JP6586681B2 - Fuel supply device - Google Patents

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, NO _x , SO _x , and natural gas with low emissions have attracted attention as 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 a device for boosting liquid fuel and supplying it to an engine using a reciprocating pump. In the device of Patent Document 1, a piston of a reciprocating pump is driven in the axial 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, the fuel supply device that supplies fuel to the internal combustion engine using the reciprocating pump has a problem that pulsation occurs due to various causes. One possible cause of pulsation is the timing at which fuel is discharged from a reciprocating pump. In order to reduce pulsation, it is conceivable to shift the discharge timings from a plurality of reciprocating pumps. For example, the time fluctuation of the total discharge amount can be reduced by shifting the discharge timing by three reciprocating pumps by 1/3 period, but the time fluctuation is not completely lost.
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 apparatus that supplies liquefied fuel into a combustion chamber of an internal combustion engine,
A first reciprocating pump having a first boosting piston that reciprocates in the axial direction, and alternately sucking and discharging the liquefied fuel by reciprocating the first boosting piston in the axial direction;
A second reciprocating pump that has a second boosting piston that reciprocates in the axial direction, and alternately sucks and discharges the liquefied fuel by reciprocating the second boosting piston in the axial direction;
The first boosting piston and the second boosting piston are attached so as to be coaxial, and the first reciprocating pump and the first boosting piston are reciprocated in the axial direction by reciprocating the first boosting piston and the second boosting piston. A first linear actuator that causes the second reciprocating pump to alternately discharge the liquefied fuel;
A third reciprocating pump having a third boosting piston that reciprocates in the axial direction, and alternately sucking and discharging the liquefied fuel by reciprocating the third boosting piston in the axial direction;
A second linear actuator for reciprocating the third boosting piston in the axial direction;
A controller for controlling driving of the first linear actuator and the second linear actuator ,
The controller determines an absolute value of a maximum acceleration for accelerating a moving speed of the third boosting piston in the suction movement direction when the third reciprocating pump sucks the liquefied fuel. Controlling the third reciprocating pump so as to be smaller than the absolute value of the maximum acceleration for accelerating the moving speed of the third boosting piston when discharging the liquefied fuel;
It is characterized by that.

In the case where the output of the internal combustion engine is constant, the controller
The drive of the second linear actuator is adjusted so that the total discharge speed of the liquefied fuel discharged from each of the first reciprocating pump, the second reciprocating pump, and the third reciprocating pump is constant. It is preferable.

The fuel supply device further includes a fourth boosting piston that reciprocates in the axial direction, and a fourth reciprocation that alternately sucks and discharges the liquefied fuel as the fourth boosting piston reciprocates in the axial direction. A pump,
A fifth reciprocating pump having a fifth boosting piston that reciprocates in the axial direction, and alternately sucking and discharging the liquefied fuel by reciprocating the fifth boosting piston in the axial direction;
The fourth boosting piston and the fifth boosting piston are mounted so as to be coaxial, and the fourth boosting piston and the fifth boosting piston are reciprocated in the axial direction, thereby allowing the fourth reciprocating pump and A third linear actuator that causes the fifth reciprocating pump to alternately discharge the liquefied fuel ,
The controller may control driving of the third linear actuator in addition to the first linear actuator and the second linear actuator.

In the case where the output of the internal combustion engine is constant, the controller
The sum of the discharge speeds of the liquefied fuel discharged from each of the first reciprocating pump, the second reciprocating pump, the third reciprocating pump, the fourth reciprocating pump, and the fifth reciprocating pump is constant. It is preferable to adjust the drive of the second linear actuator so that

The controller has a maximum speed in the reciprocating motion of the fourth pressure increasing piston and the fifth pressure increasing piston when the speed in the reciprocating motion of the first pressure increasing piston and the second pressure increasing piston is minimum, And when the speed in the reciprocating motion of the first boosting piston and the second boosting piston is maximized, the speed in the reciprocating motion of the fourth boosting piston and the fifth boosting piston is minimized. Preferably, the first linear actuator and the third linear actuator are controlled.
Further, the controller is configured so that a suction time when the third reciprocating pump sucks the liquefied fuel is longer than a discharge time when the third reciprocating pump discharges the liquefied fuel. It is preferable to control the third reciprocating pump.
The controller controls driving of the third reciprocating pump so that the third boosting piston reciprocates a predetermined moving distance at a predetermined cycle, and the third reciprocating pump supplies the liquefied fuel. The absolute value of the maximum acceleration for accelerating the moving speed of the third boosting piston in the suction movement direction during inhalation is a single vibration motion of the third boosting piston over the predetermined moving distance in the predetermined cycle. It is preferable that the absolute value of the maximum acceleration for accelerating the moving speed of the third boosting piston in the suction movement direction when the liquefied fuel is sucked back and forth is reduced.

  According to the present invention, the second linear is set so that the total discharge amount per unit time of the fuel discharged from each of the first reciprocating pump, the second reciprocating pump, and the third reciprocating pump becomes a constant amount. By adjusting the driving of the actuator, the pulsation of the pressure of the fuel in the high-pressure fuel supply pipe can be reduced.

It is a schematic block diagram of 10 A of fuel supply apparatuses of 1st Embodiment. It is sectional drawing of 30 A of linear actuators, and reciprocating pump 50A, 50B. It is sectional drawing of the linear actuator 30B and the reciprocating pump 50C. (A) is a figure which shows an example of the time fluctuation | variation of the discharge amount of the reciprocating pump 50A, (b) is a figure which shows an example of the time fluctuation | variation of the discharge amount of the reciprocating pump 50B, (c) is a reciprocating type. It is a figure which shows an example of the time fluctuation | variation of the discharge amount of the pump 50C, (d) is an example of the total time fluctuation | variation of each discharge amount of the reciprocating pumps 50A, 50B, and 50C of FIG. FIG. It is a figure which shows an example of the time fluctuation of the speed of piston 52C for pressure | voltage rise. It is a figure which shows another example of the time fluctuation of the speed of piston 52C for pressure | voltage rise. It is a schematic block diagram of the fuel supply apparatus 10B which concerns on 2nd Embodiment. It is sectional drawing of 30 C of linear actuators and reciprocating pumps 50D and 50E. (A) is a figure which shows an example of the time fluctuation | variation of the total amount of discharge amount of reciprocating pump 50A, 50B, (b) shows an example of the time fluctuation | variation of the total amount of discharge amount of reciprocating pump 50D, 50E. (C) is a figure which shows an example of the time fluctuation | variation of the total amount of discharge amount of reciprocating pump 50A, 50B, 50D, 50E, (d) is a figure of the time fluctuation | variation of the discharge amount of reciprocating pump 50C. It is a figure which shows an example, (e) is a figure which shows an example of the time fluctuation | variation of the total amount of the discharge amount of reciprocating pump 50A, 50B, 50C, 50D, 50E. (A) is a figure which shows an example of the time fluctuation | variation of the total amount of discharge amount of reciprocating pump 50A, 50B, (b) is another example of the time fluctuation | variation of the total amount of discharge amount of reciprocating pump 50D, 50E. (C) is a figure which shows another example of the time fluctuation of the total amount of discharge amount of reciprocating pump 50A, 50B, 50D, 50E, (d) is the discharge amount of reciprocating pump 50C. It is a figure which shows another example of this time fluctuation | variation, (e) is a figure which shows another example of the time fluctuation | variation of the total amount of discharge amount of reciprocating pump 50A, 50B, 50C, 50D, 50E.

