JPS5957119A - Fuel residual amount meter for vehicle - Google Patents

Abstract

PURPOSE:To enable the accurate display of a fuel residual amount as compared with a conventional method for judging a fuel supply time by the ON-OFF state of an ignition switch or a car speed signal, by judging the fuel supply time when the increment of a fuel residual amount signal exceeds a predetermined value. CONSTITUTION:The residual amount of fuel is detected by a fuel residual amount sensor 1 and the residual amount signal corresponding to the residual amount is sent to an averaging circuit 6 to perform averaging treatment. A subtraction circuit 7 performs the subtraction of the signal from the sensor 1 and the signal from the averaging circuit 6 to output a signal which is, in turn, sent to a comparator 8. The comparator 8 compares two signal levels by the signal from the subtraction circuit 7 and discriminates the increment of fuel to judge the supply of fuel. When the signal from the residual amount sensor 1 exceeds the signal from the averaging circuit 6, it is considered that fuel is increased and the supply of fuel is judged. A residual amount operation circuit 10 operates the residual amount of fuel corresponding to the signal from the averaging circuit 6 or the signal from the residual amount sensor 1 and the operated residual amount signal is sent to a display device 5 to be displayed. As a result, residual amount display can be accurately performed regardless of the ON-OFF state of an ignition switch.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel level meter for a vehicle that can accurately determine when to refuel when displaying the remaining fuel level by switching the responsiveness of the display between driving and refueling.

Conventionally, there have been known fuel level needles that measure and display the amount of fuel remaining in the fuel tank of a vehicle. There is a meter. In other words, when a vehicle is driving and turns a curve, it accelerates.

When decelerating, starting to climb a slope, finishing a climb, starting a descent, and finishing a descent, the fuel fluctuates greatly due to the weight acting on the fuel tank.
To detect the remaining amount of fuel, it is necessary to average the remaining fuel amount detection signal. A fuel gauge that displays the remaining fuel level by averaging the remaining fuel level detection signal is convenient because it can display the average remaining fuel level, but 1. Normally, the responsiveness of the fuel gauge, i.e., changes in remaining fuel level, is The responsiveness of the remaining amount display is selected based on when the vehicle is running, so if the amount of fuel in the fuel tank increases in a short period of time, such as when refueling, the amount of fuel will not increase until a certain period of time has elapsed. The problem is that the remaining amount is not displayed. On the other hand, when starting to drive the vehicle, the remaining fuel level needs to be displayed the moment the ignition key is turned to the accessory position, but if the averaging processing time of the detection signal is long, the ignition key is turned to the accessory position or There is a problem that the remaining amount is not displayed until a certain amount of time has passed after turning the ignition key. Therefore, the averaging processing time of the remaining amount detection signal is changed depending on the vehicle condition, and the fluctuation of the remaining amount detection signal is reduced by a long averaging processing time while driving, and a short averaging processing time is used when refueling or just before starting the engine. A fuel gauge has been proposed which improves the responsiveness of displaying the remaining fuel amount by measuring the remaining fuel amount detection signal based on the processing time (for example, Japanese Patent Publication No. 55-83897).

Figure 1 shows the circuit configuration of a fuel level meter configured to switch the averaging processing time using a microcomputer, and Figure 2 shows its flowchart.
In the figure, 1 is a high-precision fuel level sensor, 2 is a battery, 3 is an ignition switch, 4 is a processing circuit consisting of an input interface 41, a CPL 142, a memory 43, and an output interface 44, and 5 is a residue indicator. It is. If the ignition switch 3 is currently on, the remaining amount signal, which fluctuates slightly due to fluctuations in the fuel as the vehicle travels, is averaged to reduce measurement errors. Conversely, when the ignition switch 3 is off, the vehicle is stopped, so there is no fluctuation in the fuel (the remaining amount signal does not fluctuate, so the remaining amount signal measured in preparation for refueling is not averaged). In addition to detecting the state of the ignition switch, there is also a method of knowing that the vehicle is stopped by detecting the vehicle speed and knowing that the vehicle speed value is zero.

In this type of fuel level gauge, refueling is determined by detecting the on/off status U of the ignition switch and the vehicle speed value, but with the former method, even if the ignition switch is turned off before refueling, the refueling process is not completed. When you turn the ignition switch to the ON position to see the fuel level display, the remaining level signal is averaged and the display does not change easily even though the fuel is being refilled. .

In addition, with the latter method, if the vehicle speed is detected as almost zero, such as when driving slowly, it is determined that the vehicle is refueling even if it is not refueling, and the remaining amount signal is not averaged, so the remaining amount displayed value There is a problem in that the remaining amount cannot be accurately displayed because the amount fluctuates.

