Simulations of the Fuel Economy and Emissions of Hybrid Transit Buses over Planned Local Routes

Gao, Zhiming; LaClair, Tim J.; Daw, C. Stuart; Smith, D. D.; Franzese, Oscar

doi:10.4271/2014-01-1562

Cited by 13 publications

(20 citation statements)

References 18 publications

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“…[28], is adopted to determine the power requirement of the vehicle powertrain based on the transit bus's forward speed, acceleration, rotational inertia, aerodynamic loss, rolling resistance loss, and the road grade. For any instant of time, the bus tractive power is described as: (1) where is the tractive power of the bus; V is velocity; is air density; is the bus's aerodynamic drag coefficient; is the rolling resistance coefficient;…”

Section: Vehicle Energy Calculationmentioning

confidence: 99%

“…In this equation, is the fuel lower heating value (43,500 kJ/kg for diesel); is the engine peak power; and is the engine efficiency. Equation (3b) was derived based on a MD engine map [1].…”

Section: Vehicle Energy Calculationmentioning

confidence: 99%

“…Included among the seven million medium-duty (MD) vehicles currently registered in the U.S. are a significant number of city transit buses which receive significant federal, state and local subsidies [1][2]. Most city transit buses, which often are still powered by diesel engines, travel more than ten hours and one hundred miles daily.…”

Section: Introductionmentioning

confidence: 99%

“…Despite being equipped with state-of-the-art aftertreatment devices to meet stringent emissions regulations, Gao et.al. [1] and Noel et.al [3] reported that these diesel buses contribute significantly to air pollution and related air-borne health issues in urban areas. Meanwhile, their frequent stop-and-go operation and significant idling time lead to poor fuel economy and generate remarkable amounts of greenhouse gases (GHGs), which lead to long-term effects on global warming.…”

Section: Introductionmentioning

confidence: 99%

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

Gao

Lin

LaClair

et al. 2017

Energy

Self Cite

224

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This paper evaluates the energy consumption and battery performance of city transit electric buses operating on real day-today routes and standardized bus drive cycles, based on a developed framework tool that links bus electrification feasibility with real-world vehicle performance, city transit bus service reliability, battery sizing and charging infrastructure. The impacts of battery capacity combined with regular and ultrafast charging over different routes have been analyzed in terms of the ability to maintain city transit bus service reliability like conventional buses. The results show that ultrafast charging via frequent short-time boost charging events, for example at a designated bus stop after completing each circuit of an assigned route, can play a significant role in reducing the battery size and can eliminate the need for longer duration charging events that would cause schedule delays. The analysis presented shows that significant benefits can be realized by employing multiple battery configurations and flexible battery swapping practices in electric buses. These flexible design and use options will allow electric buses to service routes of varying city driving patterns and can therefore enable meaningful reductions to the cost of the vehicle and battery while ensuring service that is as reliable as conventional buses.

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Section: Vehicle Energy Calculationmentioning

confidence: 99%

Section: Vehicle Energy Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Gao

Lin

LaClair

et al. 2017

Energy

Self Cite

224

View full text Add to dashboard Cite

show abstract

“…We used a similar approach to determine activity distribution for transit buses by examining 12 driving schedules, which included Orange County Transit Agency (OCTA), Washington Metropolitan Area Transit Agency (WMATA), and others described in the SID. All cycles were used as prescribed except for the Knoxville Area Transit (KAT) driving schedule, where we removed 3000 sec of idle that occurred at the end of the cycle (Gao et al, 2014). The average velocities without idle in city, arterial, and highway activities of the 12 driving schedules were 6.6, 18.9, and 49.8 miles per hour (mph), respectively.…”

Section: Transit Busesmentioning

confidence: 99%

Future methane emissions from the heavy-duty natural gas transportation sector for stasis, high, medium, and low scenarios in 2035

Clark

Johnson

McKain

et al. 2017

Journal of the Air & Waste Management Association

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Newly collected pump-to-wheels methane emissions data for current natural gas technologies were combined with future market growth scenarios, estimated technology advancements, and best practices to examine the climate benefit of future fuel switching. The analysis indicates the necessary targets of efficiency, methane emissions, market penetration, and best practices necessary to enable a pathway for natural gas to reduce the carbon intensity of the heavy-duty transportation sector.

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The evaluation of developing vehicle technologies on the fuel economy of long-haul trucks

Gao

Smith

Daw

et al. 2015

Energy Conversion and Management

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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 21 st 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 nonoptimal interactions. Major factors to be considered in system integration are discussed.

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Simulations of the Fuel Economy and Emissions of Hybrid Transit Buses over Planned Local Routes

Cited by 13 publications

References 18 publications

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

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

Future methane emissions from the heavy-duty natural gas transportation sector for stasis, high, medium, and low scenarios in 2035

The evaluation of developing vehicle technologies on the fuel economy of long-haul trucks

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