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Restriction Model Independent Method for Non-Isentropic Outflow Valve Boundary Problem Resolution

Gipsa Lab-Emmanuel Witrant, Luc Dugard
RENAULT SAS-Felipe Castillo
Published 2012-04-16 by SAE International in United States
To meet the new engine regulations, increasingly sophisticated engine alternative combustion modes have been developed in order to achieve simultaneously the emission regulations and the required engine drivability. However, these new approaches require more complex, reliable and precise control systems and technologies. The 0-D model based control systems have proved to be successful in many applications, but as the complexity of the engines increases, their limitations start to affect the engine control performance. One of the 0-D modeling limitations is their inability to model mass transport time. 1-D modeling allows some of the 0-D models limitations to be overcome, which is the motivation of this work. In this paper, two quasi-steady outflow boundary models are developed: one is based on the isentropic contraction and the other on a momentum conservation approach. Both are compared with computational fluid dynamics (CFD) 3-D simulations. Then, an innovative method for solving the outflow boundary problem taking into account the entropy correction at the boundary for a 1-D unsteady gas flow modeling is presented. Its formulation allows more predictive quasi-steady…
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Energy Wall Losses Estimation of a Gasoline Engine Using a Sliding Mode Observer

Gipsa Lab-Emmanuel Witrant, Olivier Sename
Gipsa Lab France-Maria Adelina Rivas Caicedo
Published 2012-04-16 by SAE International in United States
This paper describes an innovative method to estimate the wall losses during the compression and combustion strokes of a gasoline engine using the cylinder pressure measurement. The estimation during the compression and combustion strokes allows to better represent the system during the combustion. A sliding mode observer is derived from a validated 0-D physical engine model and its convergence and stability are proved. The observer is validated using two different engine models: a one zone engine model and a two zones engine model with flame wall interaction. A good agreement between the estimation results and the model reference is observed, showing the interest of using closed loop strategies to estimate the wall losses in a SI engine.
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