JP2001123894A - Fuel-storing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To insure a sufficient time to purge fuel adsorbed at a canister. SOLUTION: A fuel tank 22 is provided to be partitioned into a fuel chamber 28 and an air chamber 30 by a bladder film 26, and after the vaporized fuel generated in a fuel tank 22 is adsorbed by a canister 62, it is purged toward an intake passage 34. By closing an evaporator system with a negative pressure introduced, an evaporator system hole is detected. Furthermore, by directly purging gas in the air chamber 30 in the intake passage 34 by bypass of is through the canister 62, a bladder film hole is detected. When a negative pressure is introduced through detection of the evaporator hole, detection of the bladder hole is executed. In this case, by overlapping the timing at which fuel is not purged from the canister 62 through detection of the evaporator system hole with a timing, at which fuel is not purged from the canister 62 through detection of the bladder film hole, a timing in which fuel adsorbed to the canister 62 is purged, is prevented from being shortened sharply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel storage device, and more particularly, to purging an evaporative fuel generated in a fuel tank separated by a separation membrane into a fuel chamber and an air chamber into an intake passage of an internal combustion engine. The present invention relates to a fuel storage device.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 10-1844
As disclosed in Japanese Patent No. 64, in order to prevent evaporative fuel (vapor) generated in the fuel tank from being released into the atmosphere,
2. Description of the Related Art An evaporative fuel processing apparatus for purging evaporative fuel in a fuel tank toward an intake passage is known. The above fuel tank is
In order to reduce the generation of fuel vapor, a deformable separation membrane for sealingly separating the internal space into a fuel chamber and an air chamber is provided. Further, the above-described evaporated fuel processing device includes a canister that adsorbs the evaporated fuel from the fuel tank, and a purge control valve that controls an open / close state between the canister and the intake passage. In such a device, when the purge control valve is opened during operation of the internal combustion engine, a negative pressure is introduced into the intake passage, so that air flows from the fuel tank toward the intake passage. In this case, the fuel adsorbed in the canister is purged toward the intake passage with the flow of air. Therefore,
According to the above-described evaporative fuel processing device, the evaporative fuel generated in the fuel tank can be supplied to the internal combustion engine as fuel without being released into the atmosphere.

[0003] By the way, if a hole is made in the separation membrane provided in the fuel tank as described above, there is a possibility that a part of the evaporated fuel is released into the atmosphere due to the fuel leaking into the air chamber. Therefore, in a fuel tank having a separation membrane, it is necessary to diagnose whether or not a hole is formed in the separation membrane. The concentration of the fuel vapor in the air chamber is small when no hole is formed in the separation membrane, and is large when the hole is formed in the separation membrane. Therefore, as a method of diagnosing whether or not a hole is formed in the separation membrane, the purging of fuel from the canister to the intake passage is interrupted, and gas in the air chamber is directly purged toward the intake passage. It is conceivable to detect the gas concentration (hereinafter referred to as vapor concentration). According to this method, when the vapor concentration is high, it can be determined that a hole is formed in the separation membrane, and when the vapor concentration is low, it is possible to determine that no hole is formed in the separation membrane.

[0004]

When diagnosing whether or not a hole is formed in the separation membrane using the above-described method, it is necessary to interrupt the purging of fuel from the canister to the intake passage as described above. For this reason, a period in which the fuel adsorbed in the canister can be purged (hereinafter, referred to as a purgeable period) is shortened.

[0005] The present invention has been made in view of the above points, and it is an object of the present invention to provide a fuel storage device capable of sufficiently securing a period for purging fuel adsorbed in a canister.

[0006]

The above object is achieved by the present invention.
As described in the above, a fuel tank separated into a fuel chamber and an air chamber by a separation membrane, an evaporative gas treatment mechanism for purging evaporated fuel of the fuel tank to an intake passage via a canister, and a negative pressure in the evaporative system. A hole detecting means for detecting a hole in the evaporation system by filling, and a gas in the air chamber bypassing the canister and directly purging the gas into the intake passage to thereby allow the gas to flow from the fuel chamber to the air chamber. A fuel leak detecting means for detecting a fuel leak, wherein the fuel leak detecting means detects the fuel leak when the negative pressure is introduced by the hole detecting means. Achieved.

In the present invention, a hole in the evaporative system is detected by filling the evaporative system with a negative pressure, and gas in the air chamber of the fuel tank is directly purged into the intake passage by bypassing the canister. Fuel leakage from the fuel chamber to the air chamber is detected. In the process of filling the evaporative system with a negative pressure in order to detect a hole in the evaporative system, fresh air does not flow into the evaporative system, so that the fuel adsorbed on the canister cannot be effectively purged toward the intake passage. . For this reason, if it is assumed that the detection of the hole in the evaporation system and the detection of the fuel leak from the fuel chamber to the air chamber are performed separately and independently, a period during which the fuel adsorbed by the canister can be purged toward the intake passage is assumed. Becomes shorter.

Therefore, in the present invention, the detection of fuel leakage from the fuel chamber to the air chamber is performed when a negative pressure is introduced into the evaporation system in order to detect a hole in the evaporation system. In this case, since the detection of the fuel leakage and the detection of the hole in the evaporation system are performed at the same time, the period in which the fuel adsorbed in the canister can be purged is not significantly shortened. Therefore, according to the present invention, it is possible to sufficiently secure a period for purging the fuel adsorbed on the canister.

[0009] The object of the present invention is as described in claim 2.
A fuel tank separated into a fuel chamber and an air chamber by a separation membrane, and an evaporative gas treatment mechanism for purging evaporated fuel from the fuel tank to an intake passage via a canister, wherein a predetermined condition is satisfied. In a fuel storage device capable of executing a communication passage switching control for interrupting a communication passage between a canister and the intake passage, when a stop condition of the internal combustion engine is satisfied, a period in which the communication passage is shut off after the stop condition is satisfied. The fuel storage device is provided with engine control means for stopping the internal combustion engine after elapse of.

In the present invention, the communication passage between the canister and the intake passage is cut off when a predetermined condition is satisfied. During the period in which the communication passage is shut off, the fuel adsorbed in the canister cannot be purged toward the intake passage. Therefore, in the present invention, when the stop condition of the internal combustion engine is satisfied, the internal combustion engine is stopped after the stop condition is satisfied and after the communication passage shutoff period has elapsed. In this case, since the operation of the internal combustion engine is continued for a long period of time only for the above-mentioned communication passage interruption period, it becomes possible to purge the evaporated fuel toward the intake passage. As described above, according to the present invention, the fuel adsorbed in the canister is purged longer than the case where the internal combustion engine is stopped immediately after the stop condition of the internal combustion engine is satisfied, for a longer period of time when the communication path is shut off. be able to. Therefore, according to the present invention, it is possible to sufficiently secure a period for purging the fuel adsorbed on the canister.

According to a third aspect of the present invention, in the fuel storage device according to the first aspect, a purge control valve provided in a communication path between the canister and the intake passage, and an air chamber for detecting an internal pressure of the air chamber. A fuel storage device, comprising: a pressure detection unit; and an opening control unit that controls an opening of the purge control valve based on a detection result of the air chamber pressure detection unit. It is effective in properly introducing the negative pressure to the evaporation system even when it changes.

In the present invention, the internal pressure of the air chamber changes with the fluctuation of the volume of the air chamber. For this reason, even if the purge control valve provided in the communication passage between the canister and the intake passage is opened to the same opening, the flow rate of the gas flowing through the communication passage does not become the same, and the evaporative system is not used. The time for introducing the negative pressure may not be the desired time. Therefore, in the present invention, the opening of the purge control valve is controlled based on the internal pressure of the air chamber of the fuel tank. For this reason, according to the present invention, even when the internal pressure of the air chamber changes, the speed at which the negative pressure is introduced into the evaporative system can always be kept constant.

Further, as described in claim 4, claim 1 is
The fuel storage device according to claim 1, further comprising: a switching valve that switches between a conduction state between the intake passage and the canister and a conduction state between the intake passage and the air chamber, and when the negative pressure is introduced by the hole detection means, Diagnosing a failure of the switching valve based on a comparison result of the evaporated fuel concentration on the downstream side of the switching valve before and after the switching of the switching valve, wherein the fuel storage device detects the failure of the switching valve. This is effective in preventing the purgeable period of the fuel adsorbed in the canister from being significantly shortened.

In the present invention, there is provided a switching valve for switching between a conduction state between the intake passage and the canister and a conduction state between the intake passage and the air chamber. The failure of the switching valve is diagnosed based on the comparison result of the evaporated fuel concentration on the downstream side before and after the switching of the switching valve. Thus, when diagnosing a failure of the switching valve, the canister may not be able to communicate with the intake passage. Therefore, if the failure of the switching valve is diagnosed at an arbitrary time, there is a possibility that the period in which the fuel adsorbed in the canister can be purged toward the intake passage may be shortened.

Therefore, in the present invention, the failure of the switching valve is diagnosed when a negative pressure is introduced into the evaporation system in order to detect a hole in the evaporation system. in this case,
By simultaneously performing the diagnosis of the failure of the switching valve and the detection of a hole in the evaporation system, it is possible to prevent the period in which the fuel adsorbed in the canister can be purged from becoming short. Therefore, according to the present invention, it is possible to sufficiently secure a period for purging the fuel adsorbed on the canister.

