Patent Application
20060288977
Not applicable
Not applicable
Not applicable
This invention pertains to certain improvements in rotary internal combustion engines in general and nutating engines in particular.
For more than a century engineers have had a dream of replacing the reciprocating piston engine with a rotary piston device. It had been hoped that by so doing the inherently stressful conditions of reciprocation could be obviated providing for a far less massive construction and a smoother action. The effort has met with limited success: the only palpable effort has been the Wankel Drehkolbenmotor which became operational in a commercial sense only after the prodigious effort on the part of metallurgists on three continents. The problem, of course, was the seals.
Another thread of design has been the nutating engine in general and the spherical engine in particular. The hope was that by availing oneself of the natural motion as analyzed by Leonard Euler in 1760 of a symmetric body, namely the uniform rotation of this body as its axis of rotation simultaneously precesses, i.e., sweeps out a cone shape in three dimensional space, that the aforementioned stressless condition might might be realized.
To manifest this idea most efforts have sought to enclose the process within the confines of a spherical cavity. This could immediately nullify the “Newtonian” stress by fixing the center of mass of the main displacement element, i.e. that which is analogous to the piston, at the sphere's center. (The Wankel does not share this benefit.) This relief however comes with a heavy bill to pay: Given that both the spherical cavity and the main displacement member are of constant volume, certainly what remains can not be naively utilized as a combustion chamber for its volume must, throughout the cycling, likewise remain constant.
To allay this predicament, the spherical combustion chamber has, over the century, seen itself partitioned in one way or another, always to Pyrrhic effect:
Typically in Meyer U.S. Pat. No. 5,251,594; Oct. 12, 1993 the partition necessitates the slotting of the main displacement member to the effect of precluding its actual rotation. With this there is no possibility of recovering any kind of hitherto mentioned, natural motion. Additionally the sealing problem is far greater than for even the Wankel.
Millet U.S. Pat. No. 6,325,038 B1; Dec. 4, 2001 cleverly skews the drive shaft at some angle to the combustion chamber axis rendering the chamber amenable to partition. Though the sealing problem is far more tractable than Meyer there is again no rotation of the main displacement element and so no possibility of exploiting a natural motion.
Lim U.S. Pat. No. 5,336,067; Aug. 9, 1994 is a spherical engine of a different nature. By utilizing two sequences of cusps which slide over each other within the spherical cavity he at least holds out the hope for manifesting a simultaneous natural rotation and precession of the main displacement elements though he makes no mention of this. Then, to alleviate wear and tear upon these cusps he introduces vaguely certain cams and cam followers not aware, apparently, of the corresponding loss in seal integrity that that would necessarily occasion.
The instant invention is in some way similar to Lim and in some way its diametric opposite.
I submit a nutating engine in which, between inner and outer concentric spherical surfaces, according to one aspect of the instant invention, a progression of free-planetary gears are engaged with and only with both a substantially circular toothed Rotator as well as a toothed Nutating Member possessing some number of lobes and an equal number of interjacent arches, this number being different by unity to the number of free-planetary gears. In circumnavigating their latitude the phase lag of each free-planetary gear relative to the lobe's nadir subsequent to it will increment uniformly. Additionally, all phase lags will together advance with advancing time. Thus entrained, the Nutating Member will be enjoined to execute perfect geometrical rotations and simultaneous precessions relative to the Rotator.
This motion will occasion the inter-planetary volumes to suffer expansions and contractions thus defining them as combustion chambers.
According to another aspect of the instant invention, the Nutating Member can be counterweighted to relocate its center of mass to that of the sphere whence the entire apparatus be imparted with a reverse-English about the Rotator's axis thus endowing the formerly mere geometrical precession with a natural-physical (as per Euler) character. Adding the observation that both the Rotator and the free-planetary gears describe but circles the overall result is an extremely stress-free, lightweight, easily sealed, and easily milled device. Finally, while the cavitation provided by the gearing will yield a high burn efficiency, the insertion of “butterflies” into the inter-planetary volumes will coax the compression ratio to well within the Diesel regime.
