초록 ▼

A general-purpose engine fuel tank fuel vapor treatment system includes: a canister mounted on a peripheral part of a fuel filler opening of a fuel tank mounted on a general-purpose engine, the canister housing a fuel adsorbent for adsorbing fuel vapor generated in the interior of the fuel tank; and

A general-purpose engine fuel tank fuel vapor treatment system includes: a canister mounted on a peripheral part of a fuel filler opening of a fuel tank mounted on a general-purpose engine, the canister housing a fuel adsorbent for adsorbing fuel vapor generated in the interior of the fuel tank; and an air vent provided in a tank cap fitted into the filler opening of the fuel tank. The air vent has an inner end opening in the interior of the fuel tank, and an outer end opening to the atmosphere. The canister is connected to the air vent. The interior of the fuel tank is made open to the atmosphere via the canister and the air vent. Thus, need for special piping is eliminated and fuel vapor within the fuel tank is treated while always stably maintaining the interior of the fuel tank at atmospheric pressure.

대표청구항 ▼

The invention claimed is: 1. A general-purpose engine fuel tank fuel vapor treatment system comprising: a canister mounted on a peripheral part of a fuel filler opening of a fuel tank mounted on a general-purpose engine, the canister housing a fuel adsorbent for adsorbing fuel vapor generated in an

The invention claimed is: 1. A general-purpose engine fuel tank fuel vapor treatment system comprising: a canister mounted on a peripheral part of a fuel filler opening of a fuel tank mounted on a general-purpose engine, the canister housing a fuel adsorbent for adsorbing fuel vapor generated in an interior of the fuel tank, wherein an air vent is provided in a tank cap fitted into the filler opening of the fuel tank, the air vent having an inner end opening in the interior of the fuel tank and an outer end opening to the atmosphere; the canister is connected to the air vent and has a T-shaped cross-section corresponding to a vertical cross-sectional shape of the tank cap; and the interior of the fuel tank is made open to the atmosphere via the canister and the air vent. 2. The general-purpose engine fuel tank fuel vapor treatment system according to claim 1, wherein the tank cap is formed from a cap inner part comprising a bottomed cylindrical portion inserted into and latched to the fuel filler opening and a flange portion protruding radially from upper end of the bottomed cylindrical portion to come into intimate contact with the fuel tank in an area around the fuel filler opening, and a cap outer part fitted onto and fixed to an outer periphery of the flange portion; the canister being disposed between the cap inner part and the cap outer part so that an interior of the tank cap is divided into a first vent chamber communicating with the interior of the fuel tank and a second vent chamber communicating with the atmosphere; and the canister is provided with a first communication hole and a second communication hole communicating with the first vent chamber and the second vent chamber, respectively. 3. The general-purpose engine fuel tank fuel vapor treatment system according to claim 2, wherein the first communication hole of the canister is disposed so as to open in an upper part of the first vent chamber, and a dividing wall for separating the first and second communication holes is disposed in the interior of the canister. 4. A general-purpose engine fuel tank fuel vapor treatment system comprising: a canister mounted on a peripheral part of a fuel filler opening of a fuel tank mounted on a general-purpose engine, the canister housing a fuel adsorbent for adsorbing fuel vapor generated in an interior of the fuel tank, wherein an air vent is provided in a tank cap fitted into the filler opening of the fuel tank, the air vent having an inner end opening in the interior of the fuel tank and an outer end opening to the atmosphere; the canister is connected to the air vent; and the interior of the fuel tank is made open to the atmosphere via the canister and the air vent, wherein the canister is of an annular shape and is mounted on an inner wall of the fuel tank in proximity to the fuel filler opening and surrounds a cylindrical portion of the tank cap, which protrudes into the fuel tank through the fuel filler opening; and wherein the canister is provided with a first communication hole opening in the interior of the fuel tank and a second communication hole leading to the air vent in the interior of the tank cap fitted into the fuel filler opening. 5. The general-purpose engine fuel tank fuel vapor treatment system according to claim 4, wherein the canister is fitted around an outer peripheral face of the cylindrical portion of the tank cap fitted into the fuel filler opening; and an annular chamber is defined above the canister, the annular chamber surrounding the tank cap and providing communication between the second communication hole and the air vent of the tank cap. 6. A general-purpose engine fuel tank fuel vapor treatment system comprising: a canister mounted on a peripheral part of a fuel filler opening of a fuel tank mounted on a general-purpose engine, the canister housing a fuel adsorbent for adsorbing fuel vapor generated in an interior of the fuel tank, wherein an air vent is provided in a tank cap fitted into the filler opening of the fuel tank, the air vent having an inner end opening in the interior of the fuel tank and an outer end opening to the atmosphere, the interior of the fuel tank opening to the atmosphere via the canister and the air vent, and wherein the canister comprises a first communication hole and a second communication hole, which are connected to said air vent and a dividing wall provided inside the canister and extending vertically, the canister being adapted to permit flow of air along a passage inside the canister between the first and second communication holes, said passage inside the canister including a portion in which air flows upwardly along the wall and another portion in which air flows downwardly along the wall. 7. The general-purpose engine fuel tank fuel vapor treatment system according to claim 6, wherein said first communication hole is formed at an upper portion of the canister. 8. The general-purpose engine fuel tank fuel vapor treatment system according to claim 6, wherein the tank cap is formed from a cap inner part comprising a bottomed cylindrical portion inserted into and latched to the fuel filler opening and a flange portion protruding radially from an upper end of the bottomed cylindrical portion to come into intimate contact with the fuel tank in an area around the fuel filler opening, and a cap outer part fitted onto and fixed to an outer periphery of the flange portion; the canister, which has a T-shaped cross-section corresponding to a vertical cross-sectional shape of the tank cap, is disposed between the cap inner part and the cap outer part so that an interior of the tank cap is divided into a first vent chamber communicating with the interior of the fuel tank and a second vent chamber communicating with the atmosphere; and said first communication hole and said second communication hole communicate with the first vent chamber and the second vent chamber, respectively. 9. The general-purpose engine fuel tank fuel vapor treatment system according to claim 8, wherein the first communication hole of the canister is disposed so as to open in an upper part of the first vent chamber. 10. A general-purpose engine fuel tank fuel vapor treatment system comprising: a canister mounted on a peripheral part of a fuel filler opening of a fuel tank mounted on a general-purpose engine, the canister housing a fuel adsorbent for adsorbing fuel vapor generated in an interior of the fuel tank, wherein an air vent is provided in a tank cap fitted into the filler opening of the fuel tank, the air vent having an inner end opening in the interior of the fuel tank and an outer end opening to the atmosphere, the canister being connected to the air vent and the interior of the fuel tank opening to the atmosphere via the canister and the air vent, and wherein the canister has a cylindrical portion positioned around the filler opening of the fuel tank, and a latching member for retaining the tank cap onto the fuel tank is mounted on the tank cap so as to be capable of moving inside the inner end of the air vent provided at the tank cap, said cylindrical portion of the canister extending vertically over an area corresponding to the inner end of the air vent. 11. The general-purpose engine fuel tank fuel vapor treatment system according to claim 1, wherein the canister is provided with a communication hole at an upper portion of the canister, the communication hole being connected to the air vent on a side of said inner end. 12. The general-purpose engine fuel tank fuel vapor treatment system according to claim 10, wherein the canister is provided with a communication hole at an upper portion of the canister, said communication hole being connected to the air vent on a side of said inner end. 13. The general-purpose engine fuel tank fuel vapor treatment system according to claim 10, wherein the tank cap is formed from a cap inner part comprising said cylindrical portion of a bottomed shape inserted into and latched to the fuel filler opening and a flange portion protruding radially from an upper end of the bottomed cylindrical portion to come into intimate contact with the fuel tank in an area around the fuel filler opening, and a cap outer part fitted onto and fixed to an outer periphery of the flange portion; the canister, which has a T-shaped cross-section corresponding to a vertical cross-sectional shape of the tank cap, is disposed between the cap inner part and the cap outer part so that an interior of the tank cap is divided into a first vent chamber communicating with the interior of the fuel tank and a second vent chamber communicating with the atmosphere; and the canister is provided with a first communication hole and a second communication hole communicating with the first vent chamber and the second vent chamber, respectively. 14. The general-purpose engine fuel tank fuel vapor treatment system according to claim 13, wherein the first communication hole of the canister is disposed so as to open in an upper part of the first vent chamber, and a dividing wall for separating the first and second communication holes is disposed in the interior of the canister.