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This paper considers a model based turbocharger control strategy for a Diesel engine fitted with a variable geometry turbocharger and two EGR circuits. Compared with controllers based on lookup tables, the model based control law is very successful specially that it adapts with the physical behavior of the system studied. Is this paper we propose to affine this strategy and make it more robust, specially for modeling errors and sensors fault, to ensure an accurate regulation for the intake manifold pressure. Therefore, we observe that the turbine efficiency, which is used in the model based control law, is a key variable for this purpose. Thus, the main contribution of this paper is to combine the model based controller with an estimator of the turbine efficiency. By adapting online the efficiency map, all the modeling errors in the control law will be significantly reduced, particularly at steady state with benefits also provided during transients.

This paper proposes a method to detect an intake manifold leakage for a Diesel engine with a dual loop EGR system. The intake manifold leak has a strong impact on the engine performances by changing the intake manifold burned gas ratio. This fault is analyzed according to the control structure used and also according to the EGR operating mode. The paper proposes a diagnosis algorithm to detect the intake manifold leak in sequential or simultaneous use of the two EGR paths. The sensors considered are the mass air flow meter, the intake manifold pressure sensor, the exhaust equivalence ratio sensor and the differential pressure sensor (across the HP EGR valve). The diagnosis is based on a criteria that uses the redundancy between these sensors and air system models or estimators. The diagnosis threshold depends on the engine operating conditions as well as the sensor or model dispersions.

A major issue in the development of the future engines (diesel or gasoline) lies in the architecture and the control of the air intake system. In this context many setups are envisaged, and in particular the turbocharging systems are becoming more and more complex: variable geometry turbines, double stage turbochargers, variable geometry compressors… For these new architectures, the engine control strategies need to be modified in order to address the specific issues related either to the new system in itself or to its integration in the global engine. Renault and IFP have studied together, from a control point of view, the integration of a double stage turbocharger in a diesel engine. This paper presents the works undertaken during this study. The structure of the paper follows the different stages of the project.

Improving the simulation support in engine development projects is a very attractive way to reduce cost and duration of such projects while increasing the deliverable quality. Thanks to advanced models and specific know-how, this paper presents a new step which consists in the use of simulation as a virtual engine bench for control design when the real engine is not yet available. In a first part, the goals and requirements of such a simulation approach are described. Then, the specific case of a two-stage turbocharger Diesel engine application from an IFP-RENAULT control design study is presented. At first, the virtual bench design is detailed from a methodological point of view. The engine simulator development and its use as a virtual control bench are then described. The control strategies design is presented, but also the anticipation of potential limitations such as inadequate turbocharger behavior or system failure detection management.