JPH06300608A - Residual quantity of fuel measuring equipment - Google Patents

Abstract

PURPOSE:To provide a residual fuel measuring equipment for measuring the residual fuel in a main tank based on the ratio of pressure variation values in main and reference tanks in which accuracy is ensured stably in the measurement by suppressing the measurement error due to communication with a fuel vapor gas discharge suppressor. CONSTITUTION:Fuel vapor gas produced in a main tank MT is absorbed by a fuel vapor gas discharge suppressor M6 through a valve V under open state. When the residual fuel is measured, a control means M5 drives the valve V to close and a drive means M3 drives an actuator AT to cause pressure variation in the spaces of a reference tank ST and the main tank MT. Under that state, first and second pressure variation detecting means M1, M2 detect the pressure variation values of the tanks MT, ST under operating state and an operating means M4 operates the ratio thereof thus determining the residual quantity of fuel in the main tank MT.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel residual amount measuring apparatus, and more particularly, to a main tank of a predetermined shape for accommodating fuel, which is provided with a small-capacity reference tank in communication with each other to change the volume of the space in both tanks. The present invention relates to a fuel remaining amount measuring device for measuring the fuel remaining amount in the main tank based on the 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 same publication, for the main tank 30 and the correction tank 31, the volume in each tank is changed by the volume changing mechanism 33 to cause pressure fluctuation, and the second amplitude detector Three
The output γ · P ₀ · v ₀ from 9a is fed to the first amplitude detector 39
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 b. 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.

By the way, in a fuel supply system of an automobile, fuel in a fuel tank is supplied to an engine by a fuel pump, and surplus fuel is returned to the fuel tank through a return tube. When this fuel is, for example, highly volatile gasoline, gasoline vapor, that is, fuel evaporative emission gas is generated in the fuel tank. In order to prevent the pressure in the fuel tank from rising due to the fuel evaporative gas, and to prevent the fuel evaporative gas from being released into the atmosphere, a fuel evaporative gas emission suppression device is mounted.
For example, direct the fuel vapor to the charcoal canister,
A device is known in which charcoal, that is, activated carbon is once adsorbed, air is introduced into the charcoal canister by negative intake pressure during engine operation, and the fuel components adsorbed by activated carbon are sent to the intake system to restore the adsorption capacity of activated carbon. ,
For example, it is described in US Pat. No. 3,884,204.

At the top of the canister, there is provided a first check valve that opens when the pressure in the fuel tank becomes equal to or higher than a first set pressure (for example, a positive pressure of a predetermined value), and the inside of the fuel tank A second check valve is provided that opens when the pressure becomes equal to or lower than a second set pressure (for example, a negative pressure of a predetermined value), and prevents the fuel tank from being deformed due to pressure rise or fall in the fuel tank. I have decided. A third check valve that opens when the intake system side falls below a third set pressure is also provided in the portion of the top of the canister that communicates with the intake system of the engine.

[0005]

In the above measuring apparatus, when the space above the fuel in the main tank communicates with the canister in response to the operation of the check valve provided in the canister, the pressure fluctuation in the main tank due to the actuator is changed. And the pressure fluctuation in the correction tank change, causing a measurement error. FIG. 5 is an experimental example showing the situation during this period. When the internal pressure of the main tank rises as shown in the upper stage of FIG. 5 and the check valve opens about 3 minutes later, about 1 minute later, the lower stage of FIG. As shown in, a large measurement error will occur.

In view of the above, the present invention is directed to a fuel residual amount measuring device which changes the volumes of the spaces in the main tank and the reference tank and measures the fuel residual amount in the main tank based on the ratio of the pressure fluctuation values in both spaces. An object of the present invention is to suppress a measurement error caused by communication with the fuel evaporative emission control device and to secure stable measurement accuracy. Although the term “correction tank” is used in the above-mentioned publication, in the present application, the reference tank is used in view of the function of giving a pressure fluctuation to be referred to when measuring the volume of the space in the main tank.

