JPH0741885Y2 - Canister - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a canister for trapping fuel vapor generated from a fuel system of an engine to prevent its release into the atmosphere, and more particularly to a canister for liquid fuel in a fuel storage chamber formed at the bottom of a case. It relates to a canister that separates and holds minutes.

[0002]

2. Description of the Related Art A canister captures a fuel vapor generated from a fuel tank or a carburetor with an adsorbent, while desorbing a fuel component from the adsorbent with the air taken in during engine operation.
The same fuel components are sent to the engine along with the atmosphere.

Conventionally, as this type of canister, the one disclosed in JP-A-62-265460 as shown in FIG. 4 is known. In the figure, a cylindrical case 1 has a fuel storage chamber 3 at the bottom, and an activated carbon 2 is filled at the top thereof. Further, on the center axis of the case 1, a double cylindrical fuel introduction pipe 4 and a fuel derivation pipe 5 are arranged so as to penetrate the two layers of the activated carbon, and the inside of the fuel storage chamber 3 in the fuel introduction pipe 4 is arranged. A fuel introducing hole 6 is provided in the portion that has entered, and a fuel vapor discharge hole 7 that communicates with the fuel introducing tube 4 is provided in the portion of the fuel outlet pipe 5 that has entered the fuel reservoir chamber 3 toward the upper side. There is also a liquid fuel discharge hole 8 formed near the lower side.

At the upper part of the case 1, an atmosphere introducing hole 9 communicating with the outside air is provided, and the fuel introducing pipe 4 is communicated with the upper space of the fuel tank by a pipe (not shown), and the fuel outlet pipe 5 is provided.
Is connected to the intake system. In such a configuration,
The fuel in the fuel tank becomes vapor and enters the fuel reservoir 3 from the fuel introduction pipe 4 through the fuel introduction hole 6. Then, this fuel vapor is adsorbed by the activated carbon 2, and only air is diffused into the atmosphere through the air introduction hole 9.

On the other hand, during operation of the engine, the atmosphere is sucked into the case 1 through the atmosphere introduction hole 9 by the action of the negative pressure from the engine, and the fuel vapor is desorbed when passing through the two layers of activated carbon. Then, the atmosphere is accompanied by the fuel vapor and the fuel vapor discharge hole 7
To the fuel outlet pipe 5 to the intake system of the engine. Liquid fuel is also drawn from the fuel tank into the fuel storage chamber 3 and stored at the bottom, and when a negative pressure from the engine acts, this liquid content is drawn into the fuel outlet pipe 5 from the liquid fuel discharge hole 8. Is sucked into the intake system along with the steam.

[0006]

In the above-described conventional canister, it is difficult to control the amount of the liquid component of the fuel accumulated in the fuel reservoir chamber, which is sucked by the negative pressure from the engine. For example, even if it is desired to keep the ratio of the atmosphere and the fuel vapor sucked through the fuel outlet pipe within a predetermined range, if a certain amount of liquid is stored in the fuel storage chamber, the liquid will be sucked as it is. However, the concentration of fuel vapor becomes too high, which causes problems in fuel control.

In particular, if a large amount of liquid is accumulated in the fuel reservoir such that both the fuel vapor discharge hole 7 and the liquid fuel discharge hole 8 are blocked, only the liquid fuel is immediately sucked from the fuel outlet pipe 5. Towards the engine, the concentration of fuel vapor becomes too high. The present invention has been made in view of the above problems, and an object of the present invention is to provide a canister capable of easily controlling the intake rate of fuel vapor.

[0008]

In order to achieve the above object, the invention according to claim 1 forms a fuel storage chamber at the bottom of the case, and communicates with the fuel storage chamber at the lower part and at the upper part. An adsorbent layer of fuel vapor communicating with the outside air is arranged in the case, and a first series passage for connecting the fuel storage system of the engine to the fuel storage chamber and an intake system of the engine are connected to the fuel storage chamber. In a canister having a second communication passage, the second communication passage is a purge chamber facing a part of the lower surface of the adsorbent layer separately from the fuel storage chamber below the adsorbent layer. And a first fuel derivation path having a liquid fuel suction port that opens at the bottom of the fuel storage chamber at the bottom and a small-diameter nozzle opening in the purge chamber at the top, and penetrates the adsorbent layer vertically. Do with From the purge chamber to the nozzle opening top of the first fuel outlet path a configuration equipped with a second fuel outlet passage that forms a suction passage to the intake system of the engine.

