is established by the connector piece 54 so that the piston rod 49 and the piston rod 62 move integrally. The drive cylinder 45 is connected to the pump cylinder 61 by a bolt connection 55. The pump 60 is provided with an outlet for connecting the pump chamber 63 to the transfer pipe 50.

FIG. 9 is a diagram showing a control system in the form of an electronic control unit 70 for controlling the operation of the high pressure pump 40.

The electronic control unit 70 receives the fuel or lubricating fluid pressure setting point 71. The pressure setting point 71 is sent to the addition point 72. The pressure measured at the first addition point 72 is subtracted and the difference between the set point and the pressure measured at the outlet of the pump 40 is sent to the PI controller 74, which is part of the feedback control loop.

The pressure setting point is sent to the feedforward piston ratio gain unit 78. The signal from the feedforward piston ratio gain unit 78 is compared to the signal from the PI controller 74 at the second addition point 76.

The measured fuel or lubricating pressure sent to the first addition point 72 can be based on the measured pressure in the pipe volume of the engine, i.e. downstream of the valve device 19. The valve device 19 is a two-wheel block and is a bleed valve device that receives a flow of fuel or lubricating fluid from the supply pipe 18. The measured fuel or lubricating pressure is filtered by the filter 86.

The result of the comparison at the second addition point 76 is sent to the high pressure hydraulic fluid supply source 20. Based on the signal, the high pressure hydraulic fluid supply source 20 delivers the hydraulic fluid with the modified pressure to the high pressure pump unit 40.

The electronic control unit 70 receives a signal indicating the position of the drive piston, and the piston supervision unit 92 processes this position signal. The piston supervision unit 92 is coupled to the piston operating method unit 90. Details of the operation of the piston supervision unit 92 and the piston operating method unit 90 will be shown and described in more detail below. The signal of the piston operating method unit 90 is sent to the control valve 24 of the high pressure pump 40 to operate the drive piston 46.

By operating the drive piston 46, fuel or lubricating liquid is pumped through the supply pipe 18.

The main pressure control of the electronic control unit 70 is feedforward. The PI (Proportional Integral) controller compensates for non-linearity and assists against transient fluctuations.

The pressure of the fuel or lubricating liquid is automatically controlled by setting the hydraulic feed pressure to the pump units 41, 42, 43. The pressure control is performed on the hydraulic side and does not need to be performed on the gas side. If the hydraulic pressure is properly controlled, it is unlikely that the fuel or lubricating fluid pressure will be too high in this system.

The drive piston 46 is controlled via a control method that is not an active part of pressure control.

Each pump unit 41, 42, 43 can be individually controlled. Therefore, it is possible to operate under different piston methods and various operating conditions. Furthermore, since it is possible to change from three pump units 41, 42, 43 to two pump units in two strokes, the possibility of operating the pump units 41, 42, 43 individually is redundant. provide.

The speed of return can be faster than the speed of forward (pump), allowing overlap when operating only two pump units. The overlap between the pump units 41, 42, 43 can be adjusted according to the need to reduce pressure spikes.

The final position of the pump stroke can change over time in order to disperse the wear over the region of the pump cylinder 61, as opposed to the high wear occurring at the fixed position of the cylinder.

The system causes little or no excessive pressure, even during a sudden shutdown (piston stop). This is due to very low inertia and other factors that negatively affect the dynamic response.

The control valve 24 can be a hydraulic pressure control valve or an electronically controlled valve. The control valve 24 is a hydraulic pressure control valve. In the present embodiment, an electronically controlled solenoid valve (not shown) is provided to control the hydraulic pressure control signal to the control valve 24. The electronically controlled solenoid valve receives an electronic control signal from the electronic control unit 70.

The electronic control unit 70, specifically the piston actuation method unit 90, is configured to selectively connect the drive chambers 48 of the pump units 41, 42, 43 to the high pressure hydraulic fluid supply source 20 or tank.

The electronic control unit 70, specifically the piston actuation method unit 90, moves the pump stroke of the drive piston 47 between the pump stroke that ends and the pump stroke that begins when the pump stroke of another drive piston 47 approaches the end point. Is configured to start when there is a small overlap in. In one embodiment, the electronic control unit 70 is configured to operate each drive cylinder substantially continuously, preferably with a small overlap. Therefore, as illustrated in FIGS. 6 and 7, a substantially stable flow of LNG to the high-pressure vaporizer 14 can be realized without large pressure fluctuations.

6, 7, and 8 illustrate the normal operation of the high pressure pump 40. A thin continuous line represents the pump unit 41, a dark continuous line represents the pump unit 42, and a dotted line represents the pump unit 43. FIG. 6 is a graph showing the movement of the drive piston 46 / pump piston 62. As can be seen from the graph, the pump stroke of the next pump unit begins shortly before the end of the pump stroke of the currently operating pump unit. FIG. 7 shows the pressure obtained from the pressure outputs from the transfer pipes 50 of the three pump units 41, 42, 43. The pressure obtained is substantially constant and does not fluctuate.

