Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines
  • B60K6/08—Prime-movers comprising combustion engines and mechanical or fluid energy storing means
  • B60K6/10—Prime-movers comprising combustion engines and mechanical or fluid energy storing means by means of a chargeable mechanical accumulator, e.g. flywheel
  • B60K6/105—Prime-movers comprising combustion engines and mechanical or fluid energy storing means by means of a chargeable mechanical accumulator, e.g. flywheel the accumulator being a flywheel
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines
  • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
  • B60K6/42—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs characterised by the architecture of the hybrid electric vehicle
  • B60K6/44—Series-parallel type
  • B60K6/445—Differential gearing distribution type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K6/00—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines
  • B60K6/20—Arrangement or mounting of plural diverse prime-movers for mutual or common propulsion, e.g. hybrid propulsion systems comprising electric motors and internal combustion engines the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
  • B60K6/50—Architecture of the driveline characterised by arrangement or kind of transmission units
  • B60K6/54—Transmission for changing ratio
  • B60K6/543—Transmission for changing ratio the transmission being a continuously variable transmission
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
  • F16H37/02—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00 comprising essentially only toothed or friction gearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16H—GEARING
  • F16H15/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by friction between rotary members
  • F16H15/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by friction between rotary members without members having orbital motion
  • F16H15/04—Gearings providing a continuous range of gear ratios
  • F16H15/06—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B
  • F16H15/32—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B in which the member B has a curved friction surface formed as a surface of a body of revolution generated by a curve which is neither a circular arc centered on its axis of revolution nor a straight line
  • F16H15/36—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B in which the member B has a curved friction surface formed as a surface of a body of revolution generated by a curve which is neither a circular arc centered on its axis of revolution nor a straight line with concave friction surface, e.g. a hollow toroid surface
  • F16H15/38—Gearings providing a continuous range of gear ratios in which a member A of uniform effective diameter mounted on a shaft may co-operate with different parts of a member B in which the member B has a curved friction surface formed as a surface of a body of revolution generated by a curve which is neither a circular arc centered on its axis of revolution nor a straight line with concave friction surface, e.g. a hollow toroid surface with two members B having hollow toroid surfaces opposite to each other, the member or members A being adjustably mounted between the surfaces
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/60—Other road transportation technologies with climate change mitigation effect
  • Y02T10/62—Hybrid vehicles

Definitions

• This invention relates to transmission systems, particularly but not exclusively to vehicle transmission systems. Another aspect of the present invention relates to a vehicle incorporating such a transmission system. A novel variator that can be employed in the transmission system herein disclosed is also described.
• Electric hybrid powertrains using electrochemical batteries, power electronics and motor-generators have previously been proposed, but such arrangements tend to be relatively expensive compared to traditional internal combustion engine powertrains. It is also the case that inefficiencies associated with the multiple conversions of energy into different forms that take place in such systems (particularly during regenerative braking) reduces the net amount of energy that can be saved with such a system as compared with a conventional vehicle. It is also the case that electric systems are typically relatively heavy and therefore extra energy is spent transporting this extra mass. Even though fully-electric vehicles will have zero "at the wheel” emissions, it is the case that manufacturing and subsequent end-of-life processing of electrochemical batteries for this application has significant environmental impact. In the light of this, it would be beneficial to provide hybrid systems that reduce the total energy consumption and emissions, that are fully- recyclable and that come at a price point that is affordable for manufacturer and customer alike. Previously proposed electric hybrids do not (at present) meet all of these criteria.
• flywheel As a kinetic energy storage device to provide a mechanical alternative to electrical systems.
• Previously proposed high-speed flywheel hybrid systems (such as those of Flybrid Automotive Ltd) generally have a higher power-to-weight ratio than equivalent electric hybrid systems and are able to capture and return more of a vehicle's kinetic energy when performing regenerative braking. This is mostly because energy form conversions are avoided, especially during regenerative braking; kinetic energy is simply transferred from one inertia to another (the vehicle and the energy storage flywheel).
• Mechanical transmissions are usually recyclable since they are constructed almost entirely from steel and aluminium (apart from the seals and lubricants and a carbon fibre wrap for the high-speed flywheel). The abundance of these materials means that the cost of the raw material is relatively low, and mass-manufacturing techniques allow relatively low-cost manufacture.
• flywheel hybrid systems such as those of Flybrid Automotive Ltd are designed to interface with conventional vehicle architecture, comprising a clutch, discrete gearbox and differential. This is to provide a low-cost system that can be readily accepted by vehicle manufacturers mindful of financial risk, since it does not fundamentally change the layout and overall concept of the vehicle.
• Flybrid Automotive Ltd's current advertised systems are able to accomplish regenerative braking, function in engine stop-start mode (e.g. in a mode wherethe engine can be turned off while waiting at traffic lights) and drive the vehicle under flywheel power alone.
• the flywheel can be used to allow the engine to operate in a more efficient regime than is normally possible with a discrete gearbox transmission alone.
• a presently preferred implementation of the teachings of the invention provides a transmission system, comprising first and second variators; first, second and third source/sink couplings; and reconfigurable mechanical linkage coupling the first and second variators to the first, second and third source/sink couplings; wherein the mechanical linkage is configurable for power transfer between at least two of said source/sink couplings via one of said first and second variators or via both of said first and second variators.
• the mechanical linkage is configurable for simultaneous power transfer via both of said first and second variators.
• power transfer via both of said variators can occur without power transfer though one said variator followed by the other said variator.
• one or both of said variators may be torque controlled. In another arrangement, one or both of said variators may be ratio controlled.
• said variators may have the same torque/power capacity. In another implementation, said variators may be of different torque/power capacity.
• said first source/sink coupling is connectable to a prime mover
• said second source/sink coupling is connectable to a vehicle drive
• said third source/sink coupling is connectable to a secondary mover
• the prime mover may comprise an engine (for example, an internal combustion engine) and said secondary mover may comprise an energy storage unit.
• the energy storage unit may comprise a flywheel.
• the energy storage unit may comprise a store for electrical power and an electric motor-generator.
