1. Technical Field
Internal combustion engines having rotating cylinder assemblies.
2. Description of Related Art
Despite the ongoing advances made in energy conversion devices, the piston-based internal combustion (IC) engine remains in widespread use as a power plant for automobiles and industrial applications. It appears that the IC engine will continue to have widespread use well into the future, particularly because there remains considerable opportunity to improve its energy conversion efficiency, as well as other operational aspects.
The vast majority of IC engines currently in use have an “in-line” configuration of cylinders. Such an IC engine may have a single block of cylinders having pistons operatively connected to a crankshaft by rods, or an IC engine may have a pair of blocks of cylinders formed in a V configuration in an engine block, each of the cylinders having pistons operatively connected to a single crankshaft by rods. “V8” engines, as well as “V-twins” (two cylinder), V4s, V6s, V10s, and V12s have this configuration, and are in use today.
In an alternative configuration, an IC engine may have a rotary configuration in which a block of cylinders is connected to a central crankshaft by rods. In operation of a rotary IC engine, the entire block of cylinders rotates. The pistons of the cylinder block are connected to the crankshaft by rods, and undergo reciprocating motion during a combustion cycle, thereby causing rotation of the crankshaft and the block of cylinders.
The rotary piston engine had substantial use in early IC engine driven aircraft, but was eventually rendered obsolete by advances in alternative power plants, including turbine-based propulsion. Rotary piston engines of that era had high fuel consumption and high oil consumption. Additionally, air drag from the rotating cylinder assembly increases with the square of rotational speed, which limited the maximum RPM at which these engines could operate, thus limiting maximum power output.
Rotary engines, much like conventional in-line fixed block engines, also have undesired complexity in the components required to provide the intake of combustible air/fuel mixture, and the supply and timing of ignition energy. Most rotary engines are configured to operate with multiple spark ignition sources disposed around the rotating cylinder assembly. The timing of these ignition sources in the combustion cycles of the cylinders must be managed, adding further complexity. Additionally, many rotary engine configurations are limited to operating as two-cycle engines due to their intake and exhaust designs.
However, despite these problems, the rotary piston IC engine has certain inherent advantages over the in-line stationary cylinder block engines in single and V-configurations. Because of the lack of a heavy crankshaft as used in in-line fixed block engines, rotary piston engines run with less vibration. They also have a high power-to-weight ratio. Additionally, the rotary piston assembly itself acts as a flywheel; thus there is no need to add the rotating mass of a solid plate flywheel, as is done in conventional in-line fixed block engines. If at least some of the problems could be solved by a rotary IC engine having an improved design, the rotary IC engine could become a valuable alternative power plant for automobiles and industrial applications, acting as a bridge to alternative energy conversion and transportation devices that will not be commercialized until well out in the future.
In accordance with the present disclosure, there is provided an internal combustion engine comprising an engine block comprised of a main cavity, an intake plenum, and an exhaust plenum; a crankshaft supported within the main cavity of the engine block; a rotating piston assembly contained within the main cavity of the engine block and comprised of a rotatable cylinder housing having a housing axis of rotation and comprised of a plurality of pistons contained in combustion cylinders; and a rotating valve ring contained within the engine block and surrounding the rotating piston assembly, and comprised of valve port sets comprising intake ports, ignition energy ports, and exhaust ports communicable with each of the plurality of combustion cylinders. The rotatable cylinder housing has an axis of rotation that is parallel to and offset from the crankshaft axis of rotation.
Each of the plurality of combustion cylinders is comprised of a cylindrical side wall and a top wall formed in the cylinder housing. Each piston is contained in a combustion cylinder is operatively connected by a piston rod to the crankshaft and reciprocable along the central axis of the respective cylindrical side wall. For each of the plurality of pistons in combustion cylinders, the piston and the cylindrical side wall and top wall of the cylinder form a variable volume combustion chamber.
By virtue of the offset of the cylinder housing axis of rotation from the crankshaft axis of rotation, in operation of the engine, rotation of the piston assembly around its axis of rotation causes the distance from the crankshaft to the cylindrical wall of each combustion cylinder to vary periodically, thereby causing each piston to reciprocate within its cylindrical wall in repeated intake, compression, power, and exhaust strokes. Additionally, the rotating piston assembly and the rotating valve ring are operatively coupled to the crankshaft such that during operation of the engine, the rotating piston assembly and the rotating valve ring rotate synchronously with rotation of the crankshaft.
Thus during operation of the engine through a combustion cycle of intake, compression, power, and exhaust strokes of the pistons, for each respective combustion cylinder, the following occurs:
These and other aspects of the IC engine of the present disclosure are provided subsequently herein.
