JP6946980B2 - Fuel supply device and control method of fuel supply device - Google Patents

Description

The present invention relates to a fuel supply device and a method for controlling the fuel supply device.

In a fuel supply system that supplies liquid fuel to a fuel cell or the like, the liquid fuel may freeze due to the influence of the outside temperature in a cold region or the like. When the liquid fuel freezes, not only the pump lock state is caused, but also the pump may be damaged due to volume expansion, or the motor may be burnt due to energization in the pump lock state, which is a problem.

Here, there is known a technique for determining whether or not the cause of the pump lock state is due to freezing of the liquid fuel from the detected temperature of the liquid fuel (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-190169

However, with the technique disclosed in Patent Document 1, although the cause of the pump lock state can be identified, the cause of the pump lock state itself cannot be avoided.

An object of the present invention is to provide a technique for avoiding a pump lock caused by freezing of a liquid fuel.

The fuel supply device according to one aspect of the present invention includes a power unit to which liquid fuel is supplied to generate energy, a fuel tank in which liquid fuel is stored, and a fuel pump arranged in the fuel tank to supply liquid fuel to the power unit. , A sub-tank arranged in the fuel tank and accommodating the fuel pump, a fuel transfer means for transferring the liquid fuel in the fuel tank into the sub-tank, and discharging the liquid fuel in the sub-tank into the fuel tank outside the sub-tank. A fuel supply path that connects the fuel discharge means, the power unit, and the fuel pump to serve as a flow path for the liquid fuel supplied from the fuel pump, and a circulation path that branches off from the fuel supply path and circulates the liquid fuel in the sub tank. And are configured to include. The fuel transfer means is a jet pump, and is arranged so as to communicate with the inside and outside of the sub tank at the end of the circulation path in the sub tank. The fuel discharge means is a fuel discharge path that branches off from the circulation path and is configured to be able to discharge liquid fuel into the fuel tank outside the sub tank. The fuel discharge means further includes a circulation path and a switching valve configured to switch the fuel discharge path. The switching valve is a bimetal valve configured so that the flow path can be switched according to the temperature of the liquid fuel.

According to the present invention, the liquid fuel in the sub-tank in which the fuel pump is housed can be discharged to the outside of the sub-tank, so that problems such as pump lock caused by freezing of the liquid fuel around the fuel pump can be avoided. Can be done.

FIG. 1 is a schematic configuration diagram showing a main configuration of the fuel supply device of the first embodiment. FIG. 2 is a flowchart showing the fuel emission control of the first embodiment. FIG. 3 is a schematic configuration diagram showing a main configuration of a modification 1 of the first embodiment. FIG. 4 is a diagram for explaining the details of the branch point between the fuel supply path and the circulation path of the first modification. FIG. 5 is a flowchart showing the fuel emission control of the second modification. FIG. 6 is a flowchart showing the fuel emission control of the modified example 3. FIG. 7 is a diagram illustrating fuel discharge control of the fuel supply device of the second embodiment. FIG. 8 is a diagram illustrating fuel discharge control of the fuel supply device of the third embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

− First Embodiment −
FIG. 1 is a schematic configuration diagram showing a main configuration of the fuel supply device 100 of the first embodiment. As shown in FIG. 1, the fuel supply device 100 includes a power unit 10, a fuel pump 1, a sub tank 20, a fuel storage unit (fuel tank, main tank) 30, a fuel supply path 12, a circulation path 13, and fuel. A discharge path 14, a switching valve 2, and an auxiliary pump 3 are included to supply liquid fuel to the fuel injection device 11 included in the power unit 10. The fuel supply device 100 described below is applied to, for example, a fuel cell that consumes liquid fuel and a vehicle equipped with an internal combustion engine. The fuel cell does not need to be limited in its mode as long as it directly or indirectly consumes the liquid fuel. For example, a solid oxide fuel cell (SOFC) or a solid polymer fuel cell. Batteries (PEFC; Polymer Electrolyte Fuel Cell), etc.

The power unit 10 of the present embodiment is an internal combustion engine (engine) and converts liquid fuel into energy. More specifically, the power unit 10 generates energy by supplying the liquid fuel stored in the fuel storage unit 30 or the sub tank 20 and burning the liquid fuel injected in the form of a mist by the fuel injection device 11 provided. Let me. Since the fuel supply device 100 of the present embodiment is applied to the vehicle, the energy becomes the driving force of the vehicle.

The fuel storage unit 30 (hereinafter, also referred to as “fuel tank 30”) stores the liquid fuel supplied to the power unit 10. The fuel tank 30 may be a general container for storing flammable liquid fuel, and is a tank made of steel plate or resin. The fuel tank 30 is connected to the power unit 10 via the fuel supply path 12. The internal configuration of the fuel tank 30 will be described later.

The sub tank 20 (hereinafter, also referred to as “chamber 20”) is a container arranged in the fuel storage unit 30 and houses the fuel pump 1. The liquid fuel stored in the fuel tank 30 is transferred into the chamber 20 by the auxiliary pump 3 described later. That is, the chamber 20 is a so-called buffer fuel fuel tank (fuel chamber). The chamber 20 may also be made of steel plate or resin as a material as long as it is equivalent to a general container for storing liquid fuel.

