Spx Corporation

James T Walters

Benjamin P Knapp

David L Vossen

Clarence B Allgor

David T Bach

Robert Trenary

This invention relates to a method and apparatus for diagnosing faulty cylinders in internal combustion engines. A probe produces a signal that is representative of the instantaneous angular velocity of the engine shaft. A Percent Power Contribution (PPC) parameter is computed by substracting the square of the instantaneous angular velocity at the beginning of a cylinder period from the square of the instantaneous angular velocity at the end of that cylinder's period and dividing this difference by the square of the average engine angular velocity. A value of this PPC parameter significantly less than zero indicates a faulty cylinder. An Average Energy Percent parameter (AEP) is computed by dividing the squares of the sampled instantaneous angular velocity values summed over a cylinder period by the number of samples in that period and by the square of the average engine angular velocity. A value of this AEP parameter significantly less than one indicates the previous cylinder in the firing order is faulty. The two parameters can be used independently or in combination to diagnose continuous and transient engine faults. Faulty cylinder indications are displayed on a monitor or communicated to an operator.

Method and apparatus for diagnosing faulty cylinders in internal

The invention is a method and apparatus for extracting and analyzing features in real time from primary or secondary ignition waveforms, including engine probes, sampling device, and a processor that extracts from the waveform features such as peak firing height, firing line duration, firing line slope, firing line noise, post firing line duration, primary oscillations, and dwell interval duration and compares them against fixed thresholds and running averages to detect anomalies. Anomalies are reported as they occur allowing diagnosis of transient events as well as steady conditions. Waveforms with or without anomalies may be stored and retrieved as needed.

Growing community of inventors

Kalamazoo, MI, United States of America

James T Walters