WO2009022918A1

WO2009022918A1 - Advance-retard mechanism for axial piston machine and axial piston machine incorporating such

Info

Publication number: WO2009022918A1
Application number: PCT/NZ2008/000203
Authority: WO
Inventors: Noel Stephen Duke; Robert Gulliver Lynn
Original assignee: Duke Engines Limited
Priority date: 2007-08-10
Filing date: 2008-08-08
Publication date: 2009-02-19

Abstract

A Z-crank axial piston internal combustion engine that includes a cylinder cluster of at least two piston containing cylinders rigidly located with respect to each other. Each cylinder includes at least one working fluid transfer port. A crankshaft is rotatable relative to said cylinder cluster and carries an angled crank about which a recipricator can rotate. It is in mechanical connection with the pistons. A ported member is presented relative to which the cylinder cluster can rotate. The ported member can seal the at least one fluid transfer port of each cylinder yet offer, at intervals, their exposure to spark plug(s) and/or working fluid delivery and removal facilities. An indexing drive controls the relative rotation so that desired range of movement of the piston in each cylinder is timed between TDC and BDC during transfer port exposure. An indexing drive phase controller provides an advance retard facility for the engine.

Description

"ADVANCE-RETARD MECHANISM FOR AXIAL PISTON MACHINE AND AXIAL PISTON MACHINE INCORPORATING SUCH"

FIELD OF INVENTION

This invention relates to an axial piston machine that includes a mechanism for adjusting the timing of fluid porting. The axial piston machine may be, but is not limited to, an engine, fluid pump or motor.

In particular, though not solely, this invention relates to a mechanism for altering the exposure timing of fluid transfer ports to cylinders with respect to the reciprocating motion of the pistons within cylinders of an axial piston machine such as two Qt four-stroke axial piston internal combustion engine or pump. BACKGROUND

An axial piston machine is a machine in which a plurality of axially extending cylinders, together comprising the cylinder cluster, are arranged in a generally rotationally symmetrical layout around a central axis coincident with the rotational axis of a crankshaft. Each cylinder contains a reciprocating piston. The cylinders may be parallel or slightly inclined to the crankshaft axis.

There are a number of different mechanisms that can be used to drive the reciprocating motion of the pistons in their cylinders, two of the most common types being Swashplate drives or Z-Crank drives. While terminology can vary, a swashplate is in effect a cam surface attached to and rotating with the crankshaft that drives or is driven by the reciprocating linear motion of the pistons such as described in US Patent 4,516,536. Each piston has a bearing or bearings attached to it that slides or rolls over the surface of the swashplate cam surface. Each piston also has some form of linear bearing such as the side of the piston within its cylinder that accommodates and resists the lateral forces created by the action of the piston- driving bearings sliding or rolling on the inclined surface of the swashplate. The piston-swashplate bearings may generally have a sliding or rolling speed over the swashplate in the order of two times the peak piston speed. While swashplates are adequate for axial piston machines having relatively low piston speeds such as compressors and hydraulic pumps or motors, modern internal combustion engines commonly have much higher piston speeds and a swashplate high speed combustion engine may consequently have high inertial loads and high bearing sliding or rolling speeds that may make standard swashplate configurations less attractive for internal combustion engines. Z-Crank drives employ an intermediate body known variously as a Wobbleplate, Wabbler, Reciprocator or Spider that rotates on reciprocator bearings mounted on and for rotation about an inclined crank section of the crankshaft. The inclined crank section has an inclined crank axis that intersects with the crankshaft's rotational axis at an acute angle (also known as the "swash angle") at a point hereinafter referred to as "point X".

The reciprocator is restrained against rotation relative to the cylinder cluster. Rotation of the inclined crank by rotation of the crankshaft causes the reciprocator to nutate. As a result points on the body of the reciprocator in a plane passing through point X and perpendicular to the axis of the inclined crank section of the crankshaft move in a predominantly axial oscillatory motion parallel to the crankshaft axis, with motion in the plane perpendicular, to the crankshaft axis being of relatively small magnitude. Such points define the preferred location for engaging connection rods for the transmission of motion between a piston and the reciprocator.

The connection between the reciprocator and pistons can take many forms but generally connection rods having sufficient rotational degrees of freedom at either end are utilised. The reciprocator bearings typically operate at much lower sliding speeds than would the piston swashplate bearings of an equivalent Swashplate drive. As a consequence frictioήal losses will generally be reduced and higher operating speeds may be made possible.

Axial piston machines may have a number of potential advantages over other multi- cylinder piston machine configurations including: reductions in size and weight, simplified fluid porting, and the ability to achieve close to perfect balancing of the dynamic inertial forces.

An axial piston machine that has the cylinder cluster moving relative to an inlet/outlet ported valve head that is timed to match the desired timing of piston positioning for the operation of the machine as an internal combustion engine is described in US 6494171.

The rotationally symmetrical layout of the cylinders in a two-stroke or four-stroke axial piston engine or pump makes it possible to use a single common rotary valve porting mechanism in which an opening in each cylinder head passes in succession past every port in the rotary valve head. For a four-stroke axial piston engine the rotation of the cylinder cluster and the crankshaft with respect to the rotary valve is controlled by an indexing drive as is for example described in the patent specifications of US Patent 3,654,906 (Airas), US Patent 6,494,171 (Duke), both of which describe engines in which the rotary valve head is held stationary while both the crankshaft and cylinder cluster rotate either in the same direction with respect to the rotary valve head (co-rotating) or in opposite directions with respect to the cylinder head (counter-rotating). For both co-rotating and counter-rotating four-strokes the speed ratio required between crankshaft and cylinder cluster will generally be equal to the number of cylinders, with the torque transmitted through the indexing drive from the cylinder cluster to the crankshaft being a fraction of the total engine torque output.

Counter-rotating engines possess some advantages in that for a given rate of piston oscillation the rotational speed of the cylinder cluster is_. lower. This can reduce the centrifugal loadings, bearing friction and sliding speeds of the seals between the cylinders and the rotary valve head. Epicyclic gear sets offer a simple means of implementing such a counter-rotating indexing drive and have been described in both US Patent 3,654,906 (Airas) and US Patent 6,494,171 (Duke). The epicyclic gear sets for such counter rotating engines are made up of a sun gear mounted on the crankshaft engaging with a number of planet gears mounted on bearings on a planet carrier rigidly fixed to the rotary valve head that in turn engage with an annular gear mounted off of the cylinder cluster.

The performance of piston engines and pumps is very sensitive to the manner and efficiency with which fluids are transferred into and out of the cylinders. In conventional inline crankshaft mounted piston engines, large performance gains have been realised through implementation of various mechanisms for altering the points in the cycle of piston motion at which the fluid ports open and close (hereinafter referred to as the "port timing") in response to changes in engine speed and load. Even relatively small changes in port timing can have significant impacts on performance.

It is accordingly an object of this invention to provide an axial piston machine that includes a mechanism that allows the port timing of an axial piston machine to be adjusted while the machine is operating as well as while it is stationary or to at least offer the public a useful choice. BRIEF DESCRIPTION OF THE INVENTION

Accordingly in a first aspect the present invention consists in an axial piston internal combustion engine comprising; a cylinder cluster comprising of at least two cylinders rigidly located with respect to each other, each cylinder spaced relative to the other(s) and about a cylinder cluster axis, each said cylinder including at least one cylinder opening for fluid inlet and/or outlet to and/or from said cylinder, in each cylinder, a complementary piston to reciprocate along a reciprocating axis defined by its respective cylinder, a crankshaft rotatable relative to said cylinder cluster about a crankshaft axis that is coaxial with the cylinder cluster axis, said crankshaft carrying a crank that has a crank axis passing through said crankshaft axis at an angle, a reciprocator rotatably mounted by said crank to rotate about said crank axis and about said crank, said reciprocator operatively connecting said pistons with said crank such that the rotational motion of the crankshaft with respect to the cylinder cluster drives the reciprocal motion of the pistons within their respective cylinders or visa versa, and allows consistent and controlled reciprocating displacement of each piston within its respective cylinder between top dead centre (TDC) and bottom dead centre (BDC) a ported member presented to facilitate a sealing of said at least one cylinder opening of each cylinder, said ported member including ports being comprised of a selection of at least one fuel injection port and/or at least one fuel ignition port and/or at least one fluid inlet port and at least one fluid outlet port positioned to allow fluid communication via said at least one cylinder opening of a cylinder to be separately established, indexing drive to transmit rotation between said cylinder cluster and said crank shaft to, in use, rotate said cylinder cluster relative said ported member about said crankshaft axis at a rotational rate indexed to the rate of rotation of the crankshaft thereby operatively presenting said cylinder openings to some or each of said ports to allow their cyclic communication with each cylinder in turn, at instances corresponding to the desired positions in the cyclic reciprocating motion of a said piston in its respective cylinder between its TDC and BDC positioning, an indexing drive phase controller to allow controlled variation of the angular phasing between the cylinder cluster and the ported member and thereby vary the location for each piston in its range of motion between TDC and BDC at which each said cylinder opening comes into communication with a port of the ported member.

