Sense the Quality, Sense the Future


Urea Quality Sensor(UQS) contributes to enhance the functionality of the Urea-SCR system, which is indispensable system for detoxifying NOx exhaust from large diesel engines of trucks, construction and agricultural machinery, moreover becomes increasingly prevalent amongst passenger vehicles with smaller diesel engines. For the purpose, urea aqueous solution is sprayed in exhaust gas to reduce NOx to harmless N2 in SCR system. The UQS has a role in vigilance of the quality level of the solution, in particular its concentration level and accidental filling of diesel oil into the urea tank, which lead to emitting abnormal amount of NOx.
We are very proud of the fact that since the very first SCR system, our sensor keeps steady growth of sales in accordance with the stringent regulations on exhaust emission all over the globe.


Our UQS, unique from other products, employs the method of detecting thermal coefficient. Urea solution, like all other liquid, have peculiar heat transfer rate depending upon urea concentration. Thus, the sensor is designed to detect the infinitesimal difference in thermal coefficient.
This method actually has a long history as the measurement method but could not be robust enough to be installed as a sensor for vehicle. After resolving the engineering issues through further study and development, SUN-A successfully made practical use of the sensor mounted on a diesel engine. Our UQS guarantees long-term durability performance by uniform structure of platinum temperature sensor unit made by semi-conductor process. In conjunction with the unique structural design, our UQS offers the consistent robustness on dynamic conditions.


In order to fulfill the role of surveillance on urea solution, UQS is fabricated with the multi-functionality of measurement.

1. Urea concentration measurement
High resolution and accuracy should be maintained under various conditions.
2. Solution temperature measurement
To judge to start dosing urea solution after thawing(heating) operation, it is necessary to measure temperature.
3. Empty detection
To detect whether a tank is empty or not.
4. CAN communication
All the data is output conforming with CAN/SENT communication protocol.
5. Detect contamination of diesel oil
When diesel oil is adulterated by human error, the sensor should detect the existence of oil to prevent from being injected to the exhaust stream. Without a warning from sensor, all the exhaust system will be at the risk of burn out by the exhaust heat with combustible oil.

G3 model  Bottom-in Type

2013 launch. This product can be installed in that directly screwed or welded to the tank. Comparing the previous generation model, significant downsizing and light-weight are accomplished.

urea_tank bottomin_weld bottomin_screw

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G3 model  Lead Type

2014 launch. Comparing to the previous generation model, significant miniaturization and light-weight were achieved. This product can be assembled into variety of shape and size of the decompression module. Wide range of use at urea tank of various shape is also one of the features.

urea_tank lead_example

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