Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02327849 2000-12-07
FUEL VAPOR DELIYSRY SYSTEM FOR
ENGINES AND BURNERS
Field of the Invention
The invention relates to apparatus for providing
fuel vapors to engines, such as internal combustion engines
and jet engines, and to burners, for example burners for
heating furnaces, boilers and steam generators, for combus-
tion in said engines and burners.
B_ackaround of the Invention
Conventionally, most engines and burners employ
liquid hydrocarbon fuel, such as gasoline, kerosene, jet
fuel, fuel oil and diesel fuel, which is pumped or fed by
a conduit from the fuel tank to the engine or burner where
it is normally converted to a spray of fine droplets and
mixed with air for burning or igniting in the engine or
burner. In internal combustion engines, such as gasoline
and diesel engines, the fuel is converted to a fine spray
and is mixed with air by a carburetor or fuel injector or
similar device. In burners, the liquid fuel is typically
sprayed by a nozzle into a combustion chamber for burning.
The present invention provides a system for delivering to
the engine or burner fuel vapor produced by evaporation of
the fuel in a fuel tank rather than delivering liquid fuel
itself. The invention eliminates the need for a liquid
fuel delivery system and for conversion of the liquid fuel
to a fine spray of fuel droplets for combustion in the
engine or burner.
Summary of the Invention
In its most general form, the invention is an
apparatus for delivering fuel vapors to an engine or burner
for combustion therein. The apparatus comprises a fuel
tank for holding liquid fuel that can evaporate to produce
a combustible vapor, and a conduit from the fuel tank for
conducting the fuel vapors given off by the liquid fuel to
the engine or burner in which the vapor is combusted.
Preferably, the fuel tank is one in which there is
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headspace to hold the fuel vapors. Preferably, the appar-
atus also includes means for adding air to the fuel vapors
to form a mixture of fuel vapors and air. The apparatus
preferably includes a vapor reserve chamber between the
fuel tank and the engine or burner to hold a quantity of
fuel vapors.
In a preferred embodiment, the invention provides
an apparatus for delivering fuel vapors to an internal
combustion engine for powering the engine. The apparatus
has a fuel tank for holding liquid fuel, such as gasoline,
and has space to hold fuel vapors given off by the fuel.
The fuel tank has a port whereby the fuel vapors can exit
the tank. A conduit leads from this port to the intake
manifold for conducting the vapors to the engine. The
apparatus includes means for adding air to the fuel vapors
to form the mixture of fuel vapors and air that is ignited
in the combustion chambers of the engine. The apparatus
may include means for increasing the pressure of the fuel
vapors in the fuel tank. The apparatus can include a vapor
reserve chamber between the fuel vapor conduit and the
intake manifold for holding a quantity of fuel vapors. The
apparatus can also include a valve in the air intake tube
for preventing the fuel vapors from escaping when the
engine is not operating.
Brief Description of the Drawing's
Fig. 1 is a schematic illustration of a first
embodiment of the invention;
Fig. 2 is a schematic illustration of a second
embodiment of the invention; and
Figs. 3A and 38 are schematic illustrations of
embodiments of the invention which include the vapor
reserve chamber.
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Detailed Description of the Preferred Embodiments
The preferred embodiment of the invention
described and illustrated herein is the apparatus adapted
to deliver fuel vapor to an internal combustion gasoline
S engine.
Referring to Fig. 1, fuel tank 10 containing
gasoline 12 has a headspace 14 to hold gasoline vapors
which evaporate from the surface of the gasoline. An air
pump 16 communicates by a conduit 18 with the fuel tank.
The conduit 18 enters the fuel tank near its bottom so that
air pumped into the fuel tank is bubbled into the tank
through the gasoline. The air pump functions to add air to
the fuel vapors in the tank and to increase the pressure in
the headspace 14 in order to transport the fuel vapors in
the headspace to the engine, as described below. For
operation of the engine, the pressure in the headspace 14
is preferably in the range of 5-40 psi.
A port 20 is provided in the headspace area of
the tank 10, preferably in the top wall thereof, and a
conduit 22 leading to the engine 30 is affixed thereto.
The fuel tank 10 also has an inlet port (not
shown) for permitting the addition of gasoline to the tank.
Venting means are provided in conjunction with the inlet
port for venting pressure in the headspace to the atmos-
phere during refuelling, or to a separate vapor tank to
avoid release of the vapor into the atmosphere. Except
during refuelling, the fuel tank is preferably not vented
to the atmosphere.
The internal combustion engine 30 is conventional
in design apart from the absence of a carburetor. The
engine 30 has an intake manifold 32 which leads to the
combustion chambers (not shown) of the engine. A port 34
in the upper wall of the engine communicates with the
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intake manifold 32. The conduit 22 is affixed to the port
34 by a suitable fitting, permitting the flow of mixed air
and gasoline vapors from fuel tank 10, through the conduit
22, port 34 and into the intake manifold 32. The diameter
of the opening of conduit 22 into port 34 is preferably
about 1 mm, though this diameter can be larger or smaller
according to the type and size of the engine in which the
invention is used.
A metering valve 78 is provided in the conduit 22
which can be opened or closed to regulate the volume of
gasoline vapors per unit of time flowing into the engine.
Opening the metering valve 78 permits more vapors to flow
into the engine, thus accelerating the engine. Restricting
the flow of vapors by means of the valve decelerates the
engine. Metering valve 78 can be closed to stop all flow
in the conduit 22, thus stopping the engine.
In the embodiment of Fig. 1, conduit 18 leads to
the bottom part of the fuel tank 10 so air pumped into the
fuel tank by air pump 16 is bubbled through the gasoline.
This increases the formation of fuel vapors. Alternative-
ly, conduit 18 can lead directly into the headspace of the
fuel tank so air is not bubbled through the gasoline.
To operate the embodiment shown in Fig. 1, valve
78 is opened and the tank 10 is pressurized by means of air
pump 16, causing gasoline vapors to flow through conduit 22
and into the intake manifold. To start the engine, the
engine is cranked in the conventional manner, causing
gasoline vapor and air in the intake manifold to flow into
the combustion chambers and ignite and power the engine.
Fig. 2 illustrates a second embodiment of the
invention in which air to mix with the fuel vapors is
introduced directly into the intake manifold of the engine t
rather than into the fuel tank. In Fig. 2, numbered
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components correspond to like-numbered components of the
embodiment of Fig. 1. Conduit 22 leads from the headspace
14 of fuel tank 10 to the intake manifold 32 of the engine
30. An air inlet port 36 is provided in the intake mani-
fold 32 and air inlet tube 38, having open upper end 40, is
affixed thereto. Air flows from the atmosphere into the
intake manifold through the air inlet tube 38 and mixes in
the intake manifold with fuel vapors received through
conduit 32. The air is drawn into the manifold through
inlet tube 38 by the suction created by the intake stroke
of the pistons. A flutter valve (not shown), which may be
controlled by an operator, is provided in the upper end of
tube 38. The valve opens to permit air to flow into tube
38 from the atmosphere, and closes tube 38 to prevent
gasoline vapors from escaping out of tube 38 when the
engine is shut off. An air filter (not shown) may also be
provided on top of tube 3~ for filtering incoming air.
In the embodiment of Fig. 2 a pressurizes, for
example an air pump which pumps air into the fuel tank 10,
can be provided if desired to increase the pressure in the
headspace of the fuel tank in order to increase the flow of
fuel vapors through conduit 22 to the engine.
To operate the embodiment shown in Fig. 2,
metering valve 78 is opened and the engine is cranked in
the conventional manner. Fuel vapors flow to the intake
manifold through conduit 22 and air is drawn into the
intake manifold through air intake tube 40. The gasoline
vapors and air in the intake manifold flow into the combus-
tion chambers and ignite and power the engine.
Referring next to Figs. 3A and 3B, in which
numbered components correspond to like-numbered components
shown in Figs. 1 and 2, there is shown the optional fuel
vapor reserve chamber 60 affixed to the outside of the
outer wall of the intake manifold. Chamber 60 serves as a
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storage chamber to hold a quantity of vaporized fuel and
air for immediate use when the engine is started or accel-
erated. Port 34' is provided in the upper surface of
chamber 60, and conduit 22 is connected thereto. Chamber
60 opens into intake manifold 32 through port 62 in the
outer wall of the intake manifold.
Fig. 3A illustrates the vapor reserve chamber in
the embodiment of Fig. 1, in which there is no separate air
inlet port in the engine. Here, the mixture of air and
fuel vapor flowing through conduit 22 is stored in chamber
60. Fig. 3B shows the fuel vapor reserve chamber 60 with
a separate air inlet port 36' and air inlet tube 38. Air
is drawn into the vapor reserve chamber from the atmosphere
through tube 38 by the intake stroke of the pistons, and
mixed with fuel vapors from conduit 22. The mixture is
drawn into the intake manifold through port 62. As in the
embodiment of Fig. 2, a flutter valve (not shown), which
may be controlled by an operator, is provided at the upper
end of tube 40 to prevent the escape of gasoline vapors,
and an air filter (not shown) may be provided to filter air
entering the engine through tube 40.
Optionally, each of the embodiments can include
means far heating the fuel in the fuel tank, or for heating
the fuel vapors before they enter the engine. The appar-
atus can also include an agitator in the fuel tank for
mixing the fuel and air or fuel vapor in order to increase
the production of fuel vapor. The vapor reserve chamber
may be heated to prevent condensation of fuel vapors
therein.
As will be apparent to those skilled in the art
in the light of the foregoing disclosure, many alterations
and modifications are possible in the practice of this
invention without departing from the spirit or scope
thereof. The apparatus can be used for any engine or
CA 02327849 2000-12-07
burner that uses fuel which can be vaporized in the fuel
tank and the vapors transported by a conduit to the engine
or burner. A single fuel tank or multiple fuel tanks can
be employed. A single or multiple vapor reserve chambers
can also be employed and can be positioned at various
points between the fuel tank and the engine or burner along
the fuel vapor conduit. Multiple vapor lines can be
provided between the fuel tank and the vapor reserve
chamber and between the vapor reserve chamber and the
engine or burner. A pump to assist the flow of fuel vapor
through the conduit by means of suction can be provided.
The fuel tank may have a conical upper portion, with a
vapor outlet port at the top thereof. The fuel tank can
either be provided with a headspace for accumulation of
fuel vapor or the vapor can be transported directly to the
engine or burner, or can be removed from the fuel tank and
accumulated in a vapor reserve chamber. Engines in accord-
ance with the invention can have a single intake manifold
or can have multiple intake manifolds, each of which is
provided with a fuel vapor conduit. The fuel used in
engines and burners employing the invention can include
gasoline, diesel oil, airplane fuel, fuel oil and any other
liquid fuel conventionally used in the type of engine or
burner in which the invention is employed. The apparatus
can be used in engines for land vehicles, such as cars,
trucks, trains and buses, in water vessels of any kind and
in flying craft, such as aircraft and hot air balloons, as
well as in stationary or moveable engines or equipment. It
can also be used in burners, such as burners for furnaces
and water boilers. The scope of the invention is to be
construed in accordance with the substance defined by the
following claims.
