Question about MPG - Page 6

 


That is true, but gasoline isn't used at constant efficiency. Idling is 0%
efficient and moving slowly is scarcely any better... worse as the engine
displacement increases. Hybridization allows the very low efficiency modes
to be replaced by electricity generated when the engine is developing power
and getting much better efficiency. In combination with allowing downsizing
of the engine (the electric side determines the acceleration) that accounts
for the tremendous increase in in-town efficiency and modest increase in
open road efficiency of hybrids.

Mike

 



In the old days the slightest downward movement of the gas peddle caused the
fuel injector to squirt extra raw fuel. I remember experimenting with
disconnecting it. There would be a momentary bog down as I tried to rev the
engine. With the hybrid the fuel accelerator is replaced by a momentary
boost from the electric motor.  Another fuel savings is from the lack of a
mechanical linkage between accelerator peddle and engine.

The electric motor provides for an extended coasting (to a red light for
example) that if it weren't for the motor the car would come to a halt very
short of reaching the light. With a traditional power train anticipating  a
red light up ahead by letting up on the gas peddle saves almost nothing.
Actually, it rather comical to watch people zoom right up to a light when
they knew it was red maybe 500 feet back or more.

Hybrids aren't for everyone. I dare say they are more suited for those of us
who need not show our emotions by the way we drive. You can't rev the
engine. You can't pass another car and make a lot of noise. These things
don't cut it in the Animal Kingdom where growling and snarling cars helps
people let off steam. So I guess if I have something to say, I step out of
the car. Amazing how the other driver's safe heaven now becomes their prison
while I lean on their hood and ask, " Do you have a problem?" Last time I
did that (guy was flashing his high beams on a 35 mph road) he nearly
crapped his pants. He denied flashing his lights.

 



Couldn't this be fixed with gas pedal controlled sound effects
switch-selectable between, say, Hog, Mac, & Titanic?  :-)

 

I apologize if my message is a little curt...  IE just went and ate my
longer and much thought out response.  (GRR!)  Hopefully I get it all
right this second time around.

Steve Pardoe wrote:


http://autos.groups.yahoo.com/group/toyota-prius/surveys?idD4783
Question
On average, what is the difference between your mpg calculated by the
car's computer and by the gas station fill-up method?
499 responses:
Choices  Votes  %
computer 5mpg or more higher  17  3
computer 4mpg higher  38  7
computer 3mpg higher  70  14
computer 2mpg higher  107  21
computer 1mpg higher  12  2
both methods about the same  128  25
computer 1mpg lower  5  1
computer 2mpg lower  9  1
computer 3mpg lower  15  3
computer 4mpg lower  4  0
computer 5mpg or more lower  6  1
varies too much to give meaningful average  88  17



The only fair comparison is between similar-sized vehicles, using a
standardized test, such as offered by various governments.

And it's not what is "claimed" - the manufacturers are required by law
to post the fuel economy results of the governmental tests and no other
figures.

post from Toyota GB press relations:
http://autos.groups.yahoo.com/group/Prius-UK/message/7619

Prius Fuel Economy: Explaining the EPA Ratings
Toyota  explains what the EPA ratings actually mean, and lists ways to
improve your MPG
http://autos.groups.yahoo.com/group/toyota-prius/message/71431
http://autos.groups.yahoo.com/group/Prius-2G/message/2742
http://www.priusonline.com/viewtopic.php?t 79

Prius Fuel Economy Factsheet:
http://www.toyota.com/images/vehicles/prius/Understanding_Fuel_Economy.pdf


For comparisons:
US: http://www.fueleconomy.gov/
Canada: http://oee.nrcan.gc.ca/transportation/personal/
UK: http://www.vcacarfueldata.org.uk/

US 2006 best mid-sized cars:
http://www.fueleconomy.gov/feg/best/bestworstNF.shtml
1: Toyota Prius (Hybrid), 4 cyl, 1.5 L, Automatic(Variable), Regular
gasoline, 60 US MPG city, 51 US MPG highway
2: Hyundai Elantra, 4 cyl, 2 L, Manual(5), Regular gasoline, 27 US MPG
city, 34 US MPG highway

Canada 2006 best mid-sized cars:
http://oee.nrcan.gc.ca/transportation/tools/compare/compare-search-one.cfm?attr=8
1: TOYOTA PRIUS (HYBRID), regular gasoline, 4.0 l/100km (71 imp MPG)
city, 4.2 l/100km (67 imp MPG) highway
2: MERCEDES-BENZ E320 CDI TURBO, diesel, 8.9 l/100km (32 imp MPG) city,
5.9 l/100km (48 imp MPG) highway

Unfortunately, the UK site doesn't break out the size classes, but they
will sort by fuel economy.  The Prius is in the highest band of cars,
in the 60-70 imp MPG range or 1-5 l/100km range, along with a bunch of
tiny diesels.
http://www.vcacarfueldata.org.uk/search/fuelConSearch.asp

 

Sorry to top-post but I just wanted to compliment you on your excellent,
comprehensive reply to Steve's question.  Scroll no further.


http://oee.nrcan.gc.ca/transportation/tools/compare/compare-search-one.cfm?attr=8