In-Cylinder Regeneration of Lean NO{sub}x Trap Catalysts Using Low-Temperature Combustion

摘要

A Lean NO{sub}x Trap (LNT) regeneration method that has shown promise regarding its ability to effectively regenerate the LNT, while not adversely affecting the PM emissions, involves the use of Low-Temperature Combustion (LTC). LTC is accomplished by highly diluting the intake charge with EGR. If enough EGR is applied, the in-cylinder air:fuel mixture, and ensuing exhaust, will become rich, thereby regenerating the LNT. This type of highly dilute combustion tends to be more premixed than diffusion, which can lower engine-out PM and NO{sub}x emissions. LTC regeneration has been characterized and results are presented comparing this approach to other approaches for rich, in-cylinder diesel combustion for LNT regeneration.