Tham khảo tài liệu 'advanced vehicle technology 2 episode 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | b Inner and outer race members freewheeling Fig. a and b Overrun freewheel sprag type clutch Fig. Characteristic performance curves of a three stage converter the fluid flow resistance around the torus passages. Subsequently efficiency drops off fairly rapidly with higher speed ratios compared to the three element converter Fig. . Polyphase hydrokinetic torque converter Figs and The object of the polyphase converter is to extend the high efficiency speed range Fig. of the simple three element converter by altering the vane or blade shapes of one element. Normally the stator is chosen as the fluid entrance direction changes with increased turbine speed. To achieve this the stator is divided into a number of separate parts in this case three each one being mounted on its own freewheel device built into its hub Fig. . The turbine exit and linear velocities VE and VL produce an effective resultant velocity VR which changes its direction of entry between stator blades as the impeller and turbine relative speeds 112 Fig. Multistage six element torque converter approach unity. It is this direction of fluid entering between the stator blades which in phases releases the various stator members. Initial phase Under stall speed conditions the fluid flow from the turbine to the stator is such as to be directed onto the concave rear side of all three sections of the divided stator blades thus producing optimum stator reaction for maximum torque multiplication conditions. Second phase As the turbine begins to rotate and the vehicle is propelled forwards the fluid changes its resultant direction of entry to the stator blades so that it impinges against the rear convex side of the first stator blades Si. The reaction on this member is now reversed so that it is released and is able to spin in the same direction as the input and output elements. The two remaining fixed stators now form the optimum blade curvatures for high efficiency. .
