Compressed Air Car with
Quasiturbine Pneumatic Engine
(Quasiturbine air motor)

Since the Quasiturbine is a pure expansion engine
(which the Wankel is not, neither most of other rotary engines),
it is well suitable as compressed fluid engine - Air engine or air motor.
(For the steam engine, see )

The Quasiturbine team do not generally get involve in engine integration, but here are some perspectives:


This include an example (in French) 


L'APUQ conduit des travaux d'intégration pour la propulsion d'un go-kart
avec une Quasiturbine QT75SC pneumatique.
Voir détails sur leur site :
October 28, 2004 - WORLD PREMIÈRE

Jean-Luc Mongrain meet with the reporter Jean Lajoie (in French)

Video at :



Pneumatic systems have a big advantage: they are cheap and don't require impractically expensive battery maintenance.
A 40kg 25 cubic meter compressed air cylinder the same size as
the steel types used in natural gas vehicles can store 4 kw-hr of energy.
Assuming (conservatively) that 50% can be recovered, we have a real world density of 2kw-hr/40kg = 50 watt hours per kg.

This is much better than the best lead acid lead acid batteries which can achieve 50 watt hours
only by 100% discharge: something that cuts battery life to only a dozen or so cycles.
The power to weight ratio of compressed air systems is quite high: Higher than most electric system.


The Korean inventor energine has developed an electric & pneumatic hybrid car.

A compressed air engine can provide great torque and power for its weight
but only for a short time because not only does the air run out but the engine
(unless provided with elaborate heat exchangers)
becomes cold due to the adiabatic expansion of the air and loses efficiency.
A compressed air motor provides for powerful acceleration while not adding to system weight.

The compressed air motor and electric motor are interconnected by clutches
so that the car can recharge its air reservoir and its battery and operate separately or together as required.

Electric-Petrol Hybrids are complex and expensive and still require exotic materials.
The air-petrol (or diesel) hybird may be a cheaper option that overcomes these limitations.

UCLA Study Suggests Air Hybrid Car Could Improve Fuel Efficiency

Air hybrid cars could bring big fuel savings for city drivers,
according to a recent study released by UCLA engineers. Experiments
based on modeling and simulations showed that the air hybrid engine
improved fuel efficiency by 64 percent in city driving and 12 percent
in highway driving. The study also suggested that by adopting the air
hybrid approach, car-makers could avoid some of the manufacturing
costs associated with the more common electric hybrid design.

The air hybrid engine design concept. Tsu-Chin Tsao, professor of mechanical and aerospace engineering at
the UCLA Henry Samueli School of Engineering and Applied Science,
and graduate student Chun Tai have been collaborating with engineers at Ford Motor Company
and consultant Michael M. Schechter for more than a year on an air hybrid vehicle design that uses a camless valvetrain.
Tai presented the team's findings at the Society of Automotive Engineers World Congress in March 2003.

Like its cousin the electric hybrid, air hybrid vehicles are being explored
as a more fuel-efficient means of traveling the nation's roads, especially in urban areas,
where stop-and-go traffic leads to a wasteful use of gas.
During a typical day of city driving, fuel energy used to accelerate the vehicle is partially wasted during deceleration,
when kinetic energy is converted into heat in the friction brakes.

Fuel economy could be greatly improved, say researchers, if that braking energy could be captured,
stored and later used to help the vehicle speed up, for instance.

To make the air hybrid design work, Tsao introduced a few clever modifications to a traditional 2.5 liter V6 engine,
including a valve design that allows the engine to not only burn fuel more efficiently,
but to compress and expand air captured during braking as well.
When it is compressed, air can store energy that is neither toxic nor explosive.
Once the air is expanded, the burst of energy that is released can be used to help accelerate the car.

The concept is closely tied to that of electric hybrid vehicles,
which are becoming an increasingly well-known alternative to traditional automobiles
and have already proven capable of reusing braking energy.
While still fuelled by gasoline, the electric hybrid vehicle's engine and transmission combination is augmented
by an energy conversion and storage system housed in a black box under the car's hood.
This collection of sophisticated electronic components captures brake energy,
stores it as electricity and then releases it when it is needed.

The additional hardware required to make it work includes a battery and a supplemental electric motor,
which adds weight to the car and drives up costs.
Manufacturers are forced to reduce weight in other ways.

"Automobile manufacturers are turning to more expensive lightweight materials like aluminum
to compensate for the added weight involved with the electric hybrid approach," said Tsao.
"With an air hybrid you don't have to worry about that."

