Liquid level and composition sensing systems and methods using EMF wave propagation
First Claim
1. A method comprising:
- generating an RF signal at an operating frequency;
coupling the RF signal to a resonant circuit, the resonant circuit having a resonant frequency and including an inductor positioned proximate to urea in a tank;
calibrating the operating frequency of the RF signal to compensate for physical and/or electrical properties of said tank;
measuring a change in an electrical parameter associated with the resonant circuit caused by a variation in at least one property of the urea proximate to the inductor;
determining a fluid level and at least one property of the urea based on the change in the electrical parameter associated with the resonant circuit; and
transmitting the fluid level and at least one property of the urea to an external device.
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Accused Products
Abstract
An automotive urea solution monitoring device is deployed in conjunction with the urea tank of a selective catalytic reduction vehicle. An RF signal of a constant frequency may be generated across a resonant circuit, which may be comprised of an inductor and a PCB trace capacitor, or the like. Electromagnetic radiation is propagated into the automotive urea solution in the urea tank. The conductivity and dielectric properties of the liquid change the impedance of the discrete/trace capacitor and or the discrete/trace inductor. These changes are proportional to ammonia content, temperature, and/or level of the automotive urea solution in the urea tank and are preferably detected by a microcontroller, or the like, and then transmitted to a selective catalytic reduction vehicle engine management system, or the like.
33 Citations
19 Claims
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1. A method comprising:
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generating an RF signal at an operating frequency; coupling the RF signal to a resonant circuit, the resonant circuit having a resonant frequency and including an inductor positioned proximate to urea in a tank; calibrating the operating frequency of the RF signal to compensate for physical and/or electrical properties of said tank; measuring a change in an electrical parameter associated with the resonant circuit caused by a variation in at least one property of the urea proximate to the inductor; determining a fluid level and at least one property of the urea based on the change in the electrical parameter associated with the resonant circuit; and transmitting the fluid level and at least one property of the urea to an external device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification