JPH10184479A - Trouble diagnostic device of fuel level detecting means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent drop to the accuracy of diagnosis from occurring by installing a trouble detector which detects a failure of a fuel level detecting means on the basis of a comparative signal of a comparison means comparing an amount of integrated duel consumption and a fuel level variation. SOLUTION: A control unit 12 is set up in an internal combustion engine 1. This control unit 12 inputs each of output signals out of an air meter 5, a throttle sensor 6, an oxygen sensor 11 and a fuel lever gauge 15, performing the control of every kind. In addition, an optimum fuel quantity is detected, outputting an injection signal to a fuel injection nozzle 9, and the injection timing and injection quantity of fuel are controlled. In a comparing means, a fuel level variation calculated by a fuel level variation detecting means and an amount of fuel consumption integrated by a fuel consumption integrating means are compared with each other. A failure with the fuel level detecting means 15 is diagnosed on the basis of the compared result by a trouble detecting means. Thus, at the trouble in the fuel lever detecting means, an erroneous diagnosis in another diagnosis being related by mistake is gone, so that drop of the accuracy of diagnosis is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure diagnostic device for a fuel level detecting means of an internal combustion engine, and more particularly, to preventing erroneous diagnosis based on a failure of a fuel level detecting means used in a misfire diagnostic device of an internal combustion engine. The present invention relates to a failure diagnosis device for a fuel level detecting means.

[0002]

2. Description of the Related Art Conventionally, a fuel level detecting means is disposed in a fuel tank of an internal combustion engine, and the amount of fuel in the fuel tank, that is, the fuel level is detected by the fuel level detecting means. The detection result is used as a detection element of the diagnosis when performing various diagnoses of the internal combustion engine.

On the other hand, in the North American regulations on self-diagnosis of internal combustion engines for automobiles, the fuel in the fuel tank runs out,
In a so-called diagnostic system affected by a shortage of gas, it is recognized that the diagnosis is stopped when the remaining amount of fuel in the fuel tank becomes 15% or less of the fuel tank capacity. Specific examples of the diagnosis include a misfire diagnosis for an internal combustion engine and a leak diagnosis for evaporative gas.

[0004] The misfire diagnosis of the internal combustion engine is generally performed by
Focusing on the fact that the rotational speed decreases due to misfire, it diagnoses whether or not a misfire has occurred by detecting fluctuations in the rotational speed of the internal combustion engine, and diagnoses the failure of the internal combustion engine based on the misfire diagnosis. However, even when the fuel in the fuel tank is low, misfire of the internal combustion engine may occur, and there is a problem that the misfire cannot be distinguished from other misfires due to the failure of the internal combustion engine. For this reason, it is common practice to stop the misfire diagnosis using the fuel level detecting means, and when the fuel level detecting means indicates a value of the fuel in the fuel tank lower than a predetermined fuel level. I have.

[0005] In addition, the above-mentioned evaporative gas leak diagnosis is generally performed to detect whether or not evaporative gas is leaking from the fuel tank by detecting the pressure in the fuel tank. Is affected by the remaining amount of fuel in the tank, and when the remaining amount is small, leak diagnosis may not be performed. Therefore, similarly to the misfire diagnosis, the fuel level detection means is used, and when the fuel level detection means indicates a value of the fuel in the fuel tank lower than a predetermined fuel level, the leak diagnosis is stopped. That is being done.

[0006]

When the fuel level detecting means is used for the misfire diagnosis or the evaporative gas leak diagnosis of the internal combustion engine, if the fuel level detecting means fails for any reason, Despite the fuel remaining in the fuel tank being less than the prescribed amount,
In some cases, such detection is not performed, and the misfire diagnosis or the evaporative gas leak diagnosis may not be interrupted by detecting and determining that the remaining amount of fuel is greater than a predetermined amount, causing a misdiagnosis.

The present invention has been made in view of such a problem, and an object of the present invention is to diagnose whether or not a fuel level detecting means has failed, and to determine whether the fuel level detecting means has failed, It is an object of the present invention to provide a failure detection device of a fuel level detection means capable of prohibiting or stopping the diagnosis of the fuel.