FIG. 8 shows the characteristics of the speed of the pump unit. It is clearly seen here that the speed of the return stroke is significantly faster than the speed of the pump stroke, so even if only two of the three or more pump units are used, there will be overlap between the pump units. to enable.

In one embodiment, the electronic control unit 70, and more specifically the piston actuation method unit 90, ends the pump stroke in order 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 power at the time and the power at the beginning of the pump stroke.

In one embodiment, the electronic control unit 70, in particular the piston actuation method unit 90, is to determine when to start a pump stroke of one of the pump units 41, 42, 43, and the drive unit. It is configured to determine when to end any pump stroke of 41, 42, 43. Therefore, the point at which the pump stroke begins, and more specifically the point at which the pump stroke ends, can be precisely controlled by the piston actuation method unit 90, preferably together with the piston supervision unit 92.

In one embodiment, the electronic control unit 70 is such that if one of the pump units 41, 42, 43 fails, the remaining functioning drive pistons of the pump units 41, 42, 43 operate. It is composed. Therefore, redundancy is obtained, and the pumping operation can be continued even if one of the pump units 41, 42, and 43 fails.

In one embodiment, the electronic control unit 70 is a drive piston 46 in which the drive chamber 48 is disconnected from the source of high pressure hydraulic fluid in relation to the magnitude of the flow of liquefied gas from the high pressure pump 40 to the high pressure vaporizer. It is configured to adjust the position. Therefore, the position where the pump stroke reverses can be controlled regardless of the speed of the drive piston 46 and the pump piston 62 and the inertia generated.

According to one embodiment, when the flow of fuel or lubricating fluid from the high pressure pump to the engine increases, the electronic control unit 70 is located at a position where the drive chamber 48 of the associated drive piston 46 is disconnected from the high pressure fluid source 20. It is configured to adjust the position of the drive piston in the direction opposite to the drive stroke. Further, when the flow of fuel or lubricating liquid from the high-pressure pump to the engine is reduced, the electronic control unit 70 moves the drive piston 46 at a position where the drive chamber 48 of the related drive piston 46 is separated from the high-pressure liquid supply source 20. Is configured to adjust the position of the drive stroke. This is shown in FIGS. 10 and 11.

FIG. 10 shows the effect of increased speed of the drive piston 46 and pump piston 62 at the final position of the drive stroke / pump stroke. A thin continuous line represents the pump unit 41, a dark continuous line represents the pump unit 42, and a dotted line represents the pump unit 43. The electronic control unit 70 tanks the drive chamber 48 with respect to the hydraulic pressure control valve 24 when the drive piston reaches a stroke of 80 mm, regardless of the load / magnitude of the flow of liquefied gas delivered by the high pressure pump 40. Signal to connect to. Due to inertia and faster speed, the stop / reverse position of the drive piston 46 changes from 85 mm at 25 percent load to 89 mm at 50 percent load and 98 mm at 100 percent load.

FIG. 11 compensates for the increased speed of the drive piston 46 / pump piston 62 by connecting the drive chamber 48 to the tank with a shorter stroke when the load is heavy and a longer stroke when the load is light. It is a graph which shows the effect of an electronic control unit 70. As can be seen in the graph, the electronic control unit 70 can thus accurately control the final position of the drive / pump stroke.

In the example graph, the signal connecting the drive chamber 48 to the tank for a 25% load for the next drive cylinder (ie 25% of the maximum capacity of the high pressure pump 40) is that the previous cylinder is 75 mm into the drive chamber. Emitted when entering. The drive chamber of the "front" drive cylinder is connected to the tank when the cylinder enters the drive chamber 93 mm. The "signal ON" for the connection of the next drive cylinder to the high pressure source and the "signal OFF" for the connection of the "previous" cylinder to the tank are shown in Table 1 below.

Of course, it is also possible to program the electronic control unit 70 to deliberately change the starting position to reduce wear on the pump cylinder 61.

In one embodiment, the electronic control unit 70 distributes the position where the pump piston 62 reverses over the stroke region of the pump piston 62 to reduce wear on the pump cylinder 61, so that there is no algorithm, plan, or none. By action, the drive chamber 48 of the associated drive piston 46 is configured to adjust the position of the drive piston 46 that is disconnected from the high pressure liquid supply source 20. It is known that the wear of the pump cylinder 61 is most severe at the end point position of the pump stroke. By changing the end position of the pump stroke, the wear of the pump cylinder 61 can be diffused over a larger area and thus the life of the pump cylinder 61 can be significantly increased.

