Evaporation fuel treatment system, abnormality determination program for evaporation fuel treatment system and abnormality determination method for evaporation fuel treatment system

Abstract

To improve frequency of a determination on presence / absence of an abnormality of a purge valve.SOLUTION: An evaporation fuel treatment system includes a canister, a vapor passage, a purge passage, an outside air passage, a purge valve, a pressure sensor and a determination device. The vapor passage causes evaporation fuel generated in a fuel tank to flow to the canister. The purge passage causes the evaporation fuel to flow from the canister to an intake passage of an internal combustion engine. The outside air passage introduces outside air to the canister. The purge valve is located in the purge passage and opens / closes a flow passage of the purge passage. The pressure sensor detects pressure of a flow passage of the outside air passage. The determination device determines presence / absence of an abnormality on the purge valve. The determination device executes first determination control under the requite condition that the internal combustion engine is in operation, and executes second determination control without depending on whether or not the internal combustion engine is in operation (S61-S72).SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an evaporated fuel processing system, an abnormality determination program for an evaporated fuel processing system, and an abnormality determination method for an evaporated fuel processing system. [Background technology]

[0002] The evaporated fuel processing system of Patent Document 1 includes a canister, a vapor passage, a purge passage, an outside air passage, a purge valve, a pressure sensor, and a determination device. The canister adsorbs evaporated fuel. The vapor passage distributes evaporated fuel generated in a fuel tank to the canister. The purge passage distributes evaporated fuel from the canister to an intake passage of an internal combustion engine. The outside air passage introduces outside air into the canister. The purge valve is located midway through the purge passage. The purge valve opens and closes the flow path of the purge passage. The pressure sensor detects the pressure on the canister side relative to the purge valve in the purge passage.

[0003] The determination device determines whether or not an abnormality occurs in the purge valve, that is, the purge valve is stuck in an open state. Specifically, the determination device acquires, as a reference value, a detection value of the pressure sensor when a predetermined first measurement condition is satisfied before the internal combustion engine is operated. This first measurement condition is satisfied when all of various requirements, such as the purge valve being controlled to a closed state, are satisfied. Thereafter, the determination device acquires, as a judgment value, a detection value of the pressure sensor when a predetermined second measurement condition is satisfied after the internal combustion engine is operated. This second measurement condition is satisfied when all of various requirements, such as the purge valve being controlled to a closed state and within a predetermined period of time after the reference value is acquired, are satisfied. Then, the determination device determines that an abnormality occurs in the purge valve, that is, the purge valve is stuck in an open state, when the difference between the reference value and the judgment value is equal to or greater than a predetermined value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-113744 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the evaporated fuel processing system of Patent Document 1, the determination of the presence or absence of an abnormality in the purge valve is not performed unless the internal combustion engine changes from a non-operating state to an operating state and various requirements are satisfied within a certain period of time after the internal combustion engine starts operating. Therefore, in the evaporated fuel processing system of Patent Document 1, the frequency of determination of the presence or absence of an abnormality in the purge valve may decrease depending on the operating conditions of the internal combustion engine. [Means for solving the problem]

[0006] The above-mentioned problem is solved by an evaporated fuel processing system that includes a canister that adsorbs evaporated fuel, a vapor passage that distributes evaporated fuel generated in a fuel tank to the canister, a purge passage that distributes evaporated fuel from the canister to an intake passage of an internal combustion engine, an outside air passage that introduces outside air into the canister, a purge valve that is located in the purge passage and opens and closes a flow path of the purge passage, a pressure sensor that detects the pressure of the flow path of the outside air passage, and a determination device that determines whether or not there is an abnormality related to the purge valve, wherein the determination device performs a first process of storing a first detection value that is a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating, and The control system executes a second process after the first process, which acquires a second detection value, which is the detection value of the pressure sensor when the internal combustion engine is operating and the purge valve is controlled to an open state; a third process after the second process, which determines whether the second detection value is equal to or less than a predetermined specified value; a fourth process, if it is determined in the third process that the second detection value is higher than the specified value, which acquires a third detection value, which is the detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating; and a fifth process, if the absolute value of the difference between the first detection value and the third detection value is equal to or less than a predetermined reference value, which determines that the purge valve is abnormal.

[0007] The abnormality determination program for an evaporated fuel processing system for solving the above-mentioned problems is targeted at an evaporated fuel processing system including a canister for adsorbing evaporated fuel, a vapor passage for circulating evaporated fuel generated in a fuel tank to the canister, a purge passage for circulating evaporated fuel from the canister to an intake passage of an internal combustion engine, an outside air passage for introducing outside air into the canister, a purge valve located in the purge passage for opening and closing a flow path of the purge passage, a pressure sensor for detecting a pressure in a flow path of the outside air passage, and a determination device for determining the presence or absence of an abnormality related to the purge valve, and includes a first detection value stored in the determination device, the first detection value being a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating or not. a second process, after the first process, for acquiring a second detection value which is the detection value of the pressure sensor when the internal combustion engine is operating and the purge valve is controlled to an open state; a third process, after the second process, for determining whether or not the second detection value is equal to or less than a predetermined specified value; a fourth process, if it is determined in the third process that the second detection value is higher than the specified value, for acquiring a third detection value which is the detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating; and a fifth process, after the fourth process, for determining that the purge valve is abnormal if an absolute value of a difference between the first detection value and the third detection value is equal to or less than a predetermined reference value.

[0008] The method for determining an abnormality in an evaporated fuel processing system for solving the above problem is directed to an evaporated fuel processing system including a canister for adsorbing evaporated fuel, a vapor passage for circulating evaporated fuel generated in a fuel tank to the canister, a purge passage for circulating evaporated fuel from the canister to an intake passage of an internal combustion engine, an outside air passage for introducing outside air into the canister, a purge valve located in the purge passage for opening and closing a flow path of the purge passage, a pressure sensor for detecting a pressure in a flow path of the outside air passage, and a determination device for determining the presence or absence of an abnormality related to the purge valve, and the determination device includes a first process for storing a first detection value that is a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating or not. a second process, subsequent to the first process, of acquiring a second detection value which is a detection value of the pressure sensor when the internal combustion engine is operating and the purge valve is controlled to an open state; a third process, subsequent to the second process, of determining whether or not the second detection value is equal to or less than a predetermined specified value; a fourth process, if it is determined in the third process that the second detection value is higher than the specified value, of acquiring a third detection value which is a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating; and a fifth process, subsequent to the fourth process, of determining that the purge valve is abnormal if an absolute value of a difference between the first detection value and the third detection value is equal to or less than a predetermined reference value. Effect of the Invention

[0009] According to the above configuration, for example, the first process to the fifth process are executed even if the operation of the internal combustion engine continues or the operation of the internal combustion engine stops after the third process. This makes it possible to improve the frequency of determination of the presence or absence of an abnormality in the purge valve compared to a configuration in which the presence or absence of an abnormality in the purge valve is determined only when the internal combustion engine changes from a non-operating state to an operating state. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a schematic diagram of a vehicle. [Diagram 2] FIG. 2 is a schematic diagram showing the pump module when the switching valve is in the OFF state. [Diagram 3] FIG. 3 is a schematic diagram showing the pump module when the switching valve is in the ON state. [Figure 4] FIG. 4 is a flowchart showing the first determination control. [Diagram 5] FIG. 5 is a flowchart showing the second determination control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Vehicle Overview> An embodiment of the present invention will be described below with reference to Figures 1 to 5. First, a schematic configuration of a vehicle 100 to which an evaporated fuel processing system is applied will be described. In the following description, when the terms "upstream" and "downstream" are used simply, they refer to upstream and downstream in the flow direction of intake air, exhaust air, evaporated fuel, and outside air.

[0012] As shown in FIG. 1, the vehicle 100 includes an internal combustion engine E. The internal combustion engine E includes an intake passage 11, a plurality of cylinders 12, and an exhaust passage 13. The cylinders 12 are spaces for burning a mixture of intake air and fuel. In this embodiment, the internal combustion engine E includes four cylinders 12. The intake passage 11 introduces intake air from the outside of the internal combustion engine E into the cylinders 12. The downstream end of the intake passage 11 is connected to each cylinder 12. The intake passage 11 includes an upstream intake passage 11A, a surge tank 11B, and a downstream intake passage 11C. The upstream intake passage 11A, the surge tank 11B, and the downstream intake passage 11C are arranged in the above order from the upstream. The surge tank 11B has a function of suppressing intake pulsation and the like. The exhaust passage 13 discharges exhaust gas from the cylinders 12 to the outside of the internal combustion engine E. The upstream end of the exhaust passage 13 is connected to each of the cylinders 12 .

[0013] The internal combustion engine E includes a throttle valve 21, a plurality of fuel injection valves 22, and a fuel tank 31. The throttle valve 21 is located in the upstream intake passage 11A. The throttle valve 21 adjusts the amount of intake air flowing through the upstream intake passage 11A. The fuel injection valve 22 is located near the downstream end of the downstream intake passage 11C. The fuel injection valve 22 injects fuel supplied from the fuel tank 31 into the downstream intake passage 11C. In this embodiment, the internal combustion engine E includes four fuel injection valves 22 corresponding to the four cylinders 12. The fuel tank 31 stores fuel to be supplied to the fuel injection valves 22. The fuel in the fuel tank 31 is supplied to the fuel injection valves 22 through a fuel pipe by being pressure-fed by a feed pump (not shown).

[0014] The internal combustion engine E is equipped with an evaporated fuel processing device 50. The evaporated fuel processing device 50 is a device for suppressing the evaporated fuel generated in the fuel tank 31 from being discharged to the outside of the internal combustion engine E.

[0015] The evaporated fuel processing device 50 includes a vapor passage 51, a canister 52, an outside air passage 53, and a purge passage 55. The evaporated fuel processing device 50 also includes a check valve 61, a purge valve 65, and a pump module .

[0016] The canister 52 adsorbs evaporated fuel generated in the fuel tank 31. A first end of the vapor passage 51 is connected to the canister 52. A second end of the vapor passage 51 is located inside the fuel tank 31. That is, the vapor passage 51 distributes evaporated fuel generated in the fuel tank 31 to the canister 52. The check valve 61 is located midway through the vapor passage 51. The check valve 61 prevents evaporated fuel from flowing from a portion of the vapor passage 51 on the canister 52 side with respect to the check valve 61 to a portion of the vapor passage 51 on the fuel tank 31 side with respect to the check valve 61.

[0017] A first end of the purge passage 55 is connected to the canister 52. A second end of the purge passage 55 is connected to the surge tank 11B of the intake passage 11. That is, the purge passage 55 distributes evaporated fuel from the canister 52 to the surge tank 11B of the intake passage 11. The purge valve 65 is located midway through the purge passage 55. The purge valve 65 opens and closes the flow path of the purge passage 55. In this embodiment, the purge valve 65 is a normally closed type solenoid valve.

[0018] A first end of the outside air passage 53 is connected to the canister 52. A second end of the outside air passage 53 is connected to the outside of the vehicle 100. That is, the outside air passage 53 introduces outside air, which is air outside the vehicle 100, into the canister 52.

[0019] The pump module 70 is located midway through the outside air passage 53. The pump module 70 is a device for determining the presence or absence of gas leakage from the canister 52. Hereinafter, a portion of the outside air passage 53 on the canister 52 side with respect to the pump module 70 will be referred to as a downstream outside air passage 53B, and a portion of the outside air passage 53 on the opposite side to the downstream outside air passage 53B with respect to the pump module 70 will be referred to as an upstream outside air passage 53A.

[0020] 2, the pump module 70 includes a first passage 71, a second passage 72, an upstream shared passage 73, a downstream shared passage 74, and a bypass passage 75. The pump module 70 also includes a pump 76, a pressure sensor 77, and a switching valve 79.

[0021] A first end of the upstream shared passage 73 is connected to the upstream outside air passage 53A. A second end of the upstream shared passage 73 is connected to a first end of the first passage 71. A second end of the first passage 71 is connected to a switching valve 79. A first end of the downstream shared passage 74 is connected to the switching valve 79. A second end of the downstream shared passage 74 is connected to the downstream outside air passage 53B. A first end of the second passage 72 is connected to a connection portion of the first passage 71 and the upstream shared passage 73. A second end of the second passage 72 is connected to the switching valve 79. Therefore, the switching valve 79 is located at the connection portion of the first passage 71, the second passage 72, and the downstream shared passage 74.

[0022] The switching valve 79 is an electromagnetic valve for switching the communication state of the first passage 71, the second passage 72, and the downstream shared passage 74. As shown in FIG. 2, when the switching valve 79 is in the OFF state, the switching valve 79 connects the first passage 71 and the downstream shared passage 74. When the switching valve 79 is in the OFF state, the switching valve 79 does not connect the second passage 72 and the downstream shared passage 74. On the other hand, as shown in FIG. 3, when the switching valve 79 is in the ON state, the switching valve 79 connects the second passage 72 and the downstream shared passage 74. When the switching valve 79 is in the ON state, the switching valve 79 does not connect the first passage 71 and the downstream shared passage 74.

[0023] 2, the bypass passage 75 connects the second passage 72 and the downstream shared passage 74, bypassing the switching valve 79. An intermediate portion of the bypass passage 75 serves as an orifice 75A. The flow path cross-sectional area of ​​the orifice 75A is smaller than the flow path cross-sectional area of ​​the bypass passage 75 other than the orifice 75A. The orifice 75A is used to determine the presence or absence of gas leakage from the canister 52 described above.

[0024] The pump 76 is located on the upstream shared passage 73 side of the connection portion of the second passage 72 with the bypass passage 75. When the pump 76 is in the ON state, the pump 76 sucks gas from the portion of the second passage 72 on the switching valve 79 side with respect to the pump 76, and discharges it to the upstream shared passage 73 side with respect to the pump 76 in the second passage 72. The pump 76 is used to determine the presence or absence of gas leakage from the canister 52 described above.

[0025] The pressure sensor 77 is located at the connection portion of the second passage 72 and the bypass passage 75. The pressure sensor 77 detects the passage pressure PR, which is the pressure of the passage at the connection portion of the second passage 72 and the bypass passage 75. As described above, the passage where the pressure sensor 77 is located is connected to the upstream outside air passage 53A via the pump 76 and the upstream shared passage 73. In addition, the passage where the pressure sensor 77 is located is connected to the downstream outside air passage 53B via the bypass passage 75 and the downstream shared passage 74. Therefore, the pressure sensor 77 can detect the pressure of the passage of the outside air passage 53. In this embodiment, the pressure sensor 77 is a so-called absolute pressure sensor.

[0026] As shown in FIG. 1, the vehicle 100 includes a control device 90. In this embodiment, the control device 90 and the evaporated fuel processing device 50 constitute an evaporated fuel processing system. The control device 90 acquires signals indicating various values ​​from various sensors including the pressure sensor 77. The control device 90 includes an execution unit 91 and a storage unit 92. The storage unit 92 includes a read-only ROM, a readable and writable volatile RAM, and a readable and writable non-volatile storage. The storage unit 92 stores information acquired by the control device 90. The storage unit 92 also stores various programs and various data in advance. The storage unit 92 stores a control program 92A in advance as one of the various programs. An example of the execution unit 91 is a CPU. The execution unit 91 reads the control program 92A from the storage unit 92 to realize various processes described later. In other words, the execution unit 91 also realizes various processes related to an abnormality determination method for the evaporated fuel processing system by reading the control program 92A from the storage unit 92. That is, in this embodiment, the control device 90 is an example of a determination device. Also, the control program 92A is an example of an abnormality determination program.

[0027] The execution unit 91 of the control device 90 executes the purge process when a predetermined purge condition is satisfied. For example, the execution unit 91 of the control device 90 determines that the purge condition is satisfied when the internal combustion engine E is operating and the amount of evaporated fuel adsorbed inside the canister 52 is relatively large. Then, in the purge process, the execution unit 91 controls the purge valve 65 to an open state by outputting a control signal to the purge valve 65. Also, the execution unit 91 controls the switching valve 79 to an OFF state by outputting a control signal to the switching valve 79. Incidentally, the execution unit 91 controls the pump 76 to an OFF state by outputting a control signal to the pump 76. As a result, in the purge process, outside air is introduced into the canister 52 through the outside air passage 53 by the negative pressure of the surge tank 11B of the intake passage 11. Then, the evaporated fuel adsorbed inside the canister 52 and the outside air are introduced into the surge tank 11B of the intake passage 11 through the purge passage 55.

[0028] The execution unit 91 of the control device 90 stores the flow passage pressure PR acquired from the pressure sensor 77 in the storage unit 92 at each predetermined control cycle. The execution unit 91 performs the above process without being conditioned on whether the internal combustion engine E is operating or not. Here, the process of storing the flow passage pressure PR in the storage unit 92 before the first determination process described later and when the purge valve 65 is controlled to the closed state corresponds to the first process. When the purge valve 65 is controlled to the closed state, the negative pressure of the intake passage 11 does not reach the outside air passage 53. Therefore, when the purge valve 65 is controlled to the closed state, the flow passage pressure PR corresponds to the atmospheric pressure at the point where the vehicle 100 is located.

[0029] <First judgment control> Next, the first determination control executed by the control device 90 will be described with reference to FIG. 4. The first determination control is the first control related to the determination of whether or not an abnormality occurs in which the purge valve 65 is stuck in a closed state. The control device 90 starts the first determination control when a predetermined execution condition is satisfied. In this embodiment, the control device 90 starts the first determination control when the internal combustion engine E is operating, the purge process is being executed, the determination completion flag FA is OFF, and the execution flag FB is OFF. In other words, the control device 90 starts the first determination control under the prerequisite that the internal combustion engine E is operating and the purge valve 65 is controlled to an open state. The determination completion flag FA indicates whether or not the determination of the presence or absence of an abnormality regarding the purge valve 65 has been completed. In this embodiment, the determination completion flag FA is OFF at the time when the system of the vehicle 100 is started by operating a start switch (not shown). The execution flag FB is a flag for executing a second determination control (described later). In this embodiment, when the system of the vehicle 100 is started by operating a start switch (not shown), the execution flag FB is OFF.

[0030] As shown in Fig. 4, when the execution unit 91 of the control device 90 starts the first judgment control, it executes the process of step S11. In step S11, the execution unit 91 acquires the flow path pressure PR at the time of the process of step S11 as the first judgment pressure P1. As described above, the flow path pressure PR at this time is the pressure when the internal combustion engine E is operating and the purge valve 65 is controlled to be in an open state. After step S11, the execution unit 91 advances the process to step S12.

[0031] In step S12, the execution unit 91 judges whether the first judgment pressure P1 is equal to or less than a first specified value A1 that is determined in advance. Here, the first specified value A1 is determined, for example, as follows. First, when the purge valve 65 is normal, if the purge valve 65 is controlled to be in an open state and the switching valve 79 is controlled to be in an OFF state, outside air is introduced into the upstream outside air passage 53A. Then, most of the outside air in the upstream outside air passage 53A is introduced into the intake passage 11 via the upstream shared passage 73, the first passage 71, the switching valve 79, and the downstream shared passage 74. At this time, due to the negative pressure in the intake passage 11, the pressure in the flow paths of the upstream shared passage 73, the first passage 71, and the downstream shared passage 74 becomes relatively low, and the flow path pressure PR detected by the pressure sensor 77 also becomes relatively low. Therefore, the first specified value A1 is set as a value that is a certain value higher than the flow path pressure PR that should be detected by the pressure sensor 77 when the purge valve 65 is controlled to the open state and the switching valve 79 is controlled to the OFF state, and is lower than the standard atmospheric pressure. In this embodiment, when attention is paid to the processes of steps S11 and S12, the process of step S11 is the second process. Moreover, the process of step S12 is the third process that follows the second process. Furthermore, the first judgment pressure P1 is the second detection value.

[0032] In step S12, when the execution unit 91 determines that the first determination pressure P1 is higher than the first specified value A1 (S12: NO), the execution unit 91 advances the process to step S21. In step S21, the execution unit 91 controls the switching valve 79 to be in the ON state by outputting a control signal to the switching valve 79. After step S21, the execution unit 91 advances the process to step S22.

[0033] In step S22, the execution unit 91 acquires the channel pressure PR at the time of the processing of step S22 as the second determination pressure P2. After step S22, the execution unit 91 advances the processing to step S23.

[0034] In step S23, the execution unit 91 judges whether the second judgment pressure P2 is equal to or less than a second specified value A2 that is determined in advance. Here, the second specified value A2 is determined, for example, as follows. First, when the purge valve 65 is normal, if the purge valve 65 is controlled to be in an open state and the switching valve 79 is controlled to be in an ON state, outside air is introduced into the upstream outside air passage 53A. Then, most of the outside air in the upstream outside air passage 53A is introduced into the intake passage 11 via the upstream shared passage 73, the second passage 72, the switching valve 79, and the downstream shared passage 74. At this time, since the outside air flows through the pump 76 in the second passage 72, the pressure of the part of the second passage 72 on the switching valve 79 side with respect to the pump 76, i.e., the flow passage pressure PR detected by the pressure sensor 77, becomes correspondingly low. Therefore, the second specified value A2 is set to a value that is a certain value higher than the flow path pressure PR that should be detected by the pressure sensor 77 when the purge valve 65 is controlled to an open state and the switching valve 79 is controlled to an ON state, and is lower than the standard atmospheric pressure. The second specified value A2 is a value lower than the first specified value A1. In this embodiment, when attention is paid to the processes of steps S22 and S23, the process of step S22 is the second process. Moreover, the process of step S23 is the third process that follows the second process. Furthermore, the second judgment pressure P2 is the second detection value.

[0035] In step S23, if the execution unit 91 determines that the second determination pressure P2 is equal to or less than the second specified value A2 (S23: YES), the execution unit 91 advances the process to step S31. In addition, in the above-mentioned step S12, if the execution unit 91 determines that the first determination pressure P1 is equal to or less than the first specified value A1 (S12: YES), the execution unit 91 advances the process to step S31.

[0036] In step S31, the execution unit 91 determines that the purge valve 65 is normal. Next, the execution unit 91 sets the determination completion flag FA to ON. When the determination completion flag FA is set to ON as described above, the determination completion flag FA remains ON until the system of the vehicle 100 is stopped and then started up. After step S31, the execution unit 91 ends the current first determination control.

[0037] On the other hand, in the above-mentioned step S23, when the execution unit 91 determines that the second determination pressure P2 is higher than the second specified value A2 (S23: NO), the execution unit 91 advances the process to step S41. In other words, when the second detection value is higher than a predetermined specified value in the third process, the execution unit 91 advances the process to step S41.

[0038] In step S41, the execution unit 91 sets the execution flag FB to ON. As described above, the execution flag FB is a flag for executing the second determination control, which will be described later. After step S41, the execution unit 91 ends the current first determination control.

[0039] <Second judgment control> Next, the second determination control executed by the control device 90 will be described with reference to Fig. 5. The second determination control is a second control related to the determination of whether or not an abnormality occurs in which the purge valve 65 is stuck in a closed state. In this embodiment, the control device 90 starts the second determination control when the execution flag FB is ON. That is, the control device 90 executes the second determination control without being conditional on whether or not the internal combustion engine E is operating.

[0040] 5, when the execution unit 91 of the control device 90 starts the second determination control, it executes the process of step S61. In step S61, the execution unit 91 controls the purge valve 65 to a closed state by outputting a control signal to the purge valve 65. After step S61, the execution unit 91 advances the process to step S62.

[0041] In step S62, the execution unit 91 acquires the flow path pressure PR stored in the memory unit 92 immediately before the start of the first determination control, specifically, at a time point a predetermined control cycle before the start of the first determination control, as the start pressure PS. In other words, the start pressure PS is the flow path pressure PR before the second process and when the purge valve 65 is controlled to be in the closed state. As described above, the flow path pressure PR detected by the pressure sensor 77 in a situation in which the purge valve 65 is controlled to be in the closed state corresponds to the atmospheric pressure at the point where the vehicle 100 is located. That is, the start pressure PS corresponds to the atmospheric pressure at the point where the vehicle 100 is located immediately before the second process. In this embodiment, the start pressure PS is the first detection value. After step S62, the execution unit 91 advances the process to step S63.

[0042] In step S63, the execution unit 91 acquires the flow path pressure PR at the time of the processing of step S63 as the end pressure PF. In other words, the end pressure PF is the flow path pressure PR after the third processing and when the purge valve 65 is controlled to the closed state. As described above, the flow path pressure PR detected by the pressure sensor 77 in a situation where the purge valve 65 is controlled to the closed state corresponds to the atmospheric pressure at the point where the vehicle 100 is located. That is, the end pressure PF corresponds to the atmospheric pressure at the point where the vehicle 100 is located immediately after the third processing. In this embodiment, the processing of step S63 is the fourth processing. Moreover, the end pressure PF is the third detection value. After step S63, the execution unit 91 advances the processing to step S64.

[0043] In step S64, the execution unit 91 determines whether or not the absolute value of the difference between the start pressure PS and the end pressure PF is greater than a predetermined reference value B. In other words, the execution unit 91 determines whether or not the atmospheric pressure at the point where the vehicle 100 is located has changed from when the flow path pressure PR used as the start pressure PS is detected until when the flow path pressure PR used as the end pressure PF is detected. Here, the reference value B is a threshold value for determining whether or not the change in atmospheric pressure from when the flow path pressure PR used as the start pressure PS is detected until when the flow path pressure PR used as the end pressure PF is detected is within an allowable range.

[0044] In step S64, when the execution unit 91 determines that the absolute value of the difference between the start pressure PS and the end pressure PF is greater than the reference value B (S64: YES), the execution unit 91 advances the process to step S71. In other words, when the execution unit 91 determines that the change in atmospheric pressure from when the flow path pressure PR used as the start pressure PS is detected to when the flow path pressure PR used as the end pressure PF is detected is unacceptably large, the execution unit 91 advances the process to step S71.

[0045] In step S71, the execution unit 91 reserves the determination regarding the purge valve 65. Then, the execution unit 91 sets the execution flag FB to OFF. After step S71, the execution unit 91 ends the current second determination control.

[0046] On the other hand, if the execution unit 91 determines in step S64 that the absolute value of the difference between the start pressure PS and the end pressure PF is equal to or less than the reference value B (S64: NO), the execution unit 91 advances the process to step S72. In other words, if the execution unit 91 determines that the change in atmospheric pressure from when the flow path pressure PR used as the start pressure PS is detected to when the flow path pressure PR used as the end pressure PF is detected is acceptably small, the execution unit 91 advances the process to step S72.

[0047] In step S72, the execution unit 91 determines that the purge valve 65 is abnormal. Then, the execution unit 91 outputs a control signal to a display (not shown) to notify the driver of the vehicle 100, etc., on the display that the purge valve 65 is abnormal. Next, the execution unit 91 sets the determination completion flag FA to ON. In this embodiment, the processing of steps S64 and S72 is the fifth processing. After step S72, the execution unit 91 ends this second determination control.

[0048] <Action of this embodiment> Suppose that an abnormality occurs in the vehicle 100, in which the purge valve 65 is stuck in a closed state. Then, suppose that the control device 90 executes the first determination control. In this case, even if the purge valve 65 is controlled to an open state, the purge valve 65 remains in a closed state. Therefore, the passage pressure PR detected by the pressure sensor 77 becomes high due to the purge valve 65 being in a closed state, and the first determination pressure P1 and the second determination pressure P2 become relatively high. Then, the control device 90 makes a negative determination in step S12 and also makes a negative determination in step S23. Then, in the second determination control, if the change in the atmospheric pressure from when the passage pressure PR used as the start pressure PS is detected to when the passage pressure PR used as the end pressure PF is detected is small enough to be tolerated, the control device 90 makes a negative determination in step S64. As a result, in step S72, the control device 90 determines that the purge valve 65 is abnormal.

[0049] <Effects of this embodiment> (1) In this embodiment, the control device 90 executes the first determination control with the condition that the internal combustion engine E is operating, while executing the second determination control without the condition that the internal combustion engine E is operating. Therefore, for example, even if the operation of the internal combustion engine E continues or the operation of the internal combustion engine E stops after the first determination control, the first determination control and the second determination control are executed. In other words, for example, even if the operation of the internal combustion engine E continues or the operation of the internal combustion engine E stops after the third process, the first process to the fifth process are executed. This can improve the frequency of determining whether or not there is an abnormality regarding the purge valve 65, compared to a configuration in which the determination of whether or not there is an abnormality regarding the purge valve 65 is executed only when, for example, the internal combustion engine E changes from a non-operating state to an operating state.

[0050] In this embodiment, if the purge valve 65 is normal, the first judgment pressure P1 and the second judgment pressure P2 are relatively low when the internal combustion engine E is operating and the purge valve 65 is controlled to the open state. Here, it is assumed that the absolute value of the difference between the start pressure PS and the end pressure PF is equal to or less than the reference value B. In this situation, it is presumed that the atmospheric pressure at the point where the vehicle 100 is located has not changed significantly from when the flow path pressure PR used as the start pressure PS is detected until when the flow path pressure PR used as the end pressure PF is detected. Therefore, it is unlikely that the first judgment pressure P1 and the second judgment pressure P2 have changed due to a change in atmospheric pressure. And, for example, in a situation where the first judgment pressure P1 is determined to be higher than the first specified value A1 and the second judgment pressure P2 is determined to be higher than the second specified value A2, it can be said that the first judgment pressure P1 and the second judgment pressure P2 are relatively high. Therefore, in the above situation, it can be presumed that an abnormality has occurred in which the purge valve 65 is stuck in the closed state.

[0051] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0052] In the above embodiment, the first determination control may be modified. For example, either the processing of steps S11 and S12 or the processing of steps S21 to S23 may be omitted. As a specific example, when the processing of steps S21 to S23 is omitted, if the execution unit 91 determines in step S12 that the first judgment pressure P1 is higher than the first specified value A1 (S12: NO), the execution unit 91 may proceed to the processing of step S41. Furthermore, when the processing of steps S11 and S12 is omitted, the execution unit 91 may execute the processing of step S21 when the first judgment control is started.

[0053] In the above embodiment, the configuration of the vehicle 100 may be changed. For example, the pump module 70 may be omitted. As a specific example, if it is only necessary to determine whether or not an abnormality occurs in which the purge valve 65 is stuck in the closed state, the pump module 70 may be omitted. In this case, it is sufficient that only the pressure sensor 77 is located in the outside air passage 53. [Explanation of symbols]

[0054] E...internal combustion engine 11...intake passage 12...cylinder 13...exhaust passage 21...throttle valve 31...fuel tank 50...evaporative fuel treatment device 51...vapor passage 52...canister 53...external air passage 55...purge passage 61...check valve 65...purge valve 70...pump module 71...first passage 72...second passage 73...upstream shared passage 74...downstream shared passage 75...bypass passage 76...pump 77...pressure sensor 79...switching valve 90...control device 91...execution unit 92...storage unit 92A...control program 100...vehicle

Claims

1. A canister for absorbing evaporated fuel; a vapor passage for passing evaporated fuel generated in a fuel tank to the canister; a purge passage for passing evaporated fuel from the canister to an intake passage of an internal combustion engine; an outside air passage for introducing outside air into the canister; a purge valve located in the purge passage for opening and closing a flow path of the purge passage; a pressure sensor for detecting a pressure in a flow path of the outside air passage; A determination device that determines whether or not there is an abnormality related to the purge valve; A fuel vapor processing system comprising: The determination device includes: a first process for storing a first detection value, which is a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating; a second process for acquiring a second detection value, which is a detection value of the pressure sensor when the internal combustion engine is operating and the purge valve is controlled to be in an open state, after the first process; a third process that is performed after the second process and determines whether the second detection value is equal to or smaller than a predetermined specified value; a fourth process of acquiring a third detection value, which is a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating, when it is determined in the third process that the second detection value is higher than the specified value; a fifth process for determining that the purge valve is abnormal when an absolute value of a difference between the first detection value and the third detection value is equal to or smaller than a predetermined reference value after the fourth process; Run Evaporative fuel processing system.

2. A canister for absorbing evaporated fuel; a vapor passage for passing evaporated fuel generated in a fuel tank to the canister; a purge passage for passing evaporated fuel from the canister to an intake passage of an internal combustion engine; an outside air passage for introducing outside air into the canister; a purge valve located in the purge passage for opening and closing a flow path of the purge passage; a pressure sensor for detecting a pressure in a flow path of the outside air passage; A determination device that determines whether or not there is an abnormality related to the purge valve; The present invention relates to an evaporated fuel processing system comprising: The determination device includes: a first process for storing a first detection value, which is a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating; a second process for acquiring a second detection value, which is a detection value of the pressure sensor when the internal combustion engine is operating and the purge valve is controlled to be in an open state, after the first process; a third process that is performed after the second process and determines whether the second detection value is equal to or smaller than a predetermined specified value; a fourth process of acquiring a third detection value, which is a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating, when it is determined in the third process that the second detection value is higher than the specified value; a fifth process for determining that the purge valve is abnormal when an absolute value of a difference between the first detection value and the third detection value is equal to or smaller than a predetermined reference value after the fourth process; Run A program for determining abnormalities in the fuel vapor processing system.

3. A canister for absorbing evaporated fuel; a vapor passage for passing evaporated fuel generated in a fuel tank to the canister; a purge passage for passing evaporated fuel from the canister to an intake passage of an internal combustion engine; an outside air passage for introducing outside air into the canister; a purge valve located in the purge passage for opening and closing a flow path of the purge passage; a pressure sensor for detecting a pressure in a flow path of the outside air passage; A determination device that determines whether or not there is an abnormality related to the purge valve; The present invention relates to an evaporated fuel processing system comprising: The determination device, a first process for storing a first detection value, which is a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating; a second process for acquiring a second detection value, which is a detection value of the pressure sensor when the internal combustion engine is operating and the purge valve is controlled to be in an open state, after the first process; a third process that is performed after the second process and determines whether the second detection value is equal to or smaller than a predetermined specified value; a fourth process of acquiring a third detection value, which is a detection value of the pressure sensor when the purge valve is controlled to a closed state, regardless of whether the internal combustion engine is operating, when it is determined in the third process that the second detection value is higher than the specified value; a fifth process for determining that the purge valve is abnormal when an absolute value of a difference between the first detection value and the third detection value is equal to or smaller than a predetermined reference value after the fourth process; Run A method for determining an abnormality in an evaporated fuel processing system.

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