Patent Description:
The disclosure relates generally to hybrid electric vehicles and powertrains.

A powertrain of an automobile or other vehicle generates power for delivery of motive force. In a conventional automobile, the powertrain often includes an internal combustion engine and a transmission. The powertrain may also be considered to include components of a vehicle driven by the engine and transmission, or drivetrain. The drivetrain of an automobile typically includes a drive shaft, one or more differentials, one or more axles, and wheels.

Hybrid vehicles use multiple sources of power to move the vehicle. The power sources typically combine an internal combustion engine and an electric motor system. The electric motor system often includes a set of batteries to drive one or more electric motors. An electric motor of a hybrid vehicle may be configured for operation as a generator during a regenerative braking mode to store energy in the batteries for later use.

Hybrid and other automobile vehicles are often configured with an internal combustion engine with a low number of cylinders. An engine with only a single cylinder (or other engines with few cylinders) may provide better fuel efficiency while remaining relatively simple and economical in construction.

Engines with few cylinders unfortunately exhibit large fluctuations in torque over each cycle of operation. The resulting output torque may have as high as <NUM>% variation compared to its mean. The fluctuations in torque lead to large torsional vibrations that propagate through the powertrain. Devices are typically placed along the powertrain to absorb the torsional vibrations. For example, a flywheel or damper may be mounted on a drive shaft or placed at other locations along the kinematic chain of the vehicle.

Incorporation of the absorption devices undesirably increases the complexity of engines with few cylinders. Despite the increased complexity, the energy dissipated by the devices is nonetheless wasted.

<CIT> discloses a vehicular system in accordance with the pre-characterising portion of claim <NUM>.

In accordance with a first aspect of the present invention, there is provided a vehicular system as defined in claim <NUM>.

In accordance with a second aspect of the present invention, there is provided a method of controlling a vehicle drivetrain as defined in claim <NUM>.

Embodiments of the present invention are defined in the appendant dependent claims.

For a more complete understanding of the disclosure, reference should be made to the following detailed description and accompanying drawing figures, in which like reference numerals identify like elements in the figures.

While the disclosed systems and methods are susceptible of embodiments in various forms, there are illustrated in the drawing (and will hereafter be described) specific aspects of the invention.

The disclosure relates to vibration absorption and regenerative controllable powertrains in hybrid electric vehicles (HEVs). Described herein are systems that may be operative as a regenerative vibration absorber and/or a controllable differential or transmission. The disclosed systems may control the output torque and angular velocity (e.g., revolutions per minute, or rpm) as desired by the vehicle driver while transforming the unused torque/power into electrical energy to charge a capacitor or a battery or while supplying additional toque/power from a battery or a capacitor. The disclosed systems may thus be configured as an electromechanical hub for a vehicle. The electromechanical hub controls the flux of torque/power in the powertrain. The electromechanical hub may include a series of electromagnetic machines embedded in the drivetrain. These machines are coupled electromagnetically and mechanically.

The electromagnetic machines may be coupled in a variety of arrangements. For example, one or more (e.g., two) of the electromagnetic machines may be disposed in a concentric arrangement in which respective armatures of each electromagnetic machine are coupled to one another radially. Alternatively or additionally, one or more (e.g., two) electromagnetic machines may be disposed in a laterally sequential arrangement in which respective armatures of each electromagnetic machine are coupled to one another frontally. Alternatively or additionally, one or more (e.g., two) electromagnetic machines may be disposed in a sequential arrangement in which respective armatures of each electromagnetic machine are coupled to one another radially. Various combinations of these arrangements may be used.

The disclosed systems may be configured to capture the energy of the torsional vibrations that would be otherwise dissipated in other drivetrains. The captured energy may then be used to charge batteries, capacitors, and/or other energy storage units of the vehicle.

