JP2006046190A - Fluid supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid supply device capable of reducing frequency of cavitation occurrence. <P>SOLUTION: This device is provided with a vane pump 12 delivering fuel and a delivery pipe 13 supplied with fuel by the vane pump 12, pressure in the delivery pipe 13 is maintained between an upper limit value and a lower limit value established beforehand through adjustment of fuel supply quantity to the delivery pipe 13 from the vane pump 12. An electromagnetic valve 17 only fully closing or fully opening a low pressure piping 20 is provided in the low pressure piping 20 in a suction opening side of the vane pump 12. An electronic control device 30 controls open and close of the electromagnetic valve 17 based on pressure in the delivery pipe 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes a pump that discharges fluid and a volume chamber to which fluid is supplied from the pump, and the pressure in the volume chamber is set to a predetermined upper limit value through adjustment of the fluid supply amount from the pump to the volume chamber. The present invention relates to a fluid supply device that maintains a pressure between the lower limit and the lower limit.

  Conventionally, as such a fluid supply device, for example, there is a device used for a fuel system of an internal combustion engine. The fluid supply device used in this fuel system includes a delivery pipe connected to a fuel injection valve to form a volume chamber, a pump for supplying fuel to the delivery pipe, and the like. Then, by adjusting the amount of fuel supplied from the pump to the delivery pipe, the pressure in the delivery pipe is maintained within a range suitable for fuel injection.

  The adjustment of the amount of fuel supplied from the pump to the delivery pipe can be performed by adjusting the amount of fuel sucked into the pump and increasing or decreasing the amount of fuel discharged from the pump. The adjustment of the suction amount of the pump can be performed by providing a variable throttle valve in the fluid passage on the suction port side of the pump.

  When such a variable throttle valve is used, the pump suction amount can be arbitrarily changed through the change of the flow passage area of the fluid passage, so that the pump discharge amount can also be arbitrarily adjusted. The pressure in the pipe can be maintained in the vicinity of a desired target pressure.

In addition, as a prior art document concerning this invention, the patent document 1 shown below is mentioned.
JP 2003-201976 A

  By the way, when the flow rate on the suction side of the pump is limited by the variable throttle valve, the fluid speed increases at the variable throttle valve portion, and the fluid pressure locally decreases. For this reason, a part of the fluid evaporates to generate bubbles, and the bubble collapses thereafter, so-called cavitation occurs. In such a case, the bubbles are mixed in the fluid passage on the downstream side of the variable throttle valve, for example, the pump. Therefore, when the bubbles collapse in the pump, the inside of the pump corrodes due to a phenomenon called erosion. It may be in such a state. In particular, as described above, when the pressure in the delivery pipe is controlled by adjusting the flow rate on the suction side of the pump by using a variable throttle valve, cavitation may occur constantly. Damage to the pump due to this will also be more significant.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a fluid supply apparatus capable of reducing the occurrence frequency of cavitation.

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 includes a pump for discharging fluid and a volume chamber to which fluid is supplied from the pump, and through adjustment of the fluid supply amount from the pump to the volume chamber, In the fluid supply apparatus for maintaining the pressure at a pressure between a preset upper limit value and lower limit value, an opening / closing means provided in a fluid passage on the suction port side of the pump for opening and closing the fluid passage, and the volume chamber And a control means for controlling the opening / closing means on the basis of the pressure.

  In this configuration, the fluid supply amount to the volume chamber can be adjusted by controlling the opening / closing means provided in the fluid passage on the suction port side of the pump based on the pressure in the volume chamber. The indoor pressure can be maintained at a pressure between a preset upper limit value and lower limit value.

  Here, in the same configuration, the local pressure drop of the fluid accompanying the decrease in the flow passage area of the fluid passage causes the timing immediately after the fluid passage starts to be opened by the opening / closing means, and the fluid passage is closed. Since it occurs only at the immediately preceding timing, cavitation is likely to occur only at such timing. Further, when the fluid is supplied from the pump to the volume chamber, the flow rate on the suction side of the pump is not limited, so that cavitation is less likely to occur compared to the case where the variable throttle valve as described above is used. Therefore, according to this configuration, when adjusting the amount of fluid supplied from the pump to the volume chamber, the frequency of occurrence of cavitation can be reduced compared to the case where the variable throttle valve as described above is used. Become.

  In this configuration, the amount of fluid supplied from the pump to the volume chamber is adjusted through the opening and closing of the fluid passage. Therefore, the flow amount of the fluid passage can be arbitrarily changed by using the variable throttle valve, and thereby the supply amount can be easily controlled as compared with the case where the fluid supply amount is adjusted. .

  In controlling the opening / closing means based on the pressure in the volume chamber, as in the invention according to claim 2, the control means opens the opening / closing means when the pressure in the volume chamber is less than the lower limit value. By adopting a configuration in which the opening / closing means is closed when the pressure in the volume chamber exceeds the upper limit value, the pressure in the volume chamber is reliably set to a predetermined upper limit value and lower limit value. It will be possible to maintain the pressure between.

  As the opening / closing means, a variable throttle valve can be used. However, in the present invention, the fluid passage only needs to be fully opened and fully closed. It is possible to use a solenoid valve that can only make the passage fully open and fully closed. Therefore, the above-described effects can be obtained with a cheaper configuration.

Invention of Claim 4 makes it the summary that the said pump is a vane pump or a gear pump in the fluid supply apparatus of any one of Claims 1-3.
As described above, the fluid supply to the volume chamber is performed through opening / closing of the opening / closing means based on the pressure in the volume chamber. For this reason, it is desirable that the pump discharge interval be as short as possible in order to meter the fluid supply amount as precisely as possible in accordance with the pressure in the volume chamber.

  In this respect, the vane pump and the gear pump generally have a feature that the fluid discharge interval is shorter than that of the plunger-type pump. Therefore, according to the above configuration, it is possible to suitably adjust the pressure in the volume chamber through the control of the opening / closing means.

  According to the fifth aspect of the present invention, a configuration is adopted in which the fuel injection valve of the internal combustion engine is connected to the delivery pipe, and the fluid supply device is a device that supplies fuel to the delivery pipe. As a result, the pressure in the delivery pipe can be suitably maintained, and the occurrence frequency of cavitation in the pump that supplies fuel to the delivery pipe can be suppressed. The occurrence of erosion can be suppressed.

Hereinafter, an embodiment of a fluid supply device according to the present invention will be described with reference to FIGS.
FIG. 1 schematically shows the configuration of a fuel supply device for an internal combustion engine to which the fluid supply device is applied.

  As shown in FIG. 1, the fuel in the fuel tank 10 is sucked into the feed pump 11, and the fuel discharged from the feed pump 11 is sucked into the vane pump 12 through the low-pressure pipe 20 and the electromagnetic valve 17.

  The electromagnetic valve 17 is a valve that can bring the low-pressure pipe 20, which is a fluid passage, into a fully open state and a fully closed state, and constitutes the opening / closing means. The vane pump 12 is a known pump as shown in FIG. That is, the vane pump 12 is provided with a drive shaft 12a connected to a crankshaft or the like of the internal combustion engine, and a rotor 12b that rotates integrally with the drive shaft 12a is provided with a plurality of vanes 12c. In the cam ring 12d that accommodates the rotor 12b and the vane 12c, the inner peripheral surface 12e is formed in an elliptical shape, and a pump chamber 12f is formed between the inner peripheral surface 12e and each vane 12c. ing. When the volume of the pump chamber 12f increases with the rotation of the rotor 12b, fluid (fuel) is sucked into the pump chamber 12f from the suction port 12g connected to the low-pressure pipe 20. When the volume of the pump chamber 12f decreases with the rotation of the rotor 12b, the fluid sucked into the pump chamber 12f is discharged from the discharge port 12h in a pressurized state. In the vane pump 12 having such a structure, fuel is discharged from each pump chamber 12f as needed with the rotation of the rotor 12b. Therefore, the fuel discharge interval is shorter than that of the plunger type pump.