Hereinafter, a fuel supply device according to an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a schematic configuration diagram of a fuel supply apparatus 10A according to the first embodiment. As shown in FIG. 1, the fuel supply device 10 </ b> A 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 device 10A includes a liquid fuel tank 11, a low-pressure fuel supply pipe 12, a fuel supply unit 20A, a high-pressure fuel supply pipe 13, a heat exchanger 14, and a high-temperature fuel supply pipe 15. A pressure regulating valve 16, a pressure gauge 17, and a control unit 80. All of these components of the fuel supply device 10A 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 is a pressure according to the temperature of the liquid fuel in the liquid fuel tank 11, the liquid level height, and the like. In order to increase this pressure and secure an effective suction head (NPSH: Net Positive Suction Head) and to facilitate the supply of liquid fuel to the fuel supply unit 20A, the liquid fuel tank 11 is disposed at a higher position than the fuel supply unit 20A. Has been.
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 unit 20 </ b> A is provided between the low pressure fuel supply pipe 12 and the high pressure fuel supply pipe 13. The fuel supply unit 20A includes a controller 21, linear actuators 30A and 30B, and reciprocating pumps 50A, 50B, and 50C.
The reciprocating pumps 50 </ b> A, 50 </ b> B, 50 </ b> C increase the pressure of the liquid fuel supplied from the low pressure fuel supply pipe 12 and supply it to the heat exchanger 14 via the high pressure fuel supply pipe 13. The high-pressure fuel supply pipe 13 may be provided with a pulsation damper (accumulator) 13a that absorbs pressure fluctuations in the internal fuel.
The low pressure fuel pipe 12 and the high pressure fuel supply pipe 13 may be detachable from the reciprocating pumps 50A, 50B, 50C.

  The linear actuator 30A (first linear actuator) is a piston (first boosting piston) of a reciprocating pump 50A (first reciprocating pump) and a piston (second boosting piston) of a reciprocating pump 50B (second reciprocating pump). ). The linear actuator 30B (second linear actuator) drives a piston (third boosting piston) of a reciprocating pump 50C (third reciprocating pump). By using the linear actuators 30A, 30B, the pistons of the reciprocating pumps 50A, 50B, 50C can be driven at a lower speed than when the crankshaft is used. In addition, during the piston stroke, it is possible to control the drive so that the piston moves at a constant speed except when the liquid inflow of the reciprocating pump starts, the liquid pressure starts, and the liquid pressure ends. For example, a hydraulic cylinder unit, an electric cylinder unit, or the like can be used as the linear actuators 30A and 30B. In the following embodiment, a case where a hydraulic cylinder unit is used as the linear actuators 30A and 30B will be described. However, the linear actuators 30A and 30B are not limited to the hydraulic cylinder unit.

  The controller 21 controls the linear actuators 30A and 30B by a control signal input from the control unit 80, as will be described later. Further, as will be described later, a position signal indicating the position of the piston of the reciprocating pumps 50A, 50B, 50C is input to the controller 21. The controller 21 controls the linear actuators 30A and 30B so that the discharge amounts of the reciprocating pumps 50A, 50B, and 50C are adjusted according to the position signal.

  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. Alternatively, the liquid fuel may be heated by heat exchange with hot water heated by the combustion heat of the boil-off gas.

The high temperature fuel supply pipe 15 is provided with a pressure regulating valve 16, 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 pumps 50A, 50B, and 50C by outputting a control signal to the controller 21 of the fuel supply unit 20A. The discharge amounts of the reciprocating pumps 50A, 50B, and 50C are 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.

  Liquid fuel tank 11, low-pressure fuel supply pipe 12, linear actuators 30A, 30B, reciprocating pumps 50A, 50B, 50C, high-pressure fuel supply pipe 13, heat exchanger 14, high-temperature fuel supply pipe 15, pressure regulating valve 16, pressure gauge 17 Is located in the hazardous area. On the other hand, the controller 21 and the control unit 80 are generally non-explosion-proof products, and are arranged in a non-hazardous area separated from the hazardous area by an explosion-proof partition wall or in a non-explosion-proof area sufficiently separated from the dangerous area. There must be.

Next, the configuration of the linear actuators 30A and 30B and the reciprocating pumps 50A, 50B, and 50C will be described with reference to FIGS.
In the present embodiment, the linear actuator 30A and the reciprocating pumps 50A and 50B are arranged with the same axial direction, and the linear actuator 30B and the reciprocating pump 50C are arranged with the same axial direction. 2 is the axial direction of the linear actuator 30A and the reciprocating pumps 50A and 50B. In FIG. 2, the reciprocating pump 50A is arranged on the left side of the linear actuator 30A, and the reciprocating pump is on the right side of the linear actuator 30A. 50B is arranged. 3 is the axial direction of the linear actuator 30B and the reciprocating pump 50C. In FIG. 3, the reciprocating pump 50C is disposed on the left side of the linear actuator 30C.

As shown in FIG. 2, the linear actuator 30A includes an inverter 31A, an electric motor 32A, a hydraulic pump 33A, a first hydraulic pipe 34A, a second hydraulic pipe 35A, a hydraulic cylinder 41A, a hydraulic piston 42A, and piston rods 47A and 47B. Etc.
As shown in FIG. 3, the linear actuator 30B includes a servo amplifier 31B, an electric motor 32B, a hydraulic pump 33B, a first hydraulic pipe 34B, a second hydraulic pipe 35B, a hydraulic cylinder 41B, a hydraulic piston 42B, and a piston rod. 47C, 47D, etc. Of the configuration of the linear actuator 30B, the configuration other than the servo amplifier 31B and the electric motor 32B is the same as that of the linear actuator 30A. Omit.

The inverter 31A is controlled by the controller 21 and drives the electric motor 32A. An inverter motor is used as the electric motor 32A. The electric motor 32A is driven by the inverter 31A and rotates the hydraulic pump 33A.
The servo amplifier 31B is controlled by the controller 21 and drives the electric motor 32B. A servo motor is used as the electric motor 32B. The electric motor 32B is driven by the servo amplifier 31B and rotates the hydraulic pump 33B. Since a servo motor is used as the electric motor 32B, the response speed is faster than that of the electric motor 32A using an inverter motor, and fine position control can be performed.

  The hydraulic pump 33A is connected to the first hydraulic pipe 34A and the second hydraulic pipe 35A. The hydraulic pump 33A is driven by an electric motor 32A. The direction in which the hydraulic oil is discharged from the hydraulic pump 33A is switched according to the forward and reverse rotation directions of the electric motor 32A. For example, during the forward rotation of the electric motor 32A, the hydraulic pump 33A sucks the working oil in the first hydraulic pipe 34A and discharges the sucked working oil to the second hydraulic pipe 35A side. When the electric motor 32A rotates in the reverse direction, the hydraulic pump 33A sucks the hydraulic oil in the second hydraulic pipe 35A and discharges the sucked hydraulic oil to the first hydraulic pipe 34A side. The flow rate and pressure of the hydraulic oil in the first hydraulic pipe 34A and the second hydraulic pipe 35A are determined by the discharge amount of the hydraulic pump 33A. The flow rate and pressure of the hydraulic oil can be adjusted by the rotational speed of the electric motor 32A.

  As the hydraulic oil, any hydraulic oil can be adopted from petroleum hydraulic oil, synthetic hydraulic oil, aqueous hydraulic oil and the like.

  The hydraulic cylinder 41A has a cylindrical shape, and the horizontal direction in FIG. The hydraulic cylinder 41A has a hydraulic oil storage space 43A for storing hydraulic oil, and a hydraulic piston 42A is accommodated in the hydraulic oil storage space 43A so as to be movable in the axial direction.

  The hydraulic piston 42A partitions the hydraulic oil containing space 43A into a first chamber 43a on the left side (reciprocating pump 50A side) of the hydraulic piston 42A and a second chamber 43b on the right side (reciprocating pump 50B side) of the hydraulic piston 42A. To do. The hydraulic piston 42A is a double rod type, and has piston rods 47A and 47B that protrude outward from both ends (left and right ends in FIG. 2) of the hydraulic cylinder 41A. The piston rods 47A and 47B move in the axial direction together with the hydraulic piston 42A. Since the hydraulic piston 42A is a double rod type and the cross-sectional areas of the piston rods 47A and 47B are equal, the amount of decrease in the volume of the first chamber 43a when the hydraulic piston 42A moves to the left in FIG. The increase in volume is equal.