[0016]

FIG. 1 shows a system configuration diagram of a fuel storage device according to a first embodiment of the present invention. The system according to the present embodiment includes an electronic control unit (hereinafter, referred to as an ECU) 2
0, which is controlled by the ECU 20. As shown in FIG. 1, the fuel storage device of the present embodiment includes a fuel tank 22 whose outer periphery is covered with a ferrous member, and discharges fuel vapor generated in the fuel tank 22 to the atmosphere. Instead, an evaporative gas purge system for supplying fuel to the internal combustion engine 24 is provided. The fuel tank 22 is separated by a bladder membrane 26 into a fuel chamber 28 in which fuel is stored and an air chamber 30 in which air is filled. Bladder film 2
6 is made of a member such as an elastic resin,
The fuel tank 22 according to the amount of fuel stored in the fuel chamber 28
Can expand and contract within.

In the air chamber 30, an air cleaner 3 disposed in an intake passage 34 of the internal combustion engine 24 via an introduction passage 32 is provided.
6 are in communication. The air cleaner 36 is used for the internal combustion engine 24.
It has a function of filtering air sucked into the air. A throttle valve 38 is provided downstream of the air cleaner 36. In the vicinity of the throttle valve 38, a throttle opening sensor 40 is provided. The throttle opening sensor 40 outputs an electric signal corresponding to the opening of the throttle valve 38 to the ECU 20. The ECU 20
Based on the output signal of the throttle opening sensor 40, the opening TA of the throttle valve 38 (hereinafter referred to as the throttle opening T)
A) is detected.

An air flow meter 42 is provided in the intake passage 34 between the air cleaner 36 and the throttle valve 38. The air flow meter 42 outputs an electric signal corresponding to the mass of the air passing through the air cleaner 36 per unit time to the ECU 20. ECU 20
Detects the mass Ga of the air that has passed through the air cleaner 36 (hereinafter, referred to as the intake air amount Ga) based on the output signal of the air flow meter 42.

At the end of the introduction passage 32 on the side of the air chamber 30, a filter 43 for further purifying the air filtered by the air cleaner 36 is provided. In the middle of the introduction path 32, a canister close valve (hereinafter, referred to as CCV) 44
Are arranged. The CCV 44 is a two-position solenoid valve that is normally kept open and is closed when a drive signal is supplied from the ECU 20. In the above configuration, when the CCV 44 is open, the air chamber 30 communicates with the atmosphere via the air cleaner 36.

The air chamber 30 is provided with a tank internal pressure sensor 46. The tank internal pressure sensor 46 is
And outputs an electric signal corresponding to the internal pressure of the air chamber 30 to the ECU 20. The ECU 20 detects a pressure P _TANK in the air chamber 30 (hereinafter, referred to as a tank pressure P _TANK ) based on an output signal of the tank pressure sensor 46.

A filler pipe 48 for supplying fuel is connected to the fuel chamber 28. A fuel cap 50 is detachably attached to the upper end opening of the filler pipe 48. A lower communication path 52 is connected to the lower surface of the fuel chamber 28, and an upper communication path 54 is connected to the upper surface thereof. Lower communication passage 5
Both the second and upper communication passages 54 communicate with a volume-invariant sub-tank 56. The sub tank 56 has a built-in fuel injection pump (not shown). The fuel pumped up by the fuel injection pump is regulated to a predetermined pressure, and then is passed through a fuel supply passage (not shown) to the internal combustion engine 2.
4 is supplied to a fuel injection valve (not shown) that injects fuel.

The upper end of the sub-tank 56 is connected to a first vapor discharge passage 58 communicating with the filler pipe 48 described above. The first vapor discharge passage 58 is connected to the fuel tank 2.
This is a passage for discharging fuel vapor (vapor) generated in the second fuel chamber 28 and the sub tank 56. Fuel chamber 2
8 and a part of the fuel vapor generated in the sub-tank 56 is liquefied by touching the fuel adhering to the wall surface of the filler pipe 48, and then the fuel chamber 28 of the fuel tank 22 is liquefied.
Will be collected.

The filler pipe 48 is connected to a vapor introduction hole 62 of a canister 62 through a second vapor discharge passage 60.
a. The second vapor discharge passage 60 is a passage for discharging the remaining portion of the evaporated fuel generated in the fuel chamber 28 and the sub-tank 56 after liquefaction and the evaporated fuel generated in the filler pipe 48. These fuel vapors pass through the second vapor discharge passage 60 to the canister 62.
It is led to. The canister 62 is made of activated carbon that adsorbs evaporative fuel.
6, and has a role of preventing the evaporated fuel from being released into the atmosphere by adsorbing the evaporated fuel generated in the filler pipe 48.

The canister 62 has a fuel purge hole 62b on the same side as the vapor introduction hole 62a. A surge tank 66 of the internal combustion engine 24 communicates with a fuel purge hole 62 b of the canister 62 via a purge passage 64. The purge passage 64 is a passage for purging the fuel adsorbed by the canister 62 toward the intake passage 34. In the middle of the purge passage 64, an electromagnetically driven purge V
An SV 68 is provided. Purge VSV68 is EC
When the duty signal is supplied from U20, the opening is controlled to the opening according to the duty ratio. Purge VS
V68 is controlled such that the flow rate of the gas flowing through the purge passage 64 (hereinafter, referred to as a purge flow rate) becomes a predetermined value.

The canister 62 is provided with a vapor introduction hole 6.
An air introduction hole 62c is provided on the side opposite to the fuel purge hole 62a and the fuel purge hole 62b. Atmosphere introduction hole 62 of canister 62
c is the air chamber 3 of the fuel tank 22 through the gas passage 70.
It communicates with 0. Gas passage 70 and purge passage 64
Are connected to a bypass passage 72 that bypasses the canister 62. An electromagnetically driven bypass VSV is provided at a connection portion of the bypass passage 72 with the purge passage 64.
74 are provided. The bypass VSV 74 is a switching valve that switches between a communication state between the surge tank 66 and the canister 62 and a communication state between the surge tank 66 and the air chamber 30. The bypass VSV 74 is maintained so that the surge tank 66 communicates with the canister 62 in a normal state. When a drive signal is supplied from the ECU 20, the surge tank 66 bypasses the canister 62 and directly communicates with the air chamber 30. Is a two-position solenoid valve that operates as follows.

The exhaust passage 76 of the internal combustion engine 24_TwoC
A sensor 78 is provided. O_TwoThe sensor 78 is
The electric signal according to the concentration of the exhaust gas flowing inside the passage 76
The signal is output to the ECU 20. Oxygen concentration in exhaust gas
The degree is the air-fuel ratio of the air-fuel mixture supplied into the cylinder of the internal combustion engine 24.
Becomes thinner when the air-fuel ratio is richer than the ideal air-fuel ratio,
If the air-fuel ratio is leaner than the ideal air-fuel ratio
Thickens. O_TwoThe sensor 78 has a rich air-fuel ratio
In this case, a high signal of about 0.9 V is output and the air-fuel ratio is
Output a low signal of about 0.1V. E
CU20 is O _TwoEmpty based on the output signal of sensor 78
Whether the fuel ratio is rich or lean
Is determined.

The ECU 20 is connected with a crank angle sensor 80 and a water temperature sensor 82. The crank angle sensor 80 generates a reference signal each time the rotation angle of the crankshaft of the internal combustion engine 24 reaches a predetermined rotation angle, and generates a pulse signal each time the crankshaft rotates by a predetermined rotation angle. Further, the water temperature sensor 82 outputs an electric signal corresponding to the temperature of the cooling water for cooling the internal combustion engine 24. EC
U20 detects the engine speed NE and the rotation angle of the internal combustion engine 24 based on the output signal of the crank angle sensor 80, and detects the coolant temperature THW (hereinafter referred to as the coolant temperature THW) based on the output signal of the coolant temperature sensor 82. ) Is detected.

Next, the operation of the fuel storage device of the present embodiment will be described. In the system of the present embodiment, the evaporated fuel generated in the fuel chamber 28 and the sub-tank 56 of the fuel tank 22 flows through the upper communication passage 54 and the first vapor discharge passage 58, and flows through the filler pipe 48. Through the second vapor discharge passage 60 and is adsorbed by the activated carbon of the canister 62.

When the internal combustion engine 24 is in operation, a negative pressure is introduced to the surge tank 66. Under such circumstances CCV4
4 and the purge VSV 68 are opened, the air cleaner 36, the introduction passage 32, the air chamber 30, the gas passage 70, the atmosphere introduction hole 62c of the canister 62, the fuel purge hole 62b,
Air flows along the flow path of the purge passage 64 and the surge tank 66. In this case, the fuel adsorbed by the canister 62 is released from the activated carbon, and is purged to the purge passage 64 together with the air. Hereinafter, a mixture of fuel and air flowing from the canister 62 through the purge passage 64 to the intake passage 34 is referred to as a purge gas.

The purge gas purged into the purge passage 64 flows into the surge tank 66 and then flows into the air cleaner 36.
Is sucked into the cylinder of the internal combustion engine 24 together with the air that has flowed into the surge tank 66 through the throttle valve 38. Therefore, according to the system of the present embodiment, the fuel vapor generated in the fuel tank 22 can be supplied to the internal combustion engine 24 as fuel without being released to the atmosphere.

