JP2016200140A - Fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supply device capable of reducing pulsation of pressure of fuel caused by a reciprocating pump.SOLUTION: A fuel supply device for supplying fuel into a combustion chamber of an internal combustion engine comprises: a low-pressure fuel supply pipe through which low-pressure fuel is supplied; a high-pressure fuel supply pipe through which high-pressure fuel to be supplied into the combustion chamber is supplied; a plurality of fuel supply units provided between the low-pressure fuel supply pipe and the high-pressure fuel supply pipe for pressurizing the fuel within the low-pressure fuel supply pipe and each supplying the fuel to the high-pressure fuel supply pipe; and a control unit for controlling the plurality of fuel supply units. The control unit controls the plurality of fuel supply units such that the sum of the discharge amounts per unit time of the fuel discharged from each of the plurality of fuel supply units approaches a constant value.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a fuel supply device that supplies fuel to an internal combustion engine such as a diesel engine.

2. Description of the Related Art Conventional marine vessels use a two-stroke cycle low-speed diesel engine that can output at low speed and can be driven directly by a propeller.
In recent years, natural gas with low NO _x and SO _x emissions has attracted attention as a fuel for low-speed diesel engines. By injecting and burning high-pressure natural gas as fuel in the combustion chamber of a low-speed diesel engine, output can be obtained with high thermal efficiency.

  For example, a reciprocating pump is driven by changing a rotary motion to a reciprocating motion using a crankshaft. When the piston of the reciprocating pump is driven using the crankshaft, the piston stroke is determined by the crankshaft, so that the piston stroke cannot be freely adjusted. Further, when a plurality of reciprocating pumps are driven by the same crankshaft, each of the reciprocating pumps cannot be controlled independently.

  On the other hand, Patent Document 1 describes an apparatus for increasing the pressure of liquid fuel using a reciprocating pump and supplying it to an engine. In the device of Patent Document 1, a piston of a reciprocating pump is driven in the left-right direction, and a “linear hydraulic motor” (hydraulic cylinder unit) is used as a linear actuator for driving the piston. In Patent Document 1, the moving direction of the piston of the reciprocating pump is switched by switching the direction of hydraulic oil supplied from the hydraulic pump to the hydraulic cylinder unit with a direction switching valve. When the hydraulic cylinder unit is used, the reciprocating pump can be driven at a lower speed than when the crankshaft is used. Further, there is an advantage that the piston stroke can be controlled so that the piston moves at a constant speed.

JP 2005-504927 A

By the way, in a fuel supply apparatus that supplies fuel to an internal combustion engine using a reciprocating pump, there are various causes of pulsation, but there is a problem that pulsation occurs due to the timing at which fuel is discharged from the reciprocating pump.
FIGS. 11A, 11B, and 11C are diagrams illustrating examples of changes over time in the discharge amount of each reciprocating pump when three reciprocating pumps are driven using a crankshaft. 11 (d) is a diagram showing a change over time of the total discharge amount of (a), (b), and (c). Since the rotational movement of the crankshaft is converted into the linear movement of the piston, each piston moves in a sine wave shape, and the time change of the discharge amount of each reciprocating pump also becomes a sine wave shape. By shifting the discharge timing by the three reciprocating pumps by 1/3 period, as shown in FIG. 11 (d), the total time change of the discharge amount is reduced, but the time change disappears completely. There was no cause of pulsation. When the rotational speed is reduced, the amplitude of the waveform of the discharge amount gradually decreases, but the total time change of the discharge amount does not disappear completely.
Patent Document 1 describes that the generation of pressure pulses is reduced by controlling the piston stroke so that the piston moves at a constant speed. However, the apparatus of Patent Document 1 has a problem in that the pulsation corresponding to the reciprocating cycle of the piston occurs because the pressure increases at the downstream side of the reciprocating pump as compared with the time of suction when the fuel is discharged.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel supply device that can reduce fuel pressure pulsation caused by a reciprocating pump.

  A first aspect of the present invention is a fuel supply device that supplies fuel into a combustion chamber of an internal combustion engine, wherein a low-pressure fuel supply pipe that is supplied with low-pressure fuel, and a high-pressure fuel that is supplied into the combustion chamber. A plurality of fuels provided between the high-pressure fuel supply pipe to be supplied, the low-pressure fuel supply pipe, and the high-pressure fuel supply pipe, and pressurize the fuel in the low-pressure fuel supply pipe and supply the fuel to the high-pressure fuel supply pipe, respectively. A supply unit; and a control unit that controls the plurality of fuel supply units, wherein the control unit has a constant sum of discharge amounts per unit time of fuel discharged from each of the plurality of fuel supply units. The plurality of fuel supply units are controlled so that

  The control unit controls the plurality of fuel supply units such that when the discharge amount of fuel from at least one fuel supply unit increases, the discharge amount of fuel from other fuel supply units decreases. Is preferred.

  The control unit includes the plurality of fuel supply units such that the sum of the increase amounts in the fuel supply unit where the fuel discharge amount increases matches the sum of the decrease amounts of the fuel discharge amounts from the other fuel supply units. Is preferably controlled.

  Each of the fuel supply units has a linear actuator and a boosting piston driven by the linear actuator and reciprocating in the axial direction, and the fuel is supplied when the boosting piston moves in the first axial direction. A reciprocating pump that inhales and boosts and discharges the fuel when the boosting piston moves in the second axial direction; and a controller that is controlled by the control unit and controls the driving of the linear actuator; It is preferable to provide.

  As the linear actuator, for example, a hydraulic cylinder unit, having a hydraulic oil storage space for storing hydraulic oil, the hydraulic cylinder arranged so that the axial direction coincides with the axial direction of the boosting piston, A hydraulic piston which is provided so as to be movable in the axial direction within the hydraulic cylinder, and divides the hydraulic oil storage space into a first chamber and a second chamber; and a piston rod which connects the hydraulic piston and the boosting piston; Supplying the hydraulic oil to the first chamber moves the hydraulic piston in the first axial direction, and supplying the hydraulic oil to the second chamber causes the hydraulic piston to move in the second axial direction. And a hydraulic pump that moves the hydraulic pump and an electric motor that drives the hydraulic pump so that the hydraulic piston reciprocates in the axial direction. That. In this case, the controller controls the movement of the hydraulic piston in the hydraulic cylinder by controlling the electric motor.

The hydraulic cylinder unit has one end connected to the hydraulic pump and the other end connected to the first chamber. The hydraulic cylinder unit supplies all the hydraulic oil discharged from the hydraulic pump to the first chamber. A closed first hydraulic pipe that returns all the hydraulic oil discharged from the hydraulic pump to the hydraulic pump, one end connected to the hydraulic pump, the other end connected to the second chamber, and discharged from the hydraulic pump It is preferable to further include a sealed second hydraulic pipe for supplying all the hydraulic oil to the second chamber and returning all the hydraulic oil discharged from the second chamber to the hydraulic pump.
The linear actuator may be an electric cylinder unit.
The electric cylinder unit is connected to the boosting piston in a state in which the electric motor, a ball nut rotated by the power of the electric motor, and the ball nut are screwed and the axial direction coincides with the axial direction of the boosting piston. And a ball screw that moves in the axial direction by rotation of the ball nut, and the controller preferably controls movement of the ball screw in the axial direction by controlling the electric motor.

  According to the present invention, by controlling the plurality of fuel supply units so that the sum of the discharge amounts per unit time of the fuel discharged from each of the plurality of fuel supply units approaches a constant value, The pulsation of the fuel pressure can be reduced.

