JPH08121279A - Fuel evaporation preventing device - Google Patents

Abstract

PURPOSE: To prevent emission of fuel evaporative gas from a fuel tank in oil feeding. CONSTITUTION: When an oil feeding switch 53 is operated prior to oil feeding, a solenoid valve 42 is opened under control of an electronic control unit 21, and at the same time, a compressor 23 is operated, so that fuel evaporative gas inside a fuel tank is fed into a reservoir 22 via pipes 31, 32. Afterward, if a fuel tank internal pressure detected by means of a pressure sensor 51 lowers below the atmospheric pressure, the solenoid valve 42 is closed, while operation of the compressor 23 is stopped, and then, a filler lid 12 is opened, so that oil feeding is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel transpiration prevention device, and more particularly to a fuel transpiration prevention device which can prevent the emission of fuel evaporative gas during refueling.

[0002]

2. Description of the Related Art Generally, automobiles emit harmful substances such as carbon monoxide, nitrogen oxides, and hydrocarbons. For example, unburned HC gas contained in blow-by gas or exhaust gas is discharged to the atmosphere as hydrocarbon (HC),
Further, raw gasoline (fuel evaporative gas) evaporated in the fuel tank or the like is released to the atmosphere as HC. Therefore, an automobile is equipped with a device for suppressing the emission of harmful substances, such as an exhaust gas purification device and a fuel evaporation prevention device.

The fuel transpiration prevention device prevents the emission of fuel evaporative emission to the atmosphere, and typically comprises a canister having activated carbon for adsorbing HC. The canister is provided with an introduction port communicating with the fuel tank, an exhaust port communicating with the intake pipe of the engine, and a vent port opening to the atmosphere. This type of canister storage type fuel evaporation preventive device introduces fuel evaporative gas (HC) in a fuel tank into a canister and adsorbs it to activated carbon in the canister when the engine is stopped. In addition, this system causes intake air negative pressure generated in the intake pipe due to subsequent engine operation to act on the exhaust port to introduce purge air from the vent port, and separates HC adsorbed on the activated carbon from the activated carbon by the purge air. Then, the separated HC is discharged to the intake pipe together with the purge air. HC discharged to the intake pipe
The (fuel evaporative gas) burns in the cylinder of the engine together with the air-fuel mixture, thereby preventing the fuel evaporative gas from being discharged to the atmosphere.

[0004]

However, when the engine is stopped, the fuel vapor adsorbed on the canister cannot be burnt in the engine. Therefore, when the engine is stopped for a long time due to parking, etc. When the temperature is high or the vehicle is exposed to direct sunlight, the amount of fuel evaporative emission in the fuel tank may exceed the capacity limit of the canister. In this case, the fuel evaporative emission is released into the atmosphere to promote air pollution.
Further, when the refueling port of the fuel tank is opened for refueling, the fuel evaporative gas in the fuel tank is diffused into the atmosphere.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel transpiration preventing device which can prevent unnecessary emission of fuel evaporative emission from the fueling port of a fuel tank during refueling.

[0006]

According to one embodiment of the present invention, there is provided a fuel transpiration prevention device, a reservoir communicating with a fuel tank through a reserve passage, and a gas reservoir inside the reservoir for storing a gas in the fuel tank. To the side, a pressure sensor for detecting the internal pressure of the fuel tank, a compressor operating means for operating the compressor when the refueling command means operates, and a pressure within the set value within the fuel tank when the refueling command means operates. And a display means for performing a display operation in response to the fact that the pressure sensor detects that the change has occurred.

A fuel evaporation preventing apparatus according to another aspect of the present invention is a reservoir which is communicated with a fuel tank through a reserve passage, and a compressor which is interposed in the reserve passage and guides gas in the fuel tank to the reservoir side. A pressure sensor for detecting the internal pressure of the fuel tank, a filler lid opening / closing means for opening / closing the filler lid of the fuel tank, a compressor operating means for operating the compressor when the refueling command means operates, and a refueling command means for operating. It is characterized by comprising a lid opening / closing control means for outputting a command signal for opening the filler lid to the filler lid opening / closing means in response to the pressure sensor detecting that the pressure in the fuel tank has become equal to or lower than a set value. To do.

[0008]

In the fuel transpiration prevention apparatus according to one aspect of the present invention, when the refueling command means operates prior to refueling, the compressor is operated by the compressor operating means. By this compressor operation, the gas containing the fuel evaporative gas in the fuel tank is guided to the reservoir side through the reserve passage. Therefore, the internal pressure of the fuel tank gradually decreases.

