JP2011180093A - Fuel remaining quantity detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact sized fuel remaining quantity detector with general versatility and high detection precision. <P>SOLUTION: A detecting control unit 40 introduces air from outside of a housing 11 to a communicating chamber 13 after decompressing the communicating chamber 13 by a movable member 16 under the condition where aperture between the communicating chamber 13 and a tank chamber 3 in the housing 11 is blocked with a first valve 30 and aperture between the communicating chamber 13 and the outside of housing 11 is opened up with a second valve 32. Then, under the condition where aperture between the communicating chamber 13 and a tank chamber 3 is opened up with the first valve 30 and aperture between the communicating chamber 13 and the outside of housing 11 is blocked with the second valve 32, pressure of the tank chamber 3 is measured after the communicating chamber 13 is pressurized with the movable member 16. Finally, decompression treatment and pressurization treatment are repeated until the pressure value measured reaches a predetermined threshold value Pth or above, and when the pressure value measured reaches the threshold value Pth or above, the fuel remaining quantity Vf is computed based on the pressure value reaching the threshold value Pth concerned or above. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a fuel remaining amount detection device that detects a remaining fuel amount in a fuel tank.

  Conventionally, in a housing that forms a communication chamber that communicates with a tank chamber in a fuel tank, the communication chamber is driven to increase or decrease pressure by driving a movable member, and a fuel that detects the remaining amount of fuel according to the pressure in the tank chamber A remaining amount detection device is known. According to such a fuel remaining amount detection device, the remaining amount of fuel can be detected without changing the size of the device elements based on the pressure in the tank chamber that changes depending on the specifications of the fuel tank, so that versatility is improved. Will be.

  For example, in the fuel remaining amount detection device disclosed in Patent Document 1 as the prior art, the pressure change width of the tank chamber is measured every time the piston, which is a movable member, is reciprocated a plurality of times, and the average value of the pressure change widths of each time is obtained. Based on this, the remaining fuel amount is calculated.

Japanese Patent Laid-Open No. 2-19717

  However, in the case of the prior art disclosed in Patent Document 1 described above, in order to accurately detect the remaining fuel amount, it is necessary to increase the measurement accuracy of the pressure change range. The volume change amount of the communication chamber for generating a pressure change by the reciprocating drive must be increased. Here, in order to increase the volume change amount of the communication chamber, the diameter of the piston and the driving amount are inevitably increased, leading to an increase in the device size.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a small fuel remaining amount detection device with high versatility and high detection accuracy.

  According to a first aspect of the present invention, there is provided a housing that internally forms a communication chamber that communicates with a tank chamber in a fuel tank, a movable member that is driven in the housing to pressurize and depressurize the communication chamber, a communication chamber, and a tank The first on-off valve that opens and closes between the chambers, the second on-off valve that opens and closes between the communication chamber and the outside of the housing, the movable member, and the first and second on-off valves are controlled to detect the remaining amount of fuel in the tank chamber A detection control unit that closes the communication chamber and the tank chamber by the first on-off valve and opens the communication chamber and the outside of the housing by the second on-off valve. Pressure reducing means for reducing the pressure by a movable member and introducing air from the outside of the housing to the communication chamber, and the first on-off valve opens the space between the communication chamber and the tank chamber, and the second on-off valve opens the communication chamber and the outside of the housing. In the closed state, the communication chamber after the decompression process by the decompression process unit is pressurized by the movable member to measure the pressure value of the tank chamber, and the pressure value measured by the pressurization process unit is a predetermined value. When the pressure value measured by the pressure treatment means repeats the pressure reduction treatment by the pressure reduction treatment means and the pressure treatment by the pressure treatment means until the pressure value is greater than or equal to the threshold value, And a remaining amount calculating means for calculating the remaining amount of fuel based on the pressure value described above.

  As described above, according to the first aspect of the present invention, the communication chamber formed in the housing is pressurized by the movable member driven in the housing, and the pressure value of the tank chamber in the fuel tank communicating with the communication chamber is determined. And the remaining amount of fuel is detected (calculated) based on the measurement result. According to this, since the remaining amount of fuel can be detected without changing the size of the device element based on the pressure value of the tank chamber that changes depending on the specifications of the fuel tank, versatility can be improved.

