WO2012078660A1

WO2012078660A1 - Systems and methods for improving fuel efficiency

Info

Publication number: WO2012078660A1
Application number: PCT/US2011/063576
Authority: WO
Inventors: Edward Richard Eramian
Original assignee: Greene Environmental Corporation
Priority date: 2010-12-06
Filing date: 2011-12-06
Publication date: 2012-06-14
Also published as: AU2011338541A1; MX2013006328A; EP2649284A4; US20120144800A1; CN103429866B; CA2820029A1; CN103429866A; EP2649284A1; BR112013013954A2

Abstract

Devices and methods for improving fuel efficiency are disclosed herein. According to aspects illustrated herein, there is provided a device for improving fuel efficiency of a combustion engine. The device may include a housing for attachment to an exhaust pipe of a combustion engine and having a pathway extending therethrough. The device may further include a wound body disposed at a distal portion of the housing and designed to permit fluid from the exhaust pipe flowing along the housing to flow through the wound body. In addition, the device may include a barrier positioned within the pathway downstream from the wound body so as to generate a sufficient back pressure along the exhaust pipe to enhance piston stroke efficiency in the combustion system, resulting in an increase in fuel efficiency of the combustion engine.

Description

SYSTEMS AND METHODS FOR IMPROVING FUEL EFFICIENCY

RELATED APPLICATIONS

[001] The present application claims priority to and the benefit of U.S. Provisional Application No. 61/420,071 filed December 6, 2010, which is incorporated herein by reference in its entirety for the teachings therein.

FffiLD

[002] This invention relates to systems and methods for improving fuel efficiency in a combustion engine.

BACKGROUND

[003] Automobile engines convert fuel into energy using an internal combustion engine powered by gasoline, propane, or diesel fuel. Over the years, the carbon-dioxide from combustion engines has led to the global warming and poor air quality. Moreover, oil has been steadily increasing in price due to the dwindling worldwide supply. Because of the sheer number of combustion engines in use today, even a small improvement in fuel efficiency would provide a significant environmental and financial benefits.

SUMMARY OF THE INVENTION

[004] Devices and methods for improving fuel efficiency are disclosed herein. According to aspects illustrated herein, there is provided a device for improving fuel efficiency of a combustion engine. The device may include a housing for attachment to an exhaust pipe of a combustion engine and having a pathway extending therethrough. The device may further include a wound body disposed at a distal portion of the housing and designed to permit fluid from the exhaust pipe flowing along the housing to flow through the wound body. In addition, the device may include a barrier positioned within the pathway downstream from the wound body so as to generate a sufficient back pressure along the exhaust pipe to enhance piston stroke efficiency in the combustion system, resulting in an increase in fuel efficiency of the combustion engine. [005] In other aspects, there is provided a method for improving fuel efficiency of a combustion engine. The method includes a step of directing a flow of exhaust gases from an exhaust pipe of a combustion system along a flowpath Next, a barrier may be disposed in the flowpath of the exhaust gases and a sufficient back pressure may be allowed to be generated back along the flowpath and exhaust pipe to enhance piston stroke efficiency in the combustion system, resulting in an increase in fuel efficiency of the combustion engine.

BRIEF DESCRIPTION OF DRAWINGS

[006] The presently disclosed embodiments will be further explained with reference to the attached drawings, wherein like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the presently disclosed embodiments.

[007] FIG. l a- l b illustrate embodiments of a device for improving fuel consumption of the present disclosure.

[008] FIGS. 2a-2b illustrates an embodiment of a wound body of a device for improving fuel consumption of the present disclosure in operation.

[009] FIGS 3-4 illustrate the effect of including a barrier in a device for improving fuel consumption of the present disclosure on the flow of fluid out of the device.

[0010] FIG.' 5 illustrates an embodiment of a device for improving fuel consumption of the present disclosure.

[0011] While the above-identified drawings set forth presently disclosed embodiments, other embodiments are also contemplated, as noted in the discussion. This disclosure presents illustrative embodiments by way of representation and not limitation. Numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of the presently disclosed embodiments.

