JPS5892824A - Digital display system for residual quantity of fuel - Google Patents

Abstract

PURPOSE:To suppress the variance of the display value of the residual quantity of fuel, by issuing a data signal indicating the residual quantity of fuel at intervals of a certain timing and comparing the current data signal with the preceding data signal and changing the data signal if they do not coincide with each other. CONSTITUTION:When a key switch 61 is turned on, a pulse from an initializing part 6 and a pulse (Q1) from a timing generator 4 are inputted to an AND circuit 65, and a set signal is given to a latch circuit 31a through OR circuits 34a and 34b, and a signal of the residual quantity of fuel of a level sensor 1 is read through an AD converter 2 and is sent to a display part 5 through a latch circuit 31b. When the next pulse (Q3) from the timing generator 4 is outputted, the preceding output from the circuit 31a and the current output from the AD conveter 2 are sent to a comparator 33; and if they do not coincide with each other, the circuit 31b is triggerred by the signal from an AND circuit 40 to change the display. Thus, the variance of the display value of the residual quantity of fuel is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital fuel remaining amount display system that measures the liquid level of a fuel tank mounted on a motor vehicle and displays the remaining fuel amount in a digital amount.

A bimetallic or differential coil type meter was used, which was connected to a variable resistance level sensor whose resistance value changed, and which showed a pointer deflection angle proportional to the resistance value, and began to display the remaining fuel level in analog form. In recent years, instead of the 7spg type fuel remaining amount display method, a digital winding charge remaining amount display method has been adopted that uses a digital display element to display the remaining fuel amount on a digital lid. There is a tendency to

However, unlike analog types, digital types do not have a fluctuation suppression function that prevents the display from fluctuating much even if the liquid level fluctuates due to the lag characteristic of the fuel remaining amount display system. The disadvantage is that the display of the remaining amount fluctuates as the liquid level changes.

The drawback of this problem is that the level sensor that measures the liquid level should have a structure that is less susceptible to the effects of liquid level fluctuations, or the output of the level sensor should be integrated. Fluctuations in the liquid level are relatively large. In particular, the latter method does not process the signal as a series of digital data signals, and is unsuitable for signal processing by general-purpose IC circuits or ICP combinators. In the end, both of the above methods are not optimal methods for suppressing display fluctuations in a digital fuel remaining amount display method.Therefore, this invention provides a novel method that can suppress the display fluctuations by processing digital data signals. It is an object of the present invention to provide a display method and solve the above problems.From the above object, the present invention emits a digital data signal indicating the remaining fuel amount at regular timings, and The digital data signals are compared, and the currently displayed digital data signal is controlled based on the comparison result〇Hereinafter, embodiments of the present invention will be explained according to the drawings〇 Figure 1 shows the present invention. 1 is a block diagram showing an overview of the digital fuel remaining amount display system, in which 1 measures the liquid level in a fuel tank (not shown) in total and issues an ANA 4&-# signal indicating the remaining fuel amount. The level sensor 0 is constituted by, for example, a known variable resistance level sensor whose resistance value changes depending on the liquid level.

A that converts a single signal into an n-bit digital data signal
-D converter; 3 is a signal comparator for comparing the digital signals of the digital data signals; 4 is a timing generator for emitting timing pulses for controlling the A-Dll' converter 2 and the signal comparator 3; The display unit is composed of, for example, a seven-segment digital display element (not specifically shown) whose display is switched according to the digital data signal output from the comparator 3.

Note that 6 is an initialize section that initializes the display on the display section 5 at the engine start time.
The signal comparator 3 applies a digital data signal indicating the remaining amount of fuel, which is an output signal of the A-D converter 2 that performs signal comparison to be described later, to the display section 5, and the display section 5 displays the signal indicated by the digital data signal. Display the initial value.

