JPH0968113A - Canister structure of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lowering of performance of a canister through effective return of liquid fuel to a fuel tank even when the liquid fuel flows to the vicinity of an evaporation flow passage by a method wherein a control valve for a pressure in a tank released on a specified condition is located in each deformed evaporation passage to intercommunicate the fuel tank and the canister. SOLUTION: Three evaporation passages 42, 44, and 46 to intercommunicate a fuel tank 16 and a canister 50 are installed, and the first evaporation passage 42 is formed in a relatively large diameter. First - third tank internal pressure control valves 56, 72, and 80 released, in order, when an internal pressure in the fuel tank 16 attains first or third set pressure during the feed of oil to the fuel tank 16 during the stop of an internal combustion engine 2 are disposed in the evaporation passages 42, 44, and 46. Further, a canister 50 is horizontally arranged, and when liquid fuel flows in the canister 50 from the first evaporation passage 42, the liquid fuel is dropped in a partition space 122 and resides in a liquid reservoir 124, and when the fuel tank 16 is cooled and brought into a negative pressure, the liquid fuel is returned to the fuel tank 16 side again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a canister structure for an internal combustion engine, and more particularly to a canister structure for an internal combustion engine capable of preventing performance deterioration of the canister.

[0002]

2. Description of the Related Art In a vehicle, evaporated fuel leaking into the atmosphere from a fuel tank or the like contains a large amount of hydrocarbons (HC) and is one of the causes of air pollution, and also leads to fuel loss. For this reason, various techniques for preventing this are known. As a typical example, there is an evaporative fuel control device (evaporation system) in which evaporative fuel in a fuel tank is separated (purged) from a canister containing an adsorbent such as activated carbon during operation of the internal combustion engine and supplied to the internal combustion engine.

The structure of the canister is disclosed, for example, in Japanese Utility Model Laid-Open No. 5-77569. The one disclosed in this publication has a right-angled partition parallel to the long axis of a horizontally long container and a horizontal partition provided on one of the chambers divided by the vertical partition to form a first chamber, a second chamber, and It is divided into a third chamber above the second chamber, and an upper air chamber, a middle activated carbon chamber, and a lower air chamber are provided in each of the first chamber and the second chamber to allow gas flow, and the third chamber has a vertical barrier. Is provided to form a U-shaped passage, an introduction pipe and a discharge pipe are provided in the upper air chamber of the first chamber, the lower air chambers are communicated with each other, and the middle activated carbon chamber and the third chamber of the second chamber are filled with activated carbon. It is a composition.

[0004]

By the way, in the fuel vapor control system, the canister may have to be mounted horizontally on the vehicle due to the layout. In this case, if liquid fuel flows into the canister from the fuel tank, the liquid fuel adversely affects the activated carbon of the canister, resulting in deterioration of the performance of the canister, resulting in inferior durability.

[0005]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention adsorbs and holds the vaporized fuel that is generated in the fuel tank and is guided to the evaporation passage while the internal combustion engine is stopped. In a canister structure of an internal combustion engine in which evaporated fuel adsorbed and held by the introduced atmosphere is separated and supplied from a purge passage to an intake passage during operation of the internal combustion engine, the first and the first communicating the fuel tank and the canister. 2, a third evaporation passage is provided, the diameter of the first evaporation passage is formed larger than the diameters of the second and third evaporation passages, and the fuel tank is refueled while the internal combustion engine is stopped. A first tank internal pressure control valve that opens so as to open the first evaporation passage when the tank internal pressure of the fuel tank reaches a first set pressure is provided to the fuel tank when the internal combustion engine is stopped. A second tank internal pressure control valve that opens so as to open the second evaporation passage when the tank internal pressure of the fuel tank reaches a second set pressure before refueling and during operation of the internal combustion engine is provided. When the internal pressure of the fuel tank reaches a third set pressure higher than the second set pressure after the fuel tank is refueled at
A third tank internal pressure control valve that opens so as to open the evaporation passage is provided, the canister is installed horizontally, and the first evaporation passage is located at a lower position where the second and third evaporation passages communicate with each other. Is also provided so as to communicate with the lateral side of the canister at a high position.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, when a canister is installed horizontally on a vehicle, even if the liquid fuel flows into the canister from the large-diameter first evaporation passage, the liquid fuel will flow downward. It falls to the vicinity of the second and third evaporation passages, and when the inside of the fuel tank becomes negative pressure, it is returned from the second and third evaporation passages to the fuel tank.
As a result, the liquid fuel does not adversely affect the activated carbon of the canister, preventing the performance of the canister from decreasing,
The durability of the canister can be improved.