  Further, according to the first aspect of the present invention, in a state where the communication between the communication chamber and the tank chamber is closed by the first on-off valve and the space between the communication chamber and the outside of the housing is opened by the second on-off valve, the movable member The communication chamber is decompressed and air is introduced from the outside of the housing into the communication chamber. During the decompression process, the communication chamber opened to the outside of the housing is closed with respect to the tank chamber, so that the pressure in the tank chamber is maintained. Thereafter, when the first opening / closing valve opens the communication chamber and the tank chamber and the second opening / closing valve closes the communication chamber and the outside of the housing, the communication chamber introduced with air is pressurized by the movable member. Then, the pressure value in the tank chamber is measured. During the pressurizing process, the communication chamber closed to the outside of the housing is opened to the tank chamber, so that the tank chamber is pressurized together with the communication chamber.

  According to the first aspect of the present invention, the pressure reduction process and the pressurization process described above are repeated. Therefore, the pressure value equal to or higher than the threshold value measured in the final pressurization process is determined by a plurality of pressure reduction processes. It will increase depending on the amount of air introduced. That is, even if the pressure change that occurs when the movable member is driven by a single decompression process and pressurization process is small, the pressure change that occurs when the movable member is repeatedly driven by a plurality of these processes increases. Measurement accuracy of the pressure value can be increased regardless of the size and driving amount. Therefore, based on the pressure value equal to or higher than the threshold value, the remaining amount of fuel can be accurately calculated even with a small device size.

  In addition, according to the first aspect of the present invention, even if a fixed threshold value that does not depend on the specifications of the fuel tank is adopted, the decompression process and the pressurization process are repeated a number of times according to the specifications, so that the remaining fuel amount It is possible to reliably measure the pressure value at the level necessary for the calculation of Therefore, it is not necessary to change the configuration of the detection control unit that calculates the fuel remaining amount by repeating the decompression process and the pressurization process in accordance with the specifications of the fuel tank. It is.

  According to the second aspect of the present invention, the space in which the sum of the volume of the hollow portion in the tank chamber and the volume of the communication portion that is in communication with the tank chamber and includes the communication chamber varies depending on the remaining amount of fuel. When the sum of the spatial volume and the remaining amount of fuel at a pressure value equal to or greater than a threshold is defined as a predetermined overall volume, the remaining amount calculating means correlates with the pressure value equal to or greater than the threshold. Is subtracted from the total volume to calculate the remaining fuel amount.

  As described above, according to the second aspect of the present invention, the sum of the volume of the hollow portion in the tank chamber and the volume of the communication portion that communicates with the tank chamber and includes the communication chamber is determined according to the remaining fuel amount. The changing space volume correlates with the pressure value of the tank chamber. On the other hand, the total volume, which is the sum of the space volume and the remaining fuel amount when measuring a pressure value equal to or greater than the threshold value, is a predetermined volume. Therefore, by subtracting the spatial volume correlated with the pressure value above the measured threshold value from the total volume, the remaining amount of fuel can be accurately calculated based on the pressure value.

  According to the third aspect of the present invention, the first on-off valve receives the pressure of the communication chamber depressurized by the movable member and closes the space between the communication chamber and the tank chamber, while the communication chamber is pressurized by the movable member. This is a check valve that opens between the communication chamber and the tank chamber under the pressure of. According to such a check valve, when the communication chamber is decompressed by the movable member in the decompression process, the communication chamber and the tank chamber can be mechanically and automatically closed by receiving the pressure of the communication chamber. On the other hand, according to the check valve, when the communication chamber is pressurized by the movable member in the pressurizing process, the communication chamber and the tank chamber are mechanically and automatically opened by receiving the pressure of the communication chamber. obtain. According to these, it is possible to simplify the configuration of the second on-off valve and contribute to the downsizing of the apparatus size.

