JPH0245498Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) This invention relates to an evaporative gas purge device for a motorcycle that returns evaporative gas collected in a canister to the engine intake side during engine operation.

(Prior Art) Evaporated (fuel) gas that evaporates in a fuel tank while a motorcycle is stopped is collected in a main canister so as not to be released into the atmosphere. When the engine starts, the collected evaporative gas is sucked together with purge air through the evaporative gas purge pipe by the negative intake pressure of the engine intake system, and is sent from the intake passage into the engine cylinder where it is combusted.

By the way, the canister is constructed as shown in FIG. 1A, and a sealed container 1 is filled with activated carbon 2, and the activated carbon 2 adsorbs and collects evaporated gas. However, among the evaporated gases, light component gases are not necessarily sufficiently adsorbed by the activated carbon 2, and may pass through and be dissipated into the atmosphere from the atmosphere opening 3. In order to adsorb light component gases, increasing the amount of activated carbon increases the size of the canister, which imposes various restrictions in terms of cost and installation space.

In order to prevent the canister from increasing in size, the main canister 5a and the auxiliary canister 5b are connected in series.
There is one in which the auxiliary canister 5b is opened to the atmosphere through the atmosphere opening 6. However, in this case, when purging the evaporative gas collected in the canisters 5a and 5b into the engine intake system through the evaporative gas purge pipe 7, the ventilation resistance is large, and the evaporative gas is desorbed in the auxiliary canister 5b. may be adsorbed again by the intake agent 8 such as activated carbon within the main canister 5a, resulting in problems such as poor desorption efficiency of the collected gas.

(Problem to be solved by the invention) This invention takes into account the above points, improves the adsorption capacity of evaporated gas without increasing the size of the canister, and also effectively desorbs the collected evaporative gas during evaporative gas purging. It is an object of the present invention to provide an evaporative gas purging device for a motorcycle that can be used to purify a motorcycle.

[Structure of the idea]

(Means for Solving the Problem) In order to solve the above-mentioned problems, the evaporative gas purge device for a motorcycle according to this invention is equipped with a canister that collects evaporative gas in a fuel tank. A main canister connected to the tank and an auxiliary canister connected to the main canister via a communication part are provided, and the main canister and the auxiliary canister are opened to the atmosphere when the collected evaporated gas is desorbed. A switching valve that can be opened on each side is provided, and each evaporative gas purge pipe from the main canister and the auxiliary canister is connected to the engine intake side.

(Function) This evaporative gas purging device for a motorcycle is constructed as described above, and the main canister and the auxiliary canister are connected through the communication part, so there is no need to increase the size of the canister, and the ability to adsorb evaporative gas is improved. can be improved.

In addition, a switching valve is provided in the communication section between the main canister and the auxiliary canister, and the main canister and the auxiliary canister are opened to the atmosphere when the evaporative gas is desorbed, so that the evaporative gas collected in each canister can be desorbed. can be carried out effectively.

(Embodiments) Hereinafter, preferred embodiments of this invention will be described with reference to the accompanying drawings.

FIG. 2 shows an evaporative gas purging device for a motorcycle according to this invention. In the figure, reference numeral 10 is a main canister that collects evaporative gas evaporated in a fuel tank 11. This main canister 10 has one side. evaporative gas introduction pipe 12 and evaporative gas purge pipe 13
is provided. The evaporative gas introduction pipe 12 enters the fuel tank 11 , and its tip opens above the liquid level to guide the evaporative gas in the fuel tank 11 to the main canister 10 .

On the other hand, the evaporative gas purge pipe 13 is connected to the intake passage 16 of the engine intake system 15, and the main canister 1
The evaporated gas collected at 0 is purged into an intake passage (intake manifold) 16. The purged evaporated gas is supplied from the intake passage 16 into the cylinders of the engine 17 and is combusted.

The main canister 10 has an airtight container 20 filled with an adsorbent 21 such as activated carbon.
adsorbs evaporated gas. The main canister 10 is connected to an auxiliary canister 24 via a communication pipe 22 serving as a communication section. The auxiliary canister 24 also has an airtight container 25 filled with an adsorbent 26 such as activated carbon, and an evaporative gas purge pipe 27 from the other side is connected to an air cleaner 28 .

The evaporative gas purge pipes 13 and 27 of the main canister 10 and the auxiliary canister 24 are connected to the engine intake system 15, but if the evaporative gas purge pipes 13 and 27 are connected together to the intake passage 16 on the engine 17 side, the engine negative pressure increases. There is a risk of change. In extreme terms, the engine negative pressure becomes smaller and the force of intake from the carburetor 33 becomes weaker, and the carburetor 33 is adversely affected by engine negative pressure fluctuations. To effectively prevent this, the main canister 1
Connect the evaporative gas purge pipe 13 from 0 to the intake passage 16 on the engine 17 side, and connect the evaporative gas purge pipe 27 from the auxiliary canister 24 to the engine intake system 16.
It is preferable to connect to the air cleaner 28 side, which is the upstream side of the air cleaner 28. Since the auxiliary canister 24 of the evaporative gas purge pipe 27 connected to the air cleaner 28 side is originally a sub-canister, it is sufficient to purge (desorb) the evaporative gas collected in this auxiliary canister 24 little by little.

On the other hand, a switching valve 30 is provided in the middle of the communication pipe 22 that connects both the canisters 10 and 24. The switching valve 30 is formed to be able to be selectively switched between a communication position shown by a solid line in which both the canisters 10 and 24 are communicated with each other, and an open position shown by a chain line in which both the canisters 10 and 24 are opened to the atmosphere, respectively. It is switched to the open position during evaporative gas purge (desorption) such as when starting the engine. At this time, the main canister 10 and the auxiliary canister 2
4 is opened to the atmosphere through the atmosphere communication pipes 31a and 31b, respectively, and purge air is supplied to the canister 1.
0.24. The switching valve 30 is a fuel negative pressure control, a solenoid,
It is automatically switched to the open position when evaporative gas is desorbed due to negative pressure in the engine intake system.

Note that the reference numeral 33 is a carburetor, and the reference numeral 34 is an engine transmission case.

Next, the operation of the evaporative gas purge device for a motorcycle will be explained.

While the engine of the motorcycle is stopped, the switching valve 30 is held in the communication position. The evaporative gas evaporated in the fuel tank 11 is guided to the main canister 10 and the auxiliary canister 24 through the introduction pipe 12, and is adsorbed by the adsorbents 21 and 26, such as activated carbon, filled in both canisters 10 and 24. and collected. Therefore, it is possible to prevent the evaporated gas from being dissipated into the atmosphere.

When the engine is started, the switching valve 30 is switched to the open position, and each canister 10, 24
is opened to the atmosphere through the atmosphere communication pipes 31a and 31b, and purging of the collected evaporated gas is started. During this evaporative gas purge, the evaporative gas collected in the main canister 10 due to the intake negative pressure of the engine intake system 15 is desorbed and sucked into the intake passage 16, and then from this intake passage 16 to the engine 17.
The fuel is supplied to the cylinder and undergoes combustion treatment. Desorption of the collected evaporated gas is facilitated and accelerated by the purge air sucked from the atmosphere communication pipe 31a.
On the other hand, the evaporated gas (mainly light component gas) collected in the auxiliary canister 24 is desorbed by the negative pressure of the air cleaner 28 and the purge air flowing in from the atmosphere communication pipe 31b, and is sucked into the air cleaner 28 and sent to the engine intake system 15. The fuel is sent to the engine and burned in the engine cylinder.

Figures 3A and 3B show a first variation of this invention.

The evaporative gas purging device for a motorcycle shown in this modification is provided with a four-way switching valve 35 as a switching valve in the middle of the communication pipe 22 that connects the main canister 10 and the auxiliary canister 24. This four-way switching valve 35 has a communication position where both canisters are communicated with each other (see FIG. 3A), and a communication position where both canisters 10,
24 to the atmosphere (see FIG. 3B). The switching operation of the four-way switching valve 35 is automatically switched by a fuel negative pressure switch, a solenoid, or the intake negative pressure of the engine intake system 15.

The rest of the structure is the same as that shown in FIG. 2, so the same reference numerals are given and the explanation will be omitted.

FIGS. 4A, B, and C show a second modification of this invention.

What is shown in this second modification is a communication pipe 2 connecting the main canister 10 and the auxiliary canister 24.
A rotary type switching valve 36 is provided in the middle of 2. This switching valve 36 is provided with a communication port 38 that allows the communication pipes 22 to communicate with each other, and open ports 39a, 39b that are open to the atmosphere.
Communication position where 4 are communicated with each other (see Figure 4B)
and the open position to open to the atmosphere (see Figure 4 C)
It is designed to switch between the two in conjunction with starting and stopping the engine.

In the explanation of the embodiment of this invention, an example was explained in which the main canister and the auxiliary canister were connected in series through a communication pipe.
The number is not necessarily limited to two, and three or more may be connected in series.

[Effect of idea]

As mentioned above, in the evaporative gas purging device for a motorcycle according to this invention, since the main canister and the auxiliary canister are connected through the communication part, there is no need to increase the size of the canister, and the evaporative gas is transferred to one canister. Even if it passes through without being adsorbed, it will be effectively adsorbed and collected by the next canister, thereby preventing it from being released into the atmosphere.
When connecting the main canister and auxiliary canister,
The ability to trap evaporated gas is improved compared to a single canister having the same amount of adsorbent such as activated carbon. Furthermore, since a main canister and an auxiliary canister are used, the mounting space can be flexible even in cases where mounting space is subject to various restrictions, such as in a motorcycle.

Furthermore, a switching valve is provided in the communication pipe that communicates the main canister and the auxiliary canister, which can be switched to the atmosphere open side when the evaporative gas collected in both canisters is removed. Since I connected each to the intake side,
When purging evaporative gas, by switching the switching valve and opening each canister to the atmosphere, the collected evaporative gas is smoothly desorbed by the negative intake pressure in the engine intake system when the engine is started and the purge air flowing into each canister. , the desorption performance is improved.

[Brief explanation of the drawing]

Figures 1A and B are sectional views showing a conventional canister attached to a motorcycle, Figure 2 is a diagram showing an embodiment of an evaporative gas purge device for a motorcycle according to this invention, and Figures 3A and B are sectional views of a conventional canister attached to a motorcycle. FIGS. 4A, B and C are diagrams showing a first modification of the invention, and FIGS. 4A, B and C are diagrams showing a second modification of the invention. 10...Main canister, 11...Fuel tank,
12...Evaporative gas introduction pipe, 13...Evaporative gas purge pipe, 15...Engine intake system, 16...Intake passage, 17...Engine, 21, 26...Adsorbent,
22...Communication pipe, 24...Auxiliary canister, 27
...Evaporative gas purge pipe, 28...Air cleaner,
30, 36...Switching valve, 35...Four-way switching valve.

Claims (1)

[Claims for Utility Model Registration] 1. In an evaporative gas purge device equipped with a canister that collects evaporative gas in a fuel tank, a main canister connected to the fuel tank and a main canister connected to the main canister through a communication part. and an auxiliary canister, and the communication portion is provided with a switchable switching valve that opens the main canister and the auxiliary canister to the atmosphere when the collected evaporated gas is desorbed, and the main canister and the auxiliary canister An evaporative gas purge device for a motorcycle, characterized in that each evaporative gas purge pipe from the evaporative gas purge pipe is connected to an engine intake side. 2. The switching valve is a four-way switching valve that can be selectively switched between a communication position where the main canister and the auxiliary canister communicate with each other and an open position where both the canisters are opened to the atmosphere. An evaporative gas purge device for a motorcycle according to claim 1. 3. The evaporative gas purge device for a motorcycle according to claim 1, wherein the evaporative gas purge pipe from the main canister is connected to the intake passage of the engine intake system, and the evaporative gas purge pipe from the auxiliary canister is connected to the air cleaner.