CN113167115A

CN113167115A - Compressed gas engine

Info

Publication number: CN113167115A
Application number: CN201980060134.3A
Authority: CN
Inventors: B·W·科尔
Original assignee: Air Technology Inc
Current assignee: Air Technology Inc
Priority date: 2018-07-16
Filing date: 2019-04-16
Publication date: 2021-07-23
Also published as: WO2020018161A1; US20210231111A1; EP3824161A1

Abstract

The invention provides a compressed gas engine. The compressed gas engine may include a first crankshaft, a first set of piston assemblies, a second set of piston assemblies, and a first valve assembly. The first set of piston assemblies may be coupled to the first crankshaft and include a first piston assembly having a first diameter and a second piston assembly having a second diameter. The second set of piston assemblies may be operably coupled to the first crankshaft and include a third piston assembly having a first diameter and a fourth piston assembly having a second diameter. The second set of piston assemblies may be located on the crankshaft opposite the first set of piston assemblies such that the piston assemblies of the first set of piston assemblies are aligned with the piston assemblies of the second set of piston assemblies that have the same diameter as the piston assemblies.

Description

Compressed gas engine

Cross Reference to Related Applications

This patent application claims the benefit of south african provisional patent application serial No. 2018/04722 filed 2018, 7, 16, 35USC 119 (e). South african provisional patent application serial No. 2018/04722 is incorporated herein by reference in its entirety.

Background

Compressed gas engines may be used as an alternative to internal combustion engines to provide rotational mechanical energy to various machines. However, compressed gas engines typically require highly compressed gas to match the energy content per unit mass contained in a combustible fuel such as gasoline. Furthermore, the operation of a typical compressed gas engine may result in a rapid decompression of the compressed gas, resulting in a significant drop in air temperature and possibly freezing of the compressed gas engine.

Disclosure of Invention

Certain embodiments of the invention may include a compressed gas engine. The compressed gas engine may include a first crankshaft, a first set of piston assemblies, a second set of piston assemblies, and a first valve assembly. The first set of piston assemblies may be coupled to the first crankshaft and include a first piston assembly having a first diameter and a second piston assembly having a second diameter. The second set of piston assemblies may be operably coupled to the first crankshaft and include a third piston assembly having a first diameter and a fourth piston assembly having a second diameter. The second set of piston assemblies may be located on the crankshaft opposite the first set of piston assemblies such that the piston assemblies of the first set of piston assemblies are aligned with the piston assemblies of the second set of piston assemblies that have the same diameter as the piston assemblies. The open-sided cavity of the first piston assembly may be fluidly coupled to and receive compressed air from a compressed air source. The rod side cavity of the second piston assembly may be fluidly coupled to the rod side cavity of the first piston assembly and receive partially expanded compressed air from the rod side cavity of the first piston assembly.

Certain embodiments of the invention may include operating a compressed gas engine. The method can comprise the following steps: compressed gas is flowed from a compressed gas source into a rod side cavity of a first piston assembly of a first set of piston assemblies, the first set of piston assemblies operatively coupled to the crankshaft, the first piston assembly having a first diameter. The method may further comprise: compressed gas is flowed from a compressed gas source into an open-sided cavity of a second piston assembly of a second set of piston assemblies operably coupled to the crankshaft opposite the first set of piston assemblies, the second piston assembly having a first diameter and aligned with the first piston assembly. The method may further comprise: the partially expanded compressed gas is forced from the open-sided cavity of the first piston assembly into an open-sided cavity of a third piston assembly of the first set of piston assemblies, the third piston assembly having a second diameter. The method may further comprise: the partially expanded compressed gas is forced from the rod side chamber of the second piston assembly into a rod side chamber of a fourth piston assembly of the second set of piston assemblies, the fourth piston assembly having the second diameter and being aligned with the third piston assembly.

Other aspects of the invention will become apparent from the following description and the appended claims.

Drawings

Embodiments of a compressed gas engine are described with reference to the following drawings. Throughout the drawings, the same reference numerals are used to designate similar features and components. The features depicted in the drawings are not necessarily shown to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of elements may not be shown in the interest of clarity and conciseness.

FIG. 1 is a schematic illustration of a compressed gas engine system according to one or more embodiments.

FIG. 2A is a schematic illustration of the engine module of FIG. 1 according to one or more embodiments.

FIG. 2B is a cross-sectional view of the engine module of FIG. 2A taken along line B-B.

3A-3E are schematic diagrams illustrating the flow of compressed gas through the engine module of FIG. 2A according to one or more embodiments.

FIG. 4 is a schematic illustration of an engine module according to one or more embodiments.

FIG. 5A is a schematic illustration of the compressed gas engine of FIG. 1 according to one or more embodiments.

Fig. 5B is a cross-sectional view of the compressed gas engine of fig. 5A taken along line B-B.

Fig. 6A-6J are schematic diagrams illustrating the flow of compressed gas through an engine module according to one or more embodiments.

Detailed Description

Specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following detailed description of embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well known features have not been described in detail to avoid unnecessarily complicating the description.

In the following description of fig. 1-6J, any component described with respect to a figure may be equivalent to one or more similarly-named components described with respect to any other figure, in various embodiments of the invention. For the sake of brevity, the description of these components will not be repeated for each figure. Thus, each embodiment of a component of each figure is incorporated by reference and is assumed to be optionally present within each other figure having one or more similarly named components. In addition, various embodiments according to the present invention may be implemented in addition to, in combination with, or instead of the embodiments described with respect to corresponding similarly-named components in any of the other figures.

