A method and system for controlling an engine

摘要

A method and system for controlling EGR rate of an internal combustion engine 16 having an intake throttle 12 for controlling mass flow to an intake of the engine 16 and an EGR valve 14 for controlling flow from the exhaust of the engine 16 back to the intake of the engine 16 along with air passing through the intake throttle is disclosed. The method includes measuring a mass air flow passing to the intake throttle 12 and a desired mass air flow, producing an error signal representative of a difference between the measure mass air flow and the desired mass air flow and producing a pair of control signals in response to the error signal. The pair of control signals operate the intake throttle 12 and the EGR valve 14 to drive the error signal towards a null.