[0008]

In order to achieve the above object,
A failure diagnosis device for a fuel level detection unit according to the present invention includes a fuel injection unit, a fuel tank that stores fuel for the fuel injection unit, a fuel level detection unit that detects a remaining amount of fuel in the fuel tank, And a control device, wherein the control device comprises:
A fuel consumption integrating means for integrating an amount of fuel injected from the fuel injection means, a fuel level change detecting means receiving an output signal of the fuel level detecting means, and comparing the integrated fuel consumption with the fuel level change And a failure detecting device for detecting a failure of the fuel level detecting means based on a comparison signal of the comparing means.

Further, a more specific embodiment of the failure detecting device of the fuel level detecting means according to the present invention is characterized in that the fuel level change amount detecting means detects when the integrated value by the fuel consumption integrating means is not less than a predetermined value. Calculating the difference between the fuel level and the fuel level immediately after the start of the internal combustion engine, and the failure detection device determines whether the comparison result between the fuel consumption integrating means and the fuel level change calculating means is outside a predetermined range. It is characterized in that it is determined that the fuel level detecting means has failed, and the fuel level change amount calculating means calculates the fuel level change amount only when the vehicle equipped with the internal combustion engine is stopped.

Further, when the failure detecting means detects a failure in the fuel level detecting means, the control device controls to prohibit another diagnosis of the internal combustion engine using the fuel level detecting means, and The control device includes a fuel level change speed judging means, and the fuel level change speed judging means, when the increasing speed of the fuel level change based on the fuel level change amount detecting means becomes equal to or more than a predetermined value, the fuel level change speed judgment means Determining that the fueling operation is being performed, wherein the fuel consumption integrating means resets the fuel consumption integrating result when the fueling operation to the fuel tank is detected, and further includes the fuel level change. The amount detecting means calculates a difference between the fuel level at the time when the product value obtained by the fuel consumption integrating means becomes a predetermined value or more and the fuel level immediately after the reset. It is set to.

[0011] In the fault diagnosis device of the fuel level detecting means of the present invention configured as described above, in the fault diagnosis control, the level detection signal of the fuel level detecting means disposed in the fuel tank of the internal combustion engine is used as the fuel level of the control device. The level change amount is input to the level change amount detecting means to calculate the level change amount of the fuel in the fuel tank. The fuel change speed determining means calculates a change speed of the change amount of the fuel level by the fuel level change amount detecting means, and when a rising speed of the fuel level change becomes a predetermined value or more, during a refueling operation to the fuel tank or the like. Is determined.

On the other hand, the detection signals of the respective operating state detecting means of the internal combustion engine are also input to the control device, the fuel supply amount calculating means calculates the amount of fuel supplied to the internal combustion engine, and the fuel consumption integrating means calculates the fuel consumption. The calculated fuel amount, that is, the consumed fuel amount is integrated. The comparing means compares the fuel level change calculated by the fuel level change detecting means with the fuel consumption integrated by the fuel consumption integrating means, and the failure detecting means compares the fuel level based on the comparison result. When the difference between the change amount and the integrated fuel consumption is equal to or larger than a predetermined range, it is diagnosed that the fuel level detecting means has failed. If a failure is diagnosed,
Diagnosis is prohibited by another diagnosis device such as a misfire diagnosis device by the diagnosis prohibiting device.

Since the failure diagnosis apparatus for the fuel level detection means of the present invention is controlled as described above, when the fuel level detection means fails, there is no erroneous diagnosis in other diagnosis related to the failure. A decrease in accuracy can be prevented.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the overall configuration of an electronically controlled fuel injection device for an automotive internal combustion engine according to the present embodiment. The internal combustion engine 1 has an intake manifold (intake pipe) 8 and an exhaust pipe 17 above each cylinder 1a.
The intake air enters through the air inlet 2 of the air cleaner 3, is guided through the throttle valve 4 and the surge tank 7, is distributed to each cylinder 1 a by the intake manifold 8, and is supplied to each of the engines 1. Cylinder chamber 1 of cylinder 1a
b. The combustion exhaust gas from the cylinder chamber 1a is guided to an exhaust pipe 17, and is discharged outside through a catalytic converter 10 connected to the exhaust pipe 17.

