JP3281102B2 - Volume measuring method and volume measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a volume measuring method and a volume measuring device, and more particularly, to a small-sized reference tank provided in communication with a main tank having a predetermined shape for storing a fluid, and the space in both tanks is reduced. The present invention relates to a volume measuring method and a volume measuring device for changing the volume of a space in a main tank based on a pressure fluctuation value in both tanks.

[0002]

2. Description of the Related Art Conventionally, as a volume measuring method and an apparatus for measuring the volume of a liquid, a powder or the like stored in a tank,
Various methods and apparatuses have been proposed as described in JP-A-2-19717. For example, in the embodiment described in FIG. 10 of the publication, the main tank 30 and the correction tank 31 are made to be a completely closed system, and the two tanks are connected by a thin pipe 47 to make the static pressure equal. I have. Then, the volume in the respective tanks is changed by the volume changing mechanism 33 with respect to the main tank 30 and the correction tank 31 to cause pressure fluctuation, and the output γ · P ₀ · v ₀ from the second amplitude detector 39a is obtained. First amplitude detector 3
The volume V ₂ of the hollow portion of the main tank 30 is calculated by dividing by the output γ · P ₀ · v ₀ / V ₂ from 9b. Further and to calculate the volume V _L of the liquid or the like contained in the main tank 30 by subtracting the volume V ₂ from the total volume of the main tank 30 (volume). Since the measurement principle is described in the publication, the description is omitted, but the volume of the space in the main tank 30 (that is, the total volume of the main tank if there is no storage in the main tank, and the storage is If present, the volume other than the contents in the main tank)
And that it can be calculated according to the detection output of the pressure fluctuation in the correction tank 31.

[0003]

In the above-described volume measuring method and apparatus, it is assumed that both the main tank and the correction tank are rigid bodies, so that the tank can be deformed like a fuel tank of an automobile, for example. If applied, a measurement error will occur. In particular, the space in the fuel tank of the car is heated by the high-temperature return fuel, or changes in temperature, such as cooling after traveling,
Since the gas (fuel vapor) in the main tank expands or contracts, it is necessary to correct for the deformation of the main tank accompanying the expansion or contraction.

However, according to the method and apparatus described in the above-mentioned publications, the deformation of the main tank is processed as a constant peculiar to the tank at the time of calculation, and the expansion and contraction of the gas in the main tank as described above. This does not take into account the volume change due to the deformation of the main tank, and may still cause an error. Although the term “correction tank” is used in the above publication, in the present application,
In consideration of the function of giving the pressure fluctuation to be referred to when measuring the volume of the space in the main tank, the reference tank is used.

Accordingly, the present invention relates to a volume measuring method and a volume measuring apparatus for changing the volume of the space in the main tank and the reference tank and measuring the volume of the space in the main tank based on the pressure fluctuation value in both spaces. An object of the present invention is to suppress errors caused by deformation of the main tank due to expansion and contraction of gas in the main tank, and to ensure good measurement accuracy.

[0006]

In order to achieve the above object, the present invention provides a main tank having a predetermined shape for containing a fluid, a reference tank communicating with the main tank, a space in the reference tank, An actuator that changes the volume of each of the spaces above the fluid in the main tank to apply pressure fluctuations, and drives the actuators to change the operating state pressure fluctuation values of the main tank and the reference tank. In a volume measuring method for detecting and calculating a volume of a space in the main tank based on a ratio of each of the operating state pressure fluctuation values, the expansion of gas in the main tank is performed.
The volume of the space in the main tank is calculated by adjusting the volume in the reference tank so as to be substantially equal to the volume change rate due to the deformation of the main tank due to the contraction .

