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max possible gas mileage

E

Eric

Jan 1, 1970
0
I was wondering what the theoretical limit was on gas mileage
Someone somewhere must have figured that out that.

The ingredients would be something like:
1. some kind of standardized vehicle shape and weight
2. a specified driving profile (ie speed) over a fixed course
3. a specific gasoline formulation (unleaded 89 octane)
4. determine the amount of energy in a gallon of the above fuel
and compute energy required to complete the course, thus
giving you computed mpg at absolutely 100% efficiency

The results might be quite enlightening, especially when the same
calculations are done for a variety of fuels (ie diesel, hydrogen etc),
graphing against speed, car body shape, weight etc
It might also debunk a lot of those wacky claims by hucksters trying to
sell you various pills/additives/carburettors etc to get "better mileage"
AND, here's a nifty benefit, it would help people to compare various fuels
so you could make a somewhat better informed decision about alternatives.
Thanks,
Eric
 
R

rebel

Jan 1, 1970
0
Eric said:
I was wondering what the theoretical limit was on gas mileage
Someone somewhere must have figured that out that.

The ingredients would be something like:
1. some kind of standardized vehicle shape and weight
2. a specified driving profile (ie speed) over a fixed course
3. a specific gasoline formulation (unleaded 89 octane)
4. determine the amount of energy in a gallon of the above fuel
and compute energy required to complete the course, thus
giving you computed mpg at absolutely 100% efficiency

The results might be quite enlightening, especially when the same
calculations are done for a variety of fuels (ie diesel, hydrogen etc),
graphing against speed, car body shape, weight etc
It might also debunk a lot of those wacky claims by hucksters trying to
sell you various pills/additives/carburettors etc to get "better mileage"
AND, here's a nifty benefit, it would help people to compare various fuels
so you could make a somewhat better informed decision about alternatives.
Thanks,
Eric

////////////////////////
I have a French vehicle an Axiam it is a bit crap and expensive for what it
is it's saving fact is it returns 80 mile per gallon. good for rural work
steady plodder.
 
E

Eric

Jan 1, 1970
0
rebel said:
I have a French vehicle an Axiam it is a bit crap and expensive for what
it is it's saving fact is it returns 80 mile per gallon. good for rural
work steady plodder.
Thing is, its probably the size of a tuna can and about as comfortable.
for me, I refuse to run my house at 55F or ride around crammed into a rattle
trap, take cold showers, or live in the dark. Thats not life. Of course
others are free to do just that - more power to em.
I am most willing however to conserve in reasonable ways. I use a couple of
compact flourescents in the kitchen that are on nearly continuosly. I dont
want a 12mpg truck or car and wont buy one. I'll spend the extra money
when, the numbers work, to get a highly efficient water heater, furnace or
AC system. If i build a house i'll install extra insulation, buy the better
windows and doors etc.
Long ago i lived like a friggin refugee in a damn cold cottage with no heat
to speak of, i remember getting up in the morning to go to work and having
frost on the floors. I swore that I would never live like that again. I
also promised my wife when we got married that our family would always live
life in reasonable comfort, have decent food, warm water etc etc. no
matter what it took.
But, that doesnt address my original post. A lot of people make wild claims
about gas mileage, like you. 80 mpg? US gallon? If its anormal small car
then Id have to say:
Its like my granny used to say: "Maybe so sonny! But I kinda fuckin doubt
it"
Eric
 
M

mike wilcox

Jan 1, 1970
0
Eric said:
rebel wrote:



Thing is, its probably the size of a tuna can and about as comfortable.
for me, I refuse to run my house at 55F or ride around crammed into a rattle
trap, take cold showers, or live in the dark. Thats not life. Of course
others are free to do just that - more power to em.
I am most willing however to conserve in reasonable ways. I use a couple of
compact flourescents in the kitchen that are on nearly continuosly. I dont
want a 12mpg truck or car and wont buy one. I'll spend the extra money
when, the numbers work, to get a highly efficient water heater, furnace or
AC system. If i build a house i'll install extra insulation, buy the better
windows and doors etc.
Long ago i lived like a friggin refugee in a damn cold cottage with no heat
to speak of, i remember getting up in the morning to go to work and having
frost on the floors. I swore that I would never live like that again. I
also promised my wife when we got married that our family would always live
life in reasonable comfort, have decent food, warm water etc etc. no
matter what it took.
But, that doesnt address my original post. A lot of people make wild claims
about gas mileage, like you. 80 mpg? US gallon? If its anormal small car
then Id have to say:
Its like my granny used to say: "Maybe so sonny! But I kinda fuckin doubt
it"
Eric

The Volks Lupo get's close to 100mpg, it's the size of the golf.
 
H

Harry Chickpea

Jan 1, 1970
0
Eric said:
I was wondering what the theoretical limit was on gas mileage
Someone somewhere must have figured that out that.

The ingredients would be something like:
1. some kind of standardized vehicle shape and weight
2. a specified driving profile (ie speed) over a fixed course
3. a specific gasoline formulation (unleaded 89 octane)
4. determine the amount of energy in a gallon of the above fuel
and compute energy required to complete the course, thus
giving you computed mpg at absolutely 100% efficiency

The results might be quite enlightening, especially when the same
calculations are done for a variety of fuels (ie diesel, hydrogen etc),
graphing against speed, car body shape, weight etc
It might also debunk a lot of those wacky claims by hucksters trying to
sell you various pills/additives/carburettors etc to get "better mileage"
AND, here's a nifty benefit, it would help people to compare various fuels
so you could make a somewhat better informed decision about alternatives.
Thanks,
Eric

Do a web search and you'll eventually come across the "racers" that go
for this. IIRC, 600 to 800 mpg is the norm, but it probably is much
higher now. Ultralightweight, super-hard tires, tiny engine, slow
speeds and a lot of coasting. No provision for even much venting,
much less air conditioning.
 
P

Pooh Bear

Jan 1, 1970
0
mike said:
The Volks Lupo get's close to 100mpg, it's the size of the golf.

The Lipos's significantly smaller than the Golf. You're talking UK mpg and it
doesn't get 100 either ! More like 70 perhaps in the real world.

Graham
 
D

danny burstein

Jan 1, 1970
0
In said:
Rolling friction and drag is what uses the gas. Sports cars have drag
coefficients like .25. Trucks are like .9. The formula for drag is
.5*rho*V^2*S*Cd. rho is air density... 1.2 kg/m^3 about. S is the
frontal area in m^2. It takes about 15Hp to push thru the air at 40mph,
but it starts going up fast. A 100mpg car would have to be real light
(small rolling friction) and real slippery. Like maybe 1500lbs, 20HP,
and cruising at 45 or 50. And hi pressure tires.

The Honda Insight - gasoline powered, hybrid - has a bunch
of crazed owners.... The _regular_ and real mpg on the
manual is typicaaly 70 or so highway. (My personal range
is normally about 55-60 on the highway with auto transmission).

Every so ofen one of the " hyper-milers " reports doing over 100 mpg.

(I've gotten as high as 75.4 on a 50 or so mile stretch. There
was a steady 30 + mile wind helping...)
 
W

WKSmith

Jan 1, 1970
0
Eric said:
I was wondering what the theoretical limit was on gas mileage
Someone somewhere must have figured that out that.

The ingredients would be something like:
1. some kind of standardized vehicle shape and weight
2. a specified driving profile (ie speed) over a fixed course
3. a specific gasoline formulation (unleaded 89 octane)
4. determine the amount of energy in a gallon of the above fuel
and compute energy required to complete the course, thus
giving you computed mpg at absolutely 100% efficiency

The results might be quite enlightening, especially when the same
calculations are done for a variety of fuels (ie diesel, hydrogen etc),
graphing against speed, car body shape, weight etc
It might also debunk a lot of those wacky claims by hucksters trying to
sell you various pills/additives/carburettors etc to get "better mileage"
AND, here's a nifty benefit, it would help people to compare various fuels
so you could make a somewhat better informed decision about alternatives.
Thanks,
Eric

It's a fool's game to set a theoretical maximum. Someone is always
disproving it. I remember when there was a competition to design a vehicle
to get the most mileage on a closed track. It was a needle-shaped affair
with a reclining pilot, who kept applying little spurts of power in short
intervals. I think it was some advanced brain who declared that the
theoretical maximum of such a vehicle was about 800 MPG. It wasn't very
long after that before someone had surpassed 1600 MPG.

I found this link for you, but you can google as well as I.
http://www.guinnessworldrecords.com/content_pages/record.asp?recordid=43581
 
P

Pooh Bear

Jan 1, 1970
0
but this is not amenable to standardisation in the real world. Ongoing
improvement in aerodynamics and changing expectations are the reality.
Shape and weight have alot to do with safety too, another ever changing
element.


depends entirely on the amount of change of speed. I suppose you coudl
factor in 100% efficient regenerative braking, but thats pretty
optimistic and would IRL work counter to your goal due to ading
unnecessary weight that >95% of the time does absolutely nothing.


Mother of God... > 11,000 mpg!

I suppose the best mpg would be the high sided ultralight car with no
engine, you just wait till the wind blows in the right firection and
let go the brake. Slow though.

Hey, why not fit it with a sail ?

Graham
 
S

surfnturf

Jan 1, 1970
0
Had an old Renault R8 with a bad battery. Used to bump start it by opening
all 4 doors in a favourable wind.

surfnturf
 
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