On the other hand, the fuel is sucked and pressurized from a fuel tank 14 by a fuel bomb (not shown), supplied to a fuel injection valve 9 provided in an intake manifold 8, and injected. At this time, the fuel pressure acting on the fuel injection valve 9 is regulated by a fuel pressure regulating valve (not shown) .The fuel pressure regulating valve introduces a negative pressure of the intake manifold 8, and the fuel pressure and the pressure inside the intake manifold 8 are increased. It functions to keep the pressure difference constant at all times.

An air flow meter (AFM) 5 for measuring intake air flow and a throttle sensor 6 are arranged in the intake pipe to detect the amount of intake air and to detect the opening of the throttle valve 4. An oxygen sensor 11 is arranged in the exhaust pipe 17 to detect the oxygen concentration in the combustion exhaust gas. The fuel tank 1
4 is provided with a fuel level gauge 15 for detecting the amount of fuel.

A control unit 12 is arranged in the internal combustion engine 1. The control unit 12 includes the air flow meter 5, the throttle sensor 6, and the oxygen sensor 1.
1 and inputting the output signal of the fuel level gauge 15 to perform various controls, detect the optimum fuel amount, output an injection signal to the fuel injection nozzle 9,
Control the injection volume.

Further, the temperature of the cylinder 1a of the internal combustion engine 1 is detected by a water temperature sensor (not shown) and inputted to the control unit 12, and a reference signal for detecting the engine speed, controlling the fuel injection timing and the ignition timing, Detected by a cam angle sensor (not shown), the control unit 12
Is input to Further, the ignition timing of the ignition plug 16 is also ignited through an ignition coil by energizing an igniter (not shown).

FIG. 2 is a block diagram showing the internal configuration of the control unit 12 of the present embodiment. The control unit 12 includes an MPU 100, a read / write RAM 101, a read-only ROM, and an I / OLSI 103 for controlling input / output.
The connections are made at 4, 105 and 106 to exchange data. The PMU 100 receives the signal indicating the engine state from the I / OLSI 103 via the bus 106, sequentially calls the processing contents stored in the ROM 102, performs a predetermined calculation, and then performs each of the actuators (the injector 9, the igniter, the auxiliary A drive signal to the air valve or the like is supplied through an I / OLSI.

FIG. 3 is a control block diagram of the failure diagnostic device for the fuel level detecting means of the present embodiment. The control device (control unit) 12 of the internal combustion engine 1 includes a fuel supply amount calculating unit 22, a fuel consumption integrating unit 23, a fuel level change detecting unit 24, a comparing unit 25,
The apparatus includes a failure detection unit 26, a diagnosis prohibition unit 27, and a fuel level change speed determination unit 28, and performs failure diagnosis control of the fuel level detection unit.

In the failure diagnosis control, the fuel level detecting means 15 provided in the fuel tank 14 of the internal combustion engine 1 is used.
Control signal (control unit)
The fuel level change amount of the fuel in the fuel tank is calculated by inputting it to the fuel level change amount detecting means 24 of FIG. In the fuel change speed determining means 28, the fuel level change amount detecting means 24
The change speed of the change amount of the fuel level is calculated, and when the increase speed of the fuel level change becomes equal to or more than a predetermined value, it is determined that the fuel tank is being refueled.

On the other hand, each operating state detecting means 2 of the internal combustion engine 1
1 is input to the control unit (control unit) 12, and the fuel supply amount calculating means 22 calculates the amount of fuel supplied to the internal combustion engine 1, that is, the injection amount injected from the fuel injection valve 9. Then, the fuel amount injected by the fuel consumption integrating means 23, that is, the consumed fuel amount is integrated.
In the comparing means 25, the fuel level change detecting means 24
Is compared with the fuel consumption integrated by the fuel consumption integration means 23, and the failure detection means 26 compares the fuel level change and the integrated fuel consumption based on the comparison result. If the difference is equal to or larger than the predetermined range, it is diagnosed that the fuel level detecting means 15 has failed. If the fuel level detection means 15 is diagnosed as having failed, the diagnosis prohibition means 2
At 7, control is performed to prohibit diagnosis by other diagnostic devices such as a misfire diagnostic device.

