[SGVLUG] [OT] Especially for Tom & his Prius.... [my rebuttal, then I'll shut up]

[Dustin Laurence]

On Tue, Jul 11, 2006 at 12:53:09AM -0700, Michael Proctor-Smith wrote:

> Speaking of CARB apparently they are changing the diesel regulations
> for 07 or 08 and some of the cool new TDI will no longer be available
> in California :-(

It's complicated. :-)

My understanding is that <takes deep breath>: for a long time now it's
been illegal to sell a light diesel in CA with < 7500 miles, because of
point emissions.  In September in CA all diesel must be ultra-low
sulphur, so in the 2007 model year it will be legal to sell light
diesels again, including the TDI's.  But the next year the emissions
standards will be tightened, and VW's current Pumpe Duse TDI's can't
meet the tightened regs, so they'll withdraw again from the CARB state
market for 2008--mostly.  Mercedes won't--their common-rail engines will
meet the regs.  But the regs are based on the dates the cars were
produced, so VW is going to stockpile some made before the deadline.  So
there might be some available for a few months in 2008 anyway.  VW then
expects to have a common-rail design ready and re-enter the market in
the 2009 model year.

You'd think it would be done there, but no--the regs keep tightening
over several years, so whether Mercedes and VW can continue to meet the
regs is an open question.  I expect so, but apparently it's not a gimme.

> I know you must be joking as modern cars simply do not make it to
> production without wind tunnel time and things like checking it they
> produce lift.

Wind tunnel testing isn't often good enough:

http://www.mulsannescorner.com/benzCLR1.html
http://www.mulsannescorner.com/techarticle1.htm

But yes in general I was joking.  For Tom's specific car it actually
wouldn't surprise me if it produces lift though (it certainly is shaped
suspiciously like an airfoil): it doesn't go fast enough to generate all
that much lift (I seem to recall that ground effects only start to kick
in >~ 100 mph).  I'm not convinced that Toyota went to a lot of trouble
to avoid lift in a region the car can't achieve, and they were motivated
to optimize for low drag instead of worrying about lift at, say, 150+
mph.  I'd not want to drive a souped-up new beetle at 200mph either,
though I think VW would have cared about high speeds for the new beetle
more than Toyota did for the Prius (they have faster versions and there
is far more liklihood of it being souped up).

> ...But I agree the road to Vegas is for checking how fast
> your car will go.

It's the fastest freeway in the country AFAIK; we drive slower in
Montana with no speed limits (besides, over 80 in Montana is actually an
automatic careless driving ticket).

> Well just wait if any one really gets serious about mpg you will have
> TDI electric hybrids.

I hope so, because it makes more sense than a gas hybrid.  Toyota choose
an Atkinson engine, which was a good idea, but not as good as diesel.
The main reason we don't have one is that VW doesn't like the
technology.  Well, that and the fact that CA is probably the best market
in the world for hybrids and they were forbidden from selling light
diesels here.

IIRC Honda has said that they're going to develop a diesel for the US
market and they have certainly chosen a corporate strategy to be "the
greenest car company in the world," so I would not be surprised if Honda
beats VW to the punch.  Toyota probably won't because they seem to be
avoiding diesels, at least here.  If so, it's purely VW's fault--they
have a rotten marketing department and don't seem to understand the US
market, while Honda really does.

I still think in the long run a turbine can be made more suitable for a
hybrid than a diesel, but not in a timeframe that would make you not
want to develop the diesel (probably the same timeframe that might make
fuel cells not entirely fantasy).  And advanced diesel hybrid is
probably the most efficient city vehicle we actually know how to build.
The turbine option would probably have to be a combined-cycle engine,
and that would take some real development for a road car.

Or so Dustin says about a very complex subject off the top of his head.

> maybe the electric motor is not that much of a help with a TDI as
> torque is not going to be a problem even with a small displacement
> TDI.

I think it's not that different from the gas version, really.  It isn't
going to help much for freeway cruising, it actually hurts--since the
engine ultimately has to produce all the power, it's a waste to drag the
weight along.  That is compensated for somewhat by the fact that you can
make the engine a bit smaller and use electric power for passing.

The big win, as always with a hybrid, would be city driving.  I think it
still helps--sure, the diesel needs less help at low RPMs, but diesels
don't like to be run up and down through a wide RPM range, and electric
motors are great for that.  The electric still provides extra power off
the mark and recaptures some energy while braking.

Another way it would help is that the car could hopefully drive for the
first five minutes or so on pure electric while the diesel warms up
gently, like diesels want--diesels *hate* running cold.  Most people
don't live closer than that to a freeway anyway.

I suspect that for city driving diesel hybrids should win, while for
freeway driving straight diesel should win.  If there were a choice,
people could buy their vehicle based on their usual driving patterns.  I
may be wrong, since the TDIs do impressively well in city driving too,
but I think the Prius' performance suggests I'm right.

To be honest a natural gas hybrid would be a killer in terms of
emissions, but I don't think anybody is going to be able to cram those
big tanks and a hybrid drive into a passenger car.  Plus, natural gas is
still a fossil fuel and is likely to remain so.

> One of the guys at my work wants his then car to be bio-diesel. Maybe
> Americans will wake up and smell the french fry smelling exhaust.

I heard someone working at a biodiesel station saying that when there
were a lot of customers the smell made her hungry. :-)

Dustin

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
Url : http://www.sgvlug.net/pipermail/sgvlug/attachments/20060711/612ccf95/attachment.bin