Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to a fuel
saving device for internal combustion engines.
During normal operation of a typical gasoline
powered automobile engine, a standard carburetor intro-
duces by means of jets a fine liquid fuel spray-type
mist into a filtered air stream and delivers the
resulting air-fuel mixture to the engine combustion
chamber via the intake manifold of the engine. As is
well known, efficient combustion of the fuel in the
combustion chamber will depend upon the size of the
liquid fuel particles in the air-fuel mixture. The
larger the particles, the slower will be the combustion
process, the reason being that hydrocarbon fuels such
as gasoline can only be burned (oxidized) in vapor form
-- hence, the combustion of an air-fuel mixture can
only occur down to the evaporating surface of the fuel
particles. Accordingly (and presupposing an adequate
supply of oxygen from the air), it will be apparent
that the speed of the combustion process will be
enhanced to the extent that the fuel delivered to the
engine from the carburetor is already in vapor form or
the fuel particle size is minimized.
When the liquid fuel spray from the carbur-
etor jets contacts the filtered air stream in the
venturi section of the carburetor, a process of surface
evaporation begins. Since heat energy is required to
facilitate this process, heat is taken from the air
stream and the liquid fuel particles travelling toget-
~her as a mixture. In the absence of an additional
source of heat energy to maintain the temperature of
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the mixture, the temperature consequently decreases
downstream from the point where the liquid fuel spray
and the air stream first come into contact. This nega-
tive temperature gradient decelerates the evaporation
rate of the liquid fuel particles in the air-fuel mix-
ture. As a result, the size of liquid fuel particles
at the point of entry into the combustion chamber will
be relatively large and only a relatively small amount
of the fuel will be in true vapor form.
When the air-fuel mixture in the combustion
chamber of the engine is ignited, the fuel vapor within
the mixture combines with oxygen from the air and com-
pletes the intended combustion process. The resulting
heat energy is used, firstly, to elevate the tempera-
ture of the mixture back to the original air and fuel
intake temperature levels, and then to a level which
produces the pressure required to drive the engine
piston during its work stroke. During the elevated
combustion temperatures some heat is also used to fur-
ther evaporate fuel particles still in liquid form.
Since the foregoing processes take placewithin a very short time span, the fuel does not have
enough time to fully vaporize and fully oxidize in the
engine combustion chamber -- the combusion is incom-
plete. Consequently, the exhaust emits combustiblefuel together with the products of complete combustion.
Not only is the emission of combustible fuel wasteful
from the point of view of fuel economy, but it also
represents exhaust pollution.
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Flow turbulence is another factor which will
bear upon evaporation of fuel in an air-fuel mixture.
When surface evaporation of a liquid fuel particle
first begins, a molecular fuel vapor cloud, at equili-
brium concentration with a surrounding layer of air,develops in the immediate neighbourhood of the parti-
cle. For further evaporation of the fuel particle to
take place, dissipation of the saturated fuel vapor
cloud is required. In a carburetor, dissipation
results from the turbulence represented by cross-flow
velocity components both tangential and normal to the
velocity vector of the main air-fuel mixture flow.
Such turbulence also facilitates heat energy transfer
from within the air-fuel mixture flow to make further
evaporation of the liquid fuel particles possible.
Thus, it will be apparent that the fuel evaporation
process and consequently fuel economy may be impeded if
the turbulence within the air-fuel mixture flow is
insufficient to dissipate fuel vapor clouds from around
the liquid fuel particles which they initially
surround.
In conventional internal combustion engines,
which receive fuel via a standard carburetor, the fuel
combustion process is not ideal -- fuel is wasted
resulting in exhaust pollution. The inventors have
found that the problem, at least in part, can be traced
to the fact that a significant amount of fuel leaves
the carburetor still in liquid particle form and there
is insufficient time for the particles to completely
evaporate and combust in the engine combustion chamber
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before the chamber is exhausted. To reduce the amount
of such waste and pollution, the inventors have
developed a fuel saving device for connection between
the carburetor and the intake manifold of the engine.
In a broad aspect of the present invention,
there is provided a fuel saving device for connection
between an air-fuel mixture flow output opening of a
carburetor and an output opening of the intake manifold
of an internal combustion engine. The device includes
an input opening for receiving an air-fuel mixture flow
from the output opening of the carburetor and an output
opening for delivering an air-fuel mixture flow to the
input opening of the intake manifold. In addition, the
device includes means for maintaining the input opening
of the device in flow communication with the output
opening of the carburetor and means for maintaining the
output opening of the device in flow communication with
the input opening of the intake manifold. Conditloning
means is included between the input and output openings
of the device for heating and turbulating the air-fuel
mixture flow received at the input opening of the
device and for delivering the heated and turbulated
flow to the input opening of the engine intake manifold
via the output opening of the device.
The conditioning means comprises means for
dividing the air-fuel mixture flow received at the
input opening of the device into a plurality of
separated and redirected flows and then recombining the
separated and redirected flows into a single recombined
flow. The dividing means includes a plurality of heat
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exchan~e tubes for carrying the separated flows, each
of the tubes being nonlinearly configured so as to turn
the direction of the flow within the tube between an
inlet of the tube and an outlet of the tube. Further
the conditioning means comprises means for heating the
plurality of separated flows.
The fuel saving device is for adding both
heat and turbulence to the air-fuel mixture flow from
the carburetor, thereby enhancing the liquid fuel
evaporation process. The separation, redirection and
recombination of the air-fuel mixture flow contributes
to overall turbulence. Also, improved heat transfer
characteristics from a source of heat to the air-fuel
mixture are permitted when the single flow is separated
lS into a plurality of separated flows, each of which is
turned as described above. The separation of the flow
is to provide an expanded heat transfer surface area
within the heat exchange tubes. The turning of the
separated flows is to facilitate evaporation due to
inertia forces which will act on liquid fuel particles
in the flows. Around turns, such forces will separate
liquid fuel particles from the flows bringing the
particles into direct contact with the expanded heat
transfer surface provided by the walls of the tubes,
thereby facilitating improved turbulent heat transfer.
In a preferred embodiment of the present
invention, the fuel saving device comprises an intake
plenum having an input opening for receiving an
air-fuel mixture flow from the output opening of a
carburetor and a discharge plenum generally disposed
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below the intake plenum, the discharge plenum having an
output opening for delivering an air-fuel mixture flow
to the input opening of an engine intake manifold.
Means are provided for maintaining the input opening of
the intake plenum in flow communication with the output
opening of the carburetor. Similarly, means are
provided for maintaining the output opening of the
discharge plenum in flow communication with the input
opening of the intake manifold. In addition, the
device includes a plurality of heat exchange tubes for
providing flow communication between the intake plenum
and the discharge plenum, each tube having an inlet in
flow communication with the inta~e plenum and an outlet
in flow communication with the discharge plenum. Each
inlet is for receiving outwardly from the intake plenum
a portion of the air-fuel mixture flow received at the
input opening of the intake plenum. Each outlet is for
delivering the portion received at the corresponding
inlet inwardly to the discharge plenum. Each of the
tubes is nonlinearly configured to turn the direction
of the separated flow within the tube between the inlet
of the tube and the outlet of the tube. Further, the
device includes means for heating the plurality of
tubes.
As will be appreciated, the air-fuel mixture
flow received at the input opening of the intake plenum
is divided in the intake plenum into a plurality of
separated flows, each of which flows proceeds through
one of the plurality of tubes. The separated flows are
then recombined in the discharge plenum. Necessarily,
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the air-fuel mixture flow is turned and redirected
because it (in its separated portions) is first
directed outwardly from the intake plenum and, subse-
quently, inwardly to the discharge plenum. Turning
must occur in between to have the flow first move "out"
then move "in". Further, between the "outward" and
"inward" turning and redirecting, there is a necessary
downward turning and redirecting because the discharge
plenum is generally disposed below the the intake
plenum.
As previously indicated, such separation,
redirection and recombination contributes to overall
turbulence. Also, improved heat transfer characteris-
tics are permitted. By heating the heat exchange
tubes, the separated flows flowing within the tubes are
in turn heated. In effect, the walls of the tubes
provide an expanded heat transfer surface, and the
overall heating tends to be faster and more uniform
than with a single combined flow where the centre of
the flow is insulated to a greater degree by outer
layers of the flow. In addition, the turning of the
separated flows within the tubes enhances heat transfer
because the liquid fuel particles of the flows are
driven towards the walls of the tubes around the turns.
The separation, redirection and recombination
referred to above may be readily achieved with the use
of nonlinear tubes each having two 90 bends (viz. the
form of a "C" with right angled corners). Differing
shapes could be used (for example, a smooth semi-
circular or semielliptical "C"), but 90 bends are
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considered preferable because their abruptness contri-
butes to turbulence.
