The Urea Blues

My blog about Cummins' flip-flop on using selective catalytic reduction (SCR) and urea in its 2010 heavy-duty diesels has spurred some interesting comments about urea, the mysterious blue liquid that will soon become as much a part of the heavy trucking industry as EGR and DPF have. A few of those concerns I can comment on here, but a few will have to remain open questions until we have some real-world experience with urea. Going back to the conference call in which Cummins announced its new product plans, there were a lot of questions about urea, and a lot of tacit admissions that using urea in heavy trucks may not be a walk in the park. Back when Cummins had previously announced that it would only use an SCR/urea system in its medium-duty product, company executives explained that the system was well-suited to the medium-duty market because those vehicles traditionally returned to home base after completing their duty cycle, and therefore it would be easy for fleets to maintain urea levels in the trucks. Heavy-duty engines, not so much, according to Cummins execs. Of course, with Cummins' new plans that argument has gone up in a puff of smoke, so to speak, and so those same execs, two weeks ago, were suddenly being asked to address certain sticky questions about urea. One was about the rising cost of urea, which, one reporter claimed, could cost just as much as diesel fuel by the time 2010 rolls around. Cummins' reply was that even if urea does cost that much, "there are cost benefits" in the form of a potential five percent improvement in fuel economy. Another question concerned the frequency with which urea tanks would need to be refilled, to which Cummins responded that a two- to three-week interval would be "typical" for a Class-8 truck. Ok, that may be a reasonable time frame, but if the urea refilling doesn't sync with filling the fuel tanks, how many mistakes are going to be made? Now, I want this urea system to work, because... well, because it has to. But there are a lot of questions, and, in truth, none of the answers that engine OEM execs have been coming up with are completely reassuring to me, and I doubt that they will be to most fleet maintenance managers. Do they reassure you?

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