The disclosed systems are not limited to use as regenerative vibration absorbers. The disclosed systems may be alternatively or additionally used or configured as a controllable differential device. For example, angular velocity differential functionality provided by the disclosed systems may replace the typically mechanical gears of a vehicle. The disclosed systems may be operative to control the output torque and/or output angular velocity (rpm) as desired by the vehicle driver while transforming the unused or harnessed torque/power into electrical energy to power an electrical drive directly and/or provide a charge to a capacitor or battery. The disclosed systems may also control the output torque and angular velocity (rpm) as desired by the vehicle driver while supplying additional torque/power from a battery or a capacitor. In these and other ways, the disclosed systems may include or be configured as an electromechanical hub. The hub may control the flux of torque/power in the powertrain of a vehicle. The disclosed systems may thus be configured for operation in a variety of modes, including a vibration suppression mode, a transmission mode, a differential mode, a hybrid drive mode, a charging mode, an electric-only drive mode, and combinations thereof.

With reference to the drawing figures, <FIG> depicts a hybrid vehicle <NUM> having an internal combustion engine (ICE) <NUM>, an electromechanical hub <NUM> mechanically coupled to the internal combustion by a crankshaft <NUM>, a drivetrain <NUM> mechanically coupled to the electromechanical hub <NUM> by a drive shaft <NUM>, and a supervisory controller <NUM> to control operation of the electromechanical hub <NUM>, an electrical energy storage system <NUM>, and a number of electrical loads <NUM>. The electromechanical hub <NUM> includes a plurality of electromagnetic machines <NUM>, <NUM>, and <NUM>. An input or initial stage machine <NUM> is mechanically coupled to the crankshaft <NUM>. An output or final stage machine <NUM> is mechanically coupled to the drive shaft <NUM>. A mid-stage machine <NUM> electromagnetically couples the initial and final stage machines or the mid-stage machine <NUM> may electromagnetically couple the crankshaft <NUM> and the drive shaft <NUM>. In an electromagnetic coupling there may be no mechanical coupling connecting the machines or the shafts, but instead electromagnetic forces provided by the mid-stage machine <NUM> may provide the coupling. The electromechanical hub <NUM> also includes a power controller <NUM> configured to control current and/or voltage flowing through the electromagnetic machines <NUM>, <NUM>, and <NUM>.

Mid-stage machine <NUM> is electromagnetically and mechanically coupled to the other electromagnetic machines <NUM> and <NUM>. For example, the mid-stage machine <NUM> may be coupled with the initial stage machine <NUM> and/or the final stage machine <NUM> using intermediate shafts along with optional mechanical coupling devices to allow for proper rotational operation of the system. This mechanical coupling may allow the electromagnetic machines <NUM>, <NUM>, and <NUM> to be placed at different physical locations throughout a vehicle, but still be connected to allow for the electromagnetic coupling of the crankshaft <NUM> to the drive shaft <NUM> using the mid-stage machine <NUM>. For example, the initial stage machine <NUM> may be physically attached to the body of the ICE and coupled with the mid-stage machine <NUM> such that the mid-stage machine <NUM> is physically located near an axle of the vehicle <NUM>. Thus, in some cases, the mid-stage machine <NUM> and the initial stage machine <NUM> are not physically adjacent to each other, but are still coupled. The electromechanical hub <NUM> may be configured to provide a differential in angular velocity between a crankshaft and a drive shaft. The electromechanical hub <NUM> may alternatively, or additionally, be configured to dampen vibrations of the crankshaft. Also, the electromechanical hub may alternatively, or additionally, be configured to drive, or otherwise provide power to, the drive shaft <NUM>.

The crankshaft <NUM> may be a crankshaft of the ICE <NUM>. Alternatively, the crankshaft <NUM> may be a shaft coupled or linked to the crankshaft of the ICE <NUM>. Similarly, the drivetrain <NUM> and the electromechanical hub <NUM> may share the drive shaft <NUM> or have respective drive shafts coupled or linked to one another. Further, as described above, the three machines <NUM>, <NUM>, and <NUM> may be spaced and/or located at various locations throughout the drivetrain <NUM>. For example, the final stage machine <NUM> may be located adjacent to a differential, or further along the drive train <NUM> such as at a wheel hub.