[0007]

In order to achieve the above object, a fuel residual amount measuring apparatus of the present invention has a main tank MT of a predetermined shape for accommodating a fuel FD, as shown in the outline of the configuration in FIG. , A reference tank ST communicating with the main tank MT
An actuator AT for changing the volume of each of the space in the reference tank ST and the space above the fuel in the main tank MT to apply pressure fluctuations;
Driving means M3 for driving the first tank, first pressure fluctuation detecting means M1 for detecting a pressure fluctuation value in a space above the fuel in the main tank MT, and second pressure fluctuation detecting means M1 for detecting a pressure fluctuation value in a space in the reference tank ST. Based on the ratio of the operating state pressure fluctuation value of each of the main tank MT and the reference tank ST detected by the pressure fluctuation detecting means M2 and the first and second pressure fluctuation detecting means M1 and M2 while the actuator AT is operating, The calculating means M4 for calculating the remaining fuel amount in the tank MT is provided. Further, a fuel evaporative emission control device M6 for further absorbing the fuel evaporative emission in the main tank MT.
And an on-off valve V interposed in a communication passage that connects the fuel evaporative emission control device M6 and the main tank MT, drive means M3 and calculation means M4, and the amount of fuel remaining in the main tank MT. When calculating
And a control means M5 for controlling so as to close.

[0008]

In the fuel quantity measuring device configured as described above, if the on-off valve V is in the open state, the fuel evaporative emission gas generated in the main tank MT via this is the fuel evaporative emission control device M6. Is absorbed by. When measuring the fuel level,
After the on-off valve V is closed and driven by the control means M5, the drive means M3 and the calculation means M4 are driven. Drive means M
When the actuator AT is driven by 3, the pressure fluctuation is applied to the spaces in the reference tank ST and the main tank MT. With the actuator AT thus operating, the first and second pressure fluctuation detecting means M1, M2
Thus, the operating state pressure fluctuation value of each of the main tank MT and the reference tank ST is detected. And the calculation means M
In 4, the ratio of each operating state pressure fluctuation value is calculated,
The fuel remaining amount in the main tank MT is calculated based on this ratio. Thus, it is possible to suppress the measurement error that occurs when the space above the fuel in the main tank MT communicates with the fuel evaporative emission control device M6.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 2 to 4 show a fuel residual amount measuring device for measuring a fuel residual amount of an automobile fuel tank according to an embodiment of the present invention. The fuel tank has a main tank 1 that defines a closed space, and the overall structure is schematically shown in FIG. 2. A fuel injection pipe 6 is provided in the main tank 1, and a discharge port 6a is provided in the main tank. 1 is opened below, and the inlet 6b is attached so as to be located above the outside of the main tank 1. Further, a breather tube 7 that connects the vicinity of the injection port 6b of the fuel injection pipe 6 and the upper space MS in the main tank 1 is provided, and the liquid level of the fuel is regulated by the opening end 7a in the main tank 1. It is configured to be. Further, the injection port 6b of the fuel injection pipe 6
A cap 8 is provided on the discharge port 6a, and a check valve 9 is provided on the discharge port 6a. The check valve 9 is a high-pressure fuel when the cap 8 is removed with the internal pressure of the space MS above the fuel in the main tank 1 rising when the main tank 1 full of fuel is heated. To prevent backflow in the direction of the injection port 6b. A reference tank 2 described below is provided above the main tank 1, and a communication pipe 71 is connected.

That is, the space MS in the main tank 1 is communicatively connected to the canister 80 via a communication pipe 71, and the communication pipe 71 is provided with an opening / closing valve 70. The on-off valve 70 of the present embodiment is a normally open 2-port 2-position electromagnetic switching valve, which is normally open and is closed when the solenoid coil 70a is energized. The canister 80 constitutes the fuel evaporative emission control device according to the present invention, and a charcoal 80c which is an adsorbent for the fuel evaporative gas is housed in a cylindrical body, and a communication hole 80a communicating with the atmosphere is provided below. Are formed. The upper part of the tubular main body of the canister 80 is connected to the communication pipe 71 via the first and second check valves 81 and 82, and is connected to the communication pipe 72 via the third check valve 83.
The communication pipe 72 is communicatively connected to an intake system (not shown) of the engine.

