A Comparison of Emissions and Fuel Economy from Hybrid-Electric and Conventional-Drive Transit Buses

Wayne, W. Scott; Clark, Nigel N.; Nine, Ralph D.; Elefante, Dennis

doi:10.1021/ef030096t

Cited by 45 publications

(26 citation statements)

References 5 publications

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“…However, most of the HC mass consisted of methane. Emissions from NGB across North America and Europe have been well-documented in numerous published studies (Wang et al 1993;Clark et al 1997;McCormick et al 1999;Weaver et al 2000;Wayne et al 2004;.…”

Section: Introductionmentioning

confidence: 91%

“…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: 94%

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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: 91%

Section: Introductionmentioning

confidence: 94%

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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“…The hybrid bus and one of the CNG buses had the lowest CO emissions, and the hybrid bus and buses equipped with continuously regenerated trap (CRT) exhaust aftertreatment had hydrocarbon emissions that were below the detectable limit of the instrument used. Wayne et al (2004) evaluated three transit vehicles, a seriesdrive hybrid-electric, a conventional drive diesel-powered, and a conventional-drive liquefied natural gas (LNG)-powered bus. They evaluated the buses on a chassis dynamometer over several cycles.…”

Section: Introductionmentioning

confidence: 99%

Comparison of on-road emissions for hybrid and regular transit buses

Hallmark

Wang

Sperry

2013

Journal of the Air & Waste Management Association

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Hybrid technology offers an attractive option for transit buses, since it has the potential to significantly reduce operating costs for transit agencies. The main impetus behind use of hybrid transit vehicles is fuel savings and reduced emissions. Laboratory tests have indicated that hybrid transit buses can have significantly lower emissions compared with conventional transit buses. However, the number of studies is limited and laboratory tests may not represent actual driving conditions, since in-use vehicle operation differs from laboratory test cycles. This paper describes an on-road evaluation of in-use emission differences between hybrid-electric and conventional transit buses for the Ames, Iowa transit authority, CyRide. Emissions were collected on-road using a portable emissions monitoring system (PEMS) for three hybrid and two control buses. Emissions were collected for at least one operating bus day. Each bus was evaluated over the same route pattern, which utilizes the same driver. The number of passengers embarking or disembarking at each stop was collected by an on-board data collector so that passenger load could be included. Vehicle emissions are correlated to engine load demand, which is a function of factors such as vehicle load, speed, and acceleration. PEMS data are provided second by second and vehicle-specific power (VSP) was calculated for each row of data. Instantaneous data were stratified into the defined VSP bins and then average modal emission rates and standard errors were calculated for each bus for each pollutant. Pollutants were then compared by bus type. Carbon dioxide, carbon monoxide, and hydrocarbon emissions were higher for the regular buses across most VSP bins than for the hybrid buses. Nitrogen oxide emissions were unexpectedly higher for the hybrid buses than for the control buses.Implications: The main reason agencies consider hybrid transit vehicles is fuel savings and reduced emissions. Hybrid electric buses offer an attractive option and have the potential to significantly reduce operating costs and emissions for transit agencies. However, purchase of hybrid buses cost 50-70% more than regular buses. As a result, agencies require more quantitative information about the on-road costs and benefits of hybrid buses. This study assessed on-road emissions for in-use transit buses. The resulting information can be used by transit agencies in assessing the likely emission reduction benefits for hybrid buses.

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“…There were many possibilities made local concentration of PM 2.5 unstable, including the type of bus engine, emission frequency, and convection condition. The diesel engines have been shown to emit higher level of particulate emission (Wayne et al, 2004;Bitterman and Hess, 2008).…”

Section: Atmospheric Pm 25 Mass Concentration Level Around Bus Stationmentioning

confidence: 99%

Reduction of Atmospheric PM2.5 Level by Restricting the Idling Operation of Buses in a Busy Station

Lee

Lin

Aniza

et al. 2017

Aerosol Air Qual. Res.

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Fine particulate matter (PM 2.5 ) has been found to be harmful when inhaled by people, which has caused enormous health problems. It is found at high levels at public bus stations, where many passengers and workers may be exposed to PM 2.5 emissions from idling diesel engines. This study evaluated the restriction on idling vehicles as a strategy to control PM 2.5 levels at bus stations by measuring the PM 2.5 and the chemical properties at both upwind and exposure sites for comparable data. The sampling took place on weekends and weekdays and before and after the idling restriction was applied. Originally, the exposure site showed a PM 2.5 level that was 7% higher, non-neutralized nitrate content, anthropogenic metal elements, and higher mobile source contributions, as evaluated by a chemical mass balance model (CMB8.2). After the prohibition on idling heavy-duty diesel vehicles, the PM 2.5 mass concentrations at the exposure site were reduced to levels comparable to those at the upwind site. Additionally, the nitrate content was reduced in the background. Moreover, the contributions of several anthropogenic metals (Zn, Pb, Mn, Cu, Cr, V, Ni, and Ti) in PM 2.5 were reduced while those of crustal elements (Na, Mg, Al, K, and Ca) significantly increased after the restriction. Finally, the mobile contribution decreased to only 33.7-34.5%. Consequently, these findings verify that the prohibition policy on idling vehicles works well as a control strategy to manage the PM 2.5 emissions at local hotspots such as bus stations.

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A Comparison of Emissions and Fuel Economy from Hybrid-Electric and Conventional-Drive Transit Buses

Cited by 45 publications

References 5 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

Comparison of on-road emissions for hybrid and regular transit buses

Reduction of Atmospheric PM2.5 Level by Restricting the Idling Operation of Buses in a Busy Station

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