Mode Transition Control of a Sequential Parallel Turbocharged Automotive Diesel Engine

摘要

Sequential turbocharging systems switch between different modes for covering the full engine operating range. Operation mode selection of the sequential system is a key issue, because both performance reduction and system damage risks appear if the boosting system is not operated in the convenient mode. In addition, transition between operation modes is critical in the sense that it can induce non-negligible torque oscillations. Boosting system controls must ensure a proper mode selection and perform smooth mode transitions. This paper is devoted to the design and development of such control system. For that, simulations from a wave action model, real-life driving cycles from similar engines and experimental information from a prototype engine are combined. Transition criteria are defined on the basis of system performance and system damage risk (over-speed and compressor surge). On the other hand, transition is optimised by means of the proper synchronization of the control valves and corrective actions on the injected fuel mass.