Patent ID: 6685174
Filing Date: 2004-02-03
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 pressurized medium supply vessel for holding a medium under pressure as a pressurized medium; a pump for transferring said pressurized medium between said supply vessel and said pressurized medium chambers; said pump having an input and an output and said pump being configured so as to permit said pump to pump said pressurized medium from said input to said output thereof; a first controllable directional valve; a second controllable directional valve; a first pressurized medium line connected to said supply vessel and being connected via said first controllable directional valve to said input of said pump; a second pressurized medium line connected to said pressurized medium chambers and being connected via said second controllable directional valve to said output of said pump at least when said pressurized medium is to be transferred from said supply vessel into said pressurized medium chambers; a third pressurized medium line connected to said pressurized medium chambers and being connected via said first controllable directional valve to said input of said pump; a fourth pressurized medium line connected to said supply vessel and being connected via said second controllable directional valve to said output of said pump at least when pressurized medium is to be transferred by said pump from said pressurized medium chambers into said supply vessel; a single pressure sensor mounted in said third pressurized medium line; said single pressure sensor being connectable to said first and fourth pressurized medium lines via said first and second controllable directional valves; and, ancillary valve means switchable between a first position wherein said single pressure sensor is connected to at least one of said pressurized medium chambers for measuring the pressure therein and a second position wherein said single pressure sensor is connected to said pressurized medium supply vessel for measuring the pressure therein.