Off-Design Operation of a Carbon Capture Enabler Oxyfuel Combustion Engine with O₂ Self-Production

This work examines the behaviour of a spark-ignition engine using oxy-fuel combustion, coupled with an oxygen production cycle based on a mixed ionic-electronic ceramic membrane. Through 1D-0D simulations, two compression ratios are studied: the original ratio of 9.6 and the optimised CR of 20, under various load levels and altitude conditions. The results show that operational limits exist at part-load conditions, where reducing the load without implementing additional control strategies may compromise system performance. It is observed that at low loads, the intake pressure can fall below atmospheric pressure, encouraging the presence of N2 in the combustion process. Additionally, the engine can operate efficiently up to an altitude of 4,000 m, although increasing boosting is required to maintain proper membrane conditions. These findings emphasise the importance of load control and the potential need for energy assistance under certain circumstances.