JPS6316979Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a residual liquid amount measuring circuit that electrically measures the remaining amount of fuel in, for example, an automobile.

As a conventional residual liquid amount measuring circuit, there is one shown in FIG. 1, for example. That is, the liquid level signal from the float type liquid level sensor 1 is taken into the A/D converter (analog/digital converter) 3 in time series, and its output is sequentially sent to the display 5 via the display control circuit 4. shall be supplied and displayed. In addition,
2 is a resistor for generating a voltage in accordance with the liquid level at the non-grounded terminal of the liquid level sensor 1, and 6 is a power supply circuit.

However, in such a conventional residual liquid amount measuring circuit, the liquid level sensor has a float,
In addition, since a sliding resistor is provided whose contacts move in conjunction with the vertical movement of the float and whose resistance value changes, the liquid level sensor is activated by the frictional force caused by the movement of the contacts of the sliding resistor. Hysteresis occurs in the sliding resistor part, and after the vehicle starts running, vibration is transmitted to the contact and the hysteresis is canceled and there is no problem. Although there is no problem as the hysteresis is absorbed into the display error,
When displaying at a pitch equal to or smaller than the hysteresis, the displayed value of the remaining liquid amount that changes depending on the amount of replenishment when refilling fuel etc. is due to the effect of hysteresis that occurs in the sliding resistor when the float rises. There was a problem where the amount displayed was less than the sum of the previous display amount and supply amount.

This idea was created by focusing on these conventional problems, and when replenishment of fuel, etc. is permitted, the hysteresis from the float type liquid level sensor is added to the liquid level signal and the remaining amount is calculated. The purpose is to solve the above problems by making the amount of liquid.

This invention will be explained below based on the drawings.

FIG. 2 is a diagram showing an embodiment of this invention. In FIG. 2, the same components as those in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted. Reference numeral 7 denotes a refueling end detection circuit which detects the end of refueling based on a change in the state of the fuel lid from an open state to a closed state, and outputs a refueling end detection signal when detected. 8
is a timer, and when a refueling end detection signal is supplied from the refueling end detection circuit 7, the output is set to the "H" level for a predetermined time. Reference numeral 9 denotes an adder circuit which adds a liquid amount corresponding to the hysteresis of the liquid level sensor 1 as a predetermined error to the liquid level signal supplied from the A/D converter 3, and outputs the corrected signal. 10 is a switching section, which has one movable contact 10a and two fixed contacts 10b and 10c.
When an "L" level signal is supplied from the timer 8, the contacts 10a and 10b are closed, and the A/D
The liquid level signal from the converter 3 is supplied to the display control circuit 4. Further, when an "H" level signal is supplied from the timer 8, the contacts 10a and 10c are closed,
The corrected liquid level signal output from the adder circuit 9 is supplied to the display control circuit 4. Note that the timer time of the timer 8 is set to a time sufficient for vibrations to eliminate hysteresis of the liquid level sensor 1 to be transmitted to the liquid level sensor 1 due to engine startup or running of the vehicle, for example. There is.

Next, the effect will be explained. When refueling is completed and the fuel lid is closed, and power supply from the power supply circuit 6 to various parts is started by an operation accompanying the start of the vehicle engine, the refueling end detection circuit 7 supplies a refueling end signal to the timer 8. , sets the output of timer 8 to "H" level. Thereby, the timer 8 is switched to the switching section 10.
The adder circuit 9 is closed between the contacts 10a and 10c.
displays the corrected liquid level signal by adding a predetermined error corresponding to the hysteresis of the liquid level sensor 1 to the liquid level signal supplied from the liquid level sensor 1 via the display control circuit 4. The liquid is supplied to the container 5 and displayed. Thereafter, vibrations are transmitted to the liquid level sensor 1 due to the running, and when the hysteresis is eliminated, the timer 8 ends the timer time and sets the output to the "L" level. Then, the switching unit 10 will be connected to the contacts 10a, 10.
Contacts 10a and 10b are closed instead of closing between C and C, and the liquid level signal from A/D converter 3 is displayed as it is on display 5 via display control circuit 4.

In the above embodiment, the timer 8 is used to ensure that the error is added until the hysteresis is canceled, but a new running detection circuit is provided without using the timer 8, and the running detection circuit is The outputs of the and refueling end detection circuit 7 are supplied to the AND gate, and the AND output is supplied to the switching unit 10, and only when refueling is completed and traveling has started, the connection between contacts 10a and 10b of the switching unit 10 is made. It may be closed.

FIG. 3 shows another embodiment. In FIG. 3, components having the same configuration as those in FIGS. 1 and 2 are given the same reference numerals, and their explanations will be omitted. Reference numeral 11 denotes an averaging circuit which inputs the liquid level signal supplied from the switching section 10 as data, averages a predetermined number of the data, and supplies an average value signal to the display control circuit 4.
Further, when the power supply from the power supply circuit 6 is stopped, the averaging circuit 11 is supplied with power from the memory retention power supply circuit 12 and stores the input liquid level signal. 13
A constant voltage detection circuit detects that the voltage supplied from the power supply circuit 6 is a predetermined voltage and outputs a comparison start signal to the comparison circuit 14. Comparison circuit 14
receives a comparison start signal from the constant voltage detection circuit 13, compares the liquid level signal from the A/D converter 3 and the average value signal from the averaging circuit 11, and determines that the difference is greater than a predetermined value, e.g. When it becomes 5 or more, a set signal of "H" level is outputted, and the averaging circuit 11
Outputs a discard signal to discard the liquid level signal stored in the . Reference numeral 15 denotes a running detection circuit, which outputs an "H" level reset signal when detecting running of the vehicle. Reference numeral 16 denotes an RS flip-flop which, when supplied with a set signal from the comparator circuit 14, outputs an "H" level, supplies this "H" level signal to the switching section 10, and closes the contacts 10a and 10c. Further, when the RS flip-flop 16 is supplied with a reset signal from the running detection circuit 15, the output is set to the "L" level, and the contacts 10a of the switching section 10,
10b is closed.

Next, the operation of the above configuration will be explained. When refueling is completed and power supply to each part is started from the power supply circuit 6 by operation associated with starting the engine of the vehicle,
Liquid level signal from A/D converter 3 and averaging circuit 1
1 is supplied to the comparison circuit 14, and at this time, in the constant voltage detection circuit 13, the output voltage of the power supply circuit 6 becomes a predetermined voltage, and the comparison circuit 1
When it is detected that the voltage has reached a level that prevents malfunction of circuits such as No. 4, a comparison start signal is supplied from the constant voltage detection circuit 13 to the comparison circuit 14, and the comparison is performed.
If the difference is smaller than a predetermined value, the liquid level signal from the A/D converter 3 is
It is supplied to the successive averaging circuit 11 via 0b.
In the averaging circuit 11, each time a liquid level signal is supplied, the liquid level signals are sequentially discarded in order of oldest and new average value is calculated, and the corresponding average value signal is sent to the display via the display control circuit 4. 5 is displayed. However, when the difference becomes more than a predetermined value, it is assumed that fuel has been supplied, and a set signal is supplied from the comparator circuit 14 to the RS flip-flop 16 to set its output to the "H" level, and the "H" level output to the switching unit 10. is supplied to close the contacts 10a and 10c instead of closing the contacts 10a and 10b.
Then, the liquid level signal from the A/D converter 3 is
In the adding circuit 9, a liquid amount corresponding to a predetermined error corresponding to the hysteresis of the liquid level sensor 1 is added and supplied to the averaging circuit 11. At this time, the averaging circuit 11
In this case, a discard signal is supplied from the comparator circuit 14 to discard the stored liquid level signal, and the averaging circuit 11 is sequentially supplied with the liquid level signal from the adder circuit 9 to calculate a new average value. be done. The newly calculated average value is supplied to the display 5 via the display control circuit 4 and displayed. When the vehicle starts running, the hysteresis of the liquid level sensor 1 is canceled by vibrations caused by the running of the vehicle, so a reset signal is supplied from the running detection circuit 15 to the RS flip-flop 16, and the RS flip-flop 1
6 is set to the "L" level, and the "L" level output is supplied to the switching unit 10, and the contacts 10a, 10
Instead of closing between contacts 10a and 10b, the liquid level signal from the A/D converter 3 is supplied to the averaging circuit 11.

As explained above, this invention is equipped with liquid level detecting parts 1, 2, and 3 driven by a float that responds to the liquid level in the tank, and the liquid level detecting part is In a remaining liquid amount measuring circuit that measures the amount of remaining liquid in a tank based on a signal, a replenishment detection section 7 that detects replenishment of liquid into the tank;
8, 11, and 14, and when replenishment of liquid is detected by the replenishment detection section, the liquid level signal from the liquid level detection section 1, 2, and 3 is The residual liquid amount measuring circuit is characterized by having adders 9 and 10 that add and output the hysteresis of the level detecting unit, so that the remaining liquid level measurement circuit is characterized by adding and outputting the hysteresis of the level detecting unit. Since the error in the amount of liquid is corrected, it is possible to accurately measure the amount of remaining liquid immediately after replenishment.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram showing the configuration of a conventional example, FIG. 2 is a circuit block diagram showing one embodiment of this invention, and FIG. 3 is a circuit block diagram showing another embodiment. 1...Liquid level sensor, 2...Resistance, 3...A/
D converter, 4...Display control circuit, 5...Display device,
6...Power supply circuit, 7...Refueling end detection circuit, 8...
...Timer, 9...Addition circuit, 10...Switching section, 1
1... Averaging circuit, 12... Memory retention power supply circuit,
13... Constant voltage detection circuit, 14... Comparison circuit, 1
5... Running detection circuit, 16... RS flip-flop.

Claims (1)

[Scope of utility model registration request] It is equipped with liquid level detection parts 1, 2, and 3 driven by a float that responds to the liquid level in the tank, and detects the amount of remaining liquid in the tank based on the liquid level signal from the liquid level detection part. In the remaining liquid amount measuring circuit, replenishment detection units 7, 8, 11, and 14 are provided to detect replenishment of liquid into the tank, and the replenishment detection unit detects replenishment of liquid. Adding units 9 and 10 are provided for adding the hysteresis of the liquid level detecting unit to the value of the liquid level signal from the liquid level detecting unit 1, 2, and 3 and outputting the result when the liquid level detecting unit 1, 2, and 3 A residual liquid amount measuring circuit featuring: