JP2002202008A - Fault diagnostic device for evaporative fuel processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fault diagnostic device for an evaporative fuel processing device capable of detecting both of the leakage and a blocking state (clogging) of evaporative fuel in a fuel supplying passage between a fuel tank and an intake line. SOLUTION: This fault diagnostic device 14 is applied to an evaporative fuel processing device 1 making a canister 4 adsorbing evaporative fuel in the fuel tank 2 through a first fuel supplying passage 6, and supplying the evaporative fuel adsorbed by the canister into an intake passage 12 through a second fuel supplying passage 10 provided with a purge valve 8. The fault diagnostic device 14 comprises an electric pump 28 closing the purge valve and pressurizing a space between the fuel tank and the purge valve when a specified fault diagnostic condition is satisfied during stopping of an engine, a leakage diagnostic means 32 diagnosing the presence or absence of the leakage of the evaporative fuel from the amount of change in a load current value I of the electric pump, and a blocking state detecting means 32 temporary opening the purge valve at the time of pressurizing by the electric pump and detecting a blocking state occurred in the first or second fuel supplying passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure diagnosis apparatus for an evaporative fuel processing apparatus, and more particularly, to an evaporative fuel in a fuel tank which is adsorbed by a canister, and the evaporative fuel adsorbed by the canister is purged to purify an intake system. The present invention relates to a failure diagnosis device for an evaporative fuel processing device to be supplied to a vehicle.

[0002]

2. Description of the Related Art Conventionally, in an evaporative fuel processing apparatus for an engine (internal combustion engine), evaporative fuel generated in a fuel tank is temporarily adsorbed to a canister, and the adsorbed evaporative fuel is released (purged) under predetermined engine operating conditions. ), The purged air-fuel mixture mixed with the purge air is sucked into the intake system (intake passage) of the engine while controlling the flow rate by the purge valve, thereby preventing the fuel vapor from being released into the atmosphere. I have. On the other hand, if there is a crack in the middle of the piping of the evaporative fuel supply device or if there is a poor seal at the joint of the piping, if the evaporative fuel leaks from these locations, the evaporative fuel is released into the atmosphere and the evaporative fuel is released. This is not preferable because the original function of the processing device is not performed.

[0003]

Therefore, conventionally, as described in Japanese Patent Application Laid-Open No. H11-336620, for example, in order to prevent such a leakage of fuel vapor, a fuel tank is provided after the engine is stopped. The inside of the evaporative fuel supply passage is pressurized in a state where the evaporative fuel supply passage leading to the intake system is sealed, and the presence or absence of the leak is diagnosed by detecting a parameter that changes depending on the presence or absence of the leak at the time of pressurization. 2. Description of the Related Art A failure diagnosis device for an evaporative fuel treatment device is known. However, the conventional failure diagnosis device described in this publication is effective for diagnosing the presence or absence of a leak of the evaporative fuel generated in the evaporative fuel supply passage. If a blockage (clogging) occurs between the systems, the blockage cannot be detected. Therefore, in addition to detecting the presence or absence of a fuel vapor leak, a failure diagnostic device capable of detecting a blocked state (clogging) between the fuel tank and the canister and between the canister and the intake system is provided for the evaporated fuel processing device. Has been requested.

SUMMARY OF THE INVENTION The present invention has been made to satisfy a conventional demand, and is capable of detecting both a leak and a clogged state (clogging) of evaporated fuel in a fuel supply passage between a fuel tank and an intake system. It is an object of the present invention to provide a failure diagnosis device for an evaporated fuel processing device that can be used.

[0005]

In order to achieve the above object, fuel vapor in a fuel tank is adsorbed to a canister via a first fuel supply passage, and the fuel vapor adsorbed by the canister is purged by a purge valve. A failure diagnosis device for an evaporative fuel processing device that supplies a fuel to an intake system via a second fuel supply passage provided with a purge valve that closes a purge valve when a predetermined failure diagnosis condition is satisfied. Pressurizing means for pressurizing the space, and at the time of pressurization by the pressurizing means, based on the amount of change in a parameter related to the leakage of fuel vapor,
Leak diagnosis means for diagnosing the presence or absence of a fuel vapor leak;
The purge valve is temporarily opened at the time of pressurization by the pressurizing means, and the closed state occurring in the first fuel supply passage or the second fuel supply passage is determined based on the amount of change in the parameter when the purge valve is in the open state. And a closed state detecting means for detecting.

In the present invention configured as described above,
When the predetermined failure diagnosis condition is satisfied, the pressurizing means closes the purge valve and pressurizes the space from the fuel tank to the purge valve. Based on the amount of change of the related parameter, it is diagnosed whether or not the fuel vapor leaks. further,
The closed state detecting means opens the purge valve temporarily when pressurizing by the pressurizing means, and based on the amount of change of the parameter when the purge valve is in the open state, the closed state detecting means is connected to the first fuel supply passage or the second fuel supply passage. Detect the blocking condition that has occurred.

In the present invention, preferably, the closed state detecting means detects the closed state of the second fuel supply passage when the change amount of the parameter is equal to or less than the first set value, and the change amount of the parameter is set to the first set value. When the value is equal to or more than a second set value larger than the value, the closed state of the first fuel supply passage is detected.

According to the present invention, the fuel vapor in the fuel tank is first removed.
The fuel vapor is adsorbed to the canister via the fuel supply passage, and the evaporated fuel adsorbed to the canister is discharged to the second canister provided with the purge valve.
A failure diagnosis device for an evaporative fuel processing device that supplies a fuel to a suction system via a fuel supply passage, wherein when a predetermined failure diagnosis condition is satisfied, a purge valve is closed and a pressure from a fuel tank to a purge valve is pressurized. Means, a leak diagnosing means for diagnosing the presence or absence of a leak of evaporative fuel based on an amount of change of a parameter related to a leak of evaporative fuel at the time of pressurization by the pressurizing means, and a parameter change at the time of pressurization by the pressurizing means. Closed state detecting means for detecting a closed state of the first fuel supply passage when the amount is larger than a predetermined determination value.

In the present invention configured as described above,
When the predetermined failure diagnosis condition is satisfied, the pressurizing means closes the purge valve and pressurizes the space from the fuel tank to the purge valve.
Based on the amount of change in the parameter related to the evaporative fuel leak, the presence / absence of the evaporative fuel leak is diagnosed. The closed state of the first fuel supply passage is detected.

Preferably, the present invention further comprises a fuel remaining amount detecting means for detecting a fuel remaining amount in the fuel tank, and a space volume in the fuel tank based on the fuel remaining amount detected by the fuel remaining amount detecting means. And a judgment value setting means for setting a predetermined judgment value based on the space volume. In the present invention, preferably, the pressurizing means is an electric pump,
The parameter of the leak diagnosis means is at least one of the electric current and the rotation speed of the electric pump. In the present invention, preferably, the parameter of the leak diagnosis means is a pressure in the fuel vapor treatment device.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, a failure diagnosis device for an evaporative fuel treatment device according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram showing a failure diagnosis device for an evaporative fuel treatment device according to a first embodiment of the present invention, and FIG. 2 is a time chart showing the contents of the failure diagnosis according to the first embodiment. First, as shown in FIG. 1, reference numeral 1 denotes an evaporative fuel processing apparatus, and the evaporative fuel processing apparatus 1 includes a canister 4 for adsorbing and collecting evaporative fuel generated in a fuel tank 2 with an adsorbent such as activated carbon. It has.
Here, the fuel tank 2 and the canister 4 are connected by a first fuel supply passage 6, and the canister 4 includes a purge valve 8 and is connected by a second fuel supply passage 10 to an intake passage 12 which is an intake system. I have.

Further, the evaporative fuel treatment apparatus 1 has a failure diagnosis apparatus 1 for detecting a leak and a blockage state described later.
4 are provided as follows. First, canister 4
A first air passage 16 is provided at the bottom of the first air passage 16, and an upstream side of the first air passage 16 is branched into three passages of a second air passage 18, a third air passage 20, and a fourth air passage 22. . An air filter 24 is provided upstream of the second air passage 18.
The air (air) can be introduced from outside through the air filter 24. The fourth air passage 22 is provided with a reference orifice 26 having a reference diameter, for example, a diameter of 0.02 inches (about 0.5 mm), and its upstream side merges with the third air passage.
On the upstream side of the third air passage 20, there is provided an electric pump 28 which merges with the second air passage and has a constant rotation speed.

