JP2002180916A - Failure diagnostic device for vaporized fuel treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a leak of fuel from a fuel tank 2 when the leak is diagnosed with a vaporized fuel supply system to be pressurized, in a failure diagnostic device for a vaporized fuel supplying device. SOLUTION: A load current value of an electric pump 20 changed by whether a leak exists or not of vaporized fuel from a vaporized fuel supply system, when it is pressurized by the electric pump 20, is made to serve as a diagnostic parameter Im-Io. A condition of abnormality in the vaporized fuel supply system is diagnosed to be based on this diagnostic parameter Im-Io, on the other hand, a diagnosis is inhibited when an inhibition condition is detected that a vehicle tilt angle is a prescribed value or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a failure diagnosis device for diagnosing an abnormality in a device for processing fuel vapor of an internal combustion engine.

[0002]

2. Description of the Related Art In recent years, importance has been placed on technologies that contribute to the protection of the natural environment. For example, in the case of automobiles and the like having an internal combustion engine, it is necessary to prevent vaporized fuel generated in a fuel tank or the like from being released into the atmosphere. Technology to prevent air pollution is essential. As this technique, a fuel vapor treatment device for an internal combustion engine as disclosed in, for example, Japanese Patent Application Laid-Open No. 5-215020 has been known.

In this apparatus, fuel vapor generated in a fuel tank or the like is temporarily adsorbed to a canister, and the adsorbed fuel vapor is released from the canister under predetermined engine operating conditions, mixed with air for purging, and purged. By controlling the flow rate of the air-fuel mixture with the purge control valve and performing suction processing on the intake system of the engine, evaporation of the evaporated fuel into the atmosphere is prevented.

By the way, in the above-mentioned apparatus, if a crack is generated in the middle of the fuel vapor pipe or a seal failure occurs at the joint of the fuel vapor pipe, the fuel vapor is diffused into the atmosphere from the leak portion. As a result, the original effect of preventing radiation cannot be sufficiently exhibited.

Therefore, conventionally, various devices for diagnosing the presence or absence of such a leak of the fuel vapor have been proposed.
One known method is to diagnose the presence / absence of a leak based on a pressure change in the closed evaporative fuel supply system after the operation of the engine is stopped. In this method, for example, after a determination level is set based on a drive current of an electric pump when air is pumped from an electric pump through a reference orifice having a reference diameter, the reference fuel orifice is bypassed and the evaporative fuel treatment apparatus is bypassed. The present invention compares the drive current of the electric pump when the air is pumped into the pipe to be leak-diagnosed by the electric pump with the set determination level, thereby diagnosing the presence or absence of a leak of the fuel vapor. Specifically, when the drive current is smaller than the determination level, it is diagnosed that the fuel vapor leak has occurred.
That is, when a leak amount larger than the leak amount when the hole corresponding to the reference orifice is generated, the drive current of the electric pump decreases from the determination level due to a decrease in the air pumping load. It can diagnose the presence or absence of a leak.

[0006]

By the way, a filler cap is provided at the filler port of the fuel tank, and the filler port is sealed with the filler cap to prevent fuel from leaking from the filler port. The filler cap may be loose, or the seal member between the filler cap and the filler may be deteriorated.

On the other hand, when diagnosing the presence or absence of a leak, the vehicle may be inclined. In this case, depending on the degree of inclination of the vehicle and the remaining amount of fuel in the tank, the level of the fuel in the fuel tank may increase. May reach near the filler cap.

In such a state, when the evaporative fuel supply system is pressurized in order to diagnose the presence or absence of a leak in the evaporative fuel supply system, the oil pressure in the fuel tank is pushed by the pressure and reaches the vicinity of the filler cap. Oil level of the fuel
There is a risk that fuel will leak from the filler port.

The present invention has been made in view of the above points, and an object of the present invention is to provide a failure diagnosis apparatus for an evaporative fuel supply device as described above by improving the structure of the evaporative fuel supply device. An object of the present invention is to prevent the fuel from leaking from the fuel tank at the time of diagnosis of pressurizing the system.

[0010]

In order to achieve the above object, according to the present invention, a purge valve provided between a fuel tank and a fuel tank and an internal combustion engine when a predetermined diagnostic condition is satisfied. Pressurizing means for pressurizing the evaporative fuel supply system leading to the evaporative fuel supply system. Diagnostic means for diagnosing an abnormal state of the evaporative fuel supply system, and detecting means for detecting a predetermined prohibition condition in which the oil level of the fuel tank in the fuel tank is closer to the filler cap of the fuel tank than normal. A diagnosis prohibiting unit for prohibiting the diagnosis by the diagnosis unit when the prohibition condition is detected by the detection unit.

