Fuel tank treatment device

Abstract

To provide a fuel tank treatment device capable of quickly reducing the pressure of a fuel tank while suppressing lock of a valve.SOLUTION: A fuel tank treatment device 11 mainly comprises a fuel tank 13, a first valve 14, a discharge passage 16, a second valve 17, and an arithmetic control section 18. The first valve 14 is disposed in the fuel tank 13 in which fuel 12 is stored. The discharge passage 16 communicates the first valve 14 with the outside and is configured so that gas 15 discharged from the fuel tank 13 flows. The second valve 17 is interposed in the discharge passage 16. The arithmetic control section 18 regulates an opening of the second valve 17 on the basis of a state change of the fuel tank 13 when the second valve 17 is opened.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fuel tank treatment device that reduces the internal pressure of a fuel tank during refueling. [Background technology]

[0002] In a vehicle that uses an engine as a power source, fuel to be supplied to the engine is stored in a fuel tank. Normally, the inside of the fuel tank is under high pressure due to evaporative gas, which is vaporized fuel. Therefore, when refueling, the inside of the fuel tank is depressurized by releasing gas from the inside of the fuel tank to the outside. In this way, when the fuel filler opening of the fuel tank is opened, it is possible to prevent fuel or evaporative gas from spraying out from the filler opening. An example of an invention for depressurizing a fuel tank when refueling is described in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-77422 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned invention leaves room for improvement in terms of effectively depressurizing the fuel tank during refueling.

[0005] Specifically, due to the structure of the open path through which evaporative gas flows to reduce the pressure, there was a problem that a certain waiting time was required for the fuel tank to be depressurized when refueling.

[0006] Furthermore, if the flow rate of the evaporated gas is set high in order to shorten the waiting time, the vent valve installed in the release path may become locked due to the pressure difference, which may hinder the release of the evaporated gas.

[0007] Furthermore, even if a variable valve capable of adjusting the opening in stages is installed along the release path, it is difficult to precisely control the opening with a variable valve. Therefore, it is not easy to quickly depressurize the fuel tank while preventing the vent valve from locking.

[0008] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a fuel tank treatment device that can quickly reduce the pressure in the fuel tank while preventing the valve from locking. [Means for solving the problem]

[0009] The fuel tank treatment device of the present invention comprises a first valve arranged inside a fuel tank in which fuel is stored, a release path that connects the first valve to the outside and through which gas released from the fuel tank flows, a second valve interposed in the release path, and an arithmetic control unit that adjusts the opening of the second valve, wherein the arithmetic control unit adjusts the opening of the second valve based on changes in the state of the fuel tank when the second valve is opened. [Effects of the Invention]

[0010] According to the fuel tank treatment device of the present invention, the opening degree of the second valve can be appropriately adjusted based on changes in the state of the fuel tank, thereby making it possible to keep the pressure loss in the release path at a predetermined level and preventing the first valve from locking. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a block diagram showing a connection configuration of a vehicle equipped with a fuel tank processing device according to an embodiment of the present invention. [Figure 2] 3 is a cross-sectional view showing a vent valve of the fuel tank treatment device according to the embodiment of the present invention. FIG. [Figure 3] 4 is a flowchart illustrating a method for depressurizing a fuel tank using a fuel tank treatment device according to an embodiment of the present invention. [Figure 4]1 is a block diagram showing a state in which a fuel tank is depressurized in a vehicle equipped with a fuel tank treatment device according to an embodiment of the present invention; [Figure 5] 10 is a correspondence table used to estimate pressure loss when depressurizing a fuel tank using a fuel tank processing device according to an embodiment of the present invention. [Figure 6] 10 is a correspondence table used to estimate the opening degree of an electromagnetic valve when depressurizing a fuel tank using a fuel tank processing device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] A fuel tank processing device 11 according to an embodiment of the present invention will be described in detail below with reference to the drawings. In the following description, the same components are generally designated by the same reference numerals, and repeated description will be omitted.

[0013] FIG. 1 is a block diagram showing the connection configuration of a vehicle 10 equipped with a fuel tank processing device 11.

[0014] Vehicle 10 is a means of transportation equipped with an engine. For example, vehicle 10 is an engine vehicle, an EV (Electric Vehicle), an HEV (Hybrid Electric Vehicle), a PHEV (Plug-in Hybrid Electric Vehicle), etc. Vehicle 10 may also be an EV equipped with an engine as a range extender.

[0015] The fuel tank treatment device 11 is a device for discharging gas 15 from the fuel tank 13 to the outside. Specifically, the fuel tank treatment device 11 mainly comprises the fuel tank 13, a first valve 14, a release path 16, a second valve 17, and an arithmetic control unit 18.

[0016] The fuel tank 13 is a device that stores fuel 12 to be supplied to an engine (not shown). The fuel 12 may be, for example, gasoline, diesel, or mixed oil.

[0017] Fuel filler opening 19 is provided at the top of fuel tank 13. Fuel filler opening 19 is a generally cylindrical device that is disposed to connect fuel tank 13 to the outside. Fuel filler opening 19 is the portion into which the nozzle of a fuel gun is inserted when fuel 12 is to be filled into fuel tank 13. The outer end of fuel filler opening 19 is sealed by lid 26.

[0018] The internal pressure sensor 21 is a device that measures the pressure inside the fuel tank 13. An electric signal indicating the internal pressure of the fuel tank 13 measured by the internal pressure sensor 21 is transmitted to the calculation control unit 18.

[0019] The arithmetic control unit 18 is made up of a CPU, RAM, ROM, a timer, etc., and executes predetermined arithmetic control processing based on input signals, etc., input from the internal pressure sensor 21, etc. For example, the arithmetic control unit 18 adjusts the opening degree of the second valve 17. Specifically, the arithmetic control unit 18 continuously adjusts the opening degree of the second valve 17 based on changes in the state of the fuel tank 13 when the second valve 17 is opened. The arithmetic control unit 18 also has a memory unit, and this memory unit stores a program for executing the processing of the fuel tank processing device 11, which will be described later.

[0020] The release path 16 is a conduit that connects the vent valve 141, which is the first valve 14, with the outside of the fuel tank 13 and is configured to allow the gas 15 released from the fuel tank 13 to flow through. The release path 16 is a pipe or the like made of synthetic resin, metal, or the like. The gas 15 is evaporated gas resulting from evaporation of the fuel 12, air present in the fuel tank 13, or a mixture of evaporated gas and air.

[0021] In the release path 16, from the upstream side in the flow of the gas 15, an FCV 28, a vent valve 141, an electromagnetic valve 171, a canister 20, an ELCM 23, a drain filter 22, and the like are installed.

[0022] The fuel path 27 is a pipe that branches off from the portion of the discharge path 16 where the canister 20 is disposed. The fuel path 27 is a pipe or the like made of synthetic resin, metal, or the like.

[0023] The FCV 28 is a valve for selectively cutting off the fuel supply, and is also called a fuel cut valve.

[0024] The vent valve 141 is an example of the first valve 14. The vent valve 141 is disposed inside the fuel tank 13 in which the fuel 12 is stored. The vent valve 141 is a valve that closes when the liquid level of the fuel 12 inside the fuel tank 13 reaches a certain level or higher, thereby preventing the fuel 12 from flowing out. A specific configuration of the vent valve 141 will be described later with reference to FIG. 2.

[0025] The electromagnetic valve 171 is an example of the second valve 17, and is disposed in the release path 16. The electromagnetic valve 171 is connected to an output terminal of the calculation control unit 18. The opening and closing operation and opening degree of the electromagnetic valve 171 are controlled by the calculation control unit 18. As will be described later, when refueling, the opening degree of the electromagnetic valve 171 is set to a degree that quickly releases pressure from the fuel tank 13 without locking the vent valve 141.

[0026] The canister 20 contains an adsorbent made of activated carbon or the like inside. The adsorbent allows the canister 20 to adsorb vaporized fuel contained in the gas 15 that is discharged from the fuel tank 13 and flows through the release path 16.

[0027] The ELCM 23 is also called a pressure-reducing leak check module. The ELCM 23 is a device that checks the fuel tank 13 and the canister 20 for leaks.

[0028] The drain filter 22 is a filter for purifying the gas 15 passing through the discharge path 16 .

[0029] The CPC 24 is also referred to as a purge control solenoid valve. The opening of the CPC 24 is set according to the duty ratio of a control signal output from the calculation control unit 18. When the ELCM 23 diagnoses a leak, the opening of the CPC 24 is adjusted according to the diagnosis situation. On the other hand, during normal control, the opening of the CPC 24 is controlled according to the operating state.

[0030] The intake manifold 25 is a device that distributes air to the intake ports of each cylinder of the engine (not shown here).

[0031] FIG. 2 is a cross-sectional view showing the vent valve 141 of the fuel tank treatment device 11. As shown in FIG.

