Compared to diesel fuel at approx 7.05 lbs and gasoline at an average of 6.19 lbs, DEF is a relatively heavy product.Īs long as DEF is stored between 10 and 90 degrees Fahrenheit it should last at minimum of 1 year. No, DEF is a stable, non-toxic solution that can be transported without the use of a DOT approved hazardous substance placard.ĭEF weighs approximately 9 lbs per gallon. It commonly has a blue cap or other blue indicator to identify it as DEF (whereas diesel is often associated with the color green). It is stored in its on stand-alone tank, usually located right beside the diesel tank. No, DEF is injected into the diesel engine’s exhaust stream. Small quantities of DEF are injected into the exhaust upstream of a catalyst, then converts to ammonia in the exhaust stream and reacts with NOx over the catalyst to form harmless nitrogen gas and water.” Source: “SCR is the aftertreatment technology that treats exhaust gas downstream of the engine. Most diesel engine manufacturers have adopted SCR (Selective Catalytic Reduction) technology to meet 2010 EPA emissions standards. You may also see it referred to as NOx reduction agent AUS32 or AdBlue, both terms are common in Europe. It is a non-regulated non hazardous solution. It is a 32.5% solution of chemically pure Urea and 67.5% demineralized or deionized water. Check with your supplier of DEF to for more information on proper handling of DEF in extreme temperatures.ĭEF stands for Diesel Exhaust Fluid. If it is maintained at or above 120 degrees Fahrenheit it will slowly begin to form small amounts of ammonia. What happens to DEF if it exposed to high temperatures?ĭEF’s shelf life begins to degrade at high temperatures. Please consult your OEM website for more info (a list of OEM links is available on this site). There will be a progressive series of warning and indications coupled with performance reductions in the vehicle if the SCR is allowed to operate without DEF. Most manufactures have added new instrument gauges and indicators to vehicle dashboards or on-board displays. The answer to this question will vary based on manufacturer and year of your vehicle. What happens if my vehicle runs out of DEF? DEF filter changes only take a few minutes and replacement cycles will most likely be measured in years rather than months. The SCR system maintenance is relatively easy and conducted at the same intervals as normal chassis maintenance. What maintenance is required of an SCR system? Bodybuilders and Upfitters may have challenges working around the packaging of the new SCR systems as they take up more real estate on the chassis. The distribution system for DEF is still in its infancy and, although DEF is available at many locations throughout the country, operators in remote locations may find it more difficult to acquire. SCR requires the addition of DEF (Diesel Exhaust Fluid) to the system as needed consumption rates are dictated by engine usage. The disadvantages of SCR are mainly logistical. Also, the engine is not operating at its optimal combustion temperature, consequently reducing fuel efficiency and engine power.The advantages of an SCR system is that it allows the engine to operate at higher temperatures in order to optimize performance, meanwhile reducing NOx levels. However, the cooler combustion produces more particulate matter due to the less efficient operating temperature. The combustion temperature in the cylinder is reduced, thus lowering NOx production. In an EGR system, exhaust gas is cooled and recycled back through the engine. EGR was the technology that most manufacturers used to meet the first rounds of emissions regulations in 20. How does EGR work and why is this technology essentially being replaced by SCR?ĮGR stands for Exhaust Gas Recirculation.
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