The Crankshaft of Internal Combustion Engines as a Source of Vibrations - Experimental Methods and Results
Published October 17, 1994 by Society of Automotive Engineers of China in China
In former investigations concerning engine vibrations the uneven mass distribution of crankshafts due to the location of counterweights was found to cause crankshaft bending. The well accepted balancing method of crankshafts, where holes are drilled into the counterweights, increases this problem due to occasionally asymmetric location of those drillings. This effect may bring about specific problems such as additional load on the engine block, a increasing noise level and even unwelcome movements of the flywheel. The objective of the described examinations was to investigate the behavior of a newly developed, fast running, 4-cylinder in-line SI engine with a light-alloy cylinder block under variation of the inner mass compensation of the crankshaft. An evident relationship was found between the extent of inner crankshaft imbalance and engine block bending occurring in the 1st order of engine speed. With a non-contact distance measuring device longitudinal and tumble flywheel movements in the 1st and 2nd order of engine speed were observed.