Method for fast change of gears in a vehicle comprising a hybrid driveline

Abstract

A method for shifting in a vehicle () with a hybrid powertrain (), the powertrain includes: a combustion engine (), an electric machine (), a gearbox () with an input shaft () and a main shaft (), wherein the combustion engine () and the electric machine () are connected to the input shaft (); and a lay shaft (), via gear sets (and) is connected to the input shaft () and the main shaft (), so that they form a split gear unit () and a main gear unit (). The method has the steps: a) to bring the main gear unit () into a substantially zero torque state, b) in the event the input shaft () and the lay shaft () must both be accelerated or decelerated: to initiate synchronization of the speed of the lay shaft () with, on the one hand, the speed of the input shaft (), and, on the other hand, the speed of the main shaft (), at a joint first point in time (t), c) to engage a gear in the split gear unit () when the speed of the lay shaft () has been synchronized with the speed of the input shaft () at a second point in time (t), and d) to engage a gear in the main gear unit () when the speed of the lay shaft () has been synchronized with the speed of the main shaft () at a third point in time (t). Also a hybrid powertrain () and a vehicle (), as well as a computer program (P) and a computer program product are disclosed, which perform the method.