The Problem

Suspension systems provide a dual purpose which is contributing to the car’s handling and braking, and keeping vehicle occupants comfortable and reasonably well isolated from road noise, bumps, and vibrations. The current vehicles are using a passive suspension system that incorporates with hydraulic damper and mechanical spring. The conventional system is not assuring can improve the vehicle handling and passenger safety especially when the transportation research board had reported that 51 % of the serious car accidents are caused by rollover. The perfect automotive suspension system can absorb road shocks rapidly and could return to its normal position slowly while maintaining optimal tire to road contact.

However, this is difficult to realize by passive suspension system, where a soft spring allows for too much movement and a hard spring causes passenger discomfort due to road irregularities. Hence, the new approach is increasingly developed to influence the dynamic performance of the vehicle. A new method and product has been introducing to the automotive industry to overcome this problem. Basically in order to model and investigate the dynamic behavior of the suspension system, a full car model is preferred (Kruczek & Stribrsky, 2004).

However roll and pitch behavior can also be modeled as an equivalent force disturbance acting on the body mass. Hence, this paper is concentrated on a quarter car model. Conventionally the passive suspension is installed on the current vehicle. The quarter car model for this passive suspension system that consists of one-fourth of the body mass, suspension components and one wheel are represented. Meanwhile, the quarter car model for semi-active suspension system where the magneto-rheological (MR) fluid as a damper fluid is installed in parallel with the mechanical spring.

The assumptions of a quarter car modeling are as follows: the tyre is modeled as a linear spring without damping, there is no rotational motion in car body, the behavior of spring and damper are linear, the tyre is always in contact with the road surface, and effect of friction is neglected so that the residual structural damping is not considered into vehicle modeling. The concept of this suspension is basically replaced the damper to the MR fluid. The main component that greatly determines the performances of MR dampers is the valve that is usually located inside the piston. When the MR fluid is exposed to magnetic field, he iron particle will be formed into chain-like structure which increase the shear stress of the fluid in less than 10ms. And thus, it will create the damping zone; so that it can be react as a conventional suspension.

The solution

UTM-CIAM helped PROTON to develop and implement a car suspension system with a MR fluid damper (MR damper).

Team members: John Ockendon, Wan Ahmad Tajuddin bin Wan Abdullah, K.K.Viswanathan, Shamsuddin Ahmad, Normah Maan, Yusof Yaacob, Akbar Banitalebi, Saira Javed, Karthik Krishnan, Mohammad Amirul Affiz Afripin, NurulIzyan Mat Daud, Siti Nur Haseela Izani, Marhaini Mohamad Ibrahim, Azisyahirah Azizan, Nor Hafizah Ahmad Kailani.