DETERMINATION OF THE LAMBDA VALUE OF REFORMATE WITH THE AID OF A FUEL CELL

摘要

The invention relates to a method for determining the lambda value (?_ist) of reformate (10) that is supplied to a fuel cell stack (12). In said method, the no-load voltage (U_o) in at least one fuel cell element (14) is detected and evaluated to determine the lambda value (?_ist). According to the invention, the at least one fuel cell element (14) is a terminal fuel cell element of the fuel cell stack (12) that is provided exclusively for measuring purposes, and the voltage provided for at least one consumer (34) can be tapped in the remaining fuel cell elements (36) of the fuel cell stack (12). The invention also relates to a method for controlling the lambda value in a reformer, to a device for determining the lambda value, to a system (32) comprising a reformer (16) for converting at least fuel (20) and air (22) into reformate (10) and to a fuel cell stack (12) that can be supplied with reformate (10) by the reformer (16), the lambda value in said reformer (16) being controlled.