SCR looks more viable as 2010 solution: Experts

NEW YORK — Some of the barriers to making SCR (Selective Catalytic Reduction) the 2010 emissions solution of choice are falling in North America, according to industry experts.

After discussions with stakeholders and officials from Cummins at a recent teleconference, analysts at New York-based transportation market firm Bear Stearns say that SCR is likely the engine technology to be used to meet upcoming EPA emissions regulations for 2010 since past concerns over availability are not the insurmountable hurdle that was first thought.

So far, engine manufacturers have been discussing two potential solutions: the use of particulate filters coupled with either NOX adsorbers, or SCR. Not only does the latter have a proven track record in meeting European emissions standards, but SCR could also carry a modest fuel economy benefit, Bear Stearns states in a follow-up report.

Incremental costs of SCR don’t figure
to be much of a hurdle for 2010

“It’s true that active DPFs using SCR technology utilizes a urea catalyst that
in many cases will need periodic replenishment. However, our call participants do not expect this to represent much of a stumbling block for SCR growth in (North America),” the firm explains. “The EPA’s primary concerns — that urea be widely available and that operators actually replenish the substance when they need to — is manageable.”

For example, Bear Stearns says, equipping 3 percent of truckstops in the U.S. would ensure access to urea for 95 percent of commercial vehicle highway driving miles. “Compared to the switch to ULSD … that occurred in 2006, the development of a urea infrastructure will be manageable.”

Furthermore, potential incremental costs of SCR also don’t figure to be much of a hurdle for implementation. In Europe, most incremental costs from
SCR systems have been covered by “annual vehicle price increases or cost reductions, so that the pricing difference is negligible to consumers.”

Unlike the first generation EGR engines of 2002, these new engines are expected to carry modest fuel economy gains. Because of the robustness of SCR aftertreatment in the reduction of NOx emissions, engines can be designed for higher NOx emissions, which “in turn causes hotter combustion but generally with more advanced timing comes a more efficient engine and lower diesel particulate emissions.”

In Europe, where carriers have reported fuel economy gains in the high single digits, SCR engines were designed to meet Euro 4 standards without a diesel particulate filter. However, because of different emissions benchmarks, North American manufacturers will have to use both a DPF (for diesel particulate matter) and SCR for 2010, meaning the industry will not likely see the same fuel economy improvements as in Europe.

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