Diesel Exhaust Fluid (DEF) for heavy-duty truck emissions treatment systems is made from a mixture of technically pure urea and purified water, and must be handled and stored properly to preserve its quality. This holds for drivers filling up on the road and shops that stock DEF.
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On the road, one of the main challenges for drivers is the knowing the brand of DEF they are being sold: Many fill up location bulk dispensers don’t identify fluid manufacturer and brand name, despite regulations in many states that require such information. It is difficult for drivers to confirm they are buying DEF that is licensed by American Petroleum Institute’s Diesel Exhaust Fluid Certification Program unless it is marked. Many diesel engine manufacturers recommend API-licensed DEF for their equipment.
Drivers accustomed to purchasing DEF in containers should look at the expiration on the bottle and be sure to use it before the date as the product has a limited shelf life. If a date is not present, they should ask for the most recently delivered DEF products.
Storage conditions also impact DEF quality. Fluid can be expected to have a minimum shelf life of 12 months or even longer in optimum conditions. Truck operators should check the label for storage temperature range, and API recommends that they don’t store fluid for too long once dispensed—especially if the storage area in the vehicle is routinely hotter than the recommended temperatures displayed on the label.
DEF FOR SHOP USE
API finds that the biggest misconception by fleet managers is the belief that if the urea concentration of their DEF is on spec, then the fluid meets the required quality. While it is absolutely true that the concentration is very important, there are other key quality characteristics built into the ISO 22241, Diesel engines — NOx reduction agent standard.
DEF is composed of 32.5 percent technically-pure urea in pure water. Each component is critical to the manufacture of treatment fluid that meets ISO 22241. Sub-standard urea—such as agricultural-grade product commonly used as fertilizer—or use of water derived directly from the public water system without proper treatment can introduce contaminants and metals that are detrimental to the life of the diesel engines’ Selective Catalytic Reduction (SCR) components, and can also affect the SCR system’s ability to reduce harmful NOx emissions.
Fleet managers should confirm DEF that meets the ISO quality standard. One way to do this is to ensure that their supplier is providing a Certificate of Analysis (or Quality) with every shipment that addresses all of the quality characteristics the specification requires. Fleets and drivers can check to see if the DEF they are buying is licensed through API’s real-time directory of licensees on the Institute website, www.api.org.
Handling, storage and dispensing of DEF for truck shops is very important: Temperatures during transport or at the point of storage or sale can harm the shelf life of DEF sold in containers. Fleet operators should make sure any stock is rotated to use the oldest fluid first. Proper storage temperatures are vital; conditions above 86°F will limit DEF shelf life over time. Some additional things to consider in fluid storage and handing include:
- Bulk tanks should be dedicated for DEF. Don’t switch products before thoroughly rinsing the tank with distilled or de-ionized water or on-spec DEF.
- A closed loop system for transferring DEF from a drum or bulk tank is recommended so contaminants don’t get into the fluid. This is particularly important in a shop or construction site that has dust or dirt in the air.
- Use dedicated equipment for dispensing DEF. Don’t use funnels, pitchers, hoses, etc. that are used for other fluids.
- Anything used for dispensing DEF should be cleaned with distilled or de-ionized water and followed by a DEF rinse. Don’t use tap water for cleaning.
It’s important for shop managers and drivers to know what they are putting into their DEF tanks. The quality of the fluid going into the vehicle is as important as the quality of the engine oils or fuels. Use of API-licensed Diesel Exhaust Fluid will ensure that product meets the high standards required by engine and vehicle manufacturers.
Jeffrey Harmening is Team Lead, Diesel Exhaust Fluid for American Petroleum Institute, Washington, D.C.
SMART FLUID PROCUREMENT: INSTRUMENTAL IN FLEET INVESTMENT PROTECTION
Diesel engines in trucks and other applications sold in the United States must meet stringent U.S. Environmental Protection Agency emissions treatment requirements. Many of those engines use Selective Catalytic Reduction (SCR) to meet the requirements. SCR is an emissions aftertreatment technology that converts nitrogen oxides (NOx) in the diesel engine exhaust stream into nitrogen and water vapor, two natural components in the air we breathe.
Diesel exhaust fluid (DEF) is an essential part of the process. It is injected into the diesel exhaust stream and the heat from the exhaust, the fluid, and a catalyst convert the NOx into the harmless gases. DEF is made from a 32.5 percent solution of technically pure urea with the rest of the mixture consisting of purified water. For the SCR unit to operate properly, the DEF must meet an exacting International Organization for Standardization purity threshold. This ensures that the DEF provides the purity required by diesel engine manufacturers and the quality to preserve the emissions control system and the environment.
The American Petroleum Institute plays an important role in ensuring that DEF products meet precise purity standards. The voluntary API Diesel Exhaust Fluid Certification Program is designed to certify and monitor the quality characteristics of DEF intended for use in vehicles with diesel engines.
Makers of DEF that have demonstrated that their products meet the performance requirements in ISO 22241 may be licensed to display the API Diesel Exhaust Fluid Certification Mark. Certification has many benefits for drivers and shops that purchase DEF. Truck drivers and fleets can find quality brands of DEF through a real-time directory, which lists API-licensed products that meet diesel engine manufacturer recommendations. This ensures that diesel engine warranties are protected and helps protect the overall investment in the truck. Licensing DEF also helps support the industry’s commitment to reduce NOx emissions.
API monitors DEF quality through the Aftermarket Audit Program by sampling and testing certified products purchased in marketplace to make sure they meet the quality specifications and program requirements. API certification requirements are enforced through action against companies not in conformance or falsely claiming certification.