Exhaust Articles for Internal Combustion Engines

Abstract

Provided is a base metal undercoat containing catalyst and an exhaust article containing the catalyst. The catalyst contains a base metal undercoat with an oxygen storage component, and at least one catalytic layer. Also provided are methods for preparing the catalyst and methods for monitoring the oxygen storage capacity of an exhaust article containing the catalyst.

Description

[0001] This application is a divisional of U.S. application Ser. No. 09 / 968,192, filed Oct. 1, 2001, the contents of which is incorporated herein in its entirety.[0002] The present invention relates to exhaust articles and catalysts for the treatment of exhaust gases and methods for their use in on-board diagnostic systems. [0003] Three-way conversion (TWC) catalysts have utility in a number of fields including the treatment of exhaust from internal combustion engines, such as automobile and other gasoline-fueled engines. Emissions standards for unburned hydrocarbons, carbon monoxide and nitrogen oxides contaminants have been set by various governments and must be met, for example, by new automobiles. In order to meet such standards, exhaust articles containing a TWC catalyst are located in the exhaust gas line of internal combustion engines. The TWC catalysts promote the oxidation by oxygen in the exhaust gas of the unburned hydrocarbons and carbon monoxide and the reduction of nit...

AI Technical Summary

Benefits of technology

This approach enables the TWC catalyst to maintain efficient conversion of carbon monoxide and nitrogen oxides while allowing for adaptable OSC to meet different exhaust platform requirements, reducing the need for extensive reformulation and testing, and minimizing platinum group metal usage.

Problems solved by technology

As the TWC catalyst ages, however, its ability to store oxygen diminishes and the efficiency of the catalytic converter decreases.

Contemporary catalytic converters have a significant oxygen storage capacity (OSC) that dampens out the normal air / fuel cycling used in engine controller strategies.

Alteration of the OSC of typical catalysts, however, can alter the catalysts' characteristics including their conversion efficiency.

An increase or decrease in OSC to meet the OBD monitoring requirement can therefore be a burdensome process that can require multiple trials to finally arrive at the optimum OSC for a given exhaust system without sacrificing or altering catalytic efficiency or performance.

It is often the case that the final optimized formulation of a one catalyst that successfully meets the requirements of one exhaust platform having a specific OSC requirement, cannot be used for a different exhaust platform having a different OSC requirement without extensive reformulation and performance testing.

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