PARAMETRIC STUDY OF SUSPENSION SYSTEM FOR A LOW MASS VEHICLE

Abstract

Automobile Industry is currently focused in developing and discovering ways to improve fuel economy of the vehicles, keeping in view the rapid consumption of world‟s energy reserves. There may be several solutions to this problem, like altering the automobile engine to operate on some alternate fuel or altogether reshaping the automobile engine functionality which can generate comparable power output with less fuel consumption, but currently the most popular approach in the industry is to develop light weight vehicles, which seems to be a more appropriate solution to the said problem. Though light weight vehicles may seem to be an appropriate solution for improved fuel economy but there is a drastic change in the dynamic behavior of such vehicles. Vehicle Dynamics is usually gauged in terms of ride and handling of the vehicle. Suspension along with the tires defines the vehicle dynamics. Mass of the vehicle also plays a vital role in the vehicle dynamics, and reducing the mass may result in significant degradation of vehicle‟s dynamic performance. Suspension System performs the job of not only damping the vibrations coming from the road but also it supports vehicle‟s weight, keeps tires in contact with the road to maintain traction and also keeps the wheels in the desired orientation. Thus both ride and handling maybe controlled by controlling the Suspension System parameters. The Sprung Mass of a light vehicle varies significantly during operation. Therefore, in order to achieve appropriate dynamic performance from a light weight vehicle its suspension must be designed accordingly. This thesis presents a study on the effects of Suspension System on a Low Mass Vehicle by changing its parameters to achieve appropriate Ride Performance. Both Traditional and Bond Graph modeling techniques are used to model and analyze the vehicle system, and a comparison between the two techniques is also presented to decide which technique is more suitable for the modeling and analysis of vehicle dynamics. Simulations are carried out in MATLAB and 20-sim software for evaluating the ride performance and based on these simulation a frame work for designing a Low Mass Vehicle is defined.