• the store for electrical power may comprise one or more electrochemical batteries or a capacitor or bank of capacitors.
• the mechanical linkage may be configurable to enable power transfer from said prime mover to said secondary mover via one of said variators.
• the mechanical linkage may be configurable to enable power transfer from said vehicle drive to said secondary mover via one of said variators.
• the mechanical linkage may be configurable to enable power transfer from said secondary mover to said vehicle drive via one or both of said variators.
• the mechanical linkage may be configurable to enable power transfer from said prime mover to said vehicle drive via one of or both of said variators.
• the mechanical linkage may be configurable to enable power transfer from said prime mover to said vehicle drive via one of said variators, and power transfer from said prime mover to said secondary mover via the other of said variators.
• the mechanical linkage may be configurable to enable power transfer from said prime mover to said vehicle drive via one of said variators, and to enable power transfer from said secondary mover to said vehicle drive via the other of said variators.
• the mechanical linkage may be configurable to enable power transfer from said prime mover to said secondary mover via one of said variators, and to enable power transfer from said vehicle drive to said secondary mover via the other of said variators.
• the transmission system may comprise a fourth sink/source coupling.
• the fourth sink/source coupling may be connectable to a second vehicle drive.
• the mechanical linkage may be selectively configurable to provide power transfer from said prime mover and/or said secondary mover to said vehicle drive and/or said secondary vehicle drive.
• the mechanical linkage may be selectively configurable to provide power transfer from said prime mover to one of said vehicle drive or said second vehicle drive, and to provide power transfer from second secondary mover to the other of said vehicle drive or said second vehicle drive.
• the mechanical linkage includes a plurality of clutches.
• a transmission system for a vehicle comprising first and second variators arranged in parallel with one another.
• Another arrangement implementing the teachings of the invention provides a vehicle comprising a transmission system as herein described, a prime mover connectable to said first sink/source coupling, and a secondary mover connectable to said third sink/source coupling.
• One illustrative implementation of the teachings of this invention provides a mechanical CVT for the engine (or other prime mover) as well as a mechanical CVT for controlling energy storage and recovery of a flywheel (or other energy storage device).
• One illustrative advantage of the arrangements disclosed herein is that power flow in any particular transmission configuration only passes through one traction drive (CVT), rather than through two traction drives in series, thereby substantially increasing mechanical efficiency.
• Another illustrative advantage of the mechanical CVTs disclosed herein - as compared with electric CVT systems - is that energy form conversions are avoided; once fuel has been converted into mechanical energy at the engine crank (or energy stored in an electrochemical battery has been converted into mechanical energy at the motor-generator shaft), it remains in this state throughout the transmission. Additionally, the mechanical systems proposed herein will likely be less expensive and more recyclable than their electric alternatives.
• teachings of the invention provide a continuously variable transmission that includes any combination of features disclosed in this application alone, or in combination with any features disclosed in the aforementioned priority application or the accompanying supplement.
• a variator for such a transmission a propulsion system for a vehicle that includes such a transmission
• a propulsion system for a vehicle that includes such a transmission
• a propulsion system for a vehicle that includes such a transmission
• Fig. 1 is a schematic representation of an illustrative multi-input variator
• Fig. 2 is a three-dimensional cut-away view of the variator depicted in Fig. 1 ;
• Fig. 3 is a schematic representation of a transmission employing a variator of the type depicted in Figs. 1 and 2;
• Fig. 3 is a schematic representation of another transmission that employs a variator of the type depicted in Figs. 1 and 2;
• Figs. 5(a) to 5(c) are illustrative transmission arrangements that implement the teachings of the invention, and which may (but do not have to) employ the variator of Figs. 1 and 2;
• Fig. 6 is a schematic representation of another transmission arrangement that implements the teachings of the invention.
• Figs. 7(a) to 7(k) are schematic representations of different operating modes for the transmission arrangement depicted in Fig. 6;
• Fig. 8 is a schematic representation of another transmission arrangement that implements the teachings of the invention.
• Multi-Continuouslv Variable Planetary (MCVP) hybrid transmission CVT/IVT
• the arrangement depicted in Fig. 1 employs a novel multiple-input variator with two independent ratio control mechanisms.
• the variator is a planetary transmission with multiple planets that are double conical surfaces whose rotational axes are inclined relative to the main variator rotational axis - in a preferred arrangement at an angle equal to the half cone angle, as shown in Fig. 2.
• This arrangement provides two surfaces that are parallel to the main axis.
• Axial shifting of a central disc 20 along the inside surface provides a sun branch with variable speed ratio to control the flywheel; and axial shifting of an outer annulus along the outside surface provides a branch with IVT functionality for example for the vehicle final drive.
• Fig. 2 is a possible layout of the MCVP configured as in Fig. 1 where the constant annulus branch is fixed to ground.
• the final drive of the vehicle is connected to the variable annulus shaft, which gives IVT potential (including reverse, with the bias of the ratio spread being chosen to suit the application by suitable design selection of the MCVP radii shown in Fig. 1).
• the MCVP shown in Error! Reference source not found uses planets where the cones face base to base on the planet shaft.
• the two cones may also be arranged such that they may face tip to tip or in the same direction.
• the former arrangement would allow the diameter of the constant annulus to be reduced (which reduces the rotational stresses for the same shaft angular speed), the latter would mean that either both of the sun branches or both of the annuli branches would be variable.
• Planets may be inclined at an angle that is deliberately greater or smaller than the half cone angle so that an increasing interference as the contact disc/annulus moves in a direction of increasing (steady state) torque (i.e. reduction in speed output shaft speed, and hence increase in torque for the same power).
• This is a passive system; meaning it does not require any external control.
• Another passive method would be elastically straining the disc/annulus that make traction contact with the conical planets, where this strain creates further interference and hence generates normal pressure on the fluid which increases with applied torque.
• the system may be bi-directional so that two similar mechanisms are used to act in opposite directions to create pressure from reversing torque. There would be backlash in this system as one mechanism relaxes whilst the other tenses when the direction of torque reverses.