The instant invention utilizes not a cusped but a lobed curve called the polaricider which demarcates the Nutating Member, the main displacement element. This plus a Rotator and not fixed cams, but a sequence of free-planetary gears define the combustion chambers.
So, one object of the proposed invention is to lay to rest the sealing problem: the tighter the entrainment of rotating elements the greater the seal integrity.
A much greater object is to render all of the combustion elements with a completely natural, stress-free motion, as will be seen infra. This will allow an unbelievably light-weight construction.
A third object is to reduce wear, tear, and maintenance to levels commensurate with those of electric motors.
Several other objects and advantages will become apparent in the succeeding argument.
It is acknowledged at the outset that the description offered of the instant invention together with certain unavoidable philosophical digressions is far more complicated than its operation which is really no different than a rotary version of a four-stroke piston engine. On the other hand this complexity is completely canonical in the sense that it flows freely from the main engendering principle: to exploit as combustion chambers the varying volumes associated with a completely stress-free precessional process.
The composition of the engine divides itself naturally into two main assemblies: the spherical (in this preferred embodiment: upper) and the strictly rotating (in this preferred embodiment: lower).
As for the former, what immediately follows (see
Geometrical Digression
The Nutating Member is a novel structure. The pitch surface which demarcates it is called a polaricider. It is defined primarily almost tautologically as that curve which will role without slipping over the pitch cone of a free-planetary gear, itself rolling without slipping over the pitch cone of the Rotator as the latter executes a perfect geometrical rotation and simultaneous precession relative to the Nutating Member. This exercise induces on the polaricider a number of symmetries: Each projecting lobe must be identical to every other and must possess in itself perfect mirror symmetry. The same is true of each interjacent arch. Any Nutating Member can be gauged by the angle subtended at the sphere's center between the Nutating Member's pole (see
In that the free-planetary gears are indeed free and doubly engaged the polaricider bears no relationship to a cycloid, nor any involute, evolute, nor any spherical analogue thereof.
By “rotation and simultaneous precession” is meant the lay notion of an object spinning uniformly about its symmetry axis as this axis uniformly rotates about a secondary (in this embodiment: vertical) axis (see
Once the existence and uniqueness of the polaricider is apprehended it seems amazing that some number of free-planetary gears can be simultaneously entrained between the Rotator and the Nutating Member. Actually it is trivial: On the surface of the inner spherical cover entrain a single free-planetary gear with the Rotator and initially, say, the nadir of a lobe of the Nutating Member therewith tilting that lobe maximally away from the Rotator. Now let the entrainment run its course according to the design criterion. As each subsequent lobe arrives at its maximal distance from the Rotator entrain yet another free-planetary gear. Obviously, only a number of free-planetary gears different by one to the number of lobes as specified by the design parameters can be accommodated. When this number has been reached the resulting configuration will be as
Static Description (Cont.)
Thus far the physics of the Nutating Member is anything but stress-free. To achieve half that goal counterweight arms 11A, 11B, 12A, and 12B are affixed to the Nutating Member well free of the outer spherical cover. Their primary function is to relocate the Member's center of mass to that of the sphere. Still, the rotational motion will be unnatural: For most reasonable configurations (but not all; see the alternate embodiment infra) the Nutating Member's precession will have the opposite sense as its rotation (see
The entire rotational assembly is built on three hollow concentric lumena (see
Rotator shaft 18 is sustained upon stationary shaft 17 on an inward projecting lip 21 the lower surface of which comprises a seal 34 which in spite of its spinning prevents loss of charge as it passes up through stationary shaft 17 before exiting towards a combustion chamber via a spiracle 35. The Rotator shaft is also affixed with a sprocket gear 15.
