"With each threshold where we have hit lower emissions standards, there has been a penalty in terms of fuel efficiency," says Kilfin. He estimates that following the 2007 standards, the total loss of fuel efficiency was in the range of 5 percent to 8 percent. Emission reduction devices increased trucks' weight and the overall technology added several thousand dollars to the price of new vehicles, he says.
With the final 2010 regulations, emissions will contain a maximum of 1 gram of nitrogen oxide or NOx and a particulate output of .01. This compares with 5 grams of NOx and a 1.1 particulate output in 2001.
Two paths have been selected by engine companies to meet the 2010 standards, Kilfin explains. One is referred to as SCR or selective catalytic reduction and has been embraced by the majority of engine manufacturers. Navistar is taking a different approach, employing an advanced exhaust gas recirculation system.
Both systems appear to deliver substantial improvements in fuel economy over 2007 engines, Kilfin says. "By the time this is finished and has reached full development and maturity, I believe we will have regained 8 percent to 10 percent in fuel economy, which is significant."
The benefit overall is that these vehicles produce cleaner air, he says. "They also appear to offer benefits in terms of operational reliability, noise reduction and driver friendliness."
