JP2013057261A - Fuel vapor treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel vapor treatment apparatus comprising a closing valve having small electromotive force of an electric drive part during valve-opening, a fewer number of components, and a simple structure.SOLUTION: In this fuel vapor treatment apparatus 10, a closing valve 40 performs opening and closing driving of a valve member 46 by a solenoid 49. A pump 60 can pressurize or depressurize a space at an atmosphere-side of the valve member 46. A control device 75 controls the pump 60 so that an atmosphere-side pressure and a tank-side pressure are equivalent before the valve-opening of the closing valve 40. Accordingly, the axial force acting on the valve member 46 is balanced by changing the atmosphere-side pressure by the pump 60, and the electromotive force of the solenoid 49 during the valve-opening of this closing valve 40 becomes small. There is no need for forming a passage in a housing 41 for balancing the axial force acting on the valve member 46 or for adding a member such as a hose or the like. Thus, the number of components of the closing valve 40 is reduced to simplify the structure.

Description

  The present invention relates to a fuel vapor processing apparatus.

2. Description of the Related Art There is known a fuel vapor processing apparatus that supplies and processes fuel vapor generated in a vehicle fuel tank to an intake passage of an engine. This fuel vapor processing apparatus includes a block valve provided in an air communication path communicating with the atmosphere inside a fuel tank. The blocking valve is opened when fuel is supplied to the fuel tank or when the fuel vapor in the fuel tank is purged, so that the pressure in the fuel tank is equal to the atmospheric pressure.
In the sealing valve disclosed in Patent Document 1, the outer diameter of the pressure receiving surface on the atmosphere side of the valve member is equal to the outer diameter of the bellows provided on the valve member opposite to the atmosphere side. Further, the atmosphere side space of the valve member and the inside of the bellows communicate with each other via a hose or the like.

JP 2006-258135 A

However, the blocking valve disclosed in Patent Document 1 requires that a passage be formed in the housing and a member such as a hose be attached in order to communicate the space on the atmosphere side of the valve member with the inside of the bellows. Therefore, there is a problem that the number of parts of the blocking valve is large and the structure is complicated.
The present invention has been made in view of the above points, and an object of the present invention is to provide a sealing valve that has a small electromotive force at the time of valve opening, a small number of parts, and a simple structure. A fuel vapor treatment apparatus is provided.

The invention according to claim 1 is a fuel vapor processing apparatus for supplying and processing fuel vapor generated in a fuel tank for a vehicle to an intake passage of an engine, wherein the atmosphere communication passage, a purge passage, a block valve, a tank side pressure sensor And an atmospheric pressure sensor, pressure increasing / decreasing means and a control device. The atmosphere communication path can communicate the vehicle fuel tank to the atmosphere. The purge passage can communicate the air communication passage with the intake passage of the engine.
The blocking valve includes a valve member that can open and close the atmosphere communication path, and an electric drive unit that drives the valve member to open and close. The tank side pressure sensor detects a tank side pressure acting on the first pressure receiving surface of the valve member on the fuel tank side. The atmospheric pressure sensor detects the atmospheric pressure acting on the second pressure receiving surface on the atmospheric side of the valve member.

The pressure increasing / decreasing means is provided on the atmosphere side with respect to the valve member. The pressure increasing / decreasing means can pressurize and depressurize the space on the atmosphere side with respect to the valve member in the atmosphere communication path when the blocking valve is closed. The control device controls the pressure increasing / decreasing means so that the atmospheric pressure and the tank pressure are equal prior to the opening of the block valve.
According to such a fuel vapor processing apparatus, it is possible to balance the axial force acting on the valve member by changing the atmospheric pressure by the pressure increasing / decreasing means. Thereby, the electromotive force of the electric drive part at the time of valve opening of a blocking valve can be made small.
Further, it is not necessary to form a passage in the housing and to attach a member such as a hose in order to balance the axial force acting on the valve member. Therefore, the number of parts of the block valve can be reduced and the structure can be simplified.

In the invention according to claim 2, the control device operates the pressure increasing / decreasing means so that the atmospheric pressure is increased when the atmospheric pressure is smaller than the tank pressure, and the atmospheric device is operated when the atmospheric pressure is larger than the tank pressure. The pressure increasing / decreasing means is operated so that the pressure decreases.
Thereby, the axial force acting on the valve member can be balanced.

In a third aspect of the invention, the control device calculates a pressure difference between the tank side pressure and the atmosphere side pressure when a valve opening command for the blocking valve is given. The control device operates the pressure increasing / decreasing means when the calculated absolute value of the pressure difference is larger than a predetermined threshold value, and opens the block valve when the calculated absolute value of the pressure difference is equal to or less than the threshold value.
Thus, when the axial force acting on the valve member is balanced and it is not necessary to operate the pressure-increasing / decreasing means, it is possible to immediately perform refueling or purging of fuel vapor by opening the block valve immediately.

