KNOW HOW FUEL GAUGE WORKS IN VEHICLES !

We generally see fuel gauge in cars and motorbikes. They tell us the level of fuel in the fuel tank very accurately. Have you ever imagined how this gauge works and gives us reading that is always correct? We will understand the working of fuel gauge in this article.

The fuel gauge is a simple device. As a rule of thumb, it doesn’t even indicate/calculate the quantity of fuel in liters (or gallons), since all that is needed to alert the driver is the amount of fuel relative to the tank’s capacity. In this regard, fuel gauges have just two main markings – F for Full and E for Empty. Some have a “½” marking, too, to show half-tank.

The basic electromechanical fuel gauge consists of very few parts. The first part of this system is the sending unit. The sending unit is located in the fuel tank of the car. It consists of a float, usually made of foam, connected to a thin, metal rod. The end of the rod is mounted to a variable resistor. A resistor is an electrical device that resists the flow of electricity. The more resistance there is, the less current will flow. In a fuel tank, the variable resistor consists of a strip of resistive material connected on one side to the ground. A wiper connected to the gauge slides along this strip of material, conducting the current from the gauge to the resistor. 

If the wiper is close to the grounded side of the strip ( represented by the circuit in the figure), there is less resistive material in the path of the current, so the resistance is small (and current is high). If the wiper is at the other end of the strip, there is more resistive material in the current's path, so the resistance is large(and current is low).

The second part of this system is the fuel gauge which is a current meter. At low fuel levels the resistance will be high and at high levels the resistance will be low. The current from the resistor goes to a gauge that reacts to the amount of current flow. At high resistance the current will be low and the needle on the gas gauge will be low. At low resistance (full tank) the current will be high and the needle on the fuel gauge will reflect that. This is how the fuel gauge works.

Thank you for reading the article.