JPH0369054B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) This invention relates to a fuel remaining amount display device for automobiles, and particularly relates to a fuel remaining amount display device for an automobile, and in particular, a fuel remaining amount display device that displays a remaining amount of fuel by an electric signal given by a gauge installed in a fuel tank. A first remaining fuel amount detection device that detects the amount of fuel remaining, and a second remaining fuel amount detection device that detects the amount of fuel used by the engine and calculates the remaining amount of fuel using an electronic circuit based on this amount of fuel used. The present invention relates to a fuel remaining amount display device for an automobile.

(Prior Art) Conventionally, as described above, a remaining fuel amount display device has a first remaining fuel amount detection device that displays based on a gauge and a second remaining fuel amount detection device that displays based on fuel consumption amount. For example, a device described in Japanese Unexamined Patent Publication No. 57-73625 is known.

In addition to the first and second remaining amount detection devices, this conventional device includes a third remaining fuel amount detection device that calculates the remaining amount from a predetermined fuel reduction rate corresponding to fuel leakage. When the detected value of the remaining fuel amount detection device is smaller than the detected value of the first remaining fuel amount detection device, the remaining amount of the second remaining fuel amount detection device is displayed, and conversely, the second remaining fuel amount detection device displays the remaining amount of fuel. When the detection value of the device is larger,
Calculating the remaining amount using the third remaining fuel amount detection device,
As a result, if the calculated value of the third remaining fuel amount detection is smaller than the detected value of the first remaining fuel amount detection device,
The first remaining fuel amount device displays the remaining fuel amount, and in the opposite case, the third remaining fuel amount detection device displays the remaining fuel amount.

(Problems to be Solved by the Invention) However, this conventional device has the following problems.

In other words, the second remaining fuel amount detection device, which calculates the remaining amount based on the amount of fuel used by the engine, calculates the remaining amount of fuel from which the amount of fuel used is subtracted each time the engine stops. It is rewritten to the remaining amount detected by (initialization). Although this is an effective means for accurately detecting the remaining amount even if refueling is performed midway through, there is a problem in that the control becomes complicated and the circuit configuration becomes complicated and expensive. Moreover, this first remaining fuel amount detection device, which detects the remaining fuel amount based on the fuel level, generally has a poor start-up at startup and the detected remaining amount at that time is not accurate, so if calculations are performed based on the detected value at this time. There is also the problem that accurate display is not achieved.

In addition, in the conventional device described above, when the fuel level drops due to the tilting of the vehicle body, etc., as can be seen from Figure 3 of the conventional publication, the third remaining fuel amount detection is performed at the initial stage of the drop in the fuel level. Based on the device, the remaining fuel amount is displayed at a predetermined rate of decrease, and then, as the liquid level returns, the first remaining fuel amount detection device (gauge) displays the remaining fuel amount at a rate of increase associated with the return of the liquid level. When the detection values of the first and second detection devices match, the display returns to the display by the second detection device. In this way, the display shows that the remaining fuel amount, which should be decreasing as the vehicle travels, is increasing (as shown in the area _B2 in the same figure).

On the other hand, people generally don't pay much attention to the fuel gauge when there is a lot of fuel remaining, but when the fuel level is low, they often look at the fuel gauge while calculating the possible mileage. , more accurate display is required. However, in the conventional technology, the method of switching the display does not change whether the remaining fuel is high or low, so when the fuel is low and you frequently look at the display, the remaining fuel may be left as described above. There has been a problem in that the displayed value of the amount may increase midway through, giving the driver a sense of distrust in the accuracy of the display.

(Object of the Invention) The present invention has been made based on the above-mentioned circumstances, and is intended to simplify the circuit configuration and reduce the cost of the second remaining fuel amount detection device, and to reduce the cost when the remaining fuel amount is low. From now on, we have made it possible to display highly accurate information without creating a sense of distrust, such as when the amount remaining on the display increases while driving, while also supporting refueling when the tank is less than full. An object of the present invention is to provide a fuel remaining amount display device for an automobile that does not display incorrectly.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a first fuel remaining amount that detects the remaining amount of fuel by an electric signal given by a gauge installed in the fuel tank. When the remaining amount detected by the first remaining fuel amount detection device reaches a predetermined amount, which is a scarce amount that requires early refueling, it is activated, detects the amount of fuel used by the engine, and sends an electric signal to the electronic circuit. a second remaining fuel amount detection device that calculates the remaining amount of fuel by subtracting the amount of fuel used from the predetermined amount; When the remaining fuel amount is high, the remaining fuel amount is displayed by the output signal of the first remaining fuel amount detection device, and on the other hand, when the remaining amount detected by the first remaining fuel amount detection device is below the predetermined amount, the second remaining fuel amount is displayed. A selection circuit is provided for displaying the remaining amount based on the output signal of the amount detecting device.