According to a fourth aspect of the present invention, when the predetermined value has elapsed from the start of operation of the pressure increasing / decreasing means, the control device is configured such that when the absolute value of the pressure difference is greater than the threshold value, the valve member and the pressure increasing / decreasing means in the atmospheric communication path. It is determined that there is an air leak between
Thereby, air leakage between the valve member and the pressure increasing / decreasing means can be detected.

A fuel vapor processing apparatus according to a fifth aspect of the present invention includes a first branch passage, a passage switching valve, and a second branch passage. The first branch passage is connected to the atmosphere side with respect to the pressure increasing / decreasing means in the atmosphere communication passage.
The passage switching valve is provided in a section between the blocking valve and the pressure increasing / decreasing means in the atmospheric communication passage. The passage switching valve includes a first port connected to the block valve side of the section, a second port connected to the pressure increasing / decreasing means side of the section, and a three-way valve having a third port connected to the first branch passage. Become. The passage switching valve has a first operating position that blocks the first port and the third port while communicating the first port and the second port, and a first port that blocks the first port and the second port. And the third port is operated to the second operating position.

One end of the second branch passage is connected between the blocking valve and the passage switching valve in the atmospheric communication passage, and the other end is connected between the passage switching valve and the pressure increasing / decreasing means in the atmospheric communication passage. The second branch passage has a throttle portion.
The control device determines that air leakage has occurred on the fuel tank side with respect to the blocking valve in the following two cases. In the first case, when the blocking valve is opened, a value at which the atmospheric pressure converges when the pressure-reducing means is depressurized while operating the passage switching valve to the second operating position is set as the first reference value. This is a case where the atmospheric pressure does not become smaller than the first reference value when the pressure increasing / decreasing means is operated while the switching valve is operated to the first operating position.

In the second case, when the closing valve is opened, the value at which the atmospheric pressure converges when the pressure increasing / decreasing means is pressurized while operating the passage switching valve to the second operating position is set as the second reference value. This is a case where the atmospheric pressure does not become larger than the second reference value when the pressure increasing / decreasing means is pressurized while operating the passage switching valve to the first operating position.
Thereby, it is possible to detect an air leak on the fuel tank side with respect to the blocking valve.
According to a sixth aspect of the present invention, there is provided a fuel vapor processing apparatus comprising a canister that is provided between a fuel tank and a pressure-increasing / decreasing means and adsorbs fuel vapor generated in the fuel tank.
Thus, the fuel vapor can be adsorbed to the canister at one end, taken out when necessary, and supplied to the intake passage.

1 is a view showing a fuel vapor processing apparatus according to a first embodiment of the present invention. It is a flowchart which shows the processing flow regarding the control action of the control apparatus of FIG. It is a time chart which shows the change of the atmospheric side pressure when the control apparatus of FIG. It is a time chart which shows the change of the atmospheric side pressure when the control apparatus of FIG. It is a figure which shows the fuel vapor processing apparatus by 2nd Embodiment of this invention. It is a flowchart which shows the processing flow regarding the detection of air leaks, such as a fuel tank, among the control action of the control apparatus of FIG. It is a time chart which shows the change of the atmospheric side pressure when the control apparatus of FIG. It is a time chart which shows the change of the atmospheric pressure when the control apparatus of the fuel vapor processing apparatus by the modification of 2nd Embodiment of this invention pressurizes a pump.

Hereinafter, a fuel vapor processing apparatus according to a plurality of embodiments of the present invention will be described with reference to the drawings. In the embodiments, substantially the same components are denoted by the same reference numerals and description thereof is omitted.
(First embodiment)
A fuel vapor processing apparatus according to a first embodiment of the present invention is shown in FIG. The engine 1 shown in FIG. 1 converts the force that the combustion gas expanding in the cylinder 2 pushes the piston 3 into a rotational force and outputs it when the air-fuel mixture of fuel and air is combusted in the cylinder 2. The vehicle travels by rotationally driving the drive wheels with the output torque of the engine 1.

A vehicle fuel tank (hereinafter referred to as a fuel tank) 4 is a tank for storing fuel of the engine 1. The fuel of the engine 1 is, for example, gasoline or light oil. In the fuel tank 4, fuel vapor is generated by the vaporization of gasoline.
The fuel vapor processing apparatus 10 supplies the fuel vapor generated in the fuel tank 4 to the intake passage 6 of the intake pipe 5 of the engine 1 for processing. The fuel vapor processing apparatus 10 includes a first pipe 20, a second pipe 22, a third pipe 24, a fourth pipe 26, a purge pipe 29, a canister 31, a purge valve 34, a block valve 40, and a pump 60 as “pressure increasing / decreasing means”. , A tank internal pressure sensor 65 as an “tank side pressure sensor”, an atmospheric pressure sensor 70, a control device 75, and the like.

The first pipe 20 has one end connected to the fuel tank 4 and the other end connected to the canister 31. The first pipe 20 has a first passage 21 that allows the fuel tank 4 and the canister 31 to communicate with each other.
The second pipe 22 has one end connected to the canister 31 and the other end connected to the housing 41 of the blocking valve 40. The second pipe 22 has a second passage 23 that allows the inside of the canister 31 and the inside of the housing 41 to communicate with each other.
The third pipe 24 has one end connected to the housing 41 and the other end connected to the first connection port 61 of the pump 60. The third pipe 24 has a third passage 25 that allows the inside of the housing 41 to communicate with the first connection port 61 of the pump 60.

The fourth pipe 26 has one end connected to the second connection port 62 of the pump 60 and the other end opened to the atmosphere. The fourth pipe 26 has a fourth passage 27 that allows the second connection port 62 of the pump 60 to communicate with the atmosphere. A filter 28 is provided in the middle of the fourth passage 27.
The first passage 21, the second passage 23, the third passage 25, and the fourth passage 27 constitute an “atmospheric communication passage” in the claims. These passages 21, 23, 25, and 27 can communicate with the atmosphere inside the fuel tank 4.
The purge pipe 29 has one end connected to the canister 31 and the other end connected to the intake pipe 5 of the engine 1. The purge pipe 29 has a purge passage 30 that allows the inside of the canister 31 and the inside of the intake pipe 5 to communicate with each other. The purge passage 30 guides the fuel vapor desorbed from the canister 31 into the intake pipe 5 of the engine 1.

The canister 31 includes a container 31 and an adsorbent 33 in the container 31. The adsorbent 33 is activated carbon, for example, and can adsorb fuel vapor generated in the fuel tank 4.
The purge valve 34 is provided in the middle of the purge passage 30 and is composed of, for example, an electromagnetic valve. The purge valve 34 can adjust the amount of fuel vapor flowing from the canister 31 through the purge passage 30 into the intake pipe 5 by changing the opening degree of the purge passage 30. The purge valve 34 is electrically connected to the control device 75 and operates based on an electrical signal output from the control device 75.

  The blocking valve 40 includes a housing 41, a valve member 46, a solenoid 49 as an “electric drive unit”, and a spring 53. The housing 41 includes a first chamber 42 that houses a solenoid 49 and the like, a second chamber 43 that communicates with the second passage 23, and a third chamber 44 that communicates with the third passage 25. The third chamber 44 has an opening 45 that opens to the inner wall that defines the second chamber 43. The valve member 46 can open and close the opening 45 of the third chamber 44.

The solenoid 49 magnetizes the fixed core 51 by energizing the coil 50 and attracts the movable core 52 to the fixed core 51. Accordingly, the movable core 52 moves to the side opposite to the third chamber 44 against the urging force of the spring 53. At this time, the valve member 46 moves together with the movable core 52 so as to be separated from the opening 45 and allows the second chamber 43 and the third chamber 44 to communicate with each other.
The magnetic force of the fixed core 51 is lost when the power supply to the coil 50 is stopped. The movable core 52 moves to the third chamber 44 side by the urging force of the spring 53 when the magnetic attractive force of the fixed core 51 disappears. As a result, the valve member 46 moves together with the movable core 52 to close the opening 45 and shut off the second chamber 43 and the third chamber 44.

  The pump 60 can pressurize and depressurize the space on the atmosphere side with respect to the valve member 46 when the blocking valve 40 is closed. That is, when the valve member 46 closes the opening 45, the pump 60 pumps air taken from the atmosphere through the fourth passage 27 to the third passage 25 and the third chamber 44, thereby The pressure acting on the second pressure receiving surface 48 on the side, that is, the atmospheric pressure can be increased. Further, the pump 60 can reduce the atmospheric pressure by sucking out air from the third passage 25 and the third chamber 44 when the valve member 46 closes the opening 45.

The tank internal pressure sensor 65 detects the pressure acting on the first pressure receiving surface 47 of the valve member 46 on the fuel tank 4 side, that is, the tank side pressure. The tank internal pressure sensor 65 outputs the detected tank side pressure to the control device 75 as an electrical signal.
The atmospheric pressure sensor 70 detects the atmospheric pressure acting on the second pressure receiving surface 48 of the valve member 46. The atmospheric pressure sensor 70 outputs the detected atmospheric pressure as an electrical signal to the control device 75.

  The control device 75 includes a microcomputer having a CPU, a ROM, a RAM, and the like (not shown). A tank internal pressure sensor 65 and an atmospheric pressure sensor 70 are electrically connected to the control device 75. The control device 75 controls each part of the fuel vapor processing device 10 according to a predetermined control program recorded in the ROM based on the electrical signal transmitted from each sensor.

  When the closing valve 40 is closed, the control device 75 operates the pump 60 so that the atmospheric pressure and the tank pressure become equal prior to the opening of the closing valve 40. Specifically, when a valve opening command for the blocking valve 40 is issued, the control device 75 first calculates the pressure difference between the tank side pressure and the atmosphere side pressure. Next, the control device 75 operates the pump 60 when the calculated absolute value of the pressure difference is larger than a predetermined threshold value. At this time, the control device 75 operates the pump 60 so that the atmospheric pressure increases when the atmospheric pressure is smaller than the tank pressure, and the atmospheric pressure decreases when the atmospheric pressure is larger than the tank pressure. The pump 60 is activated.

Further, the control device 75 opens the block valve 40 when the absolute value of the pressure difference between the calculated atmospheric pressure and the tank pressure is equal to or less than the threshold value.
In addition, when a predetermined time has elapsed from the start of operation of the pump 60, the control device 75 determines that the absolute value of the pressure difference between the atmospheric pressure and the tank pressure is greater than the threshold value, between the valve member 46 and the pump 60. It is determined that there is a possibility of air leakage, and for example, a warning lamp is turned on.

  Next, the operation of the control device 75 will be described with reference to FIG. FIG. 2 shows a processing flow relating to the control operation of the control device 75. A series of processing shown in FIG. 2 is started immediately after the engine 1 is started, for example, and is repeatedly executed every predetermined time.

  When the processing flow of FIG. 2 is started, first, in step S101 (hereinafter, “step” is omitted and simply indicated by the symbol “S”), the control device 75 issues a valve opening command for the blocking valve 40. It is determined whether or not. The opening command for the blocking valve 40 is issued when the fuel tank 4 is supplied with fuel or when the fuel vapor in the fuel tank 4 is purged. If the determination in S101 is affirmative (S101: YES), the process proceeds to S102. On the other hand, if the determination in S101 is negative (S101: NO), the series of routines shown in FIG. 2 is exited.

In S102, the control device 75 detects the tank side pressure Pt. After S102, the process proceeds to S103.
In S103, the control device 75 determines whether or not the absolute value (| Pt−Pa |) of the pressure difference between the tank side pressure Pt and the atmosphere side pressure Pa is equal to or less than a predetermined threshold value P1. If the determination in S103 is affirmative (S103: YES), the process proceeds to S104. On the other hand, when the determination in S103 is negative (S103: NO), the process proceeds to S105.

In S104, the control device 75 operates the solenoid 49 so that the blocking valve 40 is opened, and exits a series of routines shown in FIG.
In S105, when the atmospheric pressure Pa is smaller than the tank pressure Pt (Pa <Pt), the control device 75 operates the pump 60 so that the atmospheric pressure Pa increases. In addition, when the atmospheric pressure Pa is greater than the tank pressure Pt (Pa> Pt), the control device 75 operates the pump 60 so that the atmospheric pressure Pa decreases. After S105, the process proceeds to S106.

In S106, the control device 75 determines whether or not the absolute value (| Pt−Pa |) of the pressure difference between the tank side pressure Pt and the atmospheric side pressure Pa is equal to or less than a predetermined threshold value P1. If the determination in S106 is affirmative (S106: YES), the process proceeds to S107. On the other hand, when the determination in S106 is negative (S106: NO), the process proceeds to S108.
In S107, the control device 75 operates the solenoid 49 so that the blocking valve 40 is opened, and exits the series of routines shown in FIG.

In S108, the control device 75 determines whether or not the time T that has elapsed since the start of the operation of the pump 60 in S105 is equal to or longer than the predetermined time T1. If the determination in S108 is affirmative (S108: YES), the process proceeds to S109. On the other hand, when the determination in S108 is negative (S108: NO), the process returns to S106.
In S109, the control device 75 determines that there is a possibility of air leakage between the valve member 46 and the pump 60, turns on the warning lamp, and exits the series of routines shown in FIG.

FIG. 3 shows a change in the atmospheric pressure Pa [kPa] when the pump 60 is operated so that the atmospheric pressure Pa is determined to be smaller than the tank pressure Pt in S105 of FIG. It is a time chart which shows. The time t0 in FIG. 3 is the operation start time of the pump 60. Time t1 is a point in time when a predetermined time T1 has elapsed from time t0.
When there is no air leakage, as shown by a solid line Pa, the difference from the tank side pressure Pt is within the threshold value P1 by time t1. However, when there is an air leak, the difference from the tank side pressure Pt becomes larger than the threshold value P1 at time t1, as indicated by a two-dot chain line Pa ′. The control device 75 detects an air leak between the valve member 46 and the pump 60 based on the difference between the above two cases.

FIG. 4 shows a change in the atmospheric pressure Pa [kPa] when the pump 60 is operated so that the atmospheric pressure Pa is determined to be larger than the tank pressure Pt in S105 of FIG. It is a time chart which shows. The time t10 in FIG. 4 is the operation start time of the pump 60. Time t11 is a point in time when a predetermined time T1 has elapsed from time t10.
When there is no air leakage, as shown by a solid line Pa, the difference from the tank side pressure Pt is within the threshold value P1 by time t11. However, when there is an air leak, the difference from the tank side pressure Pt becomes larger than the threshold value P1 at time t11 as indicated by a two-dot chain line Pa ′. The control device 75 detects an air leak between the valve member 46 and the pump 60 based on the difference between the above two cases.

As described above, in the fuel vapor processing apparatus 10 according to the first embodiment, the blocking valve 40 opens and closes the valve member 46 that can communicate and block the second passage 23 and the third passage 25, and the valve member 46. It consists of a solenoid 49 for driving.
The pump 60 can pressurize and depressurize the space on the atmosphere side with respect to the valve member 46 when the blocking valve 40 is closed. That is, when the valve member 46 closes the opening 45, the pump 60 pumps air taken from the atmosphere through the fourth passage 27 to the third passage 25 and the third chamber 44, thereby The pressure acting on the second pressure receiving surface 48 on the side, that is, the atmospheric pressure can be increased. Further, the pump 60 can reduce the atmospheric pressure by sucking out air from the third passage 25 and the third chamber 44 when the valve member 46 closes the opening 45.

When the closing valve 40 is closed, the control device 75 controls the pump 60 so that the atmospheric pressure and the tank pressure are equal before the closing valve 40 is opened.
According to such a fuel vapor processing apparatus 10, the axial force acting on the valve member 46 can be balanced by the pump changing the atmospheric pressure. Thereby, the electromotive force of the solenoid 49 when the blocking valve 40 is opened can be reduced.
Further, it is not necessary to form a passage in the housing 41 and to attach a member such as a hose to balance the axial force acting on the valve member 46. Therefore, the number of parts of the blocking valve 40 can be reduced and the structure can be simplified.

In the first embodiment, the control device 75 operates the pump 60 so that the atmospheric pressure increases when the atmospheric pressure is smaller than the tank pressure, and the atmospheric pressure when the atmospheric pressure is larger than the tank pressure. The pump 60 is actuated so that is reduced.
Thereby, the axial force acting on the valve member 46 can be balanced.

Moreover, in 1st Embodiment, the control apparatus 75 will calculate the pressure difference of a tank side pressure and an atmospheric | air pressure side pressure, when the valve opening command of the sealing valve 40 is made. The control device 75 operates the pump 60 when the calculated absolute value of the pressure difference is larger than a predetermined threshold value, and opens the closing valve 40 when the calculated absolute value of the pressure difference is equal to or less than the threshold value.
As a result, when the axial force acting on the valve member 46 does not need to operate the balance pump 60, the closing valve 40 is quickly opened, so that fuel supply or fuel vapor purging can be performed immediately.

In the first embodiment, when the predetermined time has elapsed from the start of operation of the pump 60, the control device 75 determines that the absolute value of the pressure difference between the tank side pressure and the atmosphere side pressure is greater than the threshold value, It is determined that there is an air leak with the pump 60. Thereby, an air leak between the valve member 46 and the pump 60 can be detected.
In the first embodiment, a canister 31 is provided between the fuel tank 4 and the pump 60. Thereby, the fuel vapor can be adsorbed to the canister 31 at one end, taken out when necessary, and supplied to the intake passage 6.

(Second Embodiment)
A fuel vapor processing apparatus according to a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 5, in addition to the configuration of the fuel vapor processing apparatus 10 according to the first embodiment, the fuel vapor processing apparatus 80 according to the second embodiment includes a first branch pipe 81, a passage switching valve 83, and a second branch. A tube 87.
The first branch pipe 81 has a first branch passage 82 connected to the fourth pipe 26 and communicating with the fourth passage 27.

  The passage switching valve 83 is provided in the middle of the third pipe 24. The passage switching valve 83 is connected to the first port 84 connected to the blocking valve 40 side of the third pipe 24, the second port 85 connected to the pump 60 side of the third pipe 24, and the first branch passage 82 connected to the first branch passage 82. A three-way solenoid valve having three ports 86. The passage switching valve 83 has a first operating position that blocks the first port 84 and the third port 86 while communicating the first port 84 and the second port 85, and the first port 84 and the second port 85. The first port 84 and the third port 86 are operated to the second operating position while blocking. The operation position of the passage switching valve 83 is controlled by the control device 90.

  The second branch pipe 87 has one end connected between the blocking valve 40 and the passage switching valve 83 in the third pipe 24 and the other end between the passage switching valve 83 and the pump 60 in the third pipe 24. Connect. The second branch pipe 87 has a second branch passage 89 that forms a throttle portion 88 in the middle.

The control device 90 has a function of detecting air leakage in the fuel tank 4, the first passage 21, the canister 31, and the second passage 23 in addition to the function of the control device 75 according to the first embodiment.
Specifically, the control device 90 first sets a value at which the atmospheric pressure converges when the pump 60 is depressurized while the passage switching valve 83 is operated to the second operating position when the blocking valve 40 is opened. Store as a reference value. Next, when the atmospheric pressure does not become smaller than the first reference value when the predetermined time T2 has elapsed after the pump 60 is depressurized while operating the passage switching valve 83 to the first operating position, It is determined that there is a possibility that air leakage has occurred in the tank 4, the first passage 21, the canister 31, the second passage 23, the blocking valve 40 or the third passage 25, and for example, a warning lamp is turned on.

Next, the operation of the control device 90 will be described with reference to FIG. FIG. 6 shows a processing flow relating to detection of air leakage in the fuel tank 4 and the like in the control operation of the control device 90. A series of processes shown in FIG. 6 is started immediately after the closing valve 40 is opened, for example.
When the processing flow of FIG. 6 is started, first, in S201, the control device 90 operates the passage switching valve 83 to the first operating position. After S201, the process proceeds to S202.

In S202, the control device 90 operates the pump 60 to reduce the pressure. After S202, the process proceeds to S203.
In S203, the control device 90 determines whether or not the atmospheric pressure Pa has converged. If the determination in S203 is affirmative (S203: YES), the process proceeds to S204. On the other hand, if the determination in S203 is negative (S203: NO), S203 is repeatedly executed until the determination in S203 is positive.

In S204, the control device 90 stores the convergence value of the atmospheric pressure Pa as the first reference value Ps1, and stops the operation of the pump 60. After S204, the process proceeds to S205.
In S205, the control device 90 operates the passage switching valve 83 to the second operating position. After S205, the process proceeds to S206.
In S206, the control device 90 operates the pump 60 under reduced pressure. After S206, the process proceeds to S207.

  In S207, the control device 90 determines whether or not the time T that has elapsed since the start of the operation of the pump 60 in S206 is equal to or longer than the predetermined time T2. If the determination in S207 is affirmative (S207: YES), the process proceeds to S208. On the other hand, when the determination in S207 is negative (S207: NO), S207 is repeatedly executed until the determination in S207 is positive.

In S208, the control device 90 determines whether or not the atmospheric pressure Pa is greater than the first reference value Ps1. If the determination in S208 is affirmative (S208: YES), the process proceeds to S209. On the other hand, if the determination in S208 is negative (S208: NO), the process proceeds to S210.
In S209, the control device 90 determines that there is a possibility that air leakage has occurred in the fuel tank 4, the first passage 21, the canister 31, the second passage 23, the blocking valve 40 or the third passage 25, and a warning lamp Is turned on, and a series of routines shown in FIG. 6 is exited.
In S210, the control device 90 determines that there is no air leakage in the fuel tank 4, the first passage 21, the canister 31, the second passage 23, the blocking valve 40, or the third passage 25, and executes a series of routines shown in FIG. Exit.

FIG. 7 is a time chart showing changes in the atmospheric pressure Pa corresponding to the processing flow of FIG. The time t20 in FIG. 7 is the time when the pump 60 starts the pressure reducing operation in S202 of FIG. After time t20, the atmospheric pressure Pa decreases and converges to a constant value.
Time t21 in FIG. 7 is a time point when it is determined that the atmospheric pressure Pa has converged in S203 in FIG. 6 and the operation of the pump 60 is stopped in S204. At this time, the convergence value of the atmospheric pressure Pa is stored as the first reference value Ps1.

