JPH08218962A - Fuel tank fuel remaining quantity detector - Google Patents

Abstract

PURPOSE: To recognize a quantitative remaining fuel quantity without respect to a shape of a fuel tank or the number of tanks by computing a real fuel remaining quantity on the basis of an indirectly detected fuel remaining quantity and indicating the fuel remaining quantity on the basis of the computed result. CONSTITUTION: A fuel remain sensor 100 outputs an output value indicating a liquid level of fuel stored in a fuel tank 11 so as to input it to a control unit 7. A fuel quantity inside the fuel tank 11 and the output value of the remain sensor 100 are evaluated previously, and the result is set in a table, and then, according to the output of the remain sensor 100, the table is retrieved, and subsequently, a real fuel remaining quantity is computed. When the computed value is the predetermined threshold value, which is previously evaluated, or less and it is determined that a horizontal degree of a fuel level is maintained, a weighted average between a read value of the fuel remaining quantity sensor and the previous read value is computed, so that a stable fuel remaining quantity is computed. This computed result is outputted to a fuel remaining quantity display panel in an instrument panel, and a quantitative fuel remaining quantity is informed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a residual quantity display method according to a residual fuel quantity in a fuel tank for holding fuel to be supplied to an internal combustion engine, and an internal combustion engine control according to the residual quantity.

[0002]

2. Description of the Related Art Generally, the residual quantity in a fuel tank is displayed by detecting the residual quantity by a residual fuel quantity sensor mounted in the fuel tank and displaying the residual quantity according to the sensor output value. With this display, the driver can recognize the residual fuel amount in the fuel tank.

[0003]

However, in the above-described fuel residual quantity detecting device, there are many cases in which only the liquid level in the fuel tank is detected and used as the residual fuel quantity, and depending on the shape of the fuel tank. However, since the quantitative fuel amount is not detected, even in the multi-tank fuel tank, the driver cannot accurately recognize the residual fuel amount. In addition, according to the residual fuel amount detection value, control of the internal combustion engine,
For example, it is not used as a control amount parameter for controlling the amount of air-fuel mixture (hereinafter referred to as purge amount) supplied from the canister to the internal combustion engine. Therefore, due to the residual fuel amount, it is not possible to perform the optimum purge amount control according to the amount of fuel vapor generated in the fuel tank (hereinafter referred to as vapor amount). The present invention addresses the above-described problems and allows a driver to recognize a quantitative residual fuel amount regardless of the shape of the fuel tank and the number of tanks, and a fuel injection amount control device according to the residual fuel amount. And to provide a canister purge control device.

[0004]

SUMMARY OF THE INVENTION A fuel residual amount detecting device for achieving the above object is a sensor for indirectly detecting the residual fuel amount in a fuel tank, and a true residual amount based on the sensor output value. A means for calculating a fuel amount, a means for displaying the residual fuel amount, a means for storing the fuel amount, a means for calculating a fuel injection amount based on the fuel residual amount, and a means for calculating the fuel residual amount. And a means for calculating the canister purge control amount.

[0005]

With the above arrangement, the residual fuel amount retained in the fuel tank can be linearly detected, and the driver is informed of the quantitative residual fuel amount. Further, the control of the fuel injection amount and the canister purge amount of the internal combustion engine is corrected by using the residual fuel amount detecting means.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments according to the present invention will be described below with reference to the drawings.

FIG. 2 shows an example of an internal combustion engine applied to the present invention. In the figure, the fuel to be supplied to the internal combustion engine is stored in a fuel tank 11, which is sucked and pressurized by a fuel pump 10. Then, the fuel damper 22, the fuel filter 2
3, a fuel injection valve (injector) 5, and a fuel pressure regulator 12 are supplied to the fuel system in which they are piped. Also,
The fuel residual sensor 100 outputs an output value representing the liquid level height of the fuel stored in the fuel tank and is input to the control unit 7.

On the other hand, the air to be taken in by the internal combustion engine is taken in from the inlet of the air cleaner 1, passes through the throttle valve body 4 which controls the amount of intake air, and enters the collector 20. Then, the intake air is distributed to each intake pipe 21 connected to each cylinder of the internal combustion engine 18 and guided to each cylinder.

The air flow meter 2 outputs a signal indicating the air flow rate, and the water temperature sensor 13 outputs a signal indicating the cooling water temperature, which is input to the control unit 7.

Further, the throttle valve body 4 has a throttle valve 35.
A throttle sensor 24 for detecting the opening degree of is attached, and its output is also input to the control unit 7.

Numeral 9 is a canister for temporarily adsorbing fuel vapor (vapor) generated in the fuel tank 11 and purging valve 8
By this, a desired amount is purged according to the operating state.

The main part of the control unit 7 is shown in FIG.
A driver circuit 901 for converting a small signal from various sensors into a large signal for driving an actuator as shown in FIG. 1, and an interface (input / output) circuit 90 for converting an input / output signal into an analog-digital signal capable of performing digital arithmetic processing.
2, an arithmetic circuit 903 having a microcomputer for performing digital arithmetic processing or an arithmetic circuit equivalent thereto
The arithmetic circuit 903 includes two types of memories, a ROM 904 and a volatile RAM 905, which store constants and variables used for arithmetic processing of the arithmetic circuit, and a program, and a backup circuit 906 which holds the contents of the volatile RAM 905. In the illustrated example, signals from various sensors such as an air flow meter 2, a throttle valve opening sensor 24, an oxygen concentration sensor 15, and a crank angle sensor that detect an operating state of a fuel tank residual amount sensor and an internal combustion engine are input. As a result of the calculation, various control signals calculated as a result of the calculation are output, and a predetermined control signal is supplied to the instrument display and the fuel injection valve 5 and the purge valve 8 to display the residual fuel amount, It performs fuel injection control, canister purge control, etc.

FIG. 8 shows a general example of detection in the case of a residual amount sensor for detecting the liquid level of the stored fuel in the fuel tank. ΔQ is the fuel capacity corresponding to the liquid level difference Δt1
1, and assuming that the fuel capacity corresponding to the liquid level difference Δt2 at a portion different from Δt1 is ΔQ2, ΔQ1 ≠ ΔQ2 even if Δt1 = Δt2 due to the shape of the fuel tank, and the output of the liquid level sensor is accurate. Does not indicate residual fuel quantity.

In the internal combustion engine having such a configuration, the following processing is performed in order to accurately grasp and display the residual fuel amount.

FIG. 1 shows an example of a fuel tank residual fuel amount detection block of the present invention. Block 201
Then, the signal of the ignition switch of the internal combustion engine is fetched, it is judged whether the signal is ON (energized state) or OFF (non-energized state), and if ON, the output value of the residual fuel amount sensor is read as in block 202.

Therefore, in block 203, in order to calculate the true residual fuel amount FURE according to the shape of the fuel tank, the fuel amount in the fuel tank and the residual amount sensor output value are evaluated in advance, and the results are stored in the FURE table. The true residual fuel amount FURE can be calculated by setting and searching the table according to the residual amount sensor output.

In block 204, the output value FUREne read in block 203 after the ignition switch is turned on.
The difference ΔFURE between w and the memory backup value FUREold, which is retained even after the ignition switch is turned off, is calculated from w and the value immediately before the ignition switch is turned off. This ΔFUR
It is determined whether the E value is greater than or equal to the predetermined value DFURE. Thereby, it is determined whether the fuel is newly supplied to the fuel tank. If the memory of the backup value is erased due to the attachment / detachment of the battery, FUREold = 0 may be set. If it is determined that fuel has been newly supplied to the fuel tank, the property of the fuel supplied to the internal combustion engine may differ depending on the supplied fuel. ), And if the engine is rotating, a block 206 calculates a fuel injection amount according to the operating state of the internal combustion engine. Here, it is necessary to change the fuel injection amount depending on the fuel property, and to control the fuel injection amount so as to increase the fuel injection amount for heavy fuel and decrease the fuel injection amount for light fuel. To do. A detailed example of the fuel property correspondence control based on the ΔFURE value will be described later (FIG. 5). Next, in the case of a residual fuel amount sensor that detects the liquid level of the fuel in the fuel tank, the level of the fuel liquid level is lost due to running conditions (for example, during acceleration) of the vehicle equipped with the fuel tank, and It becomes impossible to detect a sufficient residual fuel amount. Therefore, when it is detected that the fuel liquid level is impaired, the residual fuel amount detection update may be canceled and the value immediately before the liquid level is impaired may be held. An example of the control flow is shown below.

