Patent ID: 7601190

Claim:
An air filter system ( 1 ) for reciprocating piston internal combustion engines, comprising a fresh air supply line ( 2 ) with an air inlet, a filter housing ( 3 ) with an upper housing half ( 12 ) and lower housing half, said housing ( 3 ) including a filter element ( 4 ), a clean air outlet opening ( 7 ) with an adjoining clean air line ( 8 ) which opens into an intake manifold ( 9 ) of the reciprocating piston internal combustion engine, and means ( 13 ) for damping air intake noises, said means ( 13 ) for damping air intake noises being a sheet ( 13 ) configured and arranged adjacent to, and clamped against, the housing half ( 12 ) of the filter housing ( 3 ) opposite the clean air outlet opening ( 7 ) whereby the intake noise is absorbed by sudden changes in impedance of the inlet air resulting in relative frictional movement of the sheet ( 13 ) relative to the housing half ( 12 ).