It is a schematic block diagram of the fuel gas supply apparatus of this embodiment. 2 is a cross-sectional view of the linear actuator 30 and the reciprocating pump 50 during fuel suction. FIG. 2 is a cross-sectional view of the linear actuator 30 and the reciprocating pump 50 when fuel is discharged. FIG. (A) is an example of time change of the discharge amount of the fuel supply unit 20A, (b) is an example of time change of the discharge amount of the fuel supply unit 20B, and (c) is an example of time change of the discharge amount of the fuel supply unit 20C. (D) is a figure which shows an example of the time change of the sum total of each discharge amount of fuel supply part 20A, 20B, 20C. (A) is an example of the time change of the discharge amount of the fuel supply unit 20A, (b) is an example of the time change of the discharge amount of the fuel supply unit 20B, and (c) is the fuel supply unit 20A of (a) and (b). 20B is a diagram illustrating an example of a temporal change in the total discharge amount of 20B. (A) is an example of time change of the discharge amount of the fuel supply unit 20A, (b) is an example of time change of the discharge amount of the fuel supply unit 20B, and (c) is an example of time change of the discharge amount of the fuel supply unit 20C. , (D) is an example of the time change of the discharge amount of the fuel supply unit 20D, (e) is the time change of the total discharge amount of the fuel supply units 20A, 20B, 20C, 20D of (a) to (d). It is a figure which shows an example. (A) is an example of time change of the discharge amount of the fuel supply unit 20A, (b) is an example of time change of the discharge amount of the fuel supply unit 20B, and (c) is an example of time change of the discharge amount of the fuel supply unit 20C. (D) is a figure which shows an example of the time change of the sum total of each discharge amount of fuel supply part 20A, 20B, 20C of (a)-(c). (A) is another example of time change of the discharge amount of the fuel supply unit 20A, (b) is another example of time change of the discharge amount of the fuel supply unit 20B, and (c) is a discharge amount of the fuel supply unit 20C. FIG. 6D is a diagram showing another example of the time change of the total discharge amount of each of the fuel supply units 20A, 20B, and 20C. (A) is another example of time change of the discharge amount of the fuel supply unit 20A, (b) is another example of time change of the discharge amount of the fuel supply unit 20B, and (c) is a discharge amount of the fuel supply unit 20C. FIG. 6D is a diagram showing another example of the time change of the total discharge amount of each of the fuel supply units 20A, 20B, and 20C. 2 is a view showing a fuel supply unit using an electric cylinder unit as a linear actuator 30. FIG. (A), (b), (c) is a figure which shows the example of the time change of the discharge amount of each reciprocating pump when driving three reciprocating pumps using a crankshaft, (d) These are figures which show the time change of the total of the discharge amount of (a), (b), (c).

Hereinafter, a fuel supply device according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the fuel supply device 10 of the present embodiment is a device that pressurizes and heats liquid fuel and injects it into the combustion chamber of the internal combustion engine 90 at a high pressure. The internal combustion engine 90 is a prime mover that burns fuel in a combustion chamber in a cylinder and works by its thermal energy, such as a reciprocating engine or a gas turbine. In particular, a diesel engine that compresses and ignites fuel is preferably used as the internal combustion engine 90. In the following embodiment, a case where a diesel engine mounted on a ship is used as the internal combustion engine 90 will be described. However, the present invention can also be applied to a fuel supply apparatus for a diesel engine other than a ship.

  As shown in FIG. 1, the fuel supply apparatus 10 includes a liquid fuel tank 11, a low-pressure fuel supply pipe 12, a plurality of fuel supply units 20A, 20B, and 20C, a high-pressure fuel supply pipe 13, and a heat exchanger 14. The high-temperature fuel supply pipe 15, the pressure regulating valve 16, the pressure gauge 17, and the control unit 80 are provided. All these components of the fuel supply device 10 are mounted on a ship.

The liquid fuel tank 11 stores the fuel supplied to the internal combustion engine 90 in a liquid state. As the liquid fuel stored in the liquid fuel tank 11, for example, liquefied methane, liquefied ethane, liquefied propane, or the like can be used. The liquid fuel tank 11 is connected to the low-pressure fuel supply pipe 12 and supplies the liquid fuel to the fuel supply units 20A, 20B, and 20C via the low-pressure fuel supply pipe 12.
The pressure of the liquid fuel in the low-pressure fuel supply pipe 12 at the connection with the fuel supply units 20A, 20B, and 20C is a pressure corresponding to the liquid level of the liquid fuel in the liquid fuel tank 11. In order to increase the pressure and secure an effective suction head (NPSH) and to facilitate supply to the fuel supply units 20A, 20B, and 20C, the liquid fuel tank 11 is provided by the fuel supply units 20A, 20B, and 20C. Is also placed at a high position.
When the liquid fuel tank 11 cannot be disposed at a high position, an effective suction head is secured by increasing the pressure of the liquid fuel in the liquid fuel tank 11 by a booster pump that supplies the liquid fuel to the liquid fuel tank 11. Also good.

The fuel supply units 20 </ b> A, 20 </ b> B, and 20 </ b> C are provided in parallel between the low pressure fuel supply pipe 12 and the high pressure fuel supply pipe 13. Each of the fuel supply units 20A, 20B, and 20C includes a controller 21, a linear actuator 30, and a reciprocating pump 50.
The reciprocating pump 50 pressurizes the liquid fuel supplied from the low pressure fuel supply pipe 12 and supplies it to the heat exchanger 14 through the high pressure fuel supply pipe 13. The low-pressure fuel pipe 12 and the high-pressure fuel supply pipe 13 are detachable from the fuel supply units 20A, 20B, and 20C.

The linear actuator 30 drives the piston of the reciprocating pump 50. By using the linear actuator 30, the piston of the reciprocating pump 50 is driven at a lower speed than in the case of using the crankshaft. The drive can be controlled so that the piston moves at a constant speed. As the linear actuator 30, for example, a hydraulic cylinder unit, an electric cylinder unit, or the like can be used. In the present embodiment, a case where a hydraulic cylinder unit is used as the linear actuator 30 will be described.
The controller 21 is controlled by a control signal input from the control unit 80 and controls the linear actuator 30. The controller 21 receives a position signal indicating the position of the piston of the reciprocating pump 50, as will be described later. The controller 21 controls the position of the linear actuator 30 so that the discharge amount of the reciprocating pump 50 is adjusted according to the position signal.

  In FIG. 1, three fuel supply units 20A, 20B, and 20C are provided in parallel between the low pressure fuel supply pipe 12 and the high pressure fuel supply pipe 13, but the number of fuel supply parts is not limited thereto. However, it can be arbitrarily changed according to the amount of fuel to be supplied.

  The heat exchanger 14 has an inlet side connected to the high-pressure fuel supply pipe 13 and an outlet side connected to the high-temperature fuel supply pipe 15. The heat exchanger 14 heats the pressurized liquid fuel supplied through the high-pressure fuel supply pipe 13. As a heat source for heating the liquid fuel, for example, combustion heat of boil-off gas generated in the liquid fuel tank 11 can be used. For example, the liquid fuel may be heated by heat exchange with warm water heated by the combustion heat of boil-off gas.

The high temperature fuel supply pipe 15 is provided with a pressure regulating valve 16, and one end of the high temperature fuel supply pipe 15 is connected to the heat exchanger 14 and the other end is connected to the combustion chamber of the internal combustion engine 90. The liquid fuel heated by the heat exchanger 14 is regulated to a pressure within a predetermined range required by the internal combustion engine 90 by the pressure regulating valve 16, and then is supplied to the combustion chamber of the internal combustion engine 90 through the high temperature fuel supply pipe 15. Supplied. The pressure regulating valve 16 is controlled by the control unit 80.
Here, the pressure in a predetermined range required by the internal combustion engine 90 varies depending on the type and performance of the internal combustion engine 90. If the internal combustion engine 90 is a two-stroke cycle low-speed diesel engine for ships, the pressure in the predetermined range is, for example, 5 to 100 MPa, preferably 20 to 70 MPa, but the present invention is not limited to this. .
The high temperature fuel supply pipe 15 is provided with a pressure gauge 17. The pressure gauge 17 measures the pressure in the high temperature fuel supply pipe 15 and outputs a measurement signal to the control unit 80.

