pressure the compressor bypass opening as soon as the pressure downstream from the high pressure compressor is lower than the pressure upstream of the high pressure compressor application_number US 19996805 A description fig1 is a flow diagram of a two stage supercharging system fresh air 1 is delivered to a low pressure compressor 2 in low pressure compressor 2 the air is compressed to a pressure above the ambient pressure since the air heats as it is being compressed in the embodiment shown in fig1 the low pressure compressor is followed by a first heat exchanger 3 in which the fresh air 1 compressed by low pressure compressor 2 is cooled the heat exchanger 3 can also be omitted however the fresh air 1 compressed in low pressure compressor 2 is delivered to a high pressure compressor 4 in high pressure compressor 4 the air compressed in low pressure compressor 2 is compressed further after the fresh air 1 has been compressed in high pressure compressor 4 the fresh air 1 is delivered to an internal combustion engine 8 internal combustion engine 8 can be operated on either a self ignition or a spark ignition principle the fresh air 1 is preferably cooled in a second heat exchanger 7 before entering the internal combustion engine 8 to keep the volume flow through high pressure compressor 4 from becoming greater than the maximum possible delivery capacity a compressor bypass 5 branches off in front of high pressure compressor 4 compressor bypass 5 is closed by a self actuating valve 6 self actuating valve 6 is implemented for example as a check valve that opens as soon as.