Throughout this application, ordinal numbers (e.g., first, second, third, etc.) may be used as adjectives for elements (i.e., any noun in the application). Unless explicitly disclosed, the use of ordinal numbers does not necessarily imply or generate any particular order of elements, nor limit any elements to only a single element, such as by the use of the terms "before … …", "after … …", "single", and other such terms. Ordinals, instead, are used to distinguish elements. For example, a first element is different from a second element, and the first element may contain more than one element and may be subsequent to (or previous to) the second element in the order of the elements. Further, as used herein, the term "about," when used in conjunction with a target value, means within 10% of the target value.

The invention provides a compressed gas engine system. Compressed gas engine systems provide rotational energy to a rotating component, such as a generator, gearbox or pump. Compressed gas engine systems may also be used to provide rotational energy to other types of rotating components such as marine propellers, generators, and vehicle drive shafts. However, the rotating member is not limited to the above example.

FIG. 1 is a schematic illustration of a compressed gas engine system (100) according to one or more embodiments. Referring to fig. 1, a compressed gas engine system (100) includes a compressed gas engine (102) fluidly coupled to a compressed gas source (104) and a depressurized gas container (106), and operably coupled to one or more rotating components (108).

The compressed gas engine system (100) further comprises an engine management system (110) controlling the operation of the compressed gas engine (102). The engine management system (110) controls a valve assembly (not shown) for controlling the flow of compressed gas through the compressed gas engine (102). As discussed in more detail below, the valve assembly may include a spool valve or a solenoid valve. However, the present invention is not limited thereto. In other embodiments, the valve assembly may include other types of valves, such as ball valves, rotary valves, or other types of flow control valves. However, the valve is not limited to the above example.

The compressed gas engine (102) decompresses compressed gas received from the compressed gas source (104) in two or more stages, as discussed in more detail below, to provide rotational energy to the rotating component (108) via a drive shaft (112) or similar structure. The pressure reduction occurs in one or more engine modules (114, 116) that are operably coupled together to provide a single output to the rotating component (108). Although two engine modules (114, 116) are shown, the invention is not so limited. In other embodiments, the compressed gas engine (102) may include one, three, or more engine modules (114, 116).

After passing through the compressed gas engine (102), the depressurized gas is typically maintained at a pressure above ambient air pressure and is discharged into a depressurized gas vessel (106) for storage. The gas stored in the depressurized gas vessel (106) may then be compressed using less input energy than is required to compress the gas that powers the compressed gas engine system (100). Alternatively, the reduced pressure gas may be vented to atmosphere.

The compressed gas engine (102) may decompress compressed air, compressed nitrogen, or any other compressed gas to provide rotational energy to the rotating components (108). Alternatively, the compressed gas engine (100) may utilize liquefied gas, such as liquid nitrogen. In this case, however, the compressed gas engine system (100) comprises an expansion device (not shown) which heats the vaporized liquefied gas to ensure that the resulting compressed gas is at the appropriate temperature for the compressed gas engine (100).

Referring now to fig. 2A, fig. 2A is the engine module 114 of fig. 1 in accordance with one or more embodiments. The engine module 114 includes a plurality of piston assemblies (200A, 200B, 202A, 202B, 204A, 204B), each including a rod assembly (206) that divides an internal cavity (208) of the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) into an open-sided cavity (210) and a rod-sided cavity (212). The rod assembly (206) includes a rod (214) coupled to the piston (215) by a pivot (not shown) and extending through a rod side cavity (212) of the piston assembly (200A, 200B, 202A, 202B, 204A, 204B). The piston assembly (200A, 200B, 202A, 202B, 204A, 204B) further includes an open-side port (216) in fluid communication with the open-side cavity (210) and a rod-side port (218) in fluid communication with the rod-side cavity (212).

As shown in fig. 2A, the diameter of

piston assemblies

204A and 204B is greater than the diameter of

piston assemblies

202A and 202B, while the diameter of

piston assemblies

202A and 202B is greater than the diameter of

piston assemblies

200A and 200B. In at least one embodiment, the diameter of

piston assemblies

202A and 202B is in the range of 1.5 to 1.6 times the diameter of

piston assemblies

200A and 200B, and the diameter of

piston assemblies

204A and 204B is in the range of 1.5 to 1.6 times the diameter of

piston assemblies

202A and 202B. In other embodiments, the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) may have different sized diameters and/or diameter ratios.

The rod assembly (206) is coupled to the crankshaft (220) by a bearing assembly (222) that allows the crankshaft (220) to rotate within the bearing assembly (222). The piston assemblies are arranged in groups, i.e.,

piston assemblies

200A, 202A, and 204A or

piston assemblies

200B, 202B, and 204B, which are located on either side of a crankshaft (220) and aligned such that piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) having the same diameter are connected to the same portion of the crankshaft (220). This configuration allows the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) to rotate the crankshaft (220) as the rod assembly (206) extends and retracts.

Additionally, as shown in fig. 2B, the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) are arranged along the same plane, e.g., fig. 2B at the horizontal plane shown. In other embodiments, the plane may be vertical or any other orientation. The connection between the crankshaft (220) and the bearing assembly 220 of each adjacent piston assembly (200A, 200B, 202A, 202B, 204A, 204B) of the same piston assembly set (i.e.,

piston assemblies

200A, 202A, and 204A or

piston assemblies

200B, 202B, and 204B) is radially offset 180 degrees.

Referring again to fig. 2A, the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) and the crankshaft (220) are supported by an engine frame (224) that maintains the relative positions of the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) and the crankshaft 220. The engine frame (224) includes a plurality of bearings (226) that support the crankshaft (220) while allowing the crankshaft (220) to rotate within the engine frame (224). The engine module (114) also includes two spool valves (228A, 228B) that control the flow of air through the engine module (114), as described in more detail with reference to fig. 3A-3E and 6A-6J.

Referring now to fig. 3A-3E, fig. 3A-3E are schematic diagrams illustrating the flow of compressed gas through the engine module (114) of fig. 2A according to one or more embodiments. As shown in fig. 3A, the spool valves (228A, 228B) are actuated to a first position, allowing compressed gas to flow from the compressed gas source (104) to the rod side port (218) of the piston assembly 200A and the port side port (216) of the piston assembly 200B, respectively. This allows compressed gas to enter the rod side chamber (212) of the piston assembly 200A and the open side chamber (210) of the piston assembly 200B, thereby partially expanding the compressed gas, retracting the rod assembly (206) of the piston assembly 200A, and extending the rod assembly (206) of the piston assembly 200B. Movement of each rod assembly (206) rotates the crankshaft (220) to the position shown in fig. 3A, while the pivotal connection with the piston (215) and bearing assembly (222) allows the rod assembly (206) to pivot as the rod assembly (206) extends and retracts.

The spool valves (228A, 228B) are then actuated to a second position, allowing compressed gas to flow from the compressed gas source (104) to the open side port (216) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B, as shown in fig. 3B. This allows compressed gas to enter the open side chamber (210) of the piston assembly 200A and the rod side chamber (212) of the piston assembly 200B, thereby extending the rod assembly (206) of the piston assembly 200A and retracting the rod assembly (206) of the piston assembly 200B.

The movement of each rod assembly (206) also forces partially expanded compressed gas within the rod side chamber (212) of the piston 200A through the spool valve 228A and into the rod side chamber (212) of the piston 202A through the rod side port (218), and forces partially expanded compressed gas within the port side chamber (210) of the piston 200B through the spool valve 228B and into the port side chamber (210) of the piston 202B through the port side port (216). The displacement of the

piston assemblies

200A, 200B, 202A, 202B to the position shown in fig. 3B rotates the crankshaft (220) 180 degrees from the previous position shown in fig. 3A.

The spool valves (228A, 228B) are then actuated back to the first position, as shown in fig. 3C, allowing compressed gas to re-enter the rod side cavity (212) of the piston assembly 200A and the port side cavity (210) of the piston assembly 200B.

Compressed gas entering the piston assembly 200A retracts the rod assembly (206) and forces partially compressed gas within the open-sided cavity (210) of the piston assembly 200A through the spool valve 228A and through the open-sided port (216) into the open-sided cavity (210) of the piston 202A, thereby extending the rod assembly (206) of the piston assembly 202A. Movement of the rod assembly (206) of the piston assembly 202A in turn forces further expanding compressed gas within the rod side cavity (212) of the piston 202A through the spool valve 228A and into the rod side cavity (212) of the piston 204A through the rod side port (218), thereby retracting the rod assembly (206) of the piston assembly 204A.

When this occurs, compressed gas entering piston assembly 200B extends rod assembly (206) and forces a portion of the compressed gas within rod side cavity (212) of piston assembly 200B through spool valve 228B and through rod side port (218) into rod side cavity (212) of piston 202A, thereby retracting rod assembly (206) of piston assembly 202B. Retraction of the rod assembly (206) of the piston assembly 202B forces further expanded compressed gas within the open-sided cavity (210) of the piston 202B through the spool valve 228B and through the open-sided port (216) into the open-sided cavity (210) of the piston 204B, thereby extending the rod assembly (206) of the piston assembly 204B. Displacement of the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) to the position shown in fig. 3C rotates the crankshaft (220) 180 degrees from the previous position shown in fig. 3B.

The spool valves (228A, 228B) are then actuated to a second position, as shown in fig. 3D, allowing compressed gas to re-enter the port-side cavity (210) of the piston assembly 200A and the rod-side cavity (212) of the piston assembly 200B.

Compressed gas entering piston assembly 200A extends rod assembly (206) and forces a portion of the compressed gas within rod side cavity (212) of piston assembly 200A through spool valve 228A and through rod side port (218) into rod side cavity (212) of piston 202A, thereby retracting rod assembly (206) of piston assembly 202A. Movement of the rod assembly (206) of the piston assembly 202A in turn forces further expanding compressed gas within the open-sided cavity (210) of the piston 202A through the spool valve 228A and into the open-sided cavity (210) of the piston 204A through the open-sided port (216), thereby extending the rod assembly (206) of the piston assembly 204A. Movement of the rod assembly (206) of the piston assembly 204A causes the reduced-pressure gas within the rod-side cavity (212) of the piston assembly 204A to be discharged into the reduced-pressure gas reservoir (106).

When this occurs, compressed gas entering the piston assembly 200B retracts the rod assembly (206) and forces a portion of the compressed gas within the open-sided cavity (210) of the piston assembly 200B through the spool valve 228B and through the open-sided port (216) into the open-sided cavity (210) of the piston 202B, thereby extending the rod assembly (206) of the piston assembly 202B. Movement of rod assembly (206) of piston assembly 202B in turn forces further expanding compressed gas within rod side cavity (212) of piston 202B through spool valve 228B and into rod side cavity (212) of piston 204B through rod side port (218), thereby retracting rod assembly (206) of piston assembly 204B. Movement of the rod assembly (206) of the piston assembly 204B causes the reduced-pressure gas within the open-sided cavity (210) of the piston assembly 204B to be discharged into the reduced-pressure gas reservoir (106). Displacement of the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) to the position shown in fig. 3D rotates the crankshaft (220) 180 degrees from the previous position shown in fig. 3C.

