Publications Details

Time-resolved laser-induced incandescence measurements of particulate emissions during enrichment for diesel lean NOx trap regeneration

Laser-induced incandescence is used to measure time-resolved diesel particulate emissions for two lean NOx trap regeneration strategies that utilize intake throttling and in-cylinder fuel enrichment. The results show that when the main injection event is increased in duration and delayed 13 crank-angle degrees, particulate emissions are very high. For a repetitive pattern of 3 seconds of rich regeneration followed by 27 seconds of NOx-trap loading, we find a monotonic increase in particulate emissions during the loading intervals that approaches twice the initial baseline particulate level after 1000 seconds. In contrast, particulate emissions during the re-generation intervals are constant throughout the test sequence. For regeneration using an additional late injection event (post-injection), particulate emissions are about twice the baseline level for the first regeneration interval, but then decay with an exponential-like behavior over the repetitive test sequence, eventually reaching a level that is comparable to the baseline. In contrast, particulate emissions between regenerations decrease slowly throughout the test sequence, reaching a level 12 percent below the starting baseline value.