Method for Adjusting the Amount of Air in a Closed Air Supply System for a Chassis

• US 20070228676A1
• Filed: 04/25/2005
• Published: 10/04/2007
• Est. Priority Date: 05/19/2004
• Status: Active Grant

• Current Assignee: Continental AG
• Original Assignee: Continental AG
• Inventors: Stegmann, Axel
• Granted Patent: US 7,624,994 B2
• Time in Patent Office: Days
• US Class Current: 280/5.514
• CPC Class Codes: B60G 17/052 Pneumatic spring characteristics B60G17/048 takes precedence ; valves per se F16K
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/51222 Pneumatic
• CPC Class Codes: B60G 2500/2014 Closed systems
• CPC Class Codes: B60G 2500/30 Height or ground clearance
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption

Abstract

The object of the invention is to avoid pressure and volume compensation as much as possible during measurement of the pressures of the air spring units. According to the invention, the pressure in the air spring units (5, 6, 7, 8) is estimated prior to measurement of the pressures of the air spring units (5, 6, 7, 8) and is compared to the pressure in the air pressure accumulator (3). The higher of the two pressures determines the position of a 3/2 directional control valve (11) which separates the collector line (25) connecting all air spring units (5, 6, 7, 8) from the air pressure accumulator (3) or which connects it to as small a chamber volume of the supply system as possible.

Claims

1-5. -5. (canceled)

6. 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 collector line connecting all the air spring units with one another, an air pressure accumulator, which is connectable to the collector line, 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),

separating the collector line (25) from the air pressure accumulator (3) and all equal pressure chamber volumes in the event of a higher pressure in the air pressure accumulator (3),

connecting the collector line (25) to a smallest possible chamber volume in the event of a higher estimated pressure in the air spring units (5, 6, 7, 8).

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.

7. The method as claimed in claim 6, wherein the known parameters for estimating the pressure in the air spring units (5, 6, 7, 8) comprise at least one member of the group consisting of vehicle height, current loading and loading characteristics of the vehicle.

8. The method as claimed in claim 7, wherein the pressure in the air spring units (5, 6) of one vehicle axle is estimated and measured and then the pressure in the air spring units (7, 8) of another vehicle axle is estimated and measured, the measured pressure in the air spring units (5, 6) of the one axle being included for the estimation of the pressure in the air spring units (7, 8) of the other axle.

9. The method as claimed in claim 8, wherein chamber volumes at equal pressure to the air pressure accumulator (3) are formed by a compressor (2) and a dryer (15) and the smallest possible chamber volume is formed by the dryer (15).

10. The method as claimed in claim 8, wherein the collector line (25) is shut off from the air pressure accumulator (3) and the collector line (25) is connected to the smallest possible chamber volume of the air supply system by a 3/2-way valve (11) which is situated in a supply unit (1).