Hybrid drivetrain system

Abstract

Powertrain system (100), comprising: an internal combustion engine (10) which includes a crankshaft (12); an electric machine (30) comprising a rotatable shaft (32) coupled to a motor pulley (34); and a torque converter (50) comprising an impeller (58) and a pump (56) coupled to an external drive disc (52); wherein the outer drive pulley (52) of the torque converter (50) is rotatably coupled to the motor pulley (34) of the electric machine (30); wherein the electric machine (30) is coupled to the pump (56) of the torque converter (50) via the off-axis mechanical drive system (40); and wherein the crankshaft (12) is coupled to the pump (56) of the torque converter (50) via a clutch (24); characterized by the fact that the coupling (24) is a selectable one-way coupling; and that the outer drive disc (52) is arranged on an outer circumference of the pump (56).

Description

[0001] The present invention relates to a drive train system according to the preamble of claim 1, as is essentially known from DE 11 2010 005 953 T5 or JP 2012 - 35 680 A, wherein in the latter document, however, the motor pulley is not a belt pulley.

[0002] With regard to the further state of the art, reference is made to the documents DE 42 25 315 A1 and WO 2016 / 006 325 A1. BACKGROUND

[0003] Common hybrid powertrain systems include internal combustion engines and electric motor / generators coupled to transmissions to transfer torque to a final drive for motive power. Common electric motor / generators are supplied with electrical power by energy storage systems. Powertrain systems can operate in various modes to generate and transfer motive power to the vehicle's wheels. SUMMARY

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

[0005] Another aspect of the invention includes a starter rotatably coupled to the crankshaft.

[0006] Another aspect of the invention includes the electric machine electrically coupled to an inverter electrically connected to a source of electrical power, wherein the source of electrical power is configured to operate at a voltage level lower than 60 V DC.

[0007] Another aspect of the invention includes the outer drive pulley of the torque converter, which is rotatably coupled to the motor pulley of the electric machine via a continuous belt.

[0008] Another aspect of the invention includes the outer drive pulley of the torque converter, which is rotatably coupled to the motor pulley of the electric machine via a chain.

[0009] Another aspect of the invention includes the outer drive pulley of the torque converter, which is rotatably coupled to the motor pulley of the electric machine via intermeshing gears.

[0010] Another aspect of the invention includes a transmission including an input member and an output member, and a driveline, wherein the input member of the transmission is coupled to the impeller of the torque converter and the output member of the transmission is coupled to the driveline.

[0011] Another aspect of the invention includes a controller operatively connected to the powertrain system, the controller including a set of instructions executable to automatically stop the internal combustion engine and control operation of the powertrain system in an all-electric drive mode to transfer drive power to the driveline.

[0012] Another aspect of the invention includes a controller operatively connected to the powertrain system, the controller including a set of instructions executable to control operation of the powertrain system in an electric-assist motor drive mode to transfer drive power to the driveline.

[0013] Another aspect of the invention includes a controller operatively connected to the powertrain system, the controller including a set of instructions executable to control operation of the powertrain system in a regenerative mode to transfer drive power to the driveline.

[0014] Another aspect of the invention includes a controller operatively connected to the powertrain system, the controller including a set of instructions executable to control operation of the powertrain system in a motor-only drive mode to transfer drive power to the driveline.

[0015] Another aspect of the invention includes the internal combustion engine, the transmission and the final drive arranged in a front-wheel drive embodiment of a vehicle.

[0016] Another aspect of the invention includes the internal combustion engine, transmission, and final drive arranged in a rear-wheel drive embodiment of a vehicle.

