JP2616620B2 - Abnormality detector for evaporative purge system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detection device for an evaporative purge system, and more particularly to an abnormality detection device for an evaporative purge system configured to detect an abnormality by detecting a pressure in a passage of evaporated fuel.

[0002]

2. Description of the Related Art Generally, fuel evaporated in a fuel tank is
It is configured to be adsorbed by a canister filled with activated carbon or the like so that evaporated fuel (hereinafter, also simply referred to as fuel) is not released to the atmosphere. Further, since the capacity of the canister is limited and the amount of fuel that can be adsorbed is limited, the fuel adsorbed by the canister is purged to the intake pipe of the engine and burned for the purpose of preventing overflow of the canister and the like. There is an evaporation purge system.

[0003] In this evaporative purge system, when a failure such as damage to a vapor passage or disconnection of a pipe occurs for some reason, there is a possibility that the canister overflows or fuel is released to the atmosphere. For this reason, an evaporative purge system provided with an abnormality detection device for self-diagnosing a failure has been proposed.

[0004] Conventionally, as an abnormality detecting device of this evaporation purge system, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. 2-130255. The abnormality detection device disclosed in the publication provides a pressure sensor between the canister in the purge passage and the purge control valve, and detects an abnormality in the evaporative purge system based on a pressure at the time of purging and a pressure change before and after opening and closing of the purge control valve. It was configured to detect.

[0005]

However, in the above-described conventional apparatus, since the pressure sensor is provided in the purge passage, if an abnormality occurs in the vapor passage from the fuel tank to the canister, this is detected. There was a problem that it was not possible.

Further, when an abnormality is to be detected in the vapor passage, it is necessary to provide a pressure sensor not only in the purge passage but also in the vapor passage, which leads to an increase in the number of parts and a complicated structure. There has been a problem that the structure of the abnormality detecting means for performing abnormality detection based on the signal of the sensor becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide an abnormality detection device for an evaporative purge system capable of detecting an abnormality in both a purge passage and a vapor passage with one pressure sensor. Aim.

[0008]

In order to solve the above-mentioned problems, according to the present invention, there is provided a vapor passage through which a fuel tank communicates with a canister to introduce the evaporated fuel generated in the fuel tank into the canister, and a fuel adsorbed by the canister. An evaporative purge system provided with a purge passage for purging the fuel into an intake system of the engine, the evaporative purge system abnormality detecting device for detecting an abnormality of the evaporative purge system by detecting a pressure in the passage. It communicated with the passage and the purge passage, provided the pressure sensor in one of the vapor passage or the purge passage, and the pressure sensor during the purge in response to engine parameters
An abnormality detecting means for determining that an abnormality has occurred in the evaporative purge system when the changing predetermined pressure is not detected is provided.

[0009]

According to the abnormality detecting device having the above-described structure, the vapor passage and the purge passage are communicated with each other, so that the abnormality of the entire evaporative purge system including the vapor passage can be detected by one pressure sensor.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an abnormality detection apparatus 10 for an evaporative purge system according to a first embodiment of the present invention.

In FIG. 1, reference numeral 11 denotes a canister, which is filled with an adsorbent 11a such as activated carbon. The canister 11 is connected to a fuel tank 13 by a vapor passage 12. Therefore, the fuel vapor generated in the fuel tank 13 is introduced into the canister 11 through the vapor passage 12, and is adsorbed by the adsorbent 11a, so that the canister 1
It is held within 1. A purge passage 15 is provided between the canister 11 and an intake pipe 14 of an engine (not shown).
Is provided. The purge passage 15 is configured to communicate with the intake pipe 14 downstream thereof when a throttle valve 16 disposed in the intake pipe 14 is opened by a predetermined degree or more. The evaporative purge system 20 includes the canister 11, the vapor passage 12, the fuel tank 13, and the intake pipe 1.
4, a purge passage 15 and the like.

The abnormality detecting device 10 according to the present invention is characterized in that the vapor passage 12 and the purge passage 15 are communicated with each other, and a pressure sensor 17 is disposed in the vapor passage 12. For this reason, a communication passage 18 that connects the vapor passage 12 and the purge passage 15 is provided above the canister 11, and a throttle 19 is provided in the communication passage 18.
Are arranged. Further, the pressure sensor 17 is connected to an engine control unit (ECU) 21.

The evaporative purge system 2 having the above configuration
The operation of 0 will be described below.

In the above evaporative purge system 20,
When fuel vapor (vapor) is generated in the fuel tank 13, the fuel vapor passes through the vapor passage 12 and reaches the communication passage 18.
Since the communication passage 18 is provided with the throttle 19, the fluid resistance is lower when flowing into the canister 11 than when passing through the communication passage 18, so that most of the evaporated fuel flows into the canister 11 and is adsorbed by the adsorbent 11a. Is done.

Further, purging of the fuel adsorbed by the canister 11 is performed as follows. When a throttle valve 16 (which is interlocked with a throttle sensor (not shown)) provided in the intake pipe 14 is opened, the air introduced into the intake pipe 14 flows in the direction of the arrow in FIG.
Becomes negative pressure. The negative pressure applied to the purge passage 15 is applied to the canister 11 and also to the vapor passage 12 via the throttle 19. However, as described above, since the fluid resistance of the communication passage 18 is larger than that of the canister 11 due to the presence of the throttle 19, the fuel adsorbed from the canister 11 passes through the purge passage 15 and flows through the intake pipe 14.
Are purged. By the above series of operations, the evaporative purge system 20 adsorbs the evaporated fuel generated in the fuel tank 13 by the canister 11 and purges the fuel adsorbed by the canister 11 into the intake pipe 14. Therefore, even if the communication path 18 is provided, the basic function of the evaporation purge system 20 is not affected at all.

Here, the reason why the throttle 19 (orifice) is provided in the communication passage 18 will be described. If there is no orifice, the value will be small if there is a leak, but negative pressure will act on the whole system. However, if an orifice is provided, the diameter of the orifice is temporarily smaller than the diameter of the leak hole,
And leak holes also upstream Ri by an orifice (fuel tank side)
In this case, since the passage resistance of the orifice is larger than the passage resistance of the leak hole, no negative pressure is applied to the upstream side (fuel tank side) of the orifice.

Therefore, by providing the orifice and providing the pressure sensor upstream of the orifice (on the side of the fuel tank), it is possible to further improve the accuracy of abnormality detection. For this purpose, a throttle 19 (orifice) is provided in the communication passage 18. That is, by the large become the airflow resistance of the orifice, the orifice upstream Ri substantially Do a static system, a large difference in the how the application of negative pressure in the absence of a leak is present occurs.

Next, the operation of the abnormality detecting device 10 will be described.

The abnormality detection processing performed by the abnormality detection device 10 includes:
This is executed as a program process of the ECU 21, and the abnormality detecting means is constituted by software based on this program. This ECU 21 is a microcomputer,
Central processing circuit (CPU), read-only memory (R
OM), a random access memory (RAM), and the like. The ECU 21 is connected to various sensors such as a throttle sensor, a water temperature sensor, and an air flow meter. Based on signals supplied from these sensors, the ECU 21 performs various controls such as fuel injection control, ignition timing control, and the like. And an abnormality detection process which is a main part of the present invention.

FIG. 2 is a flowchart showing the abnormality detection processing executed by the ECU 21. The abnormality detection processing shown in the figure is an interruption routine interrupted by a signal supplied from, for example, a throttle sensor.

When the processing shown in FIG.
In step 100 (hereinafter, step is referred to as S), it is determined whether or not the throttle opening is an opening suitable for abnormality detection based on a throttle opening signal from a throttle sensor. Then, in S100, if the throttle opening is not an opening suitable for abnormality detection, the processing is terminated. If the opening is suitable for abnormality detection, the processing proceeds to S101.

In step S101, a pressure signal supplied from the pressure sensor 17 is fetched. In subsequent S102, S101
It is determined whether or not the pressure in the vapor passage 12 has reached a predetermined pressure on the basis of the pressure signal taken in at step (1).

Now, assuming that the evaporative purge system 20 is normal and the pipe is not disconnected, the negative pressure applied to the purge passage 15 by opening the throttle valve 16 is reduced to the communication passage 18. , Throttle 19 is also applied to the vapor passage 12. However, when an abnormality occurs in the evaporative purge system 20 and disconnection of the piping or the like occurs, the air flows into the passages 12 and 15 or the passage is clogged at the abnormality occurrence portion, and the pressure sensor The pressure detected at 17 is the engine parameter
It does not reach the predetermined pressure determined by the throttle opening, one of the data . Therefore, abnormality of the evaporative purge system 20 can be detected by detecting the pressure in the passages 12 and 15 .

