A remote acoustic engine oil quality sensor

A prototype model of an Acoustic Engine Oil Quality (AEOQ) sensor is presented. The AEOQ sensor utilizes changes in oil viscosity as an indicator of the oil quality. The supporting electronic circuitry employs a novel VCO based measurement set-up. The output signal from the VCO set-up is a DC voltage, which simplifies the accompanying circuitry, and is compatible with existing automotive electronics. Experimental results showed that the AEOQ sensor is capable of differentiating between engine oils of different grades and monitoring the degradation processes of oils due to their use in automotive engines and due to artificial contamination by dilution with water, ethylene glycol, and gasoline.