Palladium catalyst pre-oxidation to reduce light-off temperature
AssigneeFord Global Technologies, LLC
InventorRobert Walter McCabe
Life of this patent
Estimating the term…
Abstract
The invention is a method for preconditioning a palladium containing automotive catalyst by subjecting the catalyst to oxidation by means of an oxidizing gas containing at least 0.85% oxygen at a temperature of at least 450° C. preferably for at least 15 seconds. This oxidation can be carried out before or after engine shutdown. The catalyst is placed in the exhaust system in a location whereby the catalyst attains this temperature during steady state warm-up operation of the engine.
Claims9
A method for lowering the light-off temperature of a highly loaded palladium-containing three-way automotive vehicle catalyst during cold-starting of the vehicle engine, which method comprises the steps of:
- providing said palladium-containing catalyst comprising at least 100 g palladium/ft3 catalyst support material as the only catalyst in the exhaust system of an automotive vehicle at a location where the steady state warmed up operating temperatures of said system are at least 450° C., and
- subjecting said catalyst, after shutdown of said engine, to a flow of an oxidizing gas containing at least 0.85 volume % oxygen for a selected period of time while said catalyst is at an elevated temperature of at least 450° C. in order to oxidize said catalyst,
- whereby the light-off temperature of the palladium-containing catalyst is lowered.
Dependencies are inferred from the claim text.