JP2018105780A - Liquid level detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detector which can be set in a fuel tank easily due to its simple structure without requiring a significant change according to a shape of the fuel tank.SOLUTION: A fuel gauge 1 is set in a fuel tank 2, and includes a motor 3 and a measuring fin 4. The motor 3 is connected to an ammeter 6, a detection switch 7, and a battery 8. The ammeter 6 and the detection switch 7 are connected to the controller 9. The measurement fin 4 has a pressure receiving surface 4a for receiving resistance from gasoline G when being rotated by the motor 3. An operation unit 11 of the controller 9 detects a current which is applied to the motor 3 by the ammeter 6 when the measurement fin 4 is rotated, and calculates a liquid level L of the gasoline G from an output signal from the ammeter 6.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid level detection device that detects a liquid level of a fuel tank such as a fuel tank of a vehicle.

  Conventionally, in a fuel tank such as a fuel tank provided in a vehicle, a liquid level detection device is provided in order to measure the remaining amount of liquid in the tank. Conventional liquid level detection devices generally measure the fuel level by detecting the fuel level with a float attached to one end of an arm (see Patent Document 1).

JP-A-9-33323

  Such a conventional apparatus has various shapes of the fuel tank, so that it is necessary to design it in accordance with the shape of the fuel tank, and there is a disadvantage that the design cost and the manufacturing cost of the product increase. In addition, when installing a conventional device in a fuel tank, it is necessary to install the device by inserting it into the fuel supply port of the tank or the like. However, since the shape of the device is complicated, the installation work is difficult. was there.

  An object of the present invention is to improve a liquid level detection device that detects a liquid level in a fuel tank, and more specifically, to provide a liquid level detection device that does not require a large change in accordance with the shape of the fuel tank. And Another object of the present invention is to provide a liquid level detection device that has a simple configuration and can be easily installed even when installed in a fuel tank.

  The liquid level detection device of the present invention is a liquid level detection device that detects the liquid level of liquid fuel in a fuel tank of a moving body, and is inserted into the liquid fuel in the fuel tank in order to eliminate the above inconvenience. A load detection body, a drive unit that rotates the load detection body, a load detection unit that detects a load when the load detection unit is driven by the drive unit, and an output value of the load detection unit The load detection body has a pressure receiving surface that is directed in the rotation direction and receives pressure from the liquid during rotation, and the calculation unit is based on an output value from the load detection unit. Then, the liquid level is calculated.

  When the load detection body is rotated by the drive unit, the load for moving the load detection body increases or decreases in proportion to the depth at which the pressure receiving surface is immersed in the liquid. Therefore, by detecting the load generated in the load detection body by the load detection section and calculating based on the output value by the calculation section, the depth at which the load detection body is immersed in the liquid, that is, in the fuel tank The liquid level of the liquid can be calculated.

  As described above, the liquid level detection device of the present invention has a simple configuration of a load detection body having a pressure receiving surface as a configuration for detecting the liquid level of the liquid, and thus requires an arm and a float as in the conventional case. do not do. Therefore, the liquid level detection device of the present invention does not need to be greatly changed according to the shape of the fuel tank, and the installation work is facilitated even when installed in the fuel tank.

  In the liquid level detection device of the present invention, the drive unit includes a motor that rotates the load detection body, the load is a drive current of the motor, and the load detection unit calculates a drive current of the motor. A current detection unit for detection may be provided, and the liquid level may be calculated based on an output value from the current detection unit.

  The drive unit includes a motor that rotates the load detection body, and the load is distortion generated in the load detection body when the load detection body is rotated, and the load detection unit includes the load detection unit. A strain detection element that detects strain generated in the body may be provided, and the liquid level may be calculated based on an output value from the strain detection element.

  According to this configuration, since the load detection unit can be a general-purpose ammeter or a strain gauge, it is possible to reduce the cost with a simple configuration.