The fuel pump 1 is a pump arranged in the chamber 20 and is connected to the fuel supply path 12. The fuel pump 1 supplies liquid fuel to the fuel injection device 11 of the power unit 10 via the fuel supply path 12. Specifically, the fuel pump 1 pumps the liquid fuel in the chamber 20 (see arrow 1a) and pumps the liquid fuel pumped through the fuel supply path 12 to the power unit 10.

The fuel supply path 12 is a pipe that serves as a flow path when the liquid fuel stored in the chamber 20 is supplied to the power unit 10. From the fuel supply path 12, a circulation path 13 serving as a flow path for circulating the liquid fuel pumped from the fuel pump 1 into the chamber 20 is provided separately from the flow path for supplying the liquid fuel to the power unit 10. Branch.

The circulation path 13 is a pipe that serves as a flow path for circulating the liquid fuel in the chamber 20. In the circulation path 13, the end opposite to the branch point with the fuel supply path 12 is configured to be arranged in the chamber 20. An auxiliary pump 3 is provided at the end. From the circulation path 13, a discharge path 14 for discharging the liquid fuel in the chamber 20 or the fuel pump 1 to the outside of the chamber 20 branches.

The auxiliary pump 3 functions as a fuel transfer means for transferring the liquid fuel stored outside the chamber 20 in the fuel tank 30 into the chamber 20. Therefore, the auxiliary pump 3 is configured such that the suction port is located outside the chamber 20 and the discharge port is located inside the chamber 20. The auxiliary pump 3 has a suction port on the lower side (lower side in the direction of gravity) at least on the side surface of the chamber 20 so that the liquid fuel stored in the fuel tank 30 can be transferred into the chamber 20 to the end. It is preferably located in.

The auxiliary pump 3 of this embodiment is a jet pump. Therefore, the jet pump provided at the end of the circulation path 13 utilizes the negative pressure generated when the liquid fuel is discharged from the circulation path 13 through the jet pump into the chamber 20 to fuel the fuel. The liquid fuel in the tank 30 is transferred into the chamber 20. With the chamber 20 configured in this way, the inside of the chamber 20 can be filled with the liquid fuel (buffer fuel) as long as sufficient liquid fuel exceeding the capacity of the chamber 20 is stored in the fuel tank 30.

The discharge passage 14 is a pipe that serves as a flow path for discharging the liquid fuel in the chamber 20 or the fuel pump 1 to the outside of the chamber 20, and functions as the fuel discharge means of the present embodiment. The discharge passage 14 of the present embodiment is provided as a branch from the circulation passage 13 as described above, and the end on the opposite side of the branch point is configured to be located in the outer region of the chamber 20 in the fuel tank 30. NS. Further, a switching valve 2 is arranged at a branch point between the discharge path 14 and the circulation path 13.

The switching valve 2 of this embodiment is a three-way valve. By appropriately selecting the valve opening direction of the switching valve 2, the flow path branched from the fuel supply path 12 circulates the liquid fuel pumped from the fuel pump 1 into the chamber 20 via the circulation path 13. It is possible to switch between the flow path (return line 13a) and the flow path (discharge line 14a) for discharging the fuel to the outside of the chamber 20 via the discharge path 14.

The switching valve 2 may be composed of a bimetal valve. In this case, the switching valve 2 does not need to be controlled to open / close by the controller 50 described later, and the temperature of the liquid fuel in the chamber 20 or passing through the circulation path 13 becomes equal to or lower than a preset predetermined temperature. In this case, the valve opening / closing is controlled by the characteristics of the bimetal, and the return line 13a and the discharge line 14a can be passively switched. The "predetermined temperature" here may be the same as the "predetermined temperature" according to step S2 in the flowchart of FIG. 2, which will be described later.

The controller 50 is composed of, for example, a central arithmetic unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 50 is configured to be communicable with at least the fuel pump 1 and the switching valve 2, and controls these operations, specifically, the movement / stop of the fuel pump 1 and the opening / closing of the switching valve 2. ..

The above is the basic configuration of the fuel supply device 100 of the present embodiment. When the fuel supply device 100 includes the above-described configuration, particularly the discharge path 14 as the fuel discharge means, the liquid fuel in the fuel pump 1 or around the fuel pump 1 freezes due to the influence of the outside temperature in a cold region or the like. Can be avoided. As a result, it is possible to prevent the liquid fuel from freezing and locking the fuel pump 1 (pump lock). In addition, it is possible to avoid the possibility of damaging the pump due to the freezing of the liquid fuel and the expansion of its volume. More specifically, it is possible to avoid the possibility of damaging the fuel pump 1 from the inside due to the freezing and expansion of the liquid fuel in the fuel pump 1. Further, it is possible to avoid the possibility that the liquid fuel around the fuel pump 1 freezes and expands, so that the fuel pump 1 is crushed from the outside and damaged.

Hereinafter, a method of avoiding freezing of the liquid fuel in or around the fuel pump 1 by using the above configuration will be described. In the following, the freezing of the liquid fuel in the fuel pump 1 or around the fuel pump 1 is also referred to as "fuel freezing" in one word.

