JP2000080964A - Failure diagnosing device for fuel reserving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To diagnose the existence of failure of a separating wall for dividing the inside of a fuel reserving device into a fuel chamber and an air chamber by detecting a rate of fuel component in an internal combustion engine after a cutout valve of a gas introducing passage connected to an intake passage in an internal combustion engine is opened or closed. SOLUTION: In a fuel reserving device 1 provided with a fuel tank 6 which is capable of deforming according to a fuel rate and for separating an inner space of a housing 4 into a fuel chamber 5 and an air chamber 10, an inside canister evaporation fuel discharging pipe 28 provided with a purge control valve 29 and an oiling pipe inside evaporation fuel discharging pipe 31 provided with a diagnosing valve 32 are provided, the discharging pipe 28 is arranged for introducing gas in the air chamber 10 into an intake passage 30 of an internal combustion engine main body 16, and the discharging pipe 31 is arranged for discharging evaporation fuel in an oiling pipe 11. The diagnosing valve 32 is closed, purge is carried out in a condition in which it is closed that evaporation fuel is introduced from an inside of the oiling pipe 11, and evaporation fuel concentration is detected by an air-fuel ratio sensor 36. When the concentration is not less than concentration to be beforehand set in a predetermined time, it is diagnosed that a hole is opened to the fuel tank 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel tank failure diagnosis apparatus.

[0002]

2. Description of the Related Art When there is a space above a fuel level in a fuel tank, fuel vapor is generated, and the fuel vapor may be discharged from the fuel tank to the atmosphere. Therefore, JP-A-7-
In 132327, an inflatable and deflated airbag is arranged in the fuel tank, and the airbag is moved in accordance with the displacement of the fuel level in the fuel tank so that the airbag is always in close contact with the fuel level in the fuel tank. Expands and contracts.

Further, in the fuel tank disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-132737, the internal space of the airbag is provided to a canister for adsorbing the evaporated fuel so that the evaporated fuel permeated through the airbag is not released to the outside of the airbag. Connected.

[0004]

SUMMARY OF THE INVENTION The above-mentioned JP-A-7-132
When the airbag repeatedly inflated and deflated in the 738 fuel tank, holes were opened due to aging or collision of the airbag with surrounding members, and the material of the airbag swelled or permeated the fuel. Sometimes it is necessary to detect that a fuel tank has failed. However, the fuel tank does not have a function of detecting a failure of the fuel tank. Accordingly, an object of the present invention is to diagnose whether or not a failure has occurred in a separation wall that separates the inside of a fuel storage device into a fuel chamber and an air chamber.

[0005]

According to a first aspect of the present invention, there is provided a fuel storage device for storing fuel, wherein an internal space of the fuel storage device includes a fuel chamber and an air chamber. A failure diagnosing device for the fuel storage device, wherein the separation wall is deformable in the fuel storage device according to the amount of fuel in the fuel chamber. A gas introduction passage for introducing the gas into the intake passage, a shutoff valve for shutting off the gas introduction passage, and an amount of a fuel component in the internal combustion engine after opening or closing the shutoff valve. Detecting the fuel component in the gas introduced into the intake passage based on the fuel component amount detected by the fuel component amount detecting means, and detecting that the fuel component exists in the gas. When the separation wall is detected, ; And a fault diagnosis means for diagnosing to be disabled. That is, the failure of the separation wall is diagnosed based on the amount of the fuel component in the internal combustion engine after the opening or closing of the shutoff valve.

According to a second aspect of the present invention, in the first aspect, the failure diagnosing means determines the amount of the fuel component detected by the fuel component detecting means as a predetermined fuel component amount. The fuel component in the gas introduced into the intake passage is detected by comparison. That is, the failure of the separation wall is diagnosed by comparing the amount of the fuel component in the internal combustion engine after opening or closing the shutoff valve with a predetermined amount of the fuel component.

According to a third aspect of the present invention, in the first aspect, the fuel component amount detecting means includes an amount of a fuel component in the internal combustion engine before opening or closing the shutoff valve. The failure diagnosis means is introduced into the intake passage based on a change in the fuel component amount in the internal combustion engine before and after opening or closing the shutoff valve detected by the fuel component amount detection means. Detects fuel components in gas. That is, the failure of the separation wall is diagnosed based on the change in the fuel component amount in the internal combustion engine before and after the opening and closing of the shutoff valve.

According to a fourth aspect of the present invention, in the first aspect, the fuel component amount detecting means is disposed in the intake passage and detects the amount of the fuel component in the intake air. That is, the failure of the separation wall is diagnosed based on the amount of the fuel component in the intake air. According to a fifth aspect of the present invention to solve the above problems, in the first aspect,
The fuel component amount detecting means includes an air-fuel ratio sensor disposed in an exhaust passage of the internal combustion engine, and detects an amount of a fuel component in the internal combustion engine based on an air-fuel ratio in exhaust gas detected by the air-fuel ratio sensor. To detect. That is, the failure of the separation wall is diagnosed based on the air-fuel ratio in the exhaust gas.

According to a sixth aspect of the present invention, in the first aspect, the gas introduction passage further introduces gas in the fuel chamber into an intake passage of an internal combustion engine, and the shut-off valve is The introduction of gas from one of the fuel chamber and the air chamber into the intake passage is stopped. According to a seventh aspect of the present invention, in order to solve the above problem, in the first aspect, the failure diagnosing means includes a fuel whose fuel component amount is predetermined in the internal combustion engine after opening or closing the shutoff valve. When the amount is larger than the component amount, it is diagnosed that a hole is formed in the separation membrane, and when the fuel component amount in the internal combustion engine after opening or closing the shutoff valve is smaller than the predetermined fuel component amount, the fuel It is diagnosed that the fuel in the room has permeated the separation membrane. That is, the perforation of the separation membrane and the permeation of the fuel component through the separation membrane are diagnosed based on the fuel component. The perforation of the separation membrane and the permeation of the fuel component through the separation membrane correspond to the failure of the separation membrane.

According to an eighth aspect, in the first aspect, the introduction of air into the air chamber is interrupted while the failure diagnosis means diagnoses a failure in the separation wall. According to a ninth aspect, in the first aspect, the failure diagnosis means shuts off the gas introduction passage by the shutoff valve after the gas in the air chamber is introduced into the intake passage through the gas introduction passage. Then, a failure of the fuel storage device is diagnosed based on the pressure in the air chamber after the gas introduction passage is shut off by the shut-off valve.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel storage device according to a first embodiment of the present invention will be described with reference to the drawings. The fuel storage device 1 is used, for example, as a tank for storing fuel to be supplied to an internal combustion engine. Of course, it can also be used simply as a tank for storing fuel. Referring to FIG. 1, the fuel storage device 1 includes a housing 4 having an upper portion 2 and a lower portion 3 having a substantially bowl shape. The upper part 2 and the lower part 3 are connected to each other at flanges 2a, 3a formed on their periphery. A fuel container or fuel tank 6 that defines a fuel chamber 5 for storing fuel is disposed in the housing 4.

Referring to FIG. 2 and FIG. 3, a fuel tank 6 of the first embodiment has a pair of substantially rectangular upper and lower walls 7 and 8 which are vertically arranged with respect to each other. , Four substantially rectangular side walls 9a connecting corresponding sides of each other
To 9d. These side walls 9a to 9d are connected at both ends to the edges of the adjacent side walls. The fuel tank 6 has a substantially rectangular parallelepiped shape, and the fuel chamber 5 is formed therein. Therefore, each wall of the fuel tank 6 corresponds to a separation wall that separates the inside of the fuel storage device 1 into the fuel chamber 5 and the air chamber 10. The upper wall 7, the lower wall 8, and the side walls 9a to
9d is formed in a multilayer structure in which both surfaces of a flat core portion made of a copolymer resin of ethylene and vinyl or nylon are covered with a skin portion made of high-density polyethylene,
It is substantially rigid.

The area of the upper wall 7 or the lower wall 8 of the fuel tank 6 is larger than the area of one of the side walls 9a to 9d.
The rigidity of the upper wall 7 and the lower wall 8 is smaller than the rigidity of the side walls 9a to 9d. The shape of the upper wall 7 and the lower wall 8 is not limited to a rectangle, but may be any paired polygon. Therefore, the upper wall 7,
The shapes of the lower wall 8 and the side walls 9a to 9d may be appropriately selected according to the shape of the space in which the fuel tank 6 is to be arranged.

As shown in FIG. 4, when fuel is supplied into the fuel tank 6 and the fuel tank 6 has a rectangular parallelepiped shape, the amount of fuel that can be stored (hereinafter referred to as a predetermined amount) is determined by the amount of fuel in the fuel tank 6. Is exceeded, the upper wall 7 and the lower wall 8 are curved and deformed so as to be separated from each other and swell outward, and the side walls 9a to 9d are curved and deformed so as to approach each other and be depressed inward. That is, in the first embodiment, when the amount of fuel in the fuel tank 6 exceeds a predetermined amount, the upper wall 7 is displaced upward, the lower wall 8 is displaced downward, and the side walls 9a to 9d are displaced laterally and inward. . Thus, the amount of fuel that can be stored in the fuel tank 6 gradually increases. The amount of deformation of the upper wall 7 and the lower wall 8 is determined by the side walls 9a to 9d.
Greater than the amount of deformation.

On the other hand, as shown in FIG. 5, when the fuel is discharged from the fuel tank 6 and the fuel amount in the fuel tank 6 becomes smaller than a predetermined amount, the upper wall 7 and the lower wall 8 approach each other and move inward. The side walls 9a to 9d are curved and deformed so as to be depressed inward as they approach each other. That is, in the first embodiment, when the amount of fuel in the fuel tank 6 becomes smaller than a predetermined amount, the upper wall 7 is displaced downward, the lower wall 8 is displaced upward, and the side walls 9a to 9d are displaced laterally and inward. . Thus, the amount of fuel that can be stored in the fuel tank 6 gradually decreases.

Referring again to FIG. 1, fuel is supplied to the fuel tank 6.
The lower end of the oil supply pipe 11 for supplying the fuel into the fuel tank 6
To a substantially central portion of the lower wall 8. On the other hand, a lid 12 for closing the oil supply pipe 11 is detachably attached to an upper end of the oil supply pipe 11. When supplying fuel into the fuel tank 6, the lid 12 is removed, and fuel is supplied from the upstream end of the fuel supply pipe 11.

One end of a fuel introduction pipe 14 for introducing the fuel in the fuel tank 6 to the fuel pump device 13 is connected to an intermediate position of the fuel supply pipe 11. The other end of the fuel introduction pipe 14 is connected to the fuel pump device 13. A fuel pump (not shown) is arranged in the fuel pump device 13. The fuel in the fuel pump device 13 is supplied to the engine body 16 via the fuel supply pipe 15 by the fuel pump.

