Diesel After-Treatment Systems



Diesel after-treatment system used on off-road diesel engines by a world leader in manufacturing of farm, forestry and construction equipment.


Due to emission-control regulations from the U.S. Environmental Protection Agency (EPA) the engine manufacturer needed a temperature sensor for their new engines to meet the new emissions requirements and achieve their design strategy. Specifically the manufacturer needed to precisely measure and control their diesel after-treatment system. The new product needed to withstand the ruggedness of the application and have high accuracy and fast time response. The solution needed to meet the EPA emission deadline yet fall within a specific budget range.


Watlow had a proven product that could meet the challenging environment of the application, the EXACTSENSE® thermocouple.

The EXACTSENSE provided the accuracy, time response and durability required to help the manufacturers improve the control of their diesel engine after treatment systems. The thermocouple also featured integrated electronics within a molded connector housing which provided high system accuracy resulting in improved fuel economy.

Watlow's engineering team collaborated with the manufacturer's engineers to enhance the existing thermocouple product with local interconnect network (LIN) message protocol. This provided the manufacturer with a signal easily read by their engine control unit (ECU). In addition, a 21 mm (0.83 in.) diameter tip was developed for the sensor that created a faster response time than competeing technologies. This helped the manufacturer achieve the time response required for the application.

The EXACTSENSE thermocouple includes WATCOUPLE™ sensing technology. This technology uses materials selected for their stability and longevity at high temperatures; making this thermocouple an ideal choice for this application. The resulting benefits included more efficient regeneration, better fuel economy and improved emissions to meet stringent global requirements.