Back bleed choke mixture control

Claim 1

IN A FUEL CHARGING SYSTEM FOR AN INTERNAL COMBUSTION ENGINE, AN AIR INTAKE PASSAGE, A BUTTERFLY TYPE CHOKE VALVE PIVOTALLY MOUNTED OFF-CENTER IN SAID PASSAGE TO BE URGED FROM ITS CLOSED POSITION IN RESPONSE TO THE AIR FLOW IN SAID PASSAGE, A THROTTLE VALVE OPERABLY MOUNTED IN SAID PASSAGE DOWNSTREAM OF SAID CHOKE VALVE, A FUEL BOWL, MEANS FOR MAINTAINING A PREDETERMINED FUEL LEVEL IN SAID BOWL, A VENTURI RESTRICTION IN AN INTERMEDIATE PORTION OF SAID PASSAGE BETWEEN SAID VALVES, A FUEL METERING DUCT CONNECTING SAID BOWL WITH SAID INTERMEDIATE PORTION OF SAID PASSAGE TO DISCHARGE METERED FUEL THEREINTO, MEANS FOR MAINTAINING A PREDETERMINED PRESSURE RELATIONSHIP IN SAID INTERMEDIATE PORTION WITH RESPECT TO TEMPERATURE WHEN SAID ENGINE IS IDLING OR OPERATING UNDER LOAD COMPRISING THERMOSTATIC MEANS RESPONSIVE TO AN ENGINE OPERATING TEMPERATURE FOR URGING SAID CHOKE VALVE TOWARD ITS CLOSED POSITION WITH INCREASING FORCE AS SAID TEMPERATURE DECREASES, MEANS FOR PREDETERMINED THE PRESSURE DIFFERENTIAL BETWEENT HE FUEL PRESSURE IN SAID BOWL AND AT SAID DISCHARGE END OF SAID FUEL METERING DUCT WHEN SAID CHOKE VALVE IS CLOSED DURING CRANKING OF SAID ENGINE INCLUDING DUCT MEANS IN COMMUNICATING WITH SAID FUEL BOWL AND HAVING FIRST AND SECOND RESTRICTED PORTIONS VENTING SAID BOWL RESPECTIVELY TO THE ATMOSPHERE AND TO SAID INTERMEDIATE PORTION OF SAID PASSAGE, AN AIR CHAMBER COMPRISING PART OF SAID DUCT MEANS AND HAVING SAID SECOND RESTRICTED PORTION OPENING THEREFROM INTO SAID PASSAGE, AN ACCELERATION FUEL PUMP OPERATIVELY CONNECTED WITH SAID BOWL TO RECEIVE FUEL THEREFROM AND HAVING A RESTRICTED OUTLET OPENING INTO SAID CHAMBER IN ALIGNMENT WITH SAID SECOND RESTRICTED PORTION FOR DISCHARGING FUEL THEREINTO UPON OPERATION OF SAID PUMP, SAID CHAMBER BEING IN COMMUNICATING WITH THE ATMOSPHERIC THROUGH SAID FIRST RESTRICTED PORTION.