JP5561181B2 - Fuel level measuring device - Google Patents

Description

  The present invention relates to a fuel remaining amount measuring device, and more particularly to a fuel remaining amount measuring device that can accurately detect the level of fuel in a fuel tank even when the vehicle is tilted in the vehicle front-rear direction or the left-right direction. .

  Conventionally, there are various types of fuel remaining amount measuring devices provided in a fuel tank of an automobile or the like, and as one of them, using a vertically long detection electrode (sensor) extending in the vehicle vertical direction, A configuration is employed in which the position where the detection electrode contacts the fuel is detected to detect the liquid level.

  For example, a combination of a reference electrode in which the detection unit is always immersed in the liquid, a gas-phase electrode that is always outside the liquid, and a liquid surface electrode that intersects the liquid surface, and the capacitance due to contact / non-contact between the electrode and the liquid The structure which detects a liquid level from the change of is proposed (patent document 1).

However, depending on the shape of the fuel tank 100 as shown in FIG. 8, the liquid level F when the tank is full is the fuel tank 100 because the mounting port 22 is provided near the center (plan view) of the fuel tank 100. If the liquid level sensor 114 is installed at the center of the fuel tank 100, the liquid level at the time of full tank cannot be detected.

  For this reason, as shown in FIG. 9, if the liquid level sensor 114 is installed at the end of the fuel tank 100 in the front-rear direction, the left-right direction, etc. When the liquid level is inclined, the liquid level sensor 114 provided at the end portion cannot accurately detect the liquid level, and there is a problem that a large meter needle shake occurs.

As a liquid level detector for a fuel tank that avoids this problem, for example, a housing that forms a liquid level monitor chamber that communicates with the tank, and a detection means that detects the liquid level of a chamber similar to the liquid level, consists of a closing means for opening and closing a communication passage between the tank and the liquid level monitoring chamber, said opening and closing means for closing the movable cone, the communicating path when the movable cone is displaced from the reference position There is a liquid level detector comprising an on-off valve mechanism (Patent Document 2).

JP 2010-025782 A JP 63-091520 A

  However, the liquid level detector has a problem that its structure is complicated because the valve mechanism is composed of a valve body, a spherical cone, and a housing.

  The present invention has been made to solve the above problem, and has a simple structure. Even when the vehicle is tilted in the vehicle front-rear direction or the left-right direction, the liquid level of the fuel in the fuel tank can be reduced. An object of the present invention is to provide a fuel remaining amount measuring device that can be accurately detected.

The invention according to claim 1 is provided in a vehicle, and has a cylindrical main body portion erected on the bottom surface of a fuel tank in which fuel is stored, and is disposed inside the main body portion. A liquid level sensor that measures the liquid level of the fuel, a float storage chamber that is provided at a lower end of the main body, and that has a flow path that communicates the main body with the fuel tank, and is moved to the float storage chamber A float that is rotatably accommodated and moves or rotates in the float housing chamber when the inclination of the fuel tank from the horizontal reaches a predetermined angle or more, and closes the flow path of the float housing chamber . It is a plate-like float in which one or a plurality of flow paths are formed along the thickness direction, and the float accommodation chamber contains the plate-like float so as to be movable along a surface direction, and the float accommodation chamber Flow Will flow path communicating with said plate-like float when the tilt is equal to or less than the predetermined angle of the fuel tank.

  In the fuel remaining amount measuring device, when the vehicle is not inclined, the flow path of the float accommodation chamber is in an open state, so that the fuel tank and the main body communicate with each other through the flow path of the float accommodation chamber. Has been. Accordingly, the fuel level in the fuel tank is the same as that in the main body, so that the fuel level measured by the level sensor is the same as the level in the fuel tank.

Here, if the fuel tank is inclined from the horizontal by a predetermined angle or more, the float moves or rotates in the float housing chamber and the flow path is closed, so that the flow of fuel between the fuel tank and the main body is substantially reduced. Refused. Therefore, in the main body, the fluctuation of the liquid level due to the inclination of the liquid level in the fuel tank is suppressed.
Further, in the fuel remaining amount measuring apparatus, when the vehicle is not inclined, the flow path of the float housing chamber and the flow path of the plate-like float communicate with each other. In communication.
Here, when the fuel tank is inclined at a predetermined angle or more as in the case where the vehicle is parked on a sloping ground, the plate-like float moves along the surface direction by the buoyancy received from the fuel in the float housing chamber, The flow path of the float storage chamber is closed by the plate float. As a result, the communication between the main body and the fuel tank is interrupted, so that fluctuations in the liquid level due to the inclination of the liquid level in the fuel tank are suppressed in the main body.

According to a second aspect of the present invention, the upper surface of the float has a spherical shape recessed upward, and the ceiling surface of the float storage chamber corresponds to the curvature of the upper surface of the float and is concaved upward. The present invention relates to a fuel remaining amount measuring device according to claim 1 .

  In the fuel remaining amount measuring device, when the fuel tank is inclined at a predetermined angle or more, the plate-like float is around the center point of the virtual sphere in which the upper surface of the plate-like float forms a part in the float housing chamber. Make a rotating motion. Thereby, the flow path of the float accommodation chamber is closed by the plate-like float.

  According to the first aspect of the present invention, the remaining amount of fuel that has a simple structure and that can accurately detect the level of the fuel in the fuel tank even when the vehicle is tilted in the front-rear direction or the left-right direction of the vehicle. A measuring device is provided.

Further, according to the invention of claim 1, simpler remaining fuel amount measuring device compared to configure the remaining fuel amount measuring device with a spherical float is provided as float.

3. The fuel remaining amount measuring apparatus according to claim 2 , wherein when the fuel tank is inclined at a predetermined angle or more, the plate-like float is centered on a virtual sphere whose upper surface forms part of the plate-like float in the float housing chamber. Move around the point.

Therefore, according to the second aspect of the present invention, the remaining fuel amount measuring device with less resistance when the plate-like float moves compared to the remaining fuel amount measuring device in which the plate-like float moves along the surface direction. Is provided.

FIG. 1 is a schematic cross-sectional view illustrating a configuration of a fuel tank having a fuel remaining amount measuring apparatus according to the first embodiment. FIG. 2 is a schematic cross-sectional view showing the configuration of the fuel remaining amount measuring apparatus according to the first embodiment. FIG. 3 is a schematic diagram illustrating a configuration of a liquid level sensor provided in the fuel remaining amount measuring apparatus according to the first embodiment. FIG. 4 is an explanatory diagram illustrating the operation of the fuel remaining amount measuring apparatus according to the first embodiment. FIG. 5 is a schematic cross-sectional view showing a configuration of a fuel tank having a fuel remaining amount measuring apparatus according to the second embodiment. FIG. 6 is a schematic cross-sectional view illustrating the configuration of the fuel remaining amount measuring apparatus according to the second embodiment. FIG. 7 is an explanatory view showing the operation of the fuel remaining amount measuring apparatus according to the second embodiment. FIG. 8 is a side sectional view showing a fuel tank equipped with a conventional fuel remaining amount measuring apparatus. FIG. 9 is a side sectional view showing a fuel tank equipped with a conventional fuel remaining amount measuring device.

1. Embodiment 1
Hereinafter, an example of a fuel tank provided with a fuel remaining amount measuring apparatus according to a reference example will be described with reference to the drawings. In FIG. 1 and subsequent figures, the arrow UP indicates the upward direction of the vehicle body.

  The fuel tank 10 is a container having a substantially box shape as shown in FIG. 1, and its shape is determined by the shape of a vehicle body or the like to be installed and the component arrangement. The material of the fuel tank 10 is selected in consideration of resistance to corrosion by fuel (gasoline etc.), mechanical strength, impact resistance and safety in the event of a collision.

  A mounting port 22 for a pump module or the like is provided on the upper side of the vehicle body of the fuel tank 10, and is sealed with a lid portion 28 that closes the mounting port 22 from the outside so that the fuel inside does not leak out. The mounting port 22 protruding in a cylindrical shape above the vehicle is sealed with a lid portion 28, and the lid portion 28 is fixed with a screw lid 120 screwed with a male screw provided on the outer peripheral surface of the mounting port 22.

  At this time, if the mounting port 22 protrudes from the box-shaped fuel tank 10, space efficiency may be reduced when the mounting port 22 is assembled to the vehicle body. Therefore, the mounting port 22 should be provided so as to be submerged inside the fuel tank 10. desirable. In this case, it is necessary to provide a space in the fuel tank 10 in which the attachment port 22 and the screw lid 120 can be cleared.

  Accordingly, a concave portion 24 having a concave outer surface is formed on the upper surface of the vehicle body of the fuel tank 10, and an inner portion of the concave portion 24 is formed as a convex portion 26 protruding toward the lower side of the vehicle body inside the fuel tank 10. Therefore, when the fuel tank 10 is filled with fuel, the liquid level F exceeds the height of the convex portion 26, and the convex portion 26 is immersed in the fuel.

  The fuel tank 10 is generally formed of a steel plate or resin, and a vapor layer is secured by a method such as providing unevenness on the upper side surface of the vehicle body as shown in FIG. In other words, the volatile fuel evaporates due to the outside air temperature or heat from the engine or the like, and fills the voids in the fuel tank 10 as volatile gas (vapor). If the entire tank is filled with fuel at this time, the generated volatile gas of the fuel loses escape and the inside of the fuel tank 10 is pressurized. In order to prevent this, a certain amount of air gap (vapor layer) is set in the upper part of the fuel tank 10 to secure a escape space for volatile gas pressure.

  Further, in the fuel tank 10 that secures the vapor layer as described above, pressurization and depressurization are continuously repeated by the fuel temperature up and down (the influence of the temperature, the heat from the road surface and the exhaust pipe) and the fuel consumption, Mechanical stress continues to be applied. For this reason, making the upper surface of the fuel tank 10 into a complicated uneven shape increases the mechanical strength of the fuel tank 10 itself, and also has a meaning as a countermeasure against changes in internal pressure.

  Further, a pump unit (not shown) may be provided inside the fuel tank 10, and the internal fuel may be pumped out by a pump and sent out to the outside by a fuel hose (not shown).

As shown in FIG. 1, a liquid level gauge 1 as an example of a fuel remaining amount measuring apparatus according to a reference example is erected from a position where the convex portion 26 on the bottom surface 20 of the fuel tank 10 can be cleared upward from the vehicle. . As shown in FIG. 1, the liquid level gauge 1 has an upper end projecting above the vehicle level above the liquid level F when the fuel tank 10 is horizontal.

  As shown in FIG. 2, the liquid level gauge 1 is provided with a cylindrical main body 11, a liquid level sensor 14 provided inside the main body 11, and a spherical float described later. And a float storage chamber 13 that rotatably stores 12 around a center point. The liquid level measurement chamber 15 which is a part in which the liquid level sensor 14 is provided in the main body, and the partition wall 16 that partitions the float storage chamber 13 and the liquid level measurement chamber 15 are provided.

  The spherical float 12 as a whole is made of a resin material such as polyacetal resin, polyphenylene sulfide resin, aliphatic polyamide resin, etc., which has a specific gravity substantially the same as that of fuel and does not swell with fuel. As shown in FIG. 2, a linear flow path 12A passing through the center point is formed, and a weight 12B is embedded in the vicinity of one end of the flow path 12A.

  The vehicle lower side of the float chamber 13 is closed by a lid 18 provided with a conduction hole 18A.

  The partition wall 16 communicates with the flow path 12A of the spherical float 12 when the inclination θ of the fuel tank 10 from the horizontal is equal to or less than an allowable angle φ, which is an angle at which the needle of the fuel gauge can be allowed to swing as shown in FIG. A flow path 17 is formed.

  The liquid level sensor 14 has, for example, a structure in which an electrode 14D is provided on the surface of a base 14E formed of a foldable insulator such as a resin film whose longitudinal direction is the vehicle vertical direction as shown in FIG. The static capacity for detecting the remaining amount of fuel remaining in the fuel tank 10 based on the electric capacity that varies depending on the length of the electrode 14D in contact with fuel such as gasoline and the length of the portion in contact with air. It is a capacitance sensor.

  In the liquid level sensor 14, the electrode 14D includes a fuel reference measurement unit 14A that is always immersed in fuel, a reference measurement unit 14C that is always positioned above the liquid level F when the tank is full, and a fuel reference. It is located between the measurement unit 14A and the reference measurement unit 14C, and is divided into a liquid level measurement unit 14B that measures the fuel level of the fuel tank 10.

