U.S. patent application number 12/230004 was filed with the patent office on 2010-02-25 for miniaturized waste heat engine.
Invention is credited to Claudio Filippone.
Application Number | 20100043432 12/230004 |
Document ID | / |
Family ID | 41695049 |
Filed Date | 2010-02-25 |
United States Patent
Application |
20100043432 |
Kind Code |
A1 |
Filippone; Claudio |
February 25, 2010 |
Miniaturized waste heat engine
Abstract
A closed loop vapor cycle generated by a special device formed
by heat transfer and a vapor expander means it is utilized to
convert waste heat from conventional power systems into additional
thermodynamic work, thereby improving the overall power system
efficiency. Superheated vapor (i.e. steam) is instantaneously
produced inside special energy transfer means where waste heat is
converted into fluid energy with desired thermodynamic properties.
The superheated vapor is then converted into mechanical energy
through special work-producing units (expanders), thereby returning
a significant fraction of the energy contained in the waste heat to
the power system. When the power system under consideration is an
internal combustion engine the energy contained in the exhaust
gases (waste heat) is transferred back to the engine through one or
more expanders directly or indirectly coupled with the engine load.
The energy extracted from the waste heat can also be added back to
the engine by means able to enhance the availability of oxygen
(oxygenators) during the combustion. In this case, the engine also
improves its dynamic response and reduces its production of toxic
emissions. If the engine utilizes heavy fuels (i.e. diesel
engines), this device completely eliminates the formation of the
highly toxic particulate (black smoke), while significantly
improving engine performance. The cost of the energy required to
operate the device proposed in this invention is zero since it only
recuperates and utilizes energy in the form of heat that is
normally discharged into the environment.
Inventors: |
Filippone; Claudio; (College
Park, MD) |
Correspondence
Address: |
Claudio FILIPPONE
8708 48th Place
College Park
MD
20740
US
|
Family ID: |
41695049 |
Appl. No.: |
12/230004 |
Filed: |
August 21, 2008 |
Current U.S.
Class: |
60/616 |
Current CPC
Class: |
F02G 5/04 20130101; Y02T
10/12 20130101; F02B 41/00 20130101; Y02T 10/166 20130101 |
Class at
Publication: |
60/616 |
International
Class: |
F02G 5/02 20060101
F02G005/02 |
Claims
1. A waste heat recovery system for internal combustion engines and
configured to cool down exhaust combustion gases while converting
their energy to increase engine efficiency and mitigate the need
for increased heat rejection capacity, comprising: a first heat
converter configured to transfer heat from engine coolant to a
working fluid, a second heat converter to transfer heat from
combustion gases to the working fluid, a third heat converter to
transfer heat from the working fluid to the environment, a flywheel
to convert the working fluid energy to supplement engine power, a
pump to circulate the working fluid, a turbine generator to expand
the working fluid a bypass three-way control valve to control flow
of working fluid.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention is characterized by a combination of
vapor-to-mechanical energy converters driven by rapid heat transfer
means able to instantaneously transfer energy from the products of
combustion, or any heat source, to a thermodynamic fluid
circulating inside an independent loop. This fluid moves inside the
loop mainly as a result of its own expansion and transfers its
energy to mechanical means through thermodynamic work-producing
units or expanders. In this manner, the various components of this
device constitute a special Miniaturized Waste Heat Engine (MWHE)
able to recuperate and convert waste energy from combustion or heat
sources into useful energy. By returning a significant fraction of
this recuperated energy to the power system (for example in the
form of mechanical or electrical energy), the usually unavoidable
heat discharge into the environment is minimized, while pollutant
emission can be significantly reduced at no energy cost for the
power system.
[0002] To simplify the description of the working principles and
methods of operation of this invention, an internal combustion
engine (fueled with heavy or non-heavy fuels) is from now on
considered to be the power system. However, any power system
utilizing heat sources and producing waste heat as a result of
their operation could utilize the techniques and methods described
by this invention.
[0003] When this invention is applied to an internal combustion
engine, the energy of the exhaust combustion gases (high
temperature and mass flow rate) is converted into additional
horsepower transferred directly to the engine load, via the engine
crankshaft, and/or indirectly via special engine intake oxygen
enhancing means.
[0004] The MWHE contains one or more vapor-to-mechanical energy
converting systems, referred to hereafter as expanders; one or more
instantaneous heat transfer systems, referred to hereafter as
converters; one or more instantaneous vapor collapsing systems,
referred to hereafter as imploders; and one or more air/oxygen
enhancing systems, referred to hereafter as oxygenators.
[0005] In general, the MWHE is formed by one or more converters
coupled with a series of expanders including a vapor condensing
system, or imploder, so as to form a thermodynamic cycle. A
converter (or multiple converters) returns the recuperated energy
from the exhaust gases through one or more expanders in the form of
mechanical energy, adding it to the power normally generated by the
engine. Another converter (or the excess recuperated energy of a
single converter) allows the pressurization of the engine intake
manifold through the oxygenator, thereby providing excess oxygen to
the air fuel mixture independently of the engine rotational speed,
or revolutions per minute (RpM). By utilizing this particular
oxygen enhancing feature, the engine performance can be
significantly improved since air/oxygen is virtually pumped into
the engine at all times, regardless of the RpM, at no cost. If this
device is applied to a diesel fuel engine, the production of highly
toxic particulate is almost eliminated since excess oxygen is
always present during combustion, even when the engine is
accelerating from idling speeds.
[0006] Therefore, the main application of this thermodynamic engine
can be seen as an anti-pollution system, especially when applied to
heavy fueled engines, but also as a device able to significantly
improve engine performance while reducing fuel consumption. Again,
it is important to emphasize that the source of energy of this
invention is constituted by heat that is normally irreversibly
discharged into the environment.
PRIOR ART
[0007] Engine intake air-enhancement-systems are normally
characterized by centrifugal turbo-compressors, or turbo-chargers,
and by positive displacement air compressors. The centrifugal
compressors are devices utilized to provide excess air to the
engine allowing increased power output and generally improving the
combustion. These devices improve the overall engine efficiency
because they recuperate a fraction of the kinetic energy and
pressure energy contained in the exhaust gases produced during
combustion. Centrifugal compressors are widely used in Internal
Combustion (IC) engine applications since they show reasonably good
efficiencies when they operate at the proper speeds, are reasonably
rugged, and last for the entire life of the engine. Air compressors
for IC engines are generally formed by two counter-opposed sections
containing the Exhaust Gas Wheel, "EGW," and the Compressor Wheel,
"CW," connected by a common shaft. The EGW converts parts of the
kinetic and pressure energy of the exhaust gas into shaft power.
Since the CW is also mechanically connected to the same shaft, it
converts the shaft power provided by the EGW into air pressure at
the discharge of the CW. In this manner, the engine intake
manifolds become pressurized and more air/oxygen is available to
the engine. Thanks to these devices, it is possible to increase the
amount of fuel injected in the combustion chamber and increase the
overall engine power output. Unfortunately, the efficiency of the
centrifugal compressors is optimized only for a significantly high
range of rotational speed of the CW (generally greater than 30,000
RpM). Such speeds are only reached when the mass of exhaust gases
(mass flow rate, grams-per-second), matches the optimized EGW RpM,
so that the maximum torque is transferred through the shaft to the
CW. This unavoidable sequence of events creates the conditions for
a delay, called "turbo-lag," imposed mainly by the fluid-mechanical
inertia of the exhaust gases, the mechanical inertia of the EGW,
CW, and many other factors. Due to the fact that the exhaust gases
are a consequence of the combustion process, the engine experiences
a significant delay between the time the fuel is injected and the
time the proper quantity of oxygen in the combustion chamber is
made available by the compressor. This delay provokes a severe drop
in engine performance during acceleration, particularly from idling
to higher RpM. In fact, during these phases there is not enough
oxygen to complete combustion, therefore the production of
pollutant emissions is significant while the engine performance is
impaired. This condition exists for several seconds every time the
engine accelerates and it becomes even more pronounced when the
engine is severely loaded.