As shown in FIG. 1, the volume measuring device of the present invention has a main tank MT of a predetermined shape for storing a fluid, a reference tank ST communicating with the main tank MT, and a reference tank ST. Inside the space and main tank M
An actuator AT for changing the volume of each space in the space above the fluid in T to apply pressure fluctuation, a driving unit M3 for driving the actuator AT ,
Adjusting means BT for adjusting the volume in the reference tank ST so as to be substantially equal to the volume change rate due to the deformation of the main tank MT due to the expansion and contraction of the gas, and the pressure fluctuation value in the space above the fluid in the main tank MT. A first pressure fluctuation detecting means M1 for detecting, a second pressure fluctuation detecting means M2 for detecting a pressure fluctuation value in a space in the reference tank ST,
The main tank MT detected by the first and second pressure fluctuation detecting means M1 and M2 in a state where the actuator AT is operated.
And a calculating means M4 for calculating the volume of the space in the main tank MT based on the ratio of the operating state pressure fluctuation value of each of the reference tanks ST.

[0008]

In the above-described volume measuring method, the operating state pressure fluctuation value of each of the main tank and the reference tank is detected while the actuator is operated. Then, the ratio of the operating state pressure fluctuation values is calculated, and the volume of the space in the main tank is calculated based on the calculation result. In this case, for example, the gas in the main tank expands and contracts due to a temperature change, and the main tank may deform accordingly.However, the volume in the reference tank communicating with the main tank changes according to the volume change due to the deformation of the main tank. Adjusted to be approximately equal to the rate. Thus, the volume change due to the deformation of the main tank is offset.

Further, in the volume measuring device configured as shown in FIG. 1, when the actuator AT is driven by the driving means M3, a pressure fluctuation is applied to the spaces in the reference tank ST and the main tank MT. . On the other hand, the gas in the main tank MT expands and contracts due to, for example, a temperature change, and the main tank MT may be deformed accordingly.
The volume in T is adjusted by the adjusting means BT so as to be substantially equal to the volume change rate due to the deformation of the main tank MT, and the volume change due to the deformation of the main tank MT is canceled. Thus, while the actuator AT is operated, the first and second pressure fluctuation detecting means M1 and M2 detect the operating state pressure fluctuation values of the main tank MT and the reference tank ST. Then, the ratio of each operating state pressure fluctuation value is calculated by the calculating means M4, and the volume of the space in the main tank MT is calculated based on the calculation result.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 4 relate to an embodiment of the volume measuring apparatus according to the present invention, which is applied to a liquid amount measuring apparatus for measuring the remaining amount of fuel in a fuel tank of an automobile. The fuel tank has a main tank 1 defining a closed space. When the space MS formed above when the fuel is injected is minimum, that is, when the liquid level F
An opening 1a is formed at a position communicating with the space MS even when L becomes the highest. A cylindrical reference tank 2 is accommodated in the opening 1a, and a flange 2f formed at one end thereof is pressed into contact with the opening 1a via a gasket 3a, and furthermore, is fitted to the flange 2f via a gasket 3b. The cover 4 is pressed. Also, an adjusting device 70 described later.
Case 72 is joined to the cover 4. These case 72, cover 4, flange portion 2f and gasket 3
a, 3b are fixed to the main tank 1 by an annular retainer 1b fixed to the main tank 1 and bolts (not shown) screwed to the retainer 1b. The reference tank 2 is not housed in the main tank 1, but is arranged so that only the tip of the reference tank 2 is joined to the opening 1 a and the remaining portion projects outward from the main tank 1. Is also good.

An actuator 30 is accommodated in the reference tank 2 as shown in FIGS. The actuator 30 of the present embodiment is an electrodynamic device that converts an electric signal into a mechanical vibration of the diaphragm 31. The diaphragm 31 is supported by an opening of the reference tank 2 via an edge 31a, and a movable coil 32 is mounted at the center of the diaphragm 31. Further, a core 33 and a permanent magnet 34 joined to the core 33 are fitted into the reference tank 2, and the movable coil 32 is disposed so as to be movable with respect to the core 33 in the axial direction of the reference tank 2. A communication hole 3 is provided at the center of the core 33.
A space RS is formed in the reference tank 2 by the cover 4 and the diaphragm 31. A small-diameter communication hole 2 a is formed in the side wall of the reference tank 2, and a space RS in the reference tank 2 communicates with a space MS in the main tank 1.