First, in block 207, it is determined whether the level of the fuel liquid level is impaired, that is, whether the vehicle is accelerating, decelerating, or turning. For the acceleration and deceleration, the rotational fluctuation ΔNE of the internal combustion engine for a predetermined time, or the speed fluctuation ΔVSP of the vehicle for a predetermined time, and the steering angle may be read for the vehicle turning. In addition, an acceleration sensor (G
When a sensor is attached, the G sensor output value may be read. Further, the level of the fuel liquid level is impaired not only when the vehicle is accelerated or decelerated but also when running on a gradient. Therefore, the gradient of the vehicle may be estimated from the rotational speed of the internal combustion engine, the gear position of the transmission, and the load of the internal combustion engine. If it is determined that the value calculated in block 207 is equal to or less than the predetermined threshold value evaluated in advance and the fuel level is maintained, the residual fuel amount is calculated in block 208.
The residual fuel amount is that the liquid level is slightly wavy due to vehicle vibration, and does not change rapidly while the vehicle is running.
A stable residual fuel amount (IFURE) can be detected by calculating a weighted average of the residual fuel amount sensor reading value (FUREnew) and the previous reading value (FUREold) as shown in the following equation (1).

IFURE = FUREnew × x + FUREold × (1-x) (1) The IFURE calculation result 209 is output to the residual fuel amount display panel of the instrument panel as shown in FIG. 4 to quantitatively inform the driver. It is possible to inform the remaining amount of fuel. Further, as a method of obtaining the same effect, a method of limiting the change in the residual fuel amount in a predetermined time from the amount of fuel supplied to the internal combustion engine for a predetermined time is also effective.

In addition, the residual fuel amount may be informed in a quantitative manner by digital display on the residual fuel amount display panel.

FIG. 3 shows an example of a fuel tank residual amount display evaluation result according to the present invention. The conventional residual fuel amount display method (B diagram in the figure) does not output a quantitative residual fuel amount due to the influence of the shape of the fuel tank, whereas the evaluation result according to the present invention (A in the figure). It can be seen that the graph) is proportional to the quantitative residual fuel amount.

Next, FIG. 5 shows an example of a general flow for controlling the fuel injection amount of the internal combustion engine using the residual fuel amount detection result according to the present invention. In block 501, the difference Δ between the FURE value and the backup value when the ignition switch is ON
When FURE becomes equal to or greater than the predetermined value DFURE1, it is determined that the fuel property has changed due to the supplied fuel as described above. In block 502, the fuel property determination flag, which has been previously learned through the determination, is cleared (the fuel property is determined to be the standard specification).
In block 503, the fuel injection amount calculation corresponding to the fuel property based on block 502 is performed. In block 504, the fuel property is determined again by a predetermined fuel property determination calculation.

Next, FIG. 6 shows an example of a general flowchart for controlling the canister purge amount by using the residual fuel amount detection result according to the present invention. The mixing ratio of the purged air-fuel mixture that once adsorbs the vapor generated in the fuel tank and purges it into the internal combustion engine depends on the vapor adsorption amount in the canister. Further, the adsorption amount on the canister depends on the fuel temperature, the fuel property, and the fuel storage amount of the fuel in the fuel tank.
Therefore, the canister purge mixture ratio can be estimated by quantitatively detecting the stored fuel amount in the fuel tank (the purge mixture ratio becomes richer as the fuel amount in the fuel tank increases). Therefore, in block 601, the difference ΔFURE between the FURE value and the backup value when the ignition switch is ON.
When is greater than or equal to the predetermined value DFURE2, it is determined that a large amount of vapor has been adsorbed in the canister. Even if the rich purge is performed in block 602, a predetermined (CAPAMIN) purge amount correction is performed so that the air-fuel ratio control of the internal combustion engine is not adversely affected. For example, when the fuel supplied to the fuel tank is increased, correction is performed to reduce the purge amount.

