Evaluation of the effectiveness of the air suspension of the bus

When designing vehicles intended for passenger transportation, considerable attention is paid to increasing comfort, in particular, reducing vibration loading of interior elements. The article provides an overview of various approaches to solving this problem: using active suspension systems, applying pneumatic-hydraulic springs, shock absorbers with variable characteristics, pneumatic suspension systems. The article examines the suspension system of a bus based on the Ural all-wheel drive vehicle. A distinctive feature of this vehicle's suspension is the use of ROSTAR air springs. The longitudinal guide levers are located opposite each other. The proposed air suspension scheme allowed the use of wide-profile tires of larger sizes in the vehicle's chassis without increasing the dimensions. In order to check the efficiency of the suspension system under consideration, running tests were conducted. The bus moved along a dirt road of category 4-5, with potholes, at a speed of 20 km/h. Accelerometer sensors were installed on the body and elements of the chassis. The article provides information on their location and signal processing features, as well as other test conditions. Based on the results of the preliminary tests, the frequency range for the studies was selected. As a result of further tests, the root-mean-square values of vibration accelerations in standard octave and one-third octave bands were obtained for the signals of all sensors. The analysis of the effectiveness of the suspension system was performed based on a comparison of vibration accelerations on unsprung masses with vibration accelerations in the passenger compartment and at the driver's workplace. The test results confirmed the high effectiveness of the proposed suspension system. The frequency ranges in which increased vibration accelerations are recorded were determined. Measures for their reduction were proposed. The developed design scheme was recognized as effective and recommended for use in suspension systems of buses.