  The pressurized fuel discharged from the vane pump 12 is supplied to a delivery pipe 13 having a predetermined volume via a high-pressure pipe 21 connected to the discharge port 12h. The delivery pipe 13 constitutes the volume chamber. The delivery pipe 13 is connected with a fuel injection valve 14 for injecting and supplying fuel to the internal combustion engine. Further, the delivery pipe 13 is provided with a pressure sensor 15 for detecting the internal pressure, that is, the fuel pressure P that is the pressure of the fuel.

  A return pipe 22 for returning a part of the fuel flowing through the low-pressure pipe to the fuel tank 10 is connected in the middle of the low-pressure pipe, and a fuel pressure in the low-pressure pipe is provided in the middle of the return pipe 22. A regulator 16 is provided to keep the constant.

  The fuel pressure P in the delivery pipe 13 is maintained at a pressure suitable for fuel injection, and the fuel pressure P is maintained by adjusting the amount of fuel supplied from the vane pump 12 to the delivery pipe 13. Is called.

  That is, when the solenoid valve 17 is opened, fuel is supplied to the vane pump 12, so that fuel corresponding to the intake amount is discharged from the vane pump 12 and fuel is supplied to the delivery pipe 13. It becomes like this. When the fuel is supplied to the delivery pipe 13 in this way, the pressure in the delivery pipe 13 increases according to the supply amount.

  When the electromagnetic valve 17 is closed, the fuel supply to the vane pump 12 is interrupted, and the discharge amount of the vane pump 12 becomes “0”. In this case, the pressure in the delivery pipe 13 is maintained at the pressure when the electromagnetic valve 17 is closed, and decreases every time fuel injection is performed by the amount of injected fuel.

  Such fuel pressure control, specifically, opening / closing control of the electromagnetic valve 17 is performed by an electronic control unit 30 configured with a central processing unit (CPU) as an inside. The electronic control device 30 receives detection signals from the pressure sensor 15 and various sensors that detect the engine operating state. Then, a target value of the fuel pressure P is set according to the operation state of the internal combustion engine grasped by the detection signals of various sensors, and the maximum allowable value as a pressure range in the delivery pipe 13 with this target value as a center value. A fuel pressure and a minimum fuel pressure are respectively determined. The electronic control unit 30 controls opening and closing of the electromagnetic valve 17 via the drive circuit 40 so that the pressure in the delivery pipe 13 is maintained within this pressure range.

  Next, FIG. 3 shows a processing procedure for the opening / closing control of the electromagnetic valve 17 executed by the electronic control unit 30. This process is repeatedly executed every predetermined period. The opening / closing control process constitutes the control means.

  When this process is started, first, it is determined whether or not the fuel pressure P detected by the pressure sensor 15 is equal to or lower than the lower limit value Pmin (S100). The lower limit value Pmin is set to a pressure value slightly higher than the required minimum fuel pressure. The lower limit Pmin may be set to the same value as the minimum fuel pressure.

  When the fuel pressure P is equal to or lower than the lower limit value Pmin (S100: YES), the solenoid valve 17 is opened in order to supply fuel to the delivery pipe 13 and increase the pressure in the delivery pipe 13. (S110), and this process is temporarily terminated.

  On the other hand, when the fuel pressure P is higher than the lower limit value Pmin (S100: NO), it is determined whether or not the fuel pressure P is equal to or higher than the upper limit value Pmax (S120). The upper limit value Pmax is set to a pressure value slightly lower than the required maximum fuel pressure. The upper limit value Pmax may be set to the same value as the maximum fuel pressure.

  When the fuel pressure P is equal to or higher than the upper limit value Pmax (S120: YES), the solenoid valve 17 is used to interrupt the fuel supply to the delivery pipe 13 and stop the pressure increase in the delivery pipe 13. The valve is closed (S130), and this process is temporarily terminated.