A signal indicating the load on the internal combustion engine 90 is input from the internal combustion engine 90 to the control unit 80. The signal indicating the load of the internal combustion engine 90 is a signal indicating the rotational speed, for example.
The control unit 80 adjusts the discharge amount of the reciprocating pump 50 by outputting a control signal to the fuel supply units 20A, 20B, and 20C. The discharge amount of the reciprocating pump 50 is adjusted so that the pressure in the high-temperature fuel supply pipe 15 becomes a pressure corresponding to the required load of the internal combustion engine 90.
Note that the number of revolutions of a propulsion propeller (not shown) driven by the internal combustion engine 90 may be measured, and the pressure in the high-temperature fuel supply pipe 15 may be adjusted according to the number of revolutions.

  The liquid fuel tank 11, the low-pressure fuel supply pipe 12, the linear actuator 30, the reciprocating pump 50, the high-pressure fuel supply pipe 13, the heat exchanger 14, the high-temperature fuel supply pipe 15, the pressure regulating valve 16, and the pressure gauge 17 are arranged in the hazardous area. Is done. On the other hand, the controller 21 and the control unit 80 are generally non-explosion-proof compatible products. However, when the explosion-proof response is not possible, the controller 21 and the control unit 80 are disposed in the non-hazardous area separated from the dangerous area by the explosion-proof partition wall, or are sufficient from the dangerous area. Must be located in a non-explosion-proof area at a distance from each other.

Next, specific configurations of the linear actuator 30 and the reciprocating pump 50 using a servo motor as an electric motor will be described in detail with reference to FIGS. In the following description, a case where a hydraulic cylinder unit is used as the linear actuator 30 will be described. However, the linear actuator 30 is not limited to the hydraulic cylinder unit.
2 and 3, the vertical direction coincides with the vertical direction, and the horizontal direction coincides with the horizontal direction. In the following description, the upward direction in the vertical direction is referred to as “upper”, the upper portion is referred to as “upper”, the lower portion in the vertical direction is referred to as “lower”, and the lower portion is referred to as “lower”. In the following description, the linear actuator 30 and the reciprocating pump 50 arranged so that the axial direction is the vertical direction will be described. However, the present invention is not limited to this, and the case where the axial direction is the horizontal direction and the angle Alternatively, the linear actuator 30 and the reciprocating pump 50 arranged so as to be in the direction in which they are provided may be used.

  In the present embodiment, the linear actuator 30 and the reciprocating pump 50 are arranged with the axial direction oriented in the vertical direction. 2 and 3, an example in which the reciprocating pump 50 is disposed below the linear actuator 30 will be described. However, the reciprocating pump 50 may be disposed above the linear actuator 30.

[Hydraulic cylinder unit]
2 and 3, the hydraulic cylinder unit (linear actuator 30) includes an electric motor 31, a hydraulic pump 32, a first hydraulic pipe 33, a second hydraulic pipe 34, a fixed portion 40, a hydraulic cylinder 41, A hydraulic piston 42 is provided.
The hydraulic cylinder unit is provided on the top plate 101 of the gantry 100. The top plate 101 is supported by legs 102, and the legs 102 are fixed to a structure such as a ship deck or an inner bottom plate.

  The electric motor 31 is provided on the top plate 101. The electric motor 31 is controlled by the controller 21 and drives the hydraulic pump 23. As the electric motor 31, for example, an inverter motor or a servo motor is used.

  The hydraulic pump 32 is provided on the top plate 101. The hydraulic pump 32 is driven by the electric motor 31 and supplies hydraulic oil into the hydraulic cylinder 41 to move the hydraulic piston 42 in the vertical direction. As the hydraulic oil, any hydraulic oil can be employed from petroleum hydraulic oil, synthetic hydraulic oil, water-forming hydraulic oil and the like.

The hydraulic pump 32 is connected to the first hydraulic pipe 33 and the second hydraulic pipe 34. The hydraulic pump 32 is driven by an electric motor 31.
When the electric motor 31 is a servo motor, the direction in which the hydraulic oil is discharged from the hydraulic pump 32 is switched according to the forward and reverse rotation directions of the electric motor 31. For example, when the electric motor 31 rotates in the forward direction, the hydraulic pump 32 sucks the hydraulic oil in the first hydraulic pipe 33 and discharges the sucked hydraulic oil to the second hydraulic pipe 34 side. When the electric motor 31 rotates in the reverse direction, the hydraulic pump 32 sucks the hydraulic oil in the second hydraulic pipe 34 and discharges the sucked hydraulic oil to the first hydraulic pipe 33 side. In this case, a direction switching valve is not necessary for the first hydraulic pipe 33 and the second hydraulic pipe 34.
On the other hand, when the electric motor 31 is an inverter motor, the direction in which the hydraulic oil flows is changed by a direction switching valve (not shown) provided in the first hydraulic pipe 33 and the second hydraulic pipe 34.
Note that the flow rate and pressure of the hydraulic oil in the first hydraulic pipe 33 and the second hydraulic pipe 34 are determined by the discharge amount of the hydraulic pump 32. In both cases where the electric motor 31 is a servo motor and the electric motor 31 is an inverter motor, the flow rate and pressure of hydraulic oil can be adjusted by the electric motor 31.

  The fixing portion 40 is fixed to the top plate 101 in a state of being disposed in an opening 101 a provided in the top plate 101. A hydraulic cylinder 41 is fixed to the upper part of the fixed part 40, and a reciprocating pump 50 is fixed to the lower part of the fixed part 40. The fixed part 40 has a hollow cylindrical shape, and a cavity part 48 is provided inside.

  The hydraulic cylinder 41 has a hydraulic oil storage space 43 for storing hydraulic oil, and is placed on the top surface of the top plate 101 so that the axial direction is the vertical direction. Further, an upper through hole 44 that communicates with the upper end portion of the hydraulic oil storage space 43 and a lower through hole 45 that communicates with the lower end portion of the hydraulic oil storage space 43 are provided on the side wall of the hydraulic cylinder 41. The outer opening of the upper through hole 44 is connected to the first hydraulic pipe 33, and the outer opening of the lower through hole 45 is connected to the second hydraulic pipe 34.

  The hydraulic piston 42 is provided with a piston ring 42b. The hydraulic piston 42 has a piston ring 42b in contact with the inner wall surface of the hydraulic oil storage space 43 of the hydraulic cylinder 41, and the rider ring 42a accommodated in the hydraulic oil storage space 43 is movable in the vertical direction. It plays a role of correcting horizontal shake when moving in the vertical direction. The piston ring 42 b serves to close the gap between the hydraulic piston 42 and the inner wall surface of the hydraulic oil storage space 43.

The hydraulic piston 42 divides the hydraulic oil containing space 43 into an upper chamber 43 a above the hydraulic piston 42 and a lower chamber 43 b below the hydraulic piston 42.
The hydraulic piston 42 is a double rod type, and has a piston rod 47 that protrudes from the upper and lower portions of the hydraulic cylinder 41 to the outside. The piston rod 47 moves up and down together with the hydraulic piston 42. Since the hydraulic piston 42 is a double rod type, the amount of decrease in the volume of the upper chamber 43a when the hydraulic piston 42 is raised is equal to the amount of increase in the volume of the lower chamber 43b. The hydraulic piston 42 may be a single rod type. However, in this case, it is desirable to provide a pulsation prevention tank because pressure fluctuations occur due to changes in the amount of moving hydraulic oil.
A bush 46 is provided in a portion of the hydraulic cylinder 41 through which the piston rod 47 passes. An oil seal is incorporated in the bush 46. The bush 46 supports the piston rod 47 so as to be movable up and down, and prevents hydraulic oil from leaking from the hydraulic oil storage space 43.

