Zf Batavia L.l.c.

Andreas Schwenger

Wolfgang Danz

Andreas Piepenbrink

Ralf Vorndran

Friedrich Reiter

Within the scope of the method for adjusting the ratio value for a continuously variable transmission having a variator, a minimum contact pressure force P , and/or P is continuously calculated for the two variator discs on the basis of the actual ratio and of the actual torque to be transmitted and according to the calculated contact pressure minimum force the primary or the secondary disc is determined as controlled variable to be used for the variator ratio, the controlled variable being determined by a comparison of the required pressure values P or P with the calculated contact-pressure minimum value in a manner such that if P &lE;P , the controlled variable changes from the primary to the secondary side and if the condition P &lE;P is fulfilled, the secondary side changes to the primary side, the primary side being the controlled variable at the start of the method.

Method for adjusting the ratio of transmission in a continuous variable transmission

Within the scope of the method for regulating the rotational speed difference of a switchable frictional engagement control, specially of a clutch or brake, in the driving train of a motor vehicle by means of a control closed loop with the desired rotational speed difference as reference input and the actual rotational speed difference as controlled variable, together with the clutch pressure or brake pressure to be adjusted, at least one other controlled variable is used, wherein the closed loop comprises a linear governor and damping members (TP , TP , TP ) in a manner such that the time shift of the damped variable per reading step does not exceed a predetermined value so that the exciting of the closed loop remains within a stable range for controlling.

Speed difference regulation of a switchable frictional engagement control

Within the scope of the method for controlling the engine rotational speed via the torque converter lock-up clutch during the starting and stopping phases of a motor vehicle having a continuously variable transmission combined with other elements of the drive train, the closing and opening of the torque converter lock-up clutch are used as implicit function so as to ensure optimum comfort via the most asymptotic adjustment possible of the rotational speeds gradients of engine and turbine during starting and by a soft, defined separation of the speed characteristic curves of the engine and turbine during stopping. When the vehicle is standing still the forward clutch is moved into standstill disengaged mode so that the torque converter lock-up clutch can be fully closed.

Engine speed control via the torque converter lockup clutch of a continuously variable drive

In a method for controlling the multiplication for a continuously variable transmission with electrohydraulic control by means of a control loop having a linear PID controller with the specified multiplication of the variator iv_soll as command variable, the actual multiplication iv as regulating variable and the multiplication changing speed as correcting variable, the correcting variable delivered by the PID controller is limited to limiting values determined by the design for an upshift and downshift wherein said limiting values are calculated form the limits determined by construction and from the operating-point dependent limits determined by volume flow and the intersection of both admissible intervals determined by construction and by volume flow is defined as admissible multiplication changing speed range.

Method for determining adjusting speeds in a continuously variable transmission

Within the scope of the method for including the temperature in the calculation of the definite, operating-point dependent maximum and minimum adjustment speeds in a continuously variable belt-drive transmission, the actual limiting values for the maximum possible adjustment gradient are continuously calculated in every operating state by a physical-mathematical pattern wherein the hydraulic routes of the variator, the clutches integrated in the transmission and the lubrication are modeled as laminar inserts and the route of the control unit leakage as coupled laminar and turbulent hydraulic transmission elements.

Method of calculating for the speed control of a CVT

Within the scope of the method for ratio control of a continuously variable automatic transmission of a motor vehicle by means of a control loop structure which contains a non-linear compensation member for the variator and controllers for the pressures of both hydraulic routes of the variator pulleys and the variator routes, the control loop structure contains an interference variable observer which generates an interference force F that reproduces the pattern precision wherein the interference force together with the set value for the adjustment gradient which is limited as result of external standards, forms the compensation member.

Method for ratio controlling or speed controlling

A method for ratio control for a continuously variable belt drive transmission with electrohydraulic control by means of a control loop with a linear PID controller with the theoretical ratio of the variator iv_theor. as command variable, the actual ratio iv as control variable and the ratio-change speed as correcting variable wherein the correcting variable delivered by the PID controller is limited to limit values subject to the design for an upshift and a downshift, a correction member is used which, taking into consideration internal and external system variables, corrects with the aid of a physicomathematical pattern the pattern error generated wherein to the equation based on the physicomathematical pattern

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Friedrichshafen, Germany

Andreas Schwenger