JP2011220297A - Fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supply device capable of changing a pressure of a fuel to be supplied.SOLUTION: In the fuel supply device 1, a primary pump 10 discharges fuel stored in a fuel tank 5 to a fuel passage 31. A first control valve 15 adjusts a pressure of the fuel discharged by the primary pump 10 at a first pressure value or lower. A check valve 40 is provided at the fuel passage 31, and prevents the back flow of the fuel to the upstream side. A secondary pump 20 discharges the fuel stored in the fuel tank 5 to a discharge passage 33 communicating with the fuel passage 31 at the downstream side of the check valve 40. A second control valve 25 adjusts a pressure of the fuel discharged by the second pump at a second pressure value or lower, the second pressure value higher than the first pressure value. Accordingly, the pressure of the fuel supplied to the outside of the fuel tank 5 via the fuel passage 31 and the discharge passage 33 is variably controlled.

Description

  The present invention relates to a fuel supply device that supplies fuel in a fuel tank to the outside of the fuel tank.

  Conventionally, a fuel supply device that supplies fuel from a fuel tank to the outside of the fuel tank is known. In such a fuel supply device, it may be required to supply the fuel at a high pressure in order to crush the vapor generated in the pipe. Further, particularly when the engine is heavily loaded, it is required to supply the fuel at a high pressure in order to atomize the injected fuel in order to increase the engine output.

  On the other hand, when the pressure of the fuel supplied from the fuel supply device is increased, there is a problem that the durability performance of the fuel supply device decreases. In order to solve this problem, a fuel supply device including a back pressure control pump that supplies fuel to a back pressure chamber of a pressure regulator to increase the pressure of the fuel separately from the primary pump is disclosed (for example, Patent Documents). 1).

Japanese Patent No. 4399743

By the way, the back pressure control pump of Patent Document 1 does not supply fuel to the delivery pipe except when the primary pump fails. Therefore, when the primary pump is not broken, even if the back pressure control pump is driven, it is only possible to increase the fuel pressure in the discharge side passage as compared with the case where only the primary pump is driven.
The present invention has been made in view of the above-described problems, and an object thereof is to provide a fuel supply device capable of changing the pressure of fuel to be supplied.

  The fuel supply device according to claim 1 includes a fuel passage member, a first pump, a first control valve, a check valve, a discharge passage member, a second pump, and a second control valve. And comprising. The fuel passage member has a fuel passage for sending fuel stored in the fuel tank to the outside of the fuel tank. The first pump discharges the fuel stored in the fuel tank to the fuel passage. The first control valve adjusts the pressure of the fuel discharged by the first pump to be equal to or lower than the first pressure value. The check valve is provided in the fuel passage and prevents the fuel from flowing backward to the upstream side. The discharge passage member has a discharge passage communicating with the fuel passage on the downstream side of the check valve. The second pump discharges fuel stored in the fuel tank to the discharge passage. The second control valve adjusts the pressure of the fuel discharged by the second pump to be equal to or lower than the second pressure value that is higher than the first pressure value.

  In the present invention, the first pump discharges fuel to the outside of the fuel tank via the fuel passage. The fuel discharged by the first pump is adjusted by the first control valve so as to be equal to or lower than the first pressure value. The second pump discharges fuel to the outside of the fuel tank via the discharge passage and the fuel passage. The fuel discharged by the second pump is adjusted by the second control valve so as to be equal to or lower than the second pressure value higher than the first pressure value. Thereby, the pressure of the fuel supplied to the outside of the fuel tank can be made variable. For example, if pumps having different discharge performances are used for the first pump and the second pump, the pressure of the supplied fuel can be made variable while suppressing an increase in pump load.

  Further, the fuel pressure on the downstream side of the check valve can be kept higher than the fuel pressure on the upstream side of the check valve. As a result, even if the pressure in the fuel passage gradually decreases due to an engine stop or the like, the fuel pressure on the downstream side of the check valve is kept relatively high, so that the generation of vapor on the downstream side of the check valve is suppressed. can do. In particular, when the configuration described in claim 3 is employed, the occurrence of paper inside the high-pressure supply pump is suppressed, and the pressure can be reliably increased. In particular, when applied to a port injection type engine, when the engine is restarted, fuel maintained at a relatively high pressure on the downstream side of the check valve can be supplied to the injector, which facilitates atomization of the spray. , Unburned HC in the exhaust can be reduced, and emission can be suppressed.

According to the second aspect of the present invention, the maximum discharge amount that can be discharged by the first pump is larger than the maximum discharge amount that can be discharged by the second pump. In the present invention, for example, when the required discharge amount is small, such as during normal operation or idling when the engine is not in a high load state, the fuel pressure is lowered by driving the second pump having low discharge performance. Since it can suppress, a pump load is reduced and it contributes to the improvement of a fuel consumption by extension. Further, when the required discharge amount is large, the required amount of fuel can be discharged by driving the first pump having high discharge performance.
In addition, since a pump with low discharge performance is used as the second pump that supplies fuel to the fuel passage on the downstream side of the check valve held at high pressure, the high pressure can be maintained with a small flow rate.

