Issue link: http://read.dmtmag.com/i/671314
|Tomorrow's Trucks | 8 www.studentdriverplacement.com May '16 drive fuel effi ciency while also creat- ing more NOx. "How can you do that and have better fuel economy? You can't get the best of both worlds. You have to make compromises." Golden says potentially higher tem- peratures will likely lead to demands on catalyst suppliers to increase ef- fi ciencies without making the systems necessarily larger. "I don't have more space," he says. "I have a box and I have all these things in the box. I need to get much more effi ciency from those compo- nents now if I'm going to map out a pathway to better CO2 emissions." There is also the wildcard that the needs of the market could outpace the demands of the government. "We are enjoying very low fuel pric- es right now, and we don't know how things may change in three or four years," says Mario Sanchez-Lara, Cummins' director of on-highway marketing communications. "That could bring pressure to deliver ef- fi ciency gains faster just because our customers would like to be able to remain as profi table as they are today but operating with a higher cost of fuel. I think the 4 percent we have to deliver, we know how to do it. We're very comfortable. We have a proven record of meeting the requirements over the last 15 years, but I wouldn't be surprised if we end up doing more than that because of the nature of the industry and what's going on with fuels and just competitive pressure." There's also the consideration that once OEMs hit the 2027 benchmark, the EPA is likely to continue its push for improvement. "I don't know what's out there be- yond Phase II for sure, but we know [CARB] is talking about a lower NOx standard that they need to be able to meet the federal ambient air quality standards for ozone," Yeager says. "So they're talking about possibly new NOx standards for heavy duty engines, and they're throwing out numbers as low as .02 compared to the .2 gram NOx that we're at today. So, another 90 percent reduction." The potential of another 90 percent reduction of NOx would pose one of the biggest challenges for engineers to-date, according to Golden. "If I have a more effi cient engine, it's hotter and I have more NOx and that increases the cost of my after treatment system for NOx," he says. "If I get lower CO2 with a higher combustion temperature, I'm going to have more NOx." "Wanting to maintain the effi ciency gains on the engine that we've made over the past years, it would be a challenge to go to a lot lower on NOx," Yeager adds, "but we need to do some research and we need to do some work on what those tradeoffs are and what would be the costs as- sociated with a new NOx standard, what the technologies are and that kind of thing." ◆