Performances Analysis of PEM Fuel Cell Based Automotive Systems Under Transient Conditions

The use of Polymeric Electrolyte Membrane Fuel Cells (PEMFC) based power trains as a substitute of Internal Combustion Engines (ICE) in transportation has been demonstrated but still requires both technical development of components and their integration in the system. One of the major technical challenges for automotive application is the system response during rapid variations of operative conditions, which is one of the most significant elements concurring in determining the vehicle drivability (i.e. the power train capability to allow rapid transient phenomena). The power train response under transient conditions depends on the combined action of all the system components performances. This behaviour is still more complicated when hydrogen has to be produced on board and the reformer response has to be taken into account.

In this paper the performances of PEMFC based energy production systems for automotive applications is analysed by means of a simulation model able to describe the performance of all the system components from the on board energy storage to the road load. Different fuel storage/production solutions are analysed and their performances are compared (methanol steam reformer, methane auto thermal reformer and ammonia reformer).

To increase results significance, comparison are made with respect to the European Urban Cycle (ECE+EUDC) and to this aim a simple model of vehicle dynamics has been also developed.

Model predictions have proved to be able to simulate system behaviour and could be used to design system characteristics as well to define its control system.