When a drive signal of an AC voltage is supplied to the movable coil 32, the diaphragm 31 vibrates, and the space MS in the main tank 1 and the space RS in the reference tank 2 are simultaneously inverted. A phase compression wave is output. The actuator 30 is not limited to the above, and may be configured as an electromagnetic device that winds a coil around a core connected to a permanent magnet and supplies a drive signal to the coil to vibrate the diaphragm 31. Is also good. In addition, various configurations such as an electrostatic type, an electrostrictive type, and a magnetostrictive type used in the speaker field can be adopted, or a device for driving a piston or the like can be adopted.

The reference tank 2 is provided with an adjusting device 70 as adjusting means according to the present invention. That is, as shown in an enlarged manner in FIG.
Is formed, and a diaphragm 71 is provided so as to cover this, and its periphery is clamped between the flange portion 72 a of the case 72 and the cover 4. The case 72 has a concave portion formed in the center, and an adjusting screw 73 is screwed to the bottom thereof. A spring 74 is housed in the recess of the case 72, one end of the spring 74 is fixed to the center of the diaphragm 71, and the other end is supported by the tip of the adjusting screw 73. The inside of the concave portion of the case 72 communicates with the atmosphere through the communication hole 72b, and therefore the adjusting screw 73 side of the diaphragm 71 is at atmospheric pressure.

For example, when the engine is driven and the high-temperature return fuel is returned into the main tank 1, the fuel vapor in the main tank 1 expands and the space MS in the main tank 1 expands.
, The main tank 1 may be deformed. At this time, since the reference tank 2 is in communication with the main tank 1 through the communication hole 2a, the space R in the reference tank 2
The pressure of S also increases. When the pressure in the space RS in the reference tank 2 increases in this way, the diaphragm 71 deforms toward the adjustment screw 73, and conversely, the space MS in the main tank 1
When the pressure in the reference tank 2 and the pressure in the space RS in the reference tank 2 decrease, the diaphragm 71 deforms toward the space RS. As a result, the volume in the reference tank 2 changes according to the pressure change in the reference tank 2 due to the expansion and contraction of the gas in the main tank 1 that causes the deformation of the main tank 1. Therefore, by adjusting the amount of change of the diaphragm 71 by the adjusting screw 73, the volume in the reference tank 2 changes according to the rate of change of the volume due to the deformation of the main tank 1 due to the expansion and contraction of the gas in the main tank 1. Can be adjusted to Also, when the fuel in the main tank 1 is sucked into the engine, the space in the main tank 1 becomes negative pressure and the main tank 1 may be deformed.
The volume change in this case is also adjusted by the diaphragm 71 in the same manner as described above.

At the open end of the reference tank 2, a pressure sensor 10 which constitutes a first pressure fluctuation detecting means of the present invention and is exposed to the space MS in the main tank 1 and detects a pressure fluctuation in the space MS is provided. It is installed. Further, a pressure sensor 20 that constitutes a second pressure fluctuation detecting unit of the present invention and detects a pressure fluctuation in the space RS in the reference tank 2 is supported in the reference tank 2. Thus, these pressure sensors 10, 20
To each space M of the main tank 1 and the reference tank 2
A detection signal corresponding to the pressure fluctuation value of S and RS is output to the controller 50. The pressure sensors 10 and 20 convert a pressure signal into an electric signal, and have various modes such as a microphone.

The controller 50 has a circuit configuration shown in the upper part of FIG. 2, and includes band-pass filters 11, 21 connected to the pressure sensors 10, 20, an A / D converter 12,
22 and a CPU (Central Processing Unit) 51, ROM
52 and a memory of a RAM 53, a timer 54, an input / output interface 55, and the like. The drive unit 40 is connected to the input / output interface 55, and the drive unit 40 is connected to the movable coil 32 of the actuator 30. . Further, a display device 60 is connected to the input / output interface 55. As the display device 60,
For example, there are various modes such as an analog display or a digital display fuel gauge.

The driving device 40 is, for example, an oscillator (not shown)
And a sine wave output signal of a predetermined frequency (for example, about 10 Hz) is supplied to the movable coil 32 of the actuator 30 in accordance with the output signal of the input / output interface 55. That is, the drive of the actuator 30 is controlled so as to cause a gas volume change of, for example, | v ₀ sinω ₀ t | in the main tank 1 and the reference tank 2. Here, v ₀ is the maximum value of the gas volume change caused by the compression / decompression wave output from the diaphragm 31.

