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The design and the supervision of hybrid electric vehicles (HEV) are strongly coupled. The mutual influence between the optimal components sizing and the optimal operating points choice makes the problem complex. This was previously exposed in literature for spark ignition (SI) HEV. In this paper, we address the same issue for diesel HEV. In this case, the energy management strategy must take nitrogen oxides (NOx) emissions into account in addition to fuel consumption. This paper presents an optimal supervision strategy and its impact on the electric components sizing. The energy management strategy is based on the equivalent consumption minimization strategy (ECMS) using Pontryagin's minimum principle. It allows an adjustable trade-off between NOx and fuel consumption to be minimized. It was validated experimentally with a hardware-in-the-loop test bed.

The present paper deals with the activities and the results achieved under a cooperative research project between IFP, D2T, LMS, G2Elab and Renault focused on Hardware-in-the-Loop (HIL) applications to hybrid power-trains conception and assessment. The main goal of this study is the evaluation of hybrid propulsion concepts and the benefits of different degrees of hybridization in a flexible architecture, by using a chain of simulation platforms: from the co-simulation to the high-dynamic engine-in-the-loop test bed, through a virtual version of the last one. The activity assessed the potentialities in terms of fuel consumption reduction and the challenges in terms of pollutants emissions of micro and full-hybrid application for light-duty vehicle based on gasoline engine: over several road load cycles as NEDC, FTP72, ARTEMIS.

The powertrain simulation tools are nowadays an efficient support to optimize cost and duration of the whole engine technological developments. They can deliver optimized simulator versions for various targets such as system understanding, design investigation, non-measurable value access or virtual bench use for control and calibration. Under the condition of an accurate modelling and simulation know-how to take into account the simulator using constraints, the simulation can become an undisputable support for powertrain design as the test bed already is. The goal of this paper is to present the large range of the powertrain simulation capabilities for the specific application of a downsized turbocharged GDI engine with twin VVT embedded in a concept car. The modelling framework is first presented and different items are laid-out. A first part is dedicated to the engine air path and in particular to the modelling of gas exchange phenomena such as back-flow.

This paper presents the development of torque-based engine control strategies for a downsized SI engine, from simulation design to final validation on a demonstration car. One main issue to reach performance, fuel consumption and pollutant emission demands is in-cylinder mass observation and control. A simulation-based approach is first presented to design accurate observers from a reference simulator. In this study, a multivariable and non-linear control has been developed and focused on in-cylinder mass trajectories. It has been tested on a real time Software-In-the-Loop platform before a complete validation and calibration on the test bed. Finally, the complete torque-based engine control has been successfully integrated on the vehicle.

Observation problems have been garnering increasing attention in recent years. They can be seen as the estimation of a periodic output dynamics driven by periodic inputs. At various level of modelling, automotive engine dynamics can be considered as a linear periodic system mechanically coordinated through the revolution of the crankshaft. In this paper, two practical examples are addressed. The first example is the inversion of sensor dynamics. A classical way of modelling such a sensor is a first order dynamics with periodic excitations which can be, depending on the application, the intake pressure, the intake temperature, the exhaust pressure, the Air Fuel Ratio, or the Mass Air Flow. The second example is the estimation of the engine speed next to the cylinder using as only sensor the easily available instantaneous crankshaft angle speed at the end of the connecting rod.

In the context of increasingly stringent pollution norms, reduced engine emissions are a great challenge for compressed ignition engines. After-treatment solutions are expensive and very complex to implement, while the NOx/PM trade-off is difficult to optimise for conventional Diesel engines. Therefore, in-cylinder pollutant production limitation by the HPC combustion mode (Highly Premixed Combustion) - including Homogeneous Charge Compression Ignition (HCCI) - represents one of the most promising ways for new generation of CI engine. For this combustion technology, control based on torque estimation is crucial: the objectives are to accurately control the cylinder-individual fuel injected mass and to adapt the fuel injection parameters to the in-cylinder conditions (fresh air and burned gas masses and temperature).

