Patent Grant
6945217
The present invention relates to rotary machines, including rotary engines, rotary motors, and compressors.
The advent of rotary engines was intended to supplant reciprocating engines, thereby to reduce energy losses caused by the reciprocation of pistons, to reduce the number of moving parts, and also, friction losses. In this way it was intended to increase the number of revolutions per minute, and also to increase engine efficiency.
Rotary engines may include a pair of rotors arranged for rotation within a sealed engine cavity. The rotors are connected to an output shaft or driver. A combustible fuel mixture is provided to the engine cavity and ignited. An increase in pressure in the engine cavity due to ignition of the fuel-air mixture results in a driving force being applied to the rotors, thereby causing rotation of the driver.
There are also known rotary pumps and motors which have certain similarities to the above-described engine. An indication of the state of the art may be obtained by referring to the following patent publications:
U.S. Pat. No. 3,078,807, entitled Dual-Action Displacement Pump;
French Patent No. 9204757, publication no. 2,690,201;
U.S. Pat. No. 3,726,617, entitled Pump or a Motor Employing a Couple of Rotors in the Shape of Cylinders with an Approximately Cyclic Section; and
U.S. Pat. No. 5,152,683, entitled Double Rotary Piston Positive Displacement Pump with Variable Offset Transmission Means.
The above patents generally do not provide structures which are conducive for use as internal combustion engines.
In the field of internal combustion engines, it is desirable to sustain high operating temperatures, thereby to maximize engine efficiency, in accordance with the well-known Carnot Law.
In the field of rotary internal combustion engines, there are known the following publications: U.S. Pat. No. 2,845,909, entitled Rotary Piston Engine, to Pitkanen; and U.S. Pat. No. 4,666,383, entitled Rotary Machine, to Mendler.
Pitkanen teaches a rotary piston engine having a pair of cam-shaped rotors which are arranged for parallel rotation inside an engine casing. Pitkanen is unable to work at high speeds due to the shape of the rotors, and, furthermore, seeks to cool the engine, thereby preventing an increase in temperature which, in Pitkanen's engine, is undesired. This results in an inefficient engine, based on the well-known Carnot Law, in which efficiency is proportional to the temperature difference between the interior and exterior of the engine, which Pitkanen does not sustain.
Mendler teaches a rotary piston engine having a pair of cam-shaped rotors which are arranged for parallel rotation inside an engine casing. Each rotor is described in the cited patent (column 8, lines 1-6) as having “major and minor cylindrical surfaces . . . , each centered on the axis A of the rotor, and diametrically opposed, . . . joined by cylindrical transition surfaces . . . ” Furthermore, a plurality of seals are provided, thereby to provide rotor-to-rotor and rotor-to-bore-wall seals (column 7, lines 62-64). It will be appreciated that, due to the presence of seals, the engine taught by Mendler is not only unable to sustain high rotational speeds, due to friction losses, but also cannot operate at high temperatures, due to the necessary presence of lubricating oil in the engine cavity.
The term “non-touching seal” is used to mean a non-physical barrier in a dynamic situation in which a working fluid is confined between a plurality of surfaces for a specified period of time, wherein at least one of the surfaces is in motion relative to the other and is spaced apart therefrom across a gap of predetermined dimensions, and wherein the dimensions of the gap and the relative velocity therebetween combine so as to prevent significant leakage of working fluid therepast, during the specified period of time. This is in contradistinction to dynamic seals which rely, solely or partially, on the presence of an additional sealing element to be in touching contact with a surface past which it is sought to prevent leakage of a working fluid.
The present invention seeks to provide a rotary machine which embodies yet further improvements in rotary machine operation, beyond those claimed and described in applicant's U.S. Pat. No. 6,250,278 and co-pending application U.S. Ser. No. 09/887,060 entitled Improved Rotary Machine, filed 25 Jun. 2001, now U.S. Pat. No. 6,604,503 to Mekler, and now entitled Rotary Machine, the contents of which are incorporated herein, by reference.
In particular, the present invention seeks to provide a non-cylindrical rotor construction and a rotary machine employing pairs of such rotors, which facilitate the attainment of an elevated compression ratio, together with an attendant increase in fuel efficiency.
Additional advantages will become apparent from the following description.
There is thus provided, in accordance with a preferred embodiment of the invention, a rotor for use with a rotary machine, wherein the rotor includes a pair of parallel side surfaces; and a curved perimeter surface formed between the pair of parallel side surfaces, formed of a plurality of curved portions, each abutted by a pair of the curved portions, contiguous therewith and mutually tangential thereto.
Additionally in accordance with a preferred embodiment of the present invention, the curved perimeter surface includes:
a major portion defining a first major arc subtending a predetermined angle at a predetermined center of rotation, and having a first radius;
a minor portion defining a first minor arc subtending a predetermined angle at the predetermined center of rotation, and having a second radius, shorter than the first radius, the major and minor arcs being arranged along an axis of symmetry; and
a pair of similar, intervening curved portions extending tangentially between major and minor arcs.
Further in accordance with a preferred embodiment of the present invention, each pair of intervening curved portions is formed of a second major arc and a second minor arc, of predetermined radii.
Additionally in accordance with a preferred embodiment of the present invention, the curved perimeter surface is shaped such that when mounted for coplanar, non-touching, and same-directional rotation with another rotor of identical construction, and wherein the rotors have mutually parallel orientations at the start of rotation, and are rotated at the same angular velocity, the curved perimeter surface of the rotor is separated from the curved perimeter surface of the other rotor by a predetermined, fixed distance.
Further in accordance with a preferred embodiment of the present invention, each rotor has a geometric center, and the distance therebetween equals R1+R2, wherein R1 is the radius of the first major arc and R2 is the radius of the second minor arc.