  In the cavity 48, a connecting portion 49 that connects the lower end portion of the piston rod 47 and the upper end portion of the boosting piston 52 of the reciprocating pump 50 is provided. The connecting portion 49 moves up and down in the cavity 48 as the piston rod 47 moves up and down. The connecting portion 49 has a function of adjusting the axial misalignment between the piston rod 47 of the hydraulic cylinder and the piston 52 of the reciprocating pump 50.

  From the viewpoint of preventing gas leakage from the reciprocating pump, room temperature nitrogen gas is supplied to the cavity 48 from the outside. Nitrogen gas may be supplied to the rod packing portion 57 of the reciprocating pump 50. By providing the cavity 48, heat conduction to the low-temperature heat source (liquid fuel) in the reciprocating pump 50 is suppressed, and the high-temperature heat source (hydraulic oil) in the hydraulic oil storage space 43 is cooled via the piston rod 47. Can be prevented. In addition, you may prevent that a high temperature heat source is cooled by providing an explosion-proof heater and a heat sink.

[Reciprocating pump]
As the reciprocating pump 50, for example, a reciprocating pump having the same structure as that described in Japanese Patent No. 5519857 can be used.
Specifically, the reciprocating pump 50 includes a boosting cylinder 51, a boosting piston 52, a cylinder liner 53, a cover 54, a valve box 60, and the like.

The upper end portion of the boosting cylinder 51 is fixed to the lower end portion of the fixing portion 40. The side wall of the boosting cylinder 51 is fixed to the legs 102 of the gantry 100. A rod packing portion 57 is provided on the upper portion of the boosting cylinder 51.
The boosting cylinder 51 has a space for accommodating the boosting piston 52, the cylinder liner 53, and the valve box 60 inside, and a cover 54 is fixed to the lower end portion of the boosting cylinder 51. The cylinder liner 53 and the valve box 60 are fixed in the boosting cylinder 51 by the cover 54.
Further, a suction port 55 is provided on the side wall of the boosting cylinder 51 at a height position where the valve box 60 is fixed. The suction port 55 is connected to the low pressure fuel supply pipe 12.
The cover 54 is provided with a discharge port 56 penetrating in the vertical direction. The discharge port 56 is connected to the high-pressure fuel supply pipe 13.

  Here, the valve box 60 is provided below the boosting piston 52, and when the boosting piston 52 is moved vertically upward, the fuel is placed inside the boosting cylinder 51 and below the boosting piston 52. For suctioning, the suction port 55 of the reciprocating pump 50 can be arranged at a lower position. The pressure of the liquid fuel in the low-pressure fuel supply pipe 12 at the connection portion with the suction port 55 is a pressure proportional to the difference between the height of the liquid fuel level in the liquid fuel tank 11 and the height of the suction port 55. For this reason, the pressure of the liquid fuel in the low-pressure fuel supply pipe 12 at the connection portion with the suction port 55 can be increased by arranging the suction port 55 at a lower position. As a result, fuel can be easily supplied from the suction port 55 into the pressure-increasing cylinder 51.

The upper end of the boosting piston 52 is connected to the lower end of the piston rod 47 by a connecting portion 49, and the boosting piston 52 moves up and down in conjunction with the piston rod 47.
A position sensor is provided at the upper end of the boosting piston 52. The position sensor detects the position of the boosting piston 52 in the vertical direction and outputs a position signal to the controller 21. Note that the speed of the boosting piston 52 can be obtained by differentiating the displacement of the boosting piston 52 with time using the position signal. That is, the position sensor can also be used as a speed sensor.
A position sensor may be attached to the hydraulic cylinder 41.

As the position sensor, for example, a magnetostrictive position sensor 70 or an ultrasonic sensor can be used. Here, a case where a magnetostrictive position sensor is used will be described.
Specifically, the magnetostrictive position sensor 70 includes a sensor probe 71 (magnetostrictive line), an annular magnet 72, and a detector 73. The sensor probe 71 is provided in the cavity 48 in the vertical direction. The annular magnet 72 is attached to the upper end of the boosting piston 52 so as to move up and down along with the boosting piston 52 along the sensor probe 71 with the sensor probe 71 inserted in the center. One end of the sensor probe 71 is provided with a detector 73 that detects distortion generated in the sensor probe 71. When a current pulse signal is applied to the sensor probe 71, a magnetic field in the circumferential direction around the sensor probe 71 is generated. At a position at the same height as the magnet 72 of the sensor probe 71, a magnetic field is applied in the axial direction of the sensor probe 71, so that a combined magnetic field oblique to the axial direction is generated. This causes local torsional distortion in the sensor probe 71. The detector 73 detects the torsional distortion to detect the position of the magnet 72 in the height direction, and outputs a position signal indicating the position of the boosting piston 52 in the height direction to the controller 21.

  A rider ring 52 a and a piston ring 52 b are provided below the boosting piston 52. The boosting piston 52 is accommodated in the cylinder liner 53 so as to be movable in the vertical direction while bringing the rider ring 52a and the piston ring 52b into contact with the inner wall surface of the cylinder liner 53. The rod packing portion 57 is also equipped with a rider ring 51a. These rider rings 51a and 52a play a role of correcting horizontal shake when the boosting piston 52 moves in the vertical direction. The piston ring 52b serves to close the gap between the boosting piston 52 and the inner wall surface of the cylinder liner 53 and seal the pressure of the pressurized liquid fuel at the tip.

The valve box 60 is fixed to the lower portion of the cylinder liner 53 in the boosting cylinder 51. The valve box 60 is provided with a discharge flow path 61, a discharge valve body 62, a suction flow path 64, a suction valve body 65, and the like.
The discharge flow path 61 is provided so as to penetrate the valve box 60 in the vertical direction. A discharge valve element 62 is accommodated in the discharge flow path 61 so as to be movable in the vertical direction. The upper end portion side of the discharge channel 61 is a small diameter portion whose inner diameter is smaller than the outer diameter of the discharge valve body 62. The lower opening of the narrow diameter portion is a valve seat 63 in which the discharge valve body 62 is disposed. The discharge valve element 62 and the valve seat 63 constitute a discharge valve.
An opening on the lower side of the valve box 60 of the discharge channel 61 is provided at a position facing the discharge port 56 of the cover 54.

The suction flow path 64 is provided at a position communicating with the position of the boosting piston 52 on the upper surface of the valve box 60 from the outer wall of the valve box 60. The opening on the outer wall side of the valve box 60 of the suction flow path 64 is provided at a position facing the suction port 55 of the boosting cylinder 51.
The outer peripheral portion of the opening on the upper surface side of the valve box 60 of the suction flow path 64 is a valve seat 66 for the suction valve body 65, and the suction valve body 65 can move in the vertical direction above the valve seat 66. Is provided. The suction valve element 65 and the valve seat 66 constitute a suction valve.

  The rod packing portion 57 is connected to the cavity portion 48 and is equipped with a seal ring for sealing so that the gas vaporized by the liquid fuel does not leak to the outside air. The leaked liquid fuel that cannot be sealed by the piston ring 52 b is vaporized under a low pressure and is sealed by the rod packing portion 57. In order to prevent leakage of gas vaporized by the liquid fuel to the outside, nitrogen gas may be supplied to the rod packing portion 57 instead of supplying it to the cavity portion 48.

