POWERTRAIN SYSTEM

A powertrain system includes a control device configured, where an engine speed at the time of detection of an acceleration request with a high acceleration request index value is lower than a specific engine speed, to: set the specific engine speed as an initial target engine speed for an acceleration associated with the acceleration request; and in a first acceleration time period before reaching the initial target engine speed, control an internal combustion engine in accordance with a first target engine power based on the initial target engine speed and supply, to an electric motor, a battery power corresponding to a difference obtained by subtracting the first target engine power from a required vehicle power. The specific engine speed is a value predetermined as a lower limit value of an engine speed range in which engine sound of the internal combustion engine is heard inside the vehicle.