Peugot to sell hybrid cars that run on gas and compressed air (w/ Video)

Feb 27, 2014 by Bob Yirka report
Hybrid Air. Credit: PSA Peugeot Citroën

Troubled French automaker Peugot has announced that it plans to begin selling cars within a couple of years that use compressed air (nitrogen actually) as a means of partial power for some of its smaller 3-cylinder vehicles.

Using compressed as a power source is not new, even for a car—the reason it hasn't become routine is that it takes a lot of energy to compress air, which makes the whole process rather moot. In this new endeavor, Peugot has sidestepped that problem by using the energy of a moving vehicle to compress in a tank—a piston squeezes it whenever the car is coasting or the brakes are activated.

Technically speaking, it's not air that moves the car, its hydraulic fluid. When power is required the piston in the nitrogen tank works in reverse, pushing hydraulic fluid through a motor that turns the wheels of the vehicle. Thus, the car is constantly moving between adding pressure to the nitrogen in the tank and releasing. It will work best, Peugot reps have told the press, when running in the city, due to the constant stopping and starting.

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The same reps claim the car will cost less than the average gas/electric hybrid, and will allow for achieving up to 118 miles per gallon. It will automatically shift between gas and air and will attempt to run exclusively on air power when the car is traveling at speeds below 43mph. Also, because of the way it's been engineered, the system can be installed on virtually any vehicle and can be seen as a system that replaces the expensive battery needed for current , with something that is cheaper—also it won't need replacing for the entire life of the vehicle. As if all that isn't enough, the car, if successful, will likely be the greenest on the road. When running in air mode, it will have zero emissions.

Peugot has reportedly been working on the concept for two years, investing heavily in the technology, betting that its strategy will pay off in the long run, helping the company finally dig its way out of its financial woes. They expect the first vehicles to be sold with the new system to be available to the public by 2016.

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TheGhostofOtto1923
3.7 / 5 (3) Feb 27, 2014
Nice idea. Why not add a few more tanks and an electric motor to compress more N2 at night? Maybe you could run exclusively on N2 pressure with gas for backup. Or you could have a charging station in your garage, compressing N2 while you're at work, and you pressurize your tanks when you get home.
cjn
5 / 5 (3) Feb 27, 2014
Nice idea. Why not add a few more tanks and an electric motor to compress more N2 at night? Maybe you could run exclusively on N2 pressure with gas for backup. Or you could have a charging station in your garage, compressing N2 while you're at work, and you pressurize your tanks when you get home.


I think the point is to leverage the work the vehicle is already doing while in motion to recharge the tanks. I do also wonder if it is a scalable endeavor, and if it could be partnered with an electric motor instead of a gas one.
Scottingham
5 / 5 (2) Feb 27, 2014
It also seems like the amount of N2 stays constant and its the amount of pressure that changes. The changes in pressure is what gets converted to work for the motors. Otherwise, it would need refills, and the article states it is supposed to last the life of the vehicle.

It would be neat if the N2 could use the gas motor to 'recharge' while parked if its solely used for city driving. Or even better if it could accept a standard outlet and use electricity to 'recharge'.
Mike_Massen
2.2 / 5 (5) Feb 27, 2014
This seems rather odd, as if Peugot haven't exercised this formula for *all* their inter-related systems in the vehicle, what could I possible be missing (shakes head):-

P1V1/T1 = P2V2/T2

especially so in relation to the dynamics of how to manage the rather high & transient heat load movement commensurate with stopping/starting (hmmm)

and looked at how to manage the heat/temp of any exchange/loss/absorption within the vehicle in order to retain the (really useful) heat value as transition to (subsequent use of) motive power, yikes !

Oh deary me !
TheGhostofOtto1923
2.5 / 5 (2) Feb 27, 2014
I think the point is to leverage the work the vehicle is already doing while in motion to recharge the tanks.
I think the point is to create an efficient and useful vehicle and those ideas occurred to me along those lines.
It also seems like the amount of N2 stays constant and its the amount of pressure that changes... Otherwise, it would need refills
Correct. N2 generators are a staple of labs everywhere and arent all that expensive.
https://www.terra...odmmgA5w
-Im suggesting that perhaps the peugeot configuration could be improved to depend principally on compressed N2 by using recharging stations exploiting off-peak electricity in addition to onboard pressurization. I dont know if the tech would need to use pure N2 or not.