The fuel pump device 13 is connected to one end of a pump fuel vapor discharge pipe 17 for discharging the fuel vapor in the fuel pump device 13 into the upper portion of the fuel supply pipe 11. The other end of the fuel vapor discharge pipe 17 in the pump is connected to the fuel supply pipe 11.
Is connected to the upper part.

At a substantially central portion of the upper wall 7 of the fuel tank 6, one end of an in-tank evaporative fuel discharge pipe 18 for discharging gas in the fuel tank 6, particularly, evaporative fuel, to the outside of the fuel tank 6 is provided with a shutoff valve 19. Connected via. On the other hand, the other end of the in-tank evaporated fuel discharge pipe 18 is connected to the fuel pump device 13 and opens to a space (not shown) in the fuel pump device 13. In addition, the fuel vapor discharge pipe 18 in the tank has flexibility so as to follow the displacement of the upper wall 7 of the fuel tank 6.

The shut-off valve 19 has a float 20 that can float on the fuel level. Therefore, when the fuel level in the fuel tank 6 reaches the shut-off valve 19, the float 20 rises to close the opening of the tank-evaporated fuel discharge pipe 18 and shut off the tank-evaporated fuel discharge pipe 18. Therefore, the fuel does not leak out of the fuel tank 6.

A check valve 2 is connected to the fuel vapor discharge pipe 18 in the tank.
1 is attached. The check valve 21 is opened when the pressure in the fuel vapor discharge pipe 18 in the tank between the check valve 21 and the shut-off valve 19 exceeds a predetermined positive pressure. Close when low. Therefore, gas such as air and evaporated fuel does not enter the fuel tank 6 after the shut-off valve 19 is once shut off.

When the upper wall 7 of the fuel tank 6 expands upward, the fuel tank 6
A contact plate 22 that contacts the upper wall 7 is attached. A fuel detecting device 23 for detecting the amount of fuel in the fuel tank 6 is attached to the lower surface of the upper portion 2 of the housing 4. The fuel detector 23 detects the displacement of the upper wall 7 of the fuel tank 6 and detects the amount of fuel in the fuel tank 6.

The air chamber 10 of the fuel tank 6 communicates with the atmosphere via a charcoal canister 24. The charcoal canister 24 has activated carbon 25 therein. The activated carbon 25 divides the space inside the charcoal canister 24 into an air chamber side space 26 and an atmosphere side space 27. Air chamber side space 2
6 communicates directly with the air chamber 10. On the other hand, the atmosphere side space 27
Is in direct communication with the atmosphere. Charcoal canister 24
Is connected to one end of an in-canister fuel vapor discharge pipe 28, which opens into the air chamber side space 26. On the other hand, the other end of the fuel vapor discharge pipe 28 in the canister is connected to the surge tank 3 in the intake passage.
3 is connected. Also, the fuel vapor discharge pipe 28 in the canister
Is provided with a purge control valve 29. Here, purging refers to introducing vaporized fuel into the intake passage 30 by negative pressure in the intake passage. When the purge control valve 29 introduces the evaporated fuel into the intake passage 30, the engine operation state (for example,
Opening / closing control is performed according to the intake air amount, the rotation speed, and the engine load. The purge control valve 29 is controlled to open and close as described later when performing a failure diagnosis of the fuel storage device 1. When the purge control valve 29 is closed, the communication between the fuel vapor discharge pipe 28 in the canister and the intake passage 30 is cut off.

An evaporative fuel discharge pipe 31 for discharging the fuel vapor in the fuel pipe 11 is provided above the fuel pipe 11.
Are connected at one end. On the other hand, the fuel vapor discharge pipe 3
The other end of 1 is a purge control valve 29 and a charcoal canister 2
4 and is connected to the fuel vapor discharge pipe 28 in the canister between the pipes 4 and 4. A diagnosis valve 32 is attached to the fuel vapor evacuation pipe 31 in the fuel supply pipe. The diagnosis valve 32 is opened and closed as described later when performing a failure diagnosis of the fuel storage device 1. When the diagnostic valve 32 is closed, communication between the fuel supply pipe inside the fuel supply pipe 31 and the fuel supply pipe 28 in the canister is cut off.
Therefore, the diagnostic valve of the first embodiment corresponds to a shut-off valve for stopping the introduction of fuel vapor from the fuel chamber into the suction passage.

The intake passage 30 on the upstream side of the surge tank 33
Inside, a throttle valve 34 is arranged. Throttle valve 3
4 is controlled to open and close according to the amount of air to be supplied to the engine body 16. If the throttle valve 34 is not completely opened, a negative pressure is generated in the surge tank 33. Therefore, when the purge control valve 29 is open, a negative pressure is introduced into the charcoal canister 24. Therefore, the fuel vapor in the charcoal canister 24 is introduced into the intake passage 30.

The exhaust passage 3 connected to the engine body 16
5 is provided with an air-fuel ratio sensor 36 for detecting the air-fuel ratio in the exhaust gas. In this specification, “upstream” and “downstream” are used in accordance with the flow of air in the intake passage 30.

The air-fuel ratio sensor 36 is an electronic control unit (EC
U) 37. Therefore, the signal of the air-fuel ratio sensor 36 is input to the electronic control unit 37. Further, the purge control valve 29 and the diagnostic valve 32 are also connected to the electronic control device 37, and are controlled to be opened and closed by the electronic control device 37. Further, the fuel storage device of the first embodiment includes a first alarm device 38a and a second alarm device 38b that are operated as described later. The first alarm device 38a and the second alarm device 38b are connected to the electronic control device 37, respectively.
The operation is controlled by.

Next, an outline of failure diagnosis of the fuel storage device of the first embodiment will be described. When the fuel storage device 1 is normal, no evaporated fuel is generated in the air chamber 10. Therefore, during execution of the purge, the evaporated fuel generated in the fuel supply pipe 11 and the evaporated fuel adsorbed in the charcoal canister 24 are introduced into the intake passage 30. After all the evaporated fuel adsorbed in the charcoal canister 24 is introduced into the intake passage 30, only the evaporated fuel generated in the fuel supply pipe 11 is introduced into the intake passage 30.

Further, the purge control valve 2 during the execution of the purge
The valve opening amount of No. 9 is increased as the intake air amount increases. Therefore, after all of the evaporated fuel adsorbed in the charcoal canister 24 is introduced into the intake passage 30, the evaporated fuel concentration (hereinafter, purge concentration) in the intake air is generated in the fuel supply pipe 11 per unit time. It is proportional to the amount of fuel vapor.
Therefore, the purge concentration is always maintained at a predetermined concentration or less, except when an unexpectedly large amount of fuel vapor is generated in the fuel supply pipe 11. The method of calculating the purge concentration will be described later.

However, when a failure such as perforation or permeation of the fuel tank walls 7, 8, 9a to 9d occurs in the fuel storage device 1, the fuel components (evaporated fuel and liquid fuel) are transferred from the fuel chamber 5 to the air chamber 10. The fuel component enters the air chamber 10 as a liquid or a gas. As a result, fuel vapor is generated in the air chamber 10. Therefore, the purge concentration becomes higher than the predetermined concentration.

Therefore, in the first embodiment, the diagnostic valve 32 is closed when the purge concentration is equal to or higher than a predetermined concentration. When the diagnostic valve 32 is closed, the fuel vapor in the fuel supply pipe 11 is not introduced into the intake passage 30. Therefore, if there is no hole in the wall of the fuel tank 6 and there is no evaporated fuel in the charcoal canister 24, the purge concentration will be equal to the diagnostic valve 32.
Should be lower than a predetermined concentration within a predetermined time after the valve is closed. That is, when the purge concentration falls below a predetermined concentration within a predetermined time after closing the diagnostic valve 32, no hole is formed in the wall of the fuel tank 6, and the fuel storage device 1 is operated normally. Diagnose that On the other hand, when the purge concentration does not become lower than the predetermined concentration within a predetermined time after closing the diagnostic valve 32, a hole is formed in the wall of the fuel tank 6, and a large amount of evaporation is caused through the hole. Since the fuel is flowing into the air chamber 10, it is diagnosed that the fuel storage device 1 is out of order. Of course, the amount of fuel vapor can be used instead of the purge concentration.

Thus, according to the first embodiment, it is possible to diagnose a failure of the fuel storage device, which is a perforation in the wall of the fuel tank. Further, according to the first embodiment, the fault diagnosis can be executed any number of times during the execution of the purge. In the first embodiment, when the time until the purge concentration exceeds the predetermined concentration when the diagnostic valve is closed during the execution of the purge is shorter than the predetermined time, it is determined that the fuel storage device has failed. Diagnosis may be made.

Next, a method for calculating the concentration of the evaporated fuel in the intake air, that is, the purge concentration will be briefly described. In the internal combustion engine of the first embodiment, the valve opening time of the fuel injection valve when injecting fuel into the cylinder of the engine body 16, that is, the fuel injection time TAU is calculated based on the following equation. TAU = TB ・ FW ・ (FAF + KG-FPG) Here, TB is a basic fuel injection time required to bring the air-fuel ratio to a target air-fuel ratio, for example, a stoichiometric air-fuel ratio, and is a function of the engine speed and the intake air amount. Is stored in the electronic control unit 37 in advance. KG is an air-fuel ratio learning correction coefficient (a coefficient obtained based on the air-fuel ratio during feedback control of the fuel injection time). FW collectively includes a warm-up increase correction coefficient (a coefficient for increasing the fuel injection amount when the internal combustion engine is to be warmed up) and an acceleration increase correction coefficient (a coefficient for increasing the fuel injection amount during acceleration). It is a correction coefficient expressed as
FAF is a feedback correction coefficient for converting the actual air-fuel ratio to the stoichiometric air-fuel ratio based on the output signal of the air-fuel ratio sensor 36. When the target air-fuel ratio is the stoichiometric air-fuel ratio, the air-fuel ratio sensor 36 generates an output voltage of approximately 0.9 volts when the air-fuel ratio is rich (the fuel concentration in the intake air is higher than that of the stoichiometric air-fuel ratio). An oxygen sensor that generates an output voltage of about 0.1 volt when lean (the fuel concentration in the intake air is lower than that of the stoichiometric air-fuel ratio) is used. When the air-fuel ratio detected by the air-fuel ratio sensor 36 is rich, the feedback correction coefficient FAF is decreased by a certain value, and when lean, the FAF is increased by a certain value. Thus, the actual air-fuel ratio is made to match the stoichiometric air-fuel ratio. Note that the feedback correction coefficient FAF is 1.
It fluctuates around 0.

FPG is a purge correction coefficient expressed as a product (PGR.FGPG) of a purge rate PGR and an evaporative fuel concentration coefficient FGPG indicating an evaporative fuel concentration in intake air per unit purge rate. The purge rate PGR is a ratio of the amount of evaporated fuel to the amount of intake air, and can be obtained from the operating state of the engine and the opening ratio of the purge control valve 29.

