Patent Document ID: 5558064
Application ID: 08545125
Patent Flag: 1

Claim One:
1. An engine control method for generating a control signal applied to control an actuator to drive a value of an automotive internal combustion engine air/fuel ratio control parameter to a target air/fuel ratio parameter value, comprising the steps of: storing, in a memory device, a block learn array comprising a plurality of adjacent cells corresponding to a plurality of adjacent engine operating condition ranges, each of the plurality of cells having a cell value; repeatedly, (a) sensing a current engine condition, (b) determining whether a learn state is present in which the current engine condition is within any of the operating condition ranges of the block learn array, (c) if a learn state is present, then (i) identifying an active cell of the array as the block learn array cell having an engine operating condition range including the current engine condition and (ii) determining an active cell value by adjusting the cell value of the active cell in direction to drive the control parameter value toward the target parameter value, (d) if a learn state is not present, then (i) identifying an active cell of the array as the block learn array cell having an engine operating condition range closest to the current engine condition and (ii) determining an active cell value as the cell value of the active cell, (e) generating the control signal as a function of the determined active cell value, and (f) applying the control signal to control the engine air/fuel ratio control parameter; determining a value indicating a degree of deviation of the control parameter value away from the target parameter value; comparing the determined value to a predetermined threshold value over a predetermined monitoring period; adding a cell to the block learn array when the determined value exceeds the threshold value over the predetermined monitoring period; comparing cell values of at least one pair of neighboring cells in the block learn array over a predetermined comparing period; and reducing the number of cells of the block learn array when the cell values of the at least one pair are substantially the same over the predetermined comparing period.