1. Scope

This test method covers in field testing, first tier, for contamination of the urea-based diesel exhaust fluid (DEF) prescribed for use in the diesel engines equipped with selective catalytic reduction technology and is not more accurate determination of contamination in laboratory methods prescribed in ISO-22241-2.

Keywords

hydrocarbon, diesel exhaust fluid, water, urea, test strips, refractometer, contamination, solids, deionized

Rationale

Hydrocarbon poisoning of DEF as defined in ISO 22241-1 range for insoluble matter is defined as 28.2 which amounts to approximately .705/US Gallon in a typical container of 2.5 gallon. A major cause of breakdown (reported to be up to 50% of instances) of Select Catalytic Reduction devices is contamination by hydrocarbons. Risk mitigation of contamination is possible with infield evaluating DEF prior to receipt, introduction, and after introduction to the system. Four step process to test for impurities should be considered. The first step: Upon drawing the sample out of Diesel Emission Tank visual inspection, this should be done in a clear hard plastic cup checking for any discoloration and contamination. Diesel Exhaust Fluid (DEF) is usually clear, but when it comes in contact with copper or brass it will become light blue, if the DEF appears to be a rusty color this indicates that the DEF was in contact with steel or galvanized steel. (possibly in transport). REMEMBER DEF is heavier then diesel fuel and oil, therefore DEF will float on top of these fluids. It also smells slightly like ammonia Second step: A sample of the top level of DEF is taken as diesel is lighter then water Third step: Mid-range sample would be taken that would account for suspended solids Fourth step: A bottom sample is taken the mechanic is now checking form heavy dirt and buildup of sludge, (possible black mold growing on sending unit to be removed this test not cover in this standard), (refilling DEF tank). The sample which was used for the hydrocarbon testing was taken from BlueDef which is a registered trademark of Peak, (Old World Industries). The sample was taken from a 2.5-gallon tote (see attached Peak product sheet). BlueDef meets the ISO 22241 standard which is 20 kg/mg maximum for insoluble matter. This is not an endorsement by the ASTM nor this committee of this product or trademark. The sample was tested with Acustrip Hydrocarbon test strip, (part number 480508). One major cause of breakdowns and possible Select Catalytic Reduction devices (SCR) failure is contamination of UREA by hydrocarbons. Examples of these include diesel fuel windshield washer fluid and some aftermarket cleaners (toluene). Hydrocarbons that contaminate urea (DEF) can cause extensive damage to all internal components and moisture allows black mold to grow. Hydrocarbon contamination occurs in up to 50 percent of all SCR failures

The title and scope are in draft form and are under development within this ASTM Committee.