Analysis of the fuel economy improvement potential of ethanol hybrid buses
2011 (English)In: Proceedings of the 24th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2011, Nis University , 2011, 2220-2229 p.Conference paper (Refereed)
With the ambitions to further increase its share of renewable fuels and to reduce the amount of carbon dioxide emissions, local emissions and noise, Stockholm Public Transport (SL) hosted a one-year project to evaluate the performance of ethanol hybrid buses. An important part of the project was the duty cycle tests according to SORT - Standardised On-Road Tests cycles (developed by the International Association of Public Transport, UITP). The duty cycle tests generated experimental data, on which this paper’s discussion is based upon. The purpose of this article is to evaluate the potential of energy-efficiency improving measures on the powertrain. The ethanol hybrid bus is a series hybrid vehicle with regenerative braking. A start/stop software to avoid idling was optional. A bus with similar exterior properties, but with the ethanol internal combustion engine coupled to a conventional automatic gearbox instead of a hybrid powertrain was used as a reference throughout the project. Based on both experimental data and simulations, several measures to increase the overall energy-efficiency may be proposed. Assessed measures to increase the energy-efficiency include size optimization of powertrain components, such as energy storage and electric motor, and internal combustion engine (identified by using Sankey diagrams), adjustment of the super capacitors energy management system and utilisation of engine start/stop functionality. Analysis shows that the size of the energy storage is well attuned if applied as urban transport. It would be possible to downsize the ICE, from approximately 200 kW to approximately 150 kW, without losing substantial performance. Using the start/stop software reduces the fuel consumption with 15 % in the standardized city duty cycle but has the potential for even further fuel economy improvements in real traffic with more idling.
Place, publisher, year, edition, pages
Nis University , 2011. 2220-2229 p.
Ethanol hybrid bus, Series hybrid, Energy efficiency, Energy flow analysis, Sankey diagrams
IdentifiersURN: urn:nbn:se:kth:diva-107440ScopusID: 2-s2.0-84903642241ISBN: 978-866055016-5OAI: oai:DiVA.org:kth-107440DiVA: diva2:575926
The 24th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, July 4-7 2011, Novi Sad, Serbia
QC 201306042012-12-112012-12-112015-09-16Bibliographically approved