MULTI-STATE DRIVETRAIN SYSTEM COMPREHENSIVE OF A SINGLE TORQUE MACHINE

Abstract

Powertrain system (20), comprising: an internal combustion engine (40) comprising a crank link (35); a torque machine (34) comprising a rotatable shaft element (33); and a transmission (50) comprising an input element (48) and an output element (62); wherein the crank link (35) of the internal combustion engine (40) can be coupled to the input element (48) of the transmission (50) via a first clutch (51); wherein the rotatable shaft element (33) of the torque machine (34) can be coupled to the crank link (35) of the internal combustion engine (40) via a pulley mechanism (36) and a second clutch (52) at a first transmission ratio; wherein the rotatable shaft element (33) of the torque machine (34) can be coupled to the input element (48) of the transmission (50) via a gear set (45) and a third clutch (53) at a second transmission ratio; characterized by the fact that the output element (62) is connected to at least one wheel (66) via a differential gear device (65) which is mechanically coupled to an axle (64) which is mechanically coupled to the at least one wheel (66); wherein the transmission (50) is designed as a manual transmission or as a continuously variable transmission (CVT) which can be operated in a variety of selectable fixed gear ratios; and where the first translation ratio is smaller than the second translation ratio.

Description

TECHNICAL AREA

[0001] The present invention relates to a powertrain system according to the preamble of claim 1, as is known essentially from US 2008 / 0236917 A1.

[0002] Regarding the further state of the art, reference is made at this point to publications US 8 974 337 B2 and EP 3 031 648 A1. BACKGROUND

[0003] Power transmission devices are used to transfer mechanical power between one or more drive motors and a final drive system. Common drive motors include internal combustion engines and non-combustion torque-generating machines. A final drive system may include a differential or other gearing, a belt or chain drive, or a fluid system that transmits mechanical power to perform work. When the power transmission device is used in a vehicle, the final drive system may include axles that transmit power to the vehicle's wheels for propulsion. SUMMARY

[0004] According to the invention, a drive train system is presented which is characterized by the features of claim 1.

[0005] The aforementioned features and advantages, as well as further features and advantages of the present teachings, will become clear from the following detailed description of some of the best embodiments and other ways of carrying out the present teachings with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The following describes one or more exemplary embodiments with reference to the accompanying drawings, in which: Fig. 1. Schematically selected elements of a first embodiment of a powertrain system comprising an internal combustion engine and a single non-combustion torque machine arranged to transmit torque through a transmission to a powertrain according to the disclosure, and Fig.2 schematically selected elements of another embodiment of a powertrain system comprising an internal combustion engine and a single non-combustion torque machine arranged to transmit torque through a transmission to a powertrain according to the disclosure. DETAILED DESCRIPTION

[0007] With reference to the drawings, in which the illustrations serve only to demonstrate certain exemplary embodiments, illustrates Fig.1. Schematically selected elements of a drivetrain system 20 coupled to a drivetrain 60 and controlled by a control system 10, wherein the drivetrain system 20 can advantageously be used on a vehicle 100 to generate drive torque in one of several operating states. The drivetrain system 60 may include a differential gear device 65 mechanically coupled to an axle 64, a transaxle, or a half-axle, which in one embodiment is mechanically coupled to a wheel / wheels 66. The drivetrain 60 transmits traction power between the transmission 50 and a road surface. Identical reference numerals throughout the description refer to identical elements. The drivetrain system 20 includes several torque-generating devices, including an internal combustion engine (motor) 40 and a single non-combustion torque machine, e.g.an electrically driven motor / generator (electric machine) 34. The motor 40 and the electric machine 34 are arranged to transmit mechanical power to the drivetrain 60 via a pulley mechanism 36 and / or a gear set 45 through a transmission 50. The concepts described herein can be applied to any suitable drivetrain configuration that includes the motor 40 and the single electric machine 34 arranged to generate torque that can be transmitted to the drivetrain 60 via the transmission 50. Embodiments of the vehicle 100 may, by means of non-limiting examples, include a passenger car, a light or heavy-duty vehicle, a commercial vehicle, an agricultural vehicle, an industrial / warehouse vehicle, a recreational off-road vehicle, or any other suitable vehicle.

[0008] The engine 40 is preferably a multi-cylinder internal combustion engine that converts fuel into mechanical torque via a thermodynamic combustion process. The engine 40 is equipped with several actuators and sensor devices for operational monitoring and for fuel supply to form cylinder-internal combustion charges to generate an expanding force, which is transmitted via pistons and connecting rods to the crankshaft 35 to generate torque. The engine 40 is preferably controlled by an engine control module (ECM) 44, which includes the control of engine operation in one or more different states, including an ON state, an OFF state, an all-cylinder state, a cylinder deactivation state, a fuel supply state, and a fuel cut-off state (FCO).The engine 40 is preferably mechanized with suitable hardware, and the ECM 44 preferably includes suitable executable routines for performing auto-start and auto-stop functions, fuel cut-off (FCO) functions, and cylinder deactivation functions during the operation of the powertrain system 20. The engine 40 is considered off when it is not rotating. The engine 40 is in the on state when it is rotating. This includes, among other things, one or more FCO states in which the engine 40 rotates without a fuel supply.The cylinder deactivation state involves engine operation in which one or more engine cylinders are operated in states where no fuel is supplied and no firing occurs, preferably with the engine exhaust valves in open states to minimize pumping losses, while remaining cylinders are supplied with fuel, fired, and generate torque. Engine mechanizations and control routines for performing auto-start, auto-stop, FCO, and cylinder deactivation routines are known and are not described here.

[0009] The transmission 50 can be a torque transmission device configured to automatically shift gears at predetermined speed / torque shift points. The transmission 50 is configured to operate in a variety of selectable fixed gear ratios, thereby achieving a preferred match between an operator's torque request and an engine operating point. It preferably employs one or a variety of differential gear sets and hydraulically actuated clutches to effect gear shifting, enabling torque transmission in one of the selectable fixed gear ratios over a range of speed ratios between the input element 48 and the output element 62. The transmission 50 can be controlled by means of a controllable hydraulic circuit communicating with a transmission control module (TCM).The 50 transmission performs upshifts to engage a fixed gear with a lower numerical multiplication ratio (gear ratio) and downshifts to engage a fixed gear with a higher numerical multiplication ratio. Upshifting may require a decrease in engine speed so that, at a given gear ratio, the engine speed matches the transmission output speed multiplied by the gear ratio. Downshifting may require an increase in engine speed so that, at a given gear ratio, the engine speed matches the transmission output speed multiplied by the gear ratio.Alternatively, the transmission 50 can be configured as a continuously variable transmission (CVT) using a belt and movable pulleys or another variable-ratio device and with similar hydraulic control of its stepless ratio. Alternatively, the transmission 50 can be configured as a manual transmission. The transmission 50 can include mechanisms for transmitting torque in gear states, which in one embodiment are associated with either a first, nominal forward direction or a second, nominal reverse direction between the input element 48 and the output element 62. Alternatively, the transmission 50 can include a simplified gear set arranged to transmit power in gear states such that the direction of rotation of the output element 62 is the same as the direction of rotation of the input element 48.However, the simplified gear set of the transmission 50 does not include a reversing mechanism and is therefore not intended for the transmission of power in a direction of rotation of the output element 62 that is opposite to the direction of rotation of the input element 48.

[0010] A high-voltage DC power source 25 is electrically connected to an inverter module 32 via a high-voltage DC bus 29 to transmit the high-voltage DC power via high-voltage conductors 31 to the electric machine 34 in response to control signals originating from the control system 10. The electric machine 34 is preferably a multi-phase electric motor / generator configured to convert stored electrical energy into mechanical power and the mechanical power into electrical energy that can be stored in the DC power source 25. The electric machine 34 preferably includes a rotor coupled to the rotatable element 33 and a stator and is electrically connected to the DC power source 25 via the inverter module 32 and the high-voltage bus 29. The inverter module 32 is equipped with suitable control circuitry, including power transistors, such as...The inverter module 32 uses IGBTs to convert high-voltage direct current (HVDC) to high-voltage alternating current (AC) and vice versa. It preferably employs pulse-width modulation (PWM) control of the IGBTs to convert stored DC electrical energy from the DC power source 25 into AC electrical energy to drive the electric machine 34 and generate torque. Similarly, the inverter module 32 converts mechanical power transferred to the electric machine 34 into DC electrical energy to generate electrical energy that can be stored in the DC power source 25, among other uses, as part of a regenerative control strategy. The inverter module 32 receives motor control commands and controls the inverter states to provide motor drive and regenerative braking functionality.In one embodiment, a DC / DC converter 23 establishes an electrical connection to the high-voltage bus 29 and supplies electrical current to a low-voltage battery 27 via a low-voltage bus 28. Such electrical power connections are known and are not described in detail here. By way of a non-limiting example, the low-voltage battery 27 has a nominal voltage level of 12 VDC. The low-voltage battery 27 establishes an electrical connection to an auxiliary power system to supply low-voltage current to low-voltage systems 26 on the vehicle, including, for example, lighting systems, power windows, HVAC fans, seats, and infotainment systems. The DC power source 25 can be any high-voltage energy storage device, i.e., a multi-cell lithium-ion device, an ultracapacitor, or another suitable device.Monitored parameters relating to the DC power source 25 preferably include a state of charge (SOC), temperature, and other conditions. In a non-limiting example, the DC power source 25 has a nominal voltage level of 48 VDC. In one embodiment, the DC power source 25 can be electrically connected to a remote electrical power source located outside the vehicle via a vehicle-integrated battery charger 24 while the vehicle is stationary.

[0011] The control system 10 includes a controller 12 that connects significantly to an operator interface 14 and preferably to a variety of human-machine interface devices. The human-machine interface devices include, for example, an accelerator pedal 15, a brake pedal 16, and a gear selector (PRNDL) 17. Other human-machine interface devices preferably include an ignition switch to allow an operator to start and operate the engine 40, a steering wheel, and a headlight switch. The accelerator pedal 15 provides a signal input indicating an accelerator pedal position, and the brake pedal 16 provides a signal input indicating a brake pedal position.The transmission range selection device 17 provides a signal input that specifies a direction of the movement of the vehicle intended by the operator, which includes, among other things, a discrete number of operator-selectable positions that specify a preferred direction of rotation of the output component 62 in either a forward or a reverse direction.

[0012] The terms controller, control module, module, control, control unit, processor and similar refer to one or more combinations of application-specific integrated circuit(s) (ASIC), electronic circuit(s), central processing unit(s), such as microprocessor(s) and associated non-volatile memory components in the form of memory and storage devices (read memory, programmable read memory, direct access, hard disk, etc.).

[0013] The non-volatile memory component is capable of storing machine-readable instructions in the form of one or more software or firmware programs or routines, combinational logic circuits, input / output circuits and devices, signal conditioning and buffer circuits, and other components that can be accessed by one or more processors to provide a described functionality. Input / output devices and circuits include analog-to-digital converters and similar devices that monitor sensor inputs at a predetermined polling frequency or in response to a trigger event. Software, firmware, programs, instructions, control routines, code, algorithms, and similar terms refer to all sets of instructions executable by a control unit, such as calibrations and value tables.Each control unit executes control routine(s) to provide the desired functions, including monitoring inputs from sensor devices and other networked control units, and also executes control and diagnostic routines to manage actuator operation. These routines can be executed at regular intervals, such as every 100 microseconds during operation. Alternatively, routines can be executed in response to a trigger event. Communication between control units, as well as between control units, actuators, and / or sensors, can be achieved via point-to-point direct cabling, a network communication bus connection, a wireless connection, or any other suitable communication link. This communication involves the exchange of data signals in any suitable manner, including, for example,Electrical signals travel through a conductive medium, electromagnetic signals through the air, optical signals via fiber optic cables, and so on. Data signals can include discrete analog or digitized analog signals representing sensor inputs and actuator commands, as well as communication signals between control units. The term "signal" refers to any physically perceptible indication that conveys information and can encompass any suitable waveform (e.g., electrical, optical, magnetic, mechanical, or electromagnetic), such as direct current, alternating current, sine waves, triangle waves, square waves, vibration, and the like, that can propagate through a medium.

[0014] The rotatable element 33, which is coupled to the rotor of the electric machine 32, is preferably rotatably mechanically coupled to the crankshaft 35 of the motor 40 via a second clutch 52 and a pulley mechanism 36. Preferably, the second clutch 52 rotatably couples the pulley mechanism 36 and the crankshaft 35 of the motor 40 when it is engaged. The rotatable element 33 of the electric machine 34 is rotatably coupled to the input element 48 of the transmission 50 via a third clutch 53 and a gear set 45. The pulley mechanism 36 is arranged to couple rotations of the electric machine 34 and the motor 40 with a first input / output gear ratio when the second clutch 52 is engaged.

[0015] The gear set 45 preferably includes a displacement gear mechanism with a first gear 46 meshing with a second gear 47, wherein the first gear 46 is connected to a rotatable element which, by activating the third clutch 53, is rotatably connected to the rotatable element 33 of the rotor of the electric machine 34. The second gear 47 can be connected to the crankshaft 35 of the motor 40 by activating a first clutch 51 and rotatably connected to the input element 48 of the transmission 50. The number of teeth of the first gear 46 and the second gear 47 are selected such that a second input / output gear ratio is achieved. The gear set 45 is arranged to couple rotations of the electric machine 34 and the input element 48 of the transmission 50 with the second input / output gear ratio.The first input / output ratio is significantly smaller than the second input / output ratio. By way of a non-limiting example, the first input / output ratio can be 2.5:1 and the second input / output ratio can be 10:1. Alternatively, the first input / output ratio can be 4:1 and the second input / output ratio can be 8:1. Alternatively, the first input / output ratio and the second input / output ratio can be any suitable values, with the second input / output ratio preferably being larger than the first input / output ratio. In one embodiment, an additional drive device 55 is rotatably connected to the pulley mechanism 36 via a fourth coupling 54.In one embodiment, the additional drive device 55 is an air conditioning compressor.

[0016] The pulley mechanism 36 is configured to transmit torque between the motor 40 and the electric machine 34, including transmitting torque from the electric machine 34 to the motor 40 for motor auto-start and auto-stop operations, traction torque support, torque transmission for regenerative braking of the vehicle, and transmitting torque from the motor 40 to the electric machine 34 for electric charging. The pulley mechanism 36 is also configured to transmit torque between the auxiliary drive device 55 and either the motor 40 or the electric machine 34.In one embodiment, the pulley mechanism 36 includes a serpentine belt 38 guided between a first pulley 39 rotatably coupled to the crankshaft 35 of the motor 40, a second pulley 37 attached to a rotating shaft that can be coupled to the rotor of the electric machine 34 via the second coupling 52, and a third pulley 56 rotatably coupled to the additional drive device 55. The effective diameters of the first pulley 39 and the second pulley 37 are selected to provide the first input / output transmission ratio. Alternatively, the pulley mechanism 36 can include a positive displacement mechanism or another suitable positive mechanical rotary connection between the motor 40 and the electric machine 34.As such, the electrically driven electric machine 34 can be used to rotate the motor 40 and vice versa. Furthermore, either the electric machine 34 or the motor 40 can be used to rotate the additional drive device 55. Other configurations of the multimode drive train system 20, which include the electric machine 34 rotatably mechanically coupled to the motor 40, can be employed.

[0017] If the transmission 50 includes a reverse gear, the pulley mechanism 36 and the gear set 45 preferably have either positive or negative gear ratios, meaning that they transmit the rotation between the crankshaft 35 and the rotatable element 33 of the electric machine 34 in the same direction. As such, the pulley mechanism 36 is configured to drive the first and second pulleys 37, 39 on opposite sides of the belt 38, or alternatively, the gear set 45 includes an intermediate gear (not shown) between the first gear 46 and the second gear 47.

[0018] The first clutch 51, the second clutch 52, the third clutch 53, and the fourth clutch 54 can be any suitable selectively activatable mechanical devices for transmitting rotatable mechanical power between a drive element and a driven element. This can include, by way of non-limiting examples, a friction clutch, a freewheel clutch, a selectable one-way clutch, or another suitable device. In one embodiment, the first clutch 51 is an operator-actuated clutch device when the transmission 50 is configured as a manually shifted transmission. Operator-actuated clutch devices and manually shifted transmissions are known to those skilled in the art.

[0019] Operating states for the powertrain system 20 described herein can include an electric vehicle (EV) state, a parallel hybrid (PH) state, an electrical power generation state, an engine start state, and a vehicle start / engine start state, each of which can be determined by activating and deactivating the first clutch 51, the second clutch 52, and the third clutch 53, respectively. The clutch activation for the various operating states is given with reference to Table 1, where 'X' represents full activation and 'S' represents partial activation (i.e., torque transmission during slippage) of the first clutch 51, the second clutch 52, and the third clutch 53 for this embodiment. Table 1 Powertrain condition First clutch 51 Second clutch 52 Third clutch 53 EV state X EV state, high ratio at engine start S X High pH ratio X X EV state, low ratio at engine start S X Low pH ratio X X Indirect pH state X X Engine only condition X Neutral charge and engine start condition X Neutral - state of the additional drive

[0020] In EV mode, the electric machine 34 generates a torque that is transmitted via the gear set 45 to the gearbox 50, with the third clutch 53 engaged. The motor 40 can be in OFF mode, in FCO mode, or idling. The fourth clutch 54 can be selectively engaged to actuate the auxiliary drive device 55.

[0021] The PH states include a low PH ratio state and a high PH ratio state. In each state, the motor 40 generates torque that is transmitted to the gearbox 50 via the activation of the first clutch 51. In the high PH ratio state, the electric machine 34 generates torque that is transmitted to the gearbox 50 via the gear set 45, with the third clutch 53 activated. In the low PH ratio state, the electric machine 34 generates torque that is transmitted to the gearbox 50 via the gear set 45, with the second clutch 52 activated. The fourth clutch 54 can be selectively activated to actuate the additional drive device 55.

[0022] In the indirect PH state, the second and third clutches 52 and 53 are engaged, and the engine power is transmitted to one or more vehicle wheels 66 solely through the pulley mechanism 36. This can be used if the operator does not engage an operator-controlled first clutch 51, provided the pulley mechanism 36 and the gear set 46 transmit rotation in the same direction. Alternatively, if the pulley mechanism 36 and the gear set 46 transmit rotation in opposite directions, the indirect PH state can be used to provide a reverse gear using the engine 40, and the transmission 50 may have a simplified design that does not include a reversing mechanism.As such, the gears of the transmission 50 are arranged to transmit power such that the direction of rotation of the output element 62 is the same as the direction of rotation of the input element 48. However, the gear set of the transmission 50 does not include a reversing mechanism and is therefore not intended to transmit power in a direction of rotation of the output element 62 that is opposite to the direction of rotation of the input element 48.

[0023] In the optional EV state with a low ratio at engine start, the second clutch 52 slips and the third clutch 53 is engaged. This requires the second clutch to be designed for slippage and additional torque from the electric motor 34 to start the engine 40 due to the low ratio. This state could be used to bypass other states if an operator suddenly commands maximum acceleration, quickly requiring high engine speed and PH operation. In the EV state with a high-ratio engine start, the first clutch 51 slips and the third clutch 53 is engaged. In the engine-only state, the engine 40 is coupled to the transmission 50 via the engagement of the first clutch 51 and is otherwise disengaged from the pulley mechanism 36 by the disengagement of the second clutch 52.The electric machine 34 is also decoupled from the provision of a drive torque by deactivating the third clutch 53.

[0024] In the electrical power generation state, the motor 40 generates a torque which is transmitted to the gearbox 50 via the activation of the first clutch 51, and transmits the torque via the pulley mechanism 36 and the second clutch 52 to the electric machine 34 for electrical power generation.

[0025] The engine can be started using the electric motor 34 to generate torque, which is transmitted via the pulley mechanism 36 and the second clutch 52 to rotate the engine 40 as part of a starting routine. The fourth clutch 54 can be selectively deactivated to prevent the additional drive device 55 from being operated during engine starting.

[0026] Neutral can be achieved by deactivating the first, second and third clutches 51, 52, 53, whereby during this operation the electric machine 34 is able to provide torque for additional drive purposes.

[0027] Such an arrangement facilitates the electrification of a powertrain system that uses a single, relatively small electric machine with a relatively low motor torque capacity. The high gear ratio between the electric machine and the transmission input allows for a low transmission input speed while driving in EV mode, minimizing clutch speed and power loss during engine start-up. Furthermore, a low gear ratio between the electric machine and the engine while operating with the engine in ON mode facilitates hybrid drive, such as in PH mode.

[0028] Fig.Figure 2 schematically shows selected elements of another embodiment of a drivetrain system 120, which can be coupled to a drivetrain 160 and is controlled by a control system 110, wherein the drivetrain system 120 can advantageously be used on a vehicle 200 to generate drive torque. The drivetrain system 120 includes several torque-generating devices, including a motor 140 and a single non-combustion torque machine, e.g., an electrically driven motor / generator (electric machine) 134. The motor 140 and the electric machine 134 are arranged to transmit torque via a gearbox 150, which is rotatably mounted on the drivetrain 160 to transmit torque between them.The drive system 160 can include a differential gear device mechanically coupled to one or more axles 164, a transaxle, or an axle shaft, which in one embodiment is mechanically coupled to a wheel 166. The drive train 160 transmits traction power between the transmission 150 and a road surface. The concepts described herein can be applied to any suitable drive train configuration that includes the motor 140 and the single electric machine 134 arranged to generate torque that can be transmitted to the drive train 160 via the transmission 150. The concepts described herein are analogous to those referred to in [reference to be added]. Fig. 1 described.

[0029] The drive train system 120 includes the motor 140 and the electric machine 134, which, as described herein, is arranged to transmit mechanical power to the gearbox 140. The motor 140 includes a crankshaft 135, which is rotatably coupled via a first clutch 151 to a first end 147 of an input element 148 of the gearbox 150. The electric machine 134 includes an output element 133, which is rotatably coupled to its rotor, and the output element 133 is rotatably coupled to a sun gear 172 of a compound planetary gear set 170. A second end 149 of the input element 148 of the gearbox 150 passes through the body of the gearbox 150 and is rotatably coupled to a carrier 176 of the compound planetary gear set 170.

[0030] The compound planetary gear set 170 includes the sun gear 172, a plurality of compound gear sets 173 rotatably coupled to the carrier 176, and first and second ring gears 178 and 180, respectively. Each compound gear set 173 includes a first gear set 174 rotatably coupled to a second gear set 175. The first gear set 174 meshes with the first ring gear 178, and the second gear set 175 meshes with the second ring gear 180. Preferably, the diameter and number of teeth of the first gear set 174 are larger than the diameter and number of teeth of the second gear set 175. A first controllable clutch brake (brake) 179 is coupled to the first ring gear 178 to ground its rotation when activated, and a second controllable clutch brake (brake) 181 is coupled to the second ring gear 180 to ground its rotation when activated.When the first brake 179 is activated, the compound planetary gear set 170 transmits mechanical power at a relatively lower gear ratio, e.g., a 4:1 gear ratio between the electric machine 134 and the input element 148. When the second brake 181 is activated, the compound planetary gear set 170 transmits mechanical power at a relatively higher gear ratio, e.g., an 8:1 gear ratio between the electric machine 134 and the input element 148. The lower and higher gear ratios can be any suitable ratios and refer to the diameter and number of teeth of the first gear set 174 in relation to the diameter and number of teeth of the second gear set 175.The first clutch 151 and the first and second brakes 179, 181 can be any suitable selectively actuated mechanical devices and can include, as non-limiting examples, a friction clutch, a one-way clutch, a selectable one-way clutch, or another suitable device. In one embodiment, the first clutch 151 is an operator-actuated clutch device when the transmission 150 is configured as a manually shifted transmission. Operator-actuated clutch devices and manually shifted transmissions are known to those skilled in the art.

[0031] Operating states for the powertrain system 120 described herein can include an electric vehicle (EV) state, a parallel hybrid (PH) state, an electrical power generation state, an engine start state, and a vehicle start / engine start state, each of which can be determined by activating and deactivating the first clutch 151 and the first and second brakes 179, 181. The clutch activation for the various operating states is given with reference to Table 2, where 'X' represents full activation and 'S' represents partial activation (i.e., torque transmission during slippage) of the first clutch 151 and the first and second brakes 179, 181 for this embodiment. Table 2 Powertrain condition First clutch 151 First brake 179 Second brake 181 High EV ratio X High EV ratio at engine start S X High pH ratio X X Low EV ratio X Low EV ratio condition at engine start S X Low pH ratio condition X X

[0032] In the EV states, the electric machine 134 is capable of generating torque that can be transmitted to the gearbox 150 via the compound planetary gear set 170, the first brake 179, and the second brake 181. The motor 140 can be in the OFF state, an FCO state, or idling. The PH states include a low PH ratio state and a high PH ratio state. In each of these states, the motor 140 is capable of generating torque that is transmitted to the gearbox 150 via the activation of the compound planetary gear set 170 and the first clutch 151. In the high PH ratio state, the second brake 181 is activated, and the electric machine 134 is capable of generating torque that is transmitted to the gearbox 150.In the low PH ratio state, the first brake 179 is activated, and the electric machine 134 is able to generate torque that is transmitted to the gearbox 150. The generated torque can also be transmitted via the compound planetary gear set 170, with the first brake 181 activated for electrical power generation to the electric machine 134. In the high EV ratio state with engine start, the electric machine 134 is able to generate torque that can be transmitted via the input element 148, the first clutch 151, and the second brake 181 to rotate the engine 140 as part of a start routine. In the low EV ratio state with engine start, the electric machine 134 is able to generate torque that can be transmitted via the input element 148, the first clutch 151, and the first brake 179 to rotate the engine 140 as part of a start routine.

