Apparatus for mixing gaseous fuel with air

A system and method for mixing gaseous fuel with air prior to combustion in an internal combustion engine. The system includes an L-shaped channel with a cap mounted to one end and an inlet formed at the other end. A plurality of holes is formed in the L-shaped channel. The channel is mounted to the air intake system of the internal combustion engine upstream from the air filter such that a partial vacuum is created in the vicinity of the holes as the incoming air flows past the channel. The channel includes means for regulating the flow of gaseous fuel through the channel.

BACKGROUND 
1. Field of the Invention 
The present invention relates to a system and method for mixing gaseous 
fuel with air, and more particularly, to a system and method for mixing 
gaseous fuel with air in a dual fuel system of an internal combustion 
engine. 
2. Prior Art 
Various types of carburetors have been developed for internal combustion 
engines to solve the basic problem of mixing liquid gasoline fuel with air 
to provide a combustible fuel/air mixture. Problems inherent in the 
carburetion of liquid fuels have led many to explore gaseous fuels, such 
as propane, as an alternative to conventional gasoline or diesel fuels. 
Thus, many different carburetors or mixers have been developed for gaseous 
fuel systems. 
Much development has occurred particularly in the area of "conversion kits" 
for gaseous fuel mixers which are adapted for installation in the gasoline 
fuel carburetion system of an ordinary internal combustion engine. These 
so-called conversion kits are intended to provide a dual fuel system which 
will permit operation of the engine on liquid fuel alone, gaseous fuel 
alone, and in some systems, combinations of the two fuels. 
The prior art gaseous fuel mixers can be generally classified ito three 
categories based on the type of installation within the combustion engine: 
(1) mixers which are installed between the intake manifold and the 
carburetor; (2) mixers which are installed directly inside of or around 
the carburetor; and (3) mixers which are installed within or adjacent the 
air filter housing so as to release gaseous fuel inside the air filter. 
Generally speaking, each of these types of gaseous fuel mixers is difficult 
to install. The desired connections are often congested with throttle 
linkage, choke linkage, vacuum hoses, fuel lines, valve lines, and the 
like. Moreover, typically the prior art fuel mixers require complicated 
adjustments in order to adapt them to the characteristics of a particular 
combustion engine. 
Another common installation problem is that portions of the original engine 
equipment must be replaced or modified to accommodate installation of the 
prior art type mixers. As a result, time-consuming modifications must be 
made to the engine. For example, often it ocurs that a gaseous fuel mixer 
cannot be used with the existing air intake system of the combustion 
engine. This necessitates providing the mixer with a vacuum-creating 
device or pressurizing the gaseous fuel before injection into the air flow 
to obtain an adequate fuel/air mixture. Also, prior art fuel mixers of the 
third type, those releasing gaseous fuel inside the air filter, are 
commonly connected to a gaseous fuel line through the top of the air 
filter housing. Such fuel line connections frequently require modification 
of the car hood to accommodate the gaseous fuel lines. 
Another significant problem experienced with the prior art type fuel mixers 
is that proper mixing of the gaseous fuel with the air flowing into the 
combustion engine is difficult to achieve. The basic problem is how to 
combine the fuel and air particles into a homogeneous mixture. An 
important factor in achieving a homogeneous mixture of fuel and air is the 
path of the air flow in relation to the entry of the gaseous fuel into the 
air flow. In nearly every internal combustion engine, the air flow is 
irregular between the air filter and the engine cylinders, and since most 
prior art fuel mixers use the existing air flow system of the internal 
combustion engine, some of the engine cylinders receive a richer gaseous 
fuel/air mixture than other cylinders. Thus, to compensate, the rate of 
gaseous fuel injection into the air flow is increased so that combustion 
will still occur within the cylinders receiving the leanest air/fuel 
mixture. By adjusting the rate of fuel flow to provide the leanest 
cylinder with an optimum air/fuel mixture, the other cylinders 
consequently receive a richer air/fuel mixture than is necessary for 
combustion, resulting in wasted fuel and poor engine efficiency. This 
problem is compounded by the fact that in many cases, the very 
installation of the prior art type gaseous fuel mixers tends to render the 
incoming air flow more irregular. 
