Abstract: A multi-mode electro-mechanical variable speed transmission capable of providing two power split operation modes and at least one fixed output-to-input speed ratio operation mode. The transmission includes an input shaft, an output system, at least one planetary gear set having at least a first, second and third co-axial rotatable components, two electric machines, and at least one torque transfer device. The first co-axial rotatable component couples to the first electric machine with a constant speed ratio; the second co-axial rotatable component couples to the output system with a constant speed ratio; and the third co-axial rotatable component couples to the input shaft with a constant speed ratio; the second electric machine selectively couples to two different co-axial rotatable components of the planetary gear set with two different speed ratios.

Abstract: A multi-mode electro-mechanical variable speed transmission capable of providing two power split operation modes and at least one fixed output-to-input speed ratio operation mode. The transmission includes an input shaft, an output system, at least one planetary gear set having at least a first, second and third co-axial rotatable components, two electric machines, and at least one torque transfer device. The first co-axial rotatable component couples to the first electric machine with a constant speed ratio; the second co-axial rotatable component couples to the output system with a constant speed ratio; and the third co-axial rotatable component couples to the input shaft with a constant speed ratio; the second electric machine selectively couples to two different co-axial rotatable components of the planetary gear set with two different speed ratios.