The Configuration Design and Control for an Ejector-Based Hydrogen Recirculation System on High-Power Fuel Cell Engines

A promising direction for high-power fuel cell engines is the ejector-based hydrogen recirculation system. As a first step, a hybrid hydrogen recirculation system configuration, consisting of a passive single ejector and a bypass injector, has been proposed. For the system matching design, both a three-dimensional numerical model of the ejector using the computational fluid dynamics method (CFD) and a one-dimensional system level model were constructed. Sensitivity analysis was conducted on the ejector performance of secondary flow parameters. Additionally, the configuration validation test bench and engine prototype both were built, and steady-state and dynamic response tests were carried out. Based on multi-state feed-forward plus feedback control, a segmentation hydrogen hybrid control algorithm was developed. Results show that the proposed ejector-based hydrogen recirculation system configuration is able to achieve the hydrogen excess ratio demand within the range of high-power fuel cell engines with a power range of 10-100%. Moreover, the steady state of the inlet pressure control error of the commercial engine is maintained at +/- 2 kPa, with the error of the Purge stage kept within +/- 5 kPa.