Preferably the angular phasing of the otherwise fixed ratio rotational indexing of the crankshaft and cylinder cluster rotation with respect to the ported member can be varied by an indexing drive positional adjuster that can adjust the indexing drive positional relationship relative said ported member.

Preferably said indexing drive operatively acts intermediate of said cylinder cluster and said crankshaft and comprises a crankshaft mounted sun gear to rotate with said crankshaft about the crankshaft axis and an annular gear operatively connected to said cylinder cluster to rotate with said cylinder cluster about said crankshaft axis, and at least one intermediate planetary gear operative between said sun gear and said annular gear, said at least one planetary gear mounted relative said ported member.

Preferably said at least one planetary gear is held in a fixed angular position relative said crankshaft axis relative to the ported member, save for any indexing drive phase controller effected angular positional variation thereof relative said crankshaft axis, to vary the angular phasing between the cylinder cluster and the ported member.

Preferably said phase controller includes a carrier (preferably a spider arm) mounted with an axis of rotation coaxial the crankshaft axis, said carrier mounting at least one planetary gear that can rotate about a planetary gear axis relative to said carrier and is operative intermediate of a crankshaft mounted sun gear and an annular gear operatively connected to said cylinder cluster, said carrier being controlled for rotation to vary the angular position of the planetary gear about said crankshaft axis relative to the ported member to thereby vary the phasing between said cylinder cluster and said ported member.

Preferably a positional adjuster is provided to adjust the angular position of the planetary gear relative said crankshaft axis with respect to the ported member.

Preferably the positional adjuster acts on the carrier and is actuable from remote of the engine.

Preferably there are at least 3 planetary gears operative intermediate of the sun gear and the annular gear.

Preferably the indexing phase controller is capable of said controlled variation while said engine is operating.

Preferably any said controlled variation is performed in response to an electronic engine control system to permit performance optimisation during engine operation.

Preferably timing of ignition or fuel injection can be altered appropriately by an electronic or mechanical control system to complement any changes in the angular phasing. Preferably said ported member is stationary and said cylinder cluster, crankshaft and reciprocator all move relative thereto.

Preferably said crankshaft rotates in the opposite direction to the cylinder cluster relative a fixed reference that is stationary to said ported member.

Preferably a rotation restraint mechanism is operative between said cylinder cluster and said reciprocator to ensure the rotational speed of the cylinder cluster and reciprocator relative the ported member is synchronous.

Preferably the phase controller allows, by changes to the angular phasing between the rotation of said crankshaft and said cylinder cluster with respect to said ported member , the alteration of the angular location of said ports of said ported member- about said crankshaft axis with respect to .the angular position of said cylinder cluster about said crankshaft axis at which said pistons reach TDC, thus allowing the timing of fluid port opening and closing events of the cylinder opening with respect to the reciprocating motion of their respective pistons to be advanced and retarded.

Preferably said engine is a Z-Crank engine, and preferably an internal combustion Z- Crank engine wherein the fluid used is a fuel and/or fuel/air mixture.

Preferably said cylinder defined reciprocating axis of each piston is parallel to the crankshaft axis.

Preferably said cylinder cluster includes three or more cylinders.

Preferably said indexing drive includes a planetary gear set that comprises a first planetary gear and a second planetary gear that rotationally constrained relative each other and are each presented for co-rotation about a common planetary gear axis said planetary gear set operative between a crankshaft mounted sun gear and an annular gear operatively connected to said cylinder cluster wherein said first planetary gear is engaged directly or indirectly to said sun gear and said second planetary gear is engaged directly or indirectly to said annular gear, wherein the gear tooth angle of one of said first planetary gear and second planetary gear is different to the other, and wherein said phase controller can effect a displacement of said planetary gear set along the planetary gear axis so as to vary the phasing between said cylinder cluster and said ported member.

Preferably a positional adjuster is provided to adjust the position of the planetary gear set along the planetary gear axis.

Preferably said first planetary gear is a helical cut gear. Preferably said first planetary gear and said sun gear are complementary helical cut gears and are in direct contact with each other.

Preferably said second planetary gear is square cut.

Preferably said second planetary gear is a helical cut gear and that is has a helix angle that is not parallel to the helix angle of the first planetary gear.

Preferably said indexing drive includes a planetary gear set that comprises a first planetary gear and a second planetary gear that are each rotationally constrained relative each other and are presented for co-rotation about a common planetary gear axis said planetary gear set operative between a crankshaft mounted sun gear and an annular gear operatively connected to said cylinder cluster wherein said first planetary gear is engaged directly or indirectly to said sun gear and said second planetary gear is engaged directly or indirectly to said annular gear, wherein at least one of said first planetary gear and second planetary gear is a helical gear that can displace along the planetary gear axis by said phase controller to vary the phasing between said cylinder cluster and said ported member.

Preferably a rotational restrainer is provided to restrict the relative rotation between said cylinder cluster and said reciprocator so that said cylinder cluster and said reciprocator rotate at the same angular rate relative said crankshaft and said crank..

In a second aspect the present invention consists in an piston machine, comprising; a cylinder cluster of at least two cylinders rigidly located with respect to each other, and spaced about a cylinder cluster axis of rotation, each cylinder containing a complementary piston to each reciprocate along a reciprocating axis defined by its respective cylinder and each piston being of a cross section complementary the cross section of its respective cylinder, each said cylinder including at least one inlet/outlet port therefor, a crankshaft mounted for rotation relative to said cylinder cluster about a crankshaft axis that is coaxial the cylinder cluster axis of rotation, and carrying an inclined crank journal having an inclined crank axis that is oblique to the crankshaft axis but aligned to intersect therewith at an acute angle at a point X, a reciprocator mounted to rotate relative to said inclined crank journal about said inclined crank axis, said reciprocator in mechanical engagement with each piston to allow the requisite reciprocating displacement of each piston within its respective cylinder between top dead centre (TDC) and bottom dead centre (BDC) upon the crankshaft rotating relative to said cylinder cluster about the said crankshaft axis, rotational restcainer to restrict the relative rotation between said cylinder cluster and said reciprocator so that said cylinder cluster and said reciprocator rotate at the same angular rate relative said crankshaft and said inclined crank journal, a ported member relative to which said cylinder cluster in use, rotates about said crankshaft axis, said ported member including ports being comprised of a selection of inlet and/or outlet and/ or fuel injection and/or ignition ports, each of which said ports can come into cyclic communication with each cylinder in the cylinder cluster in turn via said at least one inlet/ outlet port of each cylinder, to allow fluid transfer to and from said cylinders via said ports of said ported member timed for each cylinder to coincide with the desired range of movement of a piston in a cylinder between TDC and BDC, said cylinder cluster in use, rotating with respect to said ported member about said rotary valve axis at a rotational rate indexed to the rate of rotation of the crankshaft with respect to the ported member by an indexing drive, said indexing drive controllable by a phase controlling differential input such that the angular phasing of the otherwise fixed ratio rotational indexing of the crankshaft and cylinder cluster rotation with respect to the ported member can be shifted to change fluid communication timing between the at least one inlet/ outlet port of each cylinder and the ports of the ported member relative to the range of movement of the piston in each cylinder.

Preferably said indexing drive is comprised of an epicyclic gear set said epicyclic gear set including an externally toothed sun gear concentric to said crankshaft axis and either formed as part of or rigidly mounted to or off of said crankshaft that has gear teeth that engage directly or indirectly with the teeth of one or more externally toothed planet gears dependent directly or indirectly from said ported member and said planet gears' teeth to also engage directly or indirectly with the teeth of an internally toothed annular gear either formed as part of, or mounted rigidly to said cylinder- cluster or an extension thereof and concentric to said crankshaft axis.

Preferably said planet gear(s) is/are mounted by a planet gear carrier body.