  Also, a first through hole 44A that communicates with the first chamber 43a is provided at the left end of the side wall of the hydraulic cylinder 41A, and a second penetration that communicates with the second chamber 43b is provided at the right end of the sidewall of the hydraulic cylinder 41A. A hole 45A is provided. The outer opening of the first through hole 44A is connected to the first hydraulic pipe 34A, and the outer opening of the second through hole 45A is connected to the second hydraulic pipe 35A.

  On the other hand, as shown in FIG. 3, the hydraulic cylinder 41B of the linear actuator 30B has a hydraulic oil storage space 43B for storing hydraulic oil, and the hydraulic piston 42B can move in the axial direction in the hydraulic oil storage space 43B. Is housed in. The hydraulic piston 42B includes a first chamber 43a on the left side (reciprocating pump 50C side) of the hydraulic oil containing space 43B and a second chamber 43b on the right side (opposite side of the reciprocating pump 50C) of the hydraulic piston 42B. Divide into The hydraulic piston 42B is a double rod type, and has piston rods 47C and 47D that protrude outward from both end portions (left and right end portions in FIG. 3) of the hydraulic cylinder 41B. The piston rods 47C and 47D move in the axial direction together with the hydraulic piston 42B. Since the hydraulic piston 42B is a double rod type and the cross-sectional areas of the piston rods 47C and 47D are equal, the amount of decrease in the volume of the first chamber 43a when the hydraulic piston 42B moves to the left side in FIG. The increase in volume is equal.

The outer end portion (left side in FIG. 2) of the piston rod 47A is connected to the right end portion of the boosting piston 52A of the reciprocating pump 50A by a connecting portion 49A. The connecting portion 49A may have a function of adjusting the misalignment between the piston rod 47A and the boosting piston 52A.
The outer end portion (right side in FIG. 2) of the piston rod 47B is connected to the left end portion of the boosting piston 52B of the reciprocating pump 50B by a connecting portion 49B. The connecting portion 49B may have a function of adjusting the misalignment between the piston rod 47B and the boosting piston 52B.
The outer end portion (left side in FIG. 3) of the piston rod 47C is connected to the right end portion of the boosting piston 52C of the reciprocating pump 50C by a connecting portion 49C. The connecting portion 49C may have an axial misalignment adjusting function of the piston rod 47C and the boosting piston 52C.

As the reciprocating pumps 50A, 50B, and 50C, for example, a reciprocating pump having the same structure as described in Japanese Patent No. 5519857 can be used.
The reciprocating pump 50A includes a boosting cylinder 51A, a boosting piston 52A, a cylinder liner 53A, a cover 54A, a valve box 60A, and the like. The reciprocating pump 50B includes a boosting cylinder 51B, a boosting piston 52B, a cylinder liner 53B, a cover 54B, a valve box 60B, and the like. The reciprocating pump 50C includes a boosting cylinder 51C, a boosting piston 52C, a cylinder liner 53C, a cover 54C, a valve box 60C, and the like.
In the following description, the configuration of the reciprocating pump 50A will be mainly described. Among the configurations of the reciprocating pumps 50B and 50C, the same configurations as the reciprocating pump 50A are denoted by the same numerals and different letter symbols. Omit the explanation.

  The pressure increasing cylinder 51A has a space for accommodating the cylinder liner 53A and the valve box 60A. The boosting piston 52A is accommodated in the boosting cylinder 51A so as to be movable in the axial direction within the cylinder liner 53A. The valve box 60A is fixed in the boosting cylinder 51 by a cover 54A.

A suction port 55A is provided on the side wall of the boosting cylinder 51 at a position where the valve box 60A is fixed. The suction port 55A is connected to the low-pressure fuel supply pipe 12.
The cover 54A is fixed to the end of the boosting cylinder 51A opposite to the side where the boosting piston 52A is inserted. The cover 54 is provided with a discharge port 56A penetrating in the axial direction of the boosting piston 52A. The discharge port 56 </ b> A is connected to the high-pressure fuel supply pipe 13.

The outer end portion (right end portion in FIG. 2) of the boosting piston 52A is connected to one end (left end portion in FIG. 2) of the piston rod 47A by the connecting portion 49A, and the boosting piston 52A is connected to the piston rod 47A. It moves in conjunction with the axial direction (left and right direction in FIG. 2).
Further, a position sensor 70A is provided in the boosting piston 52A. The position sensor 70 </ b> A detects the position of the boosting piston 52 </ b> A in the axial direction (left-right direction in FIG. 2) and outputs a position signal to the controller 21. The speed of the boosting piston 52A can be obtained by differentiating the displacement of the boosting piston 52A with time using the position signal. That is, the position sensor can also be used as a speed sensor. Furthermore, the acceleration of the boosting piston 52A can be obtained by differentiating the speed of the boosting piston 52A with respect to time. That is, the position sensor 70A can also be used as an acceleration sensor.

As the position sensor 70A, for example, a magnetostrictive position sensor or an ultrasonic sensor can be used. Here, a case where a magnetostrictive position sensor is used will be described.
Specifically, the position sensor 70 </ b> A includes a sensor probe 71 (magnetostrictive line), an annular magnet 72, and a detector 73. The sensor probe 71 is provided in parallel with the boosting piston 52A. The annular magnet 72 is attached to the boosting piston 52A so as to move in the axial direction along with the boosting piston 52A 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. Since the magnetic field is applied in the axial direction of the sensor probe 71 at the same position as the annular magnet 72 of the sensor probe 71, 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 annular magnet 72 and outputs a position signal indicating the position of the boosting piston 52 in the axial direction to the controller 21.

As shown in FIG. 3, the boosting piston 52C is also provided with a position sensor 70C similar to the boosting piston 52A.
Instead of providing the position sensor 70A to the boosting piston 52A, it may be attached to the boosting piston 52B, or may be attached to either of the piston rods 47A and 47B. Further, the position sensor 70C may be attached to either the piston rod 47C or 47D instead of being provided in the boosting piston 52C.

The valve box 60A is fixed between the cylinder liner 53A and the cover 54A in the boosting cylinder 51A. The valve box 60A is provided with a discharge flow path 61A, a discharge check valve 62A, a suction flow path 64A, a suction check valve 65A, and the like.
The discharge passage 61A is provided so as to penetrate the valve box 60A in the axial direction of the boosting piston 52A. The opening on the cover 54A side of the discharge channel 61 is provided at a position facing the discharge port 56A of the cover 54A. A discharge check valve 62A for allowing fluid flow from the cylinder liner 53A side to the cover 54A side while preventing fluid flow from the cover 54A side to the cylinder liner 53A side is provided inside the discharge flow path 61A. It has been.

  The suction flow path 64A is provided so as to communicate with the space in the cylinder liner 53A from the outer wall of the valve box 60A. The opening on the outer wall side of the valve box 60A of the suction flow path 64A is provided at a position facing the suction port 55A of the boosting cylinder 51A. The suction flow path 64A is provided with a check valve 65A for suction that allows a fluid flow from the suction port 55A side to the cylinder liner 53A side and prevents a fluid flow from the cylinder liner 53A side to the suction port 55A side. It has been.

[Operation of linear actuator and reciprocating pump]
Next, operations of the linear actuator 30A and the reciprocating pumps 50A and 50B will be described.
First, the hydraulic pump 33A is driven by the electric motor 32A, and the hydraulic oil in the first chamber 43a is discharged from the first through hole 44A as shown by the solid line arrow in FIG. The second hydraulic pipe 35A is supplied to the second chamber 43b from the second through hole 45A. Then, the hydraulic piston 42A moves to the left in FIG. 2 in the hydraulic oil accommodating space 43A so that the volume of the second chamber 43b increases and the volume of the first chamber 43a decreases. Since the first hydraulic pipe 34A and the second hydraulic pipe 35A do not have a branch or the like, all the hydraulic fluid that has flowed out of the first chamber 43a is supplied to the second chamber 43b.

