Flexible Fuel (FF) Sensor

The FF sensor is a capacitive device with a signal processing stage whose frequency varies with dielectric constant, conductivity and temperature of the methanol gasoline fuel mixture in its measuring cell. As the percentage of methanol in fuel mixture increases, the output frequency of the FF sensor signal will increase. A fuel mixture with 30 percent methanol will have a FF sensor signal output frequency of 60-100 Hz. A fuel mixture with 60 percent methanol will have a FF sensor signal output frequency of 90-130 Hz. The PCM uses the data to calculate correct air/fuel ratio and ignition spark advance.