JPH0324974B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a fuel detection device, and in particular to a main sensor that detects the remaining amount of fuel in the entire fuel tank, and a device that accurately detects the remaining amount when the remaining amount is low. The present invention relates to a fuel detection device equipped with a child sensor.

[Technical background of the invention and its problems]

For example, an automobile fuel meter disclosed in Japanese Utility Model Application Publication No. 16469/1983 is a fuel detection device that calculates and displays one piece of data using two or more sensors for one detected object, that is, the remaining amount of fuel. There is.
This sensor consists of a float floating on the liquid surface to constantly detect the remaining amount of fuel in the fuel tank and a sliding resistance that converts the displacement of this float into an electrical signal, and a main sensor to detect the remaining amount when the fuel is low. It is equipped with a secondary sensor consisting of a float and a sliding resistor that is more accurate than the sliding resistor, and can accurately display the remaining amount of fuel when the fuel is running low.

By the way, since the sliding resistance of the parent sensor requires measuring the capacity of the entire fuel tank and has a large range, the accuracy is poor and the detected value varies depending on the sensor. On the other hand, since the sliding resistance of the child sensor has a small range, it is accurate and there is almost no variation in detected values depending on the sensor. Therefore, the detection values of the parent sensor and the child sensor do not necessarily match. In this prior art, where the remaining fuel amount is displayed using an analog system between the main meter and the sub-meter, the driver does not pay much attention to the difference in detected values due to parallax.

However, in devices that digitally display the remaining fuel level, the display is generally switched from the parent sensor to the detected value of the child sensor until the specified remaining amount (for example, 4) is reached. Due to variations in the sliding resistance of the two sensors, the detected values of the two sensors may not match, and the display suddenly changes from 6 (the value displayed by the parent sensor) to 4 when switching.
(the value displayed by the secondary sensor) changes discontinuously, giving the driver a sense of discomfort. Furthermore, in order to eliminate such discontinuous changes, the accuracy of the parent sensor must be improved to eliminate variations, which makes the parent sensor expensive and time-consuming.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and when the remaining fuel amount is detected by two or more sensors and displayed by switching, the level difference between the detected values by the two sensors is removed in stages, It is an object of the present invention to provide a fuel detection device that does not make the driver aware of this level difference and does not give a sense of discomfort by updating the display smoothly.

(Structure of the Invention) The structure of the present invention to achieve the above object includes a main sensor that detects the remaining amount of fuel in the entire fuel tank, and a detection range smaller than this main sensor that detects the remaining amount when the remaining fuel amount is low. In the fuel detection device, the remaining amount of fuel is detected by a child sensor, and the detected value of one is displayed by switching between the parent sensor and the child sensor, when the display is switched between the parent sensor and the child sensor. The present invention is characterized in that it includes arithmetic means that detects a level difference between detected values and corrects this level difference in stages, and updates the display from one detected value to the other detected value in stages.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a block diagram showing one embodiment of a fuel detection device according to the present invention. In the figure, 1 is a fuel tank, and the amount of water in the fuel tank 1 detected by, for example, a float-type liquid level sensor 2, which constitutes a parent sensor for measuring the remaining amount of fuel in the fuel tank 1 as a whole. The liquid level displacement is converted into an electrical signal by the sliding resistance. The liquid level height information converted into an electric signal is passed through a delay circuit 3, for example, to prevent flickering caused by irregular fluctuations in the liquid level, and then converted into a digital signal by an A/D converter 4, which is then sent to a control circuit 5. Output to. A fuel consumption detection circuit 6 is provided below the fuel tank 1 and is connected to a fuel injection device that supplies fuel to the internal combustion engine of the vehicle.
outputs a consumed fuel pulse signal proportional to the amount of fuel output from the fuel flow sensor S to the control circuit 5. Liquid level sensor 2 and fuel consumption detection circuit 6
The E point sensor 7, which is a thermistor or reed switch, for detecting the specified remaining fuel amount, detects that the liquid level in the fuel tank 1 has fallen to a position corresponding to the specified remaining amount. , Due to this detection, the E point signal generation circuit 8 becomes "H"
Alternatively, an "L" point E signal is output to the control circuit 5. The fuel flow rate sensor S and the fuel consumption detection circuit 6 constitute a child sensor whose detection range is smaller than that of the parent sensor.

The control circuit 5 includes a first calculation means 9 that converts the liquid level displacement measured by the liquid level sensor 2 into the remaining fuel amount Vr;
The consumption amount R detected by the fuel consumption detection circuit 6 from the specified remaining amount L detected by the E point sensor 7
Accurate fuel level when low by subtracting
When there is a level difference between the second calculation means 10 that calculates Vx and the fuel remaining amount Vr of the first calculation means 9 when the E point sensor 7 is ON and the specified remaining amount L, this level difference is and a CPU 12 that controls the first and second calculation means 9 and 10 and the calculation means 11.
The display circuit 13 displays the remaining amount of fuel calculated by the control circuit 5.

The operation of the control circuit 5 of the apparatus of the present invention constructed as described above will be described in detail with reference to the flowchart shown in FIG.