With the above arrangement, the prohibition condition is detected to detect whether the oil level of the fuel in the fuel tank has reached the vicinity of the filler cap. When the prohibition condition is detected, the evaporative fuel supply system is added. Because it prohibits pressure
Even if the filler cap is loose or the seal member between the filler port is deteriorated, the fuel level reaching the vicinity of the filler cap is prevented from rising and the fuel is prevented from leaking from the filler port. be able to.

[0012] In the second aspect of the present invention, the prohibition condition is set when the inclination angle of the vehicle becomes a predetermined value or more. Also,
According to the third aspect of the invention, the prohibition condition is that the pressure in the fuel tank becomes equal to or higher than a predetermined value. In the invention of claim 4, the prohibition condition is that the fuel level in the fuel tank becomes equal to or higher than a predetermined value. These claims 2
According to the fourth to fourth aspects, desirable prohibition conditions can be embodied.

According to a fifth aspect of the present invention, there is provided a reference orifice having a reference diameter between the evaporative fuel supply system and the pressurizing means. The system is configured to diagnose an abnormality in the evaporative fuel supply system by comparing with a reference parameter obtained by pressurizing the system leading to the orifice. This makes it possible to effectively detect a hole in the fuel vapor supply system corresponding to the reference diameter of the reference orifice.

According to a sixth aspect of the present invention, the pressurizing means is an electric pump, and the diagnostic parameter is at least one of a current value and a rotation speed of the electric pump. In the invention according to claim 7, the diagnostic parameter is a pressure in a fuel tank.

According to the inventions of claims 6 and 7, desirable diagnostic parameters can be specifically obtained.

[0016]

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 schematically shows an outline of an evaporative fuel processing device provided in an internal combustion engine and a failure diagnosis device thereof. FIG. 1 shows a state where the vehicle is inclined.

Reference numeral 2 denotes a fuel tank for storing fuel such as gasoline. A fuel supply port 2b which is a tip of a fuel supply pipe extending obliquely upward from a side wall of a fuel storage portion 2a of the fuel tank 2.
Are closed by the filler cap 3. The fuel tank 2 has a remaining amount sensor 22 for measuring the remaining amount of fuel.
Are provided, and output to the control unit 8 built in the microcomputer.

The evaporative fuel processing apparatus adsorbs and collects the evaporative fuel of the fuel generated in the fuel tank 2 via an evaporative fuel introduction passage 6 to an adsorbent such as activated carbon filled in a canister 4 as an adsorbing means. The fuel adsorbed by the adsorbent is supplied through a purge passage 7 to an intake passage (not shown) downstream of a throttle valve (not shown).

The purge passage 7 is provided with an electromagnetically driven purge control valve 5 controlled based on a control signal from a control unit 8. In addition, a piping system as described below is configured for the leak diagnosis of the evaporated fuel in the evaporated fuel processing device. That is, one end of the first passage 11 is connected to an air inlet opening at the bottom of the canister 4, and the other end is branched and connected to the second to fourth passages 12, 13, 14 via the switching valve 15. The second passage 12 and the third passage 13 are joined again and communicate with an air introduction passage 18 in which an air filter 17 is provided. Further, a second passage 1 between an evaporative fuel supply system from the fuel tank 2 to the purge control valve 5 provided between the fuel tank 2 and the internal combustion engine and an electric pump 20 described later.
2, one end of a fourth passage 14 in which a reference orifice 16 having a reference diameter of, for example, 0.5 mm is interposed, and the other end is connected to the switching valve 15 as described above.

The switching valve 15 is an electromagnetically driven valve that is controlled based on a control signal from the control unit 8, and closes the second passage 12 when the valve is open to close the first passage 11, the third passage The third passage 13 is closed in a closed state while the first passage 11, the second passage 12, and the fourth passage 14 are in a communicating state while the 13 and fourth passages 14 are in a communicating state.

Further, the fourth passage 14 in the second passage 12
An electric pump 20 that is operated by a motor 19 is interposed on the air filter 17 side of the connection portion with the electric pump 20. The electric pump 20 is controlled based on a control signal from the control unit 8 so that outside air introduced through the air filter 17 and the air introduction passage 18 is sent to the switching valve 15 through the second passage 12. The evaporative fuel supply system is configured to be pressurized when a predetermined diagnostic condition is satisfied.

The vehicle is provided with an inclination sensor 21 for detecting an inclination angle of the vehicle, that is, an angle at which the fuel storage portion 2a of the fuel tank 2 is inclined toward the filler port 2b. It has been made to be.

Although not shown, a rotational speed sensor for detecting the engine rotational speed, a water temperature sensor for detecting the water temperature, an air-fuel ratio sensor for detecting the air-fuel ratio based on the oxygen concentration in the exhaust gas and the like are provided. , Control unit 8
Performs air-fuel ratio feedback control by controlling the amount of fuel injected by a fuel injection valve (not shown) based on signals from these various sensors, and controls the purge control valve 5 under predetermined operating conditions. To perform a process of purging the fuel vapor into the intake system.

