Patent Application
20180347363
This invention relates to rotary machines and more particularly to rotary machines which can be constructed for operation as internal combustion engines, fluid pumps, air/gas expanders, and air/gas compressors. The present application is a continuation-in-part of my prior U.S. Pat. No. 7,896,630 filed Feb. 13, 2007 and awarded Mar. 1, 2011, which has expired.
Not Applicable
Not Applicable
The present invention relates to a rotary device and, in particular, to sealing reciprocating vanes of a rotary device.
Rotary devices have long been thought to be an efficient way of rotating a shaft in the case of a rotary engine, pumping a fluid in the case of a pump, and compressing a fluid in the case of a compressor. Rotary devices are generally characterized by a rotating “piston”, or the equivalent, instead of a traditional linearly reciprocating piston as found in piston engines, pumps, and compressors. However, sealing the rotating “piston” has presented an extremely challenging problem, ultimately resulting in lack of widespread adoption of this technology. The sealing problems are particularly acute in a rotary engine as compared to a pump or a compressor. This is mainly because a combustion engine typically operates at higher pressures and temperatures, and therefore requires tighter sealing than in other applications. An inherent conflict in this technology is that tighter sealing may result in excessive friction and premature seal failure.
Many different approaches have been tried to address sealing issues with rotary devices including the elimination of seals altogether and reliance instead on close tolerances and accurate machining to seal leakage. Although in principle this approach can work for lower pressure and temperature applications, it is unsuitable for the higher temperatures and pressures of rotary engines where friction and thermal expansion are present. Ultimately the rotating “piston” will get hotter than the external casing. A “piston” that is a snug fit when the rotary engine has just been started will become tighter and tighter as it heats. A further complication is that unequal heating of the various parts will lead to non-uniform expansion of the parts, resulting in changes in shape as well as in size that make sealing attempts through tolerances and accurate machining unsuccessful in rotary engines.
Rotary engines have long been thought to be a viable replacement for the standard reciprocating piston engines. Rotary engines offer possible increases in mechanical and fuel efficiency, as well as more compact dimensions and a lower weight. The major deficiencies in traditional reciprocating piston engines arise from the short stroke of the pistons which leads to incomplete combustion. In theory, rotary engines provide a more continuous power stroke with decreased structural complexity, due mostly to the reduction in the number of moving parts. In practice, however, rotary engines have not received widespread acceptance and have only had limited success in replacing reciprocating piston engines, due mainly to the complexities involved in building a “simpler” rotary engine. Specifically, rotary engines typically involve a complex-shaped combustion chamber which presents problems in sealing the combustion chamber. The inability to adequately seal the combustion chamber has lead to many failed prototypes of the rotary engine.
One rotary engine that has received some commercial acceptance is the Wankel engine, original U.S. Pat. No. 2,988,065, which has been used in some models of automobiles produced by Mazda. A Wankel engine has a triangular shaped rotor, i.e., a rotating “piston” incorporating a central ring gear which is driven around a fixed pinion within an oval shaped housing. The triangular shaped rotor creates three combustion chambers between the rotor and the interior walls of the housing as the rotor turns within the housing. Each of the three rotating combustion chambers dynamically changes in volume as the triangular rotor rotates in the oblong housing and undergoes the four stages of the Otto cycle—intake, compression, ignition and exhaustion. The rotary motion is transferred to the drive shaft via an eccentric wheel that rides in a bearing in the rotor that matches the central ring gear. The drive shaft rotates once during every power stroke instead of twice as in a typical four stroke reciprocating piston engine. The Wankel engine promised higher power output with fewer moving parts than the Otto cycle reciprocating piston engine, however, technical difficulties associated with sealing the three rotating combustion chambers have apparently interfered with widespread adoption.
Another type of rotary engine is known as the axial vane rotary engine. In an axial vane rotary engine, a circular rotor is located between two cams, each cam having a cooperating undulating cam surface facing the rotor. The rotor has a series of angularly spaced slots to receive axially sliding vanes whose ends form reciprocating contact with each of the opposing undulating cams surfaces so that combustion chambers are dynamically formed between adjacent axially sliding vanes. Axial vane rotary engines are described in U.S. Pat. Nos. 4,401,070, 5,429,084, 5,509,793 5,551,853, and 7,896,630; all of which are herein incorporated by reference.
An axial vane rotary engine has the capacity to provide greater output than a Wankel rotary engine of the same size. However, an axial vane rotary engine presents a greater sealing challenge since the vanes slide both axially with respect to the rotor and circumferentially with respect to the cam surfaces. The present invention is directed to a rotary device of improved design over the prior art which facilitates the ability to adequately seal the combustion chambers formed between adjacent vanes.
The Circle-Ellipse Engine leverages the outstanding work accomplished by Mazda in sealing the combustion chamber of its Wankel engine design. Further, it greatly simplifies the contributions by Cherry in promulgating the pioneer work by McCann in the opposing cam axial-vane rotary engine.
This device eliminates the complex and expensive machining associated with the epitrochoid housing and triangular central rotor of the Mazda-Wankel implementation.
Instead, this device integrates a geometrically standard ellipse as the cam surface, and integrates a circular rotor facing the cam surface. The innovation is the pin track in the end plates. This track serves to accurately position the tip of the vane a fixed distance from the cam surface for all angles of rotation of the rotor. Now managed with constant distance, the small gap is effectively sealed by an Apex Seal identical to that of the Mazda-Wankel implementation.
Prior attempts at implementing a pin track failed. They were based on following the geometry of the cam. This was a mistake, and resulted in a varying solution of the distance from the vane tip to the cam surface.
The correct implementation in this innovation is a pin track derived from the three contributing elements; namely the cam surface (an ellipse), the rotor (a circle), and the host end plates (fixed location). The solution is a complex transcendental equation that properly integrates the geometry of the three independent components.
It is understood that one of skill in the art of rotary devices can apply the principles discussed herein in the various embodiments equally to other rotary devices such as pumps, compressors, expanders, etc.
The invention will be more readily understood from the following description of preferred embodiments thereof given, by way of example only, with reference to the accompanying drawings, in which:
A Circle-Ellipse Engine comprises a stationary circular outer Housing having a fixed elliptical inner cam surface, and a separate internal round Rotor partitioned into equal segments that are populated by identical movable radial Vanes. During rotation, the end of the Vanes are positioned a constant distance from the elliptical inner cam surface of the Housing. The internal round Rotor has the same radius as the minor axis of the elliptical inner cam surface. During rotation, a variable height cavity is created representing the difference between the major and minor axes of the elliptical inner cam surface and the Rotor face.
The position of the radial Vanes is guided by the slots in the symmetrical Rotor, extending to the elliptical inner cam surface of the Housing. The precise extension is governed by a pin track machined into the dual End Plates.
There are no pistons, camshaft, timing chains, valves, valve lifters, rocker arms, connecting rods, or wrist pins. As a benefit, size and weight are significantly reduced when compared to a reciprocating engine of similar horsepower. Normal aspirated air is continuously drawn into the engine when an adjacent pair of radial Vanes passes the air inlet port. Similarly, exhaust products are expelled after a combustion event when the pair of adjacent Vanes passes over the exhaust port.
The resultant geometer results in a continuous implementation of the Otto Cycle; namely intake, compression, expansion or power stroke, and exhaust during a single rotation of the internal round Rotor.
Because the Otto Cycle is executed each revolution of the Rotor, the Circle-Ellipse Engine achieves the same power as a conventional reciprocating engine of the same displacement and compression ratio, at half the RPM. This implementation greatly reduces component ware and extends the life and maintenance cycle by a factor of four. As a side benefit, the power losses and vibration common to all reciprocating engines are eliminated.
The present invention is directed to a Circle-Ellipse Engine, hereinafter referred to as a the device, capable of various implementations such as an engine, a pump, a compressor, or an expander, each having the following general features: (a) first and second chamber paths allowing for a plurality of chambers to be formed between adjacent Vanes; (b) the Housing cam surface and Rotor form parts of the chamber, and the Vanes driven off a pin track on each End Plate; and (c) the volume of each of the chambers dynamically changes as the as the Rotor turns with respect to the Housing's cam surface. The ability to rapidly change the volume of the chambers, and eliminate leakage between the chambers and other cavities, is crucial to the successful implementation of the device.
Referring to the figures and first to
Please refer next to
Two identical water plenums, upper 105 and lower 140, provide for passage of cooling water from the external water fitting locations, respectively upper 150 and lower 170. The cooling water is then directed to appropriate water passageways in the Housing to provide thermal stability of the Housing 400.
Items 110 and 145 are the inside and outside locations for one of the 16 socket head screws to fasten the End Plates 100 and 100A to each end of the Housing 400.
Item 115 is a cavity suitable for securely mounting thrust and roller bearings respectively in each End Plate 100 and 100A. By mounting the bearings on the inside of the End Plates, secure mounting is assured.
Item 120 is a pin track. It is a calculated tool path based on complex transcendental mathematics. It serves to exactly position the Vanes such that they are maintained a constant distance from the inner cam surface of the Housing 400, Item 455, for all angular positions of the Rotor 300.
Item 125 is one of two locations for accurately positioning a hard pin. The two pins serve to precisely locate the End Plates with regards to the Housing, ensuring proper alignment during assembly.
Items 130 and 165 are the inside and outside locations for one of four identical air inlet/exhaust fittings. These convey passage of air/exhaust to/from the inside of the elliptical cam surface of the Housing 400, Item 455.
Item 140 is one of two identical mounting holes, appropriate for securing the device to a suitable base.
Items 155 and 175 are two of the identical six pre-threaded hard points for attaching accessories, such as an alternator, water pump, oil pump, and/or power steering pump as needed. These accessories are not part of the device.
Item 160 is one of two identical pre-threaded lubrication ports for attaching flow restrictors. These flow restrictors provide for a precise and minimal amount of oil to lubricate the pin track 120.
Please refer next to
Item 205 provides mounting provisions for the apex seal. Its function is identical to that of the Mazda engine, namely to seal high pressure in a combustion chamber from leaking to another chamber.
Item 210 is one of many internal lubrication ports, which guide lubrication oil from the source, Rotor 300, to each external surface of the Vane, Item 200. These pre-drilled ports provide for a precise and minimal amount of oil to lubricate the Vane interface with the End Plates, respectively 100 and 100A, the Rotor 100 Vane slots (
Item 215 is the pin that interfaces respectively with the pin tracks in End Plates 100 and 100A. The pin serves to precisely control the position of the Vane 200 based on its instantaneous position of the Rotor 300.
Please refer next to
Item 305 is one of 12 identical combustion surfaces. During rotation, when this surface is closest to the inside, surface of the Housing 400, Item 455, there is maximum compression. At this point there is minimum extension of a pair of adjacent the Vanes 200.
Item 310 is one of 24 identical side seal slots. When populated with side seals, these slots ensure positive and low friction sealing of the radial Vanes in the combustion chamber. This prevents the leakage of combustion products into lubrication oil, contaminating the oil, and leakage of unwanted oil into the combustion chamber to help minimize Nitrogen-Oxygen (NOx) pollutants.
Item 315 is one of 12 identical Vane slots. When populated with Vanes 200, these slots ensure positive and low friction radial motion of the Vanes. The slots are sealed on both ends respectively by End Plates 100 and 100A.
Item 320 is one of 12 identical lubrication oil chambers. These provide appropriate amounts of lubricating oil and thermal cooling to each Vane slot and the Rotor 300 that interfaces with both End Plates 100 and 100A.
Item 325 is one of 144 identical lubrication ports that provide lubrication oil to each of the 12 identical lubrication oil chambers 320, and each of the 12 Vane slots 315. Each of the chambers and slots contain 6 entry ports, which provide even distribution of lubrication oil throughout the device.
Item 330 is the location of one of the 144 lubrication ports. In conjunction with the driveshaft 500, these ports are the exit locations of the Rotor manifold, which is fed from the hallow driveshaft 500.
Please refer next to
Item 405 is the spark plug port. For the diesel engine implementation of this device, it is the location of the fuel injector.
Item 410 is one of 16 identical threaded holes to accommodate socket head mounting screws that secure the End Plates 100 and 100A to the Housing.
Item 415 is a cooling water passageway. It is a direct interface to the water source port, End Plate Item 150 which in turn feeds supplies the upper End Plate water distribution manifold Item 105. The extensive size of the passageway is to provide thermal stability to the Housing 400.
Item 420 is one of two identical internal lubrication oil distribution tracks that lubricate the working surface of the apex seals discussed earlier, as part of Vane 200 Item 205.
Item 425 is one of two identical external ports for the attachment of oil flow restrictors, which in turn feel lubrication oil to oil distribution tracks Item 420. The flow restrictors are selected to ensure proper oil lubrication is applied to the apex seals, and minimize the amount of unwanted oil into the combustion chamber to help minimize Nitrogen-Oxygen (NOx) pollutants.
Item 430 is one of 36 air/exhaust ports that connect air/exhaust from the End Plates 100 and 100A Items 130 and 165, through the Housing Item 445 and into the inside elliptical cam surface of the Housing 400, Item 455. The ports are arranged in four segments of 9 openings each. This is to minimize the disruption and wear on the apex seals, ensure even distribution, and define the proper distanced between an adjacent pair of Vanes 200.
Item 435 is one of two locations for accurately positioning a hard pin. The two pins serve to precisely locate the End Plates Item 125 with regards to the Housing, ensuring proper alignment during assembly.
Item 440 is the lubrication oil exit port. The lubrication oil that enters each of the Item 425 ports is swept into the internal lubrication oil scavenge track and drained into the oil sump, which is not part of the device. Scavenged oil foam is removed by baffles in the sump, before it is respectively conveyed to an oil filter and pump.
Item 445 is the mating location for each of the four identical air/exhaust ports to/from the End Plates 100 and 100A Items 130 and 165. These convey passage of air/exhaust to/from the inside of the elliptical cam surface of Item 430 of the Housing 400.
Item 450 is one of eight identical cooling water passageways. It is a direct interface to the water source port, End Plate Item 135 which in turn feeds lower End Plate water distribution manifold Item 135. The extensive size of the passageway is to provide thermal stability to the Housing 400.
Item 455 is the inside elliptical cam surface of the Housing 400. The geometry is a classical ellipse with a major and minor axis. This simple cam surface supersedes all complex, prior attempts to satisfy the requirement for a continuously changing height of the combustion chamber. Prior efforts included complex sinusoidal implementations, which were characterized by high acceleration ramp changes. Unfortunately, these resulted in intensive wear patterns, including chatter, gouging, and ripple effects on the ramp. Complex lubrication was requiring for these implementations, resulting in residual oil in the combustion chamber which lead to excessive nitrogen-oxygen (NOx) products.
Please refer next to
Item 505 is a spline section of the Drive Shaft. It has a standard 16 rib spline compatible with many devices (transmissions, gear boxes, etc.).
Items 510 and 530 serve an identical purpose. They provide a line-to-line press-fit interface for the bearings, which are housed inside the End Plates in a cavity Item 115.
Items 515 and 525 provide a line-to-line press-fit interface for the Rotor 300.
This section between the two collars has a slightly reduced diameter and forms the opposite ends of an oil manifold.
Item 520 is the oil manifold. It provides symmetrical distribution of cooling and lubricating oil to the Rotor 300 through 144 ports discussed earlier as Item 325 which is part of Rotor 300.
Item 535 is a section of the Drive shaft that supports the attachment of a commercial rotary union. The rotary union facilitates connection of cooling and lubricating oil to the rotating Drive Shaft.
Items 540, 545, and 550 are shown in the cut-away view of the Drive Shaft 500 and are interrelated to the injection and distribution of cooling and lubricating oil. Item 550 is the inlet port, which is mated with the commercial rotary union discussed in the prior paragraph. Item 545 is the internal passageway that connects the inlet to outlet port 540. The outlet port is located in the center of the Rotor 300 manifold, and distributes oil to the 144 ports of the Rotor, Item 330.
Item 555 are groves in the Drive Shaft that provide the structure for installation of O-rings to seal the sides of the commercial rotary union to the driveshaft and eliminate oil leakage.
Item 560 is a threaded hole for an end cap. In order to machine the internal passageway Item 545 in Drive Shaft 500, an access means is required. After machining, a commercial screw cap is used to seal the opening.
Please refer next to
The six-sided chambers are formed by the inner cam surface of Housing 400, Rotor 300, a pair of adjacent Vanes 200, and (not shown) End Plates 100 and 100A.
As the Rotor 300 turns clockwise, the combustion chamber pointed by Index A is a very small, expanding chamber which is manifest when Rotor 300 passes the top-center of the inner cam surface, just past the top of elliptical minor axis.
As the Rotor continues to turn clockwise, the chamber expands, as shown by Index B.
At maximum chamber height, as shown by Index C, occurs when Rotor reaches a horizontal position of the inner cam surface, which is the elliptical major axis.
As the Rotor continues to turn clockwise, the cycle repeats these steps in reverse sequence.
Index D is a related feature. It is pointing to Pin 215 of Vane 200. This pin is assembled into pin track 120 of End Plates 100 and 100A. It is this pin track that determines radial Vane 200 position, and its extension beyond the perimeter of Rotor 300.
It will be understood by a person skilled in the art that although the device shown in
While preferred embodiments of the present invention have been described, it is to be understood that the embodiments described are illustrative only and the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalence, many variations and modifications naturally occurring to those of skill in the art from a perusal hereof. As is readily, apparent the system and method of the present invention is advantageous in several aspects.
