Part failure diagnosis for internal combustion engine using noise and vibration analysis

Former practice proves that the vibration and noise caused by rotating or alternately moving parts together with the physical and chemical processes inside an internal combustion engine contain a great amount of information about what happens inside the machine. The art of extracting useful information from time based vibro-acoustic signals is especially difficult in the case of an operating internal combustion engine because there are many vibration and noise sources and the rotation speed is not constant. The other problem is that the rotational speed is not constant in the case of an internal combustion engine during a single working cycle and in the course of continuous operation. we developed a method to follow the fine details of angular speed fluctuations e. g. because of the activity of single piston. Our purpose was to develop a flexible and improvable measurement system which is usable both for experiments and final tests of several engines. Using the measuring set-up we could exploit the order anal ysis function together with the analysis of results in the frequency domain