Tecogen Inc.
NOx reduction without urea using a dual stage catalyst system with intercooling in vehicle gasoline engines

Abstract:

An exhaust aftertreatment system includes a first catalytic converter, an oxidation catalyst including a storage catalyst, an air injector, and a cooling unit. The exhaust aftertreatment system is fluidly coupled to an output of a spark-ignited internal combustion engine that operates in the rich regime during acceleration and the lean regime during deceleration. In one aspect, the storage catalyst stores ammonia produced while the engine operates in the rich regime. The stored ammonia reacts with nitrogen oxide compounds produced when the engine operates in the lean regime. In another aspect, the nitrogen oxide compounds react with ammonia produced while the engine operates in the rich regime.