| 摘要 |
An apparatus and method is provided for detecting the level, composition, and temperature of a liquid fuel stored in a tank on a vehicle, as well as the tank pressure, and for transmitting this data via a multiplex bus to a central vehicle computer. The apparatus for collecting liquid fuel level data comprises first capacitive sensing means located within the fuel tank for storing a charge proportional to a full liquid level, second capacitive sensing means located within the tank for storing an instant liquid level charge proportional to the instant liquid level in the tank, and first processing means in communication with the multiplex bus and first and second capacitive sensing means for comparing the full liquid level charge to the instant liquid level charge to determine an absolute liquid level value and for outputting a corresponding fuel level data signal to the multiplex bus. The inventive method for collecting liquid level data comprises the steps of charging first and second capacitive sensors, discharging the first capacitive sensor through a resistive member and recording the discharge time as a first clock count representing the full-tank liquid level, discharging the second capacitive sensor through a resistive member and recording the discharge time as a second clock count representing an instant liquid level, then comparing the instant liquid level to the full-tank liquid level to determine an absolute liquid level in the tank.
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