It is a schematic block diagram which shows the fuel residual amount detection apparatus by one Embodiment of this invention. It is a schematic diagram for demonstrating the detection principle of the fuel residual amount by the fuel residual amount detection apparatus by one Embodiment of this invention. It is a schematic diagram for demonstrating the detection principle of the fuel residual amount by the fuel residual amount detection apparatus by one Embodiment of this invention. It is a schematic diagram for demonstrating the detection principle of the fuel residual amount by the fuel residual amount detection apparatus by one Embodiment of this invention. It is a flowchart for demonstrating the detection control flow which the detection control unit 40 of the fuel residual amount detection apparatus by one Embodiment of this invention implements.

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

(Constitution)
FIG. 1 shows a schematic configuration of a remaining fuel amount detection device 1 according to an embodiment of the present invention. The fuel remaining amount detection device 1 is mounted on a fuel tank 2 that stores fuel 4 supplied to an internal combustion engine of a vehicle, and detects a fuel remaining amount Vf in the tank 2. The fuel remaining amount detection device 1 includes an accumulator 10, pipes 20 and 22, on-off valves 30 and 32, and a detection control unit 40.

  The accumulator 10 has a housing 11 and a movable member 16. The cylindrical cylinder-shaped housing 11 is fixed to the fuel tank 2 via the first pipe 20, and forms a communication chamber 13 as a cylinder chamber partitioned with respect to the external space 12. The columnar piston-like movable member 16 is inserted into the housing 11 so as to be coaxial and slidable in the axial direction. The movable member 16 pressurizes and depressurizes the communication chamber 13 by reciprocal movement in the axial direction. Here, the left direction in FIG. 2 is the pressurizing direction Dp of the communication chamber 13 by the movable member 16, and the right direction in FIG. 2 is the pressure reducing direction Dr of the communication chamber 13 by the movable member 16.

  The accumulator 10 further has a drive source 15. The drive source 15 of the present embodiment includes a drive motor 17, a pinion 18, a rack 19 and the like. The drive motor 17 is an electric motor that is electrically connected to a control circuit 44 (described later in detail) of the detection control unit 40, and rotationally drives the output shaft according to the control of the circuit 44. The pinion 18 is connected to the output shaft of the drive motor 17 and rotates together with the output shaft. The rack 19 meshes with the pinion 18 and moves linearly according to the rotation of the pinion 18. The rack 19 is connected to the movable member 16 and reciprocates integrally with the movable member 16. According to the drive source 15 having such a configuration, when the drive motor 17 is controlled by the detection control unit 40 and the output shaft is rotationally driven, the rotational movement of the output shaft is caused to reciprocate by the movable member 16 by the action of the pinion 18 and the rack 19. It will be converted to linear motion. Therefore, hereinafter, controlling the drive motor 17 will be described as controlling the movable member 16.

  In the first pipe 20 having a smaller diameter than the housing 11, one end is coupled to the fuel tank 2, and the other end is coupled to the housing 11. A first passage 21 formed inside the first pipe 20 connects between the tank chamber 3 in the fuel tank 2 and the communication chamber 13 in the housing 11. A first opening / closing valve 30 is installed at an intermediate portion of the first pipe 20. The first opening / closing valve 30 is configured by electromagnetically actuating a mechanically operated check valve, and opens / closes according to a differential pressure between the tank chamber 3 and the communication chamber 13. The first opening / closing valve 30 opens the first passage 21 by an opening operation or an opening operation by energization in response to the communication chamber 13 having a higher pressure than the tank chamber 3 in a non-energized state, and communicates with the tank chamber 3. Communication with 13 is allowed. On the other hand, the first on-off valve 30 closes the first passage 21 by a closing operation in response to the communication chamber 13 having a lower pressure than the tank chamber 3 in a non-energized state, and the tank chamber 3 and the communication chamber 13 Block communication. Here, since the pressure difference between the chambers 3 and 13 changes as the communication chamber 13 is pressurized and depressurized by the reciprocating movement of the movable member 16, the first on-off valve 30 will be described below by switching the energized state. The opening / closing of the first opening / closing valve 30 by controlling the movable member 16 as well as opening / closing the opening / closing is described as controlling the first opening / closing valve 30.

  In the second pipe 22 having a smaller diameter than the housing 11, one end is coupled to the housing 11, and the other end is open to the atmosphere in the external space 12 of the housing 11. A second passage 23 formed inside the second pipe 22 connects between the communication chamber 13 in the housing 11 and the space 12 outside the housing 11. A second on-off valve 32 is installed at the end of the second pipe 22 on the atmosphere opening side. The second on-off valve 32 is an electromagnetically operated on / off valve that is electrically connected to the control circuit 44 of the detection control unit 40, and opens and closes according to the control of the circuit 44. The second on-off valve 32 opens the second passage 23 by opening operation, and allows communication between the communication chamber 13 and the external space 12. On the other hand, the second opening / closing valve 32 closes the second passage 23 by a closing operation, and blocks communication between the communication chamber 13 and the external space 12.

  The detection control unit 40 includes a pressure sensor 42 and a control circuit 44. The pressure sensor 42 is an electronic sensor that is installed on the ceiling surface of the fuel tank 2 exposed in the tank chamber 3 and is electrically connected to the control circuit 44, and measures the pressure value in the tank chamber 3. To the circuit 44. The control circuit 44 is mainly composed of a microcomputer having a memory 45. The control circuit 44 detects the fuel remaining amount Vf of the tank chamber 3 based on the pressure value of the tank chamber 3 measured by the pressure sensor 42 while controlling the movable member 16 and the on-off valves 30 and 32.

(Detection principle)
Below, the detection principle of the fuel remaining amount Vf by the fuel remaining amount detection apparatus 1 demonstrated above is demonstrated, referring FIGS. Here, as shown in FIGS. 2 to 4, in this embodiment, the volume V <b> 1 of the hollow portion (portion excluding the fuel 4) 3 a of the tank chamber 3 in the fuel tank 2 and the communication portion between the tank chamber 3 are used. The sum of the communication chamber 13 and the total volume V2 of the passages 21 and 23 is defined as a space volume Vs. Furthermore, in the present embodiment, the sum of the space volume Vs and the remaining fuel amount Vf is defined as the total volume Vt. The total volume V2 of the communication chamber 13 and the passages 21 and 23 is shown as a large volume in FIGS. 2 to 4, but this is for easy understanding of the description. It is set sufficiently smaller than the volume V1 of the hollow portion 3a when the remaining amount Vf reaches the upper limit value.

  FIG. 2 shows a state in which the space volume Vs becomes the space volume Vs0 corresponding to the fuel remaining amount Vf because the movable member 16 is positioned at a reference position where the total volume Vt is a predetermined volume Vt0. . In this embodiment, the decompression process is executed from this state. Specifically, as shown in FIG. 3, the second passage 23 is opened by the second on-off valve 32, and the movable member 16 is moved from the reference position in the pressure reducing direction Dr by the set distance X, thereby allowing the communication chamber 13 to be opened. Reduce pressure. At this time, a differential pressure is generated between the communication chamber 13 to be decompressed, the tank chamber 3 and the external space 12. As a result, the first passage 21 is closed by the non-energized first on-off valve 30 so that the pressure in the tank chamber 3 is maintained at substantially the same pressure as before the start of the decompression process, and the second passage from the external space 12. Air is introduced into the communication chamber 13 through 23.

When the movable member 16 has reached the decompression end position at the distance X from the reference position in this way, when the first on-off valve 30 in the non-energized state opens the first passage 21 by the start of pressurization processing described later, the communication is established. The pressure in the chamber 13 and the passages 21 and 23 substantially matches the pressure in the tank chamber 3. This is because the total volume V2 of the communication chamber 13 and the passages 21, 23 is sufficiently smaller than the volume V1 of the tank chamber 3. Here, as shown in FIG. 3, the volume change amount of the communication chamber 13 due to the movement of the movable member 16 from the reference position to the decompression end position, that is, the change amount of the space volume Vs is ΔVx, and immediately after the first passage 21 is opened. Assuming that the pressure of each of the portions 3, 13, 21, 23 in P is P0, the following equation (1) is established according to Boyle's law. In the present embodiment, the remaining fuel amount Vf is detected within a time period in which the temperature change can be substantially ignored. Therefore, the pressure P0 is the pressure in the tank chamber 3 before the pressurizing process is started (see FIG. 2). ) And the proportionality coefficient in Boyle's law is substantially a constant value k. Further, the change amount ΔVx of the space volume Vs is a physical quantity determined by a predetermined set distance X.
Vs = Vs0 + ΔVx = k / P0 (1)

  Subsequently, in the present embodiment, a pressurizing process is executed. Specifically, as shown in FIG. 4, the second passage 23 is closed by the second opening / closing valve 32, and the movable member 16 is moved from the decompression end position to the pressurizing direction Dp by the set distance X, thereby enabling the external space. The communication chamber 13 sealed against the pressure 12 is pressurized. At this time, a differential pressure is generated between the communication chamber 13 and the tank chamber 3, and as a result, the first passage 21 is opened by the non-energized first on-off valve 30, and the communication chamber 13 is pressurized more than the pressure P0. Will be.

Thus, when the movable member 16 is returned to the reference position in FIG. 4, the pressures in the communication chamber 13 and the passages 21 and 23 substantially match the pressure in the tank chamber 3. That is, the tank chamber 3 as well as the communication chamber 13 is in a pressurized state. Here, as shown in FIG. 4, when ΔPx is an increase change amount of the pressure of each of the portions 3, 13, 21, and 23 due to the movement of the movable member 16 from the decompression end position to the reference position, according to Boyle's law, Formula (2) is materialized.
Vs = Vs0 = k / (P0 + ΔPx) (2)

Thereafter, in this embodiment, the combination of the decompression process and the pressurization process is repeated. However, the pressure of each of the portions 3, 13, 21, 23 immediately after opening the first passage 21 after executing the second decompression process has returned the movable member 16 to the reference position by the first pressurization process. Is substantially equal to the pressure (P0 + ΔPx) at that time, the following equation (3) is established. Further, the pressure of each of the portions 3, 13, 21, 23 when the movable member 16 returns to the reference position by the second pressurizing process is immediately after the first passage 21 is opened by the second pressurizing process. Since this is substantially the same as that increased by ΔPx from the pressure at, the following equation (4) is established.
Vs = Vs0 + ΔVx = k / (P0 + ΔPx) (3)
Vs = Vs0 = k / (P0 + 2 · ΔPx) (4)

From the above, the following formula (5) is established by repeating the combination of the decompression process and the pressurization process a plurality of times. In the equation (5), ΣΔPx represents a value obtained by adding the pressure change amount ΔPx due to the pressurization process by the number of execution times of the combination of the decompression process and the pressurization process.
Vs = Vs0 = k / (P0 + ΣΔPx) (5)

Here, as shown in FIGS. 2 and 4, there is a correlation represented by the following equation (6) between the total volume Vt0 and the space volume Vs0 at the reference position and the remaining fuel amount Vf. Therefore, by combining the above equations (1) and (5) together with this equation (6), the following equation (7) is obtained.
Vf = Vt0−Vs0 (6)
Vf = Vt0−ΔVx · P0 / ΣΔPx = Vt0−ΔVx · P0 / {(P0 + ΣΔPx) −P0} (7)

  Therefore, in the present embodiment, the pressure value P0 of the tank chamber 3 is measured as an initial value by the pressure sensor 42 before the start of the first pressurizing process, and the pressure value of the tank chamber 3 at the end of each pressurizing process. The sensor 42 measures (P0 + ΣΔPx). Further, in the present embodiment, the measurement accuracy of the pressure value is increased by repeating the combination of the depressurization process and the pressurization process until the pressure value (P0 + ΣΔPx) of the tank chamber 3 becomes equal to or greater than the predetermined threshold value Pth, The fuel remaining amount Vf according to (7) can be accurately calculated.

(Detection control flow)
Below, the detection control flow which the detection control unit 40 implements based on the detection principle demonstrated above is demonstrated, referring FIG. The detection control flow starts when the control circuit 44 executes a computer program stored in the memory 45, and starts when the engine switch of the vehicle is turned on, and ends when the switch is turned off.

  In S100 of the detection control flow, the movable member 16 is positioned at the reference position in the housing 11, and the first passage 21 is closed by the non-energized first opening / closing valve 30, and the second passage 23 is closed by the second opening / closing valve 32. Is released. Next, in S <b> 101, the pressure value P <b> 0 of the tank chamber 3 that is an initial value is measured by the pressure sensor 42 and stored in the memory 45.