[0031] In order to ensure good exhaust emission in the internal combustion engine 24, it is necessary to maintain the actual air-fuel ratio A / F to stoichiometric air-fuel ratio A / F ₀ value near. When the purge gas is not purged from the canister 62 toward the intake passage 34, the fuel injection time TAU is set so that the ratio of the amount of intake air to the amount of fuel injected from the fuel injection valve becomes the stoichiometric air-fuel ratio A / F _0. By setting, it is possible to ensure good exhaust emissions. However,
In order to ensure good exhaust emissions under the condition that the purge gas is being purged toward the intake passage 34, the fuel injection time TAU set by using the above-described method is reduced by the time corresponding to the amount of fuel contained in the purge gas. Must be shorter.

In this embodiment, the fuel injection time TAU
Are feedback controlled so that the actual air-fuel ratio A / F becomes the ideal air-fuel ratio A / F ₀ . That is, the fuel injection time TAU is calculated based on the following equation. TAU = TP ｛{1+ (FAF-1.0) + (KG-1.0) + FPG} (1) where TP is a basic fuel injection time determined by the engine speed NE and the intake air amount Ga. And the FAF is the actual air-fuel ratio A /
F is a feedback correction coefficient for reducing the deviation between the stoichiometric air-fuel ratio A / F ₀ and a value that fluctuates around “1.0”. Is a value that fluctuates around “1.0”, and the FPG determines the air-fuel ratio deviation that has changed due to the purge of fuel from the canister 62. This is a purge correction coefficient for compensating and is a value that fluctuates around “0”.

The purge correction coefficient FPG is calculated based on the intake air amount Ga.
Volume ratio of purge flow rate (hereinafter, purge rate PGR)
) To compensate for the air-fuel ratio deviation caused by the purge.
It is obtained by multiplying by a vapor concentration correction coefficient FGPG representing a vapor concentration per 1% of a purge rate. Also,
The vapor concentration correction coefficient FGPG is obtained by dividing the average value FAFAV of the feedback correction coefficient FAF for each predetermined skip by "1.
0 ”from the change ΔFAFAV (= FAFAV−1.
0) is obtained by accumulating 0, and is a value that becomes smaller as the amount of vapor contained in the purge gas is larger, that is, a value that becomes larger as the vapor concentration becomes larger (a value that becomes larger on the negative side).
In the present embodiment, the vapor concentration is estimated from the value of the vapor concentration correction coefficient FGPG.

FIG. 2 is a diagram for explaining a method of calculating the vapor density correction coefficient FGPG. FIG. 2A shows O ₂
FIG. 2B shows the change with time of the output signal of the sensor 78, and FIG. 2B shows the change with time of the feedback correction coefficient FAF due to the change with time of the output signal of the O ₂ sensor 78 shown in FIG.
FIG. 2C shows a feedback correction section FA shown in FIG.
FIG. 2D shows the change over time of the vapor concentration correction coefficient FGPG according to the change over time in the average value FAFAV shown in FIG. 2C.
Each is shown.

As shown in FIG. 2, when the purge to the intake passage 34 is started, the feedback correction coefficient FAF decreases as the air-fuel ratio becomes richer, and the average value FAFAV also has a time delay. Decrease. Then, the vapor concentration correction coefficient FGPG decreases with a time delay as ΔFAFAV decreases. On the other hand, when the purge to the intake passage 34 is stopped, the feedback correction coefficient FAF increases as the air-fuel ratio becomes lean, and the average value FAFAV and the vapor concentration correction coefficient FGP
G increases with a time delay. When the change amount ΔFAFAV is smaller than a predetermined value, the vapor concentration correction coefficient FGPG is maintained at a previous value without accumulating the change amount ΔFAFAV.

In this embodiment, when the actual air-fuel ratio A / F becomes rich by purging the intake passage 34,
In order to make the actual air-fuel ratio A / F the stoichiometric air-fuel ratio A / F ₀ , the feedback correction coefficient FAF becomes smaller. In this case, the feedback correction coefficient FAF has a smaller value as the vapor density increases, and therefore, the vapor density is determined based on the decrease amount of the feedback correction coefficient FAF. When the feedback correction coefficient FAF is reduced due to the purge to the intake passage 34, the vapor concentration correction coefficient F
By reducing the GPG, the purge correction coefficient FPG is reduced, and the reduced feedback correction coefficient FAF is increased by the decrease of the purge correction coefficient FPG. According to this method, the fuel injection time TAU of the fuel injection valve can be shortened by a time corresponding to the amount of fuel contained in the purge gas to the intake passage 34.

As described above, the system according to the present embodiment supplies the fuel vapor generated in the fuel tank 22 to the internal combustion engine 24 as fuel without releasing it to the atmosphere. Accordingly, in the system of the present embodiment, the evaporated fuel flows from the fuel tank 22 and the passage connecting the fuel tank 22 and the surge tank 66 of the intake passage 34 (hereinafter, these are collectively referred to as an evaporative system) to the atmosphere. It is necessary to reliably detect leakage into the inside. Hereinafter, detection of leakage of the evaporated fuel into the atmosphere is referred to as “evaporation hole detection”.

FIG. 3 is a diagram for explaining the operation when the evaporative system hole is detected in this embodiment. FIG.
3 (A) shows the change with time in the tank internal pressure P _TANK of the air chamber 30 when the fuel vapor does not leak from the evaporative system to the atmosphere. FIG. 3 (B) shows the opening / closing operation of the CCV 44.
(C) shows the opening / closing operation of the purge VSV 68, respectively.

In the present embodiment, as shown in FIG. 3, after the operation of the internal combustion engine 24 is started, at time t ₁ C
Close the CV44. In this case, even if a negative pressure is introduced into the evaporative system by the operation of the internal combustion engine 24, fresh air flowing from the intake passage 34 to the air chamber 30 through the introduction passage 32 is not introduced. Tank pressure P _TANK increases to the negative pressure side. And the tank internal pressure P
_TANK is at a predetermined negative pressure (-2.6 kpa in FIG. 3A).
(At time t ₂ in FIG. 3), the purge VSV 68 is brought into the fully closed state. In this case, CCV44
And the purge VSV 68 are both closed.
The evaporative system is closed.

If there is no hole in the evaporation system,
After the system is closed, the tank pressure P _TANKIs in the evaporative system
Gradually increases toward the positive pressure side as the fuel
It will be good. On the other hand, if there is a hole in the evaporation system,
When air flows into the evaporative system through the hole,
P_TANKRapidly increases toward atmospheric pressure. Therefore, when
Time t_TwoTank pressure P_TANKDetect changes in
This makes it possible to detect an evaporative hole. So
Here, in the present embodiment, the evaporation hole detection is performed by the CCV44.
And after the purge VSV 68 is both closed.
Tank pressure P in air chamber 30_TANKThings to do based on changes in
And

Further, the system of this embodiment includes the fuel tank 22 separated from the fuel chamber 28 and the air chamber 30 by the bladder film 26 as described above. In such a fuel tank 22, if a hole is formed in the bladder film 26, the fuel leaks from the fuel chamber 28 to the air chamber 30, and a part of the fuel vapor may leak into the atmosphere. Therefore, in the system of the present embodiment, it is determined whether or not the bladder film 26 has a hole, that is, the fuel chamber 28
It is necessary to diagnose whether or not fuel is leaking. Hereinafter, the diagnosis of a hole in the bladder film 26 is referred to as bladder film hole detection.

FIG. 4 shows a bladder film 26 in this embodiment.
FIG. 7 shows a diagram representing the result of comparing the vapor density correction coefficient FGPG between a case where a hole is formed and a case where a hole is not formed. In FIG. 4, the solid line indicates a case where a hole is formed in the bladder film 26 in a state where the fuel vapor is not adsorbed in the canister 62, and the hole in the bladder film 26 in a state where the fuel vapor is saturated in the canister 62. Are indicated by broken lines, respectively.

If there is no hole in the bladder film 26,
Since fuel does not leak from the fuel chamber 28 to the air chamber 30, the vapor concentration in the air chamber 30 is maintained at an extremely low level. On the other hand, when the bladder film 26 has a hole, the fuel leaks from the fuel chamber 28 to the air chamber 30, so that the vapor concentration in the air chamber 30 is high. Therefore, by detecting the vapor concentration in the air chamber 30, it is possible to detect the film hole of the bladder film 26.

Therefore, in this embodiment, the bladder membrane hole detection is switched from the state of communication between the surge tank 66 and the canister 62 to the state of communication between the surge tank 66 and the air chamber 30 by the bypass VSV 74 (time t in FIG. 4).
₅ ) It is determined based on the subsequent vapor density correction coefficient FGPG. The vapor density correction coefficient FGPG is "0"
When the value becomes near, it can be determined that a large amount of fuel vapor does not exist in the air chamber 30, and it is determined that the bladder film 26 has no film hole. On the other hand, the vapor density correction coefficient F
When the GPG becomes large on the negative side, it can be determined that a large amount of fuel vapor is present in the air chamber 30, and it is determined that the bladder film 26 has a hole.