An electromagnetic switching valve 30 for switching between the second air passage 18 and the third intake passage 20 and the fourth air passage 22 is provided. In FIG. 1, the solid line indicates the open state of the switching valve 30, and the broken line indicates the closed state. As will be described later, the processing of the original evaporated fuel is performed in the open state during the start of the engine, and the failure diagnosis is performed in the closed state during the stop of the engine. On the other hand, the fuel tank 2 is provided with a fuel remaining amount detection sensor 31 for detecting the remaining amount of fuel in the fuel tank 2. The space volume inside is calculated. Further, reference numeral 32 denotes a control unit.
2 sends a control signal to the purge valve 8, the electric pump 28, and the switching valve 30 to detect a leak of evaporated fuel and a closed state (clogging) of the first fuel supply passage 6 and the second fuel supply passage 10 described later. It has become.

Next, before explaining the details of the failure diagnosis, normal processing of the fuel vapor will be described with reference to FIG. First, in a predetermined engine operating state, the switching valve 30 is opened (indicated by a solid line in FIG. 2), and the canister is externally passed through the second air passage 18 and the first air passage 16 via the air filter 24. Purge air is introduced into 4. At this time, the canister 4 temporarily adsorbs the evaporative fuel generated in the fuel tank 2, mixes the adsorbed evaporative fuel with the purge air to form a purge mixture, and the purge mixture is supplied to the purge valve 8. While controlling the flow rate, the intake air is sucked into the intake passage 12 of the engine. Thus, the fuel tank 2
By treating the evaporated fuel in the inside, the emission of the evaporated fuel to the atmosphere is prevented.

Next, referring to FIG. 2, the content of the failure diagnosis according to the first embodiment, in particular, the content of detecting the closed state (clogging) of the first fuel supply passage 6, and the first fuel supply passage 6 and the second fuel The details of detecting a leak of the evaporated fuel in the supply passage 10 will be described. The failure diagnosis according to the first embodiment is performed with the purge valve 8 closed. First, after the engine is stopped (time t ₀ ), the switching valve 30 is opened (the state shown by the solid line in FIG. 2). In this open state, the purge valve 8 is closed and the electric pump 28 is started, and the fourth air passage 22 is started. Introduce outside air toward. At this time, the discharge air from the electric pump 28 passes through a reference orifice 26 provided with a hole having a predetermined value and provided in the fourth air passage 22. At this time, the resistance of the introduced air passing through the reference orifice 26 is measured as the load current of the electric motor, and the average value of the load current between the time t ₀ and the predetermined time t ₁ is used to determine the leak (leak) at the time of leak diagnosis. The reference value of the reference load current (I
ref).

Next, as shown in FIG. 2, this reference value (I
ref) is a reference threshold (I _s1 ) that is a value larger by a predetermined value than
Set. Next, in this state, that is, in a state in which the purge valve 8 is closed, the switching valve 30 is switched to a closed state (shown by a broken line in FIG. 2) (time t ₁ ), and the operation of the electric pump 28 is continued. The operation of the electric pump 28 pressurizes the inside of the first fuel supply passage 6 and the second fuel supply passage 10 which are the evaporative fuel supply passages from the fuel tank 2 to the purge valve 8. Load current value of pump 28 (I)
Also rises. The load current value at time t ₁ is I ₀
And the pressure is close to the atmospheric pressure.

After time (t ₂ ), the load current values (I) corresponding to the pressures in the first fuel supply passage 6 and the second fuel supply passage 10 are shown in FIG. It changes as shown as Case 4 and Case 5.

[0018] First, the case 1, the time (t ₁₎ from the predetermined time (T (1)) in the time after a lapse (t _2), the time (t ₂₎ in the load current value I and time (t ₁ load current value is the difference between the load current value I ₀ in) (I-
If I ₀ ) is larger than the first threshold value (f1 (ftl)), it is estimated that such a sharp pressure increase has occurred because the space in the fuel tank 2 is not used, and the fuel tank 2 and the canister It is determined that the first fuel supply passage 6 during the period 4 is closed.

The first threshold value (f1 (ftl))
Is a value set based on the space volume in the fuel tank 2 calculated based on the fuel remaining amount detected by the fuel remaining amount detection sensor 31 described above. In addition, a second threshold (f2 (ftl)) and a third threshold (f
3 (ftl)), the fourth threshold (f4 (ftl)), and the fifth
Similarly, the threshold value (f5 (ftl)) is a value set based on the volume of space in the fuel tank 2. These thresholds are set to smaller values as the space volume is larger.