Compressed air vehicles are already in use. Many companies are working on new models.
http://en.wikiped..._air_car
TheGhostofOtto1923
1 / 5 (1) Feb 27, 2014
and looked at how to manage the heat/temp of any exchange/loss/absorption within the vehicle in order to retain the (really useful) heat value as transition to (subsequent use of) motive power, yikes !
And how does this compare to heat from headers and exhaust systems mikey? How do gas cars handle that? Most of them have radiators for engine coolant as well yes?

Youll note that the peugeot tanks are on the bottom of the vehicle. Did you know some school buses use exhaust heat to heat their interiors?
krundoloss
4 / 5 (1) Feb 27, 2014
I like the core idea of this design - regenerative braking without heavy batteries or an electric motor. Any form of energy storage, as long as its not too heavy, is great for cars when it is able to capture the energy wasted with normal brakes. Good job Peugot!

Finally someone realizes that regenerative braking is a huge gas saver, even if the process is not all that efficient!
k_m
5 / 5 (1) Feb 27, 2014
There have been pilot projects using rapid transit systems / busses which do similar.

I would also think they'd want to keep the N2 temperature as high as possible so as to keep the valves from freezing when the pressure is released.
Eikka
5 / 5 (2) Feb 27, 2014
N2 generators are a staple of labs everywhere and arent all that expensive.


Nitrogen generators have nothing to do with this system. This is a pressure accumulator that just happens to be using nitrogen as the working medium.

And how does this compare to heat from headers and exhaust systems mikey? How do gas cars handle that? Most of them have radiators for engine coolant as well yes?


Heat exchange has been the unsolved problem of pressurized air vehicles all along. The issue is that compressing any gas to high pressure heats it up, the heat then escapes and leaves you with less energy in the compressed gas than you put in. The gas then cools down when expanding and that cooling causes a drop in pressure which means you get less energy out than was stored in the pressurized gas.

All told, the round-trip efficiency can be as low as 10% unless done isothermally, which in practice means extremely slowly.
Eikka
not rated yet Feb 27, 2014
If any sort of long term storage of energy is desired, beyond a few minutes in an thermally isolated storage tank, the system must include large heat exchangers that blow the compression heat out into the ambient environment and return heat efficiently to the expanding gas. Otherwise the heat loss will render the system very inefficient.

hemitite
not rated yet Feb 27, 2014
One could use some of the heat from the gas engine to heat the N2.
TheGhostofOtto1923
1 / 5 (1) Feb 27, 2014
Nitrogen generators have nothing to do with this system. This is a pressure accumulator that just happens to be using nitrogen as the working medium
You didnt read what I wrote. Take a littlle time and do this. You will see I was talking about home recharging stations using off-peak electricity. I dont know if the system would need pure N2 or not, but if so perhaps you could use generators to supply it.
Nitrogen generators have nothing to do with this system. This is a pressure accumulator that just happens to be using nitrogen as the working medium
But as braking would continue to add pressure intermittently as the tanks cooled it would compensate for lost pressure. Similarly a nighttime charging station in your garage could be regulated to compensate as well.
the system must include large heat exchangers that blow the compression heat out into the ambient environment
-You mean like the radiator the car will already have?? I have a cooler on my transmission.
TheGhostofOtto1923
1 / 5 (1) Feb 27, 2014
If any sort of long term storage of energy is desired, beyond a few minutes in an thermally isolated storage tank, the system must include large heat exchangers that blow the compression heat out into the ambient environment and return heat efficiently to the expanding gas. Otherwise the heat loss will render the system very inefficient.
In watching the video I dont see evidence of this so apparently its not necessary 'for achieving up to 118 miles per gallon.'
Gigel
not rated yet Feb 28, 2014
Pewgot? o.0

hangman04
5 / 5 (1) Feb 28, 2014
@TheGhostofOtto1923

From what i read the article doesn't specify how much autonomy a pressurized tank offers till has to switch on fossil. Maybe trying to keep up the the gas under pressure during the night is a waste of energy since the heat will just escape.

