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Finney, Charles
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Cycle to Cycle Variation Study in a Dual Fuel Operated Engine

Convergent Science Inc.-Sameera Wijeyakulasuriya
GE, Global Research Center-ShyamSundar Pasunurthi, Ravichandra Jupudi, Sreenivasa Rao Gubba, Roy Primus, Adam Klingbeil
Published 2017-03-28 by SAE International in United States
The standard capability of engine experimental studies is that ensemble averaged quantities like in-cylinder pressure from multiple cycles and emissions are reported and the cycle to cycle variation (CCV) of indicated mean effective pressure (IMEP) is captured from many consecutive combustion cycles for each test condition. However, obtaining 3D spatial distribution of all the relevant quantities such as fuel-air mixing, temperature, turbulence levels and emissions from such experiments is a challenging task. Computational Fluid Dynamics (CFD) simulations of engine flow and combustion can be used effectively to visualize such 3D spatial distributions. A dual fuel engine is considered in the current study, with manifold injected natural gas (NG) and direct injected diesel pilot for ignition. Multiple engine cycles in 3D are simulated in series like in the experiments to investigate the potential of high fidelity RANS simulations coupled with detailed chemistry, to accurately predict the CCV.Cycle to cycle variation (CCV) is expected to be due to variabilities in operating and boundary conditions, in-cylinder stratification of diesel and natural gas fuels, variation in in-cylinder turbulence levels…
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Comparative Study of Hybrid Powertrains on Fuel Saving, Emissions, and Component Energy Loss in HD Trucks

SAE International Journal of Commercial Vehicles

Oak Ridge National Laboratory-Zhiming Gao, Charles Finney, Charles Daw, Tim J. LaClair, David Smith
  • Journal Article
  • 2014-01-2326
Published 2014-09-30 by SAE International in United States
Two hybrid powertrain configurations, including parallel and series hybrids, were simulated for fuel economy, component energy loss, and emissions control in Class 8 trucks over both city and highway driving conditions. A comprehensive set of component models describing engine fuel consumption, emissions control, battery energy, and accessory power demand interactions was developed and integrated with the simulated hybrid trucks to identify heavy-duty (HD) hybrid technology barriers. The results show that series hybrid is absolutely negative for fuel-economy improvement of long-haul trucks due to an efficiency penalty associated with the dual-step conversions of energy (i.e. mechanical to electric to mechanical). The current parallel hybrid technology combined with 50% auxiliary load reduction could improve fuel economy by 5-7% in long-haul trucks, but a profound improvement of long-haul truck fuel economy requires innovative technologies for reducing aerodynamic drag and rolling resistance. The simulated emissions control indicates that hybrid trucks produce less carbon monoxide (CO) and hydrocarbons (HC) emissions than conventional trucks. The results further indicate that the catalyzed diesel particulate filter (CDPF) played an important role in CO…
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