Over the last decade, the automobile industry has significantly transformed how we make cars. There has been countless improvements and advancement that were seemingly impossible a decade ago. Any car owner out there will agree with me that there are major differences between today’s cars and the original German contraptions. The changes are so many such that it’s difficult to keep track. However, as a technician, car enthusiast, or even a first-time user of an automobile, it’s important to ensure you know everything about the fuel level sensor in your car. If you know nothing about them, don’t worry because you are in the right place. I will break it down for you.

Liquid level sensor 

What is a liquid level sensor? This is a device designed to measure volume, depth, and other metrics in a trunk tank or vessel. Liquid level sensors are most commonly used to measure and control the flow of liquid in and out of a vessel. They come in a variety of different forms that function differently and use different types of technologies. Here is a primer of some of the most common types of automotive liquid level sensors, how they work, and their pros and cons.

Ultrasonic level sensor

Sonic sensors are used for most liquid measurements because they are easy to install and don’t come into contact with the liquid. How do they work? Ultrasonic devices use sound waves to detect liquid level and work with a frequency range of between 20 kHz to 200 kHz. Ultrasonic sensors are sophisticated and give reliable and accurate liquid measurements. However, these sensors have their drawbacks especially when they are used for trunk tank measurement.

Sounds complicated? Let me explain. When a car travels, fuel moves and sloshes around in the tank. This makes it difficult for ultrasonic sensors to get accurate readings. The turbulence may also cause problems or damage the ultrasonic device especially if the liquid is a harmful chemical. How can you reduce liquid movement and splashes? I suggest you use a stilling well to diminish turbulence in the tank. A stilling well will help calm the liquid inside the pipe and make it easier for ultrasonic sensors to get good readings.

Temperature gradients can also affect ultrasonic sensors. How? Like I mentioned before, ultrasonic sensors use the speed of sound to calculate liquid level, and we all know that air temperatures influence the speed of sound. This means that a fluctuation in air temperature could cause a measurement error. How can you solve this problem? The best way to solve this issue is to turn off the temperature compensation feature to avoid over compensation. Installing a shade over the ultrasonic sensor can also help you lower the temperature.

Pressure sensors 

Pressure sensors detect liquid levels by measuring the pressure of liquids in a trunk tank. Pressure sensor devices are built using a technology that employs the mechanical properties of a liquid to measure its pressure and level. The good thing about these sensors is that they can deliver cost-effective reliability and have a long useful life. All you have to do is choose the right automotive pressure sensor. These sensors also operate effectively in extremely hostile environments.

Unfortunately, salty water and solvents can cause problems or damage a pressure sensor. These devices are also affected by fluctuating temperatures. Temperatures change the gravity of some liquids, and this may make it difficult for pressures sensors to give accurate results since they rely on the specific gravity of the liquid. How can you solve this problem? Due to how these devices operate, there is no effective way to solve this issue. Some people may advise you to use a temperature sensor in conjunction with the automotive pressure sensor to calculate a compensate reading, but I don’t think this is worth the effort when you can turn to other available options.

Mechanical float level gauges 

For me, mechanical float level gauges are the best option for measuring liquid level. These gauges are not affected as much by humidity, air pressure, external noises, air temperatures, paint mist, air current or type of gas. A mechanical float level gauge will still give accurate readings as long as the specific gravity does not go below the specific gravity of the device. If you travel a lot, then you should go for a mechanical float level gauge. This is because these devices handle turbulent better when compared to other sensors. At the same time, vibrations and turbulence attack the very structure of these devices. Therefore, I still advise you to use a stalling well when using a mechanical float level gauge.