[0017] The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of some of the best modes and other embodiments for carrying out the present teachings as defined in the appended claims, when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 schematically illustrates a powertrain system including an internal combustion engine having a crankshaft coupled to a transmission via a torque converter and coupled to an electrically driven torque machine via an off-axis mechanical drive system, the transmission coupling to a driveline, in accordance with the invention; Fig. 2 schematically illustrates a partial side sectional view of a portion of a powertrain system including a torque converter and an off-axis mechanical drive system coupled to an electrically driven torque machine, in accordance with the invention; Fig. 3 schematically illustrates an isometric view of a portion of an embodiment of an off-axis mechanical drive system coupled to an electrically driven torque machine that is part of a powertrain system, according to the invention; and Fig. 4 schematically illustrates an isometric view of a portion of another embodiment of an off-axis mechanical drive system coupled to an electrically driven torque machine that is part of a powertrain system, according to the invention. DETAILED DESCRIPTION

[0019] The components of the disclosed embodiments as described and illustrated herein can be arranged and designed in a variety of different configurations. Accordingly, the following detailed description is only representative of possible embodiments of the invention. Moreover, while numerous specific details are set forth in the following description in order to provide a thorough understanding of the embodiments disclosed herein, some embodiments may be practiced without some of these details. Moreover, for the sake of clarity, certain technical material known in the art has not been described in detail to avoid unnecessarily obscuring the invention.

[0020] Referring now to the drawings, which are for the sole purpose of illustrating certain exemplary embodiments, Fig. 1 schematically illustrates an embodiment of a hybrid powertrain system 100 comprising a plurality of torque-generating devices including an internal combustion engine (motor) 10 and at least one electrically driven torque machine (electric machine) 30. The motor 10 and the electric machine 30 are mechanically coupled via a torque converter 50 and an off-axis mechanical drive system 40 to transmit drive power to vehicle wheels 96 via a transmission 60 and a driveline 90. The concepts described herein may apply to any suitable powertrain configuration including the internal combustion engine 10 and the electric machine 30 coupled via the torque converter 50 and the off-axis mechanical drive system 40. Like reference numerals refer to like elements throughout the specification.Operation of the powertrain system 100 may be controlled by a controller 15, which is depicted as a unitary device for ease of illustration. The powertrain system 100 may advantageously be used on a vehicle to provide motive power, and the vehicle may include, by way of non-limiting examples, a passenger car, a light or heavy truck, a commercial vehicle, an agricultural vehicle, an industrial / warehouse vehicle, or a recreational off-road vehicle.

[0021] The powertrain system 100 is configured such that the engine 10 and the electric machine 30 mechanically couple to the transmission 60 using the torque converter 50 and the off-axis mechanical drive system 40. This allows the powertrain system 100 to be embodied in a front-wheel drive arrangement and operate in one of several selectable modes, including a motor-only drive mode, a pure electric drive mode, a regenerative braking mode, and a motor-electric assist mode. Alternatively, the powertrain system 100 may be embodied in a rear-wheel drive arrangement or an all-wheel drive arrangement and operable in one of several selectable modes, including a motor-only drive mode, a pure electric drive mode, a regenerative braking mode, and a motor-electric assist mode.The design of the powertrain system 100 enables engine stop / start operations during operation of the powertrain system. The powertrain system 100 described herein advantageously utilizes the torque converter 50, resulting in improved drivability during acceleration events, transmission shift events, and deceleration events. Furthermore, the off-axis mechanical drive system 40 is preferably configured to rotate the electric machine 30 at the engine speed, thereby eliminating the need for a generator to accomplish charging of a low-voltage battery 78. Further, there is no need for an additional electrically driven hydraulic pump for the transmission 60 because the electric machine 30 is configured and can be controlled to rotate the torque converter 50 when the engine 10 is in an OFF state.Furthermore, the engine disconnect clutch 24 may be integrated into the housing of the torque converter 50, thus facilitating regenerative braking and coasting mode operations, enabling pure electric propulsion mode operation, and enhancing closed throttle sailing.

[0022] The engine 10 is preferably embodied as a multi-cylinder internal combustion engine that converts fuel into mechanical torque through a thermodynamic combustion process. The engine 10 is equipped with a plurality of actuators and sensing devices for monitoring operation and delivering fuel to form charges for combustion in the cylinder, generating an expansive force on pistons, such force being transmitted to a crankshaft 12 to generate torque. The engine 10 includes a starter 20 including a starter switch and a starter gear 22, the starter gear 22 meshing with gear teeth disposed on an outer periphery of a flywheel 14 coupled to the crankshaft 12.The starter 20 is preferably embodied as a single-phase electric motor having an output shaft that couples to the starter gear 22, which is electrically connected to the low-voltage battery 78 via activation of the starter switch. In one embodiment, the starter gear 22 is continuously meshed with the flywheel 14. The flywheel 14 also couples to an input member 18, which is coupled to a pump portion 56 of the torque converter 50 via an engine disconnect clutch 24. In one embodiment, the engine disconnect clutch 24 is a selectable one-way clutch. The actuators of the engine 10, including the starter switch, are preferably controlled by an engine controller.

[0023] The engine 10 is preferably mechanically implemented with suitable hardware, and the engine controller preferably includes suitable control routines to perform auto-start and auto-stop functions, fuel supply and cut-off (FCO) functions, and all-cylinder and cylinder-deactivation functions during ongoing operation of the powertrain 100. The engine 10 shall be considered to be in an OFF state when it is not rotating. The engine 10 shall be considered to be in an ON state when it is rotating. The all-cylinder state includes engine operation in which all engine cylinders are activated by being supplied with fuel and ignited.The cylinder deactivation state includes engine operation in which one or a plurality of the engine cylinders are deactivated by not being fueled and not being fired, and preferably operating with engine exhaust valves in open states to minimize pumping losses while the remaining cylinders are fueled and fired, thus generating torque. The ON state may include the FCO state, in which the engine 10 is rapidly rotating and not being fueled. The ON state may include the cylinder deactivation state. The ON state may include the FCO state in combination with the cylinder deactivation state. Mechanical implementations of the engine and control routines for executing auto-start, auto-stop, FCO, and cylinder deactivation control routines are known and are not described herein.Engine operation can be described in the context of engine states, including an engine operating state, an engine fueling state, and an engine cylinder state. The engine operating states preferably include the ON and OFF states. The engine fueling states include the fueled state and the FCO state. The engine cylinder states include the all-cylinder states and the cylinder deactivation state.

[0024] The electric machine 30 is preferably a multi-phase electric motor / generator configured to convert stored electrical energy into mechanical power and convert mechanical power into electrical energy that can be stored in a DC power source (48V battery) 70. The 48V battery 70 is preferably configured at a nominal 48V DC voltage level. The electric machine 30 preferably includes a rotor and a stator and electrically connects to the 48V battery 70 via the inverter module 36. The rotor couples to a rotatable member 32, which couples to a motor pulley 34, which is an element of the off-axis mechanical drive system 40. Alternatively, another non-combustion torque machine, such as a pneumatically driven device or a hydraulically driven device, may be used in place of the electric machine 30.By definition, a non-combustion torque machine is any device capable of generating torque by converting a source of potential energy into kinetic energy without combustion of the potential energy. Non-limiting examples of potential energy sources include electrical energy, pneumatic energy, and hydraulic energy. Pneumatically driven devices and hydraulically driven devices are known and are not described in detail herein.

[0025] The torque converter 50 is a rotatable torque-coupling device disposed between the input member 18 of the engine 10 and an input member 51 of the transmission 60. The torque converter 50 preferably includes a pump 56 rotatably coupled to the crankshaft 12, a starter 57, an impeller 58 rotatably coupled to the input member 51 of the transmission 60, and a controllable clutch 59. The torque converter 50 operates to provide a fluid torque coupling between the pump 56 and the impeller 58 when the clutch 59 is deactivated or released, and provides a mechanical torque coupling between the pump 56 and the impeller 58 when the clutch 59 is activated. Other details relating to torque converter and torque converter clutch design are known and will not be described in detail herein.The pump 56 is coupled to an outer drive sheave 52 disposed on an outer periphery of the pump 56. An exemplary embodiment of a portion of the powertrain system 100 including the torque converter 50 and the outer drive sheave 52 is described with reference to FIG. Fig. 2. Alternatively, the outer drive sheave 52 may be mounted on a separate pulley fixedly attached to the pump 56 for rotation therewith, having an outer circumference substantially equal to and coaxial with an outer circumference of the pump 56.