After time t21 in FIG. 7, the passage switching valve 83 is switched to the second operating position, and the pump 60 starts the pressure reducing operation. Along with this, the atmospheric pressure Pa decreases.
When there is no air leakage, as shown by the solid line Pa, the atmospheric pressure Pa becomes smaller than the first reference value Ps1 by time t22. However, when there is an air leak, the atmospheric pressure Pa does not become smaller than the first reference value Ps1 by time t22 as indicated by a two-dot chain line Pa ′. The control device 90 detects air leaks in the fuel tank 4, the first passage 21, the canister 31, the second passage 23, the blocking valve 40, and the third passage 25 based on the difference between the above two cases.

As described above, the fuel vapor processing apparatus 80 according to the second embodiment includes the first branch passage 82, the passage switching valve 83, and the second branch passage 89 having the throttle portion 88. The control device 75 sets, as the first reference value, a value at which the atmospheric pressure converges when the pump 60 is depressurized while operating the passage switching valve 83 to the second operating position when the blocking valve 40 is opened. In addition, when the air pressure is not lower than the first reference value when the pump 60 is depressurized while operating the passage switching valve 83 to the first operating position, the control device 75 performs the fuel tank 4, the first passage 21, It is determined that air leakage has occurred in the canister 31, the second passage 23, the blocking valve 40, or the third passage 25.
Thereby, it is possible to detect an air leak in the fuel tank 4, the first passage 21, the canister 31, the second passage 23, the blocking valve 40, or the third passage 25.

(Modification of the second embodiment)
In the modification of the second embodiment, the control device sets the second value at which the atmospheric pressure converges when the pump is pressurized while operating the passage switching valve to the second operating position when the blocking valve is opened. Store as a reference value. Further, the control device is configured to provide a fuel tank, a first fuel tank, a first fuel tank, a first fuel tank, a first fuel tank, a first fuel tank, a first fuel tank, a first fuel tank, a first fuel tank, a first fuel tank; It is determined that there may be an air leak in the passage, canister, second passage, blockade valve, or third passage.

FIG. 8 is a time chart showing changes in the atmospheric pressure Pa due to the control operation of the control device. Time t30 in FIG. 8 is a point in time when the pump starts the first pressurizing operation. After time t30, the atmospheric pressure Pa increases and converges to a constant value.
Time t31 in FIG. 8 is a point in time when it is determined that the atmospheric pressure Pa has converged and the operation of the pump is stopped. At this time, the convergence value of the atmospheric pressure Pa is stored as the second reference value Ps2.

After time t31 in FIG. 8, the passage switching valve is switched to the second operating position, and the pump starts the second pressurizing operation. Along with this, the atmospheric pressure Pa increases.
When there is no air leakage, the atmospheric pressure Pa becomes greater than the second reference value Ps2 by time t32 as indicated by the solid line Pa. However, when there is an air leak, the atmospheric pressure Pa does not become larger than the second reference value Ps2 by time t32 as indicated by a two-dot chain line Pa ′. The control device detects air leaks in the fuel tank, the first passage, the canister, the second passage, the blocking valve, and the third passage based on the difference between the two cases.

As described above, in the fuel vapor processing apparatus according to the modified example of the second embodiment, the control apparatus operates the pressure of the pump while operating the passage switching valve to the second operating position when the blocking valve is opened. The value at which the atmospheric pressure converges is taken as the second reference value. In addition, when the atmospheric pressure does not become larger than the second reference value when the pump is pressurized while operating the passage switching valve to the first operation position, the control device, the fuel tank, the first passage, the canister, the second It is determined that air leakage has occurred in the passage, the blocking valve, or the third passage.
Thereby, the air leak in a fuel tank, a 1st channel | path, a canister, a 2nd channel | path, a sealing valve, or a 3rd channel | path can be detected similarly to 2nd Embodiment.

(Other embodiments)
In another embodiment of the present invention, the control device may not have an air leak detection function. In short, it is only necessary to have a function of operating the pressure-increasing / decreasing means so that the tank-side pressure and the atmosphere-side pressure become equal prior to the opening of the block valve.
In other embodiments of the present invention, the block valve may be provided between the fuel tank and the canister.
In another embodiment of the present invention, the tank side pressure sensor may be provided between the fuel tank and the blocking valve.

