JPH06273213A - Volume measuring method and volume measuring device - Google Patents

Abstract

PURPOSE:To suppress the measurement error due to deformation of a main tank according to expansion/contraction of a gas inside the main tank and to secure excellent measurement precision in a measuring method and device, by which the volume of the main tank is measured on the basis of a pressure fluctuation values inside both spaces of the main tank and 8 reference tank. CONSTITUTION:The volume of a reference tank ST is controlled to be approximately equal to a rate of change due to deformation of a main tank by a controlling means BT. An actuator AT varies each of volumes of a space inside the reference tank and a space of upper side of a fluid inside the main tank MT so as to apply pressure fluctuation to each of them. While the actuator is actuated, the first pressure fluctuation detecting means M1 and the second pressure fluctuation detecting means M2 detect actuating condition pressure fluctuation values of the main tank and the reference tank individually, and a computing means M4 computes the volume of the main tank on the basis of the rate between the actuating condition pressure fluctuation values of respective tanks.

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 apparatus, and more particularly to a main tank having a predetermined shape for accommodating a fluid, which is provided in communication with a reference tank having a small volume so that the volume of the space in both tanks can be controlled. The present invention relates to a volume measuring method and a volume measuring apparatus which change 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 apparatus for measuring the volume of liquid, powder, etc. contained in a tank,
Various methods and apparatuses have been proposed as described in JP-A-2-19717. For example, in the embodiment shown in FIG. 10 of the publication, the main tank 30 and the correction tank 31 are completely closed, and both tanks are connected by a thin pipe 47 to equalize the static pressure. There is. Then, with respect to the main tank 30 and the correction tank 31, the volume change mechanism 33 changes the volume in each tank 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, description thereof will be omitted. However, the volume of the space in the main tank 30 (that is, the total volume of the main tank if there is no content in the main tank, the content is If present, the volume other than the contents in the main tank is the main tank 30.
Further, it is disclosed that the calculation can be performed according to the detection output of the pressure fluctuation in the correction tank 31.

[0003]

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

However, according to the method and apparatus described in the above publication, the deformation of the main tank is treated 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 is caused. The change in volume due to the accompanying deformation of the main tank is not taken into consideration, and errors may still occur. Although the term “correction tank” is used in the above publication, in the present application,
Considering the function of giving pressure fluctuations that should be referred to when measuring the volume of the space in the main tank, the reference tank is used.

Therefore, the present invention provides a volume measuring method and a volume measuring apparatus for changing the volumes of the spaces 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. It is an object of the present invention to suppress errors caused by deformation of the main tank due to expansion and contraction of gas in the main tank, and to secure 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, and 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 the volume measuring method for detecting and calculating the volume of the space in the main tank based on the ratio of the respective operating state pressure fluctuation values, in the reference tank so as to be approximately equal to the volume change rate due to the deformation of the main tank. Is adjusted to calculate the volume of the space in the main tank.

The volume measuring apparatus of the present invention has a main tank MT having a predetermined shape for containing a fluid, a reference tank ST communicating with the main tank MT, and a reference tank ST, as shown in the outline of the configuration in FIG. Inner space and main tank M
The actuator AT for changing the volume of each of the spaces above the fluid in T to apply pressure fluctuations, the drive means M3 for driving the actuator AT, and the volume change rate due to the deformation of the main tank MT are approximately equal to each other. Adjusting means BT for adjusting the volume in the reference tank ST, first pressure fluctuation detecting means M1 for detecting the pressure fluctuation value in the space above the fluid in the main tank MT, and pressure fluctuation value in the space in the reference tank ST. Of the main tank MT and the reference tank ST detected by the first and second pressure fluctuation detecting means M1 and M2 while the actuator AT is operating. The calculation means M4 for calculating the volume of the space in the main tank MT based on the ratio of the values is provided.

[0008]

In the above volume measuring method, the operating state pressure fluctuation values of the main tank and the reference tank are detected while the actuator is operating. Then, the ratio of each operating state pressure fluctuation value 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 temperature change, and the main tank may be deformed accordingly, but the volume in the reference tank communicating with the main tank is changed by the deformation of the main tank. It is 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 apparatus constructed as shown in FIG. 1, when the actuator AT is driven by the driving means M3, 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 may expand and contract due to a temperature change, for example, and the main tank MT may be deformed accordingly. However, the reference tank S communicating with the main tank MT may
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 offset. Thus, while the actuator AT is operating, the operating state pressure variation values of the main tank MT and the reference tank ST are detected by the first and second pressure variation detecting means M1 and M2. Then, the ratio of the operating state pressure fluctuation values is calculated in 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 device of the present invention and are applied to a liquid amount measuring device for measuring the amount of fuel remaining in a fuel tank of an automobile. The fuel tank has a main tank 1 that defines a closed space, and when the space MS formed above when fuel is injected is minimum, that is, the liquid level F
The opening 1a is formed at a position communicating with the space MS even when L reaches the maximum. A cylindrical reference tank 2 is accommodated in this opening 1a, a flange portion 2f formed at one end thereof is pressed against the opening 1a via a gasket 3a, and further, a flange portion 2f is inserted through a gasket 3b. The cover 4 is pressed. In addition, the adjusting device 70 described later
The case 72 is joined to the cover 4. These case 72, cover 4, flange 2f, and gasket 3
The a and 3b are fixed to the main tank 1 by an annular retainer 1b fixed to the main tank 1 and a bolt (not shown) screwed to the retainer 1b. It should be noted that the reference tank 2 is arranged not to be housed in the main tank 1 but to be joined so that only the front end portion of the reference tank 2 is joined to the opening 1 a and the remaining portion projects outward from the main tank 1. Good.

