In order to provide a separating device which has a simple design and is operable reliably and efficiently, it is proposed that the separating device comprises the following: at least one separating body for separating the impurities; an ejector device for producing a suction effect on an exit side of the at least one separating body; a supply device for supplying a drive medium to the ejector device, wherein, by means of the supply device, selectively a) compressed supply air from a supply air tract of the combustion engine, b) exhaust gas from an exhaust gas tract of the combustion engine and/or c) a mixture of compressed supply air and exhaust gas is suppliable as drive medium to the ejector device.