The present disclosure will be provided with reference to the following drawings, in which like numerals refer to like elements, and in which:
The present invention will be described in connection with certain preferred embodiments. However, it is to be understood that there is no intent to limit the invention to the embodiments described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
For a general understanding of the present invention, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to designate identical elements. In the following disclosure, certain components may be identified with adjectives such as “front”, “rear,” “top,” “upper,” “bottom,” “lower,” “left,” “right,” etc. These adjectives are provided in the context of the orientation of the drawings, which is arbitrary. The description is not to be construed as limiting the engine to use in a particular spatial orientation. The instant engine may be used in orientations other than those shown and described herein. Additionally, certain components of the engine as depicted in the drawings may be larger or smaller relative to other components; the drawings are not to be considered as drawn to scale.
Additionally, a “gas” as used herein when referring to a compressible fluid being taken into a combustion chamber during an intake cycle of the engine is meant to indicate a compressible fluid that may only have gaseous molecules, but that may also include fine droplets of liquid phase molecules (typically liquid fuel molecules) in droplet forms such as mists and aerosols.
Referring first to
The engine block 20 is further comprised of a main cavity 22 that contains the rotating piston assembly 100 and a rotating valve ring 300. The engine block 20 may also include an intake plenum 24 that is configured to receive a combustible gas from a fuel source (not shown) and direct the combustible gas through the valve ring 300 and into the respective combustion cylinders 1, 2, 3, 4, and 5, where combustion occurs during the respective power strokes of the combustion cylinders 1-5. In an alternative embodiment (not shown), the intake plenum 24 may be provided as a separate intake manifold piece that is joined to the engine block 20. The fuel source (not shown) may be carburetor or a fuel injector that is supplied with a gaseous combustible fuel or a liquid combustible fuel that is atomized and evaporates before or during combustion in the combustion cylinders. The fuel injector may be located in a manifold (not shown) that is joined to the intake plenum, or the fuel injector may be mounted in a port (not shown) that extends through the external wall 21 of the engine block 20 into the plenum 24.
The engine block 20 may also include an exhaust plenum 26 that is configured to receive a combustion exhaust gas from the respective combustion cylinders 1, 2, 3, 4, and 5 through the valve ring 300 and direct the exhaust gas out of the engine block 20 into the ambient atmosphere, or into an emissions abatement device (not show), such as a catalytic convertor. In an alternative embodiment (not shown), the exhaust plenum 26 may be provided as a separate exhaust header piece that is joined to the engine block 20.
The engine block may be further comprised of an ignition source port 28 for directing ignition energy into the combustion cylinders 1-5 during operation of the engine 10. The ignition source port 28 may be formed in a boss 27 that extends outwardly from the external wall 21 of the engine block 20. The ignition source port 28 may be provided with threads (not shown) for engagement with corresponding threads of a spark plug (not shown), which may be used to provide the ignition energy.
The engine 10 is further comprised of a crankshaft 50 that is driven by the action of the pistons during their respective power strokes as will be described subsequently herein. The crankshaft 50 is supported within the main cavity 22 of the engine block. In the embodiment of the engine 10 depicted in
Referring in particular to
Each of the plurality of combustion cylinders 1-5 is comprised of a cylindrical side wall and a top wall formed in the cylinder housing 110. The pistons 101-105 contained in respective combustion cylinders 1-5 are operatively connected by respective piston rods 111, 112, 113, 114, and 115 to a radial flange 52 of the crankshaft 50. The connections of the piston rods 111-115 to the radial flange 52 are offset from the axis of rotation 51 of the crankshaft 50 so that during the respective power strokes of the pistons 101-105, torque is applied to the crankshaft 50, thereby resulting in crankshaft rotation as indicated by arrow 59. The pistons 101-105 are reciprocable along the central axes of their respective cylindrical side walls 121, 122, 123, 124, and 125. For each of the plurality of pistons 101-105 in combustion cylinders 1-5, the piston and the cylindrical side wall and top wall of the cylinder form a variable volume combustion chamber.
Referring again to
By virtue of the offset of the cylinder housing axis of rotation 109 from the crankshaft axis of rotation 51, in operation of the engine 10, rotation of the piston assembly 100 around its axis of rotation 109 causes the distance from the crankshaft 50 to the respective cylindrical walls 121-125 of each of the combustion cylinders 1-5 to vary periodically, thereby causing each piston 101-105 to reciprocate within its cylindrical wall in repeated intake, compression, power, and exhaust strokes. Additionally, the rotating piston assembly 100 and the rotating valve ring 300 are operatively coupled to the crankshaft 50 by gearing such that during operation of the engine 10, the rotating piston assembly 100 and the rotating valve ring 300 rotate synchronously with rotation of the crankshaft 50.
These principles will now be explained in detail with reference to
The operation of the front gear set 30 will now be described with reference in particular to
Shaft gear 32 is fixed to crankshaft 50, and is directly driven by crankshaft 50, by virtue of engagement of drive star 55 of crankshaft 50 with drive star cutout 34 in shaft gear 32. Thus the drive star 55 serves as a means of direct connection between the shaft gear 32 and the crankshaft 50. Valve ring annular gear 36 is joined to rotating valve ring 300 by suitable fasteners 37; thus when valve ring annular gear 36 is driven rotationally, rotating valve ring 300 also rotates. In like manner, piston annular gear 38 is joined to rotating piston assembly 100 by suitable fasteners 39; thus when piston annular gear 38 is driven rotationally, rotating piston assembly 100 also rotates.
The operation of the gear set 30 during the operation of engine 10 will now be described. It is to be understood that the operation of gear set 30 is meant to be exemplary and not limiting. The various gear sets may have different ratios and configurations, depending upon the number of cylinders in the engine 10, and the number of valve port sets in the rotating valve ring 300.
Referring to
Double annular gear 40 is also comprised of an inner gear 44 that is engaged with a front gear 47 of main gear set 46, which rides rotationally on the central region 56 of crankshaft 50. Inner gear 44 has 36 teeth, and front gear 47 has 16 teeth. Thus the single rotation of crankshaft 50 that results in a 2/3 rotation of double annular gear 40 also causes 2/3×36/16 rotations, i.e. 1½ rotations of front gear 47, as well as middle gear 48 and rear gear 49 of main gear set 46.
It is noted that the position of double annular gear 40 may be fixed by its engagement with shaft gear 32 and main gear 46, and in the axial direction by shaft gear 32 and valve ring annular gear 36. Alternatively, double annular gear may be supported by a bearing (not shown) that is provided in engine block 20 or cover 23.
Rear gear 49 of main gear set 46 is engaged with piston annular gear 38. Rear gear 49 has 16 teeth, and piston annular gear 38 has 24 teeth. Thus the single rotation of crankshaft 50 that results in 1½ rotations of rear gear 49 also results in 1.5×16/24 rotations, i.e., one rotation of piston annular gear 38, as well as rotating piston assembly 100. Thus crankshaft 50 and rotating piston assembly 100 rotate in unison, but on rotational axes that are offset from each other by virtue of the arrangement of the gears.
Middle gear 48 is engaged with valve ring annular gear 36. Middle gear 48 has 15 teeth, and valve ring annular gear 36 has 24 teeth. Thus the single rotation of crankshaft 50 that results in 1½ rotations of middle gear 48 also results in 1.5×15/24 rotations, i.e., 15/16 rotation of valve ring annular gear 36, as well as rotating valve ring 300.
Because the engine 10 operates as a four cycle engine, two rotations of the rotating piston assembly 100 and the crankshaft 50 occur for each combustion cycle, while the rotating valve ring 300 rotates 1⅞ times. The rotational ratio of the rotating cylinder assembly 100 to the rotating valve ring 300 is thus 16/8: 15/8, or 16:15. This difference between the rotational rates of the rotating cylinder assembly 100 to the rotating valve ring 300 provides the desired intake valve, ignition, and exhaust valve timing during the combustion cycle, as will be explained subsequently herein.
The operation of the rotating piston assembly 100 in combination with the rotating valve ring 300 to accomplish the combustion cycle for each respective combustion cylinder of intake, compression, power, and exhaust will now be described with reference to
Combustion cylinder 1 is further comprised of a port 141 that extends through the rotatable cylinder housing 110 from the top wall 131 of cylinder 1 to the external surface 117 of cylinder housing 110. In the operation of engine 10, the port 141 functions as a conduit for conveying fuel and air into combustion cylinder 1 during the intake stroke of the combustion cycle, and as a conduit for conveying ignition energy into combustion cylinder 1 during the ignition step of the combustion cycle, and as a conduit for conveying hot exhaust gases from combustion cylinder 1 during the exhaust stroke of the combustion cycle. Thus a single port is used for all three functions, in contrast to the dedicated spark plug, intake and exhaust valve ports provided in the cylinder heads of conventional internal combustion engines. In like manner, combustion cylinders 2-5 are further comprised of respective ports 142, 143, 144, and 145 that extend through the rotatable cylinder housing 110 from the respective top walls 132, 133, 134, and 135 to the external surface 117 of cylinder housing 110.
This use of a single port for these three functions is made possible by the configuration and operation of the rotating valve ring 300, and its synchronous rotation with the rotating cylinder assembly 100. Referring again to
During the combustion cycle, the rotating valve ring rotates synchronously with the rotating cylinder assembly 100, but at a different rotational rate via the gearing described previously, so as to align an intake port with a combustion cylinder during the intake stroke, and to align an ignition port at the required time of ignition, and to align an exhaust port with a combustion cylinder during the exhaust stroke. This alignment of ports, which enables the combustion cycle for each cylinder of the engine 10 will now be described for combustion cylinder 1 only with reference to
Summary of Intake Stroke:
During the intake stroke of a piston from a distal end of a cylinder to the proximal end of the cylinder, the rotating valve ring positions an intake port for the respective combustion cylinder so that the combustion chamber of the cylinder is in communication with the intake plenum, thereby causing a gas contained in the intake plenum to flow into the combustion chamber. The intake stroke for cylinder 1 is depicted in
Turning first to
Referring to
Referring to
Summary of Compression Stroke:
During the compression stroke of the piston from the proximal end of the cylinder to the distal end of the cylinder, the rotating valve ring positions a first barrier wall that seals the top wall of the combustion cylinder, thereby causing compression of the gas in the combustion chamber as the piston moves from the proximal end of the cylinder to the distal end of the cylinder. The compression stroke for cylinder 1 is depicted in
Turning first to
Referring to
Summary of Ignition:
At or near the end of the compression stroke of the piston, the rotating valve ring positions an ignition energy port in communication with the combustion chamber and an ignition energy source, thereby delivering ignition energy to the gas and igniting the gas. The ignition step for cylinder 1 is depicted in
Referring to
In certain embodiments, the ignition energy source may be a spark plug (not shown) that is fitted in ignition source port 28. Energizing of the spark plug is controlled such that the sparking of the plug is timed to occur at the time that ignition energy port 321 is aligned with cylinder port 141. The sparking element of the spark plug may extend down within ignition energy port 321 to the point where it is nearly in contact with surface 117 of cylinder housing 110. The sparking element may be configured to fire a high energy electrical discharge down through cylinder port 141 into cylinder 1.
It is noted that in the embodiment of the engine 10 depicted in
It is also noted that in the previous description of the intake stroke, compression stroke, and ignition step, these operations have been described in the context of there being an external source of combustible gas or combustible liquid fuel droplets, which is delivered through the intake plenum 24 of the engine block 20. However, it is not necessary that the combustible fuel be provided from an external source and delivered to plenum 24. In an alternative embodiment (not shown), a fuel injector (or multiple injectors) may be provided for delivery of combustible fuel. This injector may be fitted to the engine block in a region where it is in communication with the plenum 24, so that it injects combustible gas or atomized liquid directly into plenum 24 during the intake stroke of any cylinder 1-5. The fuel injector(s) may be oriented so that the injection spray or gas discharge is directed at the intake port of the rotating valve ring 300 as it rotates past the injector(s).
It is also noted that in the above descriptions of the intake stroke, compression stroke, and ignition step, these operations have been described in the context of the combustible mixture being formed in advance of being taken into a combustion cylinder, i.e. the combustible mixture is formed in a manner similar to a conventional spark ignition gasoline or compressed natural gas (CNG) engine.
However, it is not necessary that the combustible mixture be formed in advance of ignition thereof. In an alternative embodiment (not shown), the engine 10 may be operated as a diesel engine. In such an embodiment, a diesel fuel injector may be provided for injection of diesel fuel into the cylinders 1-5 at the desired ignition time. In certain embodiments, the diesel fuel injector may be fitted to the ignition source port 28 of the engine block 20, so that it injects diesel fuel directly into a cylinder, such as into cylinder 1 through ignition energy port 321 and cylinder port 141. The fuel then ignites as in a conventional diesel engine. In that regard, the ignition energy source that causes ignition of the combustible gas in the cylinder is the diesel fuel itself.
With the ignition of the combustible gas in the cylinder having occurred, the power stroke of engine 10 now proceeds.
