Exploring Fuel-Saving Potential of Long-Haul Truck Hybridization

Abstract

Comparisons are reported on the simulated fuel economy for parallel, series, and dual-mode hybrid electric long-haul trucks, in addition to a conventional powertrain configuration, powered by a commercial 2010-compliant 15-L diesel engine over a freeway-dominated heavy-duty truck driving cycle. The driving cycle was obtained by measurement during normal driving conditions. The results indicated that both parallel and dual-mode hybrid powertrains were capable of improving fuel economy by 7% to 8%. However, there was no significant fuel economy benefit for the series hybrid truck because of internal inefficiencies in energy exchange. When reduced aerodynamic drag and tire rolling resistance were combined with hybridization, there was a synergistic fuel economy benefit for appropriate hybrids that increased the fuel economy benefit to more than 15%. Long-haul hybrid trucks with reduced aerodynamic drag and rolling resistance offered lower peak engine loads, better kinetic energy recovery, and reduced average engine power demand. Thus, it is expected that hybridization with load reduction technologies offers important potential fuel energy savings for future long-haul trucks.

Battery capacity and recharging needs for electric buses in city transit service

“…Similarly, a constant value for the accessory load is used in the electric bus simulation. Since there are less accessory components in an EV, the accessory load for the electric bus is assumed to be 50% less than that used in a conventional vehicle based on data published in the literature [32][33][34]. However, compared to a conventional vehicle, the battery and related electronic components used in an electric vehicle typically lead to a significant weight penalty due to the low energy density of the battery.…”

Energy Consumption and Cost Savings of Truck Electrification for Heavy-Duty Vehicle Applications

“…Similarly, the e-truck simulation used a constant value for the accessory load. Because there are fewer accessory components in an e-truck, the accessory load for the e-truck was assumed to be 50% less than that used in a conventional vehicle based on widely published literature (17)(18)(19).…”

Comparison of Parallel and Series Hybrid Power Trains for Transit Bus Applications

“…The model is capable of effectively simulating both the steady-state and transient battery responses that are observed in Li-ion batteries. The model has been validated with experimental measurements (25). Simulated voltage profiles generated with the model for a Li-ion battery subjected to periodic pulse discharges and charges matched experimental measurements to within 1% except when the accumulated charge level was below 5% (which does not commonly occur in real-world operation).…”

“…The catalytic DPF model was validated with experimental dynamometer measurements using a Corning EX-80 cordierite DPF on a heavy-duty engine (20,24). The computational models developed at ORNL are not available in the public version of Autonomie, but additional details and calibration information for each of the ORNL component models have been published previously (4,14,20,22,25,26). To account for required emissions controls, both the conventional and hybrid buses were assumed to be equipped with a 2.3 L DOC, 9.7 L catalyzed DPF, and 7.7 L SCR catalyst, positioned as shown in Figure 1.…”

“…To utilize appropriate engine-battery control strategies, an equivalentcircuit battery dynamic model was developed on the basis of data available in the open literature (25), to account for additional bat-tery physics using electrical circuit analog components. These components include voltage sources, variable resistors, and capacitors.…”