(Operation of the Invention) In the present invention, while the remaining fuel amount is sufficient and there is generally no need to know the remaining fuel amount in detail, the remaining fuel amount is determined based on the output signal of the first remaining fuel amount detection device. Is displayed. Therefore, in this state, some error will occur due to the tilt of the vehicle body, etc., but since the remaining amount is not so much of a problem, this error can be ignored, and during this period, the fuel supply that is not full will be used as fuel. Even if damage is caused by extraction, the remaining fuel level will be displayed without any effect.

Next, when the remaining fuel amount detected by the first fuel detection device becomes less than a predetermined amount, which is a scarce amount that requires early refueling, and a highly accurate display is required, the second fuel remaining amount is detected. The detection device detects the remaining amount by starting calculation to subtract the amount of fuel used by the engine from the predetermined amount, and at the same time, the selection circuit detects the remaining amount based on the output signal of the second remaining fuel amount detection device. It is switched so that the display is made.

Therefore, it is possible to accurately grasp the remaining travel distance and refuel appropriately. Furthermore, in this state, it is possible to display the display in small increments based on highly accurate detection, and since the amount used is subtracted from the predetermined amount, there is no need to display an increase in the amount remaining. The display does not give a sense of distrust. Furthermore, since the predetermined amount is an extremely small amount that requires refueling at an early opportunity, if refueling is performed after the predetermined amount is below, the predetermined amount will normally be reached even if the tank is not full. Therefore, the display is switched again to the first remaining fuel amount detection device, and there is no inconvenience of always having to fill up the tank when refueling.

In this way, since the second remaining fuel amount detection device is configured to subtract the amount of fuel used from a certain value,
It is easy to control, and it is possible to simplify the electronic circuit and reduce costs.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, regarding the embodiment shown in FIGS. 1 to 3,
Its configuration will be explained.

FIG. 1 shows a system diagram according to an embodiment of the present invention.

According to the figure, a first remaining fuel amount detection device 10,
A second remaining fuel amount detection device 11, a selection circuit 12, and a display circuit 13 are shown.

The first fuel remaining amount detection device 10 obtains an electric signal (hereinafter referred to as a gauge signal) g given by a gauge installed in a fuel tank.
A well-known gauge is one that outputs the remaining fuel level as an electrical signal by printing a sheet-like resistor on a board and short-circuiting this with a contact provided on a float. (Refer to pages 10-71 of Tosho Publishing Co., Ltd., 1981).

The second remaining fuel amount detection device 11 calculates and detects the amount of fuel used on the engine side as described later. Basically, the amount of fuel flowing into the engine is detected from the injection time of the injector, and is finally given as a pulse signal (hereinafter referred to as consumption signal) e. FIG. 2 shows an example of this second remaining fuel amount detection device 11, and this device 11 is composed of a valve open detection device 30, an AND gate 32, and a counter 33.

The valve opening device 30 detects the time during which the valve of the injector is open and sends out an electric signal. For example, an output signal a as shown in FIG.
give. Of this signal a, a portion a1 is a portion where the valve opening time is long when the engine is running, and a portion a2 is a portion that occurs when the engine brake is applied. Note that instead of the valve open detection device 30, a fuel flow meter provided in the fuel supply pipe may be used.

Output signal a of device 30 is ANDed with clock signal CK in AND gate 32. This clock signal CK has a much higher frequency than the valve opening signal a, as shown in FIG. 3b, and the output of the AND gate 32, and therefore the input of the counter 33, is as shown in FIG. 3c. It looks like signal c.

The counter 33 uses this signal Hc as a counter signal to send the consumption signal e to the selection circuit 12 in the form of a BCD signal.
Send to.

The selection circuit 12 includes two remaining fuel level detection devices 1
Display circuit 1 depending on which signal among 0 and 11
3, and includes various logical operations.

That is, when the first remaining fuel amount detecting device 10 detects that the remaining fuel amount is below a predetermined amount, the selection circuit 12 automatically sets the gauge signal g to "0", and based on this signal, the selection circuit 12 sets the gauge signal g to "0". This circuit starts up the remaining fuel amount detection device 11 of No. 2 for the first time.

Therefore, the second remaining fuel amount detection device 11 performs a calculation to subtract the amount of fuel used from this predetermined amount.
It detects the remaining amount.

