JP2018131922A - Evaporative fuel treatment device and method for determining state of evaporative fuel treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine whether piping for supplying evaporative fuel to an intake pipe has a clogging abnormality.SOLUTION: An evaporative fuel treatment device includes an intake pipe, a canister, a purge passage, a first valve, a pump, an atmosphere passage, a second valve and a pressure gauge. Air to be supplied to an internal combustion engine passes through the intake pipe. The canister sucks evaporative fuel evaporated in a fuel tank. The purge passage connects the intake pipe with the canister. The first valve is provided in the purge passage to control purge gas supply amount to the intake pipe. The pump is provided in the purge passage between the canister and the first valve to pump out purge gas into the intake pipe. The atmosphere passage is connected to the canister and has one end opened to the atmosphere. The second valve is provided in the atmosphere passage to control an opening of the atmosphere passage. The pressure gauge is provided in a passage between the pump and the second valve to detect pressure in the passage.SELECTED DRAWING: Figure 1

Description

  The present specification relates to a fuel vapor processing apparatus. The present specification also relates to a determination method for determining the state of the evaporative fuel processing apparatus, in particular, the presence or absence of a clogged purge passage that supplies purge gas containing evaporative fuel to an intake pipe.

  Patent Document 1 discloses an evaporative fuel processing apparatus. The evaporated fuel processing apparatus of Patent Document 1 includes an intake pipe, a canister that adsorbs evaporated fuel, a purge passage that connects the intake pipe and the canister, a first valve that controls a purge gas supply amount to the intake pipe, An atmospheric passage connected to the canister and having one end open to the atmosphere, a pump provided in the atmospheric passage and exhausting purge gas to the atmosphere, and a pressure in the atmospheric passage between the canister and the pump are detected. A pressure gauge is provided.

  In Patent Document 1, the first valve is opened, the pump is driven, the gas in the passage (purge passage, atmospheric passage) is discharged to the intake pipe and the atmosphere, and a change in the pressure gauge is detected. Since gas is discharged from both ends of the passage, the pressure in the passage decreases. When the detected value of the pressure gauge falls below a predetermined value, it is determined that there is no abnormality in the passage. Further, when outside air flows into the passage and the detection value of the pressure gauge does not reach a predetermined value, it is determined that an abnormality has occurred in the passage.

Japanese Patent Laid-Open No. 2006-176337

  In Patent Document 1, the fuel vapor processing apparatus is driven under the condition that the pressure in the passage (purge passage, atmospheric passage) becomes negative, and the state of the passage (normal or abnormal) depends on whether or not the outside air flows into the passage. ). The evaporative fuel processing apparatus of Patent Document 1 can detect an abnormality such as breakage of a passage or a purge passage being disconnected from an intake pipe. However, even if the passage is not damaged and the purge passage is normally connected to the intake pipe, the purge gas cannot be supplied to the intake pipe if the purge passage is clogged. The evaporative fuel processing apparatus of Patent Document 1 cannot determine whether or not the purge passage is clogged. The present specification discloses an evaporated fuel processing apparatus capable of determining whether or not the purge passage is clogged.

  The fuel vapor processing apparatus disclosed in the present specification may include an intake pipe, a canister, a purge passage, a first valve, a pump, an atmospheric passage, a second valve, and a pressure gauge. The air supplied to the internal combustion engine may pass through the intake pipe. The canister may adsorb the evaporated fuel evaporated in the fuel tank. The purge passage may connect the intake pipe and the canister. The first valve is provided in the purge passage and may control the supply amount of the purge gas to the intake pipe. The pump is provided in the purge passage between the canister and the first valve, and the purge gas may be sent into the intake pipe. The atmospheric passage is connected to the canister, and one end may be open to the atmosphere. The second valve is provided in the atmospheric passage and may control the opening degree of the atmospheric passage. The pressure gauge is provided in the passage between the pump and the second valve, and may detect the pressure in the passage.

  In the evaporative combustion processing apparatus, a pump is provided in the purge passage, a second valve is provided in the atmospheric passage, and a pressure gauge is provided between the pump and the second valve. Therefore, when the purge passage and the intake pipe are in communication (the first valve is open), the second valve is closed and the pump is driven, so that the passage upstream of the pump (between the pump and the second valve) The pressure change in the passage) can be detected. The “passage between the pump and the second valve” includes both the purge passage and the atmospheric passage. When the pump is driven in the forward rotation, the pressure in the passage upstream of the pump decreases, and when the pump is driven in the reverse rotation, the pressure in the passage upstream of the pump increases. “Driving the pump in the forward direction” means driving the pump so as to send the gas toward the intake pipe. “Driving the pump in the reverse direction” means driving the pump so as to send the gas toward the canister.

  When the pump is driven in the forward rotation in the first valve open state and the second valve closed state, the gas in the passage is supplied to the intake pipe, and the pressure upstream of the pump decreases. If the purge passage is clogged, the gas in the passage will not be supplied to the intake pipe. Compared to the state where the purge passage is not clogged (the purge passage and the intake pipe are in communication). The amount of pressure drop upstream of the pump is reduced. Further, when the pump is driven in reverse rotation in the first valve open state and the second valve closed state, the gas in the intake pipe is supplied into the passage, and the pressure upstream of the pump increases. If the purge passage is clogged, the gas in the intake pipe is not supplied to the passage, so that the pressure increase amount upstream of the pump is smaller than in the state where the purge passage is not clogged. The evaporative fuel processing device described above drives the pump with the first valve opened and the second valve closed, and detects the pressure change in the passage upstream of the pump (between the pump and the second valve). It can be determined whether or not clogging has occurred.

  The determination method for determining whether there is a clogging abnormality in the purge passage disclosed in the present specification is that the first fuel valve is opened, the second valve is closed, the pump is driven, The pressure P1 in the passage between the first valve and the second valve is detected, and the detected pressure P1 is compared with a determination value based on the pressure P1 when the intake pipe and the purge passage are connected. The presence or absence of clogging abnormality in the inside is determined.

1 shows an outline of a fuel vapor processing apparatus according to a first embodiment. The figure for demonstrating a 1st determination method is shown (pump forward rotation). The flowchart of a 1st determination method is shown. The figure for demonstrating a 2nd determination method is shown (pump reverse rotation). The flowchart of the 2nd determination method is shown.

  The technical features disclosed in this specification are listed below. Note that the technical elements described below are independent technical elements, and exhibit technical usefulness alone or in various combinations.

  The fuel vapor processing apparatus disclosed in the present specification may include an intake pipe, a canister, a purge passage, a first valve, a pump, an air passage, a second valve, and a pressure gauge. The air supplied to the internal combustion engine may pass through the intake pipe. The intake pipe may be provided with a supercharger. The canister may adsorb the evaporated fuel evaporated in the fuel tank. The purge passage may connect the intake pipe and the canister. When the supercharger is provided in the intake pipe, the purge passage may be connected to the intake pipe upstream of the supercharger. A purge gas (a gas containing evaporated fuel) sent from the canister to the internal combustion engine may pass through the purge passage. The first valve may be provided in the purge passage. The first valve may control the purge gas supply amount to the intake pipe.

  The pump may be provided upstream (canister side) from the first valve. A pump may be provided in the purge passage between the canister and the first valve. The pump may send purge gas into the intake pipe. The atmospheric passage is connected to the canister, and one end may be open to the atmosphere. The atmospheric passage may be provided with a second valve that controls the opening degree of the atmospheric passage. The pressure gauge may be provided in a passage between the pump and the second valve, and may detect a pressure in the passage. The pressure gauge may be provided in a passage (purge passage) between the pump and the canister, or may be provided in a passage (atmospheric passage) between the canister and the second valve. A second pressure gauge that detects the pressure in the purge passage may be provided in the purge passage on the downstream side of the pump. The second pressure gauge may be provided in the purge passage downstream of the pump, and may be provided between the pump and the first valve, or may be provided downstream of the first valve. .

  The evaporative fuel processing device controls the first valve, the second valve, and the pump in a specific state, and detects whether the purge passage is clogged by detecting the pressure in the passage upstream of the pump. It can be carried out. The pump may be of a type that can be switched between forward and reverse rotation. When supplying the purge gas to the intake pipe, the pump can be driven in the forward direction, and when determining the state of the purge passage (presence of clogging), the pump can be driven in the reverse direction. By driving the pump in the reverse rotation, the state of the purge passage can be determined without supplying purge gas to the intake pipe. The influence on the air-fuel ratio of the internal combustion engine can be suppressed. The fuel vapor processing apparatus includes a control unit for controlling the first valve, the second valve and the pump, detecting the pressure in the passage by a pressure gauge, and determining the state of the purge passage based on the detected pressure value. It may be.

  The above-described method for determining the state of the purge passage (presence / absence of clogging) in the fuel vapor processing apparatus may be performed with the first valve open, the second valve closed, and the pump driven. Accordingly, the gas can be moved from the purge passage to the intake pipe or the gas can be moved from the intake pipe to the purge passage in a state where the purge passage and the outside air are prohibited from communicating via the atmospheric passage. In the determination method, the pressure P1 in the passage between the pump and the second valve is detected, and the detected pressure P1 is compared with a determination value based on the pressure P1 when no clogging occurs in the purge passage. Thus, the presence or absence of clogging abnormality in the purge passage may be determined. The pressure P1 may be detected by either the purge passage or the canister as long as it is a passage between the pump and the second valve.

  The determination value may be different from the pressure P1 when no clogging occurs in the purge passage. When the pump is driven in the positive rotation, the pressure P1 becomes a negative pressure. In this case, the determination value α1 may be larger than the pressure P1 when the purge passage is not clogged. For example, the determination value α1 may be 2 to 5 kPa greater than the pressure P1 when the purge passage is not clogged. In this case, the detected pressure P1 is compared with the determination value α1, and when (pressure P1 ≧ determination value α1), it can be determined that the purge passage is clogged. The pressure P1 (negative pressure) when no clogging occurs in the purge passage may be determined based on the pressure increase characteristic of the pump (the ability to reduce the pressure upstream of the pump). That is, the determination value α1 when the pump is driven in the forward rotation may be 2 to 5 kPa larger than the pressure P1 determined based on the boosting characteristic of the pump.

  When the pump is driven in reverse rotation, the pressure P1 becomes a positive pressure (greater than atmospheric pressure). In this case, the determination value α2 may be smaller than the pressure P1 when the purge passage is not clogged. The determination value α2 may be 2 to 5 kPa less than the pressure P1 when the purge passage is not clogged. In this case, the pressure P1 is compared with the determination value α2, and when (pressure P1 ≦ determination value α2), it can be determined that the purge passage is clogged. Note that the pressure P1 (positive pressure) when no clogging occurs in the purge passage may also be determined based on the pressure increase characteristic of the pump. That is, the determination value α2 when the pump is driven in reverse rotation may be 2 to 5 kPa smaller than the pressure P1 determined based on the boosting characteristic of the pump. The determination values α1 and α2 may be stored in a memory or the like of the control unit.

(First embodiment)
The evaporative fuel processing apparatus 10 will be described with reference to FIG. The evaporated fuel processing apparatus 10 includes a fuel supply system 2 and a purge gas supply system 8. The evaporated fuel processing apparatus 10 is mounted on a vehicle such as an automobile. The purge gas supply system 8 is connected to the fuel supply system 2 that supplies the fuel stored in the fuel tank FT to the engine EN.

  The fuel supply system 2 supplies fuel injected from a fuel pump (not shown) accommodated in the fuel tank FT to the injector IJ. The injector IJ has an electromagnetic valve whose opening degree is adjusted by an ECU (abbreviation of engine control unit) 100 described later. The injector IJ injects fuel into the engine EN.

  An intake pipe IP and an exhaust pipe EP are connected to the engine EN. The intake pipe IP is a pipe for supplying air to the engine EN by the negative pressure of the engine EN or the operation of the supercharger CH. A throttle valve TV is disposed in the intake pipe IP. The throttle valve TV is disposed downstream of the supercharger CH and upstream of the intake manifold IM. The amount of air flowing into the engine EN is controlled by adjusting the opening of the throttle valve TV. That is, the throttle valve TV controls the intake amount of the engine EN. The throttle valve TV is controlled by the ECU 100.

  A supercharger CH is arranged upstream of the throttle valve TV of the intake pipe IP. The supercharger CH is a so-called turbocharger, and rotates the turbine by the gas exhausted from the engine EN to the exhaust pipe EP, whereby the air in the intake pipe IP is pressurized and supplied to the engine EN. The supercharger CH is controlled by the ECU 100 to operate when the rotational speed N of the engine EN exceeds a predetermined rotational speed (for example, 2000 rotations).

  An air cleaner AC is disposed upstream of the supercharger CH of the intake pipe IP. The air cleaner AC has a filter that removes foreign substances from the air flowing into the intake pipe IP. In the intake pipe IP, when the throttle valve TV is opened, air passes through the air cleaner AC and is sucked toward the engine EN. The engine EN burns fuel and air inside, and exhausts the exhaust pipe EP after combustion.

  The upstream side of the supercharger CH of the intake pipe IP is open to the atmosphere via an air cleaner AC. Therefore, the pressure in the intake pipe IP upstream of the supercharger CH is atmospheric pressure. Hereinafter, the intake pipe IP upstream of the supercharger CH is referred to as an atmospheric pressure portion 56.

  The ECU 100 is connected to an air-fuel ratio sensor 50 disposed in the exhaust pipe EP. The ECU 100 detects the air-fuel ratio in the exhaust pipe EP from the detection result of the air-fuel ratio sensor 50, and controls the fuel injection amount from the injector IJ.

  The ECU 100 is connected to an air flow meter 52 disposed near the air cleaner AC. The air flow meter 52 is a so-called hot wire type aero flow meter, but may have other configurations. ECU 100 receives a signal indicating the detection result from air flow meter 52 and detects the amount of air supplied to intake pipe IP.

  When the supercharger CH is stopped, negative pressure is generated in the intake manifold IM by driving the engine EN. In addition, when stopping the engine EN when the vehicle is stopped, or when the engine EN is stopped and the vehicle is driven by a motor like a hybrid vehicle, in other words, when the drive of the engine EN is controlled for environmental measures, the engine There is no or little negative pressure in the intake manifold IM due to the EN drive. On the other hand, in a situation where the supercharger CH is operating, the downstream side of the supercharger CH is a positive pressure, and the upstream side of the supercharger CH is an atmospheric pressure.

  The purge gas supply system 8 supplies the evaporated fuel (purge gas) in the fuel tank FT to the engine EN via the intake pipe IP. The purge gas supply system 8 includes a canister 14, a pump 12, a gas pipe 32, and a purge control valve 34. The gas pipe 32 is an example of a purge passage, and the purge control valve 34 is an example of a first valve. The canister 14 adsorbs the evaporated fuel generated in the fuel tank FT. The canister 14 includes an activated carbon 14d and a case 14e that accommodates the activated carbon 14d. The case 14e has a tank port 14a, a purge port 14b, and an atmospheric port 14c. The tank port 14a is connected to the upper end of the fuel tank FT. As a result, the evaporated fuel in the fuel tank FT flows into the canister 14. The activated carbon 14d adsorbs evaporated fuel from the gas flowing from the fuel tank FT into the case 14e. Thereby, it is possible to prevent the evaporated fuel from being released into the atmosphere.

  The atmospheric port 14 c communicates with the gas pipe 20. The gas pipe 20 is an example of an atmospheric passage. An air cutoff valve 28 and an air filter AF are disposed on the gas pipe 20. The air cutoff valve 28 is an example of a second valve. The air shut-off valve 28 is disposed downstream of the air filter AF (at the air port 14c side). The atmosphere port 14c communicates with the atmosphere via the air filter AF. The air filter AF removes foreign matter from the air flowing into the canister 14 through the atmospheric port 14c. A pressure gauge 36 is provided downstream (at the atmospheric port 14c side) from the atmospheric cutoff valve 28. The pressure gauge 36 is a type that detects a gauge pressure. Note that the pressure gauge 36 only needs to be provided between the pump 12 and the atmospheric cutoff valve 28, and may be provided between the pump 12 and the purge port 14b, for example. The gas pipe 20 is made of a flexible material such as rubber or resin. Further, as the pressure gauge 36, a type that detects absolute pressure may be used.

  The purge port 14 b communicates with the gas pipe 32. The gas pipe 32 includes a first hose 22 and a second hose 26. The first hose 22 connects the canister 14 and the pump 12, and the second hose 26 connects the pump 12 and the intake pipe IP. The second hose 26 (gas pipe 32) is connected to the intake pipe IP upstream from the supercharger CH. That is, the second hose 26 is connected to the atmospheric pressure part 56. A pressure gauge 38 is provided on the second hose. The pressure gauge 38 is provided between the pump 12 and the purge control valve 34. The pressure gauge 38 is a type that detects a gauge pressure. The first and second hoses 22 and 26 are made of a flexible material such as rubber or resin. Moreover, as the pressure gauge 38, the type which detects an absolute pressure can also be used.

  The purge gas in the canister 14 flows from the canister 14 into the first hose 22 through the purge port 14b. The purge gas in the first hose 22 is supplied into the intake pipe IP (atmospheric pressure portion 56) on the upstream side of the supercharger CH via the pump 12, the purge control valve 34, and the second hose 26.

  The pump 12 is disposed between the canister 14 and the intake pipe IP. The pump 12 is a so-called vortex pump (also called a cascade pump or a Wesco pump) or a centrifugal pump. The pump 12 is controlled by the ECU 100. The suction port of the pump 12 communicates with the canister 14 via the first hose 22.

  The discharge port of the pump 12 is connected to the second hose 26. A purge control valve 34 is provided on the second hose 26. The second hose 26 is connected to the intake pipe IP. The pump 12 can be switched between forward and reverse rotation. That is, when the pump 12 is driven in the forward rotation, the gas moves from the suction port of the pump 12 toward the discharge port, and when the pump 12 is driven in the reverse rotation, the gas moves from the discharge port of the pump 12 toward the suction port. To do.

  A purge control valve 34 is arranged on the second hose 26. When the purge control valve 34 is closed, the purge gas is stopped by the purge control valve 34 and does not flow to the second hose 26. On the other hand, when the purge control valve 34 is opened, the purge gas passes through the second hose 26 and flows into the intake pipe IP. If the pump 12 is driven in reverse rotation while the purge control valve 34 is open, the gas in the intake pipe IP flows into the second hose 26 (gas pipe 32). The purge control valve 34 is an electronic control valve and is controlled by the ECU 100.

  The ECU 100 includes a control unit 102 that controls the evaporated fuel processing apparatus 10. The control unit 102 is disposed integrally with another part of the ECU 100 (for example, a part that controls the engine EN). Control unit 102 may be arranged separately from other parts of ECU 100. The control unit 102 includes a CPU and a memory such as a ROM and a RAM. The control unit 102 controls the fuel vapor processing apparatus 10 according to a program stored in advance in the memory. Specifically, the control unit 102 outputs a signal to the pump 12 to control the pump 12. The control unit 102 operates the throttle valve TV, outputs a signal to the purge control valve 34, and executes duty control. The control unit 102 adjusts the valve opening time of the purge control valve 34 by adjusting the duty ratio of the signal output to the purge control valve 34. Further, the control unit 102 outputs a signal to the atmospheric shutoff valve 28 to control the opening and closing of the gas pipe 20.

  Hereinafter, a method of determining the state of the gas pipe 32 (determining whether the second hose 26 is clogged) will be described. 2 and 3 relate to a method of determining the state of the gas pipe 32 by driving the pump 12 in the normal rotation (first determination method). 4 and 5 relate to a method of determining the state of the gas pipe 32 by driving the pump 12 in the reverse rotation (second determination method). In the first and second determination methods, the graphs (FIGS. 2 and 4) show that the purge control valve 34 is in an open state (fully open), the atmospheric shutoff valve 28 is in a closed state (fully closed), and the pump 12 The change of the detected value of the pressure gauges 36 and 38 after starting a drive is shown. The horizontal axis indicates time, and the vertical axis indicates pressure. A curve 36a indicates a detected value of the pressure gauge 36 when the second hose 26 is not clogged (normal state), and a curve 36b indicates the pressure gauge 36 when the second hose 26 is clogged (abnormal state). The detected value is shown. A curve 38b indicates the detected value of the pressure gauge 38 when the second hose 26 is clogged. When the second hose 26 is not clogged (normal state), the second hose 26 and the intake pipe IP (atmospheric pressure part 56) communicate with each other, and therefore the detected value of the pressure gauge 38 is the atmospheric pressure P0. It remains unchanged. In each determination method, the purge control valve 34, the atmospheric shut-off valve 28 and the pump 12 are driven, the detection values of the pressure gauge 36 and the pressure gauge 38 are read, and the state of the second hose 26 is determined. It is executed by the control unit 102) of the ECU 100.

(First determination method)
As shown in FIG. 2, when the pump 12 is driven in the forward rotation, the pressure upstream of the pump 12 (hereinafter referred to as pressure P1) decreases from the atmospheric pressure P0 to become negative pressure (curves 36a and 36b). On the other hand, the pressure downstream of the pump (hereinafter referred to as pressure P2) remains at the atmospheric pressure P0 when the second hose 26 is not clogged, but the atmospheric pressure when the second hose 26 is clogged. The pressure rises from P0 to a positive pressure (curve 38b). The differential pressure (differential pressures 12a and 12b) upstream and downstream of the pump 12 indicates the characteristics (pressure increase characteristics) of the pump 12, and does not change regardless of whether or not the second hose 26 is clogged. That is, the differential pressure 12a and the differential pressure 12b are equal.

  As described above, when the second hose 26 is clogged (abnormal state), the pressure P2 becomes positive. Since the differential pressure 12a and the differential pressure 12b are equal, in the abnormal state, the pressure P1 is higher than that in the case where the second hose 26 is not clogged by the amount that the pressure P2 becomes positive (normal state). The value increases (the amount of decrease in pressure P1 decreases) (curves 36a, 36b). In this determination method, this phenomenon is used to compare the detected value of the pressure gauge 36 (pressure P1 indicated by the curve 36b) with the determination value α1 set based on the pressure P1 in the normal state (curve 36a). To determine whether the state is normal or abnormal. The determination value α1 is set to a value that is larger by the pressure Pα than the pressure P1 in the normal state. The pressure Pα is set to 3 kPa, for example.

  The first determination method will be specifically described with reference to FIG. First, the atmospheric shutoff valve 28 (second valve) is fully closed (step S2), the purge control valve 34 (first valve) is fully opened (step S4), and the pump 12 is driven in the forward rotation (step S6). Although the order of steps S4 to S6 is arbitrary, it is preferable to perform steps S2, 4, and 6 in order from the viewpoint of suppressing introduction of excess purge gas into the intake pipe IP. After the value of the pressure P1 is stabilized, the pressure P1 is compared with the determination value α1 (step S8). When the pressure P1 is greater than or equal to the determination value α1 (step S8: YES), it is determined that the second hose 26 is clogged (abnormal) (step S10). When the pressure P1 is less than the determination value α1 (step S8: NO), it is determined that the second hose 26 is not clogged (normal) (step S12).

  As described above, in the first determination method, the atmospheric shutoff valve 28 is closed, the purge control valve 34 is opened, the pump 12 is driven (forward rotation), and only the pressure P1 of the pressure gauge 36 is detected. It can be determined whether or not the two hose 26 is clogged. That is, in the first determination method, the detected value (pressure P2) of the pressure gauge 38 is not used for determining the presence or absence of clogging. Therefore, in the fuel vapor processing apparatus 10, the pressure gauge 38 is not necessarily required and can be omitted. However, as described above, the pressure increase characteristic of the pump 12 can be calculated by detecting the pressure P2. Therefore, by providing the pressure gauge 38 and detecting the pressure P2 together with the detection of the pressure P1, it is possible to confirm whether or not the characteristics (pressure increase characteristics) of the pump 12 are maintained.

(Second determination method)
As shown in FIG. 4, when the pump 12 is driven in reverse rotation, the pressure P1 upstream of the pump 12 rises from the atmospheric pressure P0 to become a positive pressure (curves 36a and 36b). On the other hand, the pressure P2 downstream of the pump remains at the atmospheric pressure P0 when the second hose 26 is not clogged. However, when the second hose 26 is clogged, the pressure P2 decreases from the atmospheric pressure P0 and becomes negative pressure. (Curve 38b). Even if the pump 12 is driven in reverse rotation, the differential pressure 12a and the differential pressure 12b are equal.

  When the pump 12 is driven in reverse rotation, if the second hose 26 is clogged (abnormal state), the second hose 26 is not clogged to the extent that the pressure P2 becomes negative (normal state). ), The value of the pressure P1 is small (the increase amount of the pressure P1 is small) (curves 36a and 36b). Even when the pump 12 is driven in reverse rotation, this phenomenon is used to make a determination set based on the detected value of the pressure gauge 36 (pressure P1 shown by the curve 36b) and the pressure P1 in the normal state (curve 36a). By comparing with the value α2, it is determined whether the state is normal or abnormal. In this embodiment, the determination value α2 is set to a value smaller than the pressure P1 in the normal state by the pressure Pα. The pressure Pα is set to 3 kPa, for example.

  The second determination method will be specifically described with reference to FIG. First, the atmospheric shutoff valve 28 (second valve) is fully closed (step S22), the purge control valve 34 (first valve) is fully opened (step S24), and the pump 12 is driven in reverse rotation (step S26). The order of steps S24 to S26 is arbitrary, but it is preferable to perform in this order. After the value of the pressure P1 is stabilized, the pressure P1 is compared with the determination value α2 (step S28). In the second determination method, when the pressure P1 is equal to or less than the determination value α2 (step S28: YES), it is determined that the second hose 26 is clogged (abnormal) (step S30). When the pressure P1 exceeds the determination value α2 (step S8: NO), it is determined that the second hose 26 is not clogged (normal) (step S32).

  As described above, even in the second determination method, the atmospheric shutoff valve 28 is closed, the purge control valve 34 is opened, the pump 12 is driven (reverse rotation), and only the pressure P1 of the pressure gauge 36 is detected. It can be determined whether or not the two hose 26 is clogged. Also in the case of determining whether the second hose 26 is clogged by the second determination method, the pressure gauge 38 is not necessarily essential in the evaporated fuel processing apparatus 10, and may be omitted. However, similarly to the first determination method, by detecting the pressure P2, it is possible to calculate the boosting characteristic of the pump 12 and confirm whether or not the characteristic (boosting characteristic) of the pump 12 is maintained.

  As mentioned above, although embodiment of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

10: evaporated fuel processing device 12: pump 14: canister 20: atmospheric passage 28: second valve 32: purge passage 34: first valve 36: pressure gauge EN: internal combustion engine FT: fuel tank IP: intake pipe

Claims (6)

An intake pipe through which air supplied to the internal combustion engine passes;
A canister that adsorbs the evaporated fuel evaporated in the fuel tank;
A purge passage connecting the intake pipe and the canister;
A first valve that is provided in the purge passage and controls a supply amount of the purge gas to the intake pipe; a pump that is provided in the purge passage between the canister and the first valve and that sends the purge gas into the intake pipe;
An atmospheric passage connected to the canister and having one end open to the atmosphere;
A second valve that is provided in the air passage and controls the opening of the air passage;
A pressure gauge that is provided in a passage between the pump and the second valve and detects a pressure in the passage;
An evaporative fuel processing apparatus. In addition, a supercharger is provided in the intake pipe,
The evaporated fuel processing apparatus according to claim 1, wherein the purge passage is connected to the intake pipe upstream of the supercharger.   Furthermore, the evaporative fuel processing apparatus of Claim 1 or 2 with which the 2nd pressure gauge which detects the pressure in a purge channel | path is provided downstream from the said pump.   The evaporative fuel processing apparatus according to any one of claims 1 to 3, wherein the pump is of a type that can be switched between forward and reverse rotations. A determination method for determining the presence or absence of clogging abnormality in the purge passage in the evaporated fuel processing apparatus according to any one of claims 1 to 4,
The first valve is opened, the second valve is closed, and the pump is driven.
Detecting the pressure P1 in the passage between the pump and the second valve;
A determination method for determining whether or not there is a clogging abnormality in the purge passage by comparing the detected pressure P1 with a determination value based on the pressure P1 when no clogging occurs in the purge passage.   The determination method according to claim 5, wherein when determining whether the purge passage is clogged, the pump sends gas toward the second valve.

Images