Each electric machine <NUM>, <NUM>, and <NUM> may be operated as an electric motor, an electric generator, or in a bypass mode in which power is neither added nor captured by the machine. The operation of each machine is controlled by a power controller <NUM> of the electromechanical hub <NUM>. The power controller <NUM> may include a current controller, a voltage controller, or both. The power controller <NUM> may include power electronic circuitry <NUM> to control the application of power to, or the reception of power from, each machine <NUM>, <NUM>, and <NUM> and/or control the capture of power from each machine <NUM>, <NUM>, and <NUM>.

The initial stage machine <NUM> may operate as a torsional vibration dampener through an application of dampening torque to the crankshaft <NUM> to account for and/or counter the variations of output torque across an ICE <NUM> piston cycle. The torque may be applied with an electromechanical operation of the initial stage machine <NUM> as controlled by the power controller <NUM> described below. In one aspect, the crankshaft may also have a sensor <NUM> positioned to determine a rotational position and/or output torque of the crankshaft <NUM>. The dampening torque to be applied at any given angular position of the crankshaft <NUM> may be determined using the sensor <NUM>. For example, the sensor <NUM> may measure torque of the shaft. The initial stage machine <NUM> may then vary the dampening torque accordingly to account for the variations in torque of the crankshaft throughout the various angular positions of a piston cycle by directly accounting for the variations of torque detected by the sensor <NUM>. In another example, the sensor <NUM> may capture or detect an angular position of the crankshaft <NUM>. The output torque of the ICE <NUM> may be determined based on the angular position. For example, torque values may be mapped and associated with respective angular positions of a rotation of the crankshaft <NUM>. This map and the angular position readings of the sensor <NUM> may be used to determine and control the dampening torque applied to the crankshaft <NUM> by the initial stage machine <NUM>.

An electric machine, such as the initial stage machine <NUM>, operating in a vibration suppression mode, or as a torsional vibration dampener, may also capture energy of the crankshaft <NUM> torsional vibrations, thus operating as a generator. For example, at certain angular positions throughout the crankshaft <NUM> cycle the torque generated by the ICE <NUM> may be higher than at other positions of the cycle, and possibly equal to or higher than the desired dampening torque intended to account for the variance of torque throughout the cycle. At these higher torque positions, energy may be captured using an electric machine operating in a vibration dampening mode, as the ICE <NUM> generated torque is driving the electric machine, resulting in a net positive power gain that may be stored in a storage device <NUM>, or used by other electric machines or electrical loads <NUM> of the vehicle <NUM>. At the positions having lower crankshaft torque, energy may be supplied by the electric machine to maintain the torque levels and dampen the torsional vibrations. In an example, the electric machine operating as a torsional vibration dampener may be operated with a dampening torque at a level that matches the highest torque output at angular positions of the crankshaft <NUM>. In this example, any energy supplied by the torsional vibration due to torque variations may be captured by the electric machine.

The power controller <NUM> is communicatively coupled to a supervisory controller <NUM> configured to establish or determine an operational mode for the electromechanical hub <NUM>. The supervisory controller <NUM> may generate or determine control signals based on various drive control inputs. For example, the supervisory controller <NUM> may receive an input signal or data representative of a throttle input <NUM> indicative of a desired power, torque, or speed output of the vehicle <NUM>. The power controller <NUM> may be responsive to the one or more control signals developed by the supervisory controller <NUM>. In some aspects, the supervisory controller <NUM> may include a processor <NUM> and a memory <NUM> in which instructions for the processor <NUM> are stored. The supervisory controller <NUM> may include one or more digital controllers.

The energy storage system (or device) <NUM> may have any number of storage devices for storing energy captured by the electromechanical hub <NUM>. In this example, the energy storage system <NUM> includes one or more capacitors <NUM> and one or more batteries <NUM>.

With reference to <FIG>, the electromechanical hub includes a three electrical or electromagnetic machines. The machines may be arranged in various architectures. <FIG> depicts an architecture in which armatures of each machine are disposed in a lateral or frontal sequential arrangement. <FIG> depicts an architecture in which armatures of each machine are disposed in a radial concentric arrangement. <FIG> depicts an architecture in accordance with the claimed invention in which armatures of each machine are disposed in a radial sequential arrangement. As shown in <FIG>, the electromechanical hub of the disclosed systems may include a number of sub-assemblies. An input or crankshaft assembly <NUM> is coupled to an internal combustion engine (ICE). The crankshaft assembly <NUM> further includes a radial arm <NUM> or other support that carriers multiple armatures <NUM> and <NUM> (e.g., one on each of the radial supports) of the initial stage machine <NUM> and the mid-stage machine <NUM> (described further below). A downstream or drivetrain shaft assembly <NUM> includes a radial arm <NUM> or other support that carriers armatures <NUM> and <NUM> of the mid-stage machine <NUM> and the final stage machine <NUM>. A stator assembly <NUM> includes a housing <NUM> or other support structure upon which stator armatures <NUM> of the first stage machine <NUM> and stator armature <NUM> of the and final stage machine <NUM> are mounted. The housing <NUM> may be co-mounted with the ICE <NUM>.

The shaft assemblies <NUM> and <NUM> are electromagnetically coupled and interacting through the electromagnetic fields developed by, or in connection with, the respective machines. Taken together, armatures of the shaft assemblies <NUM> and <NUM> form a regenerative electrical machine. Similarly, armatures of the shaft assembly <NUM> and the support structure <NUM> are also interacting through another electromagnetic field. Taken together, the armatures <NUM> and <NUM> of the shaft assembly <NUM> and the support structure <NUM> form another regenerative electrical machine. Similarly, armatures <NUM> and <NUM> of the shaft assembly <NUM> and the support structure <NUM> interact through another electromagnetic field and form another electrical machine.

The machines are coupled to the ICE <NUM>, to the storage device <NUM> (e.g., battery), and to other (downstream) elements of the powertrain. The electrical currents and/or voltages to the armatures of the crankshaft assembly <NUM>, the drive shaft assembly <NUM>, and the stator assembly <NUM> are controlled by the power controller <NUM>, which, in turn, is directed by the supervisory controller <NUM>. By controlling these currents and/or voltages, the angular velocity of the crankshaft <NUM> and the angular velocity of the driveshaft <NUM> may be controlled and/or set independently. Hence, the electromechanical hub may be configured to operate as a differential where the input shaft (<NUM>) and the output shaft (<NUM>) have distinct angular velocities (rpm) and/or are otherwise controlled independently.

The construction of the armatures may vary. In some aspects, the armatures on the drive shaft assembly <NUM>, and the stator assembly <NUM> may be permanent magnets.

The disclosed systems may be configured for operation in one of several modes. The disclosed systems may be configured for operation as a regenerative differential powertrain with embedded vibration suppression and isolation. Torsional vibrations may be suppressed through the operation of any one or more of the electromagnetic machines. The disclosed systems may be configured for operation in a drive mode as a differential through independent control of both the input shaft and the output shaft. Such independent control may be accomplished through control of electric currents and/or voltages to the plurality of machines.

In one drive mode of operation, the drivetrain is driven only with power from the storage device <NUM> (i.e., without power from the ICE). For example, power may be provided via the final stage machine <NUM>. In another drive mode, the drivetrain is driven by both power from the ICE <NUM> and the storage device <NUM>. In such cases, the initial stage machine <NUM> may be controlled to suppress or remove torsional vibrations (e.g., configured to provide smoothing), the machine mid-stage machine <NUM> may couple the initial and final stage machines, and the final stage machine <NUM> may provide additional torque. In some cases, the initial stage machine <NUM> may also provide torque. In another drive mode, power from the ICE <NUM> is used to charge the storage devices <NUM> and drive the drivetrain <NUM>. In such cases, the initial stage machine <NUM> may be inoperable or provide smoothing, the mid-stage machine <NUM> may provide smoothing, and the final stage machine <NUM> may charge the storage device <NUM>. In yet other drive modes, the machines may be controlled to act as a differential or transmission device. The mid-stage machine <NUM> may provide slippage between the input and output shafts and/or allow the shafts to have different angular velocities (rpm) and/or torque levels.

The exemplary armature arrangements shown in <FIG> provide different options for incorporating the disclosed systems into a vehicle. The frontal or lateral arrangement of <FIG> provides a relatively compact system, but at the expense of lower surface area in the armature windings, which may lead to less electromagnetic coupling and, thus, reduced torque. The concentric radial arrangement of <FIG> is a relatively short, but radially wider arrangement that increases the winding surface area and, thus, electromagnetic coupling. The concentric arrangement may, however, lead to increased interference between non-adjacent armatures. The concentric arrangement may also include or involve a double or other bearing structure to allow the shafts to enter and exit a consolidated electromechanical hub. The radial sequential arrangement of <FIG> (the arrangement used in the embodiment of the invention) may exhibit relatively good coupling with less interference, but at the expense of increased length.

The supervisory controller <NUM> of the disclosed systems may include one or more processors, such as, a central processing unit (CPU). The supervisory controller may thus include multiple controllers or processors for respectively controlling, directing, or otherwise communicating with one or more of the above-described system components (e.g., the power controller <NUM>). Other components, such as the power controller <NUM>, may also include one or more processors.

The processor <NUM> of the supervisory controller <NUM> may be a component in a variety of systems. The processor <NUM> may be one or more general processors, digital signal processors, application specific integrated circuits, field programmable gate arrays, networks, digital circuits, analog circuits, combinations thereof, or other now known or later developed devices for analyzing and processing data. The processor may implement a software program, such as code generated manually (i.e., programmed).

The supervisory controller <NUM> may include a memory <NUM>. The memory <NUM> may communicate via a bus. The memory <NUM> may be a main memory, a static memory, or a dynamic memory. The memory <NUM> may include, but may not be limited to computer readable storage media such as various types of volatile and non-volatile storage media, including but not limited to random access memory, read-only memory, programmable read-only memory, electrically programmable read-only memory, electrically erasable read-only memory, flash memory, and the like. In one case, the memory <NUM> may include a cache or random access memory for the processor. Alternatively or additionally, the memory may be separate from the processor, such as a cache memory of a processor, the system memory, or other memory. The memory <NUM> may be an external storage device or database for storing data. Examples may include a hard drive, memory card, memory stick, or any other device operative to store data. The memory may be operable to store instructions executable by the processor <NUM>. The functions, acts or tasks illustrated in the figures or described herein may be performed by the programmed processor executing the instructions stored in the memory. The functions, acts or tasks may be independent of the particular type of instruction set, storage media, processor or processing strategy and may be performed by software, hardware, integrated circuits, firm-ware, micro-code and the like, operating alone or in combination. Likewise, processing strategies may include multiprocessing, multitasking, parallel processing and the like.

Alternatively or additionally, dedicated hardware implementations, such as application specific integrated circuits, programmable logic arrays and other hardware devices, may be constructed to implement one or more of the control methods described herein. Applications that may include the apparatus and systems of various embodiments may broadly include a variety of electronic and computer systems. One or more embodiments described herein may implement functions using two or more specific interconnected hardware modules or devices with related control and data signals that may be communicated between and through the modules, or as portions of an application-specific integrated circuit. Accordingly, the present system may encompass software, firmware, and hardware implementations.

<FIG> represents a flow chart diagram for a method of controlling a drive train of a vehicle. As presented in the following sections, the acts may be performed using any combination of the components indicated in <FIG>. The following acts may be performed by the supervisory controller <NUM>, the power controller <NUM>, or a combination thereof. Additional, different, or fewer acts may be provided. The acts are performed in the order shown or other orders. The acts may also be repeated.

Data may be received that indicates a shaft input (Block <NUM>). The shaft input may be an input into a drive train control system. The data may be indicative of a torque of the shaft. The data may be data provided by a sensor, such as sensor <NUM> described with respect to <FIG>. From this data a shaft torque at various rotational shaft positions may be determined. For example, the sensor data may indicate a position of the shaft, and a mapping of torque output for the shaft at various positions may be referenced to determine the shaft output. The data may be indicative of other shaft inputs as well. For example, the data may be indicative of an angular velocity of the shaft.

