Patent ID: 7717822
Filing Date: 2010-05-18
Classification: F16H,Y10T

Abstract:
1. A method of operating of a drivetrain of a motor vehicle having at least a drive motor and an automatic transmission with five shift elements, the method improving a shift speed of at least one of a successive upshift and a successive downshift, such that during a first upshift or a first downshift, at least one shift element, required for the respective successive upshift or the successive downshift, is prepared such that when a synchronization point of the first upshift or the first downshift in progress is reached, the successive upshift or the successive downshift can be immediately carried out, the method comprising the steps of: requiring three of the five shift elements be engaged and two of the five shift elements be disengaged, in each of a plurality of forward and reverse gears for transferring one of torque and force, and two respective consecutive upshifts or two respective consecutive downshifts are accomplished with at least some overlap; carrying out the first upshift or the first downshift, according to one of two alternatives, giving consideration to the successive upshift or the successive downshift, in a first alternative, a first shift element is disengaged and a second shift element is engaged and in a second alternative, the first shift element is engaged and the second shift element is disengaged; preparing the second shift element for one of engagement or disengagement, while the first upshift or the first downshift is being carried out while giving consideration to the successive upshift or the successive downshift, according to one of the two alternatives, in the first alternative, the second shift element is prepared for disengaging and a third shift element is prepared for engaging, and in the second alternative, the second shift element is prepared for engaging and the third shift element is prepared for disengaging; selecting the second shift element for one of engagement or disengagement, in the first alternative, from a minimum number of the five shift elements and, in the second alternative, from a maximum number of the five shift elements; one of engaging or disengaging the second shift element upon transition from the first upshift or the first downshift to the successive upshift or the successive downshift; and retaining at least one fourth shift element at least partially engaged while the first upshift or the first downshift is being carried out and while the successive upshift or the successive downshift is being carried out.