In one embodiment, the electronic control unit 70 is configured to control the operation and deactivation of the respective drive pistons 46 independently of the control pressure of the hydraulic fluid supplied to the drive chamber 48. Therefore, the control method for the operation of the drive piston can be optimized by the electronic control unit 70 regardless of the pressure control.

The present invention has been described with various embodiments herein. However, those skilled in the art who practice the claimed invention can understand and realize other variations of the disclosed embodiments by examining the drawings, the present disclosure, and the appended claims. In the claims, the word "provide" does not exclude other elements or steps, nor does it exclude that there may be multiple configurations that are not specified to be plural. Electronic control units can be formed by a combination of individual electronic control units. The fact that certain measurements are listed in different dependent claims does not indicate that a combination of these measurements cannot be used as an advantage. The reference code used in the claims shall not be construed as limiting the scope.

Claims (15)

A cryogenic pump (40) for pumping cryogenic fuel, comprising two or more pump units (41, 42, 43), each pump unit (41, 42, 43) being single. The pump piston (62) slidably arranged in the pump cylinder (61) of the above, and the hydraulic drive piston (46) slidably arranged in a single drive cylinder (45).
The drive piston (46) is coupled to the pump piston (62) to drive the pump piston (62).
The drive cylinder (45) includes a drive chamber (48) and a return chamber (47).
The one or more of the pump units (41, 42 ) by selectively connecting the drive chamber (48) of the relevant drive cylinder (45) to either the high pressure hydraulic fluid source (22) or the tank. , in order to control the flow of hydraulic fluid from said drive chamber (48) of the hydraulic fluid flow and the drive cylinder of the drive chamber (48) (45) of the drive cylinder (45) of 43), high pressure Further comprising at least one electronically controlled valve (24) connected to a hydraulic fluid supply source (22), a tank and a drive chamber (48) of the associated drive piston (46).
The source (22) of the high pressure hydraulic fluid is a source having a variable and controllable pressure level.
The return chamber (47) is permanently connected to the hydraulic fluid supply source (30) at a pressure lower than the pressure of the high pressure hydraulic fluid supply source (22).
The drive cylinder (45 ) is provided with a position sensor (56) for detecting the position of the drive piston (46) in the related drive cylinder (45).
An electronic control unit (70) that receives a signal from the position sensor (56) is further provided.
The electronic control unit (70) is configured to control the pressure of the high-pressure hydraulic fluid supply source (22).
The electronic control valve (24) is coupled to the electronic control unit (70).
At least one electronic control unit (70) uses the drive chamber (48) of the drive cylinder (45) of the pump unit (41, 42, 43) as a source (22) or tank of the high-pressure hydraulic fluid. Configured to selectively connect to
In the electronic control unit (70), the drive chamber (48) is the source of the high pressure hydraulic fluid ( 22) in relation to the magnitude of the flow of fuel or lubricating fluid pumped by the cryogenic pump (40). ) Is configured to adjust the position of the drive piston (46).
When the electronic control unit (70) increases the magnitude of the flow of cryogenic fuel pumped by the cryogenic pump (40), it drives the drive cylinder (45) of the drive piston (46) involved. chamber (48) by the Rukoto is configured to position, adjust the direction opposite to the direction of the drive stroke of the driving piston (46) which is decoupled from the high pressure liquid source (22), a result of the drive stroke The length is not affected by the speed of the drive stroke,
When the magnitude of the cryogenic fuel flow from the cryogenic pump (40) is reduced by the electronic control unit (70), the drive chamber (48 ) of the drive cylinder (45) of the drive piston (46) involved. ) and the position of the drive piston (46) which is decoupled from the high pressure liquid source (22), by Rukoto is configured to adjust the direction of the drive stroke, the resulting length of the drive stroke, the drive stroke Cryogenic pump (40) that does not affect the speed of. The electronic control unit (70) has a small overlap between the pump stroke of a drive piston and the pump stroke that ends and the pump stroke that begins when the pump stroke of another drive piston is approaching the end point. The ultra-low temperature pump (40) of claim 1, configured to start as is. The electronic control unit (70) takes into account the power at the end of the pump stroke and the power at the beginning of the pump stroke in order to obtain a substantially constant flow of fuel or lubricating fluid from the pump. The ultra-low temperature pump (40) according to claim 1. The ultra-low temperature pump (40) according to claim 3 , wherein the electronic control unit (70) is configured to operate each of the drive cylinders substantially continuously and with a small overlap. The electronic control unit (70) is algorithmically, planned, or randomized to distribute the position where the pump piston reverses over the stroke portion of the pump piston to reduce wear on the pump cylinder. The ultra-low temperature pump (40) according to any one of claims 1 to 4 , which is configured to adjust the position of the drive piston. Said electronic control unit (70) by controlling the pressure of hydraulic fluid supplied to said drive chamber, configured to control the pressure of the fuel or lubricating fluid leaves the pump, according to claim 1 to 5 The ultra-low temperature pump (40) according to any one. The electronic control unit (70) is configured to use the desired pressure of fuel or lubricating fluid leaving the pump in a feed forward function for controlling the pressure of the hydraulic fluid supplied to the drive piston. Item 6. The ultra-low temperature pump (40) according to Item 6. The electronic control unit (70) is configured to use the measured pressure of fuel or lubricant leaving the pump in a feedback function to control the pressure of the hydraulic fluid supplied to the drive piston. The ultra-low temperature pump (40) according to claim 6 or 7. The electronic control unit (70) is configured to control the operation and deactivation of the respective drive pistons (46) independently of the control of the pressure of the hydraulic fluid supplied to the drive chamber. The ultra-low temperature pump (40) according to any one of 1 to 8. Any of claims 1 to 9 , wherein the electronic control unit (70) is configured to use a signal representing the position of the drive piston (46) to control the actuation and deactivation of the drive piston. The ultra-low temperature pump (40) according to. A large two-stroke turbocharged compression ignition internal combustion engine comprising the cryogenic pump (40) according to any one of claims 1 to 10 for supplying fuel or lubricating fluid to the engine. A method for controlling the operation of the pump piston of a pump (40), wherein the pump (40) comprises two or more pump units (41, 42, 43), each pump unit (41, 42, 43) include a pump piston (62) slidably arranged on the pump cylinder (61) and a hydraulically driven piston (46) slidably arranged on the drive cylinder (45). , The drive piston (46) is coupled to the pump piston (62) to drive the pump piston (62).
The drive cylinder (45) includes a drive chamber (48) and a return chamber (47).
The one or more of the pump units (41, 42 ) by selectively connecting the drive chamber (48) of the relevant drive cylinder (45) to either the high pressure hydraulic fluid source (22) or the tank. , in order to control the flow of hydraulic fluid from said drive chamber (48) of the hydraulic fluid flow and the drive cylinder of the drive chamber (48) (45) of the drive cylinder (45) of 43), high pressure It comprises at least one electronically controlled valve (24) connected to the hydraulic fluid supply source (22), the tank and the drive chamber (48) of the associated drive piston (46).
The source (22) of the high pressure hydraulic fluid is a source having a variable and controllable pressure level.
The return chamber (47) is permanently connected to the hydraulic fluid supply source (30) at a pressure lower than the pressure of the high pressure hydraulic fluid supply source (22).
The method is characterized in that the drive cylinder (45) is provided with a position sensor (56) for detecting the position of the drive piston (46 ) in the related drive cylinder (45).
Activate the drive piston (46) with the electronically controlled valve (24) for the drive stroke and then deactivate the drive piston (46) with the electronically controlled valve (24) for the return stroke. To do and
Measuring the position of the drive piston (46) provided with the position sensor (56) during the drive stroke, and
Activating the drive piston (46) when the drive piston (46) is in the return position and
The drive piston (46) is deactivated at the position of the drive piston (46) in relation to the magnitude of the flow of fuel or lubricating fluid pumped by the cryogenic pump (40).
When the magnitude of the flow of cryogenic fuel pumped by the cryogenic pump (40) increases, the drive chamber (48) of the drive cylinder (45) of the drive piston (46) involved is of the high pressure liquid. the position of the drive piston is disconnected from the source (22) (46), by adjustments in the direction opposite to the drive stroke, the resulting length of the drive stroke, without affecting the speed of the drive stroke ,
When the magnitude of the flow of the cryogenic fuel from said cryogenic pump (40) is reduced, the drive chamber (48) is the source of high pressure fluid of the drive cylinder of the driving piston of interest (46) (45) ( the position of the drive piston (46) to be disconnected from the 22), by adjustments in the direction of the drive stroke, the resulting length of the drive stroke, does not affect the speed of the drive stroke, the method. Said drive piston (46), so that the next drive piston just before the drive piston is currently actuation (46) stops operation (46) is actuated, are operated substantially continuously, according to claim 12, wherein the method of. A high-pressure hydraulic fluid is supplied to the drive piston (46) to supply the drive piston (46).
12. The method of claim 12 or 13 , wherein the pressure of the fuel or lubricating fluid leaving the pump (40) is controlled by controlling the pressure of the hydraulic fluid supplied to the drive piston (46). Said drive piston (46), so that the next drive piston just before the drive piston is currently actuation (46) stops operation (46) is actuated, it is operated substantially continuously, claims 12 to 14. The method according to any one of 14.

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