Capacitance-Based Fluid Level Sensor
First Claim
1. A fluid level sensor comprising:
- (A) a parallel plate capacitor-based probe located in a bottom portion of a fluid receptacle; and
(B) a controller that receives signals from the probe and that generates capacitance-dependent signals indicative of a fluid level in the receptacle.
3 Assignments
0 Petitions
Accused Products
Abstract
A fluid level sensor comprises a parallel plate capacitor coupled to an integrated circuit located in the bottom of an oil pan or other receptacle in which fluid level is being sensed. The sensor is preferably mounted on a drain plug for the receptacle. It includes an integrated circuit board encapsulated in a potting material disposed within the drain plug and a probe extending upwardly from the integrated circuit with its lower end also encapsulated with a resin such that its leads are protected by the resin encapsulating the integrated circuit. The probe may include one or more slotted plates in which capacitance bridges are formed within the slots or a plurality of parallel plates in which capacitance bridges are formed between adjacent plates. The sensor can be used to control operation of a gauge and/or an ignition control circuit for the machine'"'"'s engine.
26 Citations
27 Claims
-
1. A fluid level sensor comprising:
-
(A) a parallel plate capacitor-based probe located in a bottom portion of a fluid receptacle; and (B) a controller that receives signals from the probe and that generates capacitance-dependent signals indicative of a fluid level in the receptacle. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. The sensor of claim 8, wherein the controller generates a low fluid warning level only if the fluid level in the receptacle drops below a bottom of parallel plates of the probe.
-
9. A low fluid level detection system comprising:
-
(A) a fluid level sensor comprising i. a parallel plate capacitor-based probe located in a bottom portion of a fluid receptacle, and ii. a controller that receives signals from the probe and that generates capacitance-dependent signals indicative of a fluid level in the receptacle; and (B) a gauge that receives signals from the controller. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A method comprising:
sensing fluid levels in a receptacle using a parallel plate-type probe located in the receptacle. - View Dependent Claims (22, 23, 24, 25, 26)
-
27. A method comprising:
-
(A) connecting a parallel plate capacitor probe to a printed circuit board, the capacitor having a capacitance field having a frequency which varies with fluid levels thereacross; (B) encapsulating the printed circuit board in a potting material to form a unit; (C) mounting the unit in a receptacle.
-
Specification