A long breathing lean NOx trap for diesel after-treatment supplemental energy reduction

A long breathing strategy was investigated as a method for reducing the supplemental energy consumption of a diesel lean NOx trap (LNT). Empirical tests were performed on a heated flow bench set-up. The test results indicated that the LNT adsorption (breathing) time increased exponentially when the nitrogen oxide (NOx) level in the feed gas was reduced. Longer adsorptions led to supplemental energy savings due to less frequent LNT regeneration. In these tests, supplemental energy savings of over 70% were achieved with a long breathing LNT compared to a traditional LNT. Additional empirical tests investigated the concept of on-board hydrogen generation due to its potential benefits to an after-treatment system. The test findings revealed that the reformer temperature was a critical factor for on-board hydrogen generation. Further numerical and empirical tests revealed the benefits of utilizing a flow reversal system for hydrogen generation.