A model based control of compressed natural gas injection systems

Low fuel consumption and low emissions are key issues in modern internal combustion engines design. For this reason, an effective on-line control of the injection process requires the mathematical equations describing the system dynamics. The inherent nonlinearities make the modeling of the fuel-injection system hard to accomplish. Moreover, it is necessary to trade off between accuracy in representing the dynamical behavior of the most significant variables and the need of reducing complexity to simplify the controller design process. In this paper we present a second order lumped parameters model of a Compressed Natural Gas injection system for control system synthesis and analysis. Based on the proposed model, we propose a generalized predictive controller to regulate the injection pressure, which guarantees good performances and robustness to modeling errors.