• a prime mover is connected to the constant sun shaft 1 , to which is attached a bevel gear 2 (the constant sun gear) which meshes with a set of planet bevel gears 3 which are located in this embodiment at the axial centre of the planet 4 (one for each planet). Also on each planet 4 is another bevel gear 5 which meshes with an internal bevel gear 6, which is the constant annulus shaft (non- rotational in this embodiment since this branch is fixed to the casing 7).
• the bevel gears on the planets can be positioned in various places along the planet axis, such as between the cones 8 as shown or either side to achieve the same functionality and that the choice will ultimately be made by the constraints of the assembly.
• the planets are supported in a planet carrier 9 using bearings 10, said carrier being free to rotate in thisarrangement, but may be used as an input/output shaft in anotherarrangement.
• variable sun shaft 11 which is supported by bearings 12,13 in the carrier 9 and constant sun shaft 1 respectively.
• the constant sun shaft 1 may be supported by bearings 14 in the carrier 9 which is in turn supported by bearings 15 in the hollow variable annulus shaft 16.
• the variable annulus shaft 16 is geared to the final drive of the vehicle.
• the variable annulus shaft 16 is supported by bearings 17 in the casing 7.
• a beneficial feature of this arrangement is that all input/output shafts and the carrier rotate in the same direction, and so the bearings only run at the difference between the shaft speeds. A consequence of this is that the speed rating requirement for the bearings is not especially high despite the fact that the shafts may be running at high speed (absolute). This reduces the machining precision required for these bearings and hence the cost.
• variable annulus shaft 16 requires a mechanism allowing axial shifting of the annulus 19 making traction contact with the planet cone 7 in order to change the speed ratio between the prime mover and the vehicle.
• variable sun shaft 11 also requires a mechanism to axially shift the variable sun disc 20 in order to change the speed of the flywheel relative to the prime mover/vehicle.
• These two variable branches may utilise methods employed in the so-called "Turbo Trac" variator (see patent nos. US6001042 & US7856902) to facilitate this ratio control.
• the bevel gears 2,3,5,6 may be spiral bevel gears to reduce noise and vibration and provide smooth torque transfer and increased fatigue life for the gear teeth and surfaces.
• Klingelnberg spiral bevel gears (where the teeth are not tapered) in particular may be used which can be generated with a hobbing process much like automotive gearboxes and hence benefit from low cost in volume production despite their seemingly complex geometry.
• Palloid tooth form may also be produced by hobbing but has greater bending strength since the teeth are tapered.
• All of the bevel gears mentioned (2,3,5,6) may also be replaced by traction- drive surfaces (sometimes referred to as friction gears).
• variable annulus shaft 16 is hollow, allowing the constant sun shaft 1 to pass through coaxially on the same side of the MCVP 28, being connected to the prime mover 29 via a gearbox 30 and a clutch 31.
• This arrangement conveniently allows the differential 32 to be placed in the middle of the vehicle's powered axle, between the prime mover 29 and the MCVP 28, since this is permitted by the relative sizing of the prime mover, MCVP and flywheel.
• the prime mover 29, gearbox 30 and clutch 31 may be a standard automotive or motorbike engine and gearbox arrangement 34 with the included clutch 31.
• the flywheel 33 is connected to the variable sun shaft 11 via a clutch 35 and a gear box 36; order of said clutch and gearbox in the torque path is chosen for ease of component design/selection.
• Said gearbox 36 may be a single fixed ratio, or a plurality of selectable ratios in order to behave as a ratio range extender for the flywheel branch of the MCVP, which can be appreciated by those skilled in the art.
• Said range extender may have capability to change gear without torque interruption (such as, but not limited to, dual- or multiple-clutch gearboxes) so as to allow continuous charging and discharging of the flywheel over a large range of vehicle/prime mover speeds.
• flywheel gearbox does reverse the direction of rotation, then this can be counteracted by first ensuring the flywheel is in the correct orientation to rotate oppositely to the wheels, then selecting a gearing arrangement that will ensure the correct direction of shaft rotation at the vehicle wheels, whilst ensuring the drive from the prime mover is also in the correct rotational direction.
• Mechanical brakes 38 can bring the vehicle safely to rest in event of failure of any control critical components in the transmission.
• the flywheel and prime mover clutches 35,31 are simply disengaged in order to stop supply of power to the vehicle.
• the MCVP described above is a dual ratio-controlled planetary variator that can also operate in a (quasi-)torque-controlled mode.
• This mode is achieved by virtue of its similarities with the conventional planetary gear set (comprising a sun gear and shaft, an annulus internal gear and shaft, both of said gears mesh with a set of planet gears located in the planet gear carrier connected to a carrier shaft), which is known to be used as a torque-splitting device in transmissions.
• the conventional planetary gear set comprising a sun gear and shaft, an annulus internal gear and shaft, both of said gears mesh with a set of planet gears located in the planet gear carrier connected to a carrier shaft
• the conventional planetary gear set comprising a sun gear and shaft, an annulus internal gear and shaft, both of said gears mesh with a set of planet gears located in the planet gear carrier connected to a carrier shaft
• the conventional planetary gear set comprising a sun gear and shaft, an annulus internal gear and shaft, both of said gears mesh
• three branches of the MCVP are used: the carrier, one of the annuli/rings and one of the suns. These three branches make up a conventional planetary arrangement, but here the planetary (or epicyclic) ratio is continuously variable.
• the flywheel, the prime mover and the vehicle final drive are each connected to a different branch. Clutches are used to vary which of the branches the prime mover, flywheel and vehicle are connected to, depending on the mode of operation.
• Actuation of one (or both) of the ratio control mechanisms can change the planetary ratio and thus adjust the torque split.
• Each branch will accelerate depending on the torque applied to it (whilst obeying the linear speed relationship), thus facilitating torque control.
• the transmission system is controlled by controlling the engine torque in conjunction with the planetary ratio, in response to driver inputs or road conditions. In this mode, the vehicle speed depends on both the engine and flywheel speeds.
• any planetary variator may be employed to form this torque-controlled transmission (including but not limited to the NuVinci CVP, the Kopp variator and the Milner CVT).