The present invention has been made in view of the above points, and provides a fuel gauge that detects the remaining amount of fuel, averages the remaining fuel amount signal, and displays the remaining amount.

In order to accurately display the remaining amount during refueling, when the remaining fuel amount signal is increasing, it is determined that refueling is in progress, and the averaging processing time is shortened or the averaging processing is canceled. .

The present invention will be explained below based on the drawings.

FIG. 3 is a block diagram showing the circuit configuration of an embodiment of the fuel remaining amount meter according to the present invention. A signal corresponding to the amount, that is, a remaining amount signal, is sent to an averaging circuit 6 to perform necessary averaging processing. The subtraction circuit 7 subtracts the signal from the remaining fuel amount sensor 1 and the signal from the averaging circuit 6, and sends the result to the comparator 8. The comparator 8 compares the signal from the remaining fuel amount sensor 1 with the signal from the averaging circuit 6 using the signal from the subtraction circuit 7.

Determines the increase in fuel and determines refueling. That is, when the signal from the fuel remaining amount sensor l exceeds the signal from the averaging circuit 6, it is assumed that the fuel has increased and it is determined that refueling is required. The selector 9 is a selector switch that selects whether to pass the signal from the averaging circuit 6 or the signal from the remaining fuel level sensor 1 based on the output of the comparator 8. Remaining amount calculation circuit 1
0 is the signal from the averaging circuit 6 or the remaining fuel level sensor 1
The remaining amount is calculated according to the signal from the controller, and the calculated remaining amount signal is sent to the display 5 to display the remaining amount.

FIG. 4 is a block diagram of the fuel level meter according to the present invention configured with a microcomputer. The microcomputer 4 has an input interface 41, a CPU 42,
It has a built-in memory 43 and an output interface 44. The input interface 41 outputs a display signal sent from the remaining fuel amount sensor l to drive the display 5.

The remaining amount signal sent from the furnace fuel remaining amount sensor 1 is processed by the microcomputer 4, and the remaining fuel amount is displayed on the display 5.

FIG. 5 shows a flowchart of arithmetic processing by the microcomputer in the embodiment shown in FIG. It is l.

In the first measurement, the measured remaining amount d1 is displayed as the remaining amount D1
This is displayed on the display 5. For the second and subsequent nth measurements, if refueling is not being performed at the time of the (n-1)th measurement, the (n-1)th displayed remaining amount Dn-1 is subtracted from the nth measured remaining amount dn.

If the result exceeds a certain increment A(J-), it is determined that refueling is in progress, and if it does not, it is determined that refueling is not in progress. When refueling is not in progress, averaging processing Dn = f (dn) is performed according to a predetermined calculation program, and the result Dn is displayed. On the other hand, when it is determined that refueling is in progress, flag F is set to 1' and the program jumps to the refueling processing program (encircled by a broken line). Also, if the flag F indicating that refueling is in progress is set before the i-th measurement (n l), the program jumps to the refueling processing program. In the refueling processing program, the measured 'lA amount dn is not averaged and is displayed as is.
and return to the main routine.

At this time, subtract the (n-1)th displayed remaining amount Inn-1 from the measured remaining amount dn, and if the result is not positive, that is, when dn≦Dn-1, a flag F = 1 indicating that refueling is in progress is set. Take it down. When dn>Dn-1, the program returns to the main routine with flag F set to 11'.

In this way, when (dnDn-1) exceeds a certain increment A, it is determined that refueling is in progress, and thereafter, the measured remaining amount is displayed without performing averaging processing until dn≦Dn-1 holds true. This program is relatively simple and places a small burden on the microcomputer.

FIG. 6 shows a second flowchart of the arithmetic processing of the remaining fuel gauge constructed using the microcomputer shown in FIG.

In this embodiment, it is determined that refueling is in progress when (dn-Dn-i) exceeds a certain increment A for a predetermined number of times eight or more consecutively.

The differences in operation from FIG. 5 will be explained. (dn-Dn-1
) exceeds a certain increment A, N is incremented by 1. If a certain increment A is not exceeded, N is set to OI and then conventional averaging processing is performed. Therefore, the value of N increases only if (dnDn-1) exceeds a certain increment N in succession. When the value of N exceeds a certain constant B, it is determined that refueling is in progress and the averaging process is stopped. This program is also relatively simple, and the response to refueling instructions is quick.

FIG. 7 shows a third flowchart of the calculation processing of the fuel remaining amount meter which is also configured by a microcomputer.

In this embodiment, it is determined that refueling is in progress when a monotonous increase in measurement data occurs more than a certain number of times in a row.
Points that differ from the diagram will be explained.

