To meet the requirements of low fuel consumption, good driving performance, vehicle packaging constraint, and manufacturing feasibility, a new wet dual clutch transmission family has been developed by SAIC Motor. This paper will provide a design overview of the transmission architecture, main characteristics, key subsystems and control strategies. The paper will also provide an overview of the development process, and the fuel economy benefit to the vehicle.
The transmission family adopts compact layout of gears and shafts, wet dual clutch, hydraulic system for actuation of clutch and forks, integrated parking system, integrated fork and synchronizer system, etc. To achieve compact package target, a coaxial dual clutch with integrated damper system, two countershafts system, and optimized layout of gear system are adopted. The technical features for low fuel consumption include waved clutch plates, targeted cooling of wet clutch, optimized gear ratios, optimized control strategies. The technical features for high driving performance include optimized control on clutch pre-filling and clutch swap, close loop control on gear engagement, optimized control on different driving mode.
The newly developed 6-speed dual clutch transmission was applied to the new ROEWE550 vehicle equipped with 1.8L turbo and 1.8L natural aspirated gasoline engines. The vehicle was launched to China market in the middle of 2013. The newly developed wet DCT improves not only vehicle dynamic performance, but also fuel economy, with above 5% acceleration improvement and above 8% fuel consumption reduction.
