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

Abstract

The fuel economy and emissions of conventional and hybrid buses equipped with emissions after treatment 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. Finally, 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.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Transportation Research Center (NTRC)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Transportation Research Center (NTRC)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
OSTI Identifier:
1319203
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Transportation Research Record
Additional Journal Information:
Journal Volume: 2570; Journal ID: ISSN 0361-1981
Publisher:
National Academy of Sciences, Engineering and Medicine
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 33 ADVANCED PROPULSION SYSTEMS

Citation Formats

Gao, Zhiming, Daw, C. Stuart, Smith, David E., LaClair, Tim J., Parks, James E., and Jones, Perry T. Comparison of Parallel and Series Hybrid Power Trains for Transit Bus Applications. United States: N. p., 2016. Web. doi:10.3141/2570-11.
Gao, Zhiming, Daw, C. Stuart, Smith, David E., LaClair, Tim J., Parks, James E., & Jones, Perry T. Comparison of Parallel and Series Hybrid Power Trains for Transit Bus Applications. United States. doi:10.3141/2570-11.
Gao, Zhiming, Daw, C. Stuart, Smith, David E., LaClair, Tim J., Parks, James E., and Jones, Perry T. 2016. "Comparison of Parallel and Series Hybrid Power Trains for Transit Bus Applications". United States. doi:10.3141/2570-11. https://www.osti.gov/servlets/purl/1319203.
@article{osti_1319203,
title = {Comparison of Parallel and Series Hybrid Power Trains for Transit Bus Applications},
author = {Gao, Zhiming and Daw, C. Stuart and Smith, David E. and LaClair, Tim J. and Parks, James E. and Jones, Perry T.},
abstractNote = {The fuel economy and emissions of conventional and hybrid buses equipped with emissions after treatment 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. Finally, 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.},
doi = {10.3141/2570-11},
journal = {Transportation Research Record},
number = ,
volume = 2570,
place = {United States},
year = 2016,
month = 8
}

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Free Publicly Available Full Text
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  • The fuel economy and emissions of both 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 indicate that series hybrid buses have the greatest overall advantage in fuel economy. The series and parallel hybrid buses were predicted to produce similar CO and HC tailpipe emissions but were also predicted to have reduced NOx tailpipe emissions compared to the conventional bus in higher speed cycles. For the New York bus cycle (NYBC), which has the lowestmore » average speed among the cycles evaluated, the series bus tailpipe emissions were somewhat higher than they were for the conventional bus, while the parallel hybrid bus had significantly lower tailpipe emissions. All three bus powertrains were found to require periodic active DPF regeneration to maintain PM control. Plug-in operation of series hybrid buses appears to offer significant fuel economy benefits and is easily employed due to the relatively large battery capacity that is typical of the series hybrid configuration.« less
  • Load-commutated full-and half-bridged series resonant inverters are dual at lower operating frequencies where the di/dt inductance L{sub s} has negligible effect on their performance. At higher frequencies, however, the effect of inductor L{sub s} dominates the ratings of components, and their performance is significantly different. The difference in their performance is a function of the operating frequency and is more pronounced at higher frequencies. To study the behavior of inverters at higher frequencies, a detailed analysis is presented which includes the effect of the di/dt inductance. Finally, the performance of two inverters is compared in terms of inverter kVA rating,more » and the kVA rating of the compensating capacitor.« less
  • Various silicon hybrid systems are modeled and compared with a gallium arsenide hybrid system. The hybrid systems modeled produce electric power and also thermal power which can be used for heating or air conditioning. Various performance indices are defined and are used to compare the system performance. The performance indices are: capital cost per unit electric power out; capital cost per total power out; capital cost per unit electric power plus mechanical power; annual cost per unit electric energy; and annual cost per unit electric plus mechanical work. These performance indices indicate that concentrator hybrid systems can be cost effectivemore » when compared with present day energy costs. Realistic costs and efficiencies of GaAs and Si are respectively $35,000/m/sup 2/ for 15 percent efficient solar cells and $1000/m/sup 2/ for 10 percent efficient solar cells based on information available at the time of this study in late 1975. The performance indices show that the limiting values for annual costs are 10.3 cents/kWh and 6.8 cents/kWh for Si and GaAs, respectively. Results demonstrate that for a given flow rate there is an optimal operating condition for maximum photovoltaic output associated with concentrator systems. Also concentrator hybrid systems produce a distinct cost advantage over flat hybrid systems. 35 references.« less
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