Abstract: A method of distributing an error correction term over four grid points used in a normalized 3D lookup routine circulates a change in output of the normalized 3D lookup routine at a given position by a fixed error correction amount at a plurality of points related in proximity to an input value point. The magnitude of change for a given one of the plurality of break points is proportional to the slope change of the grid point from a read point. The proportional reverse interpolation process is particularly well adapted for use with a proportional-integral controller as may be used in the air/fuel ratio control system generating a fuel multiplier control signal in response to variations between an exhaust gas oxygen sensor signal and a command signal for the air/fuel ratio.

Abstract: A fuel control system for an internal combustion engine includes a processor for determination of the timing and length of control pulse signals to an injector driver for turning an injector on and off. The method and an apparatus for delivering fuel to the injectors is according to a schedule that is adjusted throughout a variety of operating conditions with a minimum of chronometric or throughput loading by scheduling a circular queue of a plurality of buckets determined as a predetermined portion of a combustion cycle. Each bucket is defined by an interval initiated by an event triggered interrupt. At the interrupt, the processor dequeues a list of pointers to fueling information data storage for each cylinder previously assigned to the bucket. The method then assigns each cylinder to at least one selected bucket according to predetermined logic determination and an injector demand signal.