FIG. 2 is a flowchart showing a flow of control (fuel discharge control) when the fuel supply device 100 of the present embodiment avoids fuel freezing. The controller 50 included in the fuel supply device 100 is programmed to perform the controls described below. Further, the fuel supply device 100 detects or estimates the fuel temperature detecting means for detecting the temperature (fuel temperature) of the liquid fuel in the chamber 20 and the amount of liquid fuel in the fuel pump 1 and the chamber 20. It is equipped with a means for obtaining the amount of residual fuel.

In step S1, the controller 50 acquires the temperature of the liquid fuel in the chamber 20 from the fuel temperature detecting means. The fuel temperature detecting means of the present embodiment is a known temperature sensor (not shown), which is provided, for example, in the lower inside of the chamber 20 and is configured to be able to transmit the detected fuel temperature to the controller 50.

In step S2, the controller 50 determines whether or not the fuel temperature acquired in step S1 is equal to or lower than a predetermined temperature. The "predetermined temperature" is a temperature higher than the freezing point of the liquid fuel, and if the temperature is lower than the freezing point of the liquid fuel, it can be determined that the liquid fuel is likely to freeze. The "predetermined temperature" is appropriately set according to the type of liquid fuel. When the controller 50 determines that the acquired fuel temperature has become equal to or lower than a predetermined temperature, the controller 50 executes the subsequent process of step S3. When the acquired fuel temperature is higher than the predetermined temperature, the processes of steps S1 to S2 are repeatedly executed until the acquired fuel temperature is determined to be equal to or lower than the predetermined temperature.

In step S3, the controller 50 opens the switching valve 2 so that the discharge line 14a and the fuel supply path 12 communicate with each other in order to discharge the liquid fuel in the chamber 20 and the fuel pump 1 to the outside of the chamber 20. Control the direction. As a result, the liquid fuel pumped by the fuel pump 1 is discharged to the region outside the chamber 20 in the fuel tank 30. Further, since the opening direction of the switching valve 2 is controlled and the return line 13a that circulates the liquid fuel in the chamber 20 is shut off, the amount of liquid fuel circulated in the chamber 20 through the return line 13a becomes substantially zero. Therefore, the suction of liquid fuel from the outside of the chamber 20 by the auxiliary pump 3 (jet pump) is eliminated. As a result, the amount of liquid fuel around the fuel pump 1 or in the fuel pump 1 can be reduced. As a result, at least around the fuel pump 1, there is no liquid fuel in an amount sufficient to lock the fuel pump 1 due to volume expansion even if it freezes, so that the possibility that the fuel pump 1 is locked due to the fuel freeze is avoided. can do.

Here, when the auxiliary pump 3 is arranged as in the present embodiment, a general jet pump usually does not have a mechanism (structure) for blocking communication inside and outside the chamber 20. Therefore, even if the return line 13a is cut off, the liquid fuel in the fuel tank 30 may flow in through the jet pump. However, the amount of liquid fuel that flows in in this way is small, and as long as the fuel pump 1 is driven, the amount of liquid fuel that has flowed in can be discharged to the outside of the chamber 20 as it is or in a larger amount. Therefore, in principle, the inflowing liquid fuel does not accumulate enough to cover the periphery of the fuel pump 1. Therefore, even if the jet pump does not have a mechanism (structure) for blocking communication inside and outside the chamber 20, it is possible to avoid the possibility that the fuel pump 1 will be locked due to fuel freezing as described above.

However, the jet pump of the present embodiment may further include a mechanism (structure) for blocking communication inside and outside the chamber 20, for example, an on-off valve, in order to prevent the liquid fuel from flowing into the chamber 20 via the jet pump. good. As a result, after the return line 13a is cut off in step S3, the amount of liquid fuel in the fuel pump 1 and around the fuel pump 1 can be reduced more efficiently.

Further, although not shown in the flowchart of FIG. 2, it is desirable to stop the system of the power unit 10 before executing the process of step S3. Specifically, it is desirable to stop the operation of the fuel injection device 11. As a result, the fuel injection device 11 operates in a state where the amount of liquid fuel in the chamber 20 and the fuel pump 1 is exhausted, so that the fuel injection device 11 (injector) is broken due to so-called empty heating. Can be prevented.

In step S4, the remaining fuel amount acquisition means acquires the remaining fuel amount in the chamber 20. The remaining fuel amount acquisition means of the present embodiment is a functional unit of the controller 50, and estimates the remaining fuel amount in the chamber 20 as follows.

The capacity in the chamber 20 can be estimated at least based on the elapsed time (discharge line communication duration) after the flow path branching from the fuel supply path 12 is switched to the discharge line 14a in step S3. Specifically, it can be estimated as follows. First, the volume inside the chamber 20 and the fuel pump 1 and the discharge amount per rotation of the fuel pump 1 can be known in advance from the design values and the like. Further, in the vehicle system, the rotation speed of the fuel pump 1 may be driven at a constant value. Therefore, when the rotation speed of the fuel pump 1 is set to a constant value, the set rotation speed can be known in advance. ..

