In response to your question on cabin heating, the EPA fuel tests are 
dynomometer based and NO accessories are on.  There is no radio, no compressor 
if hot, no fan, no wipers, no headlights, no defrosters, etc.  Even for the 
diesel, because the fan in the climate system is off, there is probably 
insufficient heat.  When these accessories are on, they will affect fuel 
economy 
in gasoline, diesel, and electric powered vehicles, probably somewhat 
differently.  The sense of these rules can certainly be questioned, but they 
are 
the rules.

Actually, some diesels have insufficient waste heat for cabin heating and need 
supplemental electric heating; obviously that is a big hit on fuel economy.  A 
few have used supplemental diesel heaters (small fuel-oil furnances).




________________________________
From: Stanislav Jakuba <[email protected]>
To: U.S. Metric Association <[email protected]>
Sent: Tue, December 7, 2010 8:25:48 PM
Subject: [USMA:49050] electric car


Attached is a follow-up info about the diesel vs. electric car. The respective 
consumption numbers are in the units of both: distance-per-energy (ala mpg) and 
energy-per-distance (ala L/km). 

Aside from showing the units, I should like to point out that the 50 mpg for 
the 
VW is exceptionally good. But also the EPA estimate for the Leaf is probably 
optimistic, and I wonder how much consumption was accounted for the cabin 
heating, if any. A point of interest: a 32 mpg diesel would equal the 34 L/100 
km Leaf in the table. 


A newspaper quoted a $120,000 Tesla buyer reasoning for his purchase by this 
energy analysis: "I can go from 0 to 60 on a penny's worth of energy vs. a 
buck's worth of energy [with a Porsche or similar]." The attached table helps 
to 
see the fallacy. And the comparison comes out worse yet when one realizes that 
"990 lb of the 2700 lb car is in the batteries." The Excel attachment shows an 
SAE survey of mass vs. consumption increase.

That wealthy buyer's statement indicates how ignorant the general public is 
about energy issues. Among the reasons for the ignorance? The mess of non-SI 
units in use. And the lack of education that is partially due to the mess.
Stan Jakuba

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