Fuel level capacitive sensor for automotive applications

摘要

The sensor includes a probe (12), fixed inside a fuel tank (10), connected to a signal processing circuit (14). The circuit includes a display (6) indicating the level of fuel in the tank. The probe is made up of two capacitors positioned along the height of the tank. The lower capacitor (18) is used as reference while the upper one (20) measures the liquid level. The two capacitors have a common electrode (22) which is a copper band placed on a pcb. Reference (24) and measuring electrodes (26) are covered by an insulating layer. An electrical conductor links the three electrodes to the processing electrodes.