Integrated microstructure sensor element for detecting thermodynamic parameters of fluid e.g. oil in motor vehicle detects amplitude of third harmonic of voltage across heating element

摘要

A carrier body such as a board or wafer is provided with a heating element (15) in contact with the fluid. A device (20,21) is provided on or near the carrier body for applying an AC current to the heating element at defined frequency or in a defined frequency band. A device (22,23,24) detects the amplitude of the third harmonic of the voltage across the heating element. An Independent claim is also included for the use of the microstructure sensor element for detecting or monitoring the thermal conductivity or thermal capacity of oil in a motor vehicle.