CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application is a non-provisional application claiming the benefit of U.S. Provisional Application 62/078,046, filed November 11 , 2014, and U.S.

Provisional Application 61/994,579, filed May 16, 2014, U.S. Non-Provisional

Application 14/610,674, filed January 30, 2015, each of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention is generally directed to a fuel delivery system for an internal combustion engine. More specifically, it is directed to a fuel delivery system for delivering gaseous fuels from sorbent-based low pressure gaseous fuel storage systems to the fuel injection systems of an internal combustion engines.

BACKGROUND OF INVENTION

[0003] Sorbent-based gaseous fuel storage systems such as activated carbon sorbent storage of natural gas advantageously operate at lower pressures than non- sorbent systems. For example, sorbent storage systems operate at relatively low pressures in a range of about 10 psi (0.07 MPa) to about 1000 psi (7 MPa) compared to 3,600 psi (24.821 MPa) for conventional, non-sorbent systems for internal combustion engines. While the lower pressures associated with sorbent- based systems have the potential of being more readily utilized in applications such as motor vehicles due to the fact that the systems can be less robust, bulky, complicated, and costly than high pressure systems, there have been performance drawbacks that have hindered their acceptance. In particular, getting the adsorbed gaseous fuel out of a tank and delivered to the engine for combustion in a controlled and consistent manner has been a technical challenge.

[0004] One reason for the difficulty is due to the relatively low pressures involved, which is as the amount of fuel in a tank is drawn down during operation of the engine. Specifically, the release of adsorbed gaseous fuel is typically a linear relationship with tank pressure. Thus, as the fuel is drawn from the tank, the pressure decreases, which in turn decreases the tendency of fuel to be released. This decrease in pressure has been particularly challenging to operating internal combustion engines which can often require fuel pressures that exceed that of the gaseous fuel in the tank.

[0005] Additionally, the type of sorbent and/or type of gaseous fuel can affect the fuel release. In general, the more fuel a particular fuel-sorbent combination can accommodate, the stronger the adsorbtion of the fuel. The stronger the adsorbtion, the less likely the fuel may be consistently delivered to an engine, especially as the pressure decreases. This has tended to limit the selection of sorbents, in particular, the most effective sorbents.

[0006] Still further, because the typical modern conventional engines require gaseous fuel to be pressurized for injection into the engine (e.g., up to about 200 psi), a significant amount of fuel has remained essentially unusable/inaccessible in the tank.

[0007] In view of the foregoing, a need still exists for equipment and methods for extracting a gaseous fuel from a sorbent-based storage tank in a consistent and controlled manner over a wide range of tank pressures and/or fuel levels. Further, a need still exists for the consistent and controlled delivery of gaseous fuel extracted from a sorbent-based storage tank to the fuel injection system of an internal combustion engine over a wide range of tank pressures and/or fuel levels.

SUMMARY OF INVENTION

[0008] In one embodiment, the present invention is directed to a fuel extraction and pressurization system for delivering a gaseous fuel from a fuel storage system to a fuel injection system of an internal combustion engine, wherein the fuel storage system comprises a tank having an interior in which a sorbent is present and to which the gaseous fuel is adsorbed and wherein the gaseous fuel is at a tank pressure in a tank pressure range of about 1000 psi (7 MPa) to about 10 psi (0.07 MPa). The fuel extraction and pressurization system comprising an input in fluid connection with the interior of the tank of the fuel storage system and an output in fluid connection with the fuel injection system and comprising one or more vacuum and pressurization components, wherein during operation the one or more vacuum and pressurization components apply a vacuum to the interior of the tank to facilitate the extraction of the adsorbed gaseous fuel from the tank and compress the extracted gaseous fuel thereby providing compressed gaseous fuel at an output pressure and an output flow rate to the fuel injection system for the operation of the internal combustion engine at or about the stoichiometric air-fuel ratio for the gaseous fuel at any selected throttle position for the internal combustion engine, regardless of the tank pressure within the tank pressure range, wherein the one or more vacuum and pressurization components are selected from the group consisting of a vacuum pump, a compressor, or a vacuum pump and a compressor.

