In Shanghai, China, General Motors announced today that it will swiftly and extensively release its high-performance nine-speed auto transmission which will be debuting later this year with a large number of SUVs. The cutting-edge transmission technology improves efficiency and enhances performance and is expected to be adopted in 13 different models from Chevrolet, Cadillac, and Buick by 2020. It was a collective global development and was thoroughly tested globally—even in China. The newly developed nine-speed transmission has a 2pc higher fuel efficiency compared to its six-speed transmission counterpart. It implements a start/stop technology which saves fuel in typical traffic situations by shutting the engine down.
China GM’s VP, Global Propulsion Systems; Michael Carman said “GM has made it a priority to bring our company’s most advanced global technologies to China to benefit our local customers. This is enabling us to reduce emissions and maximize the fuel economy of our current and next generation of vehicles.” The 9-speed auto transmission features an overall ratio of 7.6:1, a first gear of 4.69 and for small-Rpm highway cruising it has a top gear of 0.62. This helps to optimize acceleration, minimize engine noise, and optimize fuel consumption while cruising to give you that balanced finesse and performance which you will all love at any speed.
The 9-speed automatic transmission was developed to address the small packaging needs of transversal propulsion systems and it also features an on-axis design which lines the gears with the crankshaft. This is GM’s first use of a one-way clutch that offers selection. These features aim to minimize package size making it loosely equivalent in size to the 6-speed transmission. For accurate and seamless shifts, a special procedure is employed to select the torque converter, gear sets, and clutches. Five epicyclic gear sets are employed having four parked clutches and three rotary clutches which saves on space. Gears transition from the 2nd to 9th gear ratios with clear-cut clutch-to-clutch changes—the clutch is connected to one gear while simultaneously disengaging from another gear.