| 摘要 |
PROBLEM TO BE SOLVED: To provide an evaporated fuel treatment device which uses a diaphragm valve for closing a vapor passage during purge, for suppressing the leakage of evaporated fuel into the atmosphere by supplying atmospheric pressure through a canister to a back pressure chamber of the diaphragm valve to enable the operation of the diaphragm valve during purge even when the back pressure chamber is not opened to the atmosphere.SOLUTION: A diaphragm valve 40 includes a diaphragm 41 partitioning a valve chamber 40a communicated with a vapor passage 34 and a back pressure chamber 40b, a valve element 42 provided in the diaphragm 41, and a pipe line 43 as part of the vapor passage 34 communicated with a canister 31, and having an opening end 44 arranged in opposition to the valve element 42 to abut thereon, the back pressure chamber 40b including a flow valve 52 communicated with the canister 31 via a first communication path 51 and with a fuel tank 21 via a second communication path 45, and adapted to be closed when the flow amount per unit time of air flowing via the communication paths 51, 45 from the fuel tank 21 to the side of the canister 31 is a predetermined value or greater.SELECTED DRAWING: Figure 1 |
