Measurement and analysis of angular velocity variations of twelve-cylinder diesel engine crankshaft

This paper presents the procedures for measuring and analyzing the angular velocity variation of twelve-cylinder diesel engine crankshaft on its free end and on the power-output end. In addition, the paper deals with important aspects of the measurement of crankshaft torsional oscillations. The method is based on digital encoders placed at two distances, and one of them is a sensor not inserted directly on the shaft, i.e. a non-contact method with a toothed disc is used. The principle based on toothed disc is also used to measure the actual camshaft angular velocity of in-line compact high-pressure pump the engine is equipped with, and this paper aims to demonstrate the possibility of measuring the actual angular velocity of any rotating shaft in the engine, on which it is physically possible to mount a toothed disc. The method was created completely independently during long-range development and research tests of V46 family engines. This method is specific for its particular adaptability for use on larger engines with extensive vibrations and torsional oscillations. The main purpose of this paper is a practical contribution to all the more interesting research of the use of engine crankshaft angular velocity as a diagnostic tool for identifying the engine irregular running.

► This paper presents measuring and analyzing the angular velocities variations of crankshaft.
► This method is specific for its particular adaptability for use on larger engines.
► The paper deals with important aspects of the measurement of crankshaft torsional oscillations.
► This was enabled by the use of two different sensors at the end of the crankshaft.
► Procedure of the processing of raw signals from these sensors is described.