The Diagnosis of Cylinder Power Faults in Diesel Engines by Flywheel Speed Measurement

Abstract

A technique for estimating the power contribution of each cylinder in a multi-cylinder diesel engine is developed as an engine diagnostic capability. Robust magnetic sensors are used to obtain a waveform of engine speed fluctuations over one engine cycle under steady state operating conditions. Adopting a simplified model of engine dynamics, a computer processes the time history by application of the discrete Fourier transform to reproduce the crankshaft torque waveform. Subtracting the engine inertia torque provides an estimate of the gas pressure torque waveform, from which the power contribution of individual cylinders can be determined.