1. Field of Art
The disclosure generally relates to the field of internal combustion engines. Specifically, this disclosure relates to rotary engines with pistons pivotally mounted on a rotating rotor.
2. Description of the Related Art
Internal combustion engines are used in a variety of different applications, ranging from automobiles to aircraft to lawn mowers. Traditional internal combustion engines are relatively energy inefficient, converting approximately 70% of the fuel's energy into waste heat. This waste heat leads to high operating temperatures which causes premature component failure.
Traditional piston-based internal combustion engines are also difficult to package in a compact form factor, as each piston requires a corresponding cylinder, intake and exhaust valves, sparkplug, and connecting rod. Finally, traditional piston-based internal combustion engines are susceptible to excess vibration and noise due to the fact that each piston reciprocates rapidly without being counterbalanced. Therefore, there is a need for an internal combustion engine that can be cooled more efficiently, can be packaged in a more compact form factor, and is less susceptible to vibration and noise.
Embodiments relate to a rotary internal combustion engine including a housing, a rotor, a plurality of wings, and a plurality of sealing structures. The housing extends longitudinally along a first axis and includes a cylindrical internal surface. The housing is formed with an intake port and an exhaust port. The rotor is positioned inside the housing to rotate about the first axis and includes a plurality of arms extending to the cylindrical internal surface. Each of the wings is attached to each of the arms to rotate with reference to the rotor along a second axis parallel to the first axis. Each of the sealing structures is mounted onto each of the wings. The sealing structure isolates a first space between the cylindrical internal surface and each of the wings from a second space between each of the wings and the rotor. Combustible gas is received in the first space through the intake port for ignition, and exhaust gas is discharged from the first space through the exhaust port.
In some embodiments, the rotary internal combustion engine encloses structures at both ends of the housing and configured to enclose the rotor and the wings within the housing.
In some embodiments, the enclosing structures include flat cylindrical end plates that are secured to each end of the housing.
In some embodiments, tubes are formed within the shell and the enclosing structures, the tubes configured to circulate cooling fluid to cool the rotary combustion engine.
In some embodiments, each arm of the rotor comprises a curved surface abuts the sealing structure of a corresponding wing. The curved surface has a radius of curvature corresponding to a distance from the second axis of the wing to a leading edge of the wing facing the surface. The sealing structure slides along the curved surface.
In some embodiments, each of the wings further includes an outer surface extending from the leading edge. The outer surface having a radius of curvature the same as the internal cylindrical surface.
In some embodiments, the sealing structure includes a first member, and a second member. The first member abuts the curved surface. The first member extends across a first length and has a first width shorter than the first length. The first member includes a first sub-member, a second sub-member and a first bridge. The first sub-member extends across the first length. The second sub-member extends across the first length in parallel to the first sub-member. The first bridge connects the first sub-member and the second sub-member. The bridge in conjunction with the second sub-member forms a cantilever structure to provide resilience to the first member in a direction of the width of the first member. The second member intersects with the first member to form an angle with respect to the first member. The second member has a second length and a second width shorter than the second length. The second member includes a third sub-member, a fourth sub-member and a second bridge. The third sub-member extends across the second length. The fourth sub-member extends across the second length in parallel to the third sub-member. The second bridge connects the third sub-member and the fourth sub-member. The second bridge in conjunction with the fourth sub-member forms a cantilever structure to provide resilience to the second member in a direction of the width of the second member.
In some embodiments, the rotary internal combustion engine further includes a sparkplug extending through a sparkplug hole formed in the housing.
In some embodiments, grooves are formed in the cylindrical internal surface of the shell extending from the sparkplug hole.
In some embodiments, the housing further includes a plurality of cooling fins extending outward from the housing.
In some embodiments, the rotary internal combustion engine further includes an enclosing structure attached to one end of the housing with the rotor and the wings enclosed in interior of the housing. A cam track is formed in the enclosing structure to constrain the rotation of the wings with reference to the rotor as the rotor rotates about the first axis.