As previously described, the reduced-pressure gas entering the reduced-pressure gas vessel (106) may still be at a pressure above ambient pressure, for example, the gas may initially be at 200psi, reduced to 100psi in the

piston assemblies

200A and 200B, further reduced to 50psi in the

piston assemblies

202A and 202B, and finally reduced to 25psi in the

piston assemblies

204A and 204B. In other embodiments, the compressed gas source (104) may be at a pressure other than 200psi, or the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) may decompress the compressed gas to a different pressure.

The spool valves (228A, 228B) are then actuated to a first position, as shown in fig. 3E, allowing compressed gas to re-enter the rod side cavity (212) of the piston assembly 200A and the port side cavity (210) of the piston assembly 200B.

Compressed gas entering the piston assembly 200A retracts the rod assembly (206) and forces partially compressed gas within the open-sided cavity (210) of the piston assembly 200A through the spool valve 228A and through the open-sided port (216) into the open-sided cavity (210) of the piston 202A, thereby extending the rod assembly (206) of the piston assembly 202A. Movement of the rod assembly (206) of the piston assembly 202A in turn forces further expanding compressed gas within the rod side cavity (210) of the piston 202A through the spool valve 228A and into the rod side cavity (212) of the piston 204A through the rod side port (218), thereby retracting the rod assembly (206) of the piston assembly 204A. Movement of the rod assembly (206) of the piston assembly 204A causes the reduced-pressure gas within the open-sided cavity (210) of the piston assembly 204A to be discharged into the reduced-pressure gas reservoir (106).

When this occurs, compressed gas entering piston assembly 200B extends rod assembly (206) and forces a portion of the compressed gas within rod side cavity (212) of piston assembly 200B through spool valve 228B and through rod side port (218) into rod side cavity (212) of piston 202B, thereby retracting rod assembly (206) of piston assembly 202B. Movement of the rod assembly (206) of the piston assembly 202B in turn forces further expanding compressed gas within the open-sided cavity (210) of the piston 202B through the spool valve 228B and through the open-sided port (216) into the open-sided cavity (210) of the piston 204B, thereby extending the rod assembly (206) of the piston assembly 204B. Movement of the rod assembly (206) of the piston assembly 204B causes the reduced-pressure gas within the rod-side cavity (212) of the piston assembly 204B to be discharged into the reduced-pressure gas reservoir (106). Displacement of the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) to the position shown in fig. 3E rotates the crankshaft (220) 180 degrees from the previous position shown in fig. 3D.

Once the compressed gas engine (102) reaches the stage shown in fig. 3E, the spool valves (228A, 228B) alternate between the first and second positions, as shown in fig. 3D and 3E. As compressed gas from the compressed gas source is depressurized in the compressed gas engine, displacement of the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) continues to rotate the crankshaft (220).

The use of multiple piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) allows the compressed gas to be gradually depressurized as it passes through the compressed gas engine 114. This prevents a sudden drop in gas temperature that could cause the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) to freeze. Additionally, the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) are sized such that the force applied to the crankshaft (220) by extension and retraction of the rod assembly (206) is approximately equal for each piston in the piston set. This allows additional energy to be extracted from the compressed gas as it is depressurized and increases the torque that can be provided by the crankshaft (220) to the rotating components (108).

Referring now to FIG. 4, FIG. 4 is a schematic diagram of an engine module 400 according to one or more embodiments. The engine module 400 functions similarly to the engine module 114 described above with reference to fig. 3A-3E. However, the spool valves (228A, 228B) have been replaced with solenoid valves (402, 404, 406, 408, 410, 414, 416, 418, 420, 422, 424). Specifically, each piston assembly (200A, 200B, 202A, 202B, 204A, 204B) includes an open-side inlet solenoid valve (402, 404, 406), an open-side outlet solenoid valve (408, 410), a rod-side inlet solenoid valve (414, 416, 418), and a rod-side outlet solenoid valve (420, 422, 424).

As shown in fig. 4, the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) are directly connected to each other by inlet solenoid valves (404, 406, 416, 418) and outlet solenoid valves (408, 410, 420, 422). Additionally, the

piston assemblies

200A and 200B are directly connected to the compressed gas source (104) through the inlet solenoid valve 402, and the

piston assemblies

204A and 204B are directly connected to the reduced pressure gas reservoir (106) through the outlet solenoid valve 424. The solenoid valves are actuated by the engine management system (110) to allow compressed gas to enter each of the chambers (210), (212), thereby allowing the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) to rotate the crankshaft (220) as described above.

In one or more embodiments, the

inlet solenoid valves

404, 406, 416, 418 may be fluidly connected to a junction having one side fluidly connected to each

outlet solenoid valve

408, 410, 420, 422 and another side fluidly connected to a second solenoid valve (426) fluidly connected to the compressed gas source (104). This configuration allows the engine management system (110) to increase the output torque of the compressed gas engine (102) by supplementing the portion of the depressurized gas flowing into the

piston assemblies

202A, 202B, 204A, 204B with compressed gas from the compressed gas source (104).

Referring now to fig. 5A, fig. 5A is a schematic illustration of the compressed gas engine (102) of fig. 1, according to one or more embodiments. The individual engine modules (114, 116) of the compressed gas engine (102) are similar to those described above with reference to fig. 2A to 3E. However, the

crankshafts

220A and 220B of the

engine modules

114 and 116, respectively, are operatively coupled together to allow the crankshafts (220A, 220B) to rotate as a single unit. In some embodiments, the adjacent ends of the crankshafts (220A, 220B) are toothed to allow the crankshafts (220A, 220B) to rotate as a unit. In other embodiments, the crankshafts (220A, 220B) act as a single unit with a mechanically faster device or other similar device. In at least one embodiment, a single crankshaft (not shown) extends through both engine modules (114, 116).

The connections between adjacent piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the same piston assembly group (i.e.,

piston assemblies

200A, 202A, and 204A or

piston assemblies

200B, 202B, and 204B) and the respective crankshafts (220A, 220B) are radially offset by 180 degrees as described above. However, as shown in fig. 5B, the connection between the crankshafts (220A, 220B) is such that the connection between the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the engine module 114 and the crankshaft (220A) is radially offset by 90 degrees from the connection between the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the engine module 116 and the crankshaft (220B).

The 90 degree offset between the crankshafts (220A, 220B) causes the rod assembly (206) of one engine module (114, 116) to extend and retract while the rod assembly (206) of the other engine module (114, 116) is in a central position, as shown in fig. 5A. This arrangement helps prevent hydraulic lock-up of the compressed gas engine (102).

Referring now to fig. 6A-6J, fig. 6A-6J are schematic diagrams illustrating the flow of compressed gas through the compressed gas engine module (102) of fig. 6A according to one or more embodiments. As shown in fig. 6A, the spool valves (600A, 600B) are actuated to a first position, allowing compressed gas to flow from the compressed gas source (104) to the rod side port (218) of the piston assembly 200A and the opening side port (216) of the piston assembly 200B of the engine module 114. This retracts the rod assembly (206A) of the piston assembly 200A and extends the rod assembly (206A) of the piston assembly 200B. Movement of each rod assembly (206A) rotates the crankshafts (220A, 220B) to the position shown in fig. 6A.

The spool valves (600A, 600B) are then actuated to a second position, as shown in fig. 6B, allowing compressed gas to enter the rod side port (218) of the piston assembly 200A and the opening side port (216) of the piston assembly 200B of the engine module 116. When this occurs, compressed gas flows from the compressed gas source (104) to the open side port (216) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B of the engine block 114. This extends the rod assembly (206A) of the piston assembly 200A and retracts the rod assembly (206) of the piston assembly 200B of the engine module 114.

Flowing compressed gas into the

piston assemblies

200A and 200B of the engine block 114 also forces partially expanded compressed gas within the rod side cavity (212) of the piston 200A into the rod side port (218) and partially expanded compressed gas within the port side cavity (210) of the piston 200B into the port side cavity of the piston 202B through the port side port (216) of the engine block 114, thereby displacing the rod assembly (206A) to a center position. The displacement of the

piston assemblies

200A, 200B, 202A, 202B of the engine module 114 and the

piston assemblies

200A and 200B of the engine module 116 to the position shown in FIG. 6B rotates the crankshafts (220A, 220B) 90 degrees from the previous position shown in FIG. 6A.

Then, as shown in fig. 6C, the spool valves (600A, 600B) are actuated to a third position, thereby continuing to flow compressed gas to the open side port (216) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B of the engine module 114. When this occurs, compressed gas also flows from the compressed gas source (104) to the open side port (216) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B of the engine block 116.

Flowing compressed gas into the

piston assemblies

200A and 200B of the engine module 116 also forces partially expanded compressed gas within the rod side cavities (212) of the piston assemblies 200A into the rod side ports (218) of the piston assemblies 202A and forces partially expanded compressed gas within the open side cavities (210) of the piston assemblies 200B of the engine module 116 into the open side ports (210) of the piston assemblies 202B of the engine module 114, thereby displacing the rod assemblies (206B) to a center position. The displacement of the

piston assemblies

200A, 200B, 202A, 202B of the engine module 114 and the

piston assemblies

200A and 200B of the engine module 116 to the position shown in fig. 6C rotates the crankshafts (220A, 220B) 90 degrees from the previous position shown in fig. 6B.

The

spool valves

600A, 600B are then actuated to a fourth position, as shown in fig. 6D, thereby continuing to flow compressed gas to the open side port (216) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B of the engine module 116. When this occurs, compressed gas also flows from the compressed gas source (104) to the rod side port (218) of the piston assembly 200A and the port side port (216) of the piston assembly 200B of the engine block 114.

Flowing compressed gas into the

piston assemblies

200A and 200B of the engine module 114 also forces partially expanded compressed gas within the open-sided cavity (210) of the piston assembly 200A of the engine module 114 into the open-sided port (216) of the piston assembly 202A and forces partially expanded compressed gas within the rod-sided cavity (212) of the piston assembly 202A of the engine module 114 into the rod-sided port (218) of the piston assembly 204A of the engine module 114.