Further, since the vapor passage 12 and the purge passage 15 are communicated with each other, even if an abnormality occurs in any one of the passages 12, 15 or the canister 11, the fuel tank 13,
The effect appears both on each of the passages 12,15. Therefore, the pressure sensor 17 for performing abnormality detection is connected to the vapor passage 12.
Alternatively, it is only necessary to dispose one in one of the purge passages 15, whereby it is possible to detect an abnormality of the evaporation purge system 20 as a whole. Therefore, the number of parts and the structure of the abnormality detection device 10 can be reduced and the structure thereof can be simplified. Further, the abnormality detection program of the ECU 21 may be configured to perform abnormality detection based on a signal from one pressure sensor 17. Can be simplified.

Based on the above-described abnormality detection principle, S102
If it is determined that the pressure in the vapor passage 12 has reached the predetermined pressure, the ECU 21 determines that no abnormality has occurred in the evaporative purge system 20, and ends the processing. On the other hand, if it is determined in S102 that the pressure in the vapor passage 12 has not reached the predetermined pressure, the process proceeds to S103, in which the ECU 21 turns on the warning lamp 22, and the driver has an abnormality in the evaporation purge system 20. Let them know you are doing it. As described above, according to the abnormality detection device 10 of the present invention, it is possible to reliably detect the abnormality of the evaporation purge system 20 with a device having a simple configuration.

FIGS. 3 and 4 show a canister 30 applied to an abnormality detecting apparatus according to a second embodiment of the present invention. Since the abnormality detection device according to the second embodiment is the same as the abnormality detection device 10 according to the first embodiment shown in FIG. 1 except for the configuration of the canister 30, only the canister 30 is illustrated and described. .

In the abnormality detecting device 10 according to the first embodiment,
Although the vapor passage 12 and the purge passage 15 communicate with each other at a position outside the canister 11, the abnormality detection device according to the second embodiment is characterized in that the vapor passage 12 and the purge passage 15 communicate with each other inside the canister 30. It is assumed that.

FIG. 3 is an enlarged sectional view showing an upper portion of the canister 30, and FIG. 4 is an overall view of the canister 30. As shown in each figure, in the canister 30, a flow path 31 to which the vapor path 12 is connected at the upper part thereof is branched into two to form first and second branch paths 31a and 31b. Check balls 32a, 33a urged by coil springs 32b, 33b are disposed at the adsorbent side ends of the first and second branch paths 31a, 31b, respectively.
The check balls 32a, 33a and the coil springs 32b, 33b constitute check valves 32, 33.
The check valve 32 displaces the check ball 32a when the fuel vapor flowing from the fuel tank 13 is higher than a predetermined pressure, and the fuel vapor from the fuel tank 13 is supplied to the canister 1.
1 has a function of permitting the fluid to flow into the device 1. On the other hand, when the negative pressure in the fuel tank 13 becomes higher than a predetermined value, the check ball 33a is displaced and the check valve 33 is displaced.
1 has a function of allowing the fuel adsorbed to the fuel tank 1 to flow back to the fuel tank 13.

Also, formed on the upper part of the canister 11,
The check valve 3 is also provided in the flow path 34 to which the purge passage 15 is connected.
5 (consisting of a check ball 35a and a coil spring 35b) are provided.
This check valve 35 is used when the negative pressure in the
Is opened, and the fuel adsorbed in the canister 11 is purged to the suction pipe 14 via the purge passage 15.

A communication passage 36 is formed between the flow passage 31 connected to the vapor passage 12 and the flow passage 34 connected to the purge passage 15. This communication passage 3
A throttle 37 is formed at a predetermined position on the side of the flow path 31 of No. 6. Therefore, by using the canister 30, the same effect as that of the first embodiment can be realized, and
The piping structure in the upper part of the canister 30 can be simplified.

FIG. 5 shows an abnormality detecting device 40 according to a third embodiment of the present invention. In the figure, the same components as those of the abnormality detection device 10 shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

The abnormality detecting device 40 shown in FIG. 1 includes an inflow passage of the vapor passage 41 to the canister 11 and a purge passage 4.
The two outflow paths are shared by one common pipe 43. With this configuration, the piping structure can be further simplified.

