A fuel supply control system and method for a fuel cell are disclosed. The system includes: a fuel cell configured to receive a fuel gas and an oxidation gas and generate electric power; a recirculation line configured to circulate gas containing the fuel gas and connected to a fuel electrode of the fuel cell; a discharge valve provided in the recirculation line and configured to allow the gas to be discharged to the outside when open; a discharge amount estimator configured to estimate a discharge amount of the discharged gas based on a supply amount of the fuel gas supplied to the recirculation line, a consumption amount of the fuel gas consumed in the fuel cell, and a change in the amount of the gas in the recirculation line; an offset calculator configured to calculate the discharge amount of the gas estimated by the discharge amount estimator with the discharge valve closed, as a discharge offset; and a controller configured to control opening/closing of the discharge valve.

The present disclosure relates to a fuel cell system including: an air supply line configured to supply air to a fuel cell stack; a discharge line connected to the fuel cell stack and configured to guide exhaust gas discharged from the fuel cell stack; a discharge adapter connected to the discharge line and configured to discharge the exhaust gas to the outside; and a bypass line having one end connected to the air supply line and the other end connected to the discharge adapter, the bypass line being configured to selectively allow the air to flow from the air supply line to the discharge adapter, thereby effectively reducing a hydrogen concentration in exhaust gas discharged from the fuel cell stack.

A fuel cell system that generates electric power by supplying anode gas and cathode gas to a fuel cell includes a control valve adapted to control the pressure of the anode gas to be supplied to the fuel cell; a buffer unit adapted to store the anode-off gas to be discharged from the fuel cell; a pulsation operation unit adapted to control the control valve in order to periodically increase and decrease the pressure of the anode gas at a specific width of the pulsation; and a pulsation width correcting unit adapted to correct the width of the pulsation on the basis of the temperature of the buffer unit.

In order to improve estimation accuracy of a purging amount, a fuel cell system comprises a supply valve that controls a supply of an anode gas into an anode system, a purge valve that discharges an off-gas from the anode system, a pressure detecting unit configured to estimate or measures a pressure inside the anode system, and a purging amount estimating unit configured to estimate a purging amount of the off-gas discharged from the anode system through the purge valve based on a pressure change inside the anode system during a purge valve close duration in a supply valve open state and a pressure change inside the anode system during a purge valve close duration in a supply valve close state.

Methods and systems are described for optimizing water discharge in fuel cell vehicles. The system includes a fuel cell stack, a blower for purging water from the fuel cell stack and a controller. The controller detects that an ambient temperature satisfies a threshold temperature. The controller determines the fuel cell vehicle is approaching a stopping location. The controller calculates a water discharge time prediction necessary to purge excess water from the fuel cell stack while the fuel cell vehicle is operating in response to detecting that the ambient temperature satisfies the threshold temperature and the fuel cell vehicle is approaching the stopping location. The water discharge time prediction is calculated based on the blower operating while the fuel cell stack is in at least one of an idle state and a stopped state as the fuel cell vehicle approaches the stopping location.

A fuel cell system (200), wherein the fuel cell system (200) has: a) a fuel cell stack (10), b) an anode gas path (20) which fluidically communicates with the fuel cell stack (10) and which serves for supplying anode gas from an anode gas store (22) to the fuel cell stack (10), c) a cathode gas path (30) which fluidically communicates with the fuel cell stack (10) and which serves for supplying cathode gas from a cathode gas store (32) to the fuel cell stack (10), d) a cooling fluid path (40) which fluidically communicates with the fuel cell stack (10) and which serves for supplying cooling fluid from a cooling fluid store (42) to the fuel cell stack (10), e) a vibration generator (60) which is in data-transmitting communication with a control unit (50) and which serves for setting the fuel cell stack (10) into a vibrating state, and f) the control unit (50) for actuating the vibration generator (60) in order to set the fuel cell stack (10) into the vibrating state by means of the vibration generator (60).

The invention relates to a method for deactivating a fuel cell system (10) comprising a jet pump (28) for conveying an anode-side gas flow in a recirculation path (26), wherein the jet pump (28) comprises a metering valve (36) for metering H.sub.2. While the fuel cell system (10) is cooling, a flow passes through a drive nozzle (46) at least once in order to discharge condensed water. The t invention additionally relates to a jet pump (28) comprising a metering valve (36) and to the use of the method in order to deactivate a fuel cell system (10).

A fuel cell system includes a fuel cell stack, a reaction gas supply portion, and a control unit. The control unit performs two stages of purging that are a first purging and a second purging in which the flow rate of the reaction gas is smaller than the flow rate of the reaction gas of the first purging, and provides a purging standby time between the first purging and the second purging, and in a case in which an operation mode of the fuel cell stack when power generation of the fuel cell stack is stopped is a high output mode in which an output is higher than the output of a normal mode, the control unit makes a purging time longer than the purging time of the first purging that is performed in the normal mode.

System for recirculating hydrogen in a fuel cell including a tank having an inlet connectable to an outlet of the fuel cell and an outlet connectable to a line for feeding hydrogen to the fuel cell; the recirculation system includes a first check valve and a second check valve; the first check valve can be inserted between the outlet of the fuel cell and the inlet of the tank, for adjusting a flow from the fuel cell to the tank whilst the second check valve can be inserted between the outlet of the tank and the hydrogen feed line, for adjusting a flow of hydrogen from the tank to the feed line.

A braking control unit of a fuel cell vehicle is configured to, in a period during which the fuel cell vehicle is being braked in response to a braking request, (i) when an estimated amount of stagnant water is less than a predetermined second water amount less than a first water amount, limit an upper limit electric power of a regenerated electric power resulting from regenerative operation to a predetermined first value or below, and (ii) when the estimated amount of stagnant water is greater than or equal to the second water amount, execute an upper limit changing process of setting an upper limit electric power to a second value lower by a predetermined value than the first value.