FIG. 4 is a control flowchart of the failure detection device for detecting a fuel level according to the present embodiment. Step 10
In step 01, it is determined whether or not a predetermined time has elapsed after the start. If not, the determination is repeated. If the predetermined time has elapsed, the process waits until stepping.
Proceed to 002. At step 1002, the initial fuel level of the fuel tank 14 is measured by the fuel level gauge 15, and the process proceeds to step 1003. In step 1003, a fuel consumption integrated value SUMFC, which will be described later, is calculated. In step 1004, it is determined whether the vehicle is stopped. If the vehicle is not stopped, the process returns to step 1003 and the fuel consumption integrated value SU
Continue to accumulate MFC.

If it is determined that the vehicle is stopped, the process proceeds to step 1005, where it is determined whether or not the fuel is being refueled. If the vehicle is being refueled, the fuel consumption integrated value SUMFC and the refueling flag are set at step 1006. Clear and step 1
Return to 002. If it is determined in step 1005 that refueling is not being performed, the process proceeds to step 1007. Step 10
In 07, it is determined whether the fuel consumption integrated value SUMFC is equal to or greater than a predetermined value. If the fuel consumption integrated value SUMFC is equal to or greater than the predetermined value, the process proceeds to step 1008; Return to

In step 1008, the current fuel level FLVL in the fuel tank 14 is measured by the fuel level gauge 15, and the flow advances to step 1009. In step 1009, the fuel level change DLTFG is reduced by the fuel level FLIN.
It is calculated as the difference between T and the fuel level FLVL, and the process proceeds to step 1010. In step 1010, it is determined whether or not the difference between the fuel level change DLTFG and the fuel consumption integrated value SUMFC is within a predetermined range.

If it is determined in step 1010 that the current value is within the predetermined range, the flow ends with no abnormality. If it is determined in step 1010 that the value is equal to or larger than the predetermined range,
Proceeding to step 1011, the fuel level detecting means detects the abnormal N
The flow ends as G is determined. In FIG. 4, the step 1007 may be configured to compare whether or not the running distance after starting is equal to or more than a predetermined value.

FIG. 5 is a control flow for calculating the drive pulse width Ti of the injector 9 when fuel is injected from the injector 9. In step 1101, the basic pulse width Tp is calculated, and the flow advances to step 1102. The basic pulse width Tp is calculated by the following equation (1).

[0028]

Tp = Ki × XQa / Ne (1) where Tp: basic pulse width, K: injector injection amount correction coefficient, Qa: intake air amount, Ne: engine speed. Next, in step 1102, various correction coefficients COE
Calculate F. The various correction coefficients COEF include a water temperature correction coefficient calculated according to the engine water temperature, an air-fuel ratio correction coefficient calculated according to the engine speed and the load, and a post-start correction coefficient calculated according to the time after the start. . In addition,
These correction coefficients COEF are calculated by searching values stored in the ROM in advance for values corresponding to the respective parameters.

In step 1103, α calculated by the air-fuel ratio feedback control is read, and in step 1104, Lα, which is a learning correction coefficient of α, is read. Step 11
At 05, the invalid pulse width Ts of the injector 9 is read,
In step 1106, the injector 9
Is calculated, the calculated value is set in an injection register (not shown), and the flow ends. Also, at a predetermined injection timing, an injector injection pulse corresponding to the data set in the injection register is output.

FIG. 6 shows a flowchart for integrating the fuel consumption. In step 1201, the invalid pulse width Ts of the injector 9 is subtracted from the driving pulse width Ti of the injector 9 to calculate the actual injection amount Tir, and the process proceeds to step 1202. In step 1202, the actual injection amount T
ir integration processing, that is, the fuel consumption integrated value SUMFC is calculated, and the flow ends.

FIG. 7 shows the characteristics of the fuel level detecting means, in which the output voltage decreases as the fuel level increases. FIG. 8 shows a flowchart of the fueling operation detection. In step 1301, the fuel level change speed is measured, and the process proceeds to step 1302, where it is determined whether the fuel level change distance is large. If the speed of change is high, step 13
Proceeding to 03, the refueling flag is set to 1, and the flow ends. If the change speed is low, the flow ends.