A digital data signal indicating the amount is output at regular timing. On the other hand, the signal comparator 3 operates according to the timing pulse generated by the timing generator 4.
In addition to executing the signal comparison described later, the digital data signal applied to the display section 5 is changed according to the digital data signal emitted from the A-D converter 2 depending on whether the comparison result satisfies the conditions described later. In this way, the display on the display unit 5 is prevented from changing due to changes in the liquid level.
〇 2nd @ is a circuit diagram showing another example of the real circuit of the block in Fig. 1, which will be explained together with the specific circuit of the block in Fig. 1. In the figure, the parts corresponding to each block in Fig. 1 are indicated by dashed lines. The level sensor l shown with the same reference numerals as in the box in FIG. It consists of a resistor 12 that applies a power supply voltage (Vce) to the output terminal 12, and its output terminal 13 emits a 7 analog signal with a voltage value proportional to the remaining amount of fuel. The output terminal 13 of the level sensor l is an A-D converter. This A-D converter 2 has its conversion command signal input terminal conv connected to the output terminal Q4 of the timing generator Shizu which will be described later, and the above-mentioned output is connected to the input terminal conv. The signal comparator 3 converts the 7-bit signal into an n-bit digital data signal every time a timing pulse generated from the terminal Q4 is input as a conversion command signal. The signal comparator 3 is a latch circuit 31a*31b.

The front-stage latch circuit 31a, which is composed of a counter 32 and a comparison circuit 33, has a clock terminal T connected to the output terminal of the OR circuit 34m, and the output of the OR circuit 34m to the tarlock terminal T as a trigger pulse. When input, the latch circuit 111b reads the output signal of the A-D converter 2 applied to the data terminal and outputs it to the next stage latch circuit 31b. Similarly to the above, it receives the output of the off circuit 34b, reads the output of the latch circuit 31a in the previous stage, and outputs it from the output terminal.

On the other hand, the above A-D conversion! 112 and the number of bits of the output signal of the latch single converter 2 and latch circuit 31m in the previous stage is n, where m is smaller than n) is input to the comparison circuit 33.◎This comparison circuit Reference numeral 33 denotes a circuit for detecting coincidence between two persons, which is constituted by an exclude-jib-off circuit, etc., provided according to the number of bits of the input signal, and its output terminal Q is connected to one input terminal of the AND circuit 36. They are each connected to one input terminal of an AND circuit 37 via an inverter 38.

The output terminal of the AND circuit 36 is connected to the count input terminal T of the counter 32, and the AND circuit 37 is connected to the reset terminal R. , and its N output terminal N is connected to one input terminal of the AND circuit 40 .

Note that the output terminal of the AND circuit 4o is connected to the
4b, and one input terminal of the seven circuits 34m is connected to the output terminal Q3 of the timing generator 4, which will be described later, together with the conversion command signal input terminal con of the A-D converter 2. 1iIIR has been done.

Therefore, the signal comparator 3 detects whether or not the A-D converter 2 continuously issues digital data signals indicating the same remaining amount of fuel.

The timing generator 4 has a reset terminal R and timing pulse output terminals Ql, Qz, Qs,
The reset terminal R is the conversion completion signal output terminal sts of the A-D converter 2, the output terminal Q1 is the other input terminal of the AND circuits 36 and 37, and the output terminal Q2 is the other input terminal of the AND circuit 40. , the output terminal Q3 is connected to the above A
- It is connected to the conversion command signal input terminal conv of the D converter 2 and one input terminal of the OR circuit 34m, respectively. This timing generator 4 includes an oscillator, a counter, a crystallizer, etc., although not shown in detail.
I have been configured 9, and the above A-D converter 2 is connected to the set terminal R.
While the conversion completion signal issued by A-
During the signal conversion operation of the D converter, the 0 display unit 5 is reset and thereafter sequentially outputs timing pulses to each output terminal Q1 to Qs.
For example, the decoder 51 is composed of a 7-segment digital display element 52 that displays a base number, and the output of the latch circuit 31b of the signal comparator 3 is used as a BCD input.
The digital display element 52 receives the code signal and displays a number indicating the remaining amount of fuel.0 Furthermore, the minimum increment of the fuel remaining amount display on the display section 5 is , t (liter) is the capacity of the fuel tank divided by the maximum value of the digital data signal, and is not necessarily 1.
0 not in liter increments Initial rice part 6 is key switch RO 1 and resistor 62
This output terminal 64 outputs a differentiated pulse obtained by differentiating the switch signal of the key switch 61 from the output terminal 64.
The output terminal is connected to one input terminal of an AND circuit 65 whose output terminal is connected to the other input terminal of the above-mentioned A circuit 34.The other input terminal of the AND circuit 65 is connected to the output terminal of the timing generator 4. Connected to Q1.

