Device and method for internal combustion engine control

摘要

A method is described for operating an engine coupled to an upstream and downstream emission control device that stores and reacts oxidants such as NOx. The method transitions from lean to stoichiometric or rich operation under various conditions. The amount of fuel used during the stoichiometric or rich operation is minimized by using an upstream three-way catalyst primarily used for NOx storage, and a downstream three-way catalyst primarily used for oxygen storage.