On Sun, 14 Oct 2007 17:44:23 -0400, in rec.autos.makers.vw.watercooled
(message <gc35h3d47ab40m7p5esiev9q59g1cebt97@4ax.com>), Al Rudderham
<xal.rudderhamx@sympatico.ca> wrote:

That is certainly the case in Canada; I don't know about the US.

At issue is the fuel that is available.  Briefly (and horribly
oversimplified), the older type of diesel fuel has some substances in
it that are incompatible with newer filter technologies.  Those filters
are what enable the diesels to achieve lower emissions than what
diesels have traditionally put out.  Europe has been making great
strides in diesel fuels for many years, but North America did not adopt
those standards.  For instance, the EU rule was a sulphur limit of 50
ppm by 2005, with availability of 10 ppm.  By 2009, only 10 ppm fuel
will be allowed for highway vehicles.  Canada would only guarantee
availability of < 500 mg/kg fuels as of Sept of this year, although 15
mg/kg fuel was available below the northern service area by last year.
Automakers have had to test only their old technologies, because with
the general availability of high-sulphur fuels (and no way to guarantee
someone couldn't accidentally fill up with them, causing expensive to
repair emission-control problems), automakers have been reluctant to
import their latest technology.  The result is that they can't pass the
current emissions limits using diesels, so they can't sell the engines.

Part of the reluctance in North America has been attributed to the
trucking industry, which didn't want expensive changes imposed.  Since
it was overwhelmingly a stronger diesel consumer than passenger cars,
it had a much greater say in the direction of the industry.  Whether
this is an accurate attribution is something I can't say, since I'm not
an industry person.

Note that the older diesels _don't_ get all the emissions benefits of
the new fuels as they come available -- several of the benefits come
from both the filters and some very clever exhasut and catalyst
systems that will gradually become available.  Interestingly, though,
with the right technology, a lightweight diesel could easily surpass
the fuel use of current hybrids, with relatively similar emissions.
Hybrids are heavy, due to their batteries, and by putting smaller
engines in very lightweight cars, diesels could be a good alternative.
(That won't happen, of course, because the trend in automaking is for
heavier cars.  People want giant pillows and huge piles of steel around
themselves, in case of collision.  All thoughts of road design, driver
training, and handling are secondary to this naive conception of
"safety".  But that's a rant for another day.)

For lots of interesting stuff about diesels in general, I suggest
http://www.dieselnet.com/.  It's an industry forum, note, so you don't
get all the criticism that is perhaps justified.

Best regards,
Andrew Sullivan
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