| 摘要 |
A sensing apparatus for determining a property of a fuel such as a gasoline and ethanol blend known as flex fuel includes an acetal plastic tube with an inlet, an outlet and a fuel passage in between. One property is a dielectric constant. A pair of semi-circular shaped sensing plates are placed around the tube in concentric relation therewith, leaving the fuel passage unobstructed. A processing circuit on a printed circuit board (PCB) is located near and connected with the sensing plates. The circuit applies an excitation signal, senses a capacitance, and generates an output signal indicative of a property of the fuel. A shield for reducing EMI surrounds and encloses the sensing plates and the PCB. The sensed capacitance will increase with increasing concentration of ethanol in the fuel flowing through the passage. An interface connector allows the sensing apparatus to output the indicative signal to an engine controller.
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