A new G16NB gas engine for generator use adopting a two-stage turbocharging system was
developed for the improvement of electrical efficiency and output. Two-stage turbocharging, intake
valve close timing and expansion ratio optimization, as well as an increased peak firing pressure,
were adopted to achieve the development target of 10% (4% points) or higher efficiency
improvement. The test engine operated by city gas (13A) displayed the results below: (1)
Turbocharger efficiency was improved by 14% points compared with that of conventional models.
In addition, the pressure ratio of compressor was increased by 1.5 contrasted with that of
conventional models at the rated output. (2) The electrical efficiency of the engine was increased
by 4% points, and attained the world's top level efficiency of 44.7% or higher. Additionally, the
break mean effective pressure (BMEP) was raised by 0.5 MPa in contrast to that of the current
model.
