JP2003222057A - Failure diagnostics system for fuel vapor processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make diagnoses more frequently and enhance diagnostic accuracy, while avoiding an erroneous diagnosis made as a result of a sloshing. <P>SOLUTION: The fuel vapor processing apparatus provided for an engine 1 of a vehicle traps vapor produced in a fuel tank 2 using a canister 13, purges a fuel component of the vapor to an intake passageway 6 through a purge line 17, and adjusts a purge flow rate using a purge control valve 24. An atmospheric air control valve 18 is used to regulate the amount of atmospheric air introduced to the canister 13. When a predetermined period of time elapses after the engine is stopped, an electronic control unit (ECU) 30 for the failure diagnostics system closes the purge control valve 24 and the atmospheric air control valve 18 to totally close a processing path between the fuel tank 2 and the purge control valve 24. The ECU 30 thereafter opens a negative pressure control valve 27 and a selector valve 28 to reduce pressure in the processing path by means of a holding negative pressure of a negative pressure tank 25. After the pressure is reduced, the ECU 30 diagnoses airtightness of the processing path based on a behavior of the pressure detected with a pressure sensor 29. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporation system in which evaporated fuel generated in a fuel tank is collected by a canister, and the fuel component in the collected evaporated fuel is purged into an intake passage of an engine for processing. The present invention relates to a fuel processor. More specifically, the present invention relates to a failure diagnosis device that diagnoses a failure related to the airtightness of the evaporated fuel processing device.

[0002]

2. Description of the Related Art Conventionally, as one of the devices mounted on a vehicle, there is known an evaporated fuel processing device for processing evaporated fuel (vapor) generated in a fuel tank without releasing it to the atmosphere. This device has a canister that collects vapor, and once the vapor is adsorbed by the adsorbent inside the canister,
Using the negative pressure generated in the intake passage during engine operation, the fuel components (hydrocarbons (HC), etc.) in the vapor collected in the canister are purged into the intake passage through the purge passage and burned in the engine. It is designed to be processed by being provided.

By the way, in this type of processing apparatus, a failure may occur for some reason, such as a leak hole in the flow path including the canister from the fuel tank to the intake passage, or a defective seal at the pipe joint. In that case, the airtightness of the flow path becomes poor. In this case, the vapor generated in the fuel tank cannot be properly treated.

To cope with such a failure, it is necessary to diagnose the failure early. Some technologies for this kind of failure diagnosis have already been proposed, but JP-A-11-31
Japanese Patent No. 1153 discloses an example of this type of diagnostic device.

The basic idea of this kind of failure diagnosis is that the flow path of the processing device is a closed space, and the closed space is in a state where there is a relative pressure difference with respect to atmospheric pressure, and then the pressure change is measured. By doing so, the presence or absence of a leak or the like is diagnosed. For example, a pressure difference with respect to the atmospheric pressure is obtained in the flow passage by reducing the pressure of the flow passage by using a negative pressure generated in the intake passage before forming the closed space in the flow passage.

When a vehicle equipped with an engine and an evaporated fuel processing device is assumed, it depends on the driving conditions and driving method of the vehicle, that is, traveling on a bad road, sudden acceleration, sudden deceleration, or lane change. Depending on the operating method described above, a phenomenon (hereinafter referred to as “sloshing”) such as rocking / jumping of the fuel liquid level occurs in the fuel tank, which causes rapid vaporization and increases the pressure in the flow path of the processing device. It is known. At this time, if the inside of the flow path is decompressed to form a closed space and a leak or the like is diagnosed, an erroneous diagnosis may be performed. In order to avoid this kind of erroneous diagnosis, it is desirable to depressurize the flow path after the vehicle is stopped.

Therefore, it is conceivable that when the vehicle is stopped and the engine is in an idle operation state, the negative pressure generated in the intake passage is guided to the passage of the processing device to reduce the pressure of the passage. However, at this time, the air mixed with vapor existing in the flow path may flow into the intake passage, and the air-fuel ratio of the engine may be disturbed.

Further, a certain amount of time is required to complete the depressurization of the flow path of the processing apparatus, and a certain amount of time is also required to measure the pressure change while maintaining the depressurized state. Therefore, the leak diagnosis cannot be performed unless the vehicle is stopped for at least a time period including both of them, and if the stop time of the vehicle is short, the opportunity to perform the leak diagnosis is lost.

Therefore, focusing on this problem, in the diagnostic device disclosed in Japanese Patent Laid-Open No. 11-311153, the flow from the fuel tank to the purge control valve in the middle of the purge passage while the vehicle is traveling or the engine is in the non-idle operation state. By completing the depressurization of the road, avoiding the disturbance of the air-fuel ratio due to the depressurization and immediately holding the flow path in the depressurized state when the vehicle is in the stopped state or a state close to the stopped state. The leak diagnosis is performed by measuring the pressure change. As a result, it is possible to increase the chance of diagnosis while avoiding erroneous diagnosis due to sloshing.

[0010]

However, in the diagnosis device of the above-mentioned prior art, since the pressure of the flow passage is reduced by simply introducing the negative pressure generated in the intake passage into the flow passage of the processing device, It is difficult to improve the accuracy of the diagnosis because the pressure change of 1 is relatively small and the S / N for judging normality / abnormality tends to be small.

The present invention has been made in view of the above circumstances, and an object thereof is to increase the chances of diagnosis while avoiding erroneous diagnosis due to sloshing, and at the same time, to improve the accuracy of diagnosis. It is an object of the present invention to provide a failure diagnosis device for an evaporated fuel processing device that is enabled.

[0012]

In order to achieve the above object, the invention according to claim 1 is provided corresponding to an engine mounted on a vehicle, and a canister captures evaporated fuel generated in a fuel tank. And a purge control valve that controls the fuel component in the collected evaporated fuel to the intake passage of the engine and controls the purge flow rate, and the introduction of the atmosphere to the canister. A failure diagnosis device for an evaporated fuel processing device, comprising an atmosphere control valve, which detects a processing flow path including a canister between a fuel tank and a purge control valve, and a pressure in the processing flow path. Pressure detecting means for, and a pressure accumulator for holding the negative pressure generated in the intake passage during engine operation,
The negative pressure control valve for controlling the introduction of the negative pressure from the pressure accumulator to the processing flow path, and when the engine stops for a predetermined time, the purge control valve and the atmospheric control valve are closed to close the processing flow path. After sealing, the negative pressure control valve is controlled to open and the negative pressure is introduced from the pressure accumulator into the processing flow passage to reduce the pressure inside the processing flow passage. The purpose is to provide a diagnostic means for diagnosing the airtightness of the processing channel based on the behavior of the pressure applied.

According to the structure of the above invention, the purge control valve and the atmospheric control valve are opened when the engine is operating, so that the negative pressure generated in the intake passage acts on the processing flow passage to collect the evaporated fuel collected in the canister. The fuel component therein is purged into the intake passage and processed. Further, the negative pressure generated in the intake passage is held in the pressure accumulator. After that, when the engine is stopped, when the predetermined time has elapsed after the engine was stopped, the pressure reduction control means controls the purge control valve and the atmospheric control valve to be closed to seal the processing flow path, and then the negative pressure The negative pressure held in the pressure accumulator is introduced into the processing flow passage by controlling the opening of the pressure control valve, and the inside of the processing flow passage is depressurized. At this time, the pressure of the processing channel is detected by the pressure detecting means, and the airtightness of the processing channel is diagnosed by the diagnosing means based on the behavior of the detected pressure after the pressure is reduced. Therefore, after the vehicle stops together with the engine for a predetermined time, the behavior of the pressure in the sealed processing channel is detected, so that the sloshing does not occur in the fuel tank and the pressure in the processing channel becomes stable. The condition is used for diagnosis. Further, since the negative pressure introduced to reduce the pressure of the closed processing flow path is the negative pressure that is temporarily held in the pressure accumulator, the pressure difference with respect to the atmospheric pressure is higher than the negative pressure generated in the intake passage. Becomes large,
The S / N for diagnosis becomes large.

In order to achieve the above object, the invention described in claim 2 is, in the invention described in claim 1, characterized in that the canister is arranged in a fuel tank.

According to the structure of the invention described above, in addition to the operation of the invention described in claim 1, it is not necessary to provide a dedicated installation space for the canister in the vehicle.

In order to achieve the above object, the invention according to claim 3 is the invention according to claim 1 or 2, wherein the vehicle includes an electric motor in addition to the engine, and the engine or the electric motor is selectively used. And a vehicle speed detecting means for detecting the vehicle speed of the hybrid vehicle, and a diagnostic permitting means for permitting diagnosis by the diagnostic means when the detected vehicle speed becomes zero. The purpose is to have and.