FIG. 6 shows an abnormality detecting device 50 according to a fourth embodiment of the present invention. In the figure, the same components as those of the abnormality detection device 10 shown in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

In the abnormality detecting device 50, the vapor passage 51 and the purge passage 52 are independently connected to the canister 11, and a bypass passage 53 is provided between the vapor passage 51 and the purge passage 52. I have. In the bypass passage 53, a first solenoid valve 54 (hereinafter, referred to as VSV 54) that closes when power is not supplied and opens when power is supplied, and an orifice 55 that restricts the bypass passage 53 is provided. Have been. Further, a second solenoid valve 56 (hereinafter, referred to as a VSV 56) for controlling an evaporative purge (that is, controlling a purge amount of the evaporated fuel to the intake pipe 14) is provided in the purge passage 52.
Is provided. Each of the above VSVs 54, 5
Numerals 6 are configured such that their drive control is performed by the ECU 21.

At the connection position of the vapor passage 51 of the canister 11, a first check ball 57 which opens when the internal pressure of the fuel tank 13 becomes higher than a set positive pressure.
Is provided, and the second check ball 58 is provided which opens when the tank pressure exceeds a predetermined negative pressure (Note that the first and second check ball of the 5
7, 58 may be used as a check valve).

Accordingly, when a large amount of fuel vapor is generated in the fuel tank 13 and the pressure increases while the VSV 54 is closed, the first check ball 57 opens,
The evaporated fuel is introduced into the canister 11 through the vapor passage 51, and is adsorbed and held by activated carbon provided in the canister 11. On the other hand, when the internal pressure of the fuel tank 13 becomes equal to or more than the predetermined negative pressure, the second check ball 58 opens and the atmosphere is introduced into the fuel tank 13, thereby ensuring the durability of the fuel tank 13.

As described above, even if the bypass passage 53 is provided between the vapor passage 51 and the purge passage 52, the VSV 5
When the valve 4 is closed, the vapor passage 51 and the purge passage 52 are independent from each other without communication, and the evaporated fuel does not directly enter the purge passage 52 from the vapor passage 51.

As described above, the VSVs 54 and 56 are EC
U21, and the pressure sensor 17 is also connected to the ECU
21. The ECU 21 is connected to a water temperature sensor for detecting a cooling water temperature, an idle switch for detecting an idle state, an engine speed sensor for detecting an engine speed, and the like, in addition to the pressure sensor 17 and the VSVs 54 and 56. Are not shown.

Next, the abnormality detection operation executed by the ECU 21 will be described. FIG. 7 is a flowchart showing the abnormality detection processing executed by the ECU 21. This process is a routine process executed, for example, every 32 ms. Note that the second VSV 56 is always kept open by the ECU 21 during the abnormality detection processing operation of the evaporation purge system described below.

When the abnormality detection process shown in the figure is started, the ECU 21 first determines in S200 whether or not an evaporative purge condition is satisfied. Here, it is determined whether or not the evaporative purge condition is satisfied. The abnormality detection process executed in a later step is a process for checking whether or not the evaporative purge system operates normally.
Therefore, it is necessary to perform the operation in a state where the evaporation purge system can be operated. Note that specific evaporative purge conditions include that the water temperature is equal to or higher than a predetermined temperature, that an idle switch is OFF (that is, not in an idle state), that air-fuel ratio learning is stopped, and the like.

If it is determined in step S200 that the evaporative purge condition is not satisfied, the process proceeds to step S212, in which it is determined that the condition is not such that an abnormality can be detected, and the VSV 54 is closed to terminate the process.

On the other hand, if it is determined in S200 that the evaporative purge condition is satisfied, the process proceeds to S201, where it is determined whether abnormality detection has been performed in the past. Specifically, it is determined whether the processing end flag XOPE is set (XOPE = 1). The processing end flag XOPE is a flag set in S210 when abnormality detection of the evaporative purge system is performed in S208 described later. Therefore, by determining the state of the processing end flag XOPE, it can be determined whether or not abnormality detection has been performed in the past.

As described above, in S201, it is determined whether or not abnormality has been detected in the past because the cause of the abnormality in the evaporative purge system is mainly a crack in the pipe or disconnection of the pipe. This is because safety can be sufficiently ensured by performing the abnormality detection once.

Therefore, if XOPE = 1 is determined in S201 and it is determined that the abnormality of the evaporative purge system has already been detected in the past, the process proceeds to S212, closes the VSV 54, and ends the process.

On the other hand, if XOPE = 0 is determined in S201 and it is determined that no abnormality has been detected in the evaporation purge system in the past, the process proceeds to S202.

In S202, it is determined whether the abnormality detection condition is satisfied. Here, the state in which the abnormality detection condition is satisfied means, for example, a state in which the engine speed, the intake pipe negative pressure, and the like are within predetermined ranges. That is, when the engine speed, the intake pipe negative pressure, and the like greatly fluctuate beyond a predetermined range, accurate abnormality detection of the evaporative purge system may not be performed. Therefore, in the unstable state in which the engine speed, the intake pipe negative pressure, and the like greatly fluctuate, no abnormality is detected, and in this case, the process proceeds to S212, the VSV 54 is closed, and the process is terminated. .

On the other hand, if it is determined in S202 that the abnormality detection condition is satisfied, the process proceeds to S203, and it is determined whether the VSV 54 provided in the bypass passage 53 is open.

As described above, in order to simplify the structure of the abnormality detection device and to perform abnormality detection using one pressure sensor 17, it is necessary to connect the vapor passage 51 and the purge passage 52. Therefore, at the time of abnormality detection processing, V
SV54 needs to be opened. Therefore, in S203, V
If it is determined that the SV 54 is closed, the process proceeds to S20.
4, the VSV 54 is opened. When the VSV 54 is opened, a counter COUN described later will be described in S205.
TER is reset (COUNTER = 0), and the first routine ends.

On the other hand, in the second and subsequent routine processing, if it is determined in S203 that the VSV 54 is open, the processing proceeds to S206, where the counter COUNTER is incremented. In the following S207, it is determined whether or not the incremented counter COUNTER is equal to or greater than a predetermined value N. If a negative determination is made in S207, the process ends without executing S212. Accordingly, the VSV 54 maintains the valve open state even when a negative determination is made in S207.

In step S207, the counter COUNTER is set.
Is determined to be greater than or equal to the predetermined value N, the process proceeds to S208.
Proceeds, the pressure value P to supply from the pressure sensor 17 whether it is below a predetermined pressure value P _A is determined.

As described above, in steps S206 and S207, S is maintained until the counter COUNTER becomes a predetermined value N or more.
The reason why the abnormality detection in step 208 is not performed is as follows.
This is because the internal pressures of the vapor passage 51, the purge passage 52, and the bypass passage 53 are not equalized even if the VSV 54 is opened. Even if an abnormality is detected in the evaporative purge system in a state where the internal pressure is non-uniform, accurate abnormality detection may not be performed. Therefore, by performing the processes in S206 and S207, the configuration is such that the internal pressures of the vapor passage 51, the purge passage 52, and the bypass passage 53 are set to wait for a predetermined time N to equalize, so that accurate abnormality detection can be performed.

[0052] In the abnormality detection process of S208, the pressure value P to supply from the pressure sensor 17 is determined to be below a predetermined pressure value P _A, it is determined that the abnormality is not such as leakage in the evaporative emission control system, The process proceeds to S210 without performing the warning process of S209. On the other hand, it is determined that the pressure value P to supply from the pressure sensor 17 is determined to be above a predetermined pressure value P _A, abnormalities such as leakage somewhere constituting the evaporation purge system has occurred, S20
At 9, a warning lamp 22 is turned on to notify the driver of the occurrence of an abnormality.

When the abnormality detection processing in step S208 is completed, in step S210, a processing end flag XOPE, which is a flag that is set when abnormality detection of the evaporative purge system is performed, is set (XOPE = 1). The counter COUNTER is reset (CO
(UNTER = 0), the VSV 54 is closed in S212, and the process ends.

As is apparent from the above description of the operation, the abnormality detection device 50 according to the present embodiment opens the VSV 54 only when performing the abnormality detection processing, connects the vapor passage 51 and the purge passage 52, and detects the abnormality. At other times, the VSV 54 is closed to separate the vapor passage 51 and the purge passage 52.

Therefore, when an abnormality is detected, the vapor passage 51 and the purge passage 52 are communicated with each other, so that a single pressure sensor 17 can detect an abnormality in the entire evaporative purge system, thereby simplifying the configuration of the abnormality detection device 50. be able to.

When the abnormality is not detected, the vapor passage 51 and the purge passage 52 are separated from each other.
Is independent, the fuel vapor generated in the fuel tank 13 does not directly flow into the purge passage 52, and the pressure in the fuel tank 13 can be maintained at a predetermined pressure, so that excessive generation of the fuel vapor can be prevented.