  When the hydraulic piston 42A moves to the left in FIG. 2, in the reciprocating pump 50A, the boosting piston 52A connected to the left end of the piston rod 47A by the connecting portion 49A is moved to the left in FIG. Move to. Then, the liquid fuel inside the cylinder liner 53A and in the space on the left side of the boosting piston 52A is discharged to the high-pressure fuel supply pipe 13 through the discharge passage 61A and the discharge port 56A. At this time, the discharge check valve 62A in the discharge flow path 61A is in an open state, and the suction check valve 65A in the suction flow path 64A is in a closed state.

  On the other hand, when the hydraulic piston 42A moves in the left direction in FIG. 2, in the reciprocating pump 50B, the boosting piston 52B connected to the right end of the piston rod 47B by the connecting portion 49B is within the cylinder liner 53B in FIG. Move left. Then, the liquid fuel is supplied from the suction port 55B through the suction flow path 64B to the space inside the cylinder liner 53B and on the right side of the boosting piston 52B. At this time, the suction check valve 65B in the suction flow path 64B is open, and the discharge check valve 62B in the discharge flow path 61B is closed.

  Next, the rotation direction of the electric motor 32A is switched by the controller 21, the hydraulic pump 33A is driven in the opposite direction, and the hydraulic oil in the second chamber 43b is discharged from the second through hole 45A as shown by the broken line arrow in FIG. It is discharged and supplied to the first chamber 43a from the first through hole 44A through the second hydraulic pipe 35A and the first hydraulic pipe 34A. Then, the hydraulic piston 42A moves to the right in FIG. 2 in the hydraulic oil accommodating space 43 so that the volume of the second chamber 43b decreases and the volume of the first chamber 43a increases. Since the first hydraulic pipe 34A and the second hydraulic pipe do not have a branch or the like, all the hydraulic fluid that has flowed out of the second chamber 43b is supplied to the first chamber 43a.

  When the hydraulic piston 42A moves to the right in FIG. 2, in the reciprocating pump 50A, the boosting piston 52A connected to the left end of the piston rod 47A by the connecting portion 49A is moved to the right in FIG. Move to. Then, liquid fuel is supplied from the suction port 55A through the suction flow path 64A to the space inside the cylinder liner 53A and to the left of the boosting piston 52A. At this time, the suction check valve 65A in the suction flow path 64A is open, and the discharge check valve 62A in the discharge flow path 61A is closed.

  On the other hand, when the hydraulic piston 42A moves in the right direction in FIG. 2, in the reciprocating pump 50B, the boosting piston 52B connected to the right end of the piston rod 47B at the connecting portion 49B is within the cylinder liner 53B as shown in FIG. Move to the right. Then, the liquid fuel inside the cylinder liner 53B and in the space on the right side of the boosting piston 52B is discharged to the high-pressure fuel supply pipe 13B through the discharge passage 61B and the discharge port 56B. At this time, the discharge check valve 62B in the discharge flow path 61B is open, and the suction check valve 65B in the suction flow path 64B is closed.

  In this way, by switching the rotation direction of the electric motor 32A and switching the driving direction of the hydraulic pump 33A, the hydraulic oil is alternately passed between the first chamber 43a and the second chamber 43b, and the hydraulic piston 42A is boosted. The reciprocating pump 50A and the reciprocating pump 50B can alternately perform suction and discharge of liquid fuel by reciprocating the left and right pistons 52A and the boosting piston 52B in FIG. Further, the discharge of the liquid fuel from the reciprocating pump 50A and the discharge of the liquid fuel from the reciprocating pump 50B can be performed alternately.

Next, operations of the linear actuator 30B and the reciprocating pump 50C will be described.
First, the hydraulic pump 33B is driven by the electric motor 32B, and the hydraulic oil in the first chamber 43a is discharged from the first through hole 44B as shown by the solid line arrow in FIG. 2 is supplied from the second through hole 45B to the second chamber 43b via the second hydraulic pipe 35B. Then, the hydraulic piston 42B moves in the left direction of FIG. 3 in the hydraulic oil accommodating space 43B so that the volume of the second chamber 43b increases and the volume of the first chamber 43a decreases. Since the first hydraulic pipe 34B and the second hydraulic pipe 35B do not have a branch or the like, all the hydraulic fluid that has flowed out of the first chamber 43a is supplied to the second chamber 43b.

  When the hydraulic piston 42B moves to the left in FIG. 3, in the reciprocating pump 50C, the boosting piston 52C connected to the left end of the piston rod 47C by the connecting portion 49C is moved to the left in FIG. 3 in the cylinder liner 53C. Move to. Then, the liquid fuel inside the cylinder liner 53C and in the space on the left side of the boosting piston 52C is discharged to the high-pressure fuel supply pipe 13 through the discharge passage 61C and the discharge port 56C. At this time, the discharge check valve 62C in the discharge flow path 61C is open, and the suction check valve 65C in the suction flow path 64C is closed.

  Next, the rotation direction of the electric motor 32B is switched by the controller 21, the hydraulic pump 33B is driven in the opposite direction, and the hydraulic oil in the second chamber 43b is discharged from the second through hole 45B as indicated by the broken line arrow in FIG. It is discharged and supplied from the first through hole 44B to the first chamber 43a through the second hydraulic pipe 35B and the first hydraulic pipe 34B. Then, the hydraulic piston 42B moves to the right in FIG. 3 in the hydraulic oil accommodating space 43B so that the volume of the second chamber 43b decreases and the volume of the first chamber 43a increases. Since the first hydraulic pipe 34B and the second hydraulic pipe 35B do not have a branch or the like, all the hydraulic fluid that has flowed out of the second chamber 43b is supplied to the first chamber 43a.

  When the hydraulic piston 42B moves to the right in FIG. 3, in the reciprocating pump 50C, the boosting piston 52C connected to the left end of the piston rod 47C at the connecting portion 49C is moved to the right in FIG. 3 in the cylinder liner 53C. Move to. Then, the liquid fuel is supplied from the suction port 55C through the suction flow path 64C to the space inside the cylinder liner 53C and on the left side of the boosting piston 52C. At this time, the suction check valve 65C in the suction flow path 64C is open, and the discharge check valve 62C in the discharge flow path 61C is closed.

  In this way, by switching the rotation direction of the electric motor 32B and switching the driving direction of the hydraulic pump 33B, the hydraulic oil is alternately transferred between the first chamber 43a and the second chamber 43b, and the hydraulic piston 42B and the pressure booster are increased. The piston 52C can be reciprocated in the left-right direction in FIG. 3, and the reciprocating pump 50C can alternately perform suction and discharge of liquid fuel.

  Since the reciprocating pump 50A and the reciprocating pump 50B are driven by the same linear actuator 30A, the amount of fuel discharged by the reciprocating pump 50A and the reciprocating pump 50B cannot be controlled independently. On the other hand, since the reciprocating pump 50C is driven by a linear actuator 30B different from the reciprocating pump 50A and the reciprocating pump 50B, the amount of fuel discharged by the reciprocating pump 50C is independent of the reciprocating pump 50A and the reciprocating pump 50B. Can be controlled.

  In the present embodiment, when the output of the internal combustion engine 90 is constant, the discharge speed of fuel discharged from each of the reciprocating pump 50A, the reciprocating pump 50B, and the reciprocating pump 50C (the amount of fuel discharged per unit time) ) Is preferably adjusted so that the controller 21 adjusts the driving of the linear actuator 30B.

  Specifically, when the total discharge amount of the reciprocating pump 50A and the reciprocating pump 50B decreases, the discharge amount of the reciprocating pump 50C is increased so as to compensate for the decreased amount. When the total discharge amount of the pump 50B increases, the discharge amount of the reciprocating pump 50C may be reduced so as to offset the increase amount.

  FIG. 4A is a diagram illustrating an example of time variation of the discharge amount of the reciprocating pump 50A, and FIG. 4B is a diagram illustrating an example of time variation of the discharge amount of the reciprocating pump 50B. (C) is a figure which shows an example of the time fluctuation | variation of the discharge amount of reciprocating pump 50C, FIG.4 (d) is each discharge of reciprocating pump 50A, 50B, 50C of Fig.4 (a)-(c). It is a figure which shows an example of the time fluctuation | variation of the total of quantity. FIG. 4 is an example of time fluctuation when the output of the internal combustion engine 90 is constant.

