Camless engine valvetrain: Enabling technology and control techniques

The camless valvetrain is considered as enabling technology by automotive engineers. It eliminates the cam-crank shaft mechanical linkage and allows a wide continuously variable valve timing and engine optimization. Engines with camless valvetrains are difficult to control with conventional on-board tuning schemes because the camless valvetrain (i) interacts with many subsystems with conflicting requirements, and (ii) fundamentally changes the dynamics of the engine breathing process.; In this dissertation, we provide insight and quantify the difficulties associated with two control problems in camless engines, namely, the actuator control problem and the engine management problem during idle and unthrottled conditions. A nonlinear physics-based model of an electro-mechanical camless valvetrain actuator is developed and validated on a bench-top experiment we designed and assembled. Dynamical analysis and feedforward control schemes are then investigated. A second nonlinear model of the engine breathing and speed dynamics during camless, idle, and unthrottled conditions is developed and partially validated using engine-dynamometer data. We employ classical and modern control techniques and software tools in our analysis and control synthesis. The two control-oriented models and the experimental setup we develop can be used for further system analysis and control design. In addition, the models can be used to determine optimum combinations of engine parameters without assembling and testing prototypes.