[0032] The vent valve 141 mainly comprises a vent flange 29, a main body 30, a lid 31, a float 32, an elastic portion 33, and a communication pipe 34. The communication pipe 34 is connected to the release path 16 described above.

[0033] The vent flange 29 is disposed so as to close an opening formed in the upper surface of the fuel tank 13. The main body 30 is disposed on the lower surface of the vent flange 29. The lid 31 closes the lower end of the vent flange 29. The float 32 is disposed inside the main body 30 so as to be able to move up and down, and is made of a material with a lower specific gravity than the fuel 12 described above, such as foamed synthetic resin. The elastic portion 33 is disposed on the upper surface of the lid 31, and is made of an elastic material that urges the float 32 upward. The lid 31 is formed with a communication port 35 that connects the inside of the main body 30 with the inside of the fuel tank 13.

[0034] When the liquid level of the fuel 12 in the fuel tank 13 rises, the fuel 12 flows into the main body 30 through the communication port 35, causing the float 32 to rise. Then, the upper end of the float 32 blocks the lower end of the communication pipe 34, blocking the outflow of the fuel 12 to the outside.

[0035] As described above, the vent valve 141 has the float 32 that is movable in the vertical direction. Therefore, depending on the pressure loss in the discharge path 16 connected to the communicating pipe 34, there is a risk that the float 32 may inadvertently block the lower end of the communicating pipe 34. In this embodiment, to prevent such a phenomenon, the opening degree of the electromagnetic valve 171 interposed in the discharge path 16 is controlled, as will be described later.

[0036] Fig. 3 is a flowchart showing a method for depressurizing the fuel tank 13 by the fuel tank processing device 11. The method for depressurizing the fuel tank 13 will be described based on the flowchart of Fig. 3 and with reference to the above-mentioned figures.

[0037] In step S10, the calculation control unit 18 determines whether or not there is a refueling request. Here, a refueling request is, for example, an operation of a fuel filler lever, button, etc. (not shown) by an occupant of the vehicle 10 to fill the fuel tank 13 with fuel 12.

[0038] If the answer to step S10 is YES, that is, if there is a refueling request, the calculation control unit 18 proceeds to step S11.

[0039] If the answer is NO in step S10, that is, if there is no refueling request, the calculation control unit 18 proceeds to END.

[0040] In step S11, the calculation control unit 18 acquires the internal pressure of the fuel tank 13. Specifically, the calculation control unit 18 measures the internal pressure of the fuel tank 13 using the internal pressure sensor 21.

[0041] In step S12, the calculation control unit 18 measures the amount of fuel 12 present inside the fuel tank 13 using a fuel level sensor (not shown).

[0042] In step S13, the calculation control unit 18 determines the amount of air in the fuel tank 13. That is, the amount of air present in the fuel tank 13 is calculated by subtracting the volume of the fuel 12 present in the fuel tank 13 from the total volume of the fuel tank 13.

[0043] In step S14, the arithmetic and control unit 18 opens the electromagnetic valve 171 by a predetermined opening amount. Specifically, the arithmetic and control unit 18 sets the opening amount of the electromagnetic valve 171 to, for example, 50%.

[0044] 4 is a block diagram showing the situation in which the pressure in the fuel tank 13 is reduced in step S14. In FIG. 4, the path through which the gas 15 inside the fuel tank 13 is discharged is indicated by a dotted arrow. When the electromagnetic valve 171 is opened, the gas 15 present inside the fuel tank 13 is discharged to the outside of the fuel tank 13 via the discharge path 16. Specifically, the gas 15 passes through the inside of the fuel tank 13 and the electromagnetic valve 171, the canister 20, the ELCM 23, and the drain filter 22 that are arranged in the discharge path 16, before being discharged to the outside, for example, outside the vehicle.

[0045] In step S15, the calculation control unit 18 calculates the pressure loss in the release path 16 when the electromagnetic valve 171 is opened by a predetermined opening degree. Furthermore, in step S15, an appropriate opening degree of the electromagnetic valve 171 is estimated.

[0046] The operation of the calculation control unit 18 in step S15 will be described with reference to Figures 5 and 6. First, using the correspondence table shown in Figure 5, the pressure loss in the release path 16 is estimated from the amount of fuel 12 inside the fuel tank 13, the time required for depressurization, and the change in the internal pressure of the fuel tank 13. Next, using the correspondence table shown in Figure 6, the appropriate opening degree of the electromagnetic valve 171 is estimated from the amount of fuel 12 inside the fuel tank 13, the pressure loss in the release path 16, and the change in the internal pressure of the fuel tank 13. These correspondence tables are prepared in a state of being stored in advance in a storage unit, such as a semiconductor storage device, provided inside or outside the calculation control unit 18 described above.

