A 2-wire fuel sender using ultrasonic technology determines the fuel level inside a tank by measuring the time it takes for sound waves to travel to the fuel surface and return. This is one common way a 2-wire sender operates.
Understanding the Technology
Unlike older mechanical or resistive types, a 2-wire ultrasonic fuel sender utilizes advanced sound wave technology.
Here's a breakdown of the process:
- Sound Generation: The sensor emits a high-frequency sound wave downwards towards the surface of the fuel.
- Reflection: This sound wave travels through the air (or other medium) in the tank and reflects off of the fuel surface.
- Echo Reception: The sensor listens for the echo returning from the fuel surface.
- Time Measurement: The sensor precisely measures the time elapsed between sending the sound wave and receiving the echo.
- Level Calculation: Using the speed of sound (which can be adjusted for temperature or tank environment) and the measured time, the sensor calculates the distance to the fuel surface. This distance is then used to determine the fuel level.
As described by references like the Fluid-Trac® sensor, the time for the echo to reflect off of the fuel and return to the fuel level sensor is used to calculate the level of the fuel inside the fuel tank. This method allows the sensor to work without needing internal moving parts or direct contact with the fuel, which can improve reliability and longevity.
The Role of the Two Wires
In this type of system, the "2-wire" configuration typically refers to the power supply and data transmission utilizing just two electrical connections.
| Wire | Function | Description |
|---|---|---|
| Wire 1 | Power In (+V) | Provides the necessary voltage for the sensor to operate. |
| Wire 2 | Ground / Signal Return | Completes the electrical circuit for power and often carries the signal (often a pulsed or modulated signal) back to the receiving unit (like a gauge or ECU). |
This setup allows the sensor to be easily integrated into various systems, requiring minimal wiring. The sensor draws power and sends its calculated fuel level data (or a signal representing it) back along these same two wires.
Practical Applications
Ultrasonic 2-wire fuel senders are common in various applications where accurate and reliable fuel level measurement is needed, especially in environments where traditional float sensors might be less suitable.
Examples include:
- Vehicle fuel tanks (cars, trucks, boats)
- Generator fuel tanks
- Industrial fluid storage tanks
- Agricultural equipment
By using ultrasonic pulses, the sensor avoids issues like fuel sloshing causing erratic readings (as the sensor averages measurements) and wear and tear on moving parts.
