JPH05180108A - Fuel tank device - Google Patents

Abstract

PURPOSE:To prevent a fuel from being excessively filled in a tank of the fuel tank apparatus for an internal combustion engine, by permitting flow-out of fuel to the canister side, at the time when the tank is not in full and when the internal tank pressure is at a first set pressure level, and permitting it at the time when the tank is in full and when the internal tank pressure is at a second set pressure level equal to or higher than the first one. CONSTITUTION:A ventilation passage 46 is connected to a surge tank 8, and a separator 54 and a canister 22 are provided. Further, branch passages 50, 52 are communicated with a fuel tank 20 via check valves 62, 64, respectively, to form a pressure control means 24. An open/close valve 68 is disposed between the canister 22 and the surge tank 8. The check valve 62 is so set as to be opened by a first set pressure (for example 235mmAq) while the check valve 64 is so set as to be opened by a second set pressure (for example, 253mAq) higher than the first set pressure. As a result, flow-out of fuel to the canister 22 side is permitted by the first check valve 62 when the tank 22 is not in full of fuel, and is permitted by the second check valve 64 when the tank is in full of fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank device, and more particularly to a fuel tank capable of controlling the pressure in the fuel tank to a value lower than a lower first preset pressure in recent years and preventing overfilling of the fuel tank. Regarding the device.

[0002]

2. Description of the Related Art In a fuel tank for storing fuel of an internal combustion engine, when vaporized fuel generated in the fuel tank is released into the atmosphere, a large amount of hydrocarbon (HC) is contained in the vaporized fuel, so that the atmosphere is high. It is one of the causes of pollution and also leads to loss of fuel. Therefore, as a means for solving such a problem, a canister containing an adsorbent such as activated carbon once adsorbs and holds vaporized fuel generated in a fuel tank or the like, and the vaporized fuel adsorbed and held in the canister is stored in the internal combustion engine. There is a fuel tank device for releasing and releasing the fuel tank to supply it to the internal combustion engine during operation.

As such a fuel tank device, there is one disclosed in Japanese Patent Application Laid-Open No. 2-3029. The fuel tank device disclosed in this publication is provided with a ventilation passage having one end opened in the fuel tank and the other end opened to the atmosphere through an opening / closing valve and a canister, and a breather passage defining a full liquid level of the fuel tank. In a fuel tank device including a fuel tank device, a seal member for closing a gap between the fuel tank and a fuel filler is provided in the fuel tank, a valve that is opened when fuel is supplied is provided in the breather passage, and the other end of the breather passage is provided with the on-off valve and the canister. It is provided so as to communicate with an air passage between the fuel tank and the fuel tank, and prevents the evaporative fuel from being released into the atmosphere during refueling and seals the refueling port to enable smooth refueling.

[0004]

By the way, as shown in FIG. 6, in the conventional fuel tank device 302, the fuel tank 304 is provided with an oil supply passage 306 communicating one end side thereof, and the other end side of this oil supply passage 306 is provided. A fuel filler port 308 is provided, and a breather passage 310 is provided which communicates one end side with the fuel tank 304 and communicates the other end side with the fuel filler passage 306 in the vicinity of the fuel filler port 308, and a fuel tank 304 and a canister (not shown). A check valve 314 is provided in the ventilation path 312 communicating with the above. The check valve 314 is set to open when the pressure inside the fuel tank 304 exceeds a predetermined pressure.

However, in the recent fuel tank device 302, the regulation on the leakage of the evaporated fuel becomes strict,
There is a standard that the pressure in the fuel tank 304 should be controlled to a set pressure (for example, 253 mmAq) lower than the predetermined pressure or less. Further, when the pressure in the fuel tank 304 exceeds the set pressure (253 mmAq), when the refueling cap 316 detachably provided in the refueling port 308 to refuel the fuel tank 304 is removed,
It is required to prevent the evaporated fuel in the fuel tank 304 from being released to the atmosphere.

The set pressure of 253 mmAq is the height of the water column (Aq). If the height of the water column (Aq) is α1 and the height of the mercury column (Hg) is α2, the water column (Aq)
The relationship between the height α1 of q) and the height α2 of the mercury column (Hg) is given by α1 / 13.6 (mmHg) = α2 (mmAq).

Therefore, the conventional fuel tank device 302
When the pressure in the fuel tank 304 exceeds the predetermined pressure, the check valve 314 is opened to close the pressure in the fuel tank 304 to allow the pressure in the fuel tank 304 to flow out to the canister side. The pressure is controlled to be equal to or lower than a predetermined pressure which is higher than a set pressure (253 mmAq) which is a standard of time. Therefore, in the conventional fuel tank device, the pressure in the fuel tank 304 is set to a set pressure (253 mmA) which is lower than the conventional predetermined pressure and is a standard.
q) There are inconveniences that cannot be managed below.

Further, the set pressure (2), which is a standard for the recent time when the pressure in the fuel tank 304 is lower than the conventional predetermined pressure, is set.
When the check valve 314 is set to open when the pressure exceeds 53 mmAq), the fuel tank 304
When the pressure in the fuel tank 304 exceeds a set pressure (253 mmAq) lower than the conventional pressure during refueling, the check valve 314 is opened to allow the pressure in the fuel tank 304 to flow to the canister side. It will be. Therefore, the pressure in the fuel tank 304 is controlled to be lower than the set pressure (253 mmAq) lower than the conventional pressure by the check valve 314 to allow outflow to the canister side. There is a disadvantage that overfilling cannot be prevented.

[0009]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a fuel tank for storing the fuel of an internal combustion engine, and adsorbs and holds the evaporated fuel in the fuel tank and also adsorbs and holds it. A canister for releasing and releasing evaporated fuel to supply to the internal combustion engine is provided, and when the fuel tank is in an unfilled state, the pressure in the fuel tank is controlled to be below a first set pressure. When the pressure exceeds the first set pressure, it allows outflow to the canister side, and when the fuel tank is full, the pressure in the fuel tank is set to a second set pressure higher than the first set pressure. In order to manage the pressure below, a pressure management means is provided for permitting outflow to the canister side when the pressure in the fuel tank exceeds the second set pressure.

[0010]

According to the structure of the present invention, when the fuel tank is in an unfilled state, the pressure in the fuel tank is controlled by the pressure control means so as to control the pressure in the fuel tank to the first set pressure or less. When the pressure exceeds the first set pressure, the outflow to the canister side is allowed, and when the fuel tank is full, the pressure in the fuel tank is controlled to be equal to or lower than the second set pressure higher than the first set pressure. Therefore, when the pressure in the fuel tank exceeds the second set pressure, the outflow to the canister side is allowed. As a result, the fuel tank device can manage the pressure in the fuel tank at the first set pressure or lower and the second set pressure or lower. Therefore, by setting the first set pressure lower than in the conventional case, It is possible to control the internal pressure to be equal to or lower than the first set pressure that is lower than the conventional pressure. Further, when the fuel tank is filled with fuel, when the fuel tank is in a full state, the pressure in the fuel tank is controlled to be equal to or lower than the second set pressure higher than the first set pressure, so that the second set pressure is high as in the conventional case. Can be managed below.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described in detail with reference to the drawings. FIGS. 1 to 3 show a first embodiment of the present invention. In the figure, 2 is an internal combustion engine, 4 is an air cleaner, 6 is a throttle valve, 8 is a surge tank, and 10 is a surge tank.
Is an intake passage, 12 is a combustion chamber, 14 is an exhaust passage, and 16 is a fuel injection valve. The fuel injection valve 16 is provided in the intake passage 10 of the internal combustion engine 2 so as to be directed toward the combustion chamber 12 and is connected to the fuel tank 20 of the fuel tank device 18 through a fuel passage (not shown). The fuel of the internal combustion engine 2 stored in the fuel tank 20 is sent to the fuel injection valve 16 via a fuel passage by a fuel pump (not shown), and is supplied to the combustion chamber 12 together with air for combustion. The exhaust gas generated by the combustion is exhausted through the exhaust passage 14.

The fuel tank device 18 is provided with the fuel tank 20 for storing the fuel of the internal combustion engine 2, and adsorbs and holds the evaporated fuel in the fuel tank 20 and adsorbs and holds the evaporated fuel in the internal combustion engine 2. A canister 22 is provided for releasing and releasing to supply.

Further, in the fuel tank device 18, when the fuel tank 20 is in an unfilled state, the pressure in the fuel tank 20 is controlled so that the pressure in the fuel tank 20 is controlled to be equal to or lower than the first set pressure P1. When the first set pressure P1 is exceeded, the outflow to the canister 22 side is allowed and the fuel tank 20
Is full, the pressure in the fuel tank 20 is set to the first
In order to manage the pressure within the second set pressure P2 higher than the set pressure P1, the pressure inside the fuel tank 20 is set to the second set pressure P2.
Pressure control means 24 is provided to allow outflow to the canister 22 side when the pressure exceeds.

More specifically, as shown in FIGS. 1 to 3, the fuel tank 20 of the fuel tank device 18 is provided with an oil supply passage 28 which communicates with a communication port 26 on one end side. The other end of the oil supply passage 28 is inclined upward, and an oil supply port 30 is provided at the tip thereof, and an oil supply cap 32 is detachably provided on the oil supply port 30. Further, the fuel tank 20 has a breather passage 36 communicating with the breather inlet 34 on one end side.
Is provided. The breather passage 36 is inclined upward at the other end, bent at the upper end 38 and inclined downward, and the breather outlet 40 at the tip of the downward inclination is provided so as to communicate with the vicinity of the oil supply port 30 of the oil supply passage 28. ..

The canister 22 contains an adsorbent 42 such as activated carbon, which temporarily adsorbs and holds the evaporated fuel generated in the fuel tank 20 and the like, and separates the adsorbed and held evaporated fuel during operation of the internal combustion engine 2. It is released and supplied to the internal combustion engine 2.

The pressure managing means 24 includes the intake passage 1
0, for example, the surge tank 8 downstream of the throttle valve 6
Is provided with a ventilation path 46 that communicates with a ventilation port 44 on one end side, and the other end side of this ventilation path 46 is provided with a first branch point 48.
The branch air passage 50 and the second branch air passage 52 are provided so as to be branched. Ventilation path 4 from branch point 48 to surge tank 8
6, the separator 54 and the canister 22 are sequentially provided from the side of the branch point 48. The canister 22 is provided with an atmosphere port 22A.

The first branch air passage 50 has a first end on the other end side.
The length of the vent hole 56 from the ceiling surface 58 of the fuel tank 20 is L1.
It is opened at the position where it is lowered. The second branch ventilation path 52 is provided with a second ventilation port 60 on the other end side which is opened to the ceiling surface 58 of the fuel tank 20. The first ventilation port 56 is opened at the same height as the position L0 where the breather inlet 34 is opened.

The first check valve 62 is opened in the first branch air passage 50 when the pressure in the fuel tank 20 exceeds a first set pressure P1 (for example, 253 mmAq or lower which is lower than a predetermined pressure of the prior art). Is installed. Further, the fuel tank 2 is installed in the second branch air passage 52.
The second set pressure P2 in which the pressure within 0 is higher than the first set pressure P1 (for example, 253 mmA which is the conventional predetermined pressure).
The second check valve 64 is provided so as to be opened when it exceeds (q or more). The first and second check valves 62 and 64 are two-way valves.

Therefore, the first set pressure P1 for opening the first check valve 62 and the second check valve 64 are set.
The second set pressure P2 at which the opening operation is performed is set to P1 <P2. That is, the second set pressure P2 at which the second check valve 64 opens is set higher than the first set pressure P1 at which the first check valve 62 opens. It should be noted that the first check valve 62 is opened first
Since the set pressure P1 is low, it is necessary to appropriately set the relationship between the liquid level in the fuel tank 20 and the liquid level in the fuel supply passage during refueling, and the height L2 in the illustrated example.

As a result, when the fuel tank 20 is in an unfilled state, the pressure control means 24 controls the pressure inside the fuel tank 20 by the first check valve 62 to the first set pressure P1.
In order to manage the following, when the pressure in the fuel tank 20 exceeds the first set pressure P1, the outflow to the canister 22 side is allowed, and when the fuel tank 20 is full, the second check valve 64 is used. When the pressure in the fuel tank 20 exceeds the second set pressure P2 in order to control the pressure in the fuel tank 20 to be equal to or lower than the second set pressure P2 which is higher than the first set pressure P1, the outflow to the canister 22 side is allowed. To do.

Reference numeral 66 is an auxiliary breather passage. The auxiliary breather passage 66 is provided at a position lower than the full height of the oil supply passage 28 by L2, and is located at a position lower than the first check valve 62 toward the first ventilation port 56.
The branch air passage 50 and the small breather inlet 34 from the upper end 38
It communicates with the breather passage 36 at the position descending to the side.

Further, an opening / closing valve 68 is provided in the air passage 44 extending from the canister 22 to the surge tank 8. The on-off valve 68 is controlled to open and close so that the evaporated fuel adsorbed and held by the canister 22 is released and released according to the operating state of the internal combustion engine 2 and is supplied to the combustion chamber 12 for combustion. In this embodiment, the opening / closing valve 68 is controlled to be opened / closed by the control unit 70 which inputs an operation state signal.

Next, the operation will be described. When the internal combustion engine 2 is operating, the fuel tank device 18 controls the opening / closing valve 68 to open / close by the control unit 70 to release the evaporated fuel adsorbed and held in the canister 22 according to the operating state of the internal combustion engine 2 to burn it. It is supplied to the chamber 12 and burned. Further, in the fuel tank device 18, when the internal combustion engine 2 is stopped, the control unit 70 controls the on-off valve 68 to close so that the evaporated fuel generated in the fuel tank 20 is adsorbed and held in the canister 22.

The fuel tank device 18 adjusts the pressure inside the fuel tank 20 to the first when the fuel tank 20 is in an unfilled state.
The check valve 62 controls the pressure to be equal to or lower than the first set pressure P1. As a result, when the pressure in the fuel tank 20 exceeds the first set pressure P1, it is allowed to flow out to the canister 22 side, so that the evaporated fuel flowing out from the fuel tank 20 can be adsorbed and held in the canister 22.

Fuel tank 2 having a reduced amount of stored fuel
When refueling to 0, as shown in FIG. 2, the refueling cap 32 attached to the refueling port 30 of the refueling passage 28 is removed and the refueling tool 72 is inserted into the refueling port 30. This allows
The oil supply port 30 of the oil supply passage 28 is closed by the oil supply tool 72.

The fuel supplied by the refueling tool 72 flows into the fuel tank 20 from the refueling passage 28 through the communication port 26. As a result, the pressure in the fuel tank 20 increases due to the inflowing fuel. At this time, when the fuel tank 20 is in an unfilled state, the pressure in the fuel tank 20 is the first pressure in the fuel tank 20 due to the first check valve 62.
When the pressure exceeds the set pressure P1, the outflow to the canister 22 side is allowed. That is, the pressure in the fuel tank 20 is the first
The check valve 62 controls the pressure to be equal to or lower than the first set pressure P1.

Therefore, the excess air due to the increase in the pressure in the fuel tank 20 due to the inflowing fuel reaches the fuel filler port 30 via the fuel filler passage 28 and the breather passage 36. At this time, when the pressure in the fuel tank 20 exceeds the first set pressure P1, the first check valve 62 allows the outflow to the canister 22 side, so the evaporated fuel flowing out from the fuel tank 20 is adsorbed to the canister 22. Can be held.

When the amount of fuel stored in the fuel tank 20 increases during fueling to the fuel tank 20 and reaches the height position of the first vent hole 56 on the other end side of the first branch air passage 50, as shown in FIG. As shown in, the first ventilation port 56 is closed to be in a full state.
When the fuel tank 20 is full, the first ventilation port 56
Is closed, the second check valve 64
As a result, the pressure in the fuel tank 20 is set to the first set pressure P1.
If the second set pressure P2 higher than the above is exceeded, the canister 22
Allowed to leak to the side. That is, the pressure in the fuel tank 20 is set to the first set pressure P by the second check valve 64.
It will be managed below the second set pressure P2 higher than 1.

As a result, a space remains in the vicinity of the ceiling surface 58 of the fuel tank 20, and the fuel reaches the position L3 in the vicinity of the fuel filler port 30 in the fuel filler passage 28 to prevent fuel supply.

Thus, the fuel tank device 18 is
Since the first check valve 62 and the second check valve 64 can control the pressure in the fuel tank 20 to the first set pressure P1 or less and the second set pressure P2 or less,
By setting the first set pressure P1 lower than the conventional predetermined pressure, the pressure in the fuel tank 20 can be controlled to be lower than the first set pressure P1 lower than the conventional pressure. Therefore, the pressure in the fuel tank 20 can be controlled to be lower than the lower first set pressure, and it is possible to comply with recent regulations.

When the fuel tank 20 is filled with fuel, when the fuel tank 20 is full, the pressure in the fuel tank 20 is controlled to be equal to or lower than the second set pressure P2 which is higher than the first set pressure P1. Similarly, the pressure can be controlled to a high second set pressure or less. Therefore, overfilling of fuel can be prevented.

Further, since the fuel tank device 18 has a simple structure, it can operate reliably, has high reliability, and can be implemented at low cost, which is practically advantageous.

FIG. 4 shows a second embodiment of the present invention. In addition, in the second embodiment, the ventilation passage 1 on the downstream side of the canister 122 of the fuel tank device 118 is provided.
Since the configuration of 46 is the same as that of the first embodiment, only the main part will be described as an example.

In FIG. 4, the fuel tank device 118 is
Fuel tank 120 for storing fuel for an internal combustion engine (not shown)
A canister 122 for adsorbing and holding the vaporized fuel in the fuel tank 120 and for releasing and releasing the adsorbed and retained vaporized fuel for supplying to the internal combustion engine is provided.

Further, the fuel tank device 118 is constructed so that when the fuel tank 120 is in an unfilled state,
When the pressure in the fuel tank 120 exceeds the first set pressure P1 in order to control the pressure in 0 to be equal to or lower than the first set pressure P1,
Allowing outflow to the canister 122 side, and when the fuel tank 120 is full,
The second set pressure P higher than the first set pressure P1
In order to control the pressure to be 2 or less, a pressure management means 124 is provided that allows outflow to the canister 122 side when the pressure in the fuel tank 120 exceeds the second set pressure P2.

