Carbon-filled fuel vapor filter system

A carbon-filled fuel vapor filter system, including a polymer housing, the polymer housing including a hose inlet, a hose outlet, and a formed block of carbon pellets or granules with a polymer binding between the carbon pellets or granules contained within the fuel filter housing.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to a fuel vapor filter, and more 
particularly, pertains to a carbon-filled fuel vapor filter canister. 
2. Description of the Prior Art 
Gasoline Emission Control--A principal application of activated carbon is 
in the capture of gasoline vapors that escape from vents in automotive 
fuel systems. Under EPA regulations, all U.S. motor vehicles produced 
since the early 1970s have been equipped with evaporative emission control 
systems. Most other auto producing countries now have similar controls. 
Fuel vapors vented when the fuel tank or carburetor is heated are captured 
in a canister containing 0.5 to 2 L of activated carbon. Regeneration of 
the carbon is then accomplished by using intake manifold vacuum to draw 
air through the canister. The air carries desorbed vapor into the engine 
where it is burned during normal operation. Activated carbon systems have 
also been proposed for capturing vapors emitted during vehicle refueling. 
Activated carbon is used at many gasoline terminals to capture vapor 
displaced when tank trucks are filled, after the car has been turned off 
after having run, sitting in hot weather, and at the gas station. 
Typically, the adsorption vessels contain around 15 m.sup.3 of activated 
carbon and are regenerated by application of a vacuum. The vapor that is 
pumped off is recovered in an absorber by contact with liquid gasoline. 
Similar equipment is used in the transfer of fuel from barges. The type of 
carbon pore structure required for these applications is substantially 
different from that used in solvent recovery. Because the regeneration 
conditions are very mild, only the weaker adsorption forces can be 
overcome, and therefore, the most effective pores are in the mesopore size 
range. A large adsorption capacity in these pores is possible because 
vapor concentrations are high, typically 10-60%. 
Prior art fuel vapor filters have included loose carbon granules in a 
housing. The cost to manufacture these types of fuel vapor filters as 
either original equipment, or after-market equipment is expensive. 
Further, the granules can sink and settle, and loose their efficiency over 
time. Furthermore, prior art fuel vapor filters have numerous parts which 
require manufacture and later assembly. 
FIG. 1 illustrates a representative prior art fuel vapor filter with many 
parts, all of which are eliminated by the present invention. 
The process used to manufacture these canisters is expensive and dirty. 
Most importantly the current technology for current loose carbon granule 
type canisters requires many parts. These parts are eliminated with the 
herein described invented carbon block technology. In addition, due to 
settling problems of granular carbon fuel vapor filters in the prior art, 
the canisters are not filled to capacity. 
Prior art canister filters that use loose granules can be converted to 
block technology and will hold more carbon, thus increasing performance 
capacity. Many parts that are in the prior art loose type canisters will 
be eliminated. These include bottom retainer screen and foam pad, pressure 
retaining strip and lock nut and foam pad and filter paper. Channelling in 
the present invention is eliminated by using a block of bonded carbon 
pellets for the present invention. As air will take the course of least 
resistance a passageway could eventually develop, whereby the air will be 
taking a path not coming into contact with any carbon, which will then 
render the prior art canister virtually useless. 
The present invention provides a fuel vapor filter which includes carbon 
pellets bound together with a polymer to prevent settling or compacting, 
and also addresses the shortcomings of the prior art devices by 
eliminating prior art parts, and eliminating channeling and also providing 
a cleaner manufacturing process. 
SUMMARY OF THE INVENTION 
The general purpose of the present invention is a fuel vapor filter with 
carbon pellets, bound with a polymer internally aligned in the fuel vapor 
filter housing. The carbon granules trap and hold these vapors until a 
reverse vacuum is placed on the canister. The vapors are then directed to 
the carburetor where they are burned. The auto makers are looking for ways 
to increase the capacity of these canisters while not having to increase 
the canister size. They are also looking for a better way to reduce costs 
and have the vapor filter manufactured with a cleaner process, as filling 
these canisters with carbon granules is a very dusty and/or dirty process. 
According to one embodiment of the present invention, there is provided a 
fuel vapor filter with a polymer housing, an inlet hose, an outlet hose, 
and carbon pellets bound together with a polymer in the form of a carbon 
block within the polymer canister housing of the fuel vapor filter. 
One significant aspect and feature of the present invention is a fuel vapor 
filter with at least one internally formed carbon block element. 
Another significant aspect and feature of the present invention is a 
cleaner manufacturing process. 
A further significant aspect and feature of the present invention is that 
more carbon is actually used in the canister as compared to granules of 
carbon which ultimately sink and compact in the canister. Different sized 
granules or pellets can be used, as well as different sizes of filter 
housings. 
Yet another significant aspect and feature of the present invention is that 
costly extra filter parts are eliminated. 
Still another significant aspect and feature of the present invention is 
that performance and efficiency are greatly improved. 
Yet a further significant aspect and feature of the present invention is 
the elimination of channeling through the center or sides of a carbon 
granule filled interior. 
Still a further significant aspect and feature of the present invention is 
the incorporation of side flow directional flutes in the canister side 
walls to prevent air travel between the side of a carbon pellet block and 
the side wall of a canister. 
Having thus described the embodiments of the present invention, the 
principal object hereof is to provide a fuel vapor filter with an internal 
carbon block.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 2 illustrates an exploded view of the fuel vapor filter 10, including 
a high temperature polymer housing canister 12, a planar housing top 14 
for sealing of the upper portion of the housing canister 12 and a mass of 
carbon pellets 16 which are bound together by a polymer which fills the 
interior of the housing canister 12. The housing canister 12 includes a 
rectangular shaped base 18, cylindrical inlet connection port 20, a 
cylindrical outlet connection port 22, sides 24, 26, 28 and 30 extending 
vertically from the base 18, and a semicircular shaped compartment 31 
located at the top of side 26. A holed bracket 32 is located at the lower 
portion of side 24 and a notched bracket 34 is located at the upper 
portion of side 24, each member of which is used to secure the fuel vapor 
filter to an appropriate mounting surface. A lip 36, having a sealing 
surface 38, aligns at about the top edges of sides 24-30 and the 
compartment 31. 
The planar housing top 14 includes a protrusion 40 on its upper surface to 
insure proper right side up alignment with the lip 36 and the sealing 
surface 38. A plurality of protrusions 42a-42d extend from the bottom 
surface of the planar housing top 14 to aid in alignment of the housing 
top 14 about a vertical rod 44 of FIG. 2. 
FIG. 3 illustrates a top view of the housing canister 12 and the planar 
housing 14 where all numerals correspond to those elements previously 
described. The housing canister 12 includes a panel member 46 extending 
upwardly from the base 18 between the sides 24 and 28 to a distance of 
approximately 3/4 the height of the housing canister 12 for purposes of 
illustration and shall not be construed as limiting to the scope of the 
present invention. This panel 46 divides the interior of the housing 
canister 12 into opposing chambers 48 and 50 formed by the base 18, sides 
24-30 and the common divider wall 46 separating the chambers 48 and 50. 
Chamber 48 is an inlet chamber and chamber 50 is an outlet chamber. Fuel 
vapors travel through the block of carbon pellets 16 located in the inlet 
chamber 48, over the space above the panel 46, separating the inlet and 
outlet chambers 48 and 50, and through the outlet chamber 50. 
FIG. 4 illustrates a cross-sectional view of the fuel vapor filter 10 where 
all numerals correspond to those elements previously described. A 
plurality of inwardly extending members, such as flutes 52a-52n align 
about the interior of the walls 26, 28, 30 and 24 which prevent vapors 
from flowing along the sides of the blocks of carbon pellets 16. The 
members can be either horizontal or at an angle, but not vertical. The 
flutes also provide additional strength to the filter housing. The grooves 
52a-52n also aid in securement of the blocks of carbon pellets 16 within 
the interior of the chambers to minimize movement and chafing of the block 
of carbon pellets 16 with respect to the sides of the housing canister 12. 
Flow of gas vapors flows through the inlet connection port 20, through the 
carbon-granule filled chamber 48, over the top of the panel 46, through 
the carbon-filled chamber 50 and finally through the outlet connection 
port 22. Gas vapors are absorbed by the blocked carbon pellets 16. Chamber 
31 also includes a panel member 54 extending across the mouth of the 
chamber 31, and includes a passageway 56 between the chamber 50 and the 
chamber 31 for the flow and passage of gas vapors. The side inwardly 
angularly extending members help retain the molded and bonded carbon 
pellet block in position, and also prevent vapors from traveling up along 
the inner sides of the canister. The inner members can extend slightly 
into the carbon block. 
MODE OF OPERATION 
The carbon block can either be formed preferably in the polymer housing of 
the fuel vapor filter internally, or formed and dropped in place during 
assembly. If a drop-in block is utilized, an outer skin on the drop-in 
block may be required. The teachings of the present invention apply to any 
make or model of fuel vapor canister, and is not limited to the fuel vapor 
canister structure in the drawing. 
The carbon block is a mixture of carbon pellets, such as those available 
from Westvaco and a polymer for binding the carbon pellets together, such 
as Microthene in a 4-8% range. The carbon pellets or granules can be 2 mm 
or 10.times.25 to 20.times.100 as an example. In one mode of manufacturing 
the fuel vapor filter, the mixture of carbon pellets and polymer, such as 
a powdered polymer, can be filled into a high-temperature polymer housing 
canister and placed under pressure when the housing is in a metal fixture. 
The mixture is then heated at an elevated temperature, such as in a range 
of 250.degree.-500.degree. Fahrenheit, and by way of example 350.degree. 
Fahrenheit in a downward applied pressure in a range of 100-200 PSI for a 
predetermined time period, and such as in a range of 1-25 minutes. This 
mixture provides for the bonding of the granules to each other, while 
still permitting passage of air flow and vapor flow. The melt index is a 
function of the polymer binder, the temperature, the pressure and time. 
Every contour is then filled with carbon in a tight fit on the canister. 
The high temperature polymer shell can be placed into a metal fixture, and 
the carbon-polymer mixture can be cooked under pressure. 
In operation, the optional side grooves prevent the vapors and air from 
traveling up between the sides of the canister and the carbon block, and 
also provide for the securing and holding of the carbon block within the 
housing canister. The carbon block can also have an optional non-permeable 
outer skin, such as a polymer skin. 
Specifically, there are two and soon to be three purposes for these 
canisters placed on the vehicle that use gasoline, not diesel fuel. 
Environmental regulations require that the auto makers not allow fumes to 
escape the gas tank and be emitted into the atmosphere. This happens under 
the following circumstances. First, when one's vehicle is outside in the 
heat, the gasoline will vaporize. When this happens it goes from the gas 
tank via a hose to the fuel vapor canister. Secondly, after one has been 
driving the vehicle, the heat from the car after one turns the car off 
will also cause the gasoline to vaporize, as well as vapors generated from 
the outside ambient air. Again, these vapors are directed to the carbon 
canister. When the engine is started, a vacuum is placed on the canister 
which pulls the trapped vapors out of the carbon block and into the engine 
where the vapors are burned. Thirdly, and possibly soon to be mandatory, 
when one fills up the vehicle with gas, the vapors will again have to 
travel into one of these canisters by regulatory law. 
Appendix 1 illustrates the effectiveness of the present invention. 
##SPC1## 
Various modifications can be made to the present invention without 
departing from the apparent scope hereof. The teachings of the present 
invention apply to all sizes and shapes of fuel vapor filters.