  In the liquid level detection device of the present invention, it is preferable that the drive unit is driven for a predetermined time when the liquid level is calculated by the calculation unit. According to this configuration, since the drive unit is driven only when the liquid level needs to be detected, the time during which the liquid in the fuel tank is driven by driving the drive unit can be minimized. Here, the predetermined time refers to a time for acquiring load data necessary for calculating the liquid level by the calculation unit. In general, when the liquid is agitated, etc., the viscosity changes, so that the driving load of the load detector is also affected. However, this configuration can minimize the change in the viscosity of the liquid in the fuel tank. it can. Further, energy consumption for driving the drive unit can be suppressed as much as possible.

  The liquid level detection device of the present invention further includes a temperature detection unit that detects the temperature in the fuel tank, and the calculation unit calculates a correction value based on an output value from the temperature detection unit, It is preferable that the calculated value of the position is corrected with the correction value. The viscosity of liquid generally changes with temperature, but with this configuration, even if the temperature of the liquid in the fuel tank changes, the calculation unit corrects the temperature, so that the liquid level can always be detected accurately. Become.

  Further, in the liquid level detection device of the present invention, the drive unit is attached to the top surface side of the fuel tank, and the load detector is attached so as to be vertical when the fuel tank is in a basic posture. It is preferable that According to the said structure, the attachment to a fuel tank of a drive part becomes easy. Furthermore, since the load detection body is vertical and gravity in the bending direction does not occur in the load detection body, unnecessary load does not occur in the load detection body and the drive unit.

  Further, in the liquid level detection device of the present invention, the fuel tank is provided with an opening provided on the top surface side and a lid for closing the opening, and the load detector is connected to the opening from the opening. It is preferable that it is formed so as to be insertable into a fuel tank, and the drive part is attached to the lid part. According to the said structure, the operation | work at the time of installing a liquid level detection apparatus in a fuel tank becomes easy, and an operation | work becomes easy also at the time of the maintenance of a liquid level detection apparatus.

  Further, in the liquid level detection device of the present invention, the fuel tank is provided with a reserve portion formed in a concave shape on the bottom surface, and is installed so that a lower end portion of the load detection body is located in the reserve portion. Is preferred. According to this configuration, even when the liquid in the fuel tank is reduced and remains only in the reserve portion, the liquid level can be detected by the load detector.

  Moreover, in the liquid level detection apparatus of this invention, it is preferable that the said load detection body is arrange | positioned in the center part by planar view of the said fuel tank. According to the said structure, even if it is a case where the said fuel tank inclines, the influence of the inclination of the liquid level in a fuel tank can be suppressed as much as possible.

(A) is explanatory drawing which shows the structure of the fuel meter of 1st Embodiment, (B) is sectional drawing of a measurement fin. Explanatory drawing which shows the structure of the fuel meter of 2nd Embodiment. Explanatory drawing which shows the structure of the fuel meter of 3rd Embodiment.

  Next, a fuel gauge (liquid level detection device) that is an example of an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a fuel gauge used in a fuel tank for a vehicle (not shown) such as a motorcycle will be described as an example.

  As shown in FIG. 1 (A), the fuel gauge 1 of this embodiment is installed in a fuel tank 2 and includes a motor (drive unit) 3 and a measuring fin (load detector) 4. . The motor 3 is connected to an ammeter 6, a detection switch 7, and a battery 8, which are load detection units, by a harness 5. The ammeter 6 and the detection switch 7 are connected to the controller 9.

  The controller 9 is provided with a drive control unit 10 for turning on / off the detection switch 7 and a calculation unit 11 for calculating a liquid level L of the gasoline G in the fuel tank 2 from a signal transmitted from the ammeter 6. Yes. The controller 9 is composed of a microcomputer including a CPU, a memory and other electronic devices.

  In this embodiment, the motor 3 uses a brushless DC motor, and the drive shaft 12 is connected to the measuring fin 4. A current is applied to the motor 3 from the battery 8 via the ammeter 6 and the detection switch 7. The motor 3 is fixed to the inner surface (top surface) of the top plate 2 a of the fuel tank 2.

