Note: Descriptions are shown in the official language in which they were submitted.
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: This invention relates to an improvement in conventional
'.' carburetors used in conjunction with internal combustion engines.
'. The basic purpose of a carburetor is to mix a hydrocarbon fuel such
' as gasoline and air to forn a combustible mixture to power the~' .'
pistons o-f an engine. A theoretically perfect carburetor should
vaporizb.the -fuel completely as it is discharged at the main fuel ~ .
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nozzle of the carburetor and should maintain the vaporized con- ~
'; dition of the fuel:through its delivery to the engine cylinders. " :.
. Ho~ever, such.perfect vaporization exists only in theory.
10 Droplets:of unvaporized gasoline are considerably.heavier .' '
`' than the'gaseous mixture with which they are traveling. Their ..
`~ ; greater inertia causes them to continue in the diTection they are . .'' :
'~ moving when the mixture turns to follow a passage or to enter .
another passage. If possible, the.heavier particles continue ..
' straight ahead until they reach a dead end, rather than to mi~ke the '.
~: desired turns. .This results in the.center cylinders of a cylinder .' ':~
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` bank in many engines being run on a richer mixture than the end
. ~ cylinders Better mixture distribution is one a.rgument in favor -
-: : of special multiple carburetors and specially "tuned" intake :
~:.'' 20 manifolds.
:~: Good m~xture distribution is important to smooth engine
operation,.ev.en:thro~tle response, reasonable fuel mileage and
; . decreased exhaust emissions. Engine manufacturers to date have
attempted to:correct this problem by heating the mixture of fuel
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~ and air as it leaves the carburetor, thereby.attempting to more
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~ . completely vaporize the fuel m the mixture. This is typically
:~ `` done by ro~ting exhaust gases.to heat the intake manifold. Heat
.~ also is applied by many manufacturers by using a.heated air
cleaner'.which sends ho~ air to the carburetor on a cold engine and '.
~ / 30 shortens the warmup time. ~.
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The area of the manifold that is heated is directly below
the carburetor. This causes the mixture of gasoline and air to
pass through a high temperature area immediately after leaving the
carburetor. If the temperature is high enough, most of the fuel -~
~ill theoretically remain vaporized on its way to the cylinders. -
The application of heat at the intake manifold does not
work as effectively in practice as in theory. First, there is a
large volume of air and fuel which must be heated as it passes
rapidly along the intake manifold walls. The retention period for
the mixture within the limited space available at the conventional
intake manifold is very brief and there is not much opportunity -~
- to thoroughly heat the large volume of fuel-air mixture. Further-
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; more, more heat will obviously be applied to that portion of the
`~ mixture adjacent to the intake manifold walls than to the inner
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.1 volume of the mixture.
Heated intake manifolds improve the operation of an engine,
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but do not asslst in improving the power output. In a full throttle
`~ ~ condition, an engine will develop more p~wer if the air-fuel mixture
is cool rather than heated. A cool mixture is more dense than a
warm mixture, which means that if the mixture is cool more gasoline
and air can be packed into the combustion chamber than is possible
when using a mixture that has been thinned out by heat. Thus for
maximum horsepower, the engine must be warm and the mixture of fuel
and gasoline must be cool.
The present disclosure utilizes a simple diverting heat ~ -
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exchanger to thoroughly vaporize all of the incoming atomized
gasoline, along with a portion of the incoming air. It interrupts ~ -
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the normal flow of the mixture through the venturi of the carburetor, `
diverting it through an elongated passageway where heat is applied
to the mix~ure to completely vaporize the gasoline. This is
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preferable to heating of the new gasoline, which results in loss of
evaporated gasoline and causes flooding of the engine when it is
warm This device eliminates the need for the application of heat
; to the intake manifold. It allows the engine to be run on a cooler
mixture than is practical under present engine design.
` The fuel vapor generator described herein is designed for
use in conjunction with a conventional internal combustion engine
that utilizes a carburetor with a main nozzle through which atomized
fuel is discharged at the venturi of the carburetor. It structurally
comprises a heat conductive member located at the exterior o the
carburetor, having an elongated passageway with open inlet and
~ outlet ends. The inlet end of the passageway is positioned within
;~ the carburetor venturi at a location such that the atamized fuel
leaving the main nozzle is directed into the passageway. Approxi- ~`
m tely one fourth to one sixth of the incoming air is also received
within the inlet of the passageway. The fuel and air are pulled
. through the passageway by vacuum pressure applied to the outlet end
of the passageway, which projects into the carburetor venturi down-
stream from the main nozzle. Mesh screens are interposed across the
passageway to assist in heat conduction and to atomize and break up
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~` any droplets of fuel. A jacketed heat exchanger can be utilized about
. the portion of the member exterior to the carburetor to add heat as
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` b~ required for proper vaporization of the fuel.
`~ The basic rnethod of vaporization relates to the withdrawing
of the atomized fuel and a portion of the air entering the carburetor
$ by directing the fuel and air into an elongated hollow mernber exterior
~ to the carburetor and thermally insulated from the carburetor so as
- ~ to eliminate heating of the carburetor by the vaporizing procedure.
The atomized fuel and air is directed back into the venturi of the
carburetor downstream fron the main nozzle. Heat is applied to the
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fuel and air mixture at the exterior of the carburetor.
Fig. 1 is a sectioned view of the present device in relation
to the venturi of a carburetor shown in schematic form in which the
device is installed;
Fig. 2 is an exterior pictorial view of the device apart
from a carburetor; and
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Fig. 3 is an end view looking toward the inlet and outlet
ends of the devic0 as seen from the left in Fig. 2.
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A physical example of the device is illustrated in Fig. 1,
~ whi~h schematically shows the basic portions of a carburetor with
- which the device is utilized. The simplified presentation of the
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carburetor elements is presented only by way of illustration.
.` Obviously, the device can be utilized in conjun~tion w~bh~many
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~, different forms of existing or future carburetors which incorporate the basic elements discussed herein.
This device is designed for use in a carburetor having one
or more venturis or throa~s through which a fuel-air mixture is `~
delivered to the intake manifold (not shcwn) of an internal combustion
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~ engine. The throat of the carburetor is generally indicated at 10.
r~ It includes a restricted area 11 commonly termed the '~enturi". A
~ main nozzle 12 directs fuel to the venturi in response to the vacuum
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pressure created by the venturi and operation of the engine. Fuel
may be delivered to the main nozzle 12 by any conventional means,
typically from a float bowl and main metering jet ~not shown). In
many carburetors additional venturis exist and are located about
the outlet of the main nozzle 12. Thes0 should either be removed ;
or the main nozzle replaced by a more simplified tube as illustrated
in Fig. l. In any respect, the main nozzle 12 should direct the
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incoming fuel to the inlet of this device as discussed below.
The device i~self basically comprises a hollow tubular
member 13 having an elongated interior passageway, illustrated as
being substantially U-shaped. The passageway could obviously have
other configurations and might be coiled, curved or bent in order
to properly fit within the existing space surrounding the carburetor
and engine. Ilowever, a simple elongated straight passageway having
a U-shaped configuration is both practical and useful.
` In the illustrated device, the hollow tubular member 13
is fabricated from cylindrical tubing. It has a subskantial length
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with respect to ~he width of the venturi 11 ~o provide a relatively
long passageway through which the fuel must pass. Member 13 is
bisected by a center plate 14 that extends across its full width.
;`~ Plate 14 terminates sho~t of an outer or closed end 15 of member
1,, .
13. It therefsre defInes an elongated U-shaped passageway extending
~`~ across the top of the device from an open inlet end 16 to outer end
~ ~ 15 and back along the lower portion of member 13 to an open outlet ;
- 17.
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~ ``. When the device itself is mounted at the exterior of the
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`~ 20 carburetor3 the inlet and outlet ends 16, 17 are projected into the ~
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`t carburetor venturi or throat. They are formed at opposite oblique
angles with respect to the axis of the member 13, so as to entrap ;~
a portion of the incoming air in the inlet end 16 and so as to
present a larger discharge area for appli.cation of engine vacuum
to the outlet end 17.
~ The object of this device is to heat fuel discharged from
;J the main nozzle 12 carried within a portion of the incoming air
entering venturi 11 to a temperature adequate to boil or vaporize
. any remaining liquid droplets of fuel in the mixture. The conduction
o heat is accomplished by construc~ing the walls of the passageway
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within member 13 from heat conductive material, such as copper or
aluminum. Heat transfer is enhanced by use of a series of metallic
screens of relatively fine mesh, directed across the full width of
the passageway as it leads away from the intake end 16 and to the
outlet end 17 of member 13. The screens 18 also assist in more
ccmplete vaporization of liquid fuel by physically breaking up
larger droplets of fuel as they pass through the fine mesh. Screens
18 should also be constructed of heat conductive material such as
copper or aluminum. The materials used in the device must also be
chemically inert to hydrocarbon fuel so as to not decompose during
use.
As the fuel and air mixture pass along the elongated passage-
way between intake end 16 and outlet end 17, it must be heated to a
temperature adequate to vaporize the remaining gasoline droplets.
This heat might be applied directly due to the proximity of the `
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device to o~her heated portions of the engine with which it is
~ utilized. A heat exchanger as such might not always be required. ~ -
;~ However, for more universal application~ it is desirable that an
enclosing jacket 20 be mounted about the member 13 to direct a
heated fluid about the exterior walls of member 13 during use of
~,~ the device. As illustrated, the jacket 20 is a cylindrical tube
having an enclosed end 21 spaced from the end 15 on member 13 and
-~ sealed along its end adjacent to the carburetor. Inlet and ou~let
connections 22~ 23 are provided for reception of cooling water ~
utilized in operation of the engine, heated exhaust gases or other ~ -
- l available heated fluids. They should be at a temperature of about
160F. Such fluid is circulated through the jacket 20 continuously
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~ ë~ during use of the device.
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The device should be thermally insulated from the carburetor
itself. Since heat is applied to the device, it is desirable that
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lQ673~?1
insulation be utilized to prevent the application of heat to the
walls of the carburetor. Such heat would tend to evaporate liquid
fuel in the float bowl (not shown), which might flood the engine
when it is running warm. Such evaporation is also undesirable when
the engine is at rest, since it makes initial starting of the engine
difficult when the bowl is dry. Thermal insulation can be provided
in the form of a surrounding bushing 24 that mounts member 13 through
the walls of venturi 11. Auxiliary brackets 25 (Fig. 1) can also be
utilized to mount the device to the carburetor as necessary. The
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~; 10 brackets 25 should also be constructed by way of a thermal insulating
bushing o~ other insulating structure.
; j This device can be installed on existing carburetors by
simply drilling a single hole through the body of the carburetor to
inject the inlet and outlet ends of the device into the venturi, with
; inlet end 16 in direct communication with the outlet of main nozzle ~ -
12 and outlet end 17 located in the venturi or throat of the carburetor
~; downstream from the outlet of main nozzle 12. The bushing or insulator
~'~ 24 can be in the form of a resin or plastic cement utilized to secure
the member 13 to the walls of the carburetor. The size and shape of -~
the device? varies according to the amount of ~uel needed and the
space available for installation at the exterior of a particular
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carkuretor. The rich or lean quality of the fuel-air mixture is
easily adjusted by positioning inlet end 16 in venturi 11. By directing
main nozæla I2 further into inlet end 16, and by moving outlet end 17
further into the carburetor, more vacuum will be exerted through the
passageway of the device, thereby drawing additional atomized fuel
* om main nozzle 12 into inlet end 16 of member 13. Proper adjustment
will divert about one fourth to one sixth of the incoming air into
inlet end 16. The member 13 can be fixed in place permanently or
,~ 30 can be releasably mounted so as to be axially adjus??table as desired.
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Figs. 2 and 3 show further structural details of an actual
working model of the device apart from a carburetor. The same
numerals utilized in Fig. 1 are applied to these figures to designate
the various elements of the device.
This invention arose from the experience of the inventor in
installing and maintaining liquid propane gas systems for warehouse
vehicles and operation and maintenance of a refrigeration plant.
This experience with vaporization of gases is now directed to the
vaporization of gasoline for use in an internal combustion engine. -
10 When using liquid propane, the resulting gas must be vaporized as ~
; completely as possible so as to be efficient for engine operation. ;
In refrigeration systems, the usual Freon gas must also be vaporized
for efficiency. The present invention resulted from an effort to ;~ -
build a device that would vaporize gasoline as completely as possible ;
to provide better combustion and fewer exhaust emissions.
` The development of this invention followed initial experi-
;`j mentation with use of an electric heat coil in the booster venturi ~ -
`1 of a carburetor. This failed because it is practically impossible
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to vaporize as much liquid fuel as is needed for typical automobile ~- ;
engines in such a small area. The heat also was detrimental because
.` of the resulting heat transfer to the carburetor itself. This caused
: ~ rapid evaporation of the gasoline in the carburetor bowl, releasing
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the hydrocarbons into the air after e-ngine shutdown and leaving the
~ carburetor bowl empty. The engine was therefore exceptionally hard
; ~ to start without excessive cranking power. Other proposed heat
exchangers were studied which applied heat inside the carburetor,
around the carburetor throat, or between the carburetor and intake
` ~ manifold. However, such heat application is self-defeating because
the fuel-air mixture is expanded so substantially as to cause a lower '!
air-fuel ratio and a mixture that is too lean for high power operation
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of an engine.
The theory of this disclosure is to provide complete com-
bustion by complete vaporization of gasoline mixed with cooled con-
densed air, which will result in even distribution o-f the complete
mixture to the cylinders. Realizing that this would not be accom-
plished within the carburetor, it was decided to design a fuel vapor
generator that would re-route the flow of -fu~l and a por~ion of the
incoming air which would stherwise have passed directly through the ~ -~
venturi of the carburetor. This partial mixture is directed into
passageways or tubing to the exterior of the carburetor and through
,: ~ ~ . .
~` a heat exchanger which might include a series of screens. It is
- ~ returned as vaporized fuel to the venturi, l~here it is mixed with
':f,'' cool incoming air. By use of this device, a much larger area or
volume is provided in which to vaporize the fuel and need for heat
in the intake manifold is eliminated. A cooler fuel-air mixture flow
to the cylinders results in a higher air-fuel ratio at idle, thus
educing exhaust hydrocarbon~.
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Several items contribute to the rapid evaporation and
vaporization in this device. First, the vacuum applied from the
venturi of the carburetor, which draws fuel and air through the
` elongated passageway permits boiling or vaporization of the liquid
i;~ .~.
at lower temperatures. Next, the series of screens atomize the drop--
lets of gas and assure more intimate conductive heat transfer * om
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the device to the liquid g~soline. Third, the conductive heat transfer
to the passagewa~ and screens from an exterior source of heat, which
might be a heated fluid (hot water or exhaust gas) surrounding the
elongated passageway exterior of the carburetor provide additional
heat needed for vaporization. Exterior heat is necessary to co~nter- -
act cooling action due to vaporization of fuel which would othe~wise
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~ ~" 30 tend to condense the fuel as fast as i~ is vaporized.
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~ Upon installation of the device in existing automobile
; engines, substantial gains in gasoline mileage have been demonstrated
without loss of acceleration ability. An analysis of the engine
opération has shown an increase in the air-filel ratio in comparison
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to normal engine and carburation settings. Analysis also has shown
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- more even distribution of the vaporized fuel to all cylinders at
high speed and high power operation. There is also a definite gain
in horsepower at higher speed engine operation. After rapid accel-
eration and succeeding deceleration in a conventional engine, large
- 10 amounts of llquid fuel are trapped in the intake manifold, resulting
in a high percentage of hydrocarbons which are lost through the -;
exhaust system. With this apparatus in use, it has been demonstrated
that vaporization of the fuel occurs to such a degree that a lesser
percentage of hydrocarbons is trapped in the intake manifold upon
such~deceleration.
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;`'~ To summarize the advantages of the device, one principal
~``i advantage is the ease o-f installation on most existing carburetors.
~` Furthermore, the device can readily be incorporated into the design
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of new carburetors, either a~ an integral part of the carburetor or
as a separable accessory. There are no moving parts in the product
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and no main~enance is required to keep it operating properly. By
~! re-Tauting the fuel-air mixture to the exterior of the carburetor9
~` the device provides increased volume in which to vaporize the fuel
~ beyond thait which would o~herwise be available wi~hin the carburetor.
Z~ '~ As an example, a six inch member provides a passage twelve inches
~ ~ ~ long for vaporizing fuel. The device takes advantage of heat that
2.'~ is readily available fr~n the engine itself or from the cooling
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. system or exhaust system of the engine. It can be readily adjusted
by axially positioning it for a rich or lean mixture. It vaporizes
the fuel at the carburetor and eliminates the need ~or heat at the
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intake manifold. A lower temperature thermostat can thus be used
in the cooling system, permitting the use of cooler air for the
engine to provide an increased air-fuel ratio. This results in a
cleaner burning engine, fewer emissions, greater mileage and longer
engine life.
Modifications can obviously be made with respect to the
structural features specifically illustrated and described above.
For these reasons, only the following claims are intended to limit
and restrict the scope of the invention disclosed.
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