JPH0315812Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) This invention relates to a carbon canister that is installed in automobile engines and the like to prevent evaporated fuel from dissipating into the atmosphere.

(Prior Art) A carbon canister is used that temporarily adsorbs fuel gas that evaporates from a gasoline tank or the like of an internal combustion engine onto an adsorbent such as activated carbon, and releases it to the intake pipe side during engine operation. An example is shown in FIG. The fuel gas evaporated from the gasoline tank 50 is guided into the container 32 through the introduction pipe 31 of the carbon canister 30 and is once adsorbed by the adsorbent 33. During engine operation, the purge valve 34 is opened and the fuel gas is discharged from the discharge pipe 35 into the intake air of the engine. The fuel gas is discharged to the downstream side of the throttle valve 52 of the pipe 51. Purge valve 3
4 is the pipe end opening 3 of the discharge pipe 35 as shown in FIG.
5a is covered with a plate-shaped valve body 40 fixed to a diaphragm 39. The purge valve 34 is divided by the diaphragm 39 into an upper negative pressure chamber 41 and a lower purge chamber 45. A spring 42 is disposed inside the negative pressure chamber and presses the diaphragm through a retainer 43. Negative pressure chamber 41 communicates with the upstream side of throttle valve 52.

(Problems to be Solved by the Invention) In the conventional carbon canister 30 as described above, the throttle valve 52 is closed during engine idling, so negative pressure does not act on the negative pressure chamber 41 and the purge valve closes. 34 is closed. Discharge pipe 3
A negative pressure of about 500 to 600 mmHg is acting inside the chamber. When the throttle valve 52 is opened and the negative pressure in the intake pipe reaches the negative pressure chamber 41, the purge valve 34 is suddenly opened, and the negative pressure in the discharge pipe is impulsively transferred from the pipe end opening 35a of the discharge pipe to its outer peripheral passage. and further into the container. When the valve opens, an air impact sound (air bong) is generated and accompanied by vibration. Further, in the fully open position, the valve body 40 collides with the stopper 44, producing a collision sound (solid boom) and vibration.

This is because when the valve body 40 leaves the tube end opening 35a, since the valve body 40 is attached to the center of the diaphragm 39, the valve body leaves the opening without tilting.

(Means for Solving the Problem) In this invention, the plate-shaped valve body of the purge valve of the carbon canister is mounted eccentrically from the center of the diaphragm.

(Function) Since the carbon canister of this invention has the above structure, when the negative pressure of the intake pipe acts on the negative pressure chamber and suctions the diaphragm, the valve body is provided eccentrically from the center of the diaphragm. The center of the diaphragm first moves away from the opening at the end of the discharge pipe, creating a gap, and the diaphragm tilts open as if peeling off. Therefore, when the valve is opened, the passage first expands from the throttled state. This also slows down the initial upward speed of the valve body, reducing collisions with the stopper and reducing vibration.

(Embodiment) FIG. 2 shows a carbon canister 1 according to an embodiment of this invention, and FIG. 1A shows its purge valve 2. In FIG. 2, a carbon canister 1 includes an inlet pipe 3 and a discharge pipe 4, and stores activated carbon 7 as an adsorbent in a container 6 having an atmosphere communication hole 5 in the bottom. A purge valve 2 is provided at the top of the container 6. As shown in FIG. 1, the purge valve 2 is located at an eccentric position (l ₁ <
_Diaphragm 10 with a plate-shaped valve body 9 fixed to it
(FIG. 1B) into an upper negative pressure chamber 11 and a lower purge chamber 12, and the purge chamber communicates with the container 6 and is provided with an opening 4a at the end of the discharge pipe 4. Negative pressure chamber 11 communicates with the upstream side of throttle valve 52 (see FIG. 3) of the engine intake pipe, and a spring 13 is disposed inside to press valve body 9 via retainer 14 to close opening 4a. ing. As in FIG. 3, the other end of the introduction pipe 3 communicates with the fuel tank 50, and the other end of the discharge pipe 4 communicates with the downstream side of the throttle valve 52.

When the engine is operated, intake pipe negative pressure is transmitted to the discharge pipe 4. When the throttle valve opens, a negative pressure is generated in the negative pressure chamber, and an upward pulling force acts on the center of the diaphragm, so that the valve body 6 is tilted so as to be peeled off from the center and away from the opening 4a. Furthermore, since the initial upward velocity of the valve body 9 becomes slower, collision with the stopper 15 is also alleviated.

(Effect of the invention) Since the carbon canister of this invention has a fixed valve body eccentric from the center of the diaphragm of the purge valve, the valve opens as described above by sequentially expanding the passage from the throttled state. Since the initial velocity of the body's rise is also slower, the collision with the stopper is alleviated, and the generation of noise due to air impulsion, collision noise, and vibration accompanying the opening of the valve can be prevented.

[Brief explanation of drawings]

FIG. 1A is an example of the purge valve according to this invention, and FIG. 1B is a diagram of its diaphragm. Figure 2 shows an example of this invention. FIG. 3 is a diagram showing a state in which a carbon canister is installed, and FIG. 4 is a diagram of a conventional purge valve. DESCRIPTION OF SYMBOLS 1... Carbon canister, 2... Purge valve, 4... Discharge pipe, 4a... Opening, 9... Valve body, 10... Diaphragm, 13... Spring, 15... Stopper.

Claims (1)

[Scope of utility model registration request] The adsorbent is stored in a container equipped with an inlet pipe and a discharge pipe, and has an atmosphere communication hole in the bottom, and is further divided by a diaphragm into a negative pressure chamber and a purge chamber communicating with the inside of the container. In the canister, the canister is provided with a purge valve that opens the pipe end of the discharge pipe, and closes the pipe end opening with a valve body that has a spring disposed in a negative pressure chamber and is fixed to a diaphragm. A carbon canister characterized by being fixed at a position eccentric from the center of the diaphragm.