That is, if the elapsed time after switching to the discharge line 14a is known, the liquid fuel discharged from the chamber 20 during the elapsed time is multiplied by the number of rotations of the fuel pump 1 and the discharge amount per rotation. The amount can be calculated. Then, since the liquid fuel is normally fully stored in the chamber 20, the above-mentioned amount of liquid fuel calculated from the maximum amount of liquid fuel in the chamber 20 and the fuel tank 30 that can be derived from the design value or the like is obtained. The amount of residual liquid fuel can be estimated by subtracting. If the rotation speed of the fuel pump 1 is not a constant value, the controller 50 may acquire the rotation speed of the fuel pump 1 during the discharge line communication duration from a command value or the like instructing the drive of the fuel pump 1.

Since the discharge amount per rotation of the fuel pump 1 changes depending on the temperature, pressure, viscosity, etc. of the liquid fuel, the remaining fuel amount may be estimated (corrected) in consideration of these values. By considering at least one of these values, a more accurate residual fuel amount can be estimated. The amount of remaining fuel is not estimated as described above, and a general liquid amount meter (sensor for measuring the amount of liquid) is arranged in the chamber 20 as a means for acquiring the amount of remaining fuel separately from the controller 50 to obtain the amount of liquid. The controller 50 may be configured to acquire the remaining fuel amount detected by the meter.

In step S5, the controller 50 determines whether or not the amount of remaining fuel estimated in step S3 is equal to or less than a predetermined amount. The "predetermined amount" here is predetermined from the viewpoint of the failure risk of the fuel pump 1 and the viewpoint of suppressing power consumption. For example, since foreign matter that may accumulate at the bottom of the chamber 20 may be pumped up, an amount that can be determined to avoid the risk of damage due to the fuel pump 1 biting the foreign matter is set to a predetermined amount. Alternatively, the amount at which it is determined that the fuel pump 1 is not likely to be damaged even if the liquid fuel remaining in the chamber 20 freezes is set to a predetermined amount. When the amount of remaining fuel becomes less than or equal to the "predetermined amount", the fuel pump 1 can be stopped to eliminate the risk of damage to the fuel pump 1, and the fuel pump 1 is not excessively operated. The amount of consumption can be suppressed.

In step S5, when the amount of remaining fuel estimated in step S3 is equal to or less than a predetermined amount, the processing of the following step S6 is executed. When the amount of residual fuel is larger than the predetermined amount, the processes of steps S4 to S5 are repeatedly executed until the amount of residual fuel becomes equal to or less than the predetermined amount.

In step S6, the controller 50 stops the fuel pump 1. As a result, there is only a smaller amount of liquid fuel in the vicinity of the fuel pump 1 and in the fuel pump 1 than the amount of liquid fuel that may lock the fuel pump 1 due to the fuel freezing, which is caused by the fuel freezing. Conventional problems can be avoided in advance.

The above is the details of the fuel emission control executed by the controller 50 included in the fuel supply device 100 of the first embodiment. Hereinafter, a modified example of the present embodiment will be described.

<Modification example 1>
The fuel supply device 200 of the first modification is different from the fuel supply device 100 in the branch position where the circulation path 13 branches from the fuel supply path 12.

FIG. 3 is a schematic configuration diagram of the fuel supply device 200. As shown in the figure, the branch point between the circulation path 13 and the fuel supply path 12 in this example is located in the fuel injection device 11, and the circulation path 13 branches from the fuel supply path 12 outside the fuel tank 30. At the same time, its end is configured to be located in the chamber 20 in the fuel tank 30.

FIG. 4 is a schematic configuration diagram of the fuel supply device 200, and is a diagram for explaining the branch position between the fuel supply path 12 and the circulation path 13 in more detail. In the fuel injection device 11, the section indicated by the double-headed arrow in the figure is an injector rail that supplies liquid fuel to the injector 11a included in the fuel injection device 11. However, in FIG. 4, the joint portion between the injector rail and the injector 11a is omitted.

As shown by the shaded area in the figure, the fuel supply path 12 in this example includes an injector rail included in the fuel injection device 11. Then, the circulation path 13 in this example branches at the terminal position of the injector rail in the fuel supply path 12 when viewed from the fuel pump 1 side. That is, the circulation path 13 in this example is configured to branch from the injector rail end of the fuel supply path 12 so that the end on the opposite side of the branch point is located in the chamber 20.

<Modification 2>
Modification 2 shows another example of the above-mentioned fuel emission control. FIG. 5 is a flowchart showing the fuel emission control according to the modified example 2. This example is characterized in that fuel emission control is executed when the power unit 10 is stopped. Specifically, step S11 described below is characterized, and subsequent steps S3 to S6 are the same as the above-described flow described with reference to FIG.

In step S11, the controller 50 determines whether or not the system of the power unit 10 is stopped. Specifically, it is determined whether or not the fuel injection by the fuel injection device 11 is stopped. For example, it can be determined from the presence or absence of a drive instruction to the power unit 10 or a fuel injection instruction to the fuel injection device 11. When the controller 50 determines that the system of the power unit 10 is stopped, the controller 50 executes the processes of steps S3 to S6 in the same manner as described with reference to the flowchart of FIG. 2 described above. If it is determined that the system of the power unit 10 is not stopped, the process of step S1 is repeatedly executed until the system is stopped.