The failure diagnosis apparatus according to the present invention evaporates on the basis of a diagnostic parameter that changes depending on whether or not the fuel vapor leaks from the fuel vapor supply system when the fuel vapor supply system is pressurized by the electric pump 20. Diagnostic means for diagnosing an abnormal state of the fuel supply system is provided. Further, the diagnostic means compares the diagnostic parameter with a reference parameter obtained by pressurizing the system from the electric pump 20 to the reference orifice 16 by the electric pump 20 to detect an abnormality in the fuel vapor system. It is configured.

Further, the failure diagnosis device includes detection means for detecting a predetermined prohibition condition for prohibiting the diagnosis by the diagnosis means, and the prohibition condition is provided when the inclination angle of the vehicle becomes a predetermined value or more. I have to be. In the present embodiment, the control unit 8, the electric pump 20, and the like constitute diagnostic means, and the control unit 8, the inclination angle sensor 21, and the remaining amount sensor 22 constitute detecting means. Further, the control unit 8 and the like constitute diagnosis prohibition means.

Next, a routine for evaporative fuel leak diagnosis by the control unit 8 will be described with reference to the flowcharts of FIGS. In step S1 of FIG. 2, the vehicle state such as the remaining fuel amount ftl in the fuel tank 2 and the rotation speed and vehicle speed of the engine is detected. Then, the process proceeds to step S2, and based on the output of the inclination angle sensor 21, the vehicle inclination angle th
Read e. Then, in step S3, the vehicle inclination angle th
It is determined whether or not e is smaller than a predetermined value. That is, the predetermined value is the inclination angle of the vehicle such that the oil level of the fuel in the fuel tank 2 reaches the vicinity of the filler cap 3. Since the predetermined value differs depending on the remaining amount of fuel, the remaining amount sensor 22 and The control unit 8 calculates the predetermined value based on the outputs from both the inclination angle sensors 21.
If it is determined that the inclination angle of the vehicle is equal to or greater than the predetermined value (that is, if the prohibition condition that the inclination angle of the vehicle is equal to or greater than the predetermined value is satisfied), the diagnosis prohibiting unit performs the diagnosis prohibition by the diagnosis unit. The leak diagnosis is prohibited, and the process ends.

On the other hand, if the vehicle inclination angle is smaller than the predetermined value in step S3 (ie, if the prohibition condition is not satisfied), the process proceeds to step S4. This step S4
Then, it is determined whether or not the leak diagnosis execution condition is satisfied. Here, the leak diagnosis execution conditions are, for example, whether the internal combustion engine is stopped, whether the outside air temperature is within a predetermined temperature range, and whether the remaining fuel amount in the tank is within a predetermined range. Whether or not. When the condition for executing the leak diagnosis is not satisfied, the process of the leak diagnosis is terminated. On the other hand, when the condition is satisfied, the process proceeds to step S5.

In step S5, the value of the failure determination timer Tm is reset to 0. Continue with step S6
In step S7, the motor 19 is operated by the control unit 8 to turn on the electric pump 20. Further, in step S7, the switching valve 15 is opened, and air is pumped from the electric pump 20 to the reference orifice 16, and the electric The load current threshold value Iref of the pump 20 is measured. Then, the process proceeds to step S8, where the switching valve 15 is closed, and the load current initial value Io of the electric pump 20 at that time is detected.

Thereafter, in step S9, it is determined whether or not the failure determination timer Tm is equal to or greater than a determination threshold T (1). If it is smaller than the determination threshold value T (1), the process proceeds to step S10, where the timer value is increased by 1, and the process again proceeds to step S9. That is, when the failure determination timer value Tm is T
(1) The timer value is incremented in step S10 until the timer value becomes equal to or more than 1 and the timer value Tm is set to T in step S9.
(1) If it becomes the above, the process proceeds to step S11. Then, in step S11, after detecting the load current value Im at that time (when the timer value of the failure determination timer Tm is T (1)), the process proceeds to step S12.

In step S12, the difference Im-Io between the load current value Im and the load current initial value Io is determined by the difference Ire between the fuel tank remaining amount ftl, the threshold value Iref, and the initial value Io.
f1 (ftl, I), which is a threshold value determined based on f-Io and determining that a relatively large leak has occurred.
ref-Io). That is, Im-Io is a diagnostic parameter, and changes depending on whether or not there is a leak from the evaporative fuel supply system when the electric fuel pump 20 pressurizes the evaporative fuel supply system. In the present embodiment, the diagnostic parameters are based on the load current value of the electric pump 20. For example, when there is a leak, the load on the electric pump 20 is smaller than when there is no leak, so the load current value is smaller. . Also, the load current value decreases as the leak increases. When it is determined that Im-Io is equal to or less than f1 (ftl, Iref-Io), the process proceeds to step S13.

In step S13, a failure determination timer Tm
Is greater than or equal to a predetermined determination threshold T (2). When it is smaller than the determination threshold value T (2), the process proceeds to step S14, the timer value is increased by 1, and the process again proceeds to step S13. That is, the timer value is incremented in step S14 until the failure determination timer value Tm becomes equal to or more than T (2), and the timer value Tm is incremented in step S13.
Is greater than or equal to T (2), the process proceeds to step S15. Then, after detecting the load current value Im at that time (when the timer value of the failure determination timer Tm is T (2)) in step S15, the process proceeds to step S16.

In step S16, a diagnostic parameter Im-I which is a difference between the load current value Im and the load current initial value Io is obtained.
o is determined based on the fuel tank remaining amount ftl and the difference Iref-Io between the threshold value Iref and the initial value Io, and is relatively large (for example, when there is a hole having a diameter of about 1.0 mm). Is determined to be greater than f2 (ftl, Iref-Io), which is a threshold value for determining that a leak has occurred. When it is determined that Im-Io is equal to or less than f2 (ftl, Iref-Io), the process proceeds to step S17. Then, step S1
7, it is determined that there is a relatively large leak in the fuel vapor supply system, and in step S18, the switching valve 15
Is changed from the closed state to the open state, the electric pump 20 is turned off, and the leak diagnosis process is terminated.

On the other hand, in step S12, the diagnostic parameter I
m-Io is the threshold value f1 (ftl, Iref-Io)
When it is determined that the threshold value is larger than the threshold value and in step S16, the diagnostic parameter Im-Io is set to the threshold value f2 (ftl,
Iref-Io), it is determined that
The process proceeds to step S19.

In step S19, Is1 which is a threshold value for stopping the pressurization by the current pump 20 is calculated by multiplying Iref measured in step S7 by a predetermined value. This Is1 is a reference parameter obtained by pressurizing the system from the electric pump 20 to the reference orifice 16, and this reference parameter Is1 and the diagnostic parameter I
By comparing with m-Io, abnormality of the evaporative fuel supply system is diagnosed. After calculating the reference parameter Is1, the process proceeds to step S20.

In step S20, a filler cap leakage prevention threshold value fcap1 which is a threshold value determined according to the vehicle inclination angle the and the remaining fuel amount ftl in the fuel tank.
(The, ftl) is set. This threshold value fcap
1 (the, ftl) is a limit value at which fuel may leak from the filler cap.

Subsequently, in step S21, after increasing the timer value of the failure determination timer Tm by 1, the process proceeds to step S2.
The program proceeds to step 2 to detect the load current value Im at that time. Thereafter, the process proceeds to step S23, where the difference Im-Io between the load current value Im and the load current initial value Io is set to the threshold value fcap1.
It is determined whether it is smaller than (the, ftl).
At this time, Im-Io is equal to the threshold value fcap1 (th
e, ftl) or more, the routine proceeds to step S24, where it is determined that fuel may leak from the filler cap, and the leak diagnosis is stopped. Thereafter, in step S25, the switching valve 15 is opened, the electric pump 20 is turned off, and the process is terminated.

On the other hand, in step S23, Im-I
When it is determined that o is smaller than the threshold value fcap1 (the, ftl), the process proceeds to step S26, where I
It is determined whether m-Io is equal to or greater than threshold value Is1.
If it is determined that Im-Io is equal to or larger than the threshold value Is1, the process proceeds to step S29, and there is no leak corresponding to a case where a hole having a diameter of 0.5 mm is present in the evaporative fuel supply system, and it is normal. Is determined, the switching valve 15 is opened in step S25, the electric pump 20 is turned off, and the process ends.

In step S26, Im-I
When it is determined that o is smaller than the threshold value Is1, the process proceeds to step S27, and it is determined whether the failure determination timer value Tm is equal to or greater than the threshold value T (3). At this time, if it is determined that the timer value Tm is smaller than the threshold value T (3), the process returns to step S21 and returns to step S21.
The processing after 21 is performed again. On the other hand, when it is determined in step S27 that the timer value Tm is equal to or greater than the threshold value T (3), the process proceeds to step S28, which corresponds to a case where the evaporative fuel supply system has a hole having a diameter of 0.5 mm. It is determined that there is a leak, the switching valve 15 is opened in step S25, the electric pump 20 is turned off, and the process ends.

The processing flow of the above fault diagnosis device will be described with reference to the time charts of FIGS. In each figure, the vertical axis represents the load current value Im of the electric pump 20, and the horizontal axis represents time Tm. In FIG. 6,
(A) shows a graph in the case where there is a relatively large leak in the evaporative fuel supply system corresponding to a leak when there is a hole of about 1.0 mm, and (b) shows a graph in the case where there is a hole of about 0.5 mm. 4 shows a graph in the case where a relatively small leak corresponding to the leak exists in the evaporative fuel supply system, and (c) shows a graph in the case where there is no leak in the evaporative fuel system. FIG. 3 shows a time chart when the vehicle inclination angle is 30 ° and the remaining amount of fuel in the fuel tank is 75%.

First, the graph (a) will be described.
After the processing of steps S1 to S6 in FIG. 2 is performed,
At a point P1 in FIG. 6, the switching valve 15 is opened, and the load current threshold value Iref of the electric pump 20 is detected (corresponding to step S7 in FIG. 2). Thereafter, at a point P2 in the drawing, the switching valve 15 is closed, and the load current initial value Io of the electric pump 20 is detected (corresponding to step S8 in FIG. 2).

Then, while increasing the timer value of the failure determination timer Tm (corresponding to steps S9 and S10 in FIG. 2), at point P3 in FIG.
When (1) is reached, the difference Im-Io between the load current value Im at that time and the load current initial value Io is a threshold value f1 (ft) for determining that a relatively large leak has occurred.
(I, Iref-Io) is determined (corresponding to step S12 in FIG. 2).

At this time, the diagnostic parameters Im-Io are:
Since it is smaller than the threshold value f1 (ftl, Iref-Io), the timer value of the failure determination timer value Tm is increased (corresponding to steps S13 and S14 in FIG. 2), and the timer value becomes T (2). At the point P4 in the figure, the diagnostic parameter Im-Io at that time is a threshold value f2 for determining that a leak corresponding to the case where a hole having a diameter of about 1.0 mm exists is present. (Ftl, I
ref-Io) is determined (see FIG. 2).
In step S16). At this time, the diagnostic parameter Im-Io is set to the threshold value f2 (ftl, Iref
-Io) or less, it is determined that there is a large leak in the evaporative fuel supply system, and the process ends (corresponding to steps S17 and S18 in FIG. 2).

Next, the graph (b) will be described.
Step S in FIG.
After the processes of 1 to S11 are performed, when the timer value of the failure determination timer Tm becomes T (1) at a point P5 in FIG. 6, the diagnostic parameter Im-Io at that time is relatively large. It is determined whether it is greater than f1 (ftl, Iref-Io), which is a threshold value for determining that a leak has occurred (corresponding to step S12 in FIG. 2).

At this time, similarly to the above-mentioned graph (a),
When the diagnostic parameter Im-Io is equal to the threshold value f1 (ftl,
Iref-Io) or less, so the failure determination timer value I
m by increasing the timer value (step S1 in FIG. 2).
3 and S14), when the timer value reaches T (2), at point P6 in the figure, the diagnostic parameter Im-Io at that time indicates that a hole having a diameter of about 1.0 mm exists. Is determined to be greater than f2 (ftl, Iref-Io), which is a threshold value for determining that a leak corresponding to (2) (corresponding to step S16 in FIG. 2). At this time, since the diagnostic parameter Im-Io is larger than the threshold value f2 (ftl, Iref-Io),
I which is a threshold value for stopping pressurization by the current pump 20
s1 and filler cap leakage prevention threshold value fcap1
(The, ftl) is calculated (corresponding to steps S19 and S20 in FIG. 3).

Then, the load current value Tm is detected while increasing the timer value of the failure determination timer value Tm (corresponding to steps S21 and S22 in FIG. 3), and the diagnostic parameter Im-Io is set to the filler cap leakage prevention threshold value. fcap
It is determined whether it is smaller than 1 (the, ftl) (corresponding to step S23 in FIG. 3). At this time, the diagnostic parameter Im-Io is set to the threshold value fcap1 (th
e, ftl), it is further determined whether or not the diagnostic parameter Im-Io is equal to or greater than the threshold Is1 (corresponding to step S26 in FIG. 3). At this time, since the diagnosis parameter Im-Io is smaller than the threshold value Is1, the timer value of the failure determination timer Tm further becomes T
(3) It is determined whether or not this is the case (corresponding to step S27 in FIG. 3).

Then, steps S21 to S21 in FIG.
Steps S23, S26 and S27 are repeated while increasing the timer value, and when the timer value reaches T (3), at point P7 in FIG.
It is determined that there is a leak corresponding to the case where there is a hole having a diameter of m, and the processing is terminated (steps S28 and S28 in FIG. 3).
25).

Next, the graph (c) will be described.
Similar to the graphs (a) and (b) described above, after the processes in steps S1 to S11 in FIG. 2 are performed, at a point P8 in FIG.
When (1) is reached, the diagnostic parameter Im at that time
It is determined whether or not −Io is greater than threshold value f1 (ftl, Iref−Io) (step S in FIG. 2).
12).

At this time, the diagnostic parameters Im-Io are:
Since it is larger than the threshold value f1 (ftl, Iref-Io), the threshold value Is1 is similar to the graph of FIG.
And the filler cap leakage prevention threshold value fcap1 (th
e, ftl) (step S19 in FIG. 3).
And S20), while detecting the load current value Im while increasing the timer value of the failure determination timer value Tm (corresponding to steps S21 and S22 in FIG. 3), and setting the diagnostic parameter Im-Io to the threshold value fcap1 (thee). , Ftl) is determined (corresponding to step S23 in FIG. 3). At this time, the diagnostic parameter Im-Io
Is smaller than the threshold value fcap1 (the, ftl), the diagnostic parameter Im-Io further decreases the threshold value Is-Io.
It is determined whether it is 1 or more (corresponding to step S26 in FIG. 3). At this time, when the diagnostic parameter Im-Io becomes the same value as the threshold value Is1 at a point P9 in FIG. 6, it is determined that there is no leak in the evaporative fuel supply system and the process ends (see FIG. 6). 3 corresponds to steps S29 and S25).

Next, taking the graph of FIG. 7C as an example,
The process of the failure determination under conditions other than the condition that the vehicle inclination angle is 30 ° and the fuel remaining amount is 75% will also be described. First, when the vehicle is not inclined, the electric pump 2 is driven until the load current value Im reaches the threshold value Is1.
When the pressure is increased to 0 and the threshold value Is1 is reached, it is determined that there is no leak and the process is terminated (Case).
2).

In the case where the vehicle is inclined, first, when the inclination of the vehicle is 30 ° and the remaining amount of fuel in the fuel tank 2 is 75% under the same conditions as described above, as described above. When the load current value Im reaches the threshold value Is1, it is determined that there is no leak, and the process is terminated (Case 2). When the inclination of the vehicle is 30 ° and the fuel remaining amount in the fuel tank 2 is 85%, the load current I
Since m reaches the filler cap leakage prevention threshold value fcap1 (the, ftl) before m reaches the threshold value Is1, the process is interrupted at that time (Case 1) to prevent fuel leakage from the filler cap.

The threshold value Iref, which is the load current value of the electric pump 20 when the air is pumped from the electric pump 20 to the reference orifice 16, is larger than that in the normal state due to, for example, foreign matter clogging the reference orifice 16. The value may be Iref '. At this time, the threshold value I
s1 becomes Is1 'corresponding to the threshold value Iref',
For example, this threshold value Is1 'is determined when the vehicle inclination angle is 30.
° and threshold value fcap1 when the remaining fuel amount is 75%
The value is larger than (the, ftl).

As described above, when the threshold value Iref becomes large and becomes Iref ', even if the vehicle inclination angle is constant as described below, the leakage occurs in accordance with the remaining amount of fuel in the fuel tank 2. Diagnosis processing is different. That is, when the remaining amount of fuel is 85%, the load current value Im reaches the filler cap leakage prevention threshold value fcap1 (the, ftl) before reaching the threshold value Is1 '. Is interrupted (Case 1). Next, when the remaining fuel amount is 75%, the load current value Im reaches the threshold value fcap1 (the, ftl) before reaching the threshold value Is1 ', similarly to the case where the remaining fuel amount is 85%.
At that time, the processing is interrupted (Case 3). When the remaining amount of fuel is 65%, the threshold value Is1 'is smaller than the threshold value fcap1 (the, ftl). Therefore, when the load current value Im reaches the threshold value Is1', A normal determination is made that there is no leak, and the process ends (Case 4).

As described above, according to the configuration of the present invention, the prohibition condition that the vehicle inclination angle the becomes equal to or greater than the predetermined vehicle inclination angle such that the oil level of the fuel in the fuel tank 2 reaches the vicinity of the filler cap 3 is set. When the prohibition condition is detected by the detection, the pressurization of the evaporative fuel supply system is prohibited.
Thus, even if the filler cap 3 is loose or the seal member between the filler port and the filler port is deteriorated, it is possible to prevent the fuel from leaking from the filler port.

Further, a reference orifice 16 is provided, air is pumped from the electric pump 20 to the reference orifice 16, and the load current Iref of the electric pump 20 at that time is set as a threshold value. It is possible to effectively detect the hole of the fuel vapor supply system corresponding to the diameter.

(Embodiment 2) FIGS. 4 and 5 show Embodiment 2 of the present invention (in the following embodiments, FIGS.
In the first embodiment, the prohibition condition for prohibiting the diagnosis by the diagnosis unit is when the inclination angle of the vehicle is equal to or more than a predetermined value. However, this prohibition condition is changed.

That is, in this embodiment, the prohibition condition is:
It is assumed that the fuel level in the fuel tank 2 has exceeded a predetermined value. As shown in FIG. 1, an oil level sensor 23 for detecting a fuel level is provided in a filler port of the fuel tank 2 near the filler cap 3. The signal detected by the oil level sensor 23 is transmitted to the control unit 8
Output to

Then, in this embodiment, after the vehicle state is detected in step S1 in FIG. 2, the process proceeds to step S2 'in FIG. In this step S2 ', the oil level sensor 23 detects the fuel level ol in the fuel filler port of the fuel tank 2.
v is detected, and the process proceeds to step S3 '.

