公开(公告)号：US20200256985A1

公开(公告)日：2020-08-13

申请号：US16785815

申请日：2020-02-10

Applicant: DENSO CORPORATION

Inventor： Takuya KOIZUMI ,  Hironori IWAMIYA ,  Akihiro KONNO

IPC: G01S15/08

Abstract: A liquid level detector has an ultrasonic sensor connected thereto by two signal lines. When a drive signal is output from a drive circuit, the drive signal is output via an impedance matching circuit, thereby transmission and reception signals on the signal lines flow as complementary level signals. A receiver circuit obtains an amplified signal by amplifying the transmission and reception signals with a differential amplifier circuit, and by cutting a same phase noise signal.

公开(公告)号：US20210010848A1

公开(公告)日：2021-01-14

申请号：US16921141

申请日：2020-07-06

Applicant: DENSO CORPORATION

Inventor： Kyoko KUROKAWA ,  Takuya KOIZUMI ,  Akihiro KONNO ,  Hironori IWAMIYA

IPC: G01F23/296 ,  G01B17/00

Abstract: A first arithmetic circuit computes a propagation velocity of an ultrasonic wave based on a first time difference between an output timing, at which an ultrasonic element outputs an ultrasonic wave, and a reference timing, at which a comparator circuit outputs a detection signal on reflection off a distal end of a reference pipe, and a length of the reference pipe. A period circuit sets a propagation path detection period to detect a liquid level timing, at which the comparator circuit outputs the detection signal on reflection off the liquid level, based on a longest and shortest propagation path lengths and the propagation velocity. A second arithmetic circuit computes the length of the propagation path based on a second time difference, which is between the liquid level timing and the output timing during the propagation path detection period, and the propagation velocity.

公开(公告)号：US20210010847A1

公开(公告)日：2021-01-14

申请号：US16920886

申请日：2020-07-06

Applicant: DENSO CORPORATION

Inventor： Akihiro KONNO ,  Hironori IWAMIYA ,  Takuya KOIZUMI

IPC: G01F23/296 ,  B60R16/023 ,  B60K15/03

Abstract: 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.