  Subsequently, in S102, the movable member 16 is driven from the reference position to the decompression end position, the first passage 21 is closed by the non-energized first opening / closing valve 30, and the second passage 23 is opened by the second opening / closing valve 32. To do. As a result, the communication chamber 13 is decompressed, and air is introduced from the external space 12 of the housing 11 into the communication chamber 13.

  In S103, the movable member 16 is driven from the decompression end position to the reference position, the first passage 21 is opened by the non-energized first opening / closing valve 30, and the second passage 23 is opened by the second opening / closing valve 32. Block. As a result, the communication chamber 13 is sealed against the external space 12 and pressurized together with the tank chamber 3.

  Subsequently, in S104, the first passage 21 is closed by the non-energized first opening / closing valve 30 with the stop of the movable member 16, and the pressure in the communication chamber 13 is substantially the same across the passage 21. The pressure value (P0 + ΣΔPx) of the tank chamber 3 is measured by the pressure sensor 42 and stored in the memory 45. In S105, the pressure value (P0 + ΣΔPx) measured in S104 is read from the memory 45, and it is determined whether or not the pressure value is equal to or higher than a threshold value Pth (for example, 50 kPa).

  If a negative determination is made in S105, the process returns to S102, and S102 and subsequent S103 to S105 are repeated. On the other hand, when a positive determination is made in S105, the process proceeds to S106. In S106, the pressure values P0 and (P0 + ΣΔPx) measured in S101 and immediately preceding S104 are read, and the fuel remaining amount is determined according to the above equation (7) representing the correlation between these pressure values and the preset values Vt0 and ΔVx. Vf is calculated.

  In S107 after the fuel remaining amount Vf is calculated in this way, the first passage 21 is forced by the energized first opening / closing valve 32 until the pressure value measured by the pressure sensor 42 falls below a set value Pset (for example, 5 kPa). The second passage 23 is opened by the second opening / closing valve 32, and the process returns to S101.

  As described above, in the fuel remaining amount detection device 1 of the present embodiment, the communication chamber 13 formed in the housing 11 is pressurized by the movable member 16 and the pressure of the tank chamber 3 in the fuel tank 2 communicating with the communication chamber 13 is increased. The value is measured, and the remaining fuel amount Vf is detected (calculated) based on the measurement result. According to this, based on the pressure value of the tank chamber 3 that varies depending on the specifications of the fuel tank 2, the remaining fuel level Vf can be detected without changing the size of all the device elements, so that versatility is improved. become.

  Further, in the remaining fuel amount detection device 1, the pressure value measured in the final pressurization process is repeated by repeating the decompression process in S102 of the detection control flow and the pressurization process in S103 and S104 of the same flow. P0 + ΣΔPx) is equal to or greater than a predetermined threshold value Pth. That is, even if the pressure change caused by the reciprocating movement of the movable member 16 by a single decompression process and the pressurizing process is small, the pressure change caused by the reciprocating movement of the movable member 16 by a plurality of times of these processes becomes large. Therefore, it is possible to increase the measurement accuracy of the pressure value without increasing the diameter dimension and the movement amount of the movable member 16, and therefore the fuel remaining amount Vf is accurately calculated even with a small device size. It can be done.

  Moreover, in the fuel remaining amount detection device 1, even if a fixed threshold value Pth that does not depend on the specification of the fuel tank 2 is adopted, the decompression process and the pressurization process are repeated as many times as the specification, so that the fuel remaining amount is determined. The pressure value (P0 + ΣΔPx) at a level necessary for calculating Vf is reliably measured. Therefore, the configuration of the detection control unit 40 (for example, the storage contents of the memory 45 for executing the detection control flow) for calculating the fuel remaining amount Vf by repeating the pressure reduction process and the pressure increase process depends on the specifications of the fuel tank 2. This also increases general versatility.

  In the embodiment described above, the detection control unit 40 that executes S102 corresponds to “decompression processing means”, and the detection control unit 40 that executes S103 and S104 corresponds to “pressurization processing means”. The detection control unit 40 that executes S105 corresponds to “repetition processing means”, and the detection control unit 40 that executes S101 and S106 corresponds to “remaining amount calculation means”.