[0007]

Embodiments of the present invention will be described in detail and specifically with reference to the drawings. 1 to 10 show an embodiment of the present invention. In FIG. 1, 2 is an internal combustion engine mounted on a vehicle (not shown), 4 is an intake manifold, 6 is an intake passage, 8 is a surge tank, 10 is a throttle valve, 12 is a fuel injection valve, 14 is an air cleaner, 16 Is a fuel tank. An oil supply pipe (filler hose) 20 provided with an oil supply cap 18 is connected to the fuel tank 16. The oil supply pipe 20 forms an oil supply passage (filler passage) 22.

The refueling cap 18 is provided with a refueling side check valve 24.

A fuel pump 26 is provided in the fuel tank 16.
A first float valve 28 and a second float valve 30 that move up and down according to the amount of fuel, and a level gauge 32 that detects the amount of fuel are provided. One end of a fuel supply passage 34 is connected to the fuel pump 26. The other end of the fuel supply passage 34 is provided so as to communicate with the fuel injection valve 12. A fuel pressure regulator 36 is connected to the fuel injection valve 12. One end side of a fuel return passage 38 is provided in communication with the fuel pressure regulator 36. The other end of the fuel return passage 38 is provided so as to open in the fuel tank 16.

An evaporated fuel control device (evaporation system) 40 is provided between the fuel tank 16 and the intake system of the internal combustion engine 2.

In this evaporated fuel control device 40, the other end side of each of the first to third evaporation passages 42 to 46, one end side of which communicates with the inside of the fuel tank 16, and the other end side thereof are connected to the surge tank 8 constituting the intake passage 6. A canister 50 is provided between the other end of the communicating purge passage 48.

In the first float guide body 52, one end side of the first evaporation passage 42 is opened and closed by the first float valve 28 which is guided in the first float guide body 52 in the fuel tank 16 and moves up and down. It is installed in. Second
One end of the evaporation passage 44 communicates with the first evaporation passage 42, as shown in FIG.

Inside the second float guide body 54, one end side of the third evaporation passage 46 is opened and closed by the second float valve 30 which is guided in the second float guide body 54 in the fuel tank 16 and moves up and down. It is installed in. Second
The other end side of the evaporation passage 44 communicates with the middle of the third evaporation passage 46.

The first evaporation passage 42 is, as shown in FIG.
It has a predetermined first diameter D1. As shown in FIG. 6, the second evaporation passage 44 is formed in the first evaporation passage 42 of the first evaporation passage 42.
The second diameter D2 is smaller than the diameter D1. Third
The evaporation passage 46 is, as shown in FIG. 7, the first evaporation passage 4
2 smaller than the first diameter D of the second evaporative passage 44
The third diameter D3 is substantially the same as the diameter D2.

In the first evaporation passage 42, when the tank internal pressure of the fuel tank 16 reaches a predetermined first set pressure during refueling of the fuel tank 16 when the internal combustion engine 2 is stopped, the first evaporation passage 42 is opened. A first tank internal pressure control valve 56 that opens so as to open is provided.

The first tank internal pressure control valve 56 is shown in FIG.
As shown in FIG. 6, the pressure action chamber 6 defined by the diaphragm 60, which is the first partition, in the first housing 58.
2 and a passage communication chamber 64 are provided, and the pressure action chamber 6
2, a spring 66 for pressing the diaphragm 60 is provided, and further, a valve seat body 68 for opening and closing the first evaporation passage 42 by contacting and separating the central portion of the diaphragm 60 in the passage communication chamber 64 is provided. Pressure action chamber 62
The fuel supply passage 22 and the oil supply passage 22 are connected by a tank-side communication passage 70. One end of the second evaporation passage 44 is communicated with the first evaporation passage 42 on the first float valve 28 side of the first tank internal pressure control valve 56.

In the second evaporation passage 44, the tank internal pressure of the fuel tank 16 is a predetermined second set pressure (for example, 10 when the internal combustion engine 2 is stopped, before refueling the fuel tank 16 and while the internal combustion engine 2 is in operation). A second tank internal pressure control valve 72 is provided which operates to open so as to open the second evaporation passage 44 when it reaches inch (Hg). This second tank internal pressure control valve 7
As shown in FIG. 6, 2 is a check valve, and has a second partition body 76 in the second housing 74 and second check bodies 78-1 and 78-2 provided in the second partition body 76. are doing. The above-mentioned second set pressure is a pressure value with which the second tank internal pressure control valve 72 can be easily opened even while the vehicle is traveling.

In the third evaporation passage 46, when the internal pressure of the fuel tank 16 reaches a predetermined third set pressure higher than the above-mentioned second set pressure after refueling the fuel tank 16 when the internal combustion engine 2 is stopped. A third tank internal pressure control valve 80 that opens so as to open the third evaporation passage 46 is provided.
As shown in FIG. 7, the third tank internal pressure control valve 80 is a check valve, and includes a third partition body 84 in the third housing 82 and a third check body 86-1 provided in the third partition body 84. , 86-2. Second evaporation passage 4
The other end side of No. 4 is connected to the third evaporation passage 46 on the canister 50 side of the third tank internal pressure control valve 80. Further, the above-mentioned third set pressure is a pressure value that causes the third tank internal pressure control valve 80 to close even during refueling of the fuel tank 16.

Further, in the first evaporation passage 42, which is closer to the first float valve 28 than the first tank internal pressure control valve 56, and is closer to the first float valve 28 than where the one end side of the second evaporation passage 44 is communicated. The one end side of the relief passage 88 communicates with the relief passage 88. The other end of the relief passage 88 communicates with the oil supply passage 22.

A relief valve 90, which is a check valve that opens when the pressure in the first evaporation passage 42 becomes abnormally high, is provided in the middle of the relief passage 88.

In the third evaporation passage 44, the detection pressure passage 9 is provided between the second float valve 30 and the third tank internal pressure control valve 80.
A pressure sensor 94 for detecting the internal pressure of the fuel tank 16 is provided via the pressure sensor 94.

A purge valve (solenoid valve) 96 for controlling the amount of evaporated fuel to the intake passage 6 according to the operating state of the internal combustion engine 2 is provided in the middle of the purge passage 48.

As shown in FIG. 8, the purge passage 48 has a second
It is formed with a fourth diameter D4 which is substantially the same diameter as the evaporation passage 44. Further, the purge valve 96 is a two-way solenoid valve, and has a solenoid 100 inside the fourth housing 98.
And the valve body 1 that reciprocates so as to open and close the purge passage 48.
02.

The canister 50 adsorbs and holds the vaporized fuel generated in the fuel tank 16 and guided to the first to third evaporation passages 42 to 44, and while the internal combustion engine 2 is in operation, the main atmosphere communication passage 104. The vaporized fuel adsorbed and held by the atmosphere introduced from is separated and supplied from the purge passage 48 to the intake passage 6.

The main atmosphere communication passage 104 is branched into a first branch atmosphere communication passage 106 and a second branch atmosphere communication passage 108. The first branch atmosphere communication passage 106 is provided with a first air cut valve (solenoid valve) 110 that opens and closes the first branch atmosphere communication passage 106. The second branch atmosphere communication passage 108 includes the second branch atmosphere communication passage 10
Second air cut valve (solenoid valve) 112 for opening and closing 8
Is provided.

The canister 50 is installed horizontally on the vehicle, and has a vertical partition wall 116 vertically oriented at a substantially central portion in the canister housing 114.
The partition wall 118 is arranged so as to be substantially orthogonal to the vertical partition wall 116 and encloses activated carbon. Therefore, a partition space 120 is formed between the canister housing 114 and the partition grid 118.

The canister housing 114 is shown in FIGS.
As shown in FIG. 4, the large-diameter first evaporation passage 42 is provided laterally to the third side.
The purge passage 4 is communicated with the upper portion of the position higher than the evaporation passage 46, and is below the first evaporation passage 42.
8 communicates with each other, and further, the third evaporation passage 46 communicates with the bottom portion below the purge passage 48.

Further, in the canister housing 114, a partition wall 122 having a predetermined height rising from the bottom is provided in the vicinity of the communication of the third evaporation passage 46. A liquid retaining portion 124 is formed in the partition space 120 between the partition wall 122 and the canister housing 114.

The fuel injection valve 12, the level gauge 32, the pressure sensor 94, the purge valve 96, and the first and second air cut valves 1
10 and 112 communicate with the control means 126.

The control means 126 includes a level gauge 32.
And various signals from the pressure sensor 94 and the like are input to operate the fuel injection valve 12 while the internal combustion engine 2 is operating to operate the internal combustion engine 2
To control the amount of fuel supplied to the canister 50, and to open and close the first and second air cut valves 110 and 112 to open and close the first and second branch atmosphere communication passages 106 and 108 to introduce the atmosphere into the canister 50. Alternatively, the air from the canister 50 is released, and the purge valve 96 is opened and closed to operate the purge passage 4
8 is opened and closed to control the amount of evaporated fuel to the intake passage 6.

Next, the operation of this embodiment will be described.

Before the fuel tank 16 is refueled when the internal combustion engine 2 is stopped, the tank internal pressure of the fuel tank 16 becomes the second value.
When the set pressure (for example, 10 inches Ag) is reached, the second tank internal pressure control valve 72 opens to control the tank internal pressure. At this time, in the first tank internal pressure control valve 72, since the pressure acting chamber 62 and the passage communication chamber 64 have the same pressure, the diaphragm 60 is joined to the valve seat body 68 by the urging force of the spring 66, and the first evaporation is performed. The passage 42 is closed. Further, the third tank internal pressure control valve 80 is
Since the tank internal pressure of 6 has not reached the third set pressure higher than the second set pressure, the third evaporation passage 46 is closed.
As a result, the tank internal pressure of the fuel tank 16 is controlled by the second tank internal pressure control valve 72, the evaporated fuel generated in the fuel tank 16 is collected by the canister 50, and the air contained in the evaporated fuel is removed. Main atmosphere communication passage 104
Is discharged from the outside.

At the time of stopping the internal combustion engine 2, during the refueling of the fuel tank 16 by the refueling gun (not shown), the atmospheric pressure acts on the pressure working chamber 62 of the first tank internal pressure control valve 56, and When the tank internal pressure of the fuel tank 16 reaches the first set pressure, the diaphragm 60 overcomes the urging force of the spring 66 and is displaced, so that the first tank internal pressure control valve 56 opens and the first evaporation passage 42 opens. To do. At this time, the second and third tank internal pressure control valves 72 and 80 close the second and third evaporation passages 44 and 46. As a result, the evaporated fuel generated in the fuel tank 16 is collected by the canister 50 through the large-diameter first evaporation passage 42. The air contained in the evaporated fuel is discharged to the outside from the main atmosphere communication passage 104.

When the internal combustion engine 2 is stopped and the fuel tank 16 is refueled, the first and second float valves 28, 30 are
The second evaporation passages 42 and 44 are closed, but the fuel tank 1
When the tank internal pressure of 6 reaches the third set pressure, the third tank internal pressure control valve 80 is opened, and the third evaporation passage 46 is opened. As a result, the evaporated fuel generated in the fuel tank 16 is collected by the canister 50, and the air contained in the evaporated fuel is discharged from the main atmosphere communication passage 104 to the outside.

During operation of the internal combustion engine 2, the inside of the fuel tank 1
When the fuel amount of 6 decreases and the tank internal pressure decreases, the first,
The third tank internal pressure control valves 56 and 80 are closed, and the tank internal pressure of the fuel tank 16 is controlled by the opening operation of the second tank internal pressure control valve 72 when the tank internal pressure exceeds the second set value. The evaporated fuel generated in the fuel tank 16 flows out to the canister 50 side.

As a result, the evaporated fuel can be collected in the canister 50 before, during, and after refueling of the fuel tank 16 when the internal combustion engine 2 is stopped, so that air pollution can be prevented. it can.

Further, during operation of the internal combustion engine 2, only the second tank internal pressure control valve 72 is opened and only the second evaporation passage 44 having a small diameter is opened, so that the intake pipe negative pressure in the fuel tank 16 is reduced. Can be prevented from becoming negative pressure in the fuel tank 16, and the fuel in the fuel tank 16 can be prevented from flowing out to the canister 50 side.

Further, the evaporated fuel control device 40 of this embodiment
In the above, the normal evaporative control is properly performed during the operation of the internal combustion engine 2, and a regulation for preventing the evaporative fuel from being released to the atmosphere when the internal combustion engine 2 is stopped or while the fuel tank 16 is being refueled, Regulations for opening and closing the valves such as the purge valve 96 and the first and second air cut valves 110 and 112 to check the leakage of evaporated fuel can also be dealt with.

Furthermore, even if the canister 50 is installed horizontally and the liquid fuel flows into the canister 50 from the large-diameter first evaporation passage 42, the liquid fuel drops in the partition space 120. When the fuel tank 16 cools and the inside of the fuel tank 16 becomes negative pressure, the negative pressure causes the fuel tank 16 to be returned to the fuel tank 16 side again by so-called back purge (see FIG. 9). 10). As a result, the liquid fuel does not adversely affect the activated carbon of the canister 50, and thus the performance deterioration of the canister 50 is prevented, and thus the durability of the canister 50 is prevented, and thus the canister 50 is prevented.
Can be improved in durability.

A partition wall 122 is provided in the canister 50.
Since the liquid retaining portion 124 is formed by the above, the liquid fuel does not affect the activated carbon side, and the performance deterioration of the canister 50 can be more effectively prevented.

[0041]

As is apparent from the above detailed description, according to the present invention, the first, second, and third evaporation passages that connect the fuel tank and the canister are provided, and the diameter of the first evaporation passage is set to the second. The diameter of the third evaporation passage is larger than that of the third evaporation passage, and when the internal pressure of the fuel tank reaches the first set pressure during refueling of the fuel tank when the internal combustion engine is stopped, the first evaporation passage is opened. Providing an operating first tank internal pressure control valve,
When the internal combustion engine is stopped and before the fuel tank is refueled and while the internal combustion engine is operating, the second opening operation is performed to open the second evaporation passage when the tank internal pressure of the fuel tank reaches the second set pressure.
A tank internal pressure control valve is provided to open the third evaporation passage when the internal pressure of the fuel tank reaches a third set pressure higher than the second set pressure after the fuel tank is refueled when the internal combustion engine is stopped. The third tank internal pressure control valve is installed, the canister is installed horizontally, and the first evaporation passage is connected to the second and third tanks.
When the canister is installed horizontally, the liquid fuel is supplied from the first evaporation passage having a large diameter when the canister is installed horizontally because the communication is provided at a position higher than the position of the low portion where the evaporation passage communicates. Even if the liquid fuel flows into the canister, the liquid fuel drops downward to reach the vicinity of the second and third evaporation passages, and the negative pressure in the fuel tank causes the fuel to flow from the second and third evaporation passages. Since it is returned to the tank, it does not adversely affect the activated carbon of the canister,
It is possible to prevent the performance of the canister from decreasing and improve the durability of the canister.

[Brief description of drawings]

FIG. 1 is a system structure diagram of an evaporated fuel control device.

FIG. 2 is a main part configuration diagram of an evaporated fuel control device.

FIG. 3 is a plan view of a canister.

FIG. 4 is a side view of a canister.

FIG. 5 is a configuration diagram of a first tank internal pressure control valve.

FIG. 6 is a configuration diagram of a second tank internal pressure control valve.

FIG. 7 is a configuration diagram of a third tank internal pressure control valve.

FIG. 8 is a configuration diagram of a purge valve.

FIG. 9 is a configuration diagram showing a state in which liquid fuel has flown into a canister.

FIG. 10 is a configuration diagram showing a state where liquid fuel is returned to the fuel tank.

[Explanation of symbols]

 2 Internal Combustion Engine 16 Fuel Tank 22 Oil Supply Path 28 First Float Valve 30 Second Float Valve 40 Evaporative Fuel Control Device 42 First Evaporation Passage 44 Second Evaporation Passage 46 Third Evaporation Passage 48 Purge Passage 50 Canister 56 First Tank Internal Pressure Control Valve 72 Second tank internal pressure control valve 80 Third tank internal pressure control valve 96 Purge valve 116 Vertical partition wall 118 Partition grid 120 Partition space 122 Partition wall 124 Liquid retention part 126 Control means

Claims (2)

[Claims] 1. The adsorbed fuel is adsorbed and held by the introduced atmosphere while the internal combustion engine is stopped, and the evaporated fuel that is generated in the fuel tank and is guided to the evaporation passage is adsorbed and held. In a canister structure of an internal combustion engine in which the purge passage is supplied to the intake passage, first, second, and
A third evaporation passage is provided, the diameter of the first evaporation passage is formed larger than the diameters of the second and third evaporation passages, and the fuel tank is refueled while the internal combustion engine is stopped and fuel is being supplied to the fuel tank. When the tank internal pressure reaches the first set pressure, the first
A first tank internal pressure control valve that opens so as to open the evaporation passage is provided, and when the internal combustion engine is stopped, the tank internal pressure of the fuel tank is set to a first value before the fuel tank is refueled and during operation of the internal combustion engine. A second tank internal pressure control valve that opens so as to open the second evaporation passage when the second set pressure is reached is provided, and when the internal combustion engine is stopped, the tank internal pressure of the fuel tank is the above after the fuel tank is refueled. A third tank internal pressure control valve that opens so as to open the third evaporation passage when a third set pressure higher than the second set pressure is reached,
The canister is installed horizontally, and the first evaporation passage is provided laterally of the canister at a position higher than a position of a low portion where the second and third evaporation passages communicate with each other. Canister structure for internal combustion engine. 2. The laterally placed canister includes the second,
The canister structure for an internal combustion engine according to claim 1, further comprising a liquid retaining portion formed by a partition wall at a bottom portion communicating with the third evaporation passage.