[Operation of linear actuator and reciprocating pump]
Next, operations of the linear actuator 30 and the reciprocating pump 50 using a servo motor as the electric motor will be described.
First, the hydraulic pump 32 is driven by the electric motor 31, and as shown in FIG. 2, the hydraulic oil in the upper chamber 43a is discharged from the upper through hole 44, and the first hydraulic pipe 33 and the second hydraulic pipe 34 are connected. Then, the gas is supplied from the lower through hole 45 to the lower chamber 43b. Then, the hydraulic piston 42 rises in the hydraulic oil storage space 43 so that the volume of the lower chamber 43b increases and the volume of the upper chamber 43a decreases. Since the first hydraulic pipe 33 and the second hydraulic pipe do not have a branch or the like, all the hydraulic fluid that has flowed out of the upper chamber 43a is supplied to the lower chamber 43b.

  When the hydraulic piston 42 rises, the boosting piston 52 connected to the lower end of the piston rod 47 at the connecting portion 49 rises in the cylinder liner 53. Then, the suction valve body 65 is lifted away from the valve seat 66, and the liquid fuel supplied from the suction port 55 passes through the suction flow path 64 and is inside the cylinder liner 53 and below the boosting piston 52. Flow into. At this time, the discharge valve body 62 is in a state of closing the valve seat 63.

  Next, the rotation direction of the electric motor 31 is switched by the controller 21 and the hydraulic pump 32 is driven in the direction opposite to that in FIG. 2, and as shown in FIG. And is supplied from the upper through hole 44 to the upper chamber 43a through the second hydraulic pipe 34 and the first hydraulic pipe 33. Then, the hydraulic piston 42 descends in the hydraulic oil storage space 43 so that the volume of the lower chamber 43b decreases and the volume of the upper chamber 43a increases. Since the first hydraulic pipe 33 and the second hydraulic pipe do not have a branch or the like, all the hydraulic oil flowing out from the lower chamber 43b is supplied to the upper chamber 43a.

  When the hydraulic piston 42 is lowered, the boosting piston 52 connected to the lower end portion of the piston rod 47 at the connecting portion 49 is lowered in the cylinder liner 53. Then, the liquid fuel sucked into the space inside the cylinder liner 53 and below the boosting piston 52 pushes down the discharge valve body 62 to be separated from the valve seat 63 and passes through the suction passage 64 and from the discharge port 56. Discharged. Inflow. At this time, the suction valve body 65 is in a state of closing the valve seat 66.

In this way, by switching the rotation direction of the electric motor 31 and switching the driving direction of the hydraulic pump 32, the hydraulic oil is alternately passed between the upper chamber 43a and the lower chamber 43b, and the hydraulic piston 42 and the booster pump are increased. The piston 52 can be reciprocated in the vertical direction, and the liquid fuel sucked from the suction port 55 can be pressurized and discharged from the discharge port 56.
In the case of the linear actuator 30 that uses an inverter motor for the electric motor, the hydraulic oil is alternately moved between the upper chamber 43a and the lower chamber 43b by switching the flow direction of the hydraulic oil by the direction switching valve. The hydraulic piston 42 and the boosting piston 52 are reciprocated in the vertical direction, and the liquid fuel sucked from the suction port 55 can be boosted and discharged from the discharge port 56.

  In the present embodiment, the control unit 80 controls the fuel supply units 20A, 20B, and 20C so that the total amount of fuel discharged from the boost cylinders 51 of the fuel supply units 20A, 20B, and 20C is constant. The respective controllers 21 are preferably controlled.

  Specifically, when the amount of fuel discharged from at least one of the fuel supply units 20A, 20B, and 20C increases, the control unit 90 is configured so that the amount of fuel discharged from the other fuel supply units decreases. What is necessary is just to control several fuel supply part 20A, 20B, 20C.

For example, among the plurality of fuel supply units 20A, 20B, and 20C, the total increase amount in the fuel supply unit that increases the fuel discharge amount matches the total decrease amount of the fuel discharge amount from the other fuel supply units. Thus, the control unit 90 may control the plurality of fuel supply units 20A, 20B, and 20C.
The discharge amount of each of the fuel supply units 20A, 20B, and 20C is the product of the cross-sectional area and speed of the boosting piston 52. Therefore, the controller 21 controls the linear actuator 30 to adjust the speed of the boosting piston 52, that is, to adjust the oil pressure by adjusting the amount of oil flowing into the hydraulic cylinder 41, thereby supplying fuel. Each discharge amount of the sections 20A, 20B, and 20C can be adjusted.

  4A is a diagram illustrating an example of a change over time in the discharge amount of the fuel supply unit 20A, and FIG. 4B is a diagram illustrating an example of a change over time in the discharge amount of the fuel supply unit 20B. (C) is a figure which shows an example of the time change of the discharge amount of 20 C of fuel supply parts, FIG.4 (d) is each discharge of fuel supply part 20A, 20B, 20C of Fig.4 (a)-(c). It is a figure which shows an example of the time change of the total of quantity.

From time t0 to t1, the discharge amount of the fuel supply unit 20A increases as shown in FIG. 4A, and at the same time, the discharge amount of the fuel supply unit 20C decreases as shown in FIG. 4C. As shown in FIG. 4B, the discharge amount of the fuel supply unit 20B is zero. At this time, since the increase amount of the discharge amount of the fuel supply unit 20A is equal to the decrease amount of the discharge amount of the fuel supply unit 20C, the total discharge amount is constant as shown in FIG.
From time t1 to t2, since the discharge amount of the fuel supply unit 20A is constant and the discharge amounts of the other fuel supply units 20B and 20C are zero, as shown in FIG. Is constant.

From time t2 to t3, as shown in FIG. 4B, the discharge amount of the fuel supply unit 20B increases, and at the same time, the discharge amount of the fuel supply unit 20A decreases as shown in FIG. 4A. As shown in FIG. 4C, the discharge amount of the fuel supply unit 20C is zero. At this time, since the increase amount of the discharge amount of the fuel supply unit 20B is equal to the decrease amount of the discharge amount of the fuel supply unit 20A, the total discharge amount is constant as shown in FIG.
From time t3 to t4, the discharge amount of the fuel supply unit 20B is constant, and the discharge amounts of the other fuel supply units 20A and 20C are zero. Therefore, as shown in FIG. Is constant.

From time t4 to t5, as shown in FIG. 4C, the discharge amount of the fuel supply unit 20C increases, and at the same time, the discharge amount of the fuel supply unit 20B decreases as shown in FIG. 4B. As shown in FIG. 4A, the discharge amount of the fuel supply unit 20A is zero. At this time, since the increase amount of the discharge amount of the fuel supply unit 20C is equal to the decrease amount of the discharge amount of the fuel supply unit 20B, the total discharge amount is constant as shown in FIG.
From time t5 to t6, the discharge amount of the fuel supply unit 20C is constant, and the discharge amounts of the other fuel supply units 20A and 20B are zero. Therefore, as shown in FIG. Is constant.

  As described above, the control unit 80 controls each of the fuel supply units 20A, 20B, and 20C so that the sum of the discharge amounts of the fuel discharged from the boost cylinders 51 of the fuel supply units 20A, 20B, and 20C is constant. By controlling the controller 21, it is possible to prevent pulsation from occurring in the high-pressure fuel supply pipe 13. When the maximum value of the discharge amount of the fuel supply units 20A, 20B, and 20C is v, the total discharge amount is constant at v.

  Here, the stroke is the height from the lowest point to the highest point when the boosting piston 52 reciprocates in the vertical direction. The stroke is set based on the position of the lowermost portion of the boosting piston 52 in the cylinder liner 53. The lowermost position of the boosting piston 52 is a position in the cylinder liner 53 where the volume of the space below the boosting piston 52 is minimized. Regardless of how the stroke is set by adjusting the stroke based on this position, all the liquid fuel in the reciprocating pump 50 is discharged in each cycle.

