JPH01112117A - Detecting device for rest of liquid in tank - Google Patents

Abstract

PURPOSE:To accurately detect the rest of liquid in the tank even if the tank slants and the liquid surface waves by finding the air capacity in the tank and then finding the rest of the liquid in the tank from it. CONSTITUTION:Pressure P0 is measured by a pressure sensor 7, and then 1st and 2nd valves 5 and 6 are closed and a pump 4 is driven to raise the pressure in a pre-loading chamber 2 up to preset pressure P1. Then only the valve 6 is opened to adjust the pressure in the pre-loading chamber 2 to the same pressure P2 with the tank1. Here, when the air capacity of the tank 1 is denoted as V1, V1={(P1-P2)/(P2-P0)}XV according to Boyle-Charles' law method and the air capacity C1 in the tank 1 is found. Then the rest V3 of gasoline is found from V3=V0-V1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a device for detecting the leakage of liquid in a tank into which liquid has been injected. The present invention relates to a device for detecting the remaining amount of kerosene.

(Prior Art) Conventionally, as this type of remaining amount detection device, a float is generally floated in a tank and detection is performed based on the amount of vertical change in the liquid level.

However, with this float method, the float position tends to change easily when the car is stopped on a slope, or when the liquid level is undulating due to vibrations while driving, making it difficult to correctly remove the remaining liquid. Cannot be measured. In particular, it is inconvenient for car users that when the remaining amount is low, it is difficult to determine the exact amount remaining.

Another possibility is to measure the flow rate of fuel consumed through the fuel pipe and subtract it from the fuel injected into the tank to detect the remaining amount. It is inconvenient that the remaining amount cannot be displayed unless it is entered into the detection device in the form of a lubrication device, and even if the amount of refueling is input, if errors accumulate, an incorrect remaining amount will be displayed, which is inconvenient. may occur.

(Objective of the Invention) The present invention solves the above-mentioned problems, and is capable of accurately detecting the remaining amount of liquid in the tank without being affected by tank inclination, vibration, etc. The purpose is to provide a detection device.

(Structure of the Invention) The present invention provides a tank into which liquid is injected, a space connected to the tank via a passage, a pump that applies pressure to the space, and communication between the space and the atmosphere. A first valve that opens and closes, a second valve that is interposed in the passage and opens and closes communication between the tank and the space, a pressure sensor that detects the pressure in the space, and a pressure sensor that detects the remaining amount of liquid in the tank. A display device for displaying, driving of the pump and the first. Controls the opening and closing of the second valve, calculates the air volume in the tank from the detection signal of the pressure sensor 4 and the space volume, calculates the remaining amount of liquid in the tank from the tank volume and the above air volume, and displays it on the display. and a control section that outputs a display signal.

This configuration allows the pump to be driven and the first. By controlling the opening and closing of the second valve, the air volume in the tank is determined based on the detection signal of the pressure sensor and the volume of the space at that time, and the remaining amount of liquid in the tank is calculated from this air volume and the tank volume. is found.

(Embodiment) FIGS. 1 and 2 show a configuration in which the present invention is applied to a gasoline tank of a car. In these figures, 1 is the volume V
o gasoline tank (hereinafter referred to as tank), 2 a prepressure chamber as a space of volume IV2 connected to the tank 1 via a passage 3, 4 a pump that applies pressure in the prepressure chamber 2, and 5 a a first valve that opens and closes communication of the preload chamber 2 to the atmosphere;
6 is a second valve interposed in the passage 3 to open and close communication between the tank 1 and the preload v2; 7 is a pressure sensor that detects the pressure within the preload chamber 2; 8 is a fuel filler port; 10 is an outlet for supplying gasoline to the engine.

A control unit 20 controls the drive of the pump 4 and the opening and closing of the first and second valves 5.6, calculates the remaining amount of gasoline in the tank 1, and outputs a remaining amount display signal to the display 26. The control section 20 includes a microamplifier 1 for measuring the remaining amount.
- a differential amplifier 22 into which the detected value 8 of the pressure sensor 7 is input, and an A/D converter 2 which converts the output of this amplifier 22 into A/D and outputs it to the microcomputer 21;
3, the pump 4 is driven by the output signal of the microcomputer 21, and the first. It is comprised of a drive circuit 24 that opens and closes the second valve 5.6, and a display circuit 25 that drives a display 26 based on the output signal of the microcombination 1-21.

