A Development of the Purge Controller Design Based on H2 Concentration Estimator in Fuel Cell Electric Vehicle

The optimal control of anode H2 concentration in fuel cell is the key performance parameter for efficiency and durability of the fuel cell electric vehicle. Implementation of H2 concentration sensor in fuel processing system is the best option to achieve the optimal control operation, but the vulnerability of the chip in H2 concentration sensor to the moisture has not been overcome and no H2 concentration sensor for vehicle application is present in the world so far. Due to the immaturity of the H2 concentration sensor, a number of researches have been being made to keep the H2 concentration in the anode at certain level without H2 concentration sensors. However the effectiveness of those technologies has not been good to meet the design specification in all the operating range of the various driving cycles and environmental condition. Therefore, the need of the novel anode H2 concentration estimator has been demanded and the development has been carried out based on the knowledge of physical laws. The simple cubic box model with same volume of fuel processing system for embedded software in view of the minimization of calculation load and the easiness of debugging has been developed. Modeling simplification of plumbing and duct in H2 supply system causes estimation error depending on the driving cycle and environmental condition, but proper design of calibration parameters can make the error within reasonable range. In this paper, mathematical model of H2 concentration estimator is proposed and the effectiveness of purge controller based on estimator is demonstrated.