JPH0419051B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a remaining fuel amount detection device for a vehicle.

Conventional devices of this type detect the remaining amount of fuel in the fuel tank based on a signal from a sender that detects the liquid level of fuel in the fuel tank, and also detect the amount of fuel remaining in the fuel tank based on the fuel injection signal from the fuel injection control device. The amount of fuel consumed is detected and the amount of fuel remaining at each instant is determined by subtracting the amount of fuel consumed from the remaining amount of fuel initially detected by the signal from the sender or from the remaining amount of fuel determined by calculation.

By doing this, even if the liquid level in the fuel tank fluctuates while the engine is running or the vehicle is running, the remaining fuel amount data obtained will increase along the way as the liquid level fluctuates. Regardless of fluctuations in liquid level,
It is possible to obtain fuel remaining amount data that decreases sequentially as the engine is operated. In other words, the fuel remaining amount data detected by the sender signal is directly affected by fluid level fluctuations, but the fuel consumption data determined from the fuel injection signal is independent of the fluid level. Therefore, by subtracting the fuel consumption amount from the remaining fuel amount detected when there is no fluid level fluctuation, highly reliable fuel remaining amount data can be obtained.

However, the fuel consumption data has a problem in that an error occurs between the data and the actual fuel consumption due to fluctuations in fuel temperature and fuel injection pressure. If an error occurs in the fuel consumption data, an error will naturally occur in the calculated remaining amount of fuel.

In view of such conventional problems, an object of the present invention is to correct the remaining fuel amount detected by the sender when an error occurs in the remaining fuel amount calculated based on the fuel consumption amount. By using the output as is, accurate fuel remaining amount data with few errors can be obtained.

The first configuration of the present invention to achieve this purpose is as follows.
This will be explained using figures.

The remaining fuel amount detection means detects the remaining amount of fuel in the fuel tank based on a signal from a sender that detects the liquid level of fuel in the fuel tank, and the fuel consumption amount detection means detects the amount of fuel supplied to the engine. Detects fuel consumption based on the amount.

The remaining fuel amount calculation means calculates the fuel consumption detected by the fuel consumption amount detection means from the remaining fuel amount initially detected by the remaining fuel amount detection means or the remaining fuel amount obtained by calculation. Determine the remaining fuel amount by subtracting the amount.

Further, the remaining fuel amount determining means determines whether the remaining fuel amount calculated by the remaining fuel amount calculation means has reached a predetermined value, and the error monitoring means determines whether the remaining fuel amount determined by the remaining fuel amount calculating means has reached a predetermined value. When it is determined that the fuel amount has reached a predetermined value, the remaining fuel amount calculated by the remaining fuel amount calculation means and the remaining fuel amount detected by the remaining fuel amount detection means are compared, and the difference between the two is determined. The presence or absence of an error is monitored based on whether the difference exceeds a predetermined range.

When the error monitoring means determines that there is an error, the remaining fuel amount calculation means directly outputs the remaining fuel amount detected by the remaining fuel amount detection means.

According to the present invention described above, when the remaining amount of fuel becomes low and becomes greatly influenced by errors, and errors accumulate in the fuel consumption data,
Although it is affected by changes in the liquid level in the fuel tank, the remaining fuel level is detected using the sender signal that accurately indicates the remaining fuel level, so accurate remaining fuel level data can be obtained and this data can be used. When the remaining fuel amount is displayed by using this, a highly reliable display can be made.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an electric circuit according to an embodiment of the present invention. The arithmetic circuit 1, which constitutes the main part of the present invention, inputs signals from various parts to determine the remaining fuel amount and displays it. A signal is output to a display 11 via a circuit 10. The input signal of the arithmetic circuit 1 is
These are signals from the A/D converter 3 and waveform shaping circuits 6 and 7. The A/D converter 3 receives the signal from the sender 2 that detects the level of fuel in the fuel tank, and converts it into a digital signal. Convert and output. Further, the waveform shaping circuit 6 shapes the waveform of the fuel injection signal from the fuel injection control device 4 and outputs the same, and the waveform shaping circuit 7 shapes the waveform of the ignition signal from the ignition control device 5 and outputs the same.

On the other hand, the drive circuit 10 receives a signal representing the remaining amount of fuel from the arithmetic circuit 1 and converts it into a signal for driving the display 11.

The constant voltage circuit 12 is connected to a battery 8 as a power source via an ignition switch 9, and supplies a constant voltage with no voltage fluctuation to the arithmetic circuit 1, the sender 2, the A/D converter 3, and the waveform shaping circuit 6. ,7
The display power supply circuit 13 is connected to the battery 8 via the ignition switch 9 to generate the voltage necessary for the display 11 and to supply the display 11 to the display 11.
It is intended to supply Further, the fuel injection control device 4 and the ignition control device 5 are connected to a battery 8 via an ignition switch 9.

