The influence of vehicle tyres pressure on the suspension system response by applying the time-frequency approach

Maintaining correct inflation pressure in tires helps to keep vehicle handling, passenger comfort and braking at its best, as well as improving fuel efficiency and tire life. Therefore it is very important that the tires are correctly inflated. To address this problem, in the present study experimental investigations have been carried out to identify the effect of under-inflated tires on suspension system performance by measuring vertical acceleration (vibration) of the suspension system. The experimental work has been conducted by driving a car on the road with range of inflation pressure at four conditions (e.g. at standard pressure (2.3bar) and at 1.5bar of passenger wheel, driver wheel and front wheels). During the experiment the signals of tire pressure, the suspension vibration and the car speed were measured. To analyze the signals, the Short-Time Fourier Transform (STFT) method was used to detect the effects of tire inflation on the performance of suspension. The STFT technique has provided time-frequency information and the frequency components of the signal with relative maximum energy transmitted to the car body. The results show that, when the tires were under-inflated by approximately 35 percent, it was significantly increased the vibration of the car body by up to 30 percent. The analysis has also shown that STFT analysis is more accurate than the spectrum analysis for distinguishing of the tire fault. These effective measurements potentially will use to develop an online condition monitoring system in future.