Optimized matching process for gasoline engines for Eu6c/EU7

Turbocharging has become a key technology in new engines both for gasoline and diesel. The process aiming to adapt and optimize the turbocharger behavior to the different engine working points is known as turbo-matching. For gasoline engines, the matching has been less crucial thanks a large use of the scavenging process. For Eu6c/EU7 and possible RDE regulation, as scavenging could be restricted, the turbo-matching needs to be even more accurate. Authors have intensively during last years worked jointly to optimize the turbocharger matching process. This paper will present the main improvement achieved.

Authors will start from an explanation of the problems faced by an OEM in the use of a supplier turbocharger map. From this issue the paper will firstly explain the impact in the measurement of the different turbocharger test bench set-ups. To reduce the discrepancies between different characterizations, the effort has been focused on the definition of a standard mapping procedure together with the establishment of a GT Power model which could support the analyses.
The industrialization of CMT Motores Térmicos extrapolation model allows the authors characterizing the turbocharger in an early phase of the engine development process. This process allows characterizing the machine under unsteady conditions and under different thermal balances. A comparison between quasi-adiabatic and adiabatic mapping procedure is given in order to characterize mechanical efficiency of the turbo-machine in low rotational conditions.

In conclusion the authors will present their outlook and perspectives focused on the improvement of the extrapolation models and of the data base in order to fasten the matching process.