The first check valve 81 opens when the pressure in the main tank 1 exceeds a predetermined value P1, and the second check valve 82.
Is set to open when the pressure in the main tank 1 becomes a predetermined value P2 or less, and the third check valve 83 is set to open when the intake system side of the engine becomes a predetermined value P3 or less. Then, when the fuel evaporative emission increases, the pressure in the main tank 1 rises. When the pressure in the main tank 1 becomes equal to or higher than the predetermined value P1, the first check valve 81 opens, so that the inside of the main tank 1 communicates with the canister 80, and the fuel evaporative gas is adsorbed by the charcoal 80c. The adsorbed fuel is sucked into the engine through the third check valve 83 and burns when the vehicle is traveling.

As shown in FIG. 3, when the space MS formed above when the 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. A case 5 shown by a broken line is joined to the cover 4, and a closed space is defined between the two. The case 5, the cover 4, the flange portion 2f, and the gaskets 3a and 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. 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 FIG. 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 3 is attached to the core 33.
2 is arranged so as to be movable in the axial direction of the reference tank 2. A communication hole 33 a is formed in the center of the core 33, and the cover 4 and the diaphragm 31 define a space RS in the reference tank 2. 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 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 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.

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 space surrounded by the case 5 and the cover 4 accommodates circuit elements and the like constituting the controller 50, and the pressure sensors 10 and 20 are connected to the controller 5 by the controller 5.
It is connected to 0.

The controller 50 includes the pressure sensors 10 and 2
Band pass filters 11, 21 and A respectively connected to 0
A / D converters 12 and 22, and further includes CPU (central processing unit) 51, ROM 52 and RAM 53,
The timer 54, the input / output interface 55, etc. are built in, and the drive unit 40 is connected to the input / output interface 55.
Is connected, and the drive device 40 is connected to the movable coil 32 of the actuator 30. A display device 60 is connected to the input / output interface 55. As the display device 60, there are various modes such as a fuel gauge of analog display or digital display. Further, the input / output interface 55 is connected to the solenoid coil 70 a of the opening / closing valve 70 via the drive circuit 41.

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 the bandpass filters 11 and 21, where the signal components of the angular frequency ω ₀ are extracted and converted into digital quantities via the A / D converters 12 and 22. It is supplied to the input / output interface 55.

In the controller 50, the opening / closing valve 70 is controlled to open / close and the actuator 30 is driven. In addition, input / output processing, storage, and calculation are performed according to the detection signals of the pressure sensors 10 and 20, and the calculation result is output to the display device 60. That is, the actuator 30 is driven according to the program executed by the CPU 51,
A series of calculation processes for determining the volume of the space in the main tank 1 and thus the remaining fuel amount in the main tank 1 are performed, and the remaining fuel amount is displayed on the display device 60. This program consists of, for example, the routine shown in FIG. 4, 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 108 described later is set. Then, in step 103, the on-off valve 70 is closed and the communication with the canister 80 is cut off. Then, in step 104, the actuator 30 is output according to the output from the drive device 40.
Is driven. That is, the vibrating plate 31 starts to vibrate, and the compression / dense pressure wave causes the space MS in the main tank 1 and the reference tank 2 to flow.
It is output to the internal space RS. As a result, each space M
Under substantially the same conditions for S and RS, substantially the same pressure fluctuations (however, opposite phases) occur.

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, ΔV _A
Indicates 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 105, 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 106, 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 107, 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 ratio of the sum of the volume V _M of the space MS in the main tank 1 and the volume change amount ΔV _A to the volume V _R of the space RS in the reference tank 2 (= (V
_M + ΔV _A ) / V _R ). And step 1
In step 08, the liquid amount (remaining fuel amount) V _L in the main tank 1 is calculated based on the following expression 3 according to the value of the ratio λ.

