

There is something about this 110 MPG car that does not smell right - adg
http://blogs.howstuffworks.com/2009/06/05/there-is-something-about-this-110-mpg-car-that-doesnt-smell-right/

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robotrout
A lot of it seems to be tricky math. It's not MPG, it's MPGe, the 'e' is for
'equivalent'. However, marketing guys have been playing those games forever,
so no surprises there.

They're claiming E85 has 1/3rd less energy than gas, so they're actually
getting 110*0.66 = 72.5 mpg of E85.

72.5 mpg is not as good for marketing hype, but it's still impressive.

He seems to be playing some games with the acceleration profile as well. If
you 'gun it', you're in 'power mode', not 'efficiency mode', so the mpg
numbers no longer apply. I'm not certain if this is common practice or not in
these kinds of tests. It probably is.

I think he is mainly just taking control of the throttle away from the driver,
and doing a "throttle by wire' system, giving you the most efficient (and
probably painfully unresponsive) acceleration profile possible, when you're in
'efficiency mode'. I'm not sure if that buys him the whole 72.5mpg or not, but
it's in his toolbox. <EDIT: Actually I can imagine such a system that wouldn't
be too bad. When the user makes relatively small acceleration addition
requests with the throttle pedal, you use your efficiency optimized
acceleration profile to give it to him. When the user "stomps on it", because
a truck is about to hit him, then you give him the requested throttle amount.
I can imagine such a system would yield efficiency gains without being too
painful to drive.</EDIT>

Whether there's something else in the engine that gives you the rest of the
efficiency gains, or if that's all of it, remains to be seen.

Of course, we don't know if any of this is real, but if it is, it's a cross
between "real" and "marketing real".

~~~
annoyed
my idea of a fuel-efficient car only has a brake pedal - acceleration is
controlled by a computer

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rjurney
People want to be able to floor it to merge into traffic - its a safety
feature.

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lutorm
Comment #1 below really says it: Even if you have a _100%_ efficient engine,
it takes more energy to propel that un-aerodynamic Mustang through the air 1
mile at highway speeds than you get out of 1/100 gallon of gas. And that's
ignoring rolling friction and powertrain losses. It's a perpetual motion
machine.

~~~
vaksel
I think what they need to do is make an instant on/off engine mated to an
instant on/off transmission.

Right now, even when you are going down hill, the car slows down because of
transmission friction, and you end up hitting the accelerator to maintain your
speed.

If it's instant on/off, they can afford to let the car go in neutral when the
driver isn't accelerating, so you won't use up fuel fighting the transmission.
Same goes for instant on/off engine. If it can be turned on instantly, there
is no reason to keep the engine running when you are just rolling along

~~~
lutorm
At highway speeds, it's mostly aerodynamics, so it won't buy you that much.

Check out this entry in the Tesla Motors blog:
<http://www.teslamotors.com/blog4/?p=70> It talks about the power required to
maintain a certain speed and what's responsible for it.

The Tesla Roadster uses ~ 230Wh/mile to cruise at 55mph. What is that in
equivalent mpg? Gas has 34MH/liter, which is 35800 Wh/gallon. For reference,
that gives 35800/230=155 mpg.

With the given frontal area and Cd of that Mustang, it takes 140Wh/mile to
overcome aerodynamic drag only. Let's assume they have a magic, loss-free
power train. That leaves the tire drag, which should be about the same as the
Tesla since they are both high-performance cars and probably weighs the same
given the Tesla is dragging around all the batteries. The Tesla plot shows
tire drag to be ~60Wh/mile, which adds up to a _theoretical minimum_ of
200Wh/mile, which is 180mpg.

A more realistic assumption is that the Mustang power train (they only talk
about engine so I assume it has a standard transmission) is no more efficient
than the Tesla's, which requires a further 75Wh/mile. This brings us to
275Wh/mile, which is 130mpg.

To reach 110mpg, the engine would thus need a thermodynamic efficiency of 85%.
This is more than twice the efficiency of diesel engines at ~40%.

It can't work.

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cracki
110 miles / gallon = 2.14 liters / 100 km

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vomjom
My suspicion is that they're not counting the ethanol in their MPGe
calculation. They claim to be using E85. In other words, the fuel mixture may
contain about 85% ethanol. Their MPGe calculation probably only counts the
gasoline in that mixture, the 15%.

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Sam_Odio
From their website:

"A Northwest Ohio start-up company is nearly ready to create 2,000 green auto
industry jobs!" [1]

They've received 312,000 orders ... right. For comparison the tesla model S
has received _over 1,000_ orders [2]. An order of magnitude difference. Why
haven't we already heard of these guys?

1\. hp2g.com/articles.html; 2\. www.autobloggreen.com/2009/05/12/tesla-
reports-over-1-000-model-s-orders/

~~~
elai
Because everyone here is focused on Silicon Valley, and Tesla hangs around
there.

~~~
mediaman
For perspective, the new Prius model has a sales target of 100,000 cars in
2009.

Somehow I doubt that some small company with a new engine technology has
outsold threefold Toyota's massively efficient and effective sales, marketing,
and dealership network across the US, _and gone completely unnoticed_ by
mainstream media.

The car business involves a lot more than just the design of the engine or the
car.

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scscsc
I think the trick is the "equivalent" part. If I got it right, they are using
some sort of fuel which provides 1/3 of the energy regular gasoline does.
Which means they are probably doing 110/3 mpg on this type of fuel.

~~~
lutorm
It doesn't matter what the fuel is. You get the same amount of energy out of
it, so it's no easier running 110*3/2 mpg on E85 (which is 2/3 the energy
density) than 110mpg on gas.

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adamBA
its probably gets 110mpg based on the % of fuel that is gasoline. ie the fuel
is 99% ethanol and 1% gas so the car runs a regular 20mpg but because only 1%
of that fuel is gas it gets a magical 2000mpg (20/1%). Their probably doing
something shifty like counting the ethanol as free energy and therefore not
including the ethanol burned in their MPG calcs...

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Confusion
A car that does 377 mpg: <http://www.seattlepi.com/local/351903_needle20.html>

But that means: hardly any chassis, no gearbox, aircraft tires, the engine is
wrapped in asbestos, driving a constant 30 mph, etc., etc.

This car is in the Guiness book of records.

Edit: BTW, I'm not claiming that means the car in this article is also
plausible: if it claims to yield a constant 55 hp, then it can't do 110 mpg.

~~~
lutorm
I think this one is where things will have to go if we want efficency:
<http://www.aptera.com>