  On the other hand, when the fuel pressure P is less than the upper limit value Pmax (S120: NO), the current open / close state of the solenoid valve 17 is maintained (S140), and this process is temporarily terminated. By the processing in step S140, the electromagnetic valve 17 is maintained in the open state during the pressure increase in the delivery pipe 13, and after the pressure increase in the delivery pipe 13 is completed, the pressure in the delivery pipe 13 becomes the lower limit value. The electromagnetic valve 17 is maintained in a closed state until it falls below Pmin.

FIG. 4 schematically shows the pressure in the delivery pipe 13 when the opening / closing control is performed, that is, the transition of the fuel pressure P, the control state of the solenoid valve, and the like.
As shown in FIG. 4, when fuel is injected from the fuel injection valve 14 (time t1, t2), the fuel pressure P decreases according to the injection amount. When the fuel pressure P becomes equal to or lower than the lower limit value Pmin (time t3), the solenoid valve 17 is opened. By opening the electromagnetic valve 17, fuel is discharged from the vane pump 12, and the fuel pressure P gradually increases as the fuel is supplied into the delivery pipe 13. That is, boosting in the delivery pipe 13 is performed. When the fuel pressure P reaches the upper limit value Pmax (time t4), the solenoid valve 17 is closed. By closing the electromagnetic valve 17, fuel supply to the vane pump 12 is interrupted, and the fuel pressure P is maintained at the pressure when the electromagnetic valve 17 is closed. After that, every time fuel injection is performed (time t5, t6), the fuel pressure P decreases according to the injection amount, and when the fuel pressure P becomes lower than the lower limit Pmin again, the solenoid valve 17 is opened. Thus, the pressure in the delivery pipe 13 is increased.

  Thus, in this embodiment, the solenoid valve 17 is provided in the fluid passage (low pressure pipe 20) on the suction port 12g side of the vane pump 12. Then, by controlling the opening and closing of the electromagnetic valve 17 based on the pressure in the delivery pipe 13, the amount of fuel supplied to the delivery pipe 13 can be metered, whereby the pressure in the delivery pipe 13 is preliminarily adjusted. The pressure between the set upper limit value Pmax and lower limit value Pmin can be maintained.

  Here, in this embodiment, the local pressure drop of the fuel accompanying the reduction in the flow path area of the low pressure pipe 20 is the timing immediately after the low pressure pipe 20 starts to be opened by the electromagnetic valve 17 (time t3 in FIG. 4). ) And the timing just before the low-pressure pipe 20 is closed (time t4 in FIG. 4), cavitation is likely to occur only at such timing. Further, when the fuel is supplied from the vane pump 12 to the delivery pipe 13, the flow rate on the suction side of the vane pump 12 is not limited, so that cavitation occurs compared to the case where the variable throttle valve as described above is used. It becomes difficult. Therefore, when the amount of fuel supplied from the vane pump 12 to the delivery pipe 13 is adjusted, the frequency of occurrence of cavitation can be reduced as compared with the case where the variable throttle valve as described above is used. Therefore, for example, in the vane pump 12 that supplies fuel to the delivery pipe 13, the occurrence of erosion caused by cavitation can be suppressed.

  In the present embodiment, the fuel supply amount from the vane pump 12 to the delivery pipe 13 is adjusted through the opening and closing of the low-pressure pipe 20. Therefore, it is possible to easily control the supply amount as compared with the case where the flow passage area of the low-pressure pipe 20 is arbitrarily changed by using the variable throttle valve, and thereby the fuel supply amount is adjusted. .

  Although a variable throttle valve can be used as a valve for opening and closing the low-pressure pipe 20, in this embodiment, the low-pressure pipe 20 only needs to be fully opened and fully closed. The solenoid valve 17 that can be in a closed state only can be used. Therefore, the above-described effects can be obtained with a cheaper configuration.