Preferably said planet gear carrier body is mounted off of said ported member or an extension thereof by bearings and has an axis of rotation coaxial with said crankshaft axis permitting rotation of said planet gear carrier body with respect to said . ported member about- said crankshaft axis over a range to allow phase shift between the ported member and the cylinder cluster.

Preferably rotation of said planet gear carrier body allows the angular location of said ports of said ported member about said crankshaft axis with respect to the angular position of said cylinder cluster about said crankshaft axis at which said pistons reach TDC to be altered by rotation of said planet gear carrier with respect to said ported member to effectively advance or retard the port timing.

Preferably the rotation of said planet gear carrier with respect to said ported member acts as a differential input to said indexing drive allowing the angular phasing of the rotational indexing between said crankshaft and said cylinder cluster with respect to said ported member to be varied.

Preferably said indexing drive is comprised of an epicyclic gear set said epicyclic gear set including an externally toothed sun gear concentric to said crankshaft axis and either formed as part of or rigidly mounted to or off of said crankshaft that has gear teeth that engage directly or indirectly with the teeth of at least one of a first planet gear dependent from and rotatable mounted relative said ported member, a second planet gear rotationally constrained relative said first planetary gear and coaxially supported thereto and relative said ported member that includes gear teeth to engage directly or indirectly with the teeth of an internally toothed annular gear either formed as part of, or mounted rigidly to said cylinder cluster or an extension thereof and concentric to said crankshaft axis, where the gear teeth angle of said first planet gear is different to the gear teeth angle of the second planet gear, said phase controlling input can displace at least the planet gear with a gear teeth angle that is not parallel to its rotational axis in a direction along its rotational axis to thereby change fluid port timing.

Preferably said machine is an internal combustion engine, timing of ignition or ^• fuel injection with respect to angle of crankshaft rotation at piston TDC can be altered appropriately by an electronic or mechanical control system to complement any changes in the port timing advance/retard.

In a further aspect the present invention consists in an axial piston internal combustion engine comprising; a cylinder cluster of at least two cylinders rigidly located with respect to each other, each said cylinder including at least one fluid inlet and/ or outlet opening, in each cylinder, a complementary piston to reciprocate along a reciprocating axis defined by its respective cylinder, a crankshaft rotatable relative to said cylinder cluster about a crankshaft axis said crankshaft carrying a crank that has a crank axis passing through said crankshaft axis at an angle, a connecting mechanism linking said pistons within said respective cylinders to said crankshaft such that the rotational motion of the crankshaft with respect to the cylinder cluster drives the reciprocal motion of the pistons within their respective cylinders or visa versa, between top dead centre (TDC) and bottom dead centre (BDC) a ported member presented so that said inlet/ outlet opening(s) of each cylinder can be sealed therewith and includes ports being comprised of a selection of at least one fuel injection port and/or at least one fuel ignition ports and/or at least one fluid inlet and/ or outlet port, each of which said ports to come into cyclic communication with each cylinder in the cylinder cluster in turn to allow fuel ignition and/or fluid transfer to and from said cylinders via said ports of said ported member timed to coincide with the desired range of movement of a piston in a cylinder between TDC and BDC, an indexing drive to transmit rotation between said cylinder cluster and said crank shaft to, in use, rotate said cylinder cluster relative said ported member about said crankshaft axis at a rotational rate indexed to the rate of rotation of the crankshaft thereby, operatively presenting said inlet/ outlet openings to each of said ports for cyclic communication with the inlet/ outlet openings of each cylinder in the cylinder cluster in turn, corresponding to the desired phase of motion of a said piston in its respective cylinder between its top dead centre and bottom dead centre positioning relative to its angular position about said crankshaft axis with respect to the ported member, an indexing drive phase controller to change the configuration of the indexing drive to thereby vary the angular phasing between the cylinder cluster and the ported member and thereby, for each cylinder, change the range of motion of the piston between top dead centre and bottom dead centre at which said inlet/ outlet opening is in communication with the ports of the ported member.

Preferably said indexing drive is an epicyclic drive comprising of a sun gear engaged to the crankshaft and rotationally constrained thereto to rotate about the crank shaft axis, said sun gear coupled via at least one planetary gear to annular gear, one engaged to one of each of the cylinder cluster and ported member, said phase controller coupled to one of said planetary gear and said annular gear and said sun gear to cause it to be displaced to thereby cause a phase shift to occur.

In still a further aspect the present invention consists in, in a Z-crank axial piston internal combustion engine that includes (i) a cylinder cluster of at least two piston containing cylinders rigidly located with respect to each other, each said cylinder including at least one working fluid transfer port (ii) a crankshaft rotatable relative to said cylinder cluster and carrying an angled crank about which a reciprocator can rotate that is in mechanical connection with the pistons and (iii) a ported member relative to which the cylinder cluster rotates and that can seal the at least one fluid transfer port of each 'cylinder yet offers, at intervals, their exposure to spark plug(s) and/or working fluid delivery and removal facilities, an indexing drive to transmit rotation between said cylinder cluster and said crank shaft to, in use, rotate said cylinder cluster relative said ported member about said crankshaft axis at a rotational rate timed to coincide with the desired range of movement of the piston in each cylinder between TDC and BDC, and an indexing drive phase controller to change the configuration of the indexing drive to thereby vary the angular phasing between the cylinder cluster and the ported member and thereby, for each cylinder, change the range of motion of the piston between top dead centre and bottom dead centre at which said at least one fluid transfer port is in communication with said facilities.

In yet a further aspect the present invention consist in a Z-crank axial piston internal combustion engine comprising; a cylinder cluster of at least two piston containing cylinders rigidly located with respect to each other, each said cylinder including at least one working fluid transfer port, a crankshaft rotatable relative to said cylinder cluster and carrying an angled crank about which a reciprocator can rotate that is in mechanical connection with the pistons and a ported member relative to which the cylinder cluster can rotate and that can seal the at least one fluid transfer port of each cylinder yet offers, at intervals, their exposure to spark plug(s) and/ or working fluid delivery and removal facilities, an indexing drive to transmit rotation between said cylinder cluster and said crank shaft to, in use, rotate said cylinder cluster relative said ported member about said crankshaft axis at a rotational rate timed to coincide with the desired range of movement of the piston in each cylinder between TDC and BDC, and an indexing drive phase controller to change the configuration of the indexing drive to thereby vary the angular phasing between the cylinder cluster and the ported member and thereby, for each cylinder, change the range of motion of the piston between top dead centre and bottom dead centre at which said at least one fluid transfer port is in communication with said facilities.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incdrporated herein as if individually set forth.

As used herein the term "and/or" means "and" or "or", or both.

As used herein "(s)" following a noun means the plural and/or singular forms of the noun.

The term "comprising" as used in this specification means "consisting at least in part of. When interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in the same manner.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

The invention consists of the foregoing and also envisages constructions of which the following gives examples. BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described with reference to the accompanying drawings in which;

Figure 1 is a cross sectional view of an axial piston engine, omitting some details and components necessary for construction, having a counter rotating cylinder cluster and crankshaft and showing a preferred epicyclic port indexing drive incorporating an adjustment mechanism for port timing control,

Figure Ia is a view of the preferred epicyclic drive of Figure 1 viewed along the axis of the crankshaft from the end of the engine closest to the epicyclic drive and showing detail of the advance retard mechanism,

Figure Ib is a perspective view of a section through the engine of Figure 1 and Figure Ib showing further detail of the advance retard mechanism and the epicyclic drive,

Figure 2 is a partial cross sectional view of the engine of Figure 1 with the port indexing drive adjusted to be in a position to advance the port timing,

Figure 3 is a partial cross sectional view of the engine of Figure 1 and 2 with the port indexing drive to be ,in a position to retard the port timing,

Figure 4 is a graph showing the port timing for normal (not advanced nor retarded) and retarded port timing such as might be representative of the planet carrier positions of Figure 1 and Figure 3 respectively,

Figure 5 is a perspective view of a rotation restraint mechanism that may be used in the axial piston engine herein described,

Figure 6 is a section view of part of an axial piston engine of the present invention with certain detail removed for clarity purposes, and showing an alternative rotation restraint mechanism to that shown in figure 5,

Figure 7 shows the rotation restraint arms that may be used as part of the rotation restraint mechanism shown in figure 6,

Figure 8 shows a perspective view of a dual plane epicyclic drive with helical cut or spiral cut gear teeth,

Figure 9 shows the components as per figure 8 but in a different orientation relative each other,

Figure 10 is a side view of figure 8,

Figure U is a side view of figure 9,

Figure 12 is an alternative perspective view of figure 8,

Figure 13 is an alternative perspective view of figure 9,

Figure 14 is a spreadsheet showing whole number solutions for gear selection for a dual plane gearset as per figure 8, and Figure 15 is a spreadsheet of an expanded range to that of figure 14 without the detail of figure 14 provided for graphical illustrative purposes only.

DETAILED DESCRIPTION OF THE INVENTION

Reference will herein predominantly be made to a four stroke version of an axial piston engine, utilising a Z-crank. However it will be appreciated by a person skilled in the art how what is described can be applied to two stroke axial piston engines and axial piston engines or pumps utilising Swashplate drives or otherwise.

Figure 1 is a cross-sectional view of a simplified four-stroke five cylinder axial piston engine omitting some of the details necessary for construction for the sake of clarity. The ported member 2 has three sets of inlet ports 4, exhaust ports 6 and spark plug or fuel injection orifices 8 passing through it, though only some of all the ports are visible in this cross sectional view. The ports and orifices have a rotational symmetry of order three around the crankshaft axis 16.

The inlet ports 4 and exhaust ports 6 may have inlet and exhaust manifolds (not shown) respectively attached to them to guide the inlet and exhaust flow.

The ported member 2 is mounted rigidly to an engine casing 10.

A cylinder cluster 12 comprising of five cylinders 14 equi-spaced around the crankshaft axis 16 is provided. Cylinders may be cooled by a liquid coolant circulated through coolant galleries 46. The engine or machine of the present invention may be configured of any number of cylinders though 3 or more is preferred. Where the machine is operating as an internal combustion engine, fluid that passes through the ports may be a fuel and/or fuel/air mixture.

Each of the cylinders has a cylinder opening 48 (there may be more than one opening per cylinder) that comes into cyclic communication with each of the ports 4, 6 and spark^' plug or fuel injection orifices 8. By way of a sliding face seal 50 a seal between the cylinder head and face of the ported member 2 can be maintained.

The cylinder openings 48 of each cylinder may be provided direcdy at the main combustion zone and each cylinder or at an extension therefrom.

Each cylinder 14 contains a piston 18 (shown in figure 1 at TDC) linked to a connection rod 20 by means of a rotational joint 22 (that in this diagram is simplified for clarity). Each piston 18 is of a cross section matched to the cross section of its respective cylinder 14. The connection rod 20 is in turn linked to the reciprocator 24 through a rotational joint 26, (also- simplified for clarity). The reciprocator is mounted on combined radial and thrust bearings 28, 30 on an inclined crank journal 32 that is formed as part of the crankshaft 34 and that has an inclined crank axis 36 that intersects with the crankshaft axis 16 at an acute angle at a point X.

The reciprocator 24 is restricted against rotation with respect to the cylinder cluster 12 by a rotation restraint mechanism. This may be comprised of two gimbal arms 52, 54 mounted on bearings off of the cylinder cluster 12 and the reciprocator 24 respectively and linked together by a spherical joint 56. This ensures operational synchronicity between the reciprocator and the cylinder cluster.

In Figure 5 there is shown part of the components of the rotational restraint mechanism that includes the two gimbal arms 52 and 54. The lower gimbal arm 54 is mounted to rotate with the reciprocator and can pivot about pivot axis 148 by for example journaled bearings 170. The upper gimbal 52 is mounted to the cylinder cluster 12 by the journals 172. The journals 172 allow for relative rotation between the gimbal 52 and the cylinder cluster to occur about axis 146. The gimbal link joint 56 allows for appropriate rotational degrees of freedom between the reciprocator gimbal 54 and the cylinder gimbal 52, yet allows for a torque transfer to occur there between.

Figure 6 shows an alternative torque restraint mechanism wherein a plurality of gimbal arms pairs are provided. Towards the right hand side of the engine a sectional view through a pair of gimbal arms 102 and 104 is shown. The cylinder gimbal arm 102 is joined to the cylinder cluster 12 at rotational joint Cl. It is also joined to the reciprocator gimbal 104 at the rotational joint Tl. The reciprocator gimbal 104 is connected to the reciprocator at rotational joint Rl. Figure 6 shows a partial cross section of a five axial piston engine in which many components have been simplified and/or omitted for clarity in order to illustrate the layout and geometry of an alternative rotation restraint system employing multiple rotation arm pairs.

In this multi-arm rotation restraint configuration a number of identical pairs of gimbal arms equal to the number of cylinders is arrayed about the engine in a symmetrical manner. Each pair of gimbal arms being comprised of: a cylinder gimbal arm 102 pivotably mounted on a cylinder gimbal arm binge axis Cl as part of or attached to the cylinder cluster 12. The pivot mount allows the cylinder gimbal arm 102 to rotate with respect to the cylinder cluster 12 about an axis perpendicular to the crankshaft axis, while restraining any motion along the cylinder gimbal arm hinge axis Cl. A reciprocator gimbal arm 104 is pivotably mounted on a reciprocator gimbal arm hinge axis Rl off of the reciprocator 24. The pivot mount allows the reciprocator gimbal arm 104 to rotate about an axis perpendicular to the crank axis, relative to the reciprocator 24 while preventing any motion along the reciprocator gimbal arm hinge axis Rl .

The cylinder gimbal arm 102 and the reciprocator gimbal arm 104 of each gimbal arm pair in the multi arm reaction configuration are linked together by a universal tip joint possessing three rotational degrees of freedom that intersect at a point Tl. In the case of Fig 6 a spherical bearing is used for simplicity, though other tip joint configurations having three intersecting rotational degrees of freedom may be more advantageous. The point Tl of the tip joint is at an identical distance from the respective pivoting hinge axes Rl and Cl of the gimbal arm pairs and in operation the locus of the tip joints Tl for all of the pairs of gimbal arms will always lie on the medial plane M which in figure 6 is in an instantaneous orientation perpendicular to the plane of the drawing. This implies and requires that the pivoting hinge axes Rl and Cl of each pair of rotation arms be exact mirrors of each other in the medial plane M, or in other words the cylinder gimbal arm hinge axis Cl must be exactly the same distance from the crankshaft axis 16 and point X as the reciprocator gimbal arm hinge axis Rl is from the crank axis 36 and point X respectively, to ensure homo-kinetic operation of the multiple rotation arm rotation restraint system.

AU the cylinder gimbal arm hinge axes and all the reciprocator gimbal arm hinge axes are positioned to be rotationally symmetric about the crankshaft axis 16 and crank axis 36 respectively. They are preferably located between the connection rod 20 to reciprocator 24 rotational joints 26 as shown to allow for a more compact implementation of the multiple gimbal arm rotation restraint system. The bearings of the cylinder gimbal arm hinge axes and the bearings of the reciprocator gimbal hinge axes must be able to withstand operation with substantial loads applied to them both parallel and perpendicular to their hinge axes as each arm applies a significant moment and inertial load to its hinge mount, the moments in particular should have relatively large axial spacings between the bearings that form the hinge axes as is illustrated by the example of reciprocator gimbal hinge bearings 106 that form one of the reciprocator gimbal arm hinge axes. The total rotation restraint required is shared between the multiple pairs of gimbal arms, so that the individual arms and their bearings need only take a proportion of the total load and may thus be made individually smaller than for a single pair of rotational restraint gimbals as shown in Figure 5. In order to ensure that sharing of the total restraining rotation occurs between the multiple pairs of gimbal arms 102, 104 etc a small degree of compliance may be useful either in the form of slight bending of the rotation arms 102, 104 themselves in response to applied loads at Tl parallel to their respective hinge axes Rl or Cl, or alternatively from a small amount of sprung axial compliance in the thrust bearings of the rotation arms' respective hinge axes Rl, Cl.

The rotationally symmetric positioning of the gimbal arm 'pairs means that for engines with three or more rotation arm pairs the inertial forces and moments produced by the motion of the rotation arms may be almost completely balanced out by suitable balance masses attached to the crankshaft, thereby resulting in an engine with less noticeable vibrations. By offsetting the hinge axes Cl, Rl radially outwards from the crankshaft axis 15 and crank axis 36 respectively there is more space made available for the structure of the reciprocator 24, its bearings and the crankshaft front balance mass 142.

