An internal combustion engine is considered as a material body, which characterized by inertial, elastic and dissipation properties, which are impacted from various forces. Oscillatory motion of a material body occurs in accordance with spectral characteristics of force and frequency responses of the system. The outer surface of the engine generates acoustic energy and causes mechanical noises.
The paper dwells on determining acoustic energy in accordance with the acoustical radiation rate if the radiation coefficient of the object observed is known. Also, the sound of the engine is presented as a sum of its separate acoustic powers, and there is determined the acoustic radiation coefficient of the engine for the entire surface, by using the acoustic radiation coefficient of each surface. Simultaneously, there is determined the vibro-energy distribution in the engine design, the assessment of which is made by means of the energy-transfer coefficient, which generates the frequency responses of vibro-acoustic parameters.