Regressive models for condition diagnosing marine diesel engine by torsional vibrations on propulsion shaft-line

Abstract

This paper presents results of study in building diagnostic regressive models (RMs) of cylinders in Marine Diesel Engine (MDE) using torsional vibration signal (TVS) on the propulsion shaft-line. For diagnostic purpose, the vectors of diagnostic signs (VDS) were designed and constructed based on the features of the TVS: maxima and minima relatively with [Formula: see text] working cylinders in real-time domain, or amplitudes of [Formula: see text] first harmonics ([Formula: see text] for two-stroke MDE, and [Formula: see text] for four-stroke MDE) in frequency domain. The received RMs are equations showing the relationships between the diagnostic sign [Formula: see text], [Formula: see text] ([Formula: see text] or [Formula: see text]) of the TVS and [Formula: see text] factors [Formula: see text], [Formula: see text] which specify common states of [Formula: see text] DME’s cylinders. The factor [Formula: see text] here was calculated by using firing coefficient Cfi ([Formula: see text] = 2Cfi-1; Cfi = 0 when [Formula: see text]-cylinder is misfired, and Cfi = 1 when [Formula: see text]-cylinder is normally fired) value of each cylinder. The Fractional Factorial Design of experiments (DoE) [Formula: see text] was used to build the mentioned RMs. The MDE on MV.HR.34000 DWT, with [Formula: see text] and [Formula: see text] was observed and analyzed. The calculated linear regressive models were tested based on the [Formula: see text]-distribution standard.