(Other embodiments)
Although one embodiment of the present invention has been described so far, the present invention is not construed as being limited to the embodiment, and can be applied to various embodiments without departing from the gist of the present invention. is there.

  Specifically, the first on-off valve 30 may be configured by an electromagnetically operated on / off valve or the like according to the second on-off valve 32 and may be directly controllable by the control circuit 44. In this case, the first passage 21 is opened by the first opening / closing valve 30 in S100 and S104 of the detection control flow, and the pressure value in the tank chamber 3 is indirectly set by the pressure sensor 42 provided in the communication chamber 13. You may measure. Furthermore, the drive source 15 for driving the piston-like movable member 16 in the accumulator 10 may be, for example, one using a crank mechanism as long as the movable member 16 can be driven to reciprocate. In addition, as an accumulator, in addition to the one that realizes pressure increase / decrease of the communication chamber 13 by reciprocating driving of the movable member 16 in the housing 11, for example, by scroll movement of the movable member in the housing, The communication chamber may be pressurized or depressurized.

DESCRIPTION OF SYMBOLS 1 Fuel remaining amount detection apparatus, 2 Fuel tank, 3 Tank chamber, 3a Hollow part, 4 Fuel 10 Accumulator, 11 Housing, 12 External space, 13 Communication chamber, 15 Drive source, 16 Movable member, 17 Drive motor, 18 Pinion, 19 rack, 20 1st piping, 21 1st passage, 22 2nd piping, 23 2nd passage, 30 1st on-off valve, 32 2nd on-off valve, 40 detection control unit (decompression processing means / pressurization processing means / repetition) 42 pressure sensor, 44 control circuit, 45 memory, Dp pressurization direction, Dr pressure reduction direction, Pth threshold, Vf Fuel remaining amount

Claims (3)

A housing that forms a communication chamber communicating with the tank chamber in the fuel tank;
A movable member that pressurizes and depressurizes the communication chamber by being driven in the housing;
A first on-off valve that opens and closes between the communication chamber and the tank chamber;
A second on-off valve that opens and closes between the communication chamber and the outside of the housing;
A detection control unit that controls the movable member and the first and second on-off valves to detect the remaining amount of fuel in the tank chamber;
With
The detection control unit includes:
The communication chamber and the tank chamber are closed by the first opening / closing valve, and the communication chamber and the outside of the fuel housing are opened by the second opening / closing valve, and the communication chamber is decompressed by the movable member. And decompression processing means for introducing air from outside the housing into the communication chamber;
After the decompression processing by the decompression processing means, the first on-off valve opens the communication chamber and the tank chamber and the second on-off valve closes the communication chamber and the outside of the housing. Pressurization processing means for measuring the pressure value of the tank chamber by pressurizing the communication chamber with the movable member;
Repetitive processing means that repeats the decompression process by the decompression process means and the pressurization process by the pressurization process means until the pressure value measured by the pressurization process means becomes a predetermined threshold value or more;
A remaining amount calculating unit that calculates the remaining amount of fuel based on a pressure value that is equal to or greater than the threshold when the pressure value measured by the pressurizing unit is equal to or greater than the threshold;
A fuel remaining amount detecting device characterized by comprising: The sum of the volume of the cavity portion in the tank chamber and the volume of the communication portion including the communication chamber, which is a portion communicating with the tank chamber, is defined as a spatial volume that changes according to the remaining fuel amount,
When the sum of the space volume and the fuel remaining amount at the time of measuring a pressure value equal to or greater than the threshold is defined as a predetermined overall volume,
2. The fuel remaining amount calculating unit according to claim 1, wherein the remaining amount calculating unit calculates the remaining fuel amount by subtracting the space volume correlated with a pressure value equal to or greater than the threshold value from the total volume. Detection device.   The first on-off valve receives the pressure of the communication chamber that is depressurized by the movable member and closes the space between the communication chamber and the tank chamber, while reducing the pressure of the communication chamber that is pressurized by the movable member. The fuel remaining amount detecting device according to claim 1, wherein the fuel remaining amount detecting device is a check valve that receives and opens between the communication chamber and the tank chamber.

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