Vibration-Based Measurement of Activated Cylinders in Reciprocating Machines

Vibration signals from rotating and reciprocating machines provide insights into machine health and operating parameters. Reciprocating machines often feature cylinder deactivation systems for increased efficiency. This article presents a vibration-based method for the detection of activated cylinders in reciprocating machines. Simulated compressor vibration signals demonstrate the effect of cylinder conditions on spectral-coherence and mean-envelope-spectrum (MES) estimates. Physical parameters of the mechanical system and the results of the simulations advise the proposed method. With an appropriately chosen region of interest (ROI), the MES-based indicator (MESbI) correctly identified the number of activated cylinders of a four-cylinder reciprocating refrigeration compressor in both field and laboratory test setups. A discussion section addresses measurement uncertainty and calibration, and provides an example application.