  As shown in FIG. 3B, the electrode 14D includes a common lead wire 14F connecting the fuel reference measurement unit 14A, the liquid level measurement unit 14B, and the reference measurement unit 14C, and the fuel reference measurement unit 14A and the liquid level measurement unit. 14B and an output lead 14G that outputs electrostatic capacitances in the reference measuring unit 14C, a comb-like electrode 14H that protrudes in a horizontal direction at a predetermined interval from the common lead 14F, and an output lead 14G. And a comb-like electrode 141 protruding in a horizontal direction at a predetermined interval. The comb electrodes 14H and the comb electrodes 14I are alternately arranged.

  As a method of electrically detecting the liquid level, for example, there is a method of measuring the capacitance between the electrodes 14D. When the fuel in the fuel tank is exhausted, the space between the electrodes 14D becomes occupied by what was previously occupied by the fuel, and the capacitance decreases. Therefore, it can be detected that the fuel has become empty by detecting the decrease in the capacitance. At this time, more accurate detection is performed by comparing the measured values based on the values detected by the reference measurement unit 14C provided in the air in advance and the fuel reference measurement unit 14A always present in the liquid. be able to.

  The common lead wire 14F and the output-side lead wire 14G in the electrode 14D are electrically connected to the outside through a terminal 14J provided at the end of the liquid level sensor 14, and are detected by, for example, an external electric circuit. The liquid level is transmitted outside the fuel tank 10 as fuel amount information.

Hereinafter, the operation of the liquid level gauge 1 will be described with reference to FIG.
The spherical float 12 is accommodated in the float accommodation chamber 13 so as to be freely rotatable around the center point. A weight 12B is embedded in the vicinity of one end of the flow path 12A. Therefore, as shown in FIGS. 4A and 4B, the spherical float 12 rotates inside the float housing chamber 13 so that the side on which the weight 12B is embedded is always located on the lower side. The flow path 12A always faces the vertical direction.

  Therefore, when the fuel tank 10 is horizontal, the flow path 17 provided in the partition wall 16 of the main body 11 and the flow path 12A of the spherical float 12 communicate with each other as shown in FIG. The liquid level measurement chamber 15 and the inside of the fuel tank 10 communicate with each other. As a result, the fuel level in the level gauge 1 is equal to the fuel level in the fuel tank 10.

  When the vehicle inclines for some reason and the fuel tank 10 inclines from the horizontal by the inclination θ, the main body 11 of the liquid level gauge 1 also inclines by the angle θ from the state of FIG. On the other hand, the spherical float 12 rotates inside the float storage chamber 13 so that the flow path 12A always faces the vertical direction. Therefore, when the inclination θ of the fuel tank 10 exceeds the allowable angle φ, the flow path 17 of the partition wall 16 is closed by the spherical float 12 as shown in FIG. Communication with is cut off. As a result, even if the fuel tank 10 is tilted, the fuel level in the liquid level measurement chamber 15 is maintained at a height at which the tilt θ of the fuel tank 10 does not exceed the allowable angle φ.

2. Embodiment 2
Hereinafter, another example of the fuel tank provided with the fuel remaining amount measuring device of the present invention will be described with reference to the drawings. In FIG. 5 and subsequent figures, the same reference numerals as those in FIGS. 1 to 4 denote the same components as those shown in FIGS. 1 to 4 unless otherwise specified.

  As shown in FIG. 5, a liquid level gauge 2 as another example of the fuel remaining amount measuring device of the present invention is erected from a position where the convex portion 26 on the bottom surface 20 of the fuel tank 10 can be cleared upward from the vehicle. Yes. As shown in FIG. 5, the liquid level gauge 2 has an upper end protruding above the vehicle from the liquid level F when the fuel tank 10 is horizontal when the tank is full.

  As shown in FIG. 6, the liquid level gauge 1 is provided at a cylindrical main body 11, a liquid level sensor 14 provided inside the main body 11, and a lower end of the main body 11, and is a plate shape described later. A float storage chamber 13 for storing a float 19; a liquid level measurement chamber 15 which is a portion provided with a liquid level sensor 14 in the main body; a partition wall 16 partitioning the float storage chamber 13 and the liquid level measurement chamber 15; Is provided.

