Start Date: 1.7.2009
End Date: 1.7.2013
Stijn v. Dooren
31.1.2011 Nachhaltigkeit.org repeats the ETH Life article.
21.1.2011 ETH Life reports on Philipp Elbert winning the Hans-Eggenberger Prize for his Masterthesis.
1.1.2011 Congratulations! Philipp Elbert's Masterthesis "Optimal Component Design for Serial Hybrid Electric Buses" was awarded the Hans Eggenberger Prize.
1.10.2007 Stadtbus.de Onlinemagazin
AHEAD Project Impressions
18m Hybrids by HESS on Schweiz Aktuell
Vossloh-Kiepe explain their Hybrid Technology used in HESS's lighTram Hybrid
A test drive in HESS's lighTram Hybrid
Elbert, P., Ebbesen, S. and Guzzella, L. (2011) Economic Viability of Battery Load-Leveling in Hybrid Electric Vehicles using Supercapacitors, Int. Scientific Conference on Hybrid Electric Vehicles, RHEVE 2011, Paris, France
Ebbesen, S. , Elbert, P. and Guzzella, L. (2011) Engine Downsizing and Electric Hybridization Under Consideration of Cost and Drivability, Int. Scientific Conference on Hybrid Electric Vehicles, RHEVE 2011, Paris, France Also accepted for publication in Oil & Gas Science and Technology - Revue d'IFP Energies Nouvelles
Elbert, P, Ebbesen, S, Guzzella, L. (2012) Implementation of Dynamic Programming for n-Dimensional Optimal Control Problems with Final State Constraints, IEEE Transactions on Control Systems Technology
This project aims at optimizing the powertrain of a serial hybrid electric bus for public transportation. Mathematical models and advanced optimization techniques are used to find the optimal component sizes of the powertrain. Further, a predictive energy management strategy that takes into account the altitude profile of the line is implemented. This cuts fuel consumption and CO2 emissions by 25% compared to a conventional, combustion-engine based vehicle.
This project is a cooperation of HESS AG (Bellach, Solothurn) and ETH Zürich. It is sponsored by KTI. This project was awarded the Hans Eggenberger Preis 2010, and won the second prize in the European Satellite Navigation Competition.
Hardware of a serial hybrid powertrain: Two electric traction motors propel the bus (see upper part of figure). Electric energy is delivered by an engine-generator set in the back of the vehicle. During downhill driving and braking maneuvers, the traction motors regenerate kinetic and potential energy, which is then stored in the electric double-layer capacitors (EDLCs) on the roof of the bus. This "recuperated" energy can be used for propulsion later on.
Information about future elevation profile allows saving energy: If the route is unknown (consider the scenario "without preview" in lower part of figure), the system is not aware of the upcoming descent and the energy content of the EDLCs has to be maintained on a medium level to provide enough power. Later on, during the long descent, the EDLCs cannot absorb all recuperation energy, since they are already half full, and the excess energy has to be wasted. With a preview of the altitude profile (scenario "with preview"), the control system is able to react prior to the long descent: during uphill driving, the EDLCs are discharged almost completely, which provides enough free capacity to accept recuperation energy. Overall, the scenarios starts and ends with an equal EDLC energy level, but in the case "with preview" less fuel was used.
Components have to fit vehicle and mission: The components of the powertrain have to be adjusted to the primary use of the bus. If for example the route is a flat and straight road without many stops the components will be very different from the case where the bus is driven in a hilly city. This project develops methods and tools to find the optimal design for a vehicle's primary use.
Project goals: In public transportation, where buses run only on very few routes, the design of the vehicle can be specialized and optimized. This project seeks
i) to find the optimal component sizes for a given vehicle on a given route;
ii) to implement a predictive energy management strategy that takes into account the future elevation profile.
Practical outcomes: HESS benefits from
i) reduced time and cost for development and design;
ii) the possibility to demonstrate and compare the performance of powertrain designs.
The costumer of a HESS bus benefits from
iii) reduced CO2 emissions;
iv) reduced fuel cost.
Scientific research topics: Hybrid electric vehicle design and optimization and predictive control of hybrid electric vehicles.
First tests and measurements with HESS's lighTram Hybrid on Buochs Airfield.
Diese Website wird in älteren Versionen von Netscape ohne graphische Elemente dargestellt. Die Funktionalität der Website ist aber trotzdem gewährleistet. Wenn Sie diese Website regelmässig benutzen, empfehlen wir Ihnen, auf Ihrem Computer einen aktuellen Browser zu installieren. Weitere Informationen finden Sie auf
The content in this site is accessible to any browser or Internet device, however, some graphics will display correctly only in the newer versions of Netscape. To get the most out of our site we suggest you upgrade to a newer browser.