Systems and methods for humidity determination and uses thereof

A method comprising:

• identifying an object that is stationary with respect to a vehicle, and wherein the object is within a transmission path of a single ultrasonic sensor coupled to the vehicle;
• selecting the single ultrasonic sensor to use for indicating relative humidity from a plurality of ultrasonic sensors positioned at various locations on the vehicle responsive to one or more onboard cameras detecting the object within the transmission path of the single ultrasonic sensor;
• indicating relative humidity from differences between pairs of reflected signals from the single ultrasonic sensor, each of the reflected signals having substantially equivalent transit time from the object back to the single ultrasonic sensor;
• indicating relative humidity from one or more sensors coupled to the vehicle other than the single ultrasonic sensor;
• selecting which relative humidity indication method to use in response to environmental or vehicle operating conditions;
• and
• adjusting vehicle operating conditions responsive to the selected relative humidity indication.

A system for a vehicle, comprising:

• one or more ultrasonic sensors positioned at various points on the vehicle;
• a combustion engine configured with a plurality of cylinders, each having a plurality of intake and exhaust valves;
• an exhaust manifold removably coupled to the plurality of cylinders via the plurality of exhaust valves;
• an exhaust gas oxygen sensor positioned in the exhaust manifold;
• and
• a controller storing instructions in non-transitory memory, that when executed, cause the controller to:
• in a first condition, indicate relative humidity from differences between pairs of reflected ultrasonic signals from a single ultrasonic sensor, where each of the reflected signals are determined to have a substantially equivalent transit time from an object back to the single ultrasonic sensor;
• in a second condition, indicate relative humidity via the exhaust gas oxygen sensor;
• and
• wherein the first condition includes an engine-on condition where the is combusting fuel, and wherein the second condition includes an engine-on non-engine fueling condition where the engine is not combusting fuel but where at least one pair of intake and exhaust valves are functioning to draw air through at least one cylinder.