Patent Number: 6,311,113

Title: Control method for adjusting the transmission ratio of a CVT

Abstract: 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 ##EQU1## a correction term ##EQU2## is added and as standard for the ratio gradients the following equation is used: ##EQU3##

Inventors: Danz; Wolfgang (Friedrichshafen, DE), Piepenbrink; Andreas (Meersburg, DE), Schwenger; Andreas (Friedrichshafen, DE)

Assignee: ZF Batavia, L.L.C.

International Classification: F16H 61/66 (20060101); F16H 61/662 (20060101); F16H 061/00 (); F16H 059/00 ()

Expiration Date: 10/30/2018