ABB Turbocharging has introduced its Power2 two-stage turbocharging system, developed to help meet NOx emissions limits for IMO Tier 3 regulations.
The systems under development comprise two turbochargers of different, tuned frame sizes with the larger turbocharger upstream of the smaller unit, said ABB. They are connected in tandem on the compressor side via an intermediate air cooler. The company said that cooling the compressed air from the first turbocharger reduces the work of the second turbocharger, allowing it to be more compact.
The system produces pressure ratios around 8, which ABB said results in double-digit NOx reductions on four-stroke medium-speed diesel engines.
Additionally, ABB is furthering its work on the Valve Control Management (VCM) system for large four-stroke engines. This work is jointly developed with partner INA Schaeffler, a manufacturer of automotive engine components and systems. These developments were implemented to assist engine builders to attain the Miller Cycles needed to alleviate the constraints in the search for lower NOx emissions without penalties on the fuel efficiency side, said ABB.