Hybrid Car – More Fun with Less Gas

Vehicle Gas Consumption - Accurate? - Page 13

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Posted by News on May 22, 2012, 6:24 pm
On 5/22/2012 11:22 AM, Bruce Richmond wrote:

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To the point, do you see any indication of the OP's observation --
consistent calculated MPG error and directional bias?

Posted by Bruce Richmond on May 22, 2012, 7:19 pm

I see that a measurement is being made and that every measurement can
include a calibration error.  If the flow rate of the injector is off
it is extremely unlikely that it would change size back and forth to
any great extent.  While the error could go either way it is likely
that Toyota would prefer to see higher mpg displayed, so if there must
be an error they bias it in that direction and overall you end up with
a consistantly high bias in that direction.  From what I have
experienced the bias is small enough that it is less significant than
the error introduced by the shut-off point used to determine when the
tank is "full" and the 'at the pump' calculation is made, particularly
when dealing with a variable like the air bladder used in the early

Posted by Green Eggs & No Spam on October 2, 2012, 2:29 pm
 On 5/22/2012 12:19 PM, Bruce Richmond wrote:


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Loath as I am to get involved in newsgroup pissing contests, this seems
to be verging into the "How many angels can dance on the head of a pin?"

There are many variables in gasoline consumption, including but not
limited to how one drives, the weather conditions, traffic flow, whether
you fill up (sic) at 2 PM in the summer or 7 AM in the winter, the
gasoline blend (E10 is becoming more common year-round in some states,
and in winter months in others), the type and size of the tires on the
vehicles, etc. I suspect most folks drive their cars to get from here to
there, not for a chemistry lesson.

I have two hybrids, and while I find the on-board MPG calculations
interesting, I also keep spreadsheets that calculate MPG and $PG based
on the data given which is not precise but is good enough for what I
want to know, i.e., "How am I doing? Is there something needing
attention with my car or with my driving? Are my tires properly
inflated, needing rotation or re-balancing or replacement? Is it time to
replace the fuel filter? How soon do I need to refuel (that one usually
is off to the sooner than later side). Wow now matter which way you
drive I-80 across Wyoming, the wind rarely is right behind you."

Even if I knew the chemistry of the fuel - for each and every fill-up,
what practical difference would it make to me? I'm not designing an
engine or working for a refinery. I'm driving a car. I suspect that most
folks in the real world care more about the immediate practical factors
than the theoretical, of which even the fuel chemistry is only one

Posted by Elmo P. Shagnasty on May 19, 2012, 9:16 pm
 In article

He'll tell us that after he tells us which weighs more, a pound of
feathers or a pound of lead.

Posted by News on May 19, 2012, 9:25 pm
 On 5/19/2012 5:16 PM, Elmo P. Shagnasty wrote:

How about a pound of your bullshit posts.  Really weighty stuff.

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