Cross Correlation-Based Ultrasonic Gas Flow Sensor With Temperature Compensation

In this paper, the design of an ultrasonic gas flow sensor with a low cost and low energy temperature compensation method based on time of flight measurement is presented. In order to minimize the cost, the proposed thermal compensation method, on the one hand, does not require a temperature sensor and, on the other hand, only requires an initial calibration at room temperature. The presented COTS (Commercial Off The Shelf) based sensor has been previously optimized at different levels: mechanical design, validation of the piezoelectric transducers and selection of the time of flight detection algorithm. As result, this paper presents a gas flow sensor based on a V-configuration pipe, using 200 kHz-piezoelectric transducers and a cross-correlation method based on the Hilbert Transform. The proposed design fully meets the accuracy requirements given by the EN14236 standard, improving the features of current commercial gas flow sensors in terms of cost, accuracy and power consumption.