An outermost hollow shaft 22 governs the cams and distributor. Its lower region is affixed with a sprocket gear 23 and sustained upon Rotator shaft 18 on an outward projecting lip 25. Its upper region extends as far as the cam and distributor canister whose inner workings are responsible for exhausting, charging, and igniting the inter-planetary combustion chambers. Though electrical slip rings 26 and 27 are depicted at the base of the Rotator shaft, the electrical system including any cams and/or microprocessors that might be utilized in the ignition process is assumed to be a well understood art, reside completely within the confines of the canister and is completely suppressed from the drawings.
Although the rotation and simultaneous precession of the Nutating Member relative to the Rotator in
The only place besides this common drive shaft where the two assemblies communicate with each other is via the components that oversee the functioning of any including the instant internal combustion engine. Hence, the top of cam shaft 22 is affixed via struts to an exhaust valve cam 32 and this to an intake valve cam 31. Each cam has a central circular cut-out to make way for Rotator shaft 18 which was previously described as fixed to the canister with which it rotates. Turning to
Design Considerations
Thus far each engine can be characterized by three continuous and one integer parameters. To reiterate: the subtended angle at the sphere's center of a free-planetary gear, the Rotator, and the Nutating Member plus the number of lobes. In point of fact one of the continuous parameters must be absorbed to facilitate the condition that the compression ratio be fixed at a relatively high value, i.e. that each lobe have approximately the same (though somewhat less) extent than a free-planetary gear. (see
Static Description (Cont.)
To further boost the compression ratio plugs can be optionally inserted into the inter-planetary volumes (see
Operation
As promised the operation is trivial. As each inter-planetary volume becomes bounded (in this embodiment: from above) sequentially by a lobe, an arch, a lobe, an arch, and a lobe, that volume undergoes the familiar cycling of the four-stroke piston engine: intake, compression, power, and exhaust. It only remains to say with respect to the 5 inter-planetary volumes that successive, say, ignitions follow a pentagrammic pattern while with respect to the 7 spark plug stations the ignitions follow a less-tight septagrammic pattern. (I.e., if I may hearken back to high school: not the more-tight septagrammic pattern of successive multiples of 3 modulo 7, but the less-tight septagrammic pattern of successive multiples of 2 modulo 7; or equivalently, successive multiples of 200 modulo 700.) In other words, in this embodiment the ignition is completely even-tempered with respect to both the inter-planetary volumes and the spark plug stations.
It is somewhat amazing that this latter regimen can be effected with just a three-pointed cam but consultation with the highly schematicized
As will be posited in the succeeding section there are numerous variations that can be played on this preferred theme. One alternate embodiment which simultaneously incorporates several of these is for the two main gear elements to take each other's place:
In
Additional Scope
There are many variations that may prove advantageous. One, in the realm of hydro- or especially aero-dynamics, is that instead of conveying torque to a common remote drive shaft that there might be certain advantages in affixing a propeller or an impeller directly to the Nutating Member. Another is that the previously mentioned ratio of rotations of the Nutating Member and the Rotator Shaft (not to mention the Cam Shaft) should not be thought to be constrained to non-zero and non-infinite values: Certainly one or more may be frozen with respect to the engine's reference frame. Indeed, this was the case of the “Rotator” in the alternate embodiment.
Furthermore, the means by which this ratio is held fixed need not be sprocket gears linked to a common drive shaft. Various pinion gears, conical gears, belts, and such could easily be substituted.
In addition it might be, as in the case of the modern bicycle, that certain advantages may be reaped in certain departures from perfect roundness in regards to the sprocket gears. This may also be true of the free-planetary gears especially if coordinated with some periodicity as they traverse around the Nutating Member and the substantially circular Rotator. Even the latter might absorb some of the precessional duties by assuming a lobedness. Again, this was exactly the case in the alternate embodiment in which the (stationary) “Rotator” was the only lobed element.
There are an infinitude of variations possible so the essence of the instant invention must be attributed to not the two embodiments nor these recent musings but strictly to the claims.
