WO2016208475A1

WO2016208475A1 - Inspection apparatus and inspection method

Info

Publication number: WO2016208475A1
Application number: PCT/JP2016/067864
Authority: WO
Inventors: 遼佑岸; 加藤　康夫; 長谷川　茂; 伊藤　智啓; 真兼子; 康誠高木
Original assignee: 株式会社デンソー
Priority date: 2015-06-22
Filing date: 2016-06-16
Publication date: 2016-12-29

Abstract

This inspection apparatus is provided with a pressure sensor (21), a reference orifice (22), a pump (20), and switching valves (30, 70). The reference orifice is provided to a first communication channel (27) for ensuring communication between a pressure passage (26) that is provided with the pressure sensor and a tank passage (25) that is in communication with a fuel tank (8). In the pump, either one of an intake port (201) and a discharge port (202) is in communication with an atmosphere passage (24) communicated with the atmosphere, the other is in communication with the pressure passage, and the pressure in the pressure passage can be reduced or increased. The switching valves operate in accordance with the pressure difference between the atmosphere passage and the pressure passage that varies due to the driving of the pump, and are capable of switching between a state in which a second communication channel (28) that opens into the pressure passage is blocked from communicating with passages other than the pressure passage, and the atmosphere passage and the tank passage are in communication with each other, and a state in which communication is blocked between non-atmosphere and the pump in the atmosphere passage, and the second communication channel and the tank passage are in communication with each other.

Description

Inspection apparatus and inspection method

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2015-124922 filed on June 22, 2015 and Japanese Patent Application No. 2016-1111892 filed on June 3, 2016. The description is incorporated.

The present disclosure relates to an inspection apparatus and an inspection method for inspecting evaporative fuel leakage.

2. Description of the Related Art Conventionally, there has been known an inspection apparatus that inspects leakage of evaporated fuel generated in a fuel tank and leakage of evaporated fuel from a canister that collects evaporated fuel generated in the fuel tank.

The inspection apparatus described in Patent Document 1 inspects the leakage of evaporated fuel by the following method. First, when the internal combustion engine is stopped, the pump is operated with the flow path leading to the atmosphere, the flow path leading to the reference orifice, and the flow path leading to the pump in this order, and the flow leading to the reference orifice is performed. The road pressure is detected as a reference pressure. Next, the electromagnetic valve is driven, the flow path leading to the atmosphere is shut off, and switching is performed so that the flow path leading to the pump and the flow path leading to the canister and the tank communicate. Subsequently, the pump is operated to depressurize the fuel tank, and the pressure in the flow path leading to the canister and the tank is detected as the system pressure. Finally, by comparing the reference pressure and the system pressure, it is determined whether or not the evaporative fuel leakage of the canister and the fuel tank is within an allowable range.

JP 2014-152678 A

By the way, the inspection apparatus described in Patent Document 1 uses a solenoid valve to communicate and block the flow path leading to the atmosphere, the flow path leading to the reference orifice, the flow path leading to the pump, and the flow path leading to the canister and the tank. Switching. The drive portion of the electromagnetic valve is composed of a coil, a stator, a mover, and the like. For this reason, the physique of the inspection apparatus is enlarged by the drive part of the electromagnetic valve. In addition, the power consumed by the inspection apparatus may increase due to the driving of the electromagnetic valve.

This disclosure aims to provide an inspection apparatus and an inspection method capable of reducing the size and reducing the power consumption.

The inspection apparatus according to the first aspect of the present disclosure includes a pressure sensor, a reference orifice, a pump, and a switching valve. The reference orifice is provided in the first communication path that connects the pressure path provided with the pressure sensor and the tank path communicating with the fuel tank. One of the suction port and the discharge port communicates with an air passage that communicates with the atmosphere, and the other communicates with a pressure passage, and the pump can depressurize or pressurize the pressure passage. The switching valve operates in accordance with the pressure difference between the pressure passage and the atmospheric passage that changes by driving the pump, blocks communication of the second communication passage leading to the pressure passage to other than the pressure passage, and connects the atmospheric passage and the tank passage. Can be switched between a state in which the second communication passage and the tank passage are communicated with each other, and a state in which communication between the atmosphere passage and the pump and other than the atmosphere is blocked.

Thus, the inspection apparatus can be equipped with a switching valve that operates in accordance with the differential pressure between the pressure passage and the atmospheric passage, thereby eliminating the electromagnetic valve provided in the conventional inspection apparatus. Therefore, the inspection apparatus can be simplified in configuration and downsized. Further, since the inspection device does not use a solenoid valve, it is possible to reduce power consumption.

The inspection method according to the second aspect of the present disclosure includes a first reference pressure detection step, a tank pressure reduction step, a system pressure detection step, and a determination step. In the first reference pressure detecting step, the switching valve shuts off the communication of the second communication passage other than the pressure passage other than the pressure passage, and rotates the pump at a low speed while the air passage and the tank passage are in communication with each other. Is stored as the first reference pressure. In the tank depressurization step, the switching valve is operated by switching the pump from the low speed rotation to the high speed rotation, and the switching valve blocks communication between the pump and the atmosphere other than the atmosphere passage and communicates the second communication passage and the tank passage. Then, depressurize the tank passage. In the system pressure detection process, the pump is rotated at a low speed with the same switching valve as in the tank pressure reduction process, and the pressure detected by the pressure sensor is stored as the system pressure. In the determination step, the first reference pressure is compared with the system pressure, and when the absolute value of the system pressure is smaller than the absolute value of the first reference pressure, or the absolute value of the difference between the system pressure and the first reference pressure is predetermined. When it is smaller than the threshold value, it is determined that the fuel vapor leakage of the fuel tank is larger than the reference value. In the determination step, when the absolute value of the system pressure is larger than the absolute value of the first reference pressure and the absolute value of the difference between the system pressure and the first reference pressure is greater than a predetermined threshold, the evaporated fuel in the fuel tank It is determined that the leak is smaller than the reference value. The absolute value here is an absolute value relative to the relative pressure when the atmospheric pressure is zero.

This allows the evaporative fuel leakage inspection method to operate the switching valve by changing the pump speed. Further, in this inspection method, the inspection can be completed in a short time by rotating the pump at a high speed to decompress the fuel tank and the canister. Therefore, this inspection method can reduce the power consumed for the inspection.

The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. The drawing
It is a schematic diagram showing an intake system of an engine to which the inspection device according to the first embodiment of the present disclosure is applied, It is an enlarged view of the II part of FIG. FIG. 2 is an enlarged view showing a state where a switching valve is operated in a II part of FIG. Is a graph showing the relationship between the switching valve operating pressure and the return pressure, It is a flowchart of the inspection method of the fuel vapor leakage in the inspection device according to the first embodiment of the present disclosure, It is a flowchart of the inspection method of the fuel vapor leakage in the inspection device according to the first embodiment of the present disclosure, It is a time chart of the test | inspection of the fuel vapor leak in the test | inspection apparatus by 1st Embodiment of this indication, It is explanatory drawing in each step | level of the test | inspection of the fuel vapor leak in the test | inspection apparatus by 1st Embodiment of this indication, It is explanatory drawing in each step | level of the test | inspection of the fuel vapor leak in the test | inspection apparatus by 1st Embodiment of this indication, It is a flowchart of the test | inspection method in the test | inspection apparatus by 2nd Embodiment of this indication, It is a flowchart of the test | inspection method in the test | inspection apparatus by 2nd Embodiment of this indication, It is a mimetic diagram of an inspection device by a 3rd embodiment of this indication, It is a schematic diagram of the inspection apparatus by 4th Embodiment of this indication, It is a flowchart of the test | inspection method in the test | inspection apparatus by 4th Embodiment of this indication, It is a time chart of the test | inspection of the fuel vapor leak in the test | inspection apparatus by 4th Embodiment of this indication, It is a schematic diagram of the inspection apparatus by 5th Embodiment of this indication, It is a mimetic diagram of an inspection device by a 6th embodiment of this indication, In FIG. 17, it is a schematic diagram which shows the state which the switching valve act | operated, It is a time chart of the test | inspection of the fuel vapor leak in the test | inspection apparatus by 6th Embodiment of this indication.

Hereinafter, an inspection apparatus and an inspection method according to a plurality of embodiments of the present disclosure will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same configuration is denoted by the same reference numeral, and description thereof is omitted.

(First embodiment)
The inspection apparatus according to the first embodiment of the present disclosure is used for inspection of leakage of evaporated fuel from a fuel tank and a canister.

FIG. 1 schematically shows an engine 2 to which the inspection apparatus 1 of the first embodiment is applied. A throttle valve 4 and an injector 5 are provided in the intake passage 3 for introducing air into the engine 2. The fuel injected from the injector 5 into the intake passage 3 is introduced into the combustion chamber 6 of the engine 2 together with the air flowing through the intake passage 3, burned in the combustion chamber 6, and then discharged to the atmosphere via the exhaust passage 7. .

Evaporated fuel is generated inside the fuel tank 8 in which fuel to be supplied to the injector 5 is stored due to evaporation of the fuel. In order to process the evaporated fuel, the fuel tank 8 and the intake passage 3 communicate with each other through the first purge passage 9, the canister 10 and the second purge passage 11. The evaporated fuel generated in the fuel tank 8 flows through the first purge passage 9 and is adsorbed and held by the adsorbent 12 such as activated carbon that the canister 10 has.

When the purge valve 13 provided in the second purge passage 11 is opened during the operation of the engine 2, the evaporated fuel adsorbed and held in the canister 10 is separated from the adsorbent 12 and is sucked through the second purge passage 11. It is removed in the passage 3.

The inspection device 1 is for inspecting evaporative fuel leakage from the fuel tank 8, the canister 10, the first purge passage 9 and the second purge passage 11 to the outside air.

As shown in FIG. 2, the inspection apparatus 1 includes a pump 20, a pressure sensor 21, a switching valve 30, a reference orifice 22, a ventilation orifice 23, and the like. Further, the inspection apparatus 1 is formed with an atmospheric passage 24, a tank passage 25, a pressure passage 26, a first communication passage 27, a second communication passage 28, and the like.

The atmosphere passage 24 is open to the atmosphere through a filter 29. The atmospheric passage 24 communicates with the atmospheric port 36 of the switching valve 30.

The tank passage 25 communicates with the canister 10. The canister 10 communicates with the fuel tank 8 via the first purge passage 9 described above.

The pump 20 is, for example, a vane pump that sends air from the suction port 201 to the discharge port 202 in accordance with the rotational speed of an impeller (not shown) that is rotated by a motor (not shown).

The pump 20 has a suction port 201 in communication with the pressure passage 26 and a discharge port 202 in communication with the atmospheric passage 24. The pump 20 can depressurize and pressurize the pressure passage 26. The pressure passage 26 communicates with the first communication passage 27, the second communication passage 28, and the pressure introduction port 35 of the switching valve 30.

The pump 20 can also send air from the discharge port 202 to the suction port 201 when the rotation direction of the impeller is reversed. Therefore, the pump 20 can be mounted with the discharge port 202 and the suction port 201 reversed. That is, the discharge port 202 and the suction port 201 are names for convenience.

The pressure sensor 21 provided in the pressure passage 26 detects the atmospheric pressure in the pressure passage 26 and transmits the signal to an electronic control unit (ECU) 50 of the vehicle. The ECU 50 is a computer having a CPU, a RAM, a ROM, an input / output port, and the like. The ECU 50 detects leakage of evaporated fuel from the fuel tank 8 and the like based on a signal input from the pressure sensor 21. The ECU 50 can control the rotational speed of the impeller of the pump 20 by controlling the power supplied to the motor of the pump 20.

The first communication passage 27 communicates the pressure passage 26 and the tank passage 25 without passing through the switching valve 30. A reference orifice 22 is provided in the first communication path 27. The reference orifice 22 is set smaller than the size of the opening in which the fuel vapor leakage in the fuel tank 8 is allowed. For example, the current standards of CARB (California Air Resources Board) and EPA (Environmental Protection Agency: US Department of the Environment) require detection of evaporative fuel leakage from an opening corresponding to φ0.5 mm. In the first embodiment, the cross-sectional area of the reference orifice 22 is set to φ0.25 mm, for example.

The second communication passage 28 communicates the pressure passage 26 and the ventilation port 38 of the switching valve 30. A ventilation orifice 23 is provided in the second communication passage 28. Note that the vent orifice 23 may not be provided in the second communication path 28.

The switching valve 30 is a differential pressure valve that operates in accordance with the differential pressure between the pressure passage 26 and the atmospheric passage 24 that changes as the pump 20 is driven. The switching valve 30 includes a housing 31, a valve member 40, and a spring 41.

The housing 31 has a pressure chamber 32, an atmospheric pressure chamber 33, and a tank pressure chamber 34 formed therein. The housing 31 is provided with a pressure introduction port 35 and an atmospheric port 36.

The pressure introduction port 35 communicates the pressure passage 26 and the pressure chamber 32. The atmospheric port 36 communicates the atmospheric passage 24 and the atmospheric pressure chamber 33. The tank port 37 communicates the tank passage 25 and the tank pressure chamber 34. The ventilation port 38 communicates the second communication passage 28 and the tank pressure chamber 34.

The housing 31 may be composed of a single member or a plurality of members, or a part of the housing 31 may be an atmospheric passage 24, a tank passage 25, a pressure passage 26, or a second communication passage. It may be configured integrally with a member forming 28 or the like. That is, in the first embodiment, the member forming the pressure chamber 32, the atmospheric pressure chamber 33, and the tank pressure chamber 34 is referred to as a housing 31.

The valve member 40 has a diaphragm 42 and a valve body 43.

The diaphragm 42 divides the pressure chamber 32 and the atmospheric pressure chamber 33 and operates by receiving a differential pressure between the pressure chamber 32 and the atmospheric pressure chamber 33. The diaphragm 42 is urged toward the atmospheric pressure chamber 33 by a spring 41 provided in the pressure chamber 32.

The valve body 43 has a connection portion 44 connected to the diaphragm 42 and operates together with the diaphragm 42. As shown in FIG. 2, the valve body 43 can be seated and separated from a first valve seat 381 in which the first seat surface 45 is provided in the ventilation port 38. Further, as shown in FIG. 3, the valve body 43 can be seated on and separated from a second valve seat 331 in which the second seat surface 46 is provided between the tank pressure chamber 34 and the atmospheric pressure chamber 33.

In addition, you may comprise so that the valve body 43 may seat to the 1st valve seat 381 with the elastic force of the diaphragm 42 itself, without providing the spring 41. FIG.

As shown in FIG. 2, when the valve body 43 is seated on the first valve seat 381, communication with the second communication passage 28 other than the pressure passage 26 is blocked, while the atmospheric passage 24 and the tank passage 25 are Communicate. A position when the valve body 43 is seated on the first valve seat 381 is referred to as a first position.

On the other hand, as shown in FIG. 3, when the valve body 43 is seated on the second valve seat 331, the communication to the atmosphere other than the pump 20 and the atmosphere in the atmospheric passage 24 is blocked, while the second communication passage 28 and the tank passage 25. And communicate. A position when the valve body 43 is seated on the second valve seat 331 is referred to as a second position.

The valve element 43 is movable between the first position and the second position.

As shown in FIG. 2, the surface on which the valve body 43 is exposed to the ventilation port 38 side when the valve body 43 is seated on the first valve seat 381 is referred to as a first pressure receiving surface 431. Further, as shown in FIG. 3, a surface where the valve body 43 is exposed to the atmospheric pressure chamber 33 side when the valve body 43 is seated on the second valve seat 331 is referred to as a second pressure receiving surface 432. Here, since the opening area of the second valve seat 331 is smaller than the opening area of the first valve seat 381, the second pressure receiving surface 432 is smaller than the first pressure receiving surface 431. Therefore, when the valve body 43 is in the second position, the force acting on the valve body 43 due to the differential pressure between the tank pressure chamber 34 and the atmospheric pressure chamber 33 is the second ream when the valve body 43 is in the first position. The differential pressure between the passage 28 and the tank pressure chamber 34 is smaller than the force acting on the valve body 43. As described above, the second communication passage 28 communicates with the pressure passage 26. Therefore, the differential pressure between the atmospheric passage 24 and the pressure passage 26 when the valve body 43 moves from the second position to the first position is the atmospheric passage 24 when the valve body 43 moves from the first position to the second position. And a pressure difference smaller than the pressure passage 26.

The differential pressure between the atmospheric passage 24 and the pressure passage 26 when the valve body 43 moves from the first position to the second position is referred to as operating pressure. The differential pressure between the atmospheric passage 24 and the pressure passage 26 when the valve body 43 moves from the first position to the second position is referred to as return pressure.

FIG. 4 shows the relationship between the operating pressure and return pressure of the switching valve 30.

In FIG. 4, the horizontal axis indicates a value smaller than zero. In FIG. 4 and the following description, when referring to the magnitude of the pressure without particular notice, the absolute value of the relative pressure when the atmospheric pressure is 0 is assumed.

4 indicates the characteristics of the pressure of the air passing through only the reference orifice 22 provided in the first communication passage 27 and the flow rate thereof. Hereinafter, this characteristic is referred to as a reference orifice characteristic.

The broken line B in FIG. 4 shows the characteristics of the pressure of the air passing through both the reference orifice 22 provided in the first communication passage 27 and the ventilation orifice 23 provided in the second communication passage 28 and the flow rate thereof. Yes. Hereinafter, this characteristic is referred to as a reference and vent orifice characteristic.

The solid line C in FIG. 4 shows the characteristics of the flow path resistance and the flow rate when the pump 20 is rotated at a low speed.

The broken line D in FIG. 4 shows the characteristics of the flow path resistance and the flow rate when the pump 20 is rotated at a high speed.

The low-speed rotation of the pump 20 is a state where a predetermined current is supplied to the motor of the pump 20 to rotate the impeller of the pump 20, or the motor or impeller of the pump 20 is rotated at a predetermined number of rotations. The state when it is rotated.

The high-speed rotation of the pump 20 is a state in which a predetermined current larger than that at the time of low-speed rotation is supplied to the motor of the pump 20 to rotate the impeller of the pump 20 or a speed that is higher than that at the time of low-speed rotation. The state when the motor of the pump 20 or the impeller is rotated at the number of rotations.

The current value or the number of rotations supplied to the pump 20 can be set as appropriate through experiments. The rotational speed of the pump 20 during high speed rotation is set to a rotational speed at which the fuel tank 8 does not collapse due to deformation or the like when the fuel tank 8 is depressurized by driving the pump 20. In FIG. 4, the pressure at which the fuel tank 8 is crushed by deformation or the like is indicated by a symbol E.

The pressure when the pump 20 rotates at a low speed in the reference orifice characteristic indicated by the solid line A is referred to as a first reference pressure Pref1. A leak determination threshold value set in consideration of an output error of the pressure sensor 21 based on the first reference pressure Pref1 is indicated by a symbol T.

Further, the pressure at the time of high speed rotation of the pump 20 in the reference and vent orifice characteristics shown by the broken line B is referred to as a second reference pressure Pref2. The second reference pressure Pref2 is set to a value smaller than the pressure at which the fuel tank 8 is crushed by deformation or the like when the fuel tank 8 is depressurized by driving the pump 20.

The operating pressure of the valve member 40 is set to be larger than the first reference pressure Pref1 or the leak judgment threshold T and smaller than the second reference pressure Pref2. The return pressure of the valve member 40 is set to be smaller than the first reference pressure Pref1 or the leak judgment threshold T and larger than zero. Thereby, the valve member 40 has a predetermined hysteresis in the operating pressure and the return pressure. That is, when the differential pressure between the atmospheric passage 24 and the pressure passage 26 is larger than the first reference pressure Pref1 or the leak judgment threshold T and smaller than the second reference pressure Pref2, the valve member 40 is moved from the first position to the first position. Move to 2 position. On the other hand, when the differential pressure between the atmospheric passage 24 and the pressure passage 26 is smaller than the first reference pressure Pref1 or the leakage judgment threshold T and larger than 0, the valve member 40 moves from the second position to the first position. To do.

Next, an evaporative fuel leakage inspection method will be described with reference to the flowcharts of FIGS. 5 and 6, the time chart of FIG. 7, and the schematic diagrams and graphs of FIGS.

7 shows the time axis in the evaporative fuel leakage inspection, the middle stage is a graph showing the rotational speed of the pump 20 with the passage of time, and the lower stage shows the detected pressure of the pressure sensor 21 with the passage of time. It is a graph which shows a change. Note that the pump 20 depressurizes the pressure passage 26 during normal rotation. Here too, when referring to the magnitude of the pressure, it means the absolute value.

The inspection for evaporative fuel leakage starts when a predetermined time has elapsed after the operation of the engine 2 is stopped. The predetermined time is set to a time required for the temperature of the vehicle to stabilize.

In S1, the ECU 50 detects the atmospheric pressure P0. This process is performed with the pump 20 stopped before the time t0 to the time t1 in FIG. At that time, the switching valve 30 is in the first position, and the pressure passage 26, the first communication passage 27, and the atmospheric passage 24 communicate with each other. Therefore, the pressure sensor 21 detects the atmospheric pressure P0 and transmits it to the ECU 50. The ECU 50 corrects various parameters used for subsequent processing according to the altitude of the vehicle calculated based on the atmospheric pressure P0.

In S2, the ECU 50 drives the pump 20 at a low speed. In this process, when the pump 20 starts driving at low speed rotation at time t1 in FIG. 7, the pressure detected by the pressure sensor 21 starts to decrease thereafter. At that time, the switching valve 30 shown in FIG. 8A1 is in the first position. In (A1) of FIG. 8, hatching is described in the flow path that is depressurized by driving the pump 20. By driving the pump 20, air flows through the reference orifice 22 of the first communication passage 27 that communicates with the pressure passage 26.

In S3, the ECU 50 determines whether or not a predetermined time has elapsed from the start of driving of the pump 20. The ECU 50 repeats the process of S3 until a predetermined time has elapsed. In this process, the pressure detected by the pressure sensor 21 that has decreased since time t1 in FIG. 7 reaches the first reference pressure Pref1 at time t2. Then, after the time t2, the first reference pressure Pref1 is maintained.

In S3, the ECU 50 determines whether or not the detected pressure of the pressure sensor 21 reaches the predetermined pressure and maintains the predetermined pressure instead of determining whether or not the predetermined time has elapsed. You may perform the process which determines. In that case, the ECU 50 repeats the process of S3 until the detected pressure of the pressure sensor 21 reaches the predetermined pressure.

In S4, the ECU 50 stores the pressure detected by the pressure sensor 21 as the first reference pressure Pref1. This process is performed between time t2 and t3 in FIG. The flow rate characteristic at that time is indicated by a symbol M1 in the graph of FIG.

In S5, the ECU 50 switches the drive of the pump 20 to high speed rotation. In this process, the pump 20 is switched to high speed rotation at time t3 in FIG. At this time, the flow path indicated by hatching in FIG. 8 (B1) is depressurized, and the switching valve 30 starts the switching operation. The flow rate characteristics at that time shift from the symbol M1 shown in the graph of FIG. 8B2 to the direction in which the flow rate and pressure increase along the solid line A (the direction of the solid arrow Ah1 in FIG. 8B2). .

In S6, the switching valve 30 is switched from the first position to the second position. That is, as shown in FIG. 8 (C1), the switching valve 30 is in the second position. By this process, the pressure detected by the pressure sensor 21 decreases after time t4 in FIG. The flow rate characteristic at that time shifts from that indicated by the symbol M1 in the graph of FIG. 8C2 to that indicated by the symbol M3 via the one indicated by the symbol M2.

In S7, the detected pressure of the pressure sensor 21 becomes the second reference pressure Pref2. In this process, the pressure detected by the pressure sensor 21 maintains the second reference pressure Pref2 after time t5 in FIG. In addition, after time t5, as indicated by a broken line F, the inside of the canister 10 and the inside of the fuel tank 8 are also depressurized and approach the second reference pressure Pref2. At this time, the flow path indicated by hatching in FIG. 8 (D1) is decompressed, and the interior of the canister 10 and the fuel tank 8 are decompressed. The flow rate characteristic at that time is indicated by a symbol M3 in the graph of FIG. 8 (D2).

In S8, the ECU 50 determines whether or not a predetermined time has elapsed since the detected pressure of the pressure sensor 21 has reached the second reference pressure Pref2. The ECU 50 repeats the process of S8 until a predetermined time has elapsed.

In S8, the ECU 50 may perform a process of determining whether or not the detected pressure of the pressure sensor 21 has become larger than the second reference pressure Pref2 instead of or in addition to determining the elapse of the predetermined time. Good. In that case, the ECU 50 repeats the process of S8 until the detected pressure of the pressure sensor 21 becomes larger than the second reference pressure Pref2. Further, the ECU 50 may perform processing for determining whether or not a predetermined time has elapsed since the pressure detected by the pressure sensor 21 has been switched to high speed rotation of the pump.

In the process of S8, the flow path indicated by hatching in FIG. 9 (E1) is further depressurized, and the inside of the canister 10 and the fuel tank 8 are further depressurized. Thereby, when the small hole below the sum total of the cross-sectional area of the reference | standard orifice 22 and the cross-sectional area of the ventilation | gas_flowing orifice 23 is opened in the fuel tank 8 or the canister 10, or the hole is not opened in the fuel tank 8 or the canister 10 In this case, the pressure detected by the pressure sensor 21 is lower than the second reference pressure Pref2 after time t6 in FIG. The flow rate characteristic at that time shifts from that indicated by the symbol M3 in the graph of FIG. 9E2 to that indicated by the symbol M4 along the solid line arrow Ah2.

On the other hand, when a hole larger than the sum of the cross-sectional area of the reference orifice 22 and the cross-sectional area of the vent orifice 23 is opened in the fuel tank 8 or the canister 10, a broken line X is shown in the graph of the detected pressure of the pressure sensor 21 in FIG. As shown, the detected pressure is maintained at the second reference pressure Pref2.

ECU50 will transfer a process to S9, if predetermined time passes, after the detection pressure of the pressure sensor 21 becomes 2nd reference pressure Pref2.

In S9, the ECU 50 switches the drive of the pump 20 to low speed rotation. In this process, the pump 20 is switched to low speed rotation at time t7 in FIG. 7, and thereafter the detected pressure decreases. At this time, although the pressure of the flow path indicated by hatching in FIG. 9 (F1) is small, the switching valve 30 maintains the state of the second position without switching. The flow rate characteristic at that time shifts from that indicated by the symbol M4 in the graph of FIG. 9 (F2) to that indicated by the symbol M5.

In S10, the ECU 50 determines whether or not a predetermined time has elapsed since the drive of the pump 20 was switched to low speed rotation. The ECU 50 repeats the process of S10 until a predetermined time has elapsed. In this process, the pressure detected by the pressure sensor 21 is maintained at a constant pressure after time t8 in FIG. The flow rate characteristic at that time is indicated by the symbol M5 in the graph of FIG. 9 (F2).

In S10, the ECU 50 may perform a process of determining whether or not the detected pressure of the pressure sensor 21 is maintained at the predetermined pressure instead of or at the same time as determining whether the predetermined time has elapsed. Good. In that case, ECU50 repeats the process of S10 until the detection pressure of the pressure sensor 21 maintains a predetermined pressure.

In S11, the ECU 50 stores the detected pressure of the pressure sensor 21 as the system pressure Pt. This process is performed between times t8 and t9 in FIG. In the present disclosure, the system pressure means that the switching valve 30 blocks communication between the pump 20 and the atmosphere other than the atmosphere in the atmosphere passage 24 and rotates the pump 20 at a low speed in a state where the second communication passage 28 and the tank passage 25 are communicated. Is the pressure detected by the pressure sensor 21 at the time.

In S12, the ECU 50 compares the first reference pressure Pref1 and the system pressure Pt. When the absolute value of the system pressure Pt is greater than the absolute value of the first reference pressure Pref1, and the difference between the absolute value of the system pressure Pt and the absolute value of the first reference pressure Pref1 is greater than a predetermined threshold, the ECU 50 To S13. Here, the predetermined threshold is a value set in consideration of an output error of the pressure sensor 21 and the like, and is a difference between the leak determination threshold T and the first reference pressure Pref1.

In S13, the ECU 50 determines that the fuel vapor leakage hole from the fuel tank 8 or the canister 10 is smaller than the reference value. The reference value is a value corresponding to the cross-sectional area of the reference orifice 22.

On the other hand, in S12, the ECU 50 determines that the absolute value of the system pressure Pt is equal to or smaller than the absolute value of the first reference pressure Pref1, or the difference between the absolute value of the system pressure Pt and the absolute value of the first reference pressure Pref1 is a predetermined value. When it is below the threshold, the process proceeds to S14. This is a case where the detected pressure of the pressure sensor 21 is the one indicated by the broken line Y in the lower graph of FIG. 7 (system pressure Pty shown in FIG. 7).

In S14, the ECU 50 determines that the fuel vapor leakage from the fuel tank 8 or the canister 10 is larger than the reference value.

In S15, the ECU 50 performs a process of turning on a warning lamp on the instrument panel during the next engine operation.

In S16, the ECU 50 stops driving the pump 20, or reversely rotates the impeller of the pump 20. In either case, the detected pressure decreases after time t9 in FIG.

As indicated by the solid line after time t9 in FIG. 7, when the impeller of the pump 20 is rotated in reverse, the flow path indicated by hatching in FIG. 9 (G1) is pressurized, and the pressure passage 26 and the atmospheric passage 24 The switching valve 30 starts a switching operation from the second position to the first position.

When the driving of the pump 20 is stopped, the pressure of the flow path indicated by hatching in FIG. 9 (G1) approaches 0, and the differential pressure between the pressure passage 26 and the atmospheric passage 24 becomes smaller than the return pressure of the switching valve 30. The switching valve 30 starts a switching operation from the second position to the first position.

When the switching valve 30 is switched to the first position, the ECU 50 stops driving the pump 20 in S17 and ends the process.

In addition, after the switching valve 30 is switched to the first position, the ECU 50 may drive the pump 20 in the normal direction at a low speed. When this process is performed, the detected pressure of the pressure sensor 21 decreases after time t10 in FIG. 7, and the first reference pressure Pref1 is maintained after time 11. At this time, the flow path indicated by hatching in FIG. 9 (H 1) is decompressed, and air flows through the reference orifice 22 of the first communication path 27 communicating with the pressure path 26. The flow rate characteristic at that time shifts from that indicated by the symbol M5 in the graph of FIG. 9 (H2) to that indicated by the symbol M1. At this time, the ECU 50 compares the first reference pressure Pref1 detected after time 11 with the first reference pressure Pref1 detected in S4, and determines whether or not the error of these values is within a predetermined range.

Note that the ECU 50 may measure the atmospheric pressure P0 again, and compare the detected value with the atmospheric pressure P0 detected in S1, and determine whether or not the error of these values is within a predetermined range.

The ECU 50 ends the process when one or both of these errors are within a predetermined range. On the other hand, when one or both of these errors are larger than the predetermined range, the ECU 50 discards the determination made in S13 to S15.

In the inspection method described above, the processing from S2 to S4 corresponds to the first reference pressure detection step, the processing from S5 to S8 corresponds to the tank pressure reduction step, the processing from S9 to S11 corresponds to the system pressure detection step, and S12 To S14 correspond to the determination step.

The inspection apparatus 1 or the inspection method of the first embodiment has the following operational effects. (1) The inspection apparatus 1 according to the first embodiment abolishes the electromagnetic valve provided in the conventional inspection apparatus 1 by including the switching valve 30 that operates according to the differential pressure between the pressure passage 26 and the atmospheric passage 24. Is possible. Therefore, the inspection apparatus 1 can have a simple configuration and can be downsized. Moreover, since the test | inspection apparatus 1 does not use a solenoid valve, it is possible to reduce power consumption.

Further, the inspection apparatus 1 reduces the reference pressure by the reference orifice 22, that is, the first reference pressure Pref1 and the fuel tank 8 only by reducing the pressure passage 26 by driving the pump 20 by the flow path configuration. It is possible to detect both of the system pressures Pt. Therefore, since the inspection apparatus 1 can detect both the reference pressure and the system pressure Pt with the rotation direction of the impeller of the pump 20 being the same, the detection accuracy can be improved.

(2) The switching valve 30 provided in the inspection device 1 of the first embodiment has a pressure chamber 32, an atmospheric pressure chamber 33, and a tank pressure chamber 34 formed inside the housing 31. The valve member 40 operates according to the differential pressure between the pressure chamber 32 and the atmospheric pressure chamber 33. With the configuration of the switching valve 30, the valve member 40 can be operated by changing the differential pressure between the pressure chamber 32 and the atmospheric pressure chamber 33 by controlling the rotation speed of the pump 20.

(3) In 1st Embodiment, the valve member 40 with which the switching valve 30 is provided is the absolute value of the differential pressure | voltage of the pressure chamber 32 and the atmospheric pressure chamber 33 when the valve member 40 moves to a 2nd position from a 1st position. Thus, the absolute value of the differential pressure between the pressure chamber 32 and the atmospheric pressure chamber 33 when the valve member 40 moves from the second position to the first position is smaller.

As a result, even if the absolute value of the differential pressure between the pressure chamber 32 and the atmospheric pressure chamber 33 is reduced after the pump 20 is rotated at a high speed to bring the valve member 40 into the second position, the valve member 40 is moved to the second position. It is possible to stay in place. Therefore, the system pressure Pt can be detected by rotating the pump 20 at a low speed while the valve member 40 is in the second position.

(4) In the first embodiment, the valve member 40 included in the switching valve 30 includes a diaphragm 42 and a valve body 43 that operates together with the diaphragm 42. The valve body 43 has a second pressure receiving surface exposed to the atmosphere port 36 when seated on the second valve seat 331 than the first pressure receiving surface 431 exposed to the vent port 38 when seated on the first valve seat 381. 432 is smaller.

Thus, when the valve member 40 is in the second position, the tank member 40 is in the second position rather than the force received by the valve body 43 due to the differential pressure between the tank pressure chamber 34 and the second communication passage 28 when the valve member 40 is in the first position. The force received by the valve body 43 due to the differential pressure between the pressure chamber 34 and the atmospheric pressure chamber 33 is small. Therefore, the switching valve 30 can make the absolute value of the return pressure smaller than the absolute value of the operating pressure.

(5) In the first embodiment, the absolute value of the operating pressure of the switching valve 30 is larger than the absolute value of the first reference pressure Pref1 or the absolute value of the leak judgment threshold (T), and the second reference pressure Pref2 It is set smaller than the absolute value.

Thus, after measuring the first reference pressure Pref1, the valve member 40 can be moved from the first position to the second position, and the tank can be decompressed in a short time.

In the first embodiment, the absolute value of the return pressure of the switching valve 30 is set to be smaller than the absolute value of the first reference pressure Pref1 or the absolute value of the leak judgment threshold (T) and larger than 0.

Thus, it is possible to measure the system pressure Pt by rotating the pump 20 at a low speed with the valve member 40 held at the second position.

(6) The inspection apparatus 1 according to the first embodiment includes the ventilation orifice 23 in the second communication path 28.

The vent orifice 23 is a pressure introduction port from the atmospheric passage 24 and the tank passage 25 through the second communication passage 28 and the pressure passage 26 while the valve member 40 of the switching valve 30 is moving between the first position and the second position. The flow of air from 35 to the pressure chamber 32 is suppressed. Therefore, the vent orifice 23 can guarantee the operation of the valve member 40.

(7) The evaporative fuel leakage inspection method according to the first embodiment includes a first reference pressure detection step (S2-S4), a tank pressure reduction step (S5-S8), a system pressure detection step (S9-S11), and a determination step ( S12-S14).

Thus, the evaporative fuel leakage inspection method can control the operation of the switching valve 30 by changing the rotational speed of the pump 20. Further, in this inspection method, the evaporated fuel leakage inspection can be completed in a short time by rotating the pump 20 at a high speed to decompress the fuel tank 8 and the canister 10. Therefore, this inspection method can reduce the electric power consumed for the evaporative fuel leakage inspection.

(Second Embodiment)
A method for inspecting an evaporated fuel leak according to the second embodiment of the present disclosure will be described with reference to the flowcharts of FIGS. 10 and 11.

In the inspection method of the second embodiment, the processing from S1 to S7 is the same as the processing of the first embodiment.

In the second embodiment, in S20 following S7, the ECU 50 determines whether or not the detected pressure of the pressure sensor 21 has become larger than the second reference pressure Pref2. If the ECU 50 determines in S20 that the pressure detected by the pressure sensor 21 has become larger than the second reference pressure Pref2, the process proceeds to S9.

On the other hand, if the ECU 50 determines in S20 that the detected pressure of the pressure sensor 21 is equal to or lower than the second reference pressure Pref2, the process proceeds to S21, and the detected pressure of the pressure sensor 21 becomes the second reference pressure Pref2. It is determined whether or not a predetermined time has passed. If the predetermined time has not elapsed in S21, the ECU 50 returns the process to S20.

On the other hand, in S21, when a predetermined time has elapsed since the detected pressure of the pressure sensor 21 becomes the second reference pressure Pref2, the ECU 50 proceeds to S22. The predetermined time here is set to a time during which the fuel tank 8 and the canister 10 can be sufficiently decompressed by driving the pump 20.

In S22, the ECU 50 determines that the fuel tank 8 or the canister 10 has a hole larger than the sum of the cross-sectional area of the reference orifice 22 and the cross-sectional area of the ventilation orifice 23. In the second embodiment, the sum of the cross-sectional area of the reference orifice 22 and the cross-sectional area of the ventilation orifice 23 is referred to as a large diameter reference value. On the other hand, the cross-sectional area of the reference orifice 22 is referred to as a small diameter reference value.

In S23, the ECU 50 performs a process of turning on a warning lamp on the instrument panel during the next engine operation, and ends the process.

As described above, when the ECU 50 determines in S20 that the detected pressure of the pressure sensor 21 is greater than the second reference pressure Pref2, the process proceeds to S9. The subsequent processes from S9 to S12 are the same as those in the first embodiment.

In S12, the ECU 50 determines that the absolute value of the system pressure Pt is equal to or less than the absolute value of the first reference pressure Pref1, or the difference between the absolute value of the system pressure Pt and the absolute value of the first reference pressure Pref1 is greater than a predetermined threshold value. When it is smaller, the process proceeds to S24.

In S24, the ECU 50 determines that the evaporated fuel leakage from the fuel tank 8 or the canister 10 is larger than the small diameter reference value and smaller than the large diameter reference value. In S15, the ECU 50 performs a process of turning on the warning lamp on the instrument panel during the next engine operation.

The subsequent processes in S16 and S17 are the same as those in the first embodiment.

In the inspection method described above, the processing from S20 to S22 corresponds to the large diameter determination step, and the processing from S12, S13, and S24 corresponds to the small diameter determination step.

The inspection method of the second embodiment can detect an evaporative fuel leak larger than the large diameter reference value by the large diameter determination step. Moreover, it is possible to detect the fuel vapor leakage between the small diameter reference value and the large diameter reference value by the small diameter determination step.

(Third embodiment)
FIG. 12 shows an inspection apparatus 1 according to the third embodiment of the present disclosure. In the third embodiment, the valve member 40 of the switching valve 30 includes a first valve body 401 and a second valve body 402. The first valve body 401 can be seated and separated from the first valve seat 381, and the second valve body 402 can be seated and separated from the second valve seat 331. The first valve body 401 and the second valve body 402 are provided at a predetermined distance. Thereby, in order to switch the 1st position and the 2nd position in change valve 30, it is possible to shorten time for valve member 40 to move. Therefore, in the switching valve 30, the air flowing into the tank pressure chamber 34 from the atmospheric passage 24 and the tank passage 25 is transferred from the ventilation port 38 while the valve member 40 is moving between the first position and the second position. It is possible to reduce the flow rate flowing from the pressure introduction port 35 to the pressure chamber 32 through the second communication passage 28 and the pressure passage 26. Therefore, the switching valve 30 can guarantee the operation of the valve member 40.

It should be noted that the ventilation orifice 23 of the second communication path 28 can be eliminated by shortening the time for the valve member 40 to move between the first position and the second position. It is also possible to adjust the flow passage cross-sectional area of the second communication path 28 so that the second communication path 28 has the same function as the vent orifice 23.

(Fourth embodiment)
An inspection apparatus 1 according to the fourth embodiment of the present disclosure is shown in FIG. In the fourth embodiment, the ventilation orifice 23 is provided between the second communication passage 28 of the pressure passage 26 and the suction port 201. Specifically, as shown in FIG. 13, when the pressure passage 26 communicates with the suction port 201, the second communication passage 28, and the first communication passage 27 of the pump 20 in order from the pressure introduction port 35, the ventilation orifice 23 is provided between a portion P261 connected to the second communication passage 28 of the pressure passage 26 and a portion P262 connected to the suction port 201 of the pressure passage 26. At this time, the sectional area of the ventilation orifice 23 is larger than the sectional area of the reference orifice 22.

Next, an evaporative fuel leakage inspection method according to the fourth embodiment will be described with reference to the flowchart of FIG. 14 and the time chart of FIG. The method for inspecting fuel vapor leakage according to the fourth embodiment is performed along the flowcharts shown in FIGS. 14 and 6. The upper part of FIG. 15 shows the time axis in the evaporative fuel leakage inspection, the middle part is a graph showing the rotational speed of the pump 20 with time, and the lower part shows the detected pressure of the pressure sensor 21 with time. It is a graph which shows a change. Note that the pump 20 depressurizes the pressure passage 26 during normal rotation. Here too, when referring to the magnitude of the pressure, it means the absolute value.

In the inspection method of the fourth embodiment, the processing from S1 to S6 is the same as the processing of the first embodiment. When the drive of the pump 20 is switched to high speed rotation in S5, the pressure detected by the pressure sensor 21 gradually decreases after time t4 in FIG. When the detected pressure of the pressure sensor 21 reaches the operating pressure, the valve member 40 starts moving from the first position to the second position (S6). In the fourth embodiment, when the valve member 40 starts moving, the pressure detected by the pressure sensor 21 once returns to the atmospheric pressure at time t5 in FIG. 15, and then the pressure waveforms in the canister 10 and the fuel tank 8 (broken line) It shows the same change as F). At this time, when a hole larger than the sum of the cross-sectional area of the reference orifice 22 and the cross-sectional area of the ventilation orifice 23 is opened in the fuel tank 8 or the canister 10, as shown by a broken line X in FIG. It becomes constant at the pressure according to.

In S40, the ECU 50 determines whether or not a predetermined time has elapsed since the detected pressure of the pressure sensor 21 has reached the target value. The ECU 50 repeats the process of S40 until a predetermined time has elapsed. Here, the target value in S40 is a value determined from the pressure resistance of the fuel tank 8, the size of the hole to be detected, and the like.

In S40, the ECU 50 may perform a process of determining whether or not the detected pressure of the pressure sensor 21 has become larger than the target value instead of determining whether or not the predetermined time has elapsed. In that case, the ECU 50 repeats the process of S40 until the detected pressure of the pressure sensor 21 becomes larger than the target value. Further, the ECU 50 may perform processing for determining whether or not a predetermined time has elapsed since the pressure detected by the pressure sensor 21 has been switched to high speed rotation of the pump.

ECU50 will transfer a process to S9, if predetermined time passes after the detection pressure of the pressure sensor 21 becomes a target value.

The subsequent processes from S9 to S17 are the same as those in the first embodiment.

In the inspection apparatus 1, when the valve body 43 is in the second position, the atmospheric pressure chamber 33 and the pressure chamber 32 communicate with each other via the second communication passage 28 and the pressure passage 26. At this time, a differential pressure between the pressure chamber 32 and the atmospheric pressure chamber 33 can be formed by the ventilation orifice 23. Thereby, the state in which the valve body 43 exists in a 2nd position is maintainable.

When the system pressure Pt is detected, the pressure passage 26 in the vicinity of the pressure sensor 21 and the fuel tank 8 and the canister 10 are connected to the second communication passage 28 from the portion P263 of the pressure passage 26 connected to the pressure sensor 21. Are communicated via the pressure passage 26, the second communication passage 28, the tank pressure chamber 34, and the tank passage 25 to the portion P 261 connected to. In the inspection apparatus 1 according to the fourth embodiment, air is passed through the pressure passage 26 and the second communication passage 28 from the portion P263 connected to the pressure sensor 21 of the pressure passage 26 to the portion P261 connected to the second communication passage 28. Since there is no portion such as the orifice 23 that becomes a resistance for the gas to flow, leakage in the canister 10 and the fuel tank 8 can be detected with high accuracy.

(Fifth embodiment)
FIG. 16 shows an inspection apparatus 1 according to the fifth embodiment of the present disclosure. In the fifth embodiment, a check valve 60 is provided on the pressure passage 26 between the ventilation orifice 23 and the pump 20.

Specifically, as shown in FIG. 14, the check valve 60 is provided between the portion P261 and the portion P262 of the pressure passage 26 and on the pump 20 side of the ventilation orifice 23. The check valve 60 includes a housing 61, a valve member 62, and a spring 63.

The housing 61 has two

ports

611 and 612. The port 611 communicates with the pressure passage 26 in which the ventilation orifice 23 is provided. The port 612 communicates with the pressure passage 26 on the site P262 side. The two

ports

611 and 612 communicate with the valve chamber 610 included in the housing 61.

The valve member 62 is accommodated in the valve chamber 610 so as to be reciprocally movable. The valve member 62 can abut on a valve seat 613 formed so as to protrude around the inside of the port 612.

The spring 63 is provided in the radial direction of the valve seat 613. The first end of the spring 63 is in contact with the inner wall of the housing 61. The second end of the spring 63 is in contact with the valve member 62. The spring 63 biases the valve member 62 so that the valve member 62 is separated from the valve seat 613.

The evaporative fuel leakage inspection method according to the fifth embodiment is performed in accordance with the flowcharts shown in FIGS.

In the check valve 60, when there is no relatively large pressure difference between the gas pressure on the port 611 side and the gas pressure on the port 612 side, for example, when the pump 20 is driven at a low speed in S9, Since the valve member 62 is separated from the valve seat 613, the gas flow between the port 611 and the port 612 is allowed. On the other hand, when the gas pressure on the port 611 side is larger than the gas pressure on the port 612 side by a predetermined value or more, for example, when the drive of the pump 20 is stopped in S16, the valve member 62 contacts the valve seat 613, The gas flow between the port 611 and the port 612 is blocked. That is, the check valve 60 is a normally open check valve.

In the inspection apparatus 1 according to the fifth embodiment, when the drive of the pump 20 is stopped and the pressure chamber 32 and the fuel tank 8 are returned to the atmospheric pressure in S16, the pressure chamber 32 is supplied to the fuel tank 8 and the canister 10 and the like due to the size relationship. Gas flows in from. For this reason, the time until the pressure in the pressure chamber 32 is increased and the valve body 43 returns to the first position becomes longer.

Therefore, in the inspection apparatus 1 according to the fifth embodiment, the check valve 60 prevents the back flow from the pressure chamber 32 to the fuel tank 8 and the canister 10, and shortens the time until the valve body 43 returns to the first position. . Thereby, the time required for the inspection of the evaporated fuel leakage can be shortened.

(Sixth embodiment)
An inspection apparatus 1 according to the sixth embodiment of the present disclosure is shown in FIGS. 17 and 18. In the sixth embodiment, a switching valve 70 having a configuration different from that of the switching valve 30 is provided, and a check valve 80 is provided on the pressure passage 26 between the ventilation orifice 23 and the pump 20. In the inspection apparatus 1 according to the sixth embodiment, the pump 20 pressurizes the fuel tank 8 and the canister 10 to inspect the fuel tank 8 and the canister 10 for fuel vapor leakage.

The switching valve 70 is a differential pressure valve that operates in accordance with the differential pressure between the pressure passage 26 and the atmospheric passage 24 that changes as the pump 20 is driven. The switching valve 70 includes a housing 31, a valve member 90, and a spring 91.

The valve member 90 includes a diaphragm 92, a first valve body 901, and a second valve body 902.

The diaphragm 92 divides the pressure chamber 32 and the atmospheric pressure chamber 33 and operates by receiving a differential pressure between the pressure chamber 32 and the atmospheric pressure chamber 33.

1st valve body 901 and 2nd valve body 902 have the connection part 94 connected to the diaphragm 92, and operate | move with the diaphragm 92. FIG.

The first valve body 901 is provided at the end of the connection portion 94 protruding from the ventilation port 38 on the side opposite to the side connected to the diaphragm 92. As a result, the first valve body 901 reciprocates together with the connecting portion 94 outside the housing 31. The first valve body 901 can be seated and separated from a first valve seat 382 provided around the outside of the ventilation port 38. The first valve body 901 is biased to be seated on the first valve seat 382 by a spring 91 provided on the opposite side of the first valve body 901 from the first valve seat 382 side. The first valve body 901 may be configured to be seated on the first valve seat 382 by the elastic force of the diaphragm 92 itself without providing the spring 91.

The second valve body 902 is provided on the diaphragm 92 side of the connecting portion 94 so as to be able to reciprocate in the atmospheric pressure chamber 33. The second valve body 902 can be seated on and separated from a second valve seat 332 provided between the tank pressure chamber 34 and the atmospheric pressure chamber 33 so as to protrude in the direction of the diaphragm 92. The first valve body 901 is configured to be separated from the first valve seat 382 when the second valve body 902 is seated on the second valve seat 332.

As shown in FIG. 17, when the first valve body 901 is seated on the first valve seat 382, communication with the second communication passage 28 other than the pressure passage 26 is blocked, while the air passage 24, the tank passage 25, Are communicating. A position when the first valve body 901 is seated on the first valve seat 382 is referred to as a first position.

On the other hand, as shown in FIG. 18, when the second valve body 902 is seated on the second valve seat 332, the communication to the atmosphere 20 other than the pump 20 and the atmosphere is blocked while the second communication path 28 and the tank The passage 25 communicates with the passage 25. A position when the valve body 43 is seated on the second valve seat 331 is referred to as a second position. The valve member 90 is movable between the first position and the second position.

As shown in FIG. 17, when the first valve body 901 is seated on the first valve seat 382, the surface on which the first valve body 901 is exposed to the ventilation port 38 side is referred to as a first pressure receiving surface 903. Further, as shown in FIG. 18, a surface where the second valve body 902 is exposed to the atmospheric pressure chamber 33 side when the second valve body 902 is seated on the second valve seat 332 is referred to as a second pressure receiving surface 904. .

Here, since the opening area of the second valve seat 332 is smaller than the opening area of the first valve seat 382, the second pressure receiving surface 904 is smaller than the first pressure receiving surface 903. Therefore, the force that the differential pressure between the tank pressure chamber 34 and the atmospheric pressure chamber 33 acts on the second valve body 902 when the valve member 90 is in the second position is the first when the valve member 90 is in the first position. The differential pressure between the two communication passages 28 and the tank pressure chamber 34 is smaller than the force acting on the first valve body 901. Therefore, the differential pressure between the atmospheric passage 24 and the pressure passage 26 when the valve member 90 moves from the second position to the first position is the atmospheric passage 24 when the valve body 43 moves from the first position to the second position. And a pressure difference smaller than the pressure passage 26.

The differential pressure between the atmospheric passage 24 and the pressure passage 26 when the valve member 90 moves from the first position to the second position is referred to as operating pressure. The differential pressure between the atmospheric passage 24 and the pressure passage 26 when the valve member 90 moves from the first position to the second position is referred to as return pressure. The relationship between the operating pressure and the return pressure in the switching valve 70 is the same as that of the switching valve 30.

The check valve 80 has a housing 81, a valve member 82, and a spring 83.

The housing 81 has two

ports

811 and 812. The port 811 communicates with the pressure passage 26 in which the ventilation orifice 23 is provided. The port 812 communicates with a portion P262 connected to the discharge port 202 of the pressure passage 26. The two

ports

811 and 812 communicate with a valve chamber 810 included in the housing 81.

The valve member 82 is accommodated in the valve chamber 810 and provided so as to be reciprocally movable. The valve member 82 can contact a valve seat 813 formed around the inside of the port 812.

The spring 83 is provided on the opposite side to the valve seat 813 of the valve member 82. The first end of the spring 83 is in contact with the inner wall of the housing 81. The second end of the spring 83 is in contact with the valve member 82. The spring 83 biases the valve member 82 so that the valve member 82 contacts the valve seat 813.

In the check valve 80, when the gas pressure on the port 812 side is smaller than the gas pressure on the port 811 side, the valve member 82 contacts the valve seat 823, and therefore, between the port 811 and the port 812. Regulates gas flow at On the other hand, when the gas pressure on the port 812 side is larger than the gas pressure on the port 811 side by a predetermined value or more, for example, when the pump 20 is driven at low speed rotation, the valve member 82 is separated from the valve seat 813. , Gas flow between the port 811 and the port 812 is allowed. That is, the check valve 80 is a normally closed check valve.

Next, an evaporative fuel leakage inspection method according to the sixth embodiment will be described with reference to the time chart of FIG. The method for inspecting fuel vapor leakage according to the sixth embodiment is performed in accordance with the flowcharts shown in FIGS. 14 and 6. Note that the upper part of FIG. 19 shows the time axis in the evaporative fuel leak inspection, the middle part is a graph showing the rotation speed of the pump 20 with time, and the lower part shows the detected pressure of the pressure sensor 21 with time. It is a graph which shows a change. The pump 20 pressurizes the pressure passage 26 during normal rotation. Here, when referring to the magnitude of pressure, the absolute value is assumed.

In S1, the ECU 50 detects the atmospheric pressure P0. This process is performed in a state where the pump 20 is stopped between time t0 and time t1 in FIG. At this time, the switching valve 70 is in the first position.

In S2, the ECU 50 drives the pump 20 at a low speed. When the pump 20 starts to be driven at a low speed rotation at time t1 in FIG. 19, the pressure detected by the pressure sensor 21 starts to increase thereafter. By driving the pump 20, air flows through the reference orifice 22 of the first communication passage 27 communicating with the pressure passage 26.

In S3, the ECU 50 determines whether or not a predetermined time has elapsed from the start of driving of the pump 20. In this process, the detected pressure of the pressure sensor 21 that has increased after time t1 in FIG. 19 reaches the first reference pressure Pref1 at time t2. Then, after the time t2, the first reference pressure Pref1 is maintained. In S3, the ECU 50 determines whether or not the detected pressure of the pressure sensor 21 reaches the predetermined pressure and maintains the predetermined pressure instead of determining whether or not the predetermined time has elapsed. You may perform the process which determines.

In S4, the ECU 50 stores the detected pressure of the pressure sensor 21 as the first reference pressure Pref1 (between times t2 and t3 in FIG. 19).

In S5, the ECU 50 switches the drive of the pump 20 to high speed rotation. When the drive of the pump 20 is switched to high speed rotation at time t3 in FIG. 19, the detected pressure of the pressure sensor 21 gradually increases after time t4 in FIG. When the detected pressure of the pressure sensor 21 reaches the operating pressure, the valve member 90 starts moving from the first position to the second position (S6). In the sixth embodiment, when the valve member 90 moves, the pressure detected by the pressure sensor 21 once returns to atmospheric pressure at time t5 in FIG. 19, and then the pressure waveforms in the canister 10 and the fuel tank 8 (broken line F). ) Shows the same change.

When the valve member 90 is moving from the first position to the second position in S6, the inside of the canister 10 and the fuel tank 8 are pressurized. Thereby, when the small hole below the sum total of the cross-sectional area of the reference | standard orifice 22 and the cross-sectional area of the ventilation | gas_flowing orifice 23 is opened in the fuel tank 8 or the canister 10, or the hole is not opened in the fuel tank 8 or the canister 10 In this case, the detected pressure of the pressure sensor 21 is larger than the system pressure Pt.

On the other hand, if the fuel tank 8 or the canister 10 has a hole larger than the sum of the cross-sectional area of the reference orifice 22 and the cross-sectional area of the ventilation orifice 23, the detected pressure graph of the pressure sensor 21 in FIG. As shown, the detected pressure maintains a pressure corresponding to the size of the hole where the fuel vapor may leak.

In S40, the ECU 50 determines whether or not a predetermined time has elapsed since the detected pressure of the pressure sensor 21 has reached the target value. The ECU 50 repeats the process of S40 until a predetermined time has elapsed. When a predetermined time has elapsed since the detected pressure of the pressure sensor 21 has reached the target value, the ECU 50 proceeds to S9.

Further, the ECU 50 may determine whether or not a predetermined time has elapsed since the pump was switched to high speed rotation.

In S9, the ECU 50 switches the drive of the pump 20 to low speed rotation. In this process, the pump 20 switches to low speed rotation at time t7 in FIG. 19, and thereafter the detected pressure decreases, but the switching valve 70 maintains the state of the second position without switching.

In S10, the ECU 50 determines whether or not a predetermined time has elapsed since the drive of the pump 20 was switched to low speed rotation. The ECU 50 repeats the process of S10 until a predetermined time has elapsed. In this process, the pressure detected by the pressure sensor 21 is maintained at a constant pressure after time t8 in FIG.

In S10, the ECU 50 may perform a process of determining whether or not the detected pressure of the pressure sensor 21 is maintained at the predetermined pressure instead of or at the same time as determining whether the predetermined time has elapsed. Good.

In S11, the ECU 50 stores the detected pressure of the pressure sensor 21 as the system pressure Pt. This process is performed between times t8 and t9 in FIG.

In S12, the ECU 50 compares the first reference pressure Pref1 and the system pressure Pt. When the absolute value of the system pressure Pt is greater than the absolute value of the first reference pressure Pref1 and the absolute value of the difference between the system pressure Pt and the first reference pressure Pref1 is greater than a predetermined threshold, the ECU 50 proceeds to S13. Transition.

In S13, the ECU 50 determines that the fuel vapor leakage hole from the fuel tank 8 or the canister 10 is smaller than the reference value.

On the other hand, in S12, the ECU 50 determines that the absolute value of the system pressure Pt is equal to or less than the absolute value of the first reference pressure Pref1, or the absolute value of the difference between the system pressure Pt and the first reference pressure Pref1 is equal to or less than a predetermined threshold value. When there is, the process proceeds to S14. This is a case where the detected pressure of the pressure sensor 21 is the one indicated by the broken line Y in the lower graph of FIG. 19 (system pressure Pty shown in FIG. 19).

In S16, the ECU 50 stops driving the pump 20, or reversely rotates the impeller of the pump 20. In either case, the detected pressure decreases after time t9 in FIG. When the differential pressure between the pressure passage 26 and the atmospheric passage 24 becomes smaller than the return pressure of the switching valve 70, the switching valve 70 starts a switching operation from the second position to the first position.

When the switching valve 70 is switched to the first position, the ECU 50 stops driving the pump 20 in S17. At this time, the check valve 80, which is a normally closed check valve, blocks the gas flow between the port 811 and the port 812. Thereby, after the pressure of the pressure chamber 32 having a smaller volume than the fuel tank 8 and the canister 10 becomes close to the atmospheric pressure to some extent, the pressure in the fuel tank 8 and the canister 10 returns to the atmospheric pressure.

Thus, the evaporative fuel leakage inspection method according to the sixth embodiment is completed.

In the inspection apparatus 1 according to the sixth embodiment, the fuel tank 8 and the canister 10 are pressurized and the fuel vapor leakage is inspected. At this time, when the drive of the pump 20 is stopped in S16 and the pressure chamber 32, the fuel tank 8 and the like are returned to the atmospheric pressure, the gas flows from the pressure chamber 32 into the fuel tank 8, the canister 10 and the like due to the size relationship. For this reason, the time until the pressure in the pressure chamber 32 is increased and the valve body 43 returns to the first position becomes longer. At this time, the check valve 80 prevents backflow from the pressure chamber 32 to the fuel tank 8 and the canister 10. Thereby, the time until the valve member 90 returns to the first position can be shortened.

In the inspection device 1 according to the sixth embodiment, the valve member 90 includes a first valve body 901 that can be seated on the first valve seat 382 and a second valve body 902 that can be seated on the second valve seat 332. ing. Since the first valve body 901 and the second valve body 902 are provided at a predetermined distance, the time required for the valve member 90 to move to switch between the first position and the second position in the switching valve 70 is shortened. can do.

(Other embodiments)
In the above-described embodiment, the inspection apparatus 1 operates the switching valve 30 by reducing the pressure passage 26 by driving the pump 20, and detects the first reference pressure Pref1, the second reference pressure Pref2, and the system pressure Pt. Went. On the other hand, in another embodiment, the inspection device 1 operates the switching valve 30 by pressurizing the pressure passage 26 by driving the pump 20, thereby operating the first reference pressure Pref 1, the second reference pressure Pref 2, and The system pressure Pt may be detected. In this case, the driving of the pump 20 shown in the middle stage of FIG. 7 is a graph in which the normal rotation and the reverse rotation are reversed with the rotation speed 0 as the center. Further, the change in the detected pressure of the pressure sensor 21 shown in the lower part of FIG. 7 is a graph in which the decompression side and the pressurization side are reversed with the atmospheric pressure P0 as the center.

As described above, the present disclosure is not limited to the above-described embodiment, and can be applied to various forms without departing from the gist thereof.

In the fourth to sixth embodiments, the vent orifice 23 is provided between a portion P261 connected to the second communication passage 28 of the pressure passage 26 and a portion P262 connected to the suction port 201 or the discharge port 202 of the pressure passage 26. ing. However, if the vent orifice 23 is provided between the part P264 (see FIG. 13) connected to the pressure introduction port 35 of the pressure passage 26 and the part P262, or between the part P262 and the part P261 of the pressure passage 26. Good. Moreover, you may use together with the ventilation | gas_flowing orifice 23 provided in the 2nd communicating path 28 of 1st, 2 embodiment.

In the sixth embodiment, the inspection apparatus 1 includes the check valve 80. The check valve 80 may not be provided. Further, the ventilation orifice 23 may not be provided.

Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims

An inspection device for detecting evaporative fuel leakage in a fuel tank (8),
A pressure sensor (21);
A reference orifice (22) provided in a first communication passage (27) communicating with a pressure passage (26) provided with the pressure sensor and a tank passage (25) communicating with the fuel tank;
One of the suction port (201) and the discharge port (202) communicates with the atmospheric passage (24) communicating with the atmosphere, the other communicates with the pressure passage, and the pump (20) capable of depressurizing or pressurizing the pressure passage When,
It operates according to the differential pressure between the pressure passage and the atmospheric passage that changes as the pump is driven, shuts off the communication of the second communication passage (28) leading to the pressure passage to other than the pressure passage, and the atmosphere. A switching valve capable of switching between a state in which the passage is communicated with the tank passage and a state in which the passage in the atmospheric passage is disconnected from the pump and the atmosphere and the second passage and the tank passage are communicated. 30, 70)
An inspection apparatus comprising:
The switching valve is
A housing (31) in which a pressure chamber (32), an atmospheric pressure chamber (33) and a tank pressure chamber (34) are formed;
A pressure introduction port (35) communicating the pressure passage and the pressure chamber;
An atmospheric port (36) communicating the atmospheric passage with the atmospheric pressure chamber;
A tank port (37) communicating the tank passage and the tank pressure chamber;
A vent port (38) communicating the second communication path and the tank pressure chamber;
A valve member (40, 90) that operates in accordance with a differential pressure between the pressure chamber and the atmospheric pressure chamber;
The inspection apparatus according to claim 1.
The valve member shuts off the communication of the second communication path that communicates with the pressure passage to other than the pressure passage, and communicates the atmospheric passage with the tank passage, the pump in the atmospheric passage, It is possible to move between a second position that cuts off communication to the atmosphere other than the atmosphere and communicates the second communication passage and the tank passage;
The absolute value of the differential pressure between the pressure chamber and the atmospheric pressure chamber when the valve member moves from the second position to the first position is the valve member moves from the first position to the second position. The inspection apparatus according to claim 2, wherein the absolute value of the differential pressure between the pressure chamber and the atmospheric pressure chamber is smaller.
The valve member is
A diaphragm (42, 92) that divides the pressure chamber and the atmospheric pressure chamber and operates by receiving a differential pressure between the pressure chamber and the atmospheric pressure chamber;
The first seat surface (45) is seated and separated from the first valve seat (381, 382) provided in the vent port, and the second seat surface (46) is formed between the tank pressure chamber and the atmospheric pressure chamber. A valve body (43, 901, 902) seated and separated from a second valve seat (331, 332) provided therebetween, and operating together with the diaphragm;
Have
When the valve body is seated on the second valve seat, the second pressure receiving surface (42, 904) exposed to the atmospheric pressure chamber side is exposed to the vent port side when seated on the first valve seat. The inspection apparatus according to claim 3, which is smaller than the first pressure receiving surface (41, 903).
When the pump is rotated at a low speed, the atmospheric pressure that passes through only the first communication path provided with the reference orifice is defined as a first reference pressure (Pref1), and when the pump is rotated at a high speed, the first communication path and the If the atmospheric pressure passing through the second communication path is the second reference pressure (Pref2),
The absolute value of the differential pressure between the pressure passage and the atmospheric passage when the valve member moves from the first position to the second position is based on the absolute value of the first reference pressure or the first reference pressure. Greater than the absolute value of the threshold value (T) for leak judgment set in the above and smaller than the absolute value of the second reference pressure,
The absolute value of the differential pressure between the pressure passage and the atmospheric passage when the valve member moves from the second position to the first position is the absolute value of the first reference pressure or the absolute value of the threshold value for the leak determination. The inspection apparatus according to claim 3, wherein the inspection apparatus is set to be smaller than the value and larger than 0.
The pressure passage includes, in order from the side communicating with the pressure introduction port, the suction port or the discharge port of the pump, the second communication passage that communicates the switching valve and the pressure passage, and the first communication passage. Communicated with
The vent orifice (23) provided between the site | part (P261) connected to the said 2nd communicating path of the said pressure channel from the site | part (P264) connected to the said pressure introduction port is further provided. The inspection apparatus according to any one of 1 to 5.
The pressure passage includes, in order from the side communicating with the pressure introduction port, the suction port or the discharge port of the pump, the second communication passage that communicates the switching valve and the pressure passage, and the first communication passage. Communicated with
A check valve (60, 60) provided between a portion (P261) connected to the second communication passage of the pressure passage to a portion (P262) connected to the suction port or the discharge port of the pump. 80) The inspection apparatus according to any one of claims 2 to 6, further comprising: 80).
The check valve is a normally open type, and when the pump depressurizes the pressure passage, the pressure at the port (611) of the check valve on the side connected to the second communication passage of the pressure passage is 8. The inspection device according to claim 7, wherein the inspection device is closed when the pressure passage becomes larger than a pressure at a port (612) of the check valve on the side connected to the suction port or the discharge port of the pump in the pressure passage.
The check valve is a normally closed type, and when the pump pressurizes the pressure passage, the check valve port on the side of the pressure passage connected to the suction port or the discharge port of the pump ( The inspection apparatus according to claim 7, wherein the valve is opened when the pressure in 812) is greater than a predetermined value compared to the pressure in the port (811) of the check valve on the side connected to the second communication path of the pressure path.
The inspection apparatus according to any one of claims 2 to 9, further comprising a ventilation orifice (23) provided in the second communication path that connects the switching valve and the pressure path.
A pressure sensor (21);
A reference orifice (22) provided in a first communication passage (27) communicating with a pressure passage (26) provided with the pressure sensor and a tank passage (25) communicating with the fuel tank (8);
One of the suction port (201) and the discharge port (202) communicates with the atmospheric passage (24) communicating with the atmosphere, the other communicates with the pressure passage, and the pump (20) capable of depressurizing or pressurizing the pressure passage When,
It operates according to the differential pressure between the pressure passage and the atmospheric passage that changes as the pump is driven, shuts off the communication of the second communication passage (28) leading to the pressure passage to other than the pressure passage, and the atmosphere. A switching valve capable of switching between a state in which the passage is communicated with the tank passage and a state in which the passage in the atmospheric passage is disconnected from the pump and the atmosphere and the second passage and the tank passage are communicated. 30, 70)
In the method for inspecting evaporative fuel leakage using an inspection apparatus comprising:
The pressure sensor is configured to rotate the pump at a low speed with the switching valve blocking communication of the second communication path communicating with the pressure path to other than the pressure path and in communication with the atmosphere path and the tank path. A first reference pressure detecting step (S2-S4) for storing the detected pressure as a first reference pressure;
The pump is switched from a low speed rotation to a high speed rotation to operate the switching valve, and the switching valve blocks the communication of the atmospheric passage to other than the pump and the atmosphere and communicates the second communication passage and the tank passage. A tank depressurization step (S5-S8) for depressurizing the tank passage in the
A system pressure detecting step (S9-S11) for storing the pressure detected by the pressure sensor as a system pressure by rotating the pump at a low speed in the same switching valve state as the tank depressurizing step;
The first reference pressure and the system pressure are compared, and the absolute value of the system pressure is smaller than the absolute value of the first reference pressure, or the absolute value of the difference between the system pressure and the first reference pressure Is smaller than a predetermined threshold, it is determined that the fuel vapor leakage of the fuel tank is larger than a reference value,
When the absolute value of the system pressure is greater than the absolute value of the first reference pressure and the absolute value of the difference between the system pressure and the first reference pressure is greater than a predetermined threshold value, the fuel tank leaks evaporative fuel A determination step (S12-S14) for determining that is smaller than the reference value;
Including inspection methods.
The determination step is a small diameter determination step, the reference value is a small diameter reference value, the reference value larger than the small diameter reference value is a large diameter reference value,
When the atmospheric pressure passing through the first communication path and the second communication path when the pump is rotated at a high speed is the second reference pressure,
In the tank depressurization step, when the absolute value of the pressure detected by the pressure sensor is equal to or smaller than the absolute value of the second reference pressure for a predetermined time, the fuel tank evaporative fuel leaks The inspection method according to claim 11, further comprising a large diameter determination step (S20-S22) for determining that the value is larger than the reference value.