From time t0 to t1, the discharge amount of the reciprocating pump 50A increases as shown in FIG. 4A, and at the same time, the discharge amount of the reciprocating pump 50C decreases as shown in FIG. 4C. As shown in FIG. 4B, the discharge amount of the reciprocating pump 50B is zero. At this time, since the increase rate of the discharge amount of the reciprocating pump 50A is equal to the decrease rate of the discharge amount of the reciprocating pump 50C, the total discharge amount is constant as shown in FIG.
From time t1 to t2, the discharge amount of the reciprocating pump 50A is constant as shown in FIG. 4A, and as shown in FIGS. 4B and 4C, the other reciprocating pumps 50B, Since the discharge amount of 50C is zero, the total discharge amount is constant as shown in FIG.
From time t2 to t3, the discharge amount of the reciprocating pump 50A decreases as shown in FIG. 4A, and at the same time, the discharge amount of the reciprocating pump 50C increases as shown in FIG. 4C. As shown in FIG. 4B, the discharge amount of the reciprocating pump 50B is zero. At this time, since the increase rate of the discharge amount of the reciprocating pump 50C is equal to the decrease rate of the discharge amount of the reciprocating pump 50A, the total discharge amount is constant as shown in FIG.

From time t3 to t4, the discharge amount of the reciprocating pump 50B increases as shown in FIG. 4B, and at the same time, the discharge amount of the reciprocating pump 50C decreases as shown in FIG. 4C. As shown in FIG. 4A, the discharge amount of the reciprocating pump 50A is zero. At this time, since the increase rate of the discharge amount of the reciprocating pump 50B is equal to the decrease rate of the discharge amount of the reciprocating pump 50C, the total discharge amount is constant as shown in FIG.
From time t4 to t5, as shown in FIG. 4B, the discharge amount of the reciprocating pump 50B is constant, and as shown in FIGS. 4A and 4C, the other reciprocating pumps 50B, Since the discharge amount of 50C is zero, the total discharge amount is constant as shown in FIG.
From time t5 to t6, the discharge amount of the reciprocating pump 50B decreases as shown in FIG. 4B, and at the same time, the discharge amount of the reciprocating pump 50C increases as shown in FIG. 4C. As shown in FIG. 4A, the discharge amount of the reciprocating pump 50B is zero. At this time, since the increase rate of the discharge amount of the reciprocating pump 50C is equal to the decrease rate of the discharge amount of the reciprocating pump 50B, the total discharge amount is constant as shown in FIG.

  In this way, the controller 21 adjusts the drive of the linear actuator 30B in accordance with the drive of the linear actuator 30A so that the total amount of fuel discharged from each of the reciprocating pumps 50A, 50B, 50C is constant. Thus, pulsation can be prevented from occurring in the high-pressure fuel supply pipe 13. If the maximum value of the discharge amount of the reciprocating pumps 50A, 50B, and 50C is v, the total discharge amount is constant at v.

  In order to prevent cavitation in the boost cylinders 51A, 51B, 51C, it is preferable to control the pressure in the boost cylinder 51 so as not to be lower than the vapor pressure of the fuel. Specifically, by reducing the maximum acceleration of the boosting pistons 52A, 52B, 52C when the reciprocating pump 50 sucks fuel, the pressure in the boosting cylinders 51A, 51B, 51C is less than the vapor pressure of the fuel. Can be prevented.

  Here, when the liquid fuel is discharged by the reciprocating pump 50A, the liquid fuel is sucked by the reciprocating pump 50B. When the liquid fuel is discharged by the reciprocating pump 50B, the liquid is discharged by the reciprocating pump 50A. Inhalation of fuel is performed. Since the discharge amounts of the reciprocating pumps 50A and 50B depend on the speeds of the boosting pistons 52A and 52B, decreasing the maximum acceleration of the boosting pistons 52A and 52B increases the discharge amounts of the reciprocating pumps 50A and 50B to a certain level or more. I can't let you.

  On the other hand, in the reciprocating pump 50C, the speed of the boosting piston 52C can be increased without being affected by the discharge of the other reciprocating pumps 50A and 50B, and the discharge time is lengthened to shorten the suction time. The total discharge amount can be increased. Therefore, the total discharge amount of the reciprocating pumps 50A, 50B, 50C can be varied according to the amount of fuel required by the internal combustion engine 90. Here, in the linear actuator 30B that drives the reciprocating pump 50C, it is preferable to use a servo motor as the electric motor 32B from the viewpoint that the response speed is fast and fine position control of the boosting piston 52C can be performed. However, an inverter motor may be used as the electric motor 32B if a sufficient response speed can be obtained.

  For example, the controller 21 controls the linear actuator 30B so that the acceleration of the boosting piston 52C when the reciprocating pump 50C sucks fuel is smaller than the acceleration when the boosting piston 52C performs a single vibration motion. . Here, when the boosting piston 52C performs a single vibration motion, it reciprocates at a constant cycle and a constant amplitude.

The solid line in FIG. 5 is a diagram showing an example of the time variation of the speed of the boosting piston 52C in this embodiment, where the horizontal axis is time, the vertical axis is speed, and the speed of the boosting piston 52C during discharge is positive. Yes. That is, the reciprocating pump 50 discharges fuel from time t0 to t1 when the piston speed is positive, and the reciprocating pump 50 sucks fuel from time t1 to t4 when the piston speed is negative. Note that the times t0 to t4 shown in FIG. 5 are different from the times t0 to t6 shown in FIG.
Also, the alternate long and short dash line in FIG. 5 is the time variation of the speed of the boosting piston when the boosting piston 52C performs a single vibration motion. Even when the boosting piston 52C is oscillated, the reciprocating pump 50C discharges fuel from the time t0 to t1 when the piston speed is positive, and the reciprocating pump 50C from time t1 to t4 when the piston speed is negative. Inhales fuel.
For comparison, the period and stroke are the same in the case of this embodiment (solid line) and in the case of simple vibration (one-dot chain line). That is, the integral value of the speed from time t0 to t1 (during discharge) is the same in the case of this embodiment (solid line) and in the case of simple vibration (one-dot chain line). Similarly, the integral value of the velocity from time t1 to time t4 (during inhalation) is the same in the case of this embodiment (solid line) and in the case of simple vibration (dashed line).

  The solid line in FIG. 5 accelerates the boosting piston 52C from the start of suction (t1) to t2, and moves the pressurization piston 52 at a constant speed from t2 to t3. The pressure increasing piston 52C is decelerated until (t4). Here, “accelerate” means to increase the absolute value of the speed of the boosting piston 52C, and “decelerate” means to decrease the absolute value of the speed of the boosting piston 52.

In the solid line in FIG. 5, the acceleration of the boosting piston 52 may become the maximum acceleration during inhalation between t1 and t2. This maximum acceleration is the maximum absolute value of the gradient from t1 to t2 of the solid line in FIG.
On the other hand, when the boosting piston makes a single vibration (dashed line), the maximum acceleration of the boosting piston 52 is at the start of inhalation (t1), and the maximum acceleration is the absolute slope of the dashed line at t1 in FIG. Value.

  As shown by the solid line in FIG. 5, in the present embodiment, the maximum acceleration (maximum absolute value of the inclination from the solid line t1 to t2) of the boosting piston 52 at the time of inhalation is the maximum acceleration ( The linear actuator 30B is controlled so as to be smaller than the absolute value of the inclination at t1 of the alternate long and short dash line. For this reason, it is possible to prevent the pressure in the boosting cylinder 51C from rapidly decreasing and to suppress the occurrence of cavitation.

  In the case of simple vibration, the maximum acceleration is at the start of inhalation (t1). However, in this embodiment, it is necessary to control the speed of the boosting piston 52C so that the inhalation start is at the maximum acceleration. Absent. For example, the time when the acceleration of the boosting piston 52C is maximized is after the fuel inhalation start time (t1) and before the time ¼ of one cycle has elapsed from the inhalation start time (t1). You may control so that it may become.