In the bladder membrane hole detection, as described above, the surge tank 66 is operated by the bypass VSV 74.
And the air chamber 30 need to be communicated directly. As described above, when the bladder film hole detection is performed, the canister 62 and the surge tank 66 do not communicate with each other, so that the fuel adsorbed by the canister 62 cannot be purged toward the intake passage 34. Therefore, when the bladder film hole detection is performed, the period during which the fuel adsorbed on the canister 62 can be purged (hereinafter, referred to as a purgeable period) is shortened.

Further, in detecting the evaporative system hole, as described above, it is necessary to introduce a negative pressure to the evaporative system with the CCV 44 closed. When a negative pressure is introduced into the evaporative system with the CCV 44 closed, the intake passage 34
2 does not flow toward the air chamber 30, the fuel adsorbed by the canister 62 can be effectively used to make the intake passage 3.
4 cannot be purged. in this way,
Also when the evaporation system hole detection is performed, the purgeable period of the fuel adsorbed on the canister 62 is shortened.

Therefore, if the evaporation hole detection and the bladder film hole detection are to be performed separately and independently, the purging period of the fuel adsorbed on the canister 62 becomes extremely short. Therefore, in the system according to the present embodiment, the bladder membrane hole detection is performed at the time of introducing a negative pressure in the evaporative system hole detection, thereby preventing the purging possible period from being significantly shortened.

FIG. 5 is a time chart for explaining the operation of the system of this embodiment. In addition, FIG.
(E) includes bypass VSV74 and CCV4, respectively.
4, a time chart of the purge VSV 68, the tank internal pressure P _TANK , and the vapor concentration correction coefficient FGPG are shown. In this embodiment, in order to detect the evaporative hole, C
When the CV 44 is closed (time t _{10 in} FIG. 5), the intake passage 34 is connected to the bypass VSV 74.
The drive signal is supplied such that the surge tank 20 provided in the air conditioner bypasses the canister 62 and directly communicates with the air chamber 30. When such a process is performed, thereafter, FIG.
As shown in FIG. 5D, the tank internal pressure P _TANK increases toward the negative pressure side due to no fresh air flowing into the air chamber 30, and as shown in FIG. 5E, the vapor concentration correction coefficient FGPG becomes
When the gas in the air chamber 30 is purged into the intake passage 34, the gas normally has a value near “0”. Therefore, according to the above-described processing, it is possible to detect the bladder film hole based on the vapor concentration correction coefficient FGPG in the process of introducing a negative pressure into the evaporation system in order to detect the evaporation hole.

[0049] Then, the tank internal pressure P at time t _{11
When TANK} reaches a predetermined negative pressure, the purge VSV 68 is fully closed, and the evaporator system is closed. Therefore, according to the above processing, after the evaporative system is closed, it is possible to detect the evaporative system hole based on the change in the tank internal pressure P _TANK . When evaporative system hole detection is completed, at time t _12, with CCV44 is opened, passed surge tank 66 and the canister 62 are communicated each other by stop supplying the drive signal to the bypass VSV74. In this case, since the CCV 44 is opened and the purge VSV 68 is maintained in the fully closed state, the pressure in the evaporation system is increased toward the atmospheric pressure. As described above, in this embodiment, the evaporative hole detection and the bladder film hole detection are performed simultaneously.

FIG. 6 is a flowchart showing an example of a control routine executed by the ECU 20 in the fuel storage device of the present embodiment to realize the above-described functions. The routine shown in FIG. 6 is a periodic interrupt routine that is repeatedly started at predetermined time intervals. When the routine shown in FIG. 6 is started, first, the process of step 200 is executed. In step 200, it is determined whether or not the execution condition of the evaporation hole detection is satisfied. Such an execution condition is the canister 6
During the operation of the internal combustion engine 24, the purge VSV 68 is opened to purge the fuel adsorbed in the second into the intake passage 34,
In addition, it is established when the water temperature THW at the time of starting the internal combustion engine 24 is low. As a result, if it is determined that the execution condition is not satisfied, the current routine is terminated without performing any processing. On the other hand, when the above execution condition is satisfied, the process of step 202 is executed next.

In step 202, the above step 200
Process of storing the vapor concentration correction coefficient FGPG as FGPG ₁ at the time the execution condition is satisfied in the evaporative system hole detection is performed in. At this time, the vapor concentration correction coefficient FGPG has a value corresponding to the vapor concentration of the purge gas purged from the canister 62. In particular,
When the vapor concentration is high, the value is large on the negative side,
On the other hand, the value becomes closer to "0" as the vapor concentration becomes thinner.

In step 204, the bypass VSV 74
A process of supplying a drive signal to the is performed. After the process of step 204 is performed, the surge tank 66 is directly connected to the air chamber 30 by bypassing the canister 62 thereafter. In step 206, a process of supplying a drive signal to the CCV 44 is performed. This step 20
After the processing of No. 6, the introduction path 32 between the intake passage 34 and the air chamber 30 is shut off thereafter. In this case, since fresh air flowing from the intake passage 34 to the air chamber 30 through the introduction path 32 does not flow, the tank internal pressure P _TANK of the air chamber 30 increases to the negative pressure side.

By the way, the tank internal pressure P _{TANK of the} air chamber 30
Is increased to the negative pressure side in a short time, that is, when the introduction speed of the negative pressure to the evaporative system (hereinafter, referred to as the negative pressure introduction speed) is high, the CCV 44 is closed and the bypass VSV 74 is connected to the intake passage. Since the period until the purge VSV 68 is closed after the direct communication between the air chamber 30 and the air chamber 30 is shortened, a period for purging gas from the air chamber 30 to the intake passage 34 (hereinafter, referred to as a purge period). Becomes shorter. When the purge period is short as described above, the vapor concentration correction coefficient FGPG may not change due to the calculation principle even if the purge gas is a gas having a high vapor concentration. In this case, the vapor concentration in the air chamber 30 cannot be accurately grasped, and it becomes impossible to accurately detect whether or not the bladder film 26 has a hole.

Therefore, in order to accurately detect whether or not a hole is formed in the bladder film 26, at least the gas concentration correction coefficient FGPG after the gas purge is changed during the purge period from the air chamber 30 to the intake passage 34. Then it needs to be longer than expected. That is, it is necessary to reduce the negative pressure introduction speed to the evaporator system so that the tank internal pressure P _TANK of the air chamber 30 gradually increases toward the negative pressure side. Therefore,
In this routine, when the process of step 206 is completed, the process of step 208 is executed next.

In step 208, the engine speed N is adjusted so that the purge flow rate flowing through the purge passage 64 becomes a predetermined value.
Processing for calculating a duty ratio when driving the purge VSV 68 based on E, the intake air amount Ga, the throttle opening TA, and the tank internal pressure P _TANK is executed. In the present embodiment, the duty ratio to the purge VSV 68 is calculated by referring to a predetermined map regarding the above parameters.

In step 210, step 208 is performed.
VSV 68 according to the duty ratio calculated in
Is performed. This step 2
When the processing in step 10 is executed, the purge VSV
The valve is opened to an opening corresponding to the pressure ratio and flows through the purge passage 64.
The purge flow rate becomes a predetermined value. In step 212, empty
Whether the introduction of the negative pressure into the air chamber 30 has been completed, specifically,
Tank pressure P in air chamber 30_TANKIs a predetermined negative pressure P₀Reach
It is determined whether or not it has been performed. As a result, the tank pressure P_TANK
Is the predetermined negative pressure P₀If it is determined that has not been reached,
The process of step 208 is repeatedly executed. one
, Tank pressure P _TANKIs the predetermined negative pressure P₀Determined to have reached
If so, the processing of step 214 is executed next.
You.

In step 214, a process for closing the purge VSV 68 is executed. When the process of step 214 is performed, the purge passage 64 is shut off, and the evaporation system is closed. In step 216,
A process of reading the vapor density correction coefficient FGPG as FGPG ₂ is executed. At this time, the vapor density correction coefficient FG
PG usually has a value corresponding to the vapor concentration of the gas purged directly from the air chamber 30 to the intake passage 34.

In step 218, step 216 is performed.
And the difference ΔFGPG (= FGPG ₂ −F) between FGPG ₂ read at step 202 and FGPG ₁ stored at step 202.
GPG ₁ ) is calculated. By the way, a fixation abnormality may occur in the bypass VSV 74. If an abnormality occurs in the bypass VSV 74, even if the surge tank 66 and the air chamber 30 are directly communicated with each other in order to detect the bladder membrane hole, the surge tank 66 and the canister 6 are not connected.
2 is maintained. In this case, the vapor concentration correction coefficient FGPG is a value corresponding to the vapor concentration of the gas purged from the canister 62, not the vapor concentration of the gas in the air chamber 30. Therefore, the bypass VS
If the presence or absence of the V74 fixation abnormality cannot be determined, the presence or absence of a film hole in the bladder film 26 cannot be accurately detected based on the vapor concentration correction coefficient FGPG. Therefore, in order to prevent erroneous detection of the film hole of the bladder film 26,
It is necessary to determine whether or not the bypass VSV 74 is stuck. Therefore, in the present routine, when the process of step 218 is completed, the process of step 220 is executed next.

In step 220, it is determined whether the absolute value of ΔFGPG is smaller than the predetermined value α ₁ and whether FGPG ₁ is smaller than the predetermined value CF _GPGF . Note that the predetermined value α ₁ is a very small value that can determine that the vapor density correction coefficient FGPG has hardly changed before and after the drive signal for switching the communication state to the bypass VSV 74 is supplied. Further, the predetermined value CF _GPGF is
The air chamber 30 in a situation where the bladder film 26 has no holes
Is the minimum value of the vapor concentration correction coefficient FGPG for determining that the vapor concentration is as low as about the vapor concentration of, and is set to a value obtained by an experiment in advance.

In step 220, | ΔFGP
When both G | <α ₁ and FGPG ₁ <CF _GPGF are satisfied, it can be determined that the vapor concentration is maintained to be constant to some extent before and after the supply of the drive signal to the bypass VSV 74. In this case, the bypass VSV 74
Communication state is not switched due to the bypass VSV 74
It can be determined that a fixation abnormality has occurred in the. Therefore, | ΔF
If it is determined that both GPG | <α ₁ and FGPG ₁ <CF _GPGF are satisfied, the process of step 222 is next executed.

On the other hand, if | ΔFGPG | <α ₁ does not hold, it can be determined that the vapor concentration has changed significantly before and after the supply of the drive signal to the bypass VSV 74, and that the bypass VSV 74 is functioning normally. it can. Also,
If FGPG ₁ <CF _GPGF does not hold, the bypass V
It can be determined that the vapor concentration from the canister 62 before the supply of the drive signal to the SV 74 is low. If a drive signal is supplied to the bypass VSV 74 in such a state, the vapor concentration in the air chamber 30 is normally in a low state, so that a situation where ΔFGPG does not change may occur. For this reason, _{if it} is determined that the bypass VSV 74 is stuck based on ΔFGPG in a situation where FGPG ₁ <CF _GPGF is not established, the bypass VSV 74 may be stuck abnormally, even though the bypass VSV 74 functions normally. May be erroneously determined. Therefore, F
If GPG ₁ <CF _GPGF does not hold, then | Δ
If it is determined that either FGPG | <α ₁ or FGPG ₁ <CF _GPGF is not established, then step 2
24 are executed.

At step 222, the bypass VSV 74
Process of setting the bypass VSV abnormality flag FLAG ₁ indicating that the fixation abnormality has occurred is executed. When the bypass VSV abnormality flag FLAG ₁ is set, to notify the abnormality of the bypass VSV74, with warning to the vehicle occupant is issued, a warning lamp is turned on.
In the case where the bypass VSV abnormality flag FLAG ₁ is 2 times set, it may be caused to activate an alarm or warning lamp.

[0063] At step 224, the process of resetting the bypass VSV abnormality flag FLAG ₁ is executed. When the processing of step 222 or 224 is completed, the processing of step 226 is executed next. Step 226
In the example, there is no hole in the bladder film 26 and the bladder film 26
Is functioning normally.

FIG. 7 is a diagram showing a map representing the relationship between ΔFGPG and FGPG ₁ for determining whether or not a hole is formed in the bladder film 26 in this embodiment. F
GPG ₁ has a large value on the negative side when a large amount of fuel is adsorbed in the canister 62, while the canister 6 has a large value.
The value becomes closer to “0” as the amount of fuel adsorbed in 2 decreases. FGPG ₂ has a large value on the negative side when the bladder film 26 has a hole, and has a value near “0” when the bladder film 26 has no hole.

In step 226, the presence or absence of a hole in the bladder film 26 is determined by referring to the map shown in FIG. As a result, if it is determined that the bladder film 26 has a hole, the process of step 228 is executed next. On the other hand, if it is determined that no hole is formed in the bladder film 26, the process of step 230 is executed next.

[0066] At step 228, the process of setting the leakage flag FLAG ₂ indicating that a hole in the bladder membrane 26 is executed. When the liquid leakage flag FLAG ₂ is set, to notify the abnormality of the bladder membrane 26, the alarm is issued to a vehicle occupant, a warning lamp is turned on. In the case where leakage flag FLAG ₂ is twice set, it is also possible to operate an alarm or a warning lamp.

In step 230, the liquid leakage flag FLA
Process of resetting the G ₂ is performed. Step 2 above
When the processing of step 28 or 230 is completed,
At 32, a process for detecting an evaporative hole is executed. Specifically, the purge VSV 68 causes the purge passage 6
4 is shut off, and thereafter, a hole in the evaporation system is detected based on a change in the tank internal pressure P _TANK . When the process of step 232 ends, the current routine ends.

According to the above processing, bladder film hole detection can be performed in the process of introducing a negative pressure into the evaporation system in order to detect the evaporation system hole. In this case, the time when the negative pressure is introduced into the evaporative system and the time when the presence or absence of the film holes in the bladder film 26 are overlapped, so that the period for purging the fuel adsorbed by the canister 62 into the intake passage 34 is remarkable. Shortening is avoided. Therefore, according to the fuel storage device of the present embodiment, it is possible to properly perform both the evaporative hole detection and the bladder film hole detection, and sufficiently secure a purgeable period in which the fuel adsorbed in the canister 62 can be purged. Is possible.

According to the above-described process, in the process in which the negative pressure is introduced into the evaporative system after the CCV 44 is closed, the purge VSV 68 adjusts the purge flow rate flowing through the purge passage 64 to a predetermined value. Duty control is performed. For this reason, according to the present embodiment, it is possible to prevent the negative pressure introduction speed when introducing the negative pressure into the evaporative system from becoming excessively large, and to bypass the canister 62 from the air chamber 30 and bypass the intake passage 34. It is possible to lengthen the purge period of the gas to be purged. Therefore, according to the fuel storage device of the present embodiment, after the purge, a period sufficient for the vapor concentration correction coefficient FGPG to change due to the purge is ensured, and the detection accuracy of the bladder film hole detection is improved. Improvement can be achieved.

Further, according to the above-described processing, it is possible to determine whether or not the bypass VSV 74 is abnormally fixed before the bladder film hole is detected. Therefore, according to the present embodiment,
Bladder film 26 caused by fixation of bypass VSV 74
Erroneous determination of the membrane hole can be avoided. In the present embodiment, when determining the fixation abnormality of the bypass VSV 74, the vapor density in the case where the drive signal is not supplied to the bypass VSV 74 is compared with the vapor concentration in the case where the drive signal is supplied. When the drive signal is supplied to the bypass VSV 74 when the bypass VSV 74 functions normally, the surge tank 66 bypasses the canister 62 and directly communicates with the air chamber 30. Thus, the bypass V
When judging the fixation abnormality of the SV 74, the canister 62
And the surge tank 66 may not communicate with each other, and the fuel adsorbed by the canister 62 may not be purged toward the intake passage 34 in some cases. Therefore,
If it is determined that the bypass VSV 74 is stuck, there is a possibility that the purgeable period of the fuel adsorbed on the canister 62 may be shortened.

Therefore, in this embodiment, the bypass V
The determination of the SV74 fixation abnormality is performed in the process of introducing a negative pressure into the evaporation system in order to detect the evaporation system hole. In this case, when the negative pressure is introduced into the evaporative system and the bypass VS
By overlapping the time when the V74 sticking abnormality is determined, it is possible to prevent the period in which the fuel adsorbed in the canister 62 is purged into the intake passage 34 from being significantly shortened. Therefore, according to the fuel storage device of the present embodiment, it is possible to adequately perform both the detection of the evaporative system hole and the determination of the fixation abnormality of the bypass VSV 74 and to secure a sufficient purging period in which the fuel adsorbed on the canister 62 can be purged. It is possible to do.

In the above embodiment, the bladder film 2
6 corresponds to the “separation membrane” described in the claims, and the purge passage 64 corresponds to the “communication passage” described in the claims.
The control for switching the bypass VSV 74 to detect the bladder membrane hole is described in “communication path switching control” described in the claims, the purge VSV 68 is described in the “purge control valve” described in the claims, and the bypass VSV 74 is described in the claims. Each corresponds to a “switching valve” described in the claims.

In the above embodiment, the ECU 2
0 indicates that the “hole detection means” described in the claims by performing the evaporative system hole detection, and “the fuel leakage detection means” described in the claims by performing the bladder membrane hole detection. By detecting the tank internal pressure P _TANK of the air chamber 30 based on the output signal of the tank internal pressure sensor 46, the "air chamber pressure detecting means" recited in the claims
By executing the processing of step 210, the "opening degree control means" described in the claims is realized.

Next, a fuel storage device according to a second embodiment of the present invention will be described with reference to FIGS. 8 to 10 together with FIG. The fuel storage device of the present embodiment has a configuration similar to the configuration shown in FIG. 1 described above, and is mounted on a hybrid vehicle that travels by appropriately combining an internal combustion engine 24 and an electric motor as power sources, as described later. You. The system of the present embodiment includes the fuel storage device shown in FIG.
This is realized by causing the ECU 20 to execute a routine shown in FIG. 9 instead of the routine shown in FIG.

FIG. 8 is a diagram schematically showing a drive mechanism of a vehicle equipped with the fuel storage device of this embodiment. As shown in FIG. 8, an axle 10 connecting the left wheel FL and the right wheel FR.
At 0, the speed reducer 102 is fixed. Reducer 102
, A planetary gear mechanism 106 is engaged via a gear 104. The planetary gear mechanism 106 includes the internal combustion engine 24 described above.
Planetary carrier, electric motor 1 connected to the output shaft of
A ring gear connected to the output shaft of No. 10 and a sun gear connected to the output shaft of the generator 112 are provided.

