http://www.epa.gov/EPA-AIR/1999/May/Day-13/a11383.htm
this is quite good reading, maybe later i will summarize it, but fuel will be down to 50 ppm for sulphur, but the engine folks have quite a unique phase in structure.
A. Current Diesel Fuel Requirements in the U.S.
EPA set standards for diesel fuel quality in 1990 (55 FR 34120,
"August 21, 1990). These standards, effective since 1993, apply only to
fuel used in highway diesel engines. The standards limit the sulfur
concentration in fuel to a maximum of 500 ppm, compared to a pre-
regulation average of 2500 ppm. They also protect against a rise in the
fuel's aromatics level from the then-existing levels by setting a
minimum cetane index of 40 (or, alternatively, a maximum aromatics
level of 35%). Aromatics tend to increase the emissions of harmful
pollutants. These regulations were established in response to a joint
proposal from members of the diesel engine manufacturing and petroleum
refining industries to reduce emissions and enable the use of catalysts
and particulate traps in meeting EPA's PM standards for diesel engines.
As a result of our diesel fuel regulation, highway diesel fuel sulfur
levels average about 340 ppm outside of California.<SUP>18</SUP> Alaska
has an exemption from our existing 500 ppm limitation (permanent in
some areas, temporary in others) and is currently seeking a permanent
exemption for all areas of the state, because of special difficulties
in supplying lower sulfur diesel fuel for that market (63 FR 49459,
September 16, 1998). Similarly, American Samoa and Guam also have
permanent exemptions from our existing 500 ppm limitation (July 20,
1992, 57 FR 32010 and September 21, 1993, 58 FR 48968). We currently do
not regulate diesel fuels that are not intended for use in highway
engines. Diesel fuel sold for use in most nonroad applications such as
construction and farm equipment has sulfur levels on the order of 3300
ppm.<SUP>19</SUP>"
"B. Diesel Sulfur Changes in Other Countries
Progress toward diesel fuel with very low sulfur levels has
advanced rapidly in some parts of the world. The European Union's
``Auto Oil Package'' was adopted recently in an effort to improve air
quality, by establishing an integrated approach to setting requirements
for fuels in such a way that vehicles can produce their best
environmental performance.<SUP>20</SUP> As part of the Auto Oil
Package, the European Union adopted new fuel specifications for diesel
fuel.<SUP>21</SUP> These specifications contain a diesel fuel sulfur
limit of 50 ppm by 2005, with an interim limit of 350 ppm by 2000. The
Member States will be required to monitor fuel quality to ensure
compliance with the specifications."
"In the United Kingdom, the entire diesel fuel supply soon will be
at sulfur levels of 50 ppm, based on recent announcements by major
refiners.<SUP>22</SUP> The United Kingdom currently offers a two-penny
tax break for diesel fuel. Finland and Sweden also have tax incentives
encouraging low sulfur diesel fuel. Finland's tax incentive applies to
diesel with sulfur levels below 50 ppm, which accounts for 90% of the
Finnish market.<SUP>23</SUP> Sweden's tax incentive applies to diesel
with sulfur levels below 10 ppm.<SUP>24</SUP>"
"
1. Technologies Improved By Sulfur Reduction
Technologies that may derive benefit from diesel fuel
desulfurization include cooled EGR, lean-NO<INF>X</INF> catalysts, PM
filters, oxidation catalysts, and selective catalytic reduction (SCR).
None of these technologies appear to have a threshold low sulfur level,
above which the technology is simply not viable. Rather, every degree
of sulfur reduction would provide correspondingly greater latitude for
engine or aftertreatment designers to target their designs for
aggressive emission reductions."
"The application of electronically controlled EGR to diesel engines
is an effective means of controlling NO<INF>X</INF> emissions. Cooling
the recirculated exhaust gas before it reenters the combustion chamber
can greatly increase EGR efficiency. NO<INF>X</INF> emissions
reductions of up to 90% are believed possible with cooled EGR systems
for heavy-duty diesel applications.<SUP>27</SUP> However, manufacturers
have claimed that one of the primary limiters on how extensively cooled
EGR can be used is the potential for condensation of sulfuric acid and
associated corrosion-related durability problems""Acid aerosol formation may also increase the frequency of oil changes due to increased acidification of engine lubricating oil. Any actual oil acidification problem may be addressable by increasing alkaline oil additives, and corrosion-resistant materials are available for durable EGR cooler construction"
"These catalysts include two types: (1) Active catalysts
require a post-combustion fuel injection event and (2) passive
catalysts require no post-injection."
"cooled EGR. Lean-NO<INF>X</INF> catalysts are
prone to long-term efficiency loss due to sulfur-induced deactivation
or ``poisoning''"
"One method of exhaust aftertreatment for controlling diesel PM
emissions is to pass diesel exhaust through a ceramic or metallic
filter (sometimes called a ``soot filter'' or ``PM trap'') to collect
the PM, and to use some means of burning the collected PM so that the
filter can be either periodically or continuously regenerated. Filter
designs have used catalyzed coatings, catalytic fuel additives,
electrical heating, and fuel burners to assist trap regeneration.
Failure to consistently regenerate the filter can lead to plugging,
excessive exhaust back-pressure, and eventually overheating and
permanent damage to the filter. Inconsistent regeneration due to the
low frequency of adequately high temperature exhaust transients has
been a particular problem in applying PM filters to light-duty diesel
vehicles. Although PM filters have been used with current fuels, some
designs, especially those that use catalyst materials susceptible to
sulfate generation, can be made more effective with lower sulfur fuel.
In addition, some PM filter system concepts may require low sulfur
fuel, as discussed below."
"Manufacturers have claimed that lower sulfur fuel will improve the
durability of engines and emissions controls, and will reduce the need
for maintenance, including oil changes. These benefits would produce a
cost savings to vehicle owners. They may also produce an indirect
emissions benefit because, although manufacturers must take steps to
ensure durable emissions controls (such as providing warranties and
assuming liability over a set useful life), many engines may have high
emissions because they last well beyond the regulatory useful life or
because they are poorly maintained."
"Furthermore, fuel changes may inadvertently and
detrimentally alter fuel system components such as o-ring seals, and
may also reduce the helpful lubricating effect that some sulfur
compounds have on fuel system components, although it also appears that
steps can be taken to preclude these effects, such as the use of
lubricity additives"
So it may not be the ability to run low sulphur fuel, but the ability to control the emissions equipment ?
ford is still flipping on the 6.4 intro so i wouldnt expect to see it in a pickup till jan or mar of next year as an early 2008,
if your ready and got th e$$$ by now and let the new enginse run a few years under th newer rules.
dodge and gm are all in the same boat, should be an interesting next few years.
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