The invention relates to a generator set, particularly applicable to the range extender in an electrical drive motor vehicle (electrical vehicles). In the generator set, a combustion motor and an electric mechanical energy converter are least partly enclosed by the housing. With the housing, the noise emission to the environment can be cut down. A combustion motor of the generator set comprises at least an air inlet apparatus, an exhaust gas discharging apparatus, and a transmission shaft. According to the invention, the airflow flows in the housing via the air inlet apparatus. The airflow can be used to cool the combustion motor. The airflow basically enters the housing in a broadwise manner and enters the combustion motor in angle Alpha that can be regulated in advance relative to the transmission shaft.