  Further, as described above, the fuel supply to the delivery pipe 13 is performed through the opening / closing control of the electromagnetic valve 17 based on the pressure in the delivery pipe 13. Therefore, when the discharge interval of the pump is relatively long, even if the solenoid valve 17 is closed based on the pressure, a large amount of fuel is continuously supplied into the delivery pipe 13 and the pressure is exceeded. There is a risk of shooting. Therefore, in order to adjust the fuel supply amount as precisely as possible according to the pressure in the delivery pipe 13, it is desirable that the pump discharge interval be as short as possible. In this regard, in the present embodiment, the opening / closing control is performed in a fluid supply apparatus using a vane pump having a fluid discharge interval shorter than that of a plunger pump. Therefore, the pressure in the delivery pipe 13 can be appropriately adjusted through the opening / closing control of the electromagnetic valve 17.

As described above, according to the present embodiment, the following effects can be obtained.
(1) A vane pump 12 that discharges fuel and a delivery pipe 13 to which fuel is supplied from the vane pump 12 are provided, and the pressure in the delivery pipe 13 is adjusted in advance through adjustment of the amount of fuel supplied from the vane pump 12 to the delivery pipe 13. The pressure is maintained between the set upper limit value and lower limit value. In such a fluid supply device, an electromagnetic valve 17 is provided in the low-pressure pipe 20 on the suction port 12 g side of the vane pump 12, and the opening and closing of the electromagnetic valve 17 is controlled based on the pressure in the delivery pipe 13. Therefore, the amount of fuel supplied to the delivery pipe 13 can be metered, whereby the pressure in the delivery pipe 13 can be maintained at a pressure between a preset upper limit value and lower limit value.

  Here, in the above embodiment, cavitation is likely to occur only at the timing immediately after the low-pressure pipe 20 starts to be opened by the electromagnetic valve 17 and at the timing just before the low-pressure pipe 20 is closed. Further, when fuel is supplied from the vane pump 12 to the delivery pipe 13, cavitation is less likely to occur than when the variable throttle valve is used. Therefore, when the amount of fuel supplied from the vane pump 12 to the delivery pipe 13 is adjusted, the frequency of occurrence of cavitation can be reduced as compared with the case where the variable throttle valve as described above is used.

  (2) The fuel supply amount from the vane pump 12 to the delivery pipe 13 is adjusted through the opening and closing of the low-pressure pipe 20. Therefore, as compared with the case where the flow area of the low-pressure pipe 20 is arbitrarily changed using a variable throttle valve, and the fuel supply amount is adjusted, the supply amount can be controlled easily. Become.

  (3) In the opening / closing control of the solenoid valve 17 based on the pressure in the delivery pipe 13, when the fuel pressure P is less than the lower limit value Pmin, the solenoid valve 17 is opened, and when the fuel pressure P exceeds the upper limit value Pmax. The electromagnetic valve 17 is closed. Therefore, the pressure in the delivery pipe 13 can be reliably maintained at a pressure between the upper limit value Pmax and the lower limit value Pmin.

  (4) In order to make the low-pressure pipe 20 fully open and fully closed, an electromagnetic valve 17 that can make the low-pressure pipe 20 fully open and fully closed is used. Therefore, compared with the case where the variable throttle valve is used, the above-described effects can be obtained with a cheaper configuration.

  (5) As the pump whose discharge amount is adjusted by opening and closing the electromagnetic valve 17, the vane pump 12 having a feature that the fluid discharge interval is shorter than that of the plunger type pump is used. Therefore, the pressure adjustment in the delivery pipe 13 through the opening / closing control of the electromagnetic valve 17 can be suitably performed.

  (6) The fluid supply apparatus according to the present invention is applied to an apparatus that supplies fuel to the delivery pipe 13 that is a volume chamber. Therefore, the pressure in the delivery pipe 13 can be suitably maintained, and the occurrence frequency of cavitation in the pump that supplies fuel to the delivery pipe 13 can be suppressed. Therefore, the occurrence of erosion in the pump due to cavitation can be suppressed.

