Abstract: A multiple cylinder two-stroke fuel-injected internal combustion engine is operated at idle by interrupting the fuel injection stages in a predetermined pattern such that over a certain number of crankshaft revolutions a fewer number of injections occur than over the same number of revolutions at non-idle. The quantity of fuel injected per injection is increased relative to that required to operate the engine at idle wihtout any injection interruptions. Spark timing is also advanced.

Abstract: A code system for a device (30) that exhibits an input-output relationship characterized by an off-set and substantially linear performance (gain) comprising a resistor network (20) in cirucit with the device's coil (22), indicative of the device's GAIN and OFF-SET wherein the values of GAIN and OFF-SET are intrinsically coded within the value of a single resistor.

Abstract: A voltage doubler circuit and system incorporating a plurality of such circuits for energizing in an alternating sequential manner a greater plurality of fuel injectors arranged in groups corresponding to the number of voltage doubler circuits.

Abstract: An electronic control unit for regulating the air/fuel ratio of an internal combustion engine is disclosed. The electronic control unit has an open loop calibration for regulating air/fuel ratio that is corrected with a closed loop signal developed by an integral controller. The integral controller bases the closed loop correction signal on a signal from an exhaust gas composition sensor located in the engine exhaust manifold. Various conditions of the system are sensed by a closed loop sensor condition detector to provide information on whether the sensor is up to operating temperature and is operative. If the exhaust gas sensor is functioning and the operating system parameters indicate the system operation should move to closed loop control, the loop is closed by the condition detector. Included in the condition detector circuit is a timer whose cycle is RPM dependent.