Fuel volatility sensor and method based on capacitance measurement

摘要

A method and apparatus for determining a volatility of a fuel sample. A fuel sample is collected in a container and heated for a time period using a heater device. Periodically during the heating, the capacitance of the fuel sample and the temperature of the heater device are determined. After a time period passes, the volatility of the fuel sample is determined using the capacitance decrease and the temperature increase. Specifically, a voltage across the heater device is used, along with the current through the heater device to determine the resistance of the heater device, which gives the temperature of the heater device and the sample. The capacitance and temperature are compared to values derived from experimentation for fuels of varying DI. The first measurement of capacitance with a known sample volume can be used to determine the MTBE or ethanol content in gasoline fuels.