Simultaneously, partially expanded compressed gas within the rod side cavity (212) of the piston assembly 200B of the engine module 114 is forced into the rod side port (212) of the piston assembly 202B of the engine module 114 and partially expanded compressed gas within the port side cavity (210) of the piston assembly 202B of the engine module 114 is forced into the port side port (216) of the piston assembly 204B. The displacement of the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the engine module 114 and the

piston assemblies

200A, 200B, 202A, 202B of the engine module 116 to the position shown in fig. 6D rotates the crankshafts (220A, 220B) 90 degrees from the previous position shown in fig. 6C.

The spool valves (600A, 600B) are then actuated back to the first position, as shown in fig. 6E, continuing to flow compressed gas to the rod side port (218) of the piston assembly 200A and the port side port (216) of the piston assembly 200B of the engine module 114. When this occurs, compressed gas also flows from the compressed gas source (104) to the rod side port (218) of the piston assembly 200A and the port side port (216) of the piston assembly 200B of the engine block 116.

Flowing compressed gas into the

piston assemblies

200A and 200B of the engine module 116 also forces a portion of the expanded compressed gas within the open-side cavities (210) of the piston assemblies 200A into the open-side ports (216) of the piston assemblies 202A and forces a portion of the expanded compressed gas within the rod-side cavities (212) of the piston assemblies 202A of the engine module 116 into the rod-side ports (212) of the piston assemblies 204A of the engine module 116.

Simultaneously, partially expanded compressed gas within the rod side cavity (212) of the piston assembly 200B of the engine block 116 is forced into the rod side port (212) of the piston assembly 202B, and partially expanded compressed gas within the port side cavity (210) of the piston assembly 202B of the engine block 116 is forced into the port side port (216) of the piston assembly 204B. Displacement of the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the engine modules (114, 116) to the position shown in fig. 6E rotates the crankshafts (220A, 220B) 90 degrees from the previous position shown in fig. 6D.

The spool valves (600A, 600B) are then actuated to a second position, as shown in fig. 6F, thereby continuing to flow compressed gas to the rod side port (218) of the piston assembly 200A and the port side port (216) of the piston assembly 200B of the engine module 116. When this occurs, compressed gas also flows from the compressed gas source (104) to the open side port (216) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B of the engine block 114.

This movement also forces partially expanded compressed gas within the rod side cavity (212) of the piston assembly 200A of the engine module 114 into the rod side port (218) of the piston assembly 202A and forces partially expanded compressed gas within the open side cavity (210) of the piston assembly 202A of the engine module 114 into the open side port (216) of the piston assembly 204A of the engine module 114. The depressurized gas within the rod side cavity (212) of the piston assembly 204A of the engine module 114 is then discharged into the depressurized gas reservoir (106).

Simultaneously, partially expanded compressed gas within the open-side cavity (210) of the piston assembly 200B of the engine module 114 is forced into the open-side port (216) of the piston assembly 202B, and partially expanded compressed gas within the rod-side cavity (212) of the piston assembly 202B of the engine module 114 is forced into the rod-side port (218) of the piston assembly 204B. The depressurized gas within the open-sided cavity (210) of the piston assembly 204B of the engine module 114 is then discharged into the depressurized gas container (106). Displacement of the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the engine modules (114, 116) to the position shown in fig. 6F rotates the crankshafts (220A, 220B) 90 degrees from the previous position shown in fig. 6E.

The spool valves (600A, 600B) are then actuated to a third position, as shown in fig. 6G, thereby continuing to flow compressed gas to the opening side port (218) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B of the engine module 114. When this occurs, compressed gas also flows from the compressed gas source (104) to the open side port (216) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B of the engine block 116.

This movement also forces partially expanded compressed gas within the rod side cavity (218) of the piston assembly 200A of the engine module 116 into the rod side port (218) of the piston assembly 202A and forces partially expanded compressed gas within the port side cavity (210) of the piston assembly 202A of the engine module 116 into the port side port (210) of the piston assembly 204A. The depressurized gas within the rod side cavity (212) of the piston assembly 204A of the engine module 116 is then discharged into the depressurized gas reservoir (106).

Simultaneously, partially expanded compressed gas within the open-side cavity (210) of the piston assembly 200B of the engine module 116 is forced into the open-side port (216) of the piston assembly 202B of the engine module 116, and partially expanded compressed gas within the rod-side cavity (212) of the piston assembly 202B of the engine module 116 is forced into the rod-side port (218) of the piston assembly 204B. The depressurized gas within the open-sided cavity (210) of the piston assembly 204B of the engine module 116 is then discharged into the depressurized gas container (106). Displacement of the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the engine modules (114, 116) to the position shown in fig. 6G rotates the crankshafts (220A, 220B) 90 degrees from the previous position shown in fig. 6F.

The spool valves (600A, 600B) are then actuated to a fourth position, as shown in fig. 6H, thereby continuing to flow compressed gas to the open side port (216) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B of the engine module 116. When this occurs, compressed gas also flows from the compressed gas source (104) to the rod side port (218) of the piston assembly 200A and the port side port (216) of the piston assembly 200B of the engine block 114.

This movement also forces partially expanded compressed gas within the open-side cavity (210) of the piston assembly 200A of the engine module 114 into the open-side port (216) of the piston assembly 202A and forces partially expanded compressed gas within the rod-side cavity (212) of the piston assembly 202A of the engine module 114 into the rod-side port (218) of the piston assembly 204A. The depressurized gas within the open-sided cavity (210) of the piston assembly 204A of the engine module 114 is then discharged into the depressurized gas container (106).