More specifically, the fuel tank 120 of the fuel tank device 118 is provided with an oil supply passage 128 which communicates with the communication port 126 on one end side. The other end of the oil supply passage 128 is inclined upward, and an oil supply port 130 is provided at the tip of the oil supply passage 128, and an oil supply cap 132 is detachably attached to the oil supply port 130. Further, the breather passage 136 communicating with the fuel tank 120 through the breather inlet 134 on one end side.
Is provided. The other end of the breather passage 136 is inclined upward, and the upper end 138 is bent and inclined downward, and the downwardly inclined breather outlet 140 at the tip is inclined.
Is communicated with the vicinity of the oil supply port 130 of the oil supply passage 128.

The canister 122 contains an adsorbent 142 such as activated carbon and temporarily adsorbs and holds the vaporized fuel generated in the fuel tank 120 and the like, and releases the adsorbed and retained vaporized fuel during operation of the internal combustion engine. And supply it to the internal combustion engine.

The pressure managing means 124 is provided with a ventilation passage 146 which communicates with one end side in an intake passage of an internal combustion engine (not shown), and the other end side of the ventilation passage 146 is connected to the first branch ventilation passage 150 at a branch point 148. It is provided by branching to the two-branch ventilation path 152. In the air passage 146 extending from the branch point 148 to the intake passage, the separator 1 is sequentially arranged from the branch point 148 side.
54 and the canister 122.
The canister 122 is provided with an atmosphere port 122A.

The first branch ventilation passage 150 is provided with a first ventilation port 156 on the other end side opening to the upper end 138 of the breather passage 136. The second branch ventilation passage 152 has the second ventilation port 160 on the other end side of the ceiling surface 15 of the fuel tank 120.
8 is opened.

The first check valve 162 is opened in the first branch air passage 150 when the pressure in the fuel tank 120 exceeds a first set pressure P1 (for example, 253 mmAq or lower which is lower than a predetermined pressure of the related art). Is installed. In addition, in the second branch air passage 152, a second set pressure P2 (for example, a conventional predetermined pressure 25) in which the pressure in the fuel tank 120 is higher than the first set pressure P1 is set.
A second check valve 164 that is opened when the pressure exceeds 3 mmAq) is provided. The first and second check valves 162 and 164 are two-way valves.

Therefore, the first set pressure P1 for opening the first check valve 162 and the second check valve 1 are set.
The second set pressure P2 for opening operation of 64 is P1 <P2
Is set to. That is, the second set pressure P2 at which the second check valve 64 opens is set higher than the first set pressure P1 at which the first check valve 62 opens.

As a result, when the fuel tank 120 is in an unfilled state, the pressure managing means 124 causes the pressure inside the fuel tank 120 to be less than or equal to the first set pressure P1 via the breather passage 136 by the first check valve 162. When the pressure in the fuel tank 120 exceeds the first set pressure P1, the flow to the canister 122 side is allowed, and when the fuel tank 120 is full, the second check valve 164 causes the fuel to flow. When the pressure in the fuel tank 120 exceeds the second set pressure P2 in order to manage the pressure in the tank 120 to be equal to or lower than the second set pressure P2 which is higher than the first set pressure P1, the outflow to the canister 122 side is allowed. ..

Next, the operation will be described. The fuel tank device 118 adjusts the pressure in the fuel tank 120 to the first check valve 1 when the fuel tank 120 is in an unfilled state.
62 controls the pressure to be equal to or lower than the first set pressure P1. As a result, the pressure in the fuel tank 120 is the first set pressure P.
When it exceeds 1, the outflow to the canister 122 side is allowed, and therefore the evaporated fuel flowing out from the fuel tank 120 can be adsorbed and held in the canister 122 via the breather passage 136.

Fuel tank 1 with reduced amount of stored fuel
When refueling the fuel tank 20, the refueling port 130 of the refueling passage 128
The refueling cap 132 attached to is removed and the refueling tool 172 is inserted into the refueling port 130. As a result, the oil supply port 130 of the oil supply passage 128 is blocked by the oil supply tool 172.

The fuel supplied by the refueling tool 172 is supplied from the refueling passage 128 through the communication port 126 to the fuel tank 120.
Flows in. As a result, the pressure in the fuel tank 120 increases due to the inflowing fuel. At this time, the pressure in the fuel tank 120 is adjusted by the first check valve 162 when the fuel tank 120 is in an unfilled state.
When the pressure in 20 exceeds the first set pressure P1, the outflow to the canister 122 side is allowed. That is, the pressure in the fuel tank 120 is controlled to be equal to or lower than the first set pressure P1 via the breather passage 136 by the first check valve 162.

Therefore, the excess air due to the increase in the pressure in the fuel tank 120 due to the inflowing fuel reaches the fuel filler port 130 via the fuel filler passage 128 and the breather passage 136. At this time, if the pressure in the fuel tank 120 exceeds the first set pressure P1, the first check valve 1
62 through the breather passage 136 to the canister 12
Since the outflow to the second side is allowed, the evaporated fuel flowing out from the fuel tank 120 can be adsorbed and held in the canister 122 via the breather passage 136.

At the time of refueling the fuel tank 120, the amount of fuel stored in the fuel tank 120 increases and the breather passage 13
When the height position of the breather inlet 134 of No. 6 is reached, the breather inlet 134 is closed to be in a full state. Fuel tank 1
When the pressure in the fuel tank 120 exceeds the second set pressure P2 higher than the first set pressure P1 by the second check valve 164 because the breather inlet 134 is closed in the full state of 20, the canister is closed. 122
Allowed to leak to the side. That is, the pressure in the fuel tank 120 is controlled by the second check valve 164 to be equal to or lower than the second set pressure P2 higher than the first set pressure P1.

Therefore, the ceiling surface 15 of the fuel tank 120 is
A space remains in the vicinity of 8, and the fuel reaches the vicinity of the fuel supply port 130 in the fuel supply passage 128 and the fuel supply is blocked.

As described above, in the fuel tank device 118 of the second embodiment, the pressure inside the fuel tank 120 is set to the first set pressure P1 or less and the second set pressure by the first check valve 162 and the second check valve 164. Since it can be controlled to P2 or less, as in the first embodiment, by setting the first set pressure P1 lower than the predetermined pressure in the related art, the pressure in the fuel tank 120 becomes lower than that in the related art. Since the pressure can be controlled to the set pressure P1 or lower, the pressure in the fuel tank 120 can be controlled to the lower first set pressure or lower, and it is possible to comply with recent regulations.

Further, when the fuel tank 120 is filled with fuel, when the fuel tank 120 is in a full state, the pressure in the fuel tank 120 is controlled to be equal to or lower than the second set pressure P2 which is higher than the first set pressure P1. Similarly, the pressure can be controlled to a high second set pressure or less. Therefore, overfilling of fuel can be prevented. Further, the fuel tank device 118 is
Since the structure is simple, the operation is reliable, the reliability is high, and the cost is low, which is practically advantageous.

FIG. 5 shows a third embodiment of the present invention. In addition, in the third embodiment, the air passage 2 on the downstream side of the canister 222 of the fuel tank device 218.
Since the configuration of 46 is the same as that of the first embodiment, only the main part will be described as an example.

In FIG. 5, the fuel tank device 218 is
Fuel tank 220 for storing fuel for an internal combustion engine (not shown)
And a canister 222 for adsorbing and holding the evaporated fuel in the fuel tank 220 and for releasing the adsorbed and held evaporated fuel to supply it to the internal combustion engine.

Further, the fuel tank device 218 is constructed so that when the fuel tank 220 is in an unfilled state, the fuel tank 22
When the pressure in the fuel tank 220 exceeds the first set pressure P1 in order to control the pressure in 0 to be equal to or lower than the first set pressure P1,
Allowing outflow to the canister 222 side, and when the fuel tank 220 is full,
The second set pressure P higher than the first set pressure P1
In order to control the pressure to 2 or less, a pressure control means 224 is provided to allow outflow to the canister 222 side when the pressure in the fuel tank 220 exceeds the second set pressure P2.

More specifically, the fuel tank 220 of the fuel tank device 218 is provided with an oil supply passage 228 that communicates with the communication port 226 on one end side. The other end of the oil supply passage 228 is inclined upwardly to provide an oil supply port 230 at the tip, and an oil supply cap 232 is detachably attached to the oil supply port 230. Further, the breather passage 236 communicating with the fuel tank 220 through the breather inlet 234 on one end side.
Is provided. The breather passage 236 is inclined upward at the other end and is bent at the upper end 238 to be inclined downward, and the breather outlet 240 at the tip which is inclined downward.
Is provided in communication with the vicinity of the oil supply port 230 of the oil supply passage 228.

The canister 222 contains an adsorbent 242 such as activated carbon and temporarily adsorbs and holds the vaporized fuel generated in the fuel tank 220 and the like, and releases the adsorbed and retained vaporized fuel during operation of the internal combustion engine. And supply it to the internal combustion engine.

The pressure managing means 224 is provided with a ventilation passage 246 which communicates with one end side in an intake passage of an internal combustion engine, and a ventilation port 256 on the other end side of the ventilation passage 246 is opened at an upper end 238 of the breather passage 236. Is provided. A check valve 262, a separator 254, and the canister 222 are sequentially provided from the vent hole 256 side in a vent passage 246 extending from the vent hole 256 to the intake passage.