Next, the case 2, the time (t ₁₎ from the predetermined time (T (2)) in the time after a lapse (t _3), the load current value I and time at time (t ₂₎ (t load current value is the difference between the load current value I ₀ in ₁₎ (I-
I ₀₎ is smaller than the second threshold value (f2 (ftl)), and the load current value is the difference between the load current value I ₀ at time (t ₃₎ in the load current value I and time (t ₁₎ ( I-
I ₀ ) is smaller than the third threshold value (f3 (ftl)),
Since the pressures in the first fuel supply passage 6 and the second fuel supply passage 10 hardly increase, the leakage of the evaporated fuel to both or any one of the first fuel supply passage 6 and the second fuel supply passage 10 ( It is determined that a large leak has occurred.

Next, the case of the case 3, the time in (t ₁₎ from the predetermined time (T (2)) time after lapse (t _3), the load current value (I-I _0), the second threshold (F2 (ft
greater than l)), further, at time (t ₁₎ from the predetermined time (T (3)) time after lapse (t _4), the load current value (I-I ₀₎ is the third threshold value (f3 (ftl )) And if the reference threshold (I _s1 ) is not reached,
Although the pressures in the first fuel supply passage 6 and the second fuel supply passage 10 are higher than in the case 2, since the pressure has not yet reached the reference threshold value (I _s1 ) even at time (t ₄ ), It is determined that a leak (small leak) of the evaporated fuel has occurred in both or any one of the first fuel supply passage 6 and the second fuel supply passage 10.

In case 4 and case 5, the time (t
_{From 2} ) to time (t ₄ ), the load current value (I−I ₀ )
_Has reached the reference threshold value (I _s1 ), the pressures in the first fuel supply passage 6 and the second fuel supply passage 10 are increasing at a predetermined speed, and the first fuel supply passage 6 and the second It is determined that there is no leak of the evaporated fuel in the fuel supply passage 10.

As described above, in the first embodiment, the closed state (blockage) of the first fuel supply passage 6 between the fuel tank 2 and the canister 4 is detected. A large leak and a small leak of the evaporated fuel in the fuel supply passage 10 are detected.

Next, referring to FIG. 3, a description will be given of the details of the failure diagnosis according to the second embodiment, in particular, the details of detecting a blocked state (blockage) in the first fuel supply passage 6 and the second fuel supply passage 10. First, as in the case of the first embodiment, after the engine is stopped (time t ₀ ), the switching valve 30 is opened (the state shown by the solid line in FIG. 2). In this open state, the purge valve 8 is closed and the electric pump is closed. 28 is started, and outside air is introduced toward the fourth air passage 22. At that time, the electric pump 28
The air discharged from the air passage passes through a reference orifice 26 provided with a hole having a predetermined diameter and provided in the fourth air passage 22. The resistance of the introduced air passing through the reference orifice 26 at this time is measured as the load current of the electric motor, and the time t ₀
And the average value of the load current during the predetermined time t _1, to determine the reference value of the load current as a reference leak (leak) at the time of leakage diagnosis a (Iref). Next, in this state, that is, in a state in which the purge valve 8 is closed, the switching valve 30 is switched to a closed state (shown by a broken line in FIG. 2) (time t ₁ ), and the operation of the electric pump 28 is continued. By operation of the electric pump 28,
The first fuel supply passage 6 and the second fuel supply passage 10, which are the fuel supply passages from the fuel tank 2 to the purge valve 8, are pressurized. With this pressurized state, the load current value (I ) Also rises. Note that the load current value at time t ₁ is I _0, which is a pressure near the atmospheric pressure.

Next, as shown in FIG. 3, the reference value (Ire
f) Set a reference threshold (I _s1 ) that is a value larger by a predetermined value than f). The load current value (I) at the time (t ₂ ) when the load current value (I) exceeds the reference threshold value (I _s1 ) is defined as Im. At this time, the purge valve 8 is opened. Further, a load current value (I) at a time (t ₃ ) after a lapse of a predetermined time (Tb) from the time (t ₂ ) is defined as Icp. By the purge valve 8 opens Raku at time (t _2), the time (t ₂₎ after the load current value that corresponds to the pressure of the first fuel supply passage 6 and the second fuel supply passage 10 (I), as shown in FIG. At 3, change as shown as Case 1, Case 2, Case 3 and Case 4.

