An ultrasonic element generates an ultrasonic wave and converts an input ultrasonic wave into an electric signal. A transmission circuit outputs a drive signal to the ultrasonic element. A comparator circuit outputs a first detection signal when the electric signal becomes larger than a threshold value and outputs a second detection signal when the electric signal becomes smaller than the threshold value. An arithmetic circuit computes a distance of a propagation path of the ultrasonic wave based on a time difference between an output timing, at which the ultrasonic element outputs of the ultrasonic wave, and a liquid level timing, at which the comparator circuit outputs the first detection signal, and based on a propagation speed of the ultrasonic wave. A storage unit stores a time difference between the first detection signal and the second detection signal. The transmission circuit increases the drive signal, as the time difference decreases.
ULTRASONIC DISTANCE MEASURING DEVICE
2021-01-14
Patent
Electronic Resource
English
IPC: | G01F Messen des Volumens, des Durchflussvolumens, des Massendurchflusses oder des Füllstandes , MEASURING VOLUME, VOLUME FLOW, MASS FLOW, OR LIQUID LEVEL / B60K Anordnung oder Einbau von Antriebseinheiten oder von Kraft- bzw. Drehmomentübertragungen in Fahrzeugen , ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES / B60R Fahrzeuge, Fahrzeugausstattung oder Fahrzeugteile, soweit nicht anderweitig vorgesehen , VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR |
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