The stroke length of the boosting piston 52C is a moving distance from the position where the volume in the reciprocating pump 50C is minimized to the position where the volume is increased when the boosting piston 52C reciprocates. Since the linear actuator 30B drives the boosting piston 52C, the stroke length of the boosting piston 52C can be arbitrarily set.
The stroke length is set with reference to the position where the volume in the reciprocating pump 50C is minimized. Regardless of how the stroke length is set by adjusting the stroke length with reference to this position, the liquid fuel in the reciprocating pump 50C is completely discharged in each cycle.

  The solid line in FIG. 6 is a diagram showing another example of the time variation of the speed of the boosting piston 52C in the present embodiment, where the horizontal axis is time and the vertical axis is speed, and the speed of the boosting piston 52C during discharge is shown. It is positive. That is, the reciprocating pump 50C discharges fuel from time t0 to t1 when the piston speed is positive, and the reciprocating pump 50C sucks fuel from time t1 to t5 when the piston speed is negative. 6 are different from the times t0 to t6 shown in FIG. 4 and the times t0 to t4 shown in FIG.

6 is the time variation of the speed of the boosting piston 52C when the boosting piston 52C performs a single vibration motion. When the boosting piston 52C performs a single oscillation motion (dashed line), the reciprocating pump 50C discharges fuel from time t0 to t2 when the piston speed is positive, and reciprocates from time t2 to t5 when the piston speed is negative. The pump 50C sucks fuel.
For comparison, the period and stroke are the same in the case of this embodiment (solid line) and in the case of simple vibration (one-dot chain line). That is, the integrated value of the velocity from the time t0 to t1 (during discharge) in the case of the present embodiment (during discharge) is the integrated value of the velocity from the time t0 to t2 in the case of simple vibration (dash line) (during discharge). Is the same. Similarly, in the case of this embodiment (solid line), the integral value of speed from time t1 to time t5 (during suction) is the integral of speed from time t2 to time t5 in the case of simple vibration (dash chain line) (during suction). Is the same as the value.

  The solid line in FIG. 6 accelerates the boosting piston 52C from the start of suction (t1) to t3, moves the pressurization piston 52C at a constant speed from t3 to t4, and ends the suction from t4. The pressure increasing piston 52C is decelerated until (t5).

In the solid line in FIG. 6, the acceleration of the boosting piston 52C may become the maximum acceleration during inhalation between t1 and t3. This maximum acceleration is the maximum absolute value of the gradient from t1 to t3 of the solid line in FIG.
On the other hand, in the case where the boosting piston 52C is oscillated (one-dot chain line), when the acceleration of the boosting piston 52C becomes maximum, the suction starts (t2), and the maximum acceleration is the slope at t2 of the one-dot chain line in FIG. Absolute value.

  As shown in FIG. 6, even when the boosting piston 52C is controlled, the maximum acceleration when the maximum acceleration of the boosting piston 52C during suction (the maximum absolute value of the slope of the solid line from t1 to t3) is a single vibration. The linear actuator 30B is controlled so as to be smaller than (the absolute value of the inclination at t2 of the alternate long and short dash line). For this reason, it is possible to prevent the pressure in the boosting cylinder 51C from rapidly decreasing and to suppress the occurrence of cavitation.

  In the case of FIG. 5, the fuel discharge period (between t0 and t1) and the fuel intake period (t1 to t4) in one cycle (time from t0 to t4) of the boosting piston 52C. Between) is equal. On the other hand, in the case of FIG. 6, the period (t1) during which the fuel is sucked rather than the period during which the fuel is discharged (between t0 and t1) in one cycle (time from t0 to t5) of the boosting piston 52. To t5) is longer.

For this reason, the period (between t1 and t3 in FIG. 6) of accelerating the boosting piston 52C at the time of inhalation can be made longer, and the maximum acceleration can be further reduced.
Further, as shown in FIG. 6, the period of time during which fuel is sucked (between t1 and t5) is made longer than the period during which fuel is discharged (between t0 and t1). The speed (absolute value of speed between t3 and t4 of the solid line) can be made smaller than in the case of simple vibration. For this reason, the maximum value of acceleration for accelerating to the maximum speed can be reduced.

  In the above embodiment, the case where the time for sucking fuel is the same as the time for discharging fuel (FIG. 5), and the case where the time for sucking fuel is longer than the time for discharging fuel (FIG. 6) have been described. The time for inhaling the fuel may be shorter than the time for discharging the fuel.

  In addition, since the plurality of reciprocating pumps 50A, 50B, 50C are provided in parallel between the low pressure fuel supply pipe 12 and the high pressure fuel supply pipe 13, the number of reciprocating pumps can be easily changed. Moreover, even when trouble occurs in any of the plurality of reciprocating pumps or when maintenance is performed, any of the reciprocating pumps can be removed and the other reciprocating pumps can continue to be driven.

  Further, since the reciprocating pump 50C can be controlled independently of the other reciprocating pumps 50A and 50B, the amount of fuel supplied can be changed according to the fuel demand of the internal combustion engine 90. Further, since the operation of the boosting piston 52C of the reciprocating pump 50C is not restricted by the other reciprocating pumps 50A and 50B, the piston stroke can be freely adjusted. For this reason, the discharge amount of the reciprocating pump 50C can be adjusted independently of the other reciprocating pumps 50A and 50B.

  Further, by using an inverter motor for the linear actuator 30A that drives the reciprocating pumps 50A and 50B, the apparatus can be made cheaper than when a servo motor is used.

  In addition, by providing a position sensor that detects the positions of the boosting pistons 52A, 52B, and 52C, the speed and position of the boosting pistons 52A, 52B, and 52C can be reliably adjusted.

  In the above description, the case where three reciprocating pumps 50A, 50B, and 50C 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. The shape of the reciprocating pumps 50A, 50B, 50C is not limited to the shape shown in FIGS. 2 and 3, and a reciprocating pump having an arbitrary shape can be used.

[Second Embodiment]
FIG. 7 is a schematic configuration diagram of a fuel supply apparatus 10B according to the second embodiment. The fuel supply device 10B of the present embodiment is different from the fuel supply device 10A of the first embodiment in the configuration of the fuel supply unit 20B. Since the configuration other than the fuel supply unit 20B is the same as that of the first embodiment, the description is omitted.

In addition to the configuration of the fuel supply unit 20A of the first embodiment, the fuel supply unit 20B of the present embodiment further includes a linear actuator 30C and reciprocating pumps 50D and 50E.
FIG. 8 is a cross-sectional view of the linear actuator 30C and the reciprocating pumps 50D and 50E. The configuration of the linear actuator 30C is the same as the configuration of the linear actuator 30A of the first embodiment. For this reason, about the structure of 30 C of linear actuators, the code | symbol of a different character with the same number as the structure of the linear actuator 30A is attached | subjected, and description is omitted.
The configurations of the reciprocating pumps 50D and 50E are the same as the configurations of the reciprocating pumps 50A and 50B of the first embodiment. For this reason, about the structure of reciprocating pump 50D, 50E, the code | symbol of a different character with the same number as the structure of reciprocating pump 50A, 50B is attached | subjected, and description is omitted. The other configuration of the fuel supply unit 20B is the same as the configuration of the fuel supply unit 20A of the first embodiment, and a description thereof will be omitted.

  In this embodiment, since the linear actuator 30C and the reciprocating pumps 50D and 50E are provided in addition to the linear actuator 30A and the reciprocating pumps 50A and 50B, the phase of the reciprocating motion of the linear actuator 30A and By shifting the phase of the reciprocating motion of the linear actuator 30C, pulsation can be reduced.

  FIG. 9A is a diagram showing an example of time variation of the total discharge amount of the reciprocating pumps 50A and 50B, and FIG. 9B is a time variation of the total discharge amount of the reciprocating pumps 50D and 50E. FIG. 9C is a diagram showing an example of time variation of the total discharge amount of the reciprocating pumps 50A, 50B, 50D, and 50E, and FIG. 9D is a diagram showing the reciprocating pump. It is a figure which shows an example of the time fluctuation | variation of the discharge amount of 50C, FIG.9 (e) is a figure which shows an example of the time fluctuation | variation of the total amount of the discharge amount of reciprocating pump 50A, 50B, 50C, 50D, 50E. FIG. 9 is an example of time fluctuation when the output of the internal combustion engine 90 is constant.