  In FIG. 4, the time interval between t (n−1) and tn (n is a natural number) is shown as an equal interval, but the time interval can be changed as appropriate. For example, the time interval between t1 and t2 may be increased by decreasing the discharge amount per time, that is, the speed of the boosting piston 52. Since the reciprocating pump 50 is driven using the linear actuator 30, the stroke of the boosting piston 52 can be freely adjusted.

  The controller 21 controls the drive of the linear actuator 30 so that the speed at which the boosting piston 52 descends (speed that moves in the second direction) is constant so that the discharge amount of the reciprocating pump 50 is constant. May be.

Since the plurality of fuel supply units 20A, 20B, and 20C can be controlled independently, the number of fuel supply units that are operated can be changed according to the fuel demand of the internal combustion engine 90. For example, only the fuel supply units 20A and 20B may be operated and the fuel supply unit 20C may be stopped.
FIG. 5 is a diagram illustrating an example of a change over time in the discharge amount when fuel is supplied only by the fuel supply units 20A and 20B. FIG. 5A illustrates an example of a change over time in the discharge amount of the fuel supply unit 20A. FIG. 5B is a diagram illustrating an example of a change over time in the discharge amount of the fuel supply unit 20B. FIG. 5C is a diagram illustrating the fuel supply units 20A and 20B in FIGS. 5A and 5B. It is a figure which shows an example of the time change of the total of each discharge amount.

From time t0 to t1, the discharge amount of the fuel supply unit 20A increases as shown in FIG. 5A, and at the same time, the discharge amount of the fuel supply unit 20B decreases as shown in FIG. 5B. At this time, since the increase amount of the discharge amount of the fuel supply unit 20A is equal to the decrease amount of the discharge amount of the fuel supply unit 20B, the total discharge amount is constant as shown in FIG.
From time t1 to t2, since the discharge amount of the fuel supply unit 20A is constant and the discharge amount of the fuel supply unit 20B is zero, the total discharge amount is constant as shown in FIG. 5C. .

From time t2 to t3, as shown in FIG. 5 (b), the discharge amount of the fuel supply unit 20B increases, and at the same time, the discharge amount of the fuel supply unit 20A decreases as shown in FIG. 5 (a). At this time, since the increase amount of the discharge amount of the fuel supply unit 20B is equal to the decrease amount of the discharge amount of the fuel supply unit 20A, the total discharge amount is constant as shown in FIG.
From time t3 to t4, since the discharge amount of the fuel supply unit 20B is constant and the discharge amount of the fuel supply unit 20A is zero, the total discharge amount is constant as shown in FIG. 5C. .
Thus, the total discharge amount can be made constant by shifting the discharge timing of the fuel supply units 20A and 20B.

In addition to the three fuel supply units 20A, 20B, and 20C, a fourth fuel supply unit (referred to as 20D) may be used.
FIG. 6 is a diagram showing an example of the change over time in the discharge amount when fuel is supplied from the four fuel supply units 20A, 20B, 20C, and 20D. FIG. 6A shows the discharge amount time of the fuel supply unit 20A. FIG. 6B is a diagram illustrating an example of a change in the discharge amount of the fuel supply unit 20B, and FIG. 6C is a diagram illustrating a change in the discharge amount of the fuel supply unit 20C over time. FIG. 6D is a diagram illustrating an example of a temporal change in the discharge amount of the fuel supply unit 20D, and FIG. 6E is a diagram illustrating the fuel supply unit of FIGS. 6A to 6D. It is a figure which shows an example of the time change of the total of each discharge amount of 20A, 20B, 20C, 20D.

From time t0 to t1, as shown in FIGS. 6 (a) and 6 (c), the amount of fuel supplied from the fuel supply units 20A and 20C increases, and simultaneously as shown in FIGS. 6 (b) and 6 (d). The discharge amount of the portions 20B and 20D decreases. At this time, since the sum of the increase amounts of the discharge amounts of the fuel supply units 20A and 20C and the sum of the decrease amount of the discharge amounts of the fuel supply units 20B and 20D are equal, as shown in FIG. The total is constant.
From time t1 to time t2, since the discharge amounts of the fuel supply units 20A and 20C are constant and the discharge amounts of the fuel supply units 20B and 20D are zero, as shown in FIG. Is constant.

From time t2 to t3, as shown in FIGS. 6 (b) and 6 (d), the amount of fuel supplied from the fuel supply units 20B and 20D increases, and simultaneously as shown in FIGS. 6 (a) and 6 (c). The discharge amount of the portions 20A and 20C decreases. At this time, since the sum of the increase in the discharge amount of the fuel supply units 20B and 20D is equal to the sum of the decrease in the discharge amount of the fuel supply units 20A and 20C, as shown in FIG. The total is constant.
From time t3 to t4, the discharge amount of the fuel supply units 20B and 20D is constant, and the discharge amount of the fuel supply units 20A and 20C is zero. Therefore, as shown in FIG. Is constant.
In this way, the total discharge amount can be made constant by shifting the discharge timings of the fuel supply units 20A and 20C and the fuel supply units 20B and 20D.

Note that the maximum discharge amounts of the plurality of fuel supply units 20A, 20B, and 20C may be different.
FIG. 7A is a diagram showing an example of the change over time of the discharge amount of the fuel supply unit 20A, and FIG. 7B is a diagram showing an example of the change over time of the discharge amount of the fuel supply unit 20B. (C) is a figure which shows an example of the time change of the discharge amount of 20 C of fuel supply parts, FIG.7 (d) is each discharge of fuel supply part 20A, 20B, 20C of Fig.7 (a)-(c). It is a figure which shows an example of the time change of the total of quantity. Here, when the maximum discharge amount of the fuel supply unit 20B is v1, and the maximum discharge amount of the fuel supply unit 20C is v2, the maximum discharge amount of the fuel supply unit 20A is v1 + v2 and each of the fuel supply units 20A, 20B, and 20C. The speed of the boosting piston 52 is adjusted so that the total discharge amount becomes v1 + v2. v1 and v2 may be different or the same.

From time t0 to t1, the discharge amount of the fuel supply unit 20A increases as shown in FIG. 7 (a), and at the same time, the discharge of the fuel supply units 20B and 20C, as shown in FIGS. 7 (b) and 7 (c). The amount decreases. At this time, since the increase amount of the discharge amount of the fuel supply unit 20A is equal to the sum of the decrease amounts of the discharge amounts of the fuel supply units 20B and 20C, the total discharge amount is constant as shown in FIG. Become.
From time t1 to t2, since the discharge amount of the fuel supply unit 20A is constant (v1 + v2) and the discharge amounts of the fuel supply units 20B and 20C are zero, as shown in FIG. The sum is constant (v1 + v2).

From time t2 to t3, as shown in FIGS. 7B and 7C, the discharge amount of the fuel supply units 20B and 20C increases, and at the same time, the discharge of the fuel supply unit 20A as shown in FIG. 7A. The amount decreases. At this time, since the sum of the increase amounts of the discharge amounts of the fuel supply units 20B and 20C is equal to the decrease amount of the discharge amount of the fuel supply unit 20A, the total discharge amount is constant as shown in FIG. Become.
From time t3 to t4, the discharge amount of the fuel supply unit 20B is constant at v1, the discharge amount of the fuel supply unit 20C is constant at v2, and the discharge amount of the fuel supply unit 20A is zero. As shown, the total discharge amount is constant (v1 + v2).
Thus, while making the stroke lengths different between the fuel supply unit 20A and the fuel supply units 20B and 20C, and by shifting the discharge timing of the fuel supply unit 20A and the fuel supply units 20B and 20C, the total discharge amount is made constant. can do.