[0047] The table shown in Fig. 5 is a correspondence table used to estimate pressure loss when depressurizing the fuel tank 13 using the fuel tank processing device 11. Such a correspondence table is also called a look-up table in which output values ​​are pre-assigned according to input information. The input values ​​in the correspondence table shown in Fig. 5 are the time required for depressurization and the change in internal pressure of the fuel tank 13. The time required for depressurization is, for example, the time required for the internal pressure of the fuel tank 13 to change from 2.0 kPa to 0 kPa. Furthermore, the time required for depressurization represents the degree of decrease in the internal pressure of the fuel tank 13.

[0048] The output value here is the pressure loss in the discharge path 16, and is also called drain pressure loss. In this embodiment, a plurality of correspondence tables are prepared according to the amount of fuel 12 inside the fuel tank 13. For example, correspondence tables are prepared for the amount of fuel 12 in 1-liter increments from 1 liter to 70 liters.

[0049] Here, the interrelationships among the time required for depressurization, the change in the internal pressure of the fuel tank 13, the amount of fuel 12 inside the fuel tank 13, and the pressure loss in the release path 16 are very complex. Furthermore, these interrelationships cannot be uniquely determined due to factors such as the degree of clogging of the drain filter 22, the adsorption state of the canister 20, and deformation of the piping that constitutes the release path 16. In this embodiment, in consideration of these complex interrelationships, a correspondence table is prepared in advance, making it possible to easily and quickly estimate the pressure loss in the release path 16. The same applies to the correspondence table shown in FIG. 6.

[0050] For example, if the amount of fuel 12 inside the fuel tank 13 is 1 liter, the time required for depressurization is 3 seconds, and the internal pressure of the fuel tank 13 changes from 6.0 kPa to 4.0 kPa, the pressure loss in the release path 16 is estimated to be 2.5 kPa.

[0051] Fig. 6 is a correspondence table used to estimate the opening degree of the electromagnetic valve 171 when depressurizing the fuel tank 13 using the fuel tank processing device 11. The input values ​​in the correspondence table shown in Fig. 6 are the pressure loss in the release path 16 and the change in the internal pressure of the fuel tank 13. The output value here is the desired opening degree of the electromagnetic valve 171. Here, multiple correspondence tables are prepared according to the amount of fuel 12 inside the fuel tank 13. For example, correspondence tables are prepared in 1 liter increments for amounts of fuel 12 ranging from 1 liter to 70 liters.

[0052] For example, if the amount of fuel 12 inside the fuel tank 13 is 1 liter, the pressure loss in the release path 16 is 1.0 kPa, and the internal pressure of the fuel tank 13 changes from 6.0 kPa to 4.0 kPa, it is estimated that the desired opening degree of the solenoid valve 171 is 5.0%.

[0053] In step S16, the calculation control unit 18 corrects the opening degree of the electromagnetic valve 171. Specifically, the calculation control unit 18 corrects the opening degree of the electromagnetic valve 171 to the opening degree estimated in step S15. In this way, the opening degree of the second valve 17 can be appropriately adjusted, the pressure loss in the release path 16 can be set to a predetermined level, and the vent valve 141 can be prevented from locking. Furthermore, the internal pressure of the fuel tank 13 can be quickly reduced to, for example, atmospheric pressure.

[0054] In step S17, the calculation control unit 18 determines whether or not the pressure in the fuel tank 13 has been reduced. Specifically, the calculation control unit 18 determines whether or not the internal pressure of the fuel tank 13 measured by the internal pressure sensor 21 has been reduced to approximately the same as atmospheric pressure.

[0055] If the answer is YES in step S17, that is, if the depressurization of the fuel tank 13 is complete, the calculation and control unit 18 causes the fuel tank processing device 11 to complete the depressurization of the fuel tank 13. This allows the occupant or worker to open the lid 26. Because the internal pressure of the fuel tank 13 has been sufficiently reduced by the operations up to step S17, the fuel 12 and gas 15 will not be ejected to the outside from the lid 26. Thereafter, the nozzle of the fuel gun is inserted into the fuel filler opening 19, and the fuel 12 is filled into the fuel tank 13.

[0056] If the answer is NO in step S17, that is, if the depressurization of the fuel tank 13 has not been completed, the calculation control unit 18 proceeds to step S15 and continues depressurizing the fuel tank 13.

[0057] The above is the explanation of the decompression of the fuel tank 13 using the fuel tank treatment device 11.

