The Effects of Start-Up and Shutdown of a Fuel Cell Transit Bus on the Drive Cycle

Fuel cell engines are expected to deliver greater efficiency and lower emissions than conventional powertrains during operation. However, the projected efficiency and emission benefits of using fuel cell derived power can be significantly reduced if the fuel consumed and emissions produced during start-up and shutdown procedures are included in the analysis of the overall drive cycle. For this reason, an investigation of the drive cycle including the fuel consumed, power required, and emissions produced during the start-up and shutdown of an operational, heavy duty methanol-fueled fuel cell bus has been performed. The fuel consumed and emissions generated during start-up and shutdown were measured and combined with steady operation values to allow mission equivalent fuel mileage and emission outputs to be computed. The results show that the start-up and shutdown contributions can be significant and should be included in fuel efficiency and emission projections.