Next, FIG. 7 shows an example of a general flow chart of the condition for permitting failure diagnosis of the canister purge system using the detection result of the residual fuel amount according to the present invention. The failure diagnosis is performed by the pressure gradient in the canister pipe for a predetermined time, and if the pressure change exceeds a predetermined value, it is determined that there is a leak in the canister pipe, and it is determined that there is a failure Canister system Vapor is generated from the fuel tank In this case, even if the canister piping is normal, a pressure change similar to the above-mentioned piping leakage occurs, resulting in an erroneous diagnosis.

Therefore, in block 701, the residual fuel amount I
It is determined whether the FURE is equal to or more than the predetermined value DICAPA, and the DICAPA
In the case above, it is determined that a large amount of vapor is generated,
In block 702, the canister purge system failure diagnosis permission is canceled.

If the residual fuel change amount ΔFURE is obviously smaller than the fuel injection flow rate, it may be diagnosed that the fuel is leaking from the fuel tank.

[0027]

EFFECT OF THE INVENTION It is possible to calculate a quantitative residual fuel amount in the fuel tank corresponding to the shape of the fuel tank and display the quantitative residual fuel amount on the instrument panel to inform the driver. Further, the fuel property of the fuel injection amount of the internal combustion engine can be corrected according to the change in the residual fuel amount, and the canister purge amount control can be performed according to the residual fuel amount.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram according to an embodiment of the present invention.

FIG. 2 is a general flowchart for detecting a residual fuel amount according to the present invention.

FIG. 3 shows an example of the effect of the residual fuel amount detection of the present invention.

FIG. 4 is an example of a residual fuel amount display panel.

FIG. 5 shows an example of fuel injection amount control according to the residual fuel amount of the present invention.

FIG. 6 shows an example of a canister purge amount control according to the residual fuel amount of the present invention.

FIG. 7 shows an example of canister purge failure diagnosis conditions according to the residual fuel amount of the present invention.

FIG. 8 shows an example of a fuel tank shape and a liquid level sensor.

FIG. 9 is an internal circuit block of the residual fuel amount and internal combustion engine control device of the present invention.

[Explanation of symbols]

7 ... Control unit, 11 ... Fuel tank, 100
… Fuel residual sensor.

Claims (4)

[Claims] 1. A fuel tank for storing fuel to be supplied to an internal combustion engine, and means for indirectly detecting a residual amount of the fuel,
A means for preliminarily storing a correspondence relationship between the residual fuel amount in the fuel tank and a means for indirectly detecting the residual fuel amount in the fuel tank is provided. Based on the residual fuel amount detected by the detecting means And a residual fuel amount display device for displaying the residual fuel amount based on the residual fuel amount calculation result. 2. A fuel tank for storing fuel to be supplied to an internal combustion engine, and means for indirectly detecting the residual amount of the fuel,
A means for preliminarily storing a correspondence relationship between the residual fuel amount in the fuel tank and a means for indirectly detecting the residual fuel amount in the fuel tank is provided. Based on the residual fuel amount detected by the detecting means And a means for correcting the fuel injection amount control of the internal combustion engine on the basis of the fuel residual amount calculation result. 3. A fuel tank for storing fuel to be supplied to an internal combustion engine, and means for indirectly detecting the residual amount of the fuel,
A means for preliminarily storing a correspondence relationship between the residual fuel amount in the fuel tank and a means for indirectly detecting the residual fuel amount in the fuel tank is provided. Based on the residual fuel amount detected by the detecting means And a means for calculating the residual fuel amount, and correcting the canister purge amount control based on the residual fuel amount calculation result. 4. The engine according to claim 2, wherein the means for storing the calculated residual fuel amount even when the internal combustion engine is stopped is compared with the stored residual fuel amount when the internal combustion engine is started and the residual fuel amount when the internal combustion engine is started. A fuel tank residual fuel amount detection device characterized in that it is determined that refueling has been performed when the residual fuel amount at that time is larger than the stored residual fuel amount by a predetermined value or more.