The detection signals of the above-described pressure sensors 10 and 20 are supplied to band-pass filters 11 and 21, where the signal component of the angular frequency ω ₀ is extracted, and the A / D converter 1
It is converted into a digital quantity via the input / output interface 2 and 22 and supplied to the input / output interface 55.

In the controller 50, input / output processing, storage, and calculation are performed according to the detection signals of the pressure sensors 10 and 20, and the actuator 30 is driven, and the calculation result is output to the display device 60. You. That is,
The actuator 30 is driven according to a program executed by the CPU 51, and the volume of the space in the main tank 1 is determined.
Eventually, a series of arithmetic processing for obtaining the remaining fuel amount in the main tank 1 is performed, and the display device 60 displays the remaining fuel amount. This program includes, for example, a routine shown in FIG. 3 and is executed after an ignition switch (not shown) is turned on, and is processed as follows.

First, in step 101, the CPU 51
Are initialized, various operation values are cleared, and the timer is reset. Subsequently, in step 102, a function F used in step 107 described later is set as, for example, a predetermined linear function. Then, in step 103, the actuator 30 is driven according to the output from the driving device 40, the vibration plate 31 starts to vibrate, and the compression / decompression pressure wave is generated in the space MS in the main tank 1 and the space RS in the reference tank 2.
Is output to As a result, substantially the same pressure fluctuations (but opposite phases) occur in the respective spaces MS and RS under substantially the same conditions.

The pressure fluctuation in the spaces MS, RS is the pressure
The amount of change is detected by the force sensors 10 and 20, and
Pressure fluctuation value ΔP in the in-tank 1 and the reference tank 2_M,
ΔP_RIs required. The latter ΔP_RIs like
Can be represented by the former ΔP _MShould be expressed as in Equation 2.
Can be.

(Equation 1)

(Equation 2) However, gamma is the specific heat ratio of the gas in the main tank 1 and the reference tank 2, P ₀ is the absolute pressure in the main tank 1 and the reference tank 2, V _R is the volume of the space RS in the reference tank 2, V _M
In the volume of the space MS in the main tank 1, [Delta] V _A represents the volume variation amount of space MS due to deformation of the main tank 1 due to the driving of the actuator 30.

Proceeding to step 104, the pressure sensor 10,
20 are converted into digital quantities through band-pass filters 11 and 21 and A / D converters 12 and 22,
3 is stored. In step 105, the absolute values of the pressure fluctuation values ΔP _M and ΔP _R are determined for a predetermined time (for example, 30
S) are integrated and set as ΔP _AM and ΔP _AR , respectively, in the RAM 53.
Is stored in Then, the process proceeds to step 106, where the ratio λ (= the pressure fluctuation value ΔP _AR , ΔP _AM)
ΔP _AR / ΔP _AM ) is calculated. This ratio lambda, the sum of the volume and the volumetric change [Delta] V _A space MS in the main tank 1 V
The ratio of the volume V _R of the spatial RS of _M and the reference tank 2 (= (V
_M + ΔV _A ) / V _R ).

Then, the process proceeds to a step 107, wherein a liquid amount _VL of the fuel in the main tank 1 is calculated according to the value of the ratio λ. That is, the fuel amount _VL in the main tank 1 is calculated based on the function F set in step 102 described above. As the function F, for example, a linear function shown in Expression 3 is used.

(Equation 3) However, V _A is the main tank 1 volume (total volume), K ₀ is a constant. The constants K ₀ and ΔV _A are set by actually measuring the ratio λ of the pressure fluctuation value at the predetermined liquid volume V _L0 .

In step 108, the liquid volume V _L
Is supplied to the display device 60, and after a predetermined display is performed, the process returns to step 104, and the above operation is repeated, and the display is updated at a predetermined cycle. As it is subjected to may be configured to display the volume V _M space MS in the main tank 1, or directly other control device the output signal of the output interface 55 without providing the display device 60 or the like Is also good.

