Variable diffuser for carburetors

Claim 2

In a carburetor body of an internal combustion engine, a variable section, sonic flow diffuser, comprising: means for defining a circular intake passage in the carburetor body and a circular, fixed, divergent wall into which said circular intake passage opens; an obstacle in the form of a body of revolution and of a maximum diameter greater than that of said intake passage being disposed in said carburetor body in said circular, fixed, divergent wall, coaxial with said divergent wall and said intake passage; means for adjusting the position of said obstacle along the axial path of said intake passage and said circular divergent wall; such that a sonic flow, circular, divergent nozzle is formed, the annular throat of which is formed between the exit periphery of said intake passage and the nearest portion of the surface of said obstacle, and the variation in the gas flow cross-section of which is due to the variation of the radius of such section with respect to the flow axis wherein said obstacle has a plane circular surface oriented perpendicular to the axis of said intake passage, facing said passage, the fixed circular wall of said carburetor opposite said surface diverging slightly with respect thereto and wherein said intake passage forms the first barrel of a two-barrel carburetor, the air flow of which is controlled by the axial adjustment of said obstacle, said means for adjusting the position of said obstacle comprising an axial control rod extending through the air filter of said carburetor for axially adjusting said obstacle.

Claim 3

In a carburetor body of an internal combustion engine, a variable section, sonic flow diffuser, comprising: means for defining a circular intake passage in the carburetor body and a circular, fixed, divergent wall into which said circular intake passage opens; an obstacle in the form of a body of revolution and of a maximum diameter greater than that of said intake passage being disposed in said carburetor body in said circular, fixed, divergent wall, coaxial with said divergent wall and said intake passage; means for adjusting the position of said obstacle along the axial path of said intake passage and said circular divergent wall; such that a sonic flow, circular, divergent nozzle is formed, the annular throat of which is formed between the exit periphery of said intake passage and the nearest portion of the surface of said obstacle, and the variation in the gas flow cross-section of which is due to the variation of the radius of such section with respect to the flow axis, the fixed ciruclar wall of said carburetor opposite said surface diverging slightly with respect thereto and wherein said intake passage forms the first barrel of a two-barrel carburetor, the air flow of which is controlled by the axial adjustment of said obstacle, said means for adjusting the position of said obstacle comprising an axial control rod extending through the air filter of said carburetor for axially adjusting said obstacle wherein said obstacle has radial grooves of increasing flow section disposed on its circular diverging surface forming a wall of said nozzle, allowing a minimum sonic intake flow to be maintained even when said obstacle is drawn by said control rod up against the wall of said carburetor to thereby close said nozzle throat.

Claim 4

In a carburetor body of an internal combustion engine, a variable section, sonic flow diffuser, comprising: means for defining a circular intake passage in the carburetor body and a circular, fixed, divergent wall into which said circular intake passage opens; an obstacle in the form of a body of revolution and of a maximum diameter greater than that of said intake passage being disposed in said carburetor body in said circular, fixed, divergent wall, coaxial with said divergent wall and said intake passage; means for adjusting the position of said obstacle along the axial path of said intake passage and said circular divergent wall; such that a sonic flow, circular, divergent nozzle is formed, the annular throat of which is formed between the exit periphery of said intake passage and the nearest portion of the surface of said obstacle, and the variation in the gas flow cross-section of which is due to the variation of the radius of such section with respect to the flow axis, the fixed ciruclar wall of said carburetor opposite said surface diverging slightly with respect thereto and wherein said intake passage forms the first barrel of a two-barrel carburetor, the air flow of which is controlled by the axial adjustment of said obstacle, said means for adjusting the position of said obstacle comprising an axial control rod extending through the air filter of said carburetor for axially adjusting said obstacle wherein said obstacle has radial grooves of increasing flow section disposed on its circular diverging surface forming a wall of said nozzle, allowing a minimum sonic intake flow to be maintained even when said obstacle is drawn by said control rod up against the wall of said carburetor to thereby close said nozzle throat.