US Patent Application No. 13/938,230, Multifunctional fluid level and quality sensing device
This technology is about a multifunctional fluid level and quality sensing device including a fluid level sensor and a capacitive sensor for detecting fluid level, fluid quality, errors in the sensing device, and issues in a fluid delivery system. In detecting fluid level, impedance of the capacitive sensor is used in improving sensing performance of the fluid level sensor, while in detecting fluid quality and errors in the sensing device, an expected impedance range with an upper boundary value and a lower boundary value is calculated, and a fault is generated when the measured impedance value is out of the expected impedance range. The fluid level and quality sensing device can also be used in a fluid delivery system for detecting system issues, and the results can be used for further isolating errors in the system. Operating status of higher level system provides more information for this purpose.
Uniqueness and benefits of this technology:
1. A multi-functional fluid quality sensor includes a fluid level sensor and a capacitive sensor positioned in parallel with the fluid level sensor;
2. The fluid quality sensor is able to detect quality change in a fluid and errors in the quality sensor itself, including errors in the fluid level sensor;
3. In a DEF dosing system, the fluid quality sensor can also be used in detecting issues in the dosing system and in the engine system, including failures of vehicle speed sensors, and bypassing the engine after-treatment system.