• An advantage of using the MCVP of this arrangement as compared with the other variators is that a given planetary ratio can be achieved in a variety of actuator positions (if both ratio control mechanisms are changed simultaneously).
• This embodiment of the teachings of the invention makes use of two CVTs and a set of clutches that change the positions of these CVTs within the transmission to provide the arrangements depicted in Figs. 5(a) to 5(c), for example.
• power flow only passes through one CVT in all modes of operation (rather than two in series) and thereby provide relatively high transmission efficiency.
• the following embodiments provide a torque-controlled transmission.
• Fig. 5(a) power is supplied to the wheels of the vehicle (in this particular example) from both the prime mover (for example an internal combustion engine) and an energy storage unit, such as a flywheel.
• the prime mover drives the vehicle wheels, and excess power passes to the energy storage unit.
• power from the vehicle wheels for example, from regenerative braking
• power from the prime mover pass to the energy storage unit.
• the benefits of the previously proposed Torotrak toroidal variator are principally that it has high power density and that it is torque-controlled (unlike other CVTs, which are ratio-controlled).
• the former means it is a relatively compact and low mass system.
• the latter means that the desired torque to be applied is signalled by hydraulic pressure at the roller pistons and reaction torques are exerted either side of the variator; causing the ratio of the variator to change automatically.
• direct control of torque allows effective management of the power flow arrangements depicted in Fig.
• Ratio-controlled variators in contrast, have to calculate and control the precise ratio (and rate of change of ratio) in order to exert the correct torque on the flywheel, prime mover and final drive.
• the disclosed arrangements can be implemented with a ratio-controlled variator, but there will be higher parasitic losses and control will be more complex.
• a prime mover 100 is connected to a first variator 101 via a clutch 102.
• a gear 103 can be rotationally coupled to the input shaft 104 to the first variator 101 via a clutch 105.
• Said gear 103 is in mesh with a gear 106 rotationally coupled to the output of a second variator 107.
• Another gear 108 can also be rotationally coupled to said input shaft 104 by another clutch 109.
• Said gear 108 is in mesh with idler gear 123.
• Said idler gear is in mesh with another gear 110.
• Said gear 110 is rotationally coupled to the input of said second variator 107.
• Said input of said second variator 107 is also rotationally coupled to the vehicle final drive 111 via a clutch 112.
• Between said clutch 112 and said final drive 111 is another gear 113 which can be rotationally coupled to said clutch 112 and said final drive 111 via a clutch 114.
• Said gear 113 is in mesh with another gear 115 which is rotationally coupled to the output of said first variator 101.
• Said gear 113 is also in mesh with another gear 1 16.
• Said gear 116 can be rotationally coupled to a shaft 117 via a clutch 118.
• Another gear 119 can be rotationally coupled to said shaft 117 via another clutch 120.
• Said gear 119 is in mesh with an idler gear 121.
• Said idler gear 121 is also in mesh with said gear 106, rotationally coupled to the said output of the second variator 107.
• An energy storage flywheel unit 122 is rotationally coupled to said shaft 1 17.
• Said flywheel unit 122 may also include step-up gearing to enable the use of a high-speed flywheel. Such step-up gearing may be traction drive technology.
• a flywheel is merely one type of energy storage unit that may be employed in this and other embodiments.
• Other types of energy storage unit known to persons skilled in the art may instead be employed.
• one or more electrochemical batteries (or a capacitor or bank of capacitors) connected to an electric motor-generator would serve the same purpose as a flywheel.
• the flywheel 122 can be charged by the prime mover 100 whilst the vehicle is stationary (or not being powered) via the first variator 101 when clutches 105,109,112,114,120 are open and clutches 102,118 are closed.
• the flywheel 122 can also be charged by the prime mover 100 whilst the vehicle is stationary (or not being powered) via the second variator 107 when clutches 105,1 12,114,118 are open and clutches 102,109,120 are closed.
• the flywheel 122 can also be charged by the prime mover 100 whilst the vehicle is stationary (or not being powered) via both the first and the second variators 101 ,107 when clutches 105,1 12,114 are open and clutches 102,109,1 18,120 are closed.
• the vehicle final drive 111 can be powered by discharging the flywheel 122, via either the first variator 101 or the second variator 107 or via both said variators 101 ,107 simultaneously.
• clutches 102,105,114,120 are open and clutches 109,112,118 are closed
• the flywheel can be discharged via the first variator 101.
• clutches 102,105,109,114,118 are open and clutches 1 12,120 are closed
• the flywheel can be discharged via the second variator 107.
• clutches 102,105,109,114,1 18 are open and clutches 109,1 12,118,120 are closed, the flywheel can be discharged via both the first and second variators 101 , 107.
• the vehicle final drive 111 can be powered by the prime mover alone through either or both of the variators 101 ,107.
• the flywheel 122 can be disconnected from the transmission by opening clutches 118,120.
• clutches 102,114 are closed and the remaining clutches 105,109,1 12,118,120 are open, then the prime mover 100 is transmitting power to the vehicle final drive 111 via the first variator 101.
• clutches 102,105,112 are closed and the remaining clutches 109,114,118,120 are open
• the prime mover 100 is transmitting power to the vehicle final drive 111 via the second variator 107.
• clutches 102,105,112,114 are closed and the remaining clutches 109,118,120 are open, then the prime mover 100 is transmitting power to the vehicle final drive 111 via both the first and second variators 101 ,107.
• the prime mover 100 may supply more power than the vehicle needs at any instant in time.
• the flywheel 122 can be charged with this excess power via the first variator 101 whilst required prime mover power is transmitted to the final drive 111 via the second variator 107.
• This is mode can occur when clutches 102,105,112,118 are closed and clutches 109,114,120 are open.
• the flywheel 122 can be charged with excess prime mover power via the second variator 107 whilst the required prime mover power is transmitted to the final drive 111 via the first variator 101.
• This mode can occur when clutches 102,109,1 14,120 are closed and clutches 105,112,118 are open.
• the prime mover 100 may supply less power than the vehicle needs at any instant in time.
• the flywheel 122 in order to provide the shortfall in power, the flywheel 122 can be discharged via the second variator 107 whilst prime mover power is transmitted to the final drive 1 11 via the first variator 101.
• This mode can occur when clutches 102,112,114,120 are closed and clutches 105,109,118 are open.
• the vehicle final drive 1 1 1 can be retarded by charging the flywheel 122, via either the first variator 101 or the second variator 107 or via both said variators 101 ,107 simultaneously.
• clutches 102,105,114,120 are open and clutches 109,112,118 are closed
• the flywheel can be charged via the first variator 101.
• clutches 102,105,109,114,1 18 are open and clutches 112,120 are closed
• the flywheel can be charged via the second variator 107.
• clutches 102,105,109,114,118 are open and clutches 109,112,1 18,120 are closed, the flywheel can be charged via both the first and second variators 101 ,107.
• Figs. 7(a) to 7(k) the transmission depicted in Fig. 6 can provide the following operating modes:
• This arrangement provides for vehicle kinetic energy to be taken from both front and rear axles simultaneously, allowing 100% of the braking force to be provided by the mechanical KERS, thus being able to capture more energy that would normally be wasted.
• the appropriate braking proportion can be applied to each axle by controlling the torque exerted by each torque-controlled variator.
• Both variators serve to accelerate the single flywheel, and the torque control feature means that both variator ratios adjust themselves automatically. If ratio-controlled variators were used, this would be much more difficult to control in synchrony.
• the two variators 101 ,107 are able to serve the function of a conventional differential in 4WD vehicles that connects the differentials on the front and rear axles; however the mechanical efficiency will likely be higher (for example, similar to a conventional continuously variable transmission passing only through one differential).
• Previously proposed high-speed flywheel mechanical hybrid transmissions do not provide a means for four wheel drive kinetic energy recovery, partly due to the lower "round-trip" efficiency normally associated with passing through two bevel-geared differentials in series.
• either variator can be chosen to transmit the power to the vehicle (when using one source of motive power, be it prime mover or flywheel), the two variators can have different torque capacity. At very low power requirement, power can be transmitted through a smaller variator; at medium power requirement, power can be transmitted through a larger variator; at high power requirement, power can be transmitted through both larger and smaller variators simultaneously. This increases system efficiency and effectiveness. This applies to both driving (under flywheel or prime mover power, either in isolation or both combined) and regenerative braking using the flywheel. When the flywheel is accepting surplus engine torque (or supplementing insufficient engine torque), the power flow through the variator to the flywheel may well be low and so a lower torque capacity variator facilitates higher transmission efficiency.
• Each final drive 125,126 can be connected to the flywheel with a different variator 101 ,107.
• the clutch arrangements are the same for driving and braking under flywheel power alone. Controlling the torque in each variator provides control of brake balance front to rear during regenerative braking.
• first final drive 126 is connected to the flywheel via the first variator 101 and the second final drive 125 is connected to the flywheel via the second variator 107, then clutches 102,109,112,118 are open and clutches 105,114,120,124 are closed.
• the prime mover 100 can be connected to the first final drive 126 via the first variator 101 and to the second final drive 125 via the second variator 107.
• the two variators provide the differential function between the two final drives 126,125. This mode of operation is achieved when clutches 109,112,118,120 are and open and clutches 102,105,114,124 are closed.
• the prime mover 100 may supply more power than the vehicle needs at any instant in time.
• the flywheel 122 can be charged with this excess power via the first variator 101 whilst required prime mover power is transmitted to either (or both) final drive(s) 126,125 via the second variator 107.
• This is mode can occur when clutches 102,105,118 are closed, clutches 109,114,120 are open, and at least one of clutches 112,124 are closed. Clutch 112 allows drive to the first final drive 126 and clutch 124 allows drive to the second final drive 125.
• the prime mover 100 can power the first final drive 126 via the first variator 101. Clutches 102,114 are closed and clutches 105,109,118 are all open.
• the flywheel 122 can power the second final drive 125 via the second variator 107 when clutches 120,124 are closed and clutch 112 is open.
• the flywheel 122 can also power the first final drive 126 when clutches 112,120 are closed and clutch 124 is open.
• both final drives can be rigidly locked together by closing clutches 112,120,124, allowing both the prime mover 100 and the flywheel 122 to power the vehicle together.
• the prime mover 100 charges the flywheel via the first variator 101 and one of the final drives provides a source of kinetic energy to be recovered via the flywheel 122 and second variator 107. This requires clutches 102,1 18,120 to be closed and clutches 105,109,114 to be open. If regenerative braking is to be carried out at the first final drive 126, then clutch 112 must also be closed. If regenerative braking is to be carried out at the second final drive then clutch 124 must also be closed.
• protection is claimed for the use of two variators to mediate power flow between a prime mover, a flywheel (or other energy storage device) and one or more driven axles, where clutches engage and disengage to provide various different modes of operation wherein power flow avoids passing through two variators in series (thereby avoiding loss of efficiency). Protection is also claimed for arrangements particularly (but not exclusively) when these variators are torque-controlled rather than ratio-controlled. Protection is also claimed for using two variators of different torque/power capacity.
• This invention relates to transmission systems, particularly but not exclusively to transmission systems for vehicles. Another aspect of the invention relates to a variator for such a transmission system.
• a further concern is that the amount and nature of engine emissions tend to vary considerably over the range of operating conditions experienced by the engine. Larger trucks, buses, lorries and off-highway vehicles tend to have larger diesel engines that typically produce peak emissions when under transient operating conditions, and as a consequence the performance of new engines of this type tends to be compromised in the design stage in order to meet increasingly stringent emissions regulations.
• the engine can also be switched off when the vehicle is temporarily stationary (for example, at traffic lights) - responsive vehicle behaviour when pulling away from standstill being provided by the motor-generators.
• series hybrids of the type described above generally do not add power capability, they can improve efficiency (under the right conditions).
• series hybrids tend to be expensive to produce due to the significant added cost of the electric motors and batteries, and the additional weight that such devices add to a typical vehicle also impacts upon performance and efficiency.
• the batteries themselves are also an environmental concern and are costly even in mass production, due to the materials and processes required in manufacture.