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

When an AC voltage drive signal is supplied to the movable coil 32, the vibrating plate 31 vibrates, and the space MS in the main tank 1 and the space RS in the reference tank 2 are reversed at the same time. A phase compressional pressure wave is output. It should be noted that the actuator 30 is not limited to the above, but a coil is wound around a core connected to a permanent magnet, and an electromagnetic type device that vibrates the diaphragm 31 by supplying a drive signal to the coil is configured. Good. In addition, various configurations such as an electrostatic type, an electrostrictive type, and a magnetostrictive type used in the field of speakers 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 which is an adjusting means according to the present invention. That is, as shown in the enlarged view of FIG. 4, a circular through hole 4a is formed in the central portion of the cover 4.
And a diaphragm 71 is provided so as to cover the same, and the periphery thereof is sandwiched between the flange portion 72a of the case 72 and the cover 4. A recess is formed in the center of the case 72, and an adjusting screw 73 is screwed to the bottom of the recess. 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 recess of the case 72 communicates with the atmosphere through the communication hole 72b, and therefore the pressure on the adjusting screw 73 side of the diaphragm 71 is atmospheric pressure.

For example, when the engine is driven and high-temperature return fuel is returned to the main tank 1, the fuel vapor in the main tank 1 expands and the space MS in the main tank 1
There is a case that the pressure rises and the main tank 1 is deformed. At this time, since the reference tank 2 communicates with the main tank 1 through the communication hole 2a, the space R in the reference tank 2
The pressure of S also becomes large. When the pressure in the space RS in the reference tank 2 increases in this way, the diaphragm 71 deforms toward the adjusting screw 73 side, and conversely, the space MS in the main tank 1
When the pressure of, and consequently the pressure of the space RS in the reference tank 2 decreases, 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 caused by the expansion and contraction of the gas in the main tank 1 which causes the deformation of the main tank 1. Therefore, by adjusting the amount of change in the diaphragm 71 with the adjusting screw 73, the volume in the reference tank 2 changes according to the rate of change in 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 Further, even 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 above.

At the opening end of the reference tank 2, there is provided a pressure sensor 10 which constitutes the first pressure fluctuation detecting means of the present invention and is exposed to the space MS in the main tank 1 to detect the pressure fluctuation in the space MS. It is installed. Further, a pressure sensor 20 which constitutes a second pressure fluctuation detecting means of the present invention and detects a pressure fluctuation of the space RS in the reference tank 2 is supported in the reference tank 2. Thus, these pressure sensors 10, 20
To the space M of each of the main tank 1 and the reference tank 2
A detection signal corresponding to the pressure fluctuation values 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 the circuit configuration shown in the upper part of FIG.
22, CPU (Central Processing Unit) 51, ROM
Each of the memory 52 and the RAM 53, a timer 54, an input / output interface 55, and the like are built in. The drive device 40 is connected to the input / output interface 55, and the drive device 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) according to the output signal of the input / output interface 55 is supplied to the movable coil 32 of the actuator 30. 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. In addition, v ₀ is the maximum value of the gas volume change caused by the dense and dense pressure waves output from the diaphragm 31.

The detection signals of the pressure sensors 10 and 20 described above are supplied to bandpass filters 11 and 21, where the signal component of the angular frequency ω ₀ is extracted and the A / D converter 1 is used.
It is converted to a digital amount via 2, 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, the actuator 30 is driven, and the calculation result is output to the display device 60. It 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
As a result, a series of arithmetic processing for obtaining the remaining fuel amount in the main tank 1 is performed, and the remaining fuel amount is displayed on the display device 60. This program is composed of, for example, the routine shown in FIG. 3, is executed after the ignition switch (not shown) is turned on, and is processed as follows.