In some embodiments, the cam track is isolated from the first space during the ignition of the combustible gas during the operation of the rotary internal combustion engine.
In some embodiments, each of the wings further includes a leading edge, a trailing edge section, an outer surface and an inner surface. The leading edge facing a corresponding arm of the rotor. The trailing edge section hinged to another arm of the rotor adjacent to the corresponding wing. The outer surface has a radius of curvature the same as the cylindrical inner surface of the shell and extending from the leading edge to the trailing edge section. The outer surface defines the first space in conjunction with the cylindrical internal surface. The inner surface extends from the leading edge to the trailing edge section. The inner surface defines the second space in conjunction with the rotor.
In some embodiments, the trailing edge section includes a trailing surface contacting the cylindrical internal surface. The trailing surface has a radius of curvature corresponding to a distance from the second axis to the cylindrical internal surface.
In some embodiments, each of the housing, rotor, and the wings are manufactured using an extrusion process.
Embodiments also relate to a sealing structure including a first member and a second member. The first member extends across a first length and has a first width shorter than the first length. The first member includes a first sub-member, a second sub-member and a first bridge. The first sub-member extends across the first length. The second sub-member extends across the first length in parallel to the first sub-member. The first bridge connects the first sub-member and the second sub-member. The bridge in conjunction with the second sub-member forms a cantilever structure to provide resilience to the first member in a direction of the width of the first member. The second member intersects with the first member to form an angle with respect to the first member. The second member has a second length and a second width shorter than the second length. The second member includes a third sub-member, a fourth sub-member and a second bridge. The third sub-member extends across the second length. The fourth sub-member extends across the second length in parallel to the third sub-member. The second bridge connects the third sub-member and the fourth sub-member. The second bridge in conjunction with the fourth sub-member forms a cantilever structure to provide resilience to the second member in a direction of the width of the second member.
In some embodiments, the second member includes a fifth sub-member that is received in a groove formed in a wing of a rotary internal combustion engine.
In some embodiments, the second member is curved in a direction perpendicular to the width of the second member.
Embodiments also relate to a method of operating a rotary internal combustion engine. A volume of a first space between a wing and an internal cylindrical surface of a housing is increased to receive combustible gas in the first space by rotating a rotor about a first axis within a housing. The volume of a second space between the wing and the rotor is decreased by rotating the wing about a second axis parallel to the first axis with the first space isolated from the second space by a sealing structure. The volume of the first space is decreased to compress the received combustible gas. The combustible gas received in the first space is ignited to exert force on the wing and form exhaust gas, responsive to decreasing the volume of the first space. The volume of the first space is increased responsive to igniting the combustible gas. The volume of the first space is decreased by rotating the wing about the second axis to discharge the exhaust gas from the first space, responsive to igniting the combustible gas. The volume of the second space is decreased by rotating the wing about the second axis with the first space isolated from the second space by the sealing structure.
In some embodiments, contact between a trailing edge section of the wing and the internal cylindrical surface is maintained during the rotation of the wing about the second axis.
The disclosed embodiments have advantages and features which will be more readily apparent from the detailed description, the appended claims, and the accompanying figures (or drawings). A brief introduction of the figures (Figs.) is below.
The Figures (Figs.) and the following description relate to preferred embodiments by way of illustration only. It should be noted that from the following discussion, alternative embodiments of the structures and methods disclosed herein will be readily recognized as viable alternatives that may be employed without departing from the principles of what is claimed.
Reference will now be made in detail to several embodiments, examples of which are illustrated in the accompanying figures. It is noted that wherever practicable similar or like reference numbers may be used in the figures and may indicate similar or like functionality.
