THE SPRING AND PNEUMATIC SUSPENSION VEHICLE OPEL VIVARO ELEMENTS STIFFNESS COEFFICIENT RESEARCH

Abstract

The study investigates the stiffness characteristics of the spring and pneumatic suspension elements of an N1 category vehicle - Opel Vivaro. The relevance of the topic is driven by the need to improve the ride comfort of the vehicle, which directly affects the comfort and safety of both the driver and passengers. Particular attention is paid to the comparison between a traditional coil spring and a rolling-lobe type pneumatic element, as alternative suspension components in the modernization of the rear suspension of the Opel Vivaro. An analysis of existing regulations regarding human exposure to vibration (DSTU, ISO, EN, etc.) is conducted, along with consideration of physiological criteria for assessing vehicle ride comfort. It has been established that optimal suspension stiffness should minimize vertical body accelerations in accordance with permissible vibration exposure thresholds. The methodology of the study is based on loading the elastic element using external forces, which are applied during testing via a hydraulic jack equipped with a built-in pressure gauge. In this context, stiffness is examined as a function of pressure, height, and the effective area of the working elements. All input parameters were obtained experimentally. It was determined that for both the metallic and pneumatic elastic elements, the relationship between the restoring force and deformation within the working range can be described by a parabolic law. The obtained data were approximated using quadratic regression with high accuracy, as indicated by the R² coefficient. As a result of the comparative analysis, it was found that the pneumatic element exhibits variable stiffness, allowing the suspension to better adapt to driving conditions. This improves ride comfort, reduces accelerations transmitted to the vehicle body, and enables ride height adjustment based on load. The metallic element has a simpler design but provides a lower level of comfort, particularly under variable loads and as the metal ages. The obtained results can be used in the modernization of existing vehicles, as well as in the development of new suspension designs incorporating adaptive pneumatic systems. The use of pneumatic elements is especially advisable for vehicles where comfort, stability, and flexibility in chassis tuning are of primary importance.