Why Is Diesel Exhaust Fluid (DEF) Required?

DEF gallon containerThe pollutants emitted from the exhaust of diesel engines are extremely harmful to our environment and air quality. Federal standards limit exhaust emissions of five pollutants:

  • Hydrocarbons (HC)
  • Nitrogen Oxides (NOx)
  • Carbon Monoxide (CO)
  • Particulate matter (PM, for diesel vehicles only)
  • Formaldehyde (HCHO)

NOx and PM are the two most harmful of these five pollutants. NOx is the main cause of acid rain and ozone layer reduction. PM is composed by minute carbon particles and other toxic substances.

The Environmental Protection Agency (EPA) set in motion a series of tier standards that will eventually require all operating vehicles on the road, as well as off-road vehicles, to be in compliance with tier 4 standards. The latter having everything to do with diesel exhaust.

According to DieselNet’s website, “On May 11, 2004 the EPA signed the rule introducing Tier 4 emission standards, which are phased-in over the period of 2008-2015. The Tier 4 standards require that emissions of Particulate Matter (PM) and Nitrogen Oxides (NOx) be further reduced by about 90%. Such emission reductions can be achieved through the use of control technologies – including advanced exhaust gas after-treatment- similar to those required by the 2007-2010 standards for highway engines.”

What this means is that all engines in use will need to be in compliance with these standards. Manufacturing new vehicles isn’t a problem, but what about vehicles produced prior to 2007?

One solution is to use Diesel Exhaust Fluid (DEF) and a Selective Catalytic Reduction (SCR) system. By using an SRC system in conjunction with DEF, 94% of harmful pollutants are eliminated from diesel exhaust.

DEF is non-toxic and has a shelf life of about one year. However, it is susceptible to fierce summer and winter conditions. DEF freezes at about 11 degrees Fahrenheit. To prevent DEF from freezing there are solutions available.

Leave a Reply

Your email address will not be published. Required fields are marked *