Patent ID: 8557455

Claim:
A method for controlling the feedback of hydrogen from a reservoir to an anode of a fuel cell, comprising the following steps: feeding hydrogen to the anode via a feed-pressure control unit; feeding oxygen or air to a cathode; periodically discharging a mixture which consists of a gas portion and a condensate, from the anode in a discharge cycle via a discharge line and a discharge-pressure control unit to a reservoir by periodically opening the discharge pressure control unit when the pressure prevailing in the reservoir is lower than the pressure in a feed means of hydrogen, the discharge cycle comprising the following steps: (a) increasing the pressure prevailing in the feed means of hydrogen above a desired value, (b) opening the discharge-pressure control unit for discharging the mixture to the reservoir when the increased pressure is achieved, (c) maintaining the increased pressure prevailing in the feed means of hydrogen during discharging of the mixture to the reservoir so that the pressure in the reservoir is increased, collecting and separating the mixture in the reservoir into a gas portion and a condensate; feeding the gas portion back to the anode without the use of a hydrogen pump, the step of feeding the gas portion back comprising the following steps: i. closing the discharge-pressure control unit and the feed-pressure control unit when a difference between the pressure in the anode and the pressure in the reservoir reaches a preset minimum level; ii. thereafter opening a feedback-pressure control unit connected to a feedback line when the pressure in the anode drops to a pre-set threshold level, whereupon hydrogen in the reservoir is fed back in the feedback line to the anode without the use of a hydrogen pump, due to the pressure difference between the reservoir and the anode; and iii. closing the feedback pressure control unit and opening the feed pressure control unit when the pressure in the reservoir drops to a desired value.