First, in case 1, although the purge valve 8 is opened at the time (t ₂ ), the load current value (I) is still increasing thereafter. , It is determined that the second fuel supply passage 10 is completely closed. In the case 2, the load current value (I) only slightly decreases after the time (t ₂ ), so that the case 2 has the cross section of the second fuel supply passage 10. It is determined that a part is in a closed state. Specifically, the load current value (Im) and the predetermined time (T
b) The load current value (Ic) at the time (t ₃ ) after the elapse
p) is equal to the fourth threshold value (f4 (ft)
l)) If it is smaller, it is determined to be Case 1 or Case 2.

Next, in case 4, the purge valve 8 is opened at time (t ₂ ), and thereafter, the load current value (I)
Is rapidly decreasing, so that Case 4
It is determined that the first fuel supply passage 6 is in the closed state. Specifically, the difference (Im−Icp) between the load current value (Im) and the load current value (Icp) at the time (t ₃ ) after the lapse of the predetermined time (Tb) is equal to the fifth threshold value (f5 (ftl)). If it is larger, it is determined that this is case 4.

Further, in case 3, the time (t ₂ )
At this time, the purge valve 8 is opened, and thereafter, the load current value (I) decreases normally, so that the case 3 is closed in both the first fuel supply passage 6 and the second fuel supply passage 10. Is determined to be normal without any error. Specifically, the difference (Im-Icp) between the load current value (Im) and the load current value (Icp) at the time (t ₃ ) after the lapse of the predetermined time (Tb) is equal to the fourth threshold value (f4 (ftl)). If it is larger and smaller than the fifth threshold value (f5 (ftl)),
Case 3 is determined.

After detecting the closed state (clogging) in the first fuel supply passage 6 and the second fuel supply passage 10 in this manner, in the case 3 and the case 4, the purge valve 8
Is open until the load current value reaches I _{0 in} order to prevent the HC from flowing out to the atmosphere when the pressurized air is released, and the pressurized air is released into the intake passage 12 and the load current value becomes I ₀ . (Case 4 closes at time t ₄ , case 3 closes at time t ₅ ). In case 1 and case 2, the load current value does not reach I ₀ even after the lapse of the predetermined time (T (4)), so that the predetermined time (T (4))
At the time (t ₆ ), the purge valve 10 is closed.

Next, referring to FIG. 4 to FIG. 6, a description will be given of the failure diagnosis contents executed by the control unit 32, including both the first embodiment and the second embodiment described above. 4 to 6, S indicates a step. S1 to S in the flowcharts shown in FIGS.
31 corresponds to the first embodiment (see FIG. 2), and S32 to S48 in the flowchart shown in FIG. 6 correspond to the second embodiment (see FIG. 3).

First, as shown in FIGS. 4 and 5, in S1, the vehicle state is detected. Specifically, a state where the engine is stopped is detected. In S2, it is determined whether a predetermined failure diagnosis condition is satisfied. Specifically, the operating state immediately before the stop of the engine is stored,
For example, when a predetermined time or a predetermined distance has been traveled,
Thereafter, conditions for performing the fault diagnosis once a day are set. If YES in S2, a failure determination timer Tm is set to 0 in S3, and the electric pump is started in S4. In S5, the reference value (Iref) of the load current value is measured. Thereafter, in S6, and closed the switching valve 30 from the opened state, it detects a load current value I ₀ at that time. S7
Then, it is determined whether the failure determination timer Tm is equal to the determination threshold T (1). If NO, the failure determination timer Tm is incremented by 1 in S8. If YES, the load current is determined in S9. The value I is detected.

At S10, the load current value I and the load current value I ₀
The load current value (I−I ₀ ) that is the difference between the first threshold value f1 (f
tl) It is determined whether or not it is smaller. If NO, S
In step S11, it is determined that a blockage failure (blockage state) has occurred between the fuel tank and the canister (the first fuel supply passage 6). Is stopped, and the failure diagnosis ends.

