초록 ▼

A canister comprises a tank port communicated with an upper air chamber in a closed fuel tank, a purge port communicated with an intake passage of an engine, an atmospheric port opened to the atmosphere, and a main adsorbent chamber containing activated carbon, and the canister is further provided w

A canister comprises a tank port communicated with an upper air chamber in a closed fuel tank, a purge port communicated with an intake passage of an engine, an atmospheric port opened to the atmosphere, and a main adsorbent chamber containing activated carbon, and the canister is further provided with a partition plate between the tank port and the purge port for preventing both ports from being directly communicated with each other, so as to form a first chamber between the main adsorbent chamber and the tank port, and a second chamber between the main adsorbent chamber and the purge port, and a purge buffer plate is further provided in the main adsorbent chamber between the tank port and the purge port, for communicating between the first and second chambers with each other, the first chamber serves as an air chamber containing no activated carbon while the second chamber contains activated carbon. With this configuration, the canister has no external pipe line, the time change in fuel concentration of purged gas during treatment of evaporated fuel from the fuel tank is moderated in order to restrain an engine air-fuel ratio from being abruptly changed, and the operation ability of the engine can be satisfied.

대표청구항 ▼

The invention claimed is: 1. A canister comprising a tank port communicated with an upper air chamber in a fuel tank, a purge port communicated with an intake passage of an engine, an atmospheric port opened to atmosphere, and a main adsorbent chamber containing activated carbon for adsorbing evapo

The invention claimed is: 1. A canister comprising a tank port communicated with an upper air chamber in a fuel tank, a purge port communicated with an intake passage of an engine, an atmospheric port opened to atmosphere, and a main adsorbent chamber containing activated carbon for adsorbing evaporated fuel flowing from said tank port to said atmospheric port, wherein a partition plate is provided between said tank port and said purge port for preventing both ports from being directly communicated with each other, a first chamber is provided between said main adsorbent chamber and said tank port, a second chamber is provided between said main adsorbent chamber and said purge port, and a purge buffer plate is provided in said main adsorbent chamber on a side of said tank port/purge port, for communicating said first and second chambers with each other, and wherein said first chamber serves as an air chamber containing no activated carbon and said second chamber contains activated carbon. 2. A canister as set forth in claim 1, wherein an air-flow resistance between said first chamber and said main adsorbent chamber is set to be higher than that of said purge buffer plate between said fist and second chambers. 3. A canister as set forth in claim 1, wherein pulverized coal is used as the activated carbon contained in said second chamber, and granulated coal is used as the activated carbon contained in other adsorbent chambers. 4. A canister as set forth in claim 1, wherein an air-flow resistance of a filter provided in said main adsorbent chamber on a side of said tank port/purge ports is set per unit area to be higher than that of a filter provided in the second chamber on a side of said purge port and of a filter provided in said second chamber on a side of said main adsorbent chamber. 5. A canister as set forth in claim 1, wherein an adsorbent retaining plate is superposed on one side of a filter provided in said main adsorbent chamber on a side of the tank port/purge ports, and said adsorbent retaining plate is provided with at least one constriction hole, and a total air-flow resistance of said filter and said adsorbent retaining plate superposed with each other is set per unit area to be higher than that of a filter provided in said second chamber on a side of said purge port and of a filter provided in said second chamber on a side of said main adsorbent chamber. 6. A canister as set forth in claim 1, wherein said activated carbon contained in said second chamber is packed by a filter member wrapping it, but said activated carbon in other adsorbent chambers is not packed. 7. A canister as set forth in claim 1, wherein said second chamber containing the activated carbon has a capacity which is in a range of 1/1,400 to 10/1,400 with respect to a capacity of the fuel tank. 8. A canister as set forth in claim 1, wherein a vapor passage formed in said purge buffer plate is located on an upper side in said buffer plate in such a posture that said canister is installed in a vehicle. 9. A canister as set forth in claim 2, wherein pulverized coal is used as the activated carbon contained in said second chamber, and granulated coal is used as the activated carbon contained in other adsorbent chambers. 10. A canister as set forth in claim 9, wherein an air-flow resistance of a filter provided in said main adsorbent chamber on a side of said tank port/purge ports is set per unit area to be higher than that of a filter provided in the second chamber on a side of said purge port and of a filter provided in said second chamber on a side of said main adsorbent chamber. 11. A canister as set forth in claim 10, wherein an adsorbent retaining plate is superposed on one side of a filter provided in said main adsorbent chamber on a side of the tank port/purge ports, and said adsorbent retaining plate is provided with at least one constriction hole, and a total air-flow resistance of said filter and said adsorbent retaining plate superposed with each other is set per unit area to be higher than that of a filter provided in said second chamber on a side of said purge port and of a filter provided in said second chamber on a side of said main adsorbent chamber. 12. A canister as set forth in claim 11, wherein said activated carbon contained in said second chamber is packed by a filter member wrapping it, but said activated carbon in other adsorbent chambers is not packed. 13. A canister as set forth in claim 12, wherein said second chamber containing the activated carbon has a capacity which is in a range of 1/1,400 to 10/1,400 with respect to a capacity of the fuel tank. 14. A canister as set forth in claim 13, wherein a vapor passage formed in said purge buffer plate is located on an upper side in said buffer plate in such a posture that said canister is installed in a vehicle.