Method and arrangement for actuating an automatic transmission of a motor vehicle

Abstract

The invention proceeds from an automatic transmission wherein upshift and downshift operations are triggered in dependence upon first and second signals for adjusting transmission ratios. The first signal is representative of the transmission output rpm and/or the engine rpm and/or the transmission input rpm and the second signal is representative of the driver command. These upshift and downshift operations take place with a hysteresis which is typical for the particular upshift and downshift operation. According to the invention, the hysteresis has a time-dependent component. Thus, a time-dependent hysteresis is defined in addition to the hysteresis mentioned above which is a basic hysteresis between upshifting and downshifting. The time-independent basic hysteresis can then be selected to be very small for adjusting the gear optimal for the particular operating condition. This affords the advantage that, for example, after an upshift, the load threshold for a pendular downshift into the previous gear is increased for a short time or, after an upshift, the load threshold for a pendular upshift into the previous gear is reduced for a short time.

Dependencies are inferred from the claim text.