What Is DEF?
DEF is a decomposition reactor that is injected into the SCR exhaust stream to break down nitrogen oxide in the diesel exhaust. DEF consists of automotive or environmental grade urea in solution combined with deionized water at a concentration ratio of 32.5 percent urea and 67.5 percent water. When purchasing DEF check for American Petroleum Institute certification on the package or from your supplier which means the product was manufactured to current concentration and purity standards. You will prolong the life of your catalytic system if you use only high-quality DEF.
What Happens If The DEF Is Not Pure?
SCR systems are sensitive and can collect on them any metals or non-DEF contaminants.This buildup will affect the way sensors work in the detection of the exhaust stream particulates. This is why commercial DEF is manufactured use deionized or demineralized water. Even adding small amounts of tap water to DEF will cause contamination. Use of contaminated or diluted DEF can, at a minimum, cause your SCR system to malfunction or even worse can cause costly damage to sensors filters and collectors. Warning signals from the catalyst alert the driver if contaminated DEF is entering the SCR system. The level of damage to the SCR system will be related to the concentration of contamination in the DEF.
What Kind Of Damage Can Occur?
Damage to the SCR system can include loss of surface area and reduced efficiency of the catalyst and possible secondary engine damage, creation of a sticky deposit or clogging of the DEF injectors. Engine damage may occur if contamination blocks pores in the catalyst where exhaust enters causing increased exhaust pressures. The SCR system may require servicing to restore its function or may need to be replaced. The warranty for the SCR system may not cover replacement as a result of using contaminated DEF.
What Are Some Basic Maintenance Recommendations?
The following steps can help you protect your SCR system and diesel engine.
- Purchase only highest quality certified DEF; certification should be located on the container, or can be obtained from the supplier.
- Purchase DEF at major truck stops, from fleet fuel suppliers or from auto parts or large retail stores make sure the filling nozzles are clean and free of dirt.
- Use only dedicated and non-reactive DEF storage and dispensing equipment because DEF is corrosive to some materials such as carbon steel, copper and brass.
- Do not put additives into your DEF because the concentration balance and purity will change and likely cause damage to your SCR system.
- Store at the recommended 12 to 90 degree temperature range for maximum shelf life; sunlight and high temperatures will reduce the shelf life of DEF.
- Track the age of your DEF; you can find a date code on commercial packaging.
- Check the purity of the DEF over time if you store or manage large volumes.
To learn more about storage, handling and management of DEF, contact Innovative Fueling Solutions. We are fuel industry specialists that supply DEF equipment, storage and dispensing systems, and serve Texas, Oklahoma, New Mexico and Colorado.