First, in step 101, the CPU 51
Are initialized, various calculated values are cleared, and the timer is reset. Then, in step 102, the 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 drive device 40, the vibration plate 31 starts to vibrate, and the compression-dense pressure wave causes 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 fluctuations in the spaces MS and RS are
The amount of change detected by the force sensors 10 and 20 is measured.
Pressure fluctuation value ΔP in the in-tank 1 and the reference tank 2_M，
ΔP_RIs required as. The latter ΔP_RLike the number 1
Can be represented, the former ΔP _MShould be expressed as
You can

[Equation 1]

[Equation 2] Where γ 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
Is the volume of the space MS in the main tank 1, and ΔV _A is the volume change amount of the space MS due to the deformation of the main tank 1 due to the driving of the actuator 30.

Proceeding to step 104, the pressure sensor 10,
The detection signal of 20 is converted into a digital amount through the band pass filters 11 and 21 and the A / D converters 12 and 22, and the RAM 5 is passed through the input / output interface 55.
3 is stored. Then, in step 105, the absolute values of the pressure fluctuation values ΔP _M and ΔP _R are set for a predetermined time (for example, 30
Second) are integrated and set as ΔP _AM and ΔP _{AR respectively,} and RAM 53
Stored in. Further proceeding to step 106, the ratio λ (= of the pressure fluctuation values ΔP _AR , ΔP _AM obtained as described above
ΔP _AR / ΔP _AM ) is calculated. This ratio λ is the sum V of the volume of the space MS in the main tank 1 and the volume change amount ΔV _A.
The ratio of _M to the volume V _R of the space RS in the reference tank 2 (= (V
_M + ΔV _A ) / V _R ).

Then, the routine proceeds to step 107, where the liquid quantity V _L of the fuel in the main tank 1 is calculated according to the value of the ratio λ. That is, the liquid amount _VL of the fuel 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 capacity (total volume) of the main tank 1, and K ₀ is a constant. The constants K ₀ and ΔV _A are set by actually measuring the ratio λ of pressure fluctuation values at a predetermined liquid amount V _L0 .

Then, in step 108, the above-mentioned liquid amount 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. The volume V _M of the space MS in the main tank 1 may be displayed, or the output signal of the input / output interface 55 may be directly provided to another control device or the like without providing the display device 60. Good.

FIG. 5 shows another embodiment of the adjusting device. Instead 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 this 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 reference tank is deformed. The volume in 2 changes.

In the above-mentioned embodiment, the control by digital processing was mainly performed, but of course, all can be processed by analog processing. Further, although the liquid amount measuring device for measuring the remaining amount of fuel is used in the present embodiment, the device for measuring the contained amount of powder, granules, deformed objects, etc. is not limited to fuel.

[0027]

Since the present invention is configured as described above, it has the following effects. That is, according to the volume measuring method of the present invention, 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. It is possible to suppress a measurement error caused by the deformation of the main tank due to the expansion and contraction of the gas in the main tank, and to secure good measurement accuracy.

Further, in the volume measuring apparatus of the present invention,
Since the volume in the reference tank is adjusted so as to be approximately equal to the volume change rate due to the deformation of the main tank, it is possible to suppress the measurement error due to the deformation of the main tank with a simple configuration. Good measurement accuracy can be secured.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration of a volume measuring apparatus according to an 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 an 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]

 1 Main Tank 2 Reference Tank 2a Communication Holes 10, 20 Pressure Sensor 30 Actuator 31 Vibration Plate 32 Moving Coil 40 Drive Device 50 Controller 60 Output Device 70 Adjusting Device 71 Diaphragm

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masatomi Takasu 2-26, Kounosu-cho, Toyota-shi, Aichi Horie Metal Industry Co., Ltd.

Claims (2)

[Claims] 1. 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 and a space above the fluid in the main tank, each of which has a different volume. An actuator for applying a pressure fluctuation by driving the actuator to detect an operating state pressure fluctuation value of each of the main tank and the reference tank, and based on a ratio of each operating state pressure fluctuation value, In a volume measuring method for calculating the volume of the space in the main tank, the volume of the space in the main tank is calculated by adjusting the volume in the reference tank so as to be approximately equal to the rate of change in volume due to deformation of the main tank. A method for measuring volume, comprising: 2. 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 and a space above the fluid in the main tank, each volume is changed. An actuator for applying a pressure fluctuation, a driving means for driving the actuator, an adjusting means for adjusting the volume in the reference tank to be substantially equal to a volume change rate due to the deformation of the main tank, and the main tank First pressure fluctuation detecting means for detecting a pressure fluctuation value in a space above the fluid in
Second pressure fluctuation detecting means for detecting a pressure fluctuation value in the space inside the reference tank, and the main tank and the reference tank detected by the first and second pressure fluctuation detecting means while the actuator is operating. And a calculation means for calculating the volume of the space in the main tank based on the ratio of the respective operating state pressure fluctuation values.