There is also provided, in accordance with an alternative embodiment of the invention, an improved rotary machine which includes:
a housing having formed therein a generally elongate cavity, the cavity being formed by a pair of adjoining, partially overlapping cylindrical bores, each bore being separated from an adjoining bore by a pair of non-joining partition walls;
a pair of non-cylindrical rotors arranged in the pair of adjoining bores, each rotor having a curved perimeter surface formed of a plurality of contiguous mutually tangential curved portions, wherein each rotor is disposed in one of the bores for synchronized, non-touching and same-directional rotation with the other of the pair of rotors;
a pair of rotor shafts associated with each pair of rotors, each rotor shaft extending through one of the bores, and mounted transversely to each rotor so as to provide rotation thereof in the bore;
a gear assembly and a driver associated with the rotor shafts, the assembly and the driver, cooperating to provide synchronized same directional rotation of the rotor shafts;
one or more pairs of intake gas ports formed in the housing and communicating with the elongate cavity thereof, for permitting selectable intake of working gases;
one or more pairs of exhaust gas ports formed in the housing and communicating with the elongate cavity thereof, for permitting selectable exhausting of working gases, wherein, introduction of a working gas into interactive association with the rotors causes rotation of the pair of rotors and thus also of the driver; and
shutter apparatus mounted so as to normally close one or more predetermined gas ports so as to prevent gas flow therethrough.
Preferably, the rotary machine is operable to achieve a compression ratio of at least 1:30.
Additionally in accordance with a preferred embodiment of the present invention, the shutter apparatus is mounted in association with one or more of the exhaust gas ports so as to so as to prevent gas flow therethrough.
Further in accordance with a preferred embodiment of the present invention, the shutter apparatus is mounted in association with one or more of the exhaust gas ports so as to normally close the port and thereby to prevent gas communication between the one or more exhaust gas ports and the interior of the elongate cavity, the shutter apparatus being selectably operable to uncover the exhaust gas port, thereby to permit selectable exhausting of working gases.
Additionally in accordance with a preferred embodiment of the present invention, the shutter apparatus includes a pair of shutter elements, each mounted onto a respective one of the rotor shafts, for rotation therewith.
Further in accordance with a preferred embodiment of the present invention, the working gas is atmospheric air, and the housing has formed therein an atmospheric air inlet for conducting air from the atmosphere to the one or more pairs of gas intake ports, and wherein the machine further includes supercharger apparatus arranged in association with the atmospheric air inlet for elevating the pressure of the air supplied to the gas intake ports to above atmospheric.
Additionally in accordance with a preferred embodiment of the present invention, the supercharger apparatus includes a pair of supercharger elements, each operative to be driven by a respective one of the rotor shafts.
Further in accordance with a preferred embodiment of the present invention, the supercharger element is mounted onto one of the rotor shafts for rotation therewith.
Additionally in accordance with a preferred embodiment of the present invention, each bore has a geometric center, and each rotor is eccentrically mounted for rotation about a rotation axis located in the center of the bore, each cavity is bounded by a pair of parallel wall surfaces transverse to the rotation axis; a first of the gas ports is arranged at a first radius from the geometric center and a second of the gas ports is arranged at a second radius from the geometric center, wherein the second radius has a magnitude smaller than that of the first radius; and each rotor is operative to rotate within one of the bores so as to periodically uncover the first port, thereby to enable a flow therethrough of a working gas.
Further in accordance with a preferred embodiment of the present invention, the pair of rotors are disposed in equal angular orientation relative to their rotation axes.
Additionally in accordance with a preferred embodiment of the present invention, each rotor has a pair of flat, parallel surfaces disposed in dynamic, non-touching, sealing relation with the pair of parallel wall surfaces of each cavity, and each rotor has formed therein a throughflow portion which is formed so as to be brought periodically into communicative association with the interior of the cavity and with the second gas port, so as to facilitate gas communication therebetween.
Further in accordance with a preferred embodiment of the present invention, each pair of rotors includes first and second rotors arranged for rotation within a predetermined pair of adjoining, respective, first and second bores such that the perimeter surfaces of the first and second rotors are always in dynamic, non-touching, sealing relation with each other.
Additionally in accordance with a preferred embodiment of the present invention, the machine is an internal combustion engine, and the rotors are operative, during the rotation thereof, to cooperate with the partition walls and predetermined portions of the side walls so as to periodically form combustion chambers therewith, and wherein the housing and the rotors are formed of a substantially non-heat conducting material, thereby to enable an elevated temperature to be sustained within the combustion chambers during operation of the engine.
Further in accordance with a preferred embodiment of the present invention, the elevated temperature, once attained during operation of the engine, is sufficient to cause combustion of an air-fuel mixture in the combustion chambers, even in the absence of an air compression ratio of greater than 1:14.
Additionally in accordance with a preferred embodiment of the present invention, the substantially non-heat conducting material is a ceramic material.
Further in accordance with a preferred embodiment of the present invention, the first port is a working gas intake port, and the second port is a working gas exhaust port, and wherein each pair of rotors are operative to rotate through a working cycle having first and second portions,
wherein, during the first portion of the working cycle,
the first and second rotors are operative to rotate into first positions whereat they are initially spaced from a first side of the cavity so as to define a first working space therewith, and the first rotor is operative to uncover the working gas intake port in the first bore thereby to admit air into the space;
the first rotors and second rotors are operative to rotate into second positions so as to reduce the volume of the first working space and thus compress the working gas therein; and
the first rotors and second rotors are operative to be rotated into third positions in response to an expansion of the working gas in the first working space, and such that the second rotor is operative to bring the throughflow portion thereof into communicative association with the interior of the cavity and with the exhaust port in the second bore, so as to facilitate exhausting of working gas from the second working space.
and wherein, during the second portion of the working cycle,
the first and second rotors are operative to rotate into fourth positions whereat they are initially spaced from a second side of the cavity, opposite the first side of the cavity, so as to define a second working space therewith, and the second rotor is operative to uncover the working gas intake port in the second bore thereby to admit air into the second working space;
the first rotors and second rotors are operative to rotate into fifth positions so as to reduce the volume of the second working space and thus compress the working gas therein; and
the first rotors and second rotors are operative to rotate into sixth positions so as to permit expansion of the working gas in the second working space, and such that the first rotor is operative to bring the throughflow portion thereof into communicative association with the interior of the cavity and with the exhaust port in the first bore, so as to facilitate exhausting of working gas from the second working space.