Summary of Power Stroke:
During the power stroke of the piston from a distal end of the cylinder to the proximal end of the cylinder, the combustible gas burns while the rotating valve ring positions a second barrier wall that seals the top wall of the combustion cylinder, thereby causing an increase in pressure within the combustion chamber, thereby applying a force on the piston and the connecting rod in the proximal direction, and thereby applying a torque on the crankshaft to cause crankshaft rotation. The power stroke for cylinder 1 is depicted in
Turning first to
It is noted that the location of the connections of the rods 111-115 to the crankshaft 50 may be different than what is depicted in the drawings. For example, each of the rods 111-115 may be connected to the flange 52 of the crankshaft at a location that is further around the crankshaft in the clockwise direction in
Additionally, the Applicant has performed a vector analysis of forces that occur during operation of the internal combustion engine 10. Without wishing to be bound to any particular theory, the Applicant believes that during operation of the engine 10, the reciprocating action of the pistons 101-105 within their respective cylinders provides an additional torque on the rotating cylinder assembly 100, which in turn is applied to the crankshaft 50.
Referring to
Summary of Exhaust Stroke:
During the exhaust stroke of the piston from the proximal end of the cylinder to the distal end of the cylinder, the rotating valve ring positions an exhaust port for the respective combustion cylinder so that the combustion chamber of the cylinder is in communication with the exhaust plenum, thereby causing combustion gas contained in the combustion chamber to flow into the exhaust plenum and out of the engine. The exhaust stroke for cylinder 1 is depicted in
Turning first to
Referring to
Referring to
With a small further angular displacement of the rotating cylinder assembly 100 and rotating valve ring 300, the piston 101 ceases its upward motion at top dead center, and is in the position as shown in
In the embodiment of the engine 10 depicted in
It is to be understood that other configurations of the engine 10 are contemplated. Firstly, the engine 10 may be comprised of more or less than five cylinders 1-5. Secondly, other port configurations for the rotating valve ring 300 are possible. The rotating valve ring 300 may have more or fewer port sets, so long as the proper gearing is provided so as to align an intake port with a cylinder port during the intake stroke, and to align an ignition port with the cylinder port during delivery of ignition energy, and to align an exhaust port with the cylinder port during the exhaust stroke. The gearing between the rotating cylinder assembly 100 and the rotating valve ring 300 as described previously herein is thus adjusted accordingly to provide the required rotational ratio to accomplish the desired alignment of the ports during intake, ignition, and exhaust.
Additionally, it is not required that the rotating cylinder assembly 100 rotates at a higher speed than the rotating valve ring 300. In other embodiments, the rotating cylinder assembly 100 may rotate at a lower speed than the rotating valve ring 300. In such a configuration, the order of porting of the rotating valve ring simply needs to be reversed, i.e., the porting order is exhaust-ignition-intake, rather than intake-ignition-exhaust as shown in
The respective materials of construction of the engine block 20, the cylinder housing 110, the pistons 101-105, the piston rods 111-115, the crankshaft 50, and the rotating valve ring 300 may be the same as used for analogous parts in conventional internal combustion engines. Such materials may include but are not limited to cast iron, aluminum alloys, steel alloys, and ceramics, with the operative requirements for any particular material including sufficient structural strength, resistance to heat generated by combustion of fuel within the cylinders, and resistance to chemical degradation by the fuel and by the hot exhaust gases.
In certain embodiments, the number of sets of valve port sets S may be defined by the relationship:
S=(1.5×C)+0.5
where C is equal to any odd number of combustion cylinders.
Additionally, the ratio R of the number of rotations of the rotating cylinder assembly 100 to the number of rotations of the rotating valve ring 300 may be defined by the relationship:
R=1+1/(3C).
It can be seen that for the exemplary internal combustion engine depicted in the drawings and described herein, the above equations apply. The exemplary engine has five cylinders. Thus S=16/15, and R=8 port sets as described previously.
The rotating cylinder assembly 100 and rotating valve ring 300 may be provided with seals to contain the combustible intake mixture and the combustion gases within the desired locations of the engine 10 during the combustion cycle. Referring again to
The various seals are made of materials such as, e.g., a fluoropolymer or a ceramic, that are suitably resistant to heat and chemical degradation by the combustion fuel and the hot exhaust gases.
It is, therefore, apparent that there has been provided, in accordance with the present invention, an internal combustion engine. Having thus described the basic concept of the invention, it will be rather apparent to those skilled in the art that the foregoing detailed disclosure is intended to be presented by way of example only, and is not limiting. Various alterations, improvements, and modifications will occur to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested hereby, and are within the spirit and scope of the invention. Additionally, the recited order of processing elements or sequences, or the use of numbers, letters, or other designations therefore, is not intended to limit the claimed processes to any order except as may be specified in the claims.