WO2021039152A1

WO2021039152A1 - Vaporized fuel treatment device

Info

Publication number: WO2021039152A1
Application number: PCT/JP2020/027100
Authority: WO
Inventors: 義彦本田; 善和宮部; 昌慶品川; 尚人武関
Original assignee: 愛三工業株式会社
Priority date: 2019-08-30
Filing date: 2020-07-10
Publication date: 2021-03-04
Also published as: JP2021038674A

Abstract

In this vaporized fuel treatment device, a fuel passage or a return passage is provided with a heat reception part for heat from an internal combustion engine, and a control unit causes a fuel pump to be operated after warming of the internal combustion engine is completed, thereby returning the fuel heated by the heat reception part to a fuel tank via the return passage, and the control unit performs leak detection on the basis of a change in a pressure value detected by a pressure sensor after heating the fuel inside the fuel tank and generating a pressure difference inside the fuel tank.

Description

Evaporative fuel processing equipment

The present disclosure relates to an evaporative fuel processing device that processes evaporative fuel generated in a fuel tank of an internal combustion engine mounted on a vehicle.

An evaporative fuel treatment device is used to prevent the evaporative fuel generated in the fuel tank from being released to the atmosphere. In this evaporated fuel processing apparatus, the evaporated fuel in the fuel tank is introduced into the canister containing the adsorbent and temporarily adsorbed on the adsorbent. The evaporated fuel adsorbed on the adsorbent is purged when the purge execution condition determined based on the operating conditions of the internal combustion engine is satisfied, and is purged to the intake passage of the internal combustion engine via the purge passage.

Some of such evaporative fuel treatment devices have a function of performing a leak inspection to determine whether or not there is a leak in the portion including the fuel tank and the canister. As an apparatus of this type, for example, there is one described in Patent Document 1. In the apparatus of Patent Document 1, an air supply pump is provided, the fuel tank and the canister are pressurized by the air supply pump, and leak detection is performed based on the subsequent pressure change. Further, as another device, for example, there is one described in Patent Document 2. In the device of Patent Document 2, the fuel tank is sealed by an on-off valve, and leak detection is performed based on the pressure change after the pressure in the fuel tank is increased by the change in the outside air temperature.

Japanese Unexamined Patent Publication No. 5-272417 U.S. Pat. No. 7,448367

However, in the device described in Patent Document 1, a dedicated air supply pump is required for leak detection, which causes an increase in cost. On the other hand, the apparatus described in Patent Document 2 does not cause an increase in cost, but since the pressure change depends on the change in the outside air temperature, the pressure change may not occur depending on the outside air temperature, and the opportunity for leak detection is limited. There is a risk of being lost.

Therefore, the present disclosure has been made to solve the above-mentioned problems, and an evaporative fuel treatment apparatus capable of detecting a leak without installing a new pump and securing an opportunity for detecting a leak. The purpose is to provide.

A form of this disclosure made to solve the above problems is
A fuel tank for storing fuel, a fuel pump for pumping fuel in the fuel tank to the internal combustion engine via a fuel passage, a canister for storing evaporated fuel sent from the fuel tank via a vapor passage, and the fuel. A return passage that returns a part or all of the fuel pumped by the pump to the fuel tank, at least two control valves that seal the fuel tank, a pressure sensor that detects the pressure in the fuel tank, and the fuel pump. And a control unit for controlling the control valve, in an evaporative fuel processing apparatus.
The fuel passage or the return passage includes a heat receiving portion from an internal combustion engine.
After the warm-up of the internal combustion engine is completed, the control unit drives the fuel pump to return the fuel heated by the heat receiving unit to the fuel tank via the return passage, and the fuel in the fuel tank is returned. After heating to generate a differential pressure in the fuel tank, a leak inspection is performed based on the change in the pressure value detected by the pressure sensor.

In this evaporative fuel processing device, the fuel heated in the heat receiving section is returned to the fuel tank via the return passage, and the fuel in the fuel tank is heated to generate a differential pressure (positive pressure or negative pressure) in the fuel tank. Let me. Then, after generating a differential pressure in the fuel tank, a leak inspection is performed based on the change in the pressure value detected by the pressure sensor. Therefore, a pump for generating a differential pressure in the fuel tank becomes unnecessary. In addition, a differential pressure can be reliably generated in the fuel tank without being affected by the outside air temperature. Then, since the heat received from the internal combustion engine is used, the leak inspection can be reliably performed once the internal combustion engine is started and the warm-up is completed. As a result, according to this evaporative fuel treatment device, leak detection can be performed without providing a new pump, and an opportunity for leak detection can be secured.

Further, in the above-mentioned evaporated fuel processing apparatus,
After operating the control valve to seal the fuel tank, the control unit returns the fuel heated by the heat receiving unit to the fuel tank via the return passage to heat the fuel in the fuel tank. , It is preferable to generate a positive pressure in the fuel tank to perform a leak inspection.

In this way, after operating the control valve to seal the fuel tank, the fuel heated in the heat receiving section is returned to the fuel tank via the return passage to heat the fuel in the fuel tank, thereby entering the fuel tank. A differential pressure can be generated on the positive pressure side. As a result, a leak inspection by positive pressure can be performed.

Further, in the above-mentioned evaporated fuel processing apparatus,
The control unit returns the fuel heated by the heat receiving unit to the fuel tank via the return passage to heat the fuel in the fuel tank, and then operates the control valve to seal the fuel tank. Therefore, it is preferable to generate a negative pressure in the fuel tank to perform a leak inspection.

In this way, the fuel heated in the heat receiving section is returned to the fuel tank via the return passage to heat the fuel in the fuel tank, and then the control valve is operated to seal the fuel tank, thereby entering the fuel tank. A differential pressure can be generated on the negative pressure side. As a result, a leak inspection due to negative pressure can be performed. Therefore, it is possible to prevent the evaporated fuel adsorbed on the canister from being released during the leak inspection.

Further, in the above-mentioned evaporated fuel processing apparatus,
It is preferable that the control unit changes the amount of return fuel returned to the fuel tank based on the amount of fuel in the fuel tank. For example, the return fuel may be reduced as the amount of fuel in the fuel tank decreases.

If the amount of return fuel is set to a certain amount, the fuel in the fuel tank may be heated more than necessary when the amount of fuel in the fuel tank (remaining amount of fuel) is small. Therefore, by doing so, it is possible to prevent the fuel in the fuel tank from being heated more than necessary. Moreover, since the driving time of the fuel pump can be reduced, the amount of electric charge can be reduced.

Alternatively, in the above-mentioned evaporated fuel processing apparatus,
When the pressure detected by the pressure sensor becomes equal to or higher than a predetermined pressure, the control unit may stop the fuel pump and finish heating the fuel in the fuel tank.

By doing so, if the pressure in the fuel tank exceeds the predetermined pressure required for leak inspection, heating of the fuel in the fuel tank becomes unnecessary. However, if the amount of return fuel is set to a certain amount, heating of the fuel in the fuel tank may continue even if the pressure in the fuel tank exceeds the predetermined pressure. Therefore, by doing so, it is possible to prevent the fuel in the fuel tank from being heated more than necessary. Moreover, since the driving time of the fuel pump can be reduced, the amount of electric charge can be reduced.

Further, in the above-mentioned evaporated fuel processing apparatus,
The control unit returns the fuel heated by the heat receiving unit to the fuel tank via the return passage while the purge in which the evaporated fuel stored in the canister is supplied to the internal combustion engine is being executed. When the fuel in the fuel tank is heated and the internal combustion engine is stopped, it is preferable to stop the fuel pump and finish heating the fuel in the fuel tank.

In this way, the pressure in the fuel tank can be reduced by returning the return fuel to the fuel tank and heating the fuel in the fuel tank while the purge is being executed. Then, when the internal combustion engine is stopped, the heating of the fuel in the fuel tank is completed and the fuel tank is sealed. As a result, the temperature of the heated fuel drops toward the outside air temperature, so that the inside of the fuel tank can have a negative pressure, and a leak inspection due to the negative pressure can be performed.

Further, in the above-mentioned evaporated fuel processing apparatus,
A temperature sensor for detecting the temperature inside the fuel tank is provided.
When the temperature detected by the temperature sensor is equal to or higher than a predetermined temperature, the control unit preferably stops the fuel pump and finishes heating the fuel in the fuel tank.

By doing so, it is not necessary to return the return fuel to the fuel tank more than necessary during the execution of purging, so that it is possible to prevent the fuel in the fuel tank from being heated more than necessary. Further, since the rotation speed and the driving time of the fuel pump can be reduced, the electric charge consumption can be reduced and the fuel efficiency can be improved.

Further, in the above-mentioned evaporated fuel processing apparatus,
A bypass passage that returns fuel to the fuel tank without passing through the heat receiving section,
It is equipped with an on-off valve that opens and closes the bypass passage.
It is preferable that the control unit controls the on-off valve to open the bypass passage when it is not necessary to heat the fuel in the fuel tank.

By doing so, it is possible to prevent the fuel that has passed through the heat receiving portion from being returned to the fuel tank when it is not necessary to heat the fuel in the fuel tank. Therefore, it is possible to prevent the fuel in the fuel tank from being heated more than necessary.

Further, in the above-mentioned evaporated fuel processing apparatus,
It is preferable that the return passage is provided with a pressure regulator that regulates the pressure of the fuel in the passage so that the pressure does not rise above a certain level.

By doing so, since the pressure in the return passage does not increase, it is not necessary to increase the pressure resistance of the return passage, so that the cost of the device can be reduced.

Further, in the above-mentioned evaporated fuel processing apparatus,
In the case of a closed tank system including a closed valve for sealing the fuel tank, the closed valve may be used for one of the control valves.

In this way, by using the blockade valve provided in the closed tank system as one of the control valves, it is possible to perform highly accurate leak inspection while reducing the cost of the device.

According to the present disclosure, it is possible to provide an evaporative fuel treatment apparatus capable of performing leak detection without providing a new pump and securing an opportunity for leak detection.

It is the schematic which shows the whole structure of the engine system including the evaporative fuel processing apparatus of 1st Embodiment. It is a figure which shows the control flowchart of the negative pressure OBD control. It is an example of a time chart when negative pressure OBD control is performed, and shows a change in pressure in the fuel tank. It is an example of a time chart when negative pressure OBD control is performed, and shows a change in outside air temperature. It is a figure which shows the control flowchart of the positive pressure OBD control. It is an example of a time chart when positive pressure OBD control is performed, and shows a change in pressure in the fuel tank. It is an example of a time chart when positive pressure OBD control is performed, and shows a change in outside air temperature. It is a figure which shows the control flowchart of the modification of the positive pressure OBD control. It is the schematic which shows the whole structure of the engine system including the evaporative fuel processing apparatus of 2nd Embodiment. It is a figure which shows the control flowchart of the negative pressure OBD control. It is an example of a time chart when negative pressure OBD control is performed, and shows a change in pressure in the fuel tank. It is an example of a time chart when negative pressure OBD control is performed, and shows a change in the temperature inside the tank. It is an example of a time chart when negative pressure OBD control is performed, and shows a change in outside air temperature. It is a figure which shows the control flowchart of the positive pressure OBD control. It is an example of a time chart when positive pressure OBD control is performed, and shows a change in pressure in the fuel tank. It is an example of a time chart when positive pressure OBD control is performed, and shows a change in the temperature inside the tank. It is an example of a time chart when positive pressure OBD control is performed, and shows a change in outside air temperature. It is the schematic which shows the whole structure of the engine system including the evaporative fuel processing apparatus of 3rd Embodiment. It is a figure which shows the control flowchart of the negative pressure OBD control. It is a figure which shows the control flowchart of the positive pressure OBD control. It is a figure which shows the control flowchart of the modification of the positive pressure OBD control. It is the schematic which shows the whole structure of the engine system including the evaporative fuel processing apparatus of 4th Embodiment. It is a figure which shows the control flowchart of the negative pressure OBD control. It is a figure which shows the control flowchart of the positive pressure OBD control. It is the schematic which shows the whole structure of the engine system including the evaporative fuel processing apparatus of 4th Embodiment. It is the schematic which shows the modification of the evaporative fuel processing apparatus. It is the schematic which shows another modification of the evaporative fuel processing apparatus.

[First Embodiment]
The evaporated fuel treatment apparatus according to the embodiment of the present disclosure will be described in detail with reference to the drawings. In the first embodiment, the case where the evaporative fuel treatment device is applied to the engine system of the vehicle will be described.

<Overall system configuration>
The engine system to which the evaporated fuel treatment device 1 of the present embodiment is applied is mounted on a vehicle such as an automobile, and as shown in FIG. 1, the engine ENG includes air (intake air, intake air) in the engine ENG. ) Is connected to the intake passage IP. The intake passage IP is provided with a throttle valve THR that opens and closes the intake passage IP to control the amount of air flowing into the engine ENG (intake air amount). An air cleaner AC for removing foreign matter from the air flowing into the intake passage IP is provided on the upstream side (upstream side in the flow direction of the intake air) of the throttle valve THR in the intake passage IP. As a result, in the intake passage IP, air passes through the air cleaner AC and is sucked toward the engine ENG.

In such an engine system, the evaporated fuel processing device 1 of the present embodiment supplies the evaporated fuel generated in the fuel tank FT to the engine ENG via the intake passage IP and processes it. The evaporated fuel processing device 1 includes a fuel tank FT, a fuel pump FP, a return passage 13, a canister 21, a purge control valve 23, an atmosphere release valve 27, a pressure sensor 31, a control unit 40, and the like.

The fuel tank FT is configured to store the fuel supplied to the engine ENG. A fuel pump FP is provided inside the fuel tank FT, and the fuel in the fuel tank FT is supplied to the injector 11 by the fuel pump FP via the fuel passage 12. Then, fuel is supplied from the injector 11 to the engine ENG (intake port). Here, a high-pressure pump 14 is provided in the fuel passage 12. High-pressure fuel is supplied to the injector 11 by the high-pressure pump 14. The high-pressure pump 14 is an example of the “heat receiving unit from the internal combustion engine” of the present disclosure, and the fuel supplied to the high-pressure pump 14 is heated.

Further, the fuel tank FT is provided with a liquid level sensor 30 that detects the fuel liquid level in order to measure the amount of fuel (remaining amount of fuel) stored inside. Further, the fuel tank FT is provided with a pressure sensor 31 that detects the pressure in the upper space of the fuel liquid level (tank internal pressure).

Then, among the fuel supplied from the fuel tank FT through the fuel passage 12 by the fuel pump FP, the fuel that was heated by the high-pressure pump 14 and was not supplied to the injector 11 is returned to the fuel tank FT in the return passage 13. Is provided. That is, the fuel in the fuel tank FT is heated by the return fuel returned to the fuel tank FT via the return passage 13. The return passage 13 is provided with a pressure regulator 15 that regulates the pressure of the fuel in the passage so that the pressure does not rise above a certain level. Since the pressure in the return passage 13 does not increase due to the pressure regulator 15, it is not necessary to increase the pressure resistance of the return passage 13, so that the cost of the device can be reduced.

The canister 21 contains an adsorbent such as activated carbon inside, and recovers (adsorbs and holds) the evaporated fuel generated in the fuel tank FT. The canister 21 is connected to the fuel tank FT via the vapor passage 24, and temporarily adsorbs the evaporated fuel flowing from the fuel tank FT through the vapor passage 24. Further, the canister 21 communicates with the purge passage 22 and the atmospheric passage 25.

The purge passage 22 is connected to the intake passage IP and the canister 21. As a result, the purge gas (gas containing evaporated fuel) flowing out of the canister 21 flows through the purge passage 22 and is introduced into the intake passage IP. In the example shown in FIG. 1, the purge passage 22 is connected to a position on the downstream side (downstream side in the flow direction of the intake air) of the throttle valve THR.

The purge control valve 23 is provided in the purge passage 22. The purge control valve 23 opens and closes the purge passage 22. When the purge control valve 23 is closed (when the valve is closed), the purge gas in the purge passage 22 is stopped by the purge control valve 23 and does not flow to the intake passage IP. On the other hand, when the purge control valve 23 is opened (when the valve is open), the purge gas flows into the intake passage IP. The purge control valve 23 is an example of the "control valve" of the present disclosure.

One end of the atmospheric passage 25 is opened as an atmospheric opening 26, and the other end is connected to the canister 21 to communicate the canister 21 with the atmosphere. Then, the air taken in from the atmospheric opening 26 flows through the atmospheric passage 25. Further, the atmospheric passage 25 is provided with an atmospheric release valve 27 that opens and closes the atmospheric passage 25. The atmosphere release valve 27 is an example of the "control valve" of the present disclosure.

The vapor passage 24 is connected to the fuel tank FT and the canister 21. As a result, the evaporated fuel of the fuel tank FT flows into the canister 21 through the vapor passage 24.

The control unit 40 is a part of an ECU (not shown) mounted on a vehicle equipped with the above engine system, and is integrally arranged with other parts of the ECU (for example, a part that controls engine ENG). The control unit 40 may be arranged separately from other parts of the ECU. The control unit 40 includes a CPU and memories such as ROM and RAM. The control unit 40 controls the evaporative fuel processing device 1 and the engine system according to a program stored in the memory in advance. For example, the control unit 40 controls the fuel pump FP, the purge control valve 23, the atmosphere release valve 27, and the like. Further, the control unit 40 acquires output signals from the liquid level sensor 30, the pressure sensor 31, and the like.

In the evaporative fuel processing device 1 having such a configuration, when the purge condition is satisfied during the operation of the engine ENG, the control unit 40 opens the purge control valve 23 and executes the purge control. The purge control is a control for introducing the purge gas from the canister 21 to the intake passage IP via the purge passage 22.

Then, while the purge control is being executed, the engine ENG receives the air taken into the intake passage IP, the fuel supplied from the fuel tank FT and injected through the injector 11, and the intake passage IP by the purge control. The purge gas to be supplied is supplied. Then, the control unit 40 adjusts the injection time of the injector 11 and the valve opening time of the purge control valve 23 to adjust the air-fuel ratio (A / F) of the engine ENG to the optimum air-fuel ratio (for example, the ideal air-fuel ratio). adjust.

<Control contents of negative pressure OBD>
Subsequently, a failure diagnosis (On Board Diagnosis: OBD) relating to the evaporative fuel processing apparatus 1, that is, a control when performing a leak inspection will be described. In the evaporative fuel treatment device 1, it is possible to carry out either one of the negative pressure OBD in which the inside of the fuel tank FT is negative pressure and the leak inspection is performed and the positive pressure OBD in which the inside of the fuel tank FT is positive pressure and the leak inspection is performed. Is.

Therefore, first, the control when performing negative pressure OBD will be described with reference to FIG. In the present embodiment, the fuel heated by the high-pressure pump 14 is returned to the fuel tank FT via the return passage 13 to heat the fuel in the fuel tank FT, and then the purge control valve 23 and the atmosphere release valve 27 are operated. The fuel tank FT is sealed, a negative pressure is generated in the fuel tank FT, and a leak inspection is performed.

Specifically, the control unit 40 performs negative pressure OBD control based on the control chart shown in FIG. That is, after the ignition switch (IG) is turned on (step S1), the engine ENG is driven (ON) (step S2), and the purge condition is satisfied (step S3: YES), the fuel in the fuel tank FT is heated. Is started (step S4). That is, as shown by the broken line in FIG. 1, the control unit 40 controls the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13. When the fuel is constantly returned to the fuel tank FT while the engine is operating and the amount of fuel is controlled, the process of increasing the amount of return fuel is performed in S4. As a result, the heated return fuel is introduced (or increased) into the fuel tank FT, so that the fuel in the fuel tank FT is heated. The introduction of the return fuel into the fuel tank FT is continuously performed during the purge execution with the engine ENG being driven. As a result, the fuel in the fuel tank FT is heated.

After that, when the engine ENG is stopped (OFF) (step S5: YES), the control unit 40 stops the fuel pump FP, stops the introduction of the return fuel into the fuel tank FT, and enters the fuel tank FT. The heating of the fuel of (step S6) is completed. Then, when the IG is turned off (step S7: YES), the control unit 40 determines whether or not the OBD condition is satisfied (step S8). The OBD condition is a condition for OBD to be implemented and is defined based on laws and regulations. As the OBD condition, for example, the purge history and the outside air temperature are determined. Further, in the process of S7, if the IG remains ON (S7: NO), the process returns to the process of S2, and the processes of S2 to S7 are repeated.

When the OBD condition is satisfied (S8: YES), the control unit 40 closes the atmosphere release valve 27 and the purge control valve 23 (step S9). As a result, the fuel tank FT and the canister 21 are sealed. Then, since the fuel in the fuel tank FT is sealed in a heated state, the temperature in the fuel tank FT decreases toward the outside air temperature, and the inside of the fuel tank FT becomes a negative pressure.

Then, the control unit 40 determines that the pressure change (negative differential pressure) of the pressure in the fuel tank FT (tank internal pressure) from the time when the fuel tank FT and the canister 21 are sealed is equal to or more than a certain value, that is, in the fuel tank FT. Whether or not a negative pressure (for example, -3 kPa) is generated is determined based on the detected value of the pressure sensor 31 (step S10). At this time, if the pressure change is equal to or higher than a certain level (S10: YES), the control unit 40 executes a leak inspection (step S11). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and determines whether or not there is a leak in the evaporated fuel treatment device 1. The presence or absence of this leak is determined by a known method. Since the leak inspection is performed by the negative pressure in this way, it is possible to prevent the evaporated fuel adsorbed on the canister 21 from being released during the leak inspection. The determination value is corrected by the outside air temperature.

By performing control based on the control chart shown in FIG. 2, an example of the control time chart as shown in FIGS. 3A and 3B is implemented. As shown in FIGS. 3A and 3B, when the engine ENG is started at time T0 and the purge condition is satisfied at time T1, the purge is executed and the fuel in the fuel tank FT is heated by the return fuel. Is carried out. At this time, there is almost no change in the tank internal pressure. Then, when the engine ENG is stopped at time T2, the pressure inside the tank decreases, and at time T3, the pressure change in the fuel tank FT becomes equal to or higher than a certain level. After that, a leak check is executed at regular intervals from time T4 to T8. At this time, if the tank internal pressure is within the range of the determination value shown by the broken line in FIG. 3A, it is determined that there is no leak, and if it is outside the range of the determination value, it is determined that there is a leak.

<Control content of positive pressure OBD>
Next, the control when the positive pressure OBD is performed in the evaporated fuel processing apparatus 1 will be described with reference to FIG. In this case, after operating the purge control valve 23 and the air release valve 27 to seal the fuel tank FT, the fuel heated by the high-pressure pump 14 is returned to the fuel tank FT via the return passage 13 to return the fuel tank FT. The fuel inside is heated to generate a positive pressure in the fuel tank FT to perform a leak inspection.

Specifically, the control unit 40 performs positive pressure OBD control based on the control chart shown in FIG. That is, when the IG is turned on (step S20), the engine ENG is driven (ON) (step S21), and the engine ENG is stopped (OFF) after the warm-up of the engine ENG is completed (step S22), control is performed. Part 40 determines whether or not the OBD condition is satisfied (step S23).

At this time, if the OBD condition is satisfied (S23: YES), the control unit 40 closes the atmosphere release valve 27 and the purge control valve 23 (step S24). As a result, the fuel tank FT and the canister 21 are sealed. Then, heating of the fuel in the fuel tank FT is started (step S25). That is, as shown by the broken line in FIG. 1, the control unit 40 controls the drive of the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13. As a result, the heated return fuel is introduced into the fuel tank FT, so that the fuel in the fuel tank FT is heated. If the OBD condition is not satisfied (S23: NO), this processing routine is terminated.

Then, when the return fuel is introduced (returned) into the fuel tank FT by a predetermined amount (step S26: YES), the control unit 40 stops the fuel pump FP and the fuel tank of the return fuel. The introduction into the FT is stopped, and the heating of the fuel in the fuel tank FT is finished (step S27). In addition, the predetermined amount of return fuel to be introduced into the fuel tank FT is the amount of return fuel that can heat the fuel in the fuel tank (when the tank is full) so that the tank internal pressure at which the leak inspection can be performed is equal to or higher. You just have to ask.

When the heating of the fuel in the fuel tank FT is completed, the control unit 40 increases the pressure change (positive differential pressure) of the tank internal pressure from the time when the fuel tank FT and the canister 21 are sealed to a certain level or more, that is, in the fuel tank FT. Whether or not a predetermined positive pressure (for example, 3 kPa) is generated is determined based on the detected value of the pressure sensor 31 (step S28). At this time, if the pressure change is equal to or higher than a certain level (S28: YES), the control unit 40 executes a leak inspection (step S29). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and determines whether or not there is a leak in the evaporated fuel treatment device 1. The presence or absence of this leak is determined by a known method. If the pressure change is not equal to or higher than a certain level (S28: NO), this processing routine is terminated without performing a leak inspection.

By performing control based on the control chart shown in FIG. 4, an example of the control time chart as shown in FIGS. 5A and 5B is implemented. As shown in FIGS. 5A and 5B, the engine ENG is started at time T0, and when the purge condition is satisfied at time T1, the purge is executed. At this time, there is almost no change in the tank internal pressure. Then, when the engine ENG is stopped at time T2, the fuel in the fuel tank FT is heated by the return fuel. Then, the pressure inside the tank increases, and at time T3, the pressure change inside the fuel tank FT becomes equal to or higher than a certain level. After that, a leak check is executed at regular intervals from time T4 to T6. At this time, if the tank internal pressure is within the range of the determination value shown by the broken line in FIG. 5A, it is determined that there is no leak, and if it is outside the range of the determination value, it is determined that there is a leak.

<Control content of modified example of positive pressure OBD>
Here, if the internal pressure of the tank becomes equal to or higher than the predetermined pressure required for the leak inspection, the heating of the fuel in the fuel tank FT becomes unnecessary. However, in the above positive pressure OBD control, since the return fuel amount is set to a constant amount, heating of the fuel in the fuel tank FT may continue even if the tank internal pressure becomes equal to or higher than the predetermined pressure. Therefore, in the modified example, after the heating of the fuel in the fuel tank FT by the return fuel is started, when a predetermined positive pressure (for example, 3 kPa) is generated in the fuel tank FT, the fuel in the fuel tank FT is heated. To finish. Therefore, a modified example of the positive pressure OBD will be described with reference to FIG.

In this modification, the control unit 40 performs positive pressure OBD control based on the control chart shown in FIG. That is, when the IG is turned on (step S30), the engine ENG is driven (ON) (step S31), and the engine ENG is stopped (OFF) after the warm-up of the engine ENG is completed (step S32), control is performed. The unit 40 determines whether or not the OBD condition is satisfied (step S33).

At this time, if the OBD condition is satisfied (S33: YES), the control unit 40 closes the atmosphere release valve 27 and the purge control valve 23 (step S34). As a result, the fuel tank FT and the canister 21 are sealed. Then, heating of the fuel in the fuel tank FT is started (step S35). That is, as shown by the broken line in FIG. 1, the control unit 40 controls the drive of the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13. As a result, the heated return fuel is introduced into the fuel tank FT, so that the fuel in the fuel tank FT is heated. If the OBD condition is not satisfied (S33: NO), this processing routine is terminated.

After that, in the control unit 40, the pressure change (positive differential pressure) of the tank internal pressure from the time when the fuel tank FT and the canister 21 are sealed is equal to or more than a certain value, that is, a predetermined positive pressure (for example, 3 kPa) is generated in the fuel tank FT. When it occurs (step S36: YES), the fuel pump FP is stopped, the introduction of the return fuel into the fuel tank FT is stopped, and the heating of the fuel in the fuel tank FT is completed (step S37).

Then, the control unit 40 executes a leak inspection (step S38). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and determines whether or not there is a leak in the evaporated fuel treatment device 1. The presence or absence of this leak is determined by a known method.

As described above, in the modified example, when the tank internal pressure exceeds the predetermined pressure required for the leak inspection, the heating of the fuel in the fuel tank FT is stopped. Therefore, it is possible to prevent the fuel in the fuel tank FT from being heated more than necessary. Further, since the driving time of the fuel pump FP can be reduced, the electric charge consumption can be reduced.

As described above, in the evaporative fuel processing apparatus 1 of the present embodiment, the fuel heated by the high-pressure pump 14 is returned to the fuel tank FT via the return passage 13, the fuel in the fuel tank FT is heated, and then the fuel is released to the atmosphere. The valve 27 and the purge control valve 23 are closed to seal the fuel tank FT and the canister 21. As a result, a negative pressure can be generated in the fuel tank FT, so that a leak inspection due to the negative pressure can be performed based on the change in the pressure value detected by the pressure sensor 31.

Alternatively, in the evaporative fuel processing device 1 of the present embodiment, after closing the air release valve 27 and the purge control valve 23 to seal the fuel tank FT and the canister 21, the fuel heated by the high pressure pump 14 is returned to the return passage 13. The fuel is returned to the fuel tank FT via the fuel tank FT to heat the fuel in the fuel tank FT. As a result, a positive pressure can be generated in the fuel tank FT, so that a leak inspection by the positive pressure can be performed based on the change in the pressure value detected by the pressure sensor 31.

As described above, according to the evaporative fuel processing device 1 of the present embodiment, a pump for generating a differential pressure in the fuel tank FT becomes unnecessary. In addition, a differential pressure (negative pressure or positive pressure) can be reliably generated in the fuel tank without being affected by the outside air temperature. Then, since the fuel in the fuel tank FT is heated by using the heat received from the engine ENG, when the engine ENG is started and the warm-up is completed, the leak inspection can be surely performed. Therefore, according to the evaporated fuel treatment device 1 of the present embodiment, leak detection can be performed without providing a new pump, and an opportunity for leak detection can be secured.

[Second Embodiment]
Next, the evaporated fuel treatment apparatus of the second embodiment will be described with reference to FIG. 7. The second embodiment has the same basic configuration as the first embodiment, but as shown in FIG. 7, a temperature sensor 32 for detecting the temperature inside the fuel tank FT (the temperature inside the tank) is provided. The point is different. That is, in the evaporated fuel processing apparatus 1A of the second embodiment, the temperature sensor 32 is arranged in the fuel tank FT. The evaporated fuel processing device 1A of the present embodiment can also perform negative pressure OBD control or positive pressure OBD control as in the first embodiment.

<Control contents of negative pressure OBD>
Therefore, first, the control when the negative pressure OBD is performed will be described with reference to FIG. First, when the purge condition is satisfied (step S43: YES) after the IG is turned on (step S41) and the engine ENG is driven (ON) (step S42), the control unit 40 determines the temperature inside the fuel tank FT (step S43: YES). It is determined whether or not the temperature in the tank) is equal to or lower than the predetermined temperature (step S44). As the predetermined temperature, when the temperature inside the sealed tank drops to the outside air temperature during parking, the temperature at which the negative pressure required for the negative pressure OBD (for example, -3 kPa) can be generated in the fuel tank FT may be set. .. This predetermined temperature may be determined in advance by an experiment.

At this time, if the temperature inside the tank is equal to or lower than the predetermined temperature (S44: YES), the control unit 40 starts heating the fuel in the fuel tank FT (step S45). That is, as shown by the broken line in FIG. 7, the control unit 40 controls the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13, or the return fuel. Increase the amount. As a result, the heated return fuel is introduced (or increased) into the fuel tank FT, so that the fuel in the fuel tank FT is heated. The introduction (or increase) of the return fuel into the fuel tank FT is continuously performed during the purge execution with the engine ENG being driven. As a result, the fuel in the fuel tank FT is heated and the pressure in the fuel tank FT (tank internal pressure) is lowered.

After that, when the temperature inside the tank becomes equal to or higher than the predetermined temperature (step S46: YES), the control unit 40 stops the fuel pump FP (or lowers the rotation speed of the fuel pump FP) and enters the fuel tank FT of the return fuel. (Or reduce the amount of return fuel), and end the heating of the fuel in the fuel tank FT (step S47). Then, when the engine ENG is stopped (OFF) (step S48: YES) and the IG is turned OFF (step S49: YES), the control unit 40 determines whether or not the OBD condition is satisfied (step S50). .. If the engine ENG is not stopped (S48: NO), the process returns to S44. If the IG is not turned off (S49: NO), the process returns to the process of S42.

When the OBD condition is satisfied (S50: YES), the control unit 40 closes the atmosphere release valve 27 and the purge control valve 23 (step S51). As a result, the fuel tank FT and the canister 21 are sealed. Then, since the fuel in the fuel tank FT is sealed in a heated state, the temperature in the fuel tank FT decreases toward the outside air temperature, and the inside of the fuel tank FT becomes a negative pressure.

Then, in the control unit 40, the pressure change (negative differential pressure) of the tank internal pressure from the time when the fuel tank FT and the canister 21 are sealed is equal to or more than a certain value, that is, a predetermined negative pressure (for example, -3 kPa) in the fuel tank FT. Is determined based on the detected value of the pressure sensor 31 (step S52). At this time, if the pressure change is equal to or higher than a certain level (S52: YES), the control unit 40 executes a leak inspection (step S53). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and determines whether or not there is a leak in the evaporated fuel treatment device 1A. The presence or absence of this leak is determined by a known method. Since the leak inspection is performed by the negative pressure in this way, it is possible to prevent the evaporated fuel adsorbed on the canister 21 from being released during the leak inspection. The judgment value is corrected by the temperature inside the tank.

By performing control based on the control chart shown in FIG. 8, an example of the control time chart as shown in FIGS. 9A, 9B, and 9C is implemented. As shown in FIGS. 9A, 9B and 9C, when the engine ENG is started at time T10 and the purge condition is satisfied at time T11, purging is executed and the fuel tank FT with return fuel is used. Fuel heating is carried out. At this time, the heating of the fuel is controlled so that the temperature inside the tank becomes equal to or higher than the predetermined temperature. Then, when the engine ENG is stopped at time T12, the pressure inside the tank decreases, and at time T13, the pressure change in the fuel tank FT becomes equal to or higher than a certain level. After that, a leak check is executed at regular intervals from time T14 to T18. At this time, if the tank internal pressure is within the range of the determination value shown by the broken line in FIG. 9A, it is determined that there is no leak, and if it is outside the range of the determination value, it is determined that there is a leak.

As described above, in the present embodiment, when the temperature detected by the temperature sensor 32 is equal to or lower than the predetermined temperature, the fuel heated by the high-pressure pump 14 is returned to the fuel tank FT via the return passage 13 and returned to the fuel tank FT. Heat the fuel inside. After that, when the temperature detected by the temperature sensor 32 becomes equal to or higher than a predetermined temperature, the fuel pump FP is stopped to finish heating the fuel in the fuel tank FT. Then, the purge control valve 23 and the air release valve 27 are operated to seal the fuel tank FT, and a predetermined negative pressure is generated in the fuel tank FT to perform a leak inspection.

<Control content of positive pressure OBD>
Next, the control when the positive pressure OBD is performed in the evaporated fuel processing apparatus 1A will be described with reference to FIG. First, in the control unit 40, when the IG is turned on (step S60), the engine ENG is driven (ON) (step S61), and the engine ENG is stopped (OFF) after the warm-up of the engine ENG is completed (step S61). Step S62), it is determined whether or not the OBD condition is satisfied (step S63).

At this time, if the OBD condition is satisfied (S63: YES), the control unit 40 closes the atmosphere release valve 27 and the purge control valve 23 (step S64). As a result, the fuel tank FT and the canister 21 are sealed. Then, the control unit 40 confirms the remaining amount of fuel in the fuel tank FT from the liquid level sensor 30 (step S65). Further, the control unit 40 confirms the outside air temperature from the intake air temperature sensor (step S66) and confirms the temperature inside the tank from the temperature sensor 32 (step S67).

Then, the control unit 40 returns the return fuel to the fuel tank FT, which is necessary to generate a positive pressure for performing a leak inspection in the fuel tank FT based on the remaining fuel amount, the outside air temperature, and the temperature inside the tank. The amount is set (step S68). The set amount of the return fuel is basically set based on the remaining amount of fuel, and is corrected by the outside air temperature and the temperature inside the tank. In other words, the smaller the remaining fuel amount, the smaller the set amount of return fuel is set, and when the temperature is high, the set amount of return fuel is corrected to decrease, and when the temperature is low, the set amount of return fuel is corrected. It is corrected so that the set amount of the amount increases.

Then, the control unit 40 starts heating the fuel in the fuel tank FT (step S69). That is, as shown by the broken line in FIG. 7, the control unit 40 controls the drive of the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13. As a result, the heated return fuel is introduced into the fuel tank FT, so that the fuel in the fuel tank FT is heated. If the OBD condition is not satisfied (S63: NO), this processing routine is terminated.

After that, when the return fuel amount reaches the set amount, that is, when the set amount of return fuel is introduced (returned) into the fuel tank FT (step S70: YES), the control unit 40 stops the fuel pump FP. Then, the introduction of the return fuel into the fuel tank FT is stopped, and the heating of the fuel in the fuel tank FT is completed (step S71). When the heating of the fuel in the fuel tank FT is completed, the control unit 40 increases the pressure change (positive differential pressure) of the tank internal pressure from the time when the fuel tank FT and the canister 21 are sealed to a certain level or more, that is, in the fuel tank FT. Whether or not a predetermined positive pressure (for example, 3 kPa) is generated is determined based on the detected value of the pressure sensor 31 (step S72).

At this time, if the pressure change is equal to or higher than a certain level (S72: YES), the control unit 40 executes a leak inspection (step S73). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and determines whether or not there is a leak in the evaporated fuel treatment device 1. The presence or absence of this leak is determined by a known method. If the pressure change is not equal to or higher than a certain level (S72: NO), this processing routine is terminated without performing a leak inspection.

By performing control based on the control chart shown in FIG. 10, an example of the control time chart as shown in FIGS. 11A, 11B, and 11C is implemented. As shown in FIGS. 11A, 11B, and 11C, the engine ENG is started at time T10, and when the purge condition is satisfied at time T11, purging is executed. At this time, there is almost no change in the tank internal pressure, but the tank internal temperature is heated by the heat from the exhaust pipe or the like. Then, when the engine ENG is stopped at time T12, the fuel in the fuel tank FT is heated by the return fuel. Then, the tank internal pressure will increase. Then, at time T13, the return fuel amount reaches the set amount and the fuel heating is completed. At this time, the pressure change in the fuel tank FT is above a certain level. Therefore, the leak check is executed at regular intervals from time T14 to T16. At this time, if the tank internal pressure is within the range of the determination value shown by the broken line in FIG. 11A, it is determined that there is no leak, and if it is outside the range of the determination value, it is determined that there is a leak.

As described above, in the present embodiment, after the purge control valve 23 and the atmosphere release valve 27 are operated to seal the fuel tank FT, the fuel heated by the high-pressure pump 14 is returned to the fuel tank FT via the return passage 13. The fuel in the fuel tank FT is heated. After that, when the return fuel amount reaches the set amount, the fuel pump FP is stopped and the heating of the fuel in the fuel tank FT is completed. In this way, a predetermined positive pressure is generated in the fuel tank FT to perform a leak inspection.

As described above, according to the evaporative fuel treatment device 1A of the present embodiment, the same effect as that of the first embodiment can be obtained without heating the fuel in the fuel tank FT more than necessary. Further, since the rotation speed and the driving time of the fuel pump FP can be reduced, the power consumption can be reduced and the fuel consumption can be improved.

[Third Embodiment]
Subsequently, the evaporative fuel processing apparatus of the third embodiment will be described with reference to FIG. The third embodiment illustrates a case where the present disclosure is applied to an evaporative fuel treatment device that employs a closed tank. Specifically, the evaporative fuel processing device 1B of the present embodiment includes a sealing valve 35 for sealing the fuel tank FT, as shown in FIG. That is, in the evaporative fuel processing device 1B of the present embodiment, the sealing valve 35 is provided in the vapor passage 24, and the blocking valve 35 closes to close the fuel tank FT. The opening and closing of the blocking valve 35 is controlled by the control unit 40. Then, the evaporated fuel treatment device 1B of the present embodiment can also perform negative pressure OBD control or positive pressure OBD control as in the first embodiment.

<Control contents of negative pressure OBD>
Therefore, first, the control when the negative pressure OBD is performed will be described with reference to FIG. Also in this embodiment, the fuel heated by the high-pressure pump 14 is returned to the fuel tank FT via the return passage 13 to heat the fuel in the fuel tank FT, and then a negative pressure is generated in the fuel tank FT to perform a leak inspection. I do.

Specifically, the control unit 40 performs negative pressure OBD control based on the control chart shown in FIG. That is, after the IG is turned on (step S81), the engine ENG is driven (ON) (step S82), and the purge condition is satisfied (step S83: YES), the control unit 40 has the tank internal pressure near the atmospheric pressure. It is determined whether or not there is (step S84). At this time, the pressure in the fuel tank FT (tank internal pressure) is lowered by executing the purge.

Then, when the tank internal pressure is near the atmospheric pressure (S84: YES), the control unit 40 turns on (opens) the blocking valve 35 (step S85) and starts heating the fuel in the fuel tank FT. (Step S86). That is, as shown by the broken line in FIG. 12, the control unit 40 controls the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13. If the tank internal pressure is not near the atmospheric pressure (S84: NO), the process proceeds to S90 described later.

After that, when the engine ENG is stopped (OFF) (step S87: YES), the control unit 40 stops the fuel pump FP, stops the introduction of the return fuel into the fuel tank FT, and enters the fuel tank FT. The heating of the fuel of (step S88) is completed. Next, the control unit 40 turns off (closes) the blocking valve 35 (step S89). Then, when the IG is turned off (step S90: YES), the control unit 40 determines whether or not the OBD condition is satisfied (step S91). If the IG remains ON (S90: NO), the process returns to the process of S82, and the processes of S82 to S90 are repeated.

When the OBD condition is satisfied (S91: YES), the control unit 40 changes the pressure in the fuel tank FT (tank internal pressure) from the time when the closing valve 35 is closed and the fuel tank FT is closed (negative). Whether or not the differential pressure) is above a certain level, that is, whether or not a predetermined negative pressure (for example, -3 kPa) is generated in the fuel tank FT is determined based on the detected value of the pressure sensor 31 (step S92). At this time, if the pressure change is equal to or higher than a certain level (S92: YES), the control unit 40 executes a leak inspection in the fuel tank FT (step S93). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and the evaporative fuel processing device 1B determines whether or not the leak in the fuel tank FT occurs. Judge the presence or absence. The presence or absence of this leak is determined by a known method.

After that, the control unit 40 closes the air release valve 27 and the purge control valve 23 (step S94), and turns on (opens) the blockade valve 35 (step S95). As a result, the inside of the canister 21, the purge passage 22, and the vapor passage 24 is sealed. Then, the control unit 40 executes a leak inspection of each pipe of the canister 21, the purge passage 22, and the vapor passage 24 (step S96). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and in the evaporated fuel processing device 1B, the canister 21 and the purge passage 22 and It is determined whether or not there is a leak in each pipe of the vapor passage 24. The presence or absence of this leak is determined by a known method.

<Control content of positive pressure OBD>
Next, the control when the positive pressure OBD is performed in the evaporated fuel processing apparatus 1B will be described with reference to FIG. In this case, after the fuel tank FT is sealed, the fuel heated by the high-pressure pump 14 is returned to the fuel tank FT via the return passage 13 to heat the fuel in the fuel tank FT, and the fuel in the fuel tank FT is positive. Perform leak inspection by generating pressure.

Specifically, the control unit 40 performs positive pressure OBD control based on the control chart shown in FIG. That is, when the IG is turned on (step S100) and the engine ENG is driven (ON) (step S101: YES), the control unit 40 turns on (opens) the blocking valve 35 (step S102). When the engine ENG is not driven (S101: NO), the control unit 40 determines whether or not the IG is OFF (step S115). At this time, if IG is OFF (S115: YES), the process proceeds to S105. On the other hand, if IG is not OFF (S115: NO), the process returns to S100.

Then, when the engine ENG is stopped (OFF) after the warm-up of the engine ENG is completed (step S103), the control unit 40 turns off (closes) the blocking valve 35 (step S104), and sets the OBD condition. It is determined whether or not it is satisfied (step S105). At this time, if the OBD condition is satisfied (S105: YES), the control unit 40 determines whether or not the tank internal pressure is near the atmospheric pressure (step S106). If the OBD condition is not satisfied (S105: NO), this processing routine is terminated.

When the tank internal pressure is near atmospheric pressure (S106: YES), the control unit 40 starts heating the fuel in the fuel tank FT (step S107). That is, as shown by the broken line in FIG. 12, the control unit 40 controls the drive of the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13. As a result, the heated return fuel is introduced into the fuel tank FT, so that the fuel in the fuel tank FT is heated. If the tank internal pressure is not near the atmospheric pressure (S106: NO), the process proceeds to S111, which will be described later. Then, when the return fuel is introduced (returned) into the fuel tank FT by a predetermined amount (step S108: YES), the control unit 40 stops the fuel pump FP and the fuel tank of the return fuel. The introduction into the FT is stopped, and the heating of the fuel in the fuel tank FT is finished (step S109).

When the heating of the fuel in the fuel tank FT is completed, the control unit 40 closes the sealing valve 35 and the pressure change (positive differential pressure) of the tank internal pressure from the time when the fuel tank FT is closed is more than a certain value, that is, Whether or not a predetermined positive pressure (for example, 3 kPa) is generated in the fuel tank FT is determined based on the detected value of the pressure sensor 31 (step S110). At this time, if the pressure change is equal to or higher than a certain level (S110: YES), the control unit 40 executes a leak inspection in the fuel tank FT (step S111). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and the evaporative fuel processing device 1B determines whether or not the leak in the fuel tank FT occurs. Judge the presence or absence. The presence or absence of this leak is determined by a known method.

After that, the control unit 40 closes the air release valve 27 and the purge control valve 23 (step S112), and turns on (opens) the blockade valve 35 (step S113). As a result, the inside of the canister 21, the purge passage 22, and the vapor passage 24 is sealed. Then, the control unit 40 executes a leak inspection of each pipe of the canister 21, the purge passage 22, and the vapor passage 24 (step S114). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and in the evaporated fuel processing device 1B, the canister 21 and the purge passage 22 and It is determined whether or not there is a leak in each pipe of the vapor passage 24. The presence or absence of this leak is determined by a known method.

<Control content of modified example of positive pressure OBD>
In this embodiment as well, a modified example of positive pressure OBD can be applied as in the first embodiment. That is, in this modification, after starting heating of the fuel in the fuel tank FT by the return fuel, when a predetermined positive pressure (for example, 3 kPa) is generated in the fuel tank FT, the fuel in the fuel tank FT The heating can be completed to prevent unnecessary fuel heating. Therefore, a modified example of the positive pressure OBD will be described with reference to FIG.

In this modification, the control unit 40 performs positive pressure OBD control based on the control chart shown in FIG. That is, when the IG is turned on (step S120) and the engine ENG is driven (ON) (step S121: YES), the control unit 40 turns on (opens) the blocking valve 35 (step S122). When the engine ENG is not driven (S121: NO), the control unit 40 determines whether or not the IG is OFF (step S134). At this time, if IG is OFF (S134: YES), the process proceeds to S125. On the other hand, if IG is not OFF (S134: NO), the process returns to S120.

Then, when the engine ENG is stopped (OFF) after the warm-up of the engine ENG is completed (step S123), the control unit 40 turns off (closes) the blocking valve 35 (step S124), and sets the OBD condition. It is determined whether or not it is satisfied (step S125). At this time, if the OBD condition is satisfied (S125: YES), the control unit 40 determines whether or not the tank internal pressure is near the atmospheric pressure (step S126). If the OBD condition is not satisfied (S125: NO), this processing routine is terminated.

When the tank internal pressure is near the atmospheric pressure (S126: YES), the control unit 40 starts heating the fuel in the fuel tank FT (step S127). That is, as shown by the broken line in FIG. 12, the control unit 40 controls the drive of the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13. As a result, the heated return fuel is introduced into the fuel tank FT, so that the fuel in the fuel tank FT is heated. If the tank internal pressure is not near the atmospheric pressure (S126: NO), the process proceeds to S130, which will be described later.

After that, the control unit 40 closes the sealing valve 35 to seal the fuel tank FT, and the pressure change (positive differential pressure) in the tank internal pressure is equal to or more than a certain value, that is, a predetermined positive pressure (positive differential pressure) in the fuel tank FT. For example, when 3 kPa) occurs (step S128: YES), the fuel pump FP is stopped, the introduction of the return fuel into the fuel tank FT is stopped, and the heating of the fuel in the fuel tank FT is completed (step S129). ).

When the heating of the fuel in the fuel tank FT is completed, the control unit 40 executes a leak inspection in the fuel tank FT (step S130). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and the evaporative fuel processing device 1B determines whether or not the leak in the fuel tank FT occurs. Judge the presence or absence. The presence or absence of this leak is determined by a known method.

After that, the control unit 40 closes the air release valve 27 and the purge control valve 23 (step S131), and turns on (opens) the blockade valve 35 (step S132). As a result, the inside of the canister 21, the purge passage 22, and the vapor passage 24 is sealed. Then, the control unit 40 executes a leak inspection of each pipe of the canister 21, the purge passage 22, and the vapor passage 24 (step S133). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and in the evaporated fuel processing device 1B, the canister 21 and the purge passage 22 and It is determined whether or not there is a leak in each pipe of the vapor passage 24. The presence or absence of this leak is determined by a known method.

As described above, according to the evaporated fuel treatment device 1B of the present embodiment, the same effect as that of the first embodiment can be obtained. Further, according to the evaporative fuel treatment device 1B of the present embodiment, since the sealing valve 35 is provided, the presence or absence of a leak in the fuel tank FT and the presence or absence of a leak in each pipe of the canister 21, the purge passage 22, and the vapor passage 24. It is possible to perform a highly accurate leak inspection that can determine and separately. Since the sealing valve 35 provided in the sealing tank system is used as the control valve for sealing the fuel tank FT, such a highly accurate leak inspection is performed while reducing the cost of the device. be able to.

[Fourth Embodiment]
Next, the evaporated fuel treatment apparatus of the fourth embodiment will be described with reference to FIG. The fourth embodiment has the same basic configuration as the third embodiment, but as shown in FIG. 16, a temperature sensor 32 for detecting the temperature inside the fuel tank FT (the temperature inside the tank) is provided. The point is different. That is, in the evaporated fuel processing apparatus 1C of the fourth embodiment, the temperature sensor 32 is arranged in the fuel tank FT. The evaporated fuel processing device 1C of the present embodiment can also perform negative pressure OBD control or positive pressure OBD control as in the third embodiment.

<Control contents of negative pressure OBD>
Therefore, first, the control when the negative pressure OBD is performed will be described with reference to FIG. First, in the control unit 40, when the ignition switch (IG) is turned on (step S141), the engine ENG is driven (ON) (step S142), and the purge condition is satisfied (step S143: YES), the control unit 40 Determines whether or not the tank internal pressure is near the atmospheric pressure (step S144). At this time, the pressure in the fuel tank FT (tank internal pressure) is lowered by executing the purge.

Then, when the tank internal pressure is near the atmospheric pressure (S144: YES), the control unit 40 turns on (opens) the blocking valve 35 (step S145), and the temperature inside the fuel tank FT (tank temperature). ) Is below the predetermined temperature (step S146). If the tank internal pressure is not near the atmospheric pressure (S144: NO), the process proceeds to S152, which will be described later. At this time, if the temperature inside the tank is equal to or lower than the predetermined temperature (S146: YES), the control unit 40 starts heating the fuel in the fuel tank FT as shown by the broken line in FIG. 16 (step S147). That is, the control unit 40 controls the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13, or increases the amount of the return fuel. As a result, the heated return fuel is introduced (or increased) into the fuel tank FT, so that the fuel in the fuel tank FT is heated. The introduction (or increase) of the return fuel into the fuel tank FT is continuously performed during the purge execution with the engine ENG being driven.

After that, when the temperature inside the tank becomes equal to or higher than the predetermined temperature (step S148: YES), the control unit 40 stops the fuel pump FP (or lowers the rotation speed of the fuel pump FP) and enters the fuel tank FT of the return fuel. (Or reduce the amount of return fuel), and end the heating of the fuel in the fuel tank FT (step S149). Then, when the engine ENG is stopped (OFF) (step S150: YES), the control unit 40 turns off (closes) the blocking valve 35 (step S151).

Then, when the IG is turned off (step S152: YES), the control unit 40 determines whether or not the OBD condition is satisfied (step S153). If the IG remains ON (S153: NO), the process returns to the process of S142, and the processes of S142 to S151 are repeated.

When the OBD condition is satisfied (S153: YES), the control unit 40 changes the pressure (negative) of the pressure in the fuel tank FT (tank internal pressure) from the time when the closing valve 35 is closed and the fuel tank FT is closed. Whether or not the differential pressure) is above a certain level, that is, whether or not a predetermined negative pressure (for example, -3 kPa) is generated in the fuel tank FT is determined based on the detected value of the pressure sensor 31 (step S154). At this time, if the pressure change is equal to or higher than a certain level (S154: YES), the control unit 40 executes a leak inspection in the fuel tank FT (step S155). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and the evaporative fuel processing device 1C determines whether or not the leak in the fuel tank FT occurs. Judge the presence or absence. The presence or absence of this leak is determined by a known method.

After that, the control unit 40 closes the air release valve 27 and the purge control valve 23 (step S156), and turns on (opens) the blockade valve 35 (step S157). As a result, the inside of the canister 21, the purge passage 22, and the vapor passage 24 is sealed. Then, the control unit 40 executes a leak inspection of each pipe of the canister 21, the purge passage 22, and the vapor passage 24 (step S158). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and in the evaporated fuel processing device 1C, the canister 21 and the purge passage 22 and It is determined whether or not there is a leak in each pipe of the vapor passage 24. The presence or absence of this leak is determined by a known method.

<Control content of positive pressure OBD>
Next, the control when the positive pressure OBD is performed in the evaporated fuel processing apparatus 1C will be described with reference to FIG. In this case, after the fuel tank FT is sealed, the fuel heated by the high-pressure pump 14 is returned to the fuel tank FT via the return passage 13 to heat the fuel in the fuel tank FT, and the fuel in the fuel tank FT is positive. Perform leak inspection by generating pressure.

Specifically, the control unit 40 performs positive pressure OBD control based on the control chart shown in FIG. That is, when the IG is turned on (step S160) and the engine ENG is driven (ON) (step S161: YES), the control unit 40 turns on (opens) the blocking valve 35 (step S162). When the engine ENG is not driven (S161: NO), the control unit 40 determines whether or not the IG is OFF (step S179). At this time, if IG is OFF (S179: YES), the process proceeds to S165. On the other hand, if IG is not OFF (S179: NO), the process returns to S160.

Then, when the engine ENG is stopped (OFF) after the warm-up of the engine ENG is completed (step S163), the control unit 40 turns off (closes) the blocking valve 35 (step S164) to set the OBD condition. It is determined whether or not it is satisfied (step S165). At this time, if the OBD condition is satisfied (S165: YES), the control unit 40 determines whether or not the tank internal pressure is near the atmospheric pressure (step S166). If the OBD condition is not satisfied (S165: NO), this processing routine is terminated.

When the tank internal pressure is near atmospheric pressure (S166: YES), the control unit 40 confirms the remaining amount of fuel in the fuel tank FT from the liquid level sensor 30 (step S167). Further, the control unit 40 confirms the outside air temperature from the intake air temperature sensor (step S168) and confirms the temperature inside the tank from the temperature sensor 32 (step S169).

Then, the control unit 40 returns the return fuel to the fuel tank FT, which is necessary to generate a positive pressure for performing a leak inspection in the fuel tank FT based on the remaining fuel amount, the outside air temperature, and the temperature inside the tank. The amount is set (step S170). The set amount of the return fuel is basically set based on the remaining amount of fuel, and is corrected by the outside air temperature and the temperature inside the tank. In other words, the smaller the remaining fuel amount, the smaller the set amount of return fuel is set, and when the temperature is high, the set amount of return fuel is corrected to decrease, and when the temperature is low, the set amount of return fuel is corrected. It is corrected so that the set amount of the amount increases.

Then, the control unit 40 starts heating the fuel in the fuel tank FT (step S171). That is, as shown by the broken line in FIG. 16, the control unit 40 controls the drive of the fuel pump FP and starts returning the fuel heated by the high pressure pump 14 to the fuel tank FT via the return passage 13. As a result, the heated return fuel is introduced into the fuel tank FT, so that the fuel in the fuel tank FT is heated.

After that, when the return fuel amount reaches the set amount, that is, when the set amount of return fuel is introduced (returned) into the fuel tank FT (step S172: YES), the control unit 40 stops the fuel pump FP. Then, the introduction of the return fuel into the fuel tank FT is stopped, and the heating of the fuel in the fuel tank FT is completed (step S173).

When the heating of the fuel in the fuel tank FT is completed, the control unit 40 closes the sealing valve 35 and the pressure change (positive differential pressure) of the tank internal pressure from the time when the fuel tank FT is closed is more than a certain value, that is, Whether or not a predetermined positive pressure (for example, 3 kPa) is generated in the fuel tank FT is determined based on the detected value of the pressure sensor 31 (step S174). At this time, if the pressure change is equal to or higher than a certain level (S174: YES), the control unit 40 executes a leak inspection in the fuel tank FT (step S175). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and the evaporative fuel processing device 1C determines whether or not the leak in the fuel tank FT occurs. Judge the presence or absence. The presence or absence of this leak is determined by a known method.

After that, the control unit 40 closes the air release valve 27 and the purge control valve 23 (step S176), and turns on (opens) the blockade valve 35 (step S177). As a result, the inside of the canister 21, the purge passage 22, and the vapor passage 24 is sealed. Then, the control unit 40 executes a leak inspection of each pipe of the canister 21, the purge passage 22, and the vapor passage 24 (step S178). That is, at regular intervals, the control unit 40 determines whether or not the tank internal pressure detected by the pressure sensor 31 is within the range of the determination value, and in the evaporated fuel processing device 1C, the canister 21 and the purge passage 22 and It is determined whether or not there is a leak in each pipe of the vapor passage 24. The presence or absence of this leak is determined by a known method.

As described above, according to the evaporative fuel treatment device 1C of the present embodiment, even when the closed tank system is adopted, the same effect as that of the third embodiment can be obtained without heating the fuel in the fuel tank FT more than necessary. Obtainable.

[Fifth Embodiment]
Finally, the evaporative fuel processing apparatus of the fifth embodiment will be described with reference to FIG. The fifth embodiment has the same basic configuration as the first embodiment, but as shown in FIG. 19, a bypass passage 16 for returning fuel to the fuel tank FT without passing through the high-pressure pump 14 which is a heat receiving portion. The difference is that a switching valve 17 for opening the bypass passage 16 is provided. The switching valve 17 is an example of the "opening / closing valve" of the present disclosure, and is a three-way valve in the present embodiment.

In the evaporated fuel processing device 1D of the present embodiment, a bypass passage 16 connecting the fuel passage 12 and the return passage 13 is provided in the fuel tank FT, and the bypass passage 16 is opened or shut off by the switching valve 17. Then, the pressure regulator 15 is arranged in the fuel tank FT via the switching valve 17.

The switching valve 17 is connected to the control unit 40, and the bypass passage 16 is opened or shut off by being ON / OFF controlled by the control unit 40. In the present embodiment, when the control unit 40 determines that heating of the fuel in the fuel tank is unnecessary (for example, when the return fuel amount reaches a predetermined amount), the switching valve 17 is turned on and bypassed. The passage 16 is opened, and the fuel supplied from the inside of the fuel tank FT to the fuel passage 12 by the fuel pump FP is returned to the fuel tank FT via the bypass passage 16. When the switching valve 17 is OFF, the bypass passage 16 is shut off, and the fuel supplied from the fuel tank FT to the fuel passage 12 by the fuel pump FP passes through the high pressure pump 14 and passes through the return passage 13. Is returned to the fuel tank FT.

In the evaporated fuel processing apparatus 1D of the present embodiment as described above, when it is not necessary to heat the fuel in the fuel tank FT, the switching valve 17 is turned on by the control unit 40 and the bypass passage 16 is opened. As shown by the broken line, the fuel is returned into the fuel tank FT through the bypass passage 16 without passing through the high pressure pump 14. Therefore, it is possible to prevent the heated return fuel from being returned to the fuel tank FT. As a result, it is possible to prevent the fuel in the fuel tank FT from being heated more than necessary.

In the present embodiment, the pressure regulator 15, the bypass passage 16 and the switching valve 17 are arranged in the fuel tank FT, but the pressure adjusting device 15, the bypass passage 16 and the switching valve 17 are arranged in the fuel tank. It is not limited to within the FT. However, by arranging them in the fuel tank FT as in the present embodiment, these can be integrated with the fuel pump module, so that the assembly cost can be reduced.

It should be noted that the above-described embodiment is merely an example and does not limit the present disclosure in any way, and it goes without saying that various improvements and modifications can be made without departing from the gist thereof. For example, in the above embodiment, the engine system including the high pressure pump 14 is illustrated, but the present disclosure can be applied to the engine system not provided with the high pressure pump 14. In this case, for example, as shown in FIG. 20, a delivery pipe 18 is provided, the fuel is heated by receiving heat from the engine ENG in the delivery pipe 18, and the heated fuel is passed through the return passage 13 to the fuel tank. Returned to FT (see dashed line in FIG. 20). The delivery pipe 18 is an example of the “heat receiving portion from the internal combustion engine” of the present disclosure. Although the device in which the delivery pipe 18 is provided is illustrated in the first embodiment, the delivery pipe 18 can also be provided in the second to fifth embodiments without providing the high pressure pump 14. ..

Further, in the first to fourth embodiments, the pressure regulator 15 is provided near the engine ENG, but the pressure regulator 15 may be provided in the middle of the return passage 13. Therefore, for example, as shown in FIG. 21, it may be provided in the fuel tank FT as in the fifth embodiment. By doing so, the pressure regulator 15 can be integrated with the fuel pump module, so that the assembly cost can be reduced.

1 Evaporated fuel processing device 12 Fuel passage 13 Return passage 14 High pressure pump 15 Pressure regulator 21 Canister 23 Purge control valve 27 Air release valve 30 Liquid level sensor 31 Pressure sensor 32 Temperature sensor 35 Block valve 40 Control unit ENG engine FP Fuel pump FT Fuel tank

Claims

A fuel tank for storing fuel, a fuel pump for pumping fuel in the fuel tank to the internal combustion engine via a fuel passage, a canister for storing evaporated fuel sent from the fuel tank via a vapor passage, and the fuel. A return passage that returns a part or all of the fuel pumped by the pump to the fuel tank, at least two control valves that seal the fuel tank, a pressure sensor that detects the pressure in the fuel tank, and the fuel pump. And a control unit for controlling the control valve, in an evaporative fuel processing apparatus.
The fuel passage or the return passage includes a heat receiving portion from an internal combustion engine.
After the warm-up of the internal combustion engine is completed, the control unit drives the fuel pump to return the fuel heated by the heat receiving unit to the fuel tank via the return passage, and the fuel in the fuel tank is returned. An evaporative fuel treatment apparatus characterized in that after heating to generate a differential pressure in the fuel tank, a leak inspection is performed based on a change in a pressure value detected by the pressure sensor.
In the evaporated fuel treatment apparatus according to claim 1,
After operating the control valve to seal the fuel tank, the control unit returns the fuel heated by the heat receiving unit to the fuel tank via the return passage to heat the fuel in the fuel tank. , An evaporative fuel treatment apparatus characterized in that a positive pressure is generated in the fuel tank to perform a leak inspection.
In the evaporated fuel treatment apparatus according to claim 1,
The control unit returns the fuel heated by the heat receiving unit to the fuel tank via the return passage to heat the fuel in the fuel tank, and then operates the control valve to seal the fuel tank. An evaporative fuel processing apparatus characterized in that a negative pressure is generated in the fuel tank to perform a leak inspection.
In the evaporated fuel treatment apparatus according to claim 2.
The control unit is an evaporative fuel processing apparatus characterized in that the amount of return fuel returned to the fuel tank is changed based on the amount of fuel in the fuel tank.
In the evaporated fuel treatment apparatus according to claim 2.
The control unit is an evaporative fuel processing apparatus characterized in that when the pressure detected by the pressure sensor becomes equal to or higher than a predetermined pressure, the fuel pump is stopped to end the heating of the fuel in the fuel tank. ..
In the evaporated fuel treatment apparatus according to claim 3.
The control unit returns the fuel heated by the heat receiving unit to the fuel tank via the return passage while the purge in which the evaporated fuel stored in the canister is supplied to the internal combustion engine is being executed. An evaporative fuel treatment apparatus characterized in that when the fuel in the fuel tank is heated and the internal combustion engine is stopped, the fuel pump is stopped to end the heating of the fuel in the fuel tank.
In the evaporated fuel treatment apparatus according to claim 3.
A temperature sensor for detecting the temperature inside the fuel tank is provided.
The control unit is an evaporative fuel processing apparatus characterized in that when the temperature detected by the temperature sensor is equal to or higher than a predetermined temperature, the fuel pump is stopped to end the heating of the fuel in the fuel tank. ..
In any one of the evaporated fuel treatment devices according to claims 1 to 7.
A bypass passage that returns fuel to the fuel tank without passing through the heat receiving section,
It is equipped with an on-off valve that opens and closes the bypass passage.
The control unit is an evaporative fuel processing device, which controls the on-off valve to open the bypass passage when it is not necessary to heat the fuel in the fuel tank.
In any one of the evaporated fuel treatment devices according to claims 1 to 8.
An evaporative fuel processing apparatus characterized in that the return passage is provided with a pressure regulator that regulates the pressure of the fuel in the passage so that the pressure does not rise above a certain level.
In any one of the evaporated fuel treatment devices according to claims 1 to 9.
In the case of a closed tank system including a closed valve for sealing the fuel tank, the evaporative fuel treatment device is characterized in that the closed valve is used as one of the control valves.