[Equation 3]However, V_AIs the capacity (total volume) of the main tank 1, K₀Is
It is a constant. The constant K ₀, ΔV_AIs the predetermined liquid volume V_L0To
It is set by actually measuring the ratio λ of pressure fluctuation values in
It

Then, in step 109, the above-mentioned liquid volume V _L
Is supplied to the display device 60 and a predetermined display is performed, and then at step 110, the actuator 3
0 is turned off and the opening / closing valve 70 is opened in step 111.
Is opened. Then, after the lapse of a predetermined time T ₀ (step 112), the process returns to step 103 and the above-described operation is repeated, so that the display is updated at a predetermined cycle (T ₀ ). The volume V _M of the space MS in the main tank 1
May be configured to display, or the display device 6
The output signal of the input / output interface 55 may be directly provided to another control device or the like without providing 0.

As described above, according to the present embodiment, the on-off valve 70 is closed while the remaining fuel amount is measured, so that the space MS in the main tank 1 can be caused by communicating with the canister 80. The measurement error can be surely suppressed. In the present embodiment, the control by digital processing was the main focus, but it goes without saying that all can be analog processing. Further, in the present embodiment, the canister is used as the fuel evaporative emission control device, but the present invention is not limited to this. For example, the space above the fuel in the main tank is directly connected to the intake system of the engine, An on-off valve may be provided in the passage.

[0024]

Since the present invention is configured as described above, it has the following effects. That is, in the fuel residual amount measuring device of the present invention, an opening / closing valve is provided in a communication passage that connects the fuel tank with the fuel evaporative emission control device for absorbing the fuel evaporative gas in the main tank. Since it is configured to close the on-off valve when calculating the remaining fuel amount, it is possible to suppress the measurement error that occurs when the space above the fuel in the main tank communicates with the fuel evaporative emission control device. It is possible to ensure stable measurement accuracy.

[Brief description of drawings]

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

FIG. 2 is a sectional view schematically showing the structure of a fuel tank and a fuel evaporative emission control device according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a fuel remaining amount measuring device according to an embodiment of the present invention.

FIG. 4 is a flowchart showing processing by a controller in an embodiment of the present invention.

FIG. 5 is a graph showing a situation of an internal pressure of a fuel tank and a measurement error when a check valve of a canister in a conventional device is opened.

[Explanation of symbols]

 1 Main Tank 2 Reference Tank 2a Communication Hole 6 Fuel Injection Pipe 7 Breather Tube 8 Cap 9 Check Valve 10, 20 Pressure Sensor 30 Actuator 31 Vibration Plate 32 Moving Coil 40 Drive Device 50 Controller 60 Output Device 70 Open / Close Valve 80 Canister 81, 82,83 Check valve

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

Claims (1)

[Claims] 1. A main tank having a predetermined shape for accommodating fuel, a reference tank communicating with the main tank, a space in the reference tank and a space above the fuel in the main tank, and each volume is changed. An actuator for applying a pressure fluctuation, a driving means for driving the actuator, a first pressure fluctuation detecting means for detecting a pressure fluctuation value in a space above the fuel in the main tank, and a reference tank in the reference tank. Second pressure fluctuation detecting means for detecting a pressure fluctuation value in the space, and operating states of each of the main tank and the reference tank detected by the first and second pressure fluctuation detecting means while the actuator is operating. A calculating means for calculating the remaining amount of fuel in the main tank based on the ratio of pressure fluctuation values, and a fuel for absorbing the fuel evaporative gas in the main tank. A material evaporative emission control device, an on-off valve interposed in a communication passage that connects the fuel evaporative emission control device to the main tank, drive control of the drive means and the computing means, and the inside of the main tank And a control means for controlling the opening / closing valve to be closed when the remaining fuel amount is calculated.