Flexible Fuel Sensor
Flex Fuel Sensor
The flexible fuel (FF) sensor (Figure 29) is a capacitive device with a signal processing stage whose frequency varies with the dielectric constant, conductivity and temperature of the methanol-gasoline fuel mixture in its measuring cell. In general, as the percentage of methanol in the fuel mixture increases, the output frequency of the FF sensor signal will increase. For example, a fuel mixture that is 30% methanol will have a FF sensor signal output frequency between 60 and 100 Hz; 60% methanol will have a FF sensor signal output frequency between 90 and 130 Hz. The PCM uses the percent methanol information to calculate the correct air/fuel ratio and spark advance for the vehicle.
Figure 29: Flexible Fuel (FF) Sensor:
