Consider the Quasiturbine burning
hydrogen with its
stratification intake, low detonation sensitivity and oil free potential.
Consider also advanced detonation hydrogen combustion mode...
Quasiturbine Hydrogen Type
March 2003 - MIT study says
Improving gasoline and diesel engines is the way to go!
Hydrogen car is no environmental panacea. The hydrogen fuel-cell vehicle will not be better
in terms of total energy use and greenhouse gas emissions by 2020.
If we need to curb greenhouse gases,
improving mainstream gasoline and diesel engines is the way to go.
These results come from an assessment of a variety
of engine and fuel technologies forecasting no real 'breakthroughs'.
(The Quasiturbine having been excluded from the study)
Hydrogen: Not Zero Pollution
Excludes NOx and H2S environmental concerns. Fossil fuel contains carbon and hydrogen. Carbon
combustion produces CO2 which the photosynthesis fixes the carbon into the
biomass, and return the O2 to the atmosphere. Hydrogen combustion
fixes the O2 from the air into water, which oxygen is also liberated back
in the atmosphere by photosynthesis. Since there is not enough
photosynthesis to digest all the CO2, there is not enough either do
process all this synthetic water. Massive hydrogen use has the net effect
of removing oxygen from the atmosphere of our planet and fixing it into
water. CO2 problem is not dissociable from Oxygen depletion. Hydrogen
produced from water (avoiding electrolyses degradation of precious
electricity) will do the same if the oxygen is not liberated to the
atmosphere at the time of production, which is unlikely, considering that
oxygen is precious for industrial process and will rather be fixed by
other chemical process, unless we could not make use of all the massive
quantity produced?
As a result, unless oxygen is made free to the
atmosphere when produce, we can not say that transforming hydrogen
into water vapor (including by combustion or fuel cells) is pollution
free, when 2H does definitively removed
1 precious oxygen atom form the
surface of our planet! (some calculation
show
this is not an issue, but?). Both CO2 and oxygen depletion are
concerns. Synthetic fuel made out of CO2 from the air or
other environment would be more neutral and acceptable - However,
where will the energy to do that come from?
Hydrogen Sources
There is no molecular
hydrogen on the planet Earth, we need to make it!
Energy transformation from one source to another is costly in all terms.
About 10% of the crude oil is consumed to refine gasoline, but up to 35% is
consumed to make methanol.
Transforming fossil fuel in electricity has not been done very efficiently in
the past,
even if new technologies are making substantial progress into the 60% efficiency
range. Fossil fuel to hydrogen has similar lost. Why transforming fossil
fuel-into-hydrogen with such a lost?
Water is the end result of hydrogen combustion. In term of
energy, water is like burned hydrocarbon or ash. The energy content of water is
so minimal that no other liquid is better to extinguish fire! Making hydrogen
fuel from water is energetically the same as making gasoline back from the
exhaust gases (CO2 and water). Transforming precious electricity from fossil
fuel is a severe energy degradation which should not be permitted? (one would get
more hydrogen by swapping its electricity on the world market).
Solar and bio-transformation may be part of the solution
for moderate volume.
The objective is generally to take the pollution (and the poor efficiency) away
from the end users,
but what is the net gain, and at what cost? Environmental human and planet
issues about massive hydrogen production are still open and quite questionable.
Energy transformation is never a good idea. Producing
hydrogen from fossil hydrocarbons means a lost of up to 30 % of initial
energy. Then, to store the hydrogen gas is also expensive in energy of
compression often lost during the relaxation. Following one decade
exploratory on hydrogen, one will rediscover soon that the best way to
store hydrogen is to bind it all around a carbon atom CH4, C3H6...
to form (synthetic if coming from nuclear energy?) gases liquefiable or liquids that one
call hydro- (for hydrogen) -carbon fuel. We will soon rediscover that we
are already within an hydrogen economy, with effective and not so dangerous
hydrocarbon fuel! Sure there is a place for hydrogen and fuel
cells, but not intelligently everywhere... If we have energy available, lets
make synthetic fuel instead of gaseous hydrogen!
Hydrogen or synthetic fuel, the Quasiturbine will not
make much of a difference as it is an exceptional engine for both...
Hydrogen Storage in Carbon Molecules
A good way to store hydrogen is to link it with carbon atom.
This can produce either gaseous, liquid or solid
high energy density products most convenient
for transportation and mobile uses.
When needed, just heat up those carbon-hydrogen molecules,
and the hydrogen will liberate.
For energy production, the hydrogen storage in carbon molecules
is forward and most efficient, because in presence of oxygen,
not only the hydrogen separates and burn producing water vapor
(a so low energy contained product, that it is used in fire extinguisher),
but the carbon atoms will also burn, first in CO
(which has about the specific thermal energy content
of the hydrogen), and which can further burn into CO2.
(also a low energy contained product used in fire extinguisher).
You win twice !
Other hydrogen storage techniques do not seem to be as practical.
This hydrogen carbon molecule storage technique is safe and simple,
and has been appreciated by humans for centuries,
under the name of hydrocarbon fuels !
GM and BMW are taking different routes on the road :
- GM has invested heavily in developing fuel cells
to power electric motors in vehicles,
replacing the current internal combustion engines.
- BMW, on the other hand, is studying burning hydrogen
in internal combustion engines as a more practical alternative.
Internal combustion engine are combined hydrocarbon fuels
"hydrogen extractor and mechanical converter" all at once !
... and the Quasiturbine is most appropriate to do just that in vehicles
Environmental Concerns
Hydrogen and oxygen
combustion gives water, only if no other chemical products are present. A problem
with a conventional internal combustion (IC) engine running on hydrogen,
is that NOx are produced from the air nitrogen (76%), and because they are
very toxic pollutants, this causes significant emissions concerns, and present
solution by cooling the combustion temperature by excess air mixture further
lower the engine power and efficiency. The performing conventional internal
combustion IC engines operated on hydrogen may not easily
meet the future severe environmental emission standards without sophisticated
exhaust treatment. Another concern is
related to the internal combustion IC engine oil degradation in presence of
hydrogen, and the eventual toxic residues safe elimination (not by the exhaust).
Quasiturbine
The Quasiturbine operating on hydrogen has favorable potential emissions
characteristics to meet severe standards, because very little NOx are produced
due to its shorter volume pulse, and because it has the potential to be an
oil-free engine, while having optimum efficiency.
Liquid versus Gaseous Fuel
Ultimately, all fuels get into gaseous state in engine combustion chamber, so one
may be at first legitimate to expect little difference with liquid fuel,
but looking at the combustion process itself is not where the answer stands.
One needs to look at the details of the specific engine intake and dynamic.
Because engines generally prefer a near stochiometric mixture
(except for non-homogeneous Diesel and homogeneous detonation, which both works
in excess of air),
the amount of fuel and air have to be balanced at intake. Lets consider the
gasoline 4 strokes piston engine.
When the intake valve opens, a fix volume is aspirated.
Since the gasoline intaked as liquid droplets does occupy a negligible volume,
most air available can be intaken from the depressurized intake manifold.
In this regard, the gasoline injectors near intake valves are superior to the
carburetors
in permitting more liquid droplets and less gasoline atomization (vapor),
which explains why the modern gasoline injector engines have a higher specific
power density.
Fortunately with the piston engine, when the intake valve closes, there is
plenty of time for the gasoline droplet to atomize
during compression and later even during the combustion stroke,
because optimum pressure is not required until well pass the TDC (top dead
centre).
However, this droplets intake technique is not without adverse effect on
pollution,
but this slow imperfect combustion saves the engine valves from being torched
out!
By opposition, intaking gaseous fuel which occupied a substantial volume, will
leave less volume available for air intake,
and the engine specific power density will be diminished.
To make it short, it is not easy to produce the same combustion condition by intaking liquid or gaseous fuel,
and those condition differences are further apparent in the front flame velocity
(in addition to the specific chemistry characteristics...).
Because of its continuous intake flow and its early and late intake
characteristics,
the Quasiturbine is most able to minimize the gaseous fuel intake penalty.
Detonation - A Must for Hydrogen
In order to do work on a piston, the fuel-air mixture needs to burn at
a speed faster than the piston is moving. The following discussion exclude
hydrogen detonation, which is much different from combustion.
At stoichiometric ratio (no air nitrogen?), hydrogen (uncertain H2
and O2 mixture, with HHO ?) flame speed has been reported up to 3.46 m/s
[11.35 feet/second] which would be nearly an order of magnitude slower
than gasoline 40 m/s [from 70 up to 170 feet/second],
and at lean mixture, the hydrogen flame velocity decreases
significantly. However, engine experts are not
working in stockiometric condition but report
hydrogen-air mixture flame front speed and gasoline-air mixture flame
front speed accordingly.
Stochiometric is an ideal situation which does not occure in IC.
With gasoline, engine do not run exactly stochiometric mainly to
preserve the exhaust valve from overheating, and
to reduce NOx production. Quite the same with
hydrogen in combustion engine. Difference in
comparison is also with the mixture power density because hydrogen is a
gas with a low power density. Per pound hydrogen is more powerful but at
atmospheric density, hydrogen is less powerful compare to gasoline
mixture. Matter may still be open to discussion,
but lower hydrogen flame speed observed in IC engine condition is a
disadvantage shared with most other gaseous fuels. This is why a
detonation capable engine is so important to overcome these limitations.
Source: Mark's Standard Handbook for Mechanical Engineers, Section
9, Internal Combustion Engines, Flame Speed, more at
www.mb-soft.com/public2/hydrogen.html
An average vehicle engine rotating at 2,000 rpm (33 revolutions per
second) produces piston linear speed of 45 feet/second in the
middle-stroke, which is already 5 times faster than the hydrogen flame
front speed ! The fact that a hydrogen-air mixture has a flame front speed
of about 1/10 that of a gasoline-air mixture contributes to explain why
hydrogen engines only run at reduced power and low rpm under load.
However, the detonation mode is extremely rapid and totally removes this
limitation to hydrogen. This is why the detonation mode (not compatible
with piston, but with the Quasiturbine) is somewhat critical for the
future of the hydrogen engine.
Where does the Quasiturbine detonation mode
stands?
Everyone has experienced that lens sun focalization can lit a fire.
As the compression ratio of an engine increases, not only the gas temperature
increases, but also the radiation level.
Combustion goes primarily through at least 3 processes while the compression
increases:
- Primo, at low compression ratio, a hot spot (spark) is required to start a
combustion front flame wave.
This subsonic wave propagates and lits progressively the mixture (this is smooth
deflagration use in our gasoline vehicle).
- Secundo, higher pressure will provoke thermo-ignition, which is a very
non-uniform process liting mixture patches,
and inter-patches combustion being driven +/- by the previous describe front
flame wave.
- Tertio, still higher compression ratio produces uniform radiation driven liting
process,
which is an extremely rapid volumetric combustion (supersonic).
In this case, there is essentially no front propagation, just a powerful light
radiation everywhere...
This last one is the most severe knocking that the piston cannot stand, but it is the
most powerful and perfect way to combust fuel!
In fact, additives used to increase the gasoline octane index
are efficient photon absorbents molecules which prevent this kind of photons
build-up,
and such polluting additives are not needed in detonation mode engine.
Even if shock waves do have the potential to lit a fuel mixture,
photo-detonation does not actually make use of a shock wave within the mixture.
However, the rapid chamber pressure increase does generate a shock wave in the
engine environment,
which could be substantially moderated by a rapid increase of the combustion
volume at that TDC time
(this is what the Quasiturbine does!).
So, why does the piston don't stand the photo-detonation ?
Because it stands high compression near TDC (top dead center) much too long
before producing useful work at mid-stroke.
And why does the Quasiturbine stand it (particularly the QTAC model) ?
Because the volume pulse is 15 to 30 times shorter near TDC, and also because
its higher surface to volume ratio
is moderating the violence of the detonation process, which is almost
independent of the mixture front-wave flame velocity...
Consequently, even if the Quasiturbine can run in conventional Otto mode,
its photo-detonation mode provides the most benefit to fuel efficiency and
environment, both for liquid or gaseous fuel...
Fuel Cell
The Best Current present state hydrogen technologies:
Fuel cells, operating on reformed natural gas, will have very low emissions, but
despite some claims of very high efficiency, their efficiency is at most about 35%
from raw fuel, and half of that in small portable electric motor units (efficiency
falls when getting near maximum output power). Furthermore, they are not readily
available for high power output plants yet nowadays, and they are far from
matching the Combined Cycle Gas Turbine CCGT efficiency, which reaches about
55%. Cost and internal contamination are also limitations.
Finally, if breakthroughs are still expected with fuel cells,
the detonation internal combustion is also
an expected breakthrough with internal combustion engine
which could save half the fuel now consumed in gasoline vehicles
with substantial environment benefits.
Quasiturbine and Hydrogen
Hydrogen is not easily usable in conventional internal combustion IC engine
due to its high inflammability and lower atmospheric pressure specific energy
(30 to 50 % power drop), and generally does require sophisticated and costly synchronized
gas injectors. However, the IC efficiency is potentially competitive.
Nevertheless, four problems subsist: Hydrogen hot combustion in presence of the
nitrogen of air generates NOx; Hydrogen is a vicious gas for all material,
including steel and lubricant; Hydrogen injector does not make uniform combustion;
and storage density still to be worked out.
Quasiturbine characteristics and the environmental
solution: The Quasiturbine pressure pulse is shorter and increases
linearly (as opposed to tangentially at the TDC position like the sine wave of
the conventional crankshaft). This means that detonation at the TDC is not
followed by a long confinement time, responsible for so many broken pistons.
Furthermore, because the pressure pulse is 15 to 30 times shorter at the top
dead center, detonation invariably occurs there and the Quasiturbine is not
synchronization sensitive, and because compression occurs late after the intake
is done, it does not easily backfire. The Quasiturbine geometry allows for
separate intake of air and hydrogen (stratification), low detonation sensitivity
and oil free potential are other favorable hydrogen characteristics.
The fuel cell chemistry will not permit
to make very high density power plant in weight and volume
as shown on this RAGON engine diagram,
like it is easily done with internal combustion (IC) engine.
For many applications from chainsaws or motorcycles, to propeller airplanes,
hydrogen and multi-fuel internal combustion engine will then be most suitable anyway.
The piston
chamber gets hot during the combustion and exhaust, and does not quietly intake
hydrogen mixture at intake time. Furthermore, the piston geometry does not permit good intake
stratification where air and hydrogen can be intaken separately. Rotary engine
presents a less severe situation in this regard, because the combustion occurs to
the area opposite to the intake, and intake can be well stratified by using two
distinct intake ports, one on each rotor side. The fact that the Quasiturbine is
not sensitive to detonation and can stand it, makes it very attractive for
hydrogen operation because hydrogen is the ideal detonation fuel!
In the piston engine, oil is required
for lubrication but also as internal coolant, which is giving little incentive
for oil-free piston engine. In fact, oil is not required for the interface of
the ring and the piston cylinder, but essential because of non co-linearity of
the piston and the connecting rod, which generates an ovalization force on the
piston against the cylinder which must be well lubricated. The Quasiturbine does
not present such unfortunate parallax effect and furthermore, the Quasiturbine
has no oil-pan and its rotor is also an external part, so that the rotor and the
stator are cooled by air flow, and not by internal oil spray. Consequently, the
Quasiturbine has the potential to be a true oil-free engine, which is also expected
to reduce the viscosity friction and increase further its efficiency.
Finally, piston rings are known to brake easily under hydrogen atmosphere due
to the fact that the external perimeter of the ring is in
tension (not compression) while in presence of hydrogen, which favors its fragilisation and
breakdown. None of the Quasiturbine seals is in tension, which means a longer
seals lifetime.
Quasiturbine Hydrogen Markets
The Quasiturbine has the quality to best fit the direct hydrogen combustion
engine. However, the Quasiturbine can have other roles as well in an hydrogen
economy:
Fuel cells:
Some Quasiturbine commercial markets are the same as the market
targeted by fuel cells. Fuel cells operating on reformed natural gas,
will have very low emissions. Demonstration that an internal combustion IC
Hydrogen Quasiturbine Engine also has low emissions characteristics would
provide a low price alternative to fuel cells.
Quasiturbine Pneumatic and Fuel cell :
A perfect Match (using liquid nitrogen) is also quite
an interesting application.
High power density applications:
Generally speaking, the commercial market of natural gas Quasiturbine is
not the same as the market targeted by fuel cells, neither will the
high power Quasiturbines. On the RAGON diagram, the Quasiturbine is the
highest density power plant by weight and volume. Fuel cell chemistry forbids
such a specific high power density (which is very appreciated in the
transportation industry).
Hybrid vehicle:
Hydrogen Quasiturbine generator could be practically adapted to hybrid electric
vehicle. But if such a hydrogen-powered,
hybrid electric vehicle could be engineered, it might well approach the 80 mpg
(gasoline equivalent). For small units, a Quasiturbine Stirling engine could
replace advantageously the second stage for thermal recovery.
Distributed power generation:
Another market for hydrogen Quasiturbine is distributed power generation and
uninterruptible power supplies. It would have fuel efficiency advantages similar
to gas turbine but would be compact enough to be easily located on-site. It could be a cost-effective
option in this market. Because of the multi-fuel capability, the Quasiturbine
seems like an ideal power generator for these applications with hydrogen,
keeping open the multi-fuel option of natural gas, syngas, hythane, etc.
Cogeneration:
The Quasiturbine has an optimum efficiency in a wide range of power output,
which makes it unique for power modulated cogeneration projects.
State of the Quasiturbine hydrogen engine:
No Quasiturbine has yet run under hydrogen fuel. A new generation of
Quasiturbine engine prototypes will be custom made in due time for this purpose.
More Technical...
March 2003 - MIT Engine Recommendation Study
Fuel cells and pneumatic Quasiturbine: A perfect match!
Quasiturbine for vehicles
Hydrogen Energy Center (HEC) http://www.h2eco.org
Canadian Hydrogen Association (CHA) http://www.h2.ca
US National Hydrogen Association (NHA) http://www.hydrogenus.com
International Association for Hydrogen Energy (IAHE) http://www.iahe.org
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