Abstract: The invention relates to a method of starting up a fuel cell system comprising a reformer (10) and a fuel cell stack (12), the reformer receiving during a first start-up phase a supply of oxygen and fuel with a first air ratio ?i characterizing the fuel/air ratio, the reformer receiving during a second start-up phase a supply of oxygen and fuel with a second air ratio ?2 characterizing the fuel/air ratio, the first fuel/air ratio ?1 being larger than the second air ratio ?2 (?1>?2) and the fuel cell stack receiving a supply of reformate (18) generated in the reformer during the first and the second start-up phase. In accordance with the invention it is provided for that the transition from the first start-up phase to the second start-up phase is monitored by sensing a voltage furnished by the fuel cell stack (12). The invention relates furthermore to a fuel cell system.

Abstract: The invention relates to a fuel cell system including a first heat exchanger via which cathode feed air can be supplied to a fuel cell or fuel cell stack and to which a mixture of afterburner exhaust gas of an afterburner and cathode exhaust air having materialized in the fuel cell or fuel cell stack can be supplied for heat exchange between the cathode feed air and the mixture via the first heat exchanger. In accordance with the invention it is provided for that a second heat exchanger is provided via which the cathode feed air can be supplied from the first heat exchanger to the fuel cell or fuel cell stack and via which the afterburner exhaust gas can be supplied to the first heat exchanger to form the mixture, in thus achieving a heat exchange between the afterburner exhaust gas and the cathode feed air.

Abstract: The invention relates to a reformer system for generating a hydrogen-rich reformate comprising a reformer to which fuel and an oxidising agent can be supplied. According to the invention it is contemplated that the fuel supplied to the reformer is at least partly coolable by a fluid having other functions in addition to the function of cooling the fuel in the reformer system or a parent system into which the reformer system is integrated. The invention further relates to a method for generating a hydrogen-rich reformate as well as a fuel cell system comprising a reformer system according to the invention.

Abstract: The invention relates to a method of starting up a fuel cell system comprising a reformer (10) and a fuel cell stack (12), the reformer receiving a supply of fuel (14) and air (16) as the starting materials and the fuel cell stack receiving a supply of reformate (18) generated by the reformer. In accordance with the invention it is provided for that the air ratio characterizing the fuel/air ratio of the starting materials supplied to the reformer (10) is varied as a function of a temperature of the fuel cell stack (12). The invention relates furthermore to a fuel cell system.

Abstract: The invention relates to a method for closed/open loop control of a total lambda value of a reformer (10) comprising at least a combustion zone (12) and an evaporation zone (14) connected to the combustion zone (12). In accordance with the invention for closed/open loop control of the total lambda value, closed loop control of the lambda value of the combustion zone (12) and open loop control of the fuel performance supplied to the evaporation zone (14) is provided. The invention relates furthermore to a system with a reformer (10) comprising at least a combustion zone (12) and an evaporation zone (14) connected to the combustion zone (12) and with a a controller (26) for closed/open loop control of a total lambda value.

Abstract: The invention relates to a reformer for a fuel cell system for generating a reformate comprising a plurality of function units for treating the fuel, at least one function unit being adapted to a first type of fuel. In this arrangement the invention is characterized to advantage in that the function unit adapted to the first type of fuel can be releasably coupled to the reformer as a module by means of an interface which is also designed to couple a replacement function unit instead of the function unit adapted to the first type of fuel, the replacement function unit being adapted to a second type of fuel different from the first type of fuel. The invention relates furthermore to a function unit for such a reformer, to a fuel cell system having such a reformer and to a motor vehicle having such a fuel cell system.

Abstract: The invention relates to a fuel cell system including a fuel cell stack (10), an afterburner (12) for combustion of exhaust gas emerging from the fuel cell stack and sited in an exhaust gas conduit of the afterburner a heat exchanger (16) in which cathode feed air (18) supplied to the fuel cell stack (10) can be heated. In accordance with the invention it is provided for that cathode feed air (20) can be supplied to the fuel cell stack (10) without being prior heated in the heat exchanger (16) and that the heat and temperature balance of the fuel cell stack (10) can be tweaked by the overall flow of the cathode feed air supplied as well as by the ratio of the proportions (18, 20) of the cathode feed air as heated in the heat exchanger and as not heated in the heat exchanger. The invention relates furthermore to a method of tweaking the heat and temperature balance of a fuel cell stack.

Abstract: System and process for producing a reformate to be supplied to a fuel cell stack, the system having a reformer (12) to which fuel (14), air (16) and the anode exhaust gas (18) of the fuel cell stack can be supplied to produce the reformate (10). The system has one or more devices (20) which at least partially oxidize the anode exhaust gas (18) before it is supplied to the reformer (12).