DESCRIPTION OF SPECIFIC EMBODIMENTS [0012] According to aspects illustrated herein, there is provided a device to be affixed to an exhaust outlet of a combustion engine in order to improve fuel efficiency of the combustion engine. The device may be connected to an exhaust outlet of a combustion engine to, among other things, aid in generating and maintaining a back-pressure in the exhaust system sufficient to enhance the operational efficiency of the combustion engine and to improve its fuel efficiency.

[0013] Referring to Figs, l a- l b, a device 100 of the present invention includes, in one embodiment, a housing 102 having a pathway 1 04 extending therethrough. The housing 102, as illustrated, may be configured to attach to an exhaust outlet 1 16. To that end, the housing 102 may be of any shape or dimension so long as it can be attached to the exhaust outlet 1 1 6. In an embodiment, as illustrated in Fig. l a, the cross-section of the housing 102 may approximate the cross-section of the exhaust outlet 1 16 to which the housing 102 is attached, so that the housing 102 may form a snug fit with the exhaust outlet 1 16. To the extent necessary, an adapter (not shown) may be provided to facilitate the attachment of the housing 102 to the exhaust outlet 1 1 6. The housing 102, in an embodiment, may be made from any material capable of withstanding the heat and pressure generated from the exhaust outlet 1 16, including, but not limited to, alum inum, steel, stainless steel, aluminized steel pr a combination thereof.

[0014] In reference to Fig. l b, in an embodiment, a perforated screen 1 24 may be positioned at a distal end 120 of the housing 102. The perforated screen 124 may be metallic such as, for example, a punched metal web or a wire mesh. Alternatively, the perforated screen 124 may be constructed by perforating the material used to construct the housing. Of course any material can be used so long as the screen 124 can withstand the temperature and pressure generated by the exhaust fluid 1 1 0.

[0015] The device 100 also includes a wound body 1 06 disposed at a distal portion 108 of the housing 102 and designed to permit exhaust fluid 1 10 from the exhaust outlet 1 16 of a combustion engine (not shown) and along the pathway 104 to flow through wound body 106. In an embodiment, the wound body 106 may be complimentary disposed in the distal portion 108 of the housing 102. The term "complimentary "disposed" refers to the placement of the wound body 106 having substantially the same cross-section as the cross-section of the housing 102. In an embodiment, the wound body 106 may be provided with an outer cross-sectional perimeter that may be at least 70 %, at least 80%, at least 90% or at least 95% of the inner cross-sectional perimeter of the housing 102. In an embodiment, a wound body may be dimensioned so as to fill at least 70 %, at least 80%, at least 90% or at least 95% of the pathway 104 through the housing 102. By way of a non-limiting example, both the housing 102 and the wound body 106 may be cyl indrical, i.e. both have a circular cross- section, and the outer circumference of the wound body 106 may be at least 70 %, at least 80%, at least 90% or at least 95% of the inner circumference of the housing 102, that is, the outer diameter of wound body 106 is at least 70 %, at least 80%, at least 90% or at least 95% of the inner diameter of the housing 102.

, [0016] In an embodiment, the wound body 106 may include a series of overlapping layers 201 - 205, as shown in Figs. 2a-2b, formed by winding one or more materials around a central axis. Although the wound body 106 as shown in Figs. 2a-2b includes five layers 201 -205, it should be understood that the number of layers may be more than five or fewer than five as desired. The wound body 106, in one embodiment, may be provided with spacing between the layers 201 -205 to permit fluid to flow therethrough. To the extend desired, the spacing between the layers 201 -205 may be varied to control the volume and rate of flow through the wound body 106.