[0008] Normally, if the engine is idling and the accelerator pedal
is suddenly pressed, the fuel appears inside the combustion
chambers almost instantaneously, but the availability of oxygen is
completely insufficient to complete combustion. Eventually, the
engine RpM changes from idling to the desired speed and an
increasing mass flow of exhaust gases starts to provide enough
torque to the centrifugal compressor, thereby the availability of
oxygen becomes gradually sufficient. In fact, as time passes the CW
reaches the proper RpM and air is finally compressed inside the
intake manifold. To summarize, during acceleration the conventional
turbo compressors (centrifugal compressors in particular) are
unable to provide oxygen to the engine for a time period depending
on engine load and rate of acceleration. During this time a severe
production of particulate (especially when heavy fuels are
considered) is discharged into the environment. To eliminate, or
minimize, the turbo-lag phenomena, some engine manufacturers
utilize different mechanical compressors (i.e. positive
displacement compressors) which show a reasonable efficiency at low
RpM. These mechanical systems are coupled with the engine
crankshaft, thereby utilizing power from the engine to operate
(less efficient). When these devices are utilized the production of
pollution is reduced during acceleration, but unfortunately engine
performance is also penalized, especially at high engine RpM. The
only commercial alternative widely used (for example for large
diesel engines) is to utilize two different air-enhancing systems
in tandem. Therefore, a positive displacement air compressor,
utilizing power from the engine, and a centrifugal compressor are
coupled so that one provides oxygen at low RpM, while the other
pressurizes the intake manifold at higher RpM. This solution is
very expensive and results only in a modest improvement of the
overall engine efficiency. Another way to provide excess oxygen
inside the intake manifold at low engine RpM is represented by
electrical compressor. These compressors are generally
characterized by an electrical motor coupled with a centrifugal
compressor able to provide excess oxygen to the engine
independently of engine RpM. Generally, these electrical motors are
controlled by sophisticated and expensive electronic controllers,
and require extremely high current densities to provide the needed
torque in a few hundreds of milliseconds. In other words, these
compressors are capable of providing the needed oxygen at low
engine RpM, but unfortunately they require extremely high electric
consumption for their operation. The high current densities
required for the electrical air compressors also poses serious
problems by originating large emissions of electromagnetic
interference, and by generally overloading the conventional
electrical systems (i.e. alternator, batteries) aboard the
vehicles. Therefore, although the electric compressors satisfy the
requirement for oxygen at low engine RpM, they also require so much
power to run that the overall energy balance might actually show a
deterioration of the overall engine performance instead of the
opposite.
[0009] The main objective of the proposed invention is to provide a
waste energy recovery system capable of reducing environmental
pollution while increasing the engine performance. Therefore, this
invention converts heat into mechanical energy which can be used to
produce electricity, air pressure, or availability of thermodynamic
work.
SUMMARY OF THE INVENTION
[0010] One of the main objectives of the proposed invention is to
provide an anti-pollution device while increasing the power
system's overall performance without affecting the fuel specific
consumption. In general, this invention consists of a special
thermodynamic engine coupled with the power system, the waste
energy of which is the source of energy of the thermodynamic
engine. Because the converters and expanders utilized are extremely
compact, the overall MWHE can be easily assembled/integrated with a
conventional IC engine. Superheated vapor is generated by injecting
a relatively low-pressure fluid with the desired thermodynamic and
thermal physical properties (i.e. water or any proper fluid) inside
a special heat transfer converter which transfers the heat released
by the cooling system and exhaust gases of the engine to the fluid
instantaneously. In general, by considering a 50-60 horse-power
(HP) engine, about 20-24 kW (where 1 kW=1.341 HP) are normally lost
in the form of heat irreversibly discharged into the environment.
This heat is normally lost through the exhaust gases and forced
convection through the engine coolant system and radiator. The
minimum energy required to accumulate enough oxygen inside the
intake manifold when the engine is accelerating from idling to
higher speeds can be estimated between 0.8-1 kW for a small volume
engine, and about 3 kW for a medium large diesel-fueled engine.
Normally the efficiency of a standard centrifugal air compressor is
not greater than 60-70%, therefore the energy required at the
compressor shaft is about 3.2 kW. A device utilizing a 20 kW energy
source to convert it into 3.2 kW minimum energy required to provide
compressed air should have an efficiency of at least 16%. Such a
low efficiency is normally not even considered for power
generation; however, in this case the energy source is waste energy
and recuperating even a small fraction of it only represents a gain
for the overall engine efficiency. Therefore, the thermodynamic
cycle of the NWHE is a vapor cycle based on an injection of water
(or a proper fluid) into the heat transfer converter which
instantaneously flashes the water to superheated steam with no need
for steam boilers or accumulation (as is for conventional vapor
cycles). The pressure of the water injection and the mass flow rate
can be varied as a result of the quantity of heat available inside
the converter, or simply as a function of the amount of waste heat
that we want to recuperate. Once water is injected inside the
converter it expands instantaneously, changing its specific volume
and making the heat transfer process extremely rapid. The energy
collected by the superheated steam while transiting inside the
converter is then utilized inside one or more expanders able to
provide power directly to the crankshaft, and/or drive the
oxygenators. If the engine is a medium-large volume engine the
production of waste heat is greater than the heat necessary to only
drive the oxygenators. In this case, the excess superheated steam
energy can be utilized to drive an additional expander that returns
(directly or indirectly) mechanical energy to the engine
crankshaft. To summarize, the MWHE can be formed by one or more
heat converters, and at least two expanders. One expander is
coupled with the engine load through a special clutch, and the
other provides a constant optimum speed for a special
centrifugal-type compressor forming an air/oxygen enhancing system
(oxygenator) powered by waste energy. The superheated steam formed
inside the converter then expands in the expanders and condenses
inside a radiator, or as a result of steam collapsing when exposed
to the cold surfaces of chambers inside the expander (imploding
systems). Furthermore, the sudden implosion of vapor inside the
imploder chambers causes a drop in the system pressure (i.e. P=0.09
bar when T=45.degree. C.) which increases the efficiency of the
MWHE thermodynamic cycle. At this point the condensed fluid (back
in its liquid form) is pressurized back into the injector, and a
new cycle starts over. By rough estimates, it is possible to assume
that if the maximum temperature reached by the superheated steam
inside the converter is only 450.degree. C., the overall efficiency
of the waste heat thermodynamic cycle is approximately 21%. This
means that a vapor cycle with the above characteristics could
provide at least 3.4 kW shaft power to a compressor of whatever
type. In other words, the thermodynamic engine described in this
invention can be utilized to power an air/oxygen enhancing system
at no cost for the overall energy balance of the engine. If the
converter provides a superheating temperature greater than
450.degree. C., for example 600.degree. C., the overall efficiency
of the thermodynamic cycle would reach 29%. The maximum temperature
achievable by the superheated vapor inside the converter is
proportional to: the length of the converter; the distance between
heated surfaces inside the converter; the roughness of the
converter internal surfaces; mass flow rate of liquid fluid to be
converted into vapor; mass flow rate of exhaust gases transiting
inside the converter; thermal insulation between converter and
surrounding environment; and many other less crucial variables. In
general, exhaust gases temperatures can reach values higher than
600.degree. C., and the relative efficiency of the converter can be
much higher than 29%.
[0011] To summarize, the device of this invention recuperates a
fraction of the energy normally lost in the form of heat from
conventional power systems and combustion engines. By utilizing
this energy to drive oxygen enhancing systems, engine pollution can
be drastically reduced while engine performance is increased. By
utilizing this same energy to drive a work-producing unit, the
overall engine efficiency can be further improved since more power
can be provided to the engine load. Then the overall engine power
output is a result of the summation of the power normally provided
by the engine and the power recuperated from the waste heat.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a representation of a basic centrifugal air
compressor within which an additional work-producing unit is added
in the central body of the compressor, thereby forming an intake
air-enhancing system which utilizes the exhaust gases kinetic
energy in tandem with the expansion of superheated vapor inside an
expander coaxial with the CW.
[0013] FIG. 2 is a sectional view representing the mechanical parts
of the work-producing unit which can be assembled inside the body
of widely used centrifugal compressors. This work-producing unit
includes active means for the optimum regulation of the expander
speed along with an autonomous and innovative lubrication
system.
[0014] FIG. 3 is a sectional view of the central body of the
expander which utilizes an internal imploding chamber/surface able
to cause sudden vapor condensation.
[0015] FIGS. 3A and 3B are sectional views representing the central
body of the expander equipped with active servo mechanisms
controlling and regulating special vapor nozzles.
[0016] FIG. 4 is a schematic representing the hydraulic lubricating
system and the pumping effect caused by internal blades embedded
into the shaft.
[0017] FIG. 4A is a sectional view of the expander in which the
outlet nozzles are oriented in a configuration which offers a
counter balancing force for the thrust bearings.
[0018] FIG. 4B is a sectional view of the expander coupled with a
CW in an up-side-down configuration and equipped with a balancing
variable mass system.
[0019] FIG. 5 is a sectional view of a special expander whose wheel
contains multiple stage blades within the same circumference,
coupled with a centrifugal CW and an EGW showing also an external
jacket for the reutilization of the heat loss by the surfaces of
the EGW casing.
[0020] FIG. 6 is a sectional view of an expander similar to that
described in FIG. 5 except that the vapor circulates inside a
jacketed system surrounding the EGW casing independently of the
vapor circulating inside the expander.
[0021] FIG. 7 shows a detailed representation of the multiple stage
blades located on a single wheel, lighter, compact, and able to
provide the torque of three equivalent wheels operating with vapor
with different thermodynamic properties.
[0022] FIG. 8 is a sectional view of a special expander coupled
with a centrifugal CW positioned with 180.degree. rotation and
having a discharge section formed by a diverging conical nozzle
able to recuperate most of the kinetic energy of the air once
leaving the blade tips of the CW. In this Figure a series of intake
air by-pass valves are also shown.
[0023] FIG. 9 is a sectional view of a centrifugal compressor
coupled with a vapor expander completely symmetric for easiness of
manufacturing and assembly.
[0024] FIG. 10 is a sectional view of an expander forming a
work-producing unit coupled via reduction gears to a centrifugal,
mechanical, hydraulic, or electromagnetic clutch which transfers
mechanical energy to the engine load.
[0025] FIG. 11 represents the application of the
expander-compressor unit as an oxygen enhancing system connected
directly on the air filter barrel of the engine intake manifold
without affecting the operation of existing turbo compressors or
turbochargers already installed on the engine.
[0026] FIG. 12 represents the application of the
expander-compressor unit as an oxygen enhancing system positioned
inside the intake manifold utilizing a jet effect to pressurize the
intake manifold. Again, this application does not affect existing
turbo chargers or compressors already installed on the engine.
[0027] FIG. 13 shows the optimization of a conventional turbo
compressor. In this case, the expander-compressor air/oxygen intake
is independent and the pumping jet effect is optimized for higher
performance at low engine RpM.
[0028] FIG. 14 shows a series of different configurations of the
expander compressor unit by coupling the expander to existing
compressor parts, or by coupling the expander to specially
manufactured parts (i.e. special multiple stage blades wheel, or
symmetric parts).
[0029] FIG. 15 shows the hydraulic circuits of the various heat
converters located inside the muffler, inside or surrounding the
exhaust manifold, and the jacket surrounding the EGW casing. In
this Figure, the heat converter formed by a jacket in thermal
contact with the hot surfaces exposed to hot exhaust gases driving
the wheel, and thermally insulated from the surrounding
environment, forms a hydraulic path which allows superheated vapor
to flow directly into the expander (shown in detail in FIG. 5).
[0030] FIG. 15A shows a cooling system formed by heat fins/vents of
the converter positioned onto or inside the exhaust manifold able
to re-circulate cooling air in case of malfunctioning of the
converter or the MWHE.
[0031] FIG. 16 shows a hydraulic circuit similar to that shown in
FIG. 15. In this Figure the connection of the various converters
allows further superheating of the vapor and increases the overall
efficiency of the MWHE.
[0032] FIG. 17 is a schematic representing the thermodynamic cycle
made by the fluid (i.e. water or any proper fluid) from the
condenser to the converter(s), to the expander(s), and back to the
condenser.
[0033] FIG. 17A is a schematic representing the thermodynamic cycle
as shown in FIG. 17 with the addition of a high pressure insulated
accumulation tank in which excess waste heat can be accumulated to
pulse the expanders.
[0034] FIG. 18 represents a sectional view of a heat converter of
easy construction and equipped with internal fins/paths for a
better heat transfer, thermally insulted with proper materials or
by means of an additional jacket in which it is possible to obtain
a vacuum and good thermal insulation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] The working principles of the MWHE of the present invention
are now described by utilizing the schematics and representations
shown in FIGS. 1-18.
[0036] The thermodynamic steps of the MWHE's cycle are represented
in FIGS. 17, and 17A. Since the MWHE is formed by the combination
of several sub-components, each of them characterized by unique
features, the description of the MWHE should be somewhat simplified
by describing the sub-components first. The most important
sub-components of the MWHE cycle, expanders, converters, imploders,
oxygenators and their applications are described in FIGS. 1-16.
FIGS. 17 and 17A, and basically provide the overall hydraulic
connection and method of operation of each sub-component as part of
a single device: the MWHE as a plant. Therefore, the basic
components of a centrifugal compressor modified to integrate the
vapor expander block of the MWHE are shown in FIG. 1. The body of
the expander 1 is comprised inside the dashed block of FIG. 1. The
vapor expander 1 contains at least one bladed Expander Wheel "EW,"
6, with blades 6a designed to provide the proper torque at a
desired mass flow rate and thermodynamic properties of the vapor.
The material of the wheel itself can be metal, composite, or a
combination. In general, the material of the wheel has to have
enough strength to sustain the mechanical stress imparted by the
vapor, and it has to have good thermal stability at the operational
temperature imposed by the expanding vapor. The outermost edges of
the tips of blades 6a can be made of a sealing material (i.e.
Teflon), which becomes softer when its cross section is
sufficiently thin, offers good lubricating characteristics, and
forms a good seal between the rotating parts of the wheel and the
static casing 1. The shape, the height, and angles of the blades 6a
of the EW are designed such that the maximum torque is obtained at
a desired RpM, thereby matching the optimum RpM of the air CW 2a,
inside the diffuser 2. EW 6 is also co-axial with the EGW 3b, and
the CW 2a. All of the wheels 6, 2a, and 3b are mechanically coupled
to the same shaft 12 pressure-sealed in various points (not all
shown in FIG. 1) by a series of o-ring seals 93 or similar. Inside
the expander block 1, there is at least one thrust bearing(s) 4,
and/or fluid lubricated bearings 5 of conventional design, or of
special design as described in FIG. 4. To achieve a good thermal
insulation between the expander casing 1, and the air compressor
sections formed by the CW 2a, and casing 2, a thermal seal 18 is
positioned between the compressor parts and the expander body 1. In
this configuration the thermal insulation 18 is necessary to
prevent heat from the expander from being transferred to the
compressed air inside diffuser 2.
[0037] In FIG. 2, expander 1 is shown in detail. The superheated
vapor generated in the converters described in FIGS. 5, 6, 15, 16,
and 18 enters inlet 9 (FIG. 2) which can be positioned
symmetrically with respect to shaft 12 of FIG. 1, or they can be
positioned anywhere on the expander body 1. If water is the working
fluid of the MWHE (any fluid with the proper thermodynamic, and
physical properties could be utilized), superheated steam at a
desired pressure and temperature enters inlets 9 and flows through
nozzles 17. Nozzles 17 can be simple converging static nozzles,
designed to obtain a desired pressure-to-velocity conversion, or
they can be actively actuated or statically tuned through means 15,
14, and 13. These means allow the pressure and velocity of the
steam to be finely adjusted before it expands through blades 6a of
EW 6. Regulation means 14 consists of a mechanical link able to
insert or withdraw a special needle 13. In this manner the expander
can be customized to operate at an optimum speed as a function of
the mass flow rate and thermodynamic properties of steam entering
through inlets 9. Nozzles 17 are positioned inside the body of the
expander 1 in a way that the forces generated against blades 6a
counterbalance the forces acting on the shaft 12 (FIG. 1). This
reaction force is proportional to the mass of steam impinging on
the blades 6a. Once steam expanded though EW 6 it can exit expander
1 though the discharge paths 10 which are hydraulically connected
to a condenser/radiator 86 shown in FIGS. 17, and 17A. Lubrication
of bearings 5 is accomplished through an oil tank 16, oil paths
16a, and 16b, and a sump tank 16c. The lubrication methods can
utilize conventional designs via forced circulation of oil through
an external pump, or through an innovative method shown in FIG. 4.
Expander 1 can also be designed such that bearings 5, and the
hydraulic oil paths 16a, and 16b, are not integrated inside the
expander body (for example, bearings 5 could be positioned inside
blocks 2 and 3 of FIG. 1). To minimize heat and pressure losses
between the EW 6 and the static block of expander 1, a series of
proper seals (o-ring, graphite, etc.) can be positioned as
indicated by number 93. As an additional sealing mean between the
blades 6a and the static components of expander 1, a Teflon coating
of the volume surrounding the wheel and on the EW 6 itself can be
utilized. For example, if the wheel is made of Teflon, the tip of
the blades can be molded (or machined) such that the flexibility of
Teflon is utilized as a centrifugal seal. Then, a flexible portion
of the blades, at the edge of the blade's tip, rubs against the
casing containing the wheel. Since the casing is Teflon coated from
the inside (or a Teflon ring is positioned around the wheel) the
overall structure becomes sealed although the wheel is rotating and
the case is static. Furthermore, the optimum lubricating
characteristics of Teflon allow the seal to last a significant
amount of time; however, any other sealing compound could achieve
the same results. To minimize heat transfer from the expander body
to the compressor body a thermal seal 18 is utilized as shown in
FIG. 2. The material of this seal has very low thermal
conductivity.
[0038] In FIG. 3, the transfer of heat between the expander body I
and the compressor body is instead favored. In this configuration
steam exits the blades 6a and enters a condensation chamber formed
by a hydraulic path defined by fins 19 and 20. In this manner,
relatively cold air passing through the compressor cools down the
surfaces of the condensation chamber and vapor implodes
instantaneously. When steam suddenly condenses (implodes),
immediately after its expansion through the blades of EW 6, it
causes a steep pressure drop which increases the overall expander
efficiency. The choice between an expander 1c of FIG. 3, or 1 of
FIG. 1 is mainly based on a compromise between the desired air
compressor efficiency and the efficiency generated by the
combination of the various waste heat converters. In FIG. 3, steam
enters the expander 1c from inlets 9 (here shown in a non-limiting
symmetric configuration) passing through nozzles 17 where its
thermodynamic characteristics in terms of pressure and velocity are
adjusted actively or statically. Then, it expands through blades 6a
and enters a forced cooling hydraulic path formed by fins 20 and
20a. Fins 20a have the purpose of extending the cooling surface
area formed by fins 20a of component 19 in contact with large mass
flow of the compressor intake air. As soon as steam enters in
intimate contact with the surfaces 19, cooled by air, steam
contracts suddenly changing its specific volume of a factor greater
than a thousand. This sudden change in specific volume inside a
system where the system volume is fixed provokes a steep drop in
the local pressure. Decreasing the pressure at the discharge of
blades 6a is equivalent to increasing the pressure at the exit of
nozzle 17, thereby obtaining more thermodynamic work at the shaft
of the expander (i.e. 12 in FIG. 1). Since the air flowing on the
outside of the expander could be the same air/oxygen being
compressed inside the engine intake manifolds, the temperature of
the compressed air increases consequentially. However, since the
mass of steam to be condensed is minimum with respect to the mass
of air flowing inside the compressor side, the increase of air
temperature is minimum, thereby affecting the air compressor
efficiency only marginally. In other words, the pressure drop
caused by the forced steam implosion causes an increased expander
efficiency, while the consequential air temperature increase causes
a lower compressor efficiency. However, the overall device
efficiency increases since the gain in expander efficiency is
greater than the loss of the compressor efficiency. In FIG. 3A, and
3B the expander bodies 1c and 1 of FIG. 3 and FIG. 2 are shown side
by side to show their major differences. In FIG. 3A, and 3B, the
control of the EW 6 velocity is executed in a dynamic manner
(active control), through means 13 able to adjust the diameter of
nozzle 17 and control the thermodynamic properties of steam flowing
through nozzle 17 via computer/controller 92, described in FIG. 17,
or through a specialized sub-computer system, indicated by "S".
Sub-computer system S, is a specialized controller which optimizes
the operation of a particular sub-component of the miniaturized
engine (in this case the expander). Sub-computer system S can be
interfaced with the computer 92 described in FIGS. 17 and 17A.
Needles 13 are continuously re-positioned/adjusted through the
servo mechanisms driven by motors 112. Motors 112 can be driven by
electricity or be activated by pneumatic means. The basic control
of EW 6 speed is executed via detection of the wheel speed through
a movement sensor 115 (i.e. Hall effect sensor) connected to the
computer 92 of FIG. 17. Computer 92 monitors the whole
thermodynamic condition of the expander and heat converter(s) and
adjusts the position of needles 13 proportionally to the amount of
steam available, its thermodynamic state, the speed of the wheel
and so forth. In this manner, EW 6 is always operated under optimum
conditions.
[0039] In FIG. 4 a preferential hydraulic circuit for the
lubrication of shaft 12 is shown. In FIG. 4, bearings 5 are
represented in a non-limiting manner inside the body of the
expander. Bearings 5 can be formed by bushing materials lubricated
by the rotating action of shaft 12. Oil 24, or a lubricating fluid,
inside tank 16 flows inside the hydraulic paths 16a and 16b forming
inner channels and undergoes an acceleration through embedded
blades 22 etched on the surface of shaft 12. In this manner, oil 24
gains kinetic energy inside blades 22 and converts this energy into
potential energy. For example, oil molecules 24 (FIG. 4 top right),
enter channel 16a and flows inside the internal blades 22 on shaft
12. Blades 22 are shaped in a way that the rotation of the shaft
imparts acceleration to the oil as soon as the shaft reaches
minimum speeds. In this manner the velocity at the end of channel
16b is higher than that at the entrance of channel 16a generating a
pumping effect. Since shaft 12 rotates at reasonably elevated RpM,
even a slight angle of blades 22 causes a desired pumping effect.
Therefore, oil 24 inside tank 16 is forced by a depression in
channel 16a to go through blades 22, lubricating the bushing or
bearing 5 and returning back to tank 16 through channel 16b. In
other words, lubrication of shaft 12, bearing or bushing 5 occurs
as an automatic result of the rotation of shaft 12. The higher the
number of revolutions per minute of shaft 12, the more oil is
pumped through blades 22, therefore lubrication and cooling effects
increase with increased shaft rotational speeds automatically. In
general, blades 22 can be formed by micro-channels properly shaped
on the surface of shaft 12 or 12b. The number of blades 22 can be
even or odd as long as symmetry and/or balancing of shaft 12 or 12b
is respected. The oil paths from tank 16 to the various bearings 5
can be made such that each bearing has its own oil inlet and
outlet. Oil inlet 16a could be located at the inlet of one set of
bearings 5 (FIG. 4, bottom), be accelerated by a first set of inner
blades 22, flowing inside shaft 12b through hole 23a into channel
23 inside the shaft, entering the suction side of inner blade 22,
through hole 23b, and finally being discharged into channel 16b
which returns the oil back to tank 16.
[0040] In FIG. 4A, the effect of the forces developed by the action
of the EGW 3b, CW 2a, and EW 6 is represented. A solution to the
wearing of the thrust bearing is now described. Thrust bearing 4,
which can be positioned anywhere along shaft 12, normally has to
counterbalance the reaction forces developed by the EGW 3b and the
CW 2a. These forces are developed as a reaction to the motion of
the exhaust gases and air on the blades of the wheels. When EW 6 of
the vapor expander is integrated inside the body of the overall
device (for example as shown in FIG. 1), it is possible to position
nozzles 17 such that the reaction forces developed by the steam on
the blades of EW 6 counter oppose the effect of the forces
generated by all other wheels (i.e. 3b and 2a, FIG. 4A), thereby
minimizing the wearing effect on the thrust bearing 4. By
positioning and properly dimensioning nozzles 17, the net vapor
force 118, indicated by F.sub.vapor, could be of the same magnitude
and opposite direction of forces 116 and 117 generated by wheels 2a
and 3b and indicated on the vector diagram (FIG. 4A, top) as
F.sub.air and F.sub.gas. In fact, by assigning a positive sign to
the forces from left to right, F.sub.vapor is positive, while
F.sub.air and F.sub.gas are negative (the vector notation is not
necessary since they all move about the same axis). By properly
dimensioning the diameter of nozzles 17, along with the proper
dimensioning of the waste heat converters, and the diameter of EW
6, it is possible to generate a reaction force 118 resulting from
the momentum generated by the expanding steam. In FIG. 4A, the
direction of the forces represented is only indicative. If the
expander is utilized only as an independent oxygenator (i.e. FIG.
8), EW 6 operates at constant RpM, (particularly the case for
applications described in FIGS. 11, 12, and 13), therefore, it is
possible to adjust the reaction force of the vapor (F.sub.vapor) in
a way that the axial forces acting on the thrust bearing are
zeroed.
[0041] In FIG. 4B the expander is coupled with a flipped CW 2a
(details of this configuration are described in FIGS. 8 and 9), and
it is equipped with a balancing system which acts on the rotating
masses and adds its own weight as a, force opposite to the reaction
force 116 of the CW 2a. Even in this case the proper dimensioning
of the EW 6, along with the proper overall MWHE thermal properties,
and the correct positioning of nozzles 17 inside the expander body
can minimize the effects of the reaction forces caused by CW 2a and
acting on thrust bearing 4. In this configuration the CW 2a is
positioned in a way that it forms 180.degree. from the position of
the same wheel utilized in conventional centrifugal compressors. In
this case, the axial component of the forces acting on thrust
bearing 4 is mainly made by force 116 generated by the centrifugal
compressor itself (pushing shaft 12 upward). If the body of the
oxygenator (30, in FIG. 8) is positioned vertically, then nozzles
17 in FIG. 4B can be positioned such that the summation of the
forces generated by the weight of shaft 12 (times the force of
gravity, "FG"), the weight of the balancing mass 120 and 121 (times
FG), generating force 119, and the resulting force 118 caused by
the steam reaction on the blades of EW 6 could be exactly equal and
opposite to force 116, thereby zeroing its effect. Similarly, if we
significantly increase mass 120, or we utilize a heavy CW 2a (i.e.
obtaining a flywheel effect), nozzles 17 can be positioned in a way
to favor the effect of force 116. Balancing mass 120 and 121 also
provides means to adjust the usual off-balance components of shaft
12, coupled with the various wheels. In fact, mass 121 can be moved
from its central position through screws 122 and blocked in place
by screw 123. The mass system formed by masses 120, 122, and 123
can be positioned anywhere along shaft 12 (the dimensions
represented in FIG. 4B are not scaled). In this manner the
balancing of the whole rotating system (i.e. shaft 12, CW 2a, EW 6,
and eventually EGW 3b) can be executed once the unit is
assembled.
[0042] An integrated vapor expander 1a positioned inside the
components of a conventional turbo-compressor is shown in FIG. 5.
In this Figure, expander 1a is formed by a special Multiple Stage
Wheel, "MSW," 7, characterized by a series of blades 7a, 7b, and
7c, assembled molded, or machined inside the same wheel. Steam
enters expander 1a through inlet (or inlets) 9d positioned on the
body of a special jacket 25 containing the bodies of the
centrifugal exhaust gas nozzle 3a and the EGW 3b. Steam is provided
at the desired temperature, pressure, and mass flow rate by the
converters described in FIGS. 15, 16, 17, and 18. Again, steam
enters at inlets 9d, receives additional heat mainly by convection
and radiation inside the heat chambers formed by the surfaces of
nozzle 3a and jacket 25, and plows inside the expander body 1a. To
minimize heat losses, insulating materials can be utilized, or a
vacuum chamber can be formed by evacuating the air inside another
chamber formed by the surfaces of jacket 25 and those of an
additional jacket 25a. Air can be extracted during manufacturing,
or through a vacuum valve 124. Superheated steam now enters the
expander body 1a and expands through the first set of converging
nozzles 17 (the drawing is symmetric). The exit diameter of nozzle
17 is designed to transfer the maximum momentum to the first set of
blades 7a of MSW 7. Again nozzles 17 can be fixed or actively
adjusted as shown in FIGS. 2 and 3. Normally, steam exiting this
first stage of blades (7a) would enter a new stage of blades on a
new separated wheel designed to match the new steam properties. In
this invention a new series of blades 7b is still positioned on the
same wheel (MSW 7), but has a different diameter and a different
shape to compensate for the changed steam direction and its varied
thermodynamic state. Therefore, steam loses a fraction of its
energy by expanding through blades 7a, it then enters a new set of
nozzles 17a (fixed or actively adjusted) after having changed
direction by 180.degree. through a polished elbow inside the body
of expander 1a. Now, steam at certain thermodynamic conditions
expands through the new set of blades 7b. Another converging nozzle
17b provides the proper adjustments in terms of steam pressure and
velocity, since steam loses more and more energy as it expands in
the various stages. Exiting nozzle 17b, steam expands again inside
another set of blades 7c positioned on the periphery of MSW 7.
Finally, the exhausting steam is removed from expander 1a through
the discharge hydraulic paths 10, or through an imploding chamber
(not shown) as described in FIG. 3. Therefore, the technique of
turning the steam flow path of 180.degree. allows the generation of
more torque from the same wheel instead of three or more, thereby
reducing weight, inertia, and allowing a significant
miniaturization of the expander body. The lubrication system of
expander 1a can be formed by a conventional oil lubricating system,
through an external pump, or by a system that utilizes bearings 5
as described in FIG. 4. If the lubrication system is similar to
that described in FIG. 4, the oil, or an equivalent lubricating
fluid, can be cooled through tanks 16c, assembled on the diffuser
body of the air compressor. Since the maximum temperature of the
air at the discharge of the CW 2a is only 1.5 to 2.5 times the air
inlet temperature (generally below 40.degree. C.), this section of
the overall device can provide proper cooling for the lubricating
fluid. To minimize heat losses from the expander body 1a to the air
flowing inside the compressor, a thermally insulating seal 18 is
positioned as a buffer between the two different bodies.
[0043] FIG. 6 represents an expander integrated inside the body of
a turbo-compressor with characteristics similar to those described
in FIG. 5. In this Figure the steam flowing inside the heat chamber
formed by surfaces 3a and 26e occurs in a way that it can flow in
and out the heat chamber independently of inlets 9e of the expander
body 1a. The heat chamber is also thermally insulated by vacuum
through valve 124, or by utilizing thermally insulating materials
coating, or covering the external surfaces 26e (i.e. thermal
blanket 25b). In this configuration, steam is superheated to
certain temperatures, and then can be forced inside another heat
converter to reach even higher superheating temperatures.
[0044] FIG. 7 represents MSW 7 with more details. To conserve the
desired direction of rotation indicated by 27, the
inclination/shape of blades 7a, 7b, and 7c changes in each stage.
As shown in FIG. 5 and 6, steam enters inlets 9, accelerates inside
nozzle 17 and expands in the first series of blades 7a whose shape
is designed to transfer the kinetic energy of the steam into
mechanical energy at the shaft of the wheel. The shape of blades
7c, 7b, and 7a, represented in the drawings of FIG. 7 is only
indicative. Now, steam exhausting blades 7a is redirected and
enters a new nozzle 17a to expand through blades 7b. The
inclination of blades 7b is different than that of blades 7a so
that the rotational direction 27 is conserved. Finally, steam
exhausting from blades 7b is redirected again and conditioned by
nozzle 17b designed to convert low pressure steam into kinetic
energy, and expands through blades 7c. At this point, the steam
energy content is low and it can be discharged into condenser 86
(FIG. 17 or 17A). Each series of blades 7c, 7b, and 7a is connected
to the MSW 7 through sections 26 and 26a. The number of sections 26
and 26a can vary proportionally to the diameter of the wheel, the
mass flow rate of steam, and the torque required.
[0045] An innovative centrifugal compressor
(oxygenator)--completely symmetrical, easy to manufacture and
utilizing simpler parts--is shown in FIG. 8. Again, the oxygenator
is one of several sub-component of the MWHE. In this case, expander
1a is mechanically connected to a CW 2a assembled 180.degree.
rotated with respect to shaft 12. This configuration allows
symmetry of the mechanical parts (easier to assemble and
manufacture) and provides higher compressor efficiencies. Air flows
through air path 40 and through an axial diffuser 29, entering the
body of CW 2a and gaining kinetic energy as a result of the
centrifugal action of the wheel. Air exits with the maximum energy
at the tip of CW 2a's blades, and enters a diffuser specially
shaped as indicated by region 95 in FIG. 8. This diffuser is
symmetric and divergent along the whole length of body 30. The
first transformation of the kinetic energy of the air into pressure
occurs in region 95, and further gain in pressure occurs along
fixed blades/vanes 31 regularly spaced on a fixed cone 33. The
shape of vanes 31 is such that the turbulent motions and vortexes
of the air at the exit of CW 2a (blades tip) are reorganized,
redirected and converted into pressure (useful energy).
Furthermore, the cross section of the diffuser formed by cone 33
and the internal surfaces of body 30 makes a diverging nozzle. In
fact, the cross section radially changes from small to large, as
shown by distances d1 and d2, indicated by number 32. In this
manner another component of the velocity of the air exiting the CW
2a is converted into pressure. Body 30 is mechanically linked to
the expander 1a through coupling flange 28. Cone 33 and vanes 31
are static and fixed to body 30. To summarize, the body of the
oxygenator is formed by two concentric cones having different
height and diameter, or by a cone concentric and internally
positioned inside a cylinder able to provide characteristics
similar to those described by body 30. Flange 28 can be linked with
body 30 through additional static fins/vanes (directing the air
flow into CW 2a), or through an open semi-toroid body 39
surrounding the inlet of the oxygenator and providing the structure
for the intake manifold 40. Manifold 40 can be easily connected to
a conventional air filter. The overall device formed by the
expander 1a and body 30 forms an oxygenator which can be designed
to provide a minimum mass flow of oxygen sufficient to allow
complete combustion from idling IC engine RpM to medium high RpM.
If the outlet of the oxygenator 40a is connected to an engine
intake air system equipped with a conventional turbo-compressor,
membrane valves 38 could automatically open every time the pressure
in the region adjacent the vortex of cone 33 is below atmospheric
pressure. Therefore, the oxygenator could be designed to provide
oxygen at low RpM, while the conventional turbo-compressor would
start to operate properly at high RpM, so that the by-pass valves
38 allow the turbo-compressor to breathe even if the oxygenator is
not dimensioned to provide the full range of mass of air at high
engine RpM. By-pass valves 38 are formed by membrane 35 composed by
flexible materials (i.e. rubber, composite) with the proper
thickness, dimensions, torsion and physical properties. One by-pass
valve 38 with the proper hydraulic diameter (effective cross
section seen by the fluid), or more valves with equivalent air flow
characteristics can be assembled on body 30. In general, expander
1a, 1 (or 1b as described in FIG. 14), can provide the propulsion
necessary to CW 2a. If the expander is properly miniaturized it can
also be inserted inside the body of cone 33, as indicated by dashed
box 1c. In this case, steam inlet paths 9, and steam discharge
paths 10 can be made through the thickness of vanes 31. Steam paths
9 embedded inside fins 31 would be thermally insulated, while the
steam exhausting from EW 6, or MSW 7, would be exposed to the
air-cooled surfaces of cone 33 and vanes 31. When the steam
exhausting EW 6 or MSW 7 impacts the cold internal surfaces of cone
33 it suddenly condenses (implodes), generating a pressure drop
which increases the overall oxygenator efficiency. This oxygenator
can also be coupled with a conventional EGW 3b (and relative
nozzle) by unplugging thermal plug 41 and extending shaft 12. In
other words, by prolonging shaft 12 it is possible to add pulsed
propulsion to the CW 2a by utilizing the kinetic energy of the
exhaust gases. Expander 1a shown in FIG. 8 (or even expanders 1, or
1b) can actually be miniaturized to a point that it can be inserted
inside the cone structure of the symmetrical oxygenator. In this
case, the oxygenator body 30 would contain cone 33 and inside cone
33 the expander 1, 1a, or 1b. Then vanes 31 would contain hydraulic
paths for the inlets 9 of expander 1a, and hydraulic paths for the
vapor discharge 10. The inlet hydraulic paths 9, now embedded
inside vanes 31, would be thermally insulated, while the discharge
paths 10 are allowed to transfer heat and condense inside the
hydraulic paths 10 (embedded inside vanes 31), since vanes 31 are
always at low temperatures due to the action of the mass flow of
air. By creating an implosion chamber inside cone 33, the surfaces
of the cone provide the cooling surfaces for superheated vapor to
suddenly collapse when in contact with the inner surfaces of cone
33. In this case, the symmetric oxygenator becomes extremely
compact since its expander and implosion systems are all contained
inside body 30. Furthermore, when a complete implosion occurs
inside body 30 there is no need to circulate the vapor inside a
condensing radiator (i.e. 86 in FIGS. 17, and 17A), thereby further
simplifying the miniaturized engine hydraulic path and
connections.
[0046] Another symmetric oxygenator, similar to that described in
FIG. 8, is represented in FIG. 9. In this oxygenator, air enters
the body of CW 2a, passing diffuser 29, in a radial manner (from
every direction). In this configuration a cylindrical air filter
can be positioned between body 30 and flange 28a. To improve the
efficiency of the CW 2a, static vanes can also be positioned inside
the intake path 96. However, the oxygenator can also provide oxygen
to the engine without an air filter assembled on itself (see FIG.
11). In general, EW 6, MSW 7, and CW 2a, can be made of plastic,
Teflon, composite, metal or any material which maintains its
thermal-physical properties for relatively low temperatures (much
lower than the exhaust gases temperatures). If the MWHE is applied
to a large IC engine, the amount of heat generated by the engine,
recuperated by the converters, and transformed back into useful
energy by the MWHE's expanders is much greater than the energy
required only to power the oxygenators. Thus, the excess energy can
be utilized in various ways. For example, it can be utilized to
provide additional mechanical power to the IC engine itself.
[0047] In FIG. 10, an auxiliary pulsed or continuous power
transferring system formed by the Auxiliary Expander Flywheel AEF
11 is shown. In this figure, the power unit comprised by body 42 is
directly connected to the IC engine block 43. In general, power
unit 42 can be connected to any load (i.e. an alternator for the
production of electric power). In FIG. 10, the excess steam enters
hydraulic paths 9c, and expands through the blades of AEF 11. AEF
11 is made of heavy materials to provide a large rotational
inertia. Steam enters nozzles 17c and discharges into condensation
chamber 51. A fraction of the steam condenses in this chamber; the
remaining steam (steam with a low energy content) exits the power
unit 42 through paths 10b and condenses in a condenser. By cooling
chambers 51, the steam implosion effect described in FIG. 3 can be
utilized to increase the efficiency of AEF 11. A speed reduction
system formed by gears 49 and 50 may be necessary if the optimum
efficiency of the AEF 11 is obtained at high RpM. The optimum
parameters are mainly dictated by the amount of excess steam
available and the gear reduction system might not be necessary if
AEF 11 operates at RpM compatible with the IC engine RpM. AEF 11 is
mechanically coupled to the IC engine crankshaft 44 by a modified
pulley 45. The modification consists of a flange 46 mechanically
linked to another flange 47 coupled to a clutch system 48. Clutch
48 can be hydraulic, magnetic, friction based, or a combination of
any of these depending on the desired degree of accuracy when
transferring power from the power unit 42 to the IC engine (or any
load). For example, clutch 48 can be formed by oil whose viscosity
at a given RpM provides the desired frictional torque. If an
electronic clutch is utilized, sensor 55 monitors the speed of
crankshaft 44, while sensor 56 provides analog or digital
information on the speed of AEF 11. The electronic signals from
these sensors become inputs (i.e. 135 FIG. 17, and 17A) of a
computerized control system (92 FIG. 17 and 17A) which activates
clutch 48 in a pulsed or continuous manner. In order for AEF 11 to
provide power with the best efficiency, only a relatively small
fluctuation of the AEF RpM should be allowed. Therefore, by
utilizing the power provided by power unit 42 in a pulsed manner,
the RpM of AEF 11 could vary only slightly. To minimize heat losses
from the power unit 42, a thermally insulating material 54 covers
the static parts of AEF 11.
[0048] FIG. 11 represents one of the simplest applications of the
oxygenator unit 30. In this Figure, the outlet of the symmetric
oxygenator 30 is connected to the air filter inlet 60 positioned on
the body surrounding air filter 59. Large IC engines normally have
the air filter inlet formed by a tube vented to atmospheric
pressure. The expander of this oxygenator could be of type 1a, 1 or
1b. The oxygenator shown in FIG. 11 utilizes expander type 1a. By
applying the oxygenator as shown in this Figure, the whole engine
air intake system is always pressurized without altering in any way
the conventional turbo compressor 2 and 3 already installed. Air
enters the protective filter 57 from all directions. Then it is
compressed inside the air filter 59 which pressurizes the intake
manifold 61 and 63 regardless of the IC engine RpM, or the status
of compressor 2. When the IC engine accelerates, the sudden
increase of fuel injected mixes with excess oxygen (thanks to
oxygenator 30), providing a complete combustion and an extremely
rapid response without producing toxic particulate and other
pollutants during acceleration. If expander 30 is intentionally
under-designed (not able to provide large mass flow rates once the
IC engine reaches high RpM), the conventional compressor 2
gradually starts to compress air on its own (the IC engine is
accelerating from idling to high RpM), thereby provoking a
depression inside manifold 62, 61 and 60. As soon as the pressure
inside manifold 60 is below atmospheric, by-pass valves 38 open,
providing an easier path for air to flow inside compressor 2 now at
full regime. Steam inlet 9b and outlet 10 are connected to a
converter and a condenser, respectively (as seen in schematic in
FIGS. 17 and 17A). Since the expander unit 30 could accommodate for
an additional EGW connected to its shaft, a plug 41 is inserted
whenever this option is not utilized. If the oxygenator unit 30
breaks down, the IC engine operates as it did before the oxygenator
was installed, thereby without impairing the IC engine (it would
just decrease its performance and pollute again).
[0049] FIGS. 12 and 13 show the oxygenator unit 30 inserted inside
the intake manifold circuit. In these configurations, the
compressed air exiting the accelerating nozzle 64 or 66 is air
filtered by filters 59, or 59a. Pressure inside the intake manifold
is increased thanks to the jet effect caused by nozzle 64 or 66.
Again, thanks to the oxygenator, powered by MWHE, oxygen is always
available to the IC engine regardless of its RpM. Again, if the
oxygenator is intentionally under-designed, the proper mass flow
rate to the suction of compressor 2 is provided by by-pass valves
38. When the oxygenator is configured as shown in FIG. 13, nozzle
66 provides a more efficient output of oxygen to the intake
manifold 67. To make the oxygenator air inlet completely
independent from the IC engine air filter 59, an additional and
independent air filter 59a can be connected to oxygenator 30
through a sealed connection to inlet 40.
[0050] To summarize the various expander-to-compressor
configurations, a series of oxygenator units are shown in FIG. 14.
From left top, expander 1a shows the ease with which the expander
body 1a can be coupled with bodies 2 and 3 of conventional CW 2a
and EGW 3b. In particular, the expander wheel can be conventional
(i.e. EW 6) or the MSW 7 described in FIG. 7. For example, expander
body 1 of the oxygenator unit represented at the top center of FIG.
14 utilizes EW 6, while expander 1b utilizes a series of expander
wheels 8 for a conventional multiple stage steam expansion. In any
case, all of these expander units can be mechanically integrated
between the compressor and exhaust gas units normally available.
The miniaturization of the expander body 1a, 1 and 1b allows also
coupling with a convention compressor unit 2 and 2a so that oxygen
can always be provided to the IC engine independently of IC engine
RpM. For example, the oxygenator unit shown at the left bottom of
FIG. 14 describes an expander unit 1a able to provide steam
propulsion to a commercial CW 2a, while the shaft of the unit is
truncated on one side allowing the insertion of plug 41. This
particular configuration can be utilized for the applications
described in FIGS. 11, 12 and 13. The oxygenator represented at the
bottom center of FIG. 14 is the most optimized oxygenator unit
since it utilizes symmetric geometry and completely converts
vortexes and kinetic energy of the air into pressure. This unit is
formed by combining body 30 and 1a, or body 30 and 1, or body 30
and 1b. In general, a symmetric geometry can be conserved even if
the various expander bodies are embedded/integrated inside the cone
contained inside body 30. Finally, the oxygenator shown at the
bottom right of FIG. 14 is another oxygenator configured in a way
that air enters through an inlet manifold 40 and can flow through a
by-pass path 37c, and by-pass valves 38. This configuration is
particularly useful when the IC engine is already equipped with a
turbo-compressor, or turbo-charger, and the oxygenator only needs
to provide oxygen at idling and low IC engine RpM, while the
turbo-compressor already installed provides compressed air at high
RpM. All of the oxygenator bodies are designed in an universal
manner so as to allow for connections of additional EGW 3b, and
casing 3, by removing plug 41 and inserting a proportionally
dimensioned shaft.
[0051] The heat converters of the MWHE are shown in FIGS. 15, and
15A. Liquid water (or the proper thermodynamic fluid) is injected
at about 70-80.degree. C. through a pump (pump 87 shown in FIGS.
17, and 17A). Then, high pressure fluid is injected via injector 69
connected to hydraulic path 68. This injector can essentially be a
check valve, spring loaded, or electronically activated. If the
pump is a positive displacement pump, injector 69 can actually be
eliminated. Liquid fluid is now injected inside the heat converter
formed by body 70 within which hot exhaust gases 80 flow and are
vented to atmospheric pressure. The amount of energy transferred
from gases 80 to the fluid inside the converter depends mainly on
the fluid-converter contact surface, length d3, and mass of MWHE
fluid injected. To favor a greater heat exchange between fluid and
gases inside converter 70 a series of helicoidal surfaces 71 are
inserted inside the converter. These surfaces prolong the fluid
residence time inside the converter by extending the hydraulic path
of the fluid before it exits outlet 72. The working fluid (i.e.
water) expands inside the converter, accelerates by moving through
the helicoidal surfaces 71, and becomes superheated vapor or
superheated steam. Because of the explosive nature of the expansion
of the fluid inside the converter, the relative heat transfer
coefficient increases accordingly, thereby allowing a
miniaturization of the converter itself. Thus, superheated steam,
at certain thermodynamic conditions, is now available at outlet 72
(FIG. 15). Further superheating of steam can be achieved by
connecting outlet 72 to a series of superheating channels 73 in
thermal contact with the exhaust gases. The maximum superheating
temperature of the steam is reached inside channels 73 closer to
the combustion chambers outlet (near the exhaust manifold flanges
74). Channels 73 can be substituted by a jacket surrounding the
exhaust manifold becoming another converter. To regulate the excess
steam a three-way valve 77 is connected to tube 76 exiting the
converter formed by channels 73. In general, valve 77 can be
substituted by equivalent valves 77a, and 77b as shown in FIG. 17.
In FIG. 15 the oxygenator unit is integrated with a turbo
compressor as described in FIGS. 5 and 6, and is thermally
insulated by insulating material 25a. Valve 77 is operated to
control the admission of steam inside the expander unit, and to
redirect the excess steam to the AEF 11 (FIG. 10) through the
hydraulic path 79. Outlet 78 of valve 77 is connected to the
expander inlet ports 9d (or 9d, FIG. 5, and inlet/outlet ports 9d,
FIG. 6). Superheated steam expands inside the integrated expander
(1a, 1, or 1b), and condenses into a condenser through discharge
hydraulic path 10, or it condenses through implosion inside the
body of the expander (FIG. 3). To minimize heat loss from the
exhaust manifold 74, an insulating material 75 can be utilized as
shown in FIG. 15. Seals 94 between IC engine block and exhaust
manifolds 74 are made of a thermally insulating material as well
(conserving heat of the exhaust gases). To prevent overheating of
the converter formed by channels 73 in thermal contact with the
exhaust gases near the combustion chambers outlet, the thermally
insulating structure 75 can be arranged in a way that movable fins
134 (FIG. 15A) opens when the MWHE is malfunctioning. Therefore,
activating fins 134 in FIG. 15A provides cooling of the exhaust gas
manifold structure when steam is not circulating inside the MWHE.
In FIG. 15A, the thermal insulation 75 described in FIG. 15 can be
formed by an air chamber relatively sealed when fins 134 are closed
(when the MWHE is working properly), or thermal insulation is
minimized when fins 134 are automatically or manually opened (air
can circulate through the exhaust manifold). For example, opening
of fins 134 can occur if the temperature of the manifold materials
overcomes a pre-set safety threshold.
[0052] In FIG. 16 a higher degree of steam superheating can be
achieved thanks to different hydraulic connections of the various
converters. Again, liquid fluid is injected through injector 69,
becomes superheated at the max temperature of converter 70, exits
from outlet 72 and enters the converter formed by the jacket
surrounding the EGW 3b through inlet 9d. Here another energy
transfer process occurs and the superheated level is increased.
Superheated vapor exits this converter from outlet 9d and enters
the converter formed by channels 73. Here the level of superheat is
increased even further. Now, vapor at its maximum temperature and
pressure is regulated by valve 77. The excess vapor is directed
toward the AEF 11 via thermally insulated tube 79, while the proper
amount of superheated vapor is allowed to expand inside the
expander through thermally insulated tube 78, connected to expander
inlet 9e. Vapor gives up energy through the expander and condenses
into a condenser via tube 10. The exhaust gases 80, generated
during combustion, transfer heat to the various converters
(channels 73, jacket surrounding EGW 3b, and converter 70) while
also transferring their kinetic and pressure energy to EGW 3b
(blanketed by insulation 25b in FIG. 16). Oxygen, on the other
hand, enters the air intake manifold 81 and is compressed by CW 2a,
surrounded by structure 2. CW 2 in this configuration is powered by
the summation of the torque developed by the MWHE's expander
(especially at low IC engine RpM), and the torque generated by the
EGW 3b, once the IC engine reaches relatively high RpM. The various
converters utilized in FIG. 15 and 16 can be utilized in the
applications described in FIGS. 11, 12, 13 and 14.
[0053] Finally, thermodynamic processes of the complete MWHE are
described in the schematic in FIG. 17. The cooling circuit of the
IC engine 43 is formed by the closed hydraulic loop composed of the
water pump 82, radiator 84, and converter 83. The cooling water of
IC engine 43 normally reaches 90.degree. C., after which a
thermostat valve, usually positioned at the discharge of pump 82,
opens and allows a forced circulation of the coolant to the
radiator 84 which transfers heat via air convection indicated by
arrow 85. By inserting the heat converter 83 and 83a, most of the
heat carried by the coolant can be transferred to a new closed
hydraulic closed loop. Converter 83 and 83a separates the IC engine
cooling circuit from the MWHE circuit for safety and reliability.
However, this converter can be eliminated if the MWHE working fluid
is also utilized to cool the IC engine 43. In this case, radiator
84 becomes the condenser 85 of the MWHE, thereby simplifying the
overall device. If the hydraulic circuit of the MWHE is independent
of that of the IC engine 43, a different fluid (i.e. with lower
vapor pressure inducing higher thermodynamic efficiencies) can be
utilized as the working fluid for the MWHE. The working fluid
circulating inside the circuit of the MWHE is pressurized by pump
87 and receives a first heat addition process inside side 83a of
the converter formed by the two separate loops 83 and 83a. This
pressurized fluid is then injected through hydraulic path 68 and
injector 69. Converter 88, represented in FIG. 17, can be formed by
the combinations of the converters formed by bodies 70, 73, 75, 25a
and 25b, and the converter formed by the jacket surrounding the EGW
3b in FIGS. 15, 16, and/or converter 103 described in FIG. 18. Back
to FIG. 17, liquid fluid enters converter 88 and expands
immediately. At the outlet 76, a superheated desired mass of vapor,
with a certain energy content, is regulated by valves 77a and 77b
(or a three-way valve 77, FIGS. 15, and 16) so that the proper
amount of steam is admitted by expander 1 and AEF 11. Expander 1,
provides the propulsion system for a compressor system 2, or any of
the oxygenators described in FIG. 14. AEF 11 instead utilizes the
excess steam to transform it into useful energy by direct or
indirect coupling with crankshaft 44. Pressure and temperature
sensors are positioned inside converter 88 providing thermodynamic
information via electronic signals 91 processed by a computerized
unit 92, or a sub-computer system, indicated by "S" in the
drawings, specialized only to optimize the operation of one of the
miniaturized engine sub-components (i.e., expander, imploder,
converter). Computerized unit 92 monitors and controls the amount
of steam to the various expanders through actuators/valves 89. For
example, actuators 89 can be electrical motors or pneumatically
actuated motors that regulate valves 77a and 77b. When the IC
engine 43 is cold started, computer 92 activates pump 87 through
the electric connection 90 only when the temperature of converter
83 or converter 88 reaches a pre-set level. Pump 87 could also be
entirely mechanical (i.e. positive displacement) and activated
through mechanical links by the IC engine 43. Again, when pump 87
is active, the fluid receives heat from converter 83a before being
injected inside converter 88. Inside converter 88 pressure and
temperature of the rapid forming vapor is proportional to the
amount of heat transferred from exhaust gases 80. All of the
expanders (i.e. 1a, 1, 1b, 11) utilized by the MWHE are controlled
by computer 92 and can be operated in a pulsed or continuous
manner. For example, through computer 92, valve 77b and 77a can be
kept partially closed causing a rapid increase of the circuit
pressure. When the accelerator of IC engine 43 is pressed, valve
77b and/or 77a can be set open and a surplus of torque is
temporarily available to the IC engine 43. If the IC engine 43 is a
large diesel engine, the pressure inside circuit 76 can be adjusted
such that boost power can be provided by AEF 11 to the engine every
time the load is maximum (i.e. Truck or Bus facing
steady-to-accelerating conditions). If the IC engine 43 is a
performance engine, valve 77b can be operated such that
overpressures are available at the engine intake manifolds allowing
the injection of more fuel leading to increased overall engine
power. If computer 92 is set to operate in a continuous power mode,
valves 77b and 77a can be actively adjusted to provide power at all
times. Probe 91 inside converter 88 provides the necessary
thermodynamic parameters to computer 92 which is also able to
shut-down the MWHE in case of overpressure, or any anomaly
developed in the MWHE circuit. When MWHE is shut-down due to
anomalies, computer 92 sets valve 97 open and discharges steam back
to the condenser 86, or, if the fluid is water, into the
environment. In this case, to avoid overheating of the converter
formed by channels 73, FIGS. 15, and 16, fins 134, FIG. 15A are set
open by computer 92 (or manually). When fluid in the MWHE flows
through valve 97, or is lost due to breakage of the circuit, an
optical and/or audio alarm is activated through an electrical
connection 114, or via computer 92. In general, computer 92 is a
control system able to monitor analog or digital inputs
proportional to crankshaft 44 RpM via sensor 55, AEF 11 speed via
sensor 56, EW 6 speed via sensor 115 (as described in FIGS. 3A, and
3B). These electronic signals (conditioned by a conventional
Input/Output interface) are processed by computer 92 which
regulates the positions of the various valves and actuators
accordingly (i.e. servo motors 112, via electrical connections 113,
as described in FIGS. 3A, and 3B). Computer 92 can be formed by a
microprocessor structure user programmable or customizable by the
insertion of specially mapped memories (i.e. pulsed or continues
mode operation of the miniaturized waste heat engine).
[0054] In FIG. 17A the hydraulic circuit of the MWHE utilizes a
pressurized tank 125 as a way to accumulate excess steam rather
than dissipating it through the AEF 11 utilized in FIG. 17. As
described earlier, excess steam is produced because the heat
produced by the engine provides more energy than that required to
only power an oxygenator. However, this excess energy can be
accumulated and returned to the IC engine in the form of boost
pressure. By having such a high pressure availability when the IC
engine is accelerating from idling RpM to high RpM, it is possible
to obtain significantly increased IC engine performance since more
fuel can be burned given the increased availability of oxygen. In
FIG. 17A, steam drives only an oxygenator designed to provide large
mass flow rates of oxygen to the IC engine regardless of its number
of RpM. If converter 88 generates too much steam, the mass flow
rate of fluid pumped by pump 87 can be reduced. This could cause a
significant temperature increase inside the converter. The excess
energy from converter 88 can be utilized to provide very large mass
flow rates of air at high pressures by accumulating the excess
steam inside tank 125. This configuration is particularly
advantageous when the IC engine is operated in an urban cycle
(continuous accelerations and decelerations). Excess steam is
regulated by valve 77a connected to tank 125 through insulated
piping and joint 126. Again, the pressure inside tank 125 is
adjusted and controlled by computer 92. If the pressure inside tank
125 increases beyond a pre-set threshold, valve 132 is set open by
computer 92 and steam condenses inside radiator 86 via piping 10.
If an imploder system is dimensioned to condense the same mass of
superheated vapor entering the expander (i.e. 1c and "I", in FIG.
8), then radiator 86 can be eliminated. If the IC engine idles for
long periods the overall heat converted by converter 88 might not
be sufficient to provide large amounts of oxygen when requested by
a sudden acceleration. In fact, Expander 1 might be in a situation
where the mass flow rate of steam is insufficient to provide enough
propulsion for its CW 2a. In this case, computer 92 opens valve
131, discharging steam pressure previously accumulated directly
through expander 1. The increased pressure inside hydraulic path
130 does not affect valve 77b since a check valve 127 prevents back
overpressures inside hydraulic circuit 76. Valves 131 and 132 are
controlled by actuators 128 and 129, which are driven by computer
92. Tank 125 is thermally insulated through insulating materials or
through a jacket 133 in which a vacuum can be established through
valve 124.
[0055] Converters with a poor heat transfer efficiency can be made
by simply winding a coil in thermal contact with the IC engine
exhaust manifold, and/or muffler. To obtain an optimized transfer
of energy from the exhaust gases to the MWHE, a compact and simple
converter capable of sustaining severe pressure fluctuations is
represented in FIG. 18. Exhaust gases enter tube 98 flanged and
sealed by seal 99 and allowing the connection of multiple
converters in series or parallel so as to form a bank of
converters. The number of converters utilized depends on the mass
flow rate requirements and the amount of waste heat to be
recuperated. Hydraulically sealed connections between various
converters can also be achieved through universal joints 107 shaped
in any geometry to accommodate the IC engine compartment available
space (i.e. elbows with variable angles of inclination). The length
and diameter of tube 98 combined with the number of internal fins
100 and the distance between the outer surface of tube 98 and the
inner surface of tube 110a determines the amount of heat transfer
capability of the converter. This heat transfer rate will also be
proportional to a certain mass flow rate of the MWHE's working
fluid. Fins 100 form a hydraulic path forcing the fluid to have a
relatively long residence time inside the converter. Furthermore,
this path forces the fluid to have intimate contact with the inner
surfaces of the converter, favoring an extremely rapid heat
transfer. Water can be injected inside the converter through one of
the inlet/outlet 101, 101a or 102. The converter is symmetric and
inlets and outlets can be exchanged. Generally, to improve the
converter efficiency, the MWHE fluid inlet port should be chosen at
the end of the exhaust gas hydraulic circuit (as far as possible
from the combustion chambers). Arrow 105 represents liquid water,
relatively cold, injected from inlet 101 inside a converter (here
represented open). As soon as water is injected it expands,
changing its specific volume by a factor of several thousands. This
thermodynamic expansion provokes extremely rapid steam/water
accelerations inside the chamber formed by the outer surface of
tube 98 and the inner surface of tube 110a concentric with tube 98.
Heat is added to the water, which becomes steam 106. While steam
travels inside the path formed by fins 100, its pressure and
temperature rapidly increase, making it superheated before it exits
outlet 102. The number of fins 100 is variable and the inlet/outlet
ports can be welded or threaded on the end cups sealing the jacket
formed by tube 98 and 110a. Inlet ports 101a provide a sealed
penetration for temperature or pressure sensors. If these ports are
not utilized they can be simply plugged. To minimize heat losses
from the converter to the surrounding environment, the converter
can be thermally insulated by wrapping it with insulating material
104. To further improve thermal insulation, a vacuum chamber 110 is
formed by inserting another concentric cylinder surrounding tube
110a (sealed with the end cups). Air can be evacuated during
manufacturing or through valve 109. If the heat transfer between
exhaust gases and the fluid of the MWHE is optimum, the temperature
of the exhaust gases might drop so severely that water produced
during the combustion of fuel would start condensing toward the end
of the last converter 98 of a bank of converters. By utilizing
valve 108 inserted in one of the coupling joints 107 positioned in
the lower point of the converter bank (or even if it is a single
converter), condensed water in the exhaust gases can discharge
without accumulating inside tube 98, minimizing corrosion. If the
IC engine is equipped with a catalytic converter, the converters of
the MWHE have to be inserted after the catalytic converter, or
computer 92 has to be programmed to produce steam in quantities
that do not lower the exhaust gases temperature to levels that
would damage or impair the correct functioning of the catalytic
converter.
* * * * *