Claims
- 1. A variable venturi-type carburetor comprising:
- an axially-extending intake passage formed in the carburetor and having an inner wall of an approximately circular cross section;
- a suction piston transversely moveable in said intake passage from one side to another side thereof in response to a change in the amount of air flowing within said intake passage, said suction piston having a tip face which defines a venturi portion in said intake passage and has an upstream end portion; and
- a raised wall projecting from said another side of said intake passage immediately upstream of the upstream end portion of said suction piston, said raised wall having a substantially straight tip edge arcuately merging at the opposite ends thereof with the inner wall of said intake passage for defining an approximately D-shaped air inlet mouth of said intake passage upstream of said suction piston, the upstream end portion of the tip face of said suction piston having an approximately V-shaped cross section which expands toward said venturi portion, the straight tip edge and arcuate merging ends of said raised wall cooperating with the V-shaped upstream end to define an approximately isosceles triangular air inlet opening, said inlet opening gradually reducing in area as the suction piston approaches said another side when the amount of air flowing within said intake passage is reduced.
- 2. A variable venturi-type carburetor according to claim 1, wherein the tip face of said suction piston has a groove which opens to said intake passage upstream of said suction piston at the upstream end portion of the tip face of said suction piston, the V-shaped cross-section of said upstream end portion expanding from said groove toward said venturi portion.
- 3. A variable venturi-type carburetor according to claim 2, wherein said groove extends along the axis of said intake passage.
- 4. A variable venturi-type carburetor according to claim 2, wherein the tip face of said suction piston has a needle-mounting face on which a needle is mounted, said groove extending from the upstream end portion of the tip face of said suction piston to said needle-mounting face.
- 5. A variable venturi-type carburetor according to claim 2, wherein the tip face of said suction piston has a pair of inclined wall portions arranged on each side of said groove and extending to the upstream end portion of the tip face of said suction piston.
- 6. In a variable venturi carburetor having an axially-extending intake passage of substantially circular cross section and a suction piston moveable transverse said intake passage in response to changes in air flow through said intake passage, said suction piston having a tip face defining a venturi portion in said intake passage, a portion of said tip face having a substantially V-shaped cross section expanding towards said venturi portion, the improvement comprising:
- a raised wall portion projecting from the inner wall of said intake passage immediately upstream of said suction piston opposite said tip face and having a substantially straight tip edge the opposite ends of which smoothly, arcuately merge with the inside wall of said intake passage forming a substantially D-shaped inlet mouth upstream of said suction piston, the V-shaped portion of said tip face cooperating with the tip edge and arcuately merging ends of said raised wall to define an approximately isosceles triangular air inlet, said air inlet gradually reducing in area as the suction piston moves towards said venturi portion.
Priority Claims (1)
Number |
Date |
Country |
Kind |
56-209790 |
Dec 1981 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 06/404,831, filed Aug. 3, 1982, now abandoned.
US Referenced Citations (7)
Foreign Referenced Citations (1)
Number |
Date |
Country |
972281 |
Jan 1951 |
FRX |
Continuations (1)
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Number |
Date |
Country |
Parent |
404831 |
Aug 1982 |
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