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The technical literature for engine misfire detection and faulty cylinder identification using crankshaft angular velocity measurements is reviewed. Current methods are categorized into three main approaches: threshold criteria, pattern recognition, and model based deconvolution. Real time detection of engine misfire using measured speed fluctuations is currently practical for a variety of engine and road conditions. Techniques to identify the location of specific faulty cylinders are less mature. An overview and comparison of current methods is presented. The implications of various assumptions made for the location of misfiring cylinders are explored. Remaining challenges are identified. A summary of relevant literature by author is presented. Finally, the current methodology is summarized.

An overview of analog and digital torsional vibration measurement methods is presented. Significant sources of digital measurement error are discussed in detail. Methods to minimize measurement errors are explored. A method to use multi-bit A/D data acquisition of a magnetic pickup signal to accurately measure tooth passing frequency with low sample rates is proposed. A frequency domain correction window is proposed which improves the frequency response of the standard digital demodulation technique. The proposed improvements enable accurate torsional vibration measurement with inexpensive A/D data acquisition equipment.