11 October 2008
Miratech Corporation announced a new integrated diesel oxidation catalyst (DOC) exhaust manifold kit, designed to allow operators of diesel locomotives and marine vessels to meet EPA Tier 0, 1, and 2 emission standards.
Dubbed V-CAT™, the catalyst/exhaust manifold system addresses a number of engineering challenges which have hampered previous emission control efforts in the locomotive application, as described in the US Patent #7,412,824. The major challenges when designing a DOC for use in EMD locomotives include limited space behind the turbocharger; exhaust gas temperatures that are too low for effective DOC performance; and the risk of increasing the exhaust backpressure. In the V-CAT design, the catalyst is integrated directly into the exhaust manifold, thereby keeping open access to all areas—including the EMD overhead area—needed for regular service and maintenance. Integrating the V-CAT into the exhaust manifold, upstream from the turbocharger, also addresses the issue of low exhaust gas temperatures.
In order to substantiate its performance, the manifold system has been applied to an in-use 2,850 kW diesel freight locomotive owned by Union Pacific. After installation, emissions were tested by Southwest Research Institute (SwRI). The V-CAT-equipped locomotive started operating in revenue service in October 2006, with SwRI monitoring real world performance via a wireless system that uploads data to the internet every six-minutes. The DOC system was replaced in April, 2008 with an improved design and is back in revenue service. SwRI’s tests with 15 ppm sulfur fuel showed PM emission reductions of over 50%; a 60% reduction of HC emissions; and a 90% reduction in CO emission, without a sacrifice in fuel economy or NOx emissions.
The V-CAT design feature removable, square catalyst elements, each of which utilizes the Ecocat VORTEX™ substrate. The V-CAT manifold kit is designed to replace existing manifolds on EMD 710, 645 and 567 roots-blown or turbocharged engines.