Technique for production of ammonia on demand in a three way catalyst for a passive selective catalytic reduction system

Abstract

A method for controlling a powertrain includes selectively initiating an ammonia generation cycle, including injecting fuel into a combustion chamber of an engine before a primary combustion event to a calibrated air fuel ratio in a range lean of stoichiometry based upon generation of NOx within the combustion chamber, injecting fuel into the combustion chamber after the primary combustion event based upon an overall air fuel ratio in a range rich of stoichiometry and resulting generation of molecular hydrogen, and utilizing a catalyst device between the engine and a selective catalytic reduction device to produce ammonia.

Description

technical field [0001] The present invention relates to NO in internal combustion engines X Control of aftertreatment of emissions. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. [0003] Emissions control is an important factor in engine design and engine control. Nitrogen oxide NO X is a known by-product of combustion. NO X Produced by the splitting of nitrogen and oxygen molecules present in the engine intake air at high combustion temperatures, NO X The rate of formation has a known relationship to the combustion process, e.g. higher NO X The rate of formation is associated with higher combustion temperatures and longer exposure of air molecules to higher temperatures. NO produced during combustion X reduction and NO in exhaust aftertreatment systems X Management is a priority in vehicle design. [0004] Once generated in the combustion chambe...

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Problems solved by technology

Urea storage and replenishment can be difficult to maintain

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