Flow meter

A flow meter comprising:

• a first transducer configured to transmit a first signal and receive a second signal,
• wherein the first transducer is located at a first end of a fluid passage;
• a first transfer surface exposed to a fluid in the fluid passage and configured to transfer the second signal to the first transducer;
• a second transducer configured to transmit the second signal and receive the first signal,
• wherein the second transducer is located at a second end of the fluid passage;
• a second transfer surface exposed to the fluid in the fluid passage and configured to transfer the first signal to the second transducer;
• a controller configured to:
• determine a flow rate of fluid through the fluid passage based on a difference between a time-of-flight of the first signal and a-time-of-flight of the second signal.

A method for determining a flow rate through a fluid circuit of a vehicle, the method comprising:

• transmitting, from a first transducer on a first end of a flow tube, a signal traveling through a fluid in the flow tube to a second end of the flow tube;
• transferring, to a second transducer on the second end of a flow tube, the signal through a second transfer surface adjacent to the second transducer;
• transmitting, by the second transducer, a second ultrasonic signal traveling through the fluid in the flow tube to the first end of the flow tube;
• transferring, to the first transducer, the second signal through a first transfer surface adjacent to the first transducer;
• and
• determining, via a controller, a flow rate of the fluid based on a difference between a time-of-flight of the first signal and a-time-of-flight of the second signal.