A further problem of nearly every prior art type mixer is that additional 
gaseous fuel is wasted during acceleration of the engine due to the effect 
of the engine vacuum during the air response delay between the engine 
cylinders and the air inlet of the air intake system. Typically, when a 
driver depresses the accelerator pedal of his vehicle to accelerate the 
engine, a series of butterfly valves in the carburetor are opened to allow 
more fuel/air mixture to enter the cylinders, thus increasing the power 
output of the engine. Upon opening these valves, the air flow within and 
immediately around the carburetor is suddenly exposed to a vacuum created 
by the engine pistons. The influence of the vacuum is transferred back 
through the engine's air flow system until satisfied by the incoming air 
that is drawn through the air intake. With the prior art type mixers, this 
momentary vacuum imposed on the prior art type mixers causes additional 
fuel to exit the fuel mixing device and mix with the air flow, thus 
yielding a gaseous fuel/air mixture which is considerably richer than the 
optimum mixture needed for combustion. As a result, the excess gaseous 
fuel injected into the air flow is wasted. And when the air filter of the 
internal combustion engine is dirty or becomes wet, the air flow is 
further impeded and even more gaseous fuel is wasted due to a longer air 
response delay during acceleration. 
In view of the foregoing, what is needed in the art is a gaseous fuel mixer 
for a dual fuel system of an internal combustion engine that overcomes 
these and other problems of the prior art, and yet is economical and 
simple to construct and install. 
BRIEF SUMMARY AND OBJECTS OF THE INVENTION 
The present invention relates to a system and method for mixing gaseous 
fuel with air for subsequent combustion in a dual fuel combustion engine. 
The gaseous fuel mixer includes a channel with a cap mounted to one end 
and an inlet formed at the other end thereof. The gaseous fuel mixer is 
mounted to the air intake system of an ordinary internal combustion engine 
at a position before the air filter. The cap is positioned outside the air 
intake system so as to support the channel within the air intake system. 
The inlet is connected to a fuel line which is in communication with a 
gaseous fuel source. 
The fuel line introduces gaseous fuel into the inlet at atmospheric 
pressure. A series of holes is formed in a portion of the channel and is 
situated within the air intake system so as to point downstream from the 
air flowing through the air intake system. As incoming air rushes past the 
holes formed in the channel, a partial vacuum is created near the holes, 
drawing the gaseous fuel from the channel into the air intake system. As 
the rate of air flow through the air intake system increases, the amount 
of gaseous fuel drawn through the holes into the air intake system 
increases proportionately. Thus, the ratio of gaseous fuel to air within 
the air intake system always remains essentially constant. An adjustable 
flow regulator mounted to the channel allows the user to adjust the flow 
of gaseous fuel into the channel. 
It is, therefore, an object of the present invention to provide a gaseous 
fuel mixing system for mixing propane or other gaseous fuel in a dual fuel 
system of an internal combustion engine. 
It is another object of the present invention to provide a gaseous fuel 
mixer which is quickly and easily installed into the air intake system of 
an internal combustion engine without elaborate modification of the 
existing engine system or cumbersome and time-consuming installation 
procedures. 
Still another object of the present invention is to provide a gaseous fuel 
mixer which is inexpensive and of simple construction, requiring no 
precision machining in the manufacture thereof, and which is thus 
inexpensive and yet highly effective in achieving its intended result. 
A further object of the present invention is to provide a gaseous fuel 
mixing system which achieves nearly perfect mixing of the gaseous fuel 
with air before the gaseous fuel/air mixture reaches the cylinders of the 
internal combustion engine. 
