battery. GM is not part of this expanded partnership, and has not announced plans to develop a hybrid RWD system for cars. It was reported in July 2009, however, that after the upcoming introductions of two-mode versions of the BMW X6 globally and the Mercedes-Benz M class only in the United States, the joint venture would be dissolved. Daimler indicated that it wants to avoid investing in aftersales and service for a vehicle which will only be produced in small quantities, and will instead concentrate on modular hybrid building blocks with scalable lithium-ion batteries, based on the hybrid drive developed for the S-class and 7 Series sedans in another joint venture with BMW and auto supplier Continental AG. Technology The technology is referred to as "two-mode" hybrid transmission due to the ability to extend the abilities of both electrical and mechanical paths of power. The two modes of operation are: Input-split mode — The rotational speed of the 2nd motor (M/G 2) is always proportional to the output shaft, while the 1st motor (M/G 1) is not proportional to the input shaft. The 2nd electric motor direct drive the output, and it is possible to drive the vehicle without combustion engine. The power flow is split only at the input, that is why it is called Input-split. At low speeds, the vehicle can move with either the electric motor/generators, the internal combustion engine, or both, making it a so-called full hybrid. All accessories will still remain functioning on electric power, and the engine can restart instantly if needed. In this mode, one of the motor/generators (M/G 1) acts as a generator, while the other operates as a motor (M/G 2). This mode is operational for the two continuously variable ranges (input split and compound split) of the transmission. Compound-split mode — The rotational speed of the 2nd motor (M/G 2) is not proportional to the output shaft, like the 1st motor (M/G 1) is not proportional to the input shaft. The power flow is split at the input and at the output, that is why it is called Compound-split. It is impossible to drive the vehicle without combustion engine. This mode begins at the point where one of the motor/generators reaches zero speed; at this point some clutches within the system engage while others disengage to alter the physical configuration of the transmission, and the velocity is Vshift. Immediately after