Enrico Pautasso

This paper presents the development of a fully-physical 0D Fast Running engine Model (FRM) and its deployment on a HiL system for ECU testing. The FRM was built starting from the detailed 1D engine model which was developed within design department for performance prediction. In this way, the best engine modeling capabilities within the company can be fully exploited to maximize productivity.
The detailed 1D GT-POWER® model was reduced to a 0D FRM, by lumping its volumes and simplifying the… Visualizza altro

This paper presents the development of a fully-physical 0D Fast Running engine Model (FRM) and its deployment on a HiL system for ECU testing. The FRM was built starting from the detailed 1D engine model which was developed within design department for performance prediction. In this way, the best engine modeling capabilities within the company can be fully exploited to maximize productivity.
The detailed 1D GT-POWER® model was reduced to a 0D FRM, by lumping its volumes and simplifying the flow-path so that larger time-steps could be taken by the fluid-dynamics solver. This resulted in a dramatic reduction in computational requirements, which enabled Real-Time (RT) simulations. The FRM was then integrated into a Simulink-based architecture, comprehending a transmission, drive-train and vehicle model and all the I/O connections to the ECU. This MATLAB/Simulink® (M/S) model, encapsulating the engine FRM, was then deployed on a dSPACE® HiL machine for ECU testing.
The 0D FRM, being a physically-based model, retained the predictivity of a traditional 1D model and responded to changes in the ECU calibration parameters such as injection energizing time, mass flow rate set points, boost pressure levels. Moreover, it was possible to update at any time the FRM according to hardware (e.g. turbocharger maps, valve timings) or calibration changes that meanwhile occurred to the real engine in the course of the development process, unlike traditional map-based plant models in M/S, which required experimental data to be collected in order to populate again the look-up tables. The complete model was tested on several steady state operating conditions as well as on the NEDC driving cycle (including Start & Stop and NOx Trap regeneration logics), giving more than satisfactory results. Meno dettagli

In this paper a novel approach to mimic through numerical simulation Cycle-to-Cycle Variations (CCV) of the combustion process of Spark Ignition (SI) engines is described. The proposed methodology allows to reproduce the variability in combustion which is responsible for knock occurrence and thus to replicate the stochastic behavior of this abnormal combustion phenomenon.

On the basis of the analysis of a comprehensive database of experimental data collected on a typical European… Visualizza altro

In this paper a novel approach to mimic through numerical simulation Cycle-to-Cycle Variations (CCV) of the combustion process of Spark Ignition (SI) engines is described. The proposed methodology allows to reproduce the variability in combustion which is responsible for knock occurrence and thus to replicate the stochastic behavior of this abnormal combustion phenomenon.

On the basis of the analysis of a comprehensive database of experimental data collected on a typical European downsized and turbocharged SI engine, the proposed approach was demonstrated to be capable to replicate in the simulation process the same percentage of knocking cycles experimentally measured in light-knock conditions, after a proper calibration of the Kinetics-Fit (KF), a new phenomenological knock model which was recently developed by Gamma Technologies.

Finally, the capability of the proposed methodology, coupled with the usage of the KF knock model, to correctly identify the Knock Limited Spark Advance (KLSA) on the basis both of the CCV-replicating model and of a more traditional average-cycle simulation was assessed over a wide range of different operating conditions, thus confirming its reliability and robustness. Meno dettagli

In this paper a novel approach to mimic through numerical simulation Cycle-to-Cycle (CCV) Variations of the combustion process of Spark Ignition (SI) engines is described. The proposed methodology allows to reproduce the variability in combustion which is responsible for knock occurrence and thus to replicate the stochastic behaviour of this abnormal combustion phenomenon.
On the basis of the analysis of a comprehensive database of experimental data collected on a typical European downsized… Visualizza altro

In this paper a novel approach to mimic through numerical simulation Cycle-to-Cycle (CCV) Variations of the combustion process of Spark Ignition (SI) engines is described. The proposed methodology allows to reproduce the variability in combustion which is responsible for knock occurrence and thus to replicate the stochastic behaviour of this abnormal combustion phenomenon.
On the basis of the analysis of a comprehensive database of experimental data collected on a typical European downsized and turbocharged SI engine, the proposed approach was demonstrated to be capable to replicate in the simulation process the same percentage of knocking cycles experimentally measured in light-knock conditions, after a proper calibration of the Kinetics-Fit (KF), a new phenomenological knock model which was recently developed by Gamma Technologies.
Finally, the capability of the proposed methodology, coupled with the usage of the KF knock model, to correctly identify the Knock Limited Spark Advance (KLSA) on the basis of the CCV-replicating model was assessed over a wide range of different operating conditions, thus confirming its reliability and robustness.
Meno dettagli

In order to meet the very stringent emissions standards, particular attention has to be provided to ensure quick catalyst light-off. One of the strategies being considered to reduce light-off time is to place an electrically heated catalyst upstream of the main catalyst. In this regard, a model for an electrically heated catalyst has been developed. The model uses a highly efficient advanced adaptive (time and space) numerical scheme including a quasi-steady assumption which states that spatial… Visualizza altro

In order to meet the very stringent emissions standards, particular attention has to be provided to ensure quick catalyst light-off. One of the strategies being considered to reduce light-off time is to place an electrically heated catalyst upstream of the main catalyst. In this regard, a model for an electrically heated catalyst has been developed. The model uses a highly efficient advanced adaptive (time and space) numerical scheme including a quasi-steady assumption which states that spatial changes are much greater than the temporal ones. The model has been validated using literature data for vehicle emissions tests and catalyst bed temperatures during cold start. This methodology is then applied to an aftertreatment system model comprised of an electrically heated catalyst upstream of a DOC, DPF, and SCR in series to investigate the effect of overall aftertreatment system efficiency during a New European Drive Cycle (NEDC). Finally, the aftertreatment system model is integrated with engine and vehicle models in order to study the trade-offs of tailpipe emissions vs. fuel penalty during an NEDC. Meno dettagli

Different optimization strategies for the optimization of the calibration of a turbocharged GDI engine through numerical simulation were analyzed, aiming to evaluate the opportunities offered by direct optimization techniques.

A one-dimensional fluid dynamic engine model was used to predict engine performance, taking into account knock and exhaust temperature constraints.

Air fuel ratio, spark advance, boost pressure and cam phasing were optimized by means of different… Visualizza altro

Different optimization strategies for the optimization of the calibration of a turbocharged GDI engine through numerical simulation were analyzed, aiming to evaluate the opportunities offered by direct optimization techniques.

A one-dimensional fluid dynamic engine model was used to predict engine performance, taking into account knock and exhaust temperature constraints.

Air fuel ratio, spark advance, boost pressure and cam phasing were optimized by means of different optimization strategies, including direct search as well as numerical methods.

Both full load (with maximum bmep targets) and part load (with minimum bsfc targets) were considered.

The potential for remarkable improvements (up to 10% bmep increase at full load and 8 g/kWh bsfc decrease at part load) in comparison with the baseline engine calibration was highlighted, and a ranking between different optimization methods was obtained, based on the requested computational efforts and on their capabilities to handle constrained optimization problems. Meno dettagli

In this study, a new EGR control technique, based on the estimate of the oxygen concentration in the intake manifold, was firstly investigated through numerical simulation and then experimentally tested, both under steady state and transient conditions.

The robustness of the new control technique was also tested and compared with that of the conventional EGR control technique by means of both numerical simulation and experimental tests.

Substantial reductions of the NOx emissions… Visualizza altro

In this study, a new EGR control technique, based on the estimate of the oxygen concentration in the intake manifold, was firstly investigated through numerical simulation and then experimentally tested, both under steady state and transient conditions.

The robustness of the new control technique was also tested and compared with that of the conventional EGR control technique by means of both numerical simulation and experimental tests.

Substantial reductions of the NOx emissions under transient operating conditions were achieved, and useful knowledge for controlling the EGR flow rate more accurately was obtained. Meno dettagli

A DoE analysis was carried out to investigate the effects of the compression ratio, injection timing, injector nozzle hole size and number on performance and emissions in a diesel marine engine, aiming to find out the optimal combination between all the abovementioned parameters.

The study was performed on a six cylinder in line, 100 liter total displacement, diesel marine engine, by means of a 1-D engine simulation fluid-dynamic code, coupled with a multi-zone combustion model for oxide… Visualizza altro

A DoE analysis was carried out to investigate the effects of the compression ratio, injection timing, injector nozzle hole size and number on performance and emissions in a diesel marine engine, aiming to find out the optimal combination between all the abovementioned parameters.

The study was performed on a six cylinder in line, 100 liter total displacement, diesel marine engine, by means of a 1-D engine simulation fluid-dynamic code, coupled with a multi-zone combustion model for oxide of nitrogen (NOx) and particulate (PM) prediction.

A preliminary detailed validation process, based on an extensive experimental data set, was carried out on the engine model concerning, in particular, the predicted heat release rate, the in-cylinder pressure trace and NOx emissions for several operating points of a propeller load curve.

Afterward a full factorial Design of Experiments (DoE) analysis was carried out in order to find out the optimal combination between compression ratio, injection timing, injector nozzle hole size and number aiming to reach the lowest brake specific fuel consumption value while complying with NOx emissions and peak firing pressures constraints. Meno dettagli

The potential of an electric assisted turbocharger for a heavy-duty diesel engine has been analyzed in this work, in order to evaluate the turbo-lag reductions and the fuel consumption savings that could be obtained in an urban bus for different operating conditions.

The aim of the research project was to replace the current variable geometry turbine with a fixed geometry turbine, connecting an electric machine which can be operated both as an electric motor and as an electric generator… Visualizza altro

The potential of an electric assisted turbocharger for a heavy-duty diesel engine has been analyzed in this work, in order to evaluate the turbo-lag reductions and the fuel consumption savings that could be obtained in an urban bus for different operating conditions.

The aim of the research project was to replace the current variable geometry turbine with a fixed geometry turbine, connecting an electric machine which can be operated both as an electric motor and as an electric generator to the turbo shaft. The electric motor can be used to speed up the turbocharger during the acceleration transients and reduce the turbo-lag, while the generator can be used to recover the excess exhaust energy when the engine is operated near the rated speed, in order to produce electrical power that can be used to drive engine auxiliaries. In this way the engine efficiency can be improved and a kind of “electric turbocompounding” can be obtained.

However, the potential of this kind of system depends to a great extent on the driving cycle (i.e. the “regeneration” periods, when the electric machine operates as a generator, should be long enough to produce and store the energy that is required to speed-up the turbocharger during the acceleration transients of the internal combustion engine).

The potential of this “Electric Exhaust Gas Turbocharging” for a six cylinder, 8 liter displacement, HD diesel engine has therefore been analyzed in this work, through a 1-D engine simulation fluid dynamic code, coupled to a driveline and vehicle model. Fuel consumption reductions of 6 to 1 % were demonstrated, depending on the driving cycle. Meno dettagli