Comparative Analysis of Internal Combustion Engine and Fuel Cell Range Extender

Fuel cells offer a high-efficiency and low-emission alternative to internal combustion engines (ICE) in vehicle applications. The fuel cell is silent, vibration free and zero emissions at point of use which allows the vehicle engineer considerably greater operational flexibility than with an ICE. The engineer is no longer constrained by the need to maintain discrete power levels to minimise noise intrusion, or switch the ‘engine’ off at low vehicle speeds to reduce noise and vibration. This paper presents simulation work comparing the performance of a typical B-segment electric vehicle with either a fuel cell or an ICE range extender over a number of real-world drive cycles. Intelligent Energy’s ‘Gen4’ air cooled fuel cell system is detailed as the fuel cell range extender, a typical 660cc naturally aspirated gasoline engine is considered for comparison. The results show that a fuel cell can be operated for a greater portion of an urban drive cycle than an ICE, which in turn means a lower power range extender can meet urban and extra-urban drive cycle average power requirements. As it is nearly silent, the fuel cell is also free to follow the driving power demand as far as possible, reducing charging and discharging losses in the battery and DC/DC converter. The analysis suggests up to 40% less fuel energy is required from the fuel cell compared to an ICE to cover the same distance, and that a fuel cell can match the performance of a combustion engine range extender with up to twice the rated power output.