Generator 112 and electric motor 11
0 is electrically connected to a battery 118 via an inverter 114 and a main relay 116. The main relay 116 has a function of turning on or off a power supply circuit from the battery 118 to the inverter 114 by being driven by the ECU 20. The inverter 114 is
Between the battery 118 and the generator 112, and
Between the battery 118 and the electric motor 110, each has a function of converting a DC current and a three-phase AC current by a three-phase bridge circuit formed by a plurality of power transistors. The generator 112 and the electric motor 110 are controlled at a rotation speed corresponding to the frequency of the alternating current by appropriately driving the power transistor in the inverter 114 by the ECU 20, and the generator 112 and the electric motor 110 correspond to the magnitude of the current. Generates torque.

The generator 112 has a function as a starter motor for starting the internal combustion engine 24 by supplying power from the battery 118 via the inverter 114 when the start of the internal combustion engine 24 is not completed. After the start of the engine 24 is completed, the internal combustion engine 2
4 through the inverter 114 by the output of the battery 11
8 or a function as a generator for supplying electric power to the electric motor 110. Also, the electric motor 110
Has a function as an electric motor that generates torque for assisting the output of the internal combustion engine 24 by being appropriately supplied with electric power during normal traveling, and a battery 118 via the inverter 114 by the rotation of the axle 100 during braking. Has a function as a generator for supplying power to the power supply.

In this embodiment, the vehicle is an internal combustion engine 24
And a hybrid vehicle that travels by appropriately combining the motor and the electric motor 110. The ECU 20 calculates a required driving force based on the accelerator operation amount and the vehicle speed, and specifically, when the vehicle starts or runs at a low speed so that the internal combustion engine 24 can operate efficiently with respect to the required driving force. When the engine efficiency is low, the axle 1 between the internal combustion engine 24 and the electric motor 110 is stopped so that the internal combustion engine 24 is stopped.
Control the torque ratio to 00.

In this embodiment, when the bladder membrane hole is detected, the purge from the canister 62 is interrupted by the bypass VSV 74, and the surge tank 66 and the air chamber 30 are directly connected. Also, when performing the evaporative system hole detection, in order to keep the evaporative system closed,
The purge from the canister 62 is interrupted. For this reason,
In this embodiment, the purging period of the fuel adsorbed on the canister 62 is shortened due to the bladder film hole detection and the evaporative hole detection.

In this embodiment, since the vehicle is a hybrid vehicle as described above, the vehicle may run with only the electric motor 110 as a power source, that is, with the internal combustion engine 24 stopped. When the internal combustion engine 24 is stopped, no negative pressure is introduced into the evaporative system, and the intake passage 3
4, it becomes impossible to purge the purge gas. On the other hand, when the internal combustion engine 24 is operating, a purge from the canister 62 can be performed by introducing a negative pressure into the evaporation system.

Accordingly, when the bladder membrane hole detection and the evaporative system hole detection are performed, after the condition for operating only the electric motor 110, that is, the condition for stopping the internal combustion engine 24 is satisfied, the detection is performed. If the internal combustion engine 24 is maintained in the operating state for an extended period, the period during which the fuel adsorbed by the canister 62 can be purged can be increased.

Therefore, the system according to the present embodiment provides the internal combustion engine 2 after the period in which the bladder membrane hole detection and the evaporative system hole detection are performed after the stop condition of the internal combustion engine 24 is satisfied.
4 is to be stopped. FIG. 9 shows a flowchart of an example of a control routine executed by the ECU 20 in the fuel storage device of the present embodiment. The routine shown in FIG. 9 is a periodic interrupt routine that is repeatedly started every predetermined time. In FIG. 9, steps that execute the same processing as the steps shown in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

That is, in the routine shown in FIG. 9, after the execution condition of the evaporation system hole detection is satisfied in step 200, the process of step 250 is executed. In step 250, the processing of reading the time t ₂₀ at the time the execution condition is satisfied in the evaporative system hole detected in the step 200 is executed. When the process of step 252 is completed, the processes of step 202 and thereafter are executed.
Then, after the process for detecting the evaporative holes is performed in step 232, the process of step 252 is performed next.

In step 252, the above-mentioned step 202
It is determined whether or not the FGPG ₁ stored in is smaller than the predetermined value A. Note that the predetermined value A is a minimum value of the vapor concentration correction coefficient FGPG at which it is determined that the amount of fuel adsorbed in the canister 62 is not so large. FGPG ₁ <A
Is satisfied, it can be determined that a large amount of fuel has been adsorbed in the canister 62, and it can be determined that it is necessary to secure a sufficient purge period from the canister 62. Therefore,
If such a determination is made, the process of step 254 is performed next.

On the other hand, if FGPG ₁ <A is not satisfied, it can be determined that it is not necessary to lengthen the purge period from the canister 62. Therefore, when such a determination is made, the process of step 256 is executed next. In step 254, after the stop condition of the internal combustion engine 24 is satisfied, the period to the actual internal combustion engine 24 is stopped (hereinafter, extension period referred to) D _T, from the time t ₂₀ read in step 250 time until the current time _{t 21 (t 21 -t 20)} ,
That is, a process for setting the time when the purge from the canister 62 is interrupted to perform the bladder film hole detection and the evaporation system hole detection is performed.

At step 256, a process for setting the extension period _DT to "0" is executed. When the processing in step 254 or 256 ends, the current routine ends. According to the above-described processing, the extension period _DT until the internal combustion engine 24 is actually stopped after the stop condition of the internal combustion engine 24 is satisfied can be determined. FIG. 10 shows a flowchart of an example of a control routine executed by the ECU 20 in a vehicle equipped with the fuel storage device of the present embodiment. The routine shown in FIG. 10 is a periodic interruption routine that is repeatedly started at predetermined time intervals. When the routine shown in FIG. 10 is started, first, the process of step 260 is executed.

At step 260, it is determined whether or not a condition for stopping the internal combustion engine 24 is satisfied. The condition for stopping the internal combustion engine 24 is satisfied when the vehicle runs using only the electric motor 110 as a power source, specifically, when the efficiency of the internal combustion engine 24 decreases such as when the vehicle starts or runs at low speed. .
As a result, if the above condition is not satisfied, then, in step 262, a process of continuing the operation state of the internal combustion engine 24 is executed. Then, when the process of step 262 ends, the current routine ends.

On the other hand, if it is determined in step 260 that the condition for stopping the internal combustion engine 24 is satisfied, then the process of step 264 is executed. In step 264, it is determined whether or not the vehicle is decelerating, specifically, whether or not electric power is being recovered from the electric motor 110 to the battery 118 due to the vehicle deceleration. As a result, when the above condition is satisfied, by stopping the internal combustion engine 24,
It is possible to increase the energy recovered to the battery 118. Therefore, if it is determined that the above condition is satisfied, the process of step 266 is executed next.

In step 266, a process for stopping the internal combustion engine 24, specifically, a process for stopping the fuel supply to the internal combustion engine 24 and closing the throttle valve 38 is executed. When the process of step 266 is executed, the internal combustion engine 24 is stopped. This step 2
When the process at 66 ends, the current routine ends.

On the other hand, if it is determined in step 264 that the vehicle is not decelerating, then in step 268
Is performed. In step 268, the extended time D obtained by executing the routine shown in FIG.
A process of subtracting _T by a predetermined time τ is executed. still,
The predetermined time τ is set to the activation period of this routine.

In step 270, the above-mentioned step 268
It is determined whether or not the extended time _DT subtracted from is less than "0". If D _T ≦ 0 is not established, it can be determined that it is not yet time to stop the internal combustion engine 24. Accordingly, if it is determined that D _T ≦ 0 is not established, then, in step 262, processing for continuing the operation state of the internal combustion engine 24 is executed.

On the other hand, if D _T ≦ 0 holds, it can be determined that the time has come to stop the internal combustion engine 24. Therefore, when it is determined that D _T ≦ 0 is satisfied, the process of stopping the internal combustion engine 24 is executed in step 266 described above. According to the above process, even if the stop condition of the internal combustion engine 24 is satisfied, if the vehicle is not decelerating, the operating state of the internal combustion engine 24 can be continued for the extended period _DT . That is, when the amount of fuel adsorbed on the canister 62 is small, the internal combustion engine 24 is stopped immediately after the stop condition is satisfied, while when the amount of fuel adsorbed on the canister 62 is large, the internal combustion engine 24 is stopped after the stop condition is satisfied. After a lapse of a period in which the purge from the canister 62 is interrupted, the internal combustion engine 24 is stopped.

As described above, in this embodiment, even when the stop condition of the internal combustion engine 24 is satisfied, the operating state of the internal combustion engine 24 may be continued. In such a case, a negative pressure can be introduced into the evaporative system by the operation of the internal combustion engine 24, so that the internal combustion engine 24 is adsorbed on the canister 62 for a longer period of time than when stopped immediately after the stop condition is satisfied. The fuel can be purged toward the intake passage 34. Therefore, according to the present embodiment, even when the purgeable period from the canister 62 is eroded due to the bladder membrane hole detection and the evaporative system hole detection, the canister 6 can be used.
A period for purging the fuel adsorbed in the fuel cell 2 can be sufficiently ensured.