  FIG. 8A is a diagram showing another example of the temporal change in the discharge amount of the fuel supply unit 20A, and FIG. 8B is a diagram showing another example of the temporal change in the discharge amount of the fuel supply unit 20B. FIG. 8C is a diagram showing another example of the change over time of the discharge amount of the fuel supply unit 20C, and FIG. 8D is the fuel supply unit 20A, 20B of FIGS. 8A to 8C. , 20C is a diagram illustrating an example of a temporal change in the total discharge amount of 20C.

From time t0 to t1, the discharge amount of the fuel supply unit 20A increases as shown in FIG. 8A, and at the same time, the discharge amount of the fuel supply unit 20B decreases as shown in FIG. 8B. As shown in FIG. 8C, the discharge amount of the fuel supply unit 20C is constant. At this time, since the increase amount of the discharge amount of the fuel supply unit 20A is equal to the decrease amount of the discharge amount of the fuel supply unit 20B, the total discharge amount is constant as shown in FIG.
From time t1 to t2, the discharge amount of the fuel supply units 20A and 20C is constant, and the discharge amount of the fuel supply unit 20B is zero. Therefore, as shown in FIG. 8D, the total discharge amount is constant. It becomes.

From time t2 to t3, as shown in FIG. 8B, the discharge amount of the fuel supply unit 20B increases, and at the same time, the discharge amount of the fuel supply unit 20C decreases as shown in FIG. 8C. As shown in FIG. 8A, the discharge amount of the fuel supply unit 20A is constant. At this time, since the increase amount of the discharge amount of the fuel supply unit 20B is equal to the decrease amount of the discharge amount of the fuel supply unit 20C, the total discharge amount is constant as shown in FIG.
From time t3 to t4, the discharge amount of the fuel supply units 20A and 20B is constant, and the discharge amount of the fuel supply unit 20C is zero. Therefore, as shown in FIG. 8D, the total discharge amount is constant. It becomes.

From time t4 to t5, as shown in FIG. 8C, the discharge amount of the fuel supply unit 20C increases, and at the same time, the discharge amount of the fuel supply unit 20B decreases as shown in FIG. 8B. As shown in FIG. 8A, the discharge amount of the fuel supply unit 20A is zero. At this time, since the increase amount of the discharge amount of the fuel supply unit 20C is equal to the decrease amount of the discharge amount of the fuel supply unit 20B, the total discharge amount is constant as shown in FIG.
From time t5 to t6, the discharge amount of the fuel supply units 20B and 20C is constant, and the discharge amount of the fuel supply unit 20A is zero. Therefore, as shown in FIG. 8D, the total discharge amount is constant. It becomes.

  Thus, even in the case shown in FIGS. 8A to 8D, the total amount of fuel discharged from the boost cylinders 51 of the fuel supply units 20A, 20B, and 20C is constant. The control unit 80 controls each of the controllers 21 of the fuel supply units 20A, 20B, and 20C, thereby preventing pulsation from occurring in the high-pressure fuel supply pipe 13. Note that if the maximum value of the discharge amount of the fuel supply units 20A, 20B, and 20C is v, the total discharge amount is constant at 2v.

  In FIG. 8, the time interval between t (n-1) and tn (n is a natural number) can be changed as appropriate. For example, by increasing the stroke of the boosting piston 52, the time interval between t (n-1) and tn is increased while keeping the speed of the boosting piston 52 constant (while keeping the discharge amount constant). Also good. For example, in FIG. 4, the time from t1 to t2 may be twice as long as the time from t3 to t4 or the time from t5 to t6.

  4 and 8, the discharge amount waveforms of the fuel supply units 20A, 20B, and 20C are the same and have different phases. However, the discharge amount waveforms of the fuel supply units 20A, 20B, and 20C may be different. Alternatively, the maximum discharge amount of the fuel supply units 20A, 20B, and 20C may be different.

  FIG. 9A is a diagram showing another example of the temporal change in the discharge amount of the fuel supply unit 20A, and FIG. 9B is a diagram showing another example of the temporal change in the discharge amount of the fuel supply unit 20B. FIG. 9C is a diagram showing another example of the change over time of the discharge amount of the fuel supply unit 20C, and FIG. 9D is the fuel supply unit 20A, 20B of FIGS. 9A to 9C. , 20C is a diagram illustrating an example of a temporal change in the total discharge amount of 20C.

  From time t0 to t1, the discharge amount of the fuel supply unit 20A increases as shown in FIG. 9A, and at the same time, the discharge amount of the fuel supply unit 20C decreases as shown in FIG. 9C. As shown in FIG. 9B, the discharge amount of the fuel supply unit 20B is zero. At this time, since the increase amount of the discharge amount of the fuel supply unit 20A is equal to the decrease amount of the discharge amount of the fuel supply unit 20C, the total discharge amount is constant as shown in FIG.

  From time t1 to time t2, as shown in FIG. 9B, the discharge amount of the fuel supply unit 20B increases, and at the same time, the discharge amount of the fuel supply unit 20C decreases as shown in FIG. 9C. As shown in FIG. 9A, the discharge amount of the fuel supply unit 20A is constant. At this time, since the increase amount of the discharge amount of the fuel supply unit 20B is equal to the decrease amount of the discharge amount of the fuel supply unit 20C, the total discharge amount is constant as shown in FIG.

  From time t2 to t3, as shown in FIGS. 9 (a) and 9 (b), the discharge amounts of the fuel supply units 20A and 20B are constant, and as shown in FIG. 9 (c), the fuel supply unit 20C Since the discharge amount is zero, as shown in FIG. 9D, the total discharge amount is constant.

  From time t3 to t4, as shown in FIG. 9C, the discharge amount of the fuel supply unit 20C increases, and at the same time, the discharge amount of the fuel supply unit 20A decreases as shown in FIG. 9A. As shown in FIG. 9B, the discharge amount of the fuel supply unit 20B is constant. At this time, since the increase amount of the discharge amount of the fuel supply unit 20C is equal to the decrease amount of the discharge amount of the fuel supply unit 20A, the total discharge amount is constant as shown in FIG.

  From time t4 to t5, as shown in FIG. 9A, the discharge amount of the fuel supply unit 20A increases, and at the same time, the discharge amount of the fuel supply unit 20C decreases as shown in FIG. 9C. As shown in FIG. 9B, the discharge amount of the fuel supply unit 20B is zero. At this time, since the increase amount of the discharge amount of the fuel supply unit 20A is equal to the decrease amount of the discharge amount of the fuel supply unit 20C, the total discharge amount is constant as shown in FIG.

  Thus, even in the case shown in FIGS. 9A to 9D, the total amount of fuel discharged from the boost cylinders 51 of the fuel supply units 20A, 20B, and 20C is constant. The control unit 80 controls each of the controllers 21 of the fuel supply units 20A, 20B, and 20C, thereby preventing pulsation from occurring in the high-pressure fuel supply pipe 13. If the maximum discharge amount of the fuel supply units 20A and 20B is v and the maximum discharge amount of the fuel supply unit 20C is 2v, the total discharge amount is constant at 2v. In this way, the fuel supply units 20A, 20B and the fuel supply unit 20C have different stroke lengths and speeds of the boosting piston 52, and the discharge timings of the fuel supply units 20A, 20B, 20C are shifted, thereby reducing the discharge amount. The sum can be constant.

  When the servo motor is used, the moving direction of the hydraulic piston 42 can be switched by switching the flow direction of the hydraulic oil supplied into the hydraulic cylinder 41 according to the forward / reverse rotation direction of the hydraulic pump 32. In this case, since the flow direction of the hydraulic oil is not switched by the direction switching valve, it is not necessary to continue the operation of the hydraulic pump 32 at the rated rotational speed, and energy is compared with the case where the hydraulic pump 32 is continuously operated at the rated rotational speed. Consumption can be reduced.