As described above, according to the second modification, when the system of the power unit 10 is stopped without considering the temperature of the liquid fuel in the chamber 20, the liquid fuel in the fuel pump 1 and the chamber 20 is moved out of the chamber 20. Discharge. Even with such a control mode, it is possible to avoid the possibility that the fuel pump 1 will be locked due to fuel freezing, as in the above-described embodiment.

<Modification example 3>
Modification 3 shows another example of fuel emission control described above (first embodiment and modification 2). FIG. 6 is a flowchart showing the fuel emission control according to the modified example 3. This example is characterized in that the fuel emission control is executed during the system stop after the power unit 10 is stopped. Specifically, steps S21, 22, and 23 described below are characterized, and steps S1, S2, and steps S3 to S6 are the same as the above-described flow described with reference to FIG.

In step S21, the controller 50 determines whether or not the system of the power unit 10 is stopped as in step S11 of the second modification. If it is determined that the system of the power unit 10 is stopped, the process of step S22 is executed. If it is determined that the system of the power unit 10 is not stopped, the process of step S21 is repeatedly executed until the system is stopped.

In step S22, the controller 50 stops driving the fuel pump 1. Then, the controller 50 executes the processing of the subsequent step S1.

In steps S1 to S2, the temperature of the liquid fuel in the chamber 20 is detected in the same manner as described above, and it is determined whether or not the detected fuel temperature is equal to or lower than the “predetermined temperature”. If it is determined that the detected fuel temperature is equal to or lower than the predetermined temperature, the opening direction of the switching valve 2 is switched so that the discharge line 14a and the fuel supply path 12 communicate with each other in the following step S3, and then in the following step S23. The process is executed.

In step S23, the fuel pump 1 stopped in step S22 is driven to discharge the liquid fuel in the chamber 20 to the outside of the chamber 20. Even with such a control mode, it is possible to avoid the possibility that the fuel pump 1 will be locked due to fuel freezing, as in the above-described embodiment.

As described above, the fuel supply devices 100 and 200 of the first embodiment are arranged in the power unit 10 to which the liquid fuel is supplied and emits energy, the fuel tank 30 in which the liquid fuel is stored, and the fuel tank 30, and the liquid fuel is supplied. A fuel pump 1 supplied to the power unit 10, a sub tank 20 arranged in the fuel tank 30 and accommodating the fuel pump 1, and a fuel transfer means (auxiliary pump 3) for transferring the liquid fuel in the fuel tank 30 into the sub tank 20. A fuel discharge means (fuel discharge path 14) for discharging the liquid fuel in the sub tank 20 into the fuel tank 30 outside the sub tank 20 is included. As a result, the liquid fuel remaining in the vicinity of the fuel pump 1 and in the fuel pump 1 can be eliminated, so that the liquid fuel in the fuel pump 1 or in the vicinity of the fuel pump 1 is affected by the influence of the outside temperature in a cold region or the like. Pump lock caused by freezing can be avoided.

Further, in the fuel supply devices 100 and 200 of the first embodiment, the fuel supply path 12 and the fuel supply path 12 which connect the power unit 10 and the fuel pump 1 and serve as a flow path for the liquid fuel supplied from the fuel pump 1 The jet pump as a fuel transfer means is arranged at the end of the circulation path 13 in the sub tank 20 and further includes a circulation path 13 for circulating the liquid fuel in the sub tank, and the fuel as the fuel discharge means. The discharge passage 14 is configured to branch from the circulation passage 13 so that liquid fuel can be discharged into the fuel tank 30 outside the sub tank 20. Further, the fuel discharge means of the fuel supply devices 100 and 200 of the first embodiment includes a flow path (return line 13a) for circulating the liquid fuel in the sub tank 20 via the circulation path 13 and a fuel discharge path 14 for the liquid fuel. The switching valve 2 is provided so as to be able to switch between the flow path (discharge line 14a) for discharging to the outside of the sub tank 20 via the sub tank 20. This makes it possible to realize an example of specific fuel supply devices 100 and 200 that execute fuel emission control.

Further, according to the fuel supply devices 100 and 200, the switching valve 2 is a bimetal valve configured so that the flow path can be switched according to the temperature of the liquid fuel, whereby the temperature of the liquid fuel is set in advance. When the temperature falls below the above temperature, the valve opening / closing is controlled by the characteristics of the bimetal, so that the return line 13a and the discharge line 14a can be passively switched according to the fuel temperature.

Further, according to the fuel supply devices 100 and 200, the jet pump includes an on-off valve capable of preventing the liquid fuel in the fuel tank 30 from flowing into the sub tank 20 via the jet pump. As a result, after the return line 13a is cut off, the amount of liquid fuel flowing into the chamber 20 from outside the chamber 20 becomes substantially zero, so that the liquid fuel can be discharged out of the chamber 20 more efficiently.

Further, according to the fuel supply devices 100 and 200, the fuel discharging means discharges the liquid fuel after stopping the supply of the liquid fuel to the power unit 10. As a result, it is possible to eliminate the risk of damage to the fuel injection device 11 due to the operation of the power unit 10 in a state where the liquid fuel is not supplied.