In this case, the starting point of the calculation is clearer (even if the calculation starts from when the tank is full, we do not know exactly how many liters a full tank is), and the quantity is smaller, making it more accurate. When reading is required, electronic methods are more accurate and more practical, and the circuit configuration can be simplified, leading to cost reductions.

Note that the predetermined amount is a scarce amount that requires refueling at an early opportunity, and is set to 15 for a tank of 60, for example.

Therefore, in the case of this embodiment, when the remaining fuel amount is more than the predetermined amount (15), since accurate recognition of the remaining fuel amount is not so required, the first fuel remaining amount of the commonly used gauge type is used. The remaining amount is detected by the accuracy of the amount detecting device 10. Therefore, at this time, although it is affected by the inclination of the vehicle body, the remaining amount can be displayed normally even if the tank is less than full.

Next, when the fuel level becomes less than 15, priority is given to the consumption signal e from the second remaining fuel amount detection device 11.

That is, when the remaining fuel amount becomes low and the remaining travel distance becomes an important issue, the second remaining fuel amount detection device 11 accurately detects the remaining fuel amount.

In addition, when refueling is performed after the remaining amount has decreased in this way, the first remaining fuel amount detection device 10 normally exceeds the predetermined amount (15) even if the refueling is less than full. The display is switched to the output g, and no erroneous display occurs.

By the way, the selection circuit 12 outputs a signal indicating that the ignition switch is turned on after the engine is turned off, or that the lid for injecting fuel into the fuel tank is opened.
If such an operation is detected in the middle of a state in which consumption signal e is detected with IGN and LID and priority is given, priority is given to signal g.

In other words, in order to cope with the erroneous display caused by mid-way refueling or fuel removal while parking, which is a drawback of the second remaining fuel amount detection device 11, within a range where the remaining amount does not exceed a predetermined amount, refueling is performed when the vehicle is parked or when the vehicle is refueled. If the remaining fuel amount is 15 or more or less than 15, the display is returned to the first remaining fuel amount detection device 10.

Note that the signals IGN and LID are provided for a limited time using a timer.

With the above configuration, even if some abnormality occurs during the process, appropriate display based on the gauge signal g is possible. For this reason, it is also desirable to separately provide a display warning that the display is based on the signal g.

The display circuit 13 displays the remaining amount of fuel based on the aforementioned signals g and e, and various display means such as a segment display using a fluorescent tube can be used. Alternatively, CRT, LED, etc. may be used as the display means. It goes without saying that the circuit 13 can take various configurations depending on the display means.

(Effects of the Invention) As described above, in the present invention, the second remaining fuel amount detection device detects the remaining amount of fuel by subtracting the amount of fuel used from a predetermined amount, and serves as the source of the subtraction. Since the numbers were not rewritten,
The configuration of the electronic circuit can be simplified to reduce costs, and at the same time, when the second remaining fuel amount detection device is activated, it is affected by the poor start-up of the first remaining fuel amount detection device. This has the effect of being able to display information with a high degree of accuracy, and by making this predetermined amount a scarce amount that requires refueling at an early opportunity, the remaining fuel amount will be reduced to this predetermined amount if refueling is done midway. Since the display is switched to the display by the first remaining fuel amount indicator when the fuel level is exceeded, it is possible to deal with the problem without displaying an incorrect amount.

Moreover, once the remaining fuel amount becomes low, the second remaining fuel amount detection device will display the result by subtraction.
It is possible to obtain an effect that highly accurate display can be performed without displaying a display that gives a sense of distrust, such as the display remaining amount increasing during the drive.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, FIG. 2 is a system diagram showing main parts of the embodiment, and FIG. 3 is a timing chart showing signals in each part of the system diagram of the embodiment. DESCRIPTION OF SYMBOLS 10... First fuel remaining amount detection device, 11... Second fuel remaining amount detection device, 12... Selection circuit, 13... Display circuit.

Claims (1)

[Claims] 1. A first remaining fuel amount detection device that detects the remaining amount of fuel based on an electric signal given by a gauge installed in the fuel tank; and this first remaining fuel amount detection device. When the detected remaining amount reaches a predetermined amount, which is a scarce amount that requires early refueling, the engine is activated, detects the amount of fuel used by the engine, and uses an electronic circuit to subtract the amount of fuel used from the predetermined amount to determine the remaining fuel amount. a second remaining fuel amount detection device that executes a calculation to obtain the remaining fuel amount; Displays the remaining amount, while
a selection circuit that displays the remaining fuel amount based on the output signal of the second remaining fuel amount detecting device when the remaining fuel amount detected by the first remaining fuel amount detecting device becomes equal to or less than the predetermined amount;
A fuel remaining amount display device for an automobile, comprising: