JP3518220B2 - Evaporative fuel processing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention adsorbs evaporated fuel (vapor) of an internal combustion engine to an adsorbent in a canister and releases the adsorbed fuel to an intake system of the internal combustion engine under a predetermined operating condition. The present invention relates to an evaporative fuel treatment device that burns by burning.

[0002]

2. Description of the Related Art An internal combustion engine for a vehicle is disclosed in JP-A-7-10.
As disclosed in Japanese Patent No. 3084, etc., in order to prevent the evaporated fuel in the fuel tank from being released to the atmosphere, the evaporated fuel is once adsorbed by the adsorbent in the canister and adsorbed while the vehicle is running. There is one equipped with an evaporative fuel processing device that regenerates the adsorbent by sucking fuel into the intake passage and burning it.

[0003]

Evaporative fuel is generated not only when the fuel temperature rises as the engine operates or when the fuel temperature rises as the outside air temperature rises, but also when fuel is supplied to the fuel tank. It also occurs when you are.

By the way, the adsorption capacity of the canister is limited, and even if the evaporated fuel is introduced into the saturated canister, the evaporated fuel is not adsorbed. In particular, since the amount of evaporated fuel generated is extremely large during fuel refueling, even if the canister is saturated, if the fuel tank continues to be refueled, vaporized fuel that cannot be adsorbed may pass through the canister and leak to the atmosphere.

The present invention has been made in view of the above problems of the prior art, and the problem to be solved by the present invention is to stop the refueling when the canister becomes saturated, or When the canister becomes almost saturated, the evaporated fuel is guided to the auxiliary canister to prevent the evaporated fuel from leaking to the atmosphere.

[0006]

The present invention adopts the following means in order to solve the above problems. (1) The present invention includes a fuel tank and a canister that communicates with the fuel tank via an evaporated fuel passage and adsorbs the evaporated fuel in the fuel tank. The adsorbed fuel in the canister is stored under predetermined operating conditions. In an evaporative fuel processing apparatus for purging an intake system of an internal combustion engine, a saturation degree detecting means for detecting a saturation degree of the canister, and the fuel when the saturation degree detected by the saturation degree detecting means becomes larger than a reference value. An evaporative fuel treatment apparatus, comprising: an oil supply stop means for stopping fuel supply to a tank.

In this evaporative fuel treatment system, when the canister saturation detected by the saturation detecting means becomes larger than the reference value while fuel is being supplied to the fuel tank, the fuel supply stopping means supplies the fuel. Stop. By setting the reference value to a value at which the evaporated fuel does not leak from the canister, it is possible to prevent the evaporated fuel from leaking to the atmosphere during refueling.

The saturation detecting means in the present invention can be constituted by a temperature detecting means for detecting a temperature change of the canister. This is because the adsorbent is accompanied by heat generation when adsorbing the evaporated fuel.

Further, the oil supply stopping means in the present invention can be constituted by a communication cutoff means for connecting or disconnecting the canister and the atmosphere.

(2) The present invention comprises a fuel tank and a canister which communicates with the fuel tank via an evaporated fuel passage and adsorbs the evaporated fuel in the fuel tank, and the canister in the canister under predetermined operating conditions. In an evaporated fuel processing device for purging adsorbed fuel into an intake system of an internal combustion engine, the canister is composed of a main canister and an auxiliary canister, and a refueling determination means that determines whether or not fuel is being refueled in the fuel tank, Saturation degree detection means for detecting the saturation degree of the main canister, it is determined that the refueling during the refueling determination means,
When the detected saturation by the saturation detecting means is smaller than the reference value is blocked auxiliary canister from the fuel tank, and connection cutoff means for communicating the auxiliary canister and the fuel tank only when the saturation is greater than the reference value And an evaporated fuel processing device.

In this evaporative fuel processing system, the evaporative fuel in the fuel tank is usually adsorbed by the main canister when the fuel is being supplied to the fuel tank, but the saturation of the main canister detected by the saturation detecting means is used as a reference. Only when the value becomes larger than the value, the communication cutoff means connects the auxiliary canister and the fuel tank, and the evaporated fuel in the fuel tank is adsorbed by the auxiliary canister. By setting the reference value to a value at which the evaporated fuel does not leak from the main canister, it is possible to prevent the evaporated fuel from leaking from the main canister during refueling, and it is possible to continue refueling.

The saturation detecting means of the present invention can also be constituted by temperature detecting means for detecting the temperature change of the canister, and the refueling stopping means of the present invention also connects or disconnects the canister and the atmosphere. It is possible to use a communication cutoff means.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an evaporated fuel processing apparatus according to the present invention will be described below with reference to the drawings of FIGS. The embodiment described below is a mode applied to a gasoline engine for automobiles as an internal combustion engine.

[First Embodiment] FIG. 1 is a schematic configuration diagram of a first embodiment of an evaporated fuel processing apparatus 1 of the present invention. The evaporated fuel processing device 1 includes a fuel tank 2 and a canister 4.
And are connected via an evaporation line (evaporative fuel passage) 6 and a breather line (evaporative fuel passage) 8.

The canister 4 is provided with a filling chamber 10 at an intermediate portion and diffusion chambers 12 and 14 on both upper and lower sides of the filling chamber 10. The filling chamber 10 is filled with activated carbon 16 as an adsorbent, and a bimetal switch 18 is installed below the filling chamber 10. The bimetal switch 18 is sensitive to the temperature of the activated carbon 14, maintains OFF when the temperature is lower than the preset temperature, and turns ON when the temperature is higher than the preset temperature. The ON-OFF switching temperature of the bimetal switch 18 will be described in detail later.

In addition to the evaporation line 6 and the breather line 8, a purge line 20 is connected to the upper diffusion chamber 12 of the canister 4. This purge line 2
Reference numeral 0 is connected to an intake pipe (intake pipe) of an engine (not shown) via a purge control valve 21, and an engine control unit (hereinafter abbreviated as ECU) 100 controls the purge control valve 21 according to operating conditions of the engine. Then, the evaporated fuel adsorbed by the canister 4 is purged into the intake pipe of the engine.

The ECU 100 is mainly composed of a microcomputer, and has a central processing unit (CPU), a read-on memory (ROM), and a random access memory (RA).
M) and the like (none of which are shown). Various sensors such as a throttle sensor, an air-fuel ratio sensor, a rotation speed sensor, a water temperature sensor, and an air flow meter are connected to the ECU 100, and the ECU 100 controls the air-fuel ratio and the fuel injection based on signals supplied from these sensors. Performs various controls such as.

The lower diffusion chamber 14 of the canister 4 can be connected to or disconnected from the atmosphere by an electromagnetic opening / closing valve (communication disconnecting means) 22. This solenoid valve 22
Is a normally open type valve, which is electrically connected to the valve drive power source 24 via the bimetal switch 18, and opens when the bimetal switch 18 is OFF and closes when the bimetal switch 18 is ON.

A tank internal pressure control valve 26 is provided on the evaporation line 6.
Is provided. The tank internal pressure control valve 26 includes a first pressure chamber 28 that communicates with the atmosphere, a second pressure chamber 30 that communicates with the upper diffusion chamber 12 of the canister 4, and the fuel tank 2
And a third pressure chamber 32 that communicates with the second pressure chamber 30. The second pressure chamber 30 and the third pressure chamber 32 are separated from the first pressure chamber 28 by the diaphragm 34.

The diaphragm 34 is biased in the valve closing direction by a spring 36, and in the valve closed state, the second pressure chamber 3 is closed.
0 and the third pressure chamber 32 are shut off. The tank internal pressure control valve 26 opens against the elasticity of the spring 36 when the internal pressure of the fuel tank 2 becomes a positive pressure equal to or higher than the set value V ₁ , and the second pressure chamber 30 and the third pressure chamber 32 communicate with each other. The evaporated fuel in the fuel tank 2 is discharged to the canister 4 via the evaporation line 6.

The second pressure chamber 30 and the third pressure chamber 32 are also cut off by a back purge valve 38. That is, the back purge valve 38 has the spring 40.
When the internal pressure of the fuel tank 2 becomes smaller than a predetermined negative pressure value V ₂ (becomes larger as an absolute value), the valve is opened against the elasticity of the spring 40, The pressure chamber 30 and the third pressure chamber 32 communicate with each other to allow air to flow into the fuel tank 2 via the electromagnetic opening / closing valve 22, the canister 4, and the evaporation line 6.

A rollover valve 58 for preventing fuel from flowing into the canister 4 is provided at the connection port of the evaporation line 6 in the fuel tank 2.

On the other hand, the fuel tank 2 is equipped with a differential pressure valve 42 and an oil supply pipe 44. The differential pressure valve 42 has a first pressure chamber 46 that communicates with the atmosphere, a second pressure chamber 48 that communicates with the breather line 8, and a third pressure chamber 50 that communicates with the inside of the fuel tank 2, and the second pressure chamber 48 and the third pressure chamber 50 are separated from the first pressure chamber 46 by a diaphragm 52.

The diaphragm 52 is biased in the valve closing direction by a spring 54, and in the valve closed state, the second pressure chamber 4 is closed.
8 and the third pressure chamber 50 are shut off. This differential pressure valve 42 is
When the internal pressure of the fuel tank 2 becomes equal to or higher than the set value V ₃ during the refueling of the fuel tank 2, the valve is opened against the elasticity of the spring 54 and the second pressure chamber 48 and the third pressure chamber 50 communicate with each other. The evaporated fuel in the fuel tank 2 is discharged to the canister 4 through the breather line 8. The valve opening pressure of each valve is V ₁ > V ₃
It is set such that> atmospheric pressure> V ₂ .

A float valve 56 for preventing fuel from flowing into the canister 4 is provided at the mounting port of the differential pressure valve 42 in the fuel tank 2. A refueling gun 130 is inserted into a refueling pipe 44 provided in the fuel tank 2 when refueling the fuel tank 2. This refueling pipe 44
A check valve 43 for preventing the reverse flow of fuel from the fuel tank 2 is provided at the tip of the.

The refueling gun 130 is provided with an automatic refueling stop mechanism that automatically stops refueling when the fuel tank is full during refueling. This kind of refueling gun 13
An example of 0 will be described with reference to FIG.

When the fuel gun 130 shown in FIG. 2 is used, the communication pipe 44a is branched from the outer peripheral surface of the upper portion of the fuel supply pipe 44 and the tip thereof is communicated with the fuel tank 2, and the communication pipe 44a is connected.
Is set to the liquid level when the fuel tank 2 is full. Then, the seal material 45 is annularly installed on the inner surface of the oil supply pipe 44 located upstream of the branch portion of the communication pipe 44a.

The refueling gun 130 has a curved nozzle pipe 132, and the nozzle pipe 132 is the refueling pipe 4.
The outer side is thinned toward the tip side so that it can be sufficiently sealed by the sealing material 45 when it is inserted into 4.

Inside the nozzle pipe 132, a first opening / closing valve mechanism 134 is arranged on the upstream side of the bending portion, and a second opening / closing valve mechanism 152 is arranged on the downstream side. The first opening / closing valve mechanism 134 includes a valve seat 136, a valve body 138, a spring 140, and a rod 142. Valve seat 136
Is fixed to the inner surface of the nozzle pipe 132, and a flow path 136a is formed in the central portion thereof. This valve seat 1
The valve body 138 can be seated and separated from the valve 36.
Is urged in a direction toward the valve seat 136 (that is, a valve closing direction) by a spring 140 fixed to the nozzle pipe 132 by an appropriate method (not shown). The rod 142 is attached to the valve body 138, and the tip of the rod 142 penetrates the nozzle pipe 132 and extends outward.

An opening / closing lever 144, an actuator 146, and a grip 150 are provided outside the nozzle pipe 132. The opening / closing lever 144 is used for the actuator 14
No. 6 movable body 146a is rotatably attached to a rotation center shaft 148 attached via a rod 146b. The movable body 146 a of the actuator 146 is the negative pressure chamber 1
When a negative pressure is introduced to 46c, the opening / closing lever 144 moves to the left because it moves to the left in the figure.

The grip 150 has a spring 15
0a is attached and the opening / closing lever 144 is always urged downward in the figure. The refueling operator inserts the nozzle pipe 132 of the refueling gun 130 into the refueling pipe 44 until the seal member 45 sufficiently seals the nozzle pipe 132. Next, the opening / closing lever 144
The free end 144a of the claw 150 of the grip 150.
Rotate upward until it is located above b. At this time, since the negative pressure is not introduced into the negative pressure chamber 146c of the actuator 146, the rotation center shaft 148 is also at the right end position.

Here, the opening / closing lever 144 is formed so that when the rotation center shaft 148 is located at the right end, the free end portion 144a is hooked on the upper surface of the claw 150b when it is rotated upward. Therefore, even if the refueling worker releases his / her hand, the free end portion 144a of the opening / closing lever 144 is caught by the claw 150b and does not drop downward in the figure.

On the other hand, when the opening / closing lever 144 is rotated upward, the rod 14 of the first opening / closing valve mechanism 134 is started halfway.
Push 2 upwards. Therefore, the valve element 138 of the first on-off valve mechanism 134 connected to the rod 142 is separated from the valve seat 136, and the fuel flows downstream through the flow passage 136a formed in the center of the valve seat 136, Second
It reaches upstream of the on-off valve mechanism 152.

The second opening / closing valve mechanism 152 comprises a valve seat 154, a valve body 156 and a spring 158. The valve seat 154 is fixed to the inner surface of the nozzle pipe 132,
As shown in the figure, it has a flow path 154a that is expanded downstream,
An annular air passage 154b is formed inside. The annular air passage 154b has a plurality of oblique passages 154c.
Communicates with the wall surface of the flow path 154a by the actuator air passage 154d.
No. 6 negative pressure chamber 146c, and the outer peripheral pressure introducing passage 1
54e communicates with the space 156 between the nozzle pipe 132 and the oil supply pipe 44.

The valve body 156 can be seated on and away from the valve seat 154, and the valve body 156 is directed toward the valve seat 154 by a spring 158 fixed to the nozzle pipe 132 by a suitable method (not shown) (ie, closed). Valve direction).

The fuel that has reached the upstream side of the second on-off valve mechanism 152 has the flow passage 15 at the center of the valve seat 154 of the second on-off valve mechanism 152.
4a, the spring 158 is pushed out to secure an outlet, reaches the downstream side of the second opening / closing valve mechanism 152, then flows out from the nozzle pipe 132, and flows into the inside of the fuel tank 2 through the oil supply pipe 44.

At this time, since the outlet of the communication pipe 44a is not blocked by the liquid surface of the fuel, the air dragged when the fuel flows out of the nozzle pipe 132 and flowing into the fuel tank 2 is again communicated with the communication pipe 44a. Through the nozzle pipe 13
2 to the outer part, so that the pressure in the space 156 does not become negative.

Therefore, the negative pressure chamber 146c of the actuator 146 does not become negative pressure, the rotation center shaft 148 is also kept at the right end position, and the free end portion 144a of the opening / closing lever 144 is prevented from coming off from the claw 150b. Open / close valve mechanism 1
The valve 34 is kept open, and the fuel continues to flow.

Eventually, when fuel is injected up to the full tank,
The liquid level of the fuel rises and closes the outlet of the communication pipe 44a. Then, the air that is dragged when the fuel flows out of the nozzle pipe 132 and flows into the fuel tank 2 cannot flow back to the outside portion of the nozzle pipe 132 through the communication pipe 44 a again, and the pressure of the space 156 is reduced. Becomes negative pressure.

Then, the negative pressure chamber 1 of the actuator 146 is
46c also becomes negative pressure, the rotation center shaft 148 moves to the left, and the free end portion 144a of the opening / closing lever 144 has the claw 150b.
Then, the opening / closing lever 144 is rotated downward by the urging force of the spring 150a and moved to the position indicated by the broken line in the figure.

Therefore, through the rod 142, the valve seat 1
The valve element 138 of the first on-off valve mechanism 134, which has been separated from the valve 36, is pushed downward in the figure by the urging force of the spring 140, and the flow passage 136a of the valve seat 136 is closed to stop the inflow of fuel. As a result, the valve body 156 of the second opening / closing valve mechanism 152 also moves so as to close the inside of the flow path 154a.

When the refueling operator pulls out the refueling gun 130, the check valve 43 operates and fuel is supplied to the fuel tank 2.
It is prevented from being sucked into the oil supply pipe 44 from the inside.

The automatic refueling stop mechanism of the refueling gun is not limited to the above-mentioned one. For example, when the fuel tank 2 becomes full while refueling, the float valve 56 is set to be closed, and the air in the fuel tank 2 cannot be exhausted due to the closing of the float valve 56 or the like. It is also possible to use a refueling gun equipped with an automatic refueling stop mechanism that automatically stops refueling when the pressure rises. In that case, the communication pipe 44a is connected to the fuel tank 2.
Need not be provided.

The evaporative fuel processing system 1 normally operates as follows. Normally, the bimetal switch 18 is off
Then, the electromagnetic opening / closing valve 22 is opened, and the diffusion chamber 14 below the canister 4 is in communication with the atmosphere.

The vaporized fuel generated by the temperature rise of the fuel in the fuel tank 2 is guided to the tank internal pressure control valve 26 via the evaporation line 6, and the pressure in the fuel tank 2 is kept at a predetermined value V.
_When it reaches ₁ or more, it is discharged to the canister 4 together with air and adsorbed on the activated carbon 16. Then, the clean air from which the evaporated fuel has been removed is discharged to the atmosphere through the electromagnetic opening / closing valve 22.

The temperature of the fuel in the fuel tank 2 drops and the fuel
The pressure in the material tank 2 is the predetermined value V ₁Decompress to below
And discharge of evaporated fuel from the fuel tank 2 to the canister 4.
Stops.

When the temperature of the fuel in the fuel tank 2 further decreases and the pressure in the fuel tank 2 reaches a predetermined negative pressure value V ₂ , the back purge valve 38 opens and the electromagnetic opening / closing valve 22 and the canister 10 are opened. Atmosphere is introduced into the fuel tank 2 through the evaporation line 6 and the negative pressure in the fuel tank 2 is controlled to a predetermined pressure to prevent damage to the fuel tank 2.

When the purge condition is satisfied during the operation of the engine, the ECU 100 opens the purge control valve 21,
The negative pressure of the intake pipe is passed through the purge line 20 to the canister 4
Will be introduced to. As a result, the atmosphere is guided to the canister 4 via the electromagnetic on-off valve 22, the evaporated fuel adsorbed on the activated carbon 16 is purged, and the purged evaporated fuel is purged.
Supply to the engine via 0.

While purging fuel vapor to the engine,
The ECU 100 controls the purge control valve 21 so that the purge flow rate does not affect the exhaust emission due to the purge gas.
Duty control of the opening degree of.

On the other hand, when the engine is stopped and the refueling gun 130 is inserted from the refueling pipe 44 to refuel the fuel tank 2, the refueling fuel increases the pressure in the fuel tank 2. At this time, when the pressure in the fuel tank 2 reaches a predetermined pressure value V ₃ , the differential pressure valve 42 opens, and the vaporized fuel due to the fueled fuel or the vaporized fuel that has been filled in the fuel tank 2 before the fueling together with the breather. Canister 4 via line 8
And is adsorbed on the activated carbon 16. Then, the clean air from which the evaporated fuel has been removed is discharged to the atmosphere through the electromagnetic opening / closing valve 22.

By the way, the relationship between the adsorbed amount of the evaporated fuel and the leakage amount in the activated carbon 16 is, as shown in FIG. 3, there is no leakage of the evaporated fuel until the adsorbed amount reaches β, but the adsorbed amount is β (below. , The amount of adsorption is referred to as a leakage limit value β), and then the amount of leakage increases as the amount of adsorption increases, and when the saturation of the activated carbon 16 approaches 100%, almost no adsorption occurs. To go through. In the figure, α indicates the amount of adsorption when the degree of saturation is 100%.

Therefore, the adsorption of the evaporated fuel in the canister 4 starts from the activated carbon 16 located on the inlet side of the canister 4 (the side closer to the diffusion chamber 12 on the upper side), and as the activated carbon 16 on the inlet side saturates, it sequentially exits ( The activated carbon 16 on the lower side (closer to the diffusion chamber 14) is transferred. FIG. 4 shows a state in which the saturated state of the activated carbon 16 shifts from the inlet side of the canister 4 to the outlet side thereof. In the figure, the adsorption zone K indicates the portion where the evaporated fuel is being adsorbed.

Further, the activated carbon 16 generates heat along with the adsorption of the evaporated fuel, and the temperature rise width of the activated carbon 16 is proportional to the adsorption amount.
Therefore, by monitoring the temperature of the lower portion of the filling chamber 10 in the canister 4, it is possible to detect whether or not the adsorption zone K has reached the lower portion of the filling chamber 10, and the canister 4 can be detected.
The saturation degree of can be detected.

If the fuel refueling is stopped when the adsorption amount of the activated carbon 16 in the lower part of the filling chamber 10 reaches the leakage limit value β, it is possible to prevent the evaporated fuel from leaking from the canister 4 at the time of refueling. .

Therefore, in this embodiment, the activated carbon 16
A bimetal switch 18 is used in which the temperature (for example, 60 ° C.) of the activated carbon 16 when the vaporized fuel adsorbs the vaporized fuel and the adsorption amount reaches the leakage limit value β is set to the ON-OFF switching temperature.

Using this bimetal switch 18,
When the adsorption zone K reaches the vicinity of the bimetal switch 18 and the adsorption amount of the activated carbon 16 near the bimetal switch 18 reaches the leakage limit value β, the bimetal switch 18 is turned on and the electromagnetic opening / closing valve 22 is closed. You can

When the electromagnetic opening / closing valve 22 is closed, the canister 4 cannot exhaust to the atmosphere, so that the evaporated fuel does not leak from the canister 4, and at the same time, the air in the fuel tank 2 cannot be exhausted. When the air in the fuel tank 2 cannot exhaust, the refueling gun 130 exhibits the same behavior as when the fuel tank 2 is full of fuel,
As a result, the space 156 between the refueling pipe 44 and the nozzle pipe 132 of the refueling gun 130 becomes negative pressure, and as described above, the first opening / closing valve mechanism 134 and the second opening / closing valve mechanism 152 of the refueling gun 130 are closed. Valve to automatically stop refueling.

After the automatic refueling is stopped, the refueling gun 13
No. 0 opening / closing lever 56 is pulled up again to open the first opening / closing valve mechanism 1
Even if the valve 34 is opened and the fuel refueling is continued, the refueling cannot be refueled because the automatic refueling stop operation is executed as described above unless the electromagnetic opening / closing valve 22 is opened. As a result, it is possible to reliably prevent the evaporated fuel from leaking from the canister 4 to the atmosphere.

When the temperature of the activated carbon 16 is lowered, the bimetal switch 18 is turned off and the electromagnetic opening / closing valve 22 is opened. As a result, it becomes possible to regenerate the activated carbon 16 by sucking the evaporated fuel adsorbed by the activated carbon 16 of the canister 4 into the intake pipe of the engine through the purge line 20.

In this embodiment, the bimetal switch 18 constitutes the saturation detecting means, and the electromagnetic opening / closing valve 22.
Constitutes the refueling stop means.

[Second Embodiment] FIG. 5 is a schematic configuration diagram of a second embodiment of the evaporated fuel processing apparatus 1 of the present invention. The structure of the evaporated fuel processing apparatus 1 in the second embodiment is the same as that of the first embodiment except for a part. Hereinafter, only the points of the second embodiment different from the first embodiment will be described, and the same parts as those of the first embodiment are designated by the same reference numerals in the drawings and the description thereof will be omitted. Although the refueling gun 130 is omitted in FIG. 5,
The refueling gun 130 has the same structure and operation as those of the first embodiment.

Evaporative fuel treatment system 1 of the second embodiment
Is the bimetal switch 18 in the first embodiment.
The solenoid on-off valve 22 and the valve drive power source 24 are not provided. In the second embodiment, a cylinder chamber 60 is formed below the filling chamber 10 of the canister 4, and the cylinder chamber 6 is formed.
0 penetrates the diffusion chamber 14 and projects outward. Inside the cylinder chamber 60, there are a spring 62 whose base end is fixed to the inner part of the cylinder chamber 60, and a piston 64 which is attached to the tip of the spring 62 and is capable of sliding airtightly on the inner peripheral surface of the cylinder chamber 60. It is stored.

The spring 62 is made of a shape memory alloy or a shape memory resin and contracts below a set temperature and expands above the set temperature, at which the activated carbon 16 adsorbs vaporized fuel. The temperature of the activated carbon 16 is set so that the amount of adsorption reaches the leakage limit value β.

Further, the diffusion chamber 14 below the canister 4 can be connected or disconnected from the atmosphere via a diaphragm type flow control valve 66. Flow control valve 6
6 is a first pressure chamber 68 communicating with the atmosphere, and a canister 4
Of the first pressure chamber 6 and the second pressure chamber 70 communicating with the diffusion chamber 14 and the third pressure chamber 72 communicating with the cylinder chamber 60.
8 and the second pressure chamber 70 are separated from the third pressure chamber 72 by a diaphragm 74.

The diaphragm 74 is urged in the valve closing direction by its own elasticity, and in the valve closed state, the first pressure chamber 6 is closed.
8 and the second pressure chamber 70 are shut off. This flow control valve 66
Is opened against the elasticity when the pressure in the canister 4 becomes equal to or higher than a set value as the pressure in the fuel tank 2 increases.
The pressure chamber 68 and the second pressure chamber 70 communicate with each other, and the fuel tank 2
The evaporated fuel inside is discharged to the canister 4 through the evaporation line 6 or the breather line 8.

Further, the cylinder chamber 60 and the flow control valve 66
The third pressure chamber 72 is communicated with the two-way valve 76. The two-way valve 76 includes a first pressure chamber 78 and a second pressure chamber 80 that are separated by a partition wall, and the first pressure chamber 78 is the cylinder chamber 6
0 and the third pressure chamber 72 of the flow control valve 66, and the second pressure chamber 80 communicates with the atmosphere.

The first pressure chamber 78 and the second pressure chamber 80 can be connected or shut off by two valve bodies 82 and 84. Both valve bodies 82, 84 are biased in a valve closing direction by a spring (not shown), and both valve bodies 82, 84 are closed when the first pressure chamber 78 is substantially at atmospheric pressure. The valve body 82 opens when the first pressure chamber 78 has a positive pressure, and the valve body 84 opens when the first pressure chamber 78 has a negative pressure.

However, the dynamic characteristic of the two-way valve 76 is that when the valve body 82 is opened by positive pressure, the holding time of positive pressure is lengthened and when the valve body 84 is opened by negative pressure. The pressure chamber 78 is set so that it can be quickly returned to atmospheric pressure.

In the evaporated fuel processing apparatus 1, the pressure in the fuel tank 2 rises at the time of refueling the fuel to open the flow rate control valve 66, and the evaporated fuel is adsorbed by the activated carbon 16 to remove the evaporated fuel. Air is discharged to the atmosphere via the flow control valve 66.

Then, at the time of refueling, the adsorption zone K reaches the position of the cylinder chamber 60 in the canister 4 and the cylinder chamber 6
The adsorption amount of activated carbon 16 around 0 becomes the leakage limit value β,
When the temperature in the cylinder chamber 60 reaches the set temperature, the spring 64 momentarily expands and lowers the piston 64. As a result, the space communicating with the third pressure chamber 72 of the flow control valve 66 is pressurized, pressing the diaphragm 74 of the flow control valve 66 in the valve closing direction, and closing the flow control valve 66.

When the flow control valve 66 is closed, the canister 4 cannot be exhausted to the atmosphere, so that the evaporated fuel does not leak from the canister 4, and at the same time, the air in the fuel tank 2 cannot be exhausted. When the air in the fuel tank 2 cannot exhaust, the refueling gun 130 exhibits the same behavior as when the fuel tank 2 is full of fuel,
As a result, the space 156 between the refueling pipe 44 and the nozzle pipe 132 of the refueling gun 130 becomes negative pressure, and as described above, the first opening / closing valve mechanism 134 and the second opening / closing valve mechanism 152 of the refueling gun 130 are closed. Valve to automatically stop refueling.

Further, since the dynamic characteristic of the two-way valve 76 is set as described above, the flow control valve 66 is kept closed for a predetermined time. Therefore, even if the opening / closing lever 56 of the refueling gun 130 is pulled up again and the first opening / closing valve mechanism 134 is opened to continue the fuel refueling after the automatic refueling stop, the automatic refueling stop is performed as described above unless the flow control valve 66 is opened. It cannot be refueled because the action is performed.
As a result, it is possible to reliably prevent the evaporated fuel from leaking from the canister 4 to the atmosphere.

When the temperature of the activated carbon 16 decreases, the temperature in the cylinder chamber 60 decreases, so that the spring 64 contracts and the piston 64 rises. As a result, the space communicating with the third pressure chamber 72 of the flow rate control valve 66 is depressurized to a negative pressure, the valve body 84 of the two-way valve 76 opens, and the third pressure chamber 72 quickly becomes atmospheric pressure. Thus, the flow control valve 66 can be opened. As a result, it becomes possible to regenerate the activated carbon 16 by sucking the evaporated fuel adsorbed by the activated carbon 16 of the canister 4 into the intake pipe of the engine through the purge line 20.

In this embodiment, the spring 62 constitutes saturation detecting means, and the flow rate control valve 66 and the two-way valve 76 are provided.
Constitutes the refueling stop means.

[Third Embodiment] FIG. 6 is a schematic configuration diagram of a third embodiment of the evaporated fuel processing apparatus 1 of the present invention. The configuration of the evaporated fuel processing apparatus 1 in the third embodiment is the same as that of the first embodiment except for a part. Hereinafter, only the points of the third embodiment that differ from the first embodiment will be described, and the same parts as those of the first embodiment will be assigned the same reference numerals in the drawings and description thereof will be omitted. Although the refueling gun 130 is omitted in FIG. 6,
The refueling gun 130 has the same structure and operation as those of the first embodiment.

Evaporative fuel treatment system 1 of the third embodiment
Is the bimetal switch 18 in the first embodiment.
The valve drive power source 24 is not provided. In the evaporated fuel processing apparatus 1 according to the third embodiment, the temperature sensor 8 is provided below the filling chamber 10 of the canister 4 instead of the bimetal switch 18.
6 is attached, and the detection signal of the temperature sensor 86 is input to the ECU 100.

The tip of the oil supply pipe 44 is housed inside the fuel lid 90 which can be opened by the lid opener 88. The lid opener 88 has an open sensor 92 for detecting that the lid opener 88 has been opened.
Is provided, and the detection signal of the open sensor 92 is the ECU 1
00 is input.

In the fuel vapor processing apparatus 1 of this embodiment, the ECU 100 controls the opening / closing drive of the electromagnetic opening / closing valve 22 based on the detection signals of the temperature sensor 86 and the open sensor 92. The opening / closing drive processing routine of the electromagnetic opening / closing valve 22 will be described below with reference to FIG. 7.

First, the ECU 100 determines whether the fuel lid 90 is closed (step 20).
0). When the fuel lid 90 is closed, it is determined that fuel is not being supplied to the fuel tank 2 and the electromagnetic on-off valve 22 is opened (step 210) to set the state in which the evaporated fuel can be adsorbed by the canister 4 and the evaporated fuel. Make the intake pipe purgeable.

When the fuel lid 90 is open, it is determined that fuel is being supplied to the fuel tank 2, and the detection signal of the temperature sensor 86 is set as the temperature T of the activated carbon 16 on the outlet side of the canister 4 in the RAM of the ECU 100. (Step 220).

Next, it is judged whether or not the temperature T is higher than the judgment value Tc (step 230). Here, the judgment value Tc
Is the temperature of the activated carbon 16 when the activated carbon 16 adsorbs the evaporated fuel and the adsorption amount reaches the leakage limit value β.

When the temperature T is determined to be equal to or lower than the determination value Tc, the electromagnetic opening / closing valve 22 is opened (step 240) and then the process returns to step 200. As a result, while the temperature T detected by the temperature sensor 86 during fuel refueling is equal to or lower than the determination value Tc, the electromagnetic on-off valve 22 is held in the open state, and refueling can be continued.

On the other hand, when it is determined that the temperature T is higher than the determination value Tc, the electromagnetic opening / closing valve 22 is closed (step 250) and then the process returns to step 200. As a result, the electromagnetic on-off valve 22 is kept closed while the temperature T detected by the temperature sensor 86 is higher than the determination value Tc during fuel refueling.

When the electromagnetic opening / closing valve 22 is closed, the canister 4 cannot exhaust to the atmosphere, so that the evaporated fuel does not leak from the canister 4, and at the same time, the air in the fuel tank 2 cannot be exhausted.

When the air in the fuel tank 2 cannot be exhausted, the refueling gun 130 exhibits the same behavior as when the fuel tank 2 is full of fuel. As a result, the refueling pipe 4
4 and the space 156 between the nozzle pipe 132 of the fuel gun 130 becomes negative pressure, and as described above, the fuel gun 130
The first opening / closing valve mechanism 134 and the second opening / closing valve mechanism 152 are closed, and the fuel supply is automatically stopped.

After the automatic refueling is stopped, the refueling gun 13
No. 0 opening / closing lever 56 is pulled up again to open the first opening / closing valve mechanism 1
Even if the valve 34 is opened and the fuel refueling is continued, the refueling cannot be refueled because the automatic refueling stop operation is executed as described above unless the electromagnetic opening / closing valve 22 is opened. As a result, it is possible to reliably prevent the evaporated fuel from leaking from the canister 4 to the atmosphere.

When fuel refueling is stopped and the fuel lid 90 is closed, the routine proceeds to step 210, where the electromagnetic opening / closing valve 22 is opened and the evaporated fuel can be purged into the intake pipe.

In this embodiment, the temperature sensor 8
6 and the ECU 100 form a saturation detecting means, and the electromagnetic opening / closing valve 22 and the ECU 100 form a refueling stopping means.

[Fourth Embodiment] FIG. 8 is a schematic configuration diagram of a fourth embodiment of the evaporated fuel processing apparatus 1 of the present invention. The configuration of the evaporated fuel processing apparatus 1 in the fourth embodiment is the same as that of the third embodiment except for a part. Hereinafter, only the points of the fourth embodiment different from the third embodiment will be described, and the same parts as those of the third embodiment are designated by the same reference numerals in the drawings and the description thereof will be omitted. Although the refueling gun 130 is omitted in FIG. 8,
The refueling gun 130 has the same structure and operation as those of the first embodiment.

Evaporative fuel treatment system 1 of the fourth embodiment
Does not include the electromagnetic opening / closing valve 22 in the third embodiment, and the diffusion chamber 14 below the canister 4 is always open to the atmosphere. Further, another solenoid opening / closing valve 94 is provided in the middle of the breather line 8.

In the evaporated fuel processing apparatus 1 of this embodiment, the ECU 100 controls the opening / closing drive of the electromagnetic opening / closing valve 94 based on the detection signals of the temperature sensor 86 and the open sensor 92. The opening / closing drive processing routine of the electromagnetic opening / closing valve 94 will be described below with reference to FIG.

First, the ECU 100 determines whether the fuel lid 90 is closed (step 30).
0). If the fuel lid 90 is closed, it is determined that fuel is not being supplied to the fuel tank 2, and the electromagnetic opening / closing valve 94 is closed (step 310).

Even when the electromagnetic on-off valve 94 is closed, the diffusion chamber 14 below the canister 4 is always open to the atmosphere, so the evaporated fuel can be adsorbed by the canister 4 as well. It is also possible to purge.

When the fuel lid 90 is open, it is determined that the fuel is being supplied to the fuel tank 2, and the detection signal of the temperature sensor 86 is set as the temperature T of the activated carbon 16 on the outlet side of the canister 4 in the RAM of the ECU 100. (Step 320).

Next, it is judged whether or not the temperature T is higher than the judgment value Tc (step 330). This determination value Tc is the same as in the third embodiment, and is the temperature of the activated carbon 16 when the activated carbon 16 adsorbs the evaporated fuel and the adsorption amount reaches the leakage limit value β.

When it is determined that the temperature T is equal to or lower than the determination value Tc, the electromagnetic opening / closing valve 94 is opened (step 340) and then the process returns to step 300. As a result, while the temperature T detected by the temperature sensor 86 during fuel refueling is equal to or lower than the determination value Tc, the electromagnetic opening / closing valve 94 is held in the open state, and refueling can be continued.

On the other hand, when it is determined that the temperature T is higher than the determination value Tc, the electromagnetic opening / closing valve 94 is closed (step 310). As a result, the temperature sensor 8
While the temperature T detected in 6 is higher than the determination value Tc, the electromagnetic opening / closing valve 94 is kept closed.

When the electromagnetic opening / closing valve 94 is closed, the canister 4 cannot exhaust to the atmosphere, so that the evaporated fuel does not leak from the canister 4, and at the same time, the air in the fuel tank 2 cannot be exhausted. When the air in the fuel tank 2 cannot exhaust, the refueling gun 130 exhibits the same behavior as when the fuel tank 2 is full of fuel,
As a result, the space 156 between the refueling pipe 44 and the nozzle pipe 132 of the refueling gun 130 becomes negative pressure, and as described above, the first opening / closing valve mechanism 134 and the second opening / closing valve mechanism 152 of the refueling gun 130 are closed. Valve to automatically stop refueling.

After the automatic refueling is stopped, the refueling gun 13
No. 0 opening / closing lever 56 is pulled up again to open the first opening / closing valve mechanism 1
Even if the valve 34 is opened and the fuel refueling is continued, the refueling cannot be refueled because the automatic refueling stop operation is executed as described above unless the electromagnetic opening / closing valve 94 is opened. As a result, it is possible to reliably prevent the evaporated fuel from leaking from the canister 4 to the atmosphere.

[Fifth Embodiment] FIG. 10 is a schematic configuration diagram of a fifth embodiment of the evaporated fuel processing apparatus 1 of the present invention. The structure of the evaporated fuel processing apparatus 1 in the fifth embodiment is the same as that of the third embodiment except for a part. Hereinafter, only the points of the fifth embodiment that differ from the third embodiment will be described, and the same parts as those of the third embodiment will be assigned the same reference numerals in the drawings and description thereof will be omitted. Further, although the refueling gun 130 is omitted in FIG. 10, the refueling gun 130 has the same structure and operation as those of the first embodiment.

Evaporative Fuel Treatment Device 1 of Fifth Embodiment
Has two canisters, a main canister 4A and an auxiliary canister 4B. The main canister 4A corresponds to the canister 4 in the third embodiment, and the auxiliary canister 4B is connected to the main canister 4A.

The auxiliary canister 4B is the main canister 4A.
Similarly, the filling chamber 98 filled with activated carbon 96 as an adsorbent, and the diffusion chambers 1 provided on the upper and lower sides of the filling chamber 98.
00 and 102, and the lower diffusion chamber 102 is connected to the atmosphere. Diffusion chamber 100 above auxiliary canister 4B
Is connected to the upper diffusion chamber 12 of the main canister 4A via a bypass line 104 and a butterfly valve 106. The butterfly valve 106 is a valve that is provided above the main canister 4A and that opens and closes according to the pressure in the diffusion chamber 12 of the main canister 4A. That is, the butterfly valve 1
06 is biased in the valve closing direction by a spring (not shown), and is kept closed when the pressure in the diffusion chamber 12 is lower than a predetermined value, and is opened when the pressure is higher than the predetermined value. In addition, the butterfly valve 106 has a hole in its central portion so that a small amount of air can flow even when the butterfly valve 106 is closed.

In the evaporated fuel processing apparatus 1 of this embodiment, the evaporated fuel in the fuel tank 2 is normally guided to and adsorbed to the main canister 4A, but a large amount is generated during refueling of the fuel tank 2. When the saturation of the activated carbon 16 in the main canister 4A increases due to the evaporated fuel of the main canister 4A and the evaporated fuel is about to leak from the main canister 4A to the atmosphere, the auxiliary canister 4B replaces the main canister 4A before leaking.
Are adapted to adsorb evaporated fuel.

The switching of the canister is based on the detection signals of the temperature sensor 86 and the open sensor 92.
0 controls the opening / closing drive of the electromagnetic opening / closing valve 22.
Hereinafter, the opening / closing drive processing routine of the electromagnetic opening / closing valve 22 will be described with reference to FIG.
Will be described with reference to.

First, the ECU 100 determines whether the fuel lid 90 is closed (step 40).
0). If the fuel lid 90 is closed, it is determined that fuel is not being supplied to the fuel tank 2 and step 4 is performed.
In step 10, it is determined whether the valve closing flag is set.

If the valve closing flag is not set, the electromagnetic opening / closing valve 22 is opened (step 420), and
The valve closing flag is reset (step 430). The valve closing flag is not set in the initial routine.

When the solenoid on-off valve 22 is open,
The pressure inside the diffusion chamber 12 on the upper side of the main canister 4A is small, and the diaphragm valve 106 is kept closed. Therefore, the evaporated fuel sent out from the fuel tank 2 together with the air passes through the main canister 4A and is adsorbed by the activated carbon 16, so that the clean air from which the evaporated fuel is removed becomes the electromagnetic on-off valve 2.
It is exhausted to the atmosphere through 2. During this time, the evaporated fuel does not flow into the auxiliary canister 4B. Also,
When the electromagnetic on-off valve 22 is opened, the evaporated fuel adsorbed in the main canister 4A is also purged when purging the adsorbed evaporated fuel in the intake pipe.

On the other hand, if it is determined in step 400 that the fuel lid 90 is open, the fuel tank 2
It is determined that the fuel is being refueled, and the detection signal of the temperature sensor 86 is written in the RAM of the ECU 100 as the temperature T of the activated carbon 16 on the outlet side of the canister 4 (step 44).
0).

Next, it is determined whether or not the temperature T is higher than the determination value Tc (step 450). Here, the judgment value Tc
Is the temperature of the activated carbon 16 when the activated carbon 16 adsorbs the evaporated fuel and the adsorption amount reaches the leakage limit value β.

When it is determined that the temperature T is equal to or lower than the determination value Tc, the electromagnetic opening / closing valve 22 is opened (step 460) and then the process returns to step 400. As a result, while the temperature T detected by the temperature sensor 86 during fuel refueling is equal to or lower than the determination value Tc, the electromagnetic on-off valve 22 is held in the open state, and refueling can be continued.

During this time, the evaporated fuel sent out together with the air from the fuel tank 2 is adsorbed by the activated carbon 16 through the main canister 4A, and the clean air from which the evaporated fuel is removed passes through the electromagnetic on-off valve 22 to the atmosphere. Exhausted. Further, as described above, since the diaphragm valve 106 is kept closed during this period, the evaporated fuel does not flow into the auxiliary canister 4B.

If the fuel supply is completed and the fuel lid 90 is closed without the temperature T exceeding the determination value Tc, it is determined in step 400 that the lid is closed, and the routine described above (step 400 → step 41) is performed.
0 → step 420 → step 430 → END).

Further, in step 450, the temperature T is determined by the judgment value T
If it is determined that the value is larger than c, the solenoid opening / closing valve 22
Is closed (step 470), the valve closing flag is set (step 480), and the process returns to step 400. As a result, the electromagnetic on-off valve 22 is kept closed while the temperature T detected by the temperature sensor 86 is higher than the determination value Tc during fuel refueling. As a result, the main canister 4A
The lower diffusion chamber 14 cannot be exhausted, and the evaporated fuel does not leak from the main canister 4A to the atmosphere.

When the electromagnetic on-off valve 22 is closed, the pressure inside the diffusion chamber 12 above the main canister 4A rises.
When the pressure exceeds a predetermined pressure value, the diaphragm valve 106 automatically opens, and as a result, the fuel tank 2
The evaporated fuel sent together with the air from the main canister 4A is guided to the auxiliary canister 4B from the diffusion chamber 12 of the main canister 4A through the bypass line 104 and adsorbed to the activated carbon 96 of the auxiliary canister 4B. Then, the clean air from which the evaporated fuel has been removed is exhausted to the atmosphere from the diffusion chamber 102 below the auxiliary canister 4B.

Therefore, even if the adsorbed amount of the activated carbon 16 near the outlet of the main canister 4A reaches the leakage limit value β during fuel refueling, the activated carbon 96 of the auxiliary canister 4B adsorbs the evaporated fuel, so refueling is performed during the refueling. Refueling can be continued without stopping, and during that time, evaporated fuel does not leak to the atmosphere.

By the way, the auxiliary canister 4B is only for assisting the main canister 4A, and after adsorbing the evaporated fuel, the auxiliary canister 4B is regenerated at an early stage and should be kept in standby for the next fuel refueling.

However, in this evaporative fuel processing system 1, as described above, when the electromagnetic opening / closing valve 22 is open, air circulates toward the main canister 4A and no air circulates through the auxiliary canister 4B. . Therefore, the evaporated fuel adsorbed by the auxiliary canister 4B cannot be purged unless it is purged after the fuel supply is completed and before the electromagnetic opening / closing valve 22 is opened.

Therefore, when the electromagnetic opening / closing valve 22 is returned to the open state after the fuel supply is completed, it is necessary to purge the evaporated fuel adsorbed by the auxiliary canister 4B before opening the electromagnetic opening / closing valve 22.

On the other hand, in this evaporative fuel processing system, since the lower diffusion chamber 4B of the auxiliary canister 4B is always in communication with the atmosphere, the negative pressure of the intake pipe is maintained while the electromagnetic opening / closing valve 22 is kept closed. When introduced into the canister 4A, the atmospheric air flows into the auxiliary canister 4B, passes through the bypass line 104, the hole provided in the diaphragm valve 106, and further through the diffusion chamber 12 and the purge line 20 of the main canister 4A. Therefore, the evaporated fuel adsorbed by the auxiliary canister 4B can be purged.

Therefore, in this embodiment, when the electromagnetic opening / closing valve 22 is returned to the open state after the fuel supply is completed, the opening timing of the electromagnetic opening / closing valve 22 is controlled to be delayed, so that the evaporation adsorbed by the auxiliary canister 4B is evaporated. I try to purge the fuel.

In the valve opening delay control, the purge amount from the start of the purge is integrated when the evaporated fuel is first purged after the fuel supply is completed, and when the integrated purge amount reaches the specified value, the electromagnetic opening / closing valve 22 is turned on. It is realized by opening the valve.

That is, when the main canister 4A is switched to the auxiliary canister 4B during the fuel refueling as described above, and after the refueling of the fuel is completed and the fuel lid 90 is closed, it is determined in step 400 that the lid is closed. , And proceeds to step 410, where it is determined whether the valve closing flag is set. Here, since the valve closing flag has already been set at step 480, the routine proceeds from step 410 to step 490, where it is determined whether the accumulated amount of harsh to the intake pipe has reached the specified purge amount. When the integrated purge amount does not reach the specified purge amount, the process returns to step 470 and the closed state of the electromagnetic opening / closing valve 22 is maintained.

When the integrated purge amount reaches the specified purge amount, the routine proceeds to step 420, the electromagnetic opening / closing valve 22 is opened, and the valve closing flag is reset (step 43).
0). After the solenoid on-off valve 22 opens, the main canister 4
The evaporated fuel adsorbed on the activated carbon 16 of A is sucked into the intake pipe.

In the valve opening delay control of the electromagnetic on-off valve 22, the purge concentration in the purge line 20 is detected by the HC sensor, and the solenoid on-off valve 22 is opened when the purge concentration becomes lower than the predetermined purge concentration. It can also be realized by doing so.

In this embodiment, the temperature sensor 8
6 and the ECU 100 form a saturation detecting means, and the electromagnetic opening / closing valve 22, the diaphragm valve 106 and the ECU 100 form a communication cutoff means for connecting or disconnecting the fuel tank 2 and the auxiliary canister 4B.

[Sixth Embodiment] FIG. 12 is a schematic configuration diagram of a sixth embodiment of the evaporated fuel processing apparatus 1 of the present invention. The configuration of the evaporated fuel processing apparatus 1 in the sixth embodiment is the same as that of the fifth embodiment except for a part. Hereinafter, only the points of difference between the sixth embodiment and the fifth embodiment will be described, and the same parts as those of the fifth embodiment will be designated by the same reference numerals in the drawings and will not be described. Further, although the refueling gun 130 is omitted in FIG. 12, the refueling gun 130 has the same structure and operation as those of the first embodiment.

Evaporative Fuel Treatment Device 1 of Sixth Embodiment
Has no diaphragm valve 106 in the main canister 4A, a bypass line 104 connected to the upper diffusion chamber 100 of the auxiliary canister 4B is connected to the breather line 8, and another electromagnetic opening / closing valve is provided in the middle of the bypass line 104. 108 is provided.

Hereinafter, in the sixth embodiment, the electromagnetic on-off valve 22 will be referred to as the atmosphere on-off valve 22, and the electromagnetic on-off valve 108
Is referred to as a canister switching valve 108. In the evaporated fuel processing apparatus 1 of this embodiment, the ECU 100 controls the opening / closing drive of the atmosphere opening / closing valve 22 and the canister switching valve 108 based on the detection signals of the temperature sensor 86 and the open sensor 92. By this valve opening / closing drive control, the saturated degree of the activated carbon 16 in the main canister 4A increases due to a large amount of evaporated fuel generated during refueling of the fuel tank 2, and the evaporated fuel is likely to leak from the main canister 4A to the atmosphere. In this case, the flow path of the evaporated fuel is automatically switched before it leaks so that the auxiliary canister 4B adsorbs the evaporated fuel.

The open / close drive processing routine for the atmosphere open / close valve 22 and the canister switching valve 108 will be described below with reference to FIG. First, the ECU 100 determines whether the fuel lid 90 is closed (step 500).

If the fuel lid 90 is closed, it is determined that fuel is not being supplied to the fuel tank 2, and the routine proceeds to step 510, where it is determined whether the valve switching flag is set.

When the valve switching flag is not set, the atmosphere switching valve 22 is opened, the canister switching valve 108 is closed (step 520), and the valve switching flag is reset (step 530). Incidentally, the valve switching flag is not set in the initial routine.

When the atmosphere opening / closing valve 22 is opened and the canister switching valve 108 is closed, the evaporated fuel sent out together with the air from the fuel tank 2 is adsorbed by the activated carbon 16 through the main canister 4A, and the evaporated fuel is evaporated. The clean air from which the air has been removed is exhausted to the atmosphere through the atmosphere opening / closing valve 22.
Also, when purging the evaporated fuel to the intake pipe, the evaporated fuel adsorbed by the main canister 4A is also purged. And
Evaporative fuel does not flow into the auxiliary canister 4B,
The evaporated fuel adsorbed by the auxiliary canister 4B will not be purged into the intake pipe.

On the other hand, if it is determined in step 500 that the fuel lid 90 is open, the fuel tank 2
It is determined that the fuel is being refueled, and the detection signal of the temperature sensor 86 is written in the RAM of the ECU 100 as the temperature T of the activated carbon 16 on the outlet side of the canister 4 (step 54).
0).

Next, it is judged whether or not the temperature T is higher than the judgment value Tc (step 550). Here, the judgment value Tc
Is the temperature of the activated carbon 16 when the activated carbon 16 adsorbs the evaporated fuel and the adsorption amount reaches the leakage limit value β.

