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Optimal Control of Mass-transport Time-delay Model in a Low-pressure EGR

GIPSA-lab-Emmanuel Witrant
Grenoble INP-Didier Georges
  • Technical Paper
  • 2020-01-0251
To be published on 2020-04-14 by SAE International in United States
This paper presents the control-oriented model and control design of the burned gas ratio(BGR) transport phenomenon, witnessed in the intake path of an internal combustion engine, due to the redirection of burned gases to the intake path by the low-pressure EGR. Based on a nonlinear AMESim model of the engine, the BGR in the intake manifold is modeled as a state-space output time-delay model, or alternatively as an ODE-PDE coupled system, that take into account the time delay between the moment at which the combusted gases leave the exhaust manifold and that at which they are readmitted in the intake manifold. In addition to their mass transport delay, the BGRs in the intake path are also subject to inequality constraints because they are positive percentages lying between 0 and 100. The objective of the control problem is to track a reference output profile of the BGR in the intake manifold, taking into account the transport delay and the state(output) and input constraints of the system. In this aim, two indirect optimal control approaches are implemented…
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Intra-Pipe Restriction Non-Homentropic Boundary Resolution Method

GIPSA Lab Renault SAS-Felipe Castillo
GIPSA Lab UJF Grenoble 1/CNRS-Emmanuel Witrant, Luc Dugard
Published 2013-04-08 by SAE International in United States
A complete non-homentropic boundary resolution method for a flow upstream and downstream an intra-pipe restriction is considered in this article. The method is capable of introducing more predictable quasi-steady restriction models into the boundary problem resolution without adding artificial discharge coefficients. The traditional hypothesis of isentropic contraction, typically considered for the boundary resolution, is replaced by an entropy corrected method of characteristics (MOC) in order to be consistent with a non-homentropic formulation. The boundary resolution method is designed independently of the quasi-steady restriction models which allows obtaining a greater modeling flexibility when compared with traditional methods. An experimental validation at unsteady conditions is presented using different restriction quasi-steady models to illustrate the effectiveness of the proposed boundary resolution method in terms of predictability as well as flexibility.
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Exhaust Manifold Pressure Estimation Diesel Equipped with a VGT Turbocharger

GIPSA Lab - Renault SAS-Felipe Castillo
Renault SAS-Vincent Talon
Published 2013-04-08 by SAE International in United States
This paper develops an exhaust manifold pressure estimation method for a Diesel engine equipped with a variable geometry turbine (VGT) turbocharger. Extrapolated VGT data-maps are used directly for the estimation of the exhaust pressure using a non-iterative Newton-Raphson based method suitable for real-time applications. This approach can give more accurate estimations than traditional methods because it takes into account the turbine speed effect on the turbine mass flow rate. All this without increasing the calculation load significantly. The proposed exhaust manifold estimation can be used to relieve the exhaust manifold pressure physical sensor during engine operating conditions where its reliability is low. The estimator is evaluated in transient with two different engine cycles using a engine model validated in a benchmark as a reference.
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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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Validation and Application of a New 0D Flame/Wall Interaction Sub Model for SI Engines

SAE International Journal of Engines

GIPSA Lab-Olivier Sename, Emmanuel Witrant
PRISME-Pascal Higelin, Christian Caillol
  • Journal Article
  • 2011-01-1893
Published 2011-08-30 by SAE International in United States
To improve the prediction of the combustion processes in spark ignition engines, a 0D flame/wall interaction submodel has been developed. A two-zones combustion model is implemented and the designed submodel for the flame/wall interaction is included. The flame/wall interaction phenomenon is conceived as a dimensionless function multiplying the burning rate equation. The submodel considers the cylinder shape and the flame surface that spreads inside the combustion chamber. The designed function represents the influence of the cylinder walls while the flame surface propagates across the cylinder. To determine the validity of the combustion model and the flame/wall interaction submodel, the system was tested using the available measurements on a 2 liter SI engine. The model was validated by comparing simulated cylinder pressure and energy release rate with measurements. A good agreement between the implemented model and the measurements was obtained.
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