• Another important drawback of such systems is that power flow through the powertrain requires multiple energy conversions (between chemical, potential, mechanical, kinetic and electrical forms) and resultant energy losses.
• a further proposal is the so-called mechanical hybrid, such as those incorporating lightweight high-speed flywheels (such as those by Hybrid Systems, see www.flvbrid.co.uk ' ).
• the Hybrid systems are effectively "bolt on” devices that provide for kinetic energy recovery (regenerative braking), and are designed to interface with conventional powertrain architecture that comprises a clutch, a discrete gearbox and a differential.
• the hybrid component of the Flybrid system comprises a flywheel, a fixed gear stage, a clutch and a continuously variable transmission (CVT).
• Hybrid Systems have also demonstrated a so-called clutched flywheel transmission (CFT) that comprises two sets of three constantly meshed gears and a clutch per pair of gears (one designated from each set), and which uses controlled clutch slip to move between the fixed ratios.
• CFT clutched flywheel transmission
• This CFT system behaves in a similar way to the aforementioned CVT system but is less expensive to produce and more suitable for low power applications.
• Both of the aforementioned systems are so-called “parallel hybrid” systems that are capable of propelling the vehicle by means of a prime mover (such as an internal combustion engine) or the flywheel or a combination of both.
• the aforementioned systems also have "full hybrid” capability in that they can accept a proportion of surplus SUPPLEMENT 22
• a variator (otherwise referred to as an MCVP) comprising a first and a second cone, said cones being rotatable about a common axis that is inclined relative to a main axis so that said first and second cones each provide a side that is substantially parallel to said main axis.
• Protection is also claimed for a cone substantially as herein described, an MCVP as herein described, a vehicle transmission, and a vehicle incorporating an MCVP.
• Fig. 1 is a schematic representation of two truncated cones arranged along a common axis in a first configuration
• Fig. 2 is a schematic representation of alternative cone configurations
• Fig. 3 is another schematic representation of another cone configuration
• Fig. 4 is a schematic planetary analogy of an illustrative variator
• Fig. 5 is a schematic representation of an illustrative vehicle transmission
• Fig. 6 is a schematic representation of an arrangement that is functionally equivalent to the arrangement depicted in Fig. 5;
• Figs. 7(a) to 7(h) are schematic representations of several possible power paths.
• Fig. 8 is a schematic representation of an illustrative variator configuration
• Fig. 9 is a cut-away schematic representation of the variator depicted in Fig. 8; SUPPLEMENT 23
• Fig. 10 is a diagrammatic representation of a transmission system that incorporates the variator depicted in Figs. 8 or 9;
• Fig. 11 is a rendered image of the variator depicted in Figs. 8 and 9 in use with a prime mover and a flywheel.
• the system disclosed herein entirely replaces a conventional stepped (discrete gearbox) transmission.
• the system disclosed herein embodies the benefits of both series and parallel hybrid powertrains, in particular: increased power capability beyond that of the prime mover alone (parallel hybrid), and permitting the engine to operate entirely independently of the instantaneous vehicle requirements and thus achieve greater efficiency (series hybrid).
• the transmission system disclosed herein is used in conjunction with a prime mover (for example an internal combustion (IC) engine) and a flywheel.
• a prime mover for example an internal combustion (IC) engine
• a flywheel can be used to supply kinetic energy whilst also simultaneously accepting power from the prime.
• the flywheel thus acts as a buffer by being able to accept surplus engine power (even during regenerative braking) and by being able to supply extra power to the vehicle when needed, thus aiding engine downsizing.
• the system disclosed provides numerous additional useful modes of operation that are beneficial in a wide variety of ground vehicle applications.
• the system provides infinitely variable transmission (IVT) functionality (with reverse gear) for the final drive, with the flywheel being able to be charged with the prime mover power even whilst the wheels are in a powered neutral mode (where this energy is normally wasted as heat in power recirculation). It is also possible to start the engine with the flywheel if desired.
• IVTT infinitely variable transmission
• control strategies are also possible, which can be optimised for energy efficiency.
• CVT continuously variable transmission
• the ability to actuate two distinct mechanisms as provided in the system disclosed herein is equivalent to having two independent CVTs within one component, allowing the ability to independently choose an appropriate speed ratio for two different means of propelling a vehicle. This is useful in a multitude of applications, but is especially important for flywheel hybrids.
• the speed of the flywheel inherently changes during energy transfer (control of the flywheel speed controls the energy storage and recovery), since for a given flywheel inertia, the energy stored is purely a function of rotational speed; thus independent control of flywheel speed from the engine and the wheels is important.
• the novel CVT described herein may be referred to as a Multi- Continuously Variable Planetary (or CVP) due to its similarities to a planetary gear set and the aforementioned NuVinci CVP.
• the MCVP differs, however, from the NuVinci CVP by having more than one actuation mechanism. Providing more than one actuation SUPPLEMENT 25
• the MCVP disclosed herein provides significantly higher transmission efficiencies than two CVTs in which some power paths involve crossing two CVTs (equating to 4 traction contacts in series).
• traction contacts in parallel add linearly to the torque capacity of a CVT, but traction contacts in series reduce efficiency With a multiplicative relationship.
• the MCVP benefits from both of these facts. There is also the benefit of reduced mass and component count (and hence cost) owing to the same components contributing to both CVT mechanisms.
• the transmissions disclosed herein are not limited to use in vehicles.
• the transmissions disclosed herein are not limited to vehicles or machinery where the primary source of power is an internal combustion engine.
• most motor devices whether combustion engines, electric machines, hydraulic motors etc have regimes of operation where they are most efficient, and benefit from the properties gained from using the system disclosed herein.
• the term "prime mover" is used here to not restrict the invention to IC engines, since the system is equally suited to any motor device.
• the MCVP disclosed herein comprises a novel planetary traction drive (depicted schematically in Fig. 1 below) that employs planets which are double truncated cones inclined at an angle to the main shaft axis that is equal to half of the cone angle, thereby producing two effective straight edges aligned parallel to the main axis.
• Two independent actuator mechanisms control the axial position of a disc and a ring (green contact patches) that make contact with the inner and outer effective edges of the planet, which changes the contact radius on the planet and thus the linear speed, thereby changing the rotational speed of the said disc and ring.