The arithmetic circuit 1 consists of a digital computer, and its program contents are as shown in the flowchart of FIG.

Next, the operation will be explained along this flowchart.

When the program is started, registers in the computer are cleared and initialized in a step not shown, and then step 2
0, the output of the sender 2 is read from the A/D converter 3, and in step 21, the remaining fuel amount _F1 is calculated based on the output of the sender 2, and this is output to the drive circuit 10. Therefore, at this time, the remaining fuel amount _F1 is displayed based on the signal from the drive circuit 10. Note that the processes in steps 20 and 21 correspond to the remaining fuel amount detection means of the present invention.

Next, in step 22, it is determined whether the engine is in operation based on whether an ignition signal corresponding to a predetermined engine speed is generated from the waveform shaping circuit 7. When the engine is stopped and no ignition signal is generated from the ignition control device 5, no signal is output from the waveform shaping circuit 7, so a negative determination is made in step 22, and this signal is not output until the engine is in operation. It waits in step 22. The engine is in operation, and the waveform shaping circuit 7
When the ignition signal is supplied from the ignition control device 5 via the
Proceed to step 3.

In step 23, the fuel injection signal supplied from the fuel injection control device 4 via the waveform shaping circuit 6 is detected, and the pulse width τ of this signal and the period T of the fuel injection signal are read. In step 24, the period T
It is determined whether or not Tmax is greater than a predetermined value Tmax. The process of step 24 is to determine whether the fuel injection signal is generated within a predetermined time Tmax, and whether the fuel injection signal is normally supplied from the fuel injection control device 4 via the waveform shaping circuit 6. This is to determine whether or not. Now, if the fuel injection signal is normally supplied and the period T is smaller than Tmax, an affirmative judgment is made in step 24 and the process proceeds to step 26. When the signal is not normally supplied, the period T is larger than Tmax, so a negative determination is made in step 24.
Proceed to step 25. In fact, Tmax is
It is set to 5-10 minutes.

If the fuel injection signal is normally supplied, step 26
When the process proceeds to step 26, the fuel consumption amount is calculated by integrating the pulse width τ of the fuel injection signal. This step 26 and the process of step 23 described above correspond to the fuel consumption amount detection means of the present invention. Next, in step 27, step 2
The fuel consumption calculated in step 26 is subtracted from the remaining fuel amount F ₁ calculated in step 1 to obtain the remaining fuel amount F ₂ at that time. The remaining fuel amount data F ₂ determined here is output to the drive circuit 10 and displayed on the display 11. Additionally, the remaining fuel amount data _F2 obtained in step 27 is stored in the computer.
It is stored in RAM or a register and used as data for the next calculation.

When the fuel injection signal is not normally supplied and the process proceeds to step 25, as a countermeasure against an abnormality, in step 25, the signal from the sender 2 is read through the A/D converter 3 as in step 20.
Next, in step 28, the remaining fuel amount _F3 is calculated based on the signal from the sender 2, as in step 21, and is output to the drive circuit 10. Step 28
When the process is completed, the process returns to step 22 and the process is repeated.

When the remaining fuel amount F ₂ is calculated in step 27 as described above, it is determined in step 29 whether the remaining fuel amount F ₂ has become less than a predetermined value Ft (for example, 10 to 15). . If the calculated remaining fuel amount F ₂ is greater than the predetermined value Ft, a negative determination is made in step 29 and the process returns to step 22 to repeat the process from step 22 onwards, so that the remaining fuel amount F ₂ is greater than the predetermined value Ft. Less than Ft Step 29
If an affirmative determination is made, the process proceeds to step 30. Note that the process of step 29 corresponds to the remaining fuel amount determining means of the present invention.

