Patent ID: 7628016

Claim:
A method for multi-stage supercharging an internal combustion engine, said engine including a supercharging system, said method comprising steps of: routing fresh air through a low-pressure compressor ( 2 ); routing at least a portion of the compressed air stream through a high-pressure compressor ( 4 ) and the rest of the fresh air compressed in said low-pressure compressor ( 2 ) through a compressor bypass ( 5 ) around said high-pressure compressor ( 4 ); feeding all of said fresh air to the internal combustion engine ( 8 ), wherein said compressor bypass ( 5 ) is one of unblocked and closed by an automatic valve ( 6 ) as a function of the differential pressure across said high-pressure compressor ( 4 ), and said automatic valve ( 6 ) opening as soon as the pressure downstream of said valve ( 6 ) is lower than the pressure upstream of said valve ( 6 ) by a predetermined pressure differential which is a characteristic of said valve, said automatic valve ( 6 ) comprises a displacing body ( 17 ) received in a valve housing ( 16 ), said body comprising a movable first displacing part ( 18 ), a second displacing part ( 19 ) and a valve seat, said second displacing part ( 19 ) connected to said valve housing, said movable first displacing part ( 18 ) faces the inflow side of said valve and is movably guided by said second displacing part ( 19 ) to thereby one of closing and unblocking said compressor bypass ( 5 ), said displacing part including a spring element ( 22 ) for biasingly urging said first displacing part ( 18 ) onto said valve seat when said pressure differential is set to a value higher than zero and lower than 100 mbar, said automatic valve ( 6 ) further comprising a first plug ( 34 ) configured on said second displacing part ( 19 ) and a second plug ( 35 ) configured on said first displacing part ( 18 ), said second plug ( 35 ) is shaped so that it is received by a sleeve ( 25 ) and embraced by said sleeve ( 25 ) when said compressor bypass ( 5 ) is open, whereby when said first displacing part ( 18 ) moves toward said second displacing part, said second plug ( 35 ) is inserted into said sleeve and an air cushion is formed inside said sleeve ( 25 ) between said first plug ( 34 ) and said second plug ( 35 ) for damping the movement of said first displacing part ( 18 ).