Additionally in accordance with a preferred embodiment of the present invention, during the first portion of the working cycle, as the first rotors and second rotors rotate into the third positions, the first rotor is operative to uncover the intake port in the first bore, thereby to permit a throughflow between the intake port in the first bore, the first working space, the throughflow portion of the second rotor, and the exhaust port in the second bore;
and during the second portion of the working cycle, as the first rotors and second rotors rotate into the sixth positions, the second rotor is operative to uncover the intake port in the second bore, thereby to permit a throughflow between the intake port in the second bore, the second working space, the throughflow portion of the first rotor, and the exhaust port in the first bore.
Further in accordance with a preferred embodiment of the present invention, the machine is an internal combustion engine, the first and second working spaces are first and second combustion chambers, the working gas intake ports are air intake ports, and the working gas exhaust ports are combustion gas exhaust ports,
and wherein the machine also includes at least first and second fuel injectors for injecting fuel into the first and second combustion chambers so as to provide fuel-air mixtures therein and so also as to enable combustion of the fuel-air mixtures, thereby to provide a rotational force on the second rotor during the first portion of the working cycle, and on the first rotor during the second portion of the working cycle.
Additionally in accordance with a preferred embodiment of the present invention, there is also provided ignition apparatus associated with the first and second combustion chambers, for selectably igniting the fuel-air mixtures therein.
In accordance with a further alternative of the invention, the machine is a motor, associable with an external source of pressurized working gas, wherein the rotation axis passes through the geometric center of a respective one of the bores, and each rotor is eccentrically mounted for rotation about the rotation axis;
each cavity is bounded by a pair of parallel wall surfaces transverse to the rotation axis;
the plurality of gas ports includes at least a pair of gas ports provided in each bore, wherein a first of the gas ports is arranged at a first radius from the geometric center and a second of the gas ports is arranged at a second radius from the geometric center, wherein the second radius has a magnitude larger than that of the first radius; and
wherein each rotor is operative to rotate within one of the bores so as to periodically uncover the second port, thereby to enable a flow therethrough of a working gas.
Additionally in accordance with the further alternative embodiment of the present invention, each rotor has a pair of flat, parallel surfaces disposed in dynamic, non-touching, sealing relation with the pair of parallel wall surfaces of each cavity, and each rotor has formed therein a throughflow portion which is formed so as to be brought periodically into communicative association with the interior of the cavity and with the first gas port, so as to facilitate gas communication therebetween.
Furthermore, each pair of rotors includes first and second rotors, each arranged for rotation within a predetermined pair of adjoining, respective, first and second bores such that the perimeter surfaces of the first and second rotors are always in dynamic, non-touching, sealing relation with each other.
In addition, the first port is a pressurized working gas intake port, and the second port is a working gas exhaust port.
In accordance with yet a further alternative embodiment of the invention, the machine is a compressor, associable with an external source of working gas, wherein the rotation axis passes through the geometric center of a respective one of the bores, and each rotor is eccentrically mounted for rotation about the rotation axis;
each cavity is bounded by a pair of parallel wall surfaces transverse to the rotation axis;
the plurality of gas ports includes at least a pair of gas ports provided in each bore, wherein a first of the gas ports is arranged at a first radius from the geometric center and a second of the gas ports is arranged at a second radius from the geometric center, wherein the second radius has a magnitude larger than that of the first radius; and
wherein each rotor is operative to rotate within one of the bores so as to periodically uncover the second port, thereby to enable a flow therethrough of a working gas.
Furthermore, each rotor has a pair of flat, parallel surfaces disposed in dynamic, non-touching, sealing relation with the pair of parallel wall surfaces of each cavity, and each rotor has formed therein a throughflow portion which is formed so as to be brought periodically into communicative association with the interior of the cavity and with the first gas port, so as to facilitate gas communication therebetween.
In addition, each pair of rotors includes first and second rotors, each pair of rotors being arranged for rotation within a predetermined pair of adjoining, respective, first and second bores such that the perimeter surfaces of the first and second rotors are always in dynamic, non-touching, sealing relation with each other.
Moreover, the second port is a working gas intake port, and the first port is a pressurized working gas exhaust port.
In accordance with an additional embodiment of the present invention, there is provided a rotary machine for producing energy from a working fluid which includes:
a body having therein a working cavity;
a working fluid intake formed in the body, for permitting intake of a working fluid into the working cavity;
a working fluid exhaust formed in the body, for permitting exhausting of a working fluid from the working cavity;
rotary working apparatus operable to be driven in the presence of working fluid in the cavity, including apparatus for compressing the working fluid therewithin, capable of achieving a compression ratio of at least 1:30.
The present invention will be more fully understood and appreciated from the following detailed description, taken in conjunction with the drawings, in which:
Referring now to
For the purpose of clarity, all portions and components of the machine which are described herein with regard to
Returning now to
Body 12 is subdivided, in the present examples, into two rotor units, referenced generally R1 and R2. As seen in
As seen in
Located within each pair of inner and outer partition walls 38′ and 38 is a shutter element, a lower shutter element being indicated by reference numeral 85a′ and an upper shutter element being indicated by reference numeral 85a″. As seen schematically in
While not all the machines shown and described hereinbelow are specifically shown or described as having shutter elements 85, it is a particular feature of the present invention that, all such embodiments preferably employ the shutter elements or equivalents thereof, for the above-stated purpose.
It will be appreciated from the description below, that while pressures in the working chambers are very high, shutter elements 85 are at no time exposed to these pressures due to the non-touching seals by which the interior of working chambers is completely sealed, shown and described hereinbelow, inter alia, in conjunction with FIG. 8.
As seen in
Manifold and distributor unit 26 has a working fluid intake 27 which is connected via a plurality of inlet conduits, depicted schematically at 29, for supplying a working fluid, typically atmospheric air, to the working cavities; and an exhaust fluid outlet 31, for exhausting exhaust gases from the working cavities via a plurality of exhaust conduits, depicted schematically at 33.