In the above embodiment, the ECU 20
After the stop condition of the internal combustion engine 24 is satisfied,
By stopping the internal combustion engine 24 after _T has elapsed, the "engine control means" described in the claims is realized. Next, referring to FIG. 11 together with FIG.
A description will be given of a fuel storage device according to a third embodiment of the present invention.

In this embodiment, the fuel chamber 28 and the air chamber 3
Since the bladder film 26 separating from zero expands and contracts according to the amount of fuel stored in the fuel chamber 28, the volume of the air chamber 30 can fluctuate. When the volume of the air chamber 30 changes, the tank internal pressure P _TANK changes. For this reason, in the above configuration, even if the purge VSV 68 is opened to the same opening, the negative pressure introduction speed may be greatly different. In this case, the purge period from the air chamber 30 to the intake passage 34 fluctuates, which makes it impossible to accurately detect whether or not the bladder film 26 has a hole as in the first embodiment. Alternatively, the air chamber 30 may be used to detect bladder membrane holes.
, The time for introducing a negative pressure (hereinafter, referred to as a negative pressure introducing time) becomes extremely long. Therefore, it is not appropriate to change the negative pressure introduction speed in order to avoid such inconvenience.

Therefore, in this embodiment, the air chamber 30
The opening degree of the purge VSV 68 is duty-controlled based on the tank internal pressure P _TANK so that the speed of introducing the negative pressure to the evaporation system is maintained within an appropriate range even when the volume of the fuel cell fluctuates. In the system according to the present embodiment, in the fuel storage device shown in FIG. 1, the ECU 20 performs steps 208 and 210 in the routine shown in FIG.
This is realized by changing and executing the processing of steps 300 to 310 in the routine shown in FIG.

That is, in the routine shown in FIG. 11, after the CCV 44 is closed in step 206 so that the introduction path 32 between the intake passage 34 and the air chamber 30 is shut off, the processing in step 300 is executed. . Step 30
At 0, the change per unit time of the tank internal pressure P _TANK per unit time (P _TANK (t) -P
It is determined whether or not _TANK (t + Δt) / Δt exceeds a predetermined value B. Hereinafter, the amount of change in the tank internal pressure P _TANK per unit time is referred to as a negative pressure introduction speed ΔP _TANK / Δt. The negative pressure introduction speed ΔP _TANK / Δt is equal to the tank internal pressure P _TANK
The larger the amount of change to the negative pressure side, the larger the value. The predetermined value B is a negative pressure introduction speed ΔP _TANK / Δt at which it can be determined that the tank internal pressure P _TANK is changing to the negative pressure side at an appropriate speed.
Is the maximum value of When ΔP _TANK / Δt> B holds, it can be determined that the tank internal pressure P _TANK rapidly increases to the negative pressure side. In this case, the purge period from the air chamber 30 to the intake passage 34 is shortened, so that the vapor concentration in the air chamber 30 cannot be accurately grasped.
It is impossible to accurately detect whether or not there is a hole. Therefore, ΔP _TANK /
If it is determined that Δt> B holds, the process of step 302 is executed next to reduce the negative pressure introduction speed.

In step 302, a process for reducing the duty ratio for the purge VSV 68 is performed. When the process of step 302 is executed, the opening degree of the purge VSV 68 shifts to the valve closing side, so that the effective area of the flow path of the purge passage 64 decreases, and the negative pressure introduction speed decreases.
On the other hand, in the above step 300, ΔP _TANK / Δt> B
_Does not hold, it can be determined that the tank internal pressure P _TANK has not rapidly increased to the negative pressure side, and it is not necessary to reduce the negative pressure introduction speed. Therefore, if it is determined in step 300 that ΔP _TANK / Δt> B does not hold, the process of step 304 is executed next.

In step 304, the negative pressure introduction speed ΔP
It is determined whether or not _TANK / Δt is smaller than a predetermined value C. The predetermined value C is a negative pressure introduction speed Δ at which it can be determined that the tank pressure P _TANK is changing to the negative pressure side at an appropriate speed.
This is the minimum value of P _TANK / Δt. If ΔP _TANK / Δt <C is not satisfied, it can be determined that the tank internal pressure P _TANK has increased to the negative pressure side within an appropriate range. In this case, it can be determined that the purge VSV 68 has been opened to an appropriate opening. Therefore, if it is determined that ΔP _TANK / Δt <C is not satisfied, the process of step 306 is performed next.

In step 306, the purge VSV 68
Process to maintain the duty ratio of
Is performed. On the other hand, in step 304, ΔP_TANK
/ Δt <C, the tank internal pressure P_TANKIs negative pressure
It can be determined that the side has not changed much. in this case,
The purge period from the air chamber 30 to the intake passage 34 becomes longer.
As a result, the detection time of bladder membrane hole detection becomes unduly long.
I will. Therefore, in step 304 above, ΔP _TANK
/ Δt <C, the negative pressure introduction speed
Next, in order to increase the degree, the processing of step 308 is executed.
It is.

In step 308, a process for increasing the duty ratio for the purge VSV 68 is executed. When the process of step 308 is performed, the opening degree of the purge VSV 68 shifts to the valve opening side, so that the effective area of the flow path of the purge passage 64 increases, and the negative pressure introduction speed increases.
When the processing of steps 302, 306, and 308 is completed, the processing of step 310 is performed next.

In step 310, a process for duty-driving the purge VSV 68 is executed. Present step 31
When the process of 0 is executed, the purge VSV 68 is opened to an opening corresponding to the duty ratio, and the negative pressure introduction speed ΔP _TANK /
Δt is maintained in a desired range. When the processing of step 310 is completed, the processing of step 212 and thereafter is executed.

According to the above-described process, after the CCV 44 is closed, during the process of introducing a negative pressure into the evaporation system, the purge VS
V68 is duty-controlled so that the introduction speed of the negative pressure introduced into the evaporation system is maintained within a predetermined range. Therefore, according to the present embodiment, regardless of the magnitude of the tank internal pressure P _TANK , the introduction speed of the negative pressure to the evaporative system is maintained within a predetermined range, thereby bypassing the canister 62 from the air chamber 30. The purge period of the gas purged to the intake passage 34 can be maintained in an appropriate range. That is, after the purge, the vapor concentration correction coefficient FG
It is possible to secure a sufficient period for the PG to change, and it is possible to prevent the negative pressure introduction time for detecting the bladder membrane hole from becoming unduly long. Therefore, according to the fuel storage device of the present embodiment, the detection accuracy of the bladder membrane hole detection is improved even under a situation where the volume of the air chamber 30 changes, that is, under a situation where the tank internal pressure P _TANK changes. The detection time can be prevented from becoming extremely long.

In the above embodiment, the ECU 20
Executes the processing of step 310, thereby realizing the "opening control means" described in the claims. Next, a fourth embodiment of the present invention will be described with reference to FIGS. In the system according to the present embodiment, in the fuel storage device shown in FIG. 1, the ECU 20 replaces the routine shown in FIG.
This is realized by executing the routine shown in FIG.

FIG. 12 shows a flowchart of an example of a control routine executed by the ECU 20 in the fuel storage device of the present embodiment. The routine shown in FIG. 12 is a periodic interruption routine that is repeatedly started at predetermined time intervals.
In FIG. 12, steps that execute the same processing as the steps shown in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

That is, in the routine shown in FIG. 12, after the processing of step 218 is executed, the processing of step 320 is executed next. At step 320, Δ
The absolute value of FGPG is smaller than the predetermined value α ₁ , and
FGPG ₁ whether the predetermined value CF _GPGF more is determined. As a result, | ΔFGPG | <α ₁ or FG
If it is determined that PG ₁ ≧ CF _GPGF is not established, the processing of step 220 and thereafter is executed.

On the other hand, | ΔFGPG | <α ₁ and F
If both GPG ₁ ≧ CF _GPGF are satisfied, it is determined that the vapor concentration has not changed before and after the supply of the drive signal to the bypass VSV 74 in a situation where the vapor concentration of the gas purged from the canister 62 into the intake passage 34 is low. it can. In this case, whether the vapor concentration has not changed due to the fixation abnormality of the bypass VSV 74 or the vapor concentration has been reduced due to the vapor concentration of the air chamber 30 being low under the condition that the bypass VSV 74 functions normally. It cannot be distinguished that it has not changed. Therefore, if it is determined that the above condition is satisfied, then step 322 is executed.
Is performed.

At Step 322, the bypass VSV 74
A process of suspending the detection of the fixation abnormality is performed. When the process of step 322 is completed, the process proceeds to step 22
Steps 6 and after are executed. According to the above processing, when the vapor concentration of the gas purged from the canister 62 to the intake passage 34 is low, the detection of the fixation abnormality of the bypass VSV 74 can be suspended.

FIG. 13 is a flowchart showing an example of a subroutine executed by the ECU 20 when the detection of the fixation abnormality of the bypass VSV 74 is suspended in the fuel storage device of the present embodiment. The routine shown in FIG.
This routine is started when the abnormality detection of the bypass VSV 74 is suspended in step 322 in the routine shown in FIG. When the routine shown in FIG. 13 is started,
First, the process of step 330 is performed.