  According to a third aspect of the present invention, there is provided a high-pressure supply pump that pressurizes and feeds fuel supplied from the first pump and the second pump via the fuel passage. Since the fuel can be pressurized by the high-pressure supply pump, precise control of the fuel pressure upstream from the high-pressure supply pump is not necessary. In particular, during normal operation, the fuel pressure upstream of the high-pressure supply pump can be kept low, which reduces the pump load and contributes to improved fuel efficiency. When the configuration of claim 2 is adopted and fuel is supplied by driving the first pump during high load operation, the first pressure value controlled by the first control valve is the value of the high pressure supply pump. It is desirable to set so that vapor does not occur when the rotational speed increases.

  According to a fourth aspect of the present invention, a fuel filter is provided between the first pump and the first control valve. Since the first pump and the first control valve are controlled at a low pressure compared to the downstream side of the check valve, compared to the case where the fuel filter is provided downstream of the check valve, A fuel filter with a low pressure resistance can be used. Further, as in the invention described in claim 5, a fuel filter may be provided between the second pump and the second control valve.

  According to a sixth aspect of the present invention, the fuel filter is provided at the junction where the fuel passage and the discharge passage merge. As a result, the foreign matter in the fuel discharged from the first pump and the foreign matter in the fuel discharged from the second pump can be removed by one fuel filter, so that the number of parts can be reduced.

  In at least one of the first pump and the second pump, the drive source is a brushless motor. By using a brushless motor, the life of the motor can be extended as compared with the case where a motor with a brush is used, and the entire apparatus can be downsized. In addition, control at low rotation becomes easy.

  According to an eighth aspect of the present invention, the apparatus includes a control unit having a pump control unit that controls driving of the first pump and the second pump based on an operating state of the internal combustion engine. Thus, the first pump and the second pump can be appropriately controlled based on the operating state of the internal combustion engine.

Specifically, the pump control means performs the following control.
In the ninth aspect of the invention, the pump control means controls the first pump to be driven when the operating state of the internal combustion engine is a high-load operating state. The pump control means controls to drive the second pump when the operation state of the internal combustion engine is a normal operation state or an idle state. In particular, when the configuration according to claim 2 is adopted, in the normal operation state or the idle state where the consumption flow rate in the internal combustion engine is small, the fuel pressure is lowered by supplying the fuel with the second pump having a low discharge performance. Since it can suppress, a pump load is reduced and it contributes to the improvement of a fuel consumption by extension. Further, when the internal combustion engine is in a high load operation state with a large consumption flow rate, it is possible to supply the required amount of fuel by supplying the fuel with the first pump having high discharge performance.

  In a tenth aspect of the present invention, the pump control means controls to drive the first pump and the second pump when the internal combustion engine is immediately after starting. Immediately after starting the internal combustion engine, even if the consumption flow rate of the engine temporarily increases due to the control for increasing the fuel injection amount, the fuel pressure is reduced by driving the first pump and the second pump. It can suppress that it falls from the 1st pressure value.

  In the invention according to claim 11, the control unit includes abnormality determination means for determining whether or not the second pump can be driven. When it is determined by the abnormality determination unit that the second pump cannot be driven, the pump control unit controls the first pump to be driven regardless of the operation state of the internal combustion engine. Thereby, even when the second pump cannot be driven, the fuel supply can be continued.

It is a schematic block diagram which shows the structure of the fuel supply apparatus by 1st Embodiment of this invention. It is a flowchart which shows the pump control processing by 1st Embodiment of this invention. It is explanatory drawing explaining the drive pattern of the pump by 1st Embodiment of this invention. It is a schematic block diagram which shows the structure of the fuel supply apparatus by 2nd Embodiment of this invention.

A fuel supply device according to the present invention will be described below with reference to the drawings.
(First embodiment)
A fuel supply apparatus according to a first embodiment of the present invention is shown in FIG.
The fuel supply device 1 supplies fuel to an engine (not shown) as an internal combustion engine. The fuel supply device 1 of the present embodiment is applied to a four-cylinder direct injection engine that directly injects fuel into a combustion chamber of the engine. The fuel supply apparatus 1 includes a fuel tank 5, a primary pump 10 as a first pump, a secondary pump 20 as a second pump, a fuel passage member 30, a discharge passage member 32, a check valve 40, a high-pressure supply pump 50, An electronic control device (hereinafter referred to as “ECU”) 60 as a control unit, a battery 62, a relay 64, a detection unit 66, and the like are provided.