Further, according to the fuel supply devices 100 and 200, a fuel temperature detecting means for detecting the temperature of the liquid fuel in the sub tank 20 is further provided, and the fuel discharging means is when the liquid fuel in the sub tank 20 reaches a predetermined temperature. In addition, the liquid fuel is discharged. As a result, the liquid fuel can be reliably discharged to the outside of the chamber 20 before the liquid fuel freezes.

Further, according to the fuel supply devices 100 and 200, a means for acquiring the remaining fuel amount for acquiring the amount of liquid fuel in the sub tank 20 is further provided, and when the amount of liquid fuel becomes equal to or less than a predetermined amount, the fuel pump is stopped. As a result, it is possible to avoid the risk of damage to the fuel pump 1 due to biting foreign matter and the like, and to suppress power consumption due to excessive operation of the fuel pump 1.

Further, according to the fuel supply devices 100 and 200, the remaining fuel amount acquisition means is the amount of liquid fuel at least from the elapsed time after the liquid fuel in the sub tank 20 is discharged by the fuel discharge means (discharge line communication duration). To estimate. As a result, it is not necessary to separately provide a means for acquiring the remaining fuel amount such as a liquid amount meter, so that the manufacturing cost can be reduced.

− Second embodiment −
FIG. 7 is a diagram for explaining the fuel supply device 300 according to the second embodiment. The fuel supply device 200 has a different configuration of the fuel discharge means from the first embodiment. The fuel discharging means of the present embodiment has a structure capable of tilting the fuel pump 1 and the chamber 20 by a predetermined angle or more in the fuel tank 30.

FIG. 7A shows a state in which, for example, the fuel pump 1 supplies fuel to the power unit 10 (not shown) in a normal state. Then, when the temperature of the liquid fuel drops and the fuel temperature becomes equal to or lower than the "predetermined temperature", the fuel supply device 200 is in the state shown in FIG. 7B. The "predetermined temperature" here is a temperature higher than the freezing point of the liquid fuel, and is equal to or lower than that of the first embodiment. The reason for this is that, as will be described later, according to the fuel supply device 300, even if the liquid fuel becomes a slurry, it can be discharged to the outside of the chamber 20.

FIG. 7B is a diagram for explaining a mode in which the fuel supply device 200 discharges the liquid fuel in the chamber 20 to the outside of the chamber 20. As shown in the figure, in the fuel supply device 200, the fuel pump 1 and the chamber 20 are tilted in the fuel tank 30 so that the liquid fuel in the chamber 20 is discharged until the amount becomes equal to or less than a “predetermined amount”. The "predetermined amount" here may be the same as or less than that of the first embodiment. The reason why it may be less than that is that since it is not necessary to operate the fuel pump 1 in this embodiment, there is no risk that the fuel pump 1 will be locked as described above and there is no risk that the power consumption will be excessive. Is. That is, the predetermined amount of this embodiment may be zero. Even with the fuel discharging means having such a configuration, the liquid fuel in the chamber 20 can be discharged, and the fuel freezing can be avoided as in the first embodiment.

Further, in the fuel supply device 200, since it is not necessary to move the fuel pump 1 when discharging the liquid fuel, even the slurry-like liquid fuel which is difficult to be pumped by the fuel pump 1 can be discharged to the outside of the chamber 20. can.

As shown in the figure, it is desirable that the fuel supply path 12 is connected by, for example, a rotary joint 4 so that the fuel supply path 12 is not damaged when the fuel pump 1 and the chamber 20 are tilted. Further, the fuel discharging means of the present embodiment can be realized by a wire for pulling up the fuel pump 1 and the chamber 20 upward, a servomotor for winding up the wire, and the like, and the specific configuration thereof is not particularly limited.

As described above, according to the fuel supply device 200 of the second embodiment, the fuel discharging means discharges the liquid fuel in the sub tank 20 by tilting the fuel pump 1 and the sub tank 20 by a predetermined angle or more in the fuel tank 30. Even with such a configuration, the liquid fuel in the chamber 20 can be discharged, and fuel freezing can be avoided as in the first embodiment.

− Third Embodiment −
FIG. 8 is a diagram for explaining the fuel supply device 300 according to the third embodiment. The fuel supply device 400 has a different fuel discharge means from the first and second embodiments. The fuel discharge means of the present embodiment has an openable opening (discharge valve 5) formed in the chamber 20 and a structure capable of moving the fuel pump 1 and the chamber 20 upward in the direction of gravity in the fuel tank 30. , Consists of.

FIG. 8A shows a state in which, for example, the fuel pump 1 supplies fuel to the power unit 10 (not shown) in a normal state. Then, when the temperature of the liquid fuel drops and the fuel temperature becomes equal to or lower than the "predetermined temperature", the fuel supply device 200 is in the state shown in FIG. 8B. The "predetermined temperature" here is the same as that of the second embodiment.

FIG. 8B is a diagram for explaining a mode in which the fuel supply device 400 discharges the liquid fuel in the chamber 20 to the outside of the chamber 20. As shown in the figure, in the fuel supply device 400, the fuel pump 1 and the chamber 20 are pulled upward in the fuel tank 30 until the amount of liquid fuel in the chamber 20 becomes "predetermined amount" or less. At this time, the discharge valve 5 is opened and is at a position higher than the liquid level of the liquid fuel in the fuel tank 30. The "predetermined amount" here is the same as that of the second embodiment. Even with such a configuration, since the liquid fuel in the chamber 20 can be discharged, fuel freezing can be avoided as in the second embodiment.

