Fuel economy myths

This is true, we do have an average mpg of around ~35 these days, but
thats not the point really - my point was that even at 770 a gallon it
makes no odds to peoples usage. Everyone moans, everyone complains about
the taxes (its something close to 80% tax in total IIRC) but people
dont change their habits. Sure there are some that get a smaller car,
but most just carry on as before with each increase. Increasing fuel
costs wont bother anyone until it exceeds public transport costs by a
LONG way. Here in the UK I can get a (late,smelly,crowded) train to my
place of work for ~£6 return. Or pay £7 and drive in comfort in a very
low mileage car. You'd have to either make fuel ~$15 a gallon or reduce
the cost of the trains significantly to make any of the majority
reconsider car use.

 

snip

Lower speed limits don't always translate in lower fatality rate, as these
sites seem to indicate.

http://www.hwysafety.com/hwy_montana_2001.htm
http://www.stateline.org/live/ViewPage.action?siteNodeId=136&languageId=1&contentId=13621
http://www.motorists.org/pressreleases/home/montana-no-speed-limit-safety-paradox/

 

It will depend on the car.
Many things come into the equation. Coefficient od aerodynamic drag
will be one of the primary ones. A vehicle with a CD of .27 will be
significantly more efficient, and see a slower decay in efficiency
with speed, than one with a CD of .5.

The second major contributor will be the power/torque curve of the
engine. An engine produces the most HP minutes per lb of fuel when
running at it's maximum torque RPM. If the torque curve is nice and
fat (not peaky) and the gear ratios are correct, the car can run with
the engine in it's sweet spot over a wider range of speeds, and the
overlap of the engine efficiency sweetspot and the aerodynamic
sweetspot can make the vehicle actually MORE efficient slightly above
the aerodynamic sweet spot than at it. Obviously, the POTENTIAL for
better mileage exists - but not with that particular combination.

Secondary to the primary considerations are weight issues and the
related inertia. The lighter the car the better. The lower the
rotational inertia of the driveline the better. The lower the friction
in the driveline the better. The lower the rolling resistance of the
tires, the better. The less brake drag the better.
Most of the secondary issues are less speed sensitive tan the 2
primary issues, and of coarse, the "weight of the right foot" has to
be factored in as well!!!

 

How do you figure we have a mileage of 35mpg???

I think fuel mileage isn't getting any better than it was 30 years ago.

 

No, not at all. If people are not given an ultra-convenient refueling
mechanism they will very quickly adapt. You need to think outside of
the box here. The problem with fueling passenger cars in the future once
sources of gasoline run out isn't going to be solved with thinking
inside of the box.

In all liklihood since we have a lot of coal reserves, once oil gets
too expensive someone will come up with some horrendously
energy-expensive method of converting coal into some kind of
liquid fuel - be it gasoline or some other flammable liquid or
flammable pressurized gas. That will probably stave off the
inevitable for another 50 years. But ultimately your going to
see most vehicles running on electricity. Economically, it
makes no sense to obtain electricity from wind or solar then
convert it into yet another form of energy, like pressurized
hydrogen or some such, and burn that in a fuel cell to produce
electricity again to power electric motors when you can just
charge batteries with it. So pricing on liquid-fueled vehicles
will always be higher than just running them off the power
grid. That price won't be paid unless the vehicle is a truck
or something that requires so much energy that battery power
wouldn't work.

Ted

 

Check the average vehicle consumer's pulse. He/she doesn't think
outside the box, and changing that mentality that's been ingrained for
almost a hundred years will not happen easily.

We probably have enough fossil fuel to continue making status quo
vehicles for another 50 years.

This is all assuming that the cost to produce said vehicles has come
down to roughly the same cost as fossil-fueled vehicles. Most
automotive consumers have a valid concern over the TCO.

I believe ultimately it will all come down to a balance between
economics and convenience. The average automotive consumer will most
likely be shopping on a budget, but with the added factor of convenience
in mind. People are doing that now - while living paycheck to paycheck,
some will still purchase dinner 4 or 5 nights a week (as opposed to
making it at home) because it allows them more time for their other
activities, albeit at a price. I don't believe automotive consumers are
any different. They simply won't give up features they've gotten used
to, like refueling in a matter of minutes.

 

Going from a friend-questioning at the pub, most people and their family
report between 30 and 40mpg, the odd one gets 45 regularly, the odd one
(me) gets 20-24. Entirely un-scientific but based on the real-world
experience of 20+ people across a range of cars and operating conditions.

 

Two questions you never believe the answers to:

What gas mileage do you get.

How often do you have sex.

 

Splendid. If you were in the original Durham you would be paying maybe 92+
pence per litre, more than double...

:-(
DAS

 

Miles per imperial gallon, presumably.

I am also in the UK. I get 26 mpg in my 3.2 l motor. It's an older car now
(2001) with 6
cylinders. As I do less than 5000 miles pa I don't care too much about
prices. Biggest cost anyway is depreciation, followed by insurance.

DAS

 

Pretty sure none of my friends have any need to lie about their fuel
mileage, certainly in the 7 cars in my close family we average ~30ish,
held up by my brother in his 330d and my missus in her 1.6 renault. That
said, some of my mates are so car-unfriendly I'd be less than convinced
by their calculations, but by rough "i get Xmiles per tank" quotes they
seem right enough. I really cant understand why anyone would WANT to lie
about MPG - unlike the second point lol.

 

It certainly has improved for the larger cars and engines.
I do agree that for smaller cars and engines there has been little
improvement in fuel mileage, but small engine power has increased
significantly.

 

So what you're saying is we're really going the wrong way?

Honda Civic...

1985 34mpg
1995 38mpg
1999 30mpg
2007 29mpg
(fueleconomy.gov)

Why would we want to decrease fuel economy, for a only slightly better
working car?

Thats probably only one car though, i don't have time to do others

I would guess pickups have hovered somewhat the same... maybe only
slighly better with smaller efi engines doing the same job and making
more power.

 

I prefer using L/100KM, keeping in canadian style, but nobody knows what
the hell you're talking about.

7.8L/100KM = 30mpg

my ranger 3.0L gets 13l/100km ... 16.8mpg

I'm talking US MPG

1L/100km = ~235 (i use that for rough math in the truck)

 

clare at snyder.on.ca wrote:

Two questions you never believe the answers to:
1.) What gas mileage do you get?
2.) How often do you have sex?
___________________________________________

"Coyoteboy" wrote:

Some of my mates are so car-unfriendly I'd be less than convinced
by their calculations, but by their rough "X miles per tank" quotes
they seem right enough. I cant understand why anyone would
WANT to lie about MPG.
_____________________________________________

I once had a motorhome that got about 7-8 mpg. Whenever I fueled
up someone nearby with a small car would invariably ask, "What kind
of mileage does that thing get?" To avoid the somber headshaking
and eye-rolling I would say, "I get 19 miles per gallon, but only if I go
easy on the gas going uphill!" It was delightful to see their facial
expressions as their brains tried to cope with the unexpected answer.

Rodan. < - - - - Showing an uncharacteristic mean streak.

 

But is this really the same car? The name may still be the same, but the
Civic today is closer in size to the Accord of some years ago. We keep
asking for (and getting) larger cars. I'm not sure how many cars you can
directly compare having the same name and being interior size over a 15 year
span. Crown Vic? LeSabre?

 

We're making choices that result in lower fuel mileage.

Yet there is the new Honda Fit, which is smaller than the Civic and gets
better mileage. And the Civic hybrid, Prius, etc.

Larger cars and more power.

It's a common trend. You start with a small car. Over time, successive
generations tend to get bigger, more powerful and less fuel efficient.

I think pickup trucks have gotton larger over time, with more power, too.

Jeff

 

I'd just call you a liar and walk off

 

The 2007 Civic is the size of a 1999 Accord.

 

I'm basing my comments on the history of my own total fuel mileage of
similar driving with:
-1948 Austin A40
-1949 Pontiac 6 cyl flat head.
-1956 VW 1.1L
-1961 VW 1.3L 1,600 lb.
-1963 Chev II 6cyl
-1970 Datsun 1.6L 510 1,900 lb.
-1986 Chrysler 2.5L LeBaron
-1995 Chrysler 3.3L Concorde
-2001 Chrysler 2.7L V6 Sebring

The improvement in mileage of my last 3 cars over the 1949 Pontiac,
which was in first class running condition, is just amazing. The
Pontiac was typical of that ERA. Over a 50% improvement on the highway
and 60 to 90% improvement in city driving. The biggest city
improvement is in winter time. The 1963 Chev II was in the middle of
the my larger cars for mileage.
The last three mid sized cars give similar mileage to the older small
engined ones, but much more consistent on the highway in the winter. The
Concorde is still the best I've had on the highway, yes better than the
Sebring at 110kmph/70mph.
I keep track of all my fuel used and mileage. That sure is easier now
that I carry a Palm.