When machine 10 is constructed as an ICE, the exhaust gases are waste gases resulting from combustion of an air-fuel mixture. When machine 10 is constructed as a motor or compressor, however, the exhausted fluid outlet 31 simply serves to permit egress of the working fluid from the machine.
Referring now also to
For the sake of simplicity, the angular disposition of the rotors is indicated in
As shown in
As seen in
The terms “upper” and “lower” are intended merely to orientate the reader with regard to the disposition of the described portions as they are depicted in the present drawings, and not to define the orientation of the machine when operated.
Referring now particularly to
There is also provided a second pair of bearings 46 which are mounted onto respective shafts 42 and 44 (FIG. 1), and which are located inside appropriately provided openings in partition wall 38 (FIG. 1). A main bushing, referenced 71, is mounted onto each of shafts 42 and 44, and functions as a spacer between the two rotors mounted thereon.
An output shaft or driver, referenced 58, extends typically along longitudinal axis 60 of the machine 10, and through an opening formed in a main bearing 64, which, in the illustrated arrangement, constitutes an outward extension of gear housing 18. A first, free end 66 (seen also in
As seen in
A further benefit of the above-described gear arrangement, is that it enables maintenance of an identical angular disposition of both of rotors A and B in each pair of rotors, as mentioned hereinabove.
It will further be appreciated that, in view of the fact that the respective diameters of spur gears 45 and ring gear 72 are predetermined at a ratio of, for example, 1:4-1:6, this causes a desired reduction in the rotational speed of driver 58.
The function of the bearings described above is to enable rotation of the shafts and gear assembly components with minimal friction, and so as to prevent any longitudinal or radial movement of the rotors and the shafts relative to the machine body, and appropriate bearings are selected in accordance with this requirement. The bushings are operative to provide exact and unvarying spacing of the rotors, bearings, and spur gears. As the gear assembly 20 and associated bearings must be lubricated, appropriate seals (not shown), well known to those skilled in the art, are provided, preventing lubricating fluid from either entering the interior of the rotor housings, or from leaking from any other portion of the machine body.
Referring now briefly to
Preferably, in the present embodiment, the drive belt 120 extends also about a third gear member 245, external to the machine casing, which is drivably associated with a third shaft 142, typically parallel to shafts 42 and 44, and which functions as a power output member or driver. An example of a suitable drive belt is the single-sided synchronous polyurethane belt made by Gates GmbH of Eisenbahnweg 50, D-52068, Aachen, Germany.
An essential feature of the present rotary machine is the provision of exceedingly narrow gaps between the moving parts, namely, the rotors, and the body, and also between the rotors themselves, thereby constituting the “non-touching seals,” seen in FIG. 8 and as described herein. Accordingly, essential requirements are accurate machining of the machine parts, as well as consistent position stability over time.
Accordingly, as seen in
Each of rotor shafts 42 and 44 is a steel shaft having a main portion 53, a pair of end portions 55, and a pair of locking portions 57, located between main portion 53 and end portions 55. Main portion 53 and end portions 55 are of circular cross-section, but main portion 53 has a relatively large diameter, while end portions 55 are of reduced diameter. Locking portions 57 meet main portion 53 so as to define square shoulder portions 59, and are formed so as to be non-circular, preferably square, so as to be lockably engageable with a locking disk 61, seen also in FIG. 3.
Main portion 53 is so dimensioned as to receive the rotors thereon. While the rotors are not directly connected to the shafts 42 and 44, the inner diameter of an opening 63 (
Referring now also to
There are also provided elongate positioning pins 69, formed preferably of steel, which extend through precision formed openings formed along the length of main bushing 71, and terminate in blind recesses 67. Preferably, positioning pins 69 are dimensioned so as not to extend into the full depth of the blind recesses.
Reference is now also made to
In accordance with a preferred embodiment of the invention, there may optionally be provided in each of the rotors, cooling bores 73a, (seen also in
It is thus seen that each rotor train includes a shaft, main bushing 71, a pair of rotors, positioning pins 69 extending through openings formed through bushing 71 and the rotors, and that the rotors are positioned with respect to the shaft, by virtue of the engagement between the blind recesses 67 of locking disks 61, as disks 61 will only fit when properly oriented with respect to the ends of positioning pins 69. Once having been assembled, therefore, no relative rotation can occur among any of these components of each rotor train, such that a rotation of the rotors during operation of the machine, causes a corresponding motion of the shafts and thus also of the driver 58 (FIGS. 1-2).
In order to ensure that the positional integrity of each rotor train is maintained, locking nuts 51 are tightened appropriately, so as to apply, via bushings 75 and bearings 46, axially compressing therebetween the above-mentioned rotor train components. It will be appreciated that, while the interior portions of bearings 46 are locked together angularly, the exterior portions thereof are free to rotate thereabout.
In order to ensure that no less than a desired compression force is applied to the locking disks 61, rotors, and bushing 71, and minimal shear forces are applied to the positioning pins, it is preferable that the length of the main shaft portion 53, i.e. the distance between shoulder portions 59, is less than the combined length of the rotors, and bushing 71, such that no axial compression forces are applied to the shaft via its shoulder portions 59.
Referring now once again to
In order to prevent a dynamic imbalance from occurring as the rotor is rotated, mass is removed from the major portion R1, by way of providing hollow spaces therein, referenced 77; and mass is added by way of the addition of weights, referenced 79, to the minor portion R2. Clearly, the distribution and volume of the hollow spaces 77, and the mass and distribution of the weights 79, will depend on the precise size and density of the rotor in any given application of the machine, and is thus not discussed herein in detail.
It will also be noted that typically the hollow spaces 77 are formed by manufacturing the rotor in two separate portions P1 and P2, which are then bonded together along a common interface i by use of a suitable cement, such any of the BONCERAM™ series of ceramic adhesives, manufactured by Hottec Inc., of 1 Terminal Way, Norwich, Conn. 06360, USA.
Furthermore, as seen in
As described hereinbelow, the rotors are preferably formed of ceramic materials which have a very low thermal expansion coefficient, and very highly insulation properties.
Furthermore, while the weights 79 are preferably made of a suitable heavy metal, the are made from a material which is selected for its low thermal expansion coefficient. Furthermore, as will be appreciated from an understanding of the operation of the machine as an ICE, the rotor portion R2 the rotor the weights are located is on the ‘cool’ side of the rotor, such that they are subjected to a minimum amount of heating. The positioning of the weights away from the exterior edge of the rotor, coupled with the good thermal insulation properties of the ceramic material from which the rotor is formed, further serves to reduce a chance of any damaging thermal expansion of the weights.
Referring now briefly to
As described above, the rotors of the present invention, while having a generally rounded shape, are not circular. It will be appreciated that, while the precise shape and dimensions may change from application to application, the construction of the rotors must be very precise, and must be shaped so as to correctly interact both with each other and with the cylindrical interior side walls of the working chamber, so as to provide a desired compression of working fluids, and momentary formation of combustion chambers, as they rotate at high speed.
In general, and as seen in
The construction of the rotors is described below in conjunction with
In general terms, it may be said that each rotor includes a pair of parallel side surfaces; and a curved perimeter surface formed between the pair of parallel side surfaces, formed of a plurality of curved portions, each abutted by a pair of the curved portions, contiguous therewith and mutually tangential thereto.
More specifically, however, and referring to
The height of the rotor taken along an axis of symmetry bisecting the major and minor segments S1 and S2 equals D.
D=R1+R2, in which R1 is the radius of the major segment S1, and R2 is the radius of the minor segment S2.
Each of the arcs A1 of segment S1 and A2 of segment S2 subtends an angle α at axis P, such that the arcs define points J, K, L and M.
Point J, whose position varies in accordance with the magnitude of the angle α, is used to determine the origins of radii r and R (FIG. 7), which are used to plot the points defining the curves which connect between the arcs of the major and minor segments.
It will now be seen that the shape of the rotor can be determined as follows:
It will thus be appreciated that the compression ratio for any specific machine design will be predetermined in accordance with the angle α. Generally speaking, it is to be expected that a 4° change in this angle will result in a corresponding change of 3-4 units of compression ratio. It will further be noted, however, that such a change also causes a corresponding change in the length of the duration of the expansion phase.
It should be borne in mind, furthermore, that a further parameter affecting the compression ratio is the ratio of the major to minor axes R/r, wherein a reduction in R/r causes an increase in the compression ratio, whereas an increase therein causes a corresponding reduction in the compression ratio.
The inventor has found that the rotor of the present invention, when employed in a rotary machine generally as described herein, provides for compression ratios of up to 1:30 or more. This represents a further improvement over the cylindrical rotor of the applicant's U.S. Pat. No. 6,250,278.
Furthermore, notwithstanding the fact that the present rotor is non-cylindrical, it is nonetheless very close to cylindrical, and is built so as to observe the following rules:
Referring generally now to
More specifically, a selected liquid fuel, typically hydrocarbon, is supplied to combustion chambers C1 and C2 preferably by suitable fuel injectors, at one or more suitable locations in the working cavities. While various embodiments of the invention are shown and described hereinbelow in conjunction with
In the event that a gasoline type fuel is intended to be used, which requires a lower compression ration, for example, 1:10, it is preferred to inject it at a relatively more upstream location, referenced 40a, prior to substantial compression.
Referring now briefly to
In the event that a diesel type fuel is to be used, it is preferred to inject it at one or more relatively more downstream locations, referenced 40b and 40c, so that the fuel is injected into an air volume that is already compressed.
As rapid ignition is required, due to the very short working stroke, the fuel injector is a suitable high speed, very high pressure injector. One type of injector that may be used is that manufactured by Orbital Engine Company (Australia) Pty. Limited, of Balcatta, Australia, and similar to that described in the article entitled CAN THE TWO-STROKE MAKE IT THIS TIME?, published on pages 74-76 of the February 1987 publication of POPULAR SCIENCE.
Repeated combustion at the same portions of the rotors and housing, in substantially insulated chambers, causes a significant increase in temperature during operation of the engine in the chambers, to temperatures well above the ignition temperatures of fuels used therein. Therefore, the engine components, including rotors A and B, housings 30 and 32, bearing plates 34 and 36 (FIG. 1), and partition wall 38 (FIG. 1), are built from material that are capable of withstanding very high temperatures.
By way of example, the rotors and housing may be formed of ceramics such as direct sintered silicon carbide, of which the maximum use temperature is 1650° C., and reaction bonded silicon nitride, having a maximum use temperature of 1650° C.
However, the mere fact that the fuel air mixture ignites so as to provide heat, and the rotor associated therewith is seen to have worked, i.e. by rotation, this necessarily is accompanied by a decrease in temperature. Moreover, the supply of cool air with fuel, and similarly, the exit of exhaust gases from the engine, together with the accompanying entry of cool air into the engine, moderates the temperature increase to a point at which thermal equilibrium is reached. The point of thermal equilibrium is, however, higher than the combustion temperature of fuels used in conjunction with the engine of the invention.
By way of example, as known by persons skilled in the art, diesel fuel normally requires an air compression ratio of at least 1:16 in order to reach an ignition temperature. In the present invention however, even though the compression ratio may be well below 1:16, the elevated temperature of the surfaces after initial operation of the engine, is, as described above, sufficient to maintain ignition during successive combustion cycles, without requiring either sparking or increased air compression.
It is a feature of the present invention that, in order to enable operation of the machine, when used as an ICE, at high temperatures, and maximum power output of the machine, the following conditions are met:
It will be appreciated that, construction of the machine in accordance with the above conditions, is facilitated by forming the rotor and rotor housings of a suitable ceramic material, which may be, by way of non-limiting example, silicon nitride or silicon carbide, as mentioned above. The rotors and housings must, of course, also be formed so as to have mechanical strength adequate for their intended use.