In the present embodiment, the amount of residual liquid fuel left in the chamber 20 can be adjusted by adjusting the high and low positions of the discharge valve 5 in the direction of gravity, but also in this example, the fuel is fueled during fuel discharge control. Since it is not necessary to drive the pump 1, it is preferable to provide the discharge valve 5 at a position continuous with the bottom surface of the chamber 20 so that all the liquid fuel in the chamber 20 can be discharged in the state of FIG. 8B. ..

Further, in the fuel supply device 300, as in the second embodiment, it is not necessary to move the fuel pump 1 when discharging the liquid fuel, so that even a slurry-like liquid fuel that is difficult to be pumped by the fuel pump 1 is a chamber. 20 can be discharged to the outside.

As shown in the figure, the fuel supply path 12 includes a hose-shaped portion 6 formed of an elastic and flexible structure, and the fuel supply path 12 is damaged when the fuel pump 1 and the chamber 20 are lifted. It is desirable that it is configured not to. Further, the fuel discharging means of the present embodiment can be realized by a wire for pulling up the fuel pump 1 and the chamber 20 upward, a servomotor for winding the wire, or the like, as in the second embodiment. Further, for example, a lift structure capable of lifting the fuel pump 1 and the chamber 20 from below may be arranged below the chamber 20, and the specific configuration thereof is not particularly limited.

As described above, according to the fuel supply device 300 of the third embodiment, the fuel discharge means has an openable / closable opening (discharge valve 5) formed in the sub tank 20, and the fuel tank 30 and the sub tank 20 in the fuel tank 30. By moving upward in the direction of gravity, the liquid fuel in the sub-tank is discharged from the opening. Even with such a configuration, the liquid fuel in the chamber 20 can be discharged, and fuel freezing can be avoided as in the first embodiment.

Although the embodiment of the present invention and its modification have been described above, the present invention is not limited to the above-described embodiment and its modification.

For example, the branch positions (arrangement of the switching valve 2) of the fuel supply path 12, the circulation path 13, and the discharge path 14 are not limited to the positions shown in FIG. As long as the fuel discharging means functions as described above, that is, the flow path of the liquid fuel pumped from the fuel pump 1 reaches the fuel injection device 11, the inside of the chamber 20, and the outside of the chamber 20 separately and selectively. As long as it is configured as, the mode may be changed as appropriate.

As described above, the above-described embodiment shows only a part of the application examples of the present invention, and does not mean that the technical scope of the present invention is limited to the specific configuration of the above-described embodiment. Further, the above-described embodiments and modifications can be appropriately combined as long as there is no contradiction.

1 ... Fuel pump 2 ... Switching valve 3 ... Fuel transfer means (auxiliary pump, jet pump)
10 ... Power unit 12 ... Fuel supply path 13 ... Circulation path 14 ... Fuel discharge path 20 ... Sub tank (chamber)
30 ... Fuel tank

Claims (9)

