Abstract
Comfortable ride is one of the main index of comfortable vehicle and engine mount plays important role in it. Automobile industries are in need of reducing the vibration forces to satisfy customer requirements. Vibration of car engine arises from unbalanced forces of engine, which are transmitted from engine to chassis, and road-induced vibration which is controlled by using proper engine mounts and suspension system. The purpose of this thesis is to study the vibration of automobile engine. Engine mount with elastomeric and hydraulic mounts are developed. Their performance evaluated using bond graph on entire frequency range. Engine mount parameters are optimized by using bond graph optimization method. Sources of engine excitation forces are identified. Engine reciprocating and rotating parts contribute in generating vertical excitation forces. Mounts characteristics are analyzed by their excitation frequency and amplitude. Hydraulic engine mount are more effective than rubber mount because their frequency and amplitude response is superior. Fluid analysis is more complex so linear models and theory on two degree of freedom is developed in this thesis. Presently companies are more concern about customer satisfaction in automobile industries. Passenger may get more comfort if vibration induced due to uneven road or engine is reduced. Selection of proper engine mount, location and optimization of mounts’ parameter as per application is required. Force transmitted to passengers needs to be reduced. In this thesis, I applied knowledge from my curricular courses like vibration technology and computer aided design of dynamic system, which helped me to build bond and block diagram of whole powertrain system. I used software CAMPG, Matlab, Mathematica and Nastran to optimize parameter. Hydraulic engine mounts can be made more effective by varying the inertia area and stiffness parameter. They can operate on wide frequency range by varying stiffness using inertia area. Transmissibility is reduced which enables more comfortable ride.