The use of a ceramic material is itself facilitated by the fact that none of the moving parts touch, as well as the fact that the bores are completely cylindrical, and rotors A and B are mounted therein so as to be parallel thereto, and normal to rotation axes 42′ and 44′. As described above in conjunction with
Furthermore, as described in detail above in conjunction with
It will be appreciated that the tolerances between the various machine portions can be reduced in accordance with the accuracy of their manufacture, and this, in turn, improves the performance of the machine.
The use of ceramics for construction of the rotors, rotor housings 30 and 32, bearing plates 34 and 36, and partition plate 38, enables high operating temperatures to be sustained, thereby providing a large temperature difference between the interior and exterior of the engine, so as to maximize its efficiency, in accordance with the well known Carnot Law. The absence of lubrication in the combustion chambers also leads to a reduction in emissions caused by burning of lubricating fluids.
It will be appreciated by persons skilled in the art that, as opposed to reciprocating engines in which the combustion cavities have a low ratio of surface area to volume, in the present invention, in which the combustion cavities have a high ratio of surface area to volume, if either the rotors or the rotor housings were to be made from a heat conductive material, such as metal, there would be a very large and rapid loss of thermal energy, and the present invention would not be able to function as an internal combustion engine.
It is an important feature of the invention that, in order to maximize machine performance, frictional loss is reduced to a minimum. Accordingly, while rotors A and B may appear to be touching in certain positions, and the rotors may also appear to be touching inner surfaces of the rotor housings, as seen in the magnified view of
Each rotor A and B in each pair or rotors, is mounted, as seen clearly in
Referring now once again briefly to
It should be noted that, for the sake of brevity, housing 32 only is described herein in detail, and that housing 30 has a substantially identical construction thereto.
As seen in
Shutter elements 85 (
During a working fluid “filling stage,” pressures higher than atmospheric pressure are developed within housings 30 and 32, due to the large volume of air required to be taken in, during a very short period of time. Accordingly, the air intake is preferably assisted by means of an external pressure source, such as a supercharger or the like, for example, as shown and described hereinbelow in conjunction with engine 1010 (FIGS. 24 and 26).
Referring now briefly to
Referring briefly to
It will be appreciated that the terms “upper” and “lower” merely correspond to the orientation of apparatus in the drawings, and have no significance therebeyond.
There are also provided upper and lower electrode pairs, respectively referenced 108 and 110, seen in
Prior to the description below of a complete working cycle of the machine 10 as an ICE, operation thereof with regard to a combustion force generated, is described, in conjunction with
Shown in
In the case of use of a gasoline-type liquid fuel, injection occurs closer to the start of compression, via more upstream location 40a (FIG. 10A), and is thus not seen in the present drawing.
At this time, expansion of the combustion gases resulting from the ignition has just started, and the combustion chamber is bounded by portions of non-joining wall 78, as well as a relatively short portion a of rotor A, and a relatively long portion b of rotor B. For the duration of combustion in combustion chamber C2, rotor B is defined as the leading rotor, while rotor A is defined as the trailing rotor. As long as expansion of the combustion gases continues, there is a net rotational force applied to leading rotor B, causing rotation in a direction illustrated in
As rotors A and B continue to rotate, the combustion gases expand and combustion chamber C2 also increases in size accordingly, as seen in FIG. 11B.
This continues substantially until leading rotor B passes the position seen in
The above example relates to the portion of the power cycle in which rotor B is the leading rotor and rotor A is the trailing rotor. In the portion of the power cycle in which combustion chamber C1 is employed, however, rotor A is the leading rotor, and rotor B is the trailing rotor.
For sake of clarity, the following operating positions are described below in conjunction with
It will be appreciated that, where used, the terms “upper”, “lower”, “raised”, and “lowered” are orientations used only to indicate portions or positions as they appear in the drawings, and that these portions or positions do not necessarily take on these orientations in the machine when in use.
Referring now initially to
In the event that a gasoline-type liquid fuel is being used, the volume of air will in fact be a volume of a compressed air-fuel mixture, due to an injection of fuel via fuel injection location 40a.
At this stage, air is supplied to the working chamber via lower intake port 86a.
In the event that a diesel-type fuel is used, it is supplied to combustion chamber C1, via either or both upper fuel injectors 40b or 40c.
The fuel-air mixture in combustion chamber C1 is ignited, in the present embodiment, by operation of upper electrode pair 108, causing a rotation of rotors A and B in a clockwise direction, towards the position seen in
At this stage, upper air intake port 86b becomes uncovered by trailing rotor B, thereby to permit an intake of air which is used not only for the flushing of exhaust gases from the working chamber, but also as the air component in lower combustion chamber C2 (FIG. 11B), during the next power cycle.
Referring now also to
Referring now to
Rotor B, having rotated through an angular displacement identical to that of rotor A so as to have uncovered upper air inlet port 86b, starts to move away from apex 78′ of upper partition 78. Once this has happened, a “scavenging” gas flow path is provided so as to extend from upper air inlet port 86b, along the upper side surfaces 102 and 100 of respective bores 76 and 74, as indicated by arrows 105, exhaust inlet bores 94, bore 92, and upper exhaust outlet port 88a. The provision of this flow path causes the hot waste gases to be flushed out of the cavity, and these may then be released into the atmosphere as via exhaust outlet port 31 (FIG. 1). Alternatively, however, due to the residual heat energy and pressure of the waste gases, they may be usefully recycled.
Subsequently, in the event that a diesel-type fuel is used, it is supplied to lower combustion chamber C2 (FIG. 11A), via either or both lower fuel injectors 40b or 40c.
The fuel-air mixture in the combustion chamber C2 is ignited by operation of lower electrode pair 110, causing a rotation of rotors A and B in a clockwise direction, towards the position seen in
At this stage, as seen in
Referring now to
It will be noted that the positioning of the external air intake port 586 and exhaust port 588 are such that the main bores 592 and inlet bores 594 of the rotors serve for air intake into the working chambers, and exhaust gases are exhausted directly from the combustion chambers to the exhaust ports 588, thereby more readily exhausting exhaust gases than is provided with the configuration shown and described above in conjunction with
It is particularly noteworthy that, in addition to the air intake ports 586, there may be provided optional compressed air intake ports 586′.
Referring now also to
As the rotors rotate in the direction indicated by arrows 515, compressed air from an external source (not shown) starts to enter the working chamber via air intake port 586 and inlet bores 594, as main bore 592 moves into registration with first compartment 561. The air thus entering the working chamber is clean air, and thus serves to scavenge or flush the working chamber of all burnt gases, prior to the start of compression therein. Subsequently, as main bore 592 is brought into registration with the second, middle compartment 563, fuel injector 540 is operated so as to inject fuel into the external air intake, thereby causing mixing of the fuel as it enters the working chamber, prior to compression and ignition, as by spark electrodes 508.
Immediately after the injection of fuel as described, and before the working chamber is sealed for the onset of compression, the rotor is further rotated such that main bore 592 is brought into registration with the third compartment 565, so to permit a further intake of air. It will be appreciated that this flushes through any remaining fuel in the main bore 592 and inlet, bores 594, and thus ensures that no fuel remains outside of the combustion chamber in formation as the rotors rotate.
Referring now to
In order to employ the external working gas in this way, the operation of machine 10 is reversed, such that the ports used as exhaust ports 88a and 88b in the embodiment of
In operation, as the high pressure working gas is supplied to intake ports 288a and 288b, as, for example, in the position illustrated in
Referring now to
In accordance with one embodiment of the invention, the compressor may be incorporated into a machine system, generally as described in applicant's co-pending U.S. Ser. No. 09/099,521. Alternatively, however, the compressor may be used as a stand-alone machine, and is thus provided with appropriate exit valving (not shown) so as to enable accumulation of a gas under pressure, as known in the art.
In brief, the power cycle for this embodiment of the invention is shown in the sequence of
Referring now to
It will be noted that components of compressor 710 having counterpart components in
Referring now generally to
By way of introduction, diesel engines, per se, are well known, as is the fact that the air that is used to create the “fuel-air” mixture needed to operate a diesel engine is compressed in the engine in the absence of fuel. This contrasts with gasoline engines, wherein the air is compressed together with the fuel.
The reason for the pre-compression of the air prior to the introduction of fuel, in the case of the diesel engine, is that this enables a much greater compression of the air, which greatly increases in temperature of the compressed air. Subsequently, the injection of fuel into the space containing the hot compressed air, leads to evaporation of the fuel upon contact with the air and ignition, thereby to produce the gases which drive the engine.
The rotary machine of the present invention lends itself to use as a diesel engine, primarily due to the high compression ration that is achieved, as described herein. Furthermore, as known, in a piston engine, compression of the air, injection of the fuel, and ignition of the fuel-air mixture are all performed at the same location, namely, in each cylinder, so as to drive the related position.
In the rotary engine of the present invention, however, the portions of the engine in which air is compressed, are located differently from those portions where fuel is injected and combustion occur. It will also be borne in mind that, as described above, the rotary mechanism of the present invention is constructed of ceramic materials having special isolative properties which, inter alia, prevent the transfer of heat from one place to another within the engine. This creates a relatively cold spot in part of the air collection and compression space. Use of this feature will be discussed below.
As seen in the drawings, engine 410 has identical upper and lower sides, referenced generally I and II, which operate alternately. Engine 410 is seen to have rotors A and B which rotate about respective axes 442′ and 444′, in a manner similar to that described herein. As with other embodiments of the invention, rotors A and B rotate in a clockwise direction, although if desired, the engine could be modified so as to allow for counter-clockwise rotation of the rotors.
Engine 410 has formed therein a pair of working fluid inlet ports 486a and 486b, via which air may enter into working chambers 474 and 476, respectively. Each of inlet ports 486a and 486b has associated therewith means, such as the herein-described shutter elements 85 (FIG. 1), such that air may be allowed to enter through inlet ports 487, but may not exit therethrough. When the rotors are in the positions shown in
As the rotors continue to rotate, as shown in
The ratio between these volumes may be as much as 30:1 or more, causing a corresponding compression of the air within the compression chamber. This causes a significant increase in the temperature of the air within the space 476′.
At the position seen in
Expansion of the exhaust gases as seen in
As seen in the drawing, during compression of the air until the extent seen at 476′ (FIG. 21B), exhaust port 488a is blocked off by rotor A. As rotor A rotates however, under the effect of combustion, as seen in
It will be appreciated that as the engine performs work on both sides, generally shown as I and II in the drawings, each stroke, while producing substantial energy, results in a relatively angular motion of the rotors, when compared to a piston engine. Accordingly, excess energy results, unused by the engine rotors. This excess energy is preferably exploited by provision of a turbo or other external energy recovery device.
It should be noted that the temperature of the exhaust gases remains high. This is especially true prior to their being exhausted from the engine housing 430 which, as described above, is made of insulative ceramic material which can withstand very high temperatures. Due to the insulative properties of the engine components and their inherent ability to withstand high temperatures, little cooling, if any, is required. As it is not possible to utilize all the excess heat energy, it is preferred to exploit this excess energy too, by provision of a turbo or other external energy recovery device.
As seen in
Accordingly, the removal of the burnt gas deposits, known as scavenging, is accomplished by admitting clean air into the passage via inlet port 486b, which, as indicated by the arrows, passes through the passage and exits via exhaust port 488a. Other methods of scavenging are discussed herein on conjunction with other embodiments of the invention.
It should be noted that, while clean air should enter engine 410 automatically via inlet port 486b due to the reduction in pressure created by rotation of the rotors, it may be desirable to employ additional means to prevent escape of air once scavenging has finished, which could occur due to the exhaust port 488a still being uncovered by rotor A. The solution to this problem lies in the provision and operation of a shutter element (not shown), and which is discussed in detail in conjunction with
With additional reference to
In order to appreciate the significance of the location of the fuel injection ports, it is important to note the following factors, all of which play a part in the operation of engine 410 as a diesel engine. These factors include the following, which are characteristic of engine 410 of the present invention:
It will be appreciated by persons skilled in the art that the ideal situation would be to inject fuel into the air prior to compression, so as to facilitate maximum mixing of the air and fuel during the compression phase, thereby resulting in an increase in the time available for evaporation of the fuel droplets, and thus to maximize the amount of fuel burned during combustion.
