Carburetors for internal combustion engines

Claim 1

FOR USE IN CONNECTION WITH AN INTERNAL COMBUSTION ENGINE TO BE CONTROLED BY AN OPERATOR, A CARBURETOR WHICH COMPRISES, IN COMBINATION, AN INDUCTION PIPE, A MAIN THROTTLE VALVE IN SAID INDUCTION PIPE DIRECTLY OPERATIVE BY THE OPERATOR, AN AUXILIARY THROTTLE VALVE IN SAID INDUCTION PIPE LOCATED UPSTREAM OF SAID MAIN THROTTLE VALVE, SAID AUXILIARY THROTTLE VALVE BEING MECHANICALLY INDEPENDENT OF SAID MAIN THROTTLE VALVE AND ARRANGED TO OPEN AUTOMATICALLY MORE AND MORE AS THE AIR FLOW RATE THROUGH SAID INDUCTION PIPE INCREASES, A CONSTANTLY OPEN PRIMARY AIR CONDUIT BY-PASSING SAID MAIN THROTTLE VALVE, SAID PRIMARY AIR CONDUIT HAVING AN INLET ORIFICE OPENING FROM A FIRST PORTION OF SAID INDUCTION PIPE LOCATED BETWEEN SAID TWO THROTTLE VALVES, AND A FIXED OUTLET ORIFICE OPENING DIRECTLY INTO A SECOND PORTION OF SAID INDUCTION PIPE LOCATED DOWNSTREAM OF SAID MAIN THROTTLE VALVE, SAID PRIMARY AIR CONDUIT AND SAID INLET ORIFICE BEING OF SUFFICIENTLY LARGE CROSS SECTION TO ENSURE, AT THE DOWNSTREAM END OF SAID CONDUIT, A PRESSURE SUBSTANTIALLY EQUAL TO THAT EXISTING IN SAID FIRST PORTION OF SAID INDUCTION PIPE AND SAID OUTLET ORIFICE BEING OF A CROSS SECTION SEVERAL TIMES SMALLER THAN THAT OF SAID CONDUIT, ANY PORTION OF SAID INDUCTION PIPE DOWNSTREAM OF SAID OUTLET ORIFICE BEING OF FIXED CROSS SECTION, A FUEL FEED CIRCUIT INCLUDING A VARIABLE CROSS SECTION FUEL FEED METERING ORIFICE AND A FUEL CONDUIT EXTENDING DOWNSTREAM OF SAID FUEL FEED METERING ORIFICE AND OPENING INTO SAID PRIMARY AIR CONDUIT OPPOSITE SAID OUTLET ORIFICE THEREOF, AND MEANS OPERATIVELY CONNECTED WITH SAID AUXILIARY THROTTLE VALVE FOR CONTROLLING THE CROSS SECTION OF SAID METERING ORIFICE IN ACCORDANCE WITH THE POSITION OF SAID AUXILIARY THROTTLE VALVE.