When the measured remaining amount dn in the nth measurement is larger than the measured remaining amount dn-1 in the (n-1)th measurement, N is incremented by 1. Conversely, when dn is smaller than dn-1, the averaging process is performed after N is set to O. Therefore, dn is a
If events larger than n-1 occur consecutively (when refueling d
n is never smaller than dn-1)
continues to increase. When this N exceeds a certain constant B, it is determined that refueling is in progress and flag F is set to 1'.

Although this program is somewhat more complex than the above two programs, the response to refueling instructions is relatively quick and there is less possibility of misjudgment.

FIG. 8 shows a fourth flow chart of the arithmetic processing of the fuel remaining amount meter configured by the -r microcomputer.

In this embodiment, it is determined that refueling is in progress when a monotonous increase in measurement data occurs a certain number of times or more and (dn-Dn-1) exceeds a certain increment A.

Differences from FIG. 5 during arithmetic processing will be explained. Similarly to FIG. 6, when dn is larger than dn-1, N is incremented by 1, and when it is smaller, it is set to 0.

When N exceeds a certain constant B, (dn-Dn-1) is compared with a certain increment A. If (dn-Dn-z) is smaller than A, averaging processing is performed, and if s (dn-Dn-1) is larger than A, it is determined that refueling is in progress, and $IIF is set in flag F.

FIG. 9 shows a fifth flowchart of the arithmetic processing of the remaining fuel gauge which is also configured by the microcomputer p"rc.

In this embodiment, when the measured data is larger than the displayed data, it is determined that refueling is necessary when the measured data increases continuously a certain number of times or more and (di-Da-1) exceeds a certain increment A. , points different from the above embodiment will be explained. First, dn and Dn-1 are compared, and if dn is larger than Dn-1, the process explained in the example of FIG. 8 is performed, and if dn is smaller than Dn-1, normal averaging is performed. Process.

Figure 10 shows the refueling determination according to the present invention for a capacitive fuel level gauge that prohibits the increase of the remaining amount -ia:= except when refueling, and cancels the prohibition of increasing the remaining amount display when refueling. FIG. 2 is a block diagram showing a basic circuit configuration when the above is applied. In the figure, a capacitance corresponding to the remaining amount of fuel is formed in the remaining melt 5 sensor 1, and this capacitance is detected by a detection circuit 15. The detection circuit 15 is composed of, for example, an R oscillator, and converts the CR oscillator into an oscillation pulse with an oscillation period corresponding to the capacitance generated by the fuel remaining amount signal S. This oscillation pulse signal is sent to the running judgment circuit 16. The driving judgment is then made.

The remaining amount detection signal is sent from the driving judgment circuit 16 to the signal processing circuit 17.
There, signal processing such as averaging processing, prohibition of increase in the remaining amount calculation 1 display number, and cancellation thereof are performed.

Figure il1 shows the circuit configuration of the signal processing circuit 17,
The signal processing circuit 17 includes an average cycle measuring section 18, an averaging processing section 19, a 1-display increase prohibition φ canceling section 20, and a remaining amount calculating section 2.
1, and FIG. 12 shows the signal processing circuit 17.
Figure 5 shows a diagram of the process when configured with a microcomputer. An oscillation pulse signal corresponding to the remaining amount of fuel is input to the input interface 17a of the microcomputer 17. The counter 17b is connected to the input interface 17a.
It has a built-in counter I that counts down in the same way as the oscillation pulse signal input to the clock generator 17c, and a counter ■ that counts down the clock signal sent from the clock generator 17c. Measures the period of the signal.CPU 17d uses memory 1
Averaging processing and remaining amount calculation are performed according to the program stored in 7e, and the calculated signal is output to the display 5 via the output interface 17f.

FIG. 13 is a flowchart F of an example t program of signal processing performed by the microcomputer shown in FIG. 12.

Now, a signal AO (n = 1.2, 3.
) has come in, and this fuel remaining amount signal b
Bn (
n = 1 e 2 m ” *・−・・・・・・).

First, initial setting is performed such that n=l, the contents of counter I of counter 17b are set to 0, and the contents of counter 2 are set to a predetermined value. The clock signal from the flock generator 17C is counted down, and when the count reaches 0, the remaining fuel amount signal M, which is the count value of the counter I, is read into the CPU 17d. At this time, n =
Since the remaining fuel level signal is red, the remaining fuel level Qn is calculated based on K (here, Ao is the fuel level signal when the remaining fuel level is 0, and is a constant) and is output to the display. Then, the counter 17b is initialized again with n = 2, and the CPU 17dJc reads the count value of the counter I when the count value of the counter ■ becomes 0. is compared with the averaged processed signal Bfm-1, and if An is larger than Bn-1 by a preset value (for example, 21) for converting the remaining amount, M
is used as Bn' and the remaining amount is calculated and displayed as is without performing averaging processing. Conversely, An is 2 than Bn-1
If the value does not exceed J-, averaging processing is performed using the following equation.

