Proton Exchange Membrane (PEM) fuel cells are becoming an increasingly important alternative to combustion engines as the fossil fuel reserves are depleted. Several papers have presented steady state analyses of the system, but few are known to present dynamic analysis of the flow and control of the hydrogen delivery process. This thesis presents the dynamic analysis of hydrogen delivery to a PEM fuel cell system. The hydrogen is delivered to the anode with use of an ejector for passive recirculation. The system to be studied consists of the manifolds, ejector, and pressure control valve. Models describing the elements of the anode delivery systems are formulated. The governing nonlinear equations are solved analytically and numerically, and the regimes of stable hydrogen delivery process are established. The linearized models are used for performance analysis and optimization of the hydrogen delivery process. The nonlinear model is used to improve the simulation of the dynamics of the PEM fuel cell system and validate the parameters at optimal linearized stability. Experiments are conducted to find the parameters used in the model, as well as validate the results. Both the linear and nonlinear models are implemented in Simulink and tested against the laboratory data from the PEM fuel cell system. The analysis showed that the models have the same time constant and dynamic behavior as the PEM system. The optimal parameters for stability and a faster response with no oscillations in the output are obtained. The redesigned valve and resulting dynamics of the PEM fuel cell system provides improved system performance.

The Diploma Thesis presents a draft of designated automatic apparatus for cutting out and assembling pads for pressure control valve (DRV2). The theoretical chapter of the Thesis contains selected findings from theory and technology for material cutting. The next chapter contains design solutions for a designated apparatus for cutting and assembling pressure control valves. The pads are etched from 0,08 mm steel plates X2CrNi Mol7-12-2. The shape of the pads is etched on a 35mm-wide belt that is wound up onto a drum. The draft of this new technological facility has been elaborated in accordance with the most suitable technological variant. The cutting tool is made of steel 19 437 that is thermally processed at HRC 62-4. Estimated annual volume of production series is 2 mil. pcs. The cutting and assembly processes are executed with the aid of this designated automatic apparatus.