  The primary pump 10 sucks the fuel stored in the fuel tank 5 and discharges the fuel to the fuel passage 31 formed in the fuel passage member 30. A check valve 11 is provided in the fuel passage 31 in the vicinity of the discharge port of the primary pump 10 to prevent the backflow of fuel to the primary pump 10 side. The fuel passage 31 communicates with the delivery pipe 55 via the high pressure supply pump 50. As a result, the fuel discharged from the primary pump 10 is supplied to the delivery pipe 55 via the fuel passage 31 and the high-pressure supply pump 50.

  The fuel passage 31 is provided with a check valve 40 that prevents the fuel from flowing back to the primary pump 10 side. The check valve 40 opens and closes with a differential pressure, and opens when the pressure on the primary pump 10 side of the check valve 40 becomes higher than the pressure on the opposite side of the primary pump 10 of the check valve 40. To do. Hereinafter, the primary pump 10 side of the check valve 40 is referred to as “upstream side”, and the opposite side of the check valve 40 from the primary pump 10 is referred to as “downstream side”. Then, it can be said that the check valve 40 opens when the upstream fuel pressure becomes higher than the downstream fuel pressure.

  The secondary pump 20 sucks the fuel stored in the fuel tank 5 and discharges the fuel to the discharge passage 33 formed in the discharge passage member 32. A check valve 21 is provided in the discharge passage 33 in the vicinity of the discharge port of the secondary pump 20 to prevent the backflow of fuel to the secondary pump 20 side. The discharge passage 33 communicates with the fuel passage 31 at a communication portion 34 on the downstream side of the check valve 40. As a result, the fuel discharged from the secondary pump 20 is supplied to the delivery pipe 55 via the discharge passage 33, the communication portion 34, the fuel passage 31, and the high-pressure supply pump 50.

  The fuel supplied to the delivery pipe 55 by the primary pump 10 and the secondary pump 20 is injected from the injector 56 into a fuel chamber of an engine (not shown). The fuel supply device 1 of the present embodiment is a so-called returnless system that does not include a return pipe that returns the surplus fuel in the delivery pipe 55 to the fuel tank 5.

  The maximum discharge amount of the primary pump 10 is larger than the maximum discharge amount of the secondary pump 20. In other words, it can be said that the discharge performance of the primary pump 10 is higher than the discharge performance of the secondary pump 20. Specifically, a pump with a maximum discharge flow rate of about 100 L / h is used for the primary pump 10, and a pump with a maximum discharge flow rate of about 25 L / h is used for the secondary pump 20. In addition, a DC motor with a brush is used as the drive source motor of the primary pump 10, and a brushless motor is used as the drive source motor of the secondary pump 20.

In the present embodiment, a first control valve 15 that adjusts the fuel pressure upstream of the check valve 40 and a second control valve 25 that adjusts the fuel pressure downstream of the check valve 40 are provided. .
The first control valve 15 adjusts the pressure of the fuel discharged from the primary pump 10 on the upstream side of the check valve 40 so as to be equal to or lower than the first pressure value. The first control valve 15 adjusts the fuel pressure between a fuel filter 45 and a check valve 40 described later to a first pressure value. The first pressure value is set to a pressure that does not generate vapor inside the high-pressure supply pump 50 when the number of rotations of the high-pressure supply pump 50 increases. Specifically, in the present embodiment, the first pressure value is set to 350 kPa. That is, the first control valve 15 opens when the fuel pressure upstream of the check valve 40 exceeds 350 kPa, and the fuel upstream of the check valve 40 is returned into the fuel tank 5.

  The second control valve 25 adjusts the pressure of the fuel discharged from the secondary pump 20 on the downstream side of the check valve 40 so as to be equal to or lower than the first pressure value. The second pressure value is set to a value higher than the first pressure value. Specifically, in the present embodiment, the second pressure value is set to 520 kPa. That is, the second control valve 25 opens when the fuel pressure downstream of the check valve 40 exceeds 520 kPa, and the fuel downstream of the check valve 40 is returned to the fuel tank 5.

  Hereinafter, the upstream side of the check valve 40 of the fuel passage 31 whose fuel pressure is controlled to 350 kPa or less which is the first pressure value by the first control valve 15 is referred to as an “upstream fuel passage 35”. In addition, the second control valve 25 controls the fuel pressure to a second pressure value of 520 kPa or less, the discharge passage 33, and the downstream side of the check valve 40 to the suction port of the high-pressure supply pump 50. The fuel passage 31 is referred to as a “downstream fuel passage 36”.

Foreign matters and the like are removed from the fuel supplied to the engine by the primary pump 10 and the secondary pump 20 by the fuel filter 45 and the suction filters 47 and 48.
The fuel filter 45 is provided between the primary pump 10 and the first control valve 15 and filters the fuel discharged from the primary pump 10. Since pressure loss is caused by the fuel filter 45, the fuel pressure after being filtered by the fuel filter 45 is adjusted by the first control valve 15. Since the upstream fuel passage 35 in which the fuel filter 45 is provided is adjusted to be 350 kPa or less, the fuel filter 45 may be one that can withstand a pressure of about 350 kPa, and may be provided in the downstream fuel passage 36. In comparison, it can have a lower breakdown voltage. Further, a filter with higher filtration accuracy than the suction filter 47 is employed.

The suction filter 47 removes foreign matters in the fuel sucked into the primary pump 10. Since the fuel discharged from the primary pump 10 is filtered by the fuel filter 45, a filter with relatively low filtration accuracy that can remove relatively large foreign matters is employed as the suction filter 47.
The suction filter 48 removes foreign matters in the fuel sucked into the secondary pump 20. In the present embodiment, a fuel filter that filters the fuel discharged from the secondary pump 20 is not provided. Therefore, it is preferable to employ a filter having a filtration accuracy higher than that of the suction filter 47 and having a filtration accuracy similar to that of the fuel filter 45 as the suction filter 48.

  The ECU 60 controls the drive of the primary pump 10, the secondary pump 20, the high-pressure supply pump 50, the injector 56, and the like. In FIG. 1, the control lines to the high-pressure supply pump 50 and the injector 56 are omitted to avoid complication.

  The battery 62 supplies power to the primary pump 10, the secondary pump 20, the ECU 60, and the like. A relay 64 is provided between the battery 62 and the secondary pump 20. The relay 64 is turned on and off by the ECU 60. By switching the relay 64 on and off, the drive of the secondary pump 20 is controlled. Between the relay 64 and the secondary pump 20, the detection part 66 for detecting whether the secondary pump 20 is driven is provided. In the present embodiment, a current supplied to the detection unit 66 is detected, and a detected detection signal is output to the ECU 60.

  Here, the pump control processing by the ECU 60 will be described based on the flowchart shown in FIG. The pump control process is executed at predetermined time intervals when the ignition is on. In FIG. 2, for convenience, the primary pump 10 is indicated as “FP1” and the secondary pump 20 is indicated as “FP2”.

<When starting the engine>
In the first step S101 (hereinafter, “step” is omitted and simply indicated by the symbol “S”), it is determined whether or not an abnormality flag F described later is set. When it is determined that the abnormality flag F is set (S101: YES), the process proceeds to S119. When it is determined that the abnormality flag F is not set (S101: NO), the process proceeds to S102.

  In S102, it is determined whether or not the starter motor is operating. When it is determined that the starter motor is not operating (S102: NO), the process proceeds to S109. If it is determined that the starter motor is operating (S102: YES), that is, if it is immediately after the engine is started, the routine proceeds to S103.

  In S103, it is determined whether or not the engine speed is greater than a predetermined number N. The determination process here determines whether or not the engine has shifted to the idle state. Therefore, the predetermined number N is the engine speed during idling. When the engine speed is greater than the predetermined number N (S103: YES), the process proceeds to S107. When the engine speed is equal to or less than the predetermined number N (S103: NO), that is, after the engine start meal and before the transition to the idle state, the process proceeds to S104.

In S104, the relay 64 is turned on.
In S105, it is determined whether or not the secondary pump 20 is driven. In this determination, the current to be supplied to the detection unit 66 is detected, and based on the detected value, when the amount of current to be supplied is not supplied, it is determined that the secondary pump 20 is not driven. When it is determined that the secondary pump 20 is not driven (S105: NO), that is, when the amount of current to be supplied to the detection unit 66 is not supplied, the process proceeds to S118. When it is determined that the secondary pump 20 is driven (S105: YES), that is, when the amount of current to be supplied to the detection unit 66 is supplied, the process proceeds to S106.
In S106, the primary pump 10 is driven.

When it is determined that the starter motor is operating (S102: YES), and the engine speed is greater than the predetermined number N (S103: YES), that is, immediately after the engine is started, the state shifts to the idle state. In S107, the process proceeds to the case where the primary pump 10 is turned off. That is, the secondary pump 20 and the primary pump 10 are driven immediately after the engine is started and before the transition to the idle state, but after the transition to the idle state, the driving of the first pump is stopped. Thus, only the secondary pump 20 is driven.
In S108, which moves after S106 or S107, the secondary pump 20 can be driven normally, and thus the abnormality flag F is not set.

<During normal operation>
In S109, when the starter motor is determined not to be operating (S102: YES), it is determined whether or not the engine operating state is a high load. Whether or not the engine has a high load is determined based on a map stored in advance according to the engine speed and torque. When it is determined that the engine operating state is a high load (S109: YES), the process proceeds to S116. When it is determined that the engine operating state is not a high load (S109: NO), the process proceeds to S110.

In S110, when the primary pump 10 is driving, the driving of the primary pump 10 is stopped. When the primary pump 10 is not driven, the state where it is not driven is continued.
In S111, when the relay 64 is not turned on, the relay 64 is turned on. When the relay 64 is turned on, the state where the relay 64 is turned on is continued.