Next, the operation of the circuit shown in FIG.
The explanation will be based on the time chart shown in the figure.

In Fig. 143, (A) indicates the output of the output terminal 64 of the initial rice section 6, and (R), (C), and (1) indicate the output terminals Q s , Q z , of the timing generator 4.
(e) is the output of the conversion completion signal output terminal sta of the A-D converter 2, (f) is the output of the AND circuit 65, and (g) is the output of the output terminal Q of the comparison circuit 33. output,
(A) indicates the output of the AND circuit 36, (S) indicates the output of the AND circuit 37, (X) indicates the output of the output terminal N of the counter 32, and (2) indicates the output of the AND circuit 40. When the intermediate switch 61 is turned on at time t to start the process, a differential pulse Po (see Fig. 3 H) is generated from the output terminal 64 of the initial rice section 6. Therefore, the AND circuit 6S is another input signal, the timing pulse Pl output from the output terminal Q1 of the timing generator 4 (ll113(b)).
] is issued, an initial set pulse P5 (see FIG. 3) is output. This initial set pulse pm is sent to the clock terminal T of both latch circuits 31 and 31b of the signal comparator 3 via OR circuits 34a and 34b, and is applied to the A-D converter 2 which converts the data signal into a digital signal.
The next stage latch circuit 31b reads the output of the latch circuit 31a and outputs the digital data signal. is applied to the decoder 51 of the display unit 5, and therefore the digital display element 52 displays the remaining fuel amount as 1. 0, which is the initial value indicated by the digital data signal.Next, at time i1, the timing pulse Pa[413
See figure (d)] is issued, the above A-D conversion! ij
2 receives this timing bus P3 as a conversion command signal and converts the level controller 7 delog signal at the time tI into a digital data signal (hereinafter simply referred to as A-
At the same time as starting the D conversion operation), the latch circuit 31g receives the timing pulse PRk
Read the output of converter 2 (digital data signal indicating the remaining fuel amount before the previous measurement timing, time i0). Here, if the remaining fuel amount is decreasing or increasing at time jl, A-D The digital cap of the digital data signal emitted from the converter 2 is smaller or larger than the digital amount of the output signal of the latch circuit 31a, which is the digital data signal at the previous measurement timing (before time io). Therefore, even if the A/D conversion operation based on the timing pulse ps issued at time jl is completed, the comparator 33 does not output the match pulse P6 indicating that the inner inputs match. - On the other hand, the above A-D
Until the conversion operation is completed, the conversion completion signal output terminal 1
From 1ta onwards, the sta pulse 1 P4 (see Fig. 3 ←)] i output is 6, and the timing generator 4 is reset.

When the above-mentioned A-D conversion operation is completed, the above-mentioned reset is released, and the timing pulse P1゜pg (see @s figure middle), (c)] is transmitted from each output terminal QI, Qt to the third output terminal until time t2.
Next output.

Therefore, when the timing pulse P1 is emitted, the AND circuit 37 activates the reset pulse ps (see FIG. 8113).
Since the 0 counter 32 is reset, even if the timing pulse P2 is generated, the AND circuit 40 does not output the tri-force pulse p.
*o (3rd drop ←) 14) No specific output at t' and does not trigger the latch circuit 31b 〇 As a result, the remaining fuel amount display on the display unit 5 does not change and remains at the above initial value 〇 Time t2 , when the timing pulse pm is emitted again from the output terminal Q3 of the timing generator 4, the latch circuit 31a changes the A-D at time t1.
Read the output of f exchanger 2 at 〇knee, the remaining fuel amount is at time t.
If it is assumed that the remaining fuel amount decreased or increased at time t'1 up to n, then the digital amount of the digital data signal issued from the A-D converter 2 is equal to the digital amount at the previous measurement timing (time t1). Equal to the digital quantity of the output signal of the latch circuit 31a, which is a data signal, the comparator circuit 33 outputs a coincidence pulse P660.
When the timing pulse P1 is issued after the time t2, the AND circuit 36 outputs the count pulse py (see FIG. 3 (a)) and increments the counter 32. Thereafter, the timing pulse is output in the same manner until the time tn. The count pulse P7 is output every time P1 is issued.

When the count pulse P7 is continuously outputted a predetermined number of times in this manner, the counter 32 counts the count pulse P7 and outputs a count output pulse ps [see FIG. 3 (N)] from the output terminal N.

