JPH0245499Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an evaporative emission control device for a motorcycle, and more specifically, to an evaporative emission control device in which a canister is connected.

2. Description of the Related Art An evaporative emission control device is known in which evaporative gas in a fuel tank is temporarily stored in a canister, purified in the canister, and supplied to an engine without releasing the evaporative gas into the atmosphere.

FIG. 1 shows a general evaporative emission control device for motorcycles. This evaporative gas control device has one end of a tank pipe 2 opened in an upper space 1a of a fuel tank 1, the other end facing into the activated carbon layer of a canister 3, and one end opened outside the activated carbon layer inside the canister. The other end of the purge pipe 4 faces the intake passage of the carburetor 5. In this evaporative gas control device, evaporative gas in a fuel tank 1 is guided into activated carbon of a canister 3 through a tank pipe 2, and the gas is stored there and purified. The thus purified gas is sucked into the intake passage of the carburetor 5 through the purge pipe 4 by the negative pressure generated in the engine 6, and is further introduced into the engine 6. At this time, air is taken in from the air intake port 7 of the canister 3 due to negative pressure, and the purified gas is adjusted to an appropriate concentration. In addition, in Fig. 1, the reference numeral 8
indicates the air cleaner.

By the way, in such a conventional evaporative gas control device, particularly light components of the evaporative gas are difficult to be adsorbed by the activated carbon of the canister 3, and end up passing through the activated carbon layer and being released into the atmosphere from the air intake port 7. Therefore, in order to sufficiently adsorb such evaporated gas, it is possible to make the activated carbon layer thicker, but this increases the ventilation resistance when suctioning the evaporated gas into the intake passage of the vaporizer 5, reducing the suction efficiency. It will drop significantly.

In view of these problems, the purpose of this invention is to
It is an object of the present invention to provide an evaporative gas control device that sufficiently adsorbs evaporative gas and has high suction efficiency of purified gas.

That is, in the present invention, a main canister and a sub-canister are used, and these are connected to each other, so that when the engine is stopped, etc., evaporative gas is guided through the main canister to the sub-canister, and when the engine is running, the evaporated gas is guided to the sub-canister. The evaporated gas adsorbed by the activated carbon of each canister due to the negative pressure of the engine is transferred to the purge pipe installed in each canister along with the air taken in from the air intake port formed independently in each canister. The above purpose is achieved by guiding the air to the intake system.

The present invention will be described below with reference to embodiments shown in the drawings. FIG. 2 shows the canister part of the evaporative emission control device for a motorcycle according to the present invention.
Other parts are the same as those in Figure 1.

The canister section 20 of this evaporative gas control device is
The main canister 21 and the sub-canister 22 are connected through a communication pipe 23, an air intake port 24 is formed in the pipe, and a switching valve 25 is provided in association with the air intake port and the communication path 23a of the pipe. It is arranged. The main canister 21 is filled with activated carbon 27 between the filters 26 and 26 that define the inside of the canister, and the end of the tank pipe 2 penetrating the front wall 21a of the main canister 21 is filled in the activated carbon. and in the hollow part 28 between the front wall 21a and the filter 26,
The end of the purge pipe 4 penetrating the front wall 21a is exposed. The sub-canister 22 is filled with activated carbon 30 between the filters 29 and 29 that define the inside of the canister, and the hollow part 31 between the front wall 22a of the sub-canister 22 and the filter 29 is filled with activated carbon 30.
An air inlet 23 is formed in the rear wall 22b so that the end of the purge pipe 4' passing through the front wall 22a is exposed. And this subcanister 22
The front hollow part 31 of the main canister 21 and the hollow part 33 between the rear wall 21b of the main canister 21 and the filter 26 are communicated with each other by the communication pipe 23. In this communication pipe 23, the passage 23a is bent at the middle part, and the air intake port 24 is formed at the bent part. A valve body 34 of the switching valve 25 is arranged therebetween as a valve seat. The switching valve 25 has a spring 35
The valve body 34 is brought into pressure contact with the air intake port 24 side by the biasing force of
3a is opened to communicate the main canister 21 and the sub-canister 22, and the solenoid 36 is excited, and its magnetic force operates the valve body 34, opening the air intake port 24 and closing the passage 23a. It is something. In the switching valve 25 of this embodiment, the solenoid 36 is energized by turning on the ignition switch 37. Furthermore, in the embodiment, an on-off valve 38 is installed in the purge pipe 4' of the subcanister 22, a valve body 40 is urged by a spring 39 to close the passage 4'a, and a solenoid 41 is energized. The valve body 40 is operated to open the passage 4'a.
This on-off valve 38 is the switching valve 25 described above.
Similarly, when the ignition switch 37 is turned on, the solenoid 41 is energized.

The evaporative emission control device including such a canister section 20 operates as follows. engine 6
is stopped, that is, while the ignition switch 37 is not turned on, the switching valve 25
closes the air intake port 24 and opens the passage 23a, and the on-off valve 38 closes the passage 4'a. Therefore, the evaporated gas generated in the fuel tank 1 is introduced into the activated carbon 27 of the main canister 21 through the tank pipe 2, and most of it is adsorbed by the activated carbon, and a part of it that has passed through the activated carbon 27 is The evaporated gas is introduced into the activated carbon 30 of the subcanister 22 via the switching valve 23,
It is adsorbed on the activated carbon.

When ignition switch 37 is turned on,
The switching valve 25 is actuated to open the air intake port 24 and close the passage 23a, and the on-off valve 38 opens the passage 4'a. Therefore, the main canister 21 and the sub-canister 22 in this state are completely separated. Therefore,
When the engine 6 is started and negative pressure sufficient to suck evaporated gas is generated in the intake system, the negative pressure is applied to each canister 21, 2 via the purge pipes 4, 4'.
It acts on activated carbon 27, 30 of No. 2, and sucks the evaporated gas adsorbed therein into the intake passage of vaporizer 5 through purge pipes 4, 4' together with the air taken in from air intake ports 24, 32. Although not shown, the purge pipe 4' joins the purge pipe 4 at an appropriate point.

As described above, the evaporative gas control device for a motorcycle according to the present invention communicates the main canister and the sub-canister in series when the engine is stopped, thereby completely adsorbing the evaporative gas into the activated carbon. Further, the evaporative emission control device according to the present invention makes each canister independent at appropriate times during engine operation, thereby sucking evaporative gas directly from each canister into the intake system. , the intake efficiency is also extremely good.

[Brief explanation of the drawing]

Fig. 1 is a diagram conceptually showing a conventionally adopted evaporative emission control device for a motorcycle, and Fig. 2 is a sectional view showing the main parts of the evaporative emission control device for a motorcycle according to the present invention. . 1...fuel tank, 2...tank pipe, 4,
4'... Purge pipe, 5... Carburizer, 6... Engine, 20... Canister part, 21... Main canister, 22... Sub canister, 23...
Communication pipe, 23a... passage, 24... air intake port, 25... switching valve, 27, 30... activated carbon, 32... air inlet, 38... opening/closing valve.

Claims (1)

[Scope of claim for utility model registration] A main canister having a tank pipe and a purge pipe connected to each other at the front, a sub-canister having a purge pipe connected to the front and an air inlet at the rear, and an intermediate canister. a communication pipe having an air intake port in the main canister and connecting the rear part of the main canister and the front part of the sub-canister; a switching valve that communicates between the main canister and the sub canister, opens the air intake port when the ignition switch is turned on, and cuts off communication between the main canister and the sub canister; An on-off valve is provided on the connected purge pipe and closes the passage in a normal state, and opens the passage in conjunction with the switching valve when the ignition switch is turned on. An evaporative emission control device for motorcycles featuring: