Bentley Tech Tips

What can you do to ensure the purity of the DEF you put in your trucks?

Since the 2010 emissions regulations, Selected Catalytic Reduction has been a fact of life, and with it Diesel Exhaust Fluid (DEF).

SCR doesn’t work without DEF. SCR is an aftertreatment technology that injects small amounts of DEF into an engine’s hot exhaust stream to reduce NOx emissions. DEF is made from urea, an ammonia-based chemical, and dionizeddeionized water. The proper solution is 32.5% high-purity urea mixed with very high-purity water.

When working properly in the exhaust, DEF vaporizes and forms ammonia and carbon dioxide. When the exhaust gas and ammonia are passed over the catalyst, NOx is converted to nitrogen and water. Not much can go wrong in the process as long as the DEF is properly formulated. But problems can occur when DEF is blended incorrectly or it becomes contaminated in the distribution process through incorrect procedures and handling.

Poor quality DEF can cause problems in the injection system that introduces the DEF into the exhaust. It can also cause premature failure of the catalyst. If the DEF has been contaminated and therefore is not cleaning the truck exhaust properly, a downstream NOx sensor will send a fault code to warn the driver of a problem. It will also light up the malfunction indicator light and in extreme cases cause the engine to derate.

What can you do to ensure the purity of the DEF you put in your trucks?

One way to ensure the quality of the DEF is to make sure it is API registered and meets ISO 22241 standards.

You should also always use equipment dedicated exclusively for dispensing and storing DEF. Don’t use funnels or bottles from other products. If you have to clean DEF fueling equipment, make sure to rinse it with de-mineralized water and not tap water. Do not refill previously used DEF containers, unless using a closed liquid system..

To ensure the quality of BlueDEF, PEAK Commercial and Industrial has developed a protocol to eliminate the potential for contamination of the product through the transportation and distribution process. The railcars and truck tankers that carry BlueDEF are dedicated to shipping the urea or DEF alone. Common carriers, too, must follow BlueDEF’s equipment purity specifications, which don’t allow them to washout tanks that previously carried another product. They must agree to dedicate their tankers solely to BlueDEF. Dedicated equipment with tamper-resistant seals is used at any transfer points to prevent contamination there.

In addition, each shipment comes with a certification verifying that it meets the ISO specification.

BlueDEF customers are also required to have closed liquid systems with valve coupling systems that seal the container opening on drums and totes. This is required to prevent dirt and debris from getting into the container.

Other tips for keeping DEF in proper condition including storing it at temperatures between 32 and 86 degrees out of direct sunlight. With proper care, DEF has a shelf life of approximately two years. But to ensure the purity of your DEF, a closed liquid system is the best option.