As described above, one embodiment of the present invention has been described in detail. However, the present invention is not limited to the above-described embodiment, and a design may be made without departing from the spirit of the invention described in the appended claims. Various changes can be made.

[0033]

As can be understood from the above description, the failure diagnosis device for the fuel level detecting means of the present invention eliminates erroneous diagnosis in other related diagnosis when the fuel level detecting means fails. In addition, it is possible to prevent a decrease in diagnosis accuracy.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an engine system showing one embodiment of a failure diagnosis device for a fuel level detection means of the present invention.

FIG. 2 is an internal configuration diagram of a control unit of the failure diagnosis device for the fuel level detection means in FIG. 1;

FIG. 3 is a control block diagram of the failure diagnosis device of FIG. 1;

FIG. 4 is a flowchart of failure detection of the failure diagnostic device of FIG. 1;

FIG. 5 is a flowchart for calculating the injector drive pulse width of the failure diagnostic device of FIG. 1;

FIG. 6 is a flowchart of fuel consumption integration of the failure diagnostic device of FIG. 1;

FIG. 7 is a characteristic diagram of a fuel level detecting means of the failure diagnostic device of FIG. 1;

FIG. 8 is a flowchart of detecting a refueling operation of the failure diagnostic device of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 12 Control device (control unit) 15 Fuel level detecting means 22 Fuel supply amount calculating means 23 Fuel consumption calculating means 24 Fuel level change amount detecting means 25 Comparison means 26 Failure detecting means 27 Diagnosis inhibiting means 28 Fuel level changing speed Judgment means

Claims (6)

[Claims] 1. An internal combustion engine comprising: a fuel injection means; a fuel tank for storing fuel in the fuel injection means; a fuel level detection means for detecting a remaining fuel amount in the fuel tank; In the failure diagnosis device for a fuel detection unit, the control unit includes a fuel consumption integration unit that integrates an amount of fuel injected from the fuel injection unit, a fuel level change amount detection unit that receives an output signal of the fuel level detection unit, A comparison unit for comparing the integrated fuel consumption with the fuel level change amount, and a failure detection device for detecting a failure of the fuel level detection unit based on a comparison signal of the comparison unit. A failure diagnosis device for a fuel level detection means of an internal combustion engine. 2. The fuel level change detecting means calculates a difference between a fuel level at that time and a fuel level immediately after the start of the internal combustion engine when an integrated value obtained by the fuel consumption integrating means is equal to or more than a predetermined value. 2. The detection device according to claim 1, wherein the detection device determines that the fuel level detection unit has failed if the comparison result between the fuel consumption integration unit and the fuel level change amount calculation unit is out of a predetermined range. 3. Diagnostic device for a fuel level detecting means of an internal combustion engine. 3. The internal combustion engine according to claim 1, wherein the fuel level change amount calculating means calculates the fuel level change amount only when the vehicle equipped with the internal combustion engine is in a stopped state. Failure diagnosis device for fuel level detection means. 4. The control device according to claim 1, wherein when the failure detection means detects a failure in the fuel level detection means, the control device controls to prevent another diagnosis of the internal combustion engine using the fuel level detection means. Item 4. A failure diagnostic device for a fuel level detecting means of an internal combustion engine according to any one of Items 1 to 3. 5. The fuel consumption integration means resets the fuel consumption integration result when a fueling operation to the fuel tank is detected, and the fuel level change detection means includes a fuel consumption change detection means. 5. The fuel level detecting means for an internal combustion engine according to claim 1, wherein a difference between the fuel level at the time when the product value obtained by the quantity integrating means becomes equal to or more than a predetermined value and the fuel level immediately after the reset is calculated. Fault diagnosis device. 6. The control device according to claim 1, further comprising a fuel level change speed determining unit, wherein the fuel level change speed determining unit determines that a rising speed of the fuel level change based on the fuel level change amount detecting unit becomes a predetermined value or more. 6. The failure diagnosis device for a fuel level detection means of an internal combustion engine according to claim 1, wherein it is determined that a fuel supply operation to the fuel tank is being performed.