JPS62201320A - Fuel gauge for vehicle - Google Patents

Abstract

PURPOSE:To lessen an error in the reading of a fuel gauge by using fuel data when a fuel level is stable and calculating and displaying the residual fuel. CONSTITUTION:When a vehicle travels at a constant speed in the specific change width, for instance, + or -1km/h or + or -1 mile/h, the residual fuel is detected and it is decided whether or not the vehicle travels at the constant speed based on a signal from a travel distance sensor 2 in a decision circuit 9 so as not to renew the display as a rule at the time other than that. Then, when the decision circuit 9 decides that the vehicle travels at the constant speed, the residual fuel to be displayed is decided using data from a fuel sensor 3 with a processing circuit 14. In other words, since the display is renewed only when the vehicle travels stably with the speed more than the prescribed change width, the more accurate residual fuel can be displayed without displaying a measured value at the time of adjustable speed with a large measuring error.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel gauge for a vehicle that detects remaining fuel in a running vehicle such as an automobile or a motorcycle.

[Conventional technology]

Conventionally, as this kind of fuel gauge,
No. 60-20,019, etc., is known in which a float is used and the vertical movement of the float is converted into an electrical signal to obtain residual fuel.

[Problem that the invention seeks to solve]

The conventional fuel gauge float mentioned above moves up and down depending on the fuel level, so when the vehicle accelerates or decelerates, the fluid level fluctuates accordingly. When the remaining fuel is displayed on the display,
There was an inconvenience that the desired amount of remaining fuel could not be displayed. Therefore, as shown in Japanese Unexamined Patent Publication No. 57-187,616, the remaining fuel data is detected at a predetermined sampling period and averaged.
There is a problem in that the liquid level fluctuates greatly when the vehicle accelerates or decelerates, and the period of this liquid level fluctuation also varies, which may result in large measurement errors due to the relationship with the sampling period, etc. There is.

[Means for solving problems]

A predetermined variation range of the vehicle (for example, ±lkm/h or ±1
The remaining fuel is detected when the vehicle is traveling at a constant speed within m1le/h), and the display is not updated in principle at other times, based on the signal from the mileage sensor. A determination circuit is provided to determine whether or not the vehicle is traveling at a constant speed, and when the determination circuit determines that the vehicle is traveling at a constant speed, the remaining fuel is determined using data from the fuel sensor.

[Effect]

The remaining fuel display is not updated during acceleration and deceleration when there are large fluctuations in the fuel level.

〔Example〕

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the diagram, ■ indicates the vehicle's ignition switch (hereinafter referred to as TGN).
It is abbreviated as ) is ON or F, 2 is a well-known mileage sensor that outputs a pulse signal every predetermined mileage, and 3 is a well-known fuel sensor that converts the fuel level height into an electrical signal and outputs it. It is.

4 is a control circuit, which includes a counter 5 that counts the number of pulses from the mileage sensor 2, and a second counter 6 that counts the number of pulses from the mileage sensor 2 every predetermined period.
, a first comparator 7 that compares the count value of the first counter 5 with a preset value, for example, a value corresponding to 20 km travel, and outputs a signal if it is greater than the value, and a first comparator 7 that outputs a signal; Record the count value of 6 at each predetermined period tα
The value stored in this memory 8 and the value of the second counter 6 are within a predetermined width (for example, ±lk
m/h) for a predetermined time (for example, 20 seconds) or more, that is, whether or not the vehicle is traveling at a constant speed. -D converter 10, the A-D converter 10
A second memory 11 that stores fuel data, which is a digital value corresponding to the remaining fuel output from the second memory 11, stores the value of the second memory 11 at the time of refueling, and holds the value corresponding to the currently displayed value. The third memory 12 stores these second and third memos when the determination circuit 9 determines that the vehicle is traveling at a constant speed! a second comparator 13 for comparing the stored values of Jll, 12;
It consists of a processing circuit 14 that receives the output signals of the first comparator 7 and the second comparator 13 and performs processing such as adding or subtracting a predetermined number, for example, 1, to the stored value of the third memory 12. . Note that 15 is a display including a decoder and a driver, and the processing circuit 14 sends its output signal to the 36th memo 2 and the display 15.

The operation of this embodiment with the above configuration will be explained using the flowchart shown in FIG. In FIG. 2, FS is connected from the fuel sensor 3 to the second memory 1 via the A-D converter 1o.
Value (fuel data) according to the remaining fuel input to 1, FD
is a value (display fuel data) corresponding to the current display value stored in the third memory.

