Development of Highly Premixed Combustion Diesel Model: From Simulation to Control Design

Abstract

<div class="htmlview paragraph">In the context of increasingly stringent pollution norms, reduced engine emissions are a great challenge for compressed ignition engines. After-treatment solutions are expensive and very complex to implement, while the NO<sub>x</sub>/PM trade-off is difficult to optimise for conventional Diesel engines. Therefore, in-cylinder pollutant production limitation by the HPC combustion mode (Highly Premixed Combustion) - including Homogeneous Charge Compression Ignition (HCCI) - represents one of the most promising ways for new generation of CI engine. For this combustion technology, control based on torque estimation is crucial: the objectives are to accurately control the cylinder-individual fuel injected mass and to adapt the fuel injection parameters to the in-cylinder conditions (fresh air and burned gas masses and temperature). The main goal is to preserve a precise torque balance during all engine working modes. 1D engine models are an essential tool to improve controller development efficiency, as they allow to easily sweep a large amount of operating conditions and to access accurate information on engine behavior. As a matter of fact, extending the part of the numerical models into the control design process can reduce the algorithm development time and the risks of damaging the prototype hardware.</div> <div class="htmlview paragraph">The contribution of this paper is twofold:</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">The design of a 4 cylinder HPC Diesel engine model: A specific validation of the combustion model is achieved for HCCI/conventional dual mode combustion by a study of model accuracy to reproduce the main combustion parameter variations such as SOI, injected fuel mass or burned gas rate. Then, a complete validation campaign on relevant steady state and transient operating conditions show good agreement between engine model behavior and testbed results.</div> </li> <li class="list-item"><div class="htmlview paragraph">The use of this model as a crucial support tool for two control development purposes: The validation of an individual cylinder AFR estimator and control using the reliable and available λ-sensor located downstream the turbine as the only measurement is presented. The design of an EGR observer in the intake manifold based on typical vehicle sensors is also achieved.</div> </li> </ul> </div>