In the hybrid vehicle having the structure of the above invention, the engine may be stopped and the vehicle may be driven only by the electric motor, and only the engine is mounted as an opportunity to introduce the negative pressure generated in the intake passage into the processing flow path. Less than vehicles.
However, according to the configuration of the above invention, since the negative pressure generated in the intake passage is retained in the pressure accumulator, if the negative pressure is retained in the pressure accumulator during operation of the engine, it can be appropriately extracted for diagnosis. It becomes possible to use. Therefore, when the vehicle speed detected by the vehicle speed detecting means becomes zero and the hybrid vehicle is stopped, the diagnosis by the diagnosing means is permitted by the diagnosing permitting means. Therefore, in addition to the function of the invention according to claim 1 or 2, Even in a hybrid vehicle, it is possible to perform a failure diagnosis of the evaporated fuel processing device when the engine is stopped.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] A first embodiment of the failure diagnosis apparatus for an evaporated fuel processing apparatus according to the present invention will be described below.
Embodiments will be described in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of the evaporated fuel processing apparatus and its failure diagnosis apparatus of the present embodiment. A gasoline engine system mounted on an automobile as a vehicle includes an engine 1 and a fuel tank 2 for containing fuel supplied to the engine 1. The fuel discharged from the fuel pump 3 built in the fuel tank 2 is distributed and supplied to each injector 4 provided corresponding to a plurality of cylinders of the engine 1 through a fuel line 5 or the like. The operation of each injector 4 causes the intake passage 6 from each injector 4 to move.
Fuel is injected into. An air cleaner 7 is provided in the intake passage 6.
Purified air is introduced through. This mixture of air and injected fuel is supplied to the combustion chamber 8 of each cylinder of the engine 1. Exhaust gas produced after combustion in each combustion chamber 8 of the engine 1 is exhausted to the outside through an exhaust passage 9. With the combustion of the air-fuel mixture in each combustion chamber 8, the piston 10 operates and the crankshaft 11 rotates, so that a driving force is obtained in the engine 1. This driving force is transmitted to driving wheels (both not shown) via a transmission or the like, whereby the automobile runs.

The evaporated fuel processing apparatus of this embodiment is for collecting and processing evaporated fuel (vapor) generated in the fuel tank 2 without releasing it into the atmosphere.
This evaporative fuel treatment apparatus includes a canister 13 for collecting vapor generated in the fuel tank 2 through a vapor line 12. The canister 13 contains an adsorbent 14 made of activated carbon.

The canister 13 has a first atmospheric valve 15 and a second atmospheric valve 16. First and second atmospheric valve 1
5 and 16 are constituted by diaphragm type check valves each having a spring. When the internal pressure of the canister 13 is lower than the atmospheric pressure, the first atmospheric valve 15 opens against the biasing force of the spring, allows the atmospheric air (atmospheric pressure) to be introduced into the canister 13, and gas in the opposite direction. Stop the flow of. The tip of an air pipe 17 extending from the atmosphere valve 15 is connected to the air cleaner 7. In the middle of the air pipe 17, for opening and closing the flow path of the pipe 17, that is,
Atmosphere control valve 1 of the present invention comprising an electromagnetically controlled solenoid valve for controlling the introduction of atmosphere to the canister 13.
8 are provided.

The second atmosphere valve 16 opens against the biasing force of the spring when the internal pressure of the canister 13 is higher than the atmospheric pressure, and the second atmospheric valve 16 is opened from the canister 13 to the outlet port 19.
Allowing the gas (internal pressure) to flow to the cylinder and stopping the flow of gas in the opposite direction.

The vapor control valve 20 provided in the canister 13 is for adjusting the vapor flowing from the fuel tank 2 to the canister 13 through the vapor line 12. The vapor control valve 20 is composed of a diaphragm type check valve having a spring. Vapor control valve 20
Is the internal pressure (hereinafter referred to as “tank internal pressure”) Pt on the fuel tank 2 side including the vapor line 12, and the canister 1.
Internal pressure on side 3 (hereinafter referred to as "canister internal pressure") Pc
It is opened by operating a diaphragm-type valve element based on the pressure difference between and. The opening of the vapor control valve 20 allows the vapor to flow from the fuel tank 2 into the canister 13. That is, in the vapor control valve 20, the internal pressure Pc of the canister becomes almost the same as the atmospheric pressure, and the internal pressure P
When c is larger than the tank internal pressure Pt, it opens to allow the vapor to flow into the canister 13. On the contrary, the vapor control valve 20 allows the gas flow from the canister 13 to the fuel tank 2 when the canister internal pressure Pc is higher than the tank internal pressure Pt.

Purge line 2 extending from canister 13
1 communicates with a surge tank 23 located downstream of the throttle valve 22 in the intake passage 6. Canister 13
Collects only the fuel component in the vapor introduced from the fuel tank 2, and discharges only the gas containing no fuel component from the outlet port 19 to the outside through the second atmosphere valve 16. During operation of the engine 1, the negative pressure generated in the intake passage 6 acts on the purge line 21, and the fuel component collected in the canister 13 is purged into the intake passage 6 through the line 21 and processed. The purge control valve 24 provided in the purge line 21 is for adjusting the purge flow rate in the purge line 21. Purge control valve 2
Reference numeral 4 denotes an electromagnetic valve that receives an electric signal to operate the valve body 24a, and the opening degree of the valve body 24a is duty-controlled. In this evaporation processing device, the vapor line 12 and the canister 13 are provided between the fuel tank 2 and the purge control valve 24.
The flow path including the purge line 21 and the purge line 21 corresponds to the processing flow path of the present invention.

