The present invention relates to a supercharged internal combustion engine having a compressor. The present invention provides a method and a system for a turbocharger. In one example, a turbochargercomprises one or more than one cooling devices for cooling the compressor. The cooling device comprises ventilation systems arranged in a wheel and a shaft of the compressor, and the ventilation system is configured to allow ambient air to be flowed into the shaft without being compressed.