Next, the procedure for detecting the remaining amount using the above configuration will be explained with reference to the flowchart shown in FIG. The detection principle is tank 1
By measuring the air volume V1 in the tank, the tank volume ■
By subtracting Vl from 0, Ganrin residual ff1V
3 is required.

First, the volume Vo of the tank 1 and the volume 2 of the prepressure chamber 2 which are known in advance are stored in the memory of the microcombi 1-21 (step S1), and in the normal state, the first valve 5
, the second valve 6 is both opened and the pressure inside the tank 1 and the prepressure chamber 2 is brought to atmospheric pressure Pa (step 82
).

Next time you measure the remaining amount (YES in step S3)
, first measure the pressure with the pressure sensor 7 (step 84
). The measured value at this time is atmospheric pressure PO. After that, the first. The second valve 5.6 is closed (step S5), and the pump 4
(Step S6), and the pressure inside the prepressure chamber 2 is increased to a preset pressure P3 (Steps 87 to 8G).

At this time, the pressure inside the tank 1 remains at Po. Next, the pressure inside the prepressure chamber 2 is measured by the pressure sensor 7, and the detected value is set as Pl (step 510).

Next, in step 511), only the second valve 6 is closed, and the pressure in the prepressure chamber 2 and the tank 1 is made the same. The pressure at that time is measured by the pressure sensor 7 (step 512), and the value is
Set it to 2.

Here, if the air volume of tank 1 is vl, the above Pa
, Pl, P2, Vl, and V2, the following relational expression holds true according to Boyle-Charles' law.

Pa Vt +PI V2 =P2 (V1+V2
) Therefore, V1= ((Pt −P2 )/(P2−Po ))
V2, and the air volume v1 of tank 1 is found (step 5
13).

Therefore, the remaining amount of gasoline (3) can be calculated as follows: V3 = Vo - V+ (step 514). After displaying the remaining amount of gasoline on the display 26 based on the result of the calculation by the microcomputer 21, F-- returns to step S2.

Further, the determination in step S3 as to whether or not to perform the measurement may be made by measuring at regular intervals using a timer, or by operation from the driver's seat.

Strictly speaking, Boyle-Charles' law also includes a temperature term, so if temperature sensor 1 is installed in tank 1 and preload chamber 2, and temperature compensation is added using this detection signal, it will be even better. Detection accuracy can further be improved.

(Effects of the Invention) As described above, according to the present invention, since the air volume in the tank is determined and the remaining amount of liquid in the tank is determined from this, even if the tank is located at an angle, Further, even if the liquid level is undulating due to vibrations, the remaining amount can always be accurately detected without being influenced by such vibrations and without having cumulative errors. Particularly when there is only a small amount of gasoline remaining in the gasoline tank of a car, etc., being able to accurately display the remaining amount is advantageous because it allows the user to be accurately informed of the timing of refueling.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a device for detecting the appearance of liquid in a tank according to an embodiment of the present invention, FIG. 2 is a block diagram of a control section of the device, and FIG. 3 is a flowchart of the operation of the device. 1...Gasoline tank (tank), 2...Precompression chamber (
space), 3... passage, 4... pump, 5... first valve, 6... second valve, 7... pressure sensor, 20
...Control unit, 26...Display device. Patent applicant Matsushita Electric Works Co., Ltd. Agent
Patent Attorney Etsushi Kotani Patent Attorney Long 1) Masaru Patent Attorney Yasuo Itaya

Claims (1)

[Claims] 1. A tank into which liquid is injected, a space connected to the tank via a passage, a pump that applies pressure to the space, and a first valve that opens and closes communication between the space and the atmosphere.
a second valve interposed in the passageway to open and close communication between the tank and the space, a pressure sensor to detect the pressure in the space, and an indicator to display the remaining amount of liquid in the tank. , controls the drive of the pump and the opening/closing of the first and second valves, calculates the air volume in the tank from the detection signal of the pressure sensor and the space volume, and calculates the volume of liquid in the tank from the tank volume and the air volume. 1. A liquid remaining amount detection device in a tank, comprising: a control section that determines the remaining amount and outputs a display signal to a display device.