Simultaneously, partially expanded compressed gas within the rod side cavity (212) of the piston assembly 200B of the engine block 114 is forced into the rod side port (218) of the piston assembly 202B, and partially expanded compressed gas within the port side cavity (210) of the piston assembly 202B of the engine block 114 is forced into the port side port (216) of the piston assembly 204B. The depressurized gas within the rod side cavity (212) of the piston assembly 204B of the engine module 114 is then discharged into the depressurized gas reservoir (106). Displacement of the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the engine modules (114, 116) to the position shown in fig. 6H rotates the crankshafts (220A, 220B) 90 degrees from the previous position shown in fig. 6G.

The spool valves (600A, 600B) are then actuated to a fourth position, as shown in fig. 6I, thereby continuing to flow compressed gas to the rod side port (218) of the piston assembly 200A and the port side port (216) of the piston assembly 200B of the engine module 114. When this occurs, compressed gas also flows from the compressed gas source (104) to the rod side port (218) of the piston assembly 200A and the port side port (216) of the piston assembly 200B of the engine block 116.

This movement also forces partially expanded compressed gas within the open-side cavity (210) of the piston assembly 200A of the engine module 116 into the open-side port (216) of the piston assembly 202A and forces partially expanded compressed gas within the rod-side cavity (212) of the piston assembly 202A of the engine module 116 into the rod-side port (218) of the piston assembly 204A. The depressurized gas within the open-sided cavity (210) of the piston assembly 204A of the engine module 116 is then discharged into the depressurized gas container (106).

Simultaneously, partially expanded compressed gas within the rod side cavity (212) of the piston assembly 200B of the engine module 116 is forced into the rod side port (218) of the piston assembly 202B of the engine module 116, and partially expanded compressed gas within the port side cavity (210) of the piston assembly 202B of the engine module 116 is forced into the port side port (216) of the piston assembly 204B. The depressurized gas within the rod side cavity (212) of the piston assembly 204B of the engine module 116 is then discharged into the depressurized gas reservoir (106). Displacement of the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the engine modules (114, 116) to the position shown in fig. 6I rotates the crankshafts (220A, 220B) 90 degrees from the previous position shown in fig. 6H.

The spool valves (600A, 600B) are then actuated to a fourth position, as shown in fig. 6J, thereby continuing to flow compressed gas to the rod side port (218) of the piston assembly 200A and the port side port (216) of the piston assembly 200B of the engine module 116. When this occurs, compressed gas also flows from the compressed gas source (104) to the open side port (216) of the piston assembly 200A and the rod side port (218) of the piston assembly 200B of the engine block 114.

Simultaneously, partially expanded compressed gas within the open-side cavity (210) of the piston assembly 200B of the engine module 114 is forced into the open-side port (216) of the piston assembly 202B of the engine module 114, and partially expanded compressed gas within the rod-side cavity (212) of the piston assembly 202B of the engine module 114 is forced into the rod-side port (218) of the piston assembly 204B. The depressurized gas within the open-sided cavity (210) of the piston assembly 204B of the engine module 114 is then discharged into the depressurized gas container (106). The displacement of the piston assemblies (200A, 200B, 202A, 202B, 204A, 204B) of the engine modules (114, 116) to the position shown in fig. 6J rotates the crankshafts (220A, 220B) 90 degrees from the previous position shown in fig. 6I.

Once the compressed gas engine (102) reaches the stage shown in fig. 6J, the slide valves (600A, 600B) alternate between the first position, the second position, the third position, and the fourth position, as shown in fig. 6G-6J. As compressed gas from the compressed gas source is depressurized in the compressed gas engine, displacement of the piston assembly (200A, 200B, 202A, 202B, 204A, 204B) continues to rotate the crankshaft (220A, 220B).

One or more specific embodiments of a compressed gas engine system have been described. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

Claims

1. A compressed gas engine comprising:

a first engine module comprising:

a first crankshaft;

a first set of piston assemblies operably coupled to the first crankshaft and including a first piston assembly having a first diameter and a second piston assembly having a second diameter;

a second set of piston assemblies operably coupled to the first crankshaft and including a third piston assembly having the first diameter and a fourth piston assembly having the second diameter, the second set of piston assemblies being located on the crankshaft opposite the first set of piston assemblies such that the piston assemblies of the first set of piston assemblies are aligned with the piston assemblies of the second set of piston assemblies that are the same diameter as the piston assemblies; and

a first valve assembly fluidly coupled to the first set of pistons and the second set of pistons and configured to control a flow of compressed air through the first engine module; and is

Wherein:

the open-sided cavity of the first piston assembly is fluidly coupled to and receives compressed air from a compressed air source; and is

The rod side cavity of the second piston assembly is fluidly coupled to the rod side cavity of the first piston assembly and receives partially expanded compressed air from the rod side cavity of the first piston assembly.

2. The compressed air engine of claim 1, wherein the second diameter is greater than the first diameter.

3. The compressed air engine of claim 1, wherein adjacent piston assemblies within the same set of piston assemblies are connected to the crankshaft at points that are radially offset from each other by 180 degrees.

4. The compressed air engine of claim 1, wherein the first valve assembly comprises at least one of a plurality of spool valves or a plurality of solenoid valves.

5. The compressed gas engine of claim 1, wherein:

the rod side cavity of the first piston assembly is fluidly coupled to and receives compressed air from the compressed air source; and is

The open side cavity of the second piston assembly is fluidly coupled to the open side cavity of the first piston assembly and receives partially expanded compressed air from the open side cavity of the first piston assembly.

