A Study on Separation of Combustion Noise Using a Transient Noise Generation Model

It is necessary to elucidate the noise generating mechanism for reducing engine noise. In a running engine, various impacts in the engine cause excitation sources for structural vibrations and engine noises. Engine noises are classified into the combustion noise, the combustion induced mechanical noise, and the mechanical noise depending on their excitation source. However, it is difficult to measure such noises separately because some impacts generate closely together in time and space. In order to separate the combustion noise from the total engine noise, a transient noise generation model that considers the vibration transmission and the damping effect of the engine structure was proposed. The newly proposed model was verified by conducting the single explosion excitation experiment of a stationary engine. In addition, it was clarified that the time histories of the combustion noise of both gasoline and diesel engines could be estimated at firing condition.