A failure diagnosis device for diagnosing a failure related to the airtightness of the fuel vapor processing apparatus is a negative pressure tank 25,
A check valve 26, a negative pressure control valve 27, a switching valve 28, a pressure sensor 29, and an electronic control unit (ECU) 30 are provided. The negative pressure tank 25 is for introducing and holding the negative pressure generated in the intake passage 6 during operation of the engine 1 through the negative pressure introducing passage 31, and corresponds to the pressure accumulator of the present invention. One end of the negative pressure introducing passage 26 is connected to the surge tank 23. The check valve 26 is provided in the middle of the negative pressure introducing passage 31 and stops the flow of gas from the negative pressure tank 25 to the surge tank 23. The switching valve 28 is provided in the middle of the communication passage 32 that communicates between the fuel tank 2 and the canister 13. The pressure sensor 29 is provided corresponding to the communication passage 32 on the fuel tank 2 side of the switching valve 28, and detects the pressure applied to the communication passage 32. The pressure sensor 29 corresponds to the pressure detecting means of the present invention. The negative pressure control valve 27 is provided in the middle of the negative pressure derivation path 33 that leads from the negative pressure tank 25 to the communication path 32. The negative pressure control valve 33 connects the negative pressure tank 25 to the communication passage 32.
It is for controlling the introduction of negative pressure to the.

In the above structure, the negative pressure tank is closed by closing the atmospheric control valve 18 and the purge control valve 24 and opening the negative pressure control valve 27 and the switching valve 28 while the negative pressure is held in the negative pressure tank 25. The negative pressure held at 25 causes the vapor line 12 from the fuel tank 2 to the purge control valve 24,
It is introduced into the processing flow path including the canister 13, the purge line 17, and the like.

In addition to the above, the engine 1 is provided with various sensors (not shown) for detecting various parameters relating to its operating state. For example, an intake pressure sensor for detecting the pressure of the air taken into the intake passage 6 (intake pressure), a throttle sensor for detecting the opening of the throttle valve 22 (throttle opening), cooling water for the engine 1. A water temperature sensor for detecting the temperature (cooling water temperature), a rotation speed sensor for detecting the rotation speed of the crankshaft 11 (engine rotation speed), and an oxygen concentration in the exhaust gas flowing through the exhaust passage 9. An oxygen sensor or the like is provided.

The ECU 30 corresponds to the depressurization control means and the diagnosis means of the present invention. The ECU 30 executes engine control such as fuel injection control in order to drive the engine 1 based on the signals output from the various sensors. For example, the ECU 30 controls each injector 4 in order to execute the fuel injection control. Also, the ECU 30
Executes purge control of the evaporated fuel processing device. For example, the ECU 30 controls the purge control valve 24 based on a required drive duty value in order to purge the fuel component in an amount suitable for the operation of the engine 1.

In addition, the ECU 30 executes control of failure diagnosis related to the airtightness of the evaporated fuel processing apparatus. ECU30
Is the atmospheric control valve 18, the purge control valve 24, and the negative pressure control valve 2 as necessary, based on detection signals from various sensors.
7 and the switching valve 28 are controlled, and the detection signal from the pressure sensor 29 is input. The ECU 30 diagnoses a failure related to the airtightness of the processing flow path between the fuel tank 2 and the purge control valve 24 based on the input detection value of the pressure sensor 29. This failure includes a failure related to the airtightness of the fuel tank 2, a failure related to the airtightness of the canister 13, a failure related to the airtightness of the pipe joints of the vapor line 12 and the purge line 21, and the like.

Warning lamp 3 provided in the driver's seat of the automobile
Reference numeral 4 operates to notify the driver of the diagnosis result or the like related to the above-mentioned failure. The ECU 30 turns on or blinks the warning lamp 34 when it is diagnosed as a failure, and turns off the warning lamp 34 in other cases.

As is well known, the ECU 30 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a backup RAM, an external input circuit and an external output circuit. The ECU 30
A CPU, a ROM, a RAM, a backup RAM, and an external input circuit and an external output circuit are connected by a bus to form a logical operation circuit. The ROM stores in advance a predetermined control program relating to engine control, purge control, failure diagnosis control, and the like. The RAM temporarily stores the calculation result of the CPU. The backup RAM stores previously stored data. Here, the backup RAM is
The diagnostic result regarding the failure will be saved as diagnostic data. The CPU executes each of the injectors 4, the atmospheric control valve 18, the purge control valve 24, in order to execute the engine control, the fuel purge control, the failure diagnosis control, and the like based on the detection signals of various sensors input via the input circuit. The negative pressure control valve 27, the switching valve 28, the warning lamp 34, etc. are controlled respectively.

