AN ELECTRIFYED DRIVE SYSTEM AND DEVICE

Abstract

A drive system (100) comprising: an electric rotary machine (10) with a rotatable shaft (12); a torque converter (50) comprising a fluidicstator (57), a pump (56), a turbine (58) and a normally closed torque converter coupling (52); a selectable one-way coupling (55) coupled to the fluidicstator (57); wherein the selectable one-way coupling (55) is coupled between the fluidicstator (57) and a stationary frame element (35); and an output element (59); wherein the rotatable shaft (12) is coupled to the pump (56) of the torque converter (50); and wherein the turbine (58) of the torque converter (50) is coupled to the output element (59).

Description

TECHNICAL AREA This disclosure relates to electrified drive systems for vehicles. BACKGROUND Electrified powertrains for vehicles include, for example, battery electric vehicles (BEVs), extended-range electric vehicles (EVs), plug-in hybrid electric vehicles (PEVs), and fuel cell hybrid electric vehicles (FEVs). As experienced professionals know, developing electrified powertrains involves optimizing and balancing traction, weight, pack size, range, drivability, and other factors. Vehicle developers strive for a fast, lightweight, and responsive propulsion system that can be housed in a vehicle and is capable of covering long distances with minimal need for recharging. Electric machines convert electrical energy into mechanical work by generating torque. In electric vehicles, including hybrid vehicles, electric motors, such as induction motors and permanent magnet motors, are used to propel the vehicles and, as electric generators, to recover braking energy. Generally, an electric motor consists of a rotor, which rotates during operation, and an electric stator, which is stationary. The rotor can contain a variety of permanent magnets and rotates relative to the stationary electric stator. The rotor is connected to a shaft that also rotates with the rotor. The rotor, including the permanent magnets, is separated from the electric stator by a predetermined air gap. The electric stator contains conductors in the form of wire windings. When electrical energy is supplied through the conductive wire windings, a magnetic field is generated.When electrical energy or power is fed into the conductive windings of the electric stator, the power can be transferred across the air gap by means of a magnetic flux, which generates a torque that acts on the permanent magnets in the rotor. In this way, mechanical power can be transferred to or taken away from the rotating shaft. In an electric vehicle, the rotor thus transmits torque via the rotating shaft, through a gearbox, to the vehicle's drive wheels. The direct coupling of an electric rotary machine to a drive train can lead to undesirable noise, vibration and / or harsh conditions in certain operating states. DE 10 2019 118 071 A1 describes a hydrodynamic torque converter and a drive train with such a torque converter, wherein the torque converter has an input side rotatable about an axis of rotation, an output side, a pump impeller, a turbine impeller, a guide wheel and a housing that accommodates a switching device at least partially, wherein the input side can be connected to an electric machine and the output side to a gearbox in a torque-locking manner, wherein the pump impeller is operatively connected to the input side, wherein the switching device can be switched between a first switching position and a second switching position, and in the first switching position connects the guide wheel to the housing and the turbine impeller to the output side in a torque-locking manner, wherein in the second switching position the switching device connects the guide wheel to the output side and the turbine impeller to the housing in a torque-locking manner. JP 2011-231857A describes a drive device capable of improving the energy efficiency of a vehicle. The drive device includes a motor-generator as the drive source. The device further includes a torque converter installed in a power transmission path between the motor-generator and a drive wheel. The torque converter has an engagement element installed such that it rotates integrally with an output part and switches between an engaged state, in which the torque converter is connected to an input part, and a disengaged state, in which the connection is disengaged. In addition, the torque converter includes a normally closed lock-up clutch in which the engagement element switches to the engaged state when not controlled. There is a need to incorporate torque management into an electrified powertrain to improve driving performance. DESCRIPTION According to the invention, an electrified drive system is described that maximizes power density, is easy to package, and improves driving performance. It comprises a drive system with an electric rotary machine having a rotatable shaft, a torque converter with a fluidic stator, a pump, a turbine, a normally closed torque converter coupling, a selectable one-way coupling connected to the fluidic stator, and an output element. The rotatable shaft is connected to the torque converter pump, and the torque converter turbine is connected to the output element. One aspect of the revelation is that the torque converter clutch is a normally closed clutch, with the torque converter clutch being controlled into an open state during a starting maneuver. Another aspect of the revelation includes