JPS6082928A - Fuel remaining quantity meter for vehicle - Google Patents

Abstract

PURPOSE:To eliminate an erroneous display by adding a prescribed quantity to a fuel remaining quantity value detected by a fuel sensor, and displaying it until a vehicle runs after refueling. CONSTITUTION:In case of refueling is not executed, a fuel remaining quantity value outputted from a time averaging circuit 3 is sent directly to a driving circuit 4 by a switching circuit 7, and displayed as it is on a display device 5. On the other hand, when refueling is executed, when the switching circuit 7 receives a signal of its fact from a remaining quantity deciding circuit 9, the fuel remaining quantity value is sent to a remaining quantity value correcting circuit 10 only it is decided that a vehicle stops, by a car speed sensor 11 and a running deciding circuit 12, and in this circuit 10, a set value is added.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a vehicle fuel gauge that accurately displays the remaining fuel amount immediately after refueling.

(b) Prior art Conventionally, a needle-type fuel gauge has been used to display the ffl remaining in the fuel tank of a vehicle, but recently
There is a trend toward the use of digital fuel level gauges using i-electronic circuits. Figure 1 is a block diagram of a digital fuel level gauge. 1 is a sliding resistance type installed in the fuel tank that converts the fuel level into a resistance I- and outputs it in the form of an electrical signal. In the fuel sensor, the remaining amount signal output from the fuel sensor 1 is converted into a digital value by an A/D converter 2.

The time averaging circuit 3 outputs the A/D-transformed remaining amount signal in this way.
Calculate the remaining amount by averaging at regular time intervals.

This remaining amount value is displayed on the display 5 via the driver circuit 4, and the display value is updated by a display update signal outputted from the refresh circuit 6 at regular time intervals.

By the way, as a sliding resistance type fuel sensor for this type of digital fuel remaining meter, a resistance plate is erected perpendicular to the fuel liquid level in the fuel tank, and a float floating on the liquid level is connected to the upper and lower sides of the resistance plate. A type of contact is used in which the movable contact is pressed by a spring and slides up and down as the liquid level changes, and the position of the contact, which changes as the fuel level increases or decreases, is converted into a resistance value, which indicates the remaining amount of fuel. A quantity signal is obtained.

With this type of fuel sensor, there is no problem when the fuel level fluctuates up and down violently, but when the fuel level rises quietly, such as when fuel is pumped up and down at a gas station, the contact Due to the frictional force between the float and the resistance plate, the contact rises with a delay in the rise of the float, so when the tank is full and refueling is complete, the liquid level stops rising and the float stops, the contact moves to the resistance plate. It ended up stopping at a slightly lower position than its original position due to friction. For this reason, is it detected by the position of the contact? There is a problem in that the displayed value of the remaining amount of fuel is less than the actual amount of refueling (actually about 2). In the case of a conventional folding type fuel gauge, the reading M degree is not very high, so this kind of display error, which is less than 2t at most, is not a problem, but in the case of a digital fuel level gauge, the display accuracy is high, so it is not a problem. This problem may cause the driver to misrecognize the remaining amount.

(c) Object and structure of the invention The present invention has been made in view of the above points, and an object of the present invention is to accurately display the remaining fuel amount immediately after refueling in a sliding resistance type fuel remaining gauge, and for this purpose. After refueling and before driving, a predetermined amount is added to the remaining fuel amount detected by the fuel sensor, and the entire corrected value is displayed.

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

FIG. 2 is a block diagram of one embodiment of a fuel level gauge according to the present invention, in which the same components as in FIG. 1 are designated by the same reference numerals. This embodiment has a switching circuit 7, a remaining amount value storage circuit 8, a remaining amount determining circuit 9,
Remaining amount value correction circuit 10, vehicle speed sensor 11, running determination circuit 1
2 is further provided, and 13 is an ignition switch.

Next, the remaining fuel display operation by the fuel remaining amount meter will be explained based on FIG. 2 and FIG. 3 showing a flowchart.

When the ignition switch is turned on, the remaining amount signal output from the fuel sensor 1 is A/D converted by the A/D converter 2 (P-1).In this state, the program enters an interrupt wait state (P-2).