Therefore, it is important, in the specific design of the diesel engine of the present invention, to predetermine its performance while taking into account the following factors: compression ratio, injection location, and rotational speed.
In accordance with these factors, two alternative variations are taken into account in the present invention, namely, either reducing the compression ratio, thereby to prevent premature ignition due to elevated temperatures produced by overly compressed air, or, as an alternative, to provide injection as far as possible downstream, while nonetheless ensuring satisfactory mixing with the air. It will also be appreciated that the injection timing is also an important factor. Clearly, and as stated above, the high speed of rotation which results in a very short combustion phase and a reduced chance of combustion in the compression chamber occurring as a result of premature ignition, mitigates the need to reduce the compression ratio, on the one hand, and the need to provide injection in a relatively downstream location, on the other hand.
Of the four alternative locations indicated in
As an alternative, the engine may be constructed so as to provide a lower compression ratio, such as 1:14 or less, thereby avoiding premature ignition. In order to assist in ignition, there may be provided hot points such as glow plugs or permanent spark plugs, as shown at 408.
Referring now to
As seen in
Rotors B and A are shown in
As rotation continues, and rotors B and A are oriented such that the gas pressure in space 376 is greatly reduced, as shown in
Referring now to
Many of the components and portions of machine 1010 are similar to those shown and described hereinabove in conjunction with machine 10 of
Furthermore, for the purpose of clarity, all portions and components of machine 1010 which are described herein with regard to
Returning now to
The various static portions of the machine 1010, are preferably mounted together as shown and described herein, by use of a plurality of tie rods, referenced 1012a, which extend through suitable openings referenced 1012b formed in the edges of the static machine portions, as seen in
Body 1012 is subdivided, in the present example, into two rotor units, referenced generally R1 and R2. Each of rotor units R1 and R2 includes a rotor housing 1030, shown in plan view in
As seen, located between housings 1030 is a pair of deflector plates 1038′ and 1038″, which are separated by a conducting plate 1039. The deflector plates seen in
Referring now also to
Mounted adjacent to air intake ports 1027, on respective drive shafts 1042 and 1044, are impellers 1027′. Impellers 1027′ are provided so as to take advantage of the high speed of rotation of the drive shafts 1042 and 1044, so as to slightly raise the pressure of the clean air intake into the engine.
After entering the engine, air is directed to the working chambers of the engine, via a pair of inlet conduits 1029a, of which only a single one is seen in FIG. 24. Exhaust gases are expelled from the working chambers along a path shown by arrows 1029′, via exhaust conduits 1029b, of which only a single one is seen in FIG. 24. The inlet and outlet conduits 1029a and 1029b, are formed by suitable openings formed in bearing plate 1036, rotor housings 1030, deflector plates 1038 and conducting plate 1039. The openings formed in rotor housings 1030, and deflector plates 1038, are denoted with the reference numerals 1029a or 1029b, as appropriate. The corresponding openings in conducting plate 1039 for inlet and outlet conduits 1029a and 1029b are denoted by reference numerals 1029c and 1029d, respectively.
When machine 1010 is constructed as an ICE, the exhaust gases are waste gases resulting from combustion of an air-fuel mixture. When machine 1010 is constructed as a motor or compressor, however, the outlet conduits 1029b simply serve to permit egress of the working fluid from the machine.
As will be appreciated from FIG. 24 and
In a clean air filling phase however, such as seen in the working chamber of the upper portion I of
It will be appreciated that the inlet ports 1086 and exhaust ports 1088 extend through lower deflector plate 1038″ at a slant, thereby to properly communicate with portions of the inlet and outlet conduits 1029a and 1029b formed in conducting plate 1039, as seen in
Referring now briefly to
Referring now briefly to
It will be appreciated by persons skilled in the art that the scope of the present invention is not limited by what has been shown and described hereinabove. Rather the scope of the present invention is limited solely by the claims, which follow.
The present application is a 35 USC 371 national phase application from and claims priority to International Application PCT/IL/02/00505, filed Jun. 25, 2002, established under PCT Article 21(2), in English. PCT/IL/02/00505 claims priority to and is a continuation in part of U.S. Ser. No. 09/887,060, entitled Improved Rotary Machine, filed on Jun. 25, 2001, now U.S. Pat. No. 6,604,503 to Mekler, and now entitled Rotary Machine. The contents of both PCT/lL/02/00505 and U.S. Ser. No. 09/887,060 are incorporated herein, by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IL02/00505 | 6/25/2002 | WO | 00 | 12/23/2003 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO03/00103 | 1/3/2003 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 1656538 | Smith | Jan 1928 | A |
| 1771863 | Rudolf | Jul 1930 | A |
| 1837714 | Jaworowski | Dec 1931 | A |
| 2845909 | Pitkanen | Aug 1958 | A |
| 3078807 | Thompson | Feb 1963 | A |
| 3726617 | Daido | Apr 1973 | A |
| 4152100 | Poole et al. | May 1979 | A |
| 4666383 | Mendler, III | May 1987 | A |
| 4968234 | Densch | Nov 1990 | A |
| 5152683 | Signorelli | Oct 1992 | A |
| 5341782 | McCall et al. | Aug 1994 | A |
| 5898256 | Ide et al. | Apr 1999 | A |
| 6250278 | Mekler | Jun 2001 | B1 |
| 6298821 | Bolonkin | Oct 2001 | B1 |
| 6604503 | Mekler | Aug 2003 | B2 |
| Number | Date | Country |
|---|---|---|
| 492804 | Mar 1930 | DE |
| 3241253 | May 1984 | DE |
| 735 814 | Nov 1932 | FR |
| 2 690 201 | Oct 1993 | FR |
| Number | Date | Country | |
|---|---|---|---|
| 20040182357 A1 | Sep 2004 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09887060 | Jun 2001 | US |
| Child | 10481598 | US |
