| 摘要 |
<p>A sensor and method for measuring the concentration of alcohol in an alcohol-hydrocarbon mixture for use with flexible fuel vehicles. The sensor and method are characterized by a pair of detectors or sensing elements (27, 28) which detect absorbance of two different wavelength bands of energy transmitted through the fuel. The first wavelength band is absorbed by the alcohol and substantially unabsorbed by the hydrocarbons and other non-alcohols in the fuel mixture. The second or reference wavelength band is selected where the absorbance of alcohols and hydrocarbons is essentially the same and preferably essentially zero. The output of the two detectors or sensing elements (27, 28) is ratioed to provide a signal representative of the alcohol content of the fuel mixture. In a preferred embodiment, the sensing elements (27, 28) are included in a differential thermopile (98).</p> |