From what i understood this is only iviable when the car is running since the high frequency of breaking will pressurize it on the spot and then the energy stored will probably be used for acceleration asap, basically build up heat won't have time to escape literally.

antialias_physorg
5 / 5 (1) Feb 28, 2014
I do also wonder if it is a scalable endeavor, and if it could be partnered with an electric motor instead of a gas one

If it just uses the energy from coasting/braking then it isn't scaleable. There's a limited amount of energy you can get from that per ride and if the system already captures all that then having a larger system won't add any benefit.

Also electric motors (more specifically: energy recuperation) would compete with the recuperation via compressed nitrogen. So you'd enhance the effectiveness of one at the cost of the other. In electric motors you get the recuperation ability basically for free.
TheGhostofOtto1923
3 / 5 (2) Feb 28, 2014
pressure during the night is a waste of energy since the heat will just escape
You WANT the heat to escape because it prevents you from achieving full pressure. Filling storage tanks in your garage slowly, and charging your onboard tanks slowly during off-peak hours, prevents energy loss through heat buildup and ensure optimum pressure. This could augment the brake-generated pressure which is why pure N2 might still be preferable.
Mike_Massen
3 / 5 (2) Feb 28, 2014
TheGhostofOtto1923 me thinks needs to understand a great of energy is lost as heat when compressing gasses
You WANT the heat to escape because it prevents you from achieving full pressure.
So YOU TheGhostofOtto1923 want the system to be woefully inefficient, you cannot escape P1V1/T1=P2V2/T2,
"slowly" as you put it TheGhostofOtto1923, can't be slow enough, it still represents a loss, try calculus, ie Integration... The maths has a hard time lying, well unless it has commercial incentives sidestepping basic physics...!

Question arises:
"Is it worth all the seemingly complex infrastructure of pressure/(heat) recycling to realistically augment utility for the extra expenditure of those "enhancements". ?

Of course we know ~ 75% of energy from ICE's is lost has heat but, is gas pressurizing the way
to go ?
We already have turbos, thermal, with the latter showing great promise.

TheGhostofOtto1923, when you throw away heat you throw away energy which wasn't intelligently directed
TheGhostofOtto1923
1 / 5 (1) Feb 28, 2014
So YOU TheGhostofOtto1923 want the system to be woefully inefficient, you cannot escape P1V1/T1=P2V2/T2
So mikey why dont you explain this to the peugot engineers who are going to be selling this car in a few years? Maybe you could save them a lot of money. Maybe they will just laugh at you in that condescending way of the french people.
TheGhostofOtto1923, when you throw away heat you throw away energy which wasn't intelligently directed
This is one of the many variables included in the efficiency equations. Apparently it is not enough to discourage Peugot engrs from proudly announcing that their new car will be achieving up to 118 miles per gallon
Mike_Massen
3 / 5 (2) Mar 01, 2014
TheGhostofOtto1923 shows readers amazing naivity
So mikey why dont you explain this to the peugot engineers who are going to..
Why do you so readily accept future commercial claims ?
BMW 'said' they would produce a hydrogen car ages ago, didn't happen & won't !

He went on (sigh)
Maybe you could save them a lot of money..
No, I won't limit their interest in getting government grants & huge tax breaks by spending money on one dubious/costly concept that hasn't been commercially analysed (for sale).

TheGhostofOtto1923 went on
This is one of the many variables included in the efficiency equations. Apparently it is not enough to discourage Peugot engrs from proudly announcing that their new car will be achieving up to 118 miles per gallon
Apparently TheGhostofOtto1923 doesn't know about commercial politics, energy efficiency vs amortised production costs & host of combinations as to why claims don't eventuate, ever.

Physics, economics, business & politics mate - get it ?
TheGhostofOtto1923
1 / 5 (1) Mar 01, 2014
Apparently TheGhostofOtto1923 doesn't know about commercial politics, energy efficiency vs amortised production costs & host of combinations as to why claims don't eventuate, ever.
Well neither does Peugeot either...

"They expect the first vehicles to be sold with the new system to be available to the public by 2016."

-So there's still time! Hurry Mikey, fire off an email before it's too late! Include a link to this thread. Perhaps they will even pay you for saving them lots of francs/euros/whatever.

This is how fortunes are made.

Oh by the way

"The BMW Hydrogen 7 is a limited production hydrogen vehicle built by German automobile manufacturer BMW."

Oh by the way

-You're an idiot.
Gpnum
not rated yet Mar 02, 2014
Any time you use the break, energy is lost in heat.
A system able to recover at least a part of this lost energy to move the car will necessarily reduce gas consumption in urban setting.
Hybrid electric car do that already, but the battery cost a lot more than a compressed air tank and need several replacement during the lifetime of the car.
If the manufacturing is cheap, and the added weight/volume reasonable, it's a good way to increase the gas per mile in urban setting, with no ecological impact.
Eikka
not rated yet Mar 02, 2014
You will see I was talking about home recharging stations using off-peak electricity. I dont know if the system would need pure N2 or not, but if so perhaps you could use generators to supply it.


It is a pressure accumulator. It does not need to be recharged at home or anywhere. The gas is sealed in the cylinder - it does not come out - it is effectively like the coiled spring in a child's wind-up toy car.

You mean like the radiator the car will already have?? I have a cooler on my transmission.


Yes, but much more powerful because the expanding or compressing gas must maintain isothermal conditions. Your oil cooler or engine radiator runs hundreds of degrees hotter than the ambient temp.

Alternatively, you can attempt to insulate the pressure vessel to keep the heat in, but then the energy will leak out in minutes, and that's what is attempted here: recovery of braking energy for just the subsequent acceleration.

There's no provisions for overnight charging.
Eikka
not rated yet Mar 02, 2014
Also electric motors (more specifically: energy recuperation) would compete with the recuperation via compressed nitrogen. So you'd enhance the effectiveness of one at the cost of the other.


Electric regen is highly inefficient at low speeds and starts to consume more energy than it recovers below some critical speed, whereas hydraulic fluid can be pumped all the way down to standstill with no penalty. A pump will pump whether you turn it slow or fast.

Adding an electric motor to the system would only serve to lower the efficiency further.

In electric motors you get the recuperation ability basically for free.


It's an often exaggerated advantage, as it only works while the motor is spinning at a considerable speed. The lower the speed, the more power is spent to magnetize the motor to act as a generator to output a sufficient voltage to recharge the battery, or in case of a PM motor, power is spent in the voltage booster circuit.
TheGhostofOtto1923
1 / 5 (1) Mar 02, 2014
It is a pressure accumulator. It does not need to be recharged at home or anywhere. The gas is sealed in the cylinder - it does not come out - it is effectively like the coiled spring in a child's wind-up toy car.
If you read a little more of the thread you will see that certain municipal vehicles already run off of compressed air. I'm saying that peugot could combine brake recharging with overnight recharging in one system, by increasing onboard capacity.

I thought this was clear? And perhaps this is what peugot ultimately intends to do by first consumer-testing brake recharging as it is the untested segment, and then increasing capacity in later models.
IamVal
not rated yet Mar 02, 2014
"It is a pressure accumulator. It does not need to be recharged at home or anywhere. The gas is sealed in the cylinder - it does not come out - it is effectively like the coiled spring in a child's wind-up toy car."

I normally don't agree with otto, but in this sense he's right. the more we refine the system, the higher pressures they'll be able to hold, and the difference between braking pressure's energy capacity and grid power is the difference between a screwdriver and an impact wrench.
If you make the tanks sturdy enough, the onboard pressurizer won't be able to 'fill' it after a point. that point can be as low as 50% of the tanks breaking pressure making filling it while parking efficient

as far as the heat goes- he's right here too. You can increase your overall gas density by decreasing the compression heat. you can then re-heat it while moving with ambient heat to increase the working pressure. The higher the original density, the more total energy can be harnessed.
IamVal
not rated yet Mar 02, 2014
on the flipside, the higher the heat in the tank, the higher the energy required to add pressure to the system, which a percentage will be lost when the tank cools during downtime.

sounds to me like a 2-3 tank system, A storage and a working tank. one just happens to be hydraulic. I figure if it gets strong enough, both systems will become quasi-hydraulic as the nitrogen will liquify in optimal conditions. compress to liquid on off-peak electricity, heat and expand to gas for working pressure. I'm thinking this is where the nitrogen generator idea came from. he's not offbase.
lee_nhan_54
not rated yet Mar 04, 2014
I have one new method, pneumatic machine, not costs money, anyone , interested
Mike_Massen
1 / 5 (1) Mar 04, 2014
When IamVal claims
the onboard pressurizer won't be able to 'fill' it after a point. that point can be as low as 50% of the tanks breaking pressure making filling it while parking efficient
Then please IamVal explain the physics of how an arbitrary 'fill point' has any relationship AT ALL to an assessment that filling it "while parking" can be efficient ?

It seems you IamVal, have seriously confused a safety issue with the physics of energy transfer, how the heck can you conceive this please ?

Also IamVal claims[q..You can increase your overall gas density by decreasing the compression heat. you can then re-heat it while moving with ambient heat to increase the working pressure. Please IamVal advise:-

1. How do you "decrease the compression heat ?

& then,

2. How do you "re-heat it while moving" ?

& then,

3. Where does heat come from to "..ambient heat to increase the working pressure".

Eg. Was it so damn cold it easily absorbs "ambient heat", how did it get that way fi
Mike_Massen
1 / 5 (1) Mar 04, 2014
Some java oddity when posting, got 2 copies despite "flood control" hey maybe its AGW
and the uneducated non high school going denialists !

*grin*

IamVal
not rated yet Mar 04, 2014
Then please IamVal explain the physics of how an arbitrary 'fill point' has any relationship AT ALL to an assessment that filling it "while parking" can be efficient ?

Should have read "while parked", as in, not trying to be filled by either harnessed inertia or by burning fuel on the road- The most cost effective filling method would be from grid power.. and if your mobile filling system(fuel/intertia) can only fill 1/2 your tank, then filling it using some other means is pertainent.

1. How do you "decrease the compression heat ?
& then,
2. How do you "re-heat it while moving" ?

the answer to both is coolant and a condenser.. we're still a long long way away from magnetic bearings, and I'd assume any vehicle intended for use would be built with a heater (whether it's wicking heat away from a combustion engine or created purposefully).

it WILL be cold enough to absorb 'ambient heat' when vaporizing.
I mean, if you don't understand.. maybe you need more engineering
IamVal
not rated yet Mar 04, 2014
for instance- liquid nitrogen is usually thought of as extremely cold, but anyone with a 5th grade deploma should know that it's not cold but just highly pressurized. If you handle a bottle of liquid nitrogen capable of handling the pressure at room temperature, the container won't be 'cold' but the liquid still has a very considerable cooling capacity when depressurized. (because it 'absorbs abient heat'- Anything hotter than it's current temperature density)...
you pressurize the nitrogen to the point of liquification, by pressurizing and cooling, then using whatever heat is available you can increase the payload without extra work. This last part wouldn't be required but does contribute to conversation.

also, more than likely, the stationary filling device would be more efficient calorie for calorie.
these are not things they're talking about and certainly not required, but will eventually happen.
It's not a question of whether it's nessessary but how to get the most bang
Mike_Massen
1 / 5 (1) Mar 07, 2014
IamVal showed immense misunderstanding and sheer ignorance with
it WILL be cold enough to absorb 'ambient heat' when vaporizing.
I mean, if you don't understand.. maybe you need more engineering
The MASSIVE point you are missing is energy flow to cool/heat takes energy, the amount of transient energy from braking to acceleration is bound by "impulse power", of course it can be done to a degree but, from an economic analysis its doubtful the energy density is high enough and the cost of adding all the material for the expected small gain is not efficient. The claims they make have yet to be tested but, bear in mind car companies routinely get grants to explore claims along with tax credits.

Eg. BMW & the hydrogen car, a thermodynamically bad engineering decision...

Education in thermodynamics and re Peugot re Statistical Mechanics & heat flow analysis is absolutely essential.

So IamVal, please study up on real physics & engineering before you are tempted again to comment !

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