[0033] Such an arrangement facilitates the electrification of a powertrain system that uses a single, relatively small electric machine with a relatively low motor torque capacity. The high gear ratio between the electric machine and the transmission input allows for a low transmission input speed while driving in EV mode, minimizing clutch speed and power loss during engine start-up. Furthermore, a low gear ratio between the electric machine and the engine while operating with the engine in ON mode facilitates hybrid drive, such as in PH mode.

[0034] The ones relating to the Fig. 1 and Fig.The two illustrated embodiments facilitate vehicle operation, with the engine normally remaining at low or medium speeds. Such vehicle operation includes starting the vehicle from a standstill in EV mode, transitioning from EV mode to engine start-up using the high EV ratio with the engine start-up state, stationary operation in the high PH ratio state, and regenerative braking in EV mode.

Claims

[1] Powertrain system (20) comprising: an internal combustion engine (40) having a crank member (35); a torque machine (34) having a rotatable shaft member (33); and a transmission (50) having an input member (48) and an output member (62); wherein the crank member (35) of the internal combustion engine (40) can be coupled to the input element (48) of the transmission (50) via a first clutch (51); wherein the rotatable shaft element (33) of the torque machine (34) is coupleable to the crank member (35) of the internal combustion engine (40) via a pulley mechanism (36) and a second clutch (52) at a first gear ratio; wherein the rotatable shaft element (33) of the torque machine (34) is coupleable to the input element (48) of the transmission (50) via a gear set (45) and a third clutch (53) at a second gear ratio; characterized by, that the output element (62) is drivingly connected to at least one wheel (66) via a differential gear device (65) which is mechanically coupled to an axle (64) which is mechanically coupled to the at least one wheel (66); wherein the transmission (50) is designed as a manual transmission or as a continuously variable transmission (CVT) operable in a plurality of selectable fixed gear ratios; and where the first gear ratio is smaller than the second gear ratio. [2] The powertrain system (20) of claim 1, wherein the pulley mechanism (36) includes a first pulley (39) rotatably coupled to the crank member (35) of the internal combustion engine (40) and a second pulley (37) rotatably coupled to the rotatable shaft member (33) of the torque machine (34) via the second clutch, the effective diameter of the first pulley (39) and the second pulley (37) being selected to effect the first input / output gear ratio. [3] The powertrain system (20) of claim 1, wherein the powertrain system (20) is operable to transmit the power from the internal combustion engine (40) to the transmission (50) via the pulley mechanism by the activation of the second clutch (52) and the third clutch (53). [4] The powertrain system (20) of claim 1, wherein the pulley mechanism (36) is arranged to transmit mechanical power to the input member (48) of the transmission (50) in a first rotational direction, and wherein the gear set (45) is arranged to transmit mechanical power to the input member (48) of the transmission (50) in a second rotational direction opposite to the first rotational direction. [5] The powertrain system (20) of claim 4, wherein the transmission (50) is arranged to operate in a reverse direction by activating the second clutch (52) and the third clutch (53). [6] The powertrain system (20) of claim 4, wherein the transmission (50) is arranged to transmit power such that a direction of rotation of the output member (62) is the same as the direction of rotation of the input member (48) of the transmission (50), and wherein the transmission (50) is not arranged to transmit power in a direction of rotation of the output member (62) that is opposite to the direction of rotation of the input member (48) of the transmission (50). [7] The powertrain system (20) of claim 1, wherein the gear set (45) includes a first gear (46) rotatably coupled to the rotatable shaft member (33) of the torque machine (34) via the third clutch (53), and wherein the tooth numbers of the first gear and a second gear (47) are selected to effect the second input / output gear ratio. [8] The powertrain system (20) of claim 1, wherein the powertrain system (20) is operated in an electric vehicle state when only the third clutch (53) is activated. [9] The powertrain system (20) of claim 1, wherein the first gear ratio is 4:1 and the second gear ratio is 8:1.

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