Fleet Management News & Business Info | Commercial Carrier Journal
Issue link: http://read.dmtmag.com/i/667099
commercial carrier journal | april 2016 63 O ver the last 15 years, the diesel engine has under- gone an impressive evolution. According to the U.S. Environmental Protection Agency, transportation sources emitted 29 percent of all greenhouse gas emissions in the United States in 2007 and have been the fastest-growing source of GHG emissions in the country since 1990. Heavy-duty vehicles are the fastest-growing contributors to GHG emissions, EPA adds, with Class 7 and 8 combi- nation tractors and their engines accounting for roughly two-thirds of total GHG emissions and fuel consumption from the heavy-duty sector. EPA rang in the new millennium with an event horizon for diesel engine emissions and mandated that, effective with the 2007 model year, exhaust emissions spewing from on-highway truck engines be reduced by more than 90 percent. Also beginning with the 2007 model year, all on-road diesel heavy-duty engines were required to be outfitted with a diesel particulate filter, and another 50 percent of engines required nitrogen oxide exhaust control technology. By the 2010 model year, all on-road heavy-duty diesel engines were required to have NOx exhaust control technology. The beginning of an era Commonly referred to as EPA 2010, these new government emissions standards focused on reducing pollutants, NOx and particulate matter coming from heavy truck engines to 0.2 gram per brake horsepower hour for NOx and .01 for PM. Dr. Steve Golden, chief technology officer for Clean Diesel Technologies Inc., says EPA 2010 – regardless of what engine makers did to the engine itself to get within compliance – forced the use of selective catalytic reduction. "Once you got to 2010, everyone had to have every single cata- lyst component you could possibly think of," Golden says. "Now you see these incredibly complex systems in terms of emissions control do a very high NOx conversion and a very high emis- sions conversion in the same system." "[2010] kind of marked the era of SCR," says Mario Sanchez- Lara, Cummins' director of on-highway marketing communica- tions. "Really, 2010 was the time when all the aftertreatment that we needed was finally added to the engine system." Sanchez-Lara says EPA 2010 also helped Cummins focus its attention more intently on SCR solutions, which had begun to emerge as the most cost-effective and fuel-efficient emissions control technology. "SCR brought with it some fuel economy gains, as we were able to not have to work on the NOx control within the engine and we were able to dial back the EGR (exhaust gas recircula- tion)," he says. "That really helped us." At the time, EPA estimated that the proposed 2010 standards would add about $1,200 to $1,900 per new vehicle, but Golden says it was likely significantly more – not including additional maintenance. "Just looking at all the components, I'd say it's about $10,000 if you take all the controls, not just the catalyst com- ponents," he says. What's next for heavy-duty emissions controls? BY JASON CANNON