Performance Design of Hydraulic Mount for Low Frequency Engine Vibration and Noise Control

The use of the hydro-elastic mount for passenger car engine as well as for heavy vehicle diesel engine is increasingly becoming common in the industry because they can provide excellent frequency and amplitude response characteristics compared to the conventional elasto-rubber type engine mount. Numerous articles have been attempted up to now to explain the complex performance charateristics of those mount but is not fully understood yet. In the present study a hydro engine mount with a circular inertia track and a free decoupler is designed for a 110 PS class In-line diesel engine in order to control and reduce the high amplitude low frequency vibration and noise in frequency range of 1 - 50 Hz in particular. A linear lumped model is developed in the study to analyse the dynamic response characteristics and the dynamic spectra results from the model are validated with experimental data over 1 - 50 Hz. Special emphas is has been placed on the design parameter studies, such as or if ice diameters and length of inert ia track, to tune the mount performance for the specific mount design requirements as well as to predict the performance characteristics in the pre-design stage. Applying these results to the mount design process a methodology to improve or tune the required basic performance of the mount is obtained.