  The measuring fin 4 is a synthetic resin molded product, and is formed of a long plate-like member extending in the vertical direction from the vicinity of the top plate 2a of the fuel tank 2 to the vicinity of the bottom plate 2b as shown in FIG. Has been. In addition, as shown in FIG. 1B, the measuring fin 4 has a cross shape when viewed from the axial direction of the motor 3. The measuring fin 4 has a pressure receiving surface 4 a that receives resistance from the gasoline G in the fuel tank 2 when rotated by the motor 3. In FIG. 1B, reference numeral 4 a is attached to one surface of the measuring fin 4, but all surfaces that receive the resistance of the gasoline G by the rotation of the measuring fin 4 become the pressure receiving surfaces 4 a.

  In the fuel gauge 1 of the present embodiment, when detecting the liquid level L of the gasoline G, the drive control unit 10 of the controller 9 turns on the detection switch 7 for a predetermined time (for example, 1.0 second). When the detection switch 7 is turned on, the current from the battery 8 is applied to the motor 3, the motor 3 rotates, and the measuring fin 4 is driven and rotated by the drive shaft 12. After the elapse of the predetermined time, the detection switch 7 is turned off by the drive control unit 10 and the rotation of the motor 3 is stopped.

  When the measuring fin 4 rotates, since the measuring fin 4 is inserted into the gasoline G, a rotational resistance corresponding to the height of the liquid level L of the gasoline G is generated. The rotational resistance of the measuring fin 4 is detected by a current applied to the motor 3.

  When the liquid level L of the gasoline G is high, the portion where the measuring fins 4 are immersed in the gasoline G increases, so that the rotational resistance of the motor 3 increases. In this case, since the motor 3 requires a high torque to rotate the measuring fin 4, the current applied to the motor 3 becomes large.

  Conversely, when the liquid level L of the gasoline G is low, the portion in which the measuring fins 4 are immersed in the gasoline G decreases, so that the rotational resistance of the motor 3 decreases. In this case, since the motor 3 can rotate the measuring fin 4 with a low torque, the current applied to the motor 3 becomes small.

  In the calculation unit 11 of the controller 9, the current applied to the motor 3 when the measuring fin 4 is rotated is detected by the ammeter 6, and the liquid level L of the gasoline G is calculated from the output signal of the ammeter 6. . As described above, according to the fuel gauge 1 of the present embodiment, the liquid level L of the gasoline G in the fuel tank 2 can be detected with the configuration of the motor 3, the measuring fin 4, the detection switch 7, the ammeter 6, and the controller 9. .

  Among them, the motor 3 and the measuring fin 4 are installed in the fuel tank 2, and the measuring fin 4 is formed of a plate-like member having a cross shape when viewed in the axial direction. Thus, the fuel gauge 1 of this embodiment does not become bulky like a conventional fuel gauge having an arm and a float.

  Therefore, when the motor 3 and the measuring fin 4 are installed in the fuel tank 2, an attachment hole through which the motor 3 and the measuring fin 4 can pass is provided in the top plate 2a of the fuel tank 2, and both members are connected to the fuel tank from there. It can be installed by inserting into 2 and closing the mounting hole. As described above, the fuel gauge 1 of the present embodiment is easy to install in the fuel tank 2 unlike the conventional fuel gauge having an arm and a float.

  Next, a fuel gauge according to a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 2, the fuel gauge 1 a of the second embodiment is provided on the back surface of a cap 21 that is detachably attached to the top plate 20 a of the fuel tank 20, and includes the motor 3 and the measuring fin 4. I have. In the second embodiment, the driving load of the motor 3 is detected not by the ammeter but by the strain detection unit 13 provided on the driving shaft 12 of the motor 3 as the load detection unit.

  The strain detector 13 detects a twist applied to the drive shaft 12 by a strain gauge (not shown) as a strain detection element, and detects torque applied to the drive shaft 12. Further, in the second embodiment, the temperature sensor 14 is provided in the vicinity of the lower end portion of the measuring fin 4. The output signal of the temperature sensor 14 is transmitted to the calculation unit 11a of the controller 9a.

