A METHOD FOR CONTROLLING A POWERTRAIN SYSTEM DURING UPSHIFTING

The invention relates to a method () for controlling a powertrain system () of a vehicle () during gear upshifting, said powertrain system comprising: an internal combustion engine system () comprising an internal combustion engine () configured to output a rotational speed (W) via an engine output shaft (); a transmission arrangement () having a number of gear stages to obtain a set of gears, the transmission arrangement being operatively connected to the internal combustion engine via a transmission input shaft () and further having a transmission output shaft () for providing a rotational speed to one or more drive wheels () of the vehicle; the method comprising the steps of: operating () the engine in a four-stroke operation to provide engine rotational speed output via the engine output shaft; receiving () an indication of an intended upshifting from a gear of the set of gears to a higher gear of the sets of gears; reducing () the rotational speed of the engine output shaft by adjusting the operation of the engine from the four-stroke operation to a two-stroke braking operation; and, when said engine is in the two-stroke braking operation, performing () the intended upshifting from said gear of the set of gears to said higher gear of the sets of gears.