When it is determined that the temperature T is equal to or lower than the determination value Tc, the atmosphere opening / closing valve 22 is opened and the canister switching valve 108 is closed (step 560), after which the process returns to step 500. Thus, while the temperature T detected by the temperature sensor 86 during refueling is equal to or lower than the determination value Tc, the atmosphere opening / closing valve 22 is held in the open state and the canister switching valve 108 is opened.
Will be kept closed and refueling can be continued.

During this time, the evaporated fuel sent out together with the air from the fuel tank 2 is adsorbed by the activated carbon 16 through the main canister 4A, and the clean air from which the evaporated fuel has been removed passes through the atmosphere opening / closing valve 22 to the atmosphere. Exhausted. Further, during this time, the evaporated fuel does not flow into the auxiliary canister 4B.

When the fuel replenishment is completed and the fuel lid 90 is closed without the temperature T exceeding the determination value Tc, it is determined in step 500 that the lid is closed, and the routine described above (step 500 → step 51) is performed.
0 → step 520 → step 530 → END).

Further, at step 550, the temperature T is judged to be the judgment value T.
If it is determined that the value is larger than c, the atmosphere opening / closing valve 22
Is closed and the canister switching valve 108 is opened (step 570), the valve switching flag is set (step 580), and the process returns to step 500. As a result, the temperature T detected by the temperature sensor 86 during refueling is determined by the determination value T
While it is larger than c, the atmosphere opening / closing valve 22 is kept closed and the canister switching valve 108 is kept open. As a result, the diffusion chamber 14 below the main canister 4A cannot exhaust gas, and the evaporated fuel does not leak from the main canister 4A to the atmosphere.

When the atmosphere opening / closing valve 22 is closed and the canister switching valve 108 is opened, the evaporated fuel sent out from the fuel tank 2 together with the air cannot flow into the main canister 4A, and passes through the bypass line 104 to the auxiliary canister. 4B, activated carbon 96 of auxiliary canister 4B
Is adsorbed on. Then, the clean air from which the evaporated fuel has been removed is exhausted to the atmosphere from the diffusion chamber 102 below the auxiliary canister 4B.

Therefore, even if the adsorbed amount of the activated carbon 16 in the vicinity of the outlet of the main canister 4A reaches the leakage limit value β during fuel refueling, the activated carbon 96 of the auxiliary canister 4B adsorbs the evaporated fuel, so refueling is performed during the refueling. Refueling can be continued without stopping, and during that time, evaporated fuel does not leak to the atmosphere.

By the way, the auxiliary canister 4B in the evaporative fuel processing apparatus 1 is only for assisting the main canister 4A, and after adsorbing the evaporative fuel, the auxiliary canister 4B is regenerated at an early stage to refuel the fuel next time. I want to keep it on standby.

To this end, when the evaporated canister is adsorbed by the auxiliary canister 4B, when the evaporated fuel is purged for the first time after the fuel supply is completed, the atmosphere opening / closing valve 22 is kept closed and the canister switching valve 108 is turned on. It is preferable that the fuel vapor adsorbed by the auxiliary canister 4B be purged before the fuel vapor adsorbed by the main canister 4A by holding the valve open state.

Therefore, in this embodiment, when the evaporated fuel is adsorbed by the auxiliary canister 4B, the atmosphere switching valve 22 is closed and the canister switching valve 108 is opened after the fuel supply is completed. Delay controlled.

This delay control of the valve switching timing is performed by integrating the purge amount from the start of the purge when the evaporated fuel is first purged after the fuel refueling is completed, and when the accumulated purge amount reaches the specified value, the atmosphere opening / closing valve is opened. It is realized by opening the valve 22 and closing the canister switching valve 108.

That is, when the main canister 4A is switched to the auxiliary canister 4B during the fuel refueling as described above, and after the refueling of the fuel is completed and the fuel lid 90 is closed, it is determined in step 500 that the lid is closed. , And proceeds to step 510, where it is determined whether the valve switching flag is set. Here, since the valve switching flag has already been set in step 580, step 510
From step 590 to step 590, it is determined whether or not the accumulated amount of hurge to the intake pipe has reached the specified purge amount. If the accumulated purge amount does not reach the specified purge amount,
Returning to step 570, the closed state of the atmosphere opening / closing valve 22 is maintained, and the open state of the canister switching valve 108 is maintained.

When the integrated purge amount reaches the specified purge amount, the routine proceeds to step 520, where the atmosphere opening / closing valve 22 is opened, the canister switching valve 108 is closed, and the valve switching flag is reset (step 530). ). After the atmosphere opening / closing valve 22 is opened and the canister switching valve 108 is closed, the evaporated fuel adsorbed on the activated carbon 16 of the main canister 4A is sucked into the intake pipe.

The delay control of the valve switching timing is as follows.
It can also be realized by detecting the purge concentration in the purge line 20 with an HC sensor and switching the opening / closing of the atmosphere open / close valve 22 and the canister switching valve 108 when the purge concentration becomes lower than a predetermined purge concentration.

In this embodiment, the temperature sensor 8
6 and the ECU 100 constitute saturation detecting means, and the atmosphere opening / closing valve 22, the canister switching valve 108, and the ECU 100 constitute communication disconnecting means for connecting or disconnecting the fuel tank 2 and the auxiliary canister 4B.

[Correction] In the evaporated fuel processing apparatus 1 of the third to sixth embodiments described above, a temperature sensor is used as the saturation detecting means of the canister, and based on the detection signal of this temperature sensor. The refueling stopping means or the communication cutoff means is electrically controlled, but in this case, in order to improve accuracy and effectively use the canister, it is possible to make the following corrections.

<Correction 1> As described above, the activated carbon generates heat due to the adsorption of the evaporated fuel, and the temperature of the activated carbon rises as the adsorption amount increases. To be precise, however, it is the amount of change in temperature (heat generation amount) that correlates with the amount of adsorbed fuel vapor, and the temperature of activated carbon during adsorption is the same as the temperature of activated carbon before adsorption, even if the amount of adsorption is the same. It differs slightly depending on.

Therefore, if the refueling is stopped or the canister is switched when the temperature T detected by the temperature sensor 86 reaches a predetermined temperature as described in the third to sixth embodiments, the adsorbed amount of activated carbon is reduced. Refueling may be stopped or the canister may be switched before the leakage limit value β is reached. With this, although the evaporated fuel can be prevented from leaking from the canister, it cannot be said that the activated carbon is effectively used.

Therefore, in each cycle, the temperature change amount ΔT is obtained from the temperature difference between the temperature Tt detected by the temperature sensor 86 and the temperature Ti detected by the temperature sensor 86 at the start of fuel supply (Equation 1). It is determined from ΔT whether or not the amount of activated carbon adsorbed has reached the leakage limit value β, and based on this determination, refueling can be stopped or the canister can be switched. It is possible to prevent leakage of evaporated fuel from the inside.

[0153]

## EQU1 ## ΔT = Tt-Ti

FIG. 14 is a diagram showing the correlation between the amount of evaporated fuel adsorbed on activated carbon and the amount of temperature change ΔT.

<Correction 2> There is a detection delay in the temperature sensor 86, and it takes a driving time to open and close the electromagnetic on-off valves 22, 94 and 108. Therefore, due to these factors, the temperature change amount ΔT is corrected in consideration of the delay time so that the timing of refueling stop or canister switching is not delayed, and the adsorbed amount of activated carbon is the leakage limit from the corrected temperature change amount ΔTβ. It is also possible to determine whether or not the value β has been reached, and to stop refueling or switch the canister based on this determination. This correction formula is shown in Equation 2.

[0156]

## EQU2 ## ΔTβ = ΔT + (dT / dt) × τ = Tt−T
i + (dT / dt) × τ

Here, (dT / dt) is the temperature change speed, which is proportional to the moving speed of the adsorption zone K. τ is a delay time set for each evaporated fuel processing system. By performing this correction, it is possible to more reliably prevent the vaporized fuel from leaking.

<Correction 3> In the third to sixth embodiments, the temperature sensor 86 is installed at the bottom of the canisters 4 and 4A,
Although it is arranged closest to the diffusion chamber 14 which is the outlet, it may not be installed at the bottom at the bottom due to various restrictions when it is actually used as a device.

In this case, the activated carbon 16 located near the temperature sensor 86 is detected based on the detection signal of the temperature sensor 86.
Is determined to reach the leakage limit value β, and the time required for the adsorption zone K to reach immediately before the diffusion chamber 14 is expressed by a formula 3
And the predicted arrival time td has elapsed,
It may be corrected to stop the fuel supply or switch the canister.

