Diesel Engine Identification and Predictive Control using Wiener and Hammerstein Models (original) (raw)
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-Modélisation 0D des émissions polluantes Diesel : développement et utilisation d'une méthodologie de couplage entre un modèle de combustion Diesel 0D et un modèle de polluants-Afin de satisfaire les normes de pollution de plus en plus sévères, les constructeurs automobiles ont généralisé l'utilisation du contrôle électronique du moteur. Ce contrôle permet de s'assurer en permanence du fonctionnement optimum du moteur en adéquation avec la demande de couple du conducteur et le bon fonctionnement des organes de post-traitement. Le développement et la calibration des algorithmes de contrôle moteur ne peuvent se faire qu'avec une compréhension fine du comportement dynamique du groupe motopropulseur, couplé à sa ligne d'échappement. Jusqu'à présent, un grand nombre d'essais sur banc moteur et sur véhicule était nécessaire pour atteindre des niveaux de calibration suffisants pour le contrôleur. Afin de diminuer les coûts de production, il devient de plus en plus important de limiter ces essais expérimentaux en ayant recours à la simulation. Dans ce contexte, il est important de disposer de modèles de combustion et de polluants prédictifs, calibrés sur un nombre limité de points expérimentaux et utilisables sur une grande plage de points de fonctionnement moteur. Ce papier présente un modèle 0D de combustion Diesel, basé sur le modèle de Barba [Barba C. et al. (2000)-A Phenomenological Combustion Model for Heat Release Rate Prediction in High Speed DI Diesel Engines with Common Rail Injection, SAE Technical Paper 2000-01-2933], permettant en particulier de prendre en compte l'impact de la multi-injection sur le déroulement de la combustion. Le modèle répartit chaque injection en deux zones : une première pour la flamme de pré-mélange lors du début de la combustion et une autre pour la flamme de diffusion. Afin de simuler la production de polluants, un modèle de mélange indexé sur l'énergie cinétique turbulente générée par le spray a été introduit. Ce dernier modèle permet de créer une zone de gaz brûlés dans la chambre de combustion dans laquelle les émissions de CO, NO x et suies sont calculées. Les modèles de polluants sont d'abord validés en utilisant le logiciel CHEMKIN et des résultats de calculs 3D. Des résultats expérimentaux obtenus sur un moteur 4 cylindres Diesel à injection directe en fonctionnement stabilisé sont ensuite utilisés pour valider et calibrer le couplage entre le modèle de combustion et les modèles de polluants. Le simulateur ainsi calibré est enfin utilisé pour simuler un fonctionnement en transitoire de charge du moteur.