An operational mode may be determined for various components in a drive train control system. One of these modes may be a vibration suppression mode. For example, an initial stage machine may have the option to operate in a vibration suppression mode (Block <NUM>). This vibration suppression mode may be operational to suppress vibrations of the shaft coupled with the initial stage machine. The initial stage machine may suppress vibrations by applying a torque to the shaft using electromagnetic forces generated by the initial stage machine. The amount of torque applied to the shaft may be determined by compensating for variations of a torque provided by the shaft throughout an angular rotation of the shaft. These variations in torque input may be determined using the obtained data indicative of shaft torque. Thus, the control of the initial stage machine may be based on the data indicative of shaft torque (Block <NUM>). This vibration suppression may be provided using the structures described above with respect to the initial stage machine <NUM> of <FIG>.

Also, a mid-stage stage machine may have the option to operate in an angular velocity differentiation mode (Block <NUM>). This angular velocity differentiation mode may be operational to change or vary an angular velocity between an input shaft coupled with the mid-stage machine and an output shaft coupled with the mid-stage machine. This variation in angular velocity may be achieved using an electromagnetic coupling of the input shaft and the output shaft across the mid-stage machine. For example, there may be no mechanical coupling between the input shaft and the output shaft, but the mid-stage machine may provide an electromagnetic coupling configured to allow for relative rotational movement of the input and output shafts based on a control of the mid-stage machine (Block <NUM>). This relative rotational movement may be provided using the structures described above with respect to the mid-stage machine <NUM> of <FIG>.

Also, a final stage machine may have the option to operate in drive mode (Block <NUM>). The final stage machine may be controlled to provide an output power to the output shaft (Block <NUM>). The desired output power may be provided by any technique. For example, the throttle <NUM> of <FIG> may indicate a desired drive power. This drive mode may be operational to provide additional drive torque to an output shaft coupled with the final stage machine. This drive power may be provided using the structures described above with respect to the final stage machine <NUM> of <FIG>.

Claim 1:
A vehicular system (<NUM>) comprising:
a crankshaft (<NUM>);
a drive shaft (<NUM>);
a plurality of electromagnetic machines (<NUM>, <NUM>, <NUM>) coupling the crankshaft to the drive shaft;
a power controller (<NUM>) electrically coupled to the plurality of electromagnetic machines (<NUM>, <NUM>, <NUM>) and configured to control power flowing through each electromagnetic machine of the plurality of electromagnetic machines (<NUM>, <NUM>, <NUM>);
a supervisory controller (<NUM>) communicatively coupled with the power controller (<NUM>) and configured to establish an operational mode for the power controller (<NUM>); and
a storage device (<NUM>) electrically coupled to the power controller (<NUM>) to store energy captured by the power controller (<NUM>);
wherein the plurality of electromagnetic machines (<NUM>, <NUM>, <NUM>) comprises:
a first electromagnetic machine (<NUM>) comprising a first stator armature (<NUM>) and a first engine rotor armature (<NUM>) driven by the crankshaft (<NUM>);
a second electromagnetic machine (<NUM>) comprising a second engine rotor armature (<NUM>) driven by the crankshaft (<NUM>) and a first drive rotor armature (<NUM>) rotatably coupled to the drive shaft (<NUM>); and
a third electromagnetic machine (<NUM>) comprising a second drive rotor armature (<NUM>) rotatably coupled to the drive shaft (<NUM>) and a second stator armature (<NUM>);
wherein the first and second stator armatures (<NUM>, <NUM>) are fixedly mounted to an internal combustion engine (<NUM>) that drives the crankshaft (<NUM>); and
wherein the first, second, and third electromagnetic machines (<NUM>, <NUM>, <NUM>) are disposed in a sequential arrangement in which respective armatures of each of the first, second, and third electromagnetic machines are coupled to one another radially;
characterised in that the supervisory controller (<NUM>) is configured to direct the power controller (<NUM>) to operate the plurality of electromagnetic machines (<NUM>, <NUM>, <NUM>) in a vibration suppression mode in which one or more of the electromagnetic machines (<NUM>, <NUM>, <NUM>) lower, suppress, or isolate torsional vibrations on the crankshaft (<NUM>).