International Conference on Science & Technology: Applications in Industry& Education (2008) EXPERIMENTAL HEAT TRANSFER STUDY ON THE SHOCK ABSORBER OPERATION Mohd Shahrir Mohd. Sani, Erlifi Husin & Muhamad Mat Nor Faculty of Mechanical Engineering Universiti Malaysia Pahang (UMP) Tun Abdul Razak Highway 26300 Gambang Kuantan Pahang e-mail: mshahrir@ump.edu.my, erlifi@ump.edu.my and Hmuhamad@ump.edu.my phone: +609-5492209/+6013-3426076 0BAbstract. This paper focused on the experimental heat transfer study on the shock absorber operation. The objective of this study is to analysis the heat transfer rate at surface absorber body. The shock absorber test rig was developed to collect experimental data. This test rig also useful to test and indicates the condition of shock absorber. A new and modify shock absorber twin tube type 1600cc will be used for this experiment. Ethanol and water are using as alternative substance for damping fluid to improve the air gap between the internal and outside body. Ten cycles of bounce and jounce shock absorber operation before heat transfer were measured. The problem of overheating will be effect of damping fluid characteristics and decrease shock absorber performance. However, using additive on damping fluid with water or ethanol will be good substance to improve heat transfer inside the absorber. Ethanol as a substance can be increased heat transfer inside absorber up to 38%. Furthermore, water has a higher thermal conductivity and increasing heat transfer rate better than ethanol; the result shows that using the water can increased the rate of heat transfer up to 45%. Finally, additive with higher thermal conductivity as the substance should give better heat transfer rate from inside absorber to surroundings. Keywords: Heat Transfer, Shock Absorber, Damping Fluid, Water and Ethanol. Introduction An automotive suspension system is meant to provide safety and comfort for the occupants. Shock absorber is an important part of automotive suspension system which has an effect on ride characteristics such as ride comfort and driving safety. In every moving vehicle there must have a good suspension to absorb the shock of the tires and wheels meeting bumps and holes in the road. The suspension system looks unnecessary to us but it gives a great responsibility or doing an important job to give a safety ride. If there is no suspension install to the vehicle, it will cause a great shock when the tire meets bad condition of the road and give some damage to the component inside the vehicle. It also gives uncomfortable to the driver and passenger when the car is taking corner or breaking. One part of the suspension is the absorber. It is connected between the frame and suspension. Shock absorbers may increase the ride-height which could affect the stability of the car and thus the safety. However, the handling of some cars may even improve by using these shock absorbers. Thus the shock absorber can give results in the best road holding, safety and comfort. Shock absorbers are also critical for tire to road contact which to reduce the tendency of a tire to lift off the road [1]. This affects braking, steering, cornering and overall stability [2]. The removal of the shock absorber from suspension can cause the vehicle bounce up and down. It is possible for the vehicle to be driven, but if the suspension drops from the driving over a severe bump, the rear spring can fall out [3]. The goal of the shock absorber is to dampen spring oscillation by converting the kinetic energy from spring movement into heat energy [2]. In order to reduce spring oscillation, shock absorber absorbs energy. The shock absorber absorbs different amounts of energy depending on how fast the suspension is moving. If high heat inside the absorber occurs, it will heat the damping fluid. This will change the molecular structure and density of fluid inside the absorber that cause it's damping capability to be decrease. In other words, shock absorber also could be call as the energy converter. Heat transfer occurs when there has a temperature different in a medium or between media. When a temperature gradient exists in a stationary medium, which may be a solid or a fluid, the term conduction is use to refer to the heat transfer that will occur across the medium [4]. Shock absorbers absorb shock on the road and 759