A vehicle is operable in three modes of operation. The vehicle includes a first electromagnetic device, a second electromagnetic device electrically coupled to the first electromagnetic device, and an engine coupled to the first electromagnetic device and configured to drive the first electromagnetic device to provide electrical energy. In each of the three modes of operation, whenever the engine drives the first electromagnetic device to provide the electrical energy, the first electromagnetic device operates without providing the electrical energy to an energy storage device.

A method of operating a first electric machine and a second electric machine in a vehicle drive includes operating the vehicle drive in a first operating mode by operating the first electric machine to regulate electrical power at a bus to maintain a first voltage on the bus and operating the second electric machine to consume electrical power from the bus. The method includes operating the vehicle drive in a second operating mode by operating the first electric machine to consume electrical power from the bus and operating the second electric machine to regulate electrical power at the bus to maintain a second voltage on the bus. A sum of the electrical power regulated by the first electric machine, the electrical power losses, and the electrical power consumed by the second electric machine is zero in the first operating mode and in the second operating mode.

A powertrain system includes a transmission, torque generating device, load coupled to a drive axle, a final drive unit in meshed gear engagement with the output shaft and the drive axle, and a controller. A requested output torque is processed using an open-loop lash state model populated with a capped output torque request table and a lash closure rate estimate table respectively providing a capped torque value and an estimated lash closure rate. Output speed is determined using a plant model, the capped torque value, and the estimated lash closure rate. The powertrain is controlled during the transition using the output speed. A lash angle may be calculated from the closure rate using an integrator logic block. A calibrated lash offset profile may be determined using the lash angle, and a reference speed may be generated using the lash offset profile.

A vehicle drive includes a gear set, a first motor/generator coupled to the gear set, a second motor/generator at least selectively rotationally engaged with the gear set, an engine at least selectively coupled to the gear set and selectively coupled to the second motor/generator, and a clutch configured to selectively engage the second motor/generator to the engine. The first motor/generator and the second motor/generator are electrically coupled without an energy storage device configured to at least one of (a) provide electrical energy to the first motor/generator or the second motor/generator to power the first motor/generator or the second motor/generator and (b) be charged by electrical energy from the first motor/generator or the second motor/generator.

A method of operating a first electric machine and a second electric machine in a vehicle drive includes operating the vehicle drive in: a first operating mode by operating the first electric machine in a voltage mode and the second electric machine in a torque mode; and a second operating mode by operating the first electric machine in the torque mode and the second electric machine in the voltage mode.

A vehicle drive includes a gear set, a first motor/generator coupled to the gear set, a second motor/generator at least selectively rotationally engaged with the gear set, an engine at least selectively coupled to the gear set and selectively coupled to the second motor/generator, and a clutch configured to selectively engage the second motor/generator to the engine. The first motor/generator and the second motor/generator are electrically coupled without an energy storage device configured to at least one of (a) provide electrical energy to the first motor/generator or the second motor/generator to power the first motor/generator or the second motor/generator and (b) be charged by electrical energy from the first motor/generator or the second motor/generator.

A vehicle drive includes a gear set, a first motor/generator coupled to a sun gear of the gear set, a second motor/generator selectively coupled to at least one of (a) a planetary gear carrier of the gear set and (b) a ring gear of the gear set, an engine coupled to the ring gear of the gear set and selectively coupled to the second motor/generator, and a clutch configured to selectively engage the second motor/generator to the engine. The first motor/generator and the second motor/generator are electrically coupled without an energy storage device configured to at least one of (a) provide electrical energy to the first motor/generator or the second motor/generator to power the first motor/generator or the second motor/generator and (b) be charged by electrical energy from the first motor/generator or the second motor/generator.

A vehicle is operable in three modes of operation. The vehicle includes a first electromagnetic device, a second electromagnetic device electrically coupled to the first electromagnetic device, and an engine coupled to the first electromagnetic device and configured to drive the first electromagnetic device to provide electrical energy. In each of the three modes of operation, whenever the engine drives the first electromagnetic device to provide the electrical energy, the first electromagnetic device operates without providing the electrical energy to an energy storage device.

A method of operating a first electric machine and a second electric machine in a vehicle drive includes operating the vehicle drive in: a first operating mode by operating the first electric machine in a voltage mode and the second electric machine in a torque mode; and a second operating mode by operating the first electric machine in the torque mode and the second electric machine in the voltage mode.

A vehicle is operable in three modes of operation. The vehicle includes a first electromagnetic device, a second electromagnetic device electrically coupled to the first electromagnetic device, and an engine coupled to the first electromagnetic device and configured to drive the first electromagnetic device to provide electrical energy. In each of the three modes of operation, whenever the engine drives the first electromagnetic device to provide the electrical energy, the first electromagnetic device operates without providing the electrical energy to an energy storage device.