  In addition, since the plurality of fuel supply units 20A, 20B, and 20C are provided in parallel between the low pressure fuel supply pipe 12 and the high pressure fuel supply pipe 13, the number of fuel supply parts can be easily changed. Further, even when trouble occurs in any of the plurality of fuel supply units or when maintenance is performed, any one of the fuel supply units can be removed and the other fuel supply units can be continuously driven.

  Further, by providing a position sensor for detecting the position of the boosting piston 52, the speed and position of the boosting piston 52 can be adjusted with certainty.

In the above description, the case where three fuel supply units 20A, 20B, and 20C are used has been described. However, the present invention is not limited to this, and an arbitrary number of fuel supply units can be used. For example, an auxiliary fuel supply unit may be further provided in addition to the three fuel supply units 20A, 20B, and 20C. In this case, while the three fuel supply units 20A, 20B, and 20C are mainly used, the discharge amount decreases when the total discharge amount from the three fuel supply units 20A, 20B, and 20C decreases for some reason. The fuel may be discharged from an auxiliary fuel supply unit so as to supplement the amount.
Further, the shape of the reciprocating pump 50 is not limited to the shape shown in FIGS. 2 and 3, and a reciprocating pump having an arbitrary shape can be used.
In the above description, the fuel supply device mounted on the ship has been described, but the present invention is not limited to this. The linear actuator 30 and the reciprocating pump 50 can be installed on an arbitrary structure. For example, the linear actuator 30 and the reciprocating pump 50 may be mounted on the body of an automobile, or the linear actuator 30 and the reciprocating pump 50 may be installed on the floor of a building frame.

<Modification>
FIG. 10 is a view showing a fuel supply unit using the electric cylinder unit as the linear actuator 30. In addition, about the structure similar to FIG. 2, FIG. 3, the same code | symbol is attached | subjected and description is omitted.
The electric cylinder unit includes an electric motor 31, gears 35 a and 35 b, a ball nut 37, and a ball screw 38.
The gear 35a is rotated by the power of the electric motor 31, and the rotation of the gear 35a is transmitted to the gear 35b.
The gear 35 b is provided integrally with the ball nut 37 and transmits the rotation of the gear 35 a to the ball nut 37.
The ball nut 37 is screwed with the ball screw 38 and rotates together with the gear 35b.
The lower end of the ball screw 38 is connected to the upper end of the boosting piston 52 by a connecting portion 49. As the ball nut 37 rotates, the ball screw 38 moves in the axial direction. As the ball screw 38 moves in the axial direction, the boosting piston 52 also moves in the axial direction.
Also in this modification, the same effect as the case where a hydraulic cylinder unit is used as the linear actuator 30 can be obtained.
When the pump installation location is a non-explosion-proof location or a second type hazardous location, the rotation of the electric motor 31 may be transmitted to the ball nut using a pulley and a timing belt instead of the gears 35a and 35b. .

DESCRIPTION OF SYMBOLS 10 Fuel supply apparatus 11 Liquid fuel tank 12 Low pressure fuel supply pipe 13 High pressure fuel supply pipe 14 Heat exchanger 15 High temperature fuel supply pipe 16 Pressure regulation valve 17 Pressure gauge 20A, 20B, 20C Fuel supply part 21 Controller 30 Linear actuator 31 Electric motor 32 Hydraulic pump 33 First hydraulic pipe 34 Second hydraulic pipe 35a, 35b Gear 37 Ball nut 38 Ball screw 41 Hydraulic cylinder 42 Hydraulic piston 42b, 52b Piston ring 43 Working oil storage space 43a Upper chamber 43b Lower chamber 47 Piston rod 48 Heat insulating cavity 49 Connection 50 Reciprocating pump 51 Boosting cylinder 51a, 52a Rider ring 52 Boosting piston 53 Cylinder liner 54 Cover 55 Suction port 56 Discharge port 57 Rod packing 60 Valve box 61 Discharge flow path 62 Discharge valve body 3, 66 valve seat 64 intake passage 65 suction valve element 70 position sensor 80 control unit 90 engine

Claims (7)

A fuel supply device for supplying fuel into a combustion chamber of an internal combustion engine,
A low-pressure fuel supply pipe to which low-pressure fuel is supplied;
A high-pressure fuel supply pipe to which a high-pressure fuel supplied to the combustion chamber is supplied;
A plurality of fuel supply units provided between the low-pressure fuel supply pipe and the high-pressure fuel supply pipe, and pressurize the fuel in the low-pressure fuel supply pipe and supply the pressure to the high-pressure fuel supply pipe, respectively;
A control unit for controlling the plurality of fuel supply units;
With
The fuel supply device, wherein the control unit controls the plurality of fuel supply units so that a sum of discharge amounts per unit time of fuel discharged from each of the plurality of fuel supply units becomes a constant value.   The control unit controls the plurality of fuel supply units such that when the amount of fuel discharged from at least one fuel supply unit increases, the amount of fuel discharged from other fuel supply units decreases. The fuel supply device according to claim 1.   The control unit includes the plurality of fuel supply units such that the sum of the increase amounts in the fuel supply unit where the fuel discharge amount increases matches the sum of the decrease amounts of the fuel discharge amounts from the other fuel supply units. The fuel supply device according to claim 2, wherein the fuel supply device is controlled. Each of the fuel supply units
A linear actuator;
A boosting piston driven by the linear actuator and reciprocating in an axial direction; the fuel is sucked in when the boosting piston moves in a first axial direction; A reciprocating pump for boosting and discharging the fuel when moving in the direction of 2;
A controller controlled by the control unit and controlling the driving of the linear actuator;
The fuel supply device according to any one of claims 1 to 3, further comprising: The linear actuator is a hydraulic cylinder unit,
A hydraulic cylinder having a hydraulic oil storage space for storing the hydraulic oil, and arranged so that an axial direction thereof coincides with an axial direction of the boosting piston;
A hydraulic piston which is provided so as to be movable in the axial direction in the hydraulic cylinder, and divides the hydraulic oil containing space into a first chamber and a second chamber;
A piston rod connecting the hydraulic piston and the boosting piston;
Supplying the hydraulic oil to the first chamber moves the hydraulic piston in the first axial direction, and supplying the hydraulic oil to the second chamber causes the hydraulic piston to move in the second axial direction. A hydraulic pump to move to,
An electric motor that drives the hydraulic pump so that the hydraulic piston reciprocates in the axial direction;
The fuel supply device according to claim 4, wherein the controller controls movement of the hydraulic piston in the hydraulic cylinder by controlling the electric motor. The hydraulic cylinder unit is
One end is connected to the hydraulic pump, the other end is connected to the first chamber, all hydraulic fluid discharged from the hydraulic pump is supplied to the first chamber, and all hydraulic fluid discharged from the first chamber is discharged. A sealed first hydraulic line for returning hydraulic oil to the hydraulic pump;
One end is connected to the hydraulic pump, the other end is connected to the second chamber, all hydraulic fluid discharged from the hydraulic pump is supplied to the second chamber, and all hydraulic fluid discharged from the second chamber is discharged. A sealed second hydraulic line for returning hydraulic oil to the hydraulic pump;
The fuel supply device according to claim 5, further comprising: The linear actuator is an electric cylinder unit,
An electric motor;
A ball nut rotated by the power of the electric motor;
A ball screw that is engaged with the boosting piston in a state in which the ball nut is screwed and the axial direction coincides with the axial direction of the boosting piston, and moves in the axial direction by the rotation of the ball nut;
With
The fuel supply device according to any one of claims 1 to 4, wherein the controller controls movement of the ball screw in an axial direction by controlling the electric motor.