[0160]

## EQU00003 ## td = L / v

Here, L is from the temperature sensor 86 to the filling chamber 1
It is the distance to the bottom of 0. v is the moving speed of the adsorption zone K and is proportional to the temperature change speed (dT / dt) when the adsorption amount is the leakage limit value β. FIG. 15 is a diagram showing the correlation between the temperature change rate (dT / dt) and the moving speed v of the adsorption zone K when the adsorption amount is predetermined, and the two are proportional.

With this correction, the activated carbon 16 filled on the outlet side of the temperature sensor 86 can also be effectively used for adsorbing the evaporated fuel.

[Other Embodiments] In the evaporated fuel processing apparatus 1 according to the third to sixth embodiments described above, the temperature sensor is used as the saturation detecting means. It is also possible to configure the degree detecting means with an HC sensor. That is, an HC sensor is installed near the outlets of the canisters 4 and 4A, the HC concentration at the outlets of the canisters 4 and 4A is detected by the HC sensor, and the amount of activated carbon 16 adsorbed near the outlets is detected from the HC concentration or changes in the HC concentration. (Saturation degree) may be detected, and fuel refueling stop or canister switching may be performed based on this saturation degree.

Further, even when the HC sensor is used as the saturation detecting means, the same corrections as the correction 1, the correction 2, and the correction 3 described above can be performed.

The sixth to sixth embodiments described above are also applicable.
In the evaporative fuel treatment apparatus 1 of the embodiment, it is determined whether or not the fuel is being refueled depending on whether or not the fuel lid 90 is in the open state, and the open sensor 92 constitutes the refueling determination means. The means is a liquid level sensor for detecting the liquid level of the fuel in the fuel tank 2, a fuel temperature sensor for detecting the temperature of the fuel in the fuel tank 2, a vapor concentration sensor for detecting the purge vapor concentration in the purge line 20, and the like. It is also possible to configure with.

For example, in the case of the liquid level sensor, it is judged whether or not the liquid level of the fuel in the fuel tank 2 has risen based on the detection signal of the liquid level sensor detected with a time lag, and the liquid level is If it rises, it is determined that refueling is in progress.

Further, in the case of the fuel temperature sensor, the temperature change amount of the fuel in the fuel tank 2 is calculated based on the detection signal of the fuel temperature sensor detected with a time difference, and the temperature change amount is larger than the judgment value. In this case, it is determined that refueling is in progress.

According to this determination principle, the change in the fuel temperature in the fuel tank 2 is extremely gentle under normal operating conditions, but during the fuel refueling, the fuel temperature in the fuel tank 2 is affected by the refueling fuel temperature. Is based on the rapid change of. Whether the fuel temperature rises or falls depends on the fuel temperature in the fuel tank 2 before refueling and the refueling fuel temperature.

In the case of the vapor concentration sensor, the increase amount of the purge vapor concentration is obtained based on the detection signal of the vapor concentration sensor detected with a time lag. When the increase amount of the purge vapor concentration is larger than the judgment value, refueling is in progress. To determine.

The principle of this judgment is that a large amount of vapor (evaporated fuel) is generated from the refueling fuel during fuel refueling and is discharged to the canister 4 through the breather line 8, so the purge vapor concentration in the purge line 20 is the fuel. It is based on the fact that it increases more rapidly than when it is not refueling.

[0171]

As described above, according to the present invention,
A saturation detecting means for detecting the saturation of the canister; and a refueling stopping means for stopping refueling of fuel to the fuel tank when the saturation detected by the saturation detecting means exceeds a reference value. Thus, it is possible to stop refueling before evaporative fuel leaks from the canister to the atmosphere, and it is possible to reliably prevent evaporative fuel from leaking from the canister to the atmosphere during refueling. It

Further, according to the present invention, the main canister,
Auxiliary canister, refueling determination means for determining whether or not fuel is being supplied to the fuel tank, saturation degree detection means for detecting the saturation degree of the main canister, and refueling determination means for determining saturation When the saturation degree detected by the means is less than the reference value, the auxiliary canister is shut off from the fuel tank, and when the saturation degree is greater than the reference value, the auxiliary canister and the communication cutoff means for communicating the fuel tank are provided. Before the evaporated fuel leaks from the main canister to the atmosphere, it is possible to switch from the main canister to the auxiliary canister and adsorb the evaporated fuel with the auxiliary canister.
There is an excellent effect that it is possible to surely prevent the evaporated fuel from leaking from the canister during the fuel refueling without stopping the refueling.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram in a first embodiment of an evaporated fuel processing device of the present invention.

FIG. 2 is a cross-sectional view showing an example of a refueling gun including an automatic refueling stop mechanism.

FIG. 3 is a diagram showing a correlation between an adsorption amount of activated carbon with respect to evaporated fuel and a leakage amount.

FIG. 4 is a diagram showing a state in which an adsorption zone moves from an inlet side to an outlet side in a canister.

FIG. 5 is a schematic configuration diagram in a second embodiment of an evaporated fuel processing device of the present invention.

FIG. 6 is a schematic configuration diagram of a third embodiment of an evaporated fuel processing device of the present invention.

FIG. 7 is a flowchart showing a valve opening / closing drive processing routine in a third embodiment of the evaporated fuel processing apparatus of the present invention.

FIG. 8 is a schematic configuration diagram of a fourth embodiment of an evaporated fuel processing device of the present invention.

FIG. 9 is a flowchart showing a valve opening / closing drive processing routine in a fourth embodiment of the evaporated fuel processing apparatus of the present invention.

FIG. 10 is a schematic configuration diagram of a fifth embodiment of an evaporated fuel processing apparatus of the present invention.

FIG. 11 is a flow chart showing a valve opening / closing drive processing routine in a fifth embodiment of the evaporated fuel processing apparatus of the present invention.

FIG. 12 is a schematic configuration diagram of a vaporized fuel processing apparatus according to a sixth embodiment of the present invention.

FIG. 13 is a flow chart showing a valve opening / closing drive processing routine in a sixth embodiment of the evaporated fuel processing apparatus of the present invention.

FIG. 14 is a diagram showing a correlation between an adsorption amount of activated carbon with respect to evaporated fuel and a temperature change amount.

FIG. 15 is a diagram showing a relationship between a temperature change rate of activated carbon during adsorption of evaporated fuel and a movement rate of an adsorption zone in a canister.

[Explanation of symbols]

1 Evaporative Fuel Processing Device 2 Fuel Tank 4 Canister 4A Main Canister 4B Auxiliary Canister 6 Evaporative Line (Evaporative Fuel Passage) 8 Breather Line (Evaporative Fuel Passage) 18 Bimetal Switch (Saturation Determining Means) 22 Electromagnetic On / Off Valve (Fuel Stopping Means, Communication) Shut-off means 62 Spring (saturation detection means) 66 Flow rate control means (lubrication stop means) 76 Two-way valve (lubrication stop means) 86 Temperature sensor (saturation detection means) 94 Electromagnetic on-off valve (lubrication stop means) 100 Engine control Unit (saturation detection means, oil supply stop means, communication cutoff means) 106 Diaphragm valve (communication cutoff means) 108 Canister switching valve (communication cutoff means)

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Claims (4)

(57) [Claims] 1. A fuel tank, and a canister which communicates with the fuel tank via an evaporated fuel passage to adsorb the evaporated fuel in the fuel tank, and the adsorbed fuel in the canister is adsorbed in the internal combustion engine under predetermined operating conditions. In the evaporative fuel processing apparatus for purging to the intake system, the saturation degree detecting means for detecting the saturation degree of the canister, and to the fuel tank when the saturation degree detected by the saturation degree detecting means becomes larger than a reference value. And a fuel supply stopping means for stopping fuel supply of the fuel. 2. The evaporative fuel treatment apparatus according to claim 1, wherein the saturation detection means is constituted by temperature detection means for detecting a temperature change of the canister. 3. The evaporative fuel treatment apparatus according to claim 1, wherein the refueling stopping means is a communication cutoff means that connects or disconnects the canister and the atmosphere. 4. A fuel tank, and a canister that communicates with the fuel tank via an evaporated fuel passage to adsorb the evaporated fuel in the fuel tank, and the adsorbed fuel in the canister under predetermined operating conditions In the evaporative fuel treatment apparatus for purging into the intake system, the canister includes a main canister and an auxiliary canister, a refueling determination means for determining whether or not fuel is being refueled in the fuel tank, and a saturation of the main canister. Saturation detection means for detecting the degree of saturation, and the refueling determination means determines that refueling is in progress, and when the saturation degree detected by the saturation degree detection means is smaller than a reference value, the auxiliary canister is shut off from the fuel tank and saturated. Fuel vapor processing, comprising: a communication cutoff means for communicating the auxiliary canister and the fuel tank only when the degree is larger than a reference value. apparatus.