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38 E&MJ; • JULY 2014 www.e-mj.com Diesel Technology Update 2014 Engine suppliers are nearing the final stage of compliance with increasingly strict diesel emissions standards. One of their remaining challenges is to assure equipment OEMs and owners that new, cleaner-burning engines don't come with a big bump in installation or ownership costs. By Russell A. Carter, Managing Editor Diesel power is one of the core forces that drive mining progress, providing motive ener- gy for countless site activities. For a technol- ogy that's been around for nearly 125 years, it shows surprisingly few signs of age. Not that it hasn't evolved and matured steadily during its century-plus history, but over the past two decades, constant pressure to satis- fy increasingly stringent government-man- dated emissions—such as the U.S. Environ- mental Protection Agency's (EPA) Tier 1–4 and similar European Union Stage I–IV regu- lations—has resulted in a kind of facelift for this power platform, including the mid- to high-horsepower engine models used in min- ing, transforming them from the smoke- belching dinosaurs of the mid 20 th century to responsible corporate citizens today. This year marked a milestone in the diesel timeline as the Tier 4 Final emis- sions standards for off-highway engines rated at 174 to 751 hp (130–560 kW) became effective in January, sparking a steady stream of engine original equipment manufacturer (OEM) announcements of compliance with the new standards and setting the stage for a similar flurry of news in early 2015, when engines larger than 751 hp become subject to their own set of Tier 4 Final emissions standards. Each of the leading diesel OEMs for mobile mining equipment—Caterpillar, Cummins, MTU, Komatsu, Volvo Penta, Liebherr and others—has its own propri- etary approach for meeting the Tier 4 stan- dards. They all involve variations of four principal factors that govern diesel ignition and exhaust: fuel, air, electronic controls and aftertreatment. In many cases, the move from Tier 4 Interim to Tier 4 Final emissions control levels has required the addition of exhaust aftertreatment, but not much else in the way of deviation from man- ufacturers' proven Tier 4 Interim technology. From the OEMs' point of view, their emissions-control efforts have been highly effective: Cummins, for example, likes to point out that when Tier 4 Final controls are completely in effect, it would take 25 Tier 4 Final-compliant machines to pro- duce the same level of emissions generat- ed by just one equivalent Tier 1 machine. It hasn't been an easy task. Evelynn Sterling, technical director at Cummins Inc., told an audience at the 2013 World Mining Congress that, "…the 2014–2015 emissions regulations presented the most significant challenge to our customers' diesel-powered equipment design and operation in recent history." In fact, said Sterling, during Cummins' OEM and voice-of-the-customer surveys, operators told the company there were a number of engine design points that would be "nonnegotiable": • Power and performance must be main- tained or improved. • Total cost of ownership should be lower, with improved fuel efficiency. • Maintenance and durability must be maintained or improved. • Availability should be increased. • Engine service should be made easier. • Fewer turbochargers, not more. "We also heard 'no additional fluids!' but SCR (Selective Catalytic Reduction) requires Diesel Exhaust Fluid (DEF)," added Sterling. She pointed out that Cummins was able to draw from a deep pool of prior experi- ence when it came to diesel engine per- formance, having produced 1 million exhaust gas recirculation (EGR)-equipped and 650,000 diesel particulate filter (DPF)-equipped engines and 350,000 SCR systems, along with 3 million Variable Geometry Turbochargers (VGTs). As a com- Tier 4 Final architecture for Cummins'mid-range and heavy-duty engine range commonly used in mining includes Cooled Exhaust Gas Recirculation (Cooled EGR), plus Selective Catalytic Reduction (SCR). D I E S E L E N G I N E S EMJ_pg38-41_EMJ_pg38-41 7/2/14 3:26 PM Page 38