Next, the fuel vapor concentration coefficient FGPG representing the fuel vapor concentration in the intake air per unit purge rate will be described. When the actual air-fuel ratio becomes rich after the purging operation is started, the feedback correction coefficient FAF gradually decreases so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. At this time, the higher the concentration of evaporated fuel in the intake air, the smaller the feedback correction coefficient FAF. Therefore, the evaporated fuel concentration in the intake air can be determined from the decrease amount of the feedback correction coefficient FAF. On the other hand, it is not preferable that the feedback correction coefficient FAF greatly deviates from 1.0. Therefore, after the purge operation is started, when the feedback correction coefficient FAF falls below the threshold value, the evaporated fuel concentration coefficient FGPG is gradually increased from zero, and the evaporated fuel concentration coefficient FGP is increased.
The feedback correction coefficient FAF is increased by the amount of increase of G. Therefore, after the purge action is started,
When the feedback correction coefficient FAF becomes 1.0 again, the fuel vapor concentration coefficient FGPG accurately represents the fuel vapor concentration in the intake air per unit purge rate, and the purge correction coefficient FGR (= PRG.FGPG) It accurately represents the concentration of evaporated fuel in the intake air. For a detailed calculation method of the concentration of the evaporated fuel in the intake air, see, for example,
See -305662.

Next, the details of the failure diagnosis of the fuel storage device of the first embodiment will be described with reference to the flowcharts of FIGS. First, in step S100, it is determined whether the failure diagnosis execution flag F is set (F = “1”). The failure diagnosis execution flag is set when the failure diagnosis is performed once, and is reset, for example, every predetermined time. However, the failure diagnosis execution flag may be reset when the engine is started. Step S1
When F = "1" at 00, the fault diagnosis has been executed once, and thus the process is terminated. On the other hand, F =
When the value is “0”, the failure diagnosis has not been executed, and the process proceeds to step S102 to execute the failure diagnosis.

In step S102 of FIG. 6, it is determined whether or not the purge control valve 29 is open, that is, whether or not purging is being performed. When the purge control valve 29 is open, it is determined that the failure diagnosis can be performed because the purge is being performed, and the routine proceeds to step S104, where the purge concentration C is determined.
P is calculated, and the process proceeds to step S106. On the other hand, when the purge control valve 29 is closed, it is determined that the failure diagnosis cannot be performed because the purge has not been performed, and the process proceeds to step S152 in FIG. Is cleared (C1 ← “0”), the process proceeds to step S154, and the failure counter C2 is cleared (C2 ← “0”), and the process ends. The normal counter is counted up when the fuel storage device 1 is diagnosed to be normal in the failure diagnosis, and when the failure diagnosis cannot be executed as described above and when there is a possibility that the fuel storage device 1 has failed. Cleared when diagnosed. Further, the failure counter is counted up when it is diagnosed that the fuel storage device 1 has failed in the failure diagnosis, and when the failure diagnosis cannot be executed as described above and when there is a possibility that the fuel storage device 1 is normal. Cleared when diagnosed.

In step S106 of FIG. 6, the purge concentration C
P is larger than the maximum purge concentration CPmax (CP> CP
max). When CP> CPmax, it is determined that a hole is formed in the wall of the fuel tank 6 and there is a possibility that an abnormality has occurred in the fuel storage device 1, and the process proceeds to step S108 to clear the normal counter C1 (C1). ← “0”), and then proceeds to step S110 to count up the failure counter C2 (C2 ← C2 + 1),
Next, the process proceeds to step S112, closes the diagnostic valve 32, and proceeds to step S114. On the other hand, when CP ≦ CPmax, it is determined that no hole is formed in the wall of the fuel tank 6, and the process proceeds to step S122.

In step S114 in FIG. 6, the failure counter C2 is larger than a predetermined maximum value C2max (C
2> C2max) is determined. C2> C2ma
If x, the purge concentration does not become smaller than the maximum purge concentration even if the failure counter is counted by the predetermined maximum value after the purge concentration is determined to be larger than the maximum purge concentration in step S106. Is determined to have failed, the flow proceeds to step S116, and the number N of failure diagnoses is counted up (N ← N +
1) Then, the process proceeds to step S139 in FIG.
, And then proceeds to step S140 to clear the normal counter C1 (C1 ← “0”), and then to step S14
2 to clear the failure counter C2 (C2 ←
"0"), and then proceeds to step S144 to set a failure diagnosis execution flag F (F ← "1"), and proceeds to step S146.
Proceed to. Note that the failure diagnosis count N is cleared when it is notified that the fuel storage device 1 has failed. On the other hand, if C2 ≦ C2max in step S114 of FIG. 6, the process ends because it cannot be determined that the fuel storage device 1 has failed at the present time.

In step S146 of FIG. 8, it is determined whether or not the number N of failure diagnoses is greater than the maximum number Nmax (N> Nmax). When N> Nmax, it is diagnosed that the fuel storage device 1 has failed more times than the maximum number. Therefore, the process proceeds to step S148 and the first alarm device 38a
To notify that the fuel storage device 1 is out of order,
Next, the routine proceeds to step S150, where the number N of failure diagnoses is cleared (N ← “0”), and the process ends. On the other hand, step S
If N ≦ Nmax in 146, the process ends because it should not be determined that the fuel storage device 1 has failed at the present time.

In step S122 of FIG. 6, it is determined whether the diagnostic valve 32 is closed. When the diagnostic valve 32 is closed, it is determined that the failure diagnosis is being executed, and the process proceeds to step S124 for further diagnosis. On the other hand, when the diagnostic valve 32 is open, it is determined that the purge is being performed but the failure diagnosis is not being performed, and the process is terminated.

In step S124 of FIG. 6, the purge concentration C
P is larger than the intermediate purge concentration CPmid (CP> CP
mid). Note that the intermediate purge concentration is smaller than the maximum purge concentration. When CP> CPmid, the purge concentration became smaller than the maximum purge concentration before the failure counter reached the predetermined maximum value. However, since the purge concentration was higher than the intermediate purge concentration, no hole was formed in the wall of the fuel tank 6. However, it is determined that the evaporative fuel has permeated the wall of the fuel tank 6, and the process proceeds to step S126 to activate the second alarm device 38b, and the evaporative fuel permeates through the wall of the fuel tank 6 and is discharged from the fuel chamber 5. The process proceeds to step S139 in FIG. The following steps have been described above and will not be described. When the process proceeds to step S146 after the operation of the second alarm device 38b, the number of failure diagnoses N is not counted up, so that in step S146 it is always determined that N ≦ Nmax, and the process ends. On the other hand, when CP ≦ CPmid in step S124, the purge concentration has become equal to or lower than the intermediate purge concentration before the failure counter reaches the predetermined maximum value.
It is determined that the fuel storage device 1 may be normal, and the process proceeds to step S128 in FIG. 7 to clear the failure counter C2 (C2 ← “0”), and then proceeds to step S130 to count the normal counter C1. Up (C1 ← C1 +
1), and proceed to step S132.

In step S132 of FIG. 7, the normal counter C1 is larger than a predetermined maximum value C1max (C
1> C1max) is determined. C1> C1ma
If x, the normal counter is counted by the predetermined maximum value after the purge concentration is determined to be equal to or less than the maximum purge concentration after it is determined in step S106 that the purge concentration is higher than the maximum purge concentration. It is determined that the storage device 1 is normal, and step S134
To count down the failure diagnosis frequency N (N ← N−
1) Then, the process proceeds to step S136, where it is determined whether or not the failure diagnosis frequency N is smaller than zero (N <0). When N <0, the number of failure diagnosis N is set to zero (N ← “0”),
The process proceeds to step S140 in FIG. The following steps have been described above and will not be described. On the other hand, when C1 ≦ C1max is satisfied in step S132, the process ends because the fuel storage device 1 cannot be determined to be normal at the present time.

According to the first embodiment, when the number of times that the fuel storage device is diagnosed as being faulty is larger than the number of times that the fuel storage device is diagnosed as normal by a predetermined value, the fuel storage device is activated. Warns that it is out of order. Therefore, erroneous diagnosis of the fuel storage device due to a temporary increase in the purge concentration is eliminated. Further, according to the first embodiment, it is possible to warn that the evaporated fuel has permeated the wall of the fuel tank.

In the first embodiment, the failure of the separation wall is diagnosed when the operating state of the internal combustion engine is stable (when the changes in the intake air amount, the engine load, and the engine speed are small) or when the oil supply pipe is used. When the learning of the purge concentration of the evaporated fuel introduced into the intake passage from the engine is completed (when the purge concentration is learned and the current purge concentration is determined), it is also possible to set the time. According to this, the failure diagnosis accuracy of the separation wall is improved.

Further, in addition to the failure diagnosis of the separation wall, the present invention is used to diagnose failures such as perforation failures and clogging failures in the fuel chamber, charcoal canister, and fuel vapor discharge pipe in the fuel supply pipe, and failures in opening and closing the purge control valve. You can also.

Next, a fuel storage device according to a second embodiment of the present invention will be described. Very little vaporized fuel permeates the walls of the fuel tank. Therefore, even when the diagnostic valve is shut off during the purging operation according to the first embodiment when the evaporated fuel is transmitted through the fuel tank wall, the purge concentration does not sufficiently decrease, and the evaporated fuel is transmitted through the fuel tank wall. It is difficult to diagnose what you are doing. Therefore, in the second embodiment, it is more reliably diagnosed that the evaporated fuel has passed through the wall of the fuel tank.

As shown in FIG. 9, in the second embodiment, a diagnostic valve 32 is attached to the evaporated fuel discharge pipe 28 in the canister between the purge control valve 29 and the charcoal canister 24. Therefore, the diagnostic valve 32 of the second embodiment is the air chamber 1
0 corresponds to a shutoff valve for stopping the introduction of fuel vapor into the intake passage. The diagnostic valve 32 is closed except when the failure diagnosis of the fuel storage device 1 is performed.

Further, a main charcoal canister 5 for temporarily adsorbing and holding the evaporated fuel when the evaporated fuel is present in the oil supply pipe is provided in the evaporated fuel discharge pipe 31 in the oil supply pipe.
0 is attached. Main charcoal canister 50
Is provided with activated carbon 51 therein. Activated carbon 51 fills the space in main charcoal canister 50 with discharge pipe side space 5.
2 and the atmosphere side space 53. The discharge pipe side space 52 directly communicates with the fuel supply pipe evaporative fuel discharge pipe 31. On the other hand, the atmosphere-side space 53 communicates directly with the atmosphere.

