|
THE NATIONAL
CLEAN BUS NETWORK
home || about ||
news || the
problem || solutions ||
clean bus fleets || links ||
comments
Engine
Certification Standards & Fuel Standards
fuels ||
technologies
|| regulation
Under the authority given
to it by the Clean Air Act, the Environmental Protection Agency (EPA)
sets standards for engine
technologies to protect human health within an "adequate margin
of safety."
On January 18, 2001,
the EPA published rules for new emissions standards to apply to
heavy-duty vehicles. The regulations apply to both diesel engines
and diesel fuel. It was necessary for EPA to treat both the engine
and the fuel at once since the quality of diesel fuel will affect
the performance of emission control devices necessary to meet the
new engine certification standards.
Previous Engine
Certification Standards (Model Year 2004+)
Manufacturers have
the choice of certifying their engines to one of the following
two standards
NMHC
+ NOx (combined non-methane hydrocarbons and nitrogen
oxides): 2.4 g/bhp-hr
or
NMHC
+ NOx with NMHC limit: 2.5 g/bhp-hr with 0.5 g/bhp-hr
limit on NMHC
New Engine
Certification Standards (Model Years 2007-2010+)
Engine
manufacturers must meet these engine standards beginning with
model year 2007. The implementation of the new standards will
span four years. For model years 2007 through 2009,
manufacturers must meet the NOx and NMHC standards with only
fifty percent of sales, but all new engines must meet the new
PM standard. By model year 2010, all engines sold must meet
all the new standards.
Nitrogen
Oxides (NOx) - 0.20 grams per brake horsepower-hour (g/bhp-hr)
Non-Methane
Hydrocarbons (NMHC) - 0.14 g/bhp-hr
Particulate
Matter (PM) - 0.01 g/bhp-hr
New Fuel
Standards
Beginning June 1,
2006, refiners must begin producing highway diesel fuel that
meets a maximum sulfur standard of 15 parts per million (ppm).
All 2007 and later model year diesel-fueled vehicles must be
refueled with this new ultra low-sulfur diesel fuel.
EPA provides
flexibility to refiners to make this transition easier. As a
result of banking and trading programs, temporary compliance
options, hardship provisions for small refiners and fuel
supply concerns, up to 25 percent of highway diesel fuel
produced between June 2006 and lasting through 2009 may
contain sulfur content of up to 500 ppm, the current fuel
standard. As a result, two diesel
types may be available for purchase until the end of 2009.
View the final
regulation at http://www.epa.gov/fedrgstr/EPA-AIR/2001/January/Day-18/a01a.htm
|