In this paper, we address the problem of air path variables estimation for an HCCI engine. Two observers are proposed. Both rely on physical assumptions on the combustion, but use different sensors. After proving convergence in the two cases, we carry out comparisons based on simulation results. We stress the impact of two particular additional sensors on obtained performance: fresh air and EGR temperature probes.

In the context of modern engine control, one important variable is the individual Air Fuel Ratio (AFR) which is a good representation of the produced torque. It results from various inputs such as injected quantities, boost pressure, and the exhaust gas recirculation (EGR) rate. Further, for forthcoming HCCI engines and regeneration filters (Particulate filters, DeNOx), even slight AFR unbalance between the cylinders can have dramatic consequences and induce important noise, possible stall and higher emissions. Classically, in Spark Ignition engine, overall AFR is directly controlled with the injection system. In this approach, all cylinders share the same closed-loop input signal based on the single λ-sensor (normalized Fuel-Air Ratio measurement, it can be rewritten with AFR as they have the same injection set-point.

This paper presents 1D engine simulation used for engine control strategy optimization for a twin-scroll turbocharged gasoline direct injection 2.0 L engine with twin camphaser. The results show good agreement of the engine model behavior with testbed acquisitions for a large amount of steady state set points and under transient operating conditions. The presented method demonstrates that a 1D engine code represents a useful and efficient tool during all steps of the engine control development process from design to real-time for such an advanced engine technology.

Nowadays, (engine) downsizing using turbocharging appears as a major way for reducing fuel consumption. With this aim in view, the air actuators (throttle, Turbo WasteGate) control is needed for an efficient engine torque control especially to reduce pumping losses and to increase efficiency. This work proposes Nonlinear Model Predictive Control (NMPC) of the air actuators for turbocharged SI engines where the predictions are achieved by a neural model. The results obtained from a test bench of a Smart MCC engine show the real time applicability of the proposed method based on on-line linearization and the good control performances (good tracking, no overshoot) for various engine speeds.

On diesel engines, a discrepancy between the air fuel ratio (AFR) of the cylinders can lead to a decrease of full load performances, an increase of pollutant and noise emissions and has an effect on the aftertreatment efficiency. A cylinder individual AFR estimator has been developed using Kalman filter techniques. This estimator is based on a physical model of the exhaust, and intended to be implemented in an engine management system. The time delay of the exhaust system, including the sensor, can be identified online. When applied on testbed acquisitions, the estimator gives good results over the whole operating range of the engine.

For studying simultaneously and early in the development process the effects of engine design parameters and of control strategies on HC emissions, a methodology has been set up to reproduce on a gasoline single-cylinder engine the beginning of MVEG cycle. This methodology uses different fuels and analysis tools to assess the HC sources. Oil and water are heated to follow the thermal behavior of a multi cylinder engine. A fast prototyping system is used to control the engine. Special attention has been paid to take into account the acoustic effect on the air feeding. The main tendencies observed in stabilized conditions are similar to transient test conditions with GDI engine. Wall wetting appears as the main source of HC emission in case of direct injection. Transient effects are especially sensitive during cold conditions.

Torque balancing for diesel engines is important to eliminate generated vibrations and to correct injected quantity disparities between cylinders. The vibration phenomenon is important at low engine speed and at idling. To estimate torque production from each cylinders, the instantaneous engine speed from the crankshaft is used. Currently, an engine speed measurement every 45° crank angle is sufficient to estimate torque balance and to correct it in an adaptive manner by controlling the mass injected into each cylinder. The contribution of this article is to propose a new approach of estimation of the indicated torque of a DI engine based on a nonstationary linear model of the system. On this model, we design a linear observer to estimate the indicated torque produced by each cylinder. In order to test it, this model has been implemented on a HiL platform and tested on simulation and with experimental data.