Patent ID: 7624994

Claim:
A method for adjusting the amount of air in a closed air supply system for a chassis with a plurality of air spring units, a compressor ( 2 ) with a suction side and a pressure side, a collector line connecting all the air spring units with one another, an air pressure accumulator, the suction side being connected to a first suction line ( 10 ) and a second suction line ( 18 ), each intake line ( 10 , 18 ) having a nonreturn valve ( 13 , 19 ) opening in the direction toward the suction side, a second supply line ( 20 ) connecting the pressure side to the collector line ( 25 ) via a first 3/2 way valve ( 11 ), a first supply line ( 14 ) connecting the pressure side to the air pressure accumulator ( 3 ) via a second 3/2 way valve ( 17 ), the first 3/2 way valve ( 11 ) connecting the collector line ( 25 ) with either the second supply line ( 20 ) or with the first suction line ( 10 ), the second 3/2 way valve ( 17 ) connecting the air pressure accumulator ( 3 ) either with the first supply line ( 14 ) or with the second suction line ( 18 ), the method comprising the steps of estimating the pressure in the air spring units ( 5 , 6 , 7 , 8 ) on the basis of known parameters comparing the estimated pressure in the air spring units with a known pressure of the air pressure accumulator ( 3 ), connecting the collector line ( 25 ) to the first suction line ( 10 ) in the event the pressure in the air pressure accumulator ( 3 ) is higher than the estimated pressure in the air spring units ( 5 , 6 , 7 , 8 ), connecting the collector line ( 25 ) to the second supply line and connecting the air pressure accumulator ( 3 ) to the second suction line in the event that the estimated pressure in the air spring units ( 5 , 6 , 7 , 8 ) is higher than the pressure in the air pressure accumulator ( 3 ), measuring the pressure in the collector line ( 25 ), calculating therefrom an actual compressed-air amount of the air supply system with the inclusion of further known parameters, comparing the actual compressed-air amount with a target compressed-air amount to obtain a differential compressed-air amount, and equalizing the differential compressed-air amount accordingly.