Patent ID: 6726189
Filing Date: 2004-04-27
Classification: B60G

Abstract:
A closed level control system for a vehicle having a vehicle body, vehicle axles and pressurized medium chambers with which the vehicle body is suspended relative to corresponding ones of said vehicle axles, the closed level control system comprising:a single unsubdivided pressurized medium supply vessel for holding a medium under pressure as a pressurized medium; a compressor for transferring said pressurized medium between said supply vessel and said pressurized medium chambers; said compressor having an input and an output; a first controllable directional valve switchable between a base position wherein no throughflow is permitted and a switched position wherein throughflow is permitted; a first pressurized air line connecting said supply vessel to said input of said compressor via said first controllable directional valve; a second controllable directional valve switchable between a base position wherein no throughflow is permitted and a switched position wherein throughflow is permitted; a second pressurized air line connecting said output of said compressor to said pressurized medium chambers via said second controllable directional valve; said pressurized, medium being transmitted from said supply vessel to said pressurized medium chambers by said compressor when said first and second controllable directional valves are in said switched position; a third controllable directional valve switchable between a base position wherein no throughflow is permitted and a switched position wherein throughflow is permitted; a third pressurized air line connecting said input of said compressor to said pressurized medium chambers via said third controllable directional valve; a fourth controllable directional valve switchable between a base position wherein no throughflow is permitted and a switched position wherein throughflow is permitted; a fourth pressurized air line connecting said output of said compressor to said pressurized medium supply vessel via said fourth controllable directional valve; said pressurized medium being transmitted from each of said pressurized medium chambers to said supply vessel by said compressor when said third and fourth controllable directional valves are in said switched position; said pressurized medium being transmitted from said supply vessel to said pressurized medium chambers by said compressor when said first and second controllable directional valves are in said switched position; an air dryer mounted in said fourth pressurized air line; an intake valve switchable between a base position wherein no throughflow is permitted and a switched position wherein throughflow is permitted; an intake line ending at said intake valve and connecting said input of said compressor to the atmosphere when said intake valve is in said switched position; a discharge valve switchable between a base position wherein no throughflow is permitted and a switched position wherein throughflow is permitted; a discharge line branching off from said fourth pressurized air line at a branch point between said output of said compressor and said air dryer and ending at said discharge valve; and, said supply vessel being connectable to the atmosphere via said air dryer and said discharge line when said discharge valve is in said switched position.