JPH0324867Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present application relates to a carbon canister used for internal combustion engines.

Carbon canisters absorb and collect vaporized fuel released from the fuel reservoir of internal combustion engines.
This device then desorbs the vaporized fuel and sends it into the engine to burn it, thereby preventing the vaporized fuel from dispersing into the atmosphere.

A common structure is a cylindrical case that has a communicating pipe at one end and is open to the atmosphere at the other end, in which a carbon layer is provided via upper and lower filters. Furthermore, the drawbacks of this structure are:
In order to prevent the intake pipe from being filled with evaporated fuel reaching the carbon layer from the fuel reservoir and deteriorating the startability of the engine, a flow pipe 2 is inserted into the carbon layer 1, and the flow pipe 2 is inserted into the carbon layer 1. Structures that reduce the increase in flow path resistance have been proposed. (Figure 1).

Note that, by providing a plurality of communication pipes on the upper wall of the cylindrical case, the flow pipe 2 is provided at an eccentric position away from the axis of the cylindrical case 6.

In the lower filter 4 shown in FIG. Set to dimensions equal to the inner diameter. As a result, the lower filter 4 is attached to the cylindrical case 6.
and the outer periphery of the communication tube 2.

However, in the structure described above, in order to tightly insert the lower filter 4, first, the lower filter 4 is brought into close contact with the inner periphery of the cylindrical case 6, and then the insertion opening 5 and the flow pipe 2 are made coaxial. The procedure is to rotate the lower filter 4.

In this case, since the inner periphery of the cylindrical case 6 and the outer periphery of the lower filter 4 are in close contact with each other, smooth rotation cannot be obtained, resulting in the disadvantage that it takes time and effort to rotate and align the shafts in this way. Become.

Therefore, in order to make it possible to extremely easily assemble and replace the filters provided above and below the carbon layer, the present application has an insertion opening with an inner diameter smaller than the inner circumference of the case and equal to the outer diameter of the flow pipe. This objective is achieved by forming a filter with a filter piece having an outer diameter equal to the inner circumference of the case and an insertion opening having an inner diameter larger than the outer diameter of the flow pipe. It is something that

To explain with reference to an embodiment, FIG. 2 shows a carbon canister 10 of the present invention, with a communicating pipe 1 on one side.
A carbon layer 18 is provided in a cylindrical case 15, which has a cover plate 14 with a cover plate 14 provided therein, and the other side is open to the atmosphere, with upper and lower filters 16 and 17 interposed therebetween, and a flow pipe is provided in the carbon layer. 19 is inserted, its upper end communicates with the communication pipe 13, and its lower end is open to the outside of the carbon layer 18. The flow pipe 19 is provided eccentrically with respect to the axis of the cylindrical case 15. 19 is a partition ring. The lower filter 17 is 2
The filter piece 17a has an insertion opening 20a with a diameter equal to the outer diameter of the flow pipe 19, and the outer diameter is the same as that of the cylindrical case 1.
5. The inner diameter is smaller than 5. Further, the filter piece 17b has an insertion opening 20b having a diameter larger than the outer diameter of the flow pipe 19, and the outer diameter is larger than the outer diameter of the cylindrical case 1.
5. It has a value equal to the inner diameter. Lower filter 17
is held by a porous holding plate 21. Note that the flow pipe 19 may be porous, and a coarse filter 22 may be provided at the end of the flow pipe 19.

Evaporative fuel from the fuel tank flows into the case 15 through the communication pipe 11, is adsorbed on the carbon layer 18, and is absorbed into the carbon layer 18.
Retained. Evaporated fuel from the float chamber of the engine's carburetor flows out from the communication pipe 13 toward the distribution pipe 19 . Since the flow pipe 19 is not filled with carbon, the flow path resistance is small, and most of the evaporated fuel in the float chamber flows into the case 15 from the communication pipe 13. When assembling the lower filter 17 or when replacing the lower filter 17 if it becomes clogged, first insert the insertion opening 20a of the filter piece 17a into the outer periphery of the flow pipe 19 and insert the filter piece 17a into the case. 15. In this state, there is a gap between the outer periphery of the filter piece 17a and the inner periphery of the case. Next, the filter piece 17b is installed inside the case 15. In this case, the outer periphery of the filter piece 17b and the case 15
The inner periphery is in close contact, and there is a gap between the insertion port 20b and the outer periphery of the communication tube 19. in this way,
The filter pieces 17a, 17b are alternately brought into close contact with either the inner periphery of the case 15 or the outer periphery of the flow pipe 19.

Further, a porous holding plate 21 is disposed above the filter piece 17b, and the outer circumference of the holding plate is connected to the inner circumference of the case 15. In this way, the lower filter 17
is arranged inside the case 15. In the above embodiment, if the thickness of each of the filter pieces 17a and 17b is set to 1/2 the thickness of the conventional lower filter 4,
The economic burden will not increase much.

As described above, the carbon canister of the present invention has a cylindrical case that has a lid plate at one end with a communication pipe connected to the float chamber of the carburetor of an internal combustion engine, and whose other end is open to the atmosphere. A carbon layer is provided inside the cylindrical case via upper and lower filters, and a flow pipe communicating with the communication pipe is inserted eccentrically with respect to the axis of the cylindrical case within the carbon layer. A filter member having an insertion port having an outer diameter equal to and larger than the outer diameter of the flow pipe; and a filter member having an insertion port having an outer diameter smaller than the inner circumference of the case and an inner diameter equal to the outer diameter of the flow pipe. Therefore, it is not necessary to simultaneously position the filter on both the inner periphery of the case and the outer periphery of the flow tube, and the filter can be assembled and replaced very easily.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional carbon canister.
FIG. 2 is a sectional view of the carbon canister of the present invention. 11, 12, 13... Distribution pipe, 15... Cylindrical case, 16, 17... Filter, 18... Carbon layer, 17a, 17b... Filter piece.

Claims (1)

[Scope of utility model registration request] A carbon layer is provided through upper and lower filters in a cylindrical case that has a cover plate with a communication tube at one end and communicates with the atmosphere at the other end, and a flow tube that communicates with the communication tube is provided within the carbon layer. In a carbon canister for an internal combustion engine, which is inserted eccentrically with respect to the axis of a cylindrical case, the filter part has an insertion opening whose outer diameter is equal to the inner circumference of the case and larger than the outer circumference of the flow pipe; A carbon canister for an internal combustion engine, characterized in that the filter is formed by a filter piece having an insertion opening having an inner diameter smaller than the inner circumference of the case and equal to the outer diameter of the flow pipe.