In addition, the external input circuit of the ECU 30 includes
An ignition switch (IGSW) 35 and a soak timer 36 are connected. The ignition switch 35 is operated to be turned on and off to start and stop the engine 1, allows the ECU 30 to be turned on when the engine 1 is turned on, and shuts off power supply to the ECU 30 when turned off. The soak timer 36 starts counting when the ignition switch 35 is turned off,
This is for allowing the ECU 30 to temporarily turn on the power when the engine 1 is left for a predetermined time after being stopped.

Next, the processing contents of the failure diagnosis control executed by the ECU 30 will be described. FIG. 2 shows a flowchart regarding the failure diagnosis routine. The ECU 30 executes this routine once when the ignition switch (IGSW) 35 turns off.
When the soak timer 36 is set to F and the temporary power-on of the ECU 30 is permitted, the soak timer 36 is started.

First, in step 100, the ECU 30
It is determined whether or not the ignition switch (IGSW) 35 is turned off. If the determination result is negative, the ECU 30 returns the process to step 100, assuming that the engine 1 is not stopped. If the determination result is affirmative, it is determined that the engine 1 is stopped and the vehicle is stopped, and the ECU 30 shifts the processing to step 110.

At step 110, the ECU 30 determines whether or not a predetermined time has elapsed after the stop. The predetermined time period is a time period in which the fuel tank 2 and the like are cooled to some extent after the engine 1 is stopped and the tank internal pressure Pt is stabilized, and, for example, about 1 hour is a standard. This predetermined time is
This corresponds to the value measured by the soak timer 36.
If the determination result is negative, the ECU 30 returns the process to step 100, and if the determination result is affirmative, the ECU 30 shifts the process to step 120.

At step 120, the ECU 30 reads the value of the tank internal pressure Pt detected by the pressure sensor 29.
Due to this reading, the tank internal pressure Pt immediately after the elapse of a predetermined time
Gives the value of.

Next, at step 130, the ECU 30
The atmosphere control valve 18 and the purge control valve 24 are controlled to be closed. As a result, the vapor line 12, the canister 13, and the purge line 17 from the fuel tank 2 to the purge control valve 24.
The processing flow path including the above is sealed.

Next, at step 140, the ECU 30
The negative pressure control valve 27 and the switching valve 28 are controlled to open. As a result, the negative pressure held in the negative pressure tank 25 is introduced into the sealed processing channel, and the inside of the processing channel is depressurized.

Next, at step 150, the ECU 30
The value of the internal pressure (flow path internal pressure) Pa of the processing flow path after depressurization is read.

Then, in step 160, the ECU 30
Determines whether or not the value of the read channel internal pressure Pa is equal to or less than the value of the read tank internal pressure Pt minus a predetermined value p1. Here, for example, a value of about “2660 kPa” can be applied to the “predetermined value”. If the result of this determination is negative, the ECU 30 returns the processing to step 100, assuming that the state of the flow passage internal pressure Pa is insufficient for performing the failure diagnosis. If the result of this determination is affirmative, the ECU 30 determines that the state of the flow passage internal pressure Pa is necessary and sufficient for performing the failure diagnosis, and the ECU 30 shifts the processing to step 170.

At step 170, the ECU 30 closes the negative pressure control valve 27. As a result, the communication from the negative pressure tank 25 to the processing flow path is cut off, and the introduction of negative pressure into the processing flow path is stopped.

Next, at step 180, the ECU 30
The value of the flow path internal pressure Pa is read again.

Next, at step 190, the ECU 30
The value of the internal pressure change ΔPa of the flow path internal pressure Pa is calculated. This internal pressure change ΔPa is calculated by obtaining the difference between the value of the flow passage internal pressure Pa read this time and the value of the flow passage internal pressure Pa read last time.

Then, in step 200, the ECU 30
Determines whether the value of the internal pressure change ΔPa is smaller than the normality determination value. As this "normality determination value", for example, "-1"
A value of about 330 to −2260 kPa ”can be applied. If this determination is positive, the pressure change Δ
Since Pa is small, the ECU 30 determines that the airtightness of the processing channel is normal, and the ECU 30 shifts the processing to step 210.

In step 210, the ECU 30 stores a normal code indicating that the processing flow path is normal in the backup RAM. This normal code is read out when necessary when the engine 1 is inspected.

Further, in step 220, the ECU 30 turns off the warning lamp 34, thereby ending the series of failure diagnosis. The off state of the warning lamp 34 is maintained even when the engine 1 is subsequently started.

On the other hand, if the result of the determination in step 200 is negative, then in step 230, the ECU 30 determines whether or not the value of the internal pressure change ΔPa is greater than or equal to the abnormality determination value.
As this “abnormality judgment value”, for example, “2128 to 226
A value of about 1 kPa can be applied. If the determination result is negative, the pressure change ΔPa is not large enough to determine the abnormality, and therefore the ECU 30 returns the process to step 100. On the other hand, if this determination result is affirmative, the ECU 30 determines that the airtightness of the processing flow path is abnormal because the pressure change ΔPa is large, and the ECU 30 shifts the processing to step 240.

At step 240, the ECU 30 stores an abnormality code indicating that the processing flow path is abnormal in the backup RAM. This abnormality code is also read out when necessary when the engine 1 is inspected.

Further, in step 250, the ECU 30 turns on the warning lamp 34 in order to inform the driver that there is a failure in the evaporated fuel processing apparatus, and with this, a series of failure diagnosis is completed. The lighting state of the warning lamp 34 is maintained even when the engine 1 is subsequently started.

The fault diagnosis control described above is performed by the soak timer 36.
As a result, the process is completed while the power supply to the ECU 30 is being performed, and thereafter, the power supply to the ECU 30 is cut off again.

According to the fuel vapor processing apparatus of this embodiment described above, the purge control valve 2 is operated when the engine 1 is operating.
4 and the atmosphere control valve 18 are opened, the intake passage 6
The negative pressure generated in 1) acts on the processing flow path of the evaporated fuel processing apparatus, and the fuel component in the evaporated fuel once collected in the canister 13 is purged into the intake passage 6 and processed.

According to the failure diagnosis device of this embodiment,
The negative pressure generated in the intake passage 6 is temporarily held in the negative pressure tank 25. After that, when the engine 1 is stopped, the purge control valve 24 and the atmosphere control valve 18 are controlled to be closed by the ECU 30 and the processing flow path is sealed when a predetermined time has passed after the stop. After that, the negative pressure control valve 27 and the switching valve 28
Is controlled to be opened by the ECU 30 and the negative pressure held in the negative pressure tank 25 is introduced into the processing flow passage, and the inside of the processing flow passage is depressurized. That is, the fuel tank 2 and the vapor line 1
2. The inside of the canister 13 and the purge line 17 is depressurized for failure diagnosis. At this time, the pressure of the processing flow path (flow path internal pressure Pa) is detected by the pressure sensor 29, and the airtightness of the processing flow path is based on the value of the pressure change ΔPa indicating the behavior of the internal flow path pressure Pa after depressurization. Is diagnosed by the ECU 30.

Therefore, after the vehicle stops together with the engine 1 and a predetermined time has passed, the behavior of the flow passage internal pressure Pa of the sealed processing flow passage is detected by the pressure change ΔPa.
Sloshing does not occur in the fuel tank 2, and the flow passage internal pressure Pa is used for failure diagnosis of the processing flow passage in a state where the flow passage internal pressure Pa is stable. Therefore, it is possible to increase the chances of failure diagnosis while avoiding erroneous diagnosis due to sloshing.

According to the failure diagnosis apparatus of this embodiment,
Since the negative pressure introduced to reduce the pressure of the closed processing flow path is the negative pressure temporarily held in the negative pressure tank 25, the negative pressure generated in the intake passage 6 is higher than the atmospheric pressure. The difference is large, and S / N for failure diagnosis
Grows larger. Therefore, the accuracy of failure diagnosis can be improved.

According to the failure diagnosis apparatus of this embodiment,
When it is diagnosed that the evaporated fuel processing device has a failure related to airtightness, the warning lamp 34 provided in the driver's seat is turned on. Therefore, the driver can immediately know the failure that has occurred in the fuel vapor processing apparatus, and can take the action against the failure early. Therefore, it is possible to prevent the situation in which vapor is released from the evaporated fuel processing device into the atmosphere from being left carelessly.

According to the failure diagnosis apparatus of this embodiment,
When it is diagnosed that the vaporized fuel processing device has a failure related to airtightness, an abnormality code indicating this is stored in the backup RAM of the ECU 30. Therefore, when the vehicle is inspected, the operator can check the history regarding the above failure by reading the abnormality code in the backup RAM. Therefore, it is possible to reliably detect a failure of the evaporated fuel processing device and deal with the failure.

[Second Embodiment] Next, a second embodiment embodying a failure diagnosing apparatus for an evaporated fuel processing apparatus according to the present invention will be described with reference to the drawings. In each of the following embodiments including the present embodiment, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted, and different points will be mainly described. And

FIG. 3 is a schematic diagram showing the structural features of the engine system, the evaporated fuel processing apparatus and its failure diagnosis apparatus according to this embodiment. In this embodiment,
The canister 13 is arranged and fixed in the fuel tank 2, and the configuration is different from that of the first embodiment in that respect.
The other structure is basically the same as that of the first embodiment.

Therefore, in this embodiment, since the canister 13 is of the in-tank type arranged in the fuel tank 2, it is not necessary to provide a dedicated installation space for the canister 13 in the automobile. Therefore, the evaporated fuel processing device can be made more compact than that of the in-tank type device, and the mountability of the device in a vehicle can be improved.

Further, since the canister 13 is of the in-tank type, the canister internal pressure Pc and the tank internal pressure Pt become equal, and there is no need to distinguish them. For this reason,
The communication passage 32 shown in FIG. 1 and the switching valve 28 associated therewith can be omitted, and in this sense, the failure diagnosis device can be made more compact than that without the in-tank type. It is possible to improve the mountability in a car.

Other functions in this embodiment
The effect is basically the same as that of the evaporated fuel processing apparatus and its failure diagnosis apparatus of the first embodiment.

[Third Embodiment] Next, a third embodiment of the invention will be described with reference to the drawings.

This embodiment differs from the above embodiments in that the evaporated fuel processing device and its failure diagnosis device are mounted as an automobile on a "hybrid vehicle". Here, as shown in FIG. 4, the hybrid vehicle 41 includes an electric motor (motor) 42 in addition to the engine 1, and selectively uses the engine 1 or the motor 42 to drive wheels 43.
Is to drive. Engine 1 and motor 42
Are connected to the drive wheels 43 via a gear unit 44 containing a transmission, a gear train and the like. The evaporated fuel processing device and its failure diagnosis device according to this embodiment are mounted on the hybrid vehicle 41 in association with the engine 1 of the hybrid vehicle 41.

FIG. 5 shows a schematic structure of the evaporated fuel processing apparatus and its failure diagnosis apparatus of this embodiment. The failure diagnosis device of this embodiment has a vehicle speed sensor 45 for detecting the vehicle speed of an automobile as one of the constituent elements. Also, ECU
The reference numeral 30 allows the failure diagnosis control described with reference to FIG. 2 when the detected vehicle speed becomes zero. In this embodiment, the vehicle speed sensor 45 corresponds to the vehicle speed detecting means of the present invention, and the ECU 30 corresponds to the diagnosis permitting means of the present invention. In this respect, the present embodiment is different in configuration from the failure diagnosis device of each of the above embodiments.

In the hybrid vehicle 41 having the structure of this embodiment, the engine 1 may be stopped and the vehicle may be driven only by the motor 42, and the negative pressure generated in the intake passage 6 may be removed from the fuel tank 2 by the purge control valve. Up to 24, vapor line 12, canister 13 and purge line 17
The opportunity to introduce into the processing flow path constituted by including is smaller than that in a vehicle equipped with only the engine 1.

However, in this embodiment, the intake passage 6
Since the negative pressure generated in the negative pressure tank 25 is held in the negative pressure tank 25, if the negative pressure generated in the intake passage 6 during operation of the engine 1 is held in the negative pressure tank 25, it can be appropriately extracted and used for diagnosis. It becomes possible to do. Therefore, the vehicle speed sensor 4
When the vehicle speed detected at 5 is zero, that is, when the hybrid vehicle 41 is stopped, the ECU 30 allows the failure diagnosis control as described in FIG. By taking out the negative pressure from the negative pressure tank 25 at the time of stopping, it becomes possible to introduce the negative pressure into the processing flow path between the fuel tank 2 and the purge control valve 24, and the failure diagnosis of the evaporated fuel processing apparatus can be performed. It becomes possible to do. Therefore, the hybrid vehicle 4
Also in No. 1, it is possible to increase the number of diagnosis opportunities while avoiding erroneous diagnosis due to sloshing in the evaporated fuel processing device.

Other functions in this embodiment
The effect is basically the same as that of the evaporated fuel processing apparatus and its failure diagnosis apparatus of the first embodiment.

The present invention is not limited to the above-mentioned embodiments, but can be carried out as follows within the scope of the invention.

For example, in the third embodiment, the first
Although the evaporated fuel processing device and the failure diagnosis device thereof according to the embodiment are applied to the hybrid vehicle 41, the evaporated fuel processing device and the failure diagnosis device according to the second embodiment may be applied to the hybrid vehicle 41. In this case, the hybrid vehicle 41 can also obtain the action and effect peculiar to the second embodiment.

[0070]

According to the invention described in claim 1, when the engine is stopped and a predetermined time has passed, the purge control valve and the atmospheric control valve are closed to seal the processing flow path, and then the negative pressure is applied. The control valve is opened to introduce a negative pressure from the pressure accumulator into the processing flow passage to reduce the pressure inside the processing flow passage, and based on the behavior of the pressure detected by the pressure detection means after the pressure reduction, the processing flow passage Since the airtightness is diagnosed, it is possible to increase the chances of diagnosis while avoiding erroneous diagnosis due to sloshing, and at the same time, to improve the accuracy of diagnosis.

According to the invention of claim 2, claim 1
In the invention described in (1), since the canister is arranged in the fuel tank, in addition to the effect of the invention described in (1), compared with the case where the canister is not arranged in the fuel tank, the evaporated fuel processing device and its failure diagnosis It is advantageous that the device can be made more compact and the mountability of the device in a vehicle can be improved.

According to the invention of claim 3, claim 1
In the invention according to claim 2 or 3, the failure diagnosis device is applied to a hybrid vehicle so that the diagnosis is allowed when the vehicle speed becomes zero. Therefore, the effect of the invention according to claim 1 or 2 is achieved in a hybrid vehicle. There is also an effect that can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a failure diagnosis device of an evaporated fuel processing device according to a first embodiment.

FIG. 2 is a flowchart showing the processing contents of failure diagnosis control.

FIG. 3 is a schematic diagram showing a structural feature of a failure diagnosis device or the like of an evaporated fuel processing device according to a second embodiment.

FIG. 4 is a schematic diagram showing a hybrid vehicle according to a third embodiment.

FIG. 5 is a schematic configuration diagram showing a failure diagnosis device of the evaporated fuel processing device.

[Explanation of symbols]

1 Engine 2 Fuel Tank 6 Intake Passage 12 Vapor Line 13 Canister 18 Atmosphere Control Valve 21 Purge Line 24 Purge Control Valve 25 Negative Pressure Tank (Accumulator) 27 Negative Pressure Control Valve 29 Pressure Sensor (Pressure Detection Means) 30 ECU (Decompression Control) Means, diagnostic means, diagnostic permitting means) 41 hybrid vehicle 42 motor (electric motor) 43 drive wheels 45 vehicle speed sensor (vehicle speed detecting means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 45/00 345 G01M 15/00 Z // G01M 15/00 B60K 15/02 LF term (reference) 2G087 AA19 BB39 CC11 EE26 3D038 CA25 CB01 CC02 CC05 CC07 CD17 CD18 3G044 AA10 BA22 CA02 DA07 EA53 EA55 EA57 FA02 FA32 FA39 3G084 AA00 BA27 DA27 EA07 FA00 FA05 FA36 3G093 AA07 AA16 BA24 BA34 CA11 DB05 DA02 DA02 DA02 DA02 DA02 DA02

Claims (3)

[Claims] 1. A canister provided corresponding to an engine mounted on a vehicle collects evaporated fuel generated in a fuel tank by a canister, and the fuel component in the collected evaporated fuel is introduced into an intake passage of the engine. A failure diagnosis device for an evaporated fuel processing device, comprising a purge control valve that is controlled for purging and adjusting the purge flow rate, and an atmosphere control valve for controlling the introduction of atmosphere to the canister. A processing flow path including the canister between the fuel tank and the purge control valve, pressure detection means for detecting a pressure in the processing flow path, and the intake passage during operation of the engine. Accumulator for holding the negative pressure generated in, the negative pressure control valve for controlling the introduction of negative pressure from the accumulator to the processing flow path, where the engine is stopped When the time has elapsed, the purge control valve and the atmosphere control valve are closed and the processing flow passage is sealed, and then the negative pressure control valve is opened to negative pressure from the pressure accumulator to the processing flow passage. By introducing a pressure reducing control means for reducing the pressure in the processing flow path, and diagnosing the airtightness of the processing flow path based on the behavior of the pressure detected by the pressure detection means after the pressure reduction. A failure diagnosis device for an evaporated fuel processing device, comprising: 2. The failure diagnosis device for an evaporated fuel processing apparatus according to claim 1, wherein the canister is arranged in the fuel tank. 3. The vehicle is a hybrid vehicle that includes an electric motor in addition to the engine, and selectively uses the engine or the electric motor to drive driving wheels, and detects the vehicle speed of the hybrid vehicle. 3. The evaporated fuel according to claim 1 or 2, further comprising: vehicle speed detection means for detecting the vehicle speed; and diagnostic permission means for permitting the diagnosis by the diagnostic means when the detected vehicle speed becomes zero. Failure diagnosis device for processing equipment.