Automotive Applications of Level Sensors Group: Calcium δ Eric Black Daniel Carter

Introduction Level sensors are not only used in Industrial and Chemical Applications Common household items use them as well These sensors range from simple mechanical devices to electronic or radiating tools

Level Sensors on Cars Cars contain two of the main kinds of level sensors –Float sensor –Visual sensor The float sensor is found in the gas tank, whereas there are a few visual sensors under the hood of the car

Gas Tank Float Sensor Initially, the float is at top of tank The attached wiper is closer to negative side of terminal –Less resistance –More current –Hotter Heating coil –Pulls Bimetallic strip so dashboard gauge displays full

Gas Tank Float Sensor As fuel leaves tank, float lowers Wiper moves further down resistor –More resistence –Less current –Coil cools –Strip pulls with contracting metal

Gas Tank Float Sensor Finally, after float hits bottom of tank, wiper is pulled to far right –Highest resistance –Lowest current –Coolest heating coil –Strip pulled gauge to empty

Gas Tank Float Sensor Pros: –Relatively simple mechanical design –Good for estimating level of fuel Cons: –Inaccurate when: Tank is completely full Tank is near empty –Doesn’t measure precise tank volume

Level Gauges Under the Hood Under the hood of a car, there are ways to check the level of various other fluids –Oil –Transmission –Coolant / Antifreeze –Windshield washer fluid These are checked using visual level gauges

Dipsticks Dipstick is inserted into engine Then removed with oil residue on tip Tip is marked with “full” and “add oil” markings Checking transmission fluid is similar Similary to the fuel tank float meter: –Good for estimating fluid level –Not a precise measurement of volume

Container Markings Small tanks under the hood containing windshield washer fluid and coolant have markings on the sides Only good for level estimation Can’t measure precise fluid volume