After this count output pulse P- is output, when a tying pulse P is issued from the output terminal Q2 of the timing generator 4, the AND circuit 40 outputs a trigger pulse pto. , the latch circuit 31b converts the output of the previous stage latch circuit 31a to A-DI'! after time t1. The output of the II unit 2 is read and a data signal is output to this digital signal.

Therefore, the display of the remaining fuel amount on the display section 5 changes to a display of a decreased or increased remaining fuel amount indicated by the digital data signal.

If the liquid level fluctuates widely at time tn, the above comparison condition will not be satisfied and the above time points i1 to t! The counter 32 is immediately reset, and the above operation is repeated thereafter, but by resetting the counter 32,
The AND circuit 40 does not output the trigger pulse pIo, and the latch circuit 31b does not read new data. Therefore, the display on the display section 5 continues the previous display, and: 1 The above liquid level fluctuation The display is prevented from fluctuating due to the effects of are equal a predetermined number of times j! ! Comparison of signals to determine whether or not to control the fuel is performed repeatedly, and the display on the display unit 5 is changed according to the comparison result, so that a stable display of the remaining fuel amount is made without being affected by fluid level fluctuations. In the circuit of FIG. 2, the initialization section 6 can be omitted depending on the case, and the ratio is
Although the responsiveness of the display is improved without resetting , almost the same effect can be obtained by inputting all n bits to the comparator circuit 33.

In the explanation of the above embodiment, the measurement timing of one fuel remaining, that is, the frequency of the timing pulse, was not particularly mentioned. However, since the decrease or increase in the remaining fuel amount changes relatively slowly, the measurement timing is set to seconds. By setting the frequency of the timing pulse as a unit, that is, setting the frequency of the timing pulse to about 1 to I GHz, the display on the display can sufficiently follow the change in the remaining fuel amount. It is desirable that the display be linked to the pm switch, for example, so that the remaining fuel amount is displayed only while the engine is operating.Furthermore, in the above embodiment, if the level sensor is a digital level sensor, of course An AD converter becomes unnecessary. However, a latch circuit or the like is required to memorize the output of the level sensor at each measurement timing.The signal processing performed by the circuit shown in FIG. Therefore, the present invention is not limited to the above-mentioned two circuit sides.

As explained above, according to the present invention, a digital data signal indicating the remaining amount of fuel is generated at regular timings, and the digital amount of the digital data signal at the current timing and the digital data signal at the previous timing is calculated. A signal comparison is performed to compare whether or not the values match, and the currently displayed digital data is changed according to the comparison result. Through a series of digital data signal processing, the remaining fuel level due to fluid level fluctuations is changed. It is possible to have a function of suppressing fluctuations in the display, and it is possible to provide a digital fuel remaining amount display method that eliminates the above-mentioned conventional drawbacks.

This invention is a digital fuel remaining amount display method based on a series of digital data signal processing, and can be used when an IC circuit or a dichroic fuel pump is installed in an automobile for the purpose of controlling various loads. can be easily implemented.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the digital fuel remaining amount display system according to the present invention, Figure 2 is a circuit diagram showing a specific circuit example of the block in Figure 1, and Figure 3 is the operation of the circuit in Figure 2. Explanatory time chart @l... Level sensor 2... A-D converter 3... Signal comparator 4... Timing generator 5... Display section 6... Initialization section patent Applicant Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] (1) Measure the remaining amount of fuel in the fuel tank mounted on the vehicle at regular timings, emit a digital data signal indicating the remaining fuel amount, and compare the digital data signal at the current measurement timing with the one at the previous measurement timing. Compare both digital quantities with the above digital data signal or the currently displayed digital data signal, and when the above two digital quantities are equal for a preset number of consecutive times, the currently displayed digital data signal is changed to the above digital data signal. A digital fuel remaining amount display method characterized by (2) In the method described in claim 1, a digital data signal indicating the remaining fuel amount is input to a latch circuit that is triggered in synchronization with the measurement timing. Then, the output signal of this latch circuit and the above digital data, the @ number, are input to a comparison circuit that detects a match between two people, and the output of this comparison circuit is input to a counter, and the output of this counter is received. Digital fuel remaining amount display method 0 characterized by changing the currently displayed digital data signal to the output signal of the latch circuit.