Hyun Joon Lee

The Study of the Design and Control for the Hydrogen Recirculation Blower Noise and Vibration Reduction

At the fuel processing system (FPS) of fuel cell vehicle, hydrogen recirculation blower (HRB) is used for the recirculation of remained hydrogen after reaction. In this paper, noise and vibration improvement of HRB is studied by changing design and control. It is checked the campbell diagram and critical speed for stability of rotor, and housing stiffness is improved using simulation of frequency response function (FRF). A method is suggested that can decrease the unbalance amount of the rotor and impeller which main source of noise and vibration. In order to reduce the noise during deceleration of blower, electrical braking is applied and tested the risk impact of durability. Founded the optimum switching frequency of the motor control, and reduced the idle rpm by increasing of aerodynamic performance. The superiority of paper is proved by measurement of the improved products noise and vibration.

Development of the Integrated Exhaust System and Techniques of Nitrogen and Condensate for Fuel Cell Electric Vehicle

Abstract >> Proper discharge of nitrogen gas and water condensate is required in a conventional fuel cell systemfor performance, stability and durability of fuel cell stacks. Present study covers the development of integratedunit and its functioning logic for simultaneous nitrogen gas purge and water condensate drainage in a fuel cellvehicle system. Configuration of condensate drainage pipe, purge valve and level sensor is considered and optimizedin physical integration. As a key factor, discharge time is considered and optimized based on the test result ofconstant-current operation with various operating temperature in logic development. Consequently, derived optimalvalues are applied and verified in actual vehicle drive mode test.Increase of system design flexibility, weight reduction and cost reduction are anticipated with this study. Additional study for physical and logical improvement is currently being implemented. Key words : Nitrogen purge(질소 배출), Condensate drainage(응축수 배출), Electrochemical reaction(전기화학반응), Fuel cell(연료전지), Constant-current driving test(정전류 운전 시험)