Since the reciprocating pumps 50A and 50B are provided at both ends of the same linear actuator 30A, the discharge from the reciprocating pump 50A and the discharge from the reciprocating pump 50B are performed alternately, and the reciprocating pumps 50A and 50B The total amount of discharge varies as shown in FIG. In FIG. 9A, the discharge amount from the reciprocating pump 50A increases from time t0 to t1, the discharge amount from the reciprocating pump 50A from time t1 to t5 is constant (v), and the time The discharge amount from the reciprocating pump 50A decreases between t5 and t6. The discharge amount from the reciprocating pump 50A between the times t6 and t12 is zero.
On the other hand, the discharge amount from the reciprocating pump 50B between the times t0 and t6 is zero. The discharge amount from the reciprocating pump 50B increases from time t6 to t7, the discharge amount from the reciprocating pump 50B from time t7 to t11 is constant (v), and the reciprocation from time t11 to t12 The discharge amount from the pump 50B decreases.

Since the reciprocating pumps 50D and 50E are provided at both ends of the same linear actuator 30C, the discharge from the reciprocating pump 50D and the discharge from the reciprocating pump 50E are performed alternately, and the reciprocating pumps 50D and 50E The total discharge amount varies as shown in FIG. Here, the reciprocating motion of the linear actuator 30C is shifted from the reciprocating motion of the linear actuator 30A by ¼ period. In FIG. 9B, the discharge amount of the reciprocating pump 50D is constant (v) from time t0 to t2, and the discharge amount from the reciprocating pump 50D decreases from time t2 to t3. The discharge amount from the reciprocating pump 50D between the times t3 and t9 is zero. The discharge amount from the reciprocating pump 50D increases from time t9 to t10, and the discharge amount from the reciprocating pump 50D from time t10 to t12 is constant (v).
On the other hand, the discharge amount of the reciprocating pump 50E is zero between the times t0 and t3. The discharge amount from the reciprocating pump 50E increases from time t3 to t4, the discharge amount from the reciprocating pump 50E from time t4 to t8 is constant (v), and the reciprocation from time t8 to t9. The discharge amount from the pump 50E decreases. The discharge amount of the reciprocating pump 50E between time t9 and t12 is zero.

  For this reason, the time fluctuation of the total discharge amount of the reciprocating pumps 50A, 50B, 50D, and 50E is as shown in FIG. Here, when the reciprocating motion of the linear actuator 30C is deviated from the reciprocating motion of the linear actuator 30A by ¼ cycle, the total discharge amount of the reciprocating pumps 50A and 50B is smaller than the maximum discharge amount (v). (T0 to t1, t5 to t7, t11 to t12) and when the total discharge amount of the reciprocating pumps 50D and 50E is smaller than the maximum discharge amount (v) (t2 to t4, t8 to t10). Since they do not overlap, the maximum fluctuation amount of the total discharge amount of the reciprocating pumps 50A, 50B, 50D, and 50E is v. For this reason, the change amount can be halved with respect to the maximum value (2v) of the total discharge amount of the reciprocating pumps 50A, 50B, 50D, and 50E.

In the present embodiment, when the output of the internal combustion engine 90 is constant, the total of the fuel discharge speeds (the fuel discharge amount per unit time) discharged from each of the reciprocating pumps 50A to 50E is constant. In addition, it is preferable that the controller 21 adjusts the driving of the linear actuator 30B.
As shown in FIG. 9 (c), the total discharge amount of the reciprocating pumps 50A, 50B, 50D, and 50E becomes smaller than the maximum value (2v) when the time t0 to t1, t2 to t4, and t5. It is between t7, t8 to t10, and t11 to t12. Therefore, in the present embodiment, as shown in FIG. 9D, the total amount of the discharge amounts of the reciprocating pumps 50A, 50B, 50D, and 50E is compensated for the difference amount reduced from the maximum value (2v). The discharge amount of the reciprocating pump 50C is adjusted. As a result, as shown in FIG. 9E, the total discharge amount of the reciprocating pumps 50A, 50B, 50C, 50D, and 50E can be set to a constant value (2v). That is, in the fuel supply unit 20B of the second embodiment, the maximum fuel discharge amount (2v) can be set to be twice the maximum fuel discharge amount (v) of the fuel supply unit 20A of the first embodiment. Further, by adding a unit similar to the unit including the linear actuator 30C and the reciprocating pumps 50D and 50E, the maximum fuel discharge amount can be further increased.
On the other hand, even if one of the units consisting of the linear actuator 30A and the reciprocating pumps 50A and 50B and the unit consisting of the linear actuator 30C and the reciprocating pumps 50D and 50E fails, the failed unit is removed and replaced and repaired. The operation rate can be increased because only the remaining units can be operated as in the first embodiment.

  Further, by using an inverter motor for the linear actuators 30A, 30C for driving the reciprocating pumps 50A, 50B, 50D, 50E, the apparatus can be made cheaper than when a servo motor is used.

  FIG. 10A is a diagram showing another example of the time variation of the total discharge amount of the reciprocating pumps 50A and 50B, and FIG. 10B is a graph showing the total discharge amount of the reciprocating pumps 50D and 50E. FIG. 10C is a diagram showing another example of time variation, and FIG. 10C is a diagram showing another example of time variation of the total discharge amount of the reciprocating pumps 50A, 50B, 50D, and 50E. FIG. 10D is a diagram showing another example of the time variation of the discharge amount of the reciprocating pump 50C, and FIG. 10E is the time variation of the total discharge amount of the reciprocating pumps 50A, 50B, 50C, 50D, and 50E. It is a figure which shows another example of.

In FIG. 10A, the total discharge amount of the reciprocating pumps 50A and 50B varies in the same manner as in FIG.
In FIG. 10B, the discharge amount of the reciprocating pump 50C is constant (v) from time t0 to t4, and the discharge amount from the reciprocating pump 50C decreases from time t4 to t5. The discharge amount from the reciprocating pump 50C between the times t5 and t11 is zero. The discharge amount from the reciprocating pump 50C increases from time t11 to t12.
On the other hand, the discharge amount of the reciprocating pump 50E is zero between times t0 and t4. The discharge amount from the reciprocating pump 50E increases from time t4 to t5, the discharge amount from the reciprocating pump 50E from time t5 to t10 is constant (v), and the reciprocation from time t10 to t11 The discharge amount from the pump 50E decreases. The discharge amount of the reciprocating pump 50E between time t11 and t12 is zero.

  For this reason, the time fluctuation of the total discharge amount of the reciprocating pumps 50A, 50B, 50D, and 50E is as shown in FIG. Here, when the total discharge amount of the reciprocating pumps 50A and 50B decreases (from time t5 to t6 and from time t11 to t12), the total discharge amount of the reciprocating pumps 50D and 50E increases. The linear actuators 30A and 30C are controlled so that the decreasing speed of the total discharge amount of the reciprocating pumps 50A and 50B is equal to the increasing speed of the total discharge amount of the reciprocating pumps 50D and 50E. . Therefore, the total discharge amount of the reciprocating pumps 50A, 50B, 50D, and 50E is constant (v) between time t5 and t6 and between time t11 and t12.

  As shown in FIG. 10 (c), the total discharge amount of the reciprocating pumps 50A, 50B, 50D, and 50E becomes smaller than the maximum value (2v) when the time t0 to t1, t4 to t7, and t10. Between t12. Therefore, in the present embodiment, as shown in FIG. 10 (d), the total amount of the discharge amounts of the reciprocating pumps 50A, 50B, 50D, and 50E is compensated for the difference amount reduced from the maximum value (2v). The discharge amount of the reciprocating pump 50C is adjusted. Thereby, as shown in FIG.10 (e), the total amount of discharge amount of reciprocating pump 50A, 50B, 50C, 50D, 50E can be made into a fixed value (2v).

  In the case of FIG. 9, the boosting piston 52C of the reciprocating pump 50C reciprocates four times while the boosting pistons 52A, 52B, 52D, 52E of the reciprocating pumps 50A, 50B, 50D, 50E reciprocate once. There is a need. On the other hand, in the case of FIG. 10, the boosting piston 52C only needs to reciprocate twice while the boosting pistons 52A, 52B, 52D, and 52E reciprocate once. For this reason, in the case of FIG. 10, since the response speed required for the hydraulic pump 33B used for the linear actuator 30B for operating the reciprocating pump 50C is lower, a hydraulic pump having a lower response speed can be used.

  In FIG. 10, when the total discharge amount of the reciprocating pumps 50A and 50B decreases (between time t5 and t6 and between time t11 and t12), the total discharge amount of the reciprocating pumps 50D and 50E. The linear actuators 30A and 30C are controlled so that the rate of increase in the total amount of discharge from the reciprocating pumps 50A and 50B is equal to the rate of increase in the total amount of discharge from the reciprocating pumps 50D and 50E. However, the present invention is not limited to this. For example, when the total discharge amount of the reciprocating pumps 50A and 50B increases, the total discharge amount of the reciprocating pumps 50D and 50E decreases, and the total discharge amount of the reciprocating pumps 50A and 50B increases. The linear actuators 30A and 30C may be controlled so that the speed and the reduction speed of the total amount of the discharge amounts of the reciprocating pumps 50D and 50E are equal.

  In the above embodiment, the maximum discharge amount (v) by the reciprocating pumps 50A and 50B and the reciprocating pumps 50D and 50E is the same, but the present invention is not limited to this. For example, the maximum discharge amount by the reciprocating pumps 50D and 50E may be several times the maximum discharge amount by the reciprocating pumps 50A and 50B.

  In the above embodiment, the case where the boosting cylinders 51A, 51B, 51C, 51D, 51E of the reciprocating pumps 50A, 50B, 50C, 50D, 50E are driven in the horizontal direction has been described. However, the boosting cylinders 51A, 51B, 51C, 51D, and 51E may be driven in the vertical direction.

10A, 10B Fuel supply device 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 regulating valve 17 Pressure gauge 20A, 20B Fuel supply unit 21 Controller 30A, 30B Linear actuator 31A Inverter 31B Servo amplifiers 32A, 32B Electric motors 33A, 33B Hydraulic pumps 34A, 34B First hydraulic pipes 35A, 35B Second hydraulic pipes 41A, 41B Hydraulic cylinders 42A, 42B Hydraulic pistons 43A, 43B Hydraulic oil containing space 43a First chamber 43b 2nd chamber 47A, 47B, 47C, 47D Piston rod 49A, 49B, 49C Connection part 50A (1st) reciprocating pump 50B (2nd) reciprocating pump 50C (3rd) reciprocating pump 50D (4th) reciprocating Type pump 50E (5th Reciprocating pumps 51A, 51B, 51C, 51D, 51E Boosting cylinders 52A, 52B, 52C, 52D, 52E Boosting pistons 53A, 53B, 53C, 53D, 53E Cylinder liners 54A, 54B, 54C, 54D, 54E Covers 55A, 55B, 55C, 55D, 55E Suction port 56A, 56B, 56C, 56D, 56E Discharge port 60A, 60B, 60C, 60D, 60E Valve box 61A, 61B, 61C, 61D, 61E Discharge flow path 62A, 62B, 62C, 62D 62E Discharge check valves 64A, 64B, 65C, 65D, 65E Suction flow paths 65A, 65B, 65C, 65D, 65E Suction check valves 70A, 70B, 70D Position sensor 80 Control unit 90 Internal combustion engine

Claims (7)

A fuel supply device for supplying liquefied fuel into a combustion chamber of an internal combustion engine,
A first reciprocating pump having a first boosting piston that reciprocates in the axial direction, and alternately sucking and discharging the liquefied fuel by reciprocating the first boosting piston in the axial direction;
A second reciprocating pump that has a second boosting piston that reciprocates in the axial direction, and alternately sucks and discharges the liquefied fuel by reciprocating the second boosting piston in the axial direction;
The first boosting piston and the second boosting piston are attached so as to be coaxial, and the first reciprocating pump and the first boosting piston are reciprocated in the axial direction by reciprocating the first boosting piston and the second boosting piston. A first linear actuator that causes the second reciprocating pump to alternately discharge the liquefied fuel;
A third reciprocating pump having a third boosting piston that reciprocates in the axial direction, and alternately sucking and discharging the liquefied fuel by reciprocating the third boosting piston in the axial direction;
A second linear actuator for reciprocating the third boosting piston in the axial direction;
A controller for controlling driving of the first linear actuator and the second linear actuator ,
The controller determines an absolute value of a maximum acceleration for accelerating a moving speed of the third boosting piston in the suction movement direction when the third reciprocating pump sucks the liquefied fuel. A fuel supply for controlling the third reciprocating pump so as to reduce the speed of movement of the third booster piston in the discharge movement direction when discharging the liquefied fuel to be smaller than the absolute value of the maximum acceleration for accelerating; apparatus. A fourth reciprocating pump having a fourth boosting piston that reciprocates in the axial direction and alternately sucking and discharging the liquefied fuel by reciprocating the fourth boosting piston in the axial direction;
A fifth reciprocating pump having a fifth boosting piston that reciprocates in the axial direction, and alternately sucking and discharging the liquefied fuel by reciprocating the fifth boosting piston in the axial direction;
The fourth boosting piston and the fifth boosting piston are mounted so as to be coaxial, and the fourth boosting piston and the fifth boosting piston are reciprocated in the axial direction, thereby allowing the fourth reciprocating pump and A third linear actuator that causes the fifth reciprocating pump to alternately discharge the liquefied fuel ,
The controller controls driving of the third linear actuator in addition to the first linear actuator and the second linear actuator;
The fuel supply device according to claim 1. In the case where the output of the internal combustion engine is constant, the controller
The drive of the second linear actuator is adjusted so that the total discharge speed of the liquefied fuel discharged from each of the first reciprocating pump, the second reciprocating pump, and the third reciprocating pump is constant. The fuel supply device according to claim 1. In the case where the output of the internal combustion engine is constant, the controller
The sum of the discharge speeds of the liquefied fuel discharged from each of the first reciprocating pump, the second reciprocating pump, the third reciprocating pump, the fourth reciprocating pump, and the fifth reciprocating pump is constant. The fuel supply device according to claim 2, wherein the driving of the second linear actuator is adjusted so that   The controller has a maximum speed in the reciprocating motion of the fourth pressure increasing piston and the fifth pressure increasing piston when the speed in the reciprocating motion of the first pressure increasing piston and the second pressure increasing piston is minimum, And when the speed in the reciprocating motion of the first boosting piston and the second boosting piston is maximized, the speed in the reciprocating motion of the fourth boosting piston and the fifth boosting piston is minimized. The fuel supply device according to claim 2, wherein the first linear actuator and the third linear actuator are controlled. The controller is configured to make the suction time when the third reciprocating pump sucks the liquefied fuel longer than the discharge time when the third reciprocating pump discharges the liquefied fuel. The fuel supply apparatus of any one of Claims 1-5 which controls 3 reciprocating pumps. The controller controls the driving of the third reciprocating pump so that the third boosting piston reciprocates a predetermined moving distance at a predetermined cycle;
When the third reciprocating pump sucks the liquefied fuel, the absolute value of the maximum acceleration for accelerating the moving speed of the third boosting piston in the suction movement direction is determined by the third boosting piston at the predetermined cycle. Thus, when the liquefied fuel is sucked by reciprocating the predetermined moving distance by a simple vibration motion, the absolute value of the maximum acceleration for accelerating the moving speed of the third boosting piston in the suction moving direction is small. The fuel supply apparatus of any one of Claims 1-6.

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