Friday, September 29, 2023

How NOx Sensors Work to Manage Diesel Engine Emissions

Diesel vehicles need to regulate their Nitrogen Oxide (NOx) emissions so that less pollutants are released into the atmosphere as mandated by law in most states. Manufacturers have been doing this with the use of Selective Catalytic Reduction (SCR) Technology so that air quality can be improved and diesel vehicles are regulated easily. A crucial component needed to supplement this system are the NOx sensors, a state of the art high-temperature sensor that monitors the levels of NOx being released into the air. This is critical to ensure that trucks and engines are meeting the state regulations at all times so we all get cleaner air. NOx sensors were also designed to monitor oxygen levels in the exhaust system.

Nox Sensor

So how does it actually work?

When the sensors detect that too much NOx is being emitted it communicates this to the SCR system so that it can adjust the urea levels accordingly. Their function therefore is to monitor the NOx conversion efficiency of the catalyst. The sensors can work as part of a feedback loop to the control unit on the emissions system to make real time adjustments and optimize NOx conversion. The ECU can than make adjustments to optimize NOx conversion performance. Most common after treatment systems will have two NOx sensors: One “upstream” on the turbo side of your Particulate Filter (DPF) and the second “downstream,” on the outlet side of your Catalyst (DOC). The two signals, sent directly to your Engine Control Module, are then compared to determine the “conversion efficiency” of your exhaust system. In the case of SCR technology, feedback can also be provided to the urea dosing system whereas in the case of lean NOx trap catalysts, a feedback loop could signal the regeneration of the trap.
The NOx sensor has a dual chamber design that measures both Oxygen and NOx content. As exhaust enters the sensor the Oxygen is pumped out and the NOx finds its way to a second chamber where the gas is exposed to a catalyst that calculates and reports that information to your computer.
If you’re thinking of changing your DPF or DOC, it’s a good idea to think about changing the NOx sensors so that everything runs smoothly. That’s where we come in. We carry NOx sensors for Mercedes Benz and Freightliners currently, but with many more vehicle applications on the way.
Chat with one of our technical sales specialists to find out what’s the right fit for your vehicle. Call 1-888-712-2525 then dial 1, or email us.

XeMODeX Inc. specializes in manufacturing and rebuilding electronic components for European automobiles. Our mission is to raise industry standards by providing customers with unparalleled service, superior products, and exceptional technical support. We strive to exceed the expectations of every customer from start to finish. By identifying the weak points and implementing a permanent solution, we effectively design and engineer products that surpass the durability and reliability of the OEM counterpart. Many of our units are available fully pre-programmed with software, making it truly plug and play. Many of our products include a Lifetime Limited Warranty, and access to an award-winning technical support team to assist you every step of the way. 

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