[0009]

In the invention according to claim 1 configured as described above, the fuel vapor generated from the fuel storage system enters the fuel storage chamber through the first series passage, passes through the adsorbent layer, and then exits the case. By the time it comes out, it is adsorbed by the adsorbent layer. Further, the liquid component is stored in the fuel storage chamber. On the other hand, during engine operation, negative pressure acts on the lower surface side of the adsorbent layer through the second communication passage that vertically penetrates the adsorbent layer, and the outside air is sucked from the surface of the adsorbent layer. When the outside air passes through the adsorbent layer, it desorbs the fuel vapor adsorbed in the adsorbent layer and enters the purge chamber. Then, the outside air containing the fuel vapor is sucked into the intake system of the engine from the purge chamber via the second fuel outlet path.

When the outside air passes through the suction flow passage sucked from the purge chamber to the second fuel discharge passage, a negative pressure is generated in the nozzle opening portion of the first fuel discharge passage facing the suction flow passage. Since the lower end of the first fuel outlet passage is open at the bottom of the fuel storage chamber, when the liquid portion of the fuel is stored in the fuel storage chamber, it is sucked up to the nozzle opening portion according to the negative pressure. Then, it is blown out from the nozzle opening into the second fuel outlet path like a mist, and is sucked into the intake system of the engine. At this time, the blowing amount can be set to a desired amount according to the opening diameter of the nozzle, the form of the suction path, and the like.

[0011]

As described above, the present invention can provide a canister having the following effects. Since the liquid component of the fuel is sucked in in the manner of spraying, the fuel is not rapidly supplied to the intake system, and the fuel control is easy to perform. Further, the suction amount can also be adjusted by changing the nozzle opening and the suction path, which does not adversely affect the fuel control. For example, since the original fuel consumption is low at low speed rotation, the liquid content is prevented from being supplied as much as possible to prevent fluctuations in the supply volume, and the liquid content is reduced when the original fuel consumption is large as at high speed rotation. If it is supplied in the form of a mist, it is possible to perform good fuel control.

Negative pressure acts on the second communication passage during engine operation, and the second communication passage communicates with the fuel storage chamber via the first fuel outlet passage having a small diameter nozzle opening. Therefore, the suction force due to the negative pressure acts on the lower surface of the adsorbent layer in the purge chamber where the second fuel outlet passage opens, and sucks the outside air. Here, since the lower surface region of the adsorbent layer communicating with the purge chamber and the lower surface region of the adsorbent layer communicating with the fuel reservoir chamber are different portions, the fuel reservoir chamber enters through the first series passage. The incoming fuel vapor enters the adsorbent layer from the lower surface region of the adsorbent layer facing the fuel reservoir chamber, and enters the purge chamber from the lower surface region of the adsorbent layer facing the purge chamber. That is, once the adsorbent layer has not been passed, it will not enter the purge chamber. Therefore, what is supplied to the intake system is the fuel vapor that has been desorbed from the adsorbent by the external air, and can be supplied in a state in which it is easily combusted.

A fuel storage chamber is formed at the bottom of the case, and a first fuel lead-out passage that enters the fuel storage chamber is provided. The upper end of the first fuel lead-out passage is inserted into the purge chamber, and the purge chamber is A second fuel derivation path that is in communication with the adsorbent layer and that is vertically oriented is connected. Therefore,
Since it will be assembled almost vertically, it can be easily assembled in the case.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a canister according to an embodiment of the present invention. In the figure, the case 10 is composed of a cylindrical casing body 11 and a lid 12. The casing body 11 includes a partition wall 20 that horizontally divides the inside into an upper chamber and a lower chamber. The partition wall 20 is provided with a convex wall 21 for partitioning the peripheral portion and the central portion from each other in a circumferentially convex shape, and an outer window 22 communicating with the vertical direction is provided on the outer peripheral side of the convex wall 21. The breathable pad 2 is formed on the outer window 22.
3 is fixed. Further, a jet hole 24 is formed in the center of the inner wall of the convex wall 21, and the lower surface side of the jet hole 24 extends to the bottom of the casing body 11 and is a liquid fuel outlet pipe 25.
Are formed. A strainer 26 having a screen for filtration on its peripheral surface is arranged around the liquid fuel outlet pipe 25, and a jet 27 having a small diameter nozzle hole formed in the center of the jet hole 24. Is inset. The jet hole 24, the liquid fuel outlet pipe 25 and the jet 27 form a first fuel outlet passage.

The partition wall 20 is mounted on the cut portion 11a formed at the inner periphery of the casing body 11 at the peripheral edge thereof, and the partition wall 20 is formed.
An inner lid 28 whose outer periphery is formed in the same shape as the inner peripheral shape of the convex wall 21 is placed inside 1. The inner lid 28 has a window that communicates in the vertical direction, and the window has a mesh screen 29. A breathable pad 30 is placed above the window.

A communication hole 31 is formed in the center of the inner lid 28, and a suction pipe 32 projects downward from the lower opening of the communication hole 31.
The reference numeral 2 covers the jet hole 24 of the partition wall 20 to cover the periphery of the jet hole 24 and the side surface of the partition wall 2
A suction hole 33 communicating with the space sandwiched between the inner lid 28 and the inner cover 28 is provided. Further, a short cylinder 34 is formed in the upper opening portion of the communication hole 31, and a guide pipe 35 penetrating along the central axis of the casing body 11 is supported by the short cylinder 34. The lead-out pipe 35 is in close contact with the short cylinder 34. The communication hole 31, the suction pipe 32, the suction hole 33, the short cylinder 34, and the outlet pipe 35 form a second fuel outlet passage.

An introduction pipe 13 for connecting a flexible pipe communicating with a fuel tank (not shown) is fixed to a lower portion of the side surface of the casing body 11 and below the disconnection portion 11a, and a lid 12 is attached to the lid 12. Has a lead-out pipe 14 fixedly connected to an external intake system (not shown). The lead-out pipe 14 is connected to a diaphragm valve mechanism 15 which operates by negative pressure generated during engine operation. The diaphragm valve mechanism 15 puts the lead-out pipe 14 on the lower surface of the lid 12 when negative pressure is applied. Communication is performed, and when no negative pressure is applied, the communication is disabled.

A pressing lid 16 is inserted in the case 10. The pressing lid 16 supports the upper end of the lead-out pipe 35 at the center and forms a closed chamber with the lower surface side of the diaphragm valve mechanism 15. , The derivation pipe 35 at a predetermined time
The upper end of the pipe is communicated with the outlet pipe 14. A plurality of windows 17 are formed in the pressing lid 16, a filter 18 is placed above the windows 17, and a breathable pad 19 is arranged on the entire lower surface of the pressing lid 16.

Breathable pad 2 mounted on partition wall 20
Activated carbon 40, which is an adsorbent, is filled between 3, 30 and the breathable pad 19 arranged on the lower surface side of the pressing lid 16. The upper surface of the activated carbon 40 communicates with the outside air through the air-permeable pad 19, the filter 18 and the atmosphere communication hole formed in the lid 12. The casing body 1
A small chamber formed on the lower surface side of the partition wall 20 at the lower part of 1 is called a fuel reservoir chamber LR, and a small chamber formed on the upper surface side of the partition wall 20 with the inner lid 28 is called a purge chamber PR.

Next, the operation of this embodiment having the above structure will be described. At the time of assembling, the assembling parts in the case 10 are completed with the partition wall 20 as a base. That is, the partition wall 2
On the lower surface side of 0, the jet 27 is inserted into the jet hole 24, and the strainer 26 is fixed to the liquid fuel derivation pipe 25 by covering it. On the upper surface side of the partition wall 20, the inner pipe 28 is placed on the partition wall 20 while aligning the suction pipe 32 of the inner lid 28 with the jet hole 24 on the inner peripheral side of the convex wall 21 so that the suction pipe 32 faces the jet hole 24. The breathable pad 30 is placed on the air-conditioning pad 28, and the breathable pad 23 is placed on the outer collecting side of the convex wall 21. After that, the lead-out pipe 35 is inserted into the short cylinder 34 of the inner lid 28.

When these are completed, the lead-out pipe 35 is gripped and inserted into the casing body 11 with the strainer 26 facing down. Since the outer peripheral end of the partition wall 20 contacts the cut portion 11a of the casing body 11, the casing body 11 is filled with a predetermined amount of activated carbon 40 while closing the leading end of the lead-out pipe 35 in this state. After the filling, the pressing lid 16 having the breathable pad 19 and the filter 18 assembled therein is inserted into the casing body 11 to press the activated carbon 40 and support the upper end of the lead-out pipe 35.

On the other hand, with respect to the lid 12, the diaphragm valve mechanism 15 is assembled in advance, and the lid 12 is placed on the casing body 11 into which the pressing lid 16 is inserted to fix the periphery. This completes the assembly of the canister.
When the temperature rises, the vapor pressure of the fuel vapor generated in the fuel tank rises, and the fuel vapor enters the fuel reservoir LR through the introduction pipe 13 together with the air in the fuel tank, and the partition wall 20
Of the activated carbon 40 through the outer window 22 and the breathable pad 23. In the activated carbon 40 layer, the fuel vapor is adsorbed by the activated carbon 40, and only the air passes through the activated carbon 40 layer and goes out from the atmosphere communication hole of the lid 12 to the outside through the breathable pad 19 and the filter 18.

In some cases, the liquid fuel along with the vapor fuel vapor is introduced through the introduction pipe 13 into the fuel storage chamber L.
Although it may enter the R, such a liquid component is stored in the fuel storage chamber LR without permeating the activated carbon 40 layer. On the other hand, when the operation of the engine is started, the diaphragm valve mechanism 15 operates due to the negative pressure generated in the intake system,
The outlet pipe 14 and the outlet pipe 35 communicate with each other. Outlet pipe 14
Is connected to the intake system, a negative pressure of the intake system is applied to the purge pipe PR in which the discharge pipe 35 communicates with the discharge pipe 35 through the suction hole 33. Since the purge chamber PR communicates with the lower surface of the activated carbon 40 layer via the mesh screen 29 and the breathable pad 30, the negative pressure of the intake system is applied to the lower surface of the activated carbon 40 layer, so that the outside air is the atmosphere of the lid 12. It is sucked into the case 10 through the communication hole,
Further, it passes through 40 layers of activated carbon and is sucked into the purge chamber PR.

At this time, the outside air desorbs the fuel vapor adsorbed on the activated carbon 40, and the air containing the fuel vapor is sucked into the outlet pipe 14 from the outlet pipe 35 through the suction hole 33. By the way, the discharge pipe 3 from the purge chamber PR
When air containing fuel vapor is sucked into 5,
It flows in through the suction hole 33. A jet hole 24 is arranged in this inflow path, and a jet 27 having a small-diameter nozzle is fitted in the jet hole 24, so that the inflow path faces the inflow path when the flow velocity becomes faster. Negative pressure is generated on the jet 27 that is present. The other end of the jet 27 communicates with the bottom of the liquid fuel reservoir chamber LR via the liquid fuel outlet pipe 25. Therefore, when the liquid component of the fuel is stored in the liquid fuel reservoir chamber LR, the jet 2
When a negative pressure is generated above 7, the liquid component is sucked through the liquid fuel outlet pipe 25.

If the negative pressure is less than a predetermined amount, the liquid component is not sucked into the lead-out pipe 35, but when the negative pressure exceeds the predetermined amount, the lead-out pipe 3 is sprayed like a spray.
It is released within 5. However, even if the negative pressure becomes large, the amount of liquid that can pass through the jet 27 is limited, and a large amount of liquid will not be suddenly supplied to the intake system of the engine.

FIG. 3 shows the amount of fuel sucked from the outlet pipe. Ideally, as shown in graph A, when the flow rate of the vapor discharged from the canister reaches a predetermined amount, the discharge of the liquid component rises sharply, and after maintaining that amount for a while, it rapidly decreases. Good. In the conventional canister, when both the fuel vapor discharge hole 7 and the liquid fuel discharge hole 8 are filled with the liquid component, the discharge amount of the liquid component sharply rises from the beginning of engine operation and is discharged from the canister as shown in Graph B. It gradually decreases with the increase in the flow rate of steam. Therefore, if the stored flow rate of the liquid component is small, the discharge amount of the liquid component can be "0", which means that the fluctuation of the fuel supply amount during the low speed rotation is large.
It is difficult to perform good fuel control.

On the other hand, in the case of the canister of the present embodiment, as shown in graph C, the fuel discharge amount rises sharply when the rotation speed increases to some extent, and the relationship shown in the ideal state is obtained. be able to. In addition, the discharge amount and the like of the nozzle of the jet 27 and the suction hole 3 of the inner lid 28
3 can be changed and adjusted. By the way, if the liquid content is not stored in the liquid fuel storage chamber LR, the negative pressure in the outlet pipe 35 is also applied to the liquid fuel storage chamber LR via the jet 27, but the suction hole 33 Since it is sufficiently larger than the nozzle diameter of the jet 27,
A negative pressure is applied to the purge chamber PR to try to suck it from the chamber.

Further, the negative pressure applied to the purge chamber PR acts so as to be sucked also from the liquid fuel storage chamber LR via the activated carbon 40 layer, but at least the fuel vapor supplied from the fuel tank via the introduction pipe 13 is at least discharged. Liquid fuel storage chamber LR
It is necessary to enter the activated carbon 40 layer from the inside through the outer window 22 of the partition wall 20 and reach the inner lid 28 through a part of the activated carbon 40 layer. Therefore, it is possible to prevent the fuel vapor from being directly supplied to the intake system without passing through the adsorbent layer from the fuel tank unsuitable for fuel control. Further, this path can be adjusted by changing the height of the convex wall 21.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a canister according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of a jet arrangement portion.

FIG. 3 is a graph showing a suction amount of a liquid component of fuel.

FIG. 4 is a cutaway perspective view of a conventional canister.

[Explanation of reference numerals] 10 ... Case 13 ... Introducing pipe 14 ... Outflow pipe 20 ... Partition wall 24 ... Jet hole 25 ... Liquid fuel derivation pipe 27 ... Jet 28 ... Inner lid 32 ... Suction pipe 33 ... Suction hole 34 ... Short tube 35 ... Outlet pipe 40 ... Activated carbon LR ... Fuel storage chamber PR ... Purge chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazumi Yamazaki, 4-1 Chuo, Wako, Saitama Prefecture, Honda R & D Co., Ltd. (72) Creator: Masatoshi Udagawa, 1-1, Chuo, Wako, Saitama Incorporated in Honda R & D Co., Ltd. (72) Hideki Hoshino 1-4-1 Chuo, Wako-shi, Saitama Incorporated in Honda R & D Co., Ltd. (72) Inventor Tsutomu Mori Ishigami, Tenryu City, Shizuoka 199 (72) Inventor Suzuki Noboru 1940-1 Kamiishida-cho, Hamamatsu-shi, Shizuoka (72) Inventor Atsushi Suzuki 143 Sanwa-cho, Hamamatsu-shi, Shizuoka (56) References Japanese Patent Publication 4-32222 (JP, B2)

Claims (1)

[Scope of utility model registration request] 1. An adsorbent layer for fuel vapor, which is formed in the bottom of a case and which communicates with the fuel collection chamber at the bottom and communicates with the outside air at the top, is disposed in the case. In a canister including a first series passage that connects a fuel storage system of an engine to the fuel storage chamber, and a second communication passage that connects an intake system of the engine to the fuel storage chamber, the second communication passage includes: A purge chamber that faces a part of the lower surface of the adsorbent layer separately from the fuel reservoir chamber below the adsorbent layer, and a liquid fuel suction port that opens at the bottom of the fuel reservoir chamber below the adsorbent layer are provided. A first fuel derivation path having a small nozzle opening in the purge chamber at the top and the adsorbent layer vertically and penetrating from the purge chamber to the upper part of the nozzle opening of the first fuel derivation path. Sucking Canister, characterized in that it has a structure in which a second fuel outlet passage that forms a suction channel to the system.