Variable Spring Rate Adaptive Suspension System

A vehicle?s suspension is a system intervening the interface between the vehicle and the road. The basic function of the suspension system is to isolate the passengers and chassis from the excitation due to road unevenness to provide better ride comfort, road holding and stability. It is also seen that a good suspension should be soft for good ride comfort and be stiff to have insensitivity to applied load variations and should have a setting between soft and stiff suspension for good handling. The existing conventional passive suspension systems are unable to satisfy the conflicting criteria of a balance between the ride comfort and road handling. It was observed that, a good ride is obtained with relatively modest damping around 20% critical damping and to minimize suspension displacement and dynamic tyre force. These objectives are not fulfilled by a conventional passive suspension system because of its limited scope of variation in spring stiffness and damping coefficient. By identification of the scope to provide the better means to improve the conventional suspension principle, the theme of implementation of a variable-Hydraulic Suspension is proposed. The major objective of my paper is to vary the stiffness of the spring according to the driver?s decision. The stiffness of the spring can be changed by varying the travel in the suspension system. There are 3 modes in the driver's cockpit so that the driver can select any one of the three he wanted. The 3 modes are race mode, normal mode and luxury mode. In race mode, the travel of the spring is reduced so that the handling characteristic of the vehicle is increased. In luxury mode, the travel of the spring is increased so that the passenger?s comfort is increased. In normal mode the travel is moderate so that it balances both handling and comfort characteristic. Thus our system allows the driver to vary the characteristics of the system as required. Thus this system can replace the conventional passive system in passenger car in a cost effective way.