US 2003/0117153 A1 · Fuel cell mixture sensor

Abstract

A sensor (40) includes a single capacitor (42) that operates in two different modes to obtain capacitance and conductance information when a mixture flows between the electrodes (44, 46) of the capacitor. The inventive sensor is particularly well-suited for making methanol content determinations within a mixture used to provide hydrogen to supply a fuel cell. Two different oscillators (180, 182) are selectively used to obtain the conductance and capacitance information. In a disclosed embodiment, a capacitor includes an outer electrode (44) that is received around an inner electrode (46) such that there is a spacing between the electrodes through which the mixture flows. The mixture acts as a dielectric of the capacitor allowing the conductance and capacitance measurements to be made. The example sensor includes a temperature sensor (76) conveniently supported within the inner electrode (46).

Claims20

Dependent claims

A sensor useful for measuring methanol content within a mixture, comprising:

a capacitor having a first, generally cylindrical electrode and a second electrode at least partially surrounding the first electrode, the electrodes being spaced apart such that the mixture flows between the electrodes;
a first oscillator that causes the capacitor to operate in a first mode to provide an indication of the capacitance of the capacitor when the mixture is between the electrodes;
a second oscillator that causes the capacitor to operate in a second mode to provide an indication of the conductance of the capacitor when the mixture is between the electrodes;
and
a controller that switches between the first and second oscillators to obtain the respective indications.

2 more elements

Dependencies are inferred from the claim text.

Fuel cell mixture sensor

Life of this patent

Fuel cell mixture sensor

Life of this patent

Abstract

Claims20