Alcohol concentration sensor for automotive fuels

摘要

An electronic sensor (20) for measuring methanol content in gasoline fuels for automotive engines including a sensing coil (108/108') and a paired capacitance element (42,44/42', 44') that cooperates with the coil to define an oscillating circuit wherein the gasoline methanol fuel mixture is used as a dielectric for the capacitor elements of the sensor, a change in the methanol concentration in the fuel resulting in a change in the dielectric constant of the sensor (20) which results in a change in the resonant frequency of the capacitor elements (108/108', 42/44/42', 44'), and a microprocessor circuit (160) which responds to a change in the oscillating frequency to establish a control signal that may be used by an automotive powertrain controller (24) to effect appropriate adjustments in the air/fuel ratio and ignition timing for the engine (10) to compensate for variations in the methanol content of the fuel.