Retrofitted rear suspension efficiency

Abstract

It is popular to retrofit cargo van to passenger mini Bus. Such retrofitting is based on cargo vans, gross weight up to 5t and intended for 10 - 22 passenger seats. Usually the retrofitters in order to improve vehicle ride and passenger comfort are upgrading suspensions. The main aim of this investigation is to compare ride differences of the retrofitted rear vehicle suspension and to evaluate vehicle dynamic characteristic improvement. Three types of a quarter vehicle rear suspensions dynamic models are presented. The first one is a typical cargo van leaf spring suspension, the second most popular retrofitted suspension with additionally mounted air chamber; the third one has modified leaf spring at one end fixed to the vehicle body through an air chamber. As the road disturbance is used speed reduction bump. Mathematical simulation is made with Maple using Runge-Kutta method. Paper presents variation of the different suspensions natural frequencies; quarter vehicle body accelerations and air spring pressure dependences on natural frequencies of quarter vehicle rear suspension; quarter vehicle vertical body accelerations in respect to time. Dynamic characteristics of all three vehicles rear suspensions are compared and the results are listed.