MAN tests two-stage turbocharger

Under its Ecocharge project MAN is developing a two-stage turbocharger for use with both gas and HFO-fuelled engines. The prototype was tested on a MAN 12V35/44 gas engine.

MAN said that the combination of a TCR20 at the low-pressure stage and a TCX17 at the high-pressure stage offered improved scavenging air pressure (pushing exhaust fumes out of the engine between strokes) of five to 10 bars. It also improves turbocharging efficiency, with the intercooler between the two stages reducing the energy needed to compress intake air.

Greater turbocharging efficiency also reduces NOx emissions through the Miller cycle, while scavenging efficiencies make the engine more fuel efficient. MAN added that the higher power-density generated by the Ecocharge technology also enables ship operators to either boost an engine’s power output or reduce the size of engine needed for the same output.

The company noted: “MAN Diesel & Turbo sees great potential in two-stage turbocharged engines, which can be seen in the spate of recent orders for such solutions. Two-stage turbocharging differs significantly from single-stage turbocharging in that it also copes with the demands of a high-pressure stage. The MAN TCX turbocharger has been especially developed for two-stage turbocharger applications.”