The embodiments described herein below relate to Rotary Combustion Engines (RCE) such as a Wankel engines, and in particular to the reversible deactivation of at least one rotor of such an engine.
It is an object of the embodiments of the present invention to provide a Rotary Combustion Engine (RCE) suitable for the deactivation of at least one rotor out of a plurality of rotors. The RCE may comprise at least a first shaft portion and a second shaft portion, thus at least two shaft portions which are disposed in straight coextensive longitudinal axial alignment. Each one shaft portion is configured to support at least one rotor. The first shaft portion and the second shaft portion are separated apart by a gap. A shaft coupling mechanism is operable to couple the first shaft portion in engagement with the second shaft portion for rotation together. Furthermore, the shaft coupling mechanism is operable to disengage the first shaft portion from the second shaft portion, and thereby, to deactivate the rotation of at least one rotor.
It is a further object of the embodiments of the present invention to provide a method for reversibly deactivating at least one rotor of a Rotary Combustion Engine (RCE) having a plurality of rotors. The method comprises an RCE which has at least a first shaft portion and a second shaft portion, thus at least two shaft portions. Those at least two shaft portions are disposed in straight mutual coextensive longitudinal axial alignment. Each one shaft portion operates at least one rotor. Moreover, the first shaft portion is separated apart from the second shaft portion by a gap. There is also provided a shaft coupling mechanism for coupling the first shaft portion and the second shaft portion into simultaneous synchronous rotation and indexed angle. The shaft coupling mechanism may also separate and disengage the first shaft portion from the second shaft portion to thereby deactivate the operation of at least one rotor out of the plurality of rotors.
The difficulties encountered in the attempts to deactivate reciprocating pistons of internal combustion engines (ICE) are well known from the days of the Cadillac V8-6-4 engine. With an RCE (Rotary Combustion Engine), one may consider the problem of deactivation one or more rotating rotor(s) to be similar to the problem of deactivation of reciprocating pistons. The problem is thus how to deactivate a rotating rotor of an RCE, or rotary combustion engine.
Solution of the Problem
Contrary to the crankshafts of reciprocating piston internal combustion engines (ICE) with cranks and throw pins, the shaft which supports the rotor(s) of an RCE, such as a Wankel engine for example, features a shaft which extends in straight coextensive longitudinal axial alignment. Therefore, to deactivate a rotor, it suffices to disengage from rotation that portion of the shaft which supports the rotor(s) to be deactivated.
The solution of the problem is achieved by dividing the shaft of an RCE into two shaft portions that are separated apart by a gap. Upon separation of the rotating shaft of a running RCE by the gap, the first shaft portion, or rotation output portion, will continue to rotate but the second shaft portion, now separated apart therefrom by the gap, will come to standstill, and so will the rotor(s) supported by the second shaft portion.
To reunite two shaft portions for rotating together in common rotation, use may be made of a shaft coupling mechanism SCM to form a united shaft which will activate the rotor(s) previously deactivated by the separation of the shaft into two shaft portions. One or more coupling element(s) of the coupling mechanism SCM will provide not only rotational speed synchronization but also phase synchronization for preservation of the required mutual angular relationship existing between rotors. Such requirement is necessary for smooth operation of the RCE and for mitigating vibrations.
A shaft coupling mechanism SCM, configured to reversibly operate the disengagement of a first shaft portion from a second shaft portion, will disengage the second shaft portion and the thereby deactivate the supported rotor(s). Operation of the shaft coupling mechanism SCM to couple back the first shaft portion together with the second shaft portion will return the deactivated rotor(s) of the RCE into operation.
In certain situations, such as low load, the deactivation of a rotor allows the RCE to operate at or closer to engine optimal operational conditions, with less pollution damage to the environment, and with reduced fuel consumption. For example, when the RCE runs at idle speed or at light or partial load, it may be more economical to deactivate one or a portion of the available rotors. Evidently, a deactivated rotor is not fed with fuel/gas and ignition to that rotor may be discontinued.
