Abstract This paper describes the capabilities of a new two-motor plug-in hybrid-electric propulsion system developed for rear wheel drive. The PHEV system comprises a 2.0L turbocharged 4-cylinder direct- injected gasoline engine with the new hybrid transmission [ 1], a new traction power inverter module, a liquid-cooled lithium-ion battery pack, and on-board battery charger and 12V power converter module. The capability and features of the system components are described, and component performance and vehicle data are reported. The resulting propulsion system provides an excellent combination of electric-only driving, acceleration, and fuel economy. Introduction The Cadillac CT6 Plug-in Hybrid Electric Vehicle (PHEV) is designed for the top of the luxury segment range. The PHEV system, featuring an all-new rear wheel electric variable transmission (EVT) with two electric motor-generators designed exclusively for it, produces smooth, spirited acceleration and strong all-electric launch performance coupled with an impressive reduction in fuel consumption. This propulsion system integrates new technologies developed to achieve dynamic performance and efficiency at a new level for prestige luxury driving. The CT6 PHEV exceeds the requirements for electric-only performance and range to qualify as a New Energy Vehicle (NEV) in the Chinese market where the CT6 PHEV is being built and introduced. PHEV Propulsion System The Cadillac CT6 PHEV propulsion system includes an all-new rear wheel electric variable transmission with two integral electric motor-generators. The two-motor EVT drive unit is mated to a 2.0L turbo 4-cylinder engine with spark ignition, direct injection and variable valve timing technology. The use of a fully-integrated two-motor system provides smooth and seamless power through the entire driving range. An 18.4 kWh lithium-ion rechargeable energy storage system (RESS) is located in the rear of the vehicle between the rear seat and the trunk and is interfaced to the motors in the transmission using a traction power inverter module (TPIM) located in the engine compartment. Major components of CT6 PHEV system are shown in Figure 1, which also include an accessory power module (APM) and onboard charge module (OBCM). Figure 1. PHEV Propulsion System Components Vehicle Layout. Electric Variable Transmission The CT6 EVT [1] is the most recent addition to the GM electrification family of components. It meets the greater torque and power demands of the rear wheel drive (RWD) luxury and performance segment of the global market, building upon the same concepts in the drive system shared by the new Chevrolet V olt [ 2] and Malibu Hybrid. This new EVT is dedicated to electric propulsion and the full integration of electric propulsion for hybrid driving, with continuously variable transmission (CVT) action between the engine and the wheels to fully and smoothly optimize engine operation for efficiency and performance. CVT action is enabled by selectively using one of the two motor- generators (simply referred to as “motors”) as a generator to convert a fraction of the power from the engine into electricity and the other motor to convert that electric power back to mechanical form again. Meanwhile, planetary gearing carries most of the mechanical power from the engine to the wheels without conversion, amplifying the The GM RWD PHEV Propulsion System for the Cadillac CT6 Luxury Sedan2016-01-1159 Published 04/05/2016 Amanullah Khan, Timothy Grewe, Jinming Liu, Mohammad Anwar, Alan Holmes, and Richard Balsley General Motors Co. CITATION: Khan, A., Grewe, T., Liu, J., Anwar, M. et al., "The GM RWD PHEV Propulsion System for the Cadillac CT6 Luxury Sedan," SAE Technical Paper 2016-01-1159, 2016, doi:10.4271/2016-01-1159. Copyright © 2016 SAE International work of the motors. Clutches allow selection from four potential modes, each mode minimizing the amount of power converted and maximizing transmis