A power unit that is supplied with liquid fuel and emits energy,
A fuel tank in which the liquid fuel is stored and
A fuel pump arranged in the fuel tank and supplying the liquid fuel to the power unit,
A sub-tank arranged in the fuel tank and accommodating the fuel pump,
A fuel transfer means for transferring the liquid fuel in the fuel tank into the sub tank, and
A fuel discharging means for discharging the liquid fuel in the sub tank to the outside of the sub tank and into the fuel tank.
A fuel supply path that connects the power unit and the fuel pump and serves as a flow path for the liquid fuel supplied from the fuel pump.
It is provided with a circulation path that branches from the fuel supply path and circulates the liquid fuel in the sub tank.
The fuel transfer means is a jet pump, which is arranged so as to communicate with the inside and outside of the sub tank at the end of the circulation path in the sub tank.
The fuel discharge means is a fuel discharge path that is branched from the circulation path and is configured to be able to discharge the liquid fuel into the fuel tank outside the sub tank.
The fuel discharge means further includes a switching valve configured to switch between the circulation path and the fuel discharge path.
The switching valve is a bimetal valve configured so that the flow path can be switched according to the temperature of the liquid fuel.
A fuel supply device characterized by that. A power unit that is supplied with liquid fuel and emits energy,
A fuel tank in which the liquid fuel is stored and
A fuel pump arranged in the fuel tank and supplying the liquid fuel to the power unit,
A sub-tank arranged in the fuel tank and accommodating the fuel pump,
A fuel transfer means for transferring the liquid fuel in the fuel tank into the sub tank, and
A fuel discharging means for discharging the liquid fuel in the sub tank to the outside of the sub tank and into the fuel tank.
A fuel supply path that connects the power unit and the fuel pump and serves as a flow path for the liquid fuel supplied from the fuel pump.
It is provided with a circulation path that branches from the fuel supply path and circulates the liquid fuel in the sub tank.
The fuel transfer means is a jet pump, which is arranged so as to communicate with the inside and outside of the sub tank at the end of the circulation path in the sub tank.
The fuel discharge means is a fuel discharge path that is branched from the circulation path and is configured to be able to discharge the liquid fuel into the fuel tank outside the sub tank.
The jet pump includes an on-off valve capable of preventing the liquid fuel in the fuel tank from flowing into the sub tank via the jet pump.
A fuel supply device characterized by that. A power unit that is supplied with liquid fuel and emits energy,
A fuel tank in which the liquid fuel is stored and
A fuel pump arranged in the fuel tank and supplying the liquid fuel to the power unit,
A sub-tank arranged in the fuel tank and accommodating the fuel pump,
A fuel transfer means for transferring the liquid fuel in the fuel tank into the sub tank, and
A fuel discharging means for discharging the liquid fuel in the sub tank to the outside of the sub tank and into the fuel tank is provided.
The fuel discharging means discharges the liquid fuel in the sub tank by tilting the fuel pump and the sub tank by a predetermined angle or more in the fuel tank.
A fuel supply device characterized by that. A power unit that is supplied with liquid fuel and emits energy,
A fuel tank in which the liquid fuel is stored and
A fuel pump arranged in the fuel tank and supplying the liquid fuel to the power unit,
A sub-tank arranged in the fuel tank and accommodating the fuel pump,
A fuel transfer means for transferring the liquid fuel in the fuel tank into the sub tank, and
A fuel discharging means for discharging the liquid fuel in the sub tank to the outside of the sub tank and into the fuel tank is provided.
The fuel discharging means is
An openable opening formed in the sub tank and
By moving the fuel tank and the sub tank upward in the direction of gravity in the fuel tank, the liquid fuel in the sub tank is discharged from the opening.
A fuel supply device characterized by that. A power unit that is supplied with liquid fuel and emits energy,
A fuel tank in which the liquid fuel is stored and
A fuel pump arranged in the fuel tank and supplying the liquid fuel to the power unit,
A sub-tank arranged in the fuel tank and accommodating the fuel pump,
A fuel transfer means for transferring the liquid fuel in the fuel tank into the sub tank, and
A fuel discharging means for discharging the liquid fuel in the sub tank to the outside of the sub tank and into the fuel tank is provided.
The fuel discharging means discharges the liquid fuel after stopping the supply of the liquid fuel to the power unit.
A fuel supply device characterized by that. A power unit that is supplied with liquid fuel and emits energy,
A fuel tank in which the liquid fuel is stored and
A fuel pump arranged in the fuel tank and supplying the liquid fuel to the power unit,
A sub-tank arranged in the fuel tank and accommodating the fuel pump,
A fuel transfer means for transferring the liquid fuel in the fuel tank into the sub tank, and
A fuel discharging means for discharging the liquid fuel in the sub tank to the outside of the sub tank and into the fuel tank is provided.
A fuel temperature detecting means for detecting the temperature of the liquid fuel in the sub tank is further provided.
The fuel discharging means discharges the liquid fuel when the liquid fuel in the sub tank reaches a predetermined temperature.
A fuel supply device characterized by that. A power unit that is supplied with liquid fuel and emits energy,
A fuel tank in which the liquid fuel is stored and
A fuel pump arranged in the fuel tank and supplying the liquid fuel to the power unit,
A sub-tank arranged in the fuel tank and accommodating the fuel pump,
A fuel transfer means for transferring the liquid fuel in the fuel tank into the sub tank, and
A fuel discharging means for discharging the liquid fuel in the sub tank to the outside of the sub tank and into the fuel tank is provided.
Further provided with a residual fuel amount acquisition means for acquiring the amount of liquid fuel in the sub tank,
When the amount of the liquid fuel becomes equal to or less than a predetermined amount, the fuel pump is stopped.
A fuel supply device that features that. In the fuel supply device according to claim 7.
The remaining fuel amount acquisition means estimates the liquid fuel amount from at least the elapsed time from the discharge of the liquid fuel in the sub tank by the fuel discharge means.
A fuel supply device characterized by that. A power unit that is supplied with liquid fuel and emits energy,
A fuel tank in which the liquid fuel is stored and
A fuel pump arranged in the fuel tank and supplying the liquid fuel to the power unit,
A sub-tank arranged in the fuel tank and accommodating the fuel pump,
A fuel transfer means for transferring the liquid fuel in the fuel tank into the sub tank, and
A fuel discharging means for discharging the fuel in the sub tank to the outside of the sub tank and into the fuel tank.
A fuel supply path that connects the power unit and the fuel pump and serves as a flow path for the liquid fuel supplied from the fuel pump.
It is provided with a circulation path that branches from the fuel supply path and circulates the liquid fuel in the sub tank .
The fuel transfer means is a jet pump, which is arranged so as to communicate with the inside and outside of the sub tank at the end of the circulation path in the sub tank.
The fuel discharge means is a fuel discharge path that is branched from the circulation path and is configured to be able to discharge the liquid fuel into the fuel tank outside the sub tank.
The fuel discharge means further includes a switching valve configured to switch between the circulation path and the fuel discharge path.
The switching valve is a control method for a fuel supply device which is a bimetal valve configured to switch the flow path according to the temperature of the liquid fuel.
Under a predetermined condition, the fuel in the sub tank is discharged outside the sub tank and into the fuel tank.
A method of controlling a fuel supply device, which is characterized in that.

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