LESSCCV

Large-Eddy and System Simulation to predict Cyclic Combustion Variability in gasoline engines

 Partecipanti

Mappa

 Word cloud

Esplora la "nuvola delle parole (Word Cloud) per avere un'idea di massima del progetto.

 Obiettivo del progetto (Objective)

'The objective of LESSCCV is to exploit the recent possibilities of engine computational fluid dynamics (CFD) tools to fundamentally improve the understanding of cyclic combustion variability (CCV) in gasoline engines under real operating conditions, and to provide adequate modelling. Multi-scale CFD tools, able to study in detail the sources of CCV in full engines, will be developed. These tools will be achieved by coupling 1D-CFD codes, describing the flow in the intake and exhaust lines as well as in the fuel injection system (FIS), with 3D-CFD codes using the innovative Large-Eddy Simulation (LES) technique, which can accurately reproduce the cycle resolved flow inside the combustion chamber. The resulting multi-scale tools will then be applied to study the sources and effects of CCV in different gasoline engines. Work will also concern studying in more detail the effects of local factors, as early flame kernel growth at the spark plug and the interaction between the flow in the FIS and the fuel spray in a vessel, on CCV. The resulting improved understanding of CCV in gasoline engines will be capitalised in the form of models able to reproduce the characteristics and effects of CCV in multi-cycle 1D-CFD simulations of operating points subject to cyclic variability. Finally, the improved three industrial 1D-CFD codes incorporating these models will be applied in case studies aimed at demonstrating the benefits to be expected from a better prediction of CCV in terms of CO2 and pollutant emissions under real driving conditions. The LESSCCV partnership brings together 3 major European engine simulation software vendors, 2 research centres and 3 Universities from 7 European countries, all internationally recognised for their expertise in engines and simulation.'

Introduzione (Teaser)

The development of combustion engines is under increasingly stringent constraints with regard to fuel efficiency and emissions. Advanced modelling tools developed with EU support will help meet performance objectives starting from the early phases of design.

Descrizione progetto (Article)

Several novel engines have the potential to alleviate problems associated with conventional combustion. However, all of these technologies are plagued by cycle-to-cycle or cyclic combustion variability (CCV) that limits their performance. Detailed knowledge of the factors and operating regimes leading to CCV for specific engine types was previously lacking. Scientists working on the EU-funded LESSCCV project decided to fill the gap by exploiting recent advances in complex design tools using computational fluid dynamics (CFD).

The consortium developed multi-scale CFD tools capable of simulating the entire engine, including the combustion chamber, as well as intake and exhaust ducts. The tools couple one-dimensional (1D) CFD codes describing flow in the intake and exhaust lines with 3D CFD codes (large eddy simulations (LESs)). This will account for turbulent interactions and combustion inside the combustion chamber or cylinder.

Tools were applied to the study of CCV in three types of gasoline engine, generating a wealth of complex data for further analysis. Scientists were able to validate the model by comparing outcomes with experimental data and identified the main causes of CCV in each of the engine types. Enhanced understanding of CCV led to the formulation of novel and less computationally-intensive (reduced CCV) models equally capable of predicting behaviours. Case studies on engines and vehicles highlighted ways in which novel designs could reduce CCV and increase efficiency.

Exploitation of LESSCCV tools and results is expected to contribute significantly to short-term goals of more efficient and greener combustion engines for the transport sector. The predictive design tools will not only reduce the environmental impact of transportation but also enhance the competitiveness of EU engine manufacturers.