Thanks to Tsao's innovative valve design, the air hybrid can achieve similar fuel efficiencies
but needs only an air storage unit weighing no more than 30 kilograms.
Because it does not need a second propulsion system,
the air hybrid model, bottom, is less complex than the electric hybrid model, top.

"The air hybrid does not require a second propulsion system," said Tsao.
"This approach allows for significant improvements in fuel economy without the added complexity of the electric hybrid model."

The UCLA researchers avoid the need for an additional motor by introducing greater functionality into the engine's valve system.
During conventional combustion engine operation, the camshaft causes the intake and exhaust valves to open and close
in a synchronized fashion to let in air and fuel and to let out exhaust.
The camshaft is designed to perform in a predictable and fixed way.
The same operation occurs over and over -- nothing more.

Tsao's industrial collaborators designed an electrohydraulic camless valvetrain system
that allows for more variable valve operation, with greater control over when a valve opens and for how long.
Tsao developed methods to precisely control the valve operation over a wide temperature range.
This, in turn, makes it possible for the traditional engine to do more than just burn fuel.

"We wanted the engine to compress air and charge the compressed air back to the engine," said Tsao.
"So we replaced the cam shaft with an electronically-controlled valve system."

Tsao's proposed valve system allows the engine to operate in four different modes.
When a vehicle decelerates, the engine is used as an air compressor to absorb the braking energy and store it into the air tank.
Whenever the vehicle stops, at a red light for example, the engine is shut down.
Once the light turns green and the driver touches the accelerator pedal, the engine is started by compressed air.
As the car speeds up, the engine is used as an air motor to drive the vehicle until the compressed air is depleted,
at which point the engine is switched to conventional combustion mode and begins burning fuel.

The concept of driving a vehicle with compressed air is not new.
In fact, a compact version of an air-powered car was introduced at the Paris Auto Show in late 2002.
That car had a four-cylinder piston engine powered only by compressed air that is stored in an on-board air tank.

Road tests are needed to prove Tsao's concept, and other challenges need to be addressed
before air hybrid vehicles become widely accepted.
"We want to optimize the size of the air storage tank, and begin testing the air hybrid operation using a diesel engine," said Tsao.
As consumer demand grows for more environmentally friendly road vehicles, drivers may one day find themselves riding on air.

Chris Sutton 07/21/03

Opponents to air car and other alternatives miss the point when ignoring our fundamental human society problem :
We use to much energy and power ! ...from the Quasiturbine researchers team 04.09.01

One day, once we will accept (or be forced to accept) to use much less energy and power,
Internal combustion 1/2 HP engine will still be one of the solution,
as well as electric batteries, air car, Stirling, solar, nuclear pellets, coil springs or twist rubber band,
gravity energy storage, human power, etc.

Researches are also about to give solutions to future context.
There will be room for all sorts of solutions.
Hopefully, outrageous human energy waste will not be for ever...
Instead of blaming alternative energy solutions for their weakness, fight the present non sense energy opulence...
and talk about the weakness of our underground crude oil parasitic society.
Accept that some visionary peoples try even now to oppose menu alternatives to the 300 HP gas piston engines !
Let's keep innovating and give them our encouragements, don’t play the establishment game...

Petrol is a net energy source only to those who think it is OK to still pump petrol from the planet underground reserve.
Based on long term, petrol products are not energy sources, but energy carriers just like the hydrogen or the synthetic fuel.
The difference is only that it stores energy from another era !

The establishment and government (and many others) like you to think that it is Ok and correct
to express the efficiency form "well to wheel".
This is very wrong and incomplete, because it implicitly means that you start efficiency calculations from an existing product,
and after it has been stolen from the underground (foreign) reserve.
Once the human will have to make its synthetic fuel from honest planet surface energy transformation activities,
he will soon discover that compressing and expanding air is as efficient as and less complicated
than making synthetic fuel for its mobile applications, and that the size and weight of the air reservoir
is quite convenient compared to a mini synthetic fuel plant !
In overall complete scenario, planet surface human made fuel is not providing good efficiencies,
and in no way in the 10 % range. So please be fair to alternatives...

Many are disappointed that air car promoters do not tell the truth straight and complete.
But who does ? Not the car industry, not the battery makers, not the hydrogen investors, not the nuclear enthusiasts,
not the solar or windmill fans... Not even probably the Quasiturbine team ?

When a country produces too many experts in efficiency,
it does induce an efficiency deficiency population attitude, which favours efficiency concept like :
Let others do it! Steal it from others! Let's wait and see!
Being too efficient can mean doing little innovation... That's probably the way America is giving up its car industry ?
I am not saying this is not natural to be lazy, since the food chain (from which the human is part)
makes extensive use of those principles :
Wait and let the fish hunt : cook it when it becomes larger !
...But sometimes, others catch the fish, and you are left with little free lunch ?

Quasiturbine team is not in conflict of interest on this matter
because even if the Quasiturbine could be a good substitution for the 300 HP internal combustion car engine market,
the Quasiturbine is as well a good solar steam engine, an efficient power modulated air motor,
an efficient Stirling cogeneration engine, and the best engine for hybrid vehicle onboard generators
or extremely efficient photo-detonation engine... Quasiturbine win (or lose) on all sides !

Remember, petrol is a precious feed stock available for material transformation,
of which the energy applications are often the worst non recyclable uses.
Remember our fundamental human society problem : We use to much energy and power.
Let's save some ! ...and give-up about the stolen underground fuel efficiency 30% bias reference...

Compressing a gas produces both pressure and heat.
Excellent reversibility can be achieve if one keeps both the pressure and the heat stored together.
However, heat can be removed from the gas by cooling it
(a necessity if multi-stage higher pressure is desired, and sometime heat can be usefully dispatch),
and heat can be given back later, sometime from a free heat sink (ambient) during relaxation,
to still produce a fairly good reversibility.
For short term uses, it may be beneficial to store both the pressure (moderate) and the associated heat.

Storing both the pressure (moderate) with its associated heat could be appropriate
for example in the case of mining pneumatic locomotive or city subway,
where the pneumatic wagon could be refill every few hours, not to say partly refill from the braking energy recovery.
Pneumatic remove the high voltage subway hazard,
and allow better conditioning the air purity by releasing dry air, which is most suitable to reduce subway moisture.
Depending of the voluntary heat lost on the ground processing pressure plant,
subway gas relaxation could further cool down the ambient air, a great advantage on summer !

When a gas at room temperature expands, it produces energy in two forms : pressure work and cooling,
which energies add up to quite an excellent reversibility.
Most people ignore or discard the powerful adiabatic cooling,
but it could be of direct interest, like in conditioning the subway air.
What is nice about expanding compressed gas is that the cooling adiabatic energy
can be converted into mechanical work providing some heat can be given
to the gas during relaxation (almost magic conversion !).
If this heat can come from a free ambient heat sink,
then the isothermal expansion acts locally as a sort of mechanical energy amplifier,
while total energy is conserved considering earlier compression.
If added heat is coming from the system (boiler...),
then, isothermal expansion is a good way to increase the specific power density of the machine,
but does not provide a net additional energy output !

But keeping the heat (higher temperature) in an air tank reduces it energy capacity ?
This would insure a good reversibility all the time,
but of course the isothermal mechanical amplification will not be as easy (impossible with ambient heat),
which would in fact reduce the local mechanical work done by the same reservoir capacity.
If higher level heat is still apply to the gas relaxation,
then the same mechanical work could be extracted (but with some residual heat lost at exhaust).

The energy density comparison are distorted unfairly (by ignorance)
by those who keep stating that gasoline contains 9000 w-h/liter.
The truth is that to get such an amount of energy from a full car tank of gasoline,
one need to have about 2 tons of oxygen !
Lets assume you carry onboard the needed oxygen,
then your real power density (in weight and volume) will fall to what they call ridicule low level...
Not only do we steal the petrol product from our underground reserve,
but our vehicle further steal the air while underway from our atmosphere.
Should we oppose petrol unfair results to the alternative energy solutions !
This is of course not a fair way to describe the true reality...
Similarly, we should stop referring to IC engine peak 30 % efficiency which is far from average in use engine efficiency,
where most vehicle hardly reach 9 % efficiency form fuel to wheel (which is in the range of many interesting alternatives).

Within a compressor in adiabatic process, pressure increases for 2 reasons :
because of volume reduction and because of temperature increase.
Since the temperature is keep constant in isothermal process, the pressure does not increase as much,
and the work done by the compressor on the gas is much less.
Said otherwise, the total amount of heat continuously removed during the isothermal compression is less than
the heat accumulated at the end of an adiabatic compression.
An other important difference is that while adiabatic compression
produces valuable high temperature grade heat suitable for Stirling recovery (coming from extra compressor work),
isothermal compression produces worthless low grade heat unfit for any heat recovery.

Consequently, it is not possible to extract mechanical energy from ambient heat,
conform to Carnot principle that 2 different temperature sinks (heat flow) are needed to do so !
However, both compression-relaxation cycles, either isothermal (continuous instantaneous heat removal)
or adiabatic (assuming no heat lost) are equally highly reversible.
Furthermore, if someone leaves you the choice between say,
a 100 degrees delta T over the ambient temperature and the same 100 degrees delta T under the ambient temperature,
which one would you preferred in term of mechanical energy conversion efficiency ?
Not only Carnot tell us the limit of thermal to mechanical efficiency is proportional to delta T,
but he also state that for a given delta T, this conversion efficiency decreases with increase of the temperature zone.
This is why liquid nitrogen evaporation and thermalisation to drive an air motor can provide higher conversion efficiency
than higher temperature large delta T of hot steam .

Energy alternatives are apparently loosing against unfair petroleum pumping
and free atmospheric air oxidation, so is the planet loosing.
It is always easier for someone to make a good living out of stolen money, than out of it honest earning,
until such a time that he imprisons himself...
This is what we are all doing by using underground petroleum.


Heat pumps are heat movers.
If someone mixed-up the heat he moves with the machine input energy,
he gets a useful artificial over unity efficiency that no one seem to contest!
Mechanically speaking, heat pumps compressors and air motors are identical and complementary,
and over unity are motor is unfortunately not possible, notwithstanding the artificial over unity compressor.

Here is why it is not mechanically possible :
The environment offer one single heat sink T(0) which an heat pump compressor can split in two T(-) and T(+)
with an over unity efficiency (?).
Now, let an extremely efficient Stirling engine makes work from those two heat sinks,
and cash in the over unity heat pump efficiency ?
Unfortunately, Carnot will allow the pair of heat sink to cancel out at environment T(0)
and give out no more mechanical energy than the heat pump got in the first place...
At most, you get good reversibility, but no gain.
Carnot allows over unity heat pumps but takes back all profits later !
Getting net mechanical energy out of one sink is not possible, never mind the constraints,
but making use of the free heat (trucked cycle) is.

A comment about EXERGY
Because it does favour thermodynamically matching energy sources with energy needs and applications,
all exergy considerations strongly support the development of a multitude of energy alternative technologies.
The 9000 W-h/l (gasoline) unique universal energy source provide poor thermodynamically matches
with most energy needs and applications...
and only a large variety of technologies are going to provide an optimum exergy world !

It is worthless to develop  alternative energy technologies with the objective to match comparisons
with stolen underground petroleum and stolen atmospheric oxygen.
No one is doing it to sustain SUBs !
We show interest in alternative energy to give more long term sense to the live on our planet,
and to preserve it and humanity for an other million years...
Anyway, we will be force to do so soon, so why not now ? ... Who is against planning phasing out and in ?


Air motor power can be increased if heat is given to the air to further increase its volume
and strongly reverse the nefast adiabatic cooling, providing the air motor can accept this kind of hot air ?
I just want to recall that this was exactly the idea of Joule (also Brayton)
when they designed their cycle of turboshaft jet engine !
The best way to add heat to air between the compressor or the storage air tank
and the air motor is to inject the fuel into that same air flow and burn it in-situ.
To accept that hot air/gas flow, conventional hot turbines have been developed,
and similarly, Quasiturbine hot air motor could be developed as well...
with efficiency and power modulation advantages over conventional hot turbines.
Turbo-shaft jet engine are noting else than large heated air motors carrying their own compressor !
See :
One of the most efficient and high specific power engines of all time !

Notice however that ambient temperature air storage competes against 1/10 of the gasoline 9000 kW-h/l,
because even if optimum IC engine exceeds 30 % efficiency,
the average efficiency from gas tank to wheels in actual vehicle use barely reaches 9 % !




Quasiturbine Pneumatic and Fuel cell :
A perfect Match (using liquid nitrogen) ! 

See :

A Thermo-Pneumatic Quasiturbine Locomotive
(with addendum on subway operation)
See :

A project intended to make a demonstration liquid nitrogen motorcycle
is in planning at the Cegep de Rimouski, Québec (projet temporairement ? suspendu au printemps 2002)
Concours Force Avenir


Quasiturbine pneumatic-steam model QT50SC (Without carriage) 
Usable with intake sustained pressure as low as 20 to 50 psi!



L'APUQ are doing go-kart Quasiturbine integration work with the Quasiturbine QT75SC pneumatic.

MDI - Miguel Celades Rex
MDI Official representative for Spain, Portugal, Latin America, UK and Canada (English) (Español) (Português)

The Korean inventor energine has developed an electric & pneumatic hybrid car.

UCLA Study Suggests Air Hybrid Car Could Improve Fuel Efficiency

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Quasiturbine Pneumatique Inc.
Casier 2804, 3535 Ave Papineau, Montréal Québec H2K 4J9 CANADA (514) 527-8484 Fax (514) 527-9530