[0026] The off-axis mechanical drive system 40, in one embodiment, preferably includes the outer drive sheave 52 coupled to the pump 56 of the torque converter 50, the motor pulley 34 coupled to the rotor of the electric machine 30, and a continuous belt 42. The outer drive sheave 52 and the motor pulley 34 are rotatably coupled via the continuous belt 42 to transmit torque therebetween. The outer drive sheave 52 and the motor pulley 34 may be suitably configured with belt contact surfaces in the form of a single circumferential groove, multiple circumferential grooves, radial teeth, or another suitable arrangement, and the continuous belt 42 is configured according to the belt contact surfaces of the outer drive sheave 52 and the motor pulley 34.Preferably, the off-axis mechanical drive system 40 includes a belt tensioner to ensure that the continuous belt 42 makes contact with at least 180° of the belt contact surfaces of the outer drive pulley 52 and the motor pulley 34.

[0027] The continuous belt 42 may be constructed from Kevlar cords in one embodiment. In one embodiment, the sheave ratio between the outer drive sheave 52 and the motor pulley 34 is 2.5:1. Alternatively, the outer drive sheave 52 and the motor pulley 34 are rotatably coupled via a continuous chain to transmit torque therebetween. Alternatively, the outer drive sheave 52 and the motor pulley 34 are rotatably coupled via intermeshing gears to transmit torque therebetween.

[0028] The transmission 60, in one embodiment, may be arranged in a stepped transmission configuration and may include one or more differential gear sets and activatable clutches configured to provide torque transfer in one of a plurality of fixed gear states across a range of speed ratios between the engine 10, the input member 52, and the output member 62. The transmission 60 may include a first speed sensor in the form of a Hall-effect sensor or other suitable sensor that may be configured to monitor a speed of the input member 51, and / or a second speed sensor that may be configured to monitor a speed of the output member 62.The transmission 60 includes any suitable design and may be an automatic transmission that automatically shifts between the fixed gear states to operate at a gear ratio that achieves a preferred match between an output torque demand and an engine operating point. The transmission 60 automatically performs upshifts to shift to a gear state with a lower numerical multiplication ratio (gear ratio) at preset speed / load points and performs downshifts to shift to a gear state with a higher numerical multiplication ratio at preset speed / load points. The transmission 60 may be controlled using a controllable hydraulic circuit that communicates with a transmission controller, which may be integral with or separate from the controller 15.The transmission controller preferably controls the torque converter clutch 59. The transmission 60 performs upshifts to shift into a fixed gear having a lower multiplication ratio (gear ratio) and performs downshifts to shift into a fixed gear having a higher numerical multiplication ratio. A transmission upshift may require a reduction in engine speed so that the engine speed matches a transmission output speed multiplied by the gear ratio at a gear ratio associated with a target gear state. A transmission downshift may require an increase in engine speed so that the engine speed matches the transmission output speed multiplied by the gear ratio at a gear ratio associated with the target gear state.Transmission and transmission shift designs are known and will not be described in detail herein. Transmission actuation may be described in the context of a control variable that may be communicated to the transmission 60 that relates to a selected fixed gear state.

[0029] The driveline 90 may include a differential gear device 92 that mechanically couples to an axle(s) 94, which in one embodiment mechanically couples to a wheel(s) 96. The driveline 90 transfers traction between an output member of the transmission 60 and a road surface via the wheel(s) 96. The driveline 100 is illustrative, and the concepts described herein apply to other driveline systems of similar configurations.