Exemplary embodiments are illustrated in referenced figures. It is intended that the embodiments and figures disclosed herein are to be considered illustrative, rather than restrictive. The embodiments of the invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read in association with the accompanying figures, in which:
For the sake of clarity and simplicity of the drawings, the Figs. are rendered schematically, for example, in the manner in which
In the description hereinbelow, it may be assumed that when the second distal shaft portion SH2 is disengaged, it is the proximal first shaft portion SH1 that continues to provide rotative power output. Reference to two shaft portions SH1 and SH2 and to two rotors R1 and R2 is used for the sake of simplicity of description and of the drawings. Proximal and distal directions are indicated in the Figs. by arrows marked as, respectively, proximal and distal. A shaft SHFT as shown in
To rotate both the first and the second shaft portions, respectively SH1 and SH2, in synchronous rotation and in angular indexed relation, there is provided a shaft coupling mechanism SCM. In principle, a shaft coupling mechanism SCM for crossing or bridging the gap G may include a geared or splined bushing, having a slide dog interior SDINT and exterior EXT, configured to engage the first shaft portion SH1 together with the second shaft portion SH2 for rotation in common.
The shaft coupling mechanism SCM, which is configured as a slide dog SD in
A proximal translation of the slide dog SD across the gap G and onto the proximal first extremity 1EX of the first shaft portion SH1 allows the rotation in common of both engaged shaft portions BSHP.
A splined shaft with male splines MS is defined as a shaft having a number of equally spaced grooves cut on the exterior surface of the shaft so as to form a series of projecting keys and fitting into an internally grooved cylindrical member which is a female splined shaft having recessed splines FS. Splined shafts do transfer torque and maintain angular correspondence. A male master spline MMSTR wider than the other male splines MS and configured to engage a matching female master spline FMST may be provided to maintain a predetermined relative angular orientation between rotors R.
The deactivation of one or more rotors R may be advantageous to run the RCE 100 at optimal operational condition for example with a vehicle, not shown in the Figs., at standstill for a lengthy period of time while the RCE 100 is running just for the sole purpose to charge a battery. Evidently, the engine control unit ECU of the RCE 100 may automatically detect that say, the output provided by a single rotor R suffices to drive a generator for recharging a battery.
Upon command of the user U, or of the engine control unit ECU, an actuator ACT, shown in block 107, may impart a motion via one or more of a motion transfer mechanism MTM of block 109, to the shaft coupling mechanism SCM shown in block 111. Such a motion may include for example, a translation of a slide dog SD and/or of another element of the shaft coupling mechanism SCM. The actuator is thus coupled to controllably operate the shaft coupling mechanism SCM. The actuator ACT may be selected as an apparatus that is mechanic, pneumatic, hydraulic or electric, or as a combination of such apparatus, like for example, an electro-mechanical device. When it is the user U who is in command, he himself may exert, by hand or by foot, the force necessary to operate the shaft coupling mechanism SCM, whereby the actuator ACT becomes superfluous.
Alternatively, the user U may operate a device, not shown, to set the actuator ACT into operation. Once the actuator ACT performed the requested motion, it is the task of the motion transfer mechanism MTM, shown in block 109, to drive the shaft coupling mechanism SCM into desired position, either in a shaft portions SH(s) engaged position ENG, shown in block 113, by which a rotor(s) R enters the “ACTIVATED” state, or in a portions SH(s) disengaged position DIS, shown in block 115, by which a rotor R or rotors R(s) reaches the “DEACTIVATED” state.
For the sake of ease of description, the exemplary embodiments described hereinabove referred to an RCE 100 having two shaft portions SH1 and SH2, wherein each one shaft portion SH supports but one rotor R. However, even though not shown in the Figs., an RCE 100 may operate with more than two shaft portions SHs, wherein each one shaft portion supports more than one rotor R, and each one shaft portion may even support a same or a different number of rotors R. If desired, the rotors R supported by different shaft portions SH may have a same or a different volume.
