Patent ID: 7637517

Claim:
A vehicle height adjustment system capable of adjusting a vehicle height of a vehicle by supplying air from an air suspension air tank to an air spring or discharging air from the air spring, comprising: a compressor operable to produce compressed air; an air supply/discharge control valve operable to control air supply and discharge to/from the air spring, the air supply/discharge control valve being provided between the air suspension air tank and the air spring; control means for controlling valve opening and closing operations for supplying and discharging air of the air supply/discharge control valve; an air passage connecting the compressor and the air supply/discharge control valve, bypassing the air suspension air tank; a protection valve opened and closed according to internal pressure of the air passage, the air suspension air tank connected to the air passage via the protection valve, and internal pressure value detection means for detecting a value of an internal pressure in the air passage, wherein the protection valve is opened only when the internal pressure value of the air passage becomes equal to or higher than a predetermined value, the control means controls start and stop of air supply control of the air supply/discharge control valve, based on the internal pressure value detected by the internal pressure value detection means, the control means staff air supply control of the air supply/discharge control valve when the internal pressure value detected by the internal pressure value detection means becomes equal to or higher than a predetermined internal pressure value, the predetermined internal pressure value is lower than the predetermined value, and the control means allows height adjustment to staff without first charging the air suspension air tank.