The objective of this assessment was to leverage current medium- and heavy-duty vehicle (MHDV) data and information to evaluate the state of commercial vehicle electrification technologies, including the following: 1. Assessment and inventory of current MHDV electrification architectures; 2. Identification and assessment of MHDV component technologies; 3. Assessment of potential performance and cost drivers; and, 4. Identification of R&D gaps where appropriate R&D and technology would accelerate commercial vehicle electrification. These gaps include shortfalls in technology, gaps in data, and inadequate knowledge and understanding. To inform this study, the National Renewable Energy Laboratory–Oak Ridge National Laboratory team examined the open literature; conducted workshops; assessed and analyzed data on more than 175 electrified MHDVs, including vehicle and powertrain specifications; and conducted one-on-one meetings with industry representatives. This systems-level information was concatenated and parsed with respect to key characteristics such as battery energy, power, and range compared across vehicle classes. Operational data of many conventional vehicles were also examined to help determine the requirements on electrified vehicle attributes such as range. Previous studies on the total cost of ownership of electrified MHDVs were reviewed to determine where improvements in technologies (efficiency, cost, maintenance) were needed to accelerate adoption. The team also assessed the state of the art in electric drivetrains for component specifications and challenges for the commercial vehicle sector, including electric machines, power electronics, and off-board high-power charging systems (extreme fast charging and beyond). The goal of this analysis was to identify the barriers to widespread adoption of commercial vehicle electrification technologies and prioritize the research and development gaps that need to be overcome to accelerate significant market penetration of these technologies.

During fiscal year 2019 (FY 2019), the U.S. Department of Energy (DOE) Vehicle Technologies Office (VTO) funded early stage research & development (R&D) projects that address Batteries and Electrification of the U.S. transportation sector. The VTO Electrification Sub-Program is composed of Electric Drive Technologies, and Grid Integration activities. The Electric Drive Technologies group conducts R&D projects that advance electric motors and power electronics technologies. The Grid and Charging Infrastructure group conducts R&D projects that advance grid modernization and electric vehicle charging technologies. This document presents a brief overview of the Electrification Sub-Program and progress reports for its R&D projects. Each of the progress reports provide a project overview and highlights of the technical results that were accomplished in FY 2019.

Inductive power transfer has been proposed as a solution to power future automated and electrified highways. In this study, an interoperable wireless charging system is sized so that a light and a heavy-duty vehicle can travel at or near charge-sustaining mode at high speeds using an optimization approach. The conflicting objectives of minimizing the power ratings and the number of inverters, coupler materials, and overall system coverages result in a Pareto Front that is presented in this paper. It is found that a system using short transmitting couplers can ensure high efficiency power transfers to light-duty vehicles (LDVs) and still maintain charge-sustaining operation of heavy-duty vehicles (HDVs). The findings are contextualized by a brief discussion of other aspects relating to the implementation of this technology on roadways such as the impact of the cost of time and travel speeds.

Electric drives, whether in battery electric vehicles (BEVs) or various other applications, are an important part of modern transportation. Traditionally, physics-based models based on steady-state mapping of electric drives have been used to evaluate their behavior under transient conditions. Hardware-in-the-Loop (HIL) testing seeks to provide a more accurate representation of a component's behavior under transient load conditions that are more representative of real world conditions it will operate under, without requiring a full vehicle installation. Oak Ridge National Laboratory (ORNL) developed such a HIL test platform capable of subjecting electric drives to both conventional steady-state test procedures as well as transient experiments such as vehicle drive cycles. This facility was used to compare the behavior of an electric drive installed in a BEV with the two methods: offline simulation built from the experimental steady state efficiency map, and HIL experimentation of the same electric drive simulating the same BEV. The aim of this study is to evaluate the accuracy of steady state map based simulation against experimental HIL results in the case of an electric drive. This paper first outlines HIL test procedures as well as the key aspects of utilizing steady-state maps to develop a model of the drive. Then both quantitative and qualitative differences in the experimental results obtained from the two processes are presented. Differences in specific transient behaviors between the two methods are discussed. Although both methods agree well in most transient situations, direct comparison of the offline simulation against the HIL results demonstrates that transient behaviors are not captured entirely by simulation alone.

The fuel economy and emissions of conventional and hybrid buses equipped with emissions aftertreatment were evaluated via computational simulation for six representative city bus drive cycles. Both series and parallel configurations for the hybrid case were studied. The simulation results indicated that series hybrid buses have the greatest overall advantage in fuel economy. The series and parallel hybrid buses were predicted to produce similar carbon monoxide and hydrocarbon tailpipe emissions but were also predicted to have reduced tailpipe emissions of nitrogen oxides compared with the conventional bus in higher speed cycles. For the New York bus cycle, which has the lowest average speed among the cycles evaluated, the series bus tailpipe emissions were somewhat higher than they were for the conventional bus; the parallel hybrid bus had significantly lower tailpipe emissions. All three bus power trains were found to require periodic active diesel particulate filter regeneration to maintain control of particulate matter. Plug-in operation of series hybrid buses appears to offer significant fuel economy benefits and is easily employed because of the relatively large battery capacity that is typical of the series hybrid configuration.

Results from computational simulations of fuel economy and engine-out emissions are presented for light-duty conventional and hybrid vehicles powered by conventional and high-efficiency combustion engines, including use of port fuel-injected, lean gasoline direct injection, reactivity controlled compression ignition, and conventional diesel combustion. The results indicate that multimode operation with conventional diesel combustion plus reactivity controlled compression ignition, conventional diesel combustion only, and lean gasoline direct injection has the potential to significantly exceed port fuel-injected fuel economy. In all cases, hybridization is predicted to significantly improve fuel economy by permitting the maximum exploitation of high efficiency engine combustion states. Predicted engine-out emissions vary considerably with combustion mode, with reactivity controlled compression ignition generating the highest carbon monoxide and hydrocarbon emissions. On the other hand, reactivity controlled compression ignition is predicted to generate the lowest emissions of nitrogen oxides. Importantly, lean gasoline direct injection and reactivity controlled compression ignition combustion modes are expected to dramatically decrease exhaust temperatures, especially for reactivity controlled compression ignition, which can potentially limit aftertreatment performance. While all results presented are from simulations, the results provide prediction of important details and trends for advanced vehicles that are currently extremely difficult to experimentally study. (C) 2015 Elsevier Ltd. All rights reserved.

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.

We present fuel savings estimates resulting from the combined implementation of multiple advanced energy management technologies in both conventional and parallel hybrid Class 8 diesel trucks. The energy management technologies considered here have been specifically targeted by the 21st Century Truck Partnership (21 CTP) between the U.S. Department of Energy and U.S. industry and include advanced combustion engines, waste heat recovery, and reductions in auxiliary loads, rolling resistance, aerodynamic drag, and gross vehicle weight. We estimate that combined use of all these technologies in hybrid trucks has the potential to improve fuel economy by more than 60% compared to current conventional trucks, but this requires careful system integration to avoid non-optimal interactions. Major factors to be considered in system integration are discussed. (C) 2015 Elsevier Ltd. All rights reserved.

We present simulated fuel economy and emissions city transit buses powered by conventional diesel engines and diesel-hybrid electric powertrains of varying size. Six representative city drive cycles were included in the study. In addition, we included previously published aftertreatment device models for control of CO, HC, NOx, and particulate matter (PM) emissions. Our results reveal that bus hybridization can significantly enhance fuel economy by reducing engine idling time, reducing demands for accessory loads, exploiting regenerative braking, and shifting engine operation to speeds and loads with higher fuel efficiency. Increased hybridization also tends to monotonically reduce engine-out emissions, but trends in the tailpipe (post-aftertreatment) emissions involve more complex interactions that significantly depend on motor size and drive cycle details.

This is a vehicle system level project, encompassing analytical modeling and supervisory controls development as well as experimental verification/validation testing at the component, powertrain, and full vehicle system level. This project supports the goal of petroleum consumption reduction for medium and heavy trucks through the development of advanced hybrid technologies and control systems. VSST has invested previously in R&D to support hybrid energy storage systems (Li-ion plus ultra-caps) for light duty, passenger car applications. This research will be extended to the MD and HD sector where current battery technology is not mature enough to handle the substantial regenerative braking power levels these trucks are capable of producing. With this hybrid energy storage system, substantial gains in overall vehicle efficiency are possible. In addition, advanced combustion technologies, such as RCCI, will be implemented into an advanced hybrid powertrain for a Class 8 line haul application. This powertrain, leveraged from other VSST work (Meritor, a current ORNL/VSST partner), is ideal for taking advantage of the benefits of RCCI operation due to its series hybrid mode of operation. Emissions control is also a focus of this project, especially due to the fact that RCCI creates a low temperature exhaust stream that must addressed.

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 oxidation besides particulate matter (PM) emissions control. Limited ammonia (NH3) emissions could be slipped from the urea selective catalytic reduction (SCR) designed for reducing nitrogen oxides (NOx), but the average NH 3 level are below 20 ppm. Meanwhile the estimations show 1.5-1.9% of equivalent fuel-cost penalty due to urea consumption in the simulated cases.

September 2014 OFFICIAL USE ONLY May be exempt from public release under the Freedom of Information Act (5 U.S.C. 552), exemption number and category: 4, Commercial/Proprietary Information. Department of Energy Review required before public release. Name/Org: Leesa Laymance/ORNL Date: 1/23/2015 PROTECTED CRADA INFORMATION This report contains protected CRADA information which was produced on September 5, 2014, under CRADA No. NFE-11-03310 and is not to be further disclosed for a period of five years from the date it was produced except as expressly provided for in the CRADA. PROTECTED CRADA INFORMATION This report contains protected CRADA information which was produced on September 5, 2014, under CRADA No. NFE-11-03310 and is not to be further disclosed for a period of five years from the date it was produced except as expressly provided for in the CRADA.

Plug-in hybrid electric vehicles (PHEV) operate predominantly as electric vehicles (EV) with intermittent assist from the engine. As a consequence, the engine can be subjected to multiple cold start events. These cold start events have a significant impact on tailpipe emissions due to degraded catalyst performance and starting the engine under less than ideal conditions. On current conventional vehicles, the first cold start of the engine dictates whether or not the vehicle will pass federal emissions tests. PHEV operation compounds this problem due to infrequent, multiple engine cold starts.ORNL, in collaboration with the University of Tennessee, developed an Engine-In-the-Loop (EIL) test platform to investigate cold start emissions on a 2.0l Gasoline Turbocharged Direct Injection (GTDI) Ecotec engine coupled to a virtual series hybrid electric vehicle. The end-goal of this project is to demonstrate the benefits of coordinating engine and powertrain supervisory control strategies to minimize cold start emissions.First, this paper provides a summary of the results obtained by optimizing engine cold start strategies on their own within the context of a PHEV application where the engine can be motored up to speed and supplemented with the electric machine. These specific operating modes open up new engine calibration opportunities. This study investigated the effect of different cranking injection, post-start load, idle speed and spark timing strategies.The paper then reports on the second phase of the project which focuses on the coordination of engine control strategies and hybrid energy management strategies. Stand-alone optimization of each component's algorithms does not guarantee that the resulting hybrid powertrain will operate efficiently. Therefore cold start strategies have to be controlled and optimized as a system to minimize tailpipe emissions. Comparison results of different coordination algorithms are presented to demonstrate the benefit of system coordination and optimization.

We report results from urban drive cycle simulations of a light-duty conventional vehicle and a similar hybrid electric vehicle, both of which are equipped with diesel engines capable of operating in either conventional diesel combustion mode or in premixed charge compression ignition mode. Both simulated vehicles include lean exhaust after-treatment trains for controlling hydrocarbon, carbon monoxide, nitrogen oxide, and particulate matter emissions. Our results indicate that, in the simulated conventional vehicle, premixed charge compression ignition can significantly reduce fuel consumption and emissions by reducing the need for lean nitrogen oxide traps and diesel particulate filter regeneration. However, the opportunity for utilizing premixed charge compression ignition in the simulated hybrid electric vehicle is limited because the engine typically experiences higher loads and multiple stop–start transients that are outside the allowable premixed charge compression ignition operating range. This suggests that developing ways of extending the premixed charge compression ignition operating range combined with improved control strategies for engine and emissions control management will be especially important for realizing the potential benefits of premixed charge compression ignition in hybrid electric vehicles.