System and method for controlling a powertrain system of a vehicle

A computer-implemented method for controlling a powertrain system of a vehicle/, the powertrain system comprising an internal combustion engine connectable to one or more drive wheels, the powertrain system being operable in a number of operational modes, including at least a freewheeling mode, in which an output shaft of the engine is non-rotating, and the engine is disconnected from the one or more drive wheels, wherein the method comprises:

• predicting, by processing circuitry of a computer system, fuel saving in response to a potential up-coming freewheeling mode period, the fuel saving being determined from engine-idle fuel consumption data;
• predicting, by processing circuitry of the computer system, a loss of kinetic energy for restarting the engine in the freewheeling mode using a controllable clutch;
• predicting, by processing circuitry of the computer system, fuel consumption needed to regain the predicted loss of kinetic energy;
• comparing, by processing circuitry of the computer system, the predicted fuel saving with the predicted fuel consumption;
• determining, by processing circuitry of the computer system, to control the powertrain system into the freewheeling mode based on the comparison;
• and
• controlling, by processing circuitry of the computer system, the powertrain system into the freewheeling mode.