Further, a tank internal pressure control valve 54 for adjusting the pressure in the fuel tank 6 is provided in the fuel pipe evaporated fuel discharge pipe 31 (hereinafter referred to as a fuel pipe side discharge pipe) between the fuel pipe 11 and the main charcoal canister 50. Is attached. The tank internal pressure control valve 54 controls the pressure in the fuel supply pipe-side discharge pipe 31 so that the pressure in the fuel pipe-evaporated fuel discharge pipe 31 (hereinafter referred to as the discharge pipe-side discharge pipe) between the main charcoal canister 50 and the canister-evaporated fuel discharge pipe 28. The valve is opened when the pressure becomes higher by a predetermined first pressure than the pressure, and the oil supply pipe side discharge pipe 31 is opened.
Release pressure inside. The tank internal pressure control valve 54 opens when the pressure in the discharge pipe-side discharge pipe 31 becomes higher than the pressure in the oil supply pipe-side discharge pipe 31 by a predetermined second pressure. Release pressure inside. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, an outline of failure diagnosis of the fuel storage device of the second embodiment will be described. In the second embodiment, when the failure diagnosis is to be performed, after the diagnosis valve 32 is closed for a predetermined time, the purge is performed and the evaporated fuel adsorbed on the main charcoal canister 50 is sucked. The shut-off valve 32 is opened when the concentration of the evaporated fuel in the intake air becomes constant.

If no hole is formed in the wall of the fuel tank 6 and the evaporated fuel does not permeate the wall of the fuel tank 6, no evaporated fuel exists in the air chamber 10 and the charcoal canister 24. Therefore, even when the diagnostic valve 32 is opened, when the purge concentration is lower than the predetermined concentration or when the change in the purge concentration is smaller than the predetermined value, no hole is formed in the wall of the fuel tank 6 and It is diagnosed that the fuel vapor has not passed through the wall of the fuel tank 6 and the fuel storage device 1 is normal.

On the other hand, when the purge concentration is higher than the predetermined concentration after a predetermined time has elapsed since the opening of the diagnostic valve 32, a relatively large amount per unit time is stored in the air chamber 10. Therefore, a hole is opened in the wall of the fuel tank 6 and the fuel storage device 1 diagnoses as a failure based on the hole in the fuel tank wall.

Incidentally, the amount of fuel vapor generated per unit time generated in the air chamber 10 after the fuel in the fuel tank 6 passes through the wall of the fuel tank 6 is relatively small. However, according to the second embodiment, since the diagnostic valve 32 is closed for a predetermined time, a relatively large amount of fuel vapor is adsorbed in the charcoal canister 24. Therefore, when the diagnostic valve 32 is opened, the evaporated fuel mainly adsorbed in the charcoal canister 24 is introduced into the intake passage 30. Therefore, in the second embodiment, when the diagnostic valve 32 is opened and the purge concentration temporarily becomes higher than the predetermined concentration, and after the predetermined time has elapsed, the purge concentration is increased to the predetermined concentration. When the temperature becomes lower, the amount of evaporated fuel present in the air chamber 10 is relatively small, so that the fuel storage device 1 is diagnosed as a failure based on the permeation of the fuel. Thus, according to the second embodiment, it can be more reliably diagnosed that the evaporated fuel has passed through the wall of the fuel tank 6.

Next, a fuel storage device according to a third embodiment of the present invention will be described. When a hole is formed in the wall of the fuel tank in the fuel storage device of the first embodiment, fuel flows out of the hole and accumulates in the lowermost region of the fuel storage device. Therefore, more evaporated fuel is generated in the lower region than in the upper region in the fuel storage device. In the first embodiment, failure diagnosis is performed when the purge concentration becomes equal to or higher than a predetermined concentration. Therefore, when the fuel vapor to be introduced into the intake passage is collected from the upper region of the fuel storage device, the purge concentration may not increase to a predetermined concentration or more even if a hole is formed in the wall of the fuel tank. For this reason, in the first embodiment, there is a possibility that the failure of the fuel storage device cannot be diagnosed. Therefore, in the third embodiment, the failure of the fuel storage device can be reliably diagnosed.

As shown in FIG. 10, one end of the fuel supply pipe inside the fuel supply pipe 31 is connected to the charcoal canister 24 and opens into the air chamber side space 26 of the charcoal canister 24. One end of the fuel vapor discharge pipe 28 in the tank is connected to the bottom wall portion 39 of the housing 4 of the fuel storage device 1,
It opens to the lower space 41 in the fuel storage device 1. Further, instead of the air-fuel ratio sensor 36 of the first embodiment, an evaporated fuel concentration sensor (H) for directly detecting the amount of the fuel component in the intake passage 30 is used.
C sensor 40 is attached to surge tank 33 in intake passage 30. The fuel vapor concentration sensor 40 is connected to the electronic control unit 37. The other configuration and operation are the same as those of the first embodiment, and thus the description is omitted.

It should be noted that an oxygen concentration sensor for detecting the oxygen concentration in the intake air can be used instead of the evaporated fuel concentration sensor. In this case, it is determined that the lower the oxygen concentration in the intake air, the higher the evaporated fuel concentration in the intake air.

In the third embodiment, the fuel vapor to be introduced into the intake passage 30 is collected from the lower space 41 of the fuel storage device 1. When a hole is formed in the wall of the fuel tank 6, the fuel flowing out of the hole accumulates in the lowermost region of the fuel storage device 1. It is larger than the amount of fuel vapor in the upper space. Therefore, according to the third embodiment, the failure of the fuel storage device can be diagnosed more reliably than in the first embodiment.

Next, a fuel storage device according to a fourth embodiment of the present invention will be described. In the fourth embodiment, a failure diagnosis of the fuel storage device can be executed in a fuel storage device having a simpler structure than the fuel storage device of the first embodiment.

As shown in FIG. 11, in the fourth embodiment, the shut-off valve 19 of the first embodiment is omitted. Further, the fuel storage device of the fourth embodiment includes an alarm device 38 instead of the first alarm device 38a and the second alarm device 38b. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, an outline of the failure diagnosis of the fuel storage device according to the fourth embodiment will be described. In the fourth embodiment, a hole is formed in the wall of the fuel tank 6 when the number of times that the purge concentration becomes equal to or higher than the predetermined concentration becomes equal to or more than the predetermined number, and the fuel storage device 1 is broken down. Diagnose that there is. Thus, according to the fourth embodiment, the failure diagnosis of the fuel storage device can be performed in the fuel storage device having the simple configuration.

Next, the details of the failure diagnosis of the fuel storage device of the fourth embodiment will be described with reference to the flowchart of FIG. First, in step S200, it is determined whether the failure diagnosis execution flag F is set (F = “1”). The failure diagnosis execution flag of the fourth embodiment is the same as that of the first embodiment. In step S200, F
If "1", the fault diagnosis has been executed once, and the process is terminated. On the other hand, when F = “0”, the failure diagnosis has not been executed, and the process proceeds to step S202 to execute the failure diagnosis.

In step S202, it is determined whether or not the purge control valve 29 is open, that is, whether or not purging is being performed. When the purge control valve 29 is open, it is determined that the failure diagnosis can be performed because the purge is being performed, and the process proceeds to step S204 to calculate the purge concentration CP, and then proceeds to step S206. The method of calculating the purge concentration is the same as in the first embodiment. On the other hand, when the purge control valve 29 is open, it is determined that the failure diagnosis cannot be performed because the purge has not been performed, and the process proceeds to step S224 to clear the failure counter C in preparation for the next execution of the failure diagnosis. (C ← “0”), the process ends. The failure counter is counted up when it is diagnosed that the fuel storage device 1 has failed in the failure diagnosis. When the failure diagnosis cannot be executed as described above, there is a possibility that the fuel storage device 1 has failed. Cleared when diagnosed.

In step S206, the purge concentration CP is larger than the maximum purge concentration CPmax (CP> CPma).
x) is determined. When CP> CPmax, it is determined that a hole is formed in the wall of the fuel tank 6 and that there is a possibility that the fuel storage device 1 is out of order.
08 and counts up the failure counter C (C ←
C + 1), and then proceeds to step S210. On the other hand, CP ≦
When it is CPmax, it is determined that no hole is formed in the wall of the fuel tank 6, and the process proceeds to step S226.

In step S226, it is determined whether or not the failure counter C is larger than zero (C> 0). When C> 0, it is determined that the failure diagnosis should be terminated because the purge concentration has once become lower than the maximum purge concentration after exceeding the maximum purge concentration, and the flow advances to step S214 to set the failure diagnosis execution flag F. (F ← “1”), and then proceeds to step S216 to clear the failure counter C (C ← “0”), and then proceeds to step S218.

In step S210, the failure counter C is larger than a predetermined maximum value Cmax (C> Cma).
x) is determined. When C> Cmax, since the purge concentration does not become smaller than the maximum purge concentration even if the failure counter is counted by the predetermined maximum value after the purge concentration is determined to be larger than the maximum purge concentration in step S206, the fuel storage is performed. It is determined that the device 1 has failed, and the process proceeds to step S212 to count up the number of failure diagnoses N (N ← N + 1), and then proceeds to step S214 to set the failure diagnosis execution flag F (F
← “1”), and then proceeds to step S214 to clear the failure counter C (C ← “0”), and then to step S216
Proceed to. Note that the number of failure diagnoses N is the same as that of the first embodiment. On the other hand, in step S218, C ≦ Cma
If it is x, it is not possible to determine at this point that the fuel storage device 1 has failed, so the process ends.

In step S218, it is determined whether or not the failure diagnosis number N is larger than the maximum number Nmax (N> Nmax). When N> Nmax, the fuel storage device 1
Has been diagnosed as having failed more times than the maximum number of times, the process proceeds to step S220 to activate the alarm device 38,
The fact that the fuel storage device 1 is out of order is notified, and then the process proceeds to step S222 to clear the number N of fault diagnoses (N ←
“0”), and the process ends. On the other hand, if N ≦ Nmax in step S218, the process ends because it should not be determined that the fuel storage device 1 has failed at the present time.

Therefore, in the fourth embodiment, the purge control valve 29 corresponds to a shut-off valve for stopping the introduction of fuel vapor from the air chamber 10 into the intake passage.

Next, a failure diagnosis of the fuel storage device according to the fifth embodiment of the present invention will be described. Note that the fuel storage device of the fifth embodiment is the same as the first embodiment, and a description thereof will be omitted. In the first embodiment, the failure of the fuel storage device is diagnosed by comparing the purge concentration with a predetermined concentration. Diagnose the failure of the fuel storage device.

Next, the failure diagnosis of the fuel storage device according to the fifth embodiment will be described in detail with reference to the flowcharts of FIGS. First, in step S300, it is determined whether the failure diagnosis execution flag F is set (F = “1”). The failure diagnosis execution flag is the same as that of the first embodiment. In step S300, F = "1"
If, the failure diagnosis has been executed once, and the process is terminated. On the other hand, when F = "0", the failure diagnosis has not been executed, and the process proceeds to step S302 to execute the failure diagnosis.