Yet another object of the present invention is to provide a gaseous fuel 
mixing system which provides a constant gaseous fuel/air ratio 
irrespective of increased impedance to the air flow caused by the air 
filter and the cylinders of the engine system. 
Still another important object of the present invention is to provide a 
gaseous fuel mixing system which achieves high fuel economy during the 
operation thereof. 
Yet a further object of the present invention is to provide a highly 
effective method for mixing gaseous fuel with air in a dual fuel system of 
an internal combustion engine. 
These and other objects and features of the present invention will become 
more fully apparent from the following description and appended claims 
taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
Reference is now made to the figures wherein like parts are designated by 
like numerals throughout. 
A first preferred embodiment of the gaseous fuel mixer of the system of the 
present invention, generally designated 10, is illustrated in FIG. 1. The 
gaseous fuel mixer 10 includes a hollow L-shaped channel which is formed 
by connecting a first channel member 16 to a second channel member 12. 
Channel member 12 is attached to channel member 16 by a series of threads 
30 formed in the lower end of channel member 12. A cap 14 is mounted to 
the upper end of channel member 12 by glue, epoxy, or other suitable 
means. First channel member 16, second channel member 12, and cap 14 can 
be formed from any material which is resistant to corrosion by the gaseous 
fuel, as for example, polyvinyl chloride (PVC), fiberglass, plastics, 
certain types of metals, ceramics, or epoxies. 
A plurality of holes 18 are formed in the second channel member 12 as shown 
in FIG. 1. Holes 18 can be arranged in any desirable pattern; however, it 
has been found advantageous to arrange holes 18 in a single row so as to 
be diametrally opposite the surface of second channel member 12 which is 
first contacted by the air flow, as will be explained in more detail 
herein. 
A gaseous fuel inlet 22 is formed in one end of first channel member 16. A 
series of ridges 20 is also formed near the end of first channel member 16 
to provide an anchoring surface for a gaseous fuel line to be attached 
thereto. 
An adjustable screw 24 is used to regulate the flow of gaseous fuel through 
first channel member 16, and subsequently, through second channel member 
12. Adjustable screw 24 has a series of threads 28 for connection to the 
first channel member 16. A nut 26 is used to secure screw 24 to first 
channel member 16 at any desirable position. By adjusting the screw 24 the 
impedance within first channel member 16 may be increased or decreased so 
that the rate of gaseous fuel flowing through first channel member 16 can 
be correspondingly increases or decreased, thus regulating the flow of 
gaseous fuel through second channel member 12 and out holes 18. 
A second preferred embodiment of the gaseous fuel mixer of the system of 
the present invention, generally designated 11, is illustrated in FIG. 2. 
This embodiment is identical to the embodiment of FIG. 1 except that the 
embodiment of FIG. 2 includes a plurality of rectangular holes or slits 
18a formed in the second channel member 12. Slits 18a are illustrative of 
the various configurations which can be used to form the outlet in second 
channel member 12. Other suitable configurations could also be used, as 
for example, a continuous slit (not shown) extending the length of the 
area covered by slits 18a in FIG. 2. Thus, it will be appreciated that any 
number of configurations are possible in forming one or more outlets in 
second channel member 12 in implementing the inventive concepts of the 
present invention. 
A third preferred embodiment of the gaseous fuel mixer of the system of the 
present invention, generally designated 13, is shown in FIG. 3. This 
preferred embodiment is also identical to the embodiment of FIG. 1 except 
that instead of an adjustable screw 24 and position-fixing nut 26 to 
regulate the flow of gaseous fuel through first channel member 16, the 
embodiment of FIG. 3 includes a stopcock generally designated 31 to 
regulate the flow of gaseous fuel through first channel member 16. 