After that, when the internal pressure of the fuel tank becomes a pressure equal to or lower than the set value, this is detected by the pressure sensor. Then, the display means responsive to the detection result performs a display operation to notify the driver or the like that the internal pressure of the fuel tank has become equal to or lower than the set pressure. Therefore, the driver or the like permits the refueling worker to open the refueling port of the fuel tank. Since the internal pressure of the fuel tank is equal to or lower than the set pressure, the fuel evaporative gas does not blow out from the fuel tank even if the fuel supply port is opened.

Also in the fuel transpiration prevention apparatus according to another aspect of the present invention, when the refueling command means is activated prior to refueling, the compressor is activated by the compressor activating means, and the gas containing the fuel evaporative emission gas in the fuel tank is removed. , And is guided to the reservoir side through the reserve passage, and the fuel tank internal pressure gradually decreases. When the pressure sensor detects that the internal pressure of the fuel tank has become equal to or lower than the set value, the lid opening / closing control means that responds to the detection result outputs a command signal to the filler lid opening / closing means, and responds to this command signal. The filler lid opening / closing means opens the filler lid of the fuel tank to enable fueling.

Since the internal pressure of the fuel tank is equal to or lower than the set pressure, even if the filler lid is opened, the fuel evaporative gas does not blow out from the fuel tank.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel transpiration prevention device according to a first embodiment of the present invention will be described below. Referring to FIG. 1, a branch end side of an intake manifold 2 is connected to each cylinder of the engine 1, and an air cleaner 4 is provided at an outer end of an intake pipe 3 connected to a collecting end side of the intake manifold 2. There is. A fuel injection valve (not shown) is arranged in the intake manifold 2 near the intake port of each cylinder.

The fuel tank 10 includes a filler duct 10a.
And a vent pipe 10b, and a filler duct 10a
A filler cap 10c is attached to the fuel filler port of the above, and the fuel filler port side of the duct is surrounded by a filler lid 12 which is opened and closed by a filler lid opening / closing drive unit 11 as a filler lid opening / closing means. Then, the filler cap 10c is removed, and the filler lid 1 is removed.
When 2 is opened, a refueling gun (not shown) for refueling the fuel tank 10 can be inserted into the filler duct 10a. Reference numeral 13 indicates a refueling end detection switch which responds to the attachment / detachment of the filler cap 10c to / from the refueling port.

A fuel pump 14 is arranged in the fuel tank 10, and a fuel filter 15 is provided on the suction side of the pump 14. Then, a part of the fuel discharged from the fuel pump 14 is supplied to each fuel injection valve via the fuel pipe 16 and the delivery pipe 17, and the rest of the fuel is connected to the delivery pipe 17 to the fuel regulator 1.
8 and the return pipe 19 to be returned to the fuel tank 10.

The fuel transpiration prevention device is attached to the fuel system having the above structure to prevent the emission of fuel evaporative emission from the fuel tank 10, and an electronic control unit (ECU) for controlling the operation of each part of the device. 21 is provided. Further, the fuel evaporation prevention device is provided in the fuel upper space 1 in the fuel tank 10.
0d and the intake manifold 2 the 1st pipe 3 which connects
1 and a second pipe 32 branched from the pipe 31, the second pipe 32 extends to the reservoir 22 for accumulating the fuel evaporative emission gas, and cooperates with the first pipe 31 to form the reservoir 22. A reserve passage communicating with the fuel tank 10 is formed.

In the middle of the first pipe 31, the fuel evaporative gas passing through the pipe 31 (more generally, a gas containing the fuel evaporative gas from the tank space 10d (hereinafter,
The same as the above)) is provided with a first electromagnetic opening / closing valve 41 for selectively allowing or blocking the inflow to the intake manifold 2. Further, in the middle of the second pipe 32, a second electromagnetic opening / closing valve 42 for allowing or blocking the flow of the fuel evaporative gas through the pipe 32, a compressor 23 for sending the fuel evaporative gas to the reservoir 22, And a canister 24 for adsorbing the fuel evaporative gas.

On the upstream side of the compressor 23, one end of a third pipe 33 is connected to the second pipe 32, and the other end of the third pipe 33 is connected to the intake pipe 3.
Then, a part of the air introduced into the intake pipe 3 via the air cleaner 4 is sent as purge air to the canister 24 by the compressor 23 via the third pipe 33, whereby the fuel evaporative gas adsorbed on the canister 24 is absorbed. Is removed (purged) from the canister 24. In the middle of the third pipe 33, there is provided a third pipe for allowing or blocking the inflow of purge air through the pipe 33.
A solenoid valve 43 is provided.

A fourth pipe 34 extending from the reservoir 22
Communicates with the first pipe 31 on the intake manifold 2 side with respect to the first solenoid valve 41, and discharges the fuel evaporative gas in the reservoir 22 to the intake manifold 2 via the fourth pipe 34 by the intake negative pressure. There is. In the middle of the fourth pipe 34, a fourth electromagnetic opening / closing valve 44 for allowing or blocking the inflow of the fuel evaporative gas through the pipe 34 into the intake manifold 2 is provided. The first to fourth solenoid valves 41 to 44 are, for example, normally open solenoid valves.

The fuel tank 10 has a tank space 1
A first pressure sensor 51 for detecting the pressure within 0d, that is, the fuel tank internal pressure is provided, and the reservoir 22 is provided with a second pressure sensor 52 for detecting the reservoir internal pressure. The electronic control unit 21 is composed of a central processing unit for executing a program for fuel transpiration prevention control, which will be described later, a memory storing the control program, an input / output circuit (all not shown), and the like. ~ Fourth
Solenoid valves 41-44, first and second pressure sensors 51, 52,
It is connected to the compressor 23, the filler lid opening / closing drive unit 11, the oil supply switch 53, the lamp drive unit 55, and the like. If necessary, a drive unit (not shown) is provided between the electronic control unit 21, each of the solenoid valves 41 to 44, and the compressor 23.

The refueling switch 53 is provided together with the display lamp 54 on, for example, an instrument panel (not shown). When the driver turns on the refueling switch 53 as refueling command means prior to refueling, the electronic control unit 21 is controlled. As will be described below, the fuel evaporation prevention control process during refueling is executed, and when the process is completed, the indicator lamp 5
4 indicates that refueling is possible.

As will be apparent from the following explanation of the operation, the electronic control unit 21 functions as a compressor operating means and a lid opening / closing control means, and the display lamp 54.
Also, it functions as a display unit in cooperation with the lamp driving unit 55. The operation of the fuel transpiration prevention device having the above-described configuration will be described below with reference to FIGS. 2 to 5.

Electronic control unit 21 of the fuel evaporation prevention device
Is in the operating state while the ignition key (not shown) is in the ON position, and until at least a predetermined period (a time sufficiently longer than the maximum refueling time) has elapsed since the ignition key was turned off, The main routine (FIG. 2) of the fuel evaporation prevention control program is executed at a predetermined cycle.

In the main routine, the electronic control unit 21 determines whether the operation of the engine 1 is stopped by determining whether the ignition key is in the on position or the off position, for example (step). S1) If this determination result is negative, a subroutine (FIG. 3) for control during engine operation is executed (step S2).

On the other hand, when it is determined in step S1 that the operation of the engine 1 is stopped, the electronic control unit 2
1 determines whether the refueling switch 53 is turned on and the refueling command is sent based on the output from the switch 53 (step S3). If the result of this determination is negative, control at engine stop The subroutine for (FIG. 4) is executed (step S4). Step S3
When it is determined that the refueling command has been sent, the electronic control unit 21 executes a subroutine (FIG. 5) for control during refueling (step S5).

More specifically, when the engine is operating, in the subroutine of FIG. 3, the electronic control unit 21 sends a control output of, for example, L level to the first solenoid valve 41 to send the solenoid valve 4 to the solenoid valve 4.
1 (step S201), then the compressor 2
It is determined whether or not the compressor 23 is in operation by referring to the control output level to No. 3 (step S202).
Then, if the determination result is negative, it is further determined whether or not the internal pressure of the reservoir 22 is equal to or higher than the predetermined pressure based on the output from the second pressure sensor 52 (step S20).
3). Normally, the internal pressure of the reservoir is less than the predetermined pressure, so
The determination result in step S203 is negative. In this case, returning to the main routine of FIG. 2, if it is determined in step S1 that the operation of the engine 1 is not stopped,
The procedure returns to the subroutine of FIG. 3 again, and the first solenoid valve 41 is maintained in the open state. As a result, the fuel evaporative gas in the fuel tank 10 flows into the intake manifold 2 via the first pipe 31 due to the negative pressure of the intake air and burns in the cylinder of the engine 1. This causes the fuel evaporative gas during engine operation. Is prevented from being emitted from the fuel tank 10 into the atmosphere.

Thereafter, when it is determined in step S203 of the subroutine in FIG. 3 that the internal pressure of the reservoir has become equal to or higher than a predetermined pressure while the engine is operating, the electronic control unit 21 causes the fourth solenoid valve 44 to set, for example, L level. To output the control output of the solenoid valve 44 to open the solenoid valve 44 (step S20).
4) Next, the third solenoid valve 43 is similarly opened (step S205), the compressor 23 is further operated (step S206), and the process returns to the main routine. in this case,
When it is determined in step S1 of the main routine that the engine is not stopped and the process returns to the subroutine of FIG. 3, it is determined in step S202 of the same subroutine that the compressor 23 is operating, and then in step S207, the internal pressure of the reservoir is increased. It is determined that the pressure is equal to or higher than the predetermined pressure. Therefore, the third
The open states of the fourth solenoid valves 43 and 44 are maintained, and the operation of the compressor 23 continues.

As a result, a part of the air introduced into the intake pipe 3 via the air cleaner 4 is introduced into the third pipe 33, and further, the canister 24 is operated by the compressor 23.
Is supplied as purge air. As a result, the fuel evaporative gas adsorbed on the canister 24 is transferred to the canister 24.
And is sent into the reservoir 22 together with the purge air, and is further sucked into the intake manifold 2 through the fourth pipe 34 together with the fuel evaporative gas in the reservoir 22 by the intake negative pressure generated in the intake manifold 2. , Combustion in the engine 1 is reached.

As described above, the fuel vaporized gas in the reservoir 22 is sent to the engine 1 side, and the internal pressure of the reservoir is reduced. Then, when the reservoir internal pressure becomes less than the predetermined pressure, the determination result in step S207 becomes negative. In this case, the electronic control unit 21 sends, for example, an H level to the fourth solenoid valve 44 to close the solenoid valve 44 (step S
208) and similarly close the third solenoid valve 43 (step S2).
09) and stop the compressor 23 (step S2
10) Return to the main routine.

During engine operation, as described above, the first
The solenoid valve 41 is opened so that the fuel evaporative gas in the fuel tank 10 can always flow to the intake manifold 2, and the third and fourth solenoid valves 43 and 44 are opened and closed and the compressor 23 is operated as necessary. It is deactivated to maintain the internal pressure of the reservoir below a predetermined pressure, which allows the fuel evaporative gas to be smoothly sent from the fuel tank 10 to the reservoir 22 (described later) at the time of the next refueling.

When the engine is stopped, the subroutine of FIG. 4 corresponding to step S4 of the main routine (FIG. 2) is executed. In this subroutine, the electronic control unit 21 sends a control output of, for example, H level to the first solenoid valve 41 to close the solenoid valve 41 (step S401),
Next, the second to fourth electromagnetic valves 42 to 44 are sequentially closed (steps S402 to S404). As a result, the fuel tank 10 is in a hermetically sealed state, and the emission of the fuel evaporative gas from the fuel tank 10 to the atmosphere is prevented even when the engine is stopped.

At the time of refueling, step S of the main routine
The subroutine of FIG. 5 corresponding to 5 is executed. In this subroutine, the electronic control unit 21 sends the L-level control output to the second solenoid valve 42 to output the same.
Open (step S501), and then the compressor 23
Is operated (step S502). As a result, the fuel evaporative gas in the fuel tank 10 flows from the first pipe 31 to the second pipe.
It flows into the pipe 32, and then the second solenoid valve 42 in the open state.
Flows into the compressor 23 via. Further, the fuel evaporative gas is sent into the reservoir 22 via the canister 24 by the compressor 23. As a result, the fuel tank internal pressure gradually decreases. During this time, the electronic control unit 2
1 repeatedly determines whether or not the internal pressure of the fuel tank has become equal to or lower than a set pressure, for example, atmospheric pressure, based on the output indicating the internal pressure of the fuel tank from the first pressure sensor 51 (step S503).

If it is determined in step S503 that the internal pressure of the fuel tank has dropped below atmospheric pressure, the electronic control unit 2
1 sends a control output of, for example, H level to the lamp driving unit 55, thereby causing the display lamp 54 to be lit through the driving unit 55 (step S504). Next, the electronic control unit 21 closes the second electromagnetic valve 42 and stops the operation of the compressor 23 (step S5).
(05 and S506), for example, an H-level control output is sent to the filler lid opening / closing drive unit 11 to open the filler lid 12 via the drive unit 11 (step S507).

As described above, when the internal pressure of the fuel tank becomes equal to or lower than the atmospheric pressure, this is notified to the driver by lighting the lamp, and the filler lid 12 opens later. Therefore, the refueling worker attaches the filler cap 10c to the filler duct 10a.
And open the filler port. At this time, since the internal pressure of the fuel tank is equal to or lower than the atmospheric pressure, the fuel evaporative gas does not blow out from the fuel tank 10 even if the fuel supply port is opened. Next, the refueling worker inserts the refueling gun into the refueling port of the filler duct 10a to start refueling the fuel tank 10.

The electronic control unit 21 repeatedly determines whether or not the refueling is completed based on the output signal from the refueling end detection switch 13 (step S508). After that, refueling is completed and the refueling gun is pulled out from the refueling port,
Further, when the filler cap 10c is attached to the fuel filler port, the switch 13 outputs an output signal indicating the end of the fuel filler. When this refueling end signal is input, the electronic control unit 21 closes the filler lid 12 via the filler lid opening / closing drive unit 11 (step S509), and then turns off the display lamp 54 via the lamp drive unit 55. (Step S510). As a result, the subroutine of FIG. 5 ends, and the process returns to the main routine.

As described above, according to this embodiment, the emission of the fuel evaporative gas from the fuel tank 10 is prevented both during refueling and during periods other than refueling (when the engine is stopped and the engine is operating). FIG. 6 shows a subroutine for control during refueling in the modification of the first embodiment. This subroutine is step S from the subroutine of FIG.
505 to S507 and S509 are removed. The control at the time of refueling according to this modification can be performed by the fuel evaporation device having the same configuration as the device of FIG. 1, but the automatically opening and closing filler lids 11 and 12 are unnecessary. Also in this modification, prior to refueling, the fuel evaporative gas in the fuel tank 10 is sent into the reservoir 22 by the compressor 23, and when the fuel tank internal pressure becomes equal to or lower than the atmospheric pressure, the display lamp 54 lights up and this is notified to the driver or the like. To be done. Therefore, the driver or the like will allow the refueling worker to open the refueling port of the fuel tank, but at this time, since the internal pressure of the fuel tank is below atmospheric pressure, the fuel evaporative gas does not blow out from the fuel tank. .

A fuel transpiration preventing device according to a second embodiment of the present invention will be described below with reference to FIG. Compared with the device of the first embodiment (FIG. 1), the device of the present embodiment is mainly different in that the canister 24 shown in FIG. 1 is not provided, and FIG. 1 is shown in relation to this difference. Third pipe 33 and third
There is no element corresponding to the solenoid valve 43. Further, in this embodiment, the third pipe 33 corresponding to the fourth pipe 34 of FIG. 1 is used.
a is in communication with the first pipe 31 on the fuel tank 10 side with respect to the first solenoid valve 41, and the indicator lamp 54
The first point is that the lamp driving unit 55 is not provided.
Different from the embodiment. In the following description, the solenoid valve 43a corresponding to the fourth solenoid valve 44 in FIG. 1 will be referred to as the third solenoid valve. The rest of the configuration is the same as that of the first embodiment, so the explanation is omitted.

The operation of the apparatus shown in FIG. 7 will be briefly described below. The electronic control unit 21 of this device executes the same main routine (not shown) for fuel evaporation prevention control as shown in FIG. 2 at a predetermined cycle. And the control unit 2
As in the case of the first embodiment, when it is determined that the engine operation is not stopped, 1 executes a subroutine (FIG. 8) for control during engine operation, determines whether the engine is stopped, and sends a refueling command. If it is determined that the engine is not running, a subroutine (not shown) similar to that in FIG. 4 is executed for control when the engine is stopped, and if it is determined that the engine is stopped and the refueling command is sent, a subroutine for control when refueling (see FIG. 9) is executed. ) Is executed.

During engine operation, in the subroutine of FIG. 8, the electronic control unit 21 opens the first solenoid valve 41 (step S201a), and then, based on the output of the second pressure sensor 52, the internal pressure of the reservoir is equal to or higher than a predetermined pressure. It is determined whether or not (step S202a). If the internal pressure of the reservoir is less than the predetermined pressure, the third solenoid valve 43a is closed (step S203a), while if the internal pressure of the reservoir is equal to or higher than the predetermined pressure, the solenoid valve 43a is opened (step S204).
a). Therefore, while the engine is operating, the third electromagnetic valve 43a is controlled to be opened and closed so that the internal pressure of the reservoir is maintained below a predetermined pressure while maintaining the first electromagnetic valve 41 in the open state. This prevents the emission of the fuel evaporative emission during engine operation, and the fuel evaporative emission reservoir 22 at the time of the next refueling.
Make it possible to smoothly feed in.

When the engine is stopped, the first to third solenoid valves 4
1, 42 and 43a are maintained in the closed state, and the fuel tank 10 is hermetically closed, whereby the emission of the fuel evaporative emission is prevented. At the time of refueling, in the subroutine of FIG. 9, the electronic control unit 21 opens the second electromagnetic valve 42 and operates the compressor 23 (step S5).
01a), the fuel evaporative gas in the fuel tank 10 is sent into the reservoir 22 by the compressor 23, thereby gradually decreasing the internal pressure of the fuel tank. When it is determined in step S502a that the internal pressure of the fuel tank has become equal to or lower than the atmospheric pressure based on the output of the first pressure sensor 51, the electronic control unit 21 closes the second electromagnetic valve 42 and stops the operation of the compressor 23. Then, the filler lid 12 is opened via the filler lid opening / closing drive unit 11 (step S503a).

