Abstract
The engine control design is becoming one of the most challenging aspects in the new generation Diesel engine development. It has to control precisely more and more complex engine technologies while dealing with increasing stringent pollution limits. An engine model is a very flexible tool to perform a large amount of tests over a wide range of operating conditions and to access to more detailed information than those available with experiments. Therefore, the use of the numerical engine simulation in the control development process can significantly reduce the test time needed on real hardware while providing more information for understanding the system physics. Based on high-performance physical models such as HCCI combustion model, the virtual engine simulator is able to support the control design from controller development to real-time calibration. The aim of this communication is to show the relevance of using such a model-based approach for current control issues. The demonstration is achieved through the challenging case of Diesel HCCI combustion engine. As an alternative to expensive and complex after-treatment solutions, Diesel HCCI engine takes benefit of high exhaust gas recirculation rate to limit in-cylinder pollutant production. Therefore, it is recognized as one of the most promising ways for new generation of CI engines but also one of the most complex engine technologies to control due to the sensitiveness of HCCI combustion mode to small perturbations. The paper presents each stage of the use of virtual engine simulator for the control design process applied to a 2.2 liter turbocharged HCCI Diesel engine fitted with a variable nozzle turbine and a highpressure EGR loop. At first, it describes in details the virtual engine simulator design and calibration according to bench data under steady state and transient operating conditions. Then, the utilisation of the virtual engine simulator for the control purposes is presented, from controller/observer development to complete real-time validation and engine or vehicle pre-calibration.
Keywords:Engine modelling, HCCI, engine control, real-time simulation.