An investigation of crankshaft oscillations for cylinder health diagnostics

Real-time brake torque estimation for internal combustion engines

“…The premise of the model is that engine brake torque causes repeatable crankshaft dynamics when viewed in the spatial domain [33]. To demonstrate this relationship, the fast Fourier transform (FFT) of simulated engine speed signatures for a 6-cylinder engine was calculated for various engine loads and engine speeds.…”

“…The accessory torque and the load torque are inputs to the model. The equations of motion using Newton's Second Law for the lumped parameter crank assembly model in the crank-angle domain are as outlined in [33]. The indicated torque, T i m , and the reciprocating torque, T r m , are given by…”

“…A transformation of these equations from time domain to the crank-angle domain is given in Ref. [33].…”

“…The existence of these lower frequencies is a good indication of cylinder faults which may be used for diagnostic purposes as proposed in [33]. Numerous works investigated the use of this lower frequency content for diagnostics [34][35][36][37][38][39][40].…”

Simplified method of torsional vibration calculation of marine power transmission system

“…Torsional vibration are the result of the pulsing torque of the reciprocating combustion engine [10] as well as unsteady propeller power output and the torsional elasticity of the power transmission system. All system components such as: crankshaft, intermediate shaft, propeller shaft, optional couplings and gears have to transmit the static and additionally dynamic torque.…”