Vibration isolation of a four cylinder internal combustion engine

People had dreamt flying since first ages. They cannot realize that dream until recently. Flying passion, which had started with Wright Brothers, has reached very advanced level today. Intercontinental distances become to wend shorter time. Invention of airplane marked an era at transport sector. The internal combustion engine, which the most important invention of our era, make longer distances at a shorter time possible. It gave a big circulation freedom to people. Invention of steam machine made a step forward for industry and it allowed being born vacation concept. The invention of internal combustion engine made a major step forward for industry in contrast to innovations of steam machine. Rudolf Diesel's invention of compression ignition internal combustion engine opens new areas which hadn't used engine as major powertrain for internal combustion engines. The steam machine which had been used by indutrial enterprises replaced with compression ignition engine. Compression ignition engine which is the most efficient internal combustion engine had been developped for years, so they made the major powertrain of trains, military vehicles, ships, agricultural vehicles, etc. Agricultural vehicles had changed their powertrain to diesel engine, and this situation made an agricultural revolution in a sense. Diesel engine is used by lots of different areas, using diesel engine in aviation sector is very limited in comparison to other sectors. In railway and motorway transportation, the diesel engine has the largest usage rate; however, in the airway transportation the diesel engine has not the same situation. The diesel engine has not fulfilled. The lightness condition of avation sector for long years. Until Second World War, the internal combustion engine spesicifically diesel engine was used to use widely in aviation, but after the new developments and advances of jet engines, the internal combustion engines replaced with jet engines in aviation. Nowadays, that situation has begun to change. Advancements at the technology enable to build lighter, more efficient and more powerfull diesel engines. Thus, small and sportive planes can use diesel engines. However, diesel engines has not dominated the aviation market. Improving technology will help the diesel engine to dominate. Nowadays, lots of airplane manufacturer has started to use internal combustion engines for their planes. Especially diesel engine's popularity is increasing in aviation industry slightly. Interest of aviation is getting more and more. So, the diesel engine has a chance to dominate small plane market. The better fuel efficiency of the diesel engines will be made first choise of the people who has interest on aviation and plane manufacturers. In this thesis, usage of the diesel engine which is the most important invention of the world and marked an era at aviation will be examined. Diesel engines which are used in marine and land applications operate with more vibratory in contrast to their cousins gasoline engines. For this reason, vibration caused by engine can cause discomfort and xxii even damage to vehicle. The vibrations caused by engine should be avoid to transfer to vehicle. The biggest source of engine vibration is inertia moments from moving parts inside the engine and combustion. Lots of solution are developped for this case. The most common solution is using balance shafts for cancelling this vibrotary forces. Another solution is adding counterweights to crankshaft. This solution be used almost every engine. The lightness is one of the most important concern in aviation applications. Because of that situation adding mass to engine isn't a solution. In this thesis, the vibrations will be tried to avoid to transfer to vehicle with identification of right engine mount parameters. Engine mounts may be the most important parts of the engine. Engine mounts provide to not transfer vibrations which caused by engine to vehicle and not transfer to vibrations which caused by vehicle to the engine. Also, engine mounts carry the weight of the engine. So, identification of the right parameters of the engine mounts is very important. Because, identification of the wrong parameters may cause resonances at operating, lie at nonnominal position, and discomfort. In this thesis, catastrophic consequences of the vibration are tried to avoid. To provide this, parameters of the engine mounts will be optimized. The method which is used to decrease vibrations is the maximum natural frequency of the engine keep smaller than specific value. To provide this, the parameters of the engine mounts were optimized. So, the proper values were reached. The engine mount optimization in this thesis is explained briefly, the equations of motion of the engine were calculated firstly. The engine was modelled as rigid body has six degree of freedom. Lagrange method was used for calculating equations of motion. Lagrange method make calculating equations of motions of systems has high degree of freedom easier. For the solution of that type problems, there are several methods. In this thesis, analytical solution method was preferred. The equations of motions which were calculated were converted to an eigenvalue problem and solved. Thus, six number calculated second order differential equations were convert to twelve number first order differential equations via replacing parameters. Eigenvalues of the equations were calculated. The equations of motion were solved via calculated complex eigenvalues. For verifying the rightness of the equations which were calculated, equations were solved via numerical method with same initial conditions. After that, two solutions were compared with each othercand were observed. The analytical and numerical solutions were identical. The eigenvalues which were calculated from the engine's equations of motion were optimized via changing stiffness and damping coefficients. The eigenvalues were tried to keep under a boundary. So, effect of excitation forces were caused by operation of engine decreased. For optimizaton, target and penalty functions were identified. In optimization process, different scenarios were identified so stiffness and damping coefficients of the engine mounts were calculated with these scenarios. In identification of scenarios phase, target and penalty functions were changed. Also the equalities of engine mounts were evaluated. The results which were calculated were compared with each other. After that, the most suitable solution of optimization was choose. The calculated unbalance forces of the engine were applied to the choosen optimization result. The behaviour of the system was examined. After examination, the behaviour of the system was observed at desired level. The amplitudes of the system were observed at reasonable level when the engine operating. So, the calculated stiffness and damping coefficients from optimization are observed as the optimum values for that engine. Finally, a sensivity analysis was done for the equations of motion. Thus, which parameters has impact on the results was observed. The first prototypes will be constructing with optimized engine mount parameters. After that, the validation tests will be run on engine. So, the engine mount parameters will be validated. The possible corrections for the engine mounts may be considered according to test results. Finally, the engine mounts will be transformed from prototype to product.