Abstract: An electric torque converter has a torque converter input member connected to the first node of a differential gear set representable by a lever diagram having first, second, and third nodes. A motor/generator is connected to the second node. The third node is connected to an input member of a transmission gearing arrangement. A brake is selectively engagable to ground the first node to a stationary member. Engagement of the brake provides a regenerative braking mode and an electric-only driving mode, with the motor/generator connected to the transmission gearing arrangement through the differential gear set. Various clutches may be provided for lock-up or selective connection of the engine, including arrangements which reduce motor/generator torque required for engine starting while in electric-only driving. A method of operating a vehicle maintains the engine speed at an optimum level to the extent possible given battery charge levels and operator commands.

Abstract: A method is provided for transitioning from an initial to a final transmission mode in an electrically variable transmission (EVT), and includes transitioning to an intermediate mode having an additional speed degree of freedom (DOF), changing a transmission ratio, and engaging a clutch to shift to the final mode. The modes include input and compound split, fixed gear ratio, and electric torque converter (ETC), with and without input from an engine. Output torque is maintained by adjusting a charge on an energy storage device. A brake grounds an input member of the EVT. The EVT has the input member, an output member, a stationary member, and first and second motor/generators. An algorithm transitions between modes by releasing at least one clutch to transition to a mode having an extra speed degree of freedom (DOF), and utilizing the extra speed DOF to change the ratio of the EVT.

Abstract: A hybrid powertrain includes a control unit that regulates electric power interchange an energy storage device and a motor/generator for causing selective torque generation by the motor/generator and for controlling engagement of torque-transmitting mechanisms. The control unit is configured to place the torque-transmitting mechanism in slipping engagement to launch the vehicle and thereby decouple a fixed relationship between engine torque and motor/generator torque or between engine torque and torque at the output member. A method of operating a hybrid vehicle powertrain is also provided.

Abstract: A vehicle powertrain for a hybrid vehicle includes an electronically variable transmission (EVT) with an input member to receive mechanical rotary power from the engine, an output member to provide mechanical rotary power to a vehicle powertrain to propel the vehicle, and an EVT gear train configured to selectively and operatively couple the input member to the output member. The EVT further includes first and second motor/generators driveably coupled to the gear train. A selectively engageable input brake mechanism is provided to create a reaction torque for the motor/generators thereby enabling the motor/generators to be used with additive power for electric propulsion or regenerative braking. The input brake improves electrical power to mechanical power conversion efficiency by reducing power circulation when the EVT is operated in electric drive, engine off mode.

Abstract: An electrically variable transmission (EVT) is provided with input member and output member, first and second motor/generators, a first and a second planetary gear set, and a final drive gearset. Two torque-transmitting mechanisms that are selectively engagable alone or in different combinations to establish an electric-only operating mode, an input split mode, a compound split mode, and a neutral mode. The first torque-transmitting mechanism may be configured as a one-way clutch in parallel with a friction clutch or a dog clutch, or configured as a lockable one-way clutch. A vehicle having the EVT may be driven electrically using one or both motor/generators, up to a maximum speed of the motor/generators. There are no slipping clutches when operated in an electric-only operating mode, and the engine provides most of the power for high-speed cruising. The EVT can transition from input split mode to compound split mode by synchronous shift.

Abstract: An electrically-variable transmission is provided with first and second motor/generators and three planetary gear assemblies. At least one of the planetary gear assemblies is a planetary gear assembly having multiple planetary gear sets. As a result, the gears for the planetary gear assembly can be represented on multiple radial planes. Each of the planetary gear assemblies has continuous interconnections, and selective connections via a plurality of torque-transmitting mechanisms, that provide three forward electrically-variable modes. Preferably, the planetary gear assemblies are connected to one another in such a manner as to allow shifting between one of the electrically-variable modes to occur at a point offset from a mechanical power flow of the transmission. This decreases the maximum power output required from the motor/generators.

Abstract: An electrically-variable transmission is provided with input member and output member, first and second motor/generators, a first planetary gear set and a final drive gearset. Two or three torque-transmitting mechanisms that are selectively engagable alone or in different combinations to establish at least one forward electric-only operating mode including a series mode, an output split mode, and at least one neutral mode including a purely neutral mode and a neutral battery charge mode. The transmission optionally includes a one-way clutch selected from the group of friction clutch and dog clutch, or is a lockable one-way clutch, for enabling low loss forward operation, regenerative braking functionality, and/or reverse vehicle operation.

Abstract: A single mode, compound-split transmission is provided having two mechanical power paths. One mechanical path is primarily active at low speed ratios with the other path being primarily active in high speed ratios. A reduction ratio is available in the path employed for high speed ratios, reducing electrical path power requirements. Additionally, the reduction ratio, allows both of two motor/generators to be of a relatively low torque design.

Abstract: An electrically variable transmission family having low-content, low-cost electrically variable transmission mechanisms including three differential gear sets, a battery, three interconnecting members, two electric machines serving interchangeably as motors or generators and five or six selectable torque-transfer devices. The selectable torque transmitting devices are engaged to yield an EVT with a continuously variable range of speeds and five fixed speed ratios, including four mechanically fixed forward speed ratios and one reverse speed ratio. The torque transmitting devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.

