FUEL METERING CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINE

A fuel metering control system for an internal combustion engine including a feedback loop having an adaptive controller and an adaptation mechanism that estimates controller parameters .theta.. The adaptive controller corrects the quantity of fuel injection to bring a controlled variable obtained at least based on an output of said air/fuel ratio sensor, to a desired value. Estimation error of the controller parameters are defined by an error signal e*. The system is configured such that the signal is compared with a limit value and is replaced to a predetermined value when the calculated estimation error signal exceeds the limit value. Thus, the signal is determined to be a predetermined value.