Investigation of Combined Compression-Ignition Combustion and Solid Oxide Fuel Cell System for High Efficiency Power Generation from Liquid Based Hydrocarbon Fuels

As global climate change concerns lead the automotive industry to push towards manufacturing more sustainable automobiles, a number of technologies and powertrains have developed. Less common among these new powertrains are fuel cell systems due to their relatively high cost and requirement of an associated fuel reformation process. This reformer is needed if widely available hydrocarbon fuels are to be used. There are currently few initiatives combining fuel cell systems with internal combustion engines, but these initiatives are unable to mitigate the primary drawbacks of fuel cell systems. Current designs place the engine downstream of the fuel cells, resulting in the same need for prior fuel processing. In this work, a configuration is considered in which the engine is placed upstream of the fuel cell system, and its syngas-rich exhaust is fed directly into the fuel cell system for electricity production. Fuel-rich compression-ignition engine combustion can break down fuel into hydrogen and carbon monoxide (syngas) and other minute hydrocarbon byproducts. Based on chemical kinetic model simulations, the composition of the syngas resulting from the fuel-rich combustion can be used to design test syngas compositions for the fuel cell system. The performance of micro-tubular solid oxide fuel cells (μT-SOFC) using this model exhaust as the primary fuel supply was then investigated. The SOFC was able to generate ~730 mW/cm2 on the model exhaust which corresponds to about ~86 % of the maximum power output obtained by fueling it with pure hydrogen. This demonstrates the potential of the suggested integration of an SOFC system with an internal combustion engine. Additionally, practical fuel-rich combustion in a combustion chamber and in a diesel engine was carried out to test and validate the simulated exhaust syngas composition. This promising innovative compact energy system eliminates both the need for fuel processing catalysts and the heating requirement for complex fuel reformers. It can be a more cost-effective high-efficiency solution than existing combined fuel cell system solutions.