Effect of Distributions of Static Suspension Deflection on Ride Comfort of High-Speed Passenger Cars

In order to improve the ride comfort of high-speed passenger cars, a study was made on the static deflection of suspension system, and the relationship between the total static deflection and the static deflection ratio of the secondary to primary suspension was discussed. According to the vibration theory and the principle of multi-body system dynamics, the forced oscillation characteristics of 2-DOF wheel load system were studied for different static deflection ratios, and a high-speed vehicle model was established to investigate the influence of static deflection distributions on ride quality at various speeds. The results show that as the deflection ratio of the wheel load system increases, the carbody acceleration reduces when the vertical vibration frequency of the carbody is within 4 Hz, but it is comparatively small for deflection ratios of 1.0 and 2.0 when the vibration frequency is above 4 Hz. By increasing the deflection ratio, bogie vibrates more violently, the carbody lateral stability worsens slightly, and the vertical vibration accelerations within the frequency range from 2 to 10 Hz become larger significantly. The vertical ride comfort index values of static deflection ratios 0.5 and 8.0 are 1.5% and 6.0% higher than that of static deflection ratio 2.0.