[0009] In another embodiment, the present invention is directed to a fuel system comprising:

(a) a fuel storage system that comprises a tank having an interior in which a

sorbent is present and to which the gaseous fuel is adsorbed and wherein the gaseous fuel is at a tank pressure in a tank pressure range of about 1000 psi (7 MPa) to about 10 psi (0.07 MPa);

(b) a fuel injection system of an internal combustion engine; and

(c) the above-described fuel extraction and pressurization system.

[0010] In yet another embodiment, the present invention is directed to a vehicle comprising the above-described fuel system.

[0011] In still another embodiment, the present invention is directed to a process of extracting a gaseous fuel from a fuel storage system and pressurizing the extracted gaseous fuel for delivery to a fuel injection system of an internal combustion engine, wherein the fuel storage system comprises a tank having an interior in which a sorbent is present and to which the gaseous fuel is adsorbed and wherein the gaseous fuel is at a tank pressure in a tank pressure range of about 1000 psi (7 MPa) to about 10 psi (0.07 MPa), the method comprising operating a fuel extraction and pressurization system having an input in fluid connection with the interior of the tank of the fuel storage system and an output in fluid connection with the fuel injection system and comprising one or more vacuum and pressurization

components, wherein during operation the one or more vacuum and pressurization components apply a vacuum to the interior of the tank to facilitate the extraction of the adsorbed gaseous fuel from the tank and compress the extracted gaseous fuel thereby providing compressed gaseous fuel at an output pressure and an output flow rate to the fuel injection system for the operation of the internal combustion engine at or about the stoichiometric air-fuel ratio for the gaseous fuel at any selected throttle position for the internal combustion engine, regardless of the tank pressure within the tank pressure range, wherein the one or more vacuum and pressurization components are selected from the group consisting of a vacuum pump, a compressor, or a vacuum pump and a compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic of fuel system comprising an embodiment of a sorbent-based low pressure gaseous fuel delivery system that comprises a fuel extraction and pressurization system comprising a vacuum pump and a compressor.

[0013] Figure 2 is a schematic of a fuel system comprising an embodiment of a direct connection sorbent-based low pressure gaseous fuel delivery system and an embodiment of an isolated connection sorbent-based low pressure gaseous fuel delivery system.

DETAILED DESCRIPTION OF INVENTION

[0014] One embodiment of the present invention is directed to a fuel extraction and pressurization system for delivering a gaseous fuel from a fuel storage system to a fuel injection system of an internal combustion engine. In another embodiment, the invention is directed to a process of extracting a gaseous fuel from a fuel storage system and pressurizing the extracted gaseous fuel for delivery to a fuel injection system of an internal combustion engine. Still further, another embodiment of the invention is directed to a fuel system comprising said fuel extraction and

pressurization system. In yet another embodiment, the invention is directed to a vehicle comprising said fuel system.

[0015] It should be noted that embodiments of the fuel extraction and pressurization system may be in the form of a collection of unassembled/unconnected/uninstalled components not ready to be operated so as to deliver fuel to an internal combustion engine or in the form of assembled/connected/installed components ready to be operated so as to deliver fuel to an internal combustion engine.

Fuel Storage System

[0016] The fuel storage system may be any appropriate sorbent-based system.

Referring to Figures 1 and 2, a fuel storage system 1 may comprise one or more tanks 2 having an interior (not indicated with a numeral) in which one or more types of sorbent 20 are present and to which the gaseous fuel (not shown) may be adsorbed. The sorbent(s) 20 may be any appropriate configuration with respect to the interior of the tank. For example, the sorbent(s) may be in the form of particles (e.g., of substantially uniform size, or a distribution or combination(s) of sizes), or may be a single piece essentially of a size corresponding to the tank interior, or may be a combination of relatively large pieces configured to generally correspond to the tank interior comprise particulate, which may be combined with particles to fill space not occupied by said relatively large pieces. The particular configuration of the sorbent within the tank and type(s) of sorbent (discussed below), along with the tank shape and construction may be selected to achieve one or more particular results such cost, maximization of packing, ease of manufacture, ease of incorporation in a particular vehicles, etc. all of take into account the end application (e.g., commercial vehicles, passenger vehicles, locomotive, shipping, etc.). Typically, the gaseous fuel is at a tank pressure in a tank pressure range of about 1000 psi (7 MPa) to about 10 psi (0.07 MPa).

Fuel

[0017] Any gaseous fuel (not shown) or combination of gaseous fuels may be used. In one embodiment, the gaseous fuel is selected from the group consisting of methane, ethane, propane, N-butane, l-pentane, N-pentane, N-hexane, nitrogen, and combinations thereof. In another embodiment, the gaseous fuel comprises methane. In yet another embodiment, the gaseous fuel is natural gas.

Sorbent

[0018] Any sorbent(s) appropriate for the selected fuel(s) may be used. In one embodiment, the sorbent is selected from the group consisting of activated carbon, metal-organic frameworks, and combinations thereof. In one embodiment, the sorbent comprises activated carbon. In another embodiment, the sorbent is activated carbon. In one embodiment, the sorbent is one or more types of activated carbon. In another embodiment, the sorbent comprises metal-organic frameworks. In yet another embodiment, the sorbent is one or more types of metal-organic framework.

[0019] Examples of appropriate activated carbons include those derived from plant origins, such as corn cob, hard woods, soft woods or other similar cellulose structure, or from other carbon rich origins, such as polymers or polymer based materials, and then activated through an alkali, acid, steam, pressure, heat or any combination thereof. Examples of appropriate metal-organic frameworks include those materials that are porous polymeric material, consisting of metal ions linked together by organic bridging ligands.

Fuel Injection System

[0020] Similarly, the fuel injection system (not shown) for the internal combustion engine may be any system appropriate for delivering the selected gaseous fuel(s) to the engine for combustion appropriate system. Typically, the gaseous fuel is delivered to the internal combustion engine at or about the stoichiometric air-fuel ratio for the gaseous fuel. Examples of commercially available fuel injection systems include Westport Innovation, Inc.'s WING™ Power System.

Fuel Extraction and Pressurization System

[0021] The fuel extraction and pressurization system (FEPS) 3 is in fluid connection with the interior of the tank of the fuel storage system and the fuel injection system. Fluid connections may be accomplished using any appropriate fuel lines 10, fittings, connectors, seals, valves 11 , washers, etc. As the name implies, the FEPS extracts fuel from the tank by application of a vacuum and increases the pressure of the extracted fuel for delivery to the internal combustion engine via the fuel injection system. The FEPS comprises one or more components that are selected and/or controllable so as to deliver the extracted and compressed gaseous fuel to the fuel injection system for the operation of the internal combustion engine at or about the stoichiometric air-fuel ratio for the gaseous fuel at any selected throttle position for the internal combustion engine, regardless of whether the tank pressure is less than that needed for delivery to the internal combustion engine.

[0022] More particularly, the FEPS has (i) an input 4 to be placed in fluid connection with the interior of the tank of the fuel storage system (and the sorbent 20 therein), and during operation applies a vacuum to the interior of the tank to facilitate the extraction of the adsorbed gaseous fuel from the tank and (ii) an output 5 from which the extracted gaseous fuel is provided to the fuel injection system (not shown) at a output flow rate and a output pressure appropriate for the particular internal combustion engine application. In one embodiment, the output flow rate is in a range of about 10 to about 1 ,200 grams per minute and the output pressure is in a range of about 10 psi (0.07 MPa) to about 200 psi (1.38 MPa).

[0023] The components of the fuel extraction and pressurization system may be selected from the group consisting of one or more vacuum pumps 6 and/or compressors 7 that provide a vacuum at the input in fluid connection with the tank(s) and an increase in pressure or compression at the output in fluid connection with the fuel injection system. Examples of commercially available vacuum pumps include the MINI J Series cylindrical venturi vacuum pump that is available from Vaccon Vacuum Products. In one embodiment, the compressor(s) is/are selected from the group consisting of a rotary scroll compressor, in-line reciprocating compressor, rotary screw compressor, rotary lobe compressor, rotary vane compressor, and combinations thereof. Examples of commercially available compressors of this nature include the Aspen Compressor BLDC Rotary Q-Series Compressors available from Aspen Compressor and the CT-17-700 radial turbo compressor available from Celeroton.

[0024] Typically, it is desirable to select the type(s) and number(s) of such

components that provide the desired functionality (e.g., degree of vacuum, output flow rate, and output pressure) reliably for as little cost and weight as is reasonable for the particular application. For example, reliability and capacity are more of a concern than cost and weight for heavy duty vehicle applications (e.g., vehicles having engine displacements in excess of 6.2 liters, such 15 liter spark ignited engines).

[0025] In one embodiment, the FEPS comprises a vacuum pump with its inlet in fluid connection with the fuel storage system and its outlet in fluid connection with the fuel injection system. In another embodiment (e.g., Figures 2 A and B), the FEPS 3 comprises a compressor 6 with its inlet 4 in fluid connection with the fuel storage system 1 and its outlet 5 in fluid connection with the fuel injection system (not shown). In yet another embodiment (e.g., Figure 1 ), the FEPS 3 comprises a vacuum pump 6 with its inlet 4 in fluid connection with the fuel storage system 1 and its outlet (not identified) in fluid connection with the inlet (not identified) of a compressor 7, with its outlet 5 in fluid connection with the fuel injection system (not shown).

[0026] The vacuum and pressurization components of the FEPS may be

independently operated by any appropriate supply of power/energy. For example, one or more of such components may be mechanically-operated, electrically- operated, pneumatically-operated, hydraulically-operated, or a combination thereof. In one embodiment, the vacuum and pressurization component(s) are electrically- operated.

[0027] Referring to Figures 2 A and B, the FEPS 3 and its fluid connection(s) may be "integral" with, or "isolated" from the fueling circuit. Specifically, in an "integral" or "direct connection" embodiment such as shown in Figure 2 A, fuel passes through the component(s) of the FEPS when the internal combustion engine is operated, regardless of whether the pressure within fuel storage system is sufficient for delivery of fuel to internal combustion engine. In contrast, in an "isolated"

embodiment such as shown in Figure 2 B, fuel only passes through the

component(s) of the FEPS when the pressure in the fuel storage system is at or below a specified pressure (e.g., 150 psi (1.034 MPa)). Thus, when the pressure in the fuel storage system decreases to the specified pressure the FEPS is placed in fluid connection with the fuel storage system and the fuel injection system and operated to apply a vacuum to the storage system and to adequately pressurize or compress the extracted fuel for delivery to the internal combustion engine via the fuel injection system. An "isolated" FEPS may be isolated and then placed in fluid connection through any appropriate device(s) and configuration(s). For example, as shown in Figure 2 B, a fuel circuit may comprise one or more pressure release valves 12 that keep the fuel extraction and pressurization system 3 "isolated" when the pressure in the fuel storage system 1 is above the specified pressure but when the pressure in the fuel storage system falls to the specified pressure, the pressure release valve(s) would operate (e.g., from being open to being closed or vice versa, depending upon the configuration of the fuel circuit) thereby placing the FEPS in fluid connection with the fuel storage tank and the fuel injection system.

Process

[0028] The present invention is also directed to a process of extracting a gaseous fuel from a fuel storage system and pressurizing the extracted gaseous fuel for delivery to a fuel injection system of an internal combustion engine, wherein the fuel storage system comprises a tank having an interior in which a sorbent is present and to which the gaseous fuel is adsorbed and wherein the gaseous fuel is at a tank pressure in a tank pressure range of about 1000 psi (7 MPa) to about 10 psi (0.0.689 MPa). The method comprises operating the fuel extraction and pressurization system comprising a vacuum pump, a compressor, or a combination of a vacuum pump and a compressor having (i) an input to be placed in fluid connection with the interior of the tank of the fuel storage system to apply a vacuum to the interior of the tank to facilitate the extraction of the adsorbed gaseous fuel from the tank and pressurize or compress the extracted gaseous fuel to an output pressure and an output flow rate. Additionally, the FEPS components (e.g., vacuum pump, compressor, or combination) are selected and/or controllable so as to deliver the compressed gaseous fuel to the fuel injection system for the operation of the internal combustion engine at any selected throttle position for the internal combustion engine, regardless of the tank pressure within the tank pressure range.

[0029] Having illustrated and described the principles of the present invention, it should be apparent to persons skilled in the art that the invention can be modified in arrangement and detail without departing from such principles.

[0030] Although the materials and methods of this invention have been described in terms of various embodiments and illustrative examples, it will be apparent to those of skill in the art that variations can be applied to the materials and methods described herein without departing from the concept, spirit and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.