Advantageously, the intake plenum and the
discharge plenum each have a cylindrically walled con-
S figuration around a common cylindrical axis extendingdownwardly through the intake plenum then downwardly
through the discharge plenum. The intake plenum and
the discharge plenum may be formed in an upper portion
and a lower portion, respectively, of a single cylin-
drical enclosure. This configuration can contribute toan overall compact structure in which each of the heat
exchange tubes leads radially outwardly from the intake
plenum, then downwardly, then radially inwardly to the
discharge plenum, all of the tubes having substantially
the same size and shape.
Various means for heating the heat exchange
tubes are contemplated within the scope of the present
invention. Preferably, the heating means comprises a
jacket enclosing all of the tubes, the jacket having an
inlet for receiving a heated flow (gaseous or liquid)
and an outlet for discharging the heated flow. Advan-
tageously, the heated flow may be a flow of hot coolant
liquid from a cooling system of the engine. In this
case, the heating means includes means for connecting
the inlet of the jacket in flow communication with
means for delivering hot coolant liquid from the engine
cooling system and means for connecting the outlet of
the jacket in flow communication with means for return-
ing the hot coolant to the engine cooling system. The
heated flow may be derived from other sources - for
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example, in the case of an air cooled engine, hot air
heated by the engine may be ducted around the heat
exchange tubes.
The present invention lends itself to a com-
pact construction with simple and relatively few parts.
In a preferred embodiment, the intake plenum and the
discharge plenum each have a cylindrically walled con-
figuration around a common cylindrical axis, the intake
plenum and the discharge plenum being divided by a
common wall which forms on one side the bottom of the
intake plenum and on the other side the top of the dis-
charge plenum. The common wall could be in the nature
of a flat disc but, to compensate for stresses that can
develop as a result of thermal expansion, it preferably
has an upward curvature.
Utilizing the present invention, significant
savings in fuel economy and reduction of exhaust pollu-
tion can be achieved - but without corresponding degra-
dation in vehicle performance.
The foregoing and other features and advan-
tages of the present invention will now be described in
more detail with reference to the drawings.
Figure 1 is a cross-section side elevation
view of a fuel saving device in accordance with the
~5 present invention.
Figure 2 is a top view of the fuel saving
device shown in Figure 1.
Because exhaust pollution is reduced, it is
considered that the present invention can substantially
obviate or remove the need for catalytic converters,
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the latter of which are expensive and somewhat danger-
ous as a result of high temperatures and back pressures
which develop during operation - not to mention the
adverse effect which catalytic converters have on
vehicle performance.
The fuel saving device (generally designated
30) shown in Figures 1 and 2 was developed for a 1967
Ford Falcon "Futura"~. It was a standard production
model having a 200 cubic inch six-cylinder engine and
an automatic transmission. Hence, as will be readily
apparent to those skilled in the art, certain detailed
aspects of the design now to be described tfor example,
the mounting arrangement for the device) will be pecu-
liar to the particular application and will require
modification for different applications.
In Figure 1, a portion of a standard carbure-
tor (general~y designated 10), and a portion of an
engine intake manifold (generally designated 20), are
both shown in broken outline. Fuel saving device 30 is
connected between the air-fuel mixture flow output
opening of the carburetor at 15 and the input opening
of the intake manifold at 25. Carburetor 10 and engine
intake manifold 20 are not shown in Figure 2.
Fuel saving device 30 includes a cylindrical
intake plenum 40 having an input opening 42 for receiv-
ing an air-fuel mixture flow from output opening 15 of
carburetor 10. Also, the device includes a discharge
plenum 50 having an output opening 52 for delivering an
air-fuel mixture flow to input opening 25 of intake
manifold 20.
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As can be seen in Figure 1, intake plenum 40
and discharge plenum 50 are aligned around a common
cylindrical axis designated 70. The two plenums are in
fact upper and lower portions respectively of a cylin-
drical enclosure 75 divided by a common wall 80. Theupper surface or side ~2 of wall 80 forms the bottom of
intake plenum 40, and lower surface or side 84 of the
wall forms the top of discharge plenum 50. Wall 80 has
an upward curvature to compensate for stresses that can
develop as a result of the thermal expansion. A down-
ward curvature is considered to be undesirable because
liquid raw fuel could tend to pocket in the depression
and be sprung upwardly into heat exchange tubes 90
(referred to next) as a result of possible springing in
the wall under stress due to temperature variations.
A plurality (twelve to be precise) of heat
exchange tubes 90 interconnect intake plenum 40 and
discharge plenum 50 for providing flow communication
therebetween. Each tube has an inlet 91 in flow com-
munication with the intake plenum and an outlet 92 inflow communication with the discharge plenum. All the
tubes have substantially the same size and shape, each
tube leading radially outwardly from intake plenum 40,
then downwardly from around a sharp elbow 93, then
radially inwardly to discharge plenum 50 from around a
sharp elbow 94. As can best be seen in Figure 2, the
tubes are uniformly spaced circumferentially in rela-
tion to common axis 70 (which shows as a point in
Figure 2).
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Heat exchange tubes 90 are enclosed by a
jacket 100 which has an inlet 102 for receiving a flow
of hot coolant liquid and an outlet 104 for discharging
the flow. The hot coolant liquid is supplied by the
cooling system (not shown) of the engine of which in-
take manifold 20 forms part. In the Ford vehicle
referred to above, as in many vehicles, the engine
cooling system includes a thermostatically controlled
outer loop from the engine block through the radiator
and back to the engine block, and an inner loop from
the engine block through a heater (used to warm the
interior air of the vehicle) and back to the engine
block. A coolant pump, common to both loops for hot
coolant leaving the engine block, circulates coolant
through the system. Fuel saving device 30 was connect-
ed in the inner loop in a parallel flow path with the
the heater - coolant inlet pipe 106 leading from the
inner loop on the upstream side of the heater to lnlet
102 for delivering hot coolant to the device from the
engine cooling system; and coolant return pipe 108
leading from outlet 104 to the inner loop on the down-
stream side of the heater for returning the coolant to
the engine cooling system. In passing between inlet
102 and outlet 104, the hot coolant from the engine
cooling system conveys heat to heat exchange tubes 90.
Fuel saving device 30 includes two mounting
flanges 60 and 65 which were designed for compatibility
with the Ford vehicle referred to above. Input opening
42 of intake plenum 40 is maintained in flow communica-
tion with output opening 15 of the carburetor by
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bolting the carburetor to carburetor mounting flange
60, the latter of which includes two threaded bolt
holes 62 for the purpose (the corresponding bolts are
not shown). A gasket 19 provides sealing for the
connection. Output opening 52 is maintained in flow
communication with input opening 25 of intake manifold
20 by bolting lower flange 65 of the device to the
intake manifold. Two bolts 67 are used, and a gasket
29 provides sealing for the connection. Pipe 110
leading into discharge plenum 50 provides a connecting
path to the "positive crankcase ventilation~ (PCV)
valve thereby facilitating engine ventilation as
intended by the vehicle manufacturer. Shaft 115,
extending from carburetor mounting flange 60 (see
Figure 2), is a mounting shaft set and aligned for
compatibility with the existing carburetor control
linkage of the vehicle. A temperature sensor by-pass
return hole 61 for the choke control of the original
carburetor has been duplicated and properly aligned in
flange 60.
In the operation of fuel saving device 30, an
air-fuel mixture flow from carburetor 10 flows down-
wardly into intake plenum 40 where it is diverted
outwardly into inlets 91 of heat exchange tubes 90.
The upwardly curved shape of surface 82 on wall 80
assists the uniform dispersion of the incoming flow to
the heat exchange tubes. The resulting dispersion and
change in flow direction adds desirable turbulence to
the flow resulting in break-up of liquid fuel particles
in the flow.
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Within each heat exchange tube 90, further
turbulence is induced by the two 90 corners which the
now separated 10ws must negotiate on their way to dis-
charge plenum 50. The heat exchange tubes, being
heated as previously described by hot coolant from the
engine cooling system, facilitate heat transfer to the
air-fuel mixture flows thereby encouraging evaporation
of liquid fuel particles within the flows. In this
regard, it will be appreciated that the changes in flow
direction within the heat exchange tubes themselves
advantageously enhance the evaporation process. Iner-
tia forces acting on the liquid fuel particles as they
are required to negotiate the corners in the heat
exchange tubes tends to develop a liquid fuel film
against the hot inside walls of the heat exchange
tubes. The heated film, in direct contact with the
inside walls, rapidly evaporates and is carried away by
and mixed into the passing air-fuel mixture flow.
Upon entry to discharge chamber 50 through
outlets 92, the separated flows recombine into a single
air-fuel mixture flow and undergo a further change in
flow direction (viz. from horizontally inwardly to
downwardly), all of which adds further turbulence.
Finally, the downwardly flowing air-fuel mixture flow
is delivered via output opening 52 to input opening 25
of engine intake manifold 20 from where it is then
distributed to engine combustion chambers (not shown)
in the usual manner.
Using the Ford vehicle referred to above both
with and without fuel saving device 30, stationary and
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road tests demonstrated that a significant improvement
in fuel efficiency (and consequently less e~haust pol-
lution) could be achieved with the device. Visually, a
simple "white cloth" exhaust emission test verifiea a
reduction in unclean emissions. In conducting the
tests, substantial efforts were made to ensure that any
improvement in performance could not be attributed to
changes in vehicle operating characteristics, and the
same test route was followed under similar traffic
conditions. The vehicle was fully tuned to factory
specifications prior to each test for the purpose of
starting with the same initial conditions, such as air-
fuel mixture ratios, timing and the like.
It is significant to bear in mind that the
successful results indicated were achieved without
noticeable degradation in the performance of the vehi-
cle under test. No engine operating changes or short-
comings such as overheating, loss of power, or loss of
response were detected. -
The general compactness and simplicity in
construction of fuel saving device 30 is also of signi-
ficance. As used on the Ford vehicle under test,
cylindrical enclosure 75, having an outside diameter of
1 5/8 inches, had a length of about 3 inches - the
latter of which corresponds to the overall height of
the device. Jacket 100 had a vertical height of about
1 3/4 inches and an outside diameter of abut 4 1/8
inches. ~he twelve heat exchange tubes 90 all had sub-
stantially the same size and shape, their outside
diameter being about 3/8 inches. Coolant inlet and
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coolant return pipes 106 and 108 each had an outside
diameter of about 5/~ inches.
One item that did require some minor innova-
tion not considered to bear upon the test results was
the making of a somewhat shallower air cleaner. Not-
withstanding the compactness of fuel saving device 30
as used for the tests, the height of the device plus
the height of the original carburetor assembly would
not permit the vehicle hood to be closed. This problem
was circumvented by replacing the standard air cleaner
which came with the vehicle with the shallower air
cleaner. An alternate solution would have been to
install a clearance Nbubble~ in the hood.
It will be appreciated by those skilled in
the art that many modifications and changes within the
scope of the present invention are possible. Indeed,
it is to be plainly expected that at least some changes
from the specific embodiment shown in the drawings will
be required from time-to-time, if for no other reason
but to adapt the device for different vehicles having
different engine intake manifold and carburetor system
geometries. However, it is also to be expected that
other aspects of the design will vary for different
vehicles depending upon the vehicle and the style and
size of the engine and carburetion system. For fuel
saving device 30, some testing was required to deter-
mine the number and size of heat exchange tubes 90
which were considered to achieve an optimum or near
optimum performance for the vehicle and engine and
carburetion system involved. This will also be true
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for different vehicles having different engine and
carburetion systems. Generally speaking, the number of
heat exchange tubes and their diameters will be a
function of engine displacement. Their length will be
a function of the coolant used. If there are too few
heat exchange tubes, or if their equivalent length is
too long, then the effect of the fuel saving device may
be to cause unwanted throttling. If the equivalent
length of the tubes is too short, then insufficient
heating in the tubes may be the result. If there are
too many heat exchange tubes, no additional advantage
may be gained from those that are extra, or, there may
be a reduction in turbulence sufficient to adversely
reduce the amount of heating which can take place in
the tubes.
Fuel saving device 30 shown in the drawings
was made from copper with the exception of flanges 60
and 65 which were made from steel. Obviously, however,
other metals having good heat transfer characteristics
could be used.
Other alternatives which are contemplated
include the incorporation of flanges such as flanges 60
and 65 as part of the coolant jacket and the use of
Uthrough bolts" from the carburetor through the fuel
saving device to the engine intake manifold. It is
also considered that a fuel saving device in accordance
with the present invention may be incorporated directly
by casting into the lower part of a carburetor or into
the upper part of an engine intake manifold.
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Further, and while the geometry and configu-
ration of fuel saving device 30 is considered to embody
features which are advantageous, it is to be understood
that means differing from the specific means shown may
be utilized for the purpose of usefully heating and
turbulating an air-fuel mixture flow. As previously
indicated, the invention may be implemented with
air-cooled engines by ducting coolant air heated by the
engine to the fuel saving device. In such a case, heat
exchange tubes such as heat exchange tubes 90 may be
equipped with external fins to better facilitate heat
transfer between the hot air contacting the outside of
the tubes and the air-fuel mixtures flowing within the
tubes. Alternately, or additionally, heat transfer
fins may be utilized inside the heat exchange tubes.
Various other changes and modifications will
occur to those skilled in the art, and it is to be
understood that the invention is not considered to be
limited to the particular embodiment described above
with reference to the drawings.
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