[0017] In one embodiment, the wound body 106 may be made of one or more metals or of any other materials capable of withstanding the heat and pressure generated from the exhaust fluid I 1 0 from the exhaust outlet 1 16. In an embodiment, a wound body 106 may be constructed by winding two metal fabrics around a central point. For example, a wired mesh or a similar material may be disposed between the layers 201 -205 formed from metal fabric. The presence of the wired mesh may help ensure that there is sufficient spacing between the layers 201 -205 of the wound body 1 06 to permit exhaust fluid to flow through the wound body 106 and out of the housing 102. If desired, the speed and volume of flow through the wound body may be regulated by varying the spacing between the layers 201 -205, the materials forming the wound body 1 06, coating of the layers 201 -205, or combinations thereof. Being formed by winding one or more materials around a central axis, the wound body 106 may be permitted to move from a first position, in which centrally-located layers 201 -204 are flush with the height of an outer loop 205 as shown in Fig. 2a, to a second position, in which the layers 201 -205 are staggered axial ly relative to one another to give the wound body 106 a - substantially conical shape as shown in Fig. 2b. [0018] As will be described in more detail below, in operation, a combustion engine emits fluid in waves, resulting in periods of high pressure and low pressure. As the pressure and volume of the exhaust fluid can vary due to the cycle of the combustion engine, the layers 20 1 -205 of the wound body 106 may move relative to one another thereby varying the spacing between the layers 201 -205 for the exhaust fluid to flow through the wound body 1 06 and out of the housing 102. In reference to Fig. 2a, during the periods of high pressure, the wound body 1 06 may be in the first position, that is, the centrally-located layers 201 -204 are flush with the height of the outer loop 205. During periods of lower pressure, however, the forces on the wound body may cause the wound body 106 to unwind radially, thus increasing the outer diameter of the wound body 1 06 sl ightly, as well as spacing between the layers 201 -205. In reference to Fig. 2b, during the periods of low pressure, the layers of the wound body 106 may move from the first position to the second position, that is, the layers 201 - 205 move axially relative to each other away from the distal tip 120 of the housing 102 to give the wound body 106 a substantially conical shape, and decrease the spacing between the layers 201 -205.

[0019] In an embodiment, it may be desirable to minimize movement of the wound body 1 06 within the housing 102. To that end, in an embodiment, the housing 1 02 may be provided with a distal portion 108 that may be measurably wider than the rest of the housing 102 so that there is a slight constriction at a juncture between the distal portion 108 and the remainder of the housing 102. The wound body 106, in such an embodiment may be provided with a profile slightly wider than the profile of the rest of the housing 102, but slightly narrower than the profile of the distal portion 108 of the housing 102. In such embodiments, the wound body 106 may sti ll move from the first position into the second position, with the centrally-located layers 201 -204 extending away from the distal tip 120 of the housing 102 toward a middle portion 122 of the housing 102, while the wound body 106 remains within the distal portion 108 of the housing 1 02. It will of course be understood that other means for achieving the above-specified goal may be used.

[0020] In general, Fig. 3 illustrates an embodiment of the device 100 of the present disclosure in which a wound body 302 includes a substantially open passage 304 extending through the center of the wound body 302. Because the exhaust fluid 306 can flow through the passage 304 substantially uninterrupted, the flow rate of the exhaust fluid 306 through the passage 304 may be higher than the flow rate of the exhaust fluid 306 through the remainder of the wound body. As a result, fluid 308 flowing out of a housing 3 10 may be substantially non-uniform in manner. Fluid flowing out of the housing 310 in a substantially non-uniform manner can effect the operational efficiency and fuel efficiency of the combustion engine because in such system a p e-determined back-pressure needed to enhance the operational efficiency of the combustion engine and to improve its fuel efficiency may not be generated or maintained.

[0021] Accordingly, the device 100 may further include a barrier 1 1 2 positioned within the pathway 104 downstream from the wound body 106 to impart a substantially plug, i.e. uniform, flow to the fluid flowing out of the housing 102. The barrier 1 12 may function to control and balance the volume of fluid flowing out of the housing 102 and to generate and maintain a pre-determined backpressure in the exhaust system. The terms "plug flow" and "uni form flow" refer to the type of flow where velocity is constant and the channel length is the same for all streaml ines 400, as shown in Fig. 4. In contrast, the term "non-uniform" refers to the type of flow having streamlines of di fferent velocity and length, such as shown in Fig. 3. The barrier 1 12 may be positioned in such a manner as to impart a substantially plug flow to outlet fluid 1 14 as it exits the housing 1 02. In contrast, as illustrated in Fig. 4, in a device 100 of the present disclosure, when a barrier 1 12 is placed downstream of the wound body 1 06 in alignment with the substantially open passage 126 extending through the wound body 106, fluid 1 14 flowing out of the housing 102 may be substantially uniform in manner. In particular, such placement of the barrier 1 12 may disrupt or interfere with the otherwise uninterrupted flow through the substantially open passage 126 in the wound body 1 06. As a result, the fluid 1 14 may flow out of the housing 102 in a substantially plug manner, i.e. substantially uniform manner. In one embodiment, the barrier 1 1 2 may be placed on the outside of screen 1 24. Alternatively, the barrier 1 12 can be placed on the inside of the screen 1 24 or incorporated as part of screen 124.