[0058] The technical ideas that can be understood from the above-described embodiment will be described below together with their effects.

[0059] The fuel tank treatment device of the present invention includes a first valve disposed inside a fuel tank that stores fuel, a release path that connects the first valve to the outside and through which gas released from the fuel tank flows, a second valve disposed in the release path, and an arithmetic and control unit that adjusts the aperture of the second valve, wherein the arithmetic and control unit adjusts the aperture of the second valve based on a change in the state of the fuel tank when the second valve is opened. According to the fuel tank treatment device of the present invention, by appropriately adjusting the aperture of the second valve, the pressure loss in the release path can be set to a predetermined level, and locking of the first valve can be suppressed.

[0060] In addition, in the fuel tank treatment device of the present invention, the first valve is a vent valve, and the fuel tank treatment device of the present invention can prevent the vent valve from locking when gas inside the fuel tank is released to the outside via the release path.

[0061] In addition, in the fuel tank processing device of the present invention, the calculation control unit adjusts the opening degree of the second valve based on the amount of fuel present in the fuel tank and the degree of decrease in the internal pressure of the fuel tank when the second valve is in the open state. According to the fuel tank processing device of the present invention, the opening degree of the second valve can be appropriately adjusted depending on the conditions of the fuel tank and the release path.

[0062] In addition, in the fuel tank processing device of the present invention, when a refueling operation is performed, the calculation control unit acquires information indicating the internal pressure of the fuel tank and the amount of fuel present in the fuel tank, calculates the degree of decrease in the internal pressure of the fuel tank with the aperture of the second valve set to a predetermined amount, and adjusts the aperture of the second valve based on the internal pressure of the fuel tank, the amount of fuel present in the fuel tank, and the degree of decrease in the internal pressure of the fuel tank. According to the fuel tank processing device of the present invention, by opening the second valve once and then adjusting the aperture of the second valve according to the degree of decrease in the internal pressure of the fuel tank, etc., it is possible to maintain the pressure loss in the release path at a predetermined level even if the amount of fuel present in the fuel tank, the condition of the release path, etc., changes, and it is possible to prevent the first valve from locking.

[0063] In addition, in the fuel tank treatment device of the present invention, the second valve is an electromagnetic valve. By using an electromagnetic valve as the second valve, the opening degree of the electromagnetic valve can be adjusted continuously, allowing for precise control of pressure loss in the release path.

[0064] Although the embodiments of the present invention have been described above, the present invention is not limited to these and can be modified within the scope of the present invention. In addition, the above-described embodiments can be combined with each other. [Explanation of symbols]

[0065] 10 vehicles 11 Fuel tank treatment equipment 12 Fuel 13. Fuel tank 14 First valve 141 Vent valve 15 Gases 16 Release Pathway 17 Second valve 171 Solenoid valve 18 Calculation control unit 19 Fuel filler 20 canisters 21 Internal pressure sensor 22 Drain filter 23 ELCM 24 CPC 25 intake manifold 26 Lid 27 Fuel line 28 FCV 29 Vent flange 30 Main body 31 Lid 32 Float 33 Elastic part 34 Communication pipe 35 Connecting port

Claims

1. a first valve disposed inside a fuel tank in which fuel is stored; a release path that connects the first valve to the outside and through which gas released from the fuel tank flows; a second valve interposed in the discharge path; a calculation control unit that adjusts the opening degree of the second valve, The arithmetic and control unit 10. A fuel tank processing device comprising: a fuel tank control unit that adjusts the opening of the second valve based on a change in the state of the fuel tank when the second valve is opened.

2. 2. The fuel tank treatment device according to claim 1, wherein the first valve is a vent valve.

3. 2. The fuel tank treatment device according to claim 1, wherein the calculation control unit adjusts the opening degree of the second valve based on the amount of fuel present inside the fuel tank and the degree of decrease in internal pressure of the fuel tank when the second valve is in the open state.

4. The arithmetic and control unit Once the refueling operation is performed, obtaining information indicating an internal pressure of the fuel tank and an amount of the fuel present in the fuel tank; Calculating a degree of decrease in the internal pressure of the fuel tank while the second valve is opened to a predetermined amount; 2. The fuel tank treatment device according to claim 1, wherein the opening degree of the second valve is adjusted based on the internal pressure of the fuel tank, the amount of the fuel present in the fuel tank, and the degree of decrease in the internal pressure of the fuel tank.

5. 2. The fuel tank treatment device according to claim 1, wherein the second valve is an electromagnetic valve.

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