  In S112, it is determined whether or not the secondary pump 20 is being driven. In this determination, as in the determination process in S105, the amount of current supplied to the detection unit 66 is detected, and the determination is made based on the detected value. When it is determined that the secondary pump 20 is not driven (S112: NO), the process proceeds to S118. When it is determined that the secondary pump 20 is being driven (S112: YES), the process proceeds to S113.

In S113, it is determined whether or not the engine is stopped. When it is determined that the engine is not stopped (S113: NO), the process proceeds to S115. When it is determined that the engine is stopped (S113: YES), the process proceeds to S114.
In S114, the relay 64 is turned off and the drive of the secondary pump 20 is stopped.
In S115, since the secondary pump 20 can be driven normally, the abnormality flag F is not set.

<During high load operation>
In S116, when the engine operating state is determined to be a high load (S109: YES), the relay 64 is turned off and the drive of the secondary pump 20 is stopped.
In S117, the primary pump 10 is driven.

<In case of abnormality>
In S118, when it is determined that the second pump is not driven despite the relay 64 being turned on (S105: NO or S112: NO), the abnormality flag F is set.

In S119, where the abnormality flag F is set (S101: YES), the relay 64 is turned off.
In S120, the primary pump 10 is driven.

In S121, it is determined whether or not the engine has been operated. When the engine can be operated (S121: YES), fuel is supplied only by the primary pump 10 without using the secondary pump 20. When the engine could not be operated (S121: NO), it is assumed that the parts other than the fuel supply device 1 are abnormal, and the process proceeds to S122.
In S122, the driving of the primary pump 10 is stopped.
In S123, the abnormality flag F is reset, and this process ends.

  Here, the relationship between the operating state of the engine and the driving state of the fuel supply device 1 will be described with reference to FIG. 3A shows the fuel pressure in the downstream fuel passage 36, FIG. 3B shows the consumption flow rate of fuel consumed by the engine, and FIG. 3C shows the primary pump 10 and the secondary pump 20. The drive state is shown. In FIG. 3, as in FIG. 2, for convenience, the primary pump 10 is indicated as “FP1” and the secondary pump 20 is indicated as “FP2”.

  As indicated by the alternate long and short dash line in FIG. 3A, the fuel pressure in the fuel passage in the conventional fuel supply device used in the direct injection engine increases the rotation speed of the high-pressure supply pump regardless of the operating state of the engine. Is substantially constant at a pressure (350 kPa in this example) at which vapor does not occur. In addition, after the engine stops, the fuel pressure gradually decreases.

  In the present embodiment, as shown by a solid line in FIG. 3A, the primary pump 10, the first control valve 15, the secondary pump 20, and the second control valve 25 are provided, depending on the operating state of the engine. The fuel pressure in the downstream fuel passage 36 is variable.

  In the present embodiment, the fuel pressure in the downstream fuel passage 36 that is downstream of the check valve 40 is higher than the fuel pressure in the upstream fuel passage 35 that is upstream of the check valve 40 (520 kPa in this embodiment). ). Therefore, if the fuel pressure in the downstream fuel passage 36 is maintained at the second pressure value of 520 kPa when the engine is stopped, even if there is a pressure drop during the stop period, The side fuel passage 36 maintains a high pressure close to 520 kPa. That is, since the fuel pressure in the downstream fuel passage 36 is maintained at a pressure sufficiently higher than the pressure at which vapor is generated in the high-pressure supply pump 50, the generation of vapor can be suppressed. In addition, since high-pressure fuel is supplied to the injector 56 when the engine is started, atomization of the fuel spray from the injector 56 is promoted, unburned HC in the exhaust can be reduced, and emission can be suppressed. it can.

  Immediately after the engine is started (S102: YES, S103: YES in FIG. 2), since the flow rate of the engine is small, basically, the secondary pump 20 with low discharge performance is driven to supply fuel to the engine ( S104, S105: YES). However, when the control of increasing the fuel injection amount immediately after the engine is started is performed, the consumption flow rate of the engine temporarily increases, and the fuel pressure in the downstream side fuel passage 36 cannot be covered only by the fuel supply by the secondary pump 20. May decrease rapidly. Therefore, immediately after the engine is started, the primary pump 10 is also driven (S106). Thereby, it can suppress that the fuel pressure of the downstream fuel path 36 falls from 350 kPa. In the present embodiment, since the check valve 40 is provided in the fuel passage, the check valve 40 is only provided when the fuel pressure in the downstream fuel passage 36 falls below the pressure in the fuel passage in the upstream fuel passage 35. Is opened, and fuel is supplied from the primary pump 10 side.

  Immediately after the engine is started (S102: YES), and after shifting to the idle state (S103: YES), since the flow rate of the engine is small, the driving of the primary pump 10 is stopped (S107), and the secondary pump 20 Continue driving. As described above, since the secondary pump 20 has a low discharge performance, the high pressure can be maintained with a small flow rate.

