Machine vibration analysis for determining optimum operational engine speed

Abstract

The objective of the research was to analyse the amount of machine vibration and to approximate an optimum operational engine speed. The research was conducted on March 2009 until July 2009 in a dry field laboratory, Department of Biosystem and Mechanical Engineering, IPB, Bogor, West Java, Indonesia. Four operational engine speeds were applied to the five horsepower gasoline engine walking type cultivator and the amount of vibration on operator's hand was measured. When cultivator is operated on engine speeds of 1000 rpm, 1250 rpm, 1500 rpm, and 2000 rpm showed in variation of vibration on operator's hand. The vibration increases from 1000 rpm to 1250 rpm and then it decreases when the engine speed is increased after 1250 rpm up to 2000 rpm. The curve of the engine speed and the vibration relationship shows a polynomial equation. The equation is Y = - 8.464 + 0.03196 X - 0.000012 X', where Y is vibration (m/s') and X is engine speed (rpm). Based on the equation, it can be calculated that the highest vibration (12.816 m/s') is on 1330 rpm. Engine power is multiplication of torque and engine speed. Generally, a machine is operated on maximum torque for the best performance. When it is on that maximum torque, the machine vibration will be in maximum too. Based on the equation and the calculation, it can be approximated that optimum operational engine speed for soil cultivating is 1330 rpm. On that engine speed range, theoretically engine torque is in maximum range too. So, it can be recommended that the machine (i.e. the walking type cultivator) must be operated on engine speed range of 1330 rpm.