  Further, a reserve portion 20 c is formed on the bottom plate 20 b of the fuel tank 20. The reserve portion 20c has a shape protruding downward from the bottom surface of the fuel tank 20, and when the remaining fuel is low, the remaining fuel is collected in the reserve portion 20c. In the fuel gauge 1a of the second embodiment, the lower end portion of the measuring fin 4 is inserted into the reserve portion 20c.

  In addition, since the other structure of the fuel gauge 1a of 2nd Embodiment is the same as that of the fuel gauge 1 of the said embodiment, the same code | symbol as the said embodiment is attached | subjected and detailed description is abbreviate | omitted.

  When the fuel gauge 1a of the second embodiment detects the liquid level L of the gasoline G, the drive controller 10a of the controller 9a turns on the detection switch 7 for a predetermined time. When the detection switch 7 is turned on, the current from the battery 8 is applied to the motor 3, the motor 3 rotates, and the measuring fin 4 is driven and rotated by the drive shaft 12.

  When the measuring fin 4 rotates, a rotational resistance is generated in the measuring fin 4 according to the height of the liquid level L of the gasoline G, and a driving load applied to the driving shaft 12 by the strain detection unit 13 provided on the driving shaft 12, that is, Torque is detected. In the calculation part 11a of the controller 9a, the liquid level L of the gasoline G is calculated from the output signal of the distortion detection part 13.

  On the other hand, the output signal of the temperature sensor 14 is also transmitted to the calculation part 11a. Since the viscosity of a liquid such as gasoline G changes depending on the temperature, the driving load of the measuring fin 4 varies depending on the temperature even at the same liquid level L. In the fuel meter 1 of the second embodiment, the calculation unit 11a corrects the calculated liquid level L of the gasoline G in consideration of the difference between the reference temperature and the temperature detected by the temperature sensor 14. Yes. Therefore, the fuel gauge 1 of the second embodiment can accurately detect the liquid level L of the gasoline G regardless of changes in ambient temperature.

  Further, in the fuel gauge 1 of the second embodiment, since the lower end portion of the measuring fin 4 is inserted into the reserve portion 20c, the gasoline G in the fuel tank 20 is reduced and only remains in the reserve portion 20c. Even in this case, the liquid level L of the gasoline G in the reserve part 20c can be detected by the measuring fins 4.

  Next, a fuel gauge according to a third embodiment of the present invention will be described with reference to FIG. As shown in FIG. 3, in the fuel gauge 1 b of the third embodiment, the motor 3 and the fuel tank 2 are installed at the center position of the fuel tank 2 in the horizontal direction (X direction and Y direction in FIG. 3). The measuring fins 4 are installed so as to be in the vertical direction (Z direction in FIG. 3) in a state where the vehicle is in the basic posture.

  Since the other configuration is the same as that of the fuel gauge 1 of the above-described embodiment, the configuration of the controller and the like is omitted in FIG. 3, and the same configuration is denoted by the same reference numeral as that of the above-described embodiment. Detailed description is omitted.

  According to the fuel gauge 1b of the third embodiment, even when the vehicle (not shown) is inclined and the liquid level of the gasoline is in a state as indicated by the dotted line L ′ in FIG. Little change in liquid level. For this reason, the fuel gauge 1b can always accurately detect the level L of the gasoline G regardless of the change in the angle of the fuel tank 2 due to a change in the state of the vehicle.

  In the first to third embodiments, the motor 3 is used as the drive unit. However, the present invention is not limited to this, and any device that rotates the measuring fin 4 may be a linear motion actuator or a link mechanism. It may be a simple configuration. Even with such a configuration, the liquid level of the fuel in the fuel tank can be detected by detecting the driving load of the linear actuator and the load generated in the measuring fin 4.

  In the above embodiments, the motor 3 is installed in the fuel tanks 2 and 20, but may be installed outside the fuel tanks 2 and 20. Further, the motor 3 is not limited to a brushless DC motor, and a motor having another configuration can be used.

  The measuring fin 4 has a cruciform shape in a cross-sectional view. However, the shape is not limited thereto, and may be a semicircular shape in a cross-sectional view as long as it has a pressure-receiving surface 4a. The shape can be any shape such as a screw-like shape as a whole. In addition, the measuring fin 4 is configured to extend to the vicinity of the bottom plate 2b of the fuel tank 2. However, the measuring fin 4 may be configured to extend from the measuring fin 4 and rotatably support the bottom plate 2b.

  Moreover, in the said embodiment, although the predetermined time which rotates the measurement fin 4 is 1.0 second, this predetermined time can also be suitably set according to the performance of a load detection body. Further, during this predetermined time, the liquid level L of the gasoline G may be detected by rotating the measuring fin 4 only once, changing the rotating direction and the number of rotations, rotating the measuring fin 4 times, clockwise and counterclockwise. It may be rotated in the surrounding direction.

  Moreover, in the said 2nd Embodiment, although the example which used the distortion | strain detection element as the strain gauge was given, not only this but the thing which can detect distortion, for example, an electrostriction element (piezoelectric element), distortion, etc. Other means such as a conductive resin whose resistance varies depending on the condition may be used. The fuel gauges of the above embodiments can be widely used not only for motorcycles but also for liquid fuel fuel tanks such as four-wheeled vehicles, ships, and general-purpose machines. Further, the liquid level detection device of the present invention may be used not only for a fuel tank such as a gasoline tank but also for detecting a liquid level of a water tank, a chemical liquid tank, or the like.

  DESCRIPTION OF SYMBOLS 1,1a, 1b ... Fuel gauge, 2,20 ... Fuel tank, 3 ... Motor, 4 ... Metering fin, 6 ... Ammeter, 7 ... Detection switch, 9 ... Controller, 10, 10a ... Drive control part, 11, 11a ... Calculation unit, G ... Gasoline, L ... Liquid level.

Claims (9)

A liquid level detection device for detecting the level of liquid fuel in a fuel tank of a moving body,
A load detector inserted into the liquid fuel in the fuel tank;
A drive unit for rotating the load detector;
A load detector for detecting a load when the load detector is driven by the drive unit;
A calculation unit that calculates using the output value of the load detection unit,
The load detector has a pressure receiving surface that is directed in the rotation direction and receives pressure from the liquid during rotation,
The liquid level detection device according to claim 1, wherein the liquid level is calculated based on an output value from the load detection unit. The drive unit includes a motor that rotates the load detector.
The load is a drive current of the motor,
The load detection unit includes a current detection unit that detects a drive current of the motor,
The liquid level detection device according to claim 1, wherein the liquid level is calculated based on an output value from the current detection unit. The drive unit includes a motor that rotates the load detector.
The load is distortion generated in the load detection body when the load detection body is rotated,
The load detection unit includes a strain detection element that detects strain generated in the load detection body,
The liquid level detection device according to claim 1, wherein the liquid level is calculated based on an output value from the strain detection element.   The liquid level detection device according to claim 1, wherein the driving unit is driven for a predetermined time when the liquid level is calculated by the calculation unit. A temperature detector for detecting the temperature in the fuel tank;
5. The calculation unit according to claim 1, wherein the calculation unit calculates a correction value based on an output value from the temperature detection unit, and the liquid level calculation value is corrected by the correction value. Liquid level detection device.   The said drive part is attached to the top | upper surface side of the said fuel tank, The said load detection body is attached so that it may become perpendicular | vertical when the said fuel tank is a basic attitude. The liquid level detection device according to any one of 5. The fuel tank is provided with an opening provided on the top surface side, and a lid for closing the opening,
The liquid level detection device according to claim 1, wherein the load detection body is formed to be insertable into the fuel tank from the opening, and the drive unit is attached to the lid. . The fuel tank is provided with a reserve portion formed in a concave shape on the bottom surface,
The liquid level detection device according to claim 1, wherein the load detection body is installed so that a lower end portion of the load detection body is located in the reserve portion. The liquid level detection device according to any one of claims 1 to 8, wherein the load detection body is disposed at a central portion in a plan view of the fuel tank.

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