A panel of outside experts advising federal regulators about available technologies for improving fuel economy will include light-duty diesel engines in its final report.In an interim report made public today, the panel said developments in emission controls indicate that modern diesels will be able to comply with U.S. clean-air regulations.
The potential of diesel engines to reduce fuel consumption by as much as 30 to 40 percent over comparable gasoline engines justifies their inclusion on the list of available technologies, the interim report said.
The panel, working under the National Research Council, was asked by the National Highway Traffic Safety Administration to update a 2001 study of fuel-saving technologies.
Neither diesels nor hybrids were included in the landmark 2001 report, which served as a basis for rules that modestly raised light-truck fuel economy standards for the 2005-11 model years.
It also helped fuel the congressional debate that led to enactment in December of a new energy law. The measure calls for a 40 percent increase in car and truck standards, to a 35 mpg fleet average by 2020.
Diesels were left out of the earlier study because they could not meet clean-air standards. Hybrids, then considered a niche technology, also will be included in the new report.
But the panel said it must continue to concentrate on how to improve vehicles powered by gasoline engines, which still power " the vast majority of vehicles," the panel said.
The updated study will not deal extensively with all-electric or fuel cell vehicles because " the committee does not expect commercialization of fuel cell vehicles or widespread marketing of all-electric vehicles before 2020," the interim report said.
A final report is due by mid-2008. NHTSA must issue its first set of standards under the new energy law by April 1, 2009, effective for the 2011 model year.
The National Research Council is the administrative body for the National Academy of Sciences, the National Academy of Engineering and the Institute of Medicine.
The research council said the private, nonprofit institutions, collectively called the National Academies, operate under a congressional charter to provide expert advice to the federal government and public.