Here, M is a weighting coefficient. In this way, it is determined whether or not the averaged signal is smaller than Bn-1, and only when it is small, the remaining amount is calculated and displayed (increasing the amount is prohibited), and when it is larger, the remaining amount is calculated without being calculated. Try to repeat.

After that, n==3.4. . . . and performs similar processing to display the remaining amount.

In the processing operation shown in the flowchart in Fig. 13, whether or not to prohibit increase is determined by comparing temporally adjacent averaged processed signals Bn, but calculations are made from the averaged processed signals Bn. The remainder 'jjkQn may also be used. Furthermore, averaging processing may be performed before determining whether or not it is time to refuel.

In each of the above embodiments, the refueling decision is made based only on the remaining fuel level signal, but this method can be combined with conventionally known discrimination methods based on the on/off state of the ignition switch and the value of the vehicle speed signal. By doing so, the remaining amount of fuel can be displayed more accurately.

As explained above, in the present invention, it is determined that it is time to refuel when the increment of the remaining fuel amount signal exceeds a predetermined value. This method has the advantage that the remaining amount can be displayed more accurately and accurately than the conventional method of determining when to refuel.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram of a conventional fuel level gauge using a microcomputer, Figure 2 is a flowchart of signal processing of the conventional fuel level gauge shown in Figure 1, and Figure 3 is a fuel gauge according to the present invention. 2 is a flowchart illustrating different operations of the fuel gauge. FIG. 1θ is a functional block diagram of the fuel level gauge according to the present invention, fi! FIG. 11 is a block diagram showing a schematic configuration of the signal processing circuit shown in FIG. FIG. 12 is a block diagram when the signal processing circuit is configured by a microcomputer, and FIG. 13 is a flowchart showing an example of arithmetic processing in the microcomputer shown in FIG. 12. l...High-precision remaining fuel level sensor, 2...Battery. 3... Ignition switch, 4... Processing circuit, 5
...Remaining amount indicator S6...Averaging circuit, 7...Subtraction circuit, 8...Comparator, 9...Switcher, lO...Remaining amount calculation circuit, 15...Detection Circuit, 16... Driving judgment circuit, 17... Signal processing circuit, 17a, 41°44
...Input interface, 7b...Counter, 1
7C...Clock generator, -17d. 42-Cl'U, 17 e, 43... memory,
17f...Output interface, 18...° average cycle measuring section, 19...Averaging processing section, 20...Display increase inhibition/cancellation section, 21...Remaining amount calculation section Patent applicant
Hiroshi Suzuki, agent for Nissan Motor Company, patent attorney Figure 1 Figure 2 Figure 3 Figure 4 Figure 10 Figure 11 -, -17 Procedures Amendment Book December 29, 1982 1982 Short Poetry Application No. 166541 2, Name of the invention Vehicle fuel level meter 3, Relationship with the amendment case Patent applicant address Name of 2 Takaracho, Kanayō-ku, Yokohama-shi, Kanagawa Prefecture (39
9) Nissan Motor Co., Ltd. Representative Shun Ishihara 4, Agent Address 7 Tomowa Building, 3-4-16 Shiba, Minato-ku, Tokyo Contents of the Amendment The specification of the present application is amended as follows. (1) From the 2nd line to the 6th line of page 6, ``When the signal exceeds ...'' is changed to ``The signal is compared with a predetermined reference signal, and an increase in fuel is determined and refueling is performed. In other words, when the signal from the subtraction circuit 7 exceeds the reference signal, the correction is made. (3) Correct "B',," in the third line of page 15 to rBnJ. Figure 13 in the drawings of this application is replaced with the new Figure 13 attached hereto. List of attached documents listed in Figure 13 Official diagram rIJJ 1 copy

Claims (1)

[Claims] a remaining fuel amount sensor that detects the remaining amount of fuel and outputs a remaining fuel amount signal; an averaging processing means that averages the remaining fuel amount signal and converts it into a remaining amount display signal; refueling determination means for determining refueling based on the remaining amount display signal; and when the refueling determining means determines that refueling is in progress, the averaging processing time of the averaging processing means is shortened or the averaging processing is performed. averaging processing and control means for canceling;
A fuel level meter for a vehicle, comprising: display means for displaying the remaining amount of fuel based on the fuel display signal.