Hybrid Car – More Fun with Less Gas

40 mpg Prius vs 50 mpg European Diesel cars - Page 30

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Posted by Ken on May 12, 2006, 4:19 am

<And you neglect the fact that in conventional (non-hybrid)
installations, diesel engines need all the stuff a Prius doesn't:
alternator, power steering pump, belts and followers, clutch or torque
converter, transmission, shifter and linkage, and so on-- all of which
needs maintenance, the occasional repair, and periodic replacement of
significant components.  By comparison, the hybrids need their little
planetary-gear power-split gizmo, two electric motors, and a battery. >

Well it still finishes up pretty much a line ball for diesel - higher
production costs offset either by greater volume or longer life.

The unanswered question is, assuming we are talking about a form of
diesel which is no more or less polluting than petrol, what is the
relative cost of the fuel - not the cost at the pump but the cost of
production? A relevant factor is whether you can get more or less
diesel (compared with petrol) from the crude. Refining is a black art
and most of the cost differentials around the world as between petrol
and diesel are artifacts of government policies (or that is my
impression anyway).

Posted by Ken on May 12, 2006, 4:33 am

The following link sheds considerable light on relative cost of
production of petrol and diesel. The striking thing is that, for an
given type of crude (and, I suppose, any given refinery) there is an
optimum ratio of the volume of output between the two fuels. Changing
this affects costs directly and, also, indirectly by increasing
pollutant problems which have to be addressed at increased cost.


Posted by Geoff Miller on May 12, 2006, 12:50 pm

Is it really an either/or proposition?  I always had the impression
that petrol and diesel fuel came from different fractions in the
catalytic cracking process.  Is that not the case?


"If I underfed a janitor, would he cling sucker-mouthed to the
 surfaces of my cube, slurping up paper algae?" -- C J Silverio

Posted by Bruce L. Bergman on May 12, 2006, 3:00 pm

On 12 May 2006 05:50:56 -0700, geoffm@u1.netgate.net (Geoff Miller)

  You win this point - that is the case if you talk about the natural
raw products in the simple stages of refining.

  Now if they want to spend a bunch of energy cracking the heavier
hydrocarbons that would make diesel into lighter ones for gasoline, or
the opposite by combining the light ones to get more diesel out of
that barrel of crude, they can.  But while it adjusts their output, it
also adds a bit of cost.

      --<< Bruce >>--

Posted by mrv@kluge.net on May 9, 2006, 2:44 pm

Ray O wrote:

Could be because the diesel engine is in fact dirtier than the gasoline
models you mention?  For example, you cannot buy a new VW TDI diesel in
my state, because the emissions are so bad.

2006 VW Golf TDI, EPA air pollution score of 1, LEV.  Not sold in CA or
the New England states.

2006 VW New Beetle TDI, EPA air pollution score of 1, BIN9.  Not sold
in CA or the New England states.

2006 Toyota Highlander Hybrid, EPA air pollution score of 8, BIN3, not
sold in CA or the New England states, or for the CA emission version is
an air pollution score of 9, SULEV II.

2006 Toyota Highlander Hybrid, EPA air pollution score of 8, BIN3, not
sold in CA or the New England states, or for the CA emission version is
an air pollution score of 9.5, SULEV II.

(fueleconomy.gov doesn't have the 2007 model years available yet,
otherwise I would've included the available 2007 Toyota Camry hybrid.
no score was listed for the VW Jetta TDI.)

(EPA air pollution scores are based on 1=worst, 10=best.  For the
Maximum allowed grams per mile Emission limits at full useful life
(100,000-120,000 miles), see:
http://www.epa.gov/greenvehicles/rating.htm  )

To note the limits for the non-CA emission states (listed as maximum
grams per mile):

NOx=Oxides of Nitrogen: Compounds containing nitrogen and oxygen; they
combine with hydrocarbons in the sunlight to form smog
1 = 0.6
8 = 0.03

NMOG=Non-Methane Organic Compounds: Compounds containing carbon; they
combine with NOx in the sunlight to form smog
1 = 0.280
8 = 0.055

CO=Carbon Monoxide: A colorless, odorless, poisonous gas
1 = 6.4
8 = 2.1

PM=Particulate Matter: Tiny particles of solid matter that lodge in the
lungs and deposit on buildings
1 = 0.08
8 = 0.01

HCHO=Formaldehyde: A lung irritant and carcinogen
1 = 0.027
8 = 0.011

So yes, I would say that the diesels are dirtier (more than 2x for
HCHO, 20x for NOx) than the Toyota hybrids, because they are.

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