Adaptive air/fuel ratio controller for internal combustion engine

摘要

An air/fuel ratio controller for an internal combustion engine including two memories each having numbers stored at locations addressed by engine operating points with the locations addressed by the engine operating points being updated during closed loop operation in accord with the value of a closed loop adjustment of the air/fuel ratio. Each memory location in the first memory is updated during operation of the engine at the corresponding operating point in accord with an update time constant having a value so that the number stored tracks adjustment value producing the predetermined desired closed loop air/fuel ratio during varying values of engine operating parameters. Each memory location in the second memory is updated during operation of the engine at the corresponding operating point in accord with an update time constant having a value so that the number stored is the average of the values producing the predetermined closed loop air/fuel ratio during varying values of engine operating parameters. The first memory is used during closed loop operation to preset the closed loop adjustment at least when the engine first operates at an operating point and the second memory is utilized during open loop operation to adjust the air/fuel ratio by an amount determined at least in part by the number stored in the second memory at locations addressed by the engine operating point.