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:
Apr. 13, 1993
Filed:
Dec. 23, 1991
Walter T Symons, Davison, MI (US);
Richard F Beckmeyer, Clarkston, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A catalyst for treatment of exhaust emissions from diesel engines includes a washcoat layer with a catalytically active metal. The washcoat layer has refractory oxide particles with catalytically active metal particles dispersed thereon, and colloidal silica disposed in a thin layer over the refractory oxide and metal particles. The refractory oxide particles and colloidal silica are each characterized by respective surface charges at a selected pH to cause the colloid to form the layer over the refractory oxide and metal particles. Preferably, the pH is selected to provide opposite and attractive surface charges between the colloidal silica and the refractory oxide particles. Preferably, the metal particles are at least one of the group consisting essentially of platinum, palladium, rhodium, ruthenium, copper and chromium.