JP2020026758A - Evaporation fuel treatment device - Google Patents

Abstract

To provide an evaporation fuel treatment device which can determine the presence or absence of the clogging of a passage at an upstream side of a purge pump by easy control.SOLUTION: This evaporation fuel treatment device 1 has a passage clogging determination part 21 for determining the presence or absence of the clogging of a pump upstream-side passage 22 including a vapor passage 16 and an upstream-side passage 12a in a purge passage 12. When an engine ENG is stopped, or purge control is stopped, the passage clogging determination part 21 brings an atmosphere cutoff valve 19 into a valve-closing state, drives a purge pump 13, and determines the presence or absence of the clogging of the pump upstream-side passage 22 on the basis of a rise situation of pressure in the pump upstream-side passage 22 when applying positive pressure to the pump upstream-side passage 22.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an evaporative fuel processing device that supplies evaporative fuel generated in a fuel tank to an internal combustion engine via an intake passage.

  In the evaporative fuel processing apparatus, when a purge pump is provided in a purge passage, if a clogging occurs in a passage (for example, a purge passage or a vapor passage) on the upstream side of the purge pump, the flow rate of the purge gas cannot be appropriately adjusted. , A / F roughness may occur. Therefore, it is required to detect whether the passage on the upstream side of the purge pump is clogged. Note that “A / F roughness” is an air-fuel ratio roughness in which the air-fuel ratio in the combustion chamber of the engine fluctuates excessively.

  Here, as a prior art relating to the detection of the presence or absence of an abnormality in a passage in an evaporative fuel treatment device, Patent Document 1 discloses a fuel evaporation prevention device for preventing evaporation of fuel gas generated in a fuel tank. There is disclosed an apparatus for detecting an abnormality of the device.

JP 05-125997 A

  In the device disclosed in Patent Document 1, first, when the vehicle is stopped and the vehicle is idling, the purge control valve and the canister closing valve are fully closed, and the amount of pressure change under atmospheric pressure is measured. Next, the purge control valve is temporarily switched from the fully closed state to the fully open state, a negative pressure of the intake pipe is introduced into the closed section, and the amount of pressure change under the negative pressure is measured. Then, based on the measured value of the pressure change amount under the atmospheric pressure sealing and the measured value of the pressure change amount under the negative pressure sealing, the presence or absence of an abnormality causing a leak in the sealed section is detected.

  However, in the apparatus disclosed in Patent Document 1, the presence or absence of an abnormality in a closed section is detected by measuring the amount of pressure change by setting two conditions under atmospheric pressure sealing and under negative pressure sealing. Therefore, the control for performing the detection is complicated.

  Therefore, the present disclosure has been made in order to solve the above-described problem, and has as its object to provide an evaporative fuel processing apparatus that can determine, with a simple control, whether or not the upstream passage of the purge pump is clogged. .

  One embodiment of the present disclosure made in order to solve the above-mentioned problem is connected to a vapor passage connected to a fuel tank, a canister storing evaporative fuel sent from the fuel tank via the vapor passage, and an internal combustion engine. A purge passage connected to the intake passage and the canister, a purge pump provided in the purge passage, an atmosphere passage connected to the canister, and an atmosphere shutoff valve for opening and closing the atmosphere passage. In the evaporative fuel processing device that executes purge control for introducing the purge gas containing the evaporative fuel into the intake passage through the purge passage, the vapor passage, and a passage on the upstream side of the purge pump in the purge passage. A passage clogging determination unit that determines the presence or absence of clogging in the pump upstream side passage including the passage clogging determination unit, When the internal combustion engine is stopped or the purge control is stopped, the air shutoff valve is closed, and the purge pump is driven to apply a positive pressure to the pump upstream passage. It is characterized in that the presence or absence of clogging in the pump upstream passage is determined based on a rise in the pressure in the pump upstream passage.

  According to this aspect, the presence or absence of clogging in the pump upstream passage can be determined based on the pressure increase in the pump upstream passage only by applying a positive pressure to the pump upstream passage by the purge pump. Therefore, the presence / absence of clogging of the pump upstream passage can be determined with simple control.

  In the above aspect, the passage clogging determination unit may include, as a pressure increase state in the pump upstream passage, the pump upstream passage if the pressure increase speed in the pump upstream passage is less than a predetermined determination speed. It is preferable to determine that the side passage is not clogged.

  According to this aspect, since the determination may be made based on the rate of increase in the pressure in the pump upstream passage, the presence or absence of clogging in the pump upstream passage can be determined in a short time. Therefore, when making the determination, the drive time of the purge pump can be shortened, and power consumption can be suppressed.

  In the above aspect, the passage clogging determination unit sets the pressure in the pump upstream passage in a saturating state in which a pressure difference per predetermined time of the pressure in the pump upstream passage is less than a predetermined value as a pressure increase state in the pump upstream passage. If the saturating time to reach the predetermined time is longer than a predetermined determination time, it is preferable to determine that the pump upstream passage is not clogged.

  According to this aspect, since the determination is made while observing the change in the pressure change in the pump upstream passage, it is possible to accurately determine whether the pump upstream passage is clogged.

  In the above aspect, it is preferable that the predetermined determination speed or the predetermined determination time is defined according to a remaining amount of fuel in the fuel tank.

  According to this aspect, it is possible to accurately determine whether or not the pump upstream passage is clogged regardless of the remaining amount of fuel in the fuel tank.

  In the above aspect, it is preferable that the passage clogging determination unit drives the purge pump in reverse rotation to apply a positive pressure to the pump upstream passage.

  According to this aspect, as a means for applying a positive pressure to the pump upstream passage, a purge pump having an existing configuration in the evaporative fuel processing apparatus is used without providing a new means, so that cost is reduced. Can be reduced.

  In the above aspect, there is provided a switching valve for switching a passage connected to each of the suction port and the discharge port of the purge pump, and the passage clogging determination unit causes the purge valve to purge the suction port in the purge passage by the switching valve. While the discharge port is connected to a passage on the upstream side of the purge pump in the purge passage while the discharge port is connected to a passage on the downstream side of the pump, the purge pump is driven in a forward rotation, thereby the pump upstream side. Preferably, a positive pressure is applied to the passage.

  According to this aspect, the purge pump does not need to be driven in the reverse rotation. Therefore, a pump capable of one-way operation (only positive rotation) can be used as the purge pump. Therefore, regardless of the type of the pump used as the purge pump, it is possible to determine whether there is a clog in the pump upstream passage.

  According to the evaporated fuel processing device of the present disclosure, it is possible to determine whether or not the passage on the upstream side of the purge pump is clogged with a simple control.

1 is a schematic configuration diagram of an evaporative fuel processing system including an evaporative fuel processing apparatus according to first and second embodiments and a periphery thereof; FIG. 3 is a diagram illustrating a control flowchart according to the first embodiment. FIG. 4 is a diagram illustrating an example of a map that defines a relationship between a remaining tank amount and a determination value. It is a figure showing an example of a control time chart in a 1st embodiment. It is a figure showing a switching valve. It is a figure showing a control flow chart in a 2nd embodiment. FIG. 4 is a diagram illustrating an example of a map that defines a relationship between a remaining amount of a tank and a determination time. It is a figure showing an example of a control time chart in a 2nd embodiment.

  Hereinafter, embodiments of the evaporated fuel processing device of the present disclosure will be described.

[First Embodiment]
First, a first embodiment will be described.

<Overview of evaporative fuel processing device>
An outline of the evaporated fuel processing device 1 of the present embodiment will be described. The fuel vapor processing apparatus 1 is used for a vehicle such as an automobile.

  Here, as shown in FIG. 1, an intake passage IP for supplying air (intake air, intake air) to the engine ENG is connected to an engine ENG (internal combustion engine) mounted on the vehicle. The intake passage IP is provided with an electronic throttle THR (throttle valve) for opening and closing the intake passage IP to control the amount of air (intake air amount) flowing into the engine ENG. An air cleaner AC that removes foreign matter from the air flowing into the intake passage IP is provided upstream of the electronic throttle THR in the intake passage IP (upstream in the flow direction of the intake air). Thus, in the intake passage IP, air passes through the air cleaner AC and is sucked toward the engine ENG.

  The evaporated fuel processing device 1 of the present embodiment is a device that supplies the evaporated fuel in the fuel tank FT to the engine ENG via the intake passage IP. As shown in FIG. 1, the fuel vapor processing apparatus 1 includes a canister 11, a purge passage 12, a purge pump 13, a purge control valve 14 (purge valve), an atmospheric passage 15, a vapor passage 16, and a control unit 17. , A filter 18, an atmosphere cutoff valve 19, a pressure sensor PS1 (first pressure sensor), a pressure sensor PS2 (second pressure sensor), and the like.

  The canister 11 is connected to the fuel tank FT via the vapor passage 16 and stores the evaporated fuel flowing from the fuel tank FT via the vapor passage 16. The canister 11 communicates with the purge passage 12 and the atmosphere passage 15.

  The purge passage 12 is connected to the intake passage IP and the canister 11. As a result, the purge gas (gas containing evaporated fuel) flowing out of the canister 11 flows through the purge passage 12 and is introduced into the intake passage IP. In the example shown in FIG. 1, the purge passage 12 is connected to a position downstream of the electronic throttle THR (downstream in the direction of flow of the intake air) in the intake passage IP, but is not limited to this. It may be connected to a position on the upstream side of the electronic throttle THR.

  The purge pump 13 is provided in the purge passage 12 and controls a flow of a purge gas flowing through the purge passage 12. That is, the purge pump 13 sends the purge gas in the canister 11 to the purge passage 12, and supplies the purge gas sent to the purge passage 12 to the intake passage IP.

  The purge control valve 14 is provided in the purge passage 12 at a position downstream of the purge pump 13 (downstream in the flow direction of the purge gas at the time of executing the purge control), that is, at a position between the purge pump 13 and the intake passage IP. Have been. The purge control valve 14 opens and closes the purge passage 12. When the purge control valve 14 is closed (when the valve is closed), the purge gas in the purge passage 12 is stopped by the purge control valve 14 and does not flow toward the intake passage IP. On the other hand, when the purge control valve 14 is opened (when the valve is open), the purge gas flows toward the intake passage IP.

  One end of the atmosphere passage 15 is open to the atmosphere, and the other end is connected to the canister 11, and connects the canister 11 to the atmosphere. Then, the air taken in from the atmosphere flows through the atmosphere passage 15.

  The vapor passage 16 is connected to the fuel tank FT and the canister 11. As a result, the fuel vapor from the fuel tank FT flows into the canister 11 via the vapor passage 16.

  The control unit 17 is a part of an ECU (not shown) mounted on the vehicle, and is arranged integrally with another part of the ECU (for example, a part that controls the engine ENG). Note that the control unit 17 may be arranged separately from other parts of the ECU. The control unit 17 includes a CPU and a memory such as a ROM and a RAM. The control unit 17 controls the evaporated fuel processing device 1 and the evaporated fuel processing system according to a program stored in the memory in advance. For example, the control unit 17 controls the purge pump 13 and the purge control valve 14. Further, the control unit 17 acquires a pressure detection result from the pressure sensors PS1 and PS2.

  In the present embodiment, the control unit 17 includes a passage blockage determination unit 21. The passage blockage determination unit 21 determines whether there is a blockage in the pump upstream-side passage 22. Here, the “pump upstream passage 22” is an upstream passage of the purge pump 13, and includes a vapor passage 16, an upstream passage 12 a upstream of the purge pump 13 in the purge passage 12, and an air passage 15. And a downstream passage 15 a downstream of the air cutoff valve 19. The “upstream side of the purge pump 13” refers to the upstream side in the flow direction of the purge gas at the time of executing the purge control, that is, the canister 11 side. Further, “downstream side of the atmosphere shutoff valve 19” means the downstream side in the flow direction of the atmosphere (air), that is, the canister 11 side. Further, the passage clogging determination unit 21 may be provided independently of the control unit 17.

  The filter 18 removes foreign matters from the atmosphere (air) flowing into the atmosphere passage 15. The atmosphere shutoff valve 19 opens and closes the atmosphere passage 15.

  The pressure sensor PS1 and the pressure sensor PS2 detect the pressure in the pump upstream passage 22. In the example shown in FIG. 1, the pressure sensor PS1 is provided in the upstream passage 12a in the purge passage 12 of the pump upstream passage 22, and detects the pressure in the upstream passage 12a. Further, the pressure sensor PS2 is provided in the downstream passage 15a in the atmospheric passage 15 in the pump upstream passage 22, and detects the pressure in the downstream passage 15a. The position where the pressure sensor PS1 and the pressure sensor PS2 are provided is not limited to the position shown in FIG. 1, but may be provided at any position of the pump upstream passage 22 (for example, the vapor passage 16). I just need.

  In the evaporative fuel processing apparatus 1 having such a configuration, when the purge condition is satisfied during the operation of the engine ENG, the control unit 17 controls the purge pump 13 and the purge control valve 14, that is, rotates the purge pump 13 forward. , The purge control valve 14 is opened to perform the purge control. The purge control is a control for introducing a purge gas from the canister 11 into the intake passage IP via the purge passage 12.

  During the execution of the purge control, the engine ENG supplies air to the intake passage IP, fuel injected from the fuel tank FT via an injector (not shown), and the intake passage IP by the purge control. , And a purge gas supplied to Then, the control unit 17 adjusts the air-fuel ratio (A / F) of the engine ENG to an optimal air-fuel ratio (for example, an ideal air-fuel ratio) by adjusting the injection time of the injector, the valve opening time of the purge control valve 14, and the like. I do.

<Control for judging the presence or absence of clogging in the pump upstream passage>
As a self-diagnosis function (On-board diagnostics, OBD) of the vehicle, when the presence or absence of clogging of the pump upstream passage 22 including the vapor passage 16 is determined while the vehicle is traveling, the influence of the determination operation is obtained. As a result, the flow rate of the purge gas (the flow rate of the purge gas) may decrease while the vehicle is running. Then, the air-fuel ratio of the engine ENG may not be adjusted to the optimum air-fuel ratio.

  Therefore, in the present embodiment, control is performed to determine whether there is a clog in the pump upstream passage 22 including the vapor passage 16 while preventing the purge flow rate from decreasing during traveling of the vehicle.

  Specifically, the passage blockage determination unit 21 of the control unit 17 performs control based on the control chart shown in FIG.

  As shown in FIG. 2, when it is immediately after the engine ENG has stopped (step S <b> 1: YES), the passage blockage determination unit 21 opens the purge control valve 14 (opens the valve), while the air shutoff valve. 19 is closed (closed) (step S2).

  Next, the passage clogging determination unit 21 drives the purge pump 13 at a predetermined rotation speed (for example, 20,000 rpm) in reverse rotation (step S3). In this way, the passage clogging determination unit 21 drives the purge pump 13 in the reverse rotation to supply gas (such as intake air) to the pump upstream passage 22 and to apply a positive pressure to the pump upstream passage 22. Apply. As the purge pump 13, a pump (for example, a Wesco pump) capable of operating in two directions (forward rotation and reverse rotation) is used.

  Next, the passage blockage determination unit 21 stores the pressure P (the pressure P1, the pressure P2, and the pressure P3) for each predetermined time TA (for example, every 1 second) (Step S4). Here, the pressure P is a detection value of the pressure sensor PS1. It is also assumed that the pressure P is detected in the order of pressure P1, pressure P2, and pressure P3 over time. Note that the pressure P may be a detection value of the pressure sensor PS2.

  Next, the passage clogging determination unit 21 determines a determination value X (predetermined determination speed) from the tank remaining amount TR, which is the remaining amount of fuel in the fuel tank FT, using, for example, a map shown in FIG. Step S5). As shown in FIG. 3, the determination value X is defined corresponding to the tank remaining amount TR, and is defined to increase as the tank remaining amount TR increases.

  Next, the passage blockage determination unit 21 determines whether or not the pressure rise allowance ΔPA (the rise speed of the pressure P) is less than the determination value X (Step S6). Here, ΔPA = (P2-P1), ΔPA = (P3-P1), or ΔPA = (P3-P2).

  When the pressure rise allowance ΔPA is smaller than the determination value X (step S6: YES), the passage clogging determination unit 21 determines that the hose forming the pump upstream-side passage 22 is not clogged (step S7). . That is, when the pressure increase allowance ΔPA is less than the determination value X and the rate of increase of the pressure P is normal, it is considered that the volume of gas that can flow into the pump upstream-side passage 22 is maintained, so that the passage clogging occurs. The determination unit 21 determines that the pump upstream passage 22 is not clogged. When it is determined that the pump upstream passage 22 is not clogged, it is considered that the vapor passage 16 which is a part of the pump upstream passage 22 is not clogged.

  In this way, the passage clogging determination unit 21 determines that the pump upstream-side passage 22 is not clogged if the pressure increasing speed in the pump upstream-side passage 22 is lower than the predetermined determination speed.

  On the other hand, when the pressure increase allowance ΔPA is equal to or greater than the determination value X (step S6: NO), the passage clogging determination unit 21 determines that the hose forming the passage clogging determination unit 21 is clogged (step S8). . That is, when the pressure increase allowance ΔPA is equal to or greater than the determination value X and the rate of increase of the pressure P is higher than usual, it is considered that the volume of gas that can flow into the pump upstream-side passage 22 is small. The determination unit 21 determines that the pump upstream passage 22 is clogged. When it is determined that the pump upstream passage 22 is clogged, there is a possibility that the vapor passage 16 which is a part of the pump upstream passage 22 is clogged.

  In this way, the passage clogging determination unit 21 determines that the passage clogging determination unit 21 is clogged if the pressure increasing speed in the pump upstream passage 22 is equal to or higher than the predetermined determination speed.

  Then, the control is performed based on the control chart shown in FIG. 2 so that an example of a control time chart as shown in FIG. 4 is performed. As shown in FIG. 4, when the pressure increase allowance ΔPA (= P3−P2) is smaller than the determination value X (for example, 3 kPa), it is determined that the passage clogging determination unit 21 is normal without clogging. On the other hand, if the pressure rise allowance ΔPA is equal to or larger than the determination value X, it is determined that the passage blockage determination unit 21 is clogged and abnormal. The pressure P1 is the pressure P at the time T1, the pressure P2 is the pressure P at the time T2, and the pressure P3 is the pressure P at the time T3.

  As a modified example, in step S3 of FIG. 2, the passage clogging determination unit 21 switches the path to which the suction port 13a and the discharge port 13b of the purge pump 13 are connected by the switching valve 23 shown in FIG. A gas may be supplied to the upstream passage 22 to apply a positive pressure to the pump upstream passage 22.

  Specifically, the switching valve 23 includes a first passage portion 24 and a second passage portion 25, and the first passage portion 24 or the second passage portion 25 may be disposed between the purge pump 13 and the purge passage 12. it can.

  The first passage portion 24 includes a first passage 24a and a second passage 24b. The first passage 24 a connects the suction port 13 a of the purge pump 13 to the upstream passage 12 a in the purge passage 12. The second passage 24b connects the discharge port 13b of the purge pump 13 to the downstream passage 12b downstream of the purge pump 13 in the purge passage 12 (downstream of the flow direction of the purge gas during execution of the purge control, the intake passage IP side). To be connected.

  The second passage 25 includes a first passage 25a and a second passage 25b. The first passage 25a connects the suction port 13a of the purge pump 13 to the downstream passage 12b. The second passage 25b connects the discharge port 13b of the purge pump 13 to the upstream passage 12a.

  Then, the switching valve 23 switches the passage disposed between the purge pump 13 and the purge passage 12 to the first passage 24 or the second passage 25. Thereby, the switching valve 23 can switch the path in which the suction port 13a and the discharge port 13b of the purge pump 13 are connected to the upstream path 12a or the downstream path 12b.

  In such a modified example, the passage clogging determination unit 21 connects the suction port 13 a of the purge pump 13 to the downstream side passage 12 b in the purge passage 12 by the switching valve 23, while the discharge port of the purge pump 13 13 b is connected to the upstream passage 12 a in the purge passage 12. Then, in this state, the passage blockage determination unit 21 can drive the purge pump 13 by positive rotation to apply a positive pressure to the pump upstream passage 22.

  As a modified example, the passage clogging determination unit 21 may determine the presence or absence of clogging in the pump upstream passage 22 while the purge control is stopped while the engine ENG is operating.

<Operation and effect of the present embodiment>
As described above, in the present embodiment, the passage blockage determination unit 21 closes the air cutoff valve 19 and drives the purge pump 13 while the engine ENG is stopped or the purge control is stopped. A positive pressure is applied to the upstream passage 22. Then, the passage clogging determination unit 21 determines the presence or absence of clogging in the pump upstream-side passage 22 based on the pressure increase in the pump upstream-side passage 22 at this time.

  As described above, only by applying a positive pressure to the pump upstream passage 22 by the purge pump 13, it is determined whether or not the pump upstream passage 22 is clogged based on a rise in the pressure in the pump upstream passage 22. it can. Therefore, the presence / absence of clogging of the pump upstream passage 22 can be determined with simple control.

  Further, it is possible to determine whether the pump upstream passage 22 is clogged by using the existing configuration of the evaporative fuel processing device 1 without adding a new configuration. Therefore, it is possible to determine the presence or absence of clogging of the pump upstream passage 22 with a simple device configuration, so that cost can be reduced.

  Further, since the determination is made while the engine ENG is stopped or the purge control is stopped, the flow rate of the purge gas is not reduced when the purge control is performed while the vehicle is running, and the restriction on the timing of the determination is reduced. In addition, since it is only necessary to apply a positive pressure to the pump upstream passage 22 by the purge pump 13 and check the pressure increase in the pump upstream passage 22 once, the clogging of the pump upstream passage 22 can be shortened in a short time. Can be completed.

  Further, in this embodiment, if the pressure increase allowance ΔPA is less than the determination value X as the pressure increase state in the pump upstream passage 22, the passage clogging determination unit 21 does not cause clogging in the pump upstream passage 22. Is determined.

  In this manner, since the determination may be made based on the pressure increase allowance ΔPA of the pressure in the pump upstream passage 22, the presence or absence of clogging in the pump upstream passage 22 can be determined in a short time. Therefore, when making the determination, the drive time of the purge pump 13 can be shortened, and power consumption can be suppressed.

  Further, since the determination value X is defined in accordance with the remaining amount of fuel in the fuel tank FT, it is possible to accurately determine whether the pump upstream passage 22 is clogged regardless of the remaining amount of fuel in the fuel tank FT.

  Further, the passage clogging determination unit 21 drives the purge pump 13 in the reverse rotation, and applies a positive pressure to the pump upstream passage 22. In this manner, as means for applying a positive pressure to the pump upstream passage 22, the purge pump 13 having the existing configuration in the evaporative fuel processing apparatus 1 is used without providing a new means. Cost can be reduced.

  In addition, the passage clogging determination unit 21 connects the suction port 13 a of the purge pump 13 to the downstream passage 12 b in the purge passage 12 by using the switching valve 23, and connects the discharge port 13 b of the purge pump 13 to the upstream side in the purge passage 12. In a state where the purge pump 13 is connected to the passage 12 a, the purge pump 13 may be driven by positive rotation to apply a positive pressure to the pump upstream passage 22.

  Thus, the purge pump 13 does not need to be rotated in the reverse direction. Therefore, a pump (for example, a centrifugal pump) that can operate in one direction (only a positive rotation) can be used as the purge pump 13. Therefore, regardless of the type of pump used as the purge pump 13, the presence or absence of clogging in the pump upstream passage 22 can be determined.

[Second embodiment]
Next, a second embodiment will be described. The same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different points will be mainly described.

<Control for judging the presence or absence of clogging in the pump upstream passage>
In the present embodiment, the passage blockage determination unit 21 performs control based on a control chart shown in FIG.

  As shown in FIG. 6, the difference from the control of the first embodiment shown in FIG. 2 is that in step S14, the passage clogging determination unit 21 determines the pressure difference ΔPB for each predetermined time TB (pressure rise for each predetermined time). Is obtained (step S14).

  Next, the passage clogging determination unit 21 determines a determination time t (a predetermined determination time) from the tank remaining amount TR using, for example, a map shown in FIG. 7 (step S15). As shown in FIG. 7, the determination time t is defined corresponding to the tank remaining amount TR, and is defined to be shorter as the tank remaining amount TR increases.

  Next, the passage blockage determination unit 21 stores the saturating time ST when (pressure difference ΔPB) <(predetermined value Y) (step S16). That is, the passage blockage determination unit 21 stores the saturating time ST that is the time required until the pressure difference ΔPB reaches the saturating state where the pressure difference ΔPB becomes smaller than the predetermined value Y.

  Next, the passage blockage determination unit 21 determines whether the saturating time ST is longer than the determination time t (Step S17).

  When the saturating time ST is longer than the determination time t (step S17: YES), the passage clogging determination unit 21 determines that the hose forming the pump upstream-side passage 22 is not clogged (step S18). That is, when the saturating time ST is longer than the determination time t and a certain time is required until the pressure difference ΔPB reaches the saturating state, it is considered that the volume of gas that can flow into the pump upstream passage 22 is maintained. Therefore, the passage clogging determination unit 21 determines that the pump upstream passage 22 is not clogged.

  Thus, if the saturating time ST is longer than the predetermined determination time, the passage clogging determining unit 21 determines that the pump upstream-side passage 22 is not clogged.

  On the other hand, when the saturating time ST is equal to or shorter than the determination time t (step S17: NO), the passage clogging determination unit 21 determines that the hose forming the pump upstream-side passage 22 is clogged (step S19). That is, when the saturating time ST is equal to or less than the determination time t and the pressure difference ΔPB immediately reaches the saturating state, it is considered that the volume of gas that can flow into the pump upstream passage 22 is small. The passage clogging determination unit 21 determines that the pump upstream passage 22 is clogged.

  In this way, the passage clogging determination unit 21 determines that the pump upstream side passage 22 is clogged if the saturating time ST is equal to or shorter than the predetermined determination time.

  Then, control is performed based on such a control chart shown in FIG. 6, whereby an example of a control time chart as shown in FIG. 8 is implemented. As shown in FIG. 8, when the saturating time ST of the pressure difference ΔPB becomes the time T11 to the time T14 (when it is longer than the determination time t), it is determined that the pump upstream passage 22 is not clogged (normal). Is determined. On the other hand, when the saturating time ST of the pressure difference ΔPB becomes shorter from time T11 to time T12 (when it is equal to or less than the determination time t), it is determined that the pump upstream passage 22 is clogged (abnormal). You.

  It should be noted that the passage blockage determination unit 21 may make a normal determination when the determination time t has elapsed, and end the control.

<Operation and effect of the present embodiment>
As described above, in the present embodiment, the passage clogging determination unit 21 determines that the pressure difference ΔPB of the pressure in the pump upstream passage 22 at every predetermined time is less than the predetermined value Y as the pressure increase state in the pump upstream passage 22. If the saturating time ST required to reach the saturating state becomes longer than the determination time t, it is determined that the pump upstream passage 22 is not clogged.

  In this manner, since the determination is made while observing the change in the pressure change in the pump upstream passage 22, it is possible to accurately determine whether the pump upstream passage 22 is clogged.

  The above-described embodiment is merely an example, and does not limit the present disclosure in any way. It goes without saying that various improvements and modifications can be made without departing from the gist of the present disclosure.

REFERENCE SIGNS LIST 1 evaporated fuel processing device 11 canister 12 purge passage 12 a upstream passage 13 purge pump 13 a suction port 13 b discharge port 14 purge control valve 15 air passage 15 a downstream passage 16 vapor passage 17 control unit 19 air cutoff valve 21 passage clogging determination unit 22 Pump upstream passage 23 Switching valve 24 First passage 25 Second passage PS1 Pressure sensor PS2 Pressure sensor ENG Engine IP Intake passage THR Electronic throttle FT Fuel tank TA Predetermined time P, P1, P2, P3 Pressure TR Tank remaining amount X Judgment value ΔPA Pressure rise allowance ΔPB Pressure difference TB (every predetermined time) Predetermined time t Judgment time Y Predetermined value ST Saturation time

Claims (6)

A vapor passage connected to a fuel tank, a canister storing evaporative fuel sent from the fuel tank via the vapor passage, an intake passage connected to an internal combustion engine, a purge passage connected to the canister, and the purge passage Purge gas, an atmosphere passage connected to the canister, and an atmosphere shutoff valve for opening and closing the atmosphere passage. A purge gas containing the evaporated fuel from the canister to the intake passage via the purge passage. In the evaporative fuel processing device that performs purge control to introduce
A path clogging determination unit that determines whether there is clogging in a pump upstream path including the vapor path and a path upstream of the purge pump in the purge path;
The passage clogging determination unit closes the air cutoff valve while the internal combustion engine is stopped or the purge control is stopped, and drives the purge pump to move the purge upstream passage to the pump upstream passage. Judging the presence or absence of clogging in the pump upstream passage based on a pressure increase state in the pump upstream passage when a positive pressure is applied,
An evaporated fuel processing apparatus characterized by the above-mentioned. The fuel vapor treatment device according to claim 1,
The passage clogging determination unit may determine that the pump upstream passage is clogged if the pressure increase speed in the pump upstream passage is less than a predetermined determination speed as the pressure increase state in the pump upstream passage. Judge that they have not
An evaporated fuel processing apparatus characterized by the above-mentioned. The fuel vapor treatment device according to claim 1,
The passage clogging determination unit is configured to determine, as a pressure increase state in the pump upstream passage, a saturating time until a pressure difference per predetermined time of the pressure in the pump upstream passage reaches a saturating state in which the pressure difference is less than a predetermined value. If it is longer than the predetermined determination time, it is determined that the pump upstream side passage is not clogged,
An evaporated fuel processing apparatus characterized by the above-mentioned. The fuel vapor treatment device according to claim 2 or 3,
The predetermined determination speed or the predetermined determination time is defined corresponding to the remaining amount of fuel in the fuel tank,
An evaporated fuel processing apparatus characterized by the above-mentioned. In the fuel vapor processing apparatus according to any one of claims 1 to 4,
The passage clogging determination unit drives the purge pump in a reverse rotation to apply a positive pressure to the pump upstream passage.
An evaporated fuel processing apparatus characterized by the above-mentioned. In the vaporized fuel processing device according to any one of claims 1 to 4,
A switching valve for switching a passage connected to the suction port and the discharge port of the purge pump,
The passage clogging determination unit connects the suction port to a passage downstream of the purge pump in the purge passage by the switching valve, and connects the discharge port to a passage upstream of the purge pump in the purge passage. By driving the purge pump in a positive rotation while connected to a positive pressure to the pump upstream passage,
An evaporated fuel processing apparatus characterized by the above-mentioned.

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