JP4538988B2 - Failure diagnosis device for evaporative fuel treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a failure diagnosis apparatus for diagnosing a failure of an evaporative fuel processing apparatus that burns fuel by discharging evaporated fuel generated in a fuel tank to an intake system during a predetermined operation of the engine. Belonging to.
[0002]
[Prior art]
In recent years, automobiles and the like equipped with an engine that uses liquid fuel such as gasoline as fuel are equipped with an evaporative fuel processing device that combusts evaporative fuel generated in a fuel tank. It is possible to respond to the prevention of the release of. The evaporative fuel processing device adsorbs and holds evaporative fuel generated in the fuel tank in a canister, and releases the adsorbed evaporative fuel from the canister under a predetermined operating state of the engine and releases it to the intake system of the engine. Accordingly, the fuel vapor generated in the fuel tank is combusted.
[0003]
Some of this type of evaporated fuel processing apparatus is provided with a failure diagnosis apparatus for diagnosing the presence or absence of leakage in the processing apparatus as disclosed in Japanese Patent Application Laid-Open No. 11-336620. The failure diagnosis apparatus uses a method of pressurizing a purge system from a fuel tank to a purge valve after engine stop to diagnose a leak. An electric pump supplies pressurized air via a reference orifice having a reference diameter. After setting the determination level based on the load current value of the electric pump when the purge system is supplied and pressurizing the purge system, the electric pump when the purge system is pressurized by bypassing the reference orifice by the electric pump By comparing the load current value of the pump with the determination level, the presence or absence of a leak in the purge system is diagnosed. That is, for example, if there is a leak amount larger than the leak amount when the hole corresponding to the reference orifice is generated, the load current value of the electric pump is reduced from the determination level due to the decrease in the pressurizing load, so the load current value is the determination level. When it is smaller, it is determined that there is a leak.
[0004]
[Problems to be solved by the invention]
By the way, in the above-described failure diagnosis apparatus, it is determined that there is no leak when the load current value is larger than the determination level. However, the filter inserted in the air introduction passage connected to the downstream side of the electric pump or the electric motor The load current value of the electric pump may become larger than the determination level also by refueling the fuel tank on the upstream side of the pump. In other words, if the filter is clogged, the amount of air supplied from the downstream side of the electric pump is regulated, and if there is refueling to the fuel tank, it is pressurized from the upstream side of the electric pump. In both cases, the load current value of the electric pump may be larger than the determination level. For this reason, when it is determined that the load current value of the electric pump is larger than the determination level, it cannot be determined whether the purge system is normal without leaks, or whether the filter is clogged or fueled. There is a bug.
[0005]
Therefore, in view of the above-described problems in the failure diagnosis apparatus for the evaporated fuel processing apparatus, the present invention provides an evaporative fuel with improved diagnosis accuracy of the presence or absence of a leak in the purge system by making it possible to diagnose a filter blockage failure in advance. It is an object of the present invention to provide a failure diagnosis device for a processing device.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is configured as follows.
[0007]
A first aspect of the present invention is a pressurizing means for pressurizing and supplying air introduced through a filter to a purge system of evaporated fuel from a fuel tank to a purge valve, the pressurizing means and the purge system A pressure passage configured by a first passage for supplying pressurized air to a reference orifice and a second passage for bypassing the orifice and supplying pressurized air to the purge system; Switching means for switching the first and second passages of the pressurizing passage, and when the predetermined diagnosis condition is satisfied, the switching means first shuts off the second passage and supplies pressurized air to the reference orifice of the first passage. After that, the pressurization control means for communicating the second passage and supplying the pressurized air to the purge system through the second passage, and the change in the parameter corresponding to the presence or absence of the leak in the purge system at that time Purge system leak The present invention relates to a failure diagnosing device for an evaporative fuel processing apparatus provided with a diagnostic means for diagnosing the presence or absence, and after the pressurized air is supplied to the reference orifice by the pressurizing means, the passage is switched and the pressurized air is supplied to the purge system A time measuring means for measuring a time until the parameter reaches a value when pressurized air is supplied to the reference orifice, and when the time measured by the time measuring means is a predetermined value or less, the filter And occlusion determination means for determining that is in the occlusion state.
[0008]
According to the present invention, whether or not the filter is closed based on the time until the parameter when the pressurized air is supplied to the purge system reaches the value when the pressurized air is supplied to the reference orifice. Therefore, for example, if a filter blockage failure is confirmed, it is possible to diagnose the presence or absence of a leak in the purge system after repairing this defect. In other words, in spite of the filter clogging failure, it is possible to avoid a misdiagnosis that the purge system is normal with no leak.
[0009]
Next, according to a second aspect of the present invention, in the failure diagnosis apparatus for an evaporated fuel processing apparatus according to the first aspect, the blockage determining means determines whether or not the filter is closed when the engine is stopped. And configured to When it is determined by the determination means that the filter is in a closed state, During the determination, the fuel tank It was conducted Whether or not After the decision A refueling determination means and a refueling determination means When refueling was done When it is determined, the blockage determination means Blockage determination cancellation means for canceling the determination that the filter is in the closed state and determining that the filter is normal And is provided.
[0010]
Lubrication is another factor that reduces the time required for the parameter when pressurized air is supplied to the purge system to reach the value when pressurized air is supplied to the reference orifice. If When it is determined by the blockage determination means that the filter is closed, Whether refueling was done or not By the lubrication judgment means Judged, When refueling was done When it is determined, the blockage determination means by the blockage determination means Canceled Therefore, it is possible to prevent the filter from being erroneously diagnosed as having a clogging fault.
[0011]
According to a third aspect of the present invention, in the failure diagnosis apparatus for an evaporative fuel processing apparatus according to the second aspect, the fuel supply determining means is provided between when the engine is stopped and when the engine is operated next. It is characterized in that it is determined whether refueling has been performed based on a change in the remaining amount of fuel.
[0012]
According to this invention, the fuel supply determination means determines whether or not fuel supply is being performed based on a change in the remaining amount of fuel between when the engine is stopped and when the engine is operated next. It is easy to determine whether or not is performed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0014]
As shown in FIG. 1, an evaporative fuel introduction passage 3 for collecting evaporative fuel generated in the fuel tank 1 and leading it to the canister 2 is connected to the upper part of the fuel tank 1 in which liquid fuel such as gasoline is stored. The purge passage 4 connected to the canister 2 on the upstream side is connected to an intake passage (not shown) via a purge valve 5 to constitute a purge system for evaporated fuel from the fuel tank 1 to the purge valve 5. Has been. The tip of the fuel supply pipe 1a extending obliquely upward from the side wall of the fuel tank 1 is closed by a filler cap 1b. Further, a remaining amount sensor 6 for measuring the remaining amount of liquid fuel is provided in the fuel tank 1. The purge system is provided with a diagnosis unit 7 for diagnosing a failure of the purge system.
[0015]
In the diagnostic unit 7, an air introduction passage 12 in which a filter 11 is interposed communicates with a first passage 15 and a second passage 16 via an electric pump 14 driven by a motor 13, and a third passage. 17 is also provided so as to communicate. The first to third passages 15 to 17 merge and are connected to the canister 2 via the fourth passage 18. The electric pump 14 pressurizes the air introduced through the filter 11 and the air introduction passage 12 and supplies the pressurized air to the purge system as indicated by a white arrow so as to pressurize the purge system. It has become.
[0016]
A reference orifice 19 having a diameter of 0.5 mm is interposed in the first passage 15, and a switching valve 20 is interposed in the junction of the first to third passages 15 to 17. The operation of the switching valve 20 causes the fourth passage 18 and the first to third passages 15 to 17 to be branched and connected. That is, the switching valve 20 shuts off the third passage 17 in the closed state shown in FIG. 1 and puts the first, second, and fourth passages 15, 16, and 18 into the communication state, while the open state shown in FIG. In this state, the second passage 16 is shut off, and the first, third, and fourth passages 15, 17, 18 are operated.
[0017]
The vehicle according to the present embodiment is provided with an electronic control type control unit 21, which outputs control signals to the purge valve 5, the motor 13, and the switching valve 20, as well as the remaining amount. A fuel remaining amount signal from the sensor 6 and a load current value signal of the electric pump 14 from the motor 13 are input.
[0018]
Next, an example of the control operation by the control unit 21 will be described with reference to the flowcharts shown in FIGS. The characteristic part of the failure diagnosis described below is that it is configured to be able to diagnose the presence or absence of a leak in the purge system after diagnosing the blockage state of the filter 11 in advance.
[0019]
That is, in step S1, the control unit 21 that has input an OFF signal of an ignition switch (not shown) detects the fuel remaining amount FTL in the fuel tank 1 based on the signal from the remaining amount sensor 6 in step S2, and step S3. Then, the remaining fuel amount FTLm at this time is stored.
[0020]
Next, in step S4, the vehicle state is detected, and in step S5, it is determined whether a leak diagnosis execution condition is satisfied. Here, the leak diagnosis execution condition is, for example, whether or not the engine is stopped, whether or not the outside air temperature is within a predetermined range, and whether or not the remaining fuel amount FTL in the fuel tank 1 is within the predetermined range. Whether the failure diagnosis device such as the electric pump 14 or the switching valve 20 is normal. If it is determined that the leak diagnosis execution condition is not satisfied, the diagnosis process is terminated. If it is determined that the execution condition is satisfied, the process proceeds to step S6.
[0021]
In step S6, the timer value of the failure determination timer Tm is reset and set to 0, and then in step S7, an operation signal is output to the motor 13 to turn on the electric pump 14.
[0022]
In step S8, the switching valve 20 is opened and the second passage 16 is shut off, and then the air introduced through the filter 11 is pressurized by the electric pump 14 and the reference orifice 19 provided in the first passage 15 is provided. And the load current threshold Iref of the electric pump 14 at that time is measured.
[0023]
Next, in step S9, the switching valve 20 is closed to allow the second passage 16 to communicate, and then the pressurized air is supplied to the purge system by the electric pump 14, and the load current of the electric pump 14 at that time is supplied. After detecting the initial value Io, in step S10, the load current value Im of the electric pump 14 corresponding to the timer value of the failure determination timer Tm is detected.
[0024]
In step S11, it is determined whether or not the detected load current value Im is smaller than the load current threshold Iref. If it is determined that the detected load current value Im is smaller than the load current threshold Iref, the timer value of the failure determination timer Tm is determined in step S12. It is determined whether or not it is equal to or greater than a first determination threshold value T (1) set in advance, and if it is determined that the value is smaller than the first determination threshold value T (1), the timer value is increased by 1 in step S13 and the process proceeds to step S10. Return.
[0025]
On the other hand, if it is determined in step S11 that the load current value Im is greater than or equal to the load current threshold value Iref, the process proceeds to step S14, and the timer value until the load current value Im by the failure determination timer Tm reaches the load current threshold value Iref is determined. Then, it is determined whether or not it is smaller than a preset filter blockage determination threshold value To.
[0026]
If it is determined in step S14 that the timer value is equal to or greater than the filter blockage determination threshold value To, this means that the filter 11 is normal, not a blockage failure, and the process returns to step S12. If it is determined that the filter 11 is small, this means that there is a possibility that the filter 11 has a clogging fault. Therefore, in step S15, the filter 11 is temporarily determined to have a clogging fault, and then switched in step S16. The valve 20 is changed from the closed state to the open state, and the electric pump 14 is turned off.
[0027]
Next, in step S17, the ignition switch is turned on. In step S18, the remaining fuel amount FTL is detected. In step S19, the remaining fuel amount FTL and the remaining fuel amount FTLm stored in step S3 are detected. It is determined whether or not the difference is smaller than a preset oil supply determination threshold value fkyu.
[0028]
If it is determined in step S19 that the difference between the fuel remaining amount FTL and the fuel remaining amount FTLm is equal to or greater than the fuel supply determination threshold fkyu, this means that fuel supply to the fuel tank 1 is performed during the determination of the closed state of the filter 11. In step S20, the filter 11 is temporarily determined to be a clogging fault, but is actually determined to be normal without a clogging fault, while the remaining fuel level FTL and the remaining fuel level FTLm are If it is determined that the difference is smaller than the fuel supply determination threshold fkyu, this means that fuel supply to the fuel tank 1 has not been performed during the determination of the closed state of the filter 11, and therefore the filter 11 is blocked in step S21. It is determined that there is a failure, and the diagnosis process is terminated together. If it is determined that the filter 11 has a blocking failure, the driver is informed of the failure by lighting the lamp or the like. Thereafter, the driver brings the vehicle into a repair shop, and the filter 11 is repaired.
[0029]
On the other hand, if it is determined in step S12 that the timer value of the failure determination timer Tm is greater than or equal to the first determination threshold value T (1), the load current value Im of the electric pump 14 at that time is detected in step S22. The diagnosis of the presence / absence of a leak in the purge system will be executed.
[0030]
That is, in step S23, the difference Im-Io between the load current value Im and the load current initial value Io becomes the fuel remaining amount FTL and the difference Iref-Io between the load current threshold Iref and the load current initial value Io. Based on this, it is determined whether or not it is larger than the large leak determination threshold f1 that determines that there is a relatively large leak. That is, the difference Im-Io is a leak diagnosis parameter, and the parameter Im-Io changes depending on the presence or absence of leak when the electric pump 14 pressurizes the purge system. For example, when there is a leak, the load of the electric pump 14 becomes smaller than when there is no leak, that is, the load current value Im becomes smaller, so the leak diagnosis parameter Im-Io changes. .
[0031]
If it is determined in step S23 that the leak diagnosis parameter Im-Io is equal to or smaller than the large leak determination threshold f1, whether or not the timer value of the failure determination timer Tm is greater than or equal to a preset second determination threshold T (2) in step S24. Determine whether or not. If it is determined that the timer value of the failure determination timer Tm is smaller than the second determination threshold value T (2), the timer value is increased by 1 in step S25, and the process returns to step S24 again, while the second determination threshold value T (2 If it is determined that the above is satisfied, the load current value Im of the electric pump 14 at that time is detected in step S26.
[0032]
Next, in step S27, the leak diagnosis parameter Im-Io is determined in advance based on the remaining fuel amount FTL and the difference Iref-Io between the load current threshold Iref and the load current initial value Io, and a relatively large leak ( For example, it is determined whether or not it is greater than a 1 mm diameter leak determination threshold value f <b> 2 that determines that there is a leak) corresponding to a case where there is a hole having a diameter of about 1 mm.
[0033]
If it is determined in step S27 that the leak diagnosis parameter Im-Io is equal to or less than the 1 mm diameter leak determination threshold f2, then in step S28, it is determined that there is a relatively large leak in the purge system, and then in step S29, the switching valve 20 Is changed from the closed state to the open state, and the electric pump 14 is turned off, and the diagnosis process is terminated.
[0034]
On the other hand, if it is determined in step S23 that the leak diagnosis parameter Im-Io is greater than the large leak determination threshold f1, it is determined in step S27 that the leak diagnosis parameter Im-Io is greater than the 1 mm diameter leak determination threshold f2. If so, the process proceeds to step S30.
[0035]
That is, in step S30, a pressurization stop threshold Is1, which is a threshold for canceling pressurization of the purge system by the electric pump 14, is calculated by multiplying the load current threshold Iref by a predetermined value.
[0036]
Next, in step S31, a filler cap leakage prevention threshold fcap1 determined according to the fuel remaining amount FTL in the fuel tank 1 is set. The filler cap leak prevention threshold fcap1 is a limit value that may cause liquid fuel to leak from the filler cap 1b.
[0037]
In step S32, the timer value of the failure determination timer Tm is incremented by 1. In step S33, the load current value Im of the electric pump 14 at that time is detected.
[0038]
Next, in step S34, it is determined whether or not the leak diagnosis parameter Im-Io is smaller than the filler cap leak prevention threshold fcap1, and if it is determined that the leak cap is less than or equal to the filler cap leak prevention threshold fcap1, then in step S35, from the filler cap 1b. It is determined that there is a possibility of fuel leakage, and the diagnostic process is stopped.
[0039]
On the other hand, if it is determined that the leak diagnosis parameter Im-Io is smaller than the filler cap leak prevention threshold fcap1, then in step S36, it is determined whether or not the leak diagnosis parameter Im-Io is equal to or greater than the pressurization stop threshold Is1. If it is determined that the pressure stoppage threshold Is1 or more, it is determined in step S37 that there is no leak corresponding to the case where the purge system has a 0.5 mm diameter hole and that the pressure is normal.
[0040]
If it is determined in step S36 that the leak diagnosis parameter Im-Io is smaller than the pressurization stop threshold Is1, whether or not the timer value of the failure determination timer Tm is equal to or greater than the third determination threshold T (3) in step S38. If it is determined that the value is smaller than the third determination threshold value T (3), the process returns to step S32 again. On the other hand, if it is determined that the value is greater than or equal to the third determination threshold value T (3), the purge system is set to 0 in step S39. It is determined that there is a relatively small leak corresponding to the case where there is a hole with a diameter of 5 mm.
[0041]
Then, after steps S35, S37, and S39, the process proceeds to step S40 in any case, the switching valve 20 is changed from the closed state to the open state, the electric pump 14 is turned off, and the diagnosis process is terminated.
[0042]
Next, the flow of failure diagnosis will be described with reference to FIGS.
[0043]
First, as shown in FIG. 6, when the ignition switch is turned off and the engine is stopped, the remaining fuel amount FTL is detected, and the remaining fuel amount FTLm at this time is stored in the control unit 21.
[0044]
Next, when the electric pump 14 is turned on while the switching valve 20 is open, the air pressurized by the electric pump 14 is supplied to the reference orifice 19 provided in the first passage 15. In this case, as indicated by a white arrow in FIG. 2, the pressurized air passes through the reference orifice 19 whose passage is restricted, so that the load current value Im of the electric pump 14 increases abruptly. The current threshold value Iref is shown.
[0045]
When the switching valve 20 is changed from the open state to the closed state, as shown by a white arrow in FIG. 1, the pressurized air passes through the second passage 16 whose passage is relatively unrestricted to the depressurized purge system. Since the load current value Im of the electric pump 14 decreases rapidly and shows the load current initial value Io, the purge system gradually increases in pressure, so the load current value Im tends to increase. It becomes like this.
[0046]
In that case, if the filter 11 is in the closed state, the supply of air from the upstream side of the electric pump 14 is restricted, so that the load current value Im of the electric pump 14 rapidly increases as indicated by reference numeral a. On the other hand, if the filter 11 is normal, the supply of air from the upstream side of the electric pump 14 is not restricted, so that the load current value Im of the electric pump 14 is gentler than that of the symbol A, as indicated by the symbol A. To increase.
[0047]
That is, for the signs a and i, the times T1 and T2 when the respective load current values Im reach the load current threshold Iref are measured, and the times T1 and T2 are compared with the filter blockage determination threshold To. 11 blockage faults can be determined. According to the illustrated example, in the code A, the time T1 when the load current value Im reaches the load current threshold value Iref is shorter than the filter blockage determination threshold value To. In this case, it is determined that the filter 11 may have a blockage failure. On the other hand, since the time T2 for the load current value Im to reach the load current threshold value Iref is equal to or longer than the filter blockage determination threshold value To in the symbol A, in this case, it is determined that the filter 11 has no possibility of blockage failure.
[0048]
In the case of the above code A, the switching valve 20 is changed from the closed state to the open state and the electric pump 14 is turned off in order to determine whether or not refueling is performed during the determination of the closed state of the filter 11 next. Is done. If the ignition switch is turned on and the engine is started, and the difference between the remaining fuel amount FTL and the remaining fuel amount FTLm when the ignition switch is turned off is greater than or equal to the fuel supply determination threshold fkyu, the fuel pump 11 It is determined that the load current value Im of the electric pump 14 has reached the load current threshold value Iref at time T1 due to the fact that the fuel has been supplied, while the fuel remaining amount FTL and the ignition switch when the ignition switch is turned on are OFF. If the difference from the remaining fuel amount FTLm is smaller than the fuel supply determination threshold fkyu, the fuel supply is not performed, and the load current value Im of the electric pump 14 becomes the load current threshold Iref at time T1 due to the blockage failure of the filter 11. It is determined that they have arrived, and the diagnosis processing is terminated together.
[0049]
If it is determined in the above diagnosis that there is no blockage failure of the filter 11 and the filter 11 is normal, the diagnosis of the presence or absence of a leak in the purge system is subsequently executed.
[0050]
First, as shown in FIG. 7, the load current threshold Iref of the electric pump 14 is detected by the reference symbol P <b> 1, and then the switching valve 20 is changed from the open state to the closed state by the reference symbol P <b> 2. An initial value Io is detected.
[0051]
In the case of the code C, the timer value of the failure determination timer Tm increases, and the timer value of the failure determination timer Tm becomes the first determination threshold value T (1) at the code P3. It is determined whether Io is larger than the large leak determination threshold f1. In this case, since the leak diagnosis parameter Im-Io is larger than the large leak determination threshold f1, the pressurization stop threshold Is1 and the filler cap leak prevention threshold fcap1 are calculated.
[0052]
Subsequently, the load current value Im is detected as the timer value of the failure determination timer Tm increases, and it is determined whether or not the diagnostic parameter Im-Io at that time is smaller than the filler cap leakage prevention threshold fcap1. In this case, since the parameter Im-Io is smaller than the filler cap leakage prevention threshold fcap1, it is next determined whether or not the diagnostic parameter Im-Io is equal to or greater than the pressurization stop threshold Is1. In this case, since the leak diagnosis parameter Im-Io becomes the same value as the pressurization stop threshold Is1 at the reference symbol P4, it is determined that there is no leak in the purge system at this point, and the diagnosis process ends. .
[0053]
Next, in the case of code D, since the timer value of the failure determination timer Tm has reached the first determination threshold value T (1) in the code P5, is the leak diagnosis parameter Im-Io at that time larger than the large leak determination threshold value f1? It is determined whether or not. In this case, since the parameter Im-Io is equal to or smaller than the large leak determination threshold f1, when the timer value of the failure determination timer Tm further increases and the timer value becomes the second determination threshold T (2), that is, At P6, it is determined whether or not the leak diagnosis parameter Im-Io at that time is larger than the 1 mm diameter leak determination threshold f2. In this case, since the parameter Im-Io is larger than the 1 mm diameter leak determination threshold f2, next, the pressurization stop threshold Is1 and the filler cap leak prevention threshold fcap1 are calculated.
[0054]
Then, the load current value Im is detected with the increase of the timer value of the failure determination timer Tm, and it is determined whether or not the leak diagnosis parameter Im-Io is smaller than the filler cap leak prevention threshold fcap1. In this case, since the parameter Im-Io is smaller than the filler cap leakage prevention threshold fcap1, it is determined that there is no fuel leakage failure in the filler cap 1b. Next, the timer value of the failure determination timer Tm is the third determination threshold T ( 3) It is determined whether or not. When the timer value of the failure determination timer Tm reaches the third determination threshold value T (3), that is, with reference P7, it is determined that there is a leak corresponding to the case where the purge system has a 0.5 mm diameter hole. The diagnosis process is terminated.
[0055]
Next, in the case of code O, since the timer value of the failure determination timer Tm has reached the first determination threshold value T (1) in code P8, is the leak diagnosis parameter Im-Io at that time larger than the large leak determination threshold value f1? It is determined whether or not. In this case, since the parameter Im-Io is equal to or smaller than the large leak determination threshold f1, when the timer value of the failure determination timer Tm further increases and the timer value becomes the second determination threshold T (2), that is, At P9, it is determined whether or not the leak diagnosis parameter Im-Io at that time is larger than the 1 mm diameter leak determination threshold f2. In this case, since the parameter Im-Io is equal to or less than the 1 mm diameter leak determination threshold f2, it is determined that there is a large leak in the purge system, and the diagnosis process is terminated.
[0056]
In this way, by diagnosing the blockage state of the filter 11 at the initial stage of diagnosis of the presence or absence of a leak in the purge system, it is possible to avoid diagnosing the blockage failure of the filter 11 and the normal state without leak, The diagnostic accuracy of the fault is improved. In this case, since it is determined whether or not refueling is being performed during the determination of the closed state of the filter 11, the diagnosis accuracy of the blocked failure of the filter 11 is improved.
[0057]
Then, pressurized air is supplied to the reference orifice 19 by the electric pump 14, and a purge system hole corresponding to the diameter of the reference orifice 19 is created by using the load current threshold Iref of the electric pump 14 at that time as a reference. It becomes possible to detect reliably.
[0058]
In the above embodiment, the closed state of the filter 11 is determined based on the load current value Im of the electric pump 14, but is determined based on the rotational speed of the electric pump 14, the pressure in the fuel tank 1, or the like. Also good. Further, the presence or absence of leakage in the purge system is determined by the leak diagnosis parameter Im-Io based on the load current value Im of the electric pump 14, but as described above, based on the rotational speed of the electric pump 14, the pressure in the fuel tank 1, and the like. You may judge. In any case, similarly to the above embodiment, it is possible to reliably diagnose the clogging failure of the filter 11 and the presence or absence of a leak in the purge system.
[0059]
In the above embodiment, whether or not refueling is being performed is determined by detecting the remaining fuel amount FTL in the fuel tank 1 by the remaining amount sensor 6, but the filler cap 1b is opened or closed. It may be determined whether or not refueling is performed by detecting.
[0060]
【The invention's effect】
As described above, according to the present invention, the air introduced through the filter is pressurized by the electric pump and supplied to the purge system from the fuel tank to the purge valve, thereby determining whether or not there is a leak in the purge system. In the failure diagnosis device for the evaporated fuel processing device to be diagnosed, the filter blockage failure is diagnosed prior to the leak diagnosis, so that the erroneous diagnosis is prevented and the accuracy of the leak diagnosis can be improved. The present invention is widely suitable for the vehicle field provided with a failure diagnosis device for an evaporated fuel processing device.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a failure diagnosis apparatus for an evaporated fuel processing apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic view when the switching valve is in an open state.
FIG. 3 is a flowchart showing an example of failure diagnosis processing.
FIG. 4 is also a flowchart diagram.
FIG. 5 is a flowchart of the same.
FIG. 6 is a time chart for diagnosing a filter blockage fault.
FIG. 7 is a diagram showing a relationship between a load current value and time when diagnosing the presence or absence of a leak.
[Explanation of symbols]
1 Fuel tank
5 Purge valve
7 Diagnosis unit (Failure diagnosis device)
11 Filter
14 Electric pump (pressurizing means)
15 First passage
16 Second passage
19 Reference orifice
20 Switching valve (switching means)
21 Control unit (pressure control means, diagnostic means, timing means, blockage determination means, oil supply determination means, blockage determination prohibition means)

Claims (3)

A pressurizing means for pressurizing and supplying air introduced through a filter to a purge system of evaporated fuel from the fuel tank to the purge valve, and provided between the pressurizing means and the purge system, A pressure passage composed of a first passage for supplying pressurized air, a second passage for bypassing the orifice and supplying pressurized air to the purge system, and first and second passages of the pressure passage When the predetermined diagnostic condition is satisfied, the switching means first shuts off the second passage and supplies pressurized air to the reference orifice of the first passage, and then communicates the second passage with the switching passage. Pressurization control means for supplying pressurized air to the purge system through the second passage, and diagnostic means for diagnosing the presence or absence of leak in the purge system based on a change in parameters corresponding to the presence or absence of leak in the purge system at that time And set When the pressurized air is supplied to the reference orifice by the pressurizing means and then the pressurized air is supplied to the purge system after the pressurized air is supplied to the purge system, Time measuring means for measuring a time until reaching a value when pressurized air is supplied to the reference orifice, and a blockage for determining that the filter is in a closed state when the time measured by the time measuring means is a predetermined value or less A failure diagnosis apparatus for an evaporated fuel processing apparatus, comprising: a determination unit. The blockage determination means is configured to determine whether or not the filter is closed when the engine is stopped, and when the determination means determines that the filter is closed, during the determination A fuel determination unit that determines whether or not fuel has been supplied to the fuel tank after completion of the determination , and when the fuel determination unit determines that the fuel has been supplied , the filter by the blockage determination unit is in a closed state. The failure diagnosis apparatus for an evaporated fuel processing apparatus according to claim 1, further comprising: occlusion determination cancellation means that cancels the determination that the filter is present and determines that the filter is normal . The fuel supply determination means determines whether or not fuel supply is performed based on a change in the remaining amount of fuel between when the engine is stopped and when the engine is operated next. A failure diagnosis apparatus for the fuel vapor processing apparatus according to claim.

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