High performance computing and analysis-led development of high efficiency dilute opposed piston gasoline engine

Pinnacle is developing multi-cylinder 1.2 L gasoline engine for automotive applications using high performance computing (HPC) and analysis methods. Pinnacle and Oak Ridge National Laboratory executed large-scale multi-dimensional combustion analyses at the Oak Ridge Leadership Computing Facility to thoroughly explore the design space. These HPC-led investigations show high fuel efficiency (~46% gross indicated efficiency) may be achieved by operating with extremely high charge dilution levels of exhaust gas recirculation (EGR) at a light load key drive cycle condition (2000 RPM, 3 bar BMEP), while simultaneously attaining high levels of fuel conversion efficiency and low NOx emissions. In this extremely dilute environment, the flame propagation event is supported by turbulence and bulk in-cylinder charge motion brought about by modulation of inlet port flow. This arrangement produces a load and speed adjustable amalgamation of swirl and counterrotating tumble which provides the turbulence required to support stable low-temperature combustion (LTC). At higher load conditions, the engine may operate at more traditional combustion modes to generate competitive power. In this paper, the numerical results from these HPC simulations are presented. Further HPC simulations and test validations are underway and will be reported in future publications.