Abstract: A fuel control system for a spark ignition internal combustion engine of the type having a source of fuel and a pump for supplying the fuel from the fuel source and to the engine at variable flow rates. The fuel control system of the present invention is particularly suited for a reciprocating piston aircraft engine and is designed to minimize brake specific fuel consumption of the engine during steady state engine operation. The fuel control system utilizes a microprocessor to determine the peak value of the exhaust gas temperature and, once the peak has been found, repeatedly decreases the fuel flow rate to the engine in predetermined increments until the exhaust gas temperature is less than its peak value by a predetemined amount. At this time, the fuel control system maintains a constant fuel flow rate to the engine.

Abstract: A fuel control system is provided for a spark-ignition internal combustion engine having a source of fuel and means for supplying the fuel from the fuel source and to the engine at variable flow rates. The fuel control method of the present invention is particularly suited for a reciprocating piston aircraft engine and is designed to minimize brake specific fuel consumption of the engine during operation at constant engine rotational speed and load but is capable of supplying additional fuel to the engine during transient operation, for example during an acceleration phase. In brief, when the engine is operating under constant engine rotational speed and load, an engine parameter, such as the exhaust gas temperature, which is correlated to the brake specific fuel consumption for the engine is iteratively sensed and compared to the previously determined value for this parameter.