Embodiments relate to a rotary internal combustion engine with a sealing structure that enables a rotor and a plurality of wings within a housing to form a plurality of sealed chambers. The wings can rotate about a first axis with reference to the rotor, and the rotor can rotate about a second axis with reference to the housing. The second axis is parallel to the first axis. As the rotor rotates within the housing, the wings follow a predefined path, causing the sealed chambers to increase or decrease in volume. Each sealed chamber acts as a combustion chamber in a conventional piston-based internal combustion engine and undergoes the intake, compression, power, and exhaust cycles of a four stroke engine. In some embodiments, the sealed chambers may undergo the cycles of a two stroke engine.
FIG. (FIG.) 1A illustrates an exploded perspective view of a rotary wing engine 105 according to one embodiment. The rotary wing engine 105 may include, among other components, an engine housing 110, end plates 115A and 115B (hereinafter collectively referred to as “end plates 115”), side covers 116A and 116B (hereinafter collectively referred to as “side plates 116”), a sparkplug 121, a rotor 135, a crankshaft 140, and a plurality of wing assemblies 145A through 145D (hereinafter collectively referred to as “the wing assemblies 145”). The rotary wing engine 105 has an overall cylindrical structure and may be utilized in any application that requires an internal combustion engine, such as an automobile. The rotary wing engine 105 outputs a rotational motion through the crankshaft 140. The crankshaft 140 may be connected to a driving mechanism, such as a transmission of an automobile, in order to power the automobile. In some embodiments, the crankshaft 140 may be connected to an electric motor of a hybrid drivetrain. In other embodiments, multiple rotary wing engines 105 may be stacked co-axially to increase the displacement and power output of the engine.
The wing assemblies 145 are coupled to the rotor 135 in such a way that each of the wing assemblies 145 can rotate about an axis with reference to the rotor 135, each axis parallel to the axis of the engine housing 110. The end plates 115 are secured to both ends of the engine housing 110, and the end plates 115 and engine housing 110 fully enclose the rotor 135 and wing assemblies 145. Each side cover 116 may be secured to each end plate 115. The rotor 135 is fixed to the crankshaft 140, and the rotor 135, wing assemblies 145, and crank shaft 140 can rotate about the axis of the engine housing 110 with reference to the engine housing 110 and end plates 115.
In this embodiment, the engine housing 110 is a cylindrical shell. The engine housing 110 extends longitudinally along an axis of the engine housing 110. The engine housing 110 houses the rotating components described above. The engine housing 110 may include, among others, an inner surface 111 and an outer surface 112. The inner surface 111 is cylindrical, and in some embodiments, the outer surface 112 may include features to mount the rotary wing engine 105 to a frame, for example, the frame of an automobile. In some embodiments, a sparkplug hole 120, an air intake 125, and an exhaust outlet 130 may be formed in the engine housing 110. The sparkplug hole 120 allows the sparkplug 121 to extend inside the rotary wing engine 105 to initiate a combustion, further described below in detail with reference to
The two end plates 115A and 115B are enclosing structures at both ends of the housing configured to enclose the rotor 135 and wing assemblies 145 within the engine housing 110. The end plates 115 may have the same outside diameter as the engine housing 110. The end plates 115 may be positioned to be concentric to the engine housing 110. The surface of each end plate 115 facing the engine housing 110 rests flush against the engine housing 110, forming an enclosed compartment comprising the engine housing 110 and the end plates 115.
One or both of end plates 115 may include a cam track 116. In some embodiments, the cam track 116 is a recessed groove formed in the flat surface of the end plate 115.
In this example embodiment, the end plates 115 are secured to the engine housing 110 by the use of threaded screws. In other embodiments, the end plates 115 may be secured to the engine housing 110 using a variety of other fasteners or adhesives. The end plates 115 are described in detail with reference to
The rotor 135 comprises a plurality of arms 410 arranged such that they are radially symmetric, and the rotor 135 can rotate within the engine housing 110 about the axis of the engine housing 110. The arms 410 extend from the center of the rotor 135 to the inner surface 111 of the engine housing 110, as described below in detail with reference to
The crankshaft 140 is cylindrical in shape and has a length equal to or greater than the combined depth of the engine housing 110 and end plates 115. One or both ends of the crankshaft 140 extend through a hole 305 (shown in
Each of the wing assemblies 145 is mounted to each of the arms 410 of the rotor 135. The wing assemblies 145 can rotate with reference to the rotor 135 about an axis that is parallel to the axis of the crankshaft 140. The wing assemblies 145 may include leading pin rollers 535A, 535B (shown in
The sparkplug 121 is a device that emits a spark when a voltage difference is applied across two electrical terminals. Sparkplugs are well known in the related field and detailed description thereof is omitted herein for the sake of brevity. The sparkplug 121 is secured inside the sparkplug hole 120 such that the sparkplug 121 completely seals the sparkplug hole 120. In this example embodiment, the sparkplug 121 and sparkplug hole 120 are threaded, thus allowing the sparkplug 121 to screw into the sparkplug hole 120.
Generally, an internal combustion engine is well sealed such that the expanding gases from the combustive process can be efficiently converted into rotational motion. In a traditional piston-based internal combustion engine, a piston moves up and down within a cylinder. The cavity formed by the piston and cylinder is the combustion chamber in which a fuel is combusted. In order for the expanding gases from the combustion to efficiently move the piston within the cylinder, the piston forms a seal against the wall of the cylinder. In typical automotive designs, piston rings are used to seal the piston against the cylinder.
In some embodiments, a sealing structure 515, shown in
In the depicted embodiment of the rotary wing engine 105, the engine housing 110, end plates 115, rotor 135, and wing assemblies 145 create a plurality of first sealed chambers 150. Each wing assembly 145 and a corresponding arm 410 isolate the first chambers 150 in conjunction with the inner surface 111 of the engine housing 110. Each wing assembly 145 and the rotor 135 also isolate a second chamber 155. Therefore, the rotor 135 and wing assemblies 145 may include seals that provide a seal against the engine housing 110 and end plates 115. The rotor 135 and wing assemblies 145 may also include seals that provide a seal against each other. The sealing mechanisms of the rotor 135 and wing assemblies 145 are described in detail below with reference to
The sealing edges 411 of the rotor 135 lie along the outside diameter of the rotor 135 and are positioned to be very close but not in contact with the inner surface 111 of the engine housing 110. The engine housing 110, end plates 115, rotor 135, and wing assemblies 145 form a plurality of first sealed chambers 150. The end plates 115, rotor 135, and wing assemblies 145 also form a plurality of second sealed chambers 155. Though the depicted embodiment of the rotary wing engine 105 includes a total of four wing assemblies 145, other embodiments may use more or fewer wing assemblies 145. Although the embodiment of
The sparkplug hole 120 allows the sparkplug 121 to extend inside the rotary wing engine 105 to initiate a combustion, further described in detail below with reference to
In some embodiments, a groove 440 may be formed in each arm 410. This groove may serve to allow air to flow between one second sealed chamber 155 to another second sealed chamber 155 as the second sealed chambers 155 increase or decrease in volume. In other embodiments, a hole may be formed in each arm 410 to allow air to flow between one second sealed chamber 155 to another second sealed chamber 155. In some embodiments, a pivot hole 425 may be formed in the hinge protrusion 415. In some embodiments, a seal groove 420 may be formed in each arm 410. A sealing structure 515 rests in the seal groove 420, further described below in detail with reference to
The outer surface 506 may extend from the leading edge 540 to the trailing edge section 545 and may have a radius of curvature that is the same as the internal surface 111 of the engine housing 110. The outer surface 506 having the same radius of curvature as the internal surface 111 advantageously allows the wing 505 to more thoroughly compress the combustible gas during the compression step of the rotary wing engine 105, further described in detail below with reference to
The leading edge 540 may face a corresponding arm 410 of the rotor 135. A corresponding arm 410 of a wing herein refers to an arm of the rotor 135 that abuts the leading edge of the wing.
A seal groove 510 may be formed in the wing 505 to allow the sealing structure 515 to be secured to the wing 505, as described below in detail with reference to
In some embodiments, the cam track 116 constrains the rotation of the wing assemblies 145 with reference to the rotor 135 by guiding the leading pin rollers 535 along a path determined by the cam track 116 as the rotor 135 rotates within the engine housing 110.
In some embodiments, the cam track 116 is isolated from the first sealed chamber 150 during the ignition of the combustible gas during the operation of the rotary wing engine 105. In other words, the first sealed chamber 150 does not communicate with the cam track 116 during the power step of the operation of the rotary wing engine 105, further described below with reference to
In some embodiments, the various components of the wing assembly 145 may be made of an aluminum alloy. In other embodiments, the various components of the wing assembly 145 may be made of steel or various other metallic and non-metallic materials.
In some embodiments, the trailing edge section 545 has a radius of curvature 625 that corresponds to the distance between the axis of the hinge pin 520 and the inner surface 111 of the engine housing 110. This allows the trailing edge section 545 of the wing 505 to remain in contact with the inner surface 111 of the engine housing 110 as the wing 505 rotates about the axis of the hinge pin 520 relative to the rotor 135. A seal groove 510, a hole 521, and a hole 531 may be formed in the wing 505. Trailing edge section seal grooves 511 may be formed in the wing 505 on the trailing edge section 545. The trailing edge section seal grooves 511 allow additional the trailing edge sealing structures 516 to be mounted to the wing 505 to seal the trailing edge section 545 of the wing 505 against the inner surface 111 of the engine housing 110. The trailing edge sealing structures 516 advantageously accommodate minor variations in the distance between the trailing edge section 545 and the inner surface 111 of the engine housing 110. The distance between the axis of the leading pin 530 and the axis of rotation 615 of the rotor 135 is represented by line 605. The distance between the axis of the hinge pin 520 and the axis of rotation 615 of the rotor 135 is represented by line 610. In some embodiments, the line 605 may be different from the line 610.
The first member 705 may further include, among other structures, three sub-members 715, 720, and 721. The three sub-members 715,720 and 721 are parallel and extend across the first length 706. Sub-member 715 and sub-member 720 are connected by bridge 725, and sub-member 720 and sub-member 721 are connected by bridge 722. The three sub-members 715, 720, and 721, in conjunction with bridges 722 and 725, form a double cantilever structure that provides resilience in the direction of the first width 707 of the first member 705, as indicated by the arrow 730. The second member 710 may further include, among other structures, three sub-members 735,740, and 741. The three sub-members 735,740 and 741 are parallel and extend across the second length 711. Sub-member 735 and sub-member 740 are connected by a bridge 745, and sub-member 725 and sub-member 741 are connected by a bridge 746. The three sub-members 735,740, and 741, in conjunction with bridges 745 and 746, form a double cantilever structure that provides resilience in the direction of the second width 712 of the second member 710, as indicated by the arrow 750. The third member 755 may further include, among other structures, three sub-members 760, 765, and 770. The three sub-members 760, 765, and 770 are parallel and extend across the third length 756. Sub-member 760 and sub-member 765 are connected by a bridge 775, and sub-member 760 and sub-member 770 are connected by a bridge 780. The three sub-members 760, 765, and 770, form a double cantilever structure that provides resilience in the direction of the third width 757, as indicated by arrow 785. In some embodiments, the second member 710 is curved in a direction perpendicular to the width of the second member 710. In some embodiments, the third member 755 is curved in a direction perpendicular to the width of the third member 755. In an alternative embodiment, the seal structure 515 may only include the first member 705 and the second member 710.