When there is an interrupt command, the remaining amount is calculated as follows (P-3). That is, the remaining amount signal converted into a digital signal by the A/D conversion 'ar2 is averaged by the time averaging circuit 3, updated as a remaining amount value by the refresh circuit 6 at fixed time intervals, and sent to the switching circuit 7. .

On the other hand, refueling judgment is made as follows (P-4). That is, the remaining fuel value sent from the driver circuit 4 to the display 5 is stored in the remaining amount storage circuit 8 when the ignition switch 13 is turned off. Now ignition switch 13
When turned on, the remaining fuel amount stored in the remaining amount memory circuit 8 when the ignition switch 13 was turned off last time and the remaining fuel amount currently calculated and sent to the switching circuit 7 are stored. The quantity determination circuit 9 compares the amount, and if the difference is above a certain value, it is determined that the oil has been supplied, and if the difference is below the certain value, it is determined that the oil has not been supplied, and a notification to that effect is sent to the switching circuit 7. In this embodiment, the remaining amount storage circuit 8 and the remaining amount determining circuit 9 constitute a refueling determination circuit.

In addition to being able to determine whether fuel has been refueled by the method described above, it may also be determined manually by providing a refueling switch and turning it on.

When refueling is not performed, the remaining fuel value outputted from the time averaging circuit 3 is directly sent to the driver circuit 4 by the switching circuit 7, as in FIG. 1, and is displayed as is on the display 5 (P-5). On the other hand, when the switching circuit 7 receives a signal to that effect from the remaining amount determination circuit 9 when refueling is performed, the vehicle speed sensor 11 and the running determination circuit 12 determine that the stroke has stopped when the vehicle speed is zero. I was wrong (
Only in case P-6), the remaining fuel amount value is sent to the remaining amount value correction circuit 10, and the set value is added here. Since the set value to be added is the display error when the tank is full, at most 2 is the following preset value. The pressure in the remaining amount correction circuit 10 is sent to the driver circuit 4 and displayed on the display 5 as (remaining amount set value) (P-7). As a result, the displayed value of "remaining fuel when the tank is full" can be made to substantially match the actual amount of fuel supplied.

After that, the vehicle starts running, and the running signal is sent to the switching circuit 7 by the vehicle speed sensor 1] and the running judgment circuit wj12.
When the switching circuit 7 manually performs the correction operation up to that point, that is, the calculated remaining amount output from the time averaging circuit 3? Sending to the remaining amount value correction circuit 10 is stopped, the amount is sent directly to the driver circuit 4, and the display operation is switched to normal arithmetic operation to perform normal remaining amount display (P-8). In this way, when the vehicle starts running after refueling, the remaining amount display is corrected (tm) and then switched to the normal display operation because the fuel level in the fuel tank fluctuates as the vehicle runs, causing the float of the fuel sensor to change. This is because the frictional force between the contact point and the resistance plate momentarily decreases as the contact point moves up and down, and the contact point comes to the normal position tm, eliminating any error in the remaining tiL display.

In the above embodiment, the display and correction of the remaining amount value were realized by the circuit configuration, but it is of course possible to perform program processing using a microcomputer.

As explained above, in a fuel level meter using a sliding resistance type fuel sensor, the present invention adds a predetermined amount to the fuel level value detected by the fuel sensor until the vehicle is driven after 1J of oil has been poured. Since the fuel sensor is displayed in a full tank, it is possible to eliminate erroneous display that tends to occur because the contact point of the fuel sensor does not move to the fixed position due to friction when the tank is full.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional fuel level meter, FIG. 2 is a block diagram of an embodiment of a fuel level meter according to the present invention, and FIG.
The figure is a flowchart of the display operation of the fuel level gauge according to the present invention.

Claims (1)

[Claims] In a fuel gauge using a sliding resistance type fuel sensor, a fuel remaining amount correction means is provided that adds a predetermined amount to the fuel remaining amount value detected by the fuel sensor during the time when driving is started after refueling is completed. A fuel level gauge for a vehicle characterized by being provided with a fuel level gauge.