Model-based Air and Fuel Path Control of a VCR Engine

Abstract: The objective of the work was to develop a basic control system for an advancedexperimental engine from scratch. The engine this work revolves around is a Saabvariable compression engine.A new control system is developed based on the naked engine, stripped of theoriginal control system. Experiments form the basis that the control system isbuilt upon. Controllers for throttles, intake manifold pressure for pressures lessthan ambient pressure and exhaust gas oxygen ratio are developed and validated.They were found to be satisfactory. The lambda controller is tested with severalparameter sets, and the best set is picked to be implemented in the engine. Modelsnecessary for the development and validation of the controllers are developed.These models include models for the volumetric efficiency, the pressure dynamicsof the intake manifold, the fuel injectors and wall wetting.