the torque converter clutch, which is a dog clutch. Another aspect of the revelation is that the torque converter clutch is a preloaded friction clutch. Another aspect of the revelation includes the torque converter clutch, which is an electromagnetic clutch. According to the invention, the selectable one-way coupling is coupled between the fluidicstator and a stationary frame element. Another aspect of the disclosure includes the fact that the selectable one-way coupling is controlled to couple the fluidicstator to the stationary frame element in a first direction of rotation when the drive system is controlled to operate in a first direction. Another aspect of the disclosure includes the fact that the selectable one-way coupling is controlled to couple the fluidicstator to the stationary frame part in a second direction of rotation opposite to the first direction of rotation when the drive system is controlled to operate in a second direction opposite to the first. According to the invention, a drive system comprises an electric rotary machine with a rotatable shaft, a torque converter with a fluidic stator, a pump, a turbine, and a normally closed torque converter coupling, a selectable one-way coupling connected to the fluidic stator, wherein the selectable one-way coupling is coupled between the fluidic stator and a stationary frame element, an output element, and a drive train. The rotatable shaft of the electric rotary machine is connected to the pump of the torque converter, and the turbine of the torque converter is connected to the output element. The output element is connected to the drive train. The above features and advantages, as well as other features and advantages of the present teaching, are readily apparent from the following detailed description of some of the preferred embodiments and other embodiments for carrying out the present teaching as defined in the attached claims, in conjunction with the attached figures. BRIEF DESCRIPTION OF THE FIGURES One or more embodiments are now described by way of example with reference to the accompanying figures, in which: Fig. 1 schematically shows a drive system for an electrified drive train with an embodiment of an electric rotary machine coupled to a torque converter, according to the disclosure. Fig. 2 schematically shows a torque converter control process for controlling the operation of an embodiment of a torque converter used in an embodiment of the drive system described with reference to Fig. 1, in accordance with the disclosure. The accompanying figures are not necessarily to scale and may represent a somewhat simplified depiction of various features of the present disclosure as disclosed herein, including, for example, certain dimensions, orientations, positions, and shapes. Details associated with such features are partly determined by the intended application and operating environment. DETAILED DESCRIPTION With reference to the figures, which serve only to illustrate certain exemplary embodiments and not to limit them, Fig. 1 schematically shows elements of an embodiment of a drive system 100 comprising an electric rotary machine 10 coupled to a drive train 60 via a torque converter 50 and controlled by a controller 70. The same reference numerals refer to the same elements throughout the description. The description is given in connection with an axial orientation with axial reference line 15 and radial reference line 16. An electric axial-flux rotary machine is a type of electric motor design in which the gap between the rotor and the electric stator, and thus the direction of the magnetic flux between the two, is aligned parallel to the axis of rotation.In one embodiment, and as described herein, the electric rotary machine 10 is configured as a brushless permanent magnet direct current (DC) motor. In one embodiment, the electric rotary machine 10 comprises a rotatable shaft 12 coupled to the torque converter 50, which is coupled to the drive train 60 to provide the drive torque. In one embodiment, the drive system 100 is arranged on a vehicle, and the drive train 60 terminates at one or more vehicle wheels to generate tractive force. The vehicle may be a mobile platform in the form of a commercial vehicle, an industrial vehicle, an agricultural vehicle, a passenger car, an aircraft, a watercraft, a train, an all-terrain vehicle, a people carrier, a robot, and the like, but is not limited to such forms to fulfill the purposes of this disclosure. In one embodiment, the drive train 60 comprises a rigid or continuously variable transmission connected to the vehicle wheels via a drive shaft, transaxle, or differential. In another embodiment, the drive system 100 is stationary, and the drive train 60 terminates at an actuator, for example, a fluid pump. The electric rotary machine 10 is a multiphase high-voltage electric motor / generator configured to convert stored electrical energy into mechanical energy and vice versa, which can be stored in a high-voltage energy storage device (battery) 90. The battery 90 can be a high-voltage energy storage device, such as a multi-cell lithium-ion device, an ultracapacitor, or any other device without limitation. Monitored parameters relating to the battery 90 may include the state of charge (SOC), temperature, and others. In one embodiment, the battery can be electrically connected to a remote power source located outside the vehicle via a vehicle-integrated battery charger 90 (not