Structure for suctioning back blow-back fuel
A first fuel storage portion is disposed on the upstream side of a fuel supply device of an engine so as to be contiguous with an air-intake passage of the fuel supply device. A blow-back suppression plate for suppressing blow-back from the air-intake passage is disposed between a filter element and the first fuel storage portion of an air cleaner. A suction-back passage is formed such that fuel accumulated in a fuel accumulation portion in the air cleaner is suctioned back through the suction-back passage into the air-intake passage. The suction-back passage allows communication between the fuel accumulation portion in the air cleaner and a suction-back port formed at the downstream-side end of the first fuel storage portion.
1. A structure for suctioning back blow-back fuel, the structure comprising:
a first fuel storage vessel disposed on an upstream side of a carburetor of an engine and contiguous with an air-intake passage of the carburetor;
a suction-back passage through which fuel accumulated in an air cleaner is suctioned back into the air-intake passage; and
a blow-back suppression plate disposed between a filter element of the air cleaner and the first fuel storage vessel and configured to suppress blow-back from the air-intake passage, wherein
the suction-back passage allows communication between a fuel accumulation container in the air cleaner and a suction-back port formed in the first fuel storage vessel,
the air cleaner includes a cleaner case connected to the carburetor, and a cleaner cap covering the cleaner case and the filter element, and
the suction-back passage is formed by:
the cleaner case;
a pair of projecting walls formed so as to be integrated with the cleaner case; and
the blow back suppression plate which is in contact with tip ends of the pair of projecting walls.
2. The structure for suctioning back blow-back fuel as claimed in claim 1 , further comprising
a blow-back prevention wall formed at an upstream-side end of the first fuel storage vessel, the blow-back prevention wall being opposed to an inlet of the air-intake passage and configured to prevent blow-back from the air-intake passage.
3. The structure for suctioning back blow-back fuel as claimed in claim 1 , wherein
the blow-back suppression plate is attached to the cleaner case.
4. The structure for suctioning back blow-back fuel as claimed in claim 1 , wherein
an area of the suction-back port is set to be sufficiently smaller than a cross-sectional area of the suction-back passage such that a suction effect due to intake air flowing in the air-intake passage is exerted.
5. The structure for suctioning back blow-back fuel as claimed in claim 1 , wherein
the blow-back suppression plate includes:
a blow-back suppression surface configured to suppress the blow-back; and
a portion of the air-intake passage through which intake air is allowed to pass, and
the blow-back suppression plate is configured to cover an inlet of the air-intake passage and be detachably fastened to the cleaner case.
6. The structure for suctioning back blow-back fuel as claimed in claim 1 , wherein
the fuel accumulation container is formed at a lower part in the cleaner case so as to be located between the cleaner case and the blow-back suppression plate, and
an inlet of the suction-back passage is formed in the fuel accumulation container.
7. The structure for suctioning back blow-back fuel as claimed in claim 1 , wherein
the first fuel storage vessel projects upstream from an inlet of the air-intake passage, which is formed in the cleaner case,
a second fuel storage vessel is formed on the cleaner case so as to extend along a part of a peripheral edge of the inlet of the air-intake passage, and
the second fuel storage vessel is contiguous with a side edge of the first fuel storage vessel, that extends along a direction of a flow of intake air.
8. The structure for suctioning back blow-back fuel as claimed in claim 1 , wherein
the carburetor includes an air path and an air-fuel mixture path, and
the suction-back port communicates with the air-fuel mixture path.