| 摘要 |
A capacitive liquid level sensor provides for a reliable and inexpensive means to measure fluid height. The capacitance measured at a sensor is interpreted by a control unit, which relays information regarding the liquid level to a display unit visible to the driver of the motor vehicle. In one embodiment, the sensor consists of two parallel electrode strips of a conductive material supported along their respective lengths by a substrate of an insulated material. The strips and the exposed side of the substrate are coated with a low conductivity porous material. The strips are connected to a control unit by a pair of electrical leads. When the sensor is immersed in a liquid, the control unit measures capacitance between the two strips and calculates the actual liquid height, based on the known dielectric constant of the liquid and the gas above it.
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