Characterization of Emissions from Hybrid-Electric and Conventional Transit Buses

McKain, David L.; Clark, Nigel N.; Balon, Thomas; Moynihan, Paul; Lynch, Sheila; Webb, Thomas C.

doi:10.4271/2000-01-2011

Cited by 45 publications

(30 citation statements)

References 4 publications

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“…They were also found to produce low CO and HC emissions. Previous results (McKain et al 2000;CASE 2001;Bass and Alfermann 2003;Wayne et al 2004;Chandler and Walkowicz, 2006; showed that the average NOx emissions from hybrid-electric diesel buses were about 25-30% lower than those from conventional diesel buses while average FE of the hybrid-electric diesel buses was about 20-25% higher than that from diesel buses. However, the percentage of FE benefit from the hybrid buses was route (or cycle) dependant.…”

Section: Introductionmentioning

confidence: 99%

“…Dynamometer assisted braking is not representative of real-world use. It affected emissions and fuel consumption from hybrid-electric vehicles since a significant percentage of fuel economy advantage from the hybridelectric vehicles resulted from the regenerative process during braking McKain et al 2000;Bass and Alfermann 2003). The first and the third bus on some drive cycles were also tested with dynamometer assisted braking, and these runs were not included for analysis.…”

Section: Actual and Target Speedmentioning

confidence: 99%

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Regulated and Non-Regulated Emissions and Fuel Economy from Conventional Diesel, Hybrid-Electric Diesel, and Natural Gas Transit Buses

Wayne¹,

Kahn²,

Gautam³

et al. 2012

J Transp Res Forum

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Section: Introductionmentioning

confidence: 99%

Section: Actual and Target Speedmentioning

confidence: 99%

Regulated and Non-Regulated Emissions and Fuel Economy from Conventional Diesel, Hybrid-Electric Diesel, and Natural Gas Transit Buses

Wayne¹,

Kahn²,

Gautam³

et al. 2012

J Transp Res Forum

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“…Research has shown that HEBs perform well against conventional diesel buses in urban areas with generally low speed transient traffic environments (McKain & Clark, 2000;Wayne et al, 2008). Initial research of HEBs and conventional buses (CB) controlling for bus routes showed no difference in fuel economy (Wayne et al, 2004).…”

Section: Hybrid-electric Buses (Heb)mentioning

confidence: 99%

Bus Replacement Modeling and the Impacts of Budget Constraints, Fleet Cost Variability, and Market Changes on Fleet Costs and Optimal Bus Replacement Age, A Case Study

Boudart

2000

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Overwhelming evidence throughout the literature has shown that bus overhead and maintenance (O&M) costs increase as buses age. This has implications toward a fleet manager's decision of when one should buy, use, or sell buses to minimize total fleet costs. Unfortunately, there are uncertain market conditions associated with bus fleets that cloud the manager's ability These data have been analyzed to create statistical relationships based on rising O&M costs per mile with age, which are then integrated with the IP model to determine the impact of changing diesel prices, potential carbon dioxide (CO2) emissions costs, uncertain maintenance costs, and bus purchase cost subsidies. The goal is to aid fleet managers to determine the costs of early or delayed suboptimal bus replacement timing and the impacts of market variability on fleet costs and optimal replacement timing.ii The optimal replacement age for NF and NF hybrid buses based on King County data and current fuel prices of $3.99/gal are 16.7 and 18.3 years, respectively. It has been consistently observed that greater expense is incurred when buses are replaced earlier rather than later from optimal. To minimize total CO2 emissions (including operation and construction emissions), buses should be replaced slightly before the optimal replacement time without considering CO2 emissions. High diesel prices and CO2 emissions had little or no effect, on when buses should be replaced. However, higher maintenance costs reduced the optimal replacement time by almost two years.Although NF hybrid buses have been found to have no economic advantage over conventional buses, this finding may be a consequence of the different costs associated to the different routes operated by hybrid and conventional buses. Due to the lack of detailed King County's route level historical data, a study of the economic competiveness of NF hybrids against conventional buses is outside the scope of this thesis.If buses are used less with age, the optimal replacement age is reduced.The optimal replacement age also dropped significantly when the Federal Transit Agency's procurement assistance is applied into the model. The iii procurement assistance can be up to 80% of the capital costs and can be considered a purchase subsidy from the transit agency viewpoint. If purchase subsidies decrease bus purchase prices by 1%, the optimal replacement age drops approximately 1.5%. When the bus purchase price is reduced by 80%, the optimal bus replacement age is less than 12 years, the FTA's minimum replacement age.

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“…Therefore, we decided to adopt the procedures proposed in [16]. The chassis-based driving schedule for heavy-duty vehicles (UDDSHDV), as opposed to an engineonly dynamometer cycle is adopted.…”

Section: Preliminary Rule Based Control Strategymentioning

confidence: 99%

“…For UDDSHDV, emissions are recorded and reported in the unit of gram per mile (g/mi). In addition, the battery SOC correction procedure proposed in [16] is used to correct fuel economy and emissions. The hybrid electric truck with the preliminary rule-based controller was tested through simulation over the UDDSHDV cycle.…”

Section: Preliminary Rule Based Control Strategymentioning

confidence: 99%

Energy management strategy for a parallel hybrid electric truck

Lin

Kang

Grizzle

et al. 2001

Proceedings of the 2001 American Control Conference. (Cat. No.01CH37148)

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Hybrid vehicle techniques are widely studied recently because of their potential to significantly improve the fuel economy and drivability of future ground vehicles. Due to the dual-power-source nature of these vehicles, control strategies based on engineering intuition frequently fail to fully explore the potential of these advanced vehicles. In this paper, we will present a procedure for the design of a near-optimum power management strategy. The design procedure starts by defining a cost function, such as minimizing fuel consumption and selected emission species. The Dynamic Programming (DP) techniques are then utilized to find the optimal control actions. Through analysis of the behavior of the DP control actions, sub-optimal rules are extracted, which, unlike DP control signals, are implementable. The performance of the power management control strategy is verified by using the hybrid vehicle model HE-VESIM developed at the Automotive Research Center of the University of Michigan. A trade-off study between fuel economy and emissions was performed. It was found that significant emission reduction can be achieved at the expense of small increase in fuel consumption.

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Characterization of Emissions from Hybrid-Electric and Conventional Transit Buses

Cited by 45 publications

References 4 publications

Regulated and Non-Regulated Emissions and Fuel Economy from Conventional Diesel, Hybrid-Electric Diesel, and Natural Gas Transit Buses

Regulated and Non-Regulated Emissions and Fuel Economy from Conventional Diesel, Hybrid-Electric Diesel, and Natural Gas Transit Buses

Bus Replacement Modeling and the Impacts of Budget Constraints, Fleet Cost Variability, and Market Changes on Fleet Costs and Optimal Bus Replacement Age, A Case Study

Energy management strategy for a parallel hybrid electric truck

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