6. The compressed gas engine of claim 5, wherein:

an open-sided cavity of the third piston assembly is fluidly coupled to and receives compressed air from the compressed air source; and is

The rod side cavity of the fourth piston assembly is fluidly coupled to the rod side cavity of the third piston assembly and receives partially expanded compressed air from the rod side cavity of the third piston assembly.

7. The compressed gas engine of claim 6, wherein:

the rod side cavity of the third piston assembly is fluidly coupled to and receives compressed air from the compressed air source; and is

The open side cavity of the fourth piston assembly is fluidly coupled to the open side cavity of the third piston assembly and receives partially expanded compressed air from the open side cavity of the third piston assembly.

8. The compressed gas engine of claim 5, wherein:

the rod side cavity of the second piston assembly is fluidly coupled to and receives compressed air from the compressed air source; and is

The open-sided cavity of the second piston assembly is fluidly coupled to and receives compressed air from the compressed air source.

9. The compressed gas engine of claim 1, wherein:

the first set of piston assemblies further includes a fifth piston assembly having a third diameter; and is

The second set of piston assemblies includes a sixth piston assembly having the third diameter.

10. The compressed gas engine of claim 9, wherein a rod side cavity of the fifth piston assembly is fluidly coupled to the rod side cavity of the second piston assembly and receives further expanded compressed air from the rod side cavity of the second piston assembly.

11. The compressed air engine of claim 10, wherein the rod side cavity of the fifth piston assembly is fluidly coupled to a reduced pressure air reservoir and discharges reduced pressure air to the reduced pressure air reservoir.

12. The compressed gas engine of claim 9, wherein the open side cavity of the fifth piston assembly is fluidly coupled to the open side cavity of the second piston assembly and receives further expanded compressed air from the open side cavity of the second piston assembly.

13. The compressed air engine of claim 12, wherein the open-sided cavity of the fifth piston assembly is fluidly coupled to a reduced-pressure air reservoir and discharges reduced-pressure air to the reduced-pressure air reservoir.

14. The compressed gas engine of claim 1, further comprising a second engine module, the second engine module comprising:

a second crankshaft operably coupled to the first crankshaft; and

a third set of piston assemblies operably coupled to the second crankshaft and including a fifth piston assembly having the first diameter and a sixth piston assembly having the second diameter;

a fourth set of piston assemblies operably coupled to the second crankshaft and including a seventh piston assembly having the first diameter and an eighth piston assembly having the second diameter, the fourth set of piston assemblies being located on the crankshaft opposite the third set of piston assemblies such that the piston assemblies of the third set of piston assemblies are aligned with the piston assemblies of the fourth set of piston assemblies that are the same diameter as the piston assemblies of the fourth set of piston assemblies; and

a second valve assembly fluidly coupled to the third and fourth sets of pistons and configured to control a flow of compressed air through the second engine module.

15. The compressed gas engine of claim 14, wherein:

adjacent piston assemblies within the same set of piston assemblies are connected to the respective crankshafts at points radially offset from each other by 180 degrees; and is

The piston assemblies of the first and second sets of piston assemblies are connected to the first crankshaft at a point radially offset 90 degrees from a connection point between the second crankshaft and the piston assemblies of the third and fourth sets of piston assemblies.

16. A method of operating a compressed gas engine, the method comprising:

flowing compressed gas from a compressed gas source into a rod side cavity of a first piston assembly of a first set of piston assemblies, the first set of piston assemblies operatively coupled to a crankshaft, the first piston assembly having a first diameter;

flowing compressed gas from the compressed gas source into an open-sided cavity of a second piston assembly of a second set of piston assemblies operably coupled to the crankshaft opposite the first set of piston assemblies, the second piston assembly having the first diameter and aligned with the first piston assembly;

forcing partially expanded compressed gas from an open-sided cavity of the first piston assembly into an open-sided cavity of a third piston assembly of the first set of piston assemblies, the third piston assembly having a second diameter; and

forcing partially expanded compressed gas from the rod side chamber of the second piston assembly into a rod side chamber of a fourth piston assembly of the second set of piston assemblies, the fourth piston assembly having the second diameter and aligned with the third piston assembly.

17. The method of claim 16, wherein the second diameter is greater than the first diameter.

18. The method of claim 16, further comprising:

flowing compressed gas from the compressed gas source into the open-sided cavity of the first piston assembly;

flowing compressed gas from the compressed gas source into the rod side cavity of the second piston assembly;

forcing partially expanded compressed gas from the rod side chamber of the first piston assembly into a rod side chamber of the third piston assembly; and

forcing partially expanded compressed gas from the open-sided cavity of the second piston assembly into the open-sided cavity of the fourth piston assembly.

19. The method of claim 18, wherein:

the first set of piston assemblies further includes a fifth piston assembly having a third diameter;

the second set of piston assemblies further includes a sixth piston assembly having the third diameter and aligned with the fifth piston assembly;

the third diameter is greater than the second diameter;

the second diameter is greater than the first diameter; and is

The method further comprises the following steps:

forcing further expanded compressed gas from the open-sided chamber of the third piston assembly into an open-sided chamber of the fifth piston assembly; and

forcing further expanded compressed gas from the rod side chamber of the fourth piston assembly into the rod side chamber of the sixth piston assembly.

20. The method of claim 19, further comprising:

forcing further expanded compressed gas from the rod side chamber of the third piston assembly into a rod side chamber of the fifth piston assembly; and

forcing further expanded compressed gas from the open-sided cavity of the fourth piston assembly into the open-sided cavity of the sixth piston assembly.