Variable venturi type carburetor

Claim 1

A variable venturi type carburetor, comprising; a housing, a bore extending through said housing and having an inner wall defining an intake passage, a suction piston movably mounted in said housing and having a bottom end face projecting into said intake passage, said bottom end face of said suction piston and said inner wall of said intake passage defining a venturi, said suction piston moving up and down in response to a change in the vacuum produced in said intake passage located downstream of said venturi for maintaining the velocity of air flowing into said venturi at a constant value, a jet disposed on the inner wall of said intake passage at a position facing against said bottom end face of said suction piston, a needle fixed onto said bottom end face of said suction piston and entering into said jet, said jet and said needle defining an annular opening through which fuel is injected into said intake passage, a fuel reservoir in said housing; a fuel supply passage disposed in said housing and communicating said fuel reservoir with said jet, a pressure reducing device being disposed in said fuel supply passage for decreasing the pressure of the fuel contained in said fuel passage located between said jet and said pressure reducing device, said pressure reducing device comprising a check valve which only allows the outflow of fuel from said reservoir to said jet, an air bleed passage communicating said fuel supply passage with the atmosphere, and a bubble generating pipe made of sintered metal and disposed in said fuel passage at a position in which said air bleed passage opens into said fuel supply passage for creating fine bubbles of air in the fuel contained in said fuel supply passage.