The check valve 262 is a two-way valve, and the pressure in the fuel tank 220 is the first set pressure P1.
It is set to open when the pressure exceeds (for example, 253 mmAq or lower, which is lower than the conventional predetermined pressure).
The canister 222 is provided with an atmosphere port 222A.

Further, the fuel tank 320 and the oil supply passage 3
An auxiliary breather passage 266 is provided to communicate with 28. The auxiliary breather passage 266 is provided by opening the auxiliary breather inlet 274 on the one end side at a position lowered by a predetermined length L1 from the ceiling surface 258 of the fuel tank 220, and the auxiliary breather outlet 276 on the other end side is provided with the oil supply passage 328.
It is located slightly above the breather outlet 240 and opened. On the auxiliary breather inlet 274 side of the auxiliary breather passage 266, an orifice 278 is provided at a position close to the ceiling surface 158 slightly above the breather inlet 234.

The check valve 262 is set to open when the pressure in the fuel tank 220 exceeds a first set pressure P1 (for example, 253 mmAq or lower, which is lower than a predetermined pressure of the related art). Further, the orifice plate 278 has a second set pressure P2 (for example, a conventional set pressure P2) higher than the first set pressure P1 in the fuel tank 120 when the auxiliary breather inlet 274 and the breather inlet 234 are closed by the fuel. 25 which is a predetermined pressure
3 mmAq or more), the pressure is increased to 330
To act on.

Therefore, the first set pressure P1 for opening the check valve 262 and the second set pressure P1 acting on the orifice 278 in the state where the auxiliary breather inlet 274 and the breather inlet 234 are closed are higher than the first set pressure P1. P2 is set to P1 <P2.
That is, the orifice 278 is closed when the auxiliary breather inlet 274 and the breather inlet 234 are closed below the first set pressure P1 at which the check valve 262 opens.
The second set pressure P2 that acts on is set high.

As a result, when the fuel tank 220 is in an unfilled state, the pressure control means 224 causes the check valve 262 to pass the fuel tank 2 through the breather passage 236.
When the pressure in the fuel tank 220 exceeds the first set pressure P1, the outflow to the canister 222 is allowed and the fuel tank 220 is in a full state in order to manage the pressure in 20 below the first set pressure P1. In this case, the orifice 278 that functions when the auxiliary breather inlet 274 and the breather inlet 234 are closed causes the pressure in the fuel tank 120 to rise to the second set pressure P2 higher than the first set pressure P1.
In order to manage the pressure below, when the pressure in the fuel tank 220 exceeds the second set pressure P2, the outflow to the canister 222 side through the auxiliary breather passage 266 is permitted.

Next, the operation will be described. The fuel tank device 218 checks the pressure inside the fuel tank 220 when the fuel tank 220 is in an unfilled state.
Therefore, the first set pressure P1 is controlled below. As a result, when the pressure in the fuel tank 220 exceeds the first set pressure P1, it is allowed to flow out to the canister 222 side, so the evaporated fuel flowing out from the fuel tank 220 is adsorbed to the canister 222 via the breather passage 236. Can be held.

Fuel tank 2 in which the amount of stored fuel is reduced
When refueling No. 20, the refueling port 230 of the refueling passage 228
The refueling cap 232 attached to is removed and the refueling tool 272 is inserted into the refueling port 230. As a result, the oil supply port 230 of the oil supply passage 228 is blocked by the oil supply tool 272.

The fuel supplied by the refueling tool 272 is supplied from the refueling passage 228 through the communication port 226 to the fuel tank 220.
Flows in. As a result, the pressure in the fuel tank 220 increases due to the inflowing fuel. At this time, the pressure in the fuel tank 220 is adjusted by the check valve 262 when the fuel tank 220 is in an unfilled state.
When the internal pressure exceeds the first set pressure P1, the canister 2
22 is allowed to flow out. That is, the fuel tank 22
The pressure within 0 is controlled by the check valve 262 via the breather passage 236 to be equal to or lower than the first set pressure P1.

Therefore, the excess air due to the increase in the pressure in the fuel tank 220 due to the inflowing fuel reaches the fuel filler port 230 via the fuel filler passage 228 and the breather passage 236. At this time, if the pressure in the fuel tank 220 exceeds the first set pressure P1, the check valve 262
This allows the outflow to the canister 222 side via the breather passage 236, so that the evaporated fuel flowing out from the fuel tank 220 is passed through the breather passage 236 to the canister 2
It can be adsorbed and held by 22. At this time,
Orifice 278 is not functioning.

When the fuel tank 220 is refueled, the amount of fuel stored in the fuel tank 220 increases, and the auxiliary breather inlet 274 and the breather passage 23 of the auxiliary breather passage 276 are increased.
When the height position of the breather inlet 234 of No. 6 is reached, the auxiliary breather inlet 274 and the breather inlet 234 are closed to be in a full state. In the full state of the fuel tank 220, the auxiliary breather inlet 274 and the breather inlet 234 are closed, so that the orifice 278 in the fuel tank 220 is operated by the orifice 278 that functions when the auxiliary breather inlet 274 and the breather inlet 234 are closed. When the pressure exceeds the second set pressure P2 which is higher than the first set pressure P1, the canister 2 passes through the auxiliary breather passage 266.
22 is allowed to flow out. That is, the fuel tank 22
The pressure within 0 is the first set pressure P due to the orifice 278.
It will be managed below the second set pressure P2 higher than 1.

Therefore, the ceiling surface 25 of the fuel tank 220 is
A space remains in the vicinity of 8, and the fuel reaches the vicinity of the fuel supply port 230 in the fuel supply passage 228, and the fuel supply is blocked.

As described above, the fuel tank device 218 of the third embodiment has the check valve 262 and the orifice 27.
8 to set the pressure in the fuel tank 220 to the first set pressure P
Since it can be controlled to 1 or less and the second set pressure P2 or less, the first set pressure P1 can be set as in the first and second embodiments.
Is set to be lower than a predetermined pressure of the related art, so that the pressure in the fuel tank 220 is set to a first set pressure P lower than that of the related art.
Since it can be controlled to 1 or less, the pressure in the fuel tank 220 can be controlled to a lower first set pressure or less, and it is possible to comply with recent regulations.

When the fuel tank 220 is filled with fuel, when the fuel tank 220 is full, the pressure in the fuel tank 220 is controlled to be equal to or lower than the second set pressure P2 which is higher than the first set pressure P1. Similarly, the pressure can be controlled to a high second set pressure or less. Therefore, overfilling of fuel can be prevented. Further, the fuel tank device 218 is
Since the structure is simple, the operation is reliable, the reliability is high, and the cost is low, which is practically advantageous.

[0070]

As described above, according to the present invention, the fuel tank device can control the pressure in the fuel tank to be equal to or lower than the first set pressure and equal to or lower than the second set pressure.
By setting the set pressure lower than the conventional pressure, the pressure in the fuel tank can be controlled to be lower than the first set pressure lower than the conventional pressure. Therefore, the pressure in the fuel tank can be controlled to be lower than the lower first set pressure, and it is possible to comply with recent regulations. Also, when refueling the fuel tank,
In the case of the full state, by controlling the pressure in the fuel tank to be equal to or lower than the second set pressure higher than the first set pressure,
As in the conventional case, the second set pressure can be controlled to be high below. Therefore, overfilling of fuel can be prevented. Further, since this fuel tank device has a simple structure, it can be operated reliably, has high reliability, and can be implemented at low cost, which is practically advantageous.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a fuel tank device showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of a fuel tank device in an unfilled state.

FIG. 3 is a configuration diagram of a main part of the fuel tank device in a full state.

FIG. 4 is a main part configuration diagram of a fuel tank device showing a second embodiment of the present invention.

FIG. 5 is a main part configuration diagram of a fuel tank device showing a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a main part of a fuel tank device showing a conventional example.

[Explanation of symbols]

 2 Internal Combustion Engine 4 Air Cleaner 8 Surge Tank 10 Intake Passage 14 Exhaust Passage 16 Fuel Injection Valve 18 Fuel Tank Device 20 Fuel Tank 22 Canister 24 Pressure Management Means 28 Refueling Passage 36 Breather Passage 46 Air Vent 50 First Branch Vent 52 Second Branch Ventilation passage 54 Separator 62 First check valve 64 Second check valve 66 Auxiliary breather passage 68 Open / close valve 70 Control unit

Claims (1)

[Claims] 1. A fuel tank for storing fuel of an internal combustion engine is provided, and a canister is provided for adsorbing and holding the vaporized fuel in the fuel tank, and for releasing and releasing the adsorbed and retained vaporized fuel to supply to the internal combustion engine. When the fuel tank is in an unfilled state, the pressure in the fuel tank is set to the first set pressure in order to control the pressure in the fuel tank to be the first set pressure or less.
When the set pressure is exceeded, the flow to the canister side is allowed, and when the fuel tank is full, the pressure in the fuel tank is controlled to be equal to or lower than the second set pressure higher than the first set pressure. A fuel tank device comprising a pressure management means for permitting outflow to the canister side when the pressure in the fuel tank exceeds the second set pressure.