Conceptual evaluation of a fuel-cell-hybrid powered bus

This paper considers the conceptual design of a fuel-cell-hybrid engine to replace the conventional diesel internal combustion engine for use in London buses. Fuel cells are expensive power units costing in the region of £2.50/W compared to the conventional diesel-engine at 5p/W. A fuel-cell-hybrid solution is proposed to minimize initial costs whilst achieving good operational performance and specifically reducing greenhouse gas emissions for future `zero-emission zones´. Different London bus types and their routes have been reviewed with route 226 (from Ealing Broadway Station to Golders Green Station) and the Alexander Dennis Enviro 200 Dart bus being selected for detailed study. Considering factors such as number of stops, route length, public demand, bus dimensions and weight a series fuel-cell-hybrid power plant using 20 kW polymer electrolyte membrane (PEM) fuel cells with a nano-phosphate Lithium-ion battery providing power to four AC three-phase induction propulsion motors is proposed. The fuel-cell-hybrid engine has been designed with re-engineering of the bus in mind to layout level and performance analysis has been undertaken using computer based simulation.