Spark ignition engine idle speed control using a novel framework and enabling control of the tradeoff between fuel consumption and load rejection capability

In this paper, a new framework for idle speed control is presented.(1) A simple new discrete event based engine model evolving in the crank domain is given and is parameterized using a combination of dynamic identification and steady state calibration. The majority of the nonlinearities can then be inverted and a second synthetic output is introduced. This second output is the torque reserve of the engine and enables control of the tradeoff between disturbance rejection capabilities and engine efficiency. A linear controller is designed using the H-infinity loopshaping technique and results are presented from dynamometer based engine tests.