Stopcock 31 comprises a handle 32 and a rotatable member 34 having a bore 
36 formed therein. Stopcock 31 is mounted to first channel member 16 such 
that stopcock handle 32 is disposed outside channel member 16 and 
rotatable member 34 is disposed within channel member 16. The diameter of 
rotatable member 34 corresponds to the diameter of first channel member 
16. By turning stopcock handle 32, bore 36 can be positioned to increase 
or decrease the rate of gaseous fuel flowing through the first channel 
member 16, and subsequently through the second channel member 12. Maximum 
fuel flow is achieved by positioning bore 36 parallel with the walls of 
first channel member 16. Minimum fuel flows, or effectively no fuel flow, 
is accomplished by positioning bore 36 perpendicular to the walls of first 
channel member 16. 
It will be appreciated that various other flow-regulating devices may be 
used in lieu of adjustable screw 24 of FIG. 1 or stopcock of FIG. 3. 
The installation of the gaseous fuel mixer in the air intake system of an 
internal combustion engine is best viewed in FIG. 4. Although the gaseous 
fuel mixer illustrated in FIG. 4 corresponds to the embodiment of FIG. 3, 
the preferred embodiments of FIGS. 1 and 2 would be installed into the air 
intake system in an identical manner. The gaseous fuel mixer 13 is mounted 
to a snorkel 15 which is formed as an extension of an air filter housing 
40 of the air intake system. Air filter housing 40 represents the air 
filter housing of any ordinary vehicle and has a lid 41 secured to the top 
thereof by a wing nut 43 as well as an air filter 42 disposed within the 
housing 40. Similarly, snorkel 15 represents the snorkel of any ordinary 
vehicle and has an inlet 17 for receiving incoming air. 
Referring still to FIG. 4, the gaseous fuel mixer is installed into the air 
intake system by first drilling holes through the top and bottom surfaces 
of snorkel 15 which correspond to the diameter of second channel member 
12. Cap 14 is mounted to second channel member 12 and the cap/channel 
member assembly is inserted into the top hole of snorkel 15 such that 
holes 18 face directly opposite snorkel inlet 17. First channel member 16 
is screwed onto the end of second channel member 12 at threads 30 and 
positioned against the bottom surface of snorkel 15 to cooperate with cap 
14 in securing second channel member 12 within the snorkel 15. It may also 
be desirable to apply a silicone compound around the base of cap 14 and 
first channel member 16 to provide a leakproof seal between the gaseous 
fuel mixer and snorkel 15. A gaseous fuel line 38 is inserted over the end 
of first channel member 16 and is secured in place by the ridges 20 formed 
at the end of first channel member 16. Gaseous fuel line 38 is 
additionally secured to first channel member 16 by a conventional screw 
clamp 37. 
Referring now to FIG. 5, the gaseous fuel mixer can be installed anywhere 
along the air intake conduit, generally designated 62, of the air intake 
system. The air intake conduit 62 includes snorkel 15 and a ram induction 
conduit 66 terminating at an air inlet 64. Ram induction conduit 66 is 
connected to snorkel 15 at snorkel inlet 17 so that air entering air inlet 
64 passes through ram induction conduit 66, into snorkel 15, and 
subsequently into air filter housing 40. 
The various possible installation positions for the gaseous fuel mixer are 
illustrated in FIG. 5 by the position of the cap 14 and alternative cap 
positions 14a-14g shown by dashed lines. Alternative cap position 14a 
represents positioning of the gaseous fuel mixer just inside air filter 
housing 40 but still before the air filter 42 shown in dashed lines. 
Alternative cap positions 14b, 14c, and 14d represent alternative 
positioning of the gaseous fuel mixer within snorkel 5. Alternative cap 
positions 14e, 14f, and 14g represent alternative positioning of the 
gaseous fuel mixer within the ram induction conduit 66. It will thus be 
apparent that the gaseous fuel mixer may be mounted to the air intake 
system at any position from air inlet 64 to air filter 42. The internal 
combustion engine 58 and vehicle body 60 are included to illustrate the 
environment of the system of the present invention. 
One presently preferred method of using the gaseous fuel mixer is also 
understood by reference to FIG. 4. FIG. 4 schematically illustrates the 
dual fuel system for the internal combustion engine 58. The liquid 
gasoline fuel system and the gaseus fuel system can be used alone or in 
combination to operate the internal combustion engine 58. 
The liquid gasoline fuel system illustrated in FIG. 4 is typical of the 
type of gasoline fuel systems used in most internal combustion engines. A 
gasoline carburetor 44 communicates with air filter housing 40 to receive 
incoming air after filtration by air filter 42. A plurality of venturies 
46 are formed within carburetor 44 and provide passageways for the air 
which will be directed to each of the engine cylinders. Liquid gasoline 
from the gas tank is introduced into the venturies 46 through a liquid 
fuel line 52 that is connected through valve 51 to fuel lines 50. Fuel 
lines 50 lead to gasoline reservoirs 49 and fuel lines 48 leading to each 
of the venturies 46. As air is directed downward from air filter housing 
40 through venturies 46, liquid gasoline is introduced from gasoline fuel 
lines 48 into the venturies and mixed therewith for subsequent combustion 
in the cylinders. Valve 51 is installed between the gaseous fuel lines 52 
and 50 to provide a means for selectively shutting off or opening up the 
flow of liquid gasoline from fuel line 52 into fuel lines 50. 
The gaseous fuel system includes a conventional converter 56 for converting 
liquid fuel such as liquid propane to a gaseous state. It will be 
appreciated that any combustible gaseous fuel such as hydrogen gas, 
methane gas, natural gas, or the like, may be used with the gaseous fuel 
system and gaseous fuel mixer of the present invention. Converter 56 also 
includes a conventional diaphragm means (not shown) for introducing the 
gaseous fuel into a gaseous fuel line 55 at atmospheric pressure. A valve 
54 is positioned between the gaseous fuel lines 55 and 38 to provide means 
for selectively shutting off or opening up the flow of gaseous fuel from 
gaseous fuel line 55 into gaseous fuel line 38. 
With valve 54 in the open position, gaseous fuel is introduced through 
gaseous fuel line 55 into gaseous fuel line 38 and channel members 16 and 
12. As incoming air flows through snorkel 15, it strikes the leading 
surface of second channel member 12 causing the air flow to be diverted 
around the second channel member 12. The air flowing past holes 18 creates 
a partial vacuum in the vicinity of holes 18. This vacuum is enhanced by 
the increased cross-sectional configuration of snorkel 15, which is 
typical of the snorkels found in most vehicles. Since the air flowing 
through snorkel 15 is also near atmospheric pressure, the vacuum imposed 
around holes 18 results in a pressure differential between the gaseous 
fuel within second channel member 12 and the area within snorkel 15 
immediately proximate to holes 18, thus drawing the gaseous fuel from 
second channel member 12 through holes 18 and into snorkel 15 to mix with 
the air flow. 
The air entering air intake conduit 62 (see FIG. 5) through air inlet 64 is 
maintained at atmospheric pressure regardless of the speed of the vehicle 
by positioning air inlet 64 perpendicular to the line of movement of the 
vehicle 60. Thus, the rate of the air flow through air intake conduit 62 
is determined solely by the demand of the engine cylinders. As the engine 
cylinders work harder and require more air, the air flow through snorkel 
15 increases and the vacuum imposed around holes 18 increases 
proportionately, causing the gaseous fuel mixer to release a 
proportionately greater amount of gaseous fuel into the snorkel 15. 
Conversely, when the air demand of the engine is decreased, the vacuum 
imposed around holes 18 and the amount of fuel released into snorkel 15 
decrease in proportion to the decrease in the air flow through snorkel 15. 
Thus, irrespective of the rate of the air flow through snorkel 15, the 
same gaseous fuel/air ratio is achieved by the gaseous fuel mixer. 
Once it enters the snorkel 15, the gaseous fuel mixes with the air to form 
a combustible gaseous fuel/air mixture. To ensure that the optimum ratio 
of gaseous fuel to air is obtained for combustion, the flow of gaseous 
fuel through the gaseous fuel mixer is adjusted by turning handle 32 of 
stopcock 31 as described above. 
The gaseous fuel/air mixture next enters air filter housing 40 where it is 
filtered by air filter 42 before passing into carburetor 44. Air filter 42 
not only filters out foreign particles within the gaseous fuel/air 
mixture, but also mixes the gaseous fuel and air into a nearly perfect 
homogeneous mixture. This is thought to be due, in part, to the extremely 
small openings in air filter 42 through which the gaseous fuel and air 
must pass. By the time the gaseous fuel/air mixture passes through the 
carburetor 44 and into the cylinders of the internal combustion engine, 
the mixture of the gaseous fuel with the air is nearly perfect, with the 
result that all engine cylinders receive substantially the same ratio of 
gaseous fuel to air for subsequent combustion thereof. Thus, stopcock 31 
can be adjusted so that each cylinder ultimately receives the optimum 
gaseous fuel/air mixture for combustion, resulting in exceptional fuel 
efficiency. 
When the vehicle operator desires to operate the vehicle on liquid gasoline 
only, he turns valve 54 to the closed position and turns valve 51 to the 
open position. Conversely, if he wishes to operate the vehicle on gaseous 
fuel alone, he turns valve 51 to the closed position and valve 54 to the 
open position. Similarly, the vehicle can be operated by both fuel systems 
simultaneously, by turning both valves 51 and 54 to the open position. 
Since the gaseous fuel mixture is installed into the air intake system 
before the air filter 42 where there is no congestion of engine parts, 
relatively easy installation of the gaseous fuel mixer can be 
accomplished. Moreover, installation into the air intake system is a quick 
and easy procedure, requiring no significant adaptation or modification of 
existing equipment. The same gaseous fuel mixer can be installed in 
virtually all vehicles. Additionally, no precision machining is needed to 
manufacture the gaseous fuel mixer, since any precise fuel flow rate can 
be achieved by simply adjusting the fuel flow regulator. 
Because the gaseous fuel mixer is relatively small and mounted to the air 
intake system before the air filter 42, the gaseous fuel mixer does not 
disturb the existing air flow to any significant degree and the gaseous 
fuel travels a longer pathway before reaching the pistons and cylinders, 
thus giving the gaseous fuel and air plenty of time to mix homogeneously. 
The gaseous fuel mixing system of the present invention provides for 
exceptionally smooth acceleration of the vehicle. Positioning the gaseous 
fuel mixer before the air filter 42 decreases the influence of the engine 
vacuum on the mixer during engine acceleration due primarily to (1) the 
relatively long pathway from the cylinders to the mixer; (2) the 
substantial air impedance between the cylinders and the mixer; and (3) the 
relatively large cross-sectional area of the air intake system where the 
mixer is positioned. Thus, being negligibly influenced by the engine 
vacuum, the gaseous fuel mixer maintains a constant gaseous fuel/air ratio 
irrespective of the air flow rate through the air intake system, even 
during engine acceleration. 
The following fuel efficiency data was obtained from installation of one 
prototype of the gaseous fuel mixer in a 1980 Honda 1500 DX Civic (4 
cylinders), operating on propane gas: 
______________________________________ 
Idle/Cruise 
Full Throttle 
______________________________________ 
Air/Propane Fuel Ratio 
14.6/1 14.0/1 
Carbon Monoxide Emission 
0.5% 1.60% 
______________________________________ 
Since the gaseous fuel/air ratio remains constant, no gaseous fuel is 
wasted during engine acceleration. Moreover, as the pistons and cylinders 
require more gaseous fuel/air mixture in response to engine acceleration, 
the increased demand is met immediately since there is plenty of gaseous 
fuel already mixed with air waiting to be combusted in the snorkel 15, the 
air filter housing 40, the carburetor 44, and all other locations within 
the engine between the gaseous fuel mixer and the engine cylinders. 
Because the engine can immediately begin to use this nearly perfectly 
mixed gaseous fuel/air reserve to begin acceleration of the engine, the 
gaseous fuel mixer has more than adequate time to replenish the gaseous 
fuel/air supply within the engine system, thus negating the instance of 
wasted fuel normally experienced during the air response delay. Moreover, 
this "reserve" of gaseous fuel/air mixture enables the engine to 
accelerate more quickly and smoothly. 
Additionally, the mixing of the gaseous fuel with the incoming air is not 
affected by a dirty or wet air filter, or any other impedance of the air 
flow through the engine system. This is a consequence of positioning the 
gaseous fuel mixer within the air intake system before the air filter 42. 
If the air flow is impeded by a dirty air filter or other foreign 
substance, the gaseous fuel mixer automatically decreases the amount of 
gaseous fuel released into the air intake system to correspond to the 
decrease in air flow. Thus, even if the vehicle owner is negligent with 
regard to maintenance, the fuel efficiency of the vehicle will not be 
substantially affected. 
Somewhat surprisingly, impedance of the air flow between the air filter 42 
and the cylinders actually enhances the efficiency of the gaseous fuel 
mixer during engine acceleration. Impedance of the air flow between the 
air filter 42 and cylinders tends to reduce the effect of the engine 
vacuum imposed on the mixer during engine acceleration, thus making 
acceleration a smoother transition. The air filter 42 is especially a 
significant factor in retarding the increased air flow through the engine 
system caused by the engine vacuum during acceleration. Thus, positioning 
the gaseous fuel mixer before the air filter 42 helps to ensure that a 
constant gaseous fuel/air mixture is maintained. 
Another preferred embodiment of the gaseous fuel mixer is shown in FIG. 6. 
This preferred embodiment is similar to the preferred embodiment of FIG. 
3, except that it has a second channel member 70 with a closed end 71 in 
lieu of a cap. This preferred embodiment of the gaseous fuel mixer is thus 
mounted to snorkel 15 by drilling a single hole in the bottom of the 
snorkel 15. Second channel member 70 is inserted through the hole so as to 
be disposed within snorkel 15 such that holes 18 face the air filter 52. 
The second channel member 70 is then threadingly mounted to first channel 
member 16 and secured to snorkel 15 by a securing nut 72. The preferred 
embodiment of FIG. 6 operates in substantially the same manner as the 
preferred embodiment of FIG. 3, the only important difference between the 
two preferred embodiments being the method of attachment to snorkel 15 and 
the method of closing the upper end of the second channel member. 
Still another preferred embodiment of the gaseous fuel mixer is shown in 
FIGS. 7 and 8. This preferred embodiment includes a single channel member 
80 having a face 81 with a plurality of holes 82 formed therein. This 
preferred embodiment of the gaseous fuel mixer is mounted to the snorkel 
15 by drilling a single hole in the bottom of the snorkel 15, positioning 
channel face 81 within the hole so as to be flush with the bottom surface 
of snorkel 15, and applying a ring of glue or sodder 84 around the channel 
80 to secure channel 80 to the snorkel 15. Gaseous fuel is introduced into 
the channel 80 and flow of the gaseous fuel is regulated by turning 
stopcock handle 32 in a manner similar to that of the embodiment of FIG. 
3. Holes 81 provide gaseous communication between snorkel 15 and channel 
80 so that air flowing through snorkel 15 will impose a vacuum around 
holes 82 and draw the gaseous fuel through channel 80, out holes 82 and 
into the snorkel 15 to be mixed with the air therein. 
The invention may be embodied in other specific forms without departing 
from its spirit or essential characteristics. The described embodiments 
are to be considered in all respects only as illustrative and not 
restrictive. The scope of the invention is, therefore, indicated by the 
appended claims rather than by the foregoing description. All changes 
which come within the meaning and range of equivalency of the claims are 
to be embraced within their scope.