  Further, during normal running when the engine operating state is not a high load state (S109: YES), since the consumption flow of the engine is small, the driving of the first pump is stopped (S110) and the secondary pump 20 is driven to the engine. Fuel is supplied (S111, S112: YES). Since the secondary pump 20 of the present embodiment has low discharge performance, the fuel pressure in the downstream fuel passage 36 decreases with fuel consumption in the engine, and the fuel pressure in the downstream fuel passage 36 changes in a low region. Note that the consumption flow rate of the engine varies depending on the operating state. Further, the fuel pressure in the downstream fuel passage 36 fluctuates in a fuel pressure region lower than 350 kPa along with a change in the consumption flow rate of the engine.

  In the present embodiment, a high-pressure supply pump 50 is provided on the upstream side of the delivery pipe 55. Since the high-pressure supply pump 50 can increase the discharge pressure if the necessary flow rate is supplied, the downstream fuel passage can be obtained by using the secondary pump 20 having a low discharge performance during normal traveling with a low engine consumption flow rate. The fuel pressure of 36 is kept low. Thereby, pump load can be reduced and fuel consumption can be improved. Moreover, since the brushless motor is employ | adopted as a motor of the drive source of the secondary pump 20, control in a low rotation area is easy, and it can control in the state which suppressed the discharge amount from the secondary pump 20 low. It should be noted that during normal driving with a small consumption flow rate of the engine, the high pressure supply pump 50 has a small number of revolutions, and therefore does not bite the vapor.

  When the operating state of the engine is a high load (S109: YES), the driving of the secondary pump 20 is stopped (S116), and the primary pump 10 having a high discharge performance is driven (S117). During normal travel, the pressure in the downstream fuel passage 36 changes in a region lower than 350 kPa. Therefore, when the primary pump 10 is driven from the normal travel state to a high load state, the check valve 40 is opened. The fuel is supplied to the high-pressure supply pump 50 from the primary pump 10 side. Further, since the pressure of the fuel discharged from the primary pump 10 is adjusted by the first control valve 15 to be 350 kPa, the inlet pressure of the high-pressure supply pump 50 is maintained at about 350 kPa, and the high-pressure supply pump 50 It is possible to prevent vapor from being generated inside.

  When the engine operating state returns to the normal running state (S109: NO), the driving of the primary pump 10 is stopped (S110), the secondary pump 20 is driven again (S111, S112: YES), and the fuel is supplied by the secondary pump 20 Switch to. Further, when the vehicle speed becomes substantially zero at the end of traveling, the consumption flow rate of the engine decreases, and accordingly, the fuel pressure in the downstream fuel passage 36 increases to 520 kPa. And when an engine stops (S113: YES), the drive of the secondary pump 20 is stopped (S114). At this time, the fuel pressure in the downstream fuel passage 36 is maintained at 520 kPa. For this reason, even if the fuel pressure in the downstream fuel passage gradually decreases while the engine is stopped, the high pressure supply pump 50 maintains the pressure sufficiently higher than 350 kPa at which vapor is generated.

  Further, when an abnormality occurs in the secondary pump 20 (S101: YES), fuel is supplied by the primary pump 10. In this case, although the fuel pressure in the downstream fuel passage 36 cannot be made variable, the fuel pressure in the downstream fuel passage 36 is set to the high-pressure supply as in the conventional fuel supply device indicated by the one-dot chain line in FIG. Even when the pump 50 is rotating at a high speed, the operation can be continued while maintaining the pressure at about 350 kPa, which is a pressure at which no vapor is generated inside.

  As described above in detail, in the fuel supply device 1, the primary pump 10 discharges fuel to the outside of the fuel tank 5 via the fuel passage 31. The fuel discharged from the primary pump 10 is adjusted by the first control valve 15 so as to be equal to or lower than the first pressure value. The secondary pump 20 discharges fuel to the outside of the fuel tank 5 via the discharge passage 33 and the fuel passage 31 communicating with the fuel passage 31 on the downstream side of the check valve 40. The fuel discharged from the secondary pump 20 is adjusted by the second control valve 25 so as to be equal to or lower than the second pressure value higher than the first pressure value. Thereby, the pressure of the fuel supplied to the outside of the fuel tank 5 via the fuel passage 31 and the discharge passage 33 can be made variable. In this embodiment, since the primary pump 10 and the secondary pump 20 use pumps having different discharge performances, the fuel pressure to be supplied can be made variable while suppressing an increase in pump load.

  The fuel pressure in the downstream fuel passage 36 that is downstream of the check valve 40 can be maintained higher than the fuel pressure in the upstream fuel passage 35 that is upstream of the check valve 40. As a result, even if the pressure in the fuel passage gradually decreases due to engine stoppage or the like, the fuel pressure in the downstream fuel passage 36 is kept relatively high, so that the generation of vapor in the downstream fuel passage 36 is suppressed. Can do. In particular, in the present embodiment, the fuel in the downstream fuel passage 36 is supplied to the high-pressure supply pump 50. Therefore, by keeping the fuel pressure in the downstream fuel passage 36 relatively high, The occurrence of paper is suppressed, and the pressure can be reliably increased.

