PURPOSE: To detect the properties and the concentration of additive of an unknown fuel quickly and highly accurately by determining the difference between signals, representative of the dielectric constant of the unknown fuel, detected through first and second signal detecting means and then detecting one of heavy and light characteristics.
CONSTITUTION: A capacitive sensor 15 has first and second electrodes 18, 19 being applied 27 with first (second) voltages VH, VH (VH, VL) and applying a vector field to an unknown fuel flowing through a fuel channel 25 in order to detect a signal corresponding to the dielectric constant of the fuel. A processing circuit 28 receives the detection signal and delivers detection voltages VOA, VOB to a control unit 36. The unit 36 operates the difference ΔV between the voltages VOA, VOB and makes a decision whether the difference ΔV exceeds a voltage difference characteristic curve. If the answer is YES (NO), a decision is made that the fuel is heavy (light) and then an MTBE concentration M is calculated by selecting the voltage difference characteristics for heavy (light) fuel. This system allows quick and highly accurate decision of the properties of fuel and the concentration of additive.
KAMIOKA HIDEKI
WAKABAYASHI KATSUHIKO