At step S3 ', the fuel level ol
It is determined whether or not v is smaller than a predetermined value. And
When the fuel level olv is equal to or higher than the predetermined value, the diagnosis prohibiting unit prohibits the leak diagnosis by the diagnosis unit and ends the process. When the fuel level is lower than the predetermined value, the process proceeds to step S4 in FIG. The same processing is continued.

Further, in the present embodiment, after step S19 in FIG. 3, the process proceeds to step S21 'in FIG. 5, the timer value of the failure determination timer Tm is increased by 1, and the process proceeds to step S22'. In step S22 ', the fuel level olv in the fuel filler port of the fuel tank 2 at that time is detected by the oil level sensor 23, and the process proceeds to step S23'. In this step S23 ', the fuel level olv
Is smaller than a predetermined value. If the fuel level olv is equal to or higher than the predetermined value, the process proceeds to step S in FIG.
Proceeding to step S24, the process terminates the process by ending the leak diagnosis by the diagnostic means on the assumption that fuel may leak from the filler cap 3, and if it is smaller than the predetermined value, the process proceeds to step S26 in FIG. The same processing as in 1 is continued.

The same effect as in the first embodiment can be obtained by configuring the failure diagnosis apparatus by setting the prohibition conditions in this manner.

(Embodiment 3) FIGS. 8 and 9 show Embodiment 3 of the present invention, in which the prohibition conditions of Embodiments 1 and 2 are changed. That is, in the present embodiment, the prohibition condition is that the pressure in the fuel tank 2 becomes equal to or higher than a predetermined value. As shown in FIG. 1, a pressure sensor 24 for detecting the pressure in the fuel tank 2 is provided in the fuel tank 2. The signal detected by the pressure sensor 24 is output to the control unit 8.

In this embodiment, the second embodiment is used.
8, after the vehicle state is detected in step S1 in FIG. 2, the process proceeds to step S2 ″ in FIG. 8. In this step S2 ″, the pressure P in the fuel tank 2 is detected by the pressure sensor 24.
t is detected, the process proceeds to step S3 ″, and it is determined whether or not the pressure Pt is smaller than a predetermined value.
If t is equal to or more than the predetermined value, the diagnosis prohibiting unit prohibits the leak diagnosis by the diagnosis unit and ends the process. If it is smaller than the predetermined value, the process proceeds to step S4 in FIG. The same processing is continued.

Further, in the present embodiment, after step S19 in FIG. 3, the process proceeds to step S21 "in FIG. 9, the timer value of the failure determination timer Tm is increased by 1, and the process proceeds to step S22". In step S22 ", the pressure Pt in the fuel tank 2 at that time is detected by the pressure sensor 24, and the flow proceeds to step S23". This step S2
At 3 ", it is determined whether or not the pressure Pt is smaller than a predetermined value.
In step S24, it is determined that there is a possibility that fuel may leak from the filler cap 3, and the leak diagnosis by the diagnostic unit is stopped to terminate the processing. On the other hand, if the value is smaller than the predetermined value, the flow proceeds to step S26 in FIG. The same processing as in the first and second embodiments is continued.

The same effect as in the first and second embodiments can be obtained by configuring the failure diagnosis apparatus by setting the prohibition conditions in this manner.

In each of the above embodiments, the diagnostic parameter is the current value of the electric pump 20. However, the diagnostic parameter may be at least one of the current value or the rotation speed of the electric pump 20. That is, the diagnostic parameter may be the rotation speed of the electric pump 20 and the electric pump 2
Both the current value of 0 and the rotation speed may be used. The diagnostic parameter may be the pressure in the fuel tank. By doing so, similarly to the above embodiments, a failure diagnosis device that diagnoses whether or not there is a leak in the evaporative fuel supply system can be effectively embodied.

The present invention is not limited to these, and other parameters that change depending on whether or not the fuel vapor leaks from the fuel vapor system may be used as diagnostic parameters.

[0067]

As described above, according to the first aspect of the present invention, when a predetermined diagnostic condition is satisfied, the evaporative fuel supply system from the fuel tank to the purge valve provided between the fuel tank and the internal combustion engine is provided. Pressurizing means for pressurizing the evaporative fuel supply system, and when the evaporative fuel supply system is pressurized by the pressurizing means, the abnormality of the evaporative fuel supply system is determined based on a diagnostic parameter which changes depending on whether or not the evaporative fuel leaks from the evaporative fuel supply system. Diagnostic means for diagnosing the condition; detecting means for detecting a predetermined prohibition condition in which the oil level of the fuel tank in the fuel tank is closer to the filler cap of the fuel tank than normal; By providing a diagnostic prohibiting unit that prohibits the diagnosis by the diagnostic unit when detected, even if the filler cap is loose or the seal member between the filler port is deteriorated, To prevent it being raised in the oil level of fuel reaches Irakyappu to the vicinity, it is possible to prevent leakage of fuel from the fuel supply port.