Further, the maximum discharge amount that can be discharged by the primary pump 10 is larger than the maximum discharge amount that can be discharged by the secondary pump 20. In the present embodiment, the fuel pressure is kept low by driving the secondary pump 20 having a low discharge performance when the required discharge amount is small, such as during normal operation or idling when the engine is not in a high load state. As a result, the pump load is reduced, which in turn contributes to improved fuel efficiency. Further, when the required discharge amount is large, the required amount of fuel can be discharged by driving the primary pump 10 having high discharge performance.
Furthermore, since a pump with low discharge performance is used as the secondary pump 20 that supplies fuel to the downstream fuel passage 36 held at a high pressure, the high pressure can be maintained with a small flow rate.

  Moreover, in this embodiment, the high pressure supply pump 50 which pressurizes and feeds the fuel supplied from the primary pump 10 and the secondary pump 20 is provided. Since the fuel can be pressurized by the high-pressure supply pump 50, precise control of the fuel pressure upstream of the high-pressure supply pump 50 is not necessary. In particular, during normal operation, the fuel pressure on the upstream side of the high-pressure supply pump 50 can be kept low, which reduces the pump load and contributes to improved fuel efficiency. In the present embodiment, since the primary pump 10 is driven and fuel is supplied during high load operation, the first pressure value controlled by the first control valve 15 is such that the rotation speed of the high-pressure supply pump 50 is large. The pressure is set so as not to generate paper when it becomes. Thereby, even when the rotation speed of the high-pressure supply pump 50 is increased, the generation of vapor inside the high-pressure supply pump 50 can be suppressed.

  The fuel filter 45 is provided between the primary pump 10 and the first control valve 15. Since the upstream fuel passage 35 upstream of the check valve 40 is controlled to a lower pressure than the downstream fuel passage 36, a fuel filter having a lower pressure resistance than that provided in the downstream fuel passage 36 is used. Can be used.

  The secondary pump 20 is a brushless motor as a drive source motor. In the present embodiment, fuel is supplied by the secondary pump 20 except during high-load operation. By adopting a brushless motor having a longer motor life as a drive source of the secondary pump 20 having a longer drive time than the primary pump 10, the durability of the entire apparatus is improved. In addition, the entire apparatus can be reduced in size. Furthermore, since the brushless motor can be easily controlled in the low rotation range, it can be controlled with the discharge amount from the secondary pump 20 kept low.

  Moreover, in this embodiment, the drive of the primary pump 10 and the secondary pump is controlled based on the driving | running state of an engine. Hereinafter, the effect of the control processing by the ECU 60 will be described.

  Further, when the engine operating state is a normal operating state or an idle state (S109: YES, S103: YES in FIG. 2), the driving of the primary pump 10 is stopped (S107, S110), and the secondary pump 20 is driven. (S111, S112: YES). As a result, during normal operation or idling when the flow rate of the engine is low, fuel pressure can be kept low by supplying fuel with the secondary pump 20 having a low discharge performance, so that the pump load is reduced, and consequently fuel consumption is reduced. Contributes to improvement.

  When it is determined that the engine operating state is a high load state (S109: YES), the relay 64 is turned off to stop the driving of the secondary pump 20 (S116), and the primary pump 10 is controlled to be driven (S116). S117). Thereby, at the time of high load operation with a large consumption flow rate in the engine, the required amount of fuel can be supplied by supplying fuel with the primary pump 10 having high discharge performance.

  Further, immediately after the engine is started (S102: YES, S103: YES), the primary pump 10 and the secondary pump 20 are controlled to be driven (S104, S105: YES, S106). As a result, even if the consumption flow rate of the engine temporarily increases due to the control for increasing the fuel injection amount immediately after the engine is started, the fuel pressure can be reduced by driving the primary pump 10 and the secondary pump 20. A sudden drop can be suppressed. Further, by driving the primary pump 10 having a high discharge performance, even when the voltage of the battery 62 is lowered, the primary pump 10 can supply the engine with an amount of fuel necessary for starting even at a low voltage. This makes it easier to start the engine.

  Furthermore, when it is determined that the second pump cannot be driven (S105: NO or S112: NO, S118, S101: YES), the primary pump is driven regardless of the operating state of the engine (S120). Thereby, even if it is a case where the secondary pump 20 cannot be driven, fuel supply can be continued.