In response to a fuel injection device (not shown) supplying fuel in the fuel tank 1 to the internal combustion engine, the fuel tank 1
This displacement is detected by the liquid level sensor 2, which is a parent sensor, and is output to the control circuit 5 as liquid level height information. In STEP 1, the E point sensor 7 detects the specified remaining amount L for switching and displaying the remaining fuel amount Vr detected by the parent sensor and child sensor, and the liquid level is set to the specified remaining amount L.
It is determined whether the value is lower or higher. This E point sensor 7 detects when the liquid level decreases and reaches the specified remaining amount L.
If it is OFF, the liquid level sensor 2 is determined by the first calculation means 9 in STEP 2.
The remaining fuel amount Vr is calculated based on. Note that the accuracy of the liquid level sensor 2 is lower than the accuracy of the E point sensor 7, so even if the E point sensor 7 is OFF, the remaining fuel amount Vr based on the liquid level sensor 2 will be less than the specified remaining amount L. Therefore, in STEP 3, the specified remaining amount L and the remaining fuel amount Vr are compared in magnitude.
If Vr≦L, the actual remaining fuel amount is greater than the specified remaining amount L, but it is determined that the calculated remaining fuel amount Vr is less than the specified remaining amount L due to the poor accuracy of the liquid level sensor 2, and in STEP 4 The remaining amount L is adopted as the display value Va displayed on the display circuit 13. If Vr>L in STEP 3, the remaining fuel amount Vr is adopted as the display value Va in STEP 5.

On the other hand, when the E point sensor 7 turns ON in STEP 1, it is determined for the first time whether the E point sensor 7 turns ON (STEP 6). When the E point sensor 7 turns ON,
When the remaining amount of fuel decreases, the remaining fuel amount Vx, which is detected with more accuracy based on the fuel consumption amount detection circuit 6 which is a child sensor, is adopted as the display value Va.
When the E point sensor 7 turns ON for the first time, the remaining fuel amount Vx becomes the specified remaining amount L in STEP7. Also,
If the E point sensor 7 is ON in the previous display, in STEP 8, the second calculation means 10 calculates the total fuel consumption from the time the E point sensor 7 turned ON to the present time R=R'・t( R' is the consumption amount per unit time, and t is the elapsed time), and the remaining fuel amount Vx is calculated as Vx=L- _o 〓 ^t=0 R.
In STEP 9, the E point sensor 7 determines whether there is a level difference when switching between the display of the remaining fuel amount by the parent sensor and the child sensor. In other words, if the remaining fuel amount Vx is less than the previous displayed value Va'. ,
In STEP10, the display value Va is calculated by the calculation means 11.
is Va=Vr'-K・(t/T) (where, Vr' is the remaining amount of fuel based on the liquid level sensor 2 at the time of switching, t is the elapsed time from the time of switching to the present, and T is the forced display update unit time) ,K
is the forced display update unit fuel, and (t/T) is an integer. ) becomes. (t/T) is a step function that is an integer, so if there is a level difference in the remaining fuel level between the parent sensor and the child sensor, this level difference is displayed and updated in stages as shown in Figure 4B. removed.
Incidentally, FIG. 4A is a display by a conventional device. Also, if Vx≧Va′ in STEP9, it is assumed that the above level difference has been removed, and the displayed value Va
The remaining fuel amount Vx is displayed as (STEP 11). In this way, various conditions are calculated by the control circuit 5, and a display value Va corresponding to each condition is displayed on the display circuit 13.

In particular, if the forced display update unit time T is set to a long time on the order of minutes, even in such a gradual forced update display, the display will give the impression that it is due to actual fuel consumption, and the driver will not notice anything strange. It doesn't give you any kind of feeling.

In this way, the fuel detection device has a main sensor that detects the remaining amount of fuel in the entire fuel tank, and a child sensor that more accurately detects the remaining fuel amount when the remaining fuel amount is low, and the detection values of both sensors are adjusted to the same level. If there is a difference, the display is updated step by step because it is equipped with calculation means that corrects the level difference step by step. Unlike conventional devices, the displayed value suddenly changes due to switching, which causes a sense of discomfort to the driver. There will be no more to give.

This method of correcting and removing level differences in stages is particularly effective when the display format of the display circuit is digital, but as shown in Figure 5, many segments are arranged to increase resolution. The bar graph type is also effective when one scale indicates the amount of fuel remaining in the entire fuel tank, and the other scale indicates the remaining amount of fuel when the fuel is running low.

〔Effect of the invention〕

As detailed above, according to the present invention, the remaining fuel amount is detected by two or more detection means, and when there is a level difference between the detected values, the calculation means is provided to correct the level difference in stages, By displaying the detected value in stages from one detected value to the other, it prevents the detected value from suddenly changing discontinuously and causing a sense of discomfort to the driver, and eliminates the level difference between the detected values in stages. However, by updating the display smoothly, it is possible to provide a fuel detection device that does not make the driver aware of this level difference.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a control circuit, FIG. 3 is a flowchart showing the operation of the control circuit, and FIG. 4A is a graph showing defects in the conventional device. FIG. 4B is a graph modified according to the present invention, and FIG. 5 is an explanatory diagram showing one display form according to the present invention. 2...Liquid level sensor (parent sensor), 5...Control circuit, 6...Fuel consumption detection circuit (child sensor), 7
...E point sensor, 8...E point signal generation circuit, 11...calculating means, S...fuel flow rate sensor (child sensor).

Claims (1)

[Claims] 1. The remaining amount of fuel is detected by a parent sensor that detects the amount of fuel remaining in the entire fuel tank, and a child sensor that has a smaller detection range than this parent sensor and that detects the remaining amount when the remaining fuel amount is low. In a fuel detection device configured to display a detection value of one of the child sensors by switching between them, a level difference between the detection values of the parent sensor and the child sensor at the time of display switching is detected, and this level difference is gradually adjusted. A fuel detection device comprising a computation means for correction and updating a display stepwise from one detected value to another detected value.