In another embodiment of the present invention, the drive unit of the block valve is not limited to an electromagnetic type and may be an electric type.
In other embodiments of the present invention, the canister may not be provided.
Thus, the present invention is not limited to the above-described embodiments, and can be applied to various forms without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 1 ... Engine 4 ... Vehicle fuel tank 5 ... Intake passage 10, 80 ... Fuel vapor processing apparatus 21 ... 1st passage (passage)
23 ... 2nd passage (passage)
25 ... 3rd passage (passage)
27 ... 4th passage (passage)
40 ... Sealing valve 46 ... Valve member 48 ... Second pressure receiving surface 47 ... First pressure receiving surface 49 ... Solenoid (electric drive unit)
60... Pump (pressure increasing / decreasing means)
65 ... Tank side pressure sensor 70 ... Atmosphere side pressure sensor 75 ... Control device Pa ... Atmosphere side pressure Pt ... Tank side pressure

Claims (6)

A fuel vapor processing apparatus for supplying and processing fuel vapor generated in a fuel tank for a vehicle to an intake passage of an engine,
An atmosphere communication path capable of communicating with the atmosphere inside the vehicle fuel tank;
A purge passage capable of communicating the air communication passage with the intake passage;
A sealing valve comprising: a valve member capable of opening and closing the atmosphere communication path; and an electric drive unit for opening and closing the valve member;
A tank side pressure sensor for detecting a tank side pressure acting on a first pressure receiving surface of the valve member on the fuel tank side;
An atmospheric pressure sensor for detecting atmospheric pressure acting on the second pressure receiving surface on the atmospheric side of the valve member;
A pressure adjusting unit provided on the atmosphere side with respect to the valve member, and capable of pressurizing and depressurizing a space on the atmosphere side with respect to the valve member of the atmosphere communication path when the blocking valve is closed;
A control device for controlling the pressure-increasing and depressurizing means so that the air-side pressure and the tank-side pressure become equal prior to the opening of the block valve;
A fuel vapor processing apparatus comprising:   The control device operates the pressure increasing / decreasing means so that the atmospheric pressure increases when the atmospheric pressure is smaller than the tank pressure, and the atmospheric pressure decreases so that the atmospheric pressure decreases when the atmospheric pressure is larger than the tank pressure. 2. The fuel vapor processing apparatus according to claim 1, wherein the pressure increasing / decreasing means is operated.   The control device calculates a pressure difference between the tank-side pressure and the atmospheric-side pressure when a valve opening command for the blockade valve is given, and when the absolute value of the pressure difference is larger than a predetermined threshold, The fuel vapor processing apparatus according to claim 1, wherein the fuel vapor processing apparatus is operated and opens the block valve when an absolute value of the pressure difference is equal to or less than the threshold value.   When a predetermined time has elapsed from the start of the operation of the pressure increasing / decreasing means, the control device determines whether the pressure difference between the valve member and the pressure increasing / decreasing means is greater than the threshold. The fuel vapor processing apparatus according to claim 3, wherein it is determined that air leakage has occurred. A first branch passage connected to the atmosphere side with respect to the pressure increasing / decreasing means in the atmosphere communication passage;
A first port provided in a section between the blocking valve and the pressure increasing / decreasing means in the atmosphere communication path, connected to the blocking valve side of the section, and a second port connected to the pressure increasing / decreasing means side of the section. A three-way valve having a port and a third port connected to the first branch passage, and disconnecting the first port and the third port while communicating the first port and the second port A passage switching valve that operates in a first operating position and a second operating position that allows the first port and the third port to communicate with each other while blocking the first port and the second port;
One end of the atmospheric communication passage is connected between the block valve and the passage switching valve, and the other end is connected between the passage switching valve and the pressure increasing / decreasing means of the atmospheric communication passage. A second branch passage having a portion;
Further comprising
The controller is
When the blocking valve is opened, a value at which the atmospheric pressure converges when the pressure increasing / decreasing means is operated to reduce the pressure while operating the passage switching valve to the second operating position is set as the first reference value, and the passage switching valve When the atmospheric pressure does not become smaller than the first reference value when the pressure increasing / decreasing means is operated under reduced pressure while operating the first operating position,
Or
When the blockade valve is opened, a value at which the atmospheric pressure converges when the pressure increasing / decreasing means is pressurized while operating the passage switching valve to the second operating position is set as a second reference value, and the passage switching is performed. When the atmospheric pressure does not become larger than the second reference value when the pressure increasing / decreasing means is pressurized while operating the valve to the first operating position,
The fuel vapor processing apparatus according to any one of claims 1 to 4, wherein it is determined that an air leak has occurred on the fuel tank side with respect to the blocking valve.   The fuel vapor according to any one of claims 1 to 5, further comprising a canister provided between the fuel tank and the pressure increasing / decreasing means, and adsorbing the fuel vapor generated in the fuel tank. Processing equipment.

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