Characterization of Energy Distribution and Efficiency in a Modern Heavy-Duty Diesel Engine

This study presents an assessment focused on benchmarking the energy distribution and engine efficiency of a pre-2014, United States Environmental Protection Agency (USEPA) 2010 emissions-compliant, heavy-duty (HD) diesel, long-haul truck engine as a reference of baseline technology. Further, the study used the baseline energy distribution as the baseline to factor in the efficiency gains of various future engine technologies to evaluate the impact of future greenhouse gas (GHG) standards on HD vehicle fuel consumption. Furthermore, the study predicted the maximum achievable fuel consumption benefit from a future engine technology that will employ breakthrough technologies that are not in the near-term production pathway of engine manufacturers. The baseline energy distribution was experimentally assessed by conducting a detailed engine dynamometer testing of an HD diesel engine over a wide range of engine operations. The fuel consumption prediction results for the model year (MY) 2017 and MY 2020-future (2020+) engine platforms showed reductions of 7.9% and 18.3%, respectively, relative to baseline engine fuel consumption. The study predicts future technologies will result in lower energy loss to exhaust, pumping work, and the coolant circuit. The possibility of a waste heat recovery (WHR) system shows promise of delivering a maximum of 3% improvement to the brake thermal efficiency (BTE) for a MY 2020+ engine technology. Overall, the study sought to provide a detailed breakdown of engine energy flows and loss mechanisms involved that can help in model development to forecast the impact of modern technologies on overall engine efficiency.