After that, refueling is performed as in the case of the first embodiment. Then, when the end of refueling is determined in step S504a based on the output of the refueling end detection switch 13,
The electronic control unit 21 opens the third solenoid valve 43a (step S505a). As a result, the fuel evaporative gas in the reservoir 22 flows into the fuel tank 10 through the third pipe 33a, so that the internal pressure of the reservoir gradually decreases while the internal pressure of the fuel tank gradually increases. During this time, the electronic control unit 2
1 repeatedly determines whether or not the difference between the fuel tank internal pressure and the reservoir internal pressure (tank-reservoir differential pressure) has become equal to or lower than a predetermined pressure based on the outputs of the first and second pressure sensors 51 and 52 (step). S506a).

If this differential pressure becomes less than the predetermined pressure and therefore the fuel tank internal pressure and the reservoir internal pressure are balanced, step S
When it is determined by 506a, the electromagnetic control unit 21 determines that the third
The solenoid valve 43a is closed. As a result, the inside of the fuel tank 10 is pre-pressurized to suppress the generation of fuel vaporized gas within the tank, and a margin is given to the internal pressure of the reservoir during refueling. Next, the control unit closes the filler lid 12 (step S508a) and ends the subroutine of FIG.

Hereinafter, a fuel transpiration prevention device according to a third embodiment of the present invention will be described with reference to FIG. Compared with the device of the second embodiment (FIG. 7), the device of the present embodiment has a third pipe 33b corresponding to the third pipe 33a of FIG.
First with respect to the solenoid valve 41 on the intake manifold 2 side
The difference is that they communicate with the pipe 31. The rest of the configuration is the same as that of the second embodiment, so description will be omitted.

The operation of the apparatus shown in FIG. 10 will be briefly described below. The electronic control unit 21 executes the same main routine (not shown) for fuel evaporation prevention control as shown in FIG. 2 at a predetermined cycle. Then, the control unit 21 has a first
And, as in the case of the second embodiment, when it is determined that the engine operation is not stopped, the control for the engine operation,
When the same subroutine (not shown) as the subroutine shown in FIG. 8 is executed and it is determined that the engine is stopped and the refueling command is not sent, a subroutine similar to that shown in FIG. ) Is executed, and when it is determined that the engine is stopped and the refueling command is sent, the subroutine of FIG. 11 (corresponding to FIG. 9) for refueling control is executed.

When the engine is operating, the electronic control unit 21
After opening the first solenoid valve 41, the third solenoid valve 43b is closed if the internal pressure of the reservoir is less than the predetermined pressure, while the solenoid valve 43a is opened if the internal pressure of the reservoir is equal to or higher than the predetermined pressure. The first solenoid valve 4 to prevent the evaporative emission
The third solenoid valve 43a is controlled to be opened / closed so that the internal pressure of the reservoir is maintained below a predetermined pressure while maintaining 1 in the open state.

When the engine is stopped, the first to third solenoid valves 4
1, 42 and 43b are maintained in the closed state, and the fuel tank 10 is hermetically closed, whereby the emission of the fuel evaporative gas is prevented. At the time of refueling, in the subroutine of FIG. 11, the electronic control unit 21 opens the second electromagnetic valve 42 and operates the compressor 23 (step S50).
1b), the fuel evaporative gas in the fuel tank 10 is sent into the reservoir 22 by the compressor 23, and when it is determined in step S502b that the internal pressure of the fuel tank has become equal to or lower than the atmospheric pressure, the electronic control unit 21 determines that the second solenoid valve 42 Is closed, the operation of the compressor 23 is stopped, and the filler lid 12 is opened via the filler lid opening / closing drive unit 11 (step S503b).

After that, refueling is performed as in the case of the first and second embodiments. Then, the refueling is finished in step S50.
When the determination is made in 4b, the electronic control unit 21 closes the filler lid 12 (step S505b) and ends the subroutine of FIG. Hereinafter, a fuel transpiration prevention device according to a fourth embodiment of the present invention will be described with reference to FIG.

Compared with the device of the first embodiment (FIG. 1),
The apparatus of this embodiment is an air cleaner 60 dedicated to fresh air intake.
The difference is that it is equipped with. This air cleaner 60
Is connected to the reservoir 22 via a third pipe 33c, and a third solenoid opening / closing valve 43c for allowing or blocking the introduction of fresh air into the reservoir 22 via the pipe 33c is provided in the middle of the pipe 33c. There is. Also, the fourth pipe 3
4c has one end with the compressor 23 and the canister 2
4 is connected to the first pipe 31 and the other end is
The second solenoid valve 42 is connected to the second pipe 32 on the fuel tank 10 side. In addition, in this embodiment, the display lamp 5
No. 4 and the lamp driving unit 55 are not provided.
Different from the embodiment. The rest of the configuration is the same as that of the first embodiment, so the explanation is omitted.

The operation of the apparatus shown in FIG. 12 will be briefly described below. The electronic control unit 21 executes the same main routine (not shown) for fuel evaporation prevention control as shown in FIG. 2 at a predetermined cycle. Then, the control unit 21 has a first
As in the case of the embodiment, when it is determined that the engine operation is not stopped, a subroutine (FIG. 13) for control during engine operation is executed, and it is determined that the engine is stopped and the refueling command is not sent. Subroutine (not shown) similar to FIG. 4 for controlling when the engine is stopped
Further, when it is determined that the engine is stopped and the refueling command is sent, a sub-routine (not shown) corresponding to the sub-routine in FIG. 5 for refueling control is executed.

During engine operation, in the subroutine of FIG. 13, the electronic control unit 21 opens the first solenoid valve 41 to prevent the emission of fuel vapor (step S201).
c) Next, it is determined whether the internal pressure of the reservoir is equal to or higher than a predetermined pressure (step S202c). If the internal pressure of the reservoir is less than the predetermined pressure, the third and fourth solenoid valves 43c, 4
While closing 4c (step S203c), if the internal pressure of the reservoir is equal to or higher than a predetermined pressure, both solenoid valves 43c and 44c are opened (step S204c). When the solenoid valves 43c and 44c are opened, the fuel evaporative gas in the reservoir 22 is discharged from the second pipe 32.
Through the caster 24, the fourth pipe 34c, and the first pipe 31, which are located on the downstream side, the negative pressure of the intake air causes the air to flow into the intake manifold 2, and the internal pressure of the reservoir gradually decreases. Then, when the internal pressure of the reservoir decreases, fresh air flows into the canister 24 from the air cleaner 60 via the reservoir 22, and the new air purges the canister 24. That is, the fuel evaporative gas adsorbed by the canister 24 is separated from the canister 24 and burns in the engine 1.

When the engine is stopped, the first to fourth solenoid valves 4
1, 42, 43c and 44c are maintained in the closed state and the fuel tank 10 is hermetically closed. At the time of refueling, the electronic control unit 21 opens the second electromagnetic valve 42 and operates the compressor 23 in a subroutine substantially similar to the subroutine of FIG. As a result, the fuel evaporative gas in the fuel tank 10 is sent into the reservoir 22 via the first and second pipes 31, 32, the compressor 23 and the canister 24, and the fuel tank internal pressure gradually decreases. Then, when it is determined that the internal pressure of the fuel tank has become equal to or lower than the atmospheric pressure, the electronic control unit 21 closes the second electromagnetic valve 42 and stops the operation of the compressor 23, and then, via the filler lid opening / closing drive unit 11. Filler lid 12
To open.

As described above, when the internal pressure of the fuel tank becomes equal to or lower than the atmospheric pressure, the filler lid 12 opens, so that the refueling worker should insert the filler cap 10c into the filler duct 10a.
Then, the fuel filler is opened and the fuel filler is opened to start refueling the fuel tank 10. At this time, since the internal pressure of the fuel tank is equal to or lower than the atmospheric pressure, the fuel evaporative gas does not blow out from the fuel tank 10 even if the fuel supply port is opened.

After that, when the refueling end signal is input, the electronic control unit 21 closes the filler lid 12 via the filler lid opening / closing drive unit 11. The present invention
The present invention is not limited to the modification examples according to the first to fourth embodiments and the first embodiment described above, but various modifications are possible. For example, in each of the above-described embodiments, the case where the fuel evaporation preventing device is attached to the fuel injection type engine has been described, but the device of the present invention is also applicable to the engine with a carburetor.

Further, in the second to fourth embodiments, the automatic opening / closing type filler lid is used, but as described in the modification of the first embodiment, this kind of filler lid is used in the present invention. It is not essential to control the opening and closing of the filler lid. In the first to fourth embodiments, the fuel tank 10 is closed when the engine is stopped to prevent the emission of the fuel evaporative emission except when refueling. However, this is an essential item in the present invention. Absent.

The display lamp 54 described in the first embodiment is attached to the devices of the second to fourth embodiments so that the refueling possible display is performed when the pressure inside the fuel tank 10 is reduced to a pressure lower than a set value. You can It is not essential to use the display lamp 54 as the display means. Furthermore, in the first to fourth embodiments, when the filler lid is opened after the internal pressure of the fuel tank is reduced to a set pressure, for example, the atmospheric pressure or less,
Although the fuel supply is immediately performed, it may be determined again whether the internal pressure of the fuel tank is equal to or lower than the set pressure after the filler lid is opened. In this case, if the determination result is affirmative, the start of refueling work is permitted, while if the determination result is negative, the second solenoid valve is opened and the compressor is operated to depressurize the fuel tank again. .

Further, the refueling switch 53 as the refueling command means, the refueling end detection switch 13 and the like can be variously modified.

[0056]

As described above, the fuel transpiration prevention apparatus according to one aspect of the present invention includes a reservoir that communicates with the fuel tank through the reserve passage and a gas in the fuel tank that is interposed in the reserve passage. A compressor leading to the reservoir side, a pressure sensor for detecting the internal pressure of the fuel tank, a compressor operating means for operating the compressor when the refueling command means is activated, and a pressure within the set value within the fuel tank when the refueling command means is activated. Since it is provided with a display unit that performs a display operation in response to the fact that the pressure sensor detects that the fuel tank has been depressurized, the fuel tank can be depressurized and the depressurization completed can be displayed by operating the refueling command unit prior to refueling. By checking the decompression completion display and then refueling, unnecessary fuel from the refueling port of the fuel tank during refueling The release of the evaporation gas can be reliably prevented.

In addition, a fuel evaporation prevention apparatus according to another aspect of the present invention includes a reservoir which is communicated with a fuel tank through a reserve passage, and a compressor which is interposed in the reserve passage and guides gas in the fuel tank to the reservoir side. A pressure sensor for detecting the internal pressure of the fuel tank, a filler lid opening / closing means for opening / closing the filler lid of the fuel tank, a compressor operating means for operating the compressor when the refueling command means operates, and a refueling command means for operating. Since the pressure sensor detects that the pressure in the fuel tank has become less than or equal to the set value, the filler lid opening / closing means is provided with a lid opening / closing control means for outputting a command signal for opening the filler lid, so that the fuel lid can be operated at the time of refueling. It is possible to prevent the emission of fuel evaporative emission from the fuel tank.

[Brief description of drawings]

FIG. 1 is a schematic view showing a fuel evaporation prevention device according to a first embodiment of the present invention together with peripheral elements.

FIG. 2 is a flowchart showing a main routine of a fuel transpiration prevention control program executed by the electronic control unit shown in FIG.

FIG. 3 is a flowchart showing in detail a subroutine for control during engine operation shown in FIG.

FIG. 4 is a flowchart showing in detail a subroutine for control when the engine shown in FIG. 2 is stopped.

5 is a flowchart showing in detail a subroutine for control during refueling shown in FIG. 2. FIG.

FIG. 6 is a flowchart showing a subroutine for control during refueling in a modification of the first embodiment.

FIG. 7 is a schematic view of a fuel evaporation prevention device according to a second embodiment of the present invention.

FIG. 8 is a flowchart of a subroutine for control during engine operation in the second embodiment.

FIG. 9 is a flowchart of a subroutine for control during refueling in the second embodiment.

FIG. 10 is a schematic view of a fuel evaporation prevention device according to a third embodiment of the present invention.

FIG. 11 is a flowchart of a subroutine for control during refueling in the third embodiment.

FIG. 12 is a schematic view of a fuel evaporation prevention device according to a fourth embodiment of the present invention.

FIG. 13 is a flowchart of a subroutine for control during engine operation in the fourth embodiment.

[Explanation of symbols]

1 Engine 2 Intake Manifold 4,60 Air Cleaner 10 Fuel Tank 10c Filler Cap 11 Filler Lid Opening / Closing Drive 12 Filler Lid 13 Refueling End Detection Switch 21 Electronic Control Unit 22 Reservoir 23 Compressor 24 Canister 31, 32, 33, 34 Pipe 41, 42 , 43, 43a, 43b, 43c, 44, 4
4c Electromagnetic on-off valve 51, 52 Pressure sensor 53 Oil supply switch 54 Indicator lamp 55 Lamp drive unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area F02M 33/00 A 37/04 A

Claims (2)

[Claims] 1. A reservoir that is in communication with a fuel tank through a reserve passage, a compressor that is interposed in the reserve passage and introduces gas in the fuel tank to the reservoir side, and a pressure sensor that detects the internal pressure of the fuel tank. Compressor operating means for operating the compressor when the refueling command means operates, and the fact that the pressure sensor detects that the refueling command means operates and that the pressure in the fuel tank is equal to or lower than a set value. A fuel transpiration prevention device, comprising: a display unit that performs a display operation. 2. A reservoir which communicates with the fuel tank through a reserve passage, a compressor which is interposed in the reserve passage and guides gas in the fuel tank to the reservoir side, and a pressure sensor which detects the internal pressure of the fuel tank. A filler lid opening / closing means for opening / closing the filler lid of the fuel tank, a compressor operating means for operating the compressor when the refueling command means operates, and a pressure lower than a set value in the fuel tank when the refueling command means operates. The fuel transpiration prevention device further comprises: a lid opening / closing control unit that outputs a command signal for opening the filler lid to the filler lid opening / closing unit when the pressure sensor detects that