Few seems to know the reason and the
potential limit of Hybrid Concepts?
Hybrid is a complicated way to harvest part of the piston engine losses
that Quasiturbine detonation engine simply does not lose...
Theory - Quasiturbine versus Hybrid
Hybrid versus Detonation
In an interview on December 15 2004, Myron D. Stokes of
eMotion!Reports
wrote (from the press Release):
... Questioned about the Toyota Hybrid System
www.toyota.com and the PAICE
Hyperdrive System www.paice.com , the
president of Quasiturbine Agence Inc., Dr. Gilles Saint-Hilaire explained
that " These are viable approaches for the near term because they are some
of the best practical ways to avoid the low-power-efficiency-penalty of the
today high power vehicle engine, used with only 15% average load factor. But
getting extra efficiency this way requires additional power components and
energy storage, with associated counter-productive increases in weight,
space, maintenance, cost and environmental recycling process". However, in
addition to the Otto internal combustion mode Quasiturbine
www.quasiturbine.com , Saint-Hilaire expects a rapid development of the
photo-detonation Quasiturbine in the next 5 years, taking full advantage of
its unique short and fast linear ramp pressure pulsed properties (This
"knocking" mode is almost impossible for the sinusoidal crankshaft piston
engine to tolerate). Such a photo-detonation Quasiturbine, notes Saint-Hilaire,
would have very little low-power-efficiency-penalty, would be more
environment friendly as it would require low octane additive-free gasoline
or diesel fuel, would be multi-fuel compatible, including direct hydrogen
combustion, and would offer a drastic reduction in the overall propulsion
system weight, size, maintenance and cost". This would tend to make the
hybrid concept much less attractive long term, until such time when fully
electric vehicles will efficiently "fuel" from the electrical grid." ...
Complete Press Release at :
http://quasiturbine.promci.qc.ca/Presse/QTEmotionPR031217.pdf
Low Power Efficiency Penalty
The efficiency of a 200 HP gas engine falls dramatically when used at 20 HP,
because of high vacuum depressurization needed in the intake manifold, this
vacuum reduces as the power produced by the engine increases. The reason for
modern hybrid concepts is to harvest this low-power-efficiency-penalty of
today's high power vehicle engine, generally used with only 15% average load
factor. This is a 50% fuel saving potential in transportation, of which about
half could be harvested the hybrid way.
It is the main purpose of the hybrid car concept to avoid the low efficiency
of gas engine at reduced power. However, detonation engines do not need intake
vacuum as they intake all the air available, and mainly for this reason,
efficiency stay high even at low engine power.
Hybrid Definition
Detonation and hybrid are two different means to harvest the low
efficiency of reduced power piston engine, and both are compatible with
efficient electrical (in-wheel) power train. Detonation engine is however a more
direct and efficient way, and because the « on board fuel » is already a form of
energy storage, detonation engine avoid to re-stock this energy electrically
into batteries. The chemical energy stored in the fuel is degraded when
chemically re-stored in batteries.
Lets make first a distinction between electric vehicle getting their power
from electrical grid and the hybrid concepts. Advanced electric vehicles using
powerful in-wheel digital motors and a set of high efficient batteries
rechargeable from the grid, are not hybrid vehicles (having only one propulsion
system). The idea behind such a vehicle is to benefit from the high electricity
conversion efficiency of public utilities, instead of poor efficiency of onboard
engine. This concept requires larger electricity storage than the Hybrids, and
this is their deficiency today. Ultimately, Hybrid will have to measure to Quasiturbine
detonation engine, which also will have to measure in efficiency to pure electric
vehicles... However, the Quasiturbine detonation engine could continue to stay the supreme
onboard generator for extending pure electric vehicle autonomy...
Hybrid is one way to avoid the lost of efficiency of powerful piston gas
engine when running at low power, the Quasiturbine detonation engine being an
other and better possibility. This is a 50% fuel saving potential in
transportation, of which about half could be harvested the Hybrid way. But
getting extra efficiency the Hybrid way requires additional power components and
energy storage, with associated counter-productive increases in weight, space,
maintenance, cost and environmental recycling process. For now however, the
hybrid concept is attractive, until such time when fully electric vehicles will
efficiently "fuel" from the electrical grid. ...
Hybrid means to have 2 or more active propulsion systems in series or
parallel. Parallel concepts are the most complex and the less long term
versatile, but the mostly used at this time, because engines can add up their
power when needed. Serial concepts mean that only one propulsion system drives the
train, supplied by one source or another. Serial must have total power at the
wheel, but offers more versatility in term of energy storage and handling
management.
Among the confusions about the hybrid cars, many believe that hybrid is mainly to
allow regenerative braking ? It is not. Regenerative braking (electrical,
pneumatic, hydraulic...) could be an added technology on vehicles, and is often
self-included in hybrid concepts. Regenerative braking energy recovery is
insignificant on the highway, little when the batteries are near fully charged,
limited to soft braking (heavy braking exceeding recovery power capability),
and none for now from the back wheels (still waste energy to standard friction
brakes). It is however valuable in intense city driving, and is also of course
an asset of most hybrid concepts. Regenerative braking system can exist
independently from hybrid.
A Cascade of Savings The paradox of today hybrid
vehicle concept is: How much additional equipment can be added to a vehicle
to reach the point where this equipment has worthless net saving effect in
actual application?
Engine efficiency is a large domain of activity which extends far
beyond
engines. The presence of an engine in a vehicle adds accessories and
weights which have to be carried by the power of that same engine (the net
usable power is reduced by the presence of the engine itself). The
presence of the engine is a necessity, but also a factor of inefficiency.
The ideal vehicle would not bother to have an onboard engine! This shows
that not only engine efficiency is important on the bench test, but must
also reduce to the minimum its self-inefficiency in application. It would
be worthless to have a 70% efficiency gas engine for mobile application,
if such a 30 HP engine would weight 3 tons!
Because the Quasiturbine
reduces the weight of typical vehicle power train by over 50%, it does not
have to claim any extra efficiency on the test bench to be most valuable.
Such a reduction of weight on the lifetime of a vehicle means substantial
reduction in power demand, and consequently in fuel.
Engine Exhaust Heat Recovery
Recovering 30% of the engine exhaust heat would allow to exceed most hybrid
efficiency performance.
By placing a hot Quasiturbine into or around an engine exhaust pipe, and
injecting pressurized hot water (steam keep in the liquid state for better
heat transfer), some heat can be recovered into mechanical energy.
A Quasiturbine Stirling or short steam circuit could do similarly! See:
Engine
Exhaust Heat Recovery with Quasiturbines
Electric - Combustion, Hybrid
In parallel concepts (most commonly used today), while the IC engine is at
stop, the electric motor/generator can carry reasonable power demand. To
provide extra power, or when the battery needs to be recharged, the IC engine and
the electric motor generator are geared together. In serial concepts, electric
motors (either central or in-wheel) provide all the train power at all time,
either from the batteries, or from the batteries and the onboard generator
together.
In these two concepts, battery storage capacity needs to be moderate, as they
only intervene for peak power, and long run energy comes from the fuel tank.
Regenerative braking (electrical, pneumatic, hydraulic...) could be an added
technology on vehicle, and is often self-included in hybrid concepts.
Pneumatic - Hydraulic, Hybrids
A hydraulic hybrid vehicle uses hydraulic and mechanical components
instead of electrical ones. A variable displacement pump replaces the
motor/generator, and a hydraulic accumulator replaces the batteries. The
hydraulic accumulator, which is essentially a pressure tank, is potentially
cheaper and more durable than batteries. Hydraulic hybrid technology is being
actively developed primarily in heavy vehicles like buses, trucks and military
vehicles. Other hybrid concepts may also be developed.
Quasiturbine Over Hybrid
Detonation and hybrid are two different means to harvest the low
efficiency of reduced power piston engine, and both are compatible with
efficient electrical (in-wheel) power train. Detonation engine is however
a more direct and efficient way, and because the « on board fuel » is
already a form of energy storage, detonation engine avoid to re-stock this
energy electrically into batteries. The chemical energy stored in the fuel
is degraded when chemically re-stored in batteries.
The Quasiturbine has several intrinsic efficiency characteristics
which add up and reduce the engine energy lost in several ways:
- Because it does not have internal accessories to drive, like the
piston cam shaft and valve train, additional energy is available to the
end users.
- Because of the shaping of the volume pressure pulse, the
thermodynamic of the Quasiturbine can be far superior.
- Because the engine weight is about 1/4 that of a piston, energy
saving can be substantial in many applications.
- Because the Quasiturbine is a high torque low rpm engine, much less
or no transmission gears ratio is needed with corresponding efficiency
increase.
- Because the Quasiturbine can be made of large size, it is an
efficient alternative to utilities for efficient energy conversion
(steam) in
electricity or from co-generation.
- Because the Quasiturbine (AC model with carriages) has the potential
to run in detonation mode, it will not have the low power penalty of the
Beau de Rocha (Otto) cycle, which can provide a 50% energy saving in
transportation application (much superior to hybrid concepts).
Multi-fuel capability is also an important efficiency factor permitting
to use the most pertinent local combustible. Hydrogen high compatibility
is also of consideration for the future.
So, the Hybrid Concepts have been developed to harvest the low piston
efficiency at reduced power. If a new engine does not have such a penalty
at low power, the Hybrid Concept would be of no interest. This is exactly
the objective of the Quasiturbine detonation engine use in transportation.
The development of a detonation engine provides a mean to avoid
that low-power-efficiency-penalty; maybe more environment friendly as it will
require low octane additive-free gasoline or diesel fuel; maybe multi-fuel
compatible, including direct hydrogen combustion; and may offer reduction in the
overall propulsion system weight, size, maintenance and cost. For these reasons
it could be better or competitive with hybrid car technology.
More Technical
Engine
Exhaust Heat Recovery with Quasiturbines
Photo-detonation engine
Quasiturbine in
transportation
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