  The ECU 60 constitutes “pump control means” and “abnormality judgment means”. Further, S104, S106, S107, S110, S111, S114, S116, S117, S119, S120, and S122 in FIG. It corresponds to processing as a function of “means”.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the structure substantially the same as 1st Embodiment, and description is abbreviate | omitted.
In the fuel supply device 2 according to the second embodiment, a fuel filter 46 is provided at a junction between the secondary pump 20 and the second control valve 25 where the fuel passage 31 and the discharge passage 33 join. . Thereby, since the foreign matter in the fuel discharged from the primary pump 10 and the foreign matter in the fuel discharged from the secondary pump 20 can be removed by the single fuel filter 46, the number of parts can be reduced. When the fuel filter 46 is provided between the secondary pump 20 and the second control valve 25 as in the present embodiment, the suction filter 48 removes relatively large foreign matters in the fuel, like the suction filter 47. A filter having a relatively low filtration accuracy may be employed.

(Other embodiments)
In the above embodiment, the fuel supply apparatus is applied to a four-cylinder direct injection engine. Other embodiments may be applied to port injection engines. When applied to a port injection engine, fuel that is maintained at a relatively high pressure downstream of the check valve can be supplied to the injector when the engine is restarted. Unburned HC can be reduced, and emission can be suppressed. The number of cylinders is not limited to four.
Moreover, in the said embodiment, it was what was called a returnless system which is not provided with the return piping which returns the surplus fuel in a delivery pipe to a fuel tank. In another embodiment, a return passage for returning surplus fuel in the delivery pipe to the fuel tank may be provided.

  In the above embodiment, the primary pump is a DC motor with a brush, and the secondary pump is a brushless motor. In other embodiments, the primary pump and the secondary pump may both be brushless motors. By adopting a brushless motor, the life of the motor is extended and the entire apparatus can be miniaturized. The secondary pump may be a DC motor with a brush.

Moreover, in the said embodiment, the primary pump and the secondary pump were arrange | positioned inside the fuel tank. In other embodiments, at least one of the primary pump and the secondary pump may be outside the fuel tank.
As mentioned above, this invention is not limited to the said embodiment at all, In the range which does not deviate from the meaning of invention, it can implement with a various form.

DESCRIPTION OF SYMBOLS 1 ... Fuel supply apparatus 5 ... Fuel tank 10 ... Primary pump (1st pump)
15 ... First control valve 20 ... Secondary pump (second pump)
25 ... Second control valve 30 ... Fuel passage member 31 ... Fuel passage 32 ... Discharge passage member 33 ... Discharge passage 40 ... Check valve 45 ... Fuel filter 46 ..Fuel filter 50 ... High pressure supply pump 55 ... Delivery pipe 56 ... Injector 60 ... ECU (control unit)

Claims (11)

A fuel passage member having a fuel passage for sending fuel stored in the fuel tank to the outside of the fuel tank;
A first pump that discharges fuel stored in the fuel tank to the fuel passage;
A first control valve that adjusts the pressure of the fuel discharged by the first pump to be equal to or lower than a first pressure value;
A check valve provided in the fuel passage for preventing the backflow of fuel upstream;
A discharge passage member having a discharge passage communicating with the fuel passage on the downstream side of the check valve;
A second pump for discharging the fuel stored in the fuel tank to the discharge passage;
A second control valve that adjusts the pressure of the fuel discharged by the second pump to be equal to or lower than a second pressure value higher than the first pressure value;
A fuel supply device comprising:   2. The fuel supply device according to claim 1, wherein a maximum discharge amount that can be discharged by the first pump is larger than a maximum discharge amount that can be discharged by the second pump.   3. The fuel supply apparatus according to claim 1, further comprising a high-pressure supply pump that pressurizes and feeds fuel supplied from the first pump and the second pump via the fuel passage. 4. .   The fuel supply device according to any one of claims 1 to 3, further comprising a fuel filter between the first pump and the first control valve.   The fuel supply device according to any one of claims 1 to 4, further comprising a fuel filter between the second pump and the second control valve.   The fuel supply device according to any one of claims 1 to 5, further comprising a fuel filter at a junction where the fuel passage and the discharge passage merge.   The fuel supply device according to claim 1, wherein at least one of the first pump and the second pump is a brushless motor.   The control part which has a pump control means which controls the drive of a said 1st pump and a said 2nd pump based on the driving | running state of an internal combustion engine is provided. Fuel supply system. The pump control means includes
When the operating state of the internal combustion engine is a high load operating state, control to drive the first pump,
9. The fuel supply device according to claim 8, wherein when the operation state of the internal combustion engine is a normal operation state or an idle state, the second pump is controlled to be driven.   10. The fuel supply device according to claim 8, wherein the pump control unit controls to drive the first pump and the second pump when the internal combustion engine is immediately after starting. 10. . The control unit includes abnormality determination means for determining whether the second pump can be driven,
The pump control means controls to drive the first pump regardless of the operating state of the internal combustion engine when the abnormality judging means judges that the second pump cannot be driven. The fuel supply device according to any one of claims 8 to 10.

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