If YES in S10, the process proceeds to S13, where it is determined that there is no blockage failure (blockage state) between the fuel tank and the canister (first fuel supply passage 6), and in S14, the load current value (I-I) is determined. ₀ ) is larger than a second threshold value f2 (ftl) (large leak threshold value). If NO, the process proceeds to S15, where the failure determination timer Tm sets the predetermined value T
(2) It is determined whether or not it is the above, and if NO, in S15,
One is added to the failure determination timer Tm. If YES, detects a load current value I in S17, in S18, the load current value I and the load current value load current value is the difference of I ₀ (I-
I ₀ ) is determined to be greater than or equal to a second threshold value f2 (ftl) (small leak threshold value). If NO, S
Proceed to 19 to determine the occurrence of a large leak. Then, S
At 20, the switching valve is changed from the closed state to the open state, the electric pump is stopped, and the failure diagnosis ends.

If YES in S14 or YES in S18, there is a possibility of a small leak. Therefore, in S21, it is detected that the vehicle state, for example, the remaining fuel amount is a predetermined value or more. Next, in S22, it is determined whether or not the small leak diagnosis condition, for example, the remaining fuel amount is equal to or more than a predetermined value. If NO, the process proceeds to S20, and the failure diagnosis is ended. Proceeding to S23, the reference threshold value Is1 is set to "Iref
* A predetermined value is set, 1 is added to the failure determination timer Tm in S24, and the load current value I is detected in S25. next,
Proceeding to S26, it is determined whether the load current value (I−I ₀ ), which is the difference between the load current value I and the load current value I ₀ , is equal to or greater than the reference threshold Is1, and if NO, the flow proceeds to S27. It is determined whether or not the failure determination timer Tm is equal to or greater than a predetermined value T (3). If YES, the process proceeds to S28, where it is determined whether a small leak has occurred. Then, in S29, the switching valve is changed from the closed state to the open state, the electric pump is stopped, and the failure diagnosis ends.

In the case of YES in S26, the process proceeds to S30, where it is determined that neither large leak nor small leak has occurred and that it is normal. Thereafter, in S31, the leak determination is cleared.

Next, as shown in FIG. 6, the blockage determination timer Th is set to 0 in S32. In S33, the load current value I detected in S25 is set to Im. In S34, the purge valve is opened from the closed state. Blockage determination timer T in S35
Add 1 to h. In S36, it is determined whether or not the blockage determination timer Th is equal to or more than a predetermined value Tb. If NO, 1 is further added. If YES, the process proceeds to S37, where the load current value Icp is detected.

Next, in S38, the difference between the load current value Im when Th = 0 and the load current value Icp when Th = Tb is larger than the blockage determination threshold value (the fourth threshold value f4 (ftl)). If NO, it is determined in S39 that the second fuel supply passage 10 between the canister and the intake passage is closed, and if YES, the second fuel supply passage 10 is closed in S40. It is determined that it is not.

Next, in S41, the difference between the load current value Im and the load current value Icp is determined by the blockage determination threshold value (fifth threshold value f5 (f
tl)) It is determined whether it is smaller. If NO
In S42, it is determined that the first fuel supply passage 6 between the fuel tank and the canister is in a closed state.
At 3, it is determined that the first fuel supply passage 6 is not in the closed state.

Next, in S44, the blockage determination timer Th is set to 1
Addition to, detecting a load current value I at S45, determines whether or not the load current value I is equal to the load current value I ₀ in S46, N
If O, the process proceeds to S47. In S47, it is determined whether the failure determination timer Th is equal to or greater than a predetermined value T (4). N
If O, the process returns to S44, and 1 is further added. If YES, the process proceeds to S48, where the barge valve is closed from the open state.
In S49, the switching valve is changed from the closed state to the open state, the electric pump is stopped, and the failure diagnosis ends.

In the above-described embodiment, the electric pump has a constant rotation speed, and the load current value changes due to a change in the internal pressure of the first fuel supply passage 6 and the second fuel supply passage 10. However, the present invention is not limited to this. For example, the current and voltage may be constant, and the rotation speed of the electric pump may be changed due to a change in the internal pressure. In this case, the first fuel supply passage 6 and the second
The closed state of the fuel supply passage 10 and the leakage of the evaporated fuel are detected. Further, unlike the above-described embodiment, a sensor for detecting the internal pressure is provided in the evaporative fuel processing device such as a fuel tank instead of the load current value of the electric pump. The leak and the closed state of the fuel supply passage may be detected.

[0041]

As described above, according to the failure diagnosis apparatus for an evaporative fuel treatment apparatus of the present invention, both the leakage and the clogged state (clogging) of the evaporative fuel in the fuel supply passage between the fuel tank and the intake system. Can be detected.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a failure diagnosis device for an evaporative fuel treatment device according to a first embodiment of the present invention.

FIG. 2 is a time chart showing a failure diagnosis content according to the first embodiment of the present invention.

FIG. 3 is a time chart showing a failure diagnosis content according to a second embodiment of the present invention.

FIG. 4 is a flowchart (first part) showing the contents of failure diagnosis executed according to the first and second embodiments of the present invention.

FIG. 5 is a flowchart (second part) showing the contents of failure diagnosis executed according to the first and second embodiments of the present invention.

FIG. 6 is a flowchart (third part) showing the contents of failure diagnosis executed according to the first and second embodiments of the present invention.

[Description of Signs] 1 Evaporated fuel processing device 2 Fuel tank 4 Canister 6 First fuel supply passage 8 Purge valve 10 Second fuel supply passage 12 Intake passage (intake system) 14 Failure diagnostic device 16 First air passage 18 Second air Passage 20 Third air passage 22 Fourth air passage 24 Air filter 26 Reference orifice 28 Electric pump 30 Switching valve 31 Fuel remaining amount detection sensor 32 Control unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Katsuhiko Sakamoto 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Seiji Makimoto 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Stock In-house F term (reference) 3G044 BA22 CA02 DA02 DA07 EA18 EA33 FA20 FA23 FA39 FA40 GA26 GA28

Claims (6)

[Claims] An evaporative fuel in a fuel tank is adsorbed on a canister via a first fuel supply passage, and the evaporative fuel adsorbed on the canister is taken in via a second fuel supply passage provided with a purge valve. Pressurizing means for closing a purge valve and pressurizing a space from a fuel tank to a purge valve when predetermined fault diagnostic conditions are satisfied; At the time of pressurization, the leak diagnostic means for diagnosing the presence or absence of the leak of the evaporated fuel based on the amount of change of the parameter related to the leak of the evaporated fuel, and the purge valve is temporarily operated at the time of pressurization by the pressurizing means. A closed state detecting means for detecting a closed state occurring in the first fuel supply passage or the second fuel supply passage based on the amount of change of the parameter when the purge valve is opened and the purge valve is opened. A fault diagnosis device for an evaporative fuel treatment device, comprising: a stage; 2. The closed state detecting means detects a closed state of the second fuel supply passage when a change amount of the parameter is equal to or less than a first set value, and the change amount of the parameter is set based on the first set value. 2. The failure diagnosis device for an evaporative fuel treatment device according to claim 1, wherein the first fuel supply passage is detected when the second fuel supply passage is larger than a second set value. 3. An evaporative fuel in a fuel tank is adsorbed on a canister via a first fuel supply passage, and the evaporative fuel adsorbed on the canister is suctioned via a second fuel supply passage provided with a purge valve. A pressurizing means for closing a purge valve and pressurizing a space from a fuel tank to a purge valve when a predetermined fault diagnosis condition is satisfied; A leak diagnosing means for diagnosing the presence or absence of a leak of the fuel vapor based on a change amount of a parameter relating to the leak of the fuel vapor at the time of pressurization; And a closed state detecting means for detecting a closed state of the first fuel supply passage when the value is larger than a determination value. 4. A fuel remaining amount detecting means for detecting a fuel remaining amount in the fuel tank, and a space volume in the fuel tank is calculated based on the fuel remaining amount detected by the fuel remaining amount detecting means. 4. The failure diagnosis device for an evaporative fuel treatment apparatus according to claim 3, further comprising: a determination value setting unit configured to set the predetermined determination value based on the space volume. 5. The method according to claim 1, wherein the pressurizing unit is an electric pump, and the parameter of the leak diagnosis unit is at least one of a current and a rotation speed of the electric pump. A failure diagnosis device for the fuel vapor treatment device according to any one of the preceding claims. 6. The failure diagnosis apparatus for an evaporative fuel treatment apparatus according to claim 1, wherein the parameter of the leak diagnosis means is a pressure in the evaporative fuel treatment apparatus.