  The partition wall 16 has a spherical shape protruding upward. A flow path 17 is opened at the top of the partition wall 16.

The float storage chamber 13 is provided with a guide 21 for guiding the float 19 in the surface direction, which has a spherical shape protruding upward corresponding to the partition wall 16.

  The plate-like float 19 has a substantially disk shape having an outer diameter smaller than the inner diameter of the float chamber 13 and is made of a material having a specific gravity smaller than that of the fuel. The upper surface has a spherical shape corresponding to the shape of the lower surface of the partition wall 16, and the lower surface has a spherical shape corresponding to the upper surface of the guide 21. A channel 19 </ b> A is formed in the center of the plate-like float 19 along the thickness direction.

  The liquid level sensor 14 is as described in the first embodiment.

Hereinafter, the operation of the liquid level gauge 2 will be described with reference to FIG .
As described above, the plate-like float 19 is made of a material having a specific gravity smaller than that of the fuel and has an outer diameter smaller than the inner diameter of the float housing chamber 13. Therefore, as shown in FIG. 7A, the float floats in a state where the upper surface is in contact with the lower surface of the partition wall 16 in the float storage chamber 13 by buoyancy from the fuel.

  Therefore, when the fuel tank 10 is horizontal, the plate-shaped float 19, the flow path 19A, and the flow path 17 of the partition wall 16 are in communication with each other as shown in FIG. Since the position measuring chamber 15 communicates with the inside of the fuel tank 10, the fuel level in the level gauge 2 and the fuel level in the fuel tank 10 are equal.

  When the vehicle inclines for some reason and the fuel tank 10 also inclines from the horizontal by the inclination θ, the main body 11 of the level gauge 2 also inclines by the angle θ from the state of FIG. On the other hand, the plate-like float 19 moves from the center of the float accommodation chamber 13 toward the side wall by moving upward in the float accommodation chamber 13 along the lower surface of the partition wall 16. Therefore, when the inclination θ of the fuel tank 10 exceeds the allowable angle φ, the flow path 17 of the partition wall 16 is closed by the plate-shaped float 19 as shown in FIG. Communication with the inside is broken. As a result, even if the fuel tank 10 is tilted, the fuel level in the liquid level measurement chamber 15 is maintained at a height at which the tilt θ of the fuel tank 10 does not exceed the allowable angle φ.

  Since the level gauge 2 in the second embodiment uses a plate-like float 19 made of a homogeneous material as a float, the flow level is compared with the liquid level gauge 1 in the first embodiment using a spherical float 12 as the float. Can be simplified.

DESCRIPTION OF SYMBOLS 1 Liquid level gauge 2 Liquid level gauge 10 Fuel tank 11 Main body part 12 Spherical float 12A Flow path 12B Weight 13 Float accommodation chamber 14 Liquid level sensor 14A Fuel reference measurement part 14B Liquid level measurement room 14C Reference | standard measurement part 14D Electrode 14E Base 14F Common Lead wire 14G Output side lead wire 14H Comb electrode 14I Comb electrode 14J Terminal 15 Liquid level measurement chamber 16 Partition 17 Channel 19 Plate-shaped float 19A Channel 20 Bottom

Claims (2)

A cylindrical main body provided on a vehicle and standing on the bottom of a fuel tank in which fuel is stored;
A liquid level sensor which is disposed inside the main body and measures the liquid level of the fuel inside the main body;
A float housing chamber provided at a lower end of the main body, and having a flow path communicating the main body with the fuel tank;
A float that is movably or rotatably housed in the float housing chamber, and that moves or rotates in the float housing chamber to close the flow path of the float housing chamber when the inclination of the fuel tank from a horizontal angle exceeds a predetermined angle;
With
The float is a plate-like float in which one or a plurality of flow paths are formed along the thickness direction,
The float accommodation chamber accommodates the plate-like float so as to be movable along a plane direction, and the flow path of the float accommodation chamber is configured so that the inclination of the fuel tank is equal to or less than the predetermined angle. Fuel remaining amount measuring device communicating with the flow path . The upper surface of the float has a spherical shape recessed upward, and the ceiling surface of the float storage chamber has a curvature corresponding to the curvature of the upper surface of the float and has a spherical shape recessed upward. The fuel remaining amount measuring apparatus according to claim 1 .

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