Although not shown in FIG. 7, VS
V54 is configured to be opened when the engine stops. Therefore, when the engine is stopped, the fuel tank 1
The internal pressure of 3 becomes atmospheric pressure because it communicates with the atmosphere through the vapor passage 51, the bypass passage 53, the canister 11, and the atmosphere opening pipe 11b, and evaporates even if cracks or the like occur in the piping constituting the evaporation purge system. Atmospheric emissions of fuel can be minimized. Also, during engine operation (except during abnormality detection processing), the VSV 54 is closed, so that the internal pressure of the fuel tank 13 is maintained at a predetermined pressure.
As described above, the generation of fuel vapor can be suppressed.

The processing end flag XOPE described in S201 and S210 is configured to be reset (XOPE = 0) when the engine is stopped.

The orifice 5 is provided in the bypass passage 53.
5 is provided, even if the VSV 54 is opened,
The amount of evaporated fuel flowing into the purge passage 52 from the vapor passage 51 is kept to a minimum. Therefore, there is no possibility that so-called air-fuel ratio roughness occurs during the abnormality detection processing.

In the fourth embodiment, no check ball is provided at the position where the purge passage 52 of the canister 11 is connected. Therefore, a certain percentage of the negative pressure is
Are met and escaped. That is, only a negative pressure corresponding to the passage resistance of the canister 11 acts on the system. And the orifice 5
5 is provided, and only a smaller negative pressure acts on the upstream side of the orifice 55 (the fuel tank 13 side).

Accordingly, the negative pressure acting on the fuel tank 13 can be reduced as much as possible, so that the burden on the fuel tank 13 is not only reduced, but also the generation of fuel vapor due to the negative pressure acting on the fuel tank 13 is promoted. Can be suppressed. At this time, since the upstream side of the orifice 55 is considered to be a substantially static system, if there is a leak, no negative pressure is applied to this upstream side at all. Therefore, the configuration is such that abnormality detection can be performed even with a small negative pressure.

Further, in the fourth embodiment, a second VSV 56 is provided in the purge passage 52 so as to provide the intake pipe 14 for the fuel vapor.
Although the purge amount is controlled, the VSV may be provided in the purge passage to control the purge amount of the evaporative fuel to the intake pipe 14 in the other embodiments described above. Conversely, it is clear that the effects of the present invention can be exerted even if the second VSV 56 is removed from the purge passage 52 in the fourth embodiment.

[0063]

As described above, according to the present invention, since the vapor passage and the purge passage communicate with each other, it is possible to detect an abnormality of the entire evaporative purge system including the vapor passage with one pressure sensor. It has such features that the structure of the abnormality detection device can be simplified.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating abnormality detection processing executed by an ECU in the first embodiment.

FIG. 3 is an enlarged view showing an upper portion of a canister applied to a second embodiment of the present invention.

FIG. 4 is a view showing a canister applied to a second embodiment of the present invention.

FIG. 5 is a diagram for explaining a third embodiment of the present invention.

FIG. 6 is a diagram for explaining a fourth embodiment of the present invention.

FIG. 7 is a flowchart illustrating an abnormality detection process executed by an ECU in a fourth embodiment.

[Explanation of symbols]

 10, 40, 50 abnormality detecting device 11, 30 canister 12, 41, 51 vapor passage 13 fuel tank 14 intake pipe 15, 42, 52 purge passage 16 throttle valve 17 pressure sensor 18, 36 communication passage 19 throttle 20 evaporation purge system 22 Warning lamps 31, 34 Flow paths 32, 33, 35 Check valve 37 Restrictor 43 Common piping 53 Bypass passage 54 VSV 55 Orifice

Claims (1)

(57) [Claims] 1. A fuel supply system comprising: a vapor passage communicating a fuel tank with a canister; introducing a vaporized fuel generated in the fuel tank into the canister; and a purge passage purging fuel adsorbed by the canister into an intake system of the engine. An abnormality detection device for an evaporative purge system, which is provided in the evaporative purge system and detects an abnormality of the evaporative purge system by detecting a pressure in the passage, wherein the vapor passage and the purge passage are communicated with each other. It provided a pressure sensor on one of passage or the purge passage, and the pressure sensor is an engine during the purge parameter over
An abnormality detection device for an evaporative purge system, comprising: abnormality detection means for determining that an abnormality has occurred in the evaporative purge system when a predetermined pressure that changes in accordance with the pressure is not detected.