The RCE 100 may operate a plurality of n shaft portions SH, wherein each one shaft portion SH supports a plurality of m rotors R. In general, an RCE 100 may have n shaft portions SH[SH1, SH2, SH3, . . . SHn], wherein each one shaft portion SH supports m rotors R[R1, R2, R3 . . . Rm]. Evidently, n−1 shaft coupling mechanisms SCM coupling the n shaft portions SH are sufficient to disengage (n−1) shaft portions SH2 to SHn from the first shaft portion SH1, and these (n−1) disengaged shaft portions will then deactivate a maximum of (n−1) times m rotors Rs, or m*(n−1) rotors Rs that the shaft portions SH2 to SHn support.
The distal and the proximal first and second facing extremities 1EX and 2EX of respectively, the first and the second shaft portions SH1 and SH2, may each one have a facing hollowed out portion HOL, indicated as HOL and HOL2. If desired, the entire length of the first and the second shaft portions SH1 and SH2 may have a hollowed out tubular interior INT, however at some cost to rigidity.
In
To engage both shaft portions BSHP, thus the first and the second shaft portions respectively SH1 and SH2, for rotation together in common, the slide dog SD having male splines MS is translated proximally along the female splines FS2 of the second shaft portion SH2 over and across the gap G. The slide dog SD which bridges the gap G is driven further proximally to engage the female splines FS1 of the first shaft portion SH1. Thereby, both shaft portions BSHP now form one united rotating shaft which rotates the rotor(s) R(s) supported by the first shaft portion SH1 and the second shaft portion SH2.
The shaft coupling mechanism SCM, here the slide dog SD, may be translated via a motion transfer member(s) TRNSF operated by an actuator ACT.
In
The distal portion DP of the first shaft portion SH1 supports a female friction cone FFC for engagement with the thereto opposite male conical surface MCS. In the slide dog SD, a spring loaded ball SPLB is retained in a bore BR, here a radial blind bore, for the spring loaded ball SPLB to engage a circumferential channel CCH cut in the male slidable friction member MSFM. Thereby, the spring loaded ball SPLB retains the male slidable friction member MSFM in desired position relative to the slide dog SD. It is noted that indexing mechanisms other than a spring loaded ball SPLB may be used to hold the male slidable friction member MSFM in desired position. However, proximal translation of the slide dog SD brings the male slidable friction member MSFM in contact with the female friction cone FFC. Further proximal translation of the slide dog SD urges the distal mail splines DMS against the male slidable friction member MSFM may push the spring loaded ball SPLB out of the circumferential channel CCH and permit some additional distal translation of the slide dog SD relative to the first shaft portion SH1. Evidently, mechanisms different from a spring loaded ball SPLB retained in a bore BR may be used to keep the male slidable friction member MSFM in desired position relative to the slide dog SD.
As described hereinbelow with reference to
To disengage the second shaft portion SH2 from engaged rotation with the first shaft portion SH1, the motion transfer rod TRRD, which is fixedly coupled to the slide dog SD, is translated distally. Thereby, the first proximal male splines PMS are retrieved out of the female splines FS1 and contact is broken between the female friction cone FFC and the male conical surface MCS. Further distal translation of the slide dog SD will cause the distal male splines DMS to return the male slidable friction member MSFM in position over the spring loaded ball SPLB.
The motion transfer rod TRRD may be translated, for example, by action thereon of a lever LVR. Such a lever LVR is but an example of a principle of embodiment of an actuator ACT since various other motion delivery actuators ACT may be used to translate the motion transfer rod TRRD via a motion transfer mechanism MTM, shown in
It is noted that
The exemplary embodiment shown in
The slide dog SD has male splines MS which engage female splines FS of the second shaft portion SH2. Hence, when the teeth TH1 and the teeth THSD of the slide dog SD are engaged, torque is transferred from the first shaft portion SH1 via the slide dog SD to the second shaft portion SH2 to achieve rotation speed synchronization and torque transfer.
The distal portion SDD of the slide dog SD is operative as a motion transfer rod TRRD which is coupled to a lever LVR via a support ring SPPRG having a circumferential groove GR. Pivotal displacement of the lever LVR about the stationary pivot PVT which is affixed to a stationary item STI of the RCE 100, may thus translate the slide dog SD into proximal or distal direction. For engagement of both shaft portions BSHP, the lever LVR may be pivotally operated to drive the teeth THSD of the slide dog SD proximally into the teeth TH1 of the first shaft portion SH1. To prevent an accidental disengagement of the sets of teeth TH1 and THSD, pressure exerting resilient element(s) RLN, such as pressure springs for example, may be provided, for the teeth THSD to apply pressure force onto the teeth TH1. The resilient element(s) RLN apply force on the distal portion SDD of the slide dog SD and are supported by a stationary portion or stationary item STI of the RCE 100, and if desired, may be journalled by at least one bearing BRG. However, to prevent the application of axial forces onto the first shaft portion SH1, there is provided a force balancing rod FBR which is fixedly coupled proximally to the first shaft portion SH1.
To facilitate engagement of the first rotating shaft portion SH1 with the at standstill second shaft portion SH2 of the of the embodiments described hereinabove, the teeth of the splines may be chamfered. As indicated in
At a proximal end thereof, the force balancing rod FBR is fixedly attached to the first shaft portion SH1, and at the distal end thereof, the force balancing rod FBR is fixedly attached to the stationary item STI of the RCE 100 to which the pivot PVT of the lever LVR is affixed. From the distal end side at the stationary item STI, the force balancing rod FBR extends to the first shaft portion SH1 through an interior INT of the tubular slide dog SD. If desired, the force balancing rod FBR may be supported by a ball bearing BRG at the distal end thereof.
The various embodiments described hereinabove may be implemented by conventional engine-building means, methods and materials, well known to those skilled in the art and do not require further details.
The operation of an RCE equipped with an embodiment of a reversible shaft disconnection or disengagement apparatus, such as described hereinabove, may be automatic or manual. The deactivation/reactivation of a rotor include but an ON/OFF command and needs not to be described.
There has thus been described a Rotary Combustion Engine (RCE) operating a plurality of rotors and including an apparatus suitable for the deactivation of at least one rotor out of the plurality of rotors. The RCE may comprise at least a first shaft portion and a second shaft portion, thus at least two lengthwise adjacent shaft portions which are disposed in straight coextensive longitudinal axial alignment to each other. Each one shaft portion is configured to support at least one rotor. The at least the first shaft portion and the second shaft portion are separated apart by a gap which is sufficient to prevent the transmission of rotation from one shaft portion to the other thereto adjacent shaft portion. A shaft coupling mechanism is operable to couple together the first shaft portion in engagement with the second shaft portion to operate rotation together of both shaft portions as if being a unitary solid one-piece shaft. Furthermore, the shaft coupling mechanism is operable to disengage the first shaft portion from the second shaft portion, thus to allow the gap to prevent rotation together of both the first shaft portion and the second shaft portion. Thereby, disengagement of the at least the first shaft portion and the second shaft portion causes one of both shaft portions to stop to rotate by not being driven anymore. In consequence, the disengaged and now stopped from rotation shaft portion thus deactivates the rotation of the at least one rotor which is supported thereby.
The engagement and the disengagement of the at least the first shaft portion and the second shaft portion by the shaft coupling mechanism may be controlled by either an automatic and independent engine control unit operating on the RCE or by a user who controls the operation of the RCE. Remote control is regarded as being equivalent to control by a user. An actuator or actuation mechanism may command the shaft coupling mechanism to engage together and disengage from each other of the at least the first shaft portion and the second shaft portion The force and the motion to operate the shaft coupling mechanism may be provided either physically by the user or by the actuator.
