Method and system for engine cooling system control

A coolant system coupled in a vehicle, comprising:

• a coolant overflow container having an internal recess for holding coolant;
• a vertical, hollow tube positioned adjacent to the container having an internal recess at a bottom-most level of the vertical tube;
• a first hose fluidly coupling a top portion of the container to a top portion of the vertical tube;
• a second hose fluidly coupling a bottom portion of the container to the bottom-most level of the vertical tube, wherein a level of fluid in the container equilibrates with a level of fluid in the vertical tube via a fluid transfer through each of the first and second hoses;
• a first ultrasonic sensor positioned in the internal recess at the bottom-most level of the vertical tube;
• a second sensor coupled to the vehicle external to the vertical tube for estimating a vehicle motion parameter;
• and
• a processor communicatively coupled to the first ultrasonic sensor and the second sensor, the processor configured with computer readable instructions that when executed during operation of the vehicle cause the controller to:
• estimate the fluid level in the vertical tube based on output from the first sensor;
• adjust the estimated fluid level based on output from the second sensor;
• infer the fluid level in the container based on the adjusted estimate of fluid level in the vertical tube;
• and
• adjust an operating parameter based on the inferred fluid level.