In some embodiments, the sealing structure 515 may be inserted into the seal groove 510 of the wing 505 so that the seal groove 515 receives sub-member 721 of the first member 705, sub-member 741 of the second member 710, and sub-member 770 of the third member 755. The sub-member 721 rests in the section of the seal groove 510 in the leading edge 540 of the wing 505. The second member 710 and third member 755 extend from the leading edge 540 to the trailing edge section 545, parallel to the outer surface 506, sub-members 741 and 770 resting in the sections of the seal groove 510 on either side of the wing 505. When the wing assembly 545 is connected to an arm 410 of the rotor 135, the first member 705 of the sealing structure 515 abuts the curved surface 430 of the corresponding arm 410 that the leading edge 540 faces, as described above in reference to
In some embodiments, a sealing structure including only the first member 705 of the sealing structure 515 may be inserted into the trailing edge section seal grooves 511 on the wing 505. This seals the trailing edge section of the wing 505 against the inner surface 111 of the engine housing 110 as the wing 505 rotates with reference to the rotor 135.
In some embodiments, the sealing structure 515 may also be inserted into the seal groove 420 on the arm 410 of the rotor 135. The first member 705 rests in the section of the seal groove 420 on the sealing edge 411 of the arm 410. The second member 710 and third member 755 extend from the sealing edge 411 towards the center of the rotor 135, parallel to the curved surface 430, resting in the sections of the seal groove 420 on either side of the arm 410. The first member 705 seals the sealing edge 411 against the inner surface 111 of the engine housing 110. The second member 710 and the third member 755 advantageously seal the arm 410 of the rotor 135 against each end plate 115. The resilience of the members of the sealing structure 515 accommodates minor variations in the distances between corresponding components. In other embodiments, a sealing structure similar to the sealing structure 515 may be inserted into the seal groove 420 of the rotor 135.
Referring back to
The operation of the rotary wing engine 105 will be described below with reference to
Once the exhaust step of the operation of the rotary wing engine 105 is completed, the wing assembly 805 is positioned to begin the intake step of the rotary wing engine 105, and the rotor 135 continues to rotate counterclockwise. In reference to
The four steps of operation described with reference to wing assembly 805 apply to each of the wing assemblies 145, offset by one step. For example, as a first wing assembly undergoes the intake step depicted in
The design of the rotary wing engine 105 is inherently balanced. As depicted in
In some embodiments, a hole may be formed in each arm 410 of the rotor 135 extending from each second sealed chamber 155 to the adjacent second sealed chamber. These holes may allow air to flow freely between the plurality of second sealed chambers 155. In some embodiments, this air flow may decrease the force opposing the motion of each wing assembly 145. For example, as the wing assembly 805 and the opposing wing assembly rotate clockwise, the volume of the corresponding second sealed chambers increases. Simultaneously, the remaining two wings assemblies rotate counterclockwise, decreasing the volume of their corresponding second sealed chambers 150. The holes in the rotor 135 may allow air to flow from the decreasing second sealed chambers to the increasing second sealed chambers.
As is described with reference to
Various components of the rotary wing engine 105 may be manufactured through an extrusion process. The uniform cross-sections of various components make the components particularly well-suited for manufacturing by extrusion. For example, the engine housing 110, the rotor 135, and wings 505 may be manufactured using an extrusion process. The details of the extrusion manufacturing process are well known in the related field and will not be described further.
In other embodiments, various components of the rotary wing engine 105 are manufactured through a combination of extrusion and traditional machining For example, the cylindrical form of the engine housing 110 may be extruded, and then the tubes 205 may be formed by machining.
Thus, while particular embodiments and applications have been illustrated and described, it is to be understood that the disclosed embodiments are not limited to the precise construction and components disclosed herein. Various modifications, changes and variations, may be made in the arrangement, operation and details of the method and apparatus disclosed herein without departing from the spirit and scope defined in the appended claims.
This application claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/785,859 filed Mar. 14 2013, which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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61785859 | Mar 2013 | US |