Diagnostic gasoline engine by phase demodulation method

Abstract

In gasoline (SI) engines, crankshaft instantaneous angular acceleration, which is evaluated by the second derivative of the crankshaft rotation respect with respect to time contains information for fault diagnostics. The instantaneous angular velocity of the crankshaft can be identified from a string of pulses for the engine electronic control unit (ECU). In this paper, the phase modulation signal is derived from the phase of an analytical signal which is evaluated by using the Hilbert Transform technique. To verify the signal analysis technique, the engine model created originally by John J. Moskwa needs to be extended to produce fluctuation of the crankshaft angular acceleration and to implement the extended model into the dSPACE equipment to control and diagnose SI engines. Key words: Engine fault diagnostics, crankshaft angular acceleration, phase demodulation.