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Burned gas recirculation is emerging as a promising technology to reduce fuel consumption without compromising performance in turbocharged spark ignited engines. This recirculation can be done internally through Internal Gas Residual (IGR) using Variable Valve Timing (VVT) or externally through classical Exhaust Gas Recirculation circuit (EGR). Both have a large impact on combustion. The purpose of the paper is to give clues to get the best compromise at moderate load between these two technologies in terms of fuel consumption. This experimental work was performed on a Gasoline Direct Injection (GDI) engine, 2.0L displacement, dual independent VVT, equipped with a Low Pressure, cooled and catalyzed EGR loop (LP EGR). The load region covers 6 to 10 bar Indicated Mean Effective Pressure (IMEP). EGR rates obtained vary between 0 and 15%. IGR variation is obtained by using the VVT in order to vary the valve overlap. IGR rates vary from 4 to 8%.

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.

HCCI or CAI engine technologies require an accurate combustion monitoring and control because there is no direct ignition trigger. The control of ignition is inherently more difficult than in standard internal combustion engines and needs additional sensors such as cylinder pressure to perform closed loop combustion control. In this paper we present a rapid prototyping platform dedicated to high frequency recording and processing. We illustrate the functionalities of the platform through an example of combustion parameters estimation from indirect measurement (knock sensor). The paper ends with a comparison of direct and indirect combustion parameters computation in real time for closed loop combustion control purpose. The presented results are carried out with knock data series recorded on HCCI and CAI engines.