Each one of the at least the first shaft portion and the second shaft portion may have an exterior and either a local hollow out or a completely end to end hollow interior. There is thus formed a tube enhancing lubrication, as divulged by the Applicant in Israel Patent Application No. 241420 of Sep. 9, 2015. Actually, when in operation, lubricant flows through the hollow shaft or shaft portions and the RCE is filled with mist of lubricant. The shaft coupling mechanism is configured for bidirectional longitudinal translation in the hollow tubular interior or partial hollow out of the shaft portions.
The shaft coupling mechanism may be disposed for operation in one of the hollow interior or on an exterior of the at least the first shaft portion and the second shaft portion. For an RCE operating more than two shaft portions, there may be at least one shaft coupling mechanism operative in the interior of a shaft portion and at least one shaft coupling mechanism operative on the exterior of a shaft portion.
The shaft coupling mechanism may be selected as a slide dog which may be configured as a kind of bushing having male splines on an exterior surface thereof to accommodate translation in the interior of a shaft portion, or have female splines to accommodate translation on the exterior of a shaft portion, or be designed to have both male and female splines.
The first shaft portion and the second shaft portion may have a hollowed out interior which may be disposed at least along a portion of the first shaft portion and the second shaft portion, or may have a tubular hollow interior which is disposed along the entire length thereof. The shaft coupling mechanism may travel in longitudinal bidirectional translation along the portion or the entirety of the hollowed out interior.
The shaft coupling mechanism may also travel in longitudinal bidirectional translation along an exterior surface of the at least first shaft portion and second shaft portion on both the interior thereof and the exterior surfaces.
The actuator which operates the shaft coupling mechanism may be selected alone or in combination as at least one of a device which is mechanic, pneumatic, hydraulic, or electric.
The shaft coupling mechanism may engage the first shaft portion and the second shaft portion by crossing or bridging over the gap, for rotation in common when the RCE is at standstill, or is running at idle speed, or is running in operative condition. The shaft coupling mechanism may disengage the first shaft portion from the second shaft portion when the RCE is at standstill or is idling. Furthermore, the shaft coupling mechanism may engage the first shaft portion and the second shaft portion in synchronous rotation and at a predetermined indexing angle.
The activation and the deactivation of the at least one rotor may be commanded automatically by the engine control unit or be operated directly by the user. Activation and deactivation refer to respectively, an engaged state and a disengaged state of at least a first shaft portion and a second shaft portion. In the engaged state more than one rotor is operative, and in the disengaged state, at least one rotor is deactivated. Activation is to be understood as engaging, thus coupling together at least a first shaft portion and a second shaft portion for rotation in balanced, journalled, and well lubricated operation, in rotational speed synchronization and angular phase adjustment.
There may thus be implemented an RCE 100 having a plurality of n shaft portions wherein each one shaft portion out of the plurality of n shaft portions supports m rotors, and wherein the n shaft portions are coupled to n−1 shaft coupling mechanisms to deactivate a maximum of n−1 times m rotors.
In the description and claims of the present application, each of the verbs, “comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements or parts of the subject or subjects of the verb. The words “comprising” and “including” do not exclude other elements or steps, and the indefinite claims does not indicate that a combination of these measures cannot be used to advantage article “a” or “an” does not exclude a plurality.
Furthermore, while the present application or technology has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and non-restrictive; the technology is thus not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art and practicing the claimed technology, from a study of the drawings, the technology, and the appended Although the present embodiments have been described to a certain degree of particularity, it should be understood that various alterations and modifications could be made without departing from the scope of the invention as hereinafter claimed.
The embodiments described hereinabove may be implemented by use of materials and manufacturing techniques well known to those skilled in the art of RCE construction. Therefore, such embodiments are applicable to the RCE production industry.