JP5903766B2 - Fuel supply device - Google Patents

Description

  The present invention relates to a fuel supply apparatus.

  In general, a fuel supply device is attached to a jet engine (turbofan engine) used in an aircraft or the like. The fuel supply device includes, for example, a fuel pump, a metering unit, and a fuel cooler. The fuel pump sends the fuel from the fuel tank to the metering unit. Based on the measurement result of the metering unit, excess fuel relative to the required amount is returned upstream of the fuel pump. The required amount of fuel is supplied to the engine combustor after being cooled by the fuel cooler.

  A gear pump is known as an example of the fuel pump. The gear pump includes a gear and a casing. The fuel flowing into the gear pump is confined in a space surrounded by the gear and the inner wall surface of the casing and is carried downstream. Conventional gear pumps are often driven by rotational movement transmitted from a jet engine. In this configuration, the discharge amount of the gear pump is substantially proportional to the engine speed.

  By the way, the fuel consumption in the engine combustor is not proportional to the engine speed, for example, depending on the operating state of the jet engine such as the flight altitude. For example, during cruising, the required thrust is reduced more than during takeoff or the like, so that the required amount of fuel is reduced, and the amount of fuel returned to the upstream of the gear pump is increased. Then, the energy required for the circulation of the fuel increases, so the temperature of the fuel rises and the load on the fuel cooler may increase.

  From such a viewpoint, in recent years, a technique has been proposed in which the discharge amount of the gear pump can be switched under the same engine speed. For example, a triple gear pump disclosed in Patent Document 1 includes two driven gears arranged to face each other with a drive gear interposed therebetween. Each driven gear and the inner wall surface of the casing function as one pump unit.

  Thus, the triple gear pump has a structure including two pump parts, and the connection relation of the two pump parts can be switched in parallel or in series. For example, when the rotational speeds of the drive gears are compared under the same conditions, the discharge amount when the two gear pumps are connected in series is about half the discharge amount when the gear pumps are connected in parallel.

JP 2003-328958 A

  By the way, the technique which controls the discharge amount of a gear pump by driving with a servomotor etc. instead of driving a drive gear with the rotational motion from a jet engine is considered. According to this technique, the discharge amount of the gear pump can be set arbitrarily, and the necessity of circulating excess fuel is reduced. On the other hand, in this technology, if it is possible to cope with a rapid change in the discharge amount with high accuracy, for example, the power supply source to the servo motor becomes large due to a transient increase in pump load. There are challenges.

  An object of the present invention is to provide a fuel supply device that can reduce a surplus of a discharge amount of a pump and can cope with a change in a discharge amount with high accuracy even though the present invention has been made in view of the above circumstances. One of them.

  The fuel supply device of the present invention includes a first pump unit that flows fuel by rotation of a first gear, a second pump unit that flows fuel by rotation of a second gear, the first pump unit, and the A metering unit for metering the flow rate of the fuel from the second pump unit; a bypass metering valve for regulating the flow rate of the fuel flowing from the second pump unit to the metering unit; and the first gear. And a control unit that controls the drive unit to adjust the rotational speed of the first gear and controls the adjustment amount of the fuel flow rate by the bypass metering valve.

  In this way, the control unit controls the rotation speed of the first gear and the adjustment amount of the bypass metering valve, so that the discharge amounts of the first pump unit and the second pump unit can be accurately controlled. It is possible to control in response to a sudden change, and it becomes possible to reduce the surplus of the discharge amount of the pump and to reduce the load on the servo motor. Further, since the control of the fuel flow rate is divided into the control of the rotation speed of the first gear and the control of the adjustment amount of the bypass metering valve, it is possible to cope with the change in the discharge amount with high accuracy.

In the fuel supply apparatus, the driving unit includes a driving gear meshed with the first gear and the second gear, and the first gear and the second gear via the driving gear . The gear may be driven.

  In this way, the first gear can be rotationally driven by the same motor as the second gear via the driving gear, and the second gear can be driven by a motor different from the motor that rotates the first gear. The number of motors can be reduced as compared with the rotating configuration.

  In the fuel supply apparatus, the drive unit may be a motor.

  In this way, the rotation speed of the first gear can be controlled to an arbitrary value.

  In the fuel supply apparatus, a frequency at which the control unit controls the drive unit may be lower than a frequency at which the control unit controls the bypass metering valve.

