Abstract: Suspension leveling of electronically controlled air suspension is a complicated nonlinear procedure. To research the dgnamic of suspension in leveling procedure with air spring inflated or deflated, and to serve as a basis for the follow-up research on suspension height control strategies, analyses are performed on the gas thermodynamic process in air spring and spring loaded mass dynamic process in leveling procedure of electronically controlled air suspension, from which the equations of air spring pressure gradient, gas loop flow rate, and spring loaded mass dynamics in the open period of and after closing of magnetic valve in leveling procedure are derived. A series of suspension leveling experiments in full scale vehicle with different single pulse exerted magnetic valve to inflate or deflate air spring are conducted to verify the proposed nonlinear model, the results of experiments and simulations show good consistency. The proposed model can correctly depict the gas state in air spring before and after loaded magnetic valve, and the lag characteristic of suspension motion under the action of damping force after the closing of magnetic valve.

Key words: Electronically controlled air suspension, Leveling, Magnetic valve, Nonlinear model