Fuel vaporizer for internal combustion engine

The fuel vaporizer of the present invention is provided for the purpose of improving the efficiency and decreasing the pollution of internal combustion engines, more particularly those used in automobiles and employing gasoline as a fuel. The fuel vaporizer includes a housing forming three separate chambers. A coiled tube extends within the central chamber and its inlet end portion extends through the first chamber and is connected to the outlet of the gasoline pump. The outlet of the coil communicates with the third chamber, which in turn is connected by a tubing to the carburator of the engine. The central chamber is connected in series with the engine cooling circuit by means of two end tubes extending through the first and last chamber, respectively, and opening within said central chamber. Air is bled from the air intake of the carburator; is passed through the first chamber; and is circulated back to the intake manifold downstream of the carburator. The first and last chambers are filled with granular material and the two end tubes are provided with heat-exchanger plates. The bled air is heated in the first chamber. The gasoline is progressively heated and vaporized to a dry vapor while flowing through the coil and through the heated granulated material in the last chamber before it is fed to the carburator.

The present invention relates to a fuel vaporizer for internal combustion 
engines. 
BACKGROUND OF THE INVENTION 
Various attempts have been made to pre-heat the gasoline in an internal 
combustion engine prior to feeding the same to the carburator, in order to 
improve mixture of the gasoline with the air and prevent the introduction 
of droplets of gasoline within the engine, which results in poor 
combustion and high pollution. 
In known gasoline pre-heaters, there is often production of vapor locks 
because of localized overheating of the gasoline in the fuel line. This 
blocks the free flow of gasoline to the carburator, with consequent 
stoppage of the engine. To avoid vapor lock, the gasoline is not heated as 
high as it should be, with the result that gasoline droplets still find 
their way into the intake manifold. In some other known gasoline 
pre-heating systems, the amount of pre-heated gasoline held in the system 
is quite large, and this is a cause of possible explosion. 
OBJECT OF THE INVENTION 
It is the object of the present invention to provide a gasoline pre-heating 
system for internal combustion engines, which obviates the above-noted 
disadvantages and which is characterized by the fact that the gasoline, or 
other liquid fuel, is boiled and vaporized into a gas before it is fed to 
the engine carburator. 
Still another object of the invention is to provide a gasoline vaporizer 
system in which there is efficient exchange between the fuel and the 
heating medium, and in which a minimum amount of fuel is heated and 
vaporized before its admission to the carburator, whereby the device is 
safe in its use. 
Another object of the present invention is to provide means for injecting 
hot air directly into the intake manifold along with the engine fumes in 
order to furnish combustion air for these fumes, while not cooling the 
fuel and air mixture supplied to the engine. 
Another object of the present invention is to provide a system of the 
character described, which can be installed in association with existing 
carburators without modifying the latter, except requiring adjustment of 
the carburator needle valves to obtain a leaner mixture. 
SUMMARY OF THE INVENTION 
The fuel vaporizer device of the invention comprises first and second 
separate chambers, means for circulating fuel through the first chamber 
and for delivering it to the second chamber, means for progressively 
heating the fuel in the two chamber and thus vaporize the fuel, so that 
the fuel in the second chamber will be a vapor state. Granular material 
filling the second chamber is heated and is in intimate heat-exchange 
relation with the fuel to thereby complete conversion of the fuel to the 
gas state. The gaseous fuel is delivered from the second chamber to the 
carburator. There are means for bleeding a portion of the air entering the 
carburator air intake and for delivering it to the intake manifold of the 
engine downstream from the carburator. This bled air is preferably heated 
in a third chamber of the device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The vaporizing device V comprises a cylindrical housing 1 completely 
jacketed by an external heat-insulating layer 2 and forming three separate 
chambers disposed in end-to-end relationship, namely: a first chamber 3, a 
central main chamber 4 and a third chamber 5, chambers 3 and 4 being at 
the inlet and outlet end, respectively, of the housing. 
The three chambers are separated from one another by fixed partitions 6 and 
7. A coil 8 is located within the central chamber 4, has a cylindrical 
shape and is spaced inwardly from the housing 1 and from partitions 6, 7. 
The tube spirals of coil 8 are contiguous. The coil 8 has a straight inlet 
portion 9, which extends through partition 6, through the first chamber 3 
and through the end wall 10 of the housing and is adapted for connection 
with a flexible tubing 11, fitted with the conventional check valve, as 
shown, and connected to the outlet of the fuel pump (not shown) of the 
internal combustion engine A. The outlet end portion 9' of the coil 8 is 
welded, or otherwise secured, in a liquid-proof manner around a hole in 
the partition 7, so that the outlet of the coil is in direct communication 
with the third chamber 5. This outlet is covered by a filter screen 12, as 
clearly shown in FIG. 3. The bottom of the third chamber 5 is in 
communication with a gasoline outlet nipple 13, which is adapted to be 
connected with the conventional fuel inlet of the conventional carburator 
C of the engine by means of a flexible tubing 14, which is preferably 
heat-insulated. The inlet of nipple 13 is also provided with a screen 
filter 15. The gasoline, or other type of fuel in coil 8, is heated by a 
liquid filling the main central chamber 4, said liquid being derived from 
the cooling liquid circuit of the engine A. More particularly, the hot 
liquid, which is normally water preferably added with an anti-freeze, is 
fed into the main chamber 4 by means of an inlet nipple 16, which is fixed 
to the partition 6 and communicates with the chamber 4 at one end, while 
the other end of the inlet nipple 16 extends outwardly of the housing 1 
and is adapted to be connected to a flexible tubing 17 (see FIG. 1) 
adapted to be connected to the cooling liquid circuit of the engine 8. The 
liquid in chamber 4 leaves this chamber through an outlet nipple 18 
extending centrally through the third chamber 5, outwardly of the housing 
and adapted to be connected by a flexible tubing 19, again adapted to be 
connected to the cooling liquid circuit of the engine. Preferably, the 
tubings 17 and 19 are series-connected in the hot liquid line going to the 
conventional passenger cabin heater of the automobile, so as to obtain 
liquid circulation through the vaporizer unit of the invention. As shown 
in FIG. 2, in order to obtain better heat-exchange relationship between 
the hot liquid in chamber 4 and the gasoline in the coiled tube 8, there 
is provided a spirally-shaped strip 20 located within the coil 8 and 
having flat narrow tabs 21 entering the inlet and outlet nipples 16 and 
18, respectively, so as to hold the strip 20 in correct position. The 
liquid issuing from nipple 16 within the main chamber 4 flows on each side 
of the end tab 21 and then is caused by strip 20 to move in a spiral 
within the chamber 4 so as to extend the time the liquid is in contact 
with coil 8. At least part of the heating liquid tends to flow back along 
the outside of the coil 8 by passing in the space between the endmost 
spiral of coil 8 and the partition 7, as shown by arrow 22 in FIG. 2. 
Thus, the liquid recirculates all along the outside of the coil 8 and 
returns inside the coil at the inlet end of chamber 4, as shown by arrow 
23. The heating liquid finally exits on each side of the end tab 21 of the 
strip 20 through the outlet nipple 18. 
The inlet nipple 16 extends centrally of the first chamber 3 and is fitted 
with surrounding metal discs 24. Similarly, the outlet nipple 18 extends 
centrally through the third chamber 5 and is also fitted with circular 
discs 24. Both chambers 3 and 5 are filled with a granular material 25, 
such as charcoal, and preferably activated charcoal. The granular material 
25 is in physical contact with the discs 24 and with the nipples 16 and 
18, respectively, so that the granular material will be heated by the 
heating liquid going through the nipples 16 and 18. The chambers 3 and 5 
are filled with the granular material 25 through couplings 26 and 27. Once 
the chambers are full, coupling 27 for the third chamber 5 is either 
plugged completely or provided with a manometer 28 to indicate the fuel 
pressure within the chamber 5. Normally, this manometer is not used and 
the coupling 27 is simply plugged. Coupling 26 is connected by a flexible 
tubing 29 (see FIG. 1), to an elbow 30 secured to, and in communication 
with, the interior of the central part of the conventional air filter 
casing 31 for the carburator C of the engine A, said casing 31 normally 
holding an annular air filter disposed in the radially outward portion of 
said casing. This casing is fitted with the normal air intake conduit 32 
for admitting air on the outside of the air filter within the casing 31. 
Therefore, elbow 30 is in communication with the portion of the casing on 
the downstream side of the air filter close to the normal bolt 33 fixed to 
the carburator air inlet and serving to fix the air filter casing 31 
positioned on top of the carburator by means of the usual nut 34. The air 
intake conduit 32 is also normally fitted with a conventional 
thermostatically-operated damper assembly 35 which, depending on outside 
weather, either admits air from the inlet at the outer end of conduit 32, 
or air through a side air intake 36, which is closer to the top of the 
engine and, therefore, admits warmer air. Thus, the temperature of the air 
entering the carburator can normally be controlled within a certain range. 
The first chamber 3 is provided at its bottom with an air outlet elbow 37 
having a filter screen 38 at its inlet end. This elbow 37 is connected by 
flexible tubing 39 (see FIG. 1) to a T connection 40, which is in turn 
series-connected in the conventional line 41 which connects the usual PCV 
valve 42 on top of the engine A with the downstream end of the carburator, 
that is for direct connection into the intake manifold D of the engine, as 
shown at 43. Therefore, the oil fumes originating in the engine are mixed 
with hot air and then fed directly into the intake manifold. Vaporizer 
device V has a bracket 44 for fixing device V in a suitable position close 
to engine A. 
When the engine is running, there is a greater vacuum at the downstream end 
of the carburator C at the level of the intake manifold D, than in the air 
intake for the carburator, that is at the central part of casing 31. 
Therefore, filtered air will be bled from the air intake of the carburator 
through tubing 29, first chamber 3 and tubing 39 directly into the intake 
manifold downstream of the carburator. This bled air is heated when 
passing through first chamber 3, because it is in intimate heat-exchange 
relationship with the granular material filling this chamber and in turn 
heated by the inlet nipple 16 and the discs 24. The granular material 25 
in the first chamber 3 also heats up the fuel, or gasoline, circulating 
through inlet section 9. Thus, the fuel is progressively heated in the 
first chamber without direct contact with the heating liquid in main 
chamber 4. When the liquid flows through the coil 8, it is then further 
progressively heated first to a boiling temperature and then vaporized, so 
that fuel in vapor phase enters the third chamber 5. In this third 
chamber, there might still be droplets of liquid fuel admixed with the 
gaseous fuel. Both come in intimate contact with the granular material 25 
filling this chamber. This granular material is heated by heat-exchange 
relationship with the discs 24 and the outlet nipple 18, and any remaining 
fuel droplets are completely vaporized, whereby completely gaseous fuel 
issues from the third chamber to be admitted to the carburator. 
This carburator is conventional and it has been found that it need not be 
modified and the gaseous vapor would then enter directly into the bowl 
provided with the usual float valve. However, the needle valves 
controlling fuel admission into the venturi of the carburator have to be 
regulated by means of the usual adjusting screws, not shown, so as to form 
a leaner mixture than otherwise necessary when using cold liquid fuel. The 
pressure existing within the third chamber would normally be approximately 
the pressure delivered by the fuel pump. 
Because fuel is mixed with the air in the carburator while in completely 
gaseous state, it will be appreciated that no liquid droplets are present 
which would cause poor combustion. Much greater fuel efficiency is 
obtained and, consequently also, less pollution. 
The pre-heated air circuit described, including the first chamber 3, forms 
a safety system because any sudden back flow of vaporized fuel through the 
air intake of the carburator will be immediately sucked by the 
air-bleeding path back into the intake manifold of the engine. Also, 
because the bled air is injected along with the engine oil fumes and in 
hot condition, it will provide for better combustion of these fumes. 
As granulated material filling the two end chambers, it is preferred to use 
activated charcoal, since the latter has good filtering action for both 
the air and the gaseous fuel, and since it has an absorbent capacity to 
absorb moisture in the air circulating through the first chamber and in 
the gaseous fuel in the third chamber. But the main purpose of the 
granular material is to act as good heat-exchanging surfaces with the air 
and fuel, respectively, and to effectively decrease to a minimum the 
volume of gaseous in chamber 5. 
The spirally-wound strip 20 located within the main chamber 4, is 
preferably coated with a heat-reflecting surface, such as chromium, which 
has been found to reflect the heat within heating liquid directly onto the 
coil 8, thereby resulting in a still better heat-exchange relationship 
with the gasoline flowing through the coil 8. 
With all these arrangements, it is therefore possible to make the vaporizer 
device in a relatively small size for ease of installation of the device 
within the engine compartment. Yet the unit effectively completely 
vaporizes the fuel circulating therethrough and eliminates any remaining 
liquid droplets in the fuel. 
The above-described vaporizer unit has been tested by having been installed 
on a passenger car, namely: a Pacer model manufactured by American Motors 
Corporation. Tests have been carried out for 10,000 miles, both in city 
and countryside driving and has averaged 45 miles per Imperial gallon, the 
car being rated to normally give a mileage of 17 to 19 miles per Imperial 
gallon. 
The vaporizer device of the present invention is designed to heat the 
gasoline up to a temperature of about 250.degree. F. The heated gasoline 
is maintained at a pressure above normal atmospheric pressure as produced 
by the gasoline pump of the engine. This temperature of 250.degree. F. is 
much above the normal boiling temperature of about 100.degree. F. at 
normal atmospheric pressure for gasoline and, therefore, all of the 
gasoline is fed in gaseous state to the carburator.