According to the second aspect of the present invention, the above-mentioned prohibition condition is set when the inclination angle of the vehicle becomes a predetermined value or more.
According to the third aspect of the present invention, the prohibition condition is that the pressure in the fuel tank becomes equal to or higher than a predetermined value. According to the invention of claim 4, the prohibition condition is that the fuel level in the fuel tank becomes equal to or higher than a predetermined value.
According to the inventions of claims 2 to 4, desirable prohibition conditions can be embodied.

According to the fifth aspect of the present invention, a reference orifice having a reference diameter is provided between the evaporative fuel supply system and the pressurizing means. By comparing with a reference parameter obtained by pressurizing the system leading to, the abnormality of the evaporative fuel supply system is diagnosed, so that the hole of the evaporative fuel supply system corresponding to the reference diameter of the reference orifice can be effectively used. It becomes possible to detect.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a failure diagnosis device for an evaporative fuel supply device according to a first embodiment.

FIG. 2 is a flowchart illustrating a leak diagnosis process according to the first embodiment.

FIG. 3 is a flowchart illustrating a leak diagnosis process according to the first embodiment.

FIG. 4 is a time chart illustrating a relationship between a time at the time of leak diagnosis and a load current value.

FIG. 5 is a diagram corresponding to FIG. 4, showing a relationship between a time at the time of leak diagnosis and a load current value.

FIG. 6 is a flowchart illustrating a leak diagnosis process according to the second embodiment.

FIG. 7 is a flowchart illustrating a leak diagnosis process according to the second embodiment.

FIG. 8 is a diagram showing a leak diagnosis process according to the third embodiment;
FIG.

FIG. 9 is a diagram showing a leak diagnosis process according to the third embodiment;
FIG.

[Explanation of symbols]

2 Fuel tank (evaporated fuel supply system) 5 Purge valve (evaporated fuel supply system) 6 Evaporated fuel introduction passage (evaporated fuel supply system) 7 Purge passage (evaporated fuel supply system) 8 Control unit (diagnosis means, detection means, prohibition of diagnosis) Means) 16 reference orifice 20 electric pump (pressurizing means, diagnostic means) 21 tilt angle sensor (detecting means) 22 remaining amount sensor (detecting means) Is1 Threshold for stopping pressurization (reference parameter) Im current of electric pump Value Im-Io Diagnosis parameter the The inclination angle of the vehicle Pt The pressure in the fuel tank olv The fuel level in the fuel tank

 ──────────────────────────────────────────────────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 BA32 DA07 EA32 EA40 EA53 EA55 FA00 FA04 FA23 FA31 FA39 FA40 GA09 GA26

Claims (7)

[Claims] A pressurizing means for pressurizing an evaporative fuel supply system from a fuel tank to a purge valve provided between the fuel tank and the internal combustion engine when a predetermined diagnostic condition is satisfied; When the fuel supply system is pressurized,
Diagnosing means for diagnosing an abnormal state of the fuel vapor supply system based on a diagnostic parameter which varies depending on whether or not the fuel vapor is leaked from the fuel vapor supply system; and Detecting means for detecting a predetermined prohibition condition that is close to the filler cap of the tank; and diagnosis prohibition means for prohibiting the diagnosis by the diagnosis means when the prohibition condition is detected by the detection means. Diagnostic device for the fuel vapor treatment device. 2. The failure diagnosis device for an evaporative fuel treatment device according to claim 1, wherein the prohibition condition is when the inclination angle of the vehicle becomes a predetermined value or more. . 3. The failure diagnosis device for an evaporative fuel treatment device according to claim 1, wherein the prohibition condition is when the pressure in the fuel tank becomes equal to or higher than a predetermined value. apparatus. 4. The failure diagnosis apparatus for an evaporative fuel treatment apparatus according to claim 1, wherein the prohibition condition is when the fuel level in the fuel tank has exceeded a predetermined value. Diagnostic device. 5. The failure diagnosis apparatus for an evaporative fuel processing apparatus according to claim 1, further comprising a reference orifice having a reference diameter between the evaporative fuel supply system and the pressurizing means, wherein the diagnostic means performs a diagnosis. The system is configured to compare a parameter with a reference parameter obtained by pressurizing a system from the pressurizing unit to the reference orifice by the pressurizing unit to diagnose an abnormality of the evaporative fuel supply system. Diagnosis device for evaporative fuel processing equipment. 6. The failure diagnosis device for an evaporative fuel treatment device according to claim 1, wherein the pressurizing means is an electric pump, and the diagnosis parameter is at least one of a current value and a rotation speed of the electric pump. A fault diagnosis device for an evaporative fuel treatment device, characterized in that: 7. The failure diagnosis device for an evaporative fuel treatment device according to claim 1, wherein the diagnosis parameter is a pressure in a fuel tank.