Ratio control method for a continuously variable transmission

• US 20050107935A1
• Filed: 11/10/2004
• Published: 05/19/2005
• Est. Priority Date: 11/19/2003
• Status: Abandoned Application

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Herbster, Kai-Uwe, Iden, Oliver, Sporl, Peter
• Application Number:
  US10/985,296
• Publication Number:
  US 20050107935A1
• Time in Patent Office: Days
• US Class Current: 701/51
• CPC Class Codes: F16H 59/18 dependent on the position of the accelerator pedal
• CPC Class Codes: F16H 61/66254 controlling of shifting being influenced by a signal derived from the engine and the main coupling

Abstract

A method for adjusting a ratio of a continuously variable automatic transmission where a nominal ratio is determined according to an accelerator pedal signal value. The nominal ratio is determined according to a modified accelerator pedal signal. When the periodic curve of the accelerator pedal signal has a relative extreme value to the modified accelerator pedal signal, a starting value is assigned which is equal to this extreme value. Until the value of the modified accelerator pedal signal is again equal to the value of the unmodified accelerator pedal signal, the value of the modified accelerator pedal signal is determined by a transfer function.

Claims

1-6. -6. (canceled)

7. a ratio control method for a continuously variable automatic transmission having one adjustable variator for a motor vehicle actuatable by a prime mover, one electronic transmission control which comprises one control unit with one microcomputer which is connected with one or more of sensors and external control units, for detecting operating parameters and with adjusting means which, depending on control signals of the electronic transmission control adjusts on the variator, a certain ratio, to the control unit, is fed an accelerator pedal signal and, depending on the accelerator pedal signal in the control unit, one nominal ratio is determined, which is adjusted by the adjusting means in the variator, from the accelerator pedal signal in the control unit, a modified accelerator pedal signal is determined, the nominal ratio being determined according to the modified accelerator pedal signal, testing whether a periodic curve of the accelerator pedal signal has a relative extreme value and, in case the relative extreme value is detected, to the modified accelerator pedal signal is assigned, departing from a state in which the modified accelerator pedal signal is assigned is equal to an unmodified accelerator pedal signal, a starting value (f_start1) which is equal to the extreme value and that the value of the modified accelerator pedal signal is determined by a transfer function until the value of the modified accelerator pedal signal is again the same as the value of the unmodified accelerator pedal signal.

8. The method according to claim 7, wherein the modified accelerator pedal signal value determined by the transfer function is not greater than a sum of the unmodified accelerator pedal signal value and a maximum positive divergence and not smaller than a sum of the unmodified accelerator pedal signal value and a maximum negative divergence.

9. The method according to claim 7, wherein the modified accelerator pedal signal value determined by the transfer function is equal to the starting value until one of a maximum positive or a maximum negative divergence is reached or until the unmodified accelerator pedal signal value is again equal to the starting value.

10. The method according to claim 9, wherein the modified accelerator pedal signal value is suddenly set again equal to the unmodified accelerator pedal signal value when one of the maximum positive or the maximum negative divergence is reached.

11. The method according to claim 8, wherein the modified accelerator pedal signal value determined by the transfer function, beginning with the starting value, changes rigidly monotonously in direction of the unmodified accelerator pedal signal value until the modified accelerator pedal signal value is again equal to the unmodified accelerator signal value.

12. The method according to claim 11, wherein the modified accelerator pedal signal value drops linearly with a presettable gradient (α

) when the modified accelerator pedal signal value is greater than the unmodified accelerator pedal signal value and a difference between the two accelerator pedal signal values is smaller than the maximum positive divergence.