shown) for charging while the vehicle is stationary.The battery 90 is electrically connected to an inverter module 80 via a high-voltage direct current bus in order to transmit high-voltage direct current electrical power to the electric rotary machine 10 via three-phase conductors in response to control signals from the control unit 70. As shown in Fig. 1, the electric rotary machine 10 is electrically connected to the battery 90 via a high-voltage bus through the inverter module 80. The inverter module 80 is equipped with control circuits containing power transistors, e.g., IGBTs, for converting high-voltage direct current to high-voltage alternating current and vice versa. The inverter module 80 can control the IGBTs by pulse-width modulation (PWM) to convert stored direct current from the battery 90 into alternating current, which drives the electric rotary machine 10 and generates torque. Similarly, the inverter module 80 converts the mechanical power transferred to the electric rotary machine 10 into electrical direct current power to generate electrical energy that can be stored in the battery 90, also as part of a regenerative braking control strategy.The inverter module 80 receives motor control commands and controls the inverter states to provide motor drive and regenerative braking functionality. In one embodiment, a DC / DC converter is electrically connected to the high-voltage bus to supply power to a low-voltage battery via a low-voltage bus. The low-voltage battery is electrically connected to an auxiliary power system to provide low-voltage current for low-voltage systems in the vehicle, such as power windows, HVAC fans, seats, and other equipment. The control unit 70 is operationally connected to the inverter module 80 to control the transfer of electrical energy between the battery 90 and a plurality of radially oriented, electrically conductive windings 32 of the stator 30.The control unit 70 controls the inverter module 80 to electrically activate the electrically conductive windings one after the other in order to exert a rotating magnetic force on a rotor to cause rotation, or to respond to a torque to decelerate the rotation. The torque converter 50 can be a fluidic torque coupling device arranged coaxially between the electric rotary machine 10 and the drive train 60. The torque converter 50 comprises a pump 56 rotatably connected to the rotatable shaft 12, a fluidic stator 57, and a turbine 58 rotatably connected to the output element 59, which is rotatably connected to the drive train 60. The torque converter 50 also comprises a controllable torque converter coupling 52 and a selectable one-way clutch (SOWC) 55. The torque converter coupling 52 can be configured as a jaw coupling, a preloaded friction coupling, or an electromagnetic coupling. The torque converter coupling 52 is configured as a normally closed coupling that is controlled to an open or disengaged state to allow the torque converter 50 to operate in a slip state under certain operating conditions, e.g.,during a starting maneuver or a gear change process. This arrangement of the torque converter clutch 52 as a normally open contact reduces the energy consumption for actuation and deactivation and contributes to improved reverse operation on an incline. The torque converter 50 provides a fluidic torque coupling between the pump 56 and the turbine 58 when the coupling 52 is deactivated or disengaged, and a mechanical torque coupling between the pump 56 and the turbine 58 when the coupling 52 is engaged. When the coupling 52 is deactivated or disengaged, a speed difference between the pump 56 and the turbine 58 can occur due to the fluid torque coupling; this is referred to as torque converter coupling slip. The torque converter coupling slip can be measured using speed sensors. The SOWC 55 is arranged to selectively couple the fluidic stator 57 to the stationary frame section 35, thus facilitating reverse operation when engaged by enabling torque multiplication during reverse operation of the electric rotary machine 10. The SOWC 55 is designed for two operating modes: a forward mode in which an input ring can rotate freely relative to an output ring, and a reverse mode in which the input ring is mechanically locked to the output ring in at least one direction of rotation. A forward / reverse selection mechanism is controlled either hydraulically or electrically. The SOWC 55 comprises a one-way clutch mechanism, a locking mechanism, and an actuator connected to and controlled by the control unit 70. The locking mechanism selectively locks and unlocks the one-way clutch mechanism and may include rocker, diode, strut, or claw clutch locking mechanisms.When the actuator controls the locking mechanism of the SOWC 55 into a first state, the output can rotate freely relative to the input in a first direction of rotation, but not freely relative to the input in a second, opposite direction of rotation. This allows the output element 59 to rotate in order to push the drive train 60 in a first direction, e.g., forward. When the actuator controls the locking mechanism of the SOWC 55 into a second state, the output cannot rotate freely relative to the input in the first direction of rotation, but can rotate freely relative to the input in a second, opposite direction of rotation. This allows the output element 59 to rotate in order to drive the drive train 60 in a second direction opposite to the first, e.g., reverse.A number of SOWC designs are known, including designs as a clamp, strut, roller, diode or latch, and the disclosure is not intended to be limited to the particular embodiments described herein. The addition of the SOWC 55 facilitates the coupling of the fluidic stator 57 with the stationary frame element 35 in a first direction of rotation (e.g., clockwise) or a second, opposite direction of rotation (e.g., counterclockwise). When the drive system 100 is commanded to operate in the forward direction, the SOWC 55 allows the fluidic stator 57 to rotate in the first direction but not in the second, opposite direction. When the drive system 100 is commanded to operate in the reverse direction, the SOWC 55 allows the fluidic stator 57 to rotate in the second, opposite direction but not in the first. Thus, the torque converter 50 can effect torque multiplication between the electric rotary machine 10 and the drive train 60 in both the first and second, opposite directions of rotation. The rotatable shaft 12 is connected to the pump 56 of the torque converter 50 in order to transmit the torque to the output element 59, which in one embodiment is connected to the drive train 60. The drivetrain 60 comprises one or more of the following elements: a transmission, a differential, a transaxle, half-shafts, etc. In one embodiment, the drivetrain 60 comprises a transmission. In one embodiment, the transmission may be arranged in a stepped gear configuration and comprise one or more differential gear sets and engageable clutches configured to transmit torque in one of several fixed gear states over a range of speed ratios between the output element 59 of the torque converter 50 and a drivetrain component. The transmission may be of one of several configurations and may be an automatic transmission that shifts automatically between the fixed gear states. In one embodiment, the drivetrain 60 can comprise a transmission mechanically connected to one or more axles, which in turn are mechanically connected to one or more wheels. The drivetrain transmits the tractive force to a road surface. The transmission of the drivetrain 60 can consist of a front transaxle and half-shafts (not shown) rotatably connecting the output element 59 to one or more wheels. Alternatively, the transmission set can take the form of a rear differential and axles rotatably connecting the output element 59 to one or more of the wheels. Alternatively, the transmission set can consist of a front transaxle connected to a rear drive shaft coupled to a differential that rotatably connects the output element 59 to one or more of the wheels 66.Alternatively or additionally, a power take-off gearbox (not shown) can be rotatably connected to the output element 59. The drive system 100 is exemplary, and the concepts described here also apply to other drive systems that are similarly configured. In one embodiment, a fluidic system 85 is arranged to supply the torque converter 50 with hydraulic fluid and to be in fluid communication with heat exchanger elements located on the electric rotary machine 10 and the inverter module 80. The fluidic system 85 comprises, as non-limiting examples, a fluidic pump, a sump, a cooling element, and associated piping elements, and is configured to supply the torque converter 50 with hydraulic fluid and to dissipate heat from the electric machine 10 and the inverter module 80. The terms control unit, control module, module, controller, control unit, processor, and similar terms refer to one or more combinations of application-specific integrated circuits (ASICs), electronic circuits, central processing units (CPUs), such as microprocessors, and associated non-transient memory components in the form of working memory and storage devices (read-only memory, programmable read-only memory, direct access memory, hard disk drive, etc.). The non-transient 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 one or more processors can access to provide a described functionality.Input / output circuits and devices include analog-to-digital converters and related devices that monitor sensor inputs, either at a preset sampling rate or in response to a triggering event. Software, firmware, programs, instructions, control routines, code, algorithms, and similar terms refer to sets of instructions executable by control devices, including calibrations and lookup tables. Each control device executes control routine(s) to provide the desired functions, including monitoring inputs from measuring instruments and other networked control devices, and executing control and diagnostic routines to manage the operation of actuators. The routines can be executed at regular intervals, for example, every 100 microseconds or 3.125, 6.25, 12.5, 25, and 100 milliseconds during operation.Alternatively, routines can be executed in response to a triggering event. Communication between control units and between control units, actuators, and / or sensors can occur via a direct wired connection, a networked communication bus, a wireless connection, a serial peripheral interface bus, or another communication link. This communication involves the exchange of data signals in various forms, such as electrical signals over a conductive medium, electromagnetic signals over air, optical signals over fiber optics, and so on. Data signals can include sensor inputs, actuator commands, and communication signals between control units.The terms “dynamic” and “dynamic” used here