In step 30, similarly to steps 20 and 25, the signal from the sender 2 is read through the A/D converter 3, and in step 31, the signal from the sender 2 is read in through the A/D converter 3.
The remaining fuel amount _F4 is calculated based on the signal read in. Note that the processing in steps 30 and 31 and the processing in steps 25 and 28 described above correspond to the remaining fuel amount detection means of the present invention, similar to the processing in steps 20 and 21. Next, in step 32, the difference between the remaining fuel amount _F2 calculated in step 27 and the remaining fuel amount _F4 calculated in step 31, that is, the actual fuel amount calculated using the fuel consumption amount is calculated. Find the error E for the remaining amount and proceed to step 3.
In step 3, it is determined whether the error E is within a predetermined range K or not. As a result of accurate fuel consumption detection,
If the error E is small and step 33 is answered in the affirmative, the process returns to step 22 and the remaining fuel amount is calculated in the same manner as before the remaining fuel amount became less than the predetermined value Ft, and the fuel temperature and If the fuel consumption cannot be accurately detected due to the influence of fluctuations in fuel injection pressure, and the error E increases and a negative determination is made in step 33, the process proceeds to step 34, in which the calculation circuit 1 changes the drive circuit. 10 is switched from _F2 to _F4 . In other words,
The system stops displaying the remaining fuel amount data _F2 , which has many detection errors, and starts displaying the remaining fuel amount data _F4 , which has some fluctuations but is accurate.
Note that the processing in steps 32 and 33 corresponds to the error monitoring means of the present invention, and the processing in step 2
The processes 7 and 34 correspond to the remaining fuel amount calculation means of the present invention.

In this way, while it is hardly affected by slight detection errors, that is, while the remaining fuel amount is relatively large, the remaining fuel amount is calculated using the fuel consumption detected in steps 23 and 26, and the remaining fuel amount is calculated. The data is not affected by fluctuations in the liquid level in the fuel tank and gradually decreases as the engine operates, and when the data becomes significantly affected by detection errors, that is, when the amount of fuel remaining is relatively low. When the amount of fuel is exhausted, it is checked in steps 32 and 33 whether there is an error exceeding the allowable range in the remaining fuel amount data obtained using the fuel consumption amount, and if there is an error exceeding the allowable range,
The remaining fuel amount signal outputted to the display 11 is made to be the remaining fuel amount detected in steps 30 and 31, which is free from error and is influenced by fluctuations in the liquid level in the fuel tank. Therefore, stable display without fluctuation can be performed until the remaining fuel amount becomes low, and accurate display can be performed after the remaining fuel amount becomes low.

Although one embodiment of the present invention has been described above,
The present invention is not limited to this example, but includes various embodiments within the scope of the claims, some of which are listed below.

(1) The detection result of the remaining fuel amount can be used not only as a display but also as an input signal to other control devices.

(2) The arithmetic circuit can be constructed from a dedicated hardware circuit instead of a computer.

(3) When calculating the remaining fuel amount by subtracting the fuel consumption amount from the remaining fuel amount data, the remaining fuel amount initially detected by the sender signal should be memorized, and the fuel consumption amount detected from time to time should be stored. It is also possible to calculate the amount of fuel remaining at each instant by adding up the amount of fuel and subtracting the amount of fuel consumption that has been accumulated from the stored amount of remaining fuel.

(4) Detection of fuel consumption can also be performed by a signal from a flow meter installed in the path that supplies fuel to the engine.

[Brief explanation of drawings]

Fig. 1 is a complaint correspondence diagram, Fig. 2 is a block diagram showing an electric circuit of an embodiment of the present invention, and Fig. 3 is a flowchart showing the program contents of a computer adopted in an embodiment. . 1...Arithmetic circuit, 2...Sender, 3...A/D
Converter, 4... Fuel injection control device, 5... Ignition control device, 6, 7... Waveform shaping circuit, 8... Battery, 9... Ignition switch, 10...
... Drive circuit, 11 ... Display device, 12 ... Constant voltage circuit, 13 ... Power supply circuit for display device.

Claims (1)

[Claims] 1 Fuel remaining amount detection means detects the remaining amount of fuel in the fuel tank based on a signal from a sender that detects the level of fuel in the fuel tank, and fuel consumption is determined based on the amount of fuel supplied to the engine. The fuel consumption amount detected by the fuel consumption amount detection means from the fuel consumption amount detection means to be detected, the amount of fuel initially detected by the remaining fuel amount detection means, or the amount of remaining fuel determined by calculation. In the remaining fuel amount detection device, the remaining fuel amount detection device includes a remaining fuel amount calculating means for calculating the remaining fuel amount by subtracting the remaining amount of fuel. When the remaining fuel amount determining means and the remaining fuel amount determining means determine that the remaining fuel amount has reached a predetermined value, the remaining fuel amount calculated by the remaining fuel amount calculating means and the remaining fuel amount detecting means are calculated. and error monitoring means for comparing the detected remaining fuel amount and monitoring the presence or absence of an error depending on whether the difference between the two exceeds a predetermined range, and the remaining fuel amount calculating means 1. A fuel remaining amount detecting device characterized in that, if an error is detected by the means, the remaining fuel amount detected by the remaining fuel amount detecting means is output as is.