First, when the IGN is turned on, the
Input fuel data FS corresponding to the remaining fuel averaged by the means shown in Publication No. 616 into the second memory 11,
The display fuel data FD stored in the third memory when the IGN was last turned off is compared with the second comparator 13, and if the absolute value of the difference is 51 or more, fuel has been refilled or drained. The processing circuit 4 determines this, writes the value in the second memory 11 to the third memory 12, sends the value to the display 15 to display the remaining fuel, and below, the absolute difference between the above FS and FD is displayed. Moving on to the flow when the value is less than 51. In this flow, the counter 5 counts the data from the mileage sensor 2, adds up the mileage since the last time the display was updated, and this distance is 2.
When Qkm is exceeded, the comparator 7 sends an output signal to the processing circuit 14 and clears the counter 5, and the display 15 displays a value subtracted by 11. This is done based on the judgment that based on the average fuel of the vehicle, etc., if the vehicle travels 20 km, it will definitely reduce l/J, so it does not have to be 20 km, and this process may be omitted. When the above difference is 2Qkm or less, the value of the first memory 8 that stores the mileage data of the counter 6 that counts the signal from the mileage sensor 2 at a predetermined period and the mileage data of the counter 6 immediately before is stored. Compare and find the difference, for example ±lkm.
A judgment circuit 9 determines whether the range is within /h and whether it continues for 20 seconds or more, that is, whether or not it is running at a constant speed.
If the vehicle is not running at a constant speed, the previous display data F
D is displayed and when driving at a constant speed, the above-mentioned JP-A-57
- The fuel data FS corresponding to the remaining fuel averaged by the means shown in Publication No. 187.616, etc. is stored in the second memory 11.
The second comparator 13 compares the data in the second memory 11 with the displayed fuel data corresponding to the current displayed value held in the third memory 12, and if the FSO is larger, it is Assuming that the displayed fuel data FD up to that point was too small, the processing circuit 14 sent a number obtained by adding 1 to FD to the display 15 to update the display, and at the same time added 1 to the displayed fuel data FD up to that point. Store it in the third memo January 2 as the value. Also, if FSO is not larger, FD
= FS, and if they are not equal, it means that FD is larger, so the processing circuit I4 sends a value subtracted by 1 from the displayed fuel data FD to the display 15 to update it, and the third memory 12 stores that value. F
When D=FS, neither the display is updated nor the value stored in the third memory is rewritten.

After the processing of the processing circuit I4 as described above, IGN becomes ONL.
, then the process moves on to integrating the travel distance i4I L since the display update time again.

When the IGN is turned off, the displayed fuel data FD at that time and the mileage #L from the time of display update are written and held in a memory (not shown), respectively, for the next display, and the flow ends.

According to the above embodiment, the display is updated only when the vehicle is running stably within a certain range of change (±lkm/h in this case), so errors during acceleration and deceleration are large. It becomes possible to display the remaining fuel more accurately without displaying the measured value.

In the above embodiment, the mileage sensor 2 is used as a speed sensor, the first counter 5 is provided with a circuit for converting speed into distance, a memory is used in place of the counter 6, and the memory is stored at predetermined intervals. Even if the value is rewritten according to the output from the speed sensor, there is a problem because the speed sensor originally receives a signal from the distance traveled to determine the speed, and the fuel sensor 3 outputs a digital value. In this case, the A-D converter 10 is not required. In addition, the determination as to whether or not the vehicle is running at a constant speed may be made under any conditions other than the above-mentioned condition of continuous driving within ±lkm/h for 20 seconds or more, as long as the fuel level is stable.

Furthermore, considering driving on slopes and curves, if an accelerometer or inclination sensor is installed and the optimal remaining fuel is determined from the output of the accelerometer and the output of the fuel sensor, it will be even better.
Errors can also be reduced by selecting the optimum mounting position of the fuel sensor with as little variation as possible in accordance with the shape and size of the fuel tank.

Furthermore, in the above embodiment, when the traveling speed is zero, that is, when the vehicle is idling, it is considered to be constant speed traveling, but other processing may be performed during idling, and it is better to average the fuel data FS. Although it is preferable, it is not necessary to carry out this process unless it is particularly necessary.Furthermore, the processing circuit 14 integrates the magnitude relationship between FD and FS compared by the second comparator I3 several times, and when a certain value is reached, It may also include processing to update the display.

〔Effect of the invention〕

According to the present invention, since the remaining fuel is determined and displayed using fuel data when the fuel level is stable, it is possible to display the remaining fuel with small errors.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a flowchart explaining its operation. 2.-Midage sensor 3...-Fuel sensor 5.6-Counter 7.13-Comparator 8, 11.12--Memory 9--Judgment circuit 14-Processing circuit 15--Display device

Claims (1)

[Claims] A mileage sensor that outputs a signal every predetermined mileage, a fuel sensor that outputs a signal corresponding to the remaining fuel, and whether the vehicle is running at a constant speed within a predetermined variation range based on the output signals of the mileage sensor. a determination circuit that determines whether or not the vehicle is traveling at a constant speed; and a processing circuit that determines remaining fuel to be displayed using an output signal from the fuel sensor when the determination circuit outputs a signal indicating that the vehicle is traveling at a constant speed. A vehicle fuel gauge characterized by having: