The New 2.2 All-Aluminum Alfa Romeo Diesel Engine

Authors

Dipl.-Ing. M. G. Lisbona, Dipl.-Ing. E. Bonamassa, Dipl.-Ing. S. Cereda, Alfa Romeo, Modena

Year

2016

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 799

Summary

The Alfa Romeo Giulia during the ‘60s and ’70s demonstrated its character of very fast and sporty car, with very powerful engines and a rear-wheel-drive architecture designed in order to give the best handling in all driving conditions. The new Giulia is a rear wheel drive, with the same layout from its ancestor. When the Alfa Romeo engineers evaluated the existing Diesel engine characteristics, they discovered they were not suitable for the application: the cast iron block makes the powertrain too heavy to ensure a good balance between front and rear axle and it was necessary to start designing a completely new engine. The existing 2.2L 200 HP unit was the starting point for this project: its fluid- and thermo-dynamic behavior gives an extremely good efficiency and a very high power output, still open to further developments. Around this cylinder unit, a completely new all-aluminum structure was designed, characterized by a cylinder block and bedplate architecture. The application of aluminum to a high specific power diesel engine was surely challenging. Because of the very high combustion peak pressure (around 200 bar), it requested significant development work for both foundry and machining processes, being supported by the most sophisticated CAE analysis tools and simulation. Targeting to meet the best NVH behavior, balancer shaft system was completely redesigned adopting two balancer shafts driven by a gear train on flywheel side to reduce shaft-rolling vibrations and integrating shaft seats into cylinder block to give a very high stiffness to the structure.