Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a means for delivering
a fuel to an engine More particularly, it relates to a
delivery assembly for dispersing a supplemental fuel with 'eke
air intake of a diesel engine.
t is known to the prior art to supplement the
primary fuel for a diesel engine with a supplemental petroleum
gas, such as propane. The supplemental fuel is directed into
the air intake channel of the engine. Propane raises the
combustion temperature within the cylinders of the engine and,
within the operating limits ox the engine, can significantly
increase the efficiency of the engine. For a given amount
of diesel fuel, a small amount of propane or other petroleum
gas can increase the power output ox a diesel engine by up
to approximately 15% without significantly altering the
operating characteristics or the operating life of the engine.
another benefit of introducing a supplemental petroleum gas
into the air intake ox a diesel engine is the reduced number
of combustion by-products in the engine exhaust gases, which
reduction results directly from the higher operating temperature
within the piston cylinders. This invention relates more
particularly to propane because of the ready availability
ox likelihood propane, although one skilled in the art could
readily adapt the injector of this invention to similar
petroleum products.
Clarence D. Fox in his Canadian Patent Nos. 839,005
and 887,976, granted on April Thea, 1970 and December Thea,
1971, respectively, discloses systems for introducing a
supplemental fuel (a petroleum product) into the air intake
channel ox a diesel engine. As the disclosure ox Canadian
Patent No. 839,005 indicates, attempts have been made to
provide a throttle-controlled metering valve in the air intake
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channel of a diesel engine to admit the supplemental fuel
proportionately with respect to the throttle position. That
patent indicates that the throttle-control metering valves
were both difficult to install and to regulate by the operator.
That patent also discloses a means for metering the introduction
of the supplemental fuel into the air intake of the diesel
engine by means of a temperature sensor located in the exhaust
manifold of the engine. An increased engine load results in
an increase in the temperature of the exhaust gases from the
lo engine, and an electrical circuit is activated which operates
a solenoid valve which in turn activates a pressure regulator
to release supplemental fuel into the air intake channel of
the engine. When the engine load drops, the temperature of
the exhaust gases from the engine drop which temperature
decreases are sensed by the sensor in the exhaust manifold and
relayed to the pressure regulator which stops the flow of
supplemental fuel into the engine. The supplemental fuel
system outlined in Canadian Patent No. 887,976 operates on
a similar feedback system.
The inventors of the subject invention have found
that a significant drawback of the systems disclosed in
Canadian Patent Nos. 839,005 and ~87,976 is that the temperature
sensor in the exhaust manifold of a diesel engine often
corrodes or is destroyed by the high temperature of the exhaust
gases. Also, such a feedback system is not well suited for
the operation of a diesel engine. The speed of rotation and
thus the power of a diesel engine is controlled by the rate
of injection of diesel fuel into the engine cylinders. As
the rate of diesel fuel injection into the cylinders is
increased, the rate of air inflow into the cylinders is also
increased. us Canadian Patent No. 839,005 indicates, the most
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desirable way of controlling the rate of flow of the supplemental
fuel into the engine is by a means in which the supplemental
fuel flow increases with the increase of air drawn into the
engine. There are several advantages to a supplemental fuel
system for a diesel engine in which the supplemental fuel is
drawn into the engine in proportion to the inflow of air. One
advantage is that a feedback system dependent on exhaust gas
temperature with associated time delays, is not required
Another advantage is that the resultant increase in engine
power is proportional to the increased rate of supplemental
fuel flow. As an operator increases the rat of flow of diesel
fuel into the cylinders of the engine, the air inflow to the
engine increases. As supplemental fuel flows into the engine
with tile increase in air inflow, the combustion temperature
within the cylinders increases beyond the normal combustion
temperature of diesel fuel, resulting in a higher power output
Han would result from consumption of diesel fuel alone. The
introduction of a supplemental fuel such as propane into
the cylinders of a diesel engine results in more efficient
combustion of the diesel fuel, and the energy provided by
the combustion of a mixture such as diesel fuel and propane
is greater than the total energy produced when they individually
undergo combustion
The subject invention relates not only to a means
for varying supplemental fuel flow according to the rate of
air inflow to an engine, but also relates to a means for
adeptly mixing the supplemental fuel with the air inflow
prior to the gas mixture entering the combustion cylinders.
It the supplemental fuel and the air are not adequately mixed
prior to entering the combustion cylinders, the composition of
the gas mixture entering the cylinders may vary from cylinder
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to cylinder, resulting in combustion temperature variation
between the cylinders which can result in engine vibration.
