JPS6321716Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a fuel vapor control device. Specifically, depending on the engine state and operating conditions, the fuel vapor adsorbed and stored in the canister is purged and introduced into the engine intake system. The present invention relates to a fuel vapor control device for controlling fuel vapor.

FIG. 1 shows a conventional fuel vapor control device. This fuel vapor control device consists of a pipe 2 whose one end is opened in the upper space 1a of the fuel tank 1, the other end of which is connected to the inlet 3a of the canister 3, and a pipe 4 whose one end is connected to the outlet 3b of the canister 3. The other end is connected to the suction pipe 5a of the engine 5, and a diaphragm type control valve 6 is interposed in the pipe 4, and this control valve 6 is operated by the negative pressure of the suction pipe 5a. The fuel vapor in the canister 3 is introduced into the suction pipe 5a during operation.

In such a conventional fuel vapor control device, since the operation of the control valve 6 relies on the negative pressure in the suction pipe 5a, it is not only extremely unstable, but also requires fuel supply during deceleration, for example. This results in the inconvenience that fuel vapor is supplied to the suction pipe 5a even when not in use. In addition, in FIG. 1, the reference numeral 7
8 is a transmission case, 8 is a carburetor, 9 is an air cleaner, and 10 is a negative pressure pipe.

For this reason, in the above control device, it is conceivable to use a solenoid valve instead of the diaphragm type control valve 6 to more reliably normalize the operation of the fuel vapor control device.

2 and 3, a solenoid valve 11 is connected to the pipe 4.
This figure shows a fuel vapor control device with an intervening fuel vapor control device.

The control device shown in FIG. 2 includes a detection means 12 for detecting the rotation speed of, for example, a crankshaft (not shown) of the engine 5, and uses an output signal from the detection means to detect a specific rotation range of the crankshaft (for example, The solenoid valve is opened in a rotation range exceeding the idling rotation range.

In addition, in the control device shown in Fig. 3, the timer 1
3, and depending on the timer, the starter switch 14 of the engine 5 or the ignition switch 1
5 is closed, and after a predetermined period of time has elapsed after that detection, the solenoid valve 11 is opened. Note that the above-mentioned predetermined time is, for example, the time from when the engine 5 is started until it enters a normal warm-up operation state;
It is determined as appropriate, taking into account the purpose of use and the environmental conditions under which it will be used. In addition, 16 is pipe 2
A separator interposed between the two separates gas and liquid.

Here, the structure of the canister will be briefly explained. FIG. 4 shows the internal structure of a conventional canister 3. As shown in FIG. In Fig. 4, 16 is the casing;
17, 18, and 19 are check valves, 20 is a partition tube, 21 is a lid integrally having check valves 17, 18, and 19, 22 is an atmosphere opening, 23 is an internal filter, and 24 is a filter on the side of the atmosphere opening 22. ,
25 is activated carbon as an adsorbent placed between the filters 23 and 24.

In this canister 3, the fuel vapor in the upper space 1a of the fuel tank 1 is introduced into the casing 16 via the separator 16, the pipe 2 and the check valve 18, and the fuel vapor is further introduced into the partition tube through the filter 23. Activated carbon 2 guided by 20
5 and adsorbed on the activated carbon. When negative pressure is generated in the suction pipe 5a, the check valve 19 is opened. At this time, the atmosphere (purge air) is introduced into the casing 16 through the atmosphere opening 22 due to the negative pressure, and the fuel vapor adsorbed from the activated carbon 25 is removed by this purge air. As a result, this separated fuel vapor is introduced into the suction pipe 5a via the check valve 19 and the pipe 4.

In this way, according to the control device shown in FIGS. 2 and 3, fuel vapor is stably supplied into the intake pipe. By the way, in each of the above control devices,
As the electromagnetic valve opens and closes, fuel vapor stored in the canister is supplied to the suction pipe or the supply is cut off. As a result, the air-fuel ratio suddenly changes, resulting in an unstable engine operating condition. Additionally, fuel vapor is removed from the adsorbent using negative pressure inside the suction pipe, but the removal efficiency is not always good, and there are cases where sufficient fuel vapor cannot be supplied into the suction pipe. It was hot.

This invention was made in view of the above circumstances,
It is an object of the present invention to provide a fuel vapor control device that can stabilize the operation of an engine and can also efficiently separate fuel vapor from an adsorbent.

In this invention, the electromagnetic switching valve is operated according to the engine operating conditions to supply fuel vapor with different concentrations to the intake system depending on the engine operating conditions, and the electromagnetic switching valve is buried in the adsorbent and the coil The above objective is achieved by heating the adsorbent with the heat generated by the adsorbent.

Hereinafter, a fuel vapor control device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 shows an embodiment of the fuel vapor control device according to the present invention. In FIG. 5, the same elements as those shown in FIG. 4 are given the same reference numerals.

In this control device, one end 26a is connected to the canister 3.
A pipe 26 opened in the upper space 3a of the
A pipe 27 with one end 27a opened into activated carbon 25 as an adsorbent near the filter 24 via a filter 28, a pipe 29 connected to a check valve 19, and the other ends of the pipes 26 and 27 are selected as the pipe 29. and an electromagnetic switching valve 30 for communicating with each other. In the figure, 30a is the valve body of the electromagnetic switching valve 30, 30b is the lead wire of the electromagnetic switching valve 30, and 30c
is a coil of an electromagnetic switching valve 30, and the electromagnetic switching valve 30 is embedded in activated carbon 25 as shown. Further, in the figure, reference numeral 31 is a coupler, 32 is a throttle opening detection means for detecting the opening of a throttle valve (not shown), 32a is a throttle opening detection sensor section thereof, and 32b is a detection sensor section 3 thereof.
A switch 2a is activated by the output, 33 is an ignition switch, and 34 is a battery. These elements constitute operating means for operating the electromagnetic switching valve 30.

Next, the operation of this control device will be explained, and the configuration of this control device will be further clarified.

In this control device, when the engine is in an idling state, the throttle valve is closed, so the switch 32b of the throttle opening detection means 32 is opened. In this case, the electromagnetic switching valve 30 is not operated, and the electromagnetic switching valve 30
Communication between the pipe 26 and the pipe 29 is cut off by the valve body 30a, and the pipe 27 and the pipe 29 are communicated with each other. At this time, the fuel vapor existing in the vicinity of one end 27a of the pipe 27, that is, the fuel vapor whose concentration has been reduced by being mixed with the atmosphere in the lower space 3b of the canister 3, is transferred to the pipe 27 and the electromagnetic switching valve 3.
0, pipe 29, check valve 19 and pipe 4 into a suction pipe (not shown).

Further, in this control device, when the engine leaves the idling state and enters the normal operating state, the throttle opening detection sensor section 32a detects this state and closes the switch 32b. In this case, the electromagnetic switching valve 30 has its coil 30c
is activated by being excited, and the valve body 30a of the electromagnetic switching valve 30 connects the pipe 26 and the pipe 2.
9 are communicated with each other, and communication between the pipes 27 and 29 is cut off. At this time, the highly concentrated fuel vapor existing in the upper space 1a of the purged canister 3 flows through the pipe 26, the electromagnetic switching valve 30, and the pipe 2.
9, is introduced into the suction pipe via the check valve 19 and the pipe 4. Further, by heating the activated carbon 25 by the coil 30c that is excited and generates heat, separation of fuel vapor from the activated carbon 25 is promoted, and a large amount of fuel vapor is supplied to the upper space 1a of the canister 3. Ru.

Note that the actuating means for actuating the electromagnetic switching valve 30 is not limited to the above-mentioned embodiment, and the actuating means shown in FIGS.
It is also possible to employ the detection means 12 and timer 13 shown in the figure.

Further, in the above embodiment, one end 26 of the pipe 26
a is opened into the upper space 3a of the canister 3, and one end 27a of the pipe 27 is opened into the activated carbon 25 near the filter 24.
The present invention is not limited to this, but one end 26a of the pipe 26
is opened into the activated carbon 25 near the filter 23,
One end 27a of the pipe 27 may be opened into the lower space 3b of the canister 3 through a filter.In short, one end 26a of the pipe 26 may be opened at a location where relatively high concentration fuel vapor exists. , one end 27a of the pipe 27 may be opened at a location where fuel vapor of relatively low concentration exists.

As described above, according to the fuel vapor control device according to the present invention, the electromagnetic switching valve is operated according to the operating conditions of the engine, and fuel vapor with different concentrations is introduced into the intake system according to the operating conditions of the engine. This makes it possible to operate the engine stably. In addition, since the electromagnetic switching valve is embedded in the adsorbent in the canister, the heat generated by the coil promotes the separation of fuel vapor from the adsorbent, and as a result, it is possible to increase the concentration of fuel vapor in the canister, and the adsorption It has become possible to reuse the fuel vapor adsorbed by the agent without waste.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram showing a conventional fuel vapor control device, Figs. 2 and 3 are conceptual diagrams showing an improved fuel vapor control device, and Fig. 4 is a cross section showing the structure of a conventional canister. 5 are sectional views showing the main parts of the fuel vapor control device according to the present invention. 3...Canister, 3a...Upper space, 3b
... lower space section, 16 ... casing, 19 ...
Check valve, 20... Partition tube, 21... Lid, 22... Atmospheric opening, 23... Inside filter, 24... Atmospheric opening side filter, 25... Activated carbon, 26, 27, 29... Pipe ,26a,2
7a... One end, 28... Filter, 30... Solenoid switching valve, 30a... Valve body, 30b... Lead wire,
30c...Coil, 31...Coupler, 32...Throttle opening detection means, 32a...Throttle opening detection sensor section, 32b...Switch, 33...
Ignition switch, 34...battard.

Claims (1)

[Scope of utility model registration request] In a fuel vapor control device that purges fuel vapor adsorbed and accommodated in a canister and introduces it into the intake system of the engine depending on the state and operating conditions of the engine, one end is placed near an internal filter in the canister. a second pipe having one end opened in the vicinity of the air release port side filter in the canister; a third pipe having one end connected to the air intake system; an electromagnetic switching valve that selectively connects the pipe and the second pipe to the third pipe; and an actuating means that operates the electromagnetic switching valve; By operating the switching valve in one direction, the highly concentrated fuel vapor present near the other end of the first pipe is introduced into the intake system, and the switching valve is operated in one direction. A fuel vapor control device characterized in that the fuel vapor having a low concentration near the other end of the second pipe is introduced into the intake system by operating in the opposite direction.