Method and storage container for determining a stored amount of ammonia for catalytic exhaust gas purification

US8991156B2 · kind B2 · utility

Assignee

• Bayerische Motoren Werke Aktiengesellschaft · DE

Inventors

• Ralf Widmann · Stuttgart, DE
• Thomas Baumeister · Munich, DE
• Andreas Bruhn · Puchheim, DE
• Udo Strathoff · Munich, DE

Key dates

• Filing date: Nov 10, 2011
• Grant date: Mar 31, 2015
• Expiry date: Nov 2, 2033

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method is provided for determining the amount of ammonia which is stored in a storage container by a chemical bond to a solid storage medium, in particular a salt of an earth alkaline metal or the like, and which can be released by supplying heat in order to be supplied to a catalytic exhaust gas purification device of an internal-combustion engine. The storage medium functions as a dielectric of an electric capacitor and the stored amount of ammonia is inferred from the capacity of this capacitor. One wall of the housing of the storage container functions as a first electrode of the capacitor, and, within the storage container, at least one additional electrode is arranged such that at least a partial amount of the storage medium forms the dielectric. The storage container may have an essentially cylindrical shape. Several cylindrical electrodes can be arranged in a coaxial manner.