D2SE-Decarbonization & depollution of energy systems

Research areas

Gas Dynamics and Cylinder Filling

This line of research consists of studying any physical phenomenon that affects the air filling of the cylinders or that interacts with the unsteady compressible flows within the intake or exhaust circuits. Some examples of systems studied: active system of filling, interaction waves-supercharging, thermo-electric generator, ...
This research enables :
- To understand a physical phenomenon, to optimize the operation of an engine - To define and then validate new concepts (prototypes) of optimization of the filling
- To develop new simulation tools with the best compromise between accuracy and simulation time

The pressure waves generated by the opening and closing of the valves intervene in the air filling of the cylinders. These phenomena are therefore directly related to the efficiency of the internal combustion engine. These unsteady and compressible flows can be studied one-dimensionally by modeling each of the singularities (engine or geometric discontinuities) using a CFD calculation code and / or experimental results.

Another approach consists in using the frequency signature of a complete intake and / or exhaust circuit taking into account the flow rate of the engine. This signature makes it possible to model the circuits by a model with concentrated parameters which has the main advantage of being faster in computation time than a more conventional one-dimensional method. Indeed, a direct link is made between the pressure upstream of the valves and the flow through a transfer function (or matrix), which makes it possible to reduce the number of equations. The models thus developed are then integrated into a code for simulating the complete operation of an internal combustion engine.

For the experimental part, shock tube benches can be used to characterize the physical phenomena or for the validation of the developed models. The final validation is carried out on the basis of complete engine tests.

Manager: David CHALET (david%2Echalet%40ec-nantes%2Efr)

Turbomachinery

Turbocharging of internal combustion engines is a widely used technique, whether in the field of industrial engines or in the automobile. This technique evolves rapidly with the arrival of more and more precise systems to more finely adapt the operation of the turbocharger to that of the engine: variable geometry on turbine and compressor side, twinscroll, double stage supercharging series or sequential. This evolution leads to more modeling needs to make more precise and more predictive the software to aid in the design of propulsion sets.








In this context, the team has been working since its creation on the development of new turbochargers modeling, based on experiments carried out in the laboratory on turbocharger test benches or engine test benches.

Manager: Pascal CHESSÉ (pascal%2Echesse%40ec-nantes%2Efr)

Combustion in engines and polluting emissions

The general objective is to understand the combustion process and the accompanying pollutant formation.

This analysis can then be used to reduce emissions at source, by improving existing decontamination techniques (EGR, ..), by proposing innovative techniques (intake water injection, water-diesel emulsion, etc.) or new combustion modes (Stoichiometric diesel combustion, PCCI, RCCI, ...).

Combustion characterization is also used to develop more or less detailed phenomenological models (0D and 1D models for cycle-scale modeling, mean models for MVEM applications). These models can describe the heat release from combustion and, where appropriate, local disparities in wealth and temperature as well as the production of polluting species. They are intended for use in simulation software, as tools to assist in the design or development of engines.

Cylindrical phenomena related to combustion are also addressed: injection, gas exchange for the renewal of the load, heat transfer to the walls, efficiency of energy conversions and distribution of losses.

Manager: Xavier TAUZIA (xavier%2Etauzia%40ec-nantes%2Efr)

System Interaction and Hybridization

This new research focus of the research group concerns the modeling and simulation of alternative propulsion methods (hybrid, energy recovery, new fuel, etc.) with a view to their optimization by including all the associated problems (energy flow, Thermo-management, ...).

This simulation work applicable both to the land and maritime domains is based on the system approach. Experimental studies will soon be implemented to complement this approach and will rely, in particular, on the dynamics laboratory test bench of the laboratory.

Manager: Jean-François HETET (Jean-Francois%2EHetet%40ec-nantes%2Efr)

Main experimental means of the group

Engine test benches

The engine test benches have conventional instrumentation such as engine speed, pressure, temperature, cylinder pressure, but also fuel balance and pollutants measurement systems, to quantify engine emissions and the quality of combustion.





 

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Turbocharger test benches

These benches are used to test and characterize turbochargers in a controlled environment, outside the influence of the engine.


 

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Vehicle test bench

This test bench allows a complete 4-wheel drive vehicle to be tested in dynamic operation. It can be used to replace road tests with reproducible tests in a controlled environment. It can test vehicles with a power output of 260 kW per axle.

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• Renault-Siemens (Simulation, control and development of internal combustion engines and innovative propulsion systems)
• Mann + Hummel (Innovative intake systems and thermo-management)
• Read more about the "Industrial chairs"