

Peugeot Bets on a Different Kind of Hybrid Car - vdondeti
http://www.nytimes.com/2013/03/02/business/global/peugeot-bets-on-a-different-kind-of-hybrid.html

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stcredzero
Isn't compressed air somewhat like capacitors? So-so energy density, but great
power density? It's supposed to be great for a burst of speed, but not for
lots of range.

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mistercow
Perhaps, but my understanding is that gas engines are really very efficient at
keeping you at speed; it's accelerating from a stop where you use a lot of
fuel. So a burst of power with little range can win out if it adds a lot less
mass to the car than the battery and electric motor in an electric hybrid.

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ams6110
Yep, it's a completely mechanical way to recover the energy expended in
braking and apply it to getting the vehicle rolling again. In this way the
gasoline engine is mainly used to maintain speed and climb hills.

Other experimental vehicles have used flywheels to capture braking energy, but
the advantage of compressed gas is that it can store the energy indefinitely
(assuming no leaks).

Sounds like it could be more efficient and reliable than the electrochemical
process that electric hybrids use, with less weight and environmental concerns
related to battery manufacture and disposal.

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pkulak
Well, there's always a risk when you're storing energy. In this case it would
be explosion. Could be a very small risk, though.

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pilap82
I had the same "concern" but they say: The energy stored in the nitrogen tank
is small — equivalent to only about five teaspoons, or a couple dozen cubic
centimeters, of gasoline

So I guess that the explosion of a tank full of "about five teaspoon" should
not wreak too much damage :)

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DeepDuh
What I gather from the article it's not the stored energy that's of some
concern, but the 250 bar nominal pressure in the tanks - a rupture might lead
to metal splinters flying around. However, they claim that the car's
underfloor is enough shielding. I'd say let some independent safety tests
figure that one out.

So far I think this is a very promising concept - I was always weary about
electrical hybrids because of the use of rare earth metals and the
environmental impact in some regions because of that. Putting some nitrogen
tanks and mechanical/electronic bits in a car to achieve the same effect for
city driving seems like a big winner - mass produced I'd think you could make
those cars only minimally more expensive than normal gas powered ones.
Electrical Hybrid car prices, meanwhile, don't seem to scale down much.

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gus_massa
Here in Argentina ~1/5 of the cars use compressed natural gas (mostly methane)
tanks at 200 bars, because it is cheaper than gasoline. I don't remember any
horror story of a crash, and these cars are generally considered almost as
safe as the usual cars. The main drawback is that the tank is very big and
uses half of the back trunks.

More information: <http://en.wikipedia.org/wiki/Compressed_natural_gas>

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StavrosK
We do the same in Greece, the tank is 50-60 liters (not sure if that volume is
when the gas is at STP or compressed), though, and takes around the room of
the spare. That's also where they put it.

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rikacomet
Oh gosh, I don't want to complain, but I reported this about 1 month ago, and
it didn't even get 1 point.

It seems different timezones, have different taste :P hehe

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gus_massa
I saw you submission last month. The problem is that it looked like direct
copy of an AFP new that looked like a direct copy of a press release of
Peugeot, so it was difficult to know how interesting the new method was and
how much was only hype.

The NYT has a little more credibility and the article seams to be written more
independently, but until there are some more real use case reports with the
new cars it's still difficult to separate the reality from the hype.

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rikacomet
Yeah, I see what you mean. I will remember that in future. Cheers, and thanks
for reply.