Abstract: An electrically variable transmission family having low-content, low-cost electrically variable transmission mechanisms including three differential gear sets, a battery, two electric machines serving interchangeably as motors or generators and five selectable torque-transfer devices. The selectable torque transmitting devices are engaged to yield an EVT with a continuously variable range of speeds and five fixed speed ratios, including four mechanically fixed forward speed ratios and one reverse speed ratio. The torque transmitting devices and the first and second motor/generators are operable to provide six operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, series reverse mode, launch modes, continuously variable transmission range mode, and fixed ratio mode.

Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including three differential gear sets, a battery, two electric machines serving interchangeably as motors or generators and four or five selectable torque-transfer devices. The selectable torque transmitting devices are engaged to yield an EVT with a continuously variable range of speeds and five fixed speed ratios, four mechanically fixed forward speed ratios and one reverse speed ratio. The torque transmitting devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.

Abstract: A control system for a hybrid powertrain determines operator demands, a powertrain operating state, and operating conditions based upon the inputs; selects an operating strategy based upon the operator demands, the powertrain operating state, and the operating conditions; determines a preferred powertrain operating state; and controls the powertrain to the preferred powertrain operating state based upon the selected operating strategy, the operator demands and the operating conditions.

Abstract: An electrically-variable transmission is provided with input member and output member, first and second motor/generators, a first planetary gear set and multiple additional planetary gear sets as well as at least four torque-transmitting mechanisms that are selectively engagable alone or in different combinations to establish a reverse electrically-variable operating mode, at least three forward electrically-variable operating modes, including two low range forward electrically-variable modes and a high range forward electrically-variable mode

Abstract: An electrically-variable transmission is provided with first and second motor/generators and three planetary gear sets. The planetary gear sets have continuous interconnections, and selective connections via a plurality of torque-transmitting mechanisms, that provide three forward electrically-variable modes. Preferably, the planetary gear sets are characterized by effective gear ratios such that a substantially equal maximum torque is required from each of the motor/generators during the three forward electrically-variable modes for a given torque on the input member. This allows the first and second motor/generators to be substantially equal in size.

Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including three differential gear sets, a battery, two electric machines serving interchangeably as motors or generators and five selectable torque-transfer devices. The selectable torque transmitting devices are engaged to yield an EVT with a continuously variable range of speeds and five fixed speed ratios, including four mechanically fixed forward speed ratios and one reverse speed ratio. The torque transmitting devices and the first and second motor/generators are operable to provide six operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, series reverse mode, launch modes, continuously variable transmission range mode, and fixed ratio mode.

Abstract: A vehicle powertrain for a hybrid vehicle includes an electronically variable transmission (EVT) with an input member to receive mechanical rotary power from the engine, an output member to provide mechanical rotary power to a vehicle powertrain to propel the vehicle, and an EVT gear train configured to selectively and operatively couple the input member to the output member. The EVT further includes first and second motor/generators driveably coupled to the gear train. A selectively engageable input brake mechanism is provided to create a reaction torque for the motor/generators thereby enabling the motor/generators to be used with additive power for electric propulsion or regenerative braking. The input brake improves electrical power to mechanical power conversion efficiency by reducing power circulation when the EVT is operated in electric drive, engine off mode.

Abstract: A hybrid powertrain system for a vehicle includes an engine and a transmission. The transmission includes a transmission input member, first and second electric machines, first and second planetary gear sets, and a plurality of selectively engageable torque transfer devices enabling configuring the powertrain in variously to operate in electric drive, electrically variable, fixed gear and neutral charging operating states.

Abstract: A vehicle has a powertrain including an engine and at least one electric machine. A method for maximizing range capability of the vehicle while operating in an electric vehicle operating state includes determining an incipient electric vehicle operating state of the powertrain, setting a preferred charge/discharge rate of an electric energy storage device to a maximum charging rate, and controlling the powertrain to an operating state including an engine state that is ON to effect charging the electrical energy storage device based on the maximum charging rate.

Abstract: The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including three differential gear sets, a battery, two electric machines serving interchangeably as motors or generators and four or five selectable torque-transfer devices. The selectable torque transmitting devices are engaged to yield an EVT with a continuously variable range of speeds and five fixed speed ratios, four mechanically fixed forward speed ratios and one reverse speed ratio. The torque transmitting devices and the first and second motor/generators are operable to provide five operating modes in the electrically variable transmission, including battery reverse mode, EVT reverse mode, reverse and forward launch modes, continuously variable transmission range mode, and fixed ratio mode.

Abstract: An electrically variable transmission includes a power source, three differential gear sets, first and second motor/generators each connected to at least one of the gear sets, and torque-transmitting mechanisms. An input member transfers power from the power source through the differential gear sets to an output member. The torque-transmitting mechanisms are selectively engageable to provide an input-split first electrically variable mode having equal forward and reverse speed ratios for given input speeds and to provide substantially equal fixed forward and reverse speed ratios.