The subject invention provides better mixing of the supplemental
fuel with the air and also a supplemental fuel flow rate varying
proportionately with the rate of air indeed, by utilizing a gas
flow delivery tube which extends across the air flow of the air
intake channel of the diesel engine for the approximate width
of the channel. This gas flow delivery tube passes through and
is secured to a wall of the air intake channel. A flow control
valve, which is attached to the end of the gas flow deliver
tube exterior to the air intake channel, controls the maximum
rate of flow of gaseous supplemental fuel through the tube.
Apertures in the tube allow supplemental fuel gusto flow
from the interior of the tube to the interior of the air intake
channel. This results in dispersion of the gaseous supplemental
fuel entering the air intake channel with the air flow through
that channel. The gas flow delivery tube and flow control
valve are hereinafter referred to as a delivery assembly.
In another form of the invention the gas flow delivery
I tube is of circular cross section. In yet another form of
the invention, the apertures in the gas flow delivery tube are
directed towards the downstream side of the air intake channel.
on a further form of the invention, the apertures are a series
of orifices, evenly spaced along the length of the gas flow
delivery tube. The supplemental fuel is propane or a similar
petroleum product.
A further form of the invention is a supplemental
fuel system for a diesel engine comprising a storage tank,
a heat exchanger, a fuel release valve, and a delivery assembly
a previously described and comprising a gas flow delivery tube
and an associated flow control valve. The tank stores the
fuel in the liquid state and has an outlet connected to a
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heat exchanger. The heat exchanger vaporizes fuel leaving
the tank and has connected to its outlet a fuel release valve.
The fuel release valve is connected to the inlet of the
delivery assembly and releases the gaseous fuel to the inlet
of the delivery assembly at a rate proportional to the
pressure at that inlet.
The subject invention and its advantages will
become more apparent when reference is made to the accompanying
drawings and the preferred embodiment which relates thereto.
Figure 1 is a side view of a truck with the subject
invention installed therein.
Figure 2 is a perspective view of the engine compartment
of a truck prior to installation of the subject invention.
Figure 3 is a perspective view of the engine
compartment of Figure 2 but with the subject invention installed
therein.
Figure is a partially sectioned view of the
air intake pipe of Figure 3 illustrating insertion of the
supplemental fuel into the air stream.
Figure S is a detailed side view of a part of the
apparatus of the subject invention disclosed in Figure 3.
The preferred embodiment of the subject invention
utilizes propane fuel which, because of its utilization in
motor homes and Sumner cottages, has always been readily
accessible at a number of convenient outlets. The truck of
Figure 1 has a liquid propane storage tank 11 affixed to the
frame rearward of the cab and forward of the back wheels. The
tank has a 50 gallon capacity, and a sister tank can be mounted
to the other side of the frame if greater capacity is required.
A valve 12 mounted on tank 11 meters the flow of liquid propane
out of the tank and into propane fuel line 13; typically, in
warm weather the pressure in tank 11 and supply line 13 are
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Lowe
over 100 pounds per square inch (190 pi at 100F),
although such pressure may decrease dramatically during cold
weather. Supply line 13 extends under cab 14 and along main
frame beam 15 to the engine compartment of the truck.
Figure 2 illustrates the engine compartment of the
truck prior to the installation of the equipment of the subject
invention. only those engine components which are essential
to an understanding of the invention are illustrated in Figure 2;
it should be obvious, however, to any person skilled in the
art that the engine compartment of a large truck holds a great
number of components related to proper operation of the engine.
Figure 2 simply illustrates in the engine compartment an engine
20 having a cooling fluid inflow pipe 21 and a cooling fluid
outflow pipe 22, the pipes transporting cooling fluid between
the engine and the radiator 23 (see Fig. 3) of the truck A turbo-
charger 25 receives air from a location external to the engine
compartment through an air inlet pipe 26 constructed from
galvanized steel and a rigid plastic such as polyvinyl chloride,
on sir filter 27 is mounted to the truck body 28 to extend
over the external end of air inlet pipe 26.
Figures 3, 4 and 5 illustrate those components of the
propane power boosting apparatus that are situated in the engine
compartment. A platform 30 is supported to sit above engine
20 by a pair of angle irons 31 each welded to platform 30 and
to a respective side of the body 28 of the truck. Mounted to
platform 30 are a lock-off valve 33 and a vaporizing heat
exchanger I Liquid propane line 13 which has one end
connected to storage tank 11 and extends under cab 14 of the
truck has its other end connected to lock-off valve 33. Lock-
off valve 33 includes an electrically-operated solenoid actuated
by means of a switch in the cab of the truck. When valve 33
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is actuated, liquid propane passes through the valve and
into flow line 35 which connects valve 33 to vaporizing heat
exchanger 34.
Vaporizing heat exchanger 34 is regulated such that
propane entering it through flow line 35 as a high pressure
liquid is vaporized and leaves it through flow line 36 as a
gas at approximately atmospheric pressure. Heat to vaporize
the propane is provided by flowing the engine-heated cooling
fluid through heat exchanger 34. A tee is placed into each
of the engine cooling fluid hoses near their point of connection
with the engine. A hose 37 connected to the tee in outflow
cooling fluid hose 22 connects at its other end to a port in
heat exchanger 34~ Similarly, a second hose 38 connects a
second port on heat exchanger 34 to the tee placed in inflow
cooling fluid hose 21. The tees in hoses 21 and 22 are labeled
39 and 40, respectively, in Figure 3. Hoses 37 and 38, which
are capable of withstanding the pressure of the cooling fluid,
ax connected to heat exchanger 34 such that hose 37 carries
heated cooling fluid into the heat exchanger and hose 38
rural that cooling fluid after extraction of heat therefrom.
The proportion of cooling fluid passed through heat exchanger
34 it small compared to the amount of cooling fluid passed
through radiator 23. The "Model J" vaporizer of Impco
Corroboration, Inc. of Sorts, California, is a device suitable
as a heat exchanger in the subject invention. The "Model J"
vaporizer has a built-in regulator which limits the pressure
ox the propane gas leaving the vaporizer; for the subject
invention, the regulator is adjusted so that at its outlet
the pressure of the propane gas is approximately atmospheric.
The Century Company of Paramount, California is one manufacturer
of a suitable lock off valve.
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Heat from the engine 16 cooling fluid may not be
required for vaporizing the propane in warm weather conditions.
It will, however, be of great importance during cold weather
conditions when the ambient air cannot supply sufficient heat
to vaporize the liquid propane. It is recommended, therefore,
that heat exchanger 34 be connected at all times to the engine's
cooling system.
Flow line 36 carries propane gas from exchanger 34
to an injector assembly 40 secured to air inlet pipe 26.
Delivery assembly 40 comprises a flow control valve 41, a
gas flow delivery tube 42 connected to valve 41, and a flange
43 for mounting the assembly on the air inlet pipe 26. Gas
flow delivers tube 42 is connected to flow control valve 41 such
that adjustment screw 44 regulates the amount of propane gas
which flows from flow line 36 to delivery tube 42. The
slow passage between delivery tube 42 and control valve 41
intersects the threaded bore along which adjustment screw 44
travels. Adjustment screw 44 may be turned so as to completely
cover that slow passage and prevent passage of the gas into
delivery tube 42 or screw 44 may be turned to allow full or
partial flow of the gas through the flow passage.
Delivery tube 42 extends diametrically across
air inlet pipe 26 such that its closed outer end maintains
close spaced relation with air inlet pipe 26. Thy size of
delivery tube I is thus dependent upon the size of the air
inlet pipe in which it sits, which in turn is dependent
upon the horsepower of the engine. To allow for its
lady adaptation to various diameter sizes of air inlet
pipe, delivery tube 42 is formed from copper tubing cut to
length with a cap placed over its outer end. Prior to its
so
placement into air inlet pipe 26, delivery tub 42 has holes
drilled therein so as to face downstream in air inlet pipe
26 when delivery assembly 40 is installed. The diameter
of delivery tube 42 and the size and spacing of the series
of holes drilled therein are a function of the engine horse-
power, and the following chart indicates the tube diameter,
hole size and hole spacing to be selected:
Engine Horse Delivery
Power Tube Diameter Hole Sicily Spacing
.
1050 - 1001/4 inch No. 34 drill size 1/2 inch
100 - 2003/8 inch No. 27 drill size 1/2 inch
200 - 3501/2 inch No. 20 drill size 3/4 inch
350 - 5003/4 inch No. 11 drill size 1 inch
500 - 10001 1/2 inch No. 1 drill size 1 inch
The foregoing table assumes that the diameter of the
air inlet pipe 26 varies generally with the engine horsepower
i.e. the 1/4 inch diameter tube used with a 50 horsepower
engine would only be approximately 2 inches long while the
1 1/2 inch tube required with a 1,000 horsepower engine might
be 12 inches long or even longer. It is recommended that
the delivery tube length should be no longer than as
indicated by the following chart:
Delivery Delivery Tube
Tube Diameter Maximum Length
1/4 inch 2 inches
3/8 inch 3 inches
1/2 inch 6 inches
3/4 inch 10 inches
1 1/2 inch 16 inches
I
The Impco vaporizer 34 maintains the propane gas
in flow line 36 at approximately atmospheric pressure, and that
pressure does not vary with adjustment ox screw 44. With
airflow through air inlet pipe 26, a sub-atmospheric pressure
is created at the holes facing downstream in delivery tube 42.
Propane gas at atmospheric pressure in flow line 36 attempts
to pass into the sub-atmopsheric interior of delivery tube
42, such passage being metered by rotation of screw 44.
The holes in delivery tube 42 are equally spaced
across the diameter fair inlet 26 which provides excellent
mixing of the air and propane prior to their entry into turbo-
charger 25.
The subject invention is very easily installed on
existing trucks, and with modifications, could be installed
in automobiles. Most trucks would have sufficient room for
placement ox a platform 30 above the engine, platform 30 being
rigidly connected to the frame 28 of the truck by a pair of
angle irons 31. Tank 11 can be fastened by steel bands to the
main frame beam, and fuel line 30 extended under the cab of the
truck into the engine compartment. An Impco vaporizer and
Century lock-off valve can be bolted to platform 30 as previously
described. Fuel line 13 is then fastened to the inlet port
of lock-off valve 33, and a flow line 35 is connected between
the outlet port of lock-off valve 33 and the inlet gas port
of vaporizer 34. A pair of tees are then placed into the hoses
carrying cooling fluid between the engine and the radiator, and
a hose is connected from each tee to the vaporizer.
With the engine switched off and air inlet pipe 26
di~aonrlected from turbocharger 25 a hole is cut or drilled
into air inlet pipe 26 at least 12 inches upstream from its
end. The hole is sufficiently large that delivery tube 42 can
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fit there through. Screws are then inserted through flange 43
to secure delivery assembly 40 to air inlet pipe 26. Prior
to insertion of delivery tube 42 into air inlet pipe 26,
the delivery tube would have been sized and the holes drilled
therein according to the criteria previously described.
Flow line 36 is then connected between the gas outlet port
of vaporizer 34 and delivery assembly 40. Wires are connected
from liquefy valve 33 to a toggle switch in the cab of the
truck and to a battery connection, such electrical wiring being
familiar to one skilled in the art.
Tank 11 is then filled with liquid propane and, with
liquefy valve 33 closed, valve 12 on tank 11 is opened.
Inspection is made of flow line 13 for leakage. Lock-off valve
33 is then opened, and the pressure regulator on vaporizer
34 is adjusted such that sufficient pressure exists in flow
line 36 and the interior of delivery tube 42 to blow out any
material that may have become lodged therein. Vaporizer 34
is then adjusted such that the pressure ion flow line 36 with
screw I in the closed position is atmospheric. Lock-off
I valve 33 is then closed. After ensuring that any loose material
has been removed from air inlet pipe 26, that pipe is then
reattached to turbocharger 25.
It is important to note that the subject invention
should not be connected to an engine with a lifetime of less
than 100 hours. the engine should have had time to adjust to
a smooth, normal operating condition. After the equipment
has been installed on the truck, the propane flow must be
calibrated. Preferably, a dynamometers is connected to the
engine and a pyrometer is utilized to measure exhaust tempera-
lure. The engine is throttled wide open and screw 44 is turned slowly outward until the maximum horse power of the
85~3S~
engine has increased from 5% to 15~ (according to owner's
wishes). A lock nut can be screwed onto screw 44 at that
position to ensure that vibration does not cause it to rotate
further. Exhaust temperature should be monitored very closely
to ensure that the maximum rated operating temperature for
the engine is not exceeded.
It is common for owners of diesel trucks to modify
the diesel oil pump such that it pumps at a faster rate than
called for by the factory specification. Prior to installation
of the subject invention on a truck with that modification,
the diesel pump must be set back to pump at the factory
specification or, preferably, 5 to 10% below the factory
specification. The propane gas requires a proper amount of
air for combustion, and a fuel mixture rich in diesel oil
does not allow the requisite complete combustion of the
propane. As an example, when propane is added to the air
intake such thought Tulsa improvement is realized over the
diesel only power rating (it is not advisable to increase
power more than 15%), the rate of diesel oil consumption
is approximately 20% less than was consumed at the maximum
diesel-only power level. The saving in diesel oil consumption
results in a great cost saving since the dollar-value of
propane consumed is much less than the dollar-value of diesel
oil saved.
An engine to which the subject invention is fitted
should be in optimum condition. In an older engine the piston
rings may be loose and the compression decreased; similarly,
with valve springs, the fuel pump, and injector tips. The
engine should be examined prior to installation of the subject
invention to ensure that it is otherwise in optimum condition
and will obtain the maximum Bennett from the invention.
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