MMT fuel-borne catalyst could offset problem of phosphorous, sulfur in lube oil

Diesel Fuel News, Sept 15, 2003

MMT Fuel-Borne Catalyst Could Offset Problem Of Phosphorous, Sulfur In Lube Oil: Even while oil blenders and engine makers debate tolerable levels of sulfated ash, phosphorous and sulfur (SAPS) in lubes for catalyst-equipped, 2007-compliant diesel engines, the manganese-based MMT fuel-borne catalyst (FBC) could effectively scavenge phosphorous and sulfur from NOx traps, Ethyl researcher David Human showed here.

"This could offset the phosphorous and sulfur in lube oil, as these are best for wear/oxidation prevention" in engines, he said. The sulfur-scavenging also could effectively double NOx trap performance over its lifetime, compared to ordinary ULSD fuel. MMT FBC also reduces the "balance point" temperature for soot oxidation in a catalyzed diesel particulate filter (DPF) by 22[degrees]C versus ordinary ULSD. MMT also accelerates DPF soot oxidation time dramatically, thus reducing backpressure, as shown in tests on a Cummins 5.9 liter engine. At equal metal treat rates, MMT accelerated soot oxidation (and lowered backpressure) faster than cerium, cerium/platinum, ferrocene, and cerium/iron. Nor was there any MMT slip past the DPF, in tests of 3-, 10- and 20-ppm treat rates. While MMT would add more ash to the DPF, what ash remains is "looser and fluffier" hence easier to remove, he said. As for impact of MMT addition on DPF ash-cleaning frequency, that hasn't been determined as engine tests so far have only covered about 15,000 miles.