In addition, each said embodiment can also be changed and implemented as follows.
In the above embodiment, the target value of the fuel pressure P is set according to the operating state of the internal combustion engine, and the maximum fuel pressure and the minimum fuel pressure allowed as the pressure range in the delivery pipe 13 are set with the target value as the center value I asked for each. That is, since the maximum fuel pressure and the minimum fuel pressure are variable values set according to the engine operating state, the upper limit value Pmax and the lower limit value Pmin are also variable values set according to the engine operating state. On the other hand, the maximum fuel pressure and the minimum fuel pressure may be set in advance as fixed values, and the upper limit value Pmax and the lower limit value Pmin may also be set to preset fixed values.

  In the above embodiment, the opening and closing of the electromagnetic valve 17 is controlled by the electronic control unit 30. In short, it is only necessary that the electromagnetic valve 17 can be opened and closed based on the pressure in the delivery pipe 13. Therefore, you may make it control opening and closing of the solenoid valve 17 using a relay circuit etc., for example.

  In the above embodiment, the opening / closing means is the electromagnetic valve 17, but it may be anything as long as the fluid passage can be fully opened and fully opened. Therefore, the opening / closing mode can be selected as appropriate. A hydraulic valve may be used.

  A gear pump that sucks and discharges fluid by rotating a gear also has a feature that a fluid discharge interval is shorter than that of a plunger-type pump. Therefore, even if the fluid supply device according to the present invention is applied to a fluid supply device including such a gear pump instead of the vane pump 12, the same effects as those of the above-described embodiment can be obtained.

  In the above embodiment, the fluid supply apparatus according to the present invention is applied to an apparatus (fuel supply apparatus) that supplies fuel to the delivery pipe 13 that is a volume chamber, but the application target is not limited to this. . In short, a pump that discharges fluid and a volume chamber to which fluid is supplied from the pump are provided, and the pressure in the volume chamber is set to a preset upper limit value through adjustment of the fluid supply amount from the pump to the volume chamber. Any fluid supply device that maintains a pressure between the lower limit and the lower limit can be applied in the same manner.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the structure of the fuel supply apparatus of the internal combustion engine to which this is applied about one Embodiment of the fluid supply apparatus concerning this invention. The schematic structure figure of a vane pump. The flowchart which shows the process sequence about the opening / closing control of the solenoid valve in the embodiment. The timing chart which shows typically the transition of the fuel pressure in a delivery pipe when the opening / closing control is performed, the control state of a solenoid valve, and the like.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fuel tank, 11 ... Feed pump, 12 ... Vane pump, 12a ... Drive shaft, 12b ... Rotor, 12c ... Vane, 12d ... Cam ring, 12e ... Inner peripheral surface, 12f ... Pump chamber, 12g ... Inlet, 12h ... Discharge Outlet, 13 ... Delivery pipe, 14 ... Fuel injection valve, 15 ... Pressure sensor, 16 ... Regulator, 17 ... Solenoid valve, 20 ... Low pressure piping, 21 ... High pressure piping, 22 ... Return piping, 30 ... Electronic control unit, 40 ... Driving circuit.

Claims (5)

A pump for discharging fluid; and a volume chamber to which fluid is supplied from the pump; and by adjusting the amount of fluid supplied from the pump to the volume chamber, the pressure in the volume chamber is set to a preset upper limit value; In the fluid supply device that maintains the pressure between the lower limit value,
Opening and closing means provided in the fluid passage on the suction port side of the pump to open and close the fluid passage;
And a control means for controlling the opening / closing means based on the pressure in the volume chamber. The control means opens the opening / closing means when the pressure in the volume chamber is less than the lower limit value, and closes the opening / closing means when the pressure in the volume chamber exceeds the upper limit value. Item 2. The fluid supply device according to Item 1. The fluid supply apparatus according to claim 1, wherein the opening / closing means is an electromagnetic valve capable of opening the fluid passage only in a fully open state and a fully closed state. The fluid supply device according to claim 1, wherein the pump is a vane pump or a gear pump. 5. The fluid according to claim 1, wherein the volume chamber is a delivery pipe to which a fuel injection valve of an internal combustion engine is connected, and the fluid supply device is a device that supplies fuel to the delivery pipe. Feeding device.

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