Non-linear Model-based Predictive Control with Constraints for Controlled Auto-Ignition

Combustion with a high amount of recirculated exhaust gas is increasingly gaining interest. Such in part load conditions a low combustion peak temperature can be achieved which yields lowest emissions but suffers from instabilities of the process and a highly non-linear behavior. These properties make a closed-loop control a requirement for transient operation but also a challenge. The paper presents an innovative non-linear Model-based Predictive Controller (NMPC) for controlling the indicated mean effective pressure (IMEP) and crank angle of 50% released heat (CA50) while accounting for constraints on the maximum pressure rise (dpmax). The implementation of the controller is presented in a framework for rapid control prototyping (RCP) that enables the user to set up a complex controller for transient operation in a short time frame. The ability of the approach is proved by application to the real engine.