• the ring and the disc rotate about the main rotational axis.
• One other "disc” and one other “ring” also make contact and provide a means of clamping the planet on all sides and a means for supplying pressure (for example, hydraulic/sprung etc) to induce elasto-hyrdrodynamic conditions in the contact fluid for efficient torque transfer.
• the planets themselves are mounted via bearings seated on the cylindrical parts of the truncated cones into a carrier which can also rotate about the main axis.
• the red contact points which are constrained from moving axially can be replaced with toothed gears (depicted schematically in Fig. 3 below) in between the two cones in order to increase mechanical efficiency (although SUPPLEMENT 26
• the abovedeseribed MCVP may be employed in a vehicle transmission that couples two at least two sources of motive power to one or more driven elements (such as a pair of wheels on an axle).
• Fig. 5 below is a schematic representation of one such SUPPLEMENT 28
• MCVP MCVP
• first and second sources of motive power in this illustrative example, a flywheel (labelled “FW”); a prime mover (labelled “PM”) such as, inter alia, a combustion engine, an electric machine or a hydraulic machine)), and a differential (labelled "Diff”) that is coupled to a pair of driven wheels on a braked axle.
• FW flywheel
• PM prime mover
• Diff differential
• the flywheel is connected to the variable "sun" branch of the MCVP
• the prime mover is connected to the constant "sun” branch
• the final drive is connected to the variable "ring” branch
• the constant ring branch is fixed to ground (no rotation).
• the carrier is necessarily free to rotate.
• the flywheel and the prime mover are connected to their respective branches by means of a clutch (as shown) and a fixed ratio gear stage (not shown) may also be provided before or after the clutch in order to be at the right speed in the transmission.
• the prime mover can be switched on and the prime mover clutch can be engaged and fully closed which causes the constant sun branch to rotate and also defines the speed of the carrier branch, since the constant ring branch is fixed to ground.
• the prime mover clutch can be engaged and fully closed which causes the constant sun branch to rotate and also defines the speed of the carrier branch, since the constant ring branch is fixed to ground.
• variable planet gear in contact/mesh with the variable speed output ring When the diameter of the variable planet gear in contact/mesh with the variable speed output ring is the same as the diameter of the constant planet gear in contact/mesh with the grounded ring, the final drive is in a powered neutral condition.
• the prime mover is rotating and supplying power, but the final drive is locked stationary.
• IVT Intelligent Variable Transmission
• any external torque exerted at the vehicle wheels will not cause the vehicle to move, such as in the case of being stationary on an inclined surface. Additionally, this means there is no need for a pulling- away clutch, reducing the number of components required.
• the final drive direction of rotation reverses either side of the powered neutral condition, providing the means for a reverse gear.
• the ratio spread either side of powered neutral can be adjusted to favour forward motion if desired by changing the diameter of the constant ring and planet gears.
• a key function offered in this mode is that other branches of the system remain rotational, and actuation of the other ratio control mechanism provides continued functionality for that respective branch independent of the powered neutral condition of the final drive. This allows the flywheel to be charged with the engine power by actuating the other ratio mechanism so as to increase the flywheel speed.
• the flywheel can conveniently continue to subtract torque to prevent this from happening (traction control system increases flywheel torque if wheels begin to slip) .
• both variator mechanisms require actuation, in order to slow down the final drive and simultaneously speed up the flywheel.
• Fig. 6 The arrangement shown schematically in Fig. 6 is functionally equivalent to the arrangement depicted in Fig. 5, and from this it is perhaps easier to visualise how simultaneous regenerative braking and engine charging of the flywheel is possible.
• Fig. 6 also shows two variators (the CVT and IVT) in the box that represents the MCVP in preferred configuration. If, instead of the aforementioned MCVP, two separate CVTs were used, a regenerative braking path would have to cross two CVTs per one way trip, and as such "round trip" power would have to cross four CVTs - an arrangement that is not particularly efficient. The arrangement described herein only effectively crosses one CVT per one-way trip (hence only two per round trip) and as a consequence is more efficient.
• the MVCP disclosed in the application has several operating modes, and schematic representations of the respective power paths SUPPLEMENT 31
• Fig. 9 is an illustration of a variator configured as shown schematically in Fig. 8 where the constant annulus branch is fixed to ground.
• the final drive of the vehicle is connected to the variable annulus shaft, which gives IVT potential (including reverse, with the bias of the ratio spread being chosen to suit the application by suitable design selection of the variator radii shown in Figure 8).
• the particur implementation shown in Figure 9 employs planets where the cones face base to base on the planet shaft.
• the two cones may, in another envisaged implementation, be arranged such that they may face tip to tip or in the same direction.
• the former arrangement would allow the diameter of the constant annulus to be reduced (which reduces the rotational stresses for the same shaft angular speed), the latter would mean that either both of the sun branches or both of the annuli branches would be variable.
• Planets may be inclined at an angle that is deliberately greater or smaller than the half cone angle so that an increasing interference as the contact disc/annulus moves in a direction of increasing (steady state) torque (i.e. SUPPLEMENT 42
• This is a passive system, meaning it does not require any external control.
• Another passive method would be elastically straining the disc/annulus that make traction contact with the conical planets, where this strain creates further interference and hence generates normal pressure on the fluid which increases wit applied torque.
• the system may be bi-directional so that two similar mechanisms are used to act in opposite directions to create pressure from reversing torque. There would be backlash in this system as one mechanism relaxes whilst the other tenses when the direction of torque reverses.
• the prime mover is connected to the constant sun shaft 1 , to which is attached a bevel gear 2 (the constant sun gear) which meshes with a set of planet bevel gears 3 which are located in this embodiment at the axial centre of the planet 4 (one for each planet). Also on each planet 4 is another bevel gear 5 which meshes with an internal bevel gear 6, which is the constant annulus shaft (non-rotational in this embodiment since this branch is fixed to the casing 7). It will be appreciated by those experienced in the art that the bevel gears on the planets can be positioned in various places along the planet axis, such as between the cones 8 as shown or either side to achieve the same functionality and that the choice will ultimately be made by the constraints of the assembly.