In step S302 in FIG. 13, it is determined whether or not the purge control valve 29 is open, that is, whether or not purging is being performed. When the purge control valve 29 is open, it is determined that the failure diagnosis can be performed because the purge is being performed, and the routine proceeds to step S304, where the diagnostic valve 32 is operated.
Of the purge concentration CP1 before the valve is closed, and then, in step S
Proceeding to 306, the diagnostic valve 32 is closed, and then step S3
In step 08, the purge concentration CP2 after closing the diagnostic valve 32 is calculated, and then the flow proceeds to step S310. On the other hand, when the purge control valve 29 is closed, it is determined that the failure diagnosis cannot be executed because the purge is not executed, and the process proceeds to step S314 to clear the failure counter C in preparation for the next execution of the failure diagnosis. (C ← “0”), the process ends. The failure counter is the same as that of the first embodiment.

In step S310 of FIG.
The difference between the purge concentration CP1 before closing the valve and the purge concentration CP2 after closing the diagnostic valve 32 is the maximum purge concentration difference ΔCPmax.
It is determined whether it is larger than (CP1-CP2> ΔCPmax). When CP1−CP2> ΔCPmax, it is determined that a hole is formed in the wall of the fuel tank 6 and the fuel storage device 1 is out of order, and then, in step S3 in FIG.
Proceeding to 14, the failure diagnosis number N is counted up (N ←
N + 1), and then proceeds to step S320 to open the diagnostic valve 32, and then proceeds to step S322 to execute the failure counter C
Is cleared (C ← “0”), and the process proceeds to step S324 to set a failure diagnosis execution flag F (F ← “1”).
Proceed to step S326. Note that the number of failure diagnoses N is the same as that of the first embodiment. On the other hand, when CP1−CP2 ≦ ΔCPmax in step S310, it is determined that no hole is formed in the wall of the fuel tank 6, and FIG.
The process proceeds to step S332.

In step S326 in FIG. 14, it is determined whether or not the number of failure diagnoses N is greater than the maximum number of times Nmax (N> Nmax). If N> Nmax, it is diagnosed that the fuel storage device 1 has failed more times than the maximum number. Therefore, the process proceeds to step S328 and the first alarm device 38
is activated to notify that the fuel storage device 1 is faulty. Then, the process proceeds to step S330 to clear the number of fault diagnosis N (N ← “0”), and ends the processing. On the other hand, if N ≦ Nmax in step S326, the process ends because it should not be determined that the fuel storage device 1 has failed at the present time.

In step S332 of FIG.
The difference between the purge concentration CP1 before closing the valve and the purge concentration CP2 after closing the diagnostic valve 32 is the intermediate purge concentration difference ΔCPmid.
It is determined whether it is larger than (CP1-CP2> ΔCPmid). Note that the intermediate purge concentration difference is smaller than the maximum purge concentration difference. In step S332, CP1-CP2
> ΔCPmid, the fuel vapor is
Is determined to have passed through the wall of the fuel tank 6, the process proceeds to step S334, and the second alarm device 38b is operated to notify that the evaporated fuel has passed through the wall of the fuel tank 6.
Proceed to. The following steps have been described above and will not be described. When the process proceeds to step S326 after the activation of the second alarm device 38b, the failure diagnosis number N is not counted up, so that in step S326, N ≦ N.
Nmax is determined, and the process ends. On the other hand, when CP1−CP2 ≦ ΔCPmid in step S332, it is determined that the evaporated fuel has not passed through the wall of the fuel tank 6, and the process proceeds to step S320. The following steps have been described above and will not be described. When the process proceeds to step S326 after passing through step S332, the failure diagnosis number N is not counted up, and therefore, the process proceeds to step S32
In N6, it is always determined that N ≦ Nmax, and the process ends.

Next, a fuel storage device according to a sixth embodiment of the present invention will be described. In the second embodiment, when the failure diagnosis of the fuel storage device 1 is performed, the evaporated fuel in the fuel supply pipe 11 and the gas in the air chamber 10 are simultaneously introduced into the intake passage 30.
For this reason, when a relatively large amount of evaporative fuel is temporarily generated in the fuel supply pipe 11 or the like, the purge concentration becomes high even if no evaporative fuel exists in the air chamber 10. Therefore, there is a possibility that a malfunction of the fuel storage device 1 is misdiagnosed. Therefore, in the sixth embodiment, erroneous diagnosis of a failure of the fuel storage device is eliminated.

As shown in FIG. 15, in the sixth embodiment, the fuel supply pipe in the fuel supply pipe 31 is connected to the fuel supply pipe 28 in the tank via the three-way valve 55. The three-way valve 55 communicates the main charcoal canister 50 (and the intake passage 30) with the fuel supply pipe 11 except when performing a failure diagnosis of the fuel storage device 1. The air chamber 10 has a filter 60.
Is in communication with the atmosphere through Of course, the fuel vapor discharge pipe 28 in the tank is connected to the air chamber 10. The other configuration is the same as that of the second embodiment, and the description is omitted.

Next, an outline of the failure diagnosis of the fuel storage device according to the sixth embodiment will be described. In the sixth embodiment, when the failure diagnosis is to be performed, the three-way valve 55 is driven to drive the air chamber when a predetermined time has elapsed after the three-way valve 55 communicates with the main charcoal canister 50 and the intake passage 30. 1
0 communicates with the intake passage 30.

When the fuel storage device 1 is normal, no evaporated fuel exists in the air chamber 10. Therefore, when the purge concentration is zero when the inside of the air chamber 10 communicates with the intake passage 30, the fuel storage device 1 is diagnosed as normal.

On the other hand, when a failure has occurred in the fuel storage device 1 due to a hole in the fuel tank wall, the air chamber 10
There is a relatively large amount of fuel vapor inside. Air chamber 10
A relatively large amount of fuel vapor is generated in the air chamber 10 per unit time even after the fuel vapor in the chamber is removed. Therefore, when the purge concentration is higher than the predetermined purge concentration after a predetermined period of time has elapsed since the inside of the air chamber 10 communicated with the intake passage 30, the fuel storage device 1
It is diagnosed that a failure due to a hole in the fuel tank wall has occurred.

Further, when a failure occurs in the fuel storage device 1 due to the permeation of fuel, a relatively large amount of fuel vapor is present in the air chamber 10. After the fuel vapor in the air chamber 10 is removed, a relatively small amount of fuel vapor is generated in the air chamber 10 per unit time. Therefore, after the inside of the air chamber 10 is communicated with the intake passage 30, the purge concentration temporarily exceeds the predetermined purge concentration, and after the predetermined time has elapsed, the purge concentration is reduced to the predetermined purge concentration. When the concentration is lower than the concentration, it is diagnosed that a failure based on the permeation of the fuel has occurred in the fuel storage device 1.

According to the sixth embodiment, when the failure diagnosis of the fuel storage device is performed, only the air chamber is communicated with the intake passage. Therefore, the failure diagnosis of the fuel storage device is not affected by the evaporated fuel generated in the fuel supply pipe. Therefore, according to the sixth embodiment, the possibility of misdiagnosis of a failure of the fuel storage device is eliminated.

Next, the failure diagnosis of the fuel storage device of the sixth embodiment will be described in detail with reference to a flowchart. FIG.
In step S410, it is determined whether or not the failure diagnosis execution flag F has been reset (F = 0). The failure diagnosis execution flag F is the same as that of the first embodiment.
When F = 0, it is determined that the failure diagnosis has not been completed and the diagnosis has not been completed, and the process proceeds to step S412. On the other hand, F = 1
In the case of, it is determined that the failure diagnosis has been executed and the processing has ended, and the processing is ended.

In step S412, it is determined whether the purge control valve is open. When the purge control valve is open, it is determined that the failure diagnosis can be executed, and the process proceeds to step S414. On the other hand, when the purge control valve is closed, it is determined that the failure diagnosis cannot be executed or that the failure diagnosis cannot be continued even during the execution of the failure diagnosis, and the process proceeds to step S438 in FIG. The failure diagnosis execution flag F is set (F ← “1”), and the process proceeds to step S440 to switch the three-way valve that currently communicates the intake passage with the air chamber so that the intake passage communicates with the oil supply pipe. Next, the routine proceeds to step S442, where the three-way valve flag F1 is set.
Is reset (F1 ← “0”), and the process ends. The three-way valve flag F1 is a flag that is reset when the three-way valve communicates with the intake passage and the oil supply pipe, and is set when the three-way valve communicates with the intake passage and the air chamber.

In step S414, it is determined whether or not the three-way valve flag F1 has been reset (F1 = 0).
When F1 = 0, it is determined that the three-way valve communicates with the intake passage and the oil supply pipe, and in order to execute a failure diagnosis, the three-way valve is switched in step S416 to communicate the intake passage with the air chamber. In step S418, the three-way valve flag F1 is set (F1 ← “1”), and in step S4
Go to 20. On the other hand, when F1 = 1, it is determined that the three-way valve has already communicated the intake passage with the air chamber, and the process proceeds to step S420 without switching the three-way valve. Step S4
In step 20, the current purge concentration CP is calculated, and the flow advances to step S422 in FIG. The method of calculating the purge concentration CP is the same as that of the first embodiment.

In step S422 in FIG. 17, it is determined whether or not the failure diagnosis start flag F2 has been reset (F2 = 0). The failure diagnosis start flag F2 is a flag that is set immediately after the start of the failure diagnosis, and is reset when the failure diagnosis is executed and completed. Step S422
When F2 = 0, the fault diagnosis is started and it is determined that this is the first process, and the process proceeds to step S424. on the other hand,
When F2 = 1, it is determined that the process is the second or subsequent process after the failure diagnosis is started, and the diagnosis time t is counted up in step S430 (t ← “t + 1”), and the process proceeds to step S432. The diagnosis time t is reset when the failure diagnosis is started. Therefore, the diagnosis time t indicates the time that has elapsed since the start of the failure diagnosis.

In step S424, the current purge concentration C
P is larger than a predetermined purge concentration CP0 (CP
> CP0). When CP> CP0, it is determined that the purge concentration has exceeded a predetermined purge concentration CP0 immediately after the communication between the intake passage and the air chamber,
Proceeding to step S426, the failure diagnosis start flag F2 is set (F2 = “1”), then the diagnosis time t is reset (t = “0”) in step S428, and the process ends. On the other hand, when CP ≦ CP0, the purge concentration does not exceed the predetermined purge concentration CP0 immediately after communication between the intake passage and the air chamber, the fuel storage device is determined to be normal, and the failure diagnosis is terminated. To step S438
Proceed to.

In step S432, it is determined whether the diagnosis time t is longer than a predetermined diagnosis time t0 (t> t0). When t> t0, the process proceeds to step S434 in order to compare the purge concentration when a predetermined diagnosis time has elapsed since the start of the failure diagnosis with the predetermined purge concentration. When t ≦ t0, the process ends once.