FIG. 5 shows another embodiment of the adjusting device. In place of the diaphragm 71, an elastic metal plate 76 is joined to the flange portion 2f via the gasket 3b, and is fixed by an annular retainer 75. . Thus, also in the present embodiment, the elastic metal plate 76 is deformed according to the change in the pressure in the reference tank 2 due to the expansion and contraction of the gas in the main tank 1 which causes the deformation of the main tank 1, and The volume in 2 changes.

In the above-described embodiment, control by digital processing is mainly performed, but it is needless to say that all processing can be performed by analog processing. Further, in this embodiment, the liquid amount measuring device for measuring the remaining fuel amount is used. However, the liquid amount measuring device is not limited to the fuel, and may be a device for measuring the accommodation amount of powder, granules, deformed objects, and the like.

[0027]

The present invention has the following effects because it is configured as described above. That is, according to the volume measuring method of the present invention, the volume in the reference tank is adjusted by adjusting the volume in the reference tank so as to be substantially equal to the volume change rate due to the deformation of the main tank accompanying the expansion and contraction of the gas in the main tank. , The measurement error caused by the deformation of the main tank due to the expansion and contraction of the gas in the main tank can be suppressed, and good measurement accuracy can be secured.

Further, in the volume measuring device of the present invention,
Equipped with adjusting means to control the expansion and contraction of gas in the main tank
Since the volume in the reference tank is adjusted to be approximately equal to the rate of volume change due to the deformation of the main tank, the measurement error caused by the deformation of the main tank caused by the expansion and contraction of the gas in the main tank can be reduced with a simple configuration. It can be suppressed, and good measurement accuracy can be secured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of a volume measuring device of the present invention.

FIG. 2 is a block diagram showing a configuration of a volume measuring device according to one embodiment of the present invention.

FIG. 3 is a flowchart showing processing by a controller according to an embodiment of the present invention.

FIG. 4 is a sectional view showing one embodiment of an adjusting device in the volume measuring device of the present invention.

FIG. 5 is a sectional view showing another embodiment of the adjusting device in the volume measuring device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main tank 2 Reference tank 2a Communication hole 10, 20 Pressure sensor 30 Actuator 31 Vibration plate 32 Moving coil 40 Drive device 50 Controller 60 Output device 70 Adjustment device 71 Diaphragm

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Masatomi Takaesu 2-26 Konosu-cho, Toyota City, Aichi Prefecture Inside Horie Metal Industry Co., Ltd. (56) References JP-A-3-118443 (JP, A) Hei 4-47231 (JP, A) JP-A-2-19717 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01F 17/00 G01F 22/02

Claims (2)

(57) [Claims] 1. A main tank having a predetermined shape for storing a fluid, a reference tank communicating with the main tank, a space in the reference tank and a space above the fluid in the main tank, each having a different volume. And an actuator that applies pressure fluctuation to the main tank and the reference tank to detect the operating state pressure fluctuation value of each of the main tank and the reference tank, and based on a ratio of the respective operating state pressure fluctuation values, In a volume measuring method for calculating a volume of a space in a main tank, expansion of gas in the main tank is performed.
A volume measuring method, wherein a volume of the space in the main tank is calculated by adjusting a volume in the reference tank so as to be substantially equal to a volume change rate due to deformation of the main tank due to shrinkage . 2. A main tank having a predetermined shape for storing a fluid, a reference tank communicating with the main tank, a space in the reference tank and a space in the main tank above the fluid, each having a different volume. An actuator for applying pressure fluctuation, a driving means for driving the actuator, and a volume change rate in the reference tank so as to be substantially equal to a volume change rate due to deformation of the main tank accompanying expansion and contraction of gas in the main tank. Adjusting means for adjusting the volume; first pressure fluctuation detecting means for detecting a pressure fluctuation value in a space above the fluid in the main tank; and second detecting means for detecting a pressure fluctuation value in a space in the reference tank. A pressure fluctuation detecting unit, the main tank and the main tank detected by the first and second pressure fluctuation detecting units in a state where the actuator is operated; Calculating means for calculating the volume of the space in the main tank based on the ratio of the operating state pressure fluctuation values of the reference tank.