Patent ID: 7908846

Claim:
A method for controlling injection of a substance in a diesel engine exhaust aftertreatment system, comprising: generating a feedforward signal as a function of a desired output signal, the desired output signal corresponding to an output sought to be achieved through injection of the substance; measuring actual system output and generating an actual output signal corresponding to an output actually achieved through injection of the substance; comparing the desired output signal and the actual output signal and generating an error signal corresponding to a difference between the desired output signal and the actual output signal; generating a control signal as a function of the error signal and the feedforward signal for controlling an amount of the substance to inject; adjusting the feedforward signal by an adaptive factor the adaptive factor being a function of the error signal; analyzing the error signal over time and adjusting the adaptive factor when a signal corresponding to an integral of the error signal is saturated; calculating a ratio of the integral of the error signal to the feedforward signal; and adjusting the adaptive factor when the signal corresponding to an integral of the error signal is saturated and the ratio exceeds a predetermined value.