In step S434, even when a predetermined diagnosis time has elapsed since the start of the failure diagnosis, the purge concentration CP is maintained at the predetermined purge concentration CP.
It is determined whether it is greater than (CP> CP0). CP
If> CP0, since the purge concentration is still higher than the predetermined purge concentration even after the predetermined diagnosis time has elapsed since the start of the failure diagnosis, it is determined that the fuel storage device has a perforated failure. Then, in step S436, the first alarm device is operated to notify the perforation failure, and the process proceeds to step S438 to end the failure diagnosis. On the other hand, when CP ≦ CP0, the purge concentration immediately after the start of the failure diagnosis was higher than the predetermined purge concentration, but when a predetermined diagnosis time has elapsed since the start of the failure diagnosis, the purge concentration becomes the predetermined value. Since the purge concentration is lower than the predetermined purge concentration, it is determined that the fuel storage device has a failure due to fuel permeation, and the second alarm device is activated in step S446 to notify the failure due to fuel permeation, and a step is performed to end the failure diagnosis. S438
Proceed to.

In step S438, the failure diagnosis execution flag F is set (F = "1"), and then step S440 is executed.
In step S3, the three-way valve is switched to connect the intake passage to the oil supply pipe. Then, in step S442, the three-way valve flag F1 is reset (F1 = "0"), and then in step S444, the failure diagnosis start flag F2 is reset ( F2 =
“0”), and the process ends.

Next, a fuel storage device according to a seventh embodiment of the present invention will be described with reference to FIG. The fuel storage device 1 of the present embodiment also includes a main charcoal canister 50 as in the second embodiment. In the present embodiment, unlike the second embodiment, the atmosphere side space 53 of the main charcoal canister 50 is connected to the air chamber 10. That is, the air chamber 10 is connected to the surge tank 33 of the intake passage 30 via the main charcoal canister 50. The air chamber 10 can be connected to the surge tank 33 by bypassing the main charcoal canister 50 by the bypass passage 42. The bypass passage 42 is connected to the in-canister evaporated fuel discharge pipe 28 via a bypass valve 43. The bypass valve 43 is disposed on the evaporative fuel discharge pipe 28 in the canister between the purge control valve 29 and the main charcoal canister 50. The bypass valve 43 is a three-way valve that selectively connects the air chamber 10 to the surge tank 33 via either the main charcoal canister 50 or the bypass passage 42.

In this embodiment, the air chamber 10 is connected to the connecting pipe 4.
4 is connected to the air filter 45 of the intake passage 30. An air introduction shutoff valve 46 for shutting off the connection pipe 44 is arranged in the connection pipe 44. In this embodiment, when the air introduction cutoff valve 46 is opened, the air chamber 10 is released to the atmosphere via the connection pipe 44, the air filter 45, and the intake passage 30. That is, when a negative pressure is introduced into the air chamber 10, air flows into the air chamber 10 via the intake passage 30, the air filter 45, and the connection pipe 44.

Incidentally, the bypass valve 43 and the air introduction cutoff valve 46 are connected to the electronic control unit 37, and the operation thereof is controlled by the electronic control unit 37. In the present embodiment, the second alarm device 38b of the second embodiment is omitted. The configuration other than the above is the same as that of the second embodiment. Next, a failure diagnosis according to the present embodiment will be described. In the present embodiment, the failure diagnosis is performed during the execution of the purge. During purging, the bypass valve 43 connects the air chamber 10 to the surge tank 33 via the main charcoal canister 50, and the air introduction cutoff valve 46 is opened. Therefore, during the execution of the purge, the evaporated fuel mainly adsorbed in the main charcoal canister 50 is purged into the surge tank 33, and air is released from the atmosphere through the connection pipe 44 into the air chamber 1
It flows into 0. The operation of the bypass valve 43 is switched when the purge is being performed as described above, and the air chamber 10 is connected to the surge tank 33 via the bypass passage 42. Thereby, the gas in the air chamber 10 is discharged into the surge tank 33 without passing through the main charcoal canister 50.
In this embodiment, the fuel vapor in the main charcoal canister 50 is not released into the surge tank 33 as described above,
When only the gas in the air chamber 10 is being discharged to the surge tank 33, the purge concentration CP is calculated, and the purge concentration C is calculated.
When P is higher than a predetermined purge concentration (hereinafter, referred to as a second purge concentration) CP2, it is diagnosed that there is a hole failure in the fuel tank wall.

As described above, in the present embodiment, only the gas in the air chamber is released into the surge tank at the time of failure diagnosis, so that the failure diagnosis can be performed accurately. In other words, the purge concentration calculated when the fuel vapor in the main charcoal canister or the fuel supply pipe is released into the surge tank during the failure diagnosis is affected by the fuel vapor released from the main charcoal canister or the fuel pipe into the surge tank. . For this reason, even when the calculated purge concentration is larger than a certain threshold value, there may be no perforation failure in the fuel tank wall. However, in this embodiment, since only the gas in the air chamber is released to the surge tank, the calculated purge concentration is not affected by the fuel vapor in the main charcoal caster or the fuel supply pipe. Therefore, according to the present embodiment, the calculated purge concentration is affected only by the fuel vapor in the air chamber, and therefore, a perforation failure in the fuel tank wall is accurately diagnosed.

Next, the failure diagnosis of this embodiment will be described in detail with reference to the flowcharts of FIGS. First, referring to FIG. 19, it is determined in step S500 whether the failure diagnosis execution flag F has been reset (F = 0). When it is determined in step S500 that F = 0, the process proceeds to step S501 to determine whether the purge control valve 29 has been opened, that is, whether the purge is being performed. Step S500
When it is determined in step S501 that the purge control valve 29 has been opened in step S501, it is determined that the failure diagnosis has not been performed yet and the engine operation state is in a state where the failure diagnosis can be performed. And step S
Proceeding to 502, a first failure diagnosis is performed. The first failure diagnosis is shown in detail in FIG. 20 and will be described later. On the other hand, when it is determined in step S500 that F = 1, it is determined that the failure diagnosis has already been performed, and when it is determined in step S501 that the purge control valve 29 has not been opened, the engine operation state has failed. It is determined that the diagnosis cannot be executed, and the process ends.

Next, the first failure diagnosis will be described in detail with reference to FIG. First, in step S601, the operation of the bypass valve 43 is switched. That is, the bypass valve 4 is provided so that the gas in the air chamber 10 bypasses the main charcoal canister 50 and is discharged into the surge tank 33.
3 is switched, and the process proceeds to step S602. In step S602, the progress of the first failure diagnosis routine is waited for a predetermined time. That is, the calculation of the purge concentration is on standby until the gas in the air chamber 10 is reflected on the purge concentration. Step S6 after the first failure diagnosis routine is waited for a predetermined time.
Proceeding to 03, the purge concentration CP is calculated. The standby process is performed according to the flowchart shown in FIG.

Next, in step S604, the purge concentration CP is larger than the second purge concentration CP2 (CP> CP
2) It is determined whether or not. In step S604, C
If it is determined that P> CP2, step S605
Then, the abnormality counter C2 is counted up, and then in step S606, the abnormality counter C2 is larger than a predetermined maximum value C2max (C2> C2ma).
x) is determined. In step S606, C
When it is determined that 2> C2max, it is determined that a perforation failure has occurred in the fuel tank wall, and step S607 is performed.
Then, the first alarm device 38a is operated, and the process proceeds to step S608. On the other hand, in step S606, C
When it is determined that 2 ≦ C2max, it is determined at this point that it should not be determined whether or not a perforation failure has occurred in the fuel tank wall, and the process returns to step S603. The abnormality counter C2 is used for the time when it is determined that there is a perforated failure in the fuel tank wall or when the surge tank 3
3 is a value representative of the accumulated amount of the evaporated fuel released.

On the other hand, in step S604, CP ≦ C
When it is determined to be P2, it is determined that there is no perforation failure in the fuel tank wall, and the process proceeds directly to step S608. In step S608, the abnormality counter C2 is reset in preparation for the next failure diagnosis, the operation of the bypass valve 43 is switched, that is, the air chamber 10 is connected to the surge tank 33 via the main charcoal canister 50, and the process ends.

Next, the standby processing according to the present embodiment will be described in detail with reference to FIG. First, in step S701, the standby time wt is counted up. Next, in step S702, it is determined whether the standby time wt is longer than a predetermined standby time Pwt (wt> Pwt). When it is determined in step S702 that wt> Pwt, it is determined that the process has been on standby for a predetermined time, and the flow advances to step S703 to reset the standby time wt. On the other hand, in step S702, wt ≦ Pwt
When it is determined that the relation is satisfied, the process returns to step S701, and this processing is repeated until it is determined in step S702 that wt> Pwt. Incidentally, in the present embodiment, the predetermined standby time Pwt is determined in step S60 in FIG.
In 1, the operation of the bypass valve 43 is switched, and only the gas in the air chamber 10 is released into the surge tank 33, and then the time required for the gas released from the air chamber 10 to be reflected in the purge concentration is obtained. Is set.

Next, a fuel storage device according to an eighth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the bypass passage 42, the bypass valve 43, and the first alarm device 38a of the seventh embodiment are eliminated. A pressure sensor 47 for detecting the pressure in the air chamber 10 is disposed in the upper part 2 of the fuel storage device 1. The pressure sensor 47 is connected to the electronic control device 37 and outputs a voltage corresponding to the pressure in the air chamber 10 to the electronic control device 37. In the eighth embodiment, a second alarm device 38b is provided. Second alarm device 38
b is connected to the electronic control unit 37. Other configurations are the same as in the seventh embodiment.

Next, a failure diagnosis according to the eighth embodiment will be described.
In the eighth embodiment, the fuel chamber 5 penetrates the wall of the fuel tank 6
The amount of evaporative fuel (hereinafter, permeated evaporative fuel) flowing out of the fuel chamber into the air chamber 10 and the amount of evaporative fuel (hereinafter, evaporative fuel in the oil supply pipe) generated in the fuel supply pipe 11 are relatively small and are adsorbed in the main charcoal canister 50. When the amount of the evaporated fuel is relatively small, a perforated failure diagnosis of the fuel tank wall is performed as in the seventh embodiment. That is, after the purge is first performed for a time sufficient to completely discharge the fuel vapor in the main charcoal canister 50, the purge control valve 29
And the air introduction cutoff valve 46 are closed, and the pressure in the air chamber 10 immediately before or immediately after the purge control valve 29 and the air introduction cutoff valve 46 are closed is detected by the pressure sensor 47 as an initial pressure. Next, when a predetermined time has elapsed since the detection of the initial pressure, the air chamber 10
Pressure (hereinafter, detected pressure) is detected. Here, when the amount of permeated fuel vapor and the amount of fuel vapor in the fuel supply pipe are relatively large, the detected pressure is relatively higher than the initial pressure. Therefore, when the differential pressure between the detected pressure and the initial pressure is smaller than the predetermined differential pressure, it is determined that the amount of the permeated fuel vapor and the amount of the fuel vapor in the fuel supply pipe are relatively small.

When the purge is performed for a time sufficient to completely discharge the fuel vapor in main charcoal canister 50, it is determined that the amount of fuel vapor adsorbed in main charcoal canister 50 is relatively small. . As described above, the diagnosis of the perforated hole in the fuel tank wall is performed under a certain condition, whereby accurate diagnosis can be performed without providing a bypass passage as in the seventh embodiment. That is, in the seventh embodiment, the bypass passage is used to prevent the fuel vapor in the main charcoal canister 50 from affecting the purge concentration during the failure diagnosis. On the other hand, if purging is performed for a predetermined time in a state where the amounts of the permeated fuel and the fuel oil in the fuel supply pipe are relatively small as in the present embodiment, as long as there is no hole in the fuel tank wall, the main charcoal is not damaged. The fuel vapor in the canister 50 has been completely discharged. That is, even if the bypass passage is not used, the influence of the fuel vapor in the main charcoal canister 50 on the purge concentration is extremely small. Therefore, according to the present embodiment, a failure diagnosis can be accurately performed without providing a bypass passage.

The failure diagnosis of the present embodiment is substantially the same as that of the seventh embodiment. In the seventh embodiment, the air introduction cutoff valve 46 is opened during the failure diagnosis. In the embodiment, the air introduction cutoff valve 46 is closed during the failure diagnosis. By doing so, no air is introduced into the air chamber 10 during the failure diagnosis.
The evaporated fuel flowing into the zero surge tank 33 is not diluted by air. For this reason, when a hole failure occurs in the wall of the fuel tank 76, the change in purge concentration is large, and failure diagnosis can be performed accurately.

Next, the failure diagnosis of the eighth embodiment will be described in detail with reference to the flowcharts of FIGS. First, referring to FIG. 23, it is determined in step S800 whether the failure diagnosis execution flag F has been reset (F = 0). When it is determined in step S800 that F = 0, the process proceeds to step S801, and it is determined whether the purge control valve 29 is opened, that is, whether the purge is being performed. Step S80
When F is 0 at 0 and it is determined in step S801 that the purge control valve 29 has been opened, it is determined that the failure diagnosis has not been performed yet and the engine operating state is in a state where the failure diagnosis can be performed. The process proceeds to step S802, where the second failure diagnosis is performed. In the present embodiment, after the second failure diagnosis is executed in preparation for the next second failure diagnosis, the process proceeds to step S803, and the third failure diagnosis is executed. The second failure diagnosis is shown in detail in FIG. 24, and the third failure diagnosis is shown in FIG. 25 in detail.

When it is determined in step S800 that F = 1, it is determined that the failure diagnosis has already been performed.
When it is determined in step S801 that the purge control valve 29 has not been opened, it is determined that the engine operation state is in a state where failure diagnosis cannot be performed, and the process is terminated. Next, the second failure diagnosis will be described in detail with reference to FIG. First, in step S901, it is determined whether or not the fuel vapor flag F3 is set (F3 = 1). The evaporative fuel flag F3 is a flag that is set when the amount of permeated evaporative fuel and the amount of fuel vapor in the fuel supply pipe is smaller than a predetermined amount in a third failure diagnosis to be described later, and is reset when the amount is larger than the predetermined amount. However, when the third failure diagnosis has never been executed, the evaporated fuel flag F3 is set. When it is determined in step S901 that F3 = 1, that is, when the amount of permeated fuel vapor and the amount of fuel vapor in the fuel supply pipe are relatively small, it is determined that the diagnosis of the hole in the fuel tank wall can be performed, and the process proceeds to step S902. On the other hand, when it is determined in step S901 that F3 = 0, that is, when the amount of permeated evaporated fuel and the amount of evaporated fuel in the fuel supply pipe are relatively large, it is determined that the failure diagnosis of the hole in the fuel tank wall cannot be performed, and the process ends. I do.

In step S902, it is determined whether the purging has been continuously performed for a predetermined time. When it is determined that the purging has been continuously performed for a predetermined time, it is determined that the fuel vapor in the main charcoal canister 50 has been completely removed, and the process proceeds to step S903, where the air introduction shut-off valve 46 is reset. The valve is closed, and the flow advances to step S904 to execute a standby process similar to the standby process in FIG. Note that the predetermined standby time Pwt in the standby process in step S904 is necessary for the gas released from the air chamber 10 to be reflected in the purge concentration after the air introduction cutoff valve 46 is closed in step S903. Set to time.

Next, the routine proceeds to step S905, where the purge concentration CP is calculated. In step S906, the purge concentration CP is larger than the second purge concentration CP2 (CP> CP).
2) It is determined whether or not. In step S906, C
If it is determined that P> CP2, step S907
Then, the abnormality counter C2 is counted up, and then in step S908, the abnormality counter C2 is larger than a predetermined maximum value C2max (C2> C2ma).
x) is determined. In step S908, C
When it is determined that 2> C2max, it is determined that a perforation failure has occurred in the fuel tank wall, and step S909 is performed.
And the second alarm device 38b is operated, and the process proceeds to step S9.
Go to 10. On the other hand, in step S908, C2 ≦ C
If it is determined to be 2max, it is determined at this point that it should not be determined whether or not a perforation failure has occurred in the fuel tank wall, and the process returns to step S905.

By the way, in step S904, CP ≦
When it is determined to be CP2, it is determined that there is no perforation failure in the fuel tank wall, and the process proceeds directly to step S910. In step S910, the abnormality counter C2 is reset in preparation for the next failure diagnosis, the air introduction cutoff valve 46 is opened, and the process ends. Next, the third failure diagnosis will be described in detail with reference to FIG. First, in step S1001, it is determined whether the second alarm device 38b is not operating. When it is determined that the second alarm device 38b is not operating, there is no perforation failure in the fuel tank wall at the present time, and a third failure diagnosis, that is, a diagnosis as to whether the amount of permeated fuel vapor and the amount of fuel vapor in the fuel supply pipe is small. Can be executed, and the process proceeds to step S1002. Of course step S1
When it is determined in 001 that the second alarm device 38b is operating, it is determined that the third failure diagnosis cannot be executed, and the process ends.

In step S1002, the purge control valve 29
Is closed, then in step S1003, the air introduction cutoff valve 46 is closed, and then in step S1004, the pressure in the air chamber 10 is
7 is detected as the initial pressure Pa0. Next, in step S1005, a standby process similar to the standby process of FIG. 21 is executed. Note that the predetermined standby time Pwt in the standby processing in step S1005 is equal to the predetermined standby time Pwt in step S1005.
2 and in step S1003, the purge control valve 29
After the air introduction cutoff valve 46 is closed, the time required for the pressure in the air chamber 10 to change sufficiently by the permeated fuel vapor and the fuel oil vaporized fuel to perform the third failure diagnosis is set. .

Next, in step S1006, the pressure in the air chamber 10 is detected by the pressure sensor 47 as the detected pressure Pa1, and in step S1007, the detected pressure P
a1 is equal to a predetermined pressure difference Δ
It is determined whether it is smaller than PPa (Pa1−Pa0 <ΔPPa). In step S1007, Pa1-P
When it is determined that a0 <ΔPPa, it is determined that the permeated evaporated fuel amount and the fuel supply tube evaporated fuel amount are relatively small, the flow proceeds to step S1008, the evaporated fuel flag F3 is set, and the flow proceeds to step S1009. On the other hand, step S1
If it is determined in 007 that Pa1−Pa0 ≧ ΔPPa, it is determined that the amount of permeated fuel vapor and the amount of fuel vapor in the fuel supply pipe are relatively large.

At step S1009, the purge control valve 29
Is opened, and then in step S1010, the air introduction cutoff valve 46 is opened. Note that FIG.
In the flowcharts of FIGS. 3 to 25, the third failure diagnosis is executed for the next second failure diagnosis when there is no perforated failure in the fuel tank wall in the second failure diagnosis this time. However, the third failure diagnosis may be executed as a separate routine from the second failure diagnosis.

Next, a fuel storage device according to a ninth embodiment will be described with reference to FIG. The fuel storage device 1 according to the ninth embodiment has a fourth alarm device 38d and a fifth alarm device 38e without the first alarm device 38a according to the seventh embodiment. Connected to. A pressure sensor 47 for detecting the pressure in the air chamber 10 is disposed in the upper part 2 of the fuel storage device 1. The pressure sensor 47 is connected to the electronic control device 37,
The voltage corresponding to the pressure in the air chamber 10 is stored in the electronic control unit 37.
Output to Other configurations are the same as those of the seventh embodiment.

Next, the failure diagnosis of this embodiment will be described. In the present embodiment, in addition to the fourth failure diagnosis for diagnosing a perforation failure in the fuel tank wall, perforations in the wall forming a space for evaporative fuel to flow, for example, the upper part 2 and the lower part of the fuel storage device 1 A fifth failure diagnosis for diagnosing a perforation failure in the wall of No. 3 and a perforation failure in each evaporative fuel discharge pipe or the like is performed. Specifically, after closing the air introduction cutoff valve 46 first, a fourth failure diagnosis similar to the first failure diagnosis of the seventh embodiment is executed,
Prevention of dilution of the evaporated fuel due to the fresh air flowing into the air chamber 10 makes a highly accurate determination. In the fourth failure diagnosis, when it is determined that there is no perforated failure in the fuel tank wall, the fifth failure diagnosis is executed. In the fifth failure diagnosis, when it is determined in the fourth failure diagnosis that there is no perforated failure in the fuel tank wall, purging is continued with the air introduction shut-off valve 46 being closed during the fourth failure diagnosis, and the air chamber 10 is opened. The internal pressure of the air chamber is reduced to a negative pressure, and then the purge control valve 29 is closed to open
0, and the purge control valve 2 is closed.
If the pressure in the air chamber 10 has risen above a predetermined value when a predetermined time has elapsed after the closing of the valve 9, a hole is formed in the wall of the fuel storage device 1 other than the fuel tank 6. Diagnose that there is a failure.

According to the present embodiment, the failure of the hole in the fuel tank wall and the failure of the hole in the wall of the fuel storage device other than the fuel tank wall are diagnosed in one process. Therefore, two types of failure diagnosis can be performed in a short time. Purge control valve 2
The time during which the valve 9 is opened to interrupt the purge is also shortened. Next, the failure diagnosis according to the ninth embodiment will be described in detail with reference to the flowcharts of FIGS. First, referring to FIG. 27, in step S1100, the failure diagnosis execution flag F
Is reset (F = 0).
When F = 0 in step S1100, the process proceeds to step S1101, and it is determined whether the purge control valve 29 is opened, that is, whether the purge is being performed. When it is determined in step S1100 that F = 0 and in step S1101 that the purge control valve 29 has been opened, the failure diagnosis has not been performed yet, and the engine operating state is in a state where the failure diagnosis can be performed. The process proceeds to step S1101a to close the air introduction cutoff valve 46, and then to step S1102.
Then, the fourth failure diagnosis is executed. In the present embodiment, after the fourth failure diagnosis is performed, the process proceeds to step S1103 to perform the fifth failure diagnosis, and thereafter, the process proceeds to step S1103.
Proceeding to 103a, the air introduction cutoff valve 46 is opened.
The fourth failure diagnosis is shown in FIG. 28 and the fifth failure diagnosis is shown in FIG. 29 in detail.

When it is determined in step S1100 that F = 1, it is determined that the failure diagnosis has already been performed, and in step S1101, the purge control valve 2 is determined.
When it is determined that the valve 9 has not been opened, it is determined that the engine operation state is in a state where the failure diagnosis cannot be executed, and the process is terminated. Next, the fourth failure diagnosis will be described in detail with reference to FIG. First, step S1201
, The operation of the bypass valve 43 is switched. That is, the operation of the bypass valve 43 is switched so that the gas in the air chamber 10 is discharged into the surge tank 33 bypassing the main charcoal canister 50, and step S is performed.
Proceed to 1203.

In step S1203, the purge concentration CP is calculated. In step S1204, the purge concentration CP is calculated.
Is larger than the second purge concentration CP2 (CP> CP2). CP in step S1204>
If it is determined that it is CP2, the process proceeds to step S1205, where the abnormality counter C2 is counted up. Then, in step S1206, the abnormality counter C2 is larger than a predetermined maximum value C2max (C2> C2ma).
x) is determined. If it is determined in step S1206 that C2> C2max, it is determined that a perforation failure has occurred in the fuel tank wall, and step S12
In step 07, the fourth alarm device 38d is operated, and the flow advances to step S1208. On the other hand, when it is determined in step S1206 that C2 ≦ C2max, it is determined at this point that a hole opening failure in the fuel tank wall should not be determined, and the process returns to step S1203.

By the way, in step S1204, the CP
When it is determined that ≤CP2, it is determined that no perforation failure has occurred in the fuel tank wall, and the flow directly proceeds to step S1208. In step S1208, the abnormality counter C2 is reset in preparation for the next failure diagnosis, and then in step S1209, the operation of the bypass valve 43 is switched. That is, the air chamber 10 is connected to the surge tank 33 via the main charcoal canister 50, and the process ends.

Next, the fifth failure diagnosis will be described in detail with reference to FIG. First, in step S1301, it is determined whether the fourth alarm device 38d is not operating. When it is determined that the fourth alarm device 38d is not operating, there is no perforation failure in the fuel tank wall, and the fifth failure diagnosis, that is, the perforation failure diagnosis on the fuel storage device wall other than the fuel tank 6 wall is performed. It is determined that it should be performed, and step S13
Go to 03. Of course, when it is determined in step S1301 that the fourth alarm device 38d is operating, it is determined that it is not necessary to execute the fifth failure diagnosis, and the process ends.

In step S1303, the pressure in the air chamber 10 is detected by the pressure sensor 47 as the initial pressure Pa0. Next, in step S1304, the initial pressure Pa
0 is smaller than a predetermined negative pressure PPan (Pa0 <
PPan) is determined. If it is determined in step S1304 that Pa0 <PPan, the process advances to step S1305. On the other hand, if it is determined in step S1304 that Pa0 ≧ PPan, the process returns to step S1303, and in step S1304, Pa0
This routine is repeated until it is determined that 0 <PPan.

At step S1305, the purge control valve 29
Is closed, and then in step S1306, a standby process similar to the standby process of FIG. 21 is executed. still,
The predetermined standby time Pwt in the standby process in step S1306 is necessary for the pressure in the air chamber 10 to change sufficiently to execute the fifth failure diagnosis after the purge control valve 29 is closed in step S1305. Time is set.

Next, in step S1307, the pressure in the air chamber 10 is detected as the detected pressure Pa1 by the pressure sensor 47, and in step S1308, the detected pressure P is detected.
a1 is equal to a predetermined pressure difference Δ
It is determined whether it is larger than PPa (Pa1−Pa0> ΔPPa). In step S1308, Pa1-P
When it is determined that a0> ΔPPa, the fuel tank 6
It is determined that a perforation failure has occurred on the wall of the fuel storage device other than the wall of the fifth alarm device, and the process proceeds to step S1309 to proceed to the fifth alarm device 3
8e is operated, and the process proceeds to step S1310. On the other hand, when it is determined in step S1308 that Pa1−Pa0 ≦ ΔPa, it is determined that a hole failure has not occurred in the walls of the fuel storage device other than the wall of the fuel tank 6, and the process directly proceeds to step S1310.

In step S1310, the purge control valve 29
Is opened.

[0122]

According to the first to ninth aspects, the presence or absence of the fuel component in the air chamber of the fuel storage device can be detected based on the amount of the fuel component in the internal combustion engine after the opening and closing of the shut-off valve. For this reason, when there is a fuel component in the air chamber, it can be diagnosed that the separation wall of the fuel storage device has failed.

[Brief description of the drawings]

FIG. 1 is a view showing a fuel storage device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a fuel tank according to the first embodiment.

FIG. 3 is a sectional perspective view of the fuel tank taken along line III-III in FIG. 2;

FIG. 4 is a sectional perspective view similar to FIG. 3, showing the fuel tank in an expanded state.

FIG. 5 is a sectional perspective view similar to FIG. 3 showing the fuel tank in a recessed state.

FIG. 6 is a part of a flowchart of a failure diagnosis of the fuel storage device of the first embodiment.

FIG. 7 is a part of a flowchart of a failure diagnosis of the fuel storage device of the first embodiment.

FIG. 8 is a part of a flowchart of a failure diagnosis of the fuel storage device of the first embodiment.

FIG. 9 is a view showing a fuel storage device according to a second embodiment of the present invention.

FIG. 10 is a view showing a fuel storage device according to a third embodiment of the present invention.

FIG. 11 is a view showing a fuel storage device according to a fourth embodiment of the present invention.

FIG. 12 is a flowchart of a failure diagnosis of a fuel storage device according to a fourth embodiment.

FIG. 13 is a part of a flowchart of a failure diagnosis of the fuel storage device of the fifth embodiment.

FIG. 14 is a part of a flowchart of a failure diagnosis of the fuel storage device of the fifth embodiment.

FIG. 15 is a view showing a fuel storage device according to a sixth embodiment.

FIG. 16 is a part of a flowchart of a failure diagnosis of the fuel storage device of the sixth embodiment.

FIG. 17 is a part of a flowchart of a failure diagnosis of the fuel storage device of the sixth embodiment.

FIG. 18 is a view showing a fuel storage device according to a seventh embodiment.

FIG. 19 is a flowchart of a failure diagnosis according to a seventh embodiment.

FIG. 20 is a flowchart of a first failure diagnosis according to a seventh embodiment.

FIG. 21 is a flowchart of a standby process according to a seventh embodiment.

FIG. 22 is a view showing a fuel storage device according to an eighth embodiment.

FIG. 23 is a flowchart of a failure diagnosis according to the eighth embodiment.

FIG. 24 is a flowchart of a second failure diagnosis according to the eighth embodiment.

FIG. 25 is a flowchart of a third failure diagnosis of the eighth embodiment.

FIG. 26 is a view showing a fuel storage device according to a ninth embodiment.

FIG. 27 is a flowchart of a failure diagnosis according to a ninth embodiment.

FIG. 28 is a flowchart of a fourth failure diagnosis according to the ninth embodiment.

FIG. 29 is a flowchart of a fifth failure diagnosis according to the ninth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel storage device 6 ... Fuel tank 29 ... Purge control valve 32 ... Diagnostic valve 36 ... Air-fuel ratio sensor 37 ... Electronic control device

Continued on the front page (72) Inventor Naoya Takagi 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Hidekazu Sasaki 1 Toyota Town, Toyota City, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation

Claims (9)

[Claims] 1. A fuel storage device for storing fuel, comprising a separation wall for separating an internal space of the fuel storage device into a fuel chamber and an air chamber, wherein the separation wall is provided in the fuel chamber. In the failure diagnosis device for a fuel storage device that is deformable in the fuel storage device in accordance with the amount, a gas introduction passage for introducing gas in the air chamber into an intake passage of an internal combustion engine, and a gas introduction passage. A shutoff valve for shutting off, a fuel component amount detecting means for detecting a fuel component amount in the internal combustion engine after the shutoff valve is opened or closed, and a fuel detected by the fuel component amount detecting means. Detecting a fuel component in the gas introduced into the intake passage based on the component amount,
A failure diagnosis means for diagnosing that the separation wall has failed when detecting the presence of a fuel component in the gas. 2. The failure diagnosis unit detects a fuel component in the gas introduced into the intake passage by comparing the fuel component amount detected by the fuel component detection unit with a predetermined fuel component amount. The failure diagnosis device for a fuel storage device according to claim 1, wherein 3. The fuel component amount detecting means detects the fuel component amount in the internal combustion engine before the opening or closing of the shutoff valve, and the failure diagnosis means detects the fuel component amount by the fuel component amount detecting means. 2. The fuel supply system according to claim 1, wherein a fuel component in the gas introduced into the intake passage is detected based on a change in a fuel component amount in the internal combustion engine before and after opening or closing the shutoff valve. 3. Failure diagnosis device for fuel storage device. 4. The failure diagnosis device for a fuel storage device according to claim 1, wherein said fuel component amount detection means is disposed in said intake passage and detects an amount of a fuel component in intake air. 5. The fuel component amount detecting means includes an air-fuel ratio sensor disposed in an exhaust passage of the internal combustion engine, and detects an amount of fuel component in the internal combustion engine based on an air-fuel ratio in exhaust gas detected by the air-fuel ratio sensor. The failure diagnosis device for a fuel storage device according to claim 1, wherein the amount of the fuel component is detected. 6. The gas introduction passage further introduces gas in the fuel chamber into an intake passage of an internal combustion engine, and the shut-off valve stops introduction of gas from one of the fuel chamber and the air chamber into the intake passage. The failure diagnosis device for a fuel storage device according to claim 1, wherein 7. The failure diagnosis means diagnoses that a hole is formed in the separation membrane when the fuel component amount in the internal combustion engine after opening or closing the shutoff valve is larger than a predetermined fuel component amount. When the fuel component amount in the internal combustion engine after the opening or closing of the shut-off valve is smaller than the predetermined fuel component amount, it is diagnosed that the fuel in the fuel chamber has permeated the separation membrane. The failure diagnosis device for a fuel storage device according to claim 1, wherein: 8. The failure of the fuel storage device according to claim 1, wherein the introduction of air into the air chamber is blocked while the failure diagnosis means diagnoses a failure of the separation wall. Diagnostic device. 9. The failure diagnosis means shuts off the gas introduction passage by the shutoff valve after the gas in the air chamber is introduced into the intake passage via the gas introduction passage, and disconnects the gas introduction passage. The failure diagnosis device for a fuel storage device according to claim 1, wherein a failure of the fuel storage device is diagnosed based on a pressure in the air chamber after being shut off by a shutoff valve.