Figure 7 shows detail of the arms of Figure 6 with an alternative design of universal tip joint for the multiple gimbal arm pairs that instead employs a compound joint possessing three independent and intersecting rotational degrees of freedom. All components excepting the crankshaft and five rotation arm pairs (two of which are directly behind other rotation arm pairs and so are completely obscured) are hidden for clarity. The cylinder gimbal arm 102 pivots about the cylinder arm hinge axis Cl on two coaxial radial bearing for example 114 and for thrust. The cylinder gimbal arm 102 incorporates a complementary cylinder arm forked knuckle that rotates about axis Vl with respect to the cylinder arm 102 on two axially separated bearings at location 114 that also prevent axial movement of the cylinder arm forked knuckle along the axis Vl with respect to the cylinder gimbal arm 102. The reciprocator gimbal arm 104 pivots about the reciprocator gimbal arm hinge axis Rl on two coaxial radial bearings and thrust bearings. The reciprocator gimbal arm 104 incorporates a complementary reciprocator arm clevis knuckle 130 that rotates about axis Ul with respect to the gimbal reciprocator arm 104 on two axially separated bearings that also prevent axial movement of the reciprocator gimbal arm clevis knuckle 130 along the axis Ul with respect to the reciprocator arm 104. The cylinder arm forked knuckle 118 and the reciprocator gimbal arm clevis. knuckle 130 are linked together in the fork-and-clevis type knuckle pivot by radial and thrust bearings that allow them to rotate with respect to each other about the tip hinge axis Wl which is perpendicular to the axes Ul and Vl. All three axes Ul, Vl, Wl intersect at tip joint point Tl which lies on the medial plane M (not shown).

The gimbal arm bearings may be foiling element or plain bearings, but if plain bearings are utilised then in some cases it may be necessary to utilised floating bushes and/or thrust washers in order to reduce the friction and wear of the bearings. For example in the implementation depicted in Figure 7 the knuckle pivot is subjected to a greater range of angular motion than are the other rotation arm bearings and may benefit significantly from the utilisation of floating bearings.

In use, as the. crankshaft 34 rotates with respect to the cylinder cluster 12 the reciprocator 24 moves the pistons 18 to reciprocate in their respective cylinders 14.

Whilst reference herein may be made axial piston machines where the pistons may travel parallel to each other and parallel to the crank shaft, it is also to be understood to covet a configuration where the pistons move at an incline to each other and to the crank shaft.

The crankshaft 34 may be supported in bearings 38, 40, 42, 44 and 45. In the configuration shown it rotates in a clockwise direction when viewed from the end of the engine proximal more to the ported member 2. The cylinder cluster 12 rotates in the opposite direction to the crankshaft with respect to the ported member 2 at a rate equal to one fifth that of the crankshaft for the four-stroke five cylinder engine depicted in order to create the required synchronisation of port timing with piston motion. Different rates of co or counter rotation may be required where different^' cylinder numbers are provided. This is described in greater detail in US Patent 6,494,171.

The relative rates of rotation of the crankshaft 34 and cylinder cluster 12 with respect to the ported member 2 are controlled by an indexing drive. Referring also to Figures Ib and Ic this is provided by an epicyclic gear set in this preferred embodiment and is comprised of an annular gear 58, a sun gear 60 and three planet gears 62 mounted off of a planet gear carrier 64 on bearings 66.

The annular gear 58 is attached to the cylinder cradle 68 that is mounted off of or formed as part of the cylinder cluster 12. The cylinder cradle defines a connection between the cylinder cluster 12 and the annular gear 58 so that they remain stationary, relative to each other. The sun gear 60 is mounted off of or formed as part of the crankshaft 34. The sun gear 60 and crankshaft 34 remain stationary relative to each other.

The planet gear carrier 64 is mounted in a plain bearing 70 in the engine casing 10 that allows the planet gear carrier to be rotated about the crankshaft axis 16 and relative the engine casing 10 and the ported member 2. While crankshaft bearing 45 runs between the planet gear carrier 64 and the crankshaft 34, it could equally be relocated to run between the casing 10 and the crankshaft 34.

The rotational axes of all the planets, annular gear and sun gear are parallel to each other.

Rotation of the planet gear carrier 64 with respect to the ported member 2 allows the timing of all port openings and closings to be identically and simultaneously advanced or retarded with respect to the reciprocal motion of the pistons 18 within their respective cylinders 14.

The rotation of the planet gear carrier 64 may be controlled by an arm 72 formed as part of or affixed to and extending from the planet gear carrier 64. The arm is fitted with an adjustment nut 74 that can effect a rotation of the arm 72 to allow it to align with the rotating adjustment screw 76 that has a thread 78 that engages in the adjustment nut 74. The adjustment screw 76 is also mounted into a plain bearing having two opposing thrust faces 80, 82 in the engine casing 10 that makes it possible to rotate the adjustment screw 76 about its axis using the screw head 84 while preventing any movement of the adjustment screw 76 along its axis with respect to the engine casing 10. The port timing advance-retard can thus be adjusted by rotation of the adjustment screw 76. The use of a screw adjustment 76 has the advantage that the friction of the adjustment screw thread and plain bearings 80, 82 in the casing 10 can provide a degree of self locking to the mechanism to reduce the need for a consistently applied holding force when the advance retard mechanism is not being ^' adjusted.

Figure 2 shows a partial cross section of the same engine as in Figure 1, but with the port timing adjusted by rotation of the planet carrier 64 about the crankshaft axis 16 with respect to the ported member 2 by means of adjustment screw 76 to advance the port timing. This means that the piston 18 has already passed its TDC position and is descending towards BDC within the cylinder 14 as the cylinder cluster 12 comes to exactly the same angular position with respect to the ported member 2 as it had in Figure 1. Advancing the port timing is accomplished by rotation of the planet earlier about the crankshaft axis 16 with respect to the ported member 2 in the same direction that the crankshaft 34 rotates.

Figure 3 shows another partial cross section of the same engine as in Figure 1 and Figure 2, but with the port timing adjusted by rotation of the planet carrier 64 about the crankshaft axis 16 with respect to the ported member 2 by means of adjustment screw 76 to retard the port timing. This means that the piston 18 is still rising from BDC towards its TDC position within the cylinder 14 as the cylinder cluster 12 comes to exactly the same angular position with respect to the ported member 2 as it had in Figure 1 and Figure 2. Retarding the port timing is accomplished by rotation of the planet carrier about the crankshaft axis with respect to the ported member 2 in the opposite direction to that in which the crankshaft rotates.

Figure 4 is a graph showing the general effect on port timing and opening areas of retarding the port timing from that shown in Figure 1 to a position similar to that shown in Figure 3. The top of the two graphs shows a port timing graph illustrative of the port timing of the four-stroke engine configuration shown in Figure 1 and similar to what might be found in many conventional spark ignition engines. The exhaust port opens significantly before the piston reaches BDC on the expansion stroke and allows the exhaust gases to exit the cylinder reducing the cylinder pressure before the start of the exhaust stroke, with the exhaust port closing just after the piston reaches TDC at the end of the exhaust stroke. The inlet port opens just before the piston reaches TDC on the exhaust stroke and remains open during the inlet stroke closing significantly after the piston has passed BDC part way through the compression stroke.

By contrast the bottom of the two graphs of Figure 4 shows a port timing graph similar to that of the engine of Figure 3 in which the port opening areas, the duration of the port openings and the port opening overlap between the exhaust and inlet ports remain the same as for the engine of Figure 1, but they are all delayed (retarded) in their occurrence with respect to the timing of the engine of Figure 1. This means that the exhaust port opening occurs closer to BDC on the expansion stroke and the cylinder pressure is likely to be higher at the start of the exhaust stroke, the exhaust port does not close and the inlet port does not open until well into the inlet stroke so that a significant amount of exhaust gas remains in the cylinder to mix with the incoming inlet air. The inlet port does not close until quite late in the compression stroke and a lot of the air mixture in the cylinder is pumped back out of the inlet port before it is closed leaving less air in the cylinder for compression.

Retarding of the port timing as shown in Figure 3 and in the bottom graph of Figure 4 may have significant efficiency and emissions benefits for spark ignition engine operation at part load (part throttle) and low speeds, combining the known benefits of high exhaust gas recirculation and late inlet port closure. The large amount of exhaust gas re-circulated into the inlet gases may increase the temperature of the inlet gases and means that even though there is less air in the cylinder and a lower effective compression ratio owing to the late close of the inlet port, the temperature achieved at the end of the compression stroke may still be high enough to permit ignition of the air-fuel mixture. This may reduce the need for inefficient inlet air throttling as a means for making it possible to run the engine at low loads and may also permit the use of leaner fuel- air mixtures. The late opening of the exhaust port may also mean that more energy can be extracted from the high pressure combustion gases during the expansion stroke. The combination of less gas being present in the cylinder for the compression stroke coupled with a longer expansion stroke may result in the gases being expanded to close to ambient pressure during the expansion stroke wliich may yield greater energy utilisation with only relatively small losses due to higher than ambient cylinder pressures at the start of the exhaust stroke.

Though not shown the adjustment screw 76 could be rotated by a servo .motor or other rotary drive controlled by an engine control system that could thereby advance or retard the port timing in response to changes in engine speed and/or power demands and/or exhaust emissions in order to achieve greater engine power and/or reduce various exhaust emissions.

Figures 8 to 13 describe helical gears in a dual plane planetary gear set used for the purposes of an advance/retard method. Figures 8, 10 & 12 show three different perspectives of the helical planetary gear set in the forward position corresponding to a 'advanced' condition.

Figures 9,11,13 describe three different perspectives of the helical planetary gear set in the retracted position corresponding to a 'retarded' condition.

Figure 8 shows a dual plane planetary gear set that includes a first planetary gear 62A and a second planetary gear 62B. Multiple pairs of planarity gears may be provided on an equispaced PCD. The gears are of a helical or spiral cut nature. The two planetary gears share a common axis 88 and are positioned spaced apart along this axis. The gear 62A may be of a different size to the gear 62B. They may be the same. They may move together in a direction along the axis 88. This may be achieved by their being supported by appropriate bearings or splined onto a shaft.

The planetary axis 88 remains stationary to the engine housing body. The planetary gear set, comprising of the first planetary gear 62A in transmission with the sun gear 60 attached to the crankshaft 16, and the second planetary gear 62B in transmission with the cylinder annulus 58 that is in turn connected to the cylinder group, can move or be moved by input from a person of automatically (such may include engine performance characteristic feedback) along the planetary axis 88. In figure 8, the position of the planetary gear set is shown in the forward position and that corresponds to the 'advanced' condition operation of the engine. An actuator of some method such as a hydraulic ram, electric motor driven cam or screw can be employed to forcibly control the axial position of the planetary gear set. By the nature of the helical angle of the gears, for any non identical helical angle combination of 'first plane' gear set and/or 'second plane' gear set, any axial displacement of the planetary gear set will provide a small amount of rotational phase shift between the angular position of the crankshaft relative to the cylinder group, thus providing active advance and retard of the piston timing event relative to the stationary porting member.

The helical cut gear angle of the first planetary gear 62A is preferably opposite to the angle of the second planetary gear 62B.

Only one of the first and second planetary gears may be helical cut, the other may be square cut. Where both are helical cut, their helix angle does not need to be the same. The angle may be mirror imaged about a mirror line to which the planetary gear axis 88 is normal or may be in the same direction but then not of the same helix angle. If it were the same and not opposed, then the planetary gear set would just screw itself around the helix with no net differential rotation between the sun and annulus gears.

Only one of the planetary gears of the planetary gear set may be displaceable along the planetary axis whilst the other stays stationary. In this case, the displaceable planetary gear is a helical gear and mates with or is in operative engagement with a corresponding helical gear being one of the sun and annular gears. One of the planetary gears may be in a sliding, splined, engagement with a planetary gear shaft. Whilst the planetary gear or gears are preferably in direct contact with the sun and annular gear, it may be possible that intermediate gears are provided, thereby establishing an "operative" but not necessarily direct coupling of the sun and annular gear with the planetary gear(s).

Figure 9 is the same configuration as in Figure 8 above, but in this instance, the planetary gear set is shown in the retracted position that corresponds to 'retarded' condition of operation of the engine.

The required gear ratio between the cylinder cluster and the crankshaft must be an integer number equal to the number of working cylinders. For the sake of this example the ratio shall be 5:1 which corresponds to a 5 cylinder, cylinder cluster. F'or a dual plane planetary gear arrangement as shown in figure 8 the formula to calculate the required gear PCD's (or number of teeth if the gear modules are identical) can be described as:

Na = (Ns2 + NsxNpl) and: Np2 = Na - Ns - NpI

Ns - Npl/R

where: Ns = PCD of Crankshaft Sun Gear Na = PCD of Cylinder Annulus

NpI = PCD of First Planetary Gear communicating with Sun Gear Np2 = PCD of Second Planetary Gear communicating with Cylinder Annulus R = Reduction Ratio Integer (Number of Cylinders)

A spread sheet can then be used to find the whole number options that can support the required ratio. A part of such a spreadsheet is shown in figure 14. The whole-number solutions are clearly apparent. Figure 15 is of an enlarged range of the spreadsheet of figure 14 shown for graphical illustrative purposes.

Figure 15 has a diagonal line through the middle •illustrating a characteristic set of whole number solutions that have a less-than-desirable makeup of ratios, in this case 5:1 ratio example relating to a first stage ratio (Ns/Npl) of 2:1, followed by a second stage ratio (Np2/Na) of 2.5:1. The reason this line of solution is less-than-desirable is because of the introduction of harmonics and uneven wear characteristics such ratios would have. Ratios that fall above the diagonal line above tend to have a 'Short & Stout' nature where the overall arrangement of the gear-set is compact with smaller overall PCD's, while below the line the ratios tend to be 'Tall and Skinny' with much larger PCD's. Usually compactness is a requirement of a practical design, and that is where a selection above the diagonal line will appear to be desirable.

Further inspection of the above spreadsheet will also highlight that there are other 'lines' of coincidence, and such lines of coincidence usually relate to undesirable modes.

What is also apparent is that there are pockets of essentially 'prime' solutions which a worthy of targeting because of their ability to ensure even wear characteristics and non- harmonic inducing operation.

Another consideration is the number of teeth that would form the basis of selection with regards to the Module (PCD/No Teeth) of the gear tooth profile. If one was to use the spreadsheet as the basis of the number of teeth, then it would be desirable for all of the gears of the gear-train to have the number of teeth fall within the range of between 15 to 150 teeth. Any gear that has less than about 15 teeth becomes too course, and contrastingly, a gear that has a number of teeth greater than about 150 teeth becomes too fine and would have compromised strength. While the selection described above is based on the whole number of teeth or PCD's of the first ratio of Ns/Npl and must be adhered to, it is conceivable that the second ratio of Np2/Na could have a number of solutions. depending on the module of the tooth form.

One such example that can be gleaned from the above spreadsheet is an Ns/Npl ratio of 28/44, followed by Np2/Na ratio of 33/105, giving two distinctly prime ratios of 0.63636363:1, and 0.31428571:1.

This set of ratios follow all the desired criteria set out above, and exploring the second ratio set of 33/105 or 0.31428571:1, it can be seen that for example 22/70 has the exact same ratio of 0.31428571:1, but would require gears of a larger module to obtain the requisite PCD.

As per Figure 8 above, figure 10 shows the planetary from a different perspective. Likewise figure 11 is a different perspective to that of figure 9. Figure 12 shows a position corresponding to the 'advanced' condition. Figure 12 shows a position corresponding to the 'retarded' condition. The machine or engine as herein described may include other features that may- provide some benefits. Such are decribed in co existing complete specifications of NZ 560589 and NZ 560587.

Where reference here in is made to "rotation about" or similar, such as "rotation about the crankshaft axis" it is to be understood that is could mean to refer to a complete revolution or revolutions or partial revolution about for example the crankshaft axis.

The engine or machine of the present invention may be configured of any number of cylinders though 3 or more is preferred. Where the machine is operating as an internal combustion engine, fluid that passes through the ports may be a fuel and/or fuel/ air mixture.

The cylinder cluster as herein referred to can be a cylinder block that has cylindrical bores provided therein. Alternatively it may be comprised of discrete cylinders that are affixed to each other by way of a frame or the like. Each cylinder defines a combustion chamber where the present invention is provided to operate as an internal combustion engine.

Claims

1. An axial piston internal combustion engine comprising; a cylinder cluster comprising of at least two cylinders rigidly located with respect to each other, each cylinder spaced relative to the other(s) and about a cylinder cluster axis, each said cylinder including at least one cylinder opening for fluid inlet and/or outlet to and/ or from said cylinder, in each cylinder, a complementary piston to reciprocate along a reciprocating axis defined by its respective cylinder, a crankshaft rotatable relative to said cylinder cluster about a crankshaft axis that is coaxial with the cylinder cluster axis, said crankshaft carrying a crank that has a crank axis passing through said crankshaft axis at an angle, a reciprocator rotatably mounted by said crank to rotate about said crank axis and about said crank, said reciprocator operatively connecting said pistons with said crank such that the rotational motion of the crankshaft with respect to the cylinder cluster drives the reciprocal motion of the pistons within their respective cylinders or visa versa, and allows consistent and controlled reciprocating displacement of each piston within its respective cylinder between top dead centre (TDC) and bottom dead centre (BDC) a ported member presented to facilitate a sealing of said at least one cylinder opening of each cylinder, said ported member including ports being comprised of a selection of at least one fuel injection port and/or at least one fuel ignition port and/or at least one fluid inlet port and at least one fluid outlet port positioned to allow fluid communication via said at least one cylinder opening of a cylinder to be separately established, indexing drive to transmit rotation between said cylinder cluster and said crank shaft to, in use, rotate said cylinder cluster relative said ported member about said crankshaft axis at a rotational rate indexed to the rate of rotation of the crankshaft thereby operatively ^■ presenting said cylinder openings to some or each of said ports to allow their cyclic communication with each cylinder^'in turn, at instances corresponding to the desired positions in the cyclic reciprocating motion of a said piston in its respective cylinder between its TDC and BDC positioning, an indexing drive phase controller to allow controlled variation of the angular phasing between the cylinder cluster and the ported member and thereby vary the location for each piston in its range. of motion between TDC and BDC at which each said cylinder opening comes into communication with a port of the ported member.

2. An engine as claimed in claim 1 wherein the angular phasing of the otherwise fixed ratio rotational indexing of the crankshaft and cylinder cluster rotation with respect to the ported member can be varied by an indexing drive positional adjuster that can adjust the indexing drive positional relationship relative said ported member.

3. An engine as claimed in claim 1 wherein said indexing drive opera tively acts intermediate of said cylinder cluster and said crankshaft and comprises a crankshaft mounted sun gear to rotate with said crankshaft about the crankshaft axis and an annular gear operatively connected to said cylinder cluster to rotate with said cylinder cluster about said crankshaft axis, and. at least one intermediate planetary gear operative between said sun gear and said annular gear, said at least one planetary gear mounted relative said ported member.

4. An engine as claimed in claim 3 wherein said at least one planetary gear is held in a fixed angular position relative said crankshaft axis relative to the ported member, save for any indexing drive phase controller effected angular positional variation thereof relative said crankshaft axis, to vary the angular phasing between the cylinder cluster and the ported member.

5. An engine as claimed in claim 1 wherein said phase controller includes a carrier (preferably a spider arm) mounted with an axis of rotation coaxial the crankshaft axis, said carrier mounting at least one planetary gear that can rotate about a planetary gear axis relative to said carrier and is operative intermediate of a crankshaft mounted sun gear and an annular gear operatively connected to said cylinder cluster, said carrier being controlled for rotation to vary the angular position of the planetary gear about said crankshaft axis relative to the ported member to thereby vary the phasing between said cylinder cluster and said ported member.

6. An engine as claimed in claim 5 wherein a positional adjuster is provided to adjust the angular position of the planetary gear relative said, crankshaft axis with respect to the ported ^• member.

7. An engine as claimed in claim 6 wherein the positional adjuster acts on the carrier and is actuable from remote of the engine.

8. An engine as claimed in anyone of claims 3 to 7 wherein there are at least 3 planetary gears operative intermediate of the sun gear and the annular gear.

9. An engine as claimed in claim 1 wherein the indexing phase controller is capable of said controlled variation while said engine is operating.

10. An engine as claimed in claim 9 wherein any said controlled variation is performed in response to an electronic engine control system to permit performance optimisation during engine operation.

11. An engine as claimed in any one of the preceding claims wherein timing of ignition or fuel injection can be altered appropriately by an electronic or mechanical control system to complement any changes in the angular phasing.

12. An engine as claimed in any one of the preceding claims wherein said ported member is stationary and said cylinder cluster, crankshaft and reciprocator all move relative thereto.

13. An engine as , claimed in any one of the preceding claims wherein said crankshaft rotates in the opposite direction to the cylinder cluster relative a fixed reference that is stationary to said ported member.

14. An engine as claimed in any one of the preceding claims wherein a rotation restraint mechanism is operative between said cylinder cluster and said reciprocator to ensure the rotational speed of the cylinder cluster and reciprocator relative the ported member is synchronous.

15. An engine as claimed in claim 1 wherein the phase controller allows, by changes to the angular phasing between the rotation of said crankshaft and said cylinder cluster with respect to said ported member , the alteration of the angular location of said ports of said ported member about said crankshaft axis with respect to the angular position of said cylinder cluster about said crankshaft axis at which said pistons reach TDC, thus allowing the timing of fluid port opening and closing events of the cylinder opening with respect to the reciprocating motion of their respective pistons to be advanced and retarded.

16. An engine as claimed in any one of the preceding claims wherein said engine is a Z- Crank engine, and preferably an internal combustion Z-Crank engine wherein the fluid used is a fuel and/or fuel/ air mixture.

17. An engine as claimed in any one of the preceding claims wherein said cylinder defined reciprocating axis of each piston is parallel to the crankshaft axis.

18. An engine as claimed in any one of the preceding claims wherein said cylinder cluster includes three or more cylinders.

19. An engine as claimed in claim 1 wherein said indexing drive includes a planetary gear set that comprises a first planetary gear and a second planetary gear that rotationally constrained relative each other and are each presented for co-rotation about a common planetary gear axis said planetary gear set operative between a crankshaft mounted sun gear and an annular gear operatively connected to said cylinder cluster wherein said first planetary gear is engaged directly or indirectly to said sun gear and said second planetary gear is engaged directly or indirectly to said annular gear, wherein the gear tooth angle of one of said first planetary gear and second planetary gear is different to the other, and wherein said phase controller can effect a displacement of said planetary gear set along the planetary gear axis so as to vary the phasing between said cylinder cluster and said ported member.

20. An engine as claimed in claim 19 wherein a positional adjuster is provided to adjust the position of the planetary gear set along the planetary gear axis.

21. An engine as claimed in claim 19 or 20 wherein said first planetary gear is a helical cut gear.

22. An engine as claimed in anyone of claims 19 to 21 wherein said first planetary gear and said sun gear are complementary helical cut gears and are in direct contact with each other.

23. An engine as claimed in anyone of claims 20 to 22 wherein said second planetary gear is square cut.

24. An engine as claimed in claim 21 wherein said second planetary gear is a helical cut gear and that is has a helix angle that is not parallel to the helix angle of the first planetary gear.

25. An engine as claimed in claim 1 wherein said indexing drive includes a planetary gear set that comprises a first planetary gear and a second planetary gear that are each rotationally constrained relative each other and are presented for co-rotation about a common planetary gear axis said planetary gear set operative between a crankshaft mounted sun gear arid an annular gear operatively connected to said cylinder cluster wherein said first planetary gear is engaged directly or indirectly to said sun gear and said second planetary gear is engaged directly or indirectly to said annular gear, wherein at least one of said first planetary gear and second planetary gear is a helical gear that can displace along the planetary gear axis by said phase controller to vary the phasing between said cylinder cluster and said ported member.

26. An engine as claimed in claim 1 wherein a rotational restrainer is provided to restrict the relative rotation between said cylinder cluster and said reciprocator so that said cylinder cluster and said reciprocator rotate at the same angular rate relative said crankshaft and said crank..

27. An piston machine, comprising; a cylinder cluster of at least two cylinders rigidly located with respect to each other, and spaced about a cylinder cluster axis of rotation, each cylinder containing a complementary piston to each reciprocate along a reciprocating axis defined by its respective cylinder and each piston being of a cross section complementary the cross section of its respective cylinder, each said cylinder including at least one inlet/ outlet port therefor, a crankshaft mounted for rotation relative to said cylinder cluster about a crankshaft axis that is coaxial the cylinder cluster axis of rotation, and carrying an inclined crank journal having an inclined crank axis that is oblique to the crankshaft axis but aligned to intersect therewith at an acute angle at a point X, a reciprocator mounted to rotate relative to said inclined crank journal about said inclined crank axis, said reciprocator in mechanical engagement with each piston to allow the requisite reciprocating displacement of each piston within its respective cylinder between top dead centre (TDC) and bottom dead centre (BDC) upon the crankshaft rotating relative to said cylinder cluster about the said crankshaft axis, rotational restrainer to restrict the relative rotation between said cylinder cluster and said reciprocator so that said cylinder cluster and said reciprocator rotate at the same angular rate relative said crankshaft and said inclined crank journal, a ported member relative to which said cylinder cluster in use, rotates about said crankshaft axis, said ported member including ports being comprised of a selection of inlet and/or outlet and/or fuel injection and/or ignition ports, each of which said ports can come into cyclic communication with each cylinder in the cylinder cluster in turn via said at least one inlet/outlet port of each cylinder, to allow fluid transfer to and from said cylinders via said ports of said ported member timed for each cylinder to coincide with the desired range of movement of a piston in a cylinder between TDC and BDC, said cylinder cluster in use, rotating with respect to said ported member about said rotary valve axis at a rotational rate indexed to the rate of rotation of the crankshaft with respect to the ported member by an indexing drive, said indexing drive controllable by a phase controlling differential input such that the angular phasing of the otherwise fixed ratio rotational indexing of the crankshaft and cylinder cluster rotation with respect to the ported member can be shifted to change fluid communication timing between the at least one inlet/outlet port of each cylinder and the ports of the ported member relative to the range of movement of the piston in each cylinder.

28. A machine as claimed in claim 27 wherein said indexing drive is comprised of an epicyclic gear set said epicyclic gear set including an externally toothed sun gear concentric to said crankshaft axis and either formed as part of or rigidly mounted to or off of said crankshaft that has gear teeth that engage directly or indirectly with the teeth of one or more externally toothed planet gears dependent directly or- indirectly from said ported member and said planet gears' teeth to also engage directly or indirectly with the teeth of an internally toothed annular gear either formed as part of, or mounted rigidly to said cylinder cluster or an extension thereof and concentric to said crankshaft axis.

29. A machine as claimed in claim 28 wherein said planet gear(s) is/are mounted by a planet gear carrier body.

30. A machine as claimed in claim 29 wherein said planet gear carrier body is mounted off of said ported member or an extension thereof by bearings and has an axis of rotation coaxial with said crankshaft axis permitting rotation of said planet gear carrier body with respect to said ported member about said crankshaft axis over a range to allow phase shift between the ported member and the cylinder cluster.

31. A machine as claimed in claim 30 wherein rotation of said planet gear carrier body allows the angular location of said ports of said ported member about said crankshaft axis with respect to the angular position of said cylinder cluster about said crankshaft axis at which said pistons reach TDC to be altered by rotation of said planet gear carrier with respect to said ported member to effectively advance or retard the port timing.

32. A machine as claimed in claim 30 wherein the rotation of said planet gear carrier with respect to said ported member acts as a differential input to said indexing drive allowing the angular phasing of the rotational indexing between said crankshaft and said cylinder cluster with respect to said ported member to be varied.

33. A machine as claimed in claim 27 wherein said indexing drive is comprised of an epicyclic gear set said epicyclic gear set including an externally toothed sun gear concentric to said crankshaft axis and either formed as part of or rigidly mounted to or off of said crankshaft that has gear teeth that engage directly or indirectly with the teeth of at least one of a first planet gear dependent from and rotatable mounted relative said ported member, a second planet gear rotationally constrained relative said first planetary gear and coaxially supported thereto and relative said ported member that includes gear teeth to engage directly or indirectly with the teeth of an internally toothed annular gear either formed as part of, or mounted rigidly to said cylinder cluster or an extension thereof and concentric to said crankshaft axis, where the gear teeth angle of said first planet gear is different to the gear teeth angle of the second planet gear, said phase controlling input can displace at least the planet gear with a gear teeth angle that is not parallel to its rotational axis in a direction along its rotational axis to thereby change fluid port timing. ■

34. A machine as claimed in any one of claims 27 to 33 wherein said machine is an internal combustion engine,, timing of ignition or fuel injection with respect to angle of crankshaft rotation at piston TDC can be altered appropriately by an electronic or mechanical control system to complement any changes in the port timing advance/retard.

35. An axial piston internal combustion engine comprising; a cylinder cluster of at least two cylinders rigidly located with respect to each other, each said cylinder including at least one fluid inlet and/or outlet .opening, in each cylinder, a complementary piston to reciprocate along a reciprocating axis defined by its respective cylinder, a crankshaft fotatable relative to said cylinder cluster about a crankshaft axis said crankshaft carrying a crank that has a crank axis passing through said crankshaft axis at an angle, a connecting mechanism linking said pistons within said respective cylinders to said crankshaft such that the rotational motion of the crankshaft with respect to the cylinder cluster drives the reciprocal motion of the pistons within their respective cylinders or visa versa, between top dead centre (TDC) and bottom dead centre (BDC) a ported member presented so that said inlet/outlet opening(s) of each cylinder can be sealed therewith and includes ports being comprised of a selection of at least one fuel injection port and/or at least one fuel ignition ports and/or at least one fluid inlet and/or outlet port, each of which said ports to come into cyclic communication with each cylinder in the cylinder cluster in turn to allow fuel ignition and/or .fluid transfer to and from said cylinders via said ports of said ported member timed to coincide with the desired range of movement of a piston in a cylinder between TDC and BDC, an indexing drive to transmit rotation between said cylinder cluster and said crank shaft to, in use, rotate said cylinder cluster relative said ported member about said crankshaft axis at a rotational rate indexed to the rate of rotation of the crankshaft thereby operatively presenting said inlet/outlet openings to each of said ports for cyclic communication with the inlet/ outlet openings of each cylinder in the cylinder cluster in turn, corresponding to the desired phase of motion of a said piston in its respective cylinder between its top dead centre and bottom dead centre positioning relative to its angular position about said crankshaft axis with respect to the ported member, an indexing drive phase controller to change the configuration of the indexing drive to thereby vary the angular phasing between the cylinder cluster and the ported member and thereby, for each cylinder, change the range of motion of the piston between top dead centre and bottom dead centre at which said inlet/outlet opening is in communication with the ports of the ported member.

36. An engine as claimed in claim 35 wherein said indexing drive is an epicyclic drive comprising of a sun gear engaged to the crankshaft and rotationally constrained thereto to rotate about the crank shaft axis, said sun gear coupled via at least one planetary gear to annular gear, one engaged to one of each of the cylinder cluster and ported member, said phase controller coupled to one of said planetary gear and said annular gear and said sun gear to cause it to be displaced to thereby cause a phase shift to occur.

37. In a Z-crank axial piston internal combustion engine that includes (i) a cylinder cluster of at least two piston containing cylinders rigidly located with respect to each other, each said cylinder including at least one working fluid transfer port (ϋ) a crankshaft rotatable relative to said cylinder cluster and carrying an angled crank about which a reciprocator can rotate that is in mechanical connection with the pistons and (ϋi) a ported member relative to which the cylinder cluster rotates and that can seal the at least one fluid transfer port of each cylinder yet offers, at intervals, their exposure to spark plug(s) and/or working fluid delivery and removal facilities, an indexing drive to transmit rotation between said cylinder cluster and said crank shaft to, in use, rotate said cylinder cluster relative said ported member about said crankshaft axis at a rotational rate timed to coincide with the desired range of movement of the piston in each cylinder between TDC and BDC, and an indexing drive phase controller to change the configuration of the indexing drive to thereby vary the angular phasing between the cylinder cluster and the ported member and thereby, for each cylinder, change the range of motion of the piston between top dead centre and bottom dead centre at which said at least one fluid transfer port is in communication with said facilities.

38. A Z-crank axial piston internal combustion engine comprising; a cylinder cluster of at least two piston containing cylinders rigidly located with respect to each other, each said cylinder including at least one working fluid transfer port, a crankshaft rotatable relative to said cylinder cluster and carrying an angled crank about which a reciprocator can rotate that is in mechanical connection with the pistons and a ported member relative to which the cylinder- cluster can rotate and that can seal the at least one fluid transfer port of each cylinder yet offers, at intervals, 'their exposure to spark plug(s) and/or working fluid delivery and removal facilities, an indexing drive to transmit rotation between said cylinder cluster and said crank shaft to, in use, rotate said cylinder cluster relative said ported member about said crankshaft axis at a rotational rate timed to coincide with the desired range of movement of the piston in each cylinder between TDC and BDC, and an indexing drive phase controller to change the configuration of the indexing drive to thereby vary the angular phasing between the cylinder cluster and the ported member and thereby, for each cylinder, change the range of motion of the piston between top dead centre and bottom dead centre at which said at least one fluid transfer port is in communication with said facilities.