Posted by Michael Pardee on August 17, 2006, 2:03 am
> ...but surely, surely, you see that all that energy came from the gasoline
> engine in the first place, which was my point? Sure, in a conventional
> car
> slowing / braking energy is wasted, but even with a Prius there is no free
> lunch.
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
Posted by =?iso-8859-1?Q?mark=5Fdigital= on August 17, 2006, 8:41 am
>>
>> ...but surely, surely, you see that all that energy came from the
>> gasoline
>> engine in the first place, which was my point? Sure, in a conventional
>> car
>> slowing / braking energy is wasted, but even with a Prius there is no
>> free
>> lunch.
>>
> 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.
Posted by Bill on August 17, 2006, 2:46 pm
> 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? :-)
Posted by mrv@kluge.net on August 17, 2006, 4:58 pm
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:
> Look, all I'm
> trying to find out (as per my first post) is what mileage drivers such as
> you actually get per (US) gallon you put in the tank, as opposed to what
> Toyota's dash gauge (whether or not we agree it's a trip computer) tells
> you.
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
> I'd be
> interested in a car that was truly as economical as claimed but not if (in
> fact) it's easy to get the same economy with a much cheaper diesel engine.
> I'm just trying to make a fair comparison, is all.
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
Posted by Bill on August 17, 2006, 5:40 pm
Sorry to top-post but I just wanted to compliment you on your excellent,
comprehensive reply to Steve's question. Scroll no further.
>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:
>> Look, all I'm
>> trying to find out (as per my first post) is what mileage drivers such as
>> you actually get per (US) gallon you put in the tank, as opposed to what
>> Toyota's dash gauge (whether or not we agree it's a trip computer) tells
>> you.
> 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
>> I'd be
>> interested in a car that was truly as economical as claimed but not if
>> (in
>> fact) it's easy to get the same economy with a much cheaper diesel
>> engine.
>> I'm just trying to make a fair comparison, is all.
> 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
>
> engine in the first place, which was my point? Sure, in a conventional
> car
> slowing / braking energy is wasted, but even with a Prius there is no free
> lunch.