The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 25, 2008
Filed:
Aug. 02, 2002
Rolf Reischl, Stuttgart, DE;
Rolf Reischl, Stuttgart, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
In a method and with a circuit for operating a nitrogen oxide sensor for determining the nitrogen oxide (NOx) concentration in a gas mixture, in particular in post-treatment of an automotive exhaust, an electric pumping voltage (U_APE,IPE) which induces a pumping current (I_pump) being applied between an internal pump electrode (IPE) and an external pump electrode (APE) of a pumping cell, by which a constant oxygen partial pressure is established in a first test gas space by pumping oxygen in or out, the pumping voltage (U_APE,IPE) being regulated so that a constant voltage value is established at electrodes of a concentration cell, a NOx-sensitive third electrode situated in a second test gas space being operated as the second pumping cell in which a limit pumping current is established, indicating the NOx concentration, in order to minimize the influence of oxygen on the nitrogen oxide signal measured, the pumping current (I_pump) is switched off or reduced in a controlled manner within a measurement time window (T_Mess) and the NOx concentration is determined within the measurement time window (T_Mess).