In step 330, the bypass VSV 74
A process of supplying a drive signal to the is performed. When the process of step 330 is performed, the bypass VSV 74
Function normally, the surge tank 66 bypasses the canister 62 and communicates directly with the air chamber 30. On the other hand, when the fixation abnormality occurs in the bypass VSV 74, the surge tank 66 and the canister 62 are maintained in a communication state.

In Step 332, the above Step 330
Is performed for a predetermined time T ₀Whether or not
Is determined. The processing in step 332 is performed according to the above condition.
Is repeatedly executed until the condition is satisfied. The predetermined time T₀
Means that the amount of fuel adsorbed on the canister 62 is small.
Of the canister 6 due to evaporation of the fuel in the fuel tank 22 from the
2 is the time when the amount of fuel adsorbed is expected to be large
The value is set in advance to a value obtained by an experiment. Up
The predetermined time T₀Is passed, the canister 62
Fuel is adsorbed. In the present step 332, the predetermined
Time T₀If has elapsed, then the processing of step 334 is performed.
Is executed.

In step 334, the above-mentioned step 330
Is performed for a predetermined time T ₀At the time
The vapor concentration correction coefficient FGPG in_Tenage
Then, the process of storing is performed. This routine is executed as described above.
When the abnormality detection of the bypass VSV 74 is suspended,
Specifically, the vapor concentration of the gas from the canister 62 is
The drive signal to the bypass VSV 74 under thin conditions
Starts when the vapor concentration has not changed before and after the supply.
You. Therefore, at the time when this step 334 is executed,
The vapor concentration correction coefficient FGPG is
It is a value in the vicinity of “0” that is determined to be “0”.

At Step 336, the bypass VSV 74
Is stopped.
When the process of step 336 is performed, the bypass VS
Surge tank 6
6 and the canister 62 communicate with each other. In step 338, processing to read the vapor concentration correction coefficient FGPG as FGPG ₁₁ is executed. At this time, the vapor concentration correction coefficient FGPG has a value corresponding to the vapor concentration of the fuel adsorbed on the canister 62. Specifically, the vapor concentration correction coefficient FGPG has a small value according to the vapor concentration of the fuel adsorbed over the canister 62 for a long period of time when the sticking abnormality has not occurred in the bypass VSV 74, while the sticking abnormality in the bypass VSV 74. If FG occurs, the above FG
Approximate to the PG ₁₀ "0" to a value in the vicinity.

In step 340, the above-mentioned step 338 is performed.
And the difference ΔFGPG ₁₂ between the FGPG ₁₁ read at step 334 and the FGPG ₁₀ stored at step 334 (= FGPG ₁₀ −
FGPG ₁₁ ) is calculated. Bypass V
If there is no fixation abnormality in SV74, FGPG ₁₀
When the bypass VSV 74 has a sticking abnormality while the FGPG and the FGPG ₁₁ have a large deviation, there is no large deviation between them.

In step 342, it is determined whether or not the absolute value of ΔFGPG ₁₂ is smaller than a predetermined value α ₂ .
The predetermined value alpha ₂ is a predetermined value alpha ₁ following tiny value used in the first embodiment. | ΔFGPG ₁₂ |
<When α ₂ is not satisfied, ie, | ΔFGPG ₁₂ |
If ≧ α ₂ holds, it can be determined that the vapor concentration has shifted to a higher side by communicating the surge tank and the canister 62 after a large amount of fuel has been adsorbed by the canister 62. In this case, it can be determined that no fixation abnormality has occurred in the bypass VSV 74. Therefore, | ΔFGPG ₁₂ | <α
If it is determined that ₂ does not hold, then step 34
4 is executed.

On the other hand, when | ΔFGPG ₁₂ | <α ₂ holds, even if a large amount of fuel is adsorbed from the fuel tank 22 to the canister 62, the vapor concentration does not change before and after the supply of the drive signal to the bypass VSV 74. I can judge. In this case, it can be determined that a fixation abnormality has occurred in the bypass VSV 74. Therefore, when such a determination is made, the process of step 346 is performed next.

At Step 344, the bypass VSV 74
Process of resetting is executed bypass VSV abnormality flag FLAG ₁ indicating that the fixation abnormality has occurred in. In step 346, the bypass VSV abnormality flag FLAG
_The process of setting ₁ is executed. Step 344 above
Alternatively, when the process of 346 ends, the current routine ends.

According to the above-described processing, when the determination of the fixation abnormality of the bypass VSV 74 is suspended in the process of introducing the negative pressure to the evaporative system by detecting the evaporative system hole, the sufficient fuel is adsorbed to the canister 62. Based on the vapor concentration after the standby, it is possible to determine whether there is a fixation abnormality of the bypass VSV 74. For this reason, according to the present embodiment, whether the vapor concentration has not changed due to the fixation abnormality of the bypass VSV 74, or whether the vapor concentration of the air chamber 30 is low under the condition that the bypass VSV 74 functions normally. It can be distinguished that the vapor concentration does not change due to this. Therefore, according to the fuel storage device of the present embodiment,
Even when the vapor concentration of the gas from the canister 62 is low, the fixation abnormality of the bypass VSV 74 can be accurately determined.

[0119]

As described above, according to the first, second, and fourth aspects of the present invention, it is possible to sufficiently secure a period for purging the fuel adsorbed on the canister. According to the third aspect of the present invention, even when the internal pressure of the air chamber changes, the negative pressure can be properly introduced into the evaporative system.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a fuel storage device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of calculating a vapor concentration correction coefficient FGPG.

FIG. 3 is a diagram for explaining an operation when the evaporation system hole is detected in the system according to the embodiment.

FIG. 4 is a diagram showing a comparison result of a vapor concentration correction coefficient FGPG between a case where a hole is formed in the bladder film and a case where no hole is formed in the system of the present embodiment.

FIG. 5 is a time chart for explaining the operation of the system of the embodiment.

FIG. 6 is a flowchart of an example of a control routine executed to perform bladder membrane hole detection at the time of introducing a negative pressure for evaporative system hole detection in the fuel storage device of the present embodiment.

[7] for determining whether a hole in the bladder membrane in the present embodiment, and shows a map representing the relationship between ΔFGPG and FGPG _1.

FIG. 8 is a diagram schematically illustrating a drive mechanism of a vehicle equipped with a fuel storage device according to a second embodiment of the present invention.

FIG. 9 is a flowchart of an example of a control routine executed to perform bladder membrane hole detection at the time of introducing a negative pressure for evaporative system hole detection in the fuel storage device of the present embodiment.

FIG. 10 is a flowchart of an example of a control routine executed in a vehicle equipped with the fuel storage device of the embodiment.

FIG. 11 is a flowchart of an example of a control routine executed in a fuel storage device according to a third embodiment of the present invention.

FIG. 12 is a flowchart of an example of a control routine executed in a fuel storage device according to a fourth embodiment of the present invention.

FIG. 13 is a flowchart of an example of a subroutine executed when the detection of the fixation abnormality of the bypass VSV is suspended in the fuel storage device of the present embodiment.

[Explanation of symbols]

 Reference Signs List 20 electronic control unit (ECU) 22 fuel tank 24 internal combustion engine 26 bladder membrane 28 fuel chamber 30 air chamber 34 intake passage 44 canister close valve (CCV) 46 tank internal pressure sensor 62 canister 64 purge passage 68 purge VSV 72 bypass passage 74 Bypass VSV

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Naoya Takagi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3D038 CA22 CA26 CC02 CC05 CD05 CD18

Claims (4)

[Claims] 1. A fuel tank separated into a fuel chamber and an air chamber by a separation membrane, an evaporative gas treatment mechanism for purging evaporated fuel from the fuel tank to an intake passage via a canister, and a negative pressure for an evaporative system. A hole detecting means for detecting holes in the evaporative system by filling, and a gas from the fuel chamber to the air chamber by directly purging gas in the air chamber into the intake passage bypassing the canister. A fuel storage device comprising: fuel leak detection means for detecting fuel leakage; wherein the fuel leak detection means detects fuel leakage when the negative pressure is introduced by the hole detection means. 2. A fuel tank, which is separated into a fuel chamber and an air chamber by a separation membrane, and an evaporative gas processing mechanism for purging evaporated fuel from the fuel tank to an intake passage via a canister, wherein a predetermined condition is satisfied. In a fuel storage device capable of executing a communication path switching control for shutting off a communication path between the canister and the intake passage when the condition is satisfied, when the stop condition of the internal combustion engine is satisfied, the communication path is established after the stop condition is satisfied. A fuel storage device comprising: engine control means for stopping the internal combustion engine after a lapse of a period in which the fuel is shut off. 3. The fuel storage device according to claim 1, wherein a purge control valve provided in a communication passage between the canister and the intake passage; an air chamber pressure detection means for detecting an internal pressure of the air chamber; An opening control means for controlling the opening of the purge control valve based on the detection result of the air chamber pressure detecting means. 4. The fuel storage device according to claim 1, further comprising: a switching valve configured to switch between a conduction state between the intake passage and the canister and a conduction state between the intake passage and the air chamber. A fuel storage device for diagnosing a failure of the switching valve based on a comparison result of an evaporative fuel concentration downstream of the switching valve before and after the switching of the switching valve when negative pressure is introduced by the means;