Robert Boschgmbh

Bernhard Bloemer

Bernd Schumann

Carsten Springhorn

Detlef Heimann

Rainer Strohmaier

Margret Schuele

Bernd Mueller

Thomas Brinz

Harald Neumann

Thomas Wahl

Hans-Joerg Renz

Thomas Moser

Sabine Thiemann-Handler

A sensor element and a method for determining the concentration of at least one gas component, especially of a nitrogen oxide, in a gas, mixture. For this purpose, the sensor element includes at least one first electrode exposed to the gas component to be analyzed and at least one reference electrode, which are electrically interconnected by a first solid electrolyte. Furthermore, an electric current between the first electrode and a further electrode is measured continuously or in sampling fashion in response to the application, especially the setting, of an electric voltage between first electrode and the reference electrode due to a chemical reaction proceeding at the first electrode, by which the concentration of the gas component to be analyzed in the gas mixture can be determined. During this process, the application or setting of the electric voltage takes place only during recurring time intervals. In addition, the electric current between the first electrode and the further electrode is measured at least intermittently within the recurring time intervals.

Gas sensor element and method for determining the concentration of a gas component in a gas mixture

A method for operating a mixed-potential exhaust-gas probe for an internal combustion engine having a heatable probe ceramic with a first electrode , which is arranged in a chamber and is subjected to the reference atmosphere and with a second electrode which detects gas molecules and is arranged in the exhaust gas of the internal combustion engine, a pump voltage being applied between the first and second electrodes by means of a pump voltage source, so that, in the interior of the chamber , a somewhat reduced oxygen partial pressure is adjusted by the electrochemical pumping off of the oxygen molecules, characterized in that one applies a constant external voltage to the electrodes ( ) with this voltage deviating from the thermodynamic equilibrium voltage of the wanted reaction, measuring and evaluating the current dropping across the electrodes ( ).

Methods for operating a mixed potential exhaust sensor and circuit configurations for carrying out said method

An electrochemical gas sensor for determining the concentration of gas components in a gas mixture, in particular for determining NOx and HC. The gas sensor includes a first measuring gas space which is connected to the measuring gas, and a second measuring gas space which is connected to the first measuring gas space by a connecting channel. Furthermore, a first electrode and a second electrode, arranged in the first measuring gas space, and at least one third electrode arranged in the second measuring gas space, and at least one fourth electrode are provided. The two measuring gas spaces are arranged in layer planes on top of one another and are separated from one another by at least one oxygen ion conducting layer, the connecting channel passing through the oxygen ion conducting layer.

Electrochemical gas sensor

A sensor for determining gas components and concentrations in a gas mixture that is particularly suitable for analyzing HC, NO and CO in exhaust gases of internal combustion engines in the sensor, an outer electrode, that is separated from an MO electrode by an electrolyte layer, is applied on a substrate. In this context, the outer electrode and the MO electrode are in communication with the gas mixture to be analyzed. In addition, the outer electrode contains a region that is in contact with a gas-permeable tunnel layer which in turn contains a region that is directly exposed to the gas mixture to be analyzed, so that the gas to be analyzed can be supplied to the outer electrode via the gas-permeable tunnel layer.

Sensor for analyzing gases

A gas sensor in the form of a mixed-potential sensor in which the influence of temperature-dependent interference is reduced. An improved temperature control is provided with the help of a temperature sensor mounted on the surface of the electrolytic substrate.

Gas sensor

A method of operating a gas sensor having two sensor electrodes whose output signal is evaluated in an evaluation circuit connected downstream of the sensor electrodes, the sensor electrodes being arranged in an ion-conducting ceramic and being therefor heated by an electrical heater, characterized in that a pulsewidth modulated heater voltage signal is applied to the heater; and that a compensation signal is superposed on the output signal of the sensor electrodes, the compensation signal being essentially formed so as to be counterclocked and inverted to the pulsewidth modulated heater voltage signal.

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Stuttgart, Germany

Bernhard Bloemer