Vibration measurement based analyses of internal combustion engines

Nowadays automotive manufacturers face a two-fold challenge; on the one hand they have to fulfil the costumer satisfactions; on the other they must decrease the production costs by meeting the many regulations. Due to the depletion of fossil based fuel, alternative fuels have gained great importance in automotive sector in last decades. Therefore all effects of them must be well-known on internal combustion engine. In this thesis, noise and vibration characteristics of diesel engines fuelled with different alternative fuels have been studied in details. Throughout the experimental study, three different test rigs were used. At the first rig, the diesel engine was fuelled with low sulphur diesel fuel, sunflower biodiesel, canola biodiesel, and corn biodiesel blends. Engine vibration has been recorded at different engine speeds in order to validation of experiments on other experimental engines. At the second test rig, the diesel engine was additionally fuelled with hydrogen and natural gas additions through the intake air. At this test rig, noise, vibration and emission characteristics were evaluated at various engine speeds. At the last test rig, the same biodiesel blends were used in order to examine their engine combustion characteristic. The results revealed that biodiesel, hydrogen and natural gas additions lowered the engine block vibration, noise and most of exhaust emissions that of low sulphur diesel fuel.