Sulzer Hexis Ag

Hexis Ag

Philip Holoch

Thomas Gamper

Alexander Schuler

John Schild

Markus Jenne

Andreas R&uuml;egge

Andreas Rüegge

A lambda probe in which a measuring point for oxygen in a sensor is connected via a diffusion gap with a reaction chamber. The reaction chamber drives oxygen along the diffusion gap. A desired oxygen partial pressure is set in the reaction chamber. The pump current, which is proportional to the strength of the stream of oxygen driven along the diffusion gap, can be used as a measurement for the partial pressure of the residual oxygen in the exhaust gas during a normal operating phase. The lambda probe can be operated for test purposes intermittently in a high or low phase, in which the oxygen partial pressure in the reaction chamber is a minimum or maximum value. While changing between the operating phases, by comparing the pump currents with empirical values, conclusions with regard to the ability of the probe to function can be derived.

Measuring method for monitoring residual oxygen in an exhaust gas

The fuel cell battery () has an integrated heat exchanger () which is arranged between a heat insulating jacket () and a stack () of high temperature fuel cells (). There is a chamber (), preferably at least two chambers for afterburning, between a periphery () of the cell stack and the heat exchanger. The heat exchanger is provided for a heat transfer from an exhaust gas () to a gaseous oxygen carrier (). There are arranged on the stack periphery (), outside or inside the chamber or chambers respectively, inlet points () for the oxygen carrier, on the one hand, and outlet points () for non-converted educts, namely a fuel gas () and the oxygen carrier, on the other hand. The heat exchanger () includes a passage system () through which the exhaust gas () and the oxygen carrier () flow largely in transverse planes disposed perpendicular to the axis of the cell stack () in one operating state of the battery. The exhaust gas can be led off through axially directed collecting passages (&#x2033;) which are arranged in a peripheral region of the heat exchange. Parts of the heat exchanger, which are disposed between the peripheral region and the cell stack, form a shield for screening the cell stack from the collecting passages with respect to a thermal influence.

Fuel cell battery with an integrated heat exchanger

The method for the operation of fuel cell battery ( ) comprises a control system ( ), through which the electrochemical reactions in cells ( ) of the battery are influenced. Gaseous flows ( ) of two educts (A, B) are fed into the battery in a controlled manner in a conditionally predetermined ratio of quantities and are passed through the cells separately. The first educt (A) contains oxidizing components, the second educt (B) contains reducing components and the first educt is in particular ambient air. The educt flows ( ) are united after passage through the cells and are further treated by means of an afterburning process and with the production of a flow ( ) of exhaust gas (C), so that at the conditionally predetermined ratio of quantities the reducing components are completely oxidized. The first educt flow, in particular the air flow, is variable through the control system to a limited extent; it is used for a regulation of the reaction temperature. Simultaneously to the regulation of the reaction temperature the second educt flow is held constant, namely by means of a second regulation ( ) which acts on one of the educt flows upstream of the battery inlet ( ).

Method for the operation of a fuel cell battery comprising a control system

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Winterthur, Switzerland

Philip Holoch