LIQUID LEVEL AND COMPOSITION SENSING SYSTEMS AND METHODS USING EMF WAVE PROPAGATION

摘要

An automotive urea solution monitoring device (100) is deployed in conjun ction with the urea tank (102) of a selective catalytic reduction vehicle. A n RF signal of a constant frequency is generated across a resonant circuit ( 410), which is comprised of an inductor (411) and a PCB trace capacitor (412 ). 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 (412) and or the discre te/trace inductor (411). These changes are proportional to ammonia content, temperature, and/or level of the automotive urea solution in the urea tank a nd are detected by a microcontroller (401), and then transmitted to a select ive catalytic reduction vehicle engine management system.