Patent ID: 7130733

Claim:
A control method for effecting a gear shift in a stepped automatic transmission for transmitting power between two inertia components ( 1 ; 2 ) at distinct speed ratios, which inertia components at least represent an engine and a load respectively and which transmission comprises an input shaft ( 7 ) and an output shaft ( 8 ) with a first power transmission path ( 3 , H, 6 ) and a second power transmission path ( 3 , 4 , L, 5 , 6 ) provided there between, the said power transmission paths ( 3 , H, 6 ; 3 , 4 , L, 5 , 6 ), respectively being provided with a high clutch (H) having an adjustable torque transmitting capacity T H and a low clutch (L) having an adjustable torque transmitting capacity T L , comprising the steps of: determining a gear set input torque T in to be transmitted by the transmission in the direction from the input shaft ( 7 ) to the output shaft ( 8 ) and controlling the said torque transmitting capacities T H and T L in dependency on the gear set input torque T in to be transmitted such that: a) if T in ≧0 then T H =T in and T L =0 b) if T in <0 then T H =0 and T L =T in ′.