Patent ID: 7542870

Claim:
A module for determining a liquid level within a container of an automobile, the module comprising: a first transducer configured to be submerged within a liquid in the container; a second transducer configured to be submerged within the liquid in the container; a horn having a first end and a second end separated from the first end by a first distance, and positioned to guide ultrasonic impulses; and a controller configured to control the first transducer and the second transducer in a first mode and a second mode, and determine a quantity indicative of the liquid level within the container based on a first time of flight and a second time of flight, in the first mode, the controller is configured to generate a first electric signal and receive a second electric signal, the first transducer is configured to generate a first ultrasonic impulse in response to the first electric signal, and the second transducer is configured to sense a first reflected ultrasonic impulse and generate the second electric signal, wherein the first reflected ultrasonic impulse is a reflection of the first ultrasonic impulse, in the second mode, the controller is configured to generate a third electric signal and receive a fourth electric signal, the second transducer is configured to generate a second ultrasonic impulse in response to the third electric signal, and the first transducer is configured to sense a second reflected ultrasonic impulse and generate the fourth electric signal, wherein the second reflected ultrasonic impulse is a reflection of the second ultrasonic impulse, the controller further configured to switch between the first mode and the second mode.