VERTICAL DYNAMICS OF THREE WHEELED MOTOR VEHICLES

Abstract

In an effort to respond to the impact of the ever-increasing fuel costs, the automobile industry has been developing smaller and lighter passenger vehicles. In India, the three-wheeled passenger vehicle has emerged as a popular and successful alternative to the passenger cars and vans. However, the three-wheeled vehicle has not evoked the interest of researchers worldwide, albeit a few who investigated the stability and handling characteristics of three- wheeled motor vehicles and compared it with those of four wheeled vehicles. Therefore, the present study has been undertaken with an aim to analyze and improve the ride performance of three-wheeled vehicles. The vehicle ride behaviour is concerned with the vibrations of the vehicle body, which are a function of the mass and moment of inertia parameters of the vehicle body, suspension properties, tyre ride characteristics, aerodynamic forces and road surface irregularities. Tyre ride properties such as static and rolling dynamic stiffness and damping properties for small size pneumatic tyres used in three wheeled vehicles, have been experimentally determined in the laboratory. The effect of various parameters such as tyre size, inflation pressure, normal load and speed on these ride properties was studied. Using linear regression analysis, the rolling dynamic stiffness and damping coefficients for four different tyres were presented in the form of equations, which are convenient to use.