Choke control system for internal combustion engine

摘要

A first choke valve is mounted in a main intake passage carrying a lean mixture to a main combustion chamber, and a second choke valve is mounted in an auxiliary intake passage carrying a rich mixture to a relatively small auxiliary chamber. Spark ignition of the mixture in the auxiliary combustion chamber projects a flame through a torch nozzle connecting the chambers to ignite the lean mixture in the main combustion chamber. Control of the main choke valve for moderately cold starting or extremely cold starting is accomplished automatically by means of a control element driven by a heat responsive bimetal element, or by means of a manually operated control element. In either case, overtravel of the control element after the main choke valve closes stores energy in a spring to increase closing torque of the main choke valve, and also moves the auxiliary choke valve toward closed position, to improve engine startability under extremely cold conditions. Both choke valves open in response to complete firing of the engine.