  If it does in this way, the load at the time of changing the rotation speed of a motor can be reduced, and the motor and the electric power supply source to a motor can be reduced in size.

  The fuel supply device includes a bypass passage for returning the fuel discharged from the second pump unit to the upstream side of the second pump unit, and the fuel discharged from the second pump unit to the first A discharge passage that merges with the fuel discharged from one pump unit, the metering unit is disposed downstream of the fuel via the discharge passage, and the bypass metering valve is connected to the bypass flow It may be arranged on the road.

  In this way, the fuel discharged from the second pump unit and passing through the discharge flow path merges with the fuel discharged from the first pump unit and flows into the metering unit, and the first pump unit and The fuel discharged from the second pump unit can flow to the metering unit. In addition, since the fuel that has passed through the bypass flow path returns to the upstream side of the second pump section, the bypass metering valve adjusts the flow rate of the fuel that passes through the bypass flow path, so that the fuel flow to the metering section via the discharge flow path. The flow rate of the inflowing fuel can be adjusted.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to reduce the excess of the discharge amount of a pump, the fuel supply apparatus which can respond to a sudden change of discharge amount with high precision can be provided.

It is a schematic structure figure showing an example of a propulsion system to which the present invention is applied. It is explanatory drawing which shows the structural example of the fuel supply apparatus to which this invention is applied. It is a graph which shows an example of the discharge amount of a triple gear pump.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The technical scope of the present invention is not limited to the following embodiments, and various modifications can be made without departing from the spirit of the present invention.

  FIG. 1 is a schematic configuration diagram showing an example of a propulsion system to which the present invention is applied. FIG. 2 is an explanatory view showing a configuration example of a fuel supply apparatus to which the present invention is applied. A propulsion system S shown in FIG. 1 includes a fuel supply device 1 and a jet engine 2. The fuel supply device 1 includes a fuel tank 3, a centrifugal pump 4, a gear pump 5, a servo motor 6, a flow rate switching unit 7, a metering unit 8, a fuel cooler 9, and a control unit 10. The jet engine 2 includes an engine combustor 11 and a fan 12. The propulsion system S generally operates as follows.

  The fuel Q stored in the fuel tank 3 is boosted by the centrifugal pump 4 and supplied to the gear pump 5. The gear pump 5 is constituted by a triple gear pump, for example, and includes two pump parts. The flow rate switching unit 7 adjusts the discharge amount of the gear pump 5 by switching the connection relationship between the two pump units of the gear pump 5. The gear pump 5 is driven by the servo motor 6 to send the fuel Q to the fuel cooler 9. The metering unit 8 is provided in a flow path between the gear pump 5 and the fuel cooler 9 and measures the flow rate of the fuel Q flowing to the fuel cooler 9. The measurement result of the weighing unit 8 is output to the control unit 10. The fuel Q is cooled by exchanging heat with the lubricating oil R in the fuel cooler 9. The lubricating oil R is supplied to the fuel cooler 9 from a lubricating system (not shown). The fuel Q cooled by the fuel cooler 9 is supplied to the engine combustor 11 of the jet engine 2.

  In addition, when the flow rate of the fuel Q measured by the metering unit 8 is larger than the necessary amount, a configuration in which excess fuel is returned upstream from the gear pump 5 may be employed. For example, the passage between the gear pump 5 and the fuel tank 3 and the gap between the gear pump 5 and the fuel cooler 9 are connected to flow excess fuel.

  In addition to the fuel Q, compressed air or the like is supplied to the engine combustor 11. Combustion gas is generated when the fuel Q is mixed with compressed air and combusted. This combustion gas is injected (exhaust) downstream, and a thrust is generated by the reaction. The combustion gas is exhausted and rotates the fan 12. The rotational power of the fan 12 is used for intake or compression of the air that becomes the compressed air. The rotational speed of the fan 12 is output to the control unit 10.

  The control unit 10 receives the measurement result of the metering unit 8 and the rotational speed of the fan 12 and controls the servo motor 6 and the flow rate switching unit 7 to control the discharge amount of the fuel Q from the gear pump 5. For example, in the propulsion system S mounted on an aircraft or the like, information such as the rotation speed of the fan 12 is displayed on the operation panel and transmitted to the operator. When the operator operates, for example, the throttle lever, the discharge amount of the gear pump 5 is controlled according to the amount of fuel necessary to obtain a given thrust according to the input of the operator.

Next, the fuel supply apparatus according to this embodiment will be described in detail.
As shown in FIG. 2, in this embodiment, the relief valve 13 and the fuel supply cutoff valve 14 are connected in parallel with the flow path of the fuel Q that passes through the gear pump 5. Specifically, the relief valve 13 is provided in a flow path that connects between the gear pump 5 and the metering unit 8 and between the gear pump 5 and the centrifugal pump 4. The fuel supply cutoff valve 14 is connected in the same manner as the relief valve 13, and is connected in parallel with the relief valve 13 and in parallel with the gear pump 5.

  The relief valve 13 functions as a check valve when the pressure between the gear pump 5 and the metering unit 8 is a predetermined value or less, and functions as an open valve when the pressure exceeds a predetermined value. For example, the relief valve 13 can prevent this pressure from exceeding the pressure resistance of the system when the pressure in the flow path rises due to foreign matters mixed into the flow path.

  The fuel supply cutoff valve 14 is a valve for shutting off the fuel supply to the jet engine 2. The fuel supply shut-off valve 14 is actuated by, for example, an operator's command or the like, and opens the flow path between the gear pump 5 and the metering unit 8 with respect to the flow path between the gear pump 5 and the centrifugal pump 4. When the fuel supply shut-off valve 14 is in the open state, the pressure of the fuel Q is almost the same (the differential pressure is almost 0) before and after passing through the gear pump 5, and the flow rate of the fuel Q passing through the measuring unit 8 becomes almost zero. For example, when the servo motor 6 becomes uncontrollable due to unforeseen reasons, the fuel supply to the jet engine 2 can be shut off by the fuel supply shut-off valve 14.

  The gear pump 5 includes a casing 15, a driving gear 16, a first gear 17, and a second gear 18. The gears 16 to 18 are accommodated in the casing 15 while being engaged with each other. The gears 16 to 18 are rotatably supported by bearings such as journal bearings. The first gear 17 and the second gear 18 are disposed to face each other with the driving gear 16 in between. In the following description, the direction in which the first gear 17 and the second gear 18 face each other is referred to as the gear facing direction. The servo motor 6 is connected to the driving gear 16. The servo motor 6 is a motor whose rotational speed can be controlled by the control unit 10.

  The drive gear 16 is rotated by the torque supplied from the servo motor 6. The first gear 17 and the second gear 18 are driven gears that rotate by meshing with the driving gear 16. That is, the servo motor 6 rotationally drives the first gear 17 via the driving gear 16.

  In the present embodiment, the first gear 17 and the second gear 18 have the same size, shape, and number of teeth. The drive gear 16 may have the same size, shape, or number of teeth as the first gear 17 and the second gear 18, or may be different. As a tooth profile of the gears 16 to 18, an involute tooth profile can be preferably used, but a sinusoidal tooth profile or a trochoidal curve tooth profile may be used.

  The fuel Q is confined in a space surrounded by each of the gears 16 to 18 and the inner wall surface of the casing 15 and is carried downstream. The first pump unit 19 is configured to include almost half of the driving gear 16 on the first gear 17 side in the gear facing direction. Similarly, the second pump unit 20 is configured to include almost half of the driving gear 16 on the second gear 18 side in the gear facing direction.

  Each of the 1st pump part 19 and the 2nd pump part 20 functions similarly to a double gear pump. The double gear pump is a pump composed of a casing and two gears. The total amount of substantial discharge amounts of the first pump unit 19 and the second pump unit 20 becomes the discharge amount of the gear pump 5.

  The fuel Q from the centrifugal pump 4 is supplied to the first pump unit 19 from a direction that intersects with the first pump unit 19 in the gear facing direction. When the driving gear 16 and the first gear 17 rotate, the fuel Q is pressurized by the first pump unit 19 and discharged downstream. The flow path and discharge amount of the fuel Q that passes through the second pump unit 20 will be described together with the configuration of the flow rate switching unit 7.

  The flow rate switching unit 7 of the present embodiment includes a check valve 21 and a bypass metering valve 22. The check valve 21 is provided in a flow path that branches a flow path from the centrifugal pump 4 toward the first pump unit 19. The check valve 21 prevents the fuel Q from flowing from the downstream side toward the upstream side (centrifugal pump 4 side) of the check valve 21. The fuel Q that has passed through the check valve 21 flows into the second pump unit 20. The flow path on the discharge side of the second pump unit 20 branches into a bypass flow path 23 and a discharge flow path 24. The downstream side of the bypass channel 23 is joined between the inflow side of the second pump unit 20 and the check valve 21. The downstream side of the discharge flow path 24 joins the discharge side of the first pump unit 19.

  The bypass metering valve 22 is provided in the bypass channel 23. The bypass metering valve 22 adjusts the ratio of the amount of fuel Q flowing through the bypass flow passage 23 to the amount of fuel Q discharged from the second pump unit 20 (hereinafter referred to as the opening ratio). The bypass metering valve 22 monitors the pressure of the fuel Q before and after passing through the bypass metering valve 22, and is controlled by the control unit 10 to adjust the opening ratio, which is an adjustment amount by the bypass metering valve.

  When the opening ratio of the bypass metering valve 22 is minimum (fully closed), almost all of the fuel Q discharged from the second pump unit 20 passes through the discharge passage 24 and passes through the first pump unit 19. Together with the fuel Q discharged from the gear pump 5. At this time, the substantial discharge amount of the second pump unit 20 is substantially the same as the discharge amount of the first pump unit 19.

  When the opening ratio of the bypass metering valve 22 is the maximum (fully open), almost all of the fuel Q discharged from the second pump unit 20 passes through the bypass flow path 23 and passes through the second pump unit 20. Returned to the inflow side. At this time, the check valve 21 is closed and the fuel Q does not flow from the centrifugal pump 4 to the second pump unit 20. Further, the second pump unit 20 does not substantially work on the fuel Q, and does not substantially contribute to the discharge amount of the gear pump 5. That is, the discharge amount of the second pump unit 20 is substantially zero.

  FIG. 3 is a graph showing an example of the discharge amount of the gear pump 5 when the opening ratio of the bypass metering valve 22 is changed. The parallel operation in FIG. 3 indicates an operation state in which the bypass metering valve 22 is fully closed, and the series operation indicates an operation state in which the bypass metering valve 22 is fully open. The switching transient state indicates an operating state in which the opening ratio of the bypass metering valve 22 is greater than 0% and less than 100%. At this time, in the switching transition state, after the discharge flow rate becomes constant, the pressure is settled and a series operation state is set.

  In the example shown in FIG. 3, the operation state is initially parallel operation. By reducing the opening ratio of the bypass metering valve 22 from 100% to 0% over time, the operation state is switched from the parallel operation to the series operation through the switching transient state. Further, by increasing the opening ratio of the bypass metering valve 22 from 0% to 100% over time, the operating state is switched from the series operation to the parallel operation through the switching transient state. The discharge amount of the gear pump 5 during the parallel operation is substantially the same as the discharge amounts of the two double gear pumps connected in parallel. The discharge amount of the gear pump 5 in the switching transition state changes according to the opening ratio of the bypass metering valve 22. The discharge amount of the gear pump 5 at the time of series operation is substantially the same as the discharge amount of two double gear pumps connected in series, that is, the discharge amount of one double gear pump.

  The control unit 10 of the present embodiment controls the discharge rate of the gear pump 5 by controlling the opening ratio of the bypass metering valve 22 within a range in which the operation state becomes a switching transient state. In the present embodiment, the frequency at which the control unit 10 controls the opening ratio of the bypass metering valve 22 is higher than the frequency at which the control unit 10 controls the rotation speed of the servo motor 6. For example, the rotation speed of the servo motor 6 is controlled at 5 Hz, and the opening ratio of the bypass metering valve 22 is controlled at 0.5 Hz.

  In the present embodiment, the control unit 10 determines the control amount based on the value measured by the metering unit 8 as the flow rate of the fuel Q flowing to the fuel cooler 9. The control unit 10 controls the bypass metering valve 22 at a relatively high frequency by using the fluctuation component that has passed through the high-pass filter. The control unit 10 controls the servo motor 6 at a lower frequency than the bypass metering valve 22 by using the fluctuation component that has passed through the low-pass filter.

  Here, it is assumed that only the rotation speed of the servo motor 6 is controlled without controlling the opening ratio of the bypass metering valve 22 and the discharge amount of the gear pump 5 is controlled. In general, the energy required to change the opening ratio of the valve is smaller than the energy to change the torque of the servo motor. In the above case, if the servo motor 6 is controlled to follow the high frequency fluctuation of the discharge amount, it is necessary to set the maximum value of the angular acceleration of the servo motor 6, and the power to the servo motor 6 and the servo motor 6 is required. The supply source becomes large.

  In the fuel supply device 1 of the present embodiment, the discharge amount of the fuel Q can be rapidly changed by adjusting the opening ratio of the bypass metering valve 22. Therefore, when the discharge amount of the fuel Q needs to be changed suddenly, the necessity of changing the rotation speed of the servo motor 6 rapidly is reduced. Accordingly, the servo motor 6 and the power supply source for the servo motor 6 can be handled with high accuracy without causing an increase in the discharge amount, and the discharge flow rate shown in FIG. The discharge amount can also be changed, for example, by changing.

  Further, the rotational speed of the gear pump 5 can be freely controlled as compared with the configuration in which the gear pump is driven by the rotational movement of the fan. Therefore, even when the fuel efficiency changes due to the operating state of the jet engine 2, the discharge amount of the gear pump 5 can be controlled according to the fuel efficiency. Therefore, it is possible to reduce or eliminate excess fuel exceeding the fuel consumption in the fuel Q discharged from the gear pump 5, and the necessity of providing a mechanism for returning the excess fuel upstream of the gear pump 5 is reduced. In addition, the amount of the fuel Q returned to the upstream and circulated can be reduced or eliminated, and the temperature rise of the fuel Q due to the circulation of the fuel Q can be suppressed. Thereby, the load of the fuel cooler 9 can be reduced, and the fuel cooler 9 can be reduced in size and weight.

  In the above-described embodiment, the configuration in which the servo motor 6 rotates the first gear 17 and the second gear 18 via the drive gear 16 is exemplified. However, the servo motor 6 is different from the motor that rotates the first gear 17. The structure which rotates the 2nd gear 18 with this motor may be sufficient. Further, the first gear 17 and the second gear 18 are meshed with each other, and the servomotor 6 rotates one of the first gear 17 and the second gear 18 so that the first gear 17 is rotated. A configuration may be employed in which both 17 and the second gear 18 rotate in conjunction with each other. Further, instead of using a triple gear pump, a plurality of gear pumps may be connected and used. For example, the first pump portion and the second pump portion may each be constituted by a double gear pump.

DESCRIPTION OF SYMBOLS 1 ... Fuel supply apparatus, 2 ... Jet engine, 3 ... Fuel tank, 4 ... Centrifugal pump, 5 ... Gear pump, 6 ... Servo motor, 7 ... Flow volume switching part, DESCRIPTION OF SYMBOLS 8 ... Metering part, 9 ... Fuel cooler, 10 ... Control part, 11 ... Engine combustor, 12 ... Fan, 13 ... Relief valve, 14 ... Fuel supply interruption | blocking Valves, 15 ... casing, 16 ... driving gear, 17 ... first gear, 18 ... second gear, 19 ... first pump section, 20 ... first 2 pump part, 21 ... check valve, 22 ... bypass metering valve, 23 ... bypass flow channel, 24 ... discharge flow channel, Q ... fuel, R ... lubricating oil, S ... Propulsion system

Claims (3)

A first pump section for flowing fuel by rotation of the first gear;
A second pump section for flowing fuel by rotation of the second gear;
A metering unit for measuring the flow rate of the fuel flowing in from the first pump unit and the second pump unit;
A bypass metering valve for adjusting a flow rate of the fuel flowing from the second pump unit to the metering unit;
A drive unit for rotationally driving the first gear;
With adjusting the rotation speed of the controls the driving unit first gear, Bei example a control unit for controlling the adjustment amount of the flow rate of the fuel by the bypass metering valve,
The drive unit is a motor,
The fuel supply apparatus , wherein a frequency at which the control unit controls the drive unit is lower than a frequency at which the control unit controls the bypass metering valve . The drive unit includes a drive gear meshed with the first gear and the second gear, and drives the first gear and the second gear via the drive gear. Item 4. The fuel supply device according to Item 1. A bypass flow path for returning the fuel discharged from the second pump section to the upstream side of the second pump section;
A discharge flow path for joining the fuel discharged from the second pump part with the fuel discharged from the first pump part,
The fuel supply device according to claim 1 , wherein the metering unit is disposed downstream of the fuel via the discharge flow path, and the bypass metering valve is disposed in the bypass flow path.

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