Abstract: A hydraulic system for a mobile work vehicle is configurable in a hybrid mode and a hydrostatic mode. The hydraulic system includes a pump/motor, a propel circuit, a pump, a hydraulic accumulator, and an accessory circuit. The pump/motor is adapted to exchange power with a drive train of the mobile work vehicle. The propel circuit is adapted to exchange hydraulic fluid power with the pump/motor. The pump is adapted to transfer power from a prime mover of the mobile work vehicle to the propel circuit. The hydraulic accumulator is adapted to exchange hydraulic fluid power via an accumulator isolation valve with the propel circuit when the hydraulic system is configured in the hybrid mode. The accessory circuit is adapted to receive hydraulic fluid power from the hydraulic accumulator, at least when the hydraulic system is configured in the hydrostatic mode and the accumulator isolation valve is closed.

Abstract: A method of propelling a vehicle with a hybrid mode and a hydrostatic mode includes determining if a current propulsion mode is hybrid and if a selected mode is hydrostatic. A first transition mode is entered if the selected mode is hydrostatic and the current mode is hybrid. An engine-pump displacement target is set in the first transition mode. The method may include determining if the current mode is hybrid, hydrostatic, or a no-propulsion mode and if the selected mode is hybrid, hydrostatic, or no-propulsion. The engine-pump displacement target may be matched to a system consumption and an accumulator isolation valve closed when an engine-pump output matches the system consumption in the first transition mode. The method may include entering a second transition mode if the selected mode is hybrid and the current mode is hydrostatic.

Abstract: A hydraulic circuit architecture for a work vehicle includes a pump, a work circuit, a propel circuit, and a circuit selector. The work circuit is connected to an actuator for driving a work component of the work vehicle. The propel circuit includes a motor that is adapted to be connected to a drive train of the work vehicle. The propel circuit also includes an accumulator. The circuit selector selectively connects the pump to the work circuit and the propel circuit. The hydraulic circuit architecture is operable in a first mode and a second mode. In the first mode, the propel circuit is connected to the pump and the work circuit is disconnected from the pump. In the second mode, the work circuit is connected to the pump and the propel circuit is disconnected from the pump. When the hydraulic circuit architecture is in the second mode, stored energy from the accumulator can be used to drive the motor to cause propulsion of the work vehicle.

Abstract: A hydraulic system for a mobile work vehicle is configurable in a hybrid mode and a hydrostatic mode. The hydraulic system includes a pump/motor, a propel circuit, a pump, a hydraulic accumulator, and an accessory circuit. The pump/motor is adapted to exchange power with a drive train of the mobile work vehicle. The propel circuit is adapted to exchange hydraulic fluid power with the pump/motor. The pump is adapted to transfer power from a prime mover of the mobile work vehicle to the propel circuit. The hydraulic accumulator is adapted to exchange hydraulic fluid power via an accumulator isolation valve with the propel circuit when the hydraulic system is configured in the hybrid mode. The accessory circuit is adapted to receive hydraulic fluid power from the hydraulic accumulator, at least when the hydraulic system is configured in the hydrostatic mode and the accumulator isolation valve is closed.

Abstract: A method of propelling a vehicle with a hybrid mode and a hydrostatic mode includes determining if a current propulsion mode is hybrid and if a selected mode is hydrostatic. A first transition mode is entered if the selected mode is hydrostatic and the current mode is hybrid. An engine-pump displacement target is set in the first transition mode. The method may include determining if the current mode is hybrid, hydrostatic, or a no-propulsion mode and if the selected mode is hybrid, hydrostatic, or no-propulsion. The engine-pump displacement target may be matched to a system consumption and an accumulator isolation valve closed when an engine-pump output matches the system consumption in the first transition mode. The method may include entering a second transition mode if the selected mode is hybrid and the current mode is hydrostatic.

Abstract: A hydraulic circuit architecture for a work vehicle includes a pump, a work circuit, a propel circuit, and a circuit selector. The work circuit is connected to an actuator for driving a work component of the work vehicle. The propel circuit includes a motor that is adapted to be connected to a drive train of the work vehicle. The propel circuit also includes an accumulator. The circuit selector selectively connects the pump to the work circuit and the propel circuit. The hydraulic circuit architecture is operable in a first mode and a second mode. In the first mode, the propel circuit is connected to the pump and the work circuit is disconnected from the pump. In the second mode, the work circuit is connected to the pump and the propel circuit is disconnected from the pump. When the hydraulic circuit architecture is in the second mode, stored energy from the accumulator can be used to drive the motor to cause propulsion of the work vehicle.