Carburetor utilizing fluidics

Claim 1

A carburetor comprising first means forming a main fuel flow system, said first means including a tubular flow duct for the passage of air therethrough, a Venturi member providing an annular constriction in said flow duct intermediate its ends, a throttle member positioned in said flow duct downstream in the direction of air flow therethrough from said Venturi member, a first jet deflection proportional fluid amplifier, a fuel injection nozzle opening into said flow duct at the location of said Venturi member, an output flow passage connecting said first fluid amplifier to said fuel injection nozzle, a negative pressure detecting nozzle opening into said flow duct at the location of said Venturi member, a control flow passage connecting said negative pressure detecting nozzle to said first fluid amplifier, wherein the improvement comprises second means forming a slow fuel flow system separate from said main fuel flow system, said second means including a second jet defection proportional fluid amplifier for injecting fuel into said flow duct, a second fuel injection nozzle opening into said flow duct at the location of said Venturi member for injecting fuel into said duct, a deflecting flow passageway connecting said second fuel injection nozzle and said second fuel amplifier, a negative pressure passage connected between said flow duct downstream from the position of said Venturi meter at the location of said throttle member for detecting the negative pressure generated by the speed of the air stream passing through the throttle portion of said flow duct for supplying fuel to said flow duct through said deflecting flow passage separate from the supply provided by said first fluid amplifier, said second fluid amplifier comprising an interaction chamber, a main jet supply port for introducing fuel into said interaction chamber, one end of said negative pressure passage connected to said main jet supply port upstream from said interaction chamber and three branch passages arranged in parallel extending between the other end of said negative pressure passage and said flow duct at the location of said throttle member within said flow duct, two of said branch passages forming negative pressure holes and the third branch passage forming a boost hole, said negative pressure passage having a constricted section intermediate its ends, an air inlet conduit connected to said negative pressure passage adjacent said constricted section on the side thereof remote from said main jet supply port, an adjustable negative pressure drop-down screw positioned in said air inlet conduit, an adjusting screw positioned within said branch passage forming said boost hole so that by means of said adjusting screw the branch passage forming the boost hole and the adjacent branch passage forming a negative pressure hole serve to adjust the degree of negative pressure introduced into said negative pressure passage.