describe steps or processes that are executed in real time and are characterized by the fact that the states of parameters are monitored or otherwise determined and the states of the parameters are updated regularly or periodically during the execution of a routine or between iterations of the execution of the routine. The term “system” as used here may refer to one or a combination of mechanical and electrical actuators, sensors, controllers, application-specific integrated circuits (ASICs), combinational logic circuits, software, firmware and / or other components arranged to provide the described functionality. Fig. 2 schematically shows a torque converter control process 200 for controlling the operation of an embodiment of the drive system 100 described in Fig. 1, including the electric rotary machine 10, the torque converter 50, and the drive train 60. The process 200 is represented as a collection of blocks in a logical flowchart, which depicts a sequence of operations that can be implemented in hardware, software, or a combination thereof. In the context of software, the blocks represent computer instructions that, when executed by one or more processors, perform the operations mentioned. During vehicle operation, the vehicle is monitored (S210). The monitored parameters may include the driver's request to accelerate or decelerate, as well as other parameters relating to vehicle speed, etc. When the monitored parameters indicate a request or need for a torque increase, such as a request for vehicle acceleration, a request for a transmission shift, a request for vehicle braking and associated regenerative braking to charge the battery, a starting maneuver, etc. (S212), the torque converter clutch 52 is commanded to an open or deactivated state to enable a fluidic torque coupling in a slip state between the pump 56 and the turbine 58 of the torque converter 50 (S214). The operation of the vehicle is monitored, and when the need for the torque increase is fulfilled (S216), the electric rotary machine 10 is controlled to synchronize the rotational speeds to enable the activation of the torque converter clutch 52 and thus achieve a mechanical coupling. The detailed description and the drawings or figures are supporting and descriptive of the present teaching, but the scope of the present teaching is defined exclusively by the claims. While some of the best modes and other embodiments for carrying out the present teaching have been described in detail, various alternative designs and embodiments for carrying out the present teaching are defined in the accompanying claims.

Claims

A drive system (100) comprising: an electric rotary machine (10) with a rotatable shaft (12); a torque converter (50) comprising a fluidicstator (57), a pump (56), a turbine (58) and a normally closed torque converter coupling (52); a selectable one-way coupling (55) coupled to the fluidicstator (57); wherein the selectable one-way coupling (55) is coupled between the fluidicstator (57) and a stationary frame element (35); and an output element (59); wherein the rotatable shaft (12) is coupled to the pump (56) of the torque converter (50); and wherein the turbine (58) of the torque converter (50) is coupled to the output element (59). The drive system (100) according to claim 1, wherein the output element (59) is rotatably connected to a drive train (60). The drive system (100) according to claim 1, wherein the normally closed torque converter clutch (52) is controlled to an open state under certain operating conditions. The drive system (100) according to claim 1, wherein the normally closed torque converter coupling (52) comprises a jaw coupling. The drive system (100) according to claim 1, wherein the normally closed torque converter coupling (52) comprises a preloaded friction coupling. The drive system (100) according to claim 1, wherein the normally closed torque converter coupling (52) comprises an electromagnetic coupling. The drive system (100) according to claim 1, wherein the selectable one-way coupling (55) is controlled such that it couples the fluidicstator (57) with the stationary frame element (35) in a first direction of rotation when the drive system (100) is controlled for operation in a first direction. The drive system (100) according to claim 7, wherein the selectable one-way coupling (55) is controlled such that it couples the fluidicstator (57) to the stationary frame element (35) in a second direction of rotation which is opposite to the first direction of rotation when the drive system (100) is controlled to operate in a second direction which is opposite to the first direction. A drive system (100) comprising: an electric rotary machine (10) with a rotatable shaft (12); a torque converter (50) comprising a fluid icstator (57), a pump (56), a turbine (58) and a normally closed torque converter coupling (52); a selectable one-way coupling (55) coupled to the fluid icstator (57); wherein the selectable one-way coupling (55) is coupled between the fluid icstator (57) and a stationary frame element (35); and an output element (59); and a drive train (60); wherein the rotatable shaft (12) of the electric rotary machine (10) is coupled to the pump (56) of the torque converter (50); wherein the turbine (58) of the torque converter (50) is coupled to the output element (59); and wherein the output element (59) is coupled to the drive train (60).

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