High BMEP engines (approximately 250 PSI) have been investigated for a number of years in a laboratory environment. The NTC-475 has been brought to production as an automotive engine. This engine delivers a power to weight ratio of 577 lb/HP. The engine operates at levels of 209.5 PSI at rated and 251.5 PSI at torque peak (20% torque rise).
The application of series boost turbochargers provides interesting boost characteristics. The independent running shafts provide a high level of flexibility to cover the engine speed range and high altitude operation. The engine has been in commercial production since April of 1981.
The emphasis of this paper will be on the turbocharging system, aftercooling, injection timing, and lengthy field test program.