• the planets are supported in a planet carrier 9 using bearings 10. The carrier is free to rotate in this particular implementation, but may be used as an input/output shaft in other implementations.
• variable sun shaft 11 which is supported by bearings 12, 13 in the carrier 9 and constant sun shaft 1 respectively.
• the constant sun shaft 1 may be supported by bearings 4 in the carrier 9 which is in turn supported by bearings 15 in the hollow variable annulu shaft 16.
• the variable annulus shaft 16 is geared to the final drive of the vehicle.
• the variable annulus shaft 16 is supported by bearings 17 in the casing 7.
• variable annulus shaft 16 requires a mechanism allowing axial shifting of the annulus 19 making traction contact with the planet cone 7 in order to change the speed ratio between the prime mover and the vehicle.
• the variable sun shaft 11 also requires a mechanism to axially shift the variable sun disc 20 in order to change the speed of the SUPPLEMENT 43
• variable branches may utilise techniques such as those employed in the Turbo Trac variator (see patent nos. US6001042 & US7856902) to facilitate this ratio control.
• the bevel gears 2, 3, 5 and 6 may be spiral bevel gears to reduce noise and vibration and provide smooth torque transfer and increased fatigue life for the gear teeth and surfaces.
• Klingelnberg spiral bevel gears (where the teeth are not tapered) in particular may be used which can be generated with a nobbing process much like automotive gearboxes and hence benefit from low cost in volume production despite their seemingly complex geometry.
• Palloid tooth form may also be produced by nobbing but has greater bending strength since the teeth are tapered.
• Figure 10 is a schematic representation of a transmission that incorporates the variator of Figs. 8 and 9.
• the variable annulus shaft 16 is hollow, allowing the constant sun shaft 1 to pass through coaxially on the same side of the variator 28, being connected to the prime mover 29 via a gearbox 30 and a clutch 31.
• This arrangement conveniently allows the differential 32 to be placed in the middle of the vehicle's powered axle, between the prime mover 29 and the variator 28, since this is permitted by the relative sizing of the prime mover, variator and flywheel.
• the prime mover 29, gearbox 30 and clutch 31 may be a standard automotive or motorbike engine and gearbox arrangement 34 with the included clutch 31.
• the flywheel 33 is connected to the variable sun shaft 11 via a clutch 35 and a gear box 36; order of said clutch and gearbox in the torque path is chosen for ease of component design/selection.
• the gearbox 36 may be a single fixed ratio, or a plurality of selectable ratios in order to behave as a ratio range extender for the flywheel branch of the variator, which can be appreciated by those skilled in the art.
• the range extender may have the capability to change gear without torque interruption (such as, but not limited to, dual or multiple clutch gearboxes) so as to allow continuous charging and discharging of the flywheel over a large range of vehicle/prime mover speeds.
• Mechanical brakes 37 can bring the vehicle safely to rest in event of failure of any control critical components in the transmission.
• the flywheel and prime mover clutches 35, 31 are simply disengaged in order to stop supply of power to the vehicle.
• Fig. 1 1 is a schematic representation of a variator of the type disclosed herein mated with a 4-stroke 250CC prime mover and a flywheel.
• Mass savings may be made by effectively providing two CVTs in one assembly with common components shared between them.
• Planetary gear set similarities provide improved functionality as compared to existing planetary multiple input CVTs by adding at least one extra "branch” (5 in total), with two suns and two rings. Providing two similar type of branches e.g. suns is very useful and provides an improved choice of ratios and configurations (even in conventional one input / one output form) and by having independent ratio control.
• IVT powered neutral possible with other shafts than engine remaining active and other ratio mechanism operational, so another component can be powered or a flywheel charged rather than wasting energy in power recirculation.
• Figure 1 Drive cycle of an endurance lap shewing cumulative braking
• the NuVinci CVP typically has a ratio
• Figure 2 shows the energy saving on the endurance
• the NuVinci CVP has two effective annuli branches, a packaging of the vehicle. sun and a planet carrier.
• the system uses a high-speed
• flywheel connected to the vehicle transmission via a
• CVT full-toroidal variator
• MULTIPLE-INPUT PLANETARY VARIATORS vehicle must be connected to a vehicle final drive.
• the ilner CVT changes the ratio between all branches.
• variable gear radii shown in Figures 3 and 4 all of the variable gear radii shown in Figures 3 and 4 all of the variable gear radii shown in Figures 3 and 4 all of the variable gear radii shown in Figures 3 and 4 all of the variable gear radii shown in Figures 3 and 4 all of the variable gear radii shown in Figures 3 and 4 all of the variable gear radii shown in Figures 3 and 4 all of the variable gear radii shown in Figures 3 and 4 all
• the MCVP is a new planetary traction drive using R, a I Planet, ⁇ ⁇
• Ra Ra reference shall be made to this figure in explaining how the proposed system is able to accomplish simultaneous
• s, e o ow ng ene s are us ga ne y e such that the vehicle speed reduces, the kinetic energy SUPPLEMENT and momentum are exchanged between the vehicle and A scaling analysis of the variator is currently being the flywheel. If the engine is also supplying torque undertaken to assess what the optimum design (positive) and the CVT ratio is changed such that this parameters are for a given application. More detailed torque is also consumed by the changing the flywheel dynamic simulation is intended along with accurate speed, then the flywheel is being used to accept the mathematical models for the elasto-hydrodynamic (EHL) vehicle kinetic energy and the engine power at the same loss mechanisms within the variator.
• EHL elasto-hydrodynamic
• the system behaves like an electric series hybrid, in that
• the System Comprising a Flywheel and CVT for flywheel can accept surplus engine torque to prevent the Motorsport and Mainstream Automotive wheels from slipping at low speed (Figure A3).
• the system can be melted down and the
• Figure A1 Conventional geared-neutral mode (power recirculated & dissipated as heat) SUPPLEMENT
• Fi ure A2 Charging of flywheel in geared-neutral mode
• Figure A3 Surplus prime mover power (including traction-limited acceleration)

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• 2012
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