[0022] In other embodiments, there may be multiple open passages through which the rate of flow may be higher than through the wound body 106. For example, there may be a space between the outer surface of the wound body 106 and the inner wall of the housing 1 02 due to the difference in size between them, or there may be multiple open passages through the wound body 106. In such embodiments, a single barrier or multiple barriers 1 12 may be used to ensure that the fluid flows out of the housing 102 in a substantially uniform manner. [0023] The barrier 1 12, in an embodiment, may be made from any material capable of withstanding the heat and pressure generated from the exhaust outlet 1 1 6, including, but not limited to, metals, such as, aluminum, steel, stainless steel, aluminized steel, ceramic, or texti le or a combination thereof. In an embodiment, the barrier 1 12 may be made from a solid impermeable material, the barrier may be impermeable in order to block the flow rate through the passage 1 26. In an embodiment, the barrier 1 12 may be made by blocking, or making less permeable, a section or sections of the perforated screen 124 aligned with one or more open passages through which the exhaust fluid 1 10 may by-pass the wound body 106.

[0024] Alternatively, the barrier 1 12 may be permeable. In one embodiment the barrier 1 12 may be from a filter material to filtrate the exhaust fluid in addition to preventing the exhaust fluid from by-passing the wound body 106. The barrier, in an embodiment, may be permeable in order to decrease the flow rate through the passage 1 26 without completely blocking it. To the extent that the flow through the passage 126 can be sufficiently decreased by a permeable barrier 1 12, a substantially uniform flow can be imparted, thereby enhancing the operational efficiency and to improving the fuel efficiency of the combustion engine.

[0025] In an embodiment, the size and the permeability of the barrier 1 12 are selected, so as to ensure that fluid flows out of the housing 102 in a substantial plug manner as well as to ensure that a pre-determined back-pressure is generated and maintained in the exhaust system. As the permeability of the barrier 1 12 increases, the ratio between the area of the barrier 1 1 2 to the area of the perforated screen 124 and between the area of the .barrier to the area of a passage through the wound body 1 06 also increases. That is as the permeability of the barrier 1 1 2 increase, so does the need to increase the size of the barrier 1 12 to balance the flow of fluid out of the housing 102, thereby generating a predetermined back-pressure in the exhaust system sufficient to improve the fuel efficiency of the combustion engine. By way of a non-limiting example, the barrier 1 1 2 is made from a solid material and the area of the barrier 1 12 may be about 22% of the area of the perforated screen 124 and/or about 250% of the passage 304.

[0026] In another aspect, there is provided a method for improving fuel efficiency of a combustion engine. Initially, a housing is affixed to an exhaust outlet of the combustion engine, the filter housing defining a pathway extending therethrough. Next, a wound body is disposed at a distal portion of the housing, in such a manner as to permit fluid within the pathway to flow through the wound body. Thereafter, a barrier can be situated within the pathway downstream from the wound body to impart a substantially plug flow to the fluid exiting the housing.

[0027] The housing 102 may be attached to an exhaust system of a combustion engine, either permanently or removably, in a variety of ways using a variety of attachment devices known in the art. The efficacy of the methods of the present disclosure does not depend on the positioning of the housing 102 inside the exhaust system, and thus the housing 102 may be installed in any part of the exhaust system. In an embodiment, the housing 102 may be removably attached adjacent to the exhaust outlet 1 16.

[0028] In operation, a combustion engine emits gas creating explosions. As shown, for example, in Fig. 1 , the exhaust gas 1 10 leaves the exhaust outlet 1 1 6 and enters a proximal portion 128 of the housing 102, eventually flowing through the wound body 106 and the barrier 1 12 to exit the housing 102 into the atmosphere. The effect produced by each explosion of the fuel in a combustion engine can provoke a high-pressure wave of gases, which flow through the exhaust system and through the housing until being expelled into the atmosphere. Between periods of high pressure, there can be periods of low pressure, which are variable in relation to the rhythm of the explosions. Disposing the wound body 106 in the distal portion 108 of the housing 102 may create a restriction in the flow path of the exhaust gas 1 10, thus transforming variable periods of low pressure into small constant periods. This back-pressure is regulated by the movement of the wound body 106 back and forth between the first position during periods of high pressure to the second position during periods of low pressure. However, this effect may be greatly diminished, if not altogether el iminated, i f the exhaust fluid 1 1 0 is allowed to by-pass the wound body, as described above, and flow out of the housing 1 02 in an nonuniform manner as shown in Fig. 3.

[0029] A barrier 1 12 placed distally of the wound body 106 to control free flow of fluid 1 14 out of the housing 102 may impart a substantially plug flow in the axial direction to fluid 1 14 flowing out of the housing 102, as shown in Fig. 4, thus ensuring that the necessary back-pressure in the exhaust system is maintained. In addition, the barrier I 12, in an embodiment, may help create and maintain a back-pressure in the exhaust system sufficient to improve stroke efficiency of the combustion system pistons, thereby improving the fuel efficiency of the combustion system. As a result, a sufficient back-pressure may be produced in the exhaust system to make the exhaust system more operational ly efficient, thus reducing fuel consumption. In particular, the barrier 1 12 placed distally of the wound body 106 may aid in maintaining a sufficient back pressure in the exhaust system so as to improve efficiency of the stroke cycle of one or more pistons of the exhaust system.

[0030] It may be desirable to maintain a sufficient back pressure in the housing 1 02 as well as in the exhaust system. As described above, the back-pressure inside the housing 102 may be regulated by varying design parameters for the wound body 106 and/br the barrier 1 12. Alternatively or additionally, the perforated screen 124 may be made more or less restrictive as desired. In yet other embodiments, the housing 102 may include a pressure relief valve to relief pressure in the housing 102 as desired. In some instances, the back pressure inside the housing and the exhaust system may become too significant due to the volume and flow rate of the exhaust fluid, thereby comprom ising the fuel efficiency of the combustion engine. The pressure relief valve in the housing 102 may operate to return the back-pressure in the housing to the back-pressure sufficient to optimize the fuel efficiency of the combustion engine.

[0031] In an embodiment, in a device 500 of the present disclosure as shown in Fig. 5, a housing 502 may include a side opening 504 in a side wall 506 in a proximal portion 508 of the housing 502 to permit some of the exhaust fluid 5 10 to exit the housing 502 through this side opening 504. In such embodiments, one or more radial filters 5 12a, 5 12b may be disposed along the walls of the housing to cover the side wall opening. The one or more radial filters 5 1 2a, 5 12b may aid in regulating the backpressure in the exhaust system, either alone or in combination with a wound body 5 14 and a barrier 5 16. In an embodiment, the one or more radial filters 5 12a, 5 12b may also act to reduce emissions of particles from the exhaust to the atmosphere. During periods of high pressure, the one or more radial filters 512a, 512b may expand allowing extra flow of fluid, thereby normalizing back-pressure in the exhaust system. Accordingly, in an embodiment, the one or more radial filters 5 1 2a, 5 1 2b are made of materials with air permeability selected so as to enable the one or more radial fi lters to regulate the back-pressure in the exhaust system. In an embodiment, the one or more filters 5 1 2a, 5 12b may be made from material with air permeability of between about 10 and about 20 feet per minute (cfm), and more preferably between about 12 and about 1 6 as measured according to ASTM D737-96: Standard Test Method for Air Permeability of Textile Fabrics using, by way of a non-limiting example, a Frazier® Differential Pressure Air Permeability Instrument. By way of a non-limiting example, the one or more radial filters may be made from material having air permeability of about 15 cfm.

[0032] In an embodiment, a device 500 of the present disclosure may comprise two radial filters: a first radial filter 5 12a and a second radial filter 5 12b. In an embodiment, the first radial filter 5 12a may be made by wrapping a filter fabric in a metal mesh. Suitable materials for the filter fabric include, but are not limited to, an aramid, a meta-aramid, a polyamide, a polyphenylene sulfide, a p- phenylene- l ,3,4-oxadiazole, polytetraflouroethylene, and basalt. Suitable materials for the metal mesh include, but are not limited to, aluminum, zinc, copper, iron. The first radial filter 5 1 2a may have the same shape as the housing and may extend longitudinally along the walls of the housing for the entire length of the housing. The second radial filter 5 12b may be made from the same or different fabric as the one utilized in the first filter and may have the same or different shape than the shape of the first filter. A portion of the inlet gas may be allowed to by-pass the second radial filter 512b as its sides may not be secured together, a portion of the inlet gas may pass through the walls of the second filter, and finally, a portion of the inlet gas proceed axial ly through the second filter to the wound body. The second radial filter 512b may have any shape, but is preferably formed to ensure uniform distribution of exhaust fluid over the wound body. In an embodiment, the second radial fi lter 512b may be made by forming a filter material into a cone.

[0033] The present disclosure is described in the following Examples, which are set forth to aid in the understanding of the disclosure, and should not be construed to limit in any way the scope of the disclosure as defined in the claims which follow thereafter. The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the present disclosure, and are not intended to limit the scope of what the inventors regard as their invention nor are they intended to represent that the experiments below are all or the only experiments performed. Efforts have been made to ensure accuracy with respect to numbers used (e.g. amounts, temperature, etc.) but some experimental errors and deviations should be accounted for.

[0034] EXAMPLES:

Example 1 : Emissions and Fuel Efficiency [0035] The device of the present disclosure was provided with 1 ) a radial filter with air permeability of 15 cfm was used in place of the regular filter with air permeability of 25 ± 5 cfm; 2) the hole in the filter bobbin was plugged; and 3) a barrier disk was placed downstream from the filter bobbin in alignment with the hole through the filter bobbin. The results of the tests of such device are presented in Table 1 below:

Table 1 : Test Results

[0036] As can be seen from the results, the device having a barrier and or plug resulted in the increase in fuel efficiency over no device and devices having an open hole through the wound body.

Example 2: Emissions

[0037] Three vehicles were tested with and without the devices of the present disclosure according to the European Elementary Urban Cycle and Extra Urban Cycle test protocols. The vehicles were as follows: A01 — Cherry (Tiggo) with 53,607 km; A02— Honda (Fit) with 22,702 km; A03 — Chevrolet (Epica) with 137,235 km. Exhaust emissions of HC, CO and NO_x were collected and analyzed on a grams per kilometer basis for each test phase. The test data is presented

I 1 below:

Table 2: Average tailpipe em issions after a cold start without the device

Table 3: Average tai lpipe emissions after a cold start with the device (B01 ).

[0038] As can be seen from tables 2 and 3, the addition of the device of the present disclosure resulted in the reduced emissions of HC, CO and NO_x. Example 3 : Fuel Economy

[0039] Fuel economy was measured on a l iter per 1 00 ki lometer basis for each test phase. The vehicles were as follows: A0 I — Cherry (Tiggo) with 53,607 km ; A02 - Honda (Fit) with 22,702 km; A03 -- Chevrolet (Epica) with 137,235 km. The test data is presented below:

Table 4: Average fuel consumption without the device

Table 5 : Average fuel consumption with the device [0040] The comparison of the fuel efficiency data from tests without the device (Average 1 ) and the tests with the device (Average 2) is presented in Table 5 below:

\

I Fuel Economy Results I

Vehicle Designation Test Type Average 1 Average 2 Improvement % Improvement

C ery (Tiggo) A01 Urban cycle 12. 16 1 1.26 0.90 7.40%

Chery (Tiggo) AOi Ex-urban Cycle 5.39 4.77 0.62 11.56%

Cher (Tiggo) AOi Integration 7.84 7. 13 0.71 9.05%

Honda (Fit) A02 Urban cycle 8.59 8.77 -0. 18 -2.13%

Honda (Fit) A02 Ex-urban Cycie 4.90 4.63 0.22 4.49%

Honda (Fit) A02 Integration 6.30 6.17 0.13 1.99%

Chevy (Epica) A03 Urban cycle 12.05 11.60 0.45 3.72%

Chevy (Epica) A03 Ex-urban Cycle 5.51 4.96 0.55 9.96%

Chevy (Epica) A03 Integration 7.91 7.40 0.51 6.45%

Table 6: Comparison of fuel consumption

[0041 ] The data in Table 5 shows that the device of the present disclosure improved fuel economy of all three vehicles in a range from 0.3 to 0.7 l iters per ki lometer with an average of 0.5 l iters per kilometer which corresponds to a 7% increase in average fuel economy for the three vehicles tested in this program.

[0042] All patents, patent applications, and publ ished references cited herein are hereby incorporated by reference in their entirety. It wi l l be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or application. Various presently un foreseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those ski l led in the art.

Claims

CLAIMS What we claim is:

1. A device for increasing fuel efficiency comprising: a housing for attachment to an exhaust pipe of a combustion engine and having a pathway extending therethrough; a wound body disposed at a distal portion of the housing and designed to permit fluid from the exhaust pipe flowing along the housing to flow through the wound body; and a barrier positioned within the pathway downstream from the wound body so as to generate a sufficient back pressure along the exhaust pipe to enhance piston stroke efficiency in the combustion system, resulting in an increase in fuel efficiency of the combustion engine.

2. The device of claim 1, wherein the barrier is a perforated screen.

3. The device of claim 1, wherein the wound body has a substantially similar cross-section as the cross-section of the housing.

4. The device of claim 1, wherein the wound body is formed from a plurality of metal fabrics wound together around a central point.

5. The device of claim 1, wherein the wound body includes a series of overlapping layers

wounded around a central axis of the wound body.

6. The device of claim 5, wherein the wound body includes a wired mesh between the

overlapping layer to permit fluid to flow through the wound body.

7. The device of claim 5, wherein the wound body is moveable from a first position where the overlapping layers are flash with one another to restrict flow through the wound body to a second position where the overlapping layers are axially staggered to permit flow through the wound body.

8. The device of claim 1, wherein the housing has a first diameter along a proximal portion of the housing and a second diameter along the distal portion of the housing wherein the second diameter is greater than the first diameter to accommodate the wound body and to restrict the movement of the wound body.

9. The device of claim 1, wherein a perforated screen is positioned distally of the barrier inside the housing.

10. The device of claim 9, wherein as the permeability of the barrier increases, the ratio between the area of the barrier to the area of the perforated screen increases.

11. The device of claim 9, wherein as the permeability of the barrier increases, the ratio between the area of the barrier to the area of a passage of fluid flow increases.

12. The device of claim 1, wherein the housing further includes a relief valve for maintaining a sufficient back pressure along the exhaust pipe to enhance piston stroke efficiency, resulting in an increase in fuel efficiency of the combustion engine.

13. The device of claim 1, wherein the housing includes a side opening in a proximal region of the housing for permitting exhaust gasses to exit the housing radially and one or more radial filters disposed within the housing to cover the side opening.

14. The device of claim 13, wherein the one or more radial filters are selected to cooperate with the barrier to maintain the sufficient back pressure along the exhaust pipe to enhance piston stroke efficiency in the combustion system, resulting in an increase in fuel efficiency of the combustion engine.

15. A method for enhancing fuel efficiency comprising: directing a flow of exhaust gases from an exhaust pipe of a combustion system along a flowpath; disposing a barrier in the flowpath of the exhaust gases; and allowing a sufficient back pressure to be generated back along the flowpath and exhaust pipe to enhance piston stroke efficiency in the combustion system, resulting in an increase in fuel efficiency of the combustion engine.

16. The method of claim 15, wherein, in the step of disposing, a device for increasing fuel

efficiency is attached to the exhaust pipe, the device comprising: a housing for attachment to the exhaust pipe and having a pathway extending therethrough; a wound body disposed at a distal portion of the housing and designed to permit fluid from the exhaust pipe flowing along the housing to flow through the wound body; and the barrier positioned within the pathway downstream from the wound body.

17. The method of claim 16, wherein the wound body is moveable from a first position where the overlapping layers are flash with one another to restrict flow through the wound body to a second position where the overlapping layers are axially staggered to permit flow through the wound body.

18. The method of claim 16, wherein a perforated screen is positioned distally of the barrier inside the housing.

19. The method of claim 16, wherein as the permeability of the barrier increases, the ratio between the area of the barrier to the area of the perforated screen increases.

20. The method of claim 16, wherein as the permeability of the barrier increases, the ratio between the area of the barrier to the area of a passage of fluid flow increases.