[0030] The inverter module 36 is configured with suitable control circuitry including power transistors, e.g., integrated-gate bipolar transistors (IGBTs), for transforming DC electrical power into AC electrical power and transforming AC electrical power into DC electrical power. The inverter module 36 preferably uses pulse-width modulation (PWM) control of the IGBTs to convert stored DC electrical power from the 48V battery 70 into AC electrical power to drive the electric machine 30 to generate torque. Similarly, the inverter module 36 converts mechanical power transmitted to the electric machine 30 into DC electrical power to generate electrical energy that can be stored in the 48V battery 70, including as part of a regenerative braking control strategy.The inverter module 36 receives motor control commands from the controller 15 and controls inverter states to provide a desired motor drive operation or regenerative braking operation. In one embodiment, an additional DC / DC electric power converter 76 electrically connects to the bus and provides electrical power to charge the low-voltage battery 78 via a low-voltage bus. Such electrical power connections are known and will not be described in detail. The low-voltage battery 78 provides low-voltage electrical power to low-voltage systems on the powertrain system 100 and the vehicle, including, for example, the starter motor 20, power windows, HVAC fans, seats, and other devices. In one embodiment, the low-voltage battery 78 is configured to operate at a nominal 12V DC level.

[0031] The 48V battery 70 is preferably arranged to provide electrical power at a nominal voltage level of 48V DC and may be any DC power source, including, without limitation, a multi-cell lithium-ion device, an ultracapacitor, or other suitable device. Monitored parameters related to the 48V battery 70 preferably include a state of charge (SOC), temperature, and others. In one embodiment, the 48V battery 70 may electrically connect to a remote source of electrical power external to the vehicle via an on-board battery charging device for charging while the vehicle is stationary.

[0032] Controller 15 is signally connectable to an operator interface (not shown) and provides hierarchical control of a plurality of control devices to accomplish operational control of individual elements of powertrain 100, including, for example, inverter module 36, motor controller, and transmission controller. Controller 15 communicates with each of inverter module 36, motor controller, and transmission controller, either directly or via a communication bus 16, to monitor operation and their control operations.

[0033] The terms controller, control module, module, controller, control unit, processor, and similar terms refer to any one or various combinations of an application-specific integrated circuit(s) (ASIC(s), electronic circuit(s), central processing unit(s), e.g., microprocessor(s), and an associated non-transitory memory component in the form of memory and mass storage devices (read-only memory, programmable read-only memory, random access memory, hard disk drive, etc.). The non-transitory memory component is capable of executing machine-readable instructions in the form of one or more software or firmware programs or routines, combinational logic circuit(s), input / output circuit(s) and devices, signal conditioning or-conditioning and buffer circuits and other components accessible by one or more processors to provide described functionality. Input / output circuit(s) and devices include analog-to-digital converters and associated devices that monitor inputs from sensors, where such inputs are monitored at a preset sampling frequency or in response to a trigger event. Software, firmware, programs, instructions, control routines, code, algorithms, and similar terms refer to any controller-executable set of instructions that includes calibrations and lookup tables.Each controller executes one or more control routines to provide desired functions, including monitoring inputs from sensing devices and other network controllers and executing control and diagnostic routines to control actuator operation. Routines can be executed at regular intervals or can be executed in response to the occurrence of a trigger event. Communication between controllers and communication between controllers, actuators, and / or sensors can be accomplished using a direct-wired connection, a connection via network communication buses, a wireless connection, a serial peripheral interface bus, or any other suitable communication connection.Communication involves exchanging data signals in any suitable form, including, for example, electrical signals over a conductive medium, electromagnetic signals over air, optical signals over optical waveguides, and the like. Data signals may include signals representing inputs from sensors, signals representing actuator commands, and communication signals between controllers.

[0034] Operator-responsive vehicle operation includes operating modes of acceleration, deceleration, steady cruise, coasting, and idle. Acceleration mode includes an operator request to increase vehicle speed. Deceleration mode includes an operator request to decrease vehicle speed. Steady cruise mode includes vehicle operation in which the vehicle is currently moving at a speed without an operator request for either braking or acceleration, where the vehicle speed is determined based on the current vehicle speed and momentum, the vehicle's air resistance and rolling resistance, and the driveline inertial drag.Coasting mode involves vehicle operation where vehicle speed is above a minimum threshold speed and the operator's throttle pedal input is at a point less than necessary to maintain the current vehicle speed. Idle mode involves vehicle operation where vehicle speed is at or near zero.

[0035] The powertrain system 100 operates in one of a variety of modes, which can be selected and implemented during ongoing powertrain operation to perform vehicle functions of acceleration, braking, steady cruise, coasting, and idling. The powertrain modes include motor-only drive mode, electric-only drive mode, regenerative mode, and electric-assist motor drive mode with accompanying motor auto-start / auto-stop operations. In motor-only drive mode, the engine 10 is controlled to produce motive power while the electric machine 30 is idling. This mode can be commanded during acceleration or steady cruise of the vehicle.In all-electric drive mode, the electric machine 30 is controlled like a motor to produce motive power while the engine 10 is in the OFF state and disconnected by action of the engine disconnect clutch 24. This mode may be commanded during idling, acceleration, or steady or smooth cruising of the vehicle. In regenerative mode, the electric machine 30 is controlled like a generator to counter driveline torque and produce electrical power while the engine 10 is either in the OFF state and disconnected by action of the engine disconnect clutch 24. This mode may be commanded during coasting and braking of the vehicle. In electric-assist motor drive mode, the engine 10 and the electric machine 30 are controlled to produce motive power. This mode may be commanded during acceleration or steady or smooth cruising.command the vehicle to drive smoothly.

[0036] Fig. 3 schematically illustrates an isometric view of a portion of one embodiment of the off-axis mechanical drive system 340 coupled to an electrically driven torque machine (electric machine) 330 via a torque converter 350 coupled to an output member of an internal combustion engine (not shown) that is part of one embodiment of a hybrid powertrain system 300 including a plurality of torque-generating devices. The hybrid powertrain system 300 further includes a transmission and a driveline (not shown) for transmitting drive power to vehicle wheels (not shown) in response to operator inputs. The concepts described herein may apply to any suitable front-wheel drive, rear-wheel drive, or all-wheel drive powertrain configuration, with operation controlled by a controller.In this embodiment, the off-axis mechanical drive system 340 is preferably embodied as a belt drive including an outer drive pulley 352 annularly coupled to and with a pump 356 of the torque converter 350. Other elements of the off-axis mechanical drive system 340 include a motor pulley 332 coupled to a rotor of the electric machine 330, an endless or continuous belt 342, and a belt tensioner 334. The belt tensioner 334 is arranged to urge the continuous belt 342, ensuring that the continuous belt 342 makes contact with at least 180° of the belt contact surfaces of the outer drive pulley 352 and the motor pulley 332, thus minimizing or completely eliminating belt slippage. In one embodiment, and as illustrated, the belt tensioner 334 is a two-sided belt tensioner.Alternatively, the belt tensioning device may be implemented as a single-sided device. The outer drive sheave 352 and the motor pulley 332 are rotatably coupled via the continuous belt 342 to transmit torque therebetween. The outer drive sheave 352 and the motor pulley 334 may be suitably formed with belt contact surfaces and are arranged to have a plurality of circumferential grooves in their respective annular surfaces. Some of the circumferential grooves in the annular surface of the outer drive sheave 352 are designated by numeral 353. The continuous belt 342 is preferably formed according to the circumferential grooves in the annular surfaces of the outer drive sheave 352 and the motor pulley 334 and thus has a plurality of inwardly facing circumferential grooves. The continuous belt 342 may, in one embodiment, be made of Kevlar cords.In one embodiment, the pulley ratio between the outer drive pulley 352 and the motor pulley 334 is 2.5:1.

[0037] Fig.4 schematically illustrates an isometric view of a portion of another embodiment of the off-axis mechanical drive system 440 coupled to an electrically driven torque machine (electric machine) 430 via a torque converter 450 coupled to an output member of an internal combustion engine (not shown) that is part of an embodiment of a hybrid powertrain system 400 including a plurality of torque-generating devices. The hybrid powertrain system 400 further includes a transmission and a driveline (not shown) for transmitting drive power to vehicle wheels (not shown) in response to operator inputs. The concepts described herein may apply to any suitable front-wheel drive, rear-wheel drive, or all-wheel drive powertrain configuration, with operation controlled by a controller.In this embodiment, the off-axis mechanical drive system 440 is preferably embodied as a belt drive including an outer drive pulley 452 annularly coupled to and with a pump 456 of the torque converter 450. Other elements of the off-axis mechanical drive system 440 include a motor pulley 432 coupled to a rotor of the electric machine 430 and a continuous belt 442. In this embodiment, there is no belt tensioner. The outer drive pulley 452 and the motor pulley 432 are rotatably coupled via the continuous belt 442 to transmit torque therebetween. The outer drive pulley 452 and the motor pulley 432 are suitably configured with belt contact surfaces and arranged to have a plurality of radial teeth in their respective annular surfaces.Some of the radial teeth in the annular surface of the outer drive sheave 452 are designated by numeral 453. The continuous belt 442 is preferably configured according to the circumferential grooves in the annular surface of the outer drive sheave 452 and the motor pulley 434 and thus has a plurality of inwardly facing radial teeth. The continuous belt 442 may, in one embodiment, be made of Kevlar cords. In one embodiment, the pulley ratio between the outer drive sheave 452 and the motor pulley 434 is 2.5:1. In this embodiment, belt tension is achieved by tensioners (not shown) that are adjusted during assembly or belt installation.

Claims

[1] Powertrain system (100) comprising: an internal combustion engine (10) including a crankshaft (12); an electric machine (30) including a rotatable shaft (32) coupled to a motor pulley (34); and a torque converter (50) comprising an impeller (58) and a pump (56) coupled to an outer drive pulley (52); wherein the outer drive pulley (52) of the torque converter (50) is rotatably coupled to the motor pulley (34) of the electric machine (30); wherein the electric machine (30) is coupled to the pump (56) of the torque converter (50) via the off-axis mechanical drive system (40); and wherein the crankshaft (12) is coupled to the pump (56) of the torque converter (50) via a clutch (24); characterized by , that the clutch (24) is a selectable one-way clutch; and that the outer drive pulley (52) is arranged on an outer periphery of the pump (56). [2] The powertrain system (100) of claim 1, further comprising a starter (20) rotatably coupled to the crankshaft (12). [3] The powertrain system (100) of claim 1, further comprising the electric machine (30) being electrically connected to an inverter (36) that is electrically connected to a source of electrical power, the source of electrical power being configured to operate at a voltage level less than 60 V DC. [4] The drive train system (100) of claim 1, wherein the outer drive pulley (52) of the torque converter (50) is rotatably coupled to the motor pulley (34) of the electric machine (30) via a continuous belt (42). [5] The drive train system (100) of claim 1, wherein the outer drive pulley (52) of the torque converter (50) is rotatably coupled to the motor pulley (34) of the electric machine (30) via a chain. [6] The powertrain system (100) of claim 1, further comprising a transmission (60) including an input member (51) and an output member (94), and a driveline (90); wherein the input element (51) of the transmission (60) is coupled to the impeller (58) of the torque converter (50); and wherein the output element (94) of the transmission (60) is coupled to the final drive (90). [7] The powertrain system (100) of claim 6, further comprising a controller (15) operatively coupled to the powertrain system (100), the controller (15) including a set of instructions, the set of instructions executable to automatically stop the internal combustion engine (10) and control operation of the powertrain system (100) in a purely electric drive mode to transfer drive power to the driveline (90). [8] The powertrain system (100) of claim 6, further comprising a controller (15) operatively connected to the powertrain system (100), the controller (15) including a set of instructions, the set of instructions executable to control operation of the powertrain system (100) in an electric-assist motor drive mode to transfer drive power to the driveline (90).

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