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In this paper, a new physics-based model for the prediction of NOx emissions produced by diesel engines is presented. The aim of this work is to provide a reference model for the validation of control strategies and NOx estimators. The model describes the NOx production in the burned gas zone where the burned gas temperature sub-model is adapted to be generic and tunable. The model consists of three main sub-models for the estimation of the burned gas temperature, the concentration of the species in the burned gases and the NOx formation, respectively. A new model for estimating the burned gas temperature, known to have a strong impact on thermal NOx formation rate, is proposed. The model depends on the intake burned gas ratio and the combustion phasing computed from the cylinder pressure. This model has a limited number of calibration parameters identified so that NOx model output matches with experimental data measured in a four-cylinder, four-stroke, direct-injection diesel engine.

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.

Future pollutant emissions legislations are expected to be increasingly stringent. To reduce Nitrogen Oxides (NOx) emissions produced by Diesel engines, advanced combustion technologies - like Low Temperature Combustion (LTC) -, vehicle hybridization and NOx after-treatment systems - such as Selective Catalytic Reduction (SCR) systems - can be considered, leading to a growing demand for NOx models. In this paper, we present a state-of-art of the different existing NOx models, from the black-boxes to the three-dimensional Computational Fluid Dynamics (CFD) codes. A way to classify these models is proposed. The paper also introduces the current applications for each subgroup of models. Then, a black-box and two grey-box NOx models are studied regarding their accuracy and their sensitivity to model inputs. These models are validated for two Diesel engines on steady-state operating points as well as on transient operations. The semi-physical models accurately predict NOx emissions.

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.

Among the last years, environmental concerns have raised the interest for biofuels. Ethanol, blended with gasoline seems particularly suited for the operation of internal combustion engines, and has been in use for severals years in some countries. However, it has a strong impact on engine performance, which is emphasized on recent engine architectures, with downsizing through turbocharging and variable valve actuation. Taking all the benefits of ethanol-blended fuel thus requires an adaptation of the engine management system. This paper intends to assess the effect of gasoline-ethanol blending from this point of view, then to describe a mean-value model of a fuel-flexible turbocharged PFI-SI engine, which will serve as a basis for the development of control algorithms. The focus will be in this paper on ethanol content estimation in the blend, supported by both simulation and experimental results.

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.

We propose a model based control strategy to adapt the injection settings according to the air path dynamics on a Diesel HCCI engine. This approach complements existing airpath and fuelpath controllers, and aims at accurately controlling the start of combustion. For that purpose, start of injection is adjusted based on a Knock Integral Model and intake manifold conditions. Experimental results are presented, which stress the relevance of the approach.

Future engine control systems need suitable and accurate models for combustion. For this purpose, this paper presents a practical application of nonlinear autoregressive moving average polynomial models with exogenous inputs (NARMAX) technique to model pressure dynamics inside the cylinder of a direct injection compression ignition engine. Two models have been investigated taking two different sets of input variables. The first model only includes basic injection settings available from the electronic control unit. The second model uses the instantaneous crankshaft revolution speed as a main model input. Model parameter identification and validation are performed with experimental data obtained from a test engine equipped with a piezoelectric pressure sensor and with data computed from a thermodynamic-based engine cycle simulation code.

Constraints change as pollutant standards or embedded diagnosis demands require improvements in model accuracy and their suitability for control algorithm synthesis. From thermodynamic mathematical modelling to non-parametric models, a wide range of techniques has been investigated for the last thirty years involving both